1. A light-emitting device comprising: a plurality of light sources configured to be disposed on a substrate; a light diffusion member configured to commonly cover the plurality of light sources; and a plurality of wavelength conversion members configured to be disposed between the light sources and the light diffusion member in a thickness direction and disposed in regions corresponding to the plurality of light sources in a plane, respectively, and configured to convert light with a first wavelength from the light sources into light with a second wavelength.

2. The light-emitting device as claimed in claim 1, further comprising: light reflection members configured to be disposed between the wavelength conversion members and the light diffusion members and disposed in regions corresponding to the plurality of light sources in the plane, respectively, and configured to reflect the light transmitted through the wavelength conversion members.

3. The light-emitting device as claimed in claim 1, 64 further comprising: a first connection member configured to connect two or more of the wavelength conversion members.

4. The light-emitting device as claimed in claim 3, wherein the wavelength conversion member and the first connection member are an integrated object formed of the same material.

5. The light-emitting device as claimed in claim 4, wherein a width of the first connection member is narrower than a width of the wavelength conversion member.

6. The light-emitting device as claimed in claim 1, wherein a plurality of wavelength conversion units including the plurality of wavelength conversion members arranged in a first direction and first connection members connecting the plurality of wavelength conversion members arranged in the first direction to each other are disposed in a second direction.

7. The light-emitting device as claimed in claim 1, wherein an interval between the light source and the wavelength conversion member is shorter than an interval between the light diffusion member and the wavelength 65 conversion member in the thickness direction.

8. The light-emitting device as claimed in claim 1, wherein a central point of the wavelength conversion member is identical to an optical axis of the light source in an in-plane direction and satisfies a condition expression (1) below: |1| < Tan-1(R1/L1) ... (1) where 1 is an angle at which emission intensity of the light source is 60% of the maximum peak (where an optical axis direction is assumed to be 0), R1 is a median value of a circumradius and an inradius in the wavelength conversion member, and L1 is a distance between the light source and the wavelength conversion member in the thickness direction.

9. The light-emitting device as claimed in claim 2, wherein a central point of the light reflection member is identical to an optical axis of the light source in an inplane direction and satisfies a condition expression (2) and a condition expression (3) below: Tan-1(R2/L2) < 27 ... (2); and R2 < R1 ... (3), where R2 is a median value of a circumradius and an inradius in the light reflection member, and L2 is a distance between the light reflection member and the light diffusion member 66 in the thickness direction.

10. The light-emitting device as claimed in claim 1, wherein the wavelength conversion member includes a quantum dot.

11. The light-emitting device as claimed in claim 1, further comprising: a plurality of light-shielding members configured to include a wall portion erected on the substrate to surround the light source in a plane intersecting an optical axis of the light source.

12. The light-emitting device as claimed in claim 11, wherein the wavelength conversion member is mutually separated from the light-shielding member.

13. The light-emitting device as claimed in claim 11, wherein a part of the light-shielding member reaches a straight line joining the light source and an end of the wavelength conversion member.

14. The light-emitting device as claimed in claim 11, further comprising: a reflection sheet configured to be disposed on the 67 substrate, wherein a part of the reflection sheet forms the lightshielding member.

15. The light-emitting device as claimed in claim 11, further comprising: a second connection member configured to connect two or more of the light-shielding members.

16. The light-emitting device as claimed in claim 15, further comprising: a first connection member configured to connect two or more of the wavelength conversion members, wherein a clip gripping the first connection member is installed in the second connection member.

17. A light-emitting device comprising: a plurality of light sources configured to be disposed on a substrate; a light diffusion member configured to commonly cover the plurality of light sources; and a plurality of wavelength conversion members configured to be disposed between the light sources and the light diffusion member in a thickness direction and have openings or notches in regions other than regions corresponding to 68 the plurality of light sources in a plane, respectively, and configured to convert light with a first wavelength from the light sources into light with a second wavelength.

18. A display device comprising: a liquid crystal panel; and a surface light-emitting device on a rear surface side of the liquid crystal panel, wherein the light-emitting device includes a plurality of light sources configured to be disposed on a substrate, a light diffusion member configured to commonly cover the plurality of light sources, and a plurality of wavelength conversion members configured to be disposed between the light sources and the light diffusion member in a thickness direction and disposed in regions corresponding to the plurality of light sources in a plane, respectively, and configured to convert light with a first wavelength from the light sources into light with a second wavelength.

19. An illumination device comprising: a light-emitting device, wherein the light-emitting device includes a plurality of light sources configured to be 69 disposed on a substrate, a light diffusion member configured to commonly cover the plurality of light sources, and a plurality of wavelength conversion members configured to be disposed between the light sources and the light diffusion member in a thickness direction and disposed in regions corresponding to the plurality of light sources in a plane, respectively, and configured to convert light with a first wavelength from the light sources into light with a second wavelength.

“LIGHT-EMITTING DEVICE, DISPLAY DEVICE, AND
ILLUMINATION DEVICE”
SONY CORPORATION, of 1-7-1 Konan, Minato-ku, Tokyo,
Japan
The following specification particularly describes the invention and the manner in
which it is to be performed.
2
FIELD
The present disclosure relates to a light-emitting
device, and a display device and an illumination device
including the light-emitting device.
BACKGROUND
Light-emitting devices using blue light emitting diodes
(LEDs) are adopted in backlights, illumination devices, or
the like of liquid crystal display apparatuses. For
example, Japanese Unexamined Patent Application Publication
No. 2012-155999 discloses a device which is a so-called
direct-type backlight and in which white light is formed by
a combination of a plurality of blue LEDs disposed on a
substrate and a wavelength conversion sheet covering all of
the blue LEDs. International Publication No. 2010/150516
discloses a surface light source which forms white light and
in which a blue LED, a reflection plate, a diffusion sheet,
and a fluorescent layer performing wavelength conversion are
stacked in order.
STATEMENT
Accordingly, an embodiment of the present disclosure
provides a light-emitting device including: a plurality of
light sources configured to be disposed on a substrate; a
light diffusion member configured to commonly cover the
3
plurality of light sources; and a plurality of wavelength
conversion members configured to be disposed between the
light sources and the light diffusion member in a thickness
direction and disposed in regions corresponding to the
plurality of light sources in a plane, respectively, and
configured to convert light with a first wavelength from the
light sources into light with a second wavelength.
OBJECT
The principal object according to an embodiment of the
present disclosure is to provide a light-emitting device
capable of emitting light with high regularity in a plane
with high efficiency, and a display device and an
illumination device including the light-emitting device.
SUMMARY
In Japanese Unexamined Patent Application Publication
No. 2012-155999, however, yellow is considered to tend to
become strong in the periphery of the blue LED rather than
immediately above the blue LED. In International
Publication No. 2010/150516, the configuration is
complicated and there is a concern of a luminance difference
between a region immediately above the blue LED and a region
of the periphery of the blue LED being recognized as grain
irregularity. In light-emitting devices used as surface
4
light sources, in general, it is strongly preferable to
efficiently emit light for which luminance irregularity or
color deviation is small in a plane.
It is desirable to provide a light-emitting device
capable of emitting light with high regularity in a plane
with high efficiency, and a display device and an
illumination device including the light-emitting device.
According to an embodiment of the present disclosure,
there is provided a light-emitting device including: a
plurality of light sources configured to be disposed on a
substrate; a light diffusion member configured to commonly
cover the plurality of light sources; and a plurality of
wavelength conversion members configured to be disposed
between the light sources and the light diffusion member in
a thickness direction and disposed in regions corresponding
to the plurality of light sources in a plane, respectively,
and configured to convert light with a first wavelength from
the light sources into light with a second wavelength.
According to another embodiment of the present disclosure, a
display device and an illumination device include the lightemitting
device.
According to still another embodiment of the present
disclosure, there is provided another light-emitting device
including: a plurality of light sources configured to be
disposed on a substrate; a light diffusion member configured
5
to commonly cover the plurality of light sources; and a
plurality of wavelength conversion members configured to be
disposed between the light sources and the light diffusion
member in a thickness direction and have openings or notches
in regions other than regions corresponding to the plurality
of light sources in a plane, respectively, and configured to
convert light with a first wavelength from the light sources
into light with a second wavelength.
In the light-emitting device, the display device, and
the illumination device according to the embodiments of the
present disclosure, the plurality of wavelength conversion
members are disposed between the light sources and the light
diffusion member in the thickness direction and are disposed
in the regions corresponding to the plurality of light
sources in the plane, respectively. Thus, wavelength
conversion to the light with the second wavelength is
appropriately performed while reducing the intensity of the
light with the first wavelength directly incident on the
light diffusion member from the light sources. The number
of used wavelength conversion members is reduced compared to
a case in which one sheet-shaped wavelength conversion
member is installed across the entire surface.
In the other light-emitting device according to the
embodiment of the present disclosure, the wavelength
conversion members are disposed between the light sources
6
and the light diffusion member in the thickness direction
and have the openings or the notches in the regions other
than the regions corresponding to the plurality of light
sources in the plane, respectively. Thus, the wavelength
conversion to the light with the second wavelength is also
appropriately performed while reducing the intensity of the
light with the first wavelength directly incident on the
light diffusion member from the light sources. The number
of used wavelength conversion members is reduced compared to
the case in which one sheet-shaped wavelength conversion
member is installed across the entire surface.
According to the light-emitting device according to the
embodiment of the present disclosure, it is possible to
efficiently emit light for which luminance irregularity or
color deviation is small in a plane. Therefore, the display
device using the light-emitting device can have display
performance such as excellent color reproduction. The
illumination device using the light-emitting device can
illuminate a target object more regularly. The advantages
according to the embodiment are not limited thereto, but any
of the advantages to be described below may be obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described with
reference to the accompanying drawings, throughout which
7
like parts are referred to by like references, and in which:
Fig. 1 is a perspective view illustrating an example of
the entire configuration of a light-emitting device
according to a first embodiment of the present disclosure;
Fig. 2A is a plan view illustrating the configuration
of main units of the light-emitting device illustrated in
Fig. 1;
Fig. 2B is a sectional view illustrating the
configuration of main units of the light-emitting device
illustrated in Fig. 1;
Fig. 3 is an expanded perspective view illustrating a
wavelength conversion unit of the light-emitting device
illustrated in Fig. 1;
Fig. 4 is a perspective view illustrating a
configuration of a holding mechanism of the wavelength
conversion unit of the light-emitting device illustrated in
Fig. 1;
Fig. 5 is a perspective view illustrating another
configuration of the holding mechanism of the wavelength
conversion unit of the light-emitting device illustrated in
Fig. 1;
Fig. 6 is a characteristic diagram illustrating a
relation between emission intensity of a light source and an
angle with respect to an optical axis in the light-emitting
device illustrated in Fig. 1;
8
Fig. 7 is an explanatory diagram illustrating a method
of regulating a radius of the wavelength conversion unit of
the light-emitting device illustrated in Fig. 1;
Fig. 8 is an explanatory diagram illustrating a method
of regulating the radius of the light reflection member of
the light-emitting device illustrated in Fig. 1;
Fig. 9A is an explanatory diagram illustrating a first
optical path mode in the light-emitting device illustrated
in Fig. 1;
Fig. 9B is an explanatory diagram illustrating a second
optical path mode in the light-emitting device illustrated
in Fig. 1;
Fig. 9C is an explanatory diagram illustrating a third
optical path mode in the light-emitting device illustrated
in Fig. 1;
Fig. 10 is a perspective view illustrating the entire
configuration of a light-emitting device according to a
second embodiment of the present disclosure;
Fig. 11A is a sectional view illustrating the
configuration of main units of a light-emitting device
according to a third embodiment of the present disclosure;
Fig. 11B is an expanded sectional view illustrating a
light source and the vicinity of the light source of the
light-emitting device illustrated in Fig. 11A;
Fig. 11C is a perspective view illustrating a
9
configuration of main units of the light-emitting device
illustrated in Fig. 11A;
Fig. 11D is a perspective view illustrating another
configuration of the main units of the light-emitting device
illustrated in Fig. 11A;
Fig. 11E is a sectional view illustrating a first
modification example of a light-shielding member illustrated
in Fig. 11A;
Fig. 11F is a sectional view illustrating a second
modification example of the light-shielding member
illustrated in Fig. 11A;
Fig. 11G is a sectional view illustrating a third
modification example of the light-shielding member
illustrated in Fig. 11A;
Fig. 11H is a sectional view illustrating a fourth
modification example of the light-shielding member
illustrated in Fig. 11A;
Fig. 11I is a sectional view illustrating a first
modification example of the light-emitting device
illustrated in Fig. 11A;
Fig. 11J is a perspective view illustrating a second
modification example of the light-emitting device
illustrated in Fig. 11A;
Fig. 11K is a sectional view illustrating the second
modification example of the light-emitting device
10
illustrated in Fig. 11A;
Fig. 12 is a perspective view illustrating the outer
appearance of a display device according to a fourth
embodiment of the present disclosure;
Fig. 13A is an exploded perspective view illustrating a
body unit illustrated in Fig. 12;
Fig. 13B is an exploded perspective view illustrating a
panel module illustrated in Fig. 13A;
Fig. 14A is a perspective view illustrating the outer
appearance of an electronic book (Application Example 1) on
which a display device according to an embodiment of the
present disclosure is mounted;
Fig. 14B is a perspective view illustrating the outer
appearance of another electronic book (Application Example
1) on which a display device according to an embodiment of
the present disclosure is mounted;
Fig. 15 is a perspective view illustrating the outer
appearance of a smartphone (Application Example 2) on which
a display device according to an embodiment of the present
disclosure is mounted;
Fig. 16A is a perspective view illustrating the outer
appearance of a digital camera (Application Example 3) on
which a display device according to an embodiment of the
present disclosure is mounted, when viewed from a front
side;
11
Fig. 16B is a perspective view illustrating the outer
appearance of the digital camera (Application Example 3) on
which the display device according to an embodiment of the
present disclosure is mounted, when viewed from a rear side;
Fig. 17 is a perspective view illustrating the outer
appearance of a note-type personal computer (Application
Example 4) on which a display device according to an
embodiment of the present disclosure is mounted;
Fig. 18 is a perspective view illustrating the outer
appearance of a video camera (Application Example 5) on
which a display device according to an embodiment of the
present disclosure is mounted;
Fig. 19A is a front view, a left side view, a right
side view, a top view, and a bottom view illustrating the
outer appearance of a mobile phone (Application Example 6)
which is in a closed state and on which a display device
according to an embodiment of the present disclosure is
mounted;
Fig. 19B is a front view and a side view illustrating
the outer appearance of the mobile phone (Application
Example 6) which is in an opened state and on which a
display device according to an embodiment of the present
disclosure is mounted;
Fig. 20 is a perspective view illustrating the outer
appearance of a first illumination device (Application
12
Example 7) including a light-emitting device according to an
embodiment of the present disclosure;
Fig. 21 is a perspective view illustrating the outer
appearance of a second illumination device (Application
Example 8) including a light-emitting device according to an
embodiment of the present disclosure;
Fig. 22 is a perspective view illustrating the outer
appearance of a third illumination device (Application
Example 9) including a light-emitting device according to an
embodiment of the present disclosure;
Fig. 23A is a characteristic diagram illustrating
distributions of tristimulus values X, Y, and Z in
Experiment Example 1-1;
Fig. 23B is a characteristic diagram illustrating
distributions of tristimulus values X, Y, and Z in
Experiment Example 1-2;
Fig. 23C is a characteristic diagram illustrating
distributions of tristimulus values X, Y, and Z in
Experiment Example 1-3;
Fig. 23D is a characteristic diagram illustrating
distributions of tristimulus values X, Y, and Z in
Experiment Example 1-4;
Fig. 24A is a characteristic diagram illustrating a Cx
distribution and a Cy distribution in a central region of a
light emission surface in Experiment Example 1-1;
13
Fig. 24B is a characteristic diagram illustrating a Cx
distribution and a Cy distribution in a central region of
the light emission surface in Experiment Example 1-4;
Fig. 25A is a characteristic diagram illustrating a Cx
distribution and a Cy distribution in an end region of the
light emission surface in Experiment Example 1-1;
Fig. 25B is a characteristic diagram illustrating a Cx
distribution and a Cy distribution in an end region of the
light emission surface in Experiment Example 1-2;
Fig. 25C is a characteristic diagram illustrating a Cx
distribution and a Cy distribution in an end region of the
light emission surface in Experiment Example 1-3;
Fig. 25D is a characteristic diagram illustrating a Cx
distribution and a Cy distribution in an end region of the
light emission surface in Experiment Example 1-4;
Fig. 26 is a characteristic diagram illustrating
luminance distributions of a Y component in Experiment
Examples 2-1 to 2-5;
Fig. 27A is a characteristic diagram illustrating a
luminance distribution in the central region of the light
emission surface in Experiment Example 2-1;
Fig. 27B is a characteristic diagram illustrating a
luminance distribution in the central region of the light
emission surface in Experiment Example 2-2;
Fig. 27C is a characteristic diagram illustrating a
14
luminance distribution in the central region of the light
emission surface in Experiment Example 2-3;
Fig. 27D is a characteristic diagram illustrating a
luminance distribution in the central region of the light
emission surface in Experiment Example 2-4;
Fig. 27E is a characteristic diagram illustrating a
luminance distribution in the central region of the light
emission surface in Experiment Example 2-5;
Fig. 28A is a schematic diagram illustrating the
configuration of main units of a light-emitting device in
Experiment Example 3-1;
Fig. 28B is a schematic diagram illustrating the
configuration of main units of a light-emitting device in
Experiment Example 3-2;
Fig. 28C is a schematic diagram illustrating the
configuration of main units of a light-emitting device in
Experiment Example 3-3;
Fig. 29A is a characteristic diagram illustrating
distributions of tristimulus values X, Y, and Z in
Experiment Example 3-1;
Fig. 29B is a characteristic diagram illustrating
distributions of tristimulus values X, Y, and Z in
Experiment Example 3-2;
Fig. 29C is a characteristic diagram illustrating
distributions of tristimulus values X, Y, and Z in
15
Experiment Example 3-3;
Fig. 30A is a schematic diagram illustrating the shape
of a wavelength conversion unit and a light reflection
member according to a first modification example;
Fig. 30B is a schematic diagram illustrating the shape
of a wavelength conversion unit and a light reflection
member according to a second modification example;
Fig. 30C is a schematic diagram illustrating the shape
of a wavelength conversion unit and a light reflection
member according to a third modification example;
Fig. 31A is a schematic diagram illustrating the shape
of a wavelength conversion unit and a light reflection
member according to a fourth modification example;
Fig. 31B is a schematic diagram illustrating the shape
of a wavelength conversion unit and a light reflection
member according to a fifth modification example; and
Fig. 32 is a schematic diagram illustrating a
wavelength conversion unit according to a sixth modification
example.
DETAILED DESCRIPTION OF EMBODIMENTS
Hereinafter, embodiments of the present disclosure will
be described in detail with reference to the drawings. The
description will be made in the following order.
1. First Embodiment
16
Light-emitting Device Including Plurality of Wavelength
Conversion Units with Belt-like Shape
2. Second Embodiment
Light-emitting Device Including Wavelength Conversion
Unit in Which Plurality of Openings Are Formed in Net-like
Shape
3. Third Embodiment
Light-emitting Device Including Plurality of Lightshielding
Members Each Surrounding Light Source and
Modification Examples
4. Fourth Embodiment (Display Device: Liquid Crystal
Display Device)
5. Application Examples 1 to 6 of Display Device
6. Application Examples 7 to 9 of Illumination Device
7. Experiment Examples
First Embodiment
Configuration of Light-emitting Device 1
Fig. 1 is a perspective view illustrating the entire
configuration of a light-emitting device 1 according to a
first embodiment of the present disclosure. Fig. 2A is an
expanded plan view illustrating main units of the lightemitting
device 1 and Fig. 2B is a sectional view
corresponding to the plan view of Fig. 2A. The lightemitting
device 1 is used as, for example, a backlight that
17
illuminates a transmissive liquid crystal panel from a rear
side or an illumination device indoors or the like. The
light-emitting device 1 includes, for example, a plurality
of light sources 10 (not illustrated in Fig. 1), wavelength
conversion units 20, and an optical sheet 30. The plurality
of light sources 10 are arranged on a reflection substrate
40, for example, in a matrix form. The optical sheet 30 is
placed on the vertexes of a plurality of studs 50 erected on
a front surface 40S of the reflection substrate 40. Thus,
the optical sheet 30 is disposed to face the reflection
substrate 40 so that the plurality of light sources 10 are
commonly covered. The front surface 40S and a rear surface
30S of the optical sheet 30 are held by the plurality of
stubs 50 at a given distance L4. The wavelength conversion
units 20 are disposed between the light sources 10 and the
optical sheet 30 in the Z direction. The wavelength
conversion units 20 are disposed to occupy regions
corresponding to the plurality of light sources 10 on the XY
plane, respectively.
In the present specification, a distance direction of
the optical sheet 30 and the reflection substrate 40 is
referred to as a Z direction (anteroposterior direction). A
horizontal direction and a vertical direction on main
surfaces (largest surface) of the optical sheet 30 and the
reflection substrate 40 are referred to as an X direction
18
and a Y direction, respectively.
The light source 10 is a point light source and is
specifically configured to include a light-emitting diode
(LED). For example, the light source 10 faces a rear
surface 20S2 (Fig. 2B) of the wavelength conversion unit 20.
The wavelength conversion units 20 are disposed between
the light source 10 and the optical sheet 30 so that, for
example, chromogenic characteristics are improved by
converting the wavelength of light from the light sources 10
and emitting converted light. The wavelength conversion
units 20 each include a direct upper portion 21 that covers
a region (direct upper region) corresponding to each light
source 10 and a region of the periphery thereof and a
connection portion 22 that connects the direct upper
portions 21 mutually adjacent in, for example, the X
direction, and thus entirely extend in the X direction. The
plurality of wavelength conversion units 20 are arranged in
the Y direction. For example, the connection portion 22 is
inserted into a slit 54 between a pedestal 52 and a pressure
53 formed in a midslope portion of a pillar 51 of the stud
50 to be held. Alternatively, as expanded and illustrated
in Fig. 3, the wavelength conversion unit 20 may be fixed by
allowing a clip 55 to grip the connection portion 22. In
this configuration, a distance L1 between the rear surface
20S2 of the wavelength conversion unit 20 and the light
19
source 10 is maintained constantly. In Figs. 1, 2A, and 2B,
an insertion direction of the connection portion 22 into the
slit 54 is assumed to be the -Y direction, but an embodiment
of the present disclosure is not limited thereto. For
example, as illustrated in Fig. 4, the connection portions
22 inserted into the slit 54 in the +Y direction and the
connection portions 22 inserted into the slits 54 in the -Y
direction may be alternately disposed. Alternatively, for
example, as illustrated in Fig. 5, the connection portions
22 inserted into the slits 54 and the connection portions 22
gripped by the clips 55 may be alternately disposed. It may
not be necessary to hold all of the plurality of existing
connection portions 22 by the slits 54 or the clips 55.
The distance L1 between the light source 10 and the
wavelength conversion unit 20 is preferably shorter than a
distance L3 between the optical sheet 30 and the wavelength
conversion unit 20 in the Z direction. This is because a
more uniform luminance distribution can be obtained compared
to a case in which the distance L1 is equal to or greater
than the distance L3. That is, when the wavelength
conversion unit 20 is close to the optical sheet 30, the
contour of the wavelength conversion unit 20 may be
projected to the optical sheet 30, and thus there is a
concern of the contour of the wavelength conversion unit 20
being viewed from the outside.
20
In the embodiment, the example in which the wavelength
conversion unit 20 is installed as an integrated object in
which the direct upper portion 21 and the connection portion
22 are formed of the same material has been described.
However, the connection portion 22 may be formed of a
material different from that of the direct upper portion 21,
e.g., a resin which does not perform wavelength conversion.
Here, a width W22 of the connection portion 22 is preferably
narrower than a width W21 of the direct upper portion 21
(see Fig. 2A). This is because an amount of used material
is reduced, and thus there are advantages of reducing cost
and reducing a weight.
The wavelength conversion unit 20 includes a
fluorescent body (fluorescent substance) such as fluorescent
pigment or fluorescent dye or a light-emitter, such as a
quantum dot, having a wavelength conversion action. The
wavelength conversion unit 20 may be obtained by processing
a resin including such a fluorescent substance or a light
emitter in a sheet shape or may be printed in a
predetermined region on another transparent substrate.
Alternatively, the wavelength conversion unit 20 may be
obtained by sealing a layer of a fluorescent substance or a
fluorescent body between two transparent films.
The wavelength conversion unit 20 is excited by light
with a first wavelength coming from the light source 10 and
21
incident from the rear surface 20S2, performs wavelength
conversion by a principle of fluorescence emission, and
emits light with a wavelength (second wavelength) different
from the first wavelength from a front surface 20S1. The
first and second wavelengths are not particularly limited.
However, for example, when the light is used for a display
device, the light with the first wavelength may be blue
light (for example, a wavelength of about 440 nm to about
460 nm) and the light with the second wavelength may be red
light (for example, a wavelength of 620 nm to 750 nm) or
green light (for example, a wavelength of 495 nm to 570 nm).
That is, the light source 10 is a blue light source. In
this case, the wavelength conversion unit 20 converts the
wavelength of the blue light into the wavelength of the red
light or green light.
The wavelength conversion unit 20 preferably includes a
quantum dot. The quantum dot is a particle with a major
diameter of about 1 nm to about 100 nm and has a discrete
energy level. Since the energy state of the quantum dot
depends on the size of the quantum dot, it is possible to
select a light-emitting wavelength freely by changing the
size of the quantum dot. The color of light emitted from
the quantum dot has a narrow spectrum width. A color gamut
is expanded by combining light with such steep peaks.
Accordingly by using the quantum dot as a wavelength
22
conversion substance, it is possible to expand the color
gamut easily. The quantum dot has high responsiveness and
the light of the light source 10 can be efficiently used.
The quantum dot has high stability. The quantum dot is, for
example, a compound of a group 12 element and a group 16
element, a compound of a group 13 element and a group 16
element, or a compound of a group 14 element and a group 16
element and is, for example, CdSe, CdTe, ZnS, CdS, Pds,
PbSe, or CdHgTe.
The central point of the direct upper portion 21 of the
wavelength conversion unit 20 is identical to an optical
axis CL of the light source 10 on the XY plane (see Fig.
2A). In this case, the direct upper portion 21 may be
disposed at a position in which a condition expression (1)
below is satisfied. This is because a component with high
energy intensity in the light from the light source 10 is
prevented from being incident directly on the optical sheet
30 and luminance irregularity is sufficiently reduced.
|1| < Tan-1(R1/L1) ... (1)
Here, 1 is an angle at which the emission intensity of the
light source 10 is 60% of the maximum peak (where an optical
axis direction is assumed to be 0) (see Fig. 6). R1 is a
radius obtained as a median value of a circumradius rr1 and
an inradius rr2 in the direct upper portion 21 of the
wavelength conversion unit 20 (see Fig. 7). L1 is a
23
distance between the light source 10 and the wavelength
conversion unit 20 in the Z direction.
The reflection substrate 40 is a plate-shaped or a
sheet-shaped member installed to face the rear surface 20S2
of the wavelength conversion unit 20. The reflection
substrate 40 returns, to the wavelength conversion unit 20
or the optical sheet 30, light emitted from the light source
10, reaching the wavelength conversion unit 20, and then
returned from a light reflection member 60 (described below)
or light emitted from the light source 10, reaching the
optical sheet 30, and then returned from the optical sheet
30. The reflection substrate 40 has a function of, for
example, reflection, diffusion, or dispersion, and thus can
improve front luminance by efficiently using the light from
the light source 10.
The reflection substrate 40 is formed of, for example,
a foaming polyethylene-telephthalate (PET), a silvervaporized
film, a multilayer reflection film, or a white
PET. When the reflection substrate 40 has a specular
reflection (mirror reflection) function, the front surface
of the reflection substrate 40 is preferably subjected to
silver evaporation, aluminum evaporation, a multilayer
reflection process, or the like. When the reflection
substrate 40 is vested with a minute shape, the reflection
substrate 40 may be integrally formed by a method such as
24
molten extrusion molding or heat press molding using a
thermoplastic resin or may be formed by applying an energy
ray (for example, an ultraviolet ray) curing resin onto a
substrate formed of, for example, PET and then transferring
a shape to the energy ray curing resin. Here, examples of
the thermoplastic resin include a polycarbonate resin, an
acrylic resin such as a polymethyl methacrylate resin
(PMMA), a polyester resin such as polyethylene
telephthalate, an amorphous copolymer polyester resin such
as methylmethacrylate styrene copolymer (MS), polystyrene
resin, and polyvinylchloride resin. When a shape is
transferred to the energy ray (for example, an ultraviolet
ray) curing resin, the substrate may be glass.
The light-emitting device 1 may further include, for
example, four wall portions 41 that are erected in the outer
edge of the reflection substrate 40 and surround the
plurality of light sources 10 and wavelength conversion
units 20 from four sides. The inner surface of the wall
portion 41 has a reflection function and an auxiliary
wavelength conversion unit 42 is installed in a part of the
wall portion 41. The wavelength conversion unit 42 is
formed of, for example, the same material as the wavelength
conversion unit 20 and is a belt-like member that is formed
in the inner surface of the wall portion 41 and extends in
the X direction and the Y direction. The wavelength
25
conversion unit 42 has a wavelength conversion function as
in the wavelength conversion unit 20 and supplements the
function of the main wavelength conversion unit 20.
The optical sheet 30 is installed to face the front
surface 20S1 of the wavelength conversion unit 20 and
includes, for example, a diffusion plate, a diffusion sheet,
a lens film, and a polarization separation sheet. In Figs.
1 and 2B, only one optical sheet 30 is illustrated among the
plurality of optical sheets 30. By installing the optical
sheet 30, it is possible to launch light emitted from the
light source 10 or the wavelength conversion unit 20 in an
inclination direction in the front direction, and thus it is
possible to further improve the front luminance.
The light-emitting device 1 further includes the light
reflection members 60 that reflect light transmitted through
the direct upper portion 21 of the wavelength conversion
unit 20. The light reflection members 60 are disposed in
regions corresponding to the plurality of light sources 10
on the XY plane, respectively. In the embodiment, the case
in which the light reflection members 60 are disposed to
come into contact with the front surface 20S1 has been
described. However, the light reflection members 60 may be
separated from the front surface 20S1 when the light
reflection members 60 are disposed between the direct upper
portions 21 and the optical sheet 30.
26
The central point of the light reflection member 60 is
identical to the optical axis CL of the light source 10 on
the XY plane (see Fig. 2A). In this case, the light
reflection member 60 may be disposed at a position in which
a condition expression (2) and a condition expression (3)
below are satisfied. This is because a region in which
light transmitted through the direct upper portion 21 from
the light source 10 and incident directly on the optical
sheet 30 is blocked by the light reflection member 60 is
restricted with an appropriate size and it is difficult to
view a dark portion occurring by disposing the light
reflection member 60. Accordingly, the luminance
irregularity is further reduced.
Tan-1(R2/L2) < 27 ... (2)
R2 < R1 ... (3)
Here, R2 is a radius obtained as a median value of a
circumradius rr3 and an inradius rr4 in the light reflection
member 60 (see Fig. 8). L2 is a distance between the light
reflection member 60 and the optical sheet 30 in the Z
direction.
Operations and Advantages of Light-emitting Device 1
In the light-emitting device 1, the light source 10 is
a point light source. Therefore, the light emitted from the
light source 10 is spread from the light emission center of
27
the light source 10 in all of the 360 directions, passes
through the optical sheet 30, and is finally observed as
emitted light. Specifically, optical path modes are
classified into three optical path modes.
For example, as illustrated in Fig. 9A, a first optical
path mode is a mode in which light emitted from the light
source 10 is incident on a region of the direct upper
portion 21 of the wavelength conversion unit 20 superimposed
on the light reflection member 60. In this case, after the
light from the light source 10 is subjected to the
wavelength conversion by the direct upper portion 21 of the
wavelength conversion unit 20, the light is reflected from
the light reflection member 60. The reflected light from
the light reflection member 60 receives an action of
reflection, diffusion, dispersion, or the like on the front
surface 40S of the reflection substrate 40 and is oriented
toward the wavelength conversion unit 20 or the optical
sheet 30.
For example, as illustrated in Fig. 9B, a second
optical path mode is a mode in which light emitted from the
light source 10 is incident on a region other than the
region of the direct upper portion 21 of the wavelength
conversion unit 20 superimposed on the light reflection
member 60. In this case, after the light from the light
source 10 is subjected to the wavelength conversion by the
28
direct upper portion 21 of the wavelength conversion unit
20, the light passes through the vicinity of the light
reflection member 60 and is oriented toward the optical
sheet 30.
For example, as illustrated in Fig. 9C, a third optical
path mode is a mode in which light emitted from the light
source 10 does not pass the direct upper portion 21 of the
wavelength conversion unit 20 and is incident directly on
the optical sheet 30. In this case, the light from the
light source 10 is not subjected to the wavelength
conversion to remain as, for example, blue light, and is
oriented toward the optical sheet 30.
In the light-emitting device 1 according to the
embodiment, the direct upper portions 21 of the plurality of
wavelength conversion units 20 are disposed between the
light sources 10 and the optical sheet 30 in the Z direction
and are disposed in the regions corresponding to the
plurality of light sources 10 on the XY plane, respectively.
Thus, it is possible to appropriately perform the wavelength
conversion to the light with the second wavelength (for
example, green light or red light) while reducing the
intensity of the light with the first wavelength incident
directly on the optical sheet 30 from the light source 10.
Further, an amount of used constituent material can be
reduced compared to a case in which one sheet-shaped
29
wavelength conversion member is installed across the entire
surface. Accordingly, in the light-emitting device 1, it is
possible to reduce the weight and it is possible to
efficiently emit light for which luminance irregularity or
color deviation on the XY plane is small.
Since the light reflection member 60 is installed above
the direct upper portion 21 of the wavelength conversion
unit 20, flatness of light emission intensity from the
optical sheet 30 is improved. This is because the light
coming from the light source 10 and transmitted through the
direct upper portion 21 is not incident directly on the
optical sheet 30, but the light can be reflected from the
light reflection member 60, can be reflected again from the
reflection substrate 40, and then can be guided toward the
optical sheet 30.
Second Embodiment
Configuration of Light-emitting Device 2
Fig. 10 is a perspective view illustrating the entire
configuration of a light-emitting device 2 according to a
second embodiment of the present disclosure. The lightemitting
device 2 has the same configuration as the lightemitting
device 1 according to the foregoing first
embodiment except that one wavelength conversion unit 20A is
included instead of the plurality of wavelength conversion
30
units 20.
The wavelength conversion unit 20A has a plurality of
openings 23 or notches 24 selectively formed in regions
other than the regions corresponding to the plurality of
light sources 10, respectively. In the wavelength
conversion unit 20A, the mutually adjacent direct upper
portions 21 are connected to each other by the connection
portions 22, as in the wavelength conversion unit 20. The
wavelength conversion unit 20A is different from the
wavelength conversion unit 20 in that not only the direct
upper portions 21 arranged in the X direction but also the
direct upper portions 21 arranged in the Y direction are
connected by the connection portions 22.
Operations and Advantages of Light-emitting Device 2
The light-emitting device 2 has the same functions as
those of the light-emitting device 1 according to the
foregoing first embodiment. The number of components is
reduced and an assembly operation is simplified.
Third Embodiment
Configuration of Light-emitting Device 3
Fig. 11A is a sectional view illustrating the
configuration of main units of a light-emitting device 3
according to a third embodiment of the present disclosure.
31
Fig. 11B is an expanded diagram illustrating the main units
of the light-emitting device 3. Figs. 11C and 11D are
perspective views illustrating the configuration of the main
units of the light-emitting device 3. In Fig. 11D, the
wavelength conversion unit 20 and the light reflection
member 60 are not illustrated. The light-emitting device 3
has the same configuration as the light-emitting device 1
according to the foregoing first embodiment except that a
plurality of light-shielding members 70 are included on the
reflection substrate 40.
Each light-shielding member 70 includes a wall portion
71 erected on the front surface 40S of the reflection
substrate 40 to surround each light source 10 in a plane
intersecting (for example, perpendicular to) an optical axis
Z1 of each light source 10. The wall portion 71 may be
fixed directly to the front surface 40S. For example, as in
a light-shielding member 70A illustrated in Fig. 11E in a
first modification example, the wall portion 71 may be
installed along with the light source 10 on a base portion
72 on a flat plate.
The rear surface 20S2 of the wavelength conversion unit
20 and a top surface 71T of the light-shielding member 70
may be separated from each other by a distance L6 (see Fig.
11A). This is because when the wavelength conversion unit
20 comes into contact with the light-shielding member 70,
32
there is a concern of heat generated in the light source 10
not being sufficiently radiated to the outside and
overheating occurring in the light source 10 and the
vicinity of the light source 10. For example, the distance
L6 may be equal to or greater than 1/3 of a distance between
the rear surface 20S2 and the front surface 40S. This is
because the light emitted from the light source 10 is
emitted to the outside without being confined between the
wavelength conversion unit 20 and the light-shielding member
70, and thus light emission efficiency is improved.
For example, an inner surface 71S of the wall portion
71 facing the light source 10 is inclined to be more distant
from the light source 10 as the inner surface 71S is closer
from the front surface 40S to the wavelength conversion unit
20. However, as in a light-shielding member 70B illustrated
in Fig. 11F in a second modification example, for example,
the inner surface 71S may be perpendicular to the XY plane
along the front surface 40S of the reflection substrate 40.
As in a light-shielding member 70C illustrated in Fig. 11G
in a third modification example, for example, the inner
surface 71S may be a concave surface. As in a lightshielding
member 70D illustrated in Fig. 11H in a fourth
modification example, for example, the inner surface 71S may
be a convex surface. When the inner surface 71S is a
concave surface as in the light-shielding member 70C, most
33
of the light emitted from the light source 10 is introduced
to the direct upper portion 21 of the wavelength conversion
unit 20 located in a direct upward direction. On the other
hand, when the inner surface 71S is a convex surface as in
the light-shielding member 70D, most of the light emitted
from the light source 10 is reflected upward obliquely
rather than in the direct upward direction. Accordingly,
even when the distance L6 is short, the light emitted from
the light source 10 can be extracted efficiently from a gap
between the wavelength conversion unit 20 and the lightshielding
member 70.
In the light-emitting device 3, as illustrated in Fig.
11B, a part of the wall portion 71 erected on the front
surface 40S may reach a straight line LB1 joining a light
emission point Z0 of the light source 10 formed on the front
surface 40S and an end 21T of the direct upper portion 21.
In this case, of the light emitted from the light emission
point Z0 and travelling without being blocked by the wall
portion 71 of the light-shielding member 70, a light beam
LB2 for which an emitting angle  with respect to the
optical axis Z1 is the maximum is incident on the direct
upper portion 21. Therefore, of the light emitted from the
light emission point Z0, all of the light travelling without
being blocked by the wall portion 71 is incident on the
direct upper portion 21. The light blocked by the wall
34
portion 71 is absorbed to the wall portion 71 to become heat
or is reflected from the inner surface 71S of the wall
portion 71. Accordingly, the light from the light source 10
is reliably prevented from being incident directly on the
optical sheet 30 without being subjected to the wavelength
conversion by the wavelength conversion unit 20. Since the
inner surface 71S is inclined toward the direct upper
portion 21, most of the light reflected from the inner
surface 71S is incident on the direct upper portion 21 and
contributes to an improvement in the luminance of the lightemitting
device 3. To promote reuse of the light, the wall
portion 71 may be formed of, for example, a high-reflection
material such as white polycarbonate. In the abovedescribed
light-shielding members 70B to 70D in the second
to fourth modification examples, a part of the wall portion
71 erected on the front surface 40S may reach the straight
line LB1 joining the light emission point Z0 of the light
source 10 and the end 21T of the direct upper portion 21.
The light-emitting device 3 may further include
connection portions 73 connecting two or more of the lightshielding
members 70. In this case, the light-shielding
member 70 and the connection portion 73 may be an integrated
object formed of the same material. In this case, the
number of components can be reduced. The connection portion
73 is fixed to the reflection substrate 40 by, for example,
35
a screw 75. Both of the connection portions 22 and 73
extend in, for example, the X-axis direction and have parts
overlapping each other in the thickness direction (Z-axis
direction). A clip 74 gripping the connection portion 22
may be installed in the connection portion 73. Between the
connection portions 22 and 73, for example, a columnar
spacer 76 may be erected on the connection portion 73. This
is because the distance L1 between the direct upper portion
21 and the light source 10 and the distance L6 between the
direct upper portion 21 and the top surface 71T of the wall
portion 71 are each maintained regularly in the plane since
the connection portions 22 and 73 are maintained at a more
regular interval in the plane. The spacer 76 may be formed
as an integrated object with the connection portion 73.
Operations and Advantages of Light-emitting Device 3
In the light-emitting device 3, the plurality of lightshielding
members 70 including the wall portions 71 erected
to surround the light sources 10 are installed. Therefore,
of the light from the light source 10, the component
incident directly on the optical sheet 30 without being
subjected to the wavelength conversion by the wavelength
conversion unit 20 is further reduced. In particular, when
the part of the direct upper portion 21 of the wavelength
conversion unit 20 reaches the straight line LB1 joining the
36
light source 10 and the end 20T, the entire light emitted
from the light emission point Z0 and travelling without
being blocked by the wall portion 71 is incident on the
direct upper portion 21. In this case, it is possible to
reliably prevent the light from the light source 10 from
being incident directly on the optical sheet 30 without
being subjected to the wavelength conversion by the
wavelength conversion unit 20. Accordingly, in the lightemitting
device 3, it is possible to further alleviate
occurrence of luminance irregularity or color deviation (in
particular, irregularity of the blue component) in the
plane. For example, the inner surface 71S of the wall
portion 71 surrounding the light source 10 is inclined to be
more distant from the light source 10 (expanded on the XY
plane) as the inner surface 71S is closer from the front
surface 40S to the wavelength conversion unit 20.
Therefore, it is possible to improve use efficiency of the
light from the light source 10.
First Modification Example of Third Embodiment
As illustrated in Fig. 11I, a substrate 43 and a
reflection sheet 44 disposed thereon may be used instead of
the reflection substrate 40. In this case, parts of the
reflection sheet 44 may function as light-shielding members.
That is, wall portions 45 erected on the substrate 43 are
37
formed by curving the parts of the reflection sheet 44. The
wall portions 45 are molded to surround the light source 10
on the XY plane perpendicular to the optical axis Z1. Even
in this case, by adjusting the heights of the wall portions
45, the same advantages as those of the foregoing third
embodiment are expected.
Second Modification Example of Third Embodiment
In the foregoing third embodiment, the connection
portion 73 is fixed to the reflection substrate 40 by the
screw 75, but a fixing portion is not limited to the screw
75. For example, as in a modification example illustrated
in a perspective view of Fig. 11J and a sectional view of
Fig. 11K, a protrusion 77 may be formed in the connection
portion 73 and the protrusion 77 may be inserted to be fixed
to a hole 40H formed in the front surface 40S of the
reflection substrate 40. In this case, a claw 77A may be
formed in the protrusion 77 and may lock into a locking
portion 40HK inside the hole 40H formed in the reflection
substrate 40. In this case, the wall portion 71, the
connection portion 73, the clip 74, and the protrusion 77
may be integrated. Further, as illustrated in Fig. 11K, the
connection portion 73 may be curved so that a lower surface
73LS forms a concave surface. By curving the connection
portion 73 in this way, it is possible to prevent the wall
38
portion 71 installed at the end of the connection portion 73
from being away from the front surface 40S when the
protrusion 77 is inserted to be fixed to the hole 40H.
Fourth Embodiment
Fig. 12 is a diagram illustrating the outer appearance
of a display device 101 according to a fourth embodiment of
the present disclosure. A display device 101 includes the
light-emitting device 1 and is used as, for example, a thin
type television device. The display device 101 has a
configuration in which a body unit 102 with a flat plate
shape for image display is supported by a stand 103. The
display device 101 is used as a standing type device by
attaching the stand 103 to the body unit 102 and placing the
stand 103 on the horizontal surface of a floor, a shelf, a
rack, or the like in the attached state. However, the
display device 101 may also be used as a wall-mounting type
device in a state in which the stand 103 is detached from
the body unit 102.
Fig. 13A illustrates the exploded body unit 102
illustrated in Fig. 12. The body unit 102 includes, for
example, a front outer case member (bezel) 111, a panel
module 112, and a rear outer case member (rear cover) 113 in
this order from the front side (viewer side). The front
outer case member 111 is a frame-shaped member that covers
39
the front circumference of the panel module 112 and a pair
of speakers 114 are disposed on the lower side. The panel
module 112 is fixed to the front outer case member 111. A
power substrate 115 and a signal substrate 116 are mounted
on the rear surface of the panel module 112 and a mounting
bracket 117 is fixed to the rear surface. The mounting
bracket 117 is used for attachment of a wall mounting
bracket, attachment of a substrate, and attachment of the
stand 103. The rear outer case member 113 covers the rear
surface and the side surfaces of the panel module 112.
Fig. 13B illustrates the exploded panel module 112
illustrated in Fig. 13A. The panel module 112 includes, for
example, a front casing (top chassis) 121, a liquid crystal
panel 122, a frame-shaped member (middle chassis) 80, the
optical sheet 30, the wavelength conversion units 20, the
reflection substrate 40, a rear casing (back chassis) 124,
and a timing controller substrate 127 in this order from the
front side (viewer side).
The front casing 121 is a frame-shaped metal component
that covers the front circumference of the liquid crystal
panel 122. The liquid crystal panel 122 includes, for
example, a liquid crystal cell 122A, a source substrate
122B, and a flexible substrate 122C, such as a chip on film
(COF), connecting the liquid crystal cell 122A and the
source substrate 122B. The frame-shaped member 80 is a
40
frame-shaped resin component that holds the liquid crystal
panel 122 and the optical sheet 30. The rear casing 124 is
a metal component that is formed of iron (Fe) and houses the
liquid crystal panel 122, an intermediate casing 123, and
the light-emitting device 1. The timing controller
substrate 127 is also mounted on the rear surface of the
rear casing 124.
In the display device 101, the light from the lightemitting
device 1 is transmitted selectively by the liquid
crystal panel 122 so an image is displayed. Here, as
described in the first embodiment, since the display device
101 includes the light-emitting device 1 in which the color
regularity in the plane is improved, the display quality of
the display device 101 is improved.
In the foregoing embodiment, the case in which the
display device 101 includes the light-emitting device 1
according to the first embodiment has been described.
However, the display device 101 may include the lightemitting
device 2 according to the second embodiment instead
of the light-emitting device 1.
Application Examples of Display Device
Hereinafter, application examples of the foregoing
display device 101 to electronic apparatuses will be
described. Examples of the electronic apparatuses include a
41
television apparatus, a digital camera, a note-type personal
computer, a portable terminal such as a mobile phone, and a
video camera. In other words, the foregoing display device
can be applied to electronic apparatuses displaying video
signals input from the outside or video signals generated
therein as images or videos in all kinds of fields.
Application Example 1
Fig. 14A illustrates the outer appearance of an
electronic book to which the display device 101 according to
the foregoing embodiment is applied. Fig. 14B illustrates
the outer appearance of another electronic book to which the
display device 101 according to the foregoing embodiment is
applied. Both of the electronic books include, for example,
a display unit 210 and a non-display unit 220. The display
units 210 are configured by the display device 101 according
to the foregoing embodiment.
Application Example 2
Fig. 15 illustrates the outer appearance of a
smartphone to which the display device 101 according to the
foregoing embodiment is applied. The smartphone includes,
for example, a display unit 230 and a non-display unit 240.
The display unit 230 is configured by the display device 101
according to the foregoing embodiment.
42
Application Example 3
Figs. 16A and 16B illustrate the outer appearance of a
digital camera to which the display device 101 according to
the foregoing embodiment is applied. Fig. 16A illustrates
the outer appearance when the digital camera is viewed from
the front side (object side) and Fig. 16B illustrates the
outer appearance when the digital camera is viewed from the
rear side (image side). The digital camera includes, for
example, a light-emitting unit 410 for flash, a display unit
420, a menu switch 430, and a shutter button 440. The
display unit 420 is configured by the display device 101
according to the foregoing embodiment.
Application Example 4
Fig. 17 illustrates the outer appearance of a note-type
personal computer to which the display device 101 according
to the foregoing embodiment is applied. The note-type
personal computer includes, for example, a body 510, a
keyboard 520 used to perform an operation of inputting text
or the like, and a display unit 530 displaying an image.
The display unit 530 is configured by the display device 101
according to the foregoing embodiment.
Application Example 5
43
Fig. 18 illustrates the outer appearance of a video
camera to which the display device 101 according to the
foregoing embodiment is applied. The video camera includes,
for example, a body unit 610, a subject photographing lens
620 installed on the front side of the body unit 610, a
start/stop switch 630 at the time of photography, and a
display unit 640. The display unit 640 is configured by the
display device 101 according to the foregoing embodiment.
Application Example 6
Figs. 19A and 19B illustrate the outer appearance of a
mobile phone to which the display device 101 according to
the foregoing embodiment is applied. In the mobile phone,
for example, an upper casing 710 and a lower casing 720 are
connected by a connection unit (hinge unit) 730. The mobile
phone includes a display 740, a sub-display 750, a picture
light 760, and a camera 770. Of the constituent elements,
the display 740 or the sub-display 750 is configured by the
display device 101 according to the foregoing embodiment.
Application Examples of Illumination Device
Figs. 20 and 21 illustrate the outer appearances of
table illumination devices to which the light-emitting
device 1 or 2 according to the foregoing embodiment is
applied. In the illumination devices, for example, an
44
illumination unit 843 is mounted on a post 842 installed in
a base 841. The illumination unit 843 is configured by any
of the light-emitting devices 1 and 2 according to the
foregoing first and second embodiments. The illumination
unit 843 can be formed in any shape such as a cylindrical
shape illustrated in Fig. 20 or a curved surface shape
illustrated in Fig. 21 by curving a light guide plate 20 in
a curved shape.
Fig. 22 illustrates the outer appearance of an indoor
illumination device to which the light-emitting device 1 or
2 according to the foregoing embodiment is applied. The
illumination device includes, for example, an illumination
unit 844 configured by any of the light-emitting devices 1
and 2 according to the foregoing first and second
embodiments. An appropriate number of illumination units
844 are disposed at appropriate intervals on a ceiling 850A
of a building. The illumination unit 844 can be installed
in any place such as a wall 850B or a floor (not
illustrated) according to uses, as well as the ceiling 850A.
In the illumination devices, illumination is realized
by light from the light-emitting device 1. Here, since the
light-emitting device 1 or 2 in which the color regularity
in the plane is improved, as described in the first
embodiment, is included, illumination quality is improved.
45
Experiment Examples
Experiment Example 1-1
A sample of the light-emitting device 1 according to
the foregoing first embodiment was manufactured. Here, 160
light sources 10 (16 light sources at pitches of 41 mm in
the X direction and 10 light sources at pitches of 36 mm in
the Y direction) were disposed on the reflection substrate
40 with a size of 32 inches. Here, the light reflection
member 60 was not disposed. The distance L1 between the
light source 10 and the wavelength conversion unit 20 was
set to 6 mm, the distance L4 between the front surface 40S
and the rear surface 30S is 30 mm, and the angle 1 was set
to 67.5 (an angle at which the intensity of the light from
the light sources 10 is 38.2%), and the radius R1 was set to
14.5 mm.
Experiment Example 1-2
A sample of the light-emitting device 1 having the same
configuration as that of Experiment Example 1-1 except that
the angle 1 was set to 52.4 (an angle at which the
intensity of the light from the light sources 10 is 61.0%),
and the radius R1 was set to 7.8 mm was manufactured.
Experiment Example 1-3
A sample of the light-emitting device 1 having the same
46
configuration as that of Experiment Example 1-1 except that
the angle 1 was set to 56.9 (an angle at which the
intensity of the light from the light sources 10 is 54.6%),
and the radius R1 was set to 9.2 mm was manufactured.
Experiment Example 1-4
A sample of the light-emitting device having the same
configuration as that of Experiment Example 1-1 except that
a sheet-shaped wavelength conversion unit was disposed
across the entire screen instead of the wavelength
conversion units 20 was manufactured.
In the samples of Experiment Examples 1-1 to 1-4,
tristimulus values X, Y, and Z of XYZ display systems
observed in the region immediately above any one of the
lightened light sources 10 were measured. The results are
shown in Figs. 23A to 23D. In Figs. 23A to 23D, the
horizontal axis represents a position on which the central
position (the position of the optical axis) of the light
source 10 on the XY plane is centered and the vertical axis
represents the normalized intensity of the tristimulus
values X, Y, and Z.
In Experiment Examples 1-4, a variation in the
distributions of the color components of the tristimulus
values X, Y, and Z occurred away from the central position
of the light source 10, and a tendency to exhibit yellow
47
gradually was shown (see Fig. 23D). On the other hand, in
Experiment Example 1-1, the distribution of the color
components gathered, and the variation in the distributions
considerably decreased (see Fig. 23A). In Experiments 1-2,
small peaks on both sides neighboring a main peak were
observed in the distributions of the X and Y components (see
Fig. 23B). The small peaks are considered to occur since
the contours of the direct upper portions 21 were projected
to the optical sheet 30. Further, in Experiment Examples 1-
3, it was confirmed that the intensity of the small peaks
observed on both sides neighboring to the main peak was
suppressed to be small compared to Experiment Example 2 (see
Fig. 23C). Accordingly, it was confirmed that it was
preferable to dispose the direct upper portion 21 at the
position at which the condition expression (1) is satisfied.
Next, Cx and Cy distributions in the central region of
the light emission surface when all of the light sources 10
are turned on were measured for the samples of Experiment
Examples 1-1 and 1-4 described above. The results are
illustrated in Figs. 24A and 24B. In Figs. 24A and 24B, the
left side shows the Cx distribution and the right side shows
the Cy distribution. Here, the measurement was performed
for a surrounding region of 137.4 mm in the vicinity of the
center of the light emission surface.
In Experiment Example 1-1, it was observed that both of
48
the Cx distribution and the Cy distribution were flatter
than those of Experiment Example 1-4.
Likewise, the Cx and Cy distributions ware measured in
an end region of the light emission surface for the samples
of Experiment Examples 1-1 to 1-4 described above. The
results are illustrated in Figs. 25A to 25D. In Figs. 25A
to 25D, the left side shows the Cx distribution and the
right side shows the Cy distribution. Here, the measurement
was performed for a surrounding region of 137.4 mm in the
vicinity of the end region of the light emission surface.
As illustrated in Figs. 25A to 25D, it was observed
that both of the Cx distribution and the Cy distribution
were the flattest in Experiment Example 1-1. In Experiment
Examples 1-2 and 1-3, a steep change was alleviated in both
of the Cx distribution and the Cy distribution compared to
Experiment Example 1-4, and thus the flatness was known to
be improved.
Experiment Example 2-1
A sample of the light-emitting device 1 having the same
configuration as that of Experiment Example 1-1 except that
the light reflection member 60 was further disposed was
manufactured. Here, 60 light sources 10 (10 light sources
at pitches of 66 mm in the X direction and 6 light sources
at pitches of 60 mm in the Y direction) were disposed on the
49
reflection substrate 40 with a size of 32 inches. Further,
the distance L5 (see Fig. 2B) between the light source 10
and the light reflection member 60 was set to 6.5 mm, Tan-
1(R2/L2) was set to 21.4 < 27, and the radius R2 was set to
9.2 mm.
Experiment Example 2-2
A sample of the light-emitting device 1 having the same
configuration as that of Experiment Example 2-1 except that
Tan-1(R2/L2) was set to 27.1 < 27, and the radius R2 was
set to 12.0 mm was manufactured.
Experiment Example 2-3
A sample of the light-emitting device 1 having the same
configuration as that of Experiment Example 2-1 except that
Tan-1(R2/L2) was set to 21.4 < 27, and the radius R1 was
set to 9.2 mm was manufactured.
Experiment Example 2-4
A sample of the light-emitting device 1 having the same
configuration as that of Experiment Example 2-1 except that
Tan-1(R2/L2) was set to 24.3 < 27, and the radius R2 was
set to 10.6 mm was manufactured.
Experiment Example 2-5
50
A sample of the light-emitting device having the same
configuration as that of Experiment Example 2-1 except that
a sheet-shaped wavelength conversion unit was disposed
across the entire screen, instead of the wavelength
conversion units 20 was manufactured.
In the samples of Experiment Examples 2-1 to 2-5, the
distribution of the luminance Y components of XYZ display
systems observed in the region immediate above any one of
the lightened light sources 10 were measured. The results
are shown in Fig. 26. In Fig. 26, the horizontal axis
represents a position on which the central position (the
position of the optical axis) of the light source 10 on the
XY plane is centered and the vertical axis represents the
normalized luminance of the Y component.
In Experiment Examples 2-1 and 2-4, it was confirmed
that steepness in the vicinity of the central position of
the light source 10 was alleviated in comparison to
Experiment Example 1-4. In Experiment Examples 2-2 and 2-3,
steepness in the vicinity of the central position of the
light source 10 was alleviated, but deterioration in the
flatness was shown. From this result, it was confirmed that
it is preferable to dispose the light reflection member 60
at the position at which the condition expression (2) is
satisfied.
Next, a luminance distribution in the central region of
51
the light emission surface when all of the light sources 10
are turned on was measured for the samples of Experiment
Examples 2-1 to 2-5 described above. The results are
illustrated in Figs. 27A to 27E. Here, the measurement was
performed for a surrounding region of 137.4 mm in the
vicinity of the center of the light emission surface.
In Experiment Examples 2-1 and 2-4, it was observed
that the luminance distribution was flatter than that of
Experiment Example 2-5. In Experiment Examples 2-2 and 2-3,
the fatter luminance distribution was known to be obtained
than Experiment Example 2-5.
Experiment Example 3-1
A sample (see Fig. 28A) of the light-emitting device 3
according to the foregoing third embodiment was
manufactured. Here, the planar shapes of the direct upper
portion 21 of the wavelength conversion unit 20 and the
light reflection member 60 were set to, for example,
octagonal shapes illustrated in Fig. 2A. As illustrated in
Figs. 28A, the width of the direct upper portion 21 was set
to 23.0 mm and the width of the light reflection member 60
was set to 17.5 mm. In the light-shielding member 70, an
interval between upper ends 71TS at which the inner surfaces
71S and the top surfaces 71T intersect was set to 10.2 mm.
The height (a distance between the front surface 40S and the
52
top surface 71T) of the wall portion 71 was set to 2.5 mm
and the distance between the light emission point Z0 of the
light source 10 and the direct upper portion 21 of the
wavelength conversion unit 20 was set to 5 mm. The distance
L4 (not illustrated in Fig. 28A) between the front surface
40S and the rear surface 30S was set to 30 mm. In a sample
of Experiment Example 3-1, as illustrated in Fig. 28A, a
part of the wall portion 71 was set to reach the straight
line LB1. That is, all of the light from the light source
10 was set to be incident on the direct upper portion 21 or
the wall portion 71.
Experiment Example 3-2
A sample of the light-emitting device 3 having the same
configuration as that of Experiment Example 3-1 except that
the interval between the upper ends 71TS was set to 19.7 mm
in the light-shielding member 70 and a part of the light
from the light source 10 was oriented directly from a gap
between the direct upper portion 21 and the wall portion 71
to the optical sheet 30 was manufactured (see Fig. 28B).
Experiment Example 3-3
A sample of the light-emitting device 3 having the same
configuration as that of Experiment Example 3-1 except that
the light-shielding member 70 was not installed was
53
manufactured (see Fig. 28C).
In the samples of Experiment Examples 3-1 to 3-5,
tristimulus values X, Y, and Z of XYZ display systems
observed in the region immediate above any one of the
lightened light sources 10 were measured. The results are
shown in Figs. 29A to 29C. In Figs. 29A to 29C, the
horizontal axis represents a position on which the central
position (the position of the optical axis) of the light
source 10 on the XY plane is centered and the vertical axis
represents the normalized intensity of the tristimulus
values X, Y, and Z.
As illustrated in 29A to 29C, in Experiment Examples 3-
1 and 3-2 in which the light-shielding member 70 is
installed, it was known that a variation (luminance
irregularity) of the stimulus value Z (blue component light)
was mainly improved, compared to Experiment Example 3-3 (see
Fig. 29C) in which the light-shielding member 70 is not
present. In particular, in Experiment Example 3-1 (see Fig.
29A), of the light from the light source 10, light oriented
directly from the circumference of the direct upper portion
21 to the optical sheet 30 without being blocked by the wall
portion 71 does not occur due to the structure. Therefore,
compared to Experiment Example 3-2 (see Fig. 29B), in
Experiment Example 3-1, the result was obtained in which the
distributions of the color components of the tristimulus
54
values X, Y, and Z were further improved and the
distributions of the color components of the tristimulus
values X, Y, and Z were almost identical to each other (see
Fig. 29A). In this way, it was confirmed that, in
particular, a variation in the stimulus value Z (blue
component light) was sufficiently suppressed by disposing
the light-shielding member 70 to surround the light source
10.
The disclosure has been described above exemplifying
the embodiments, but embodiments of the present disclosure
are not limited to the embodiments and various modifications
can be made. For example, the materials, thickness, and the
like of the layers described in the foregoing embodiments
are not limited, but the layers have other materials and
thicknesses.
For example, in the foregoing embodiments, the case in
which the light source 10 is an LED has been described, but
the light source 10 may be configured as a semiconductor
laser or the like.
The planar shapes of the direct upper portion 21 of the
wavelength conversion unit 20 and the light reflection
member 60 have been set to the octagonal shapes, but an
embodiment of the present technology is not limited thereto.
For example, as illustrated in Figs. 30A to 30C, the planar
shapes may be tetragonal, hexagonal, or circular shapes. In
55
this case, the planar shapes of all of the direct upper
portions 21 and the light reflection members 60 may be the
same shape, or several portions or members may be different
shapes. The direct upper portion 21 of the wavelength
conversion unit 20 or the light reflection member 60 is not
limited to the film shape, but may have a stereoscopic
shape. For example, a dome shape illustrated in Fig. 31A
may be used. In this case, as illustrated in Fig. 31B, for
example, the connection portion 22 may be placed directly on
the front surface 40S of the reflection substrate 40.
Further, as illustrated in Fig. 32, in the wavelength
conversion units 20, for example, the plurality of direct
upper portions 21 may be joined to the lower surface of one
connection portion 22.
For example, the configurations of the light-emitting
devices 1 and 2 and the display device 101 (television
device) have been described specifically in the foregoing
embodiments. However, all of the constituent elements may
not be included and other constituent elements may be
included.
In the foregoing third embodiment, the contour shape of
the plane of the wall portion 71 of the light-shielding
member 70 has been the circular shape, but another shape may
be used. For example, a polygonal shape such as an
octagonal shape may be used.
56
The advantages described in the present specification
are merely exemplary but are not limited to the description,
and other advantages can be obtained. Embodiments of the
present technology can be configured as follows.
(1)
A light-emitting device includes: a plurality of light
sources configured to be disposed on a substrate; a light
diffusion member configured to commonly cover the plurality
of light sources; and a plurality of wavelength conversion
members configured to be disposed between the light sources
and the light diffusion member in a thickness direction and
disposed in regions corresponding to the plurality of light
sources in a plane, respectively, and configured to convert
light with a first wavelength from the light sources into
light with a second wavelength.
(2)
The light-emitting device described in the foregoing
(1) may further include light reflection members configured
to be disposed between the wavelength conversion members and
the light diffusion members and disposed in regions
corresponding to the plurality of light sources in the
plane, respectively, and configured to reflect the light
transmitted through the wavelength conversion members.
(3)
The light-emitting device described in the foregoing
57
(1) or (2) may further include a first connection member
configured to connect two or more of the wavelength
conversion members.
(4)
In the light-emitting device described in the foregoing
(3), the wavelength conversion member and the first
connection member may be an integrated object formed of the
same material.
(5)
In the light-emitting device described in the foregoing
(4), a width of the first connection member may be narrower
than a width of the wavelength conversion member.
(6)
In the light-emitting device described in any one of
the foregoing (1) to (5), a plurality of wavelength
conversion units including the plurality of wavelength
conversion members arranged in a first direction and first
connection members connecting the plurality of wavelength
conversion members arranged in the first direction to each
other may be disposed in a second direction.
(7)
In the light-emitting device described in any one of
the foregoing (1) to (6), an interval between the light
source and the wavelength conversion member may be shorter
than an interval between the light diffusion member and the
58
wavelength conversion member in the thickness direction.
(8)
In the light-emitting device described in any one of
the foregoing (1) to (7), a central point of the wavelength
conversion member may be identical to an optical axis of the
light source in an in-plane direction and satisfy a
condition expression (1) below:
|1| < Tan-1(R1/L1) ... (1)
where 1 is an angle at which emission intensity of the
light source is 60% of the maximum peak (where an optical
axis direction is assumed to be 0), R1 is a median value of
a circumradius and an inradius in the wavelength conversion
member, and L1 is a distance between the light source and
the wavelength conversion member in the thickness direction.
(9)
In the light-emitting device described in the foregoing
(2), a central point of the light reflection member may be
identical to an optical axis of the light source in an inplane
direction and satisfy a condition expression (2) and a
condition expression (3) below:
Tan-1(R2/L2) < 27 ... (2); and
R2 < R1 ... (3),
where R2 is a median value of a circumradius and an inradius
in the light reflection member, and L2 is a distance between
the light reflection member and the light diffusion member
59
in the thickness direction.
(10)
In the light-emitting device described in any one of
the foregoing (1) to (9), the wavelength conversion member
may include a quantum dot.
(11)
The light-emitting device described in any one of the
foregoing (1) to (10) may further include a plurality of
light-shielding members configured to include a wall portion
erected on the substrate to surround the light source in a
plane intersecting an optical axis of the light source.
(12)
In the light-emitting device described in the foregoing
(11), the wavelength conversion member may be mutually
separated from the light-shielding member.
(13)
In the light-emitting device described in the foregoing
(11) or (12), a part of the light-shielding member may reach
a straight line joining the light source and an end of the
wavelength conversion member.
(14)
The light-emitting device described in any one of the
foregoing (11) to (13) may further include a reflection
sheet configured to be disposed on the substrate. A part of
the reflection sheet may form the light-shielding member.
60
(15)
The light-emitting device described in any one of the
foregoing (11) to (14) may further include a second
connection member configured to connect two or more of the
light-shielding members.
(16)
The light-emitting device described in the foregoing
(15) may further include a first connection member
configured to connect two or more of the wavelength
conversion members. A clip gripping the first connection
member may be installed in the second connection member.
(17)
A light-emitting device includes: a plurality of light
sources configured to be disposed on a substrate; a light
diffusion member configured to commonly cover the plurality
of light sources; and a plurality of wavelength conversion
members configured to be disposed between the light sources
and the light diffusion member in a thickness direction and
have openings or notches in regions other than regions
corresponding to the plurality of light sources in a plane,
respectively, and configured to convert light with a first
wavelength from the light sources into light with a second
wavelength.
(18)
A display device includes: a liquid crystal panel; and
61
a surface light-emitting device on a rear surface side of
the liquid crystal panel. The light-emitting device may
include a plurality of light sources configured to be
disposed on a substrate, a light diffusion member configured
to commonly cover the plurality of light sources, and a
plurality of wavelength conversion members configured to be
disposed between the light sources and the light diffusion
member in a thickness direction and disposed in regions
corresponding to the plurality of light sources in a plane,
respectively, and configured to convert light with a first
wavelength from the light sources into light with a second
wavelength.
(19)
An illumination device includes a light-emitting
device. The light-emitting device includes a plurality of
light sources configured to be disposed on a substrate, a
light diffusion member configured to commonly cover the
plurality of light sources, and a plurality of wavelength
conversion members configured to be disposed between the
light sources and the light diffusion member in a thickness
direction and disposed in regions corresponding to the
plurality of light sources in a plane, respectively, and
configured to convert light with a first wavelength from the
light sources into light with a second wavelength.
It should be understood by those skilled in the art
62
that various modifications, combinations, sub-combinations
and alterations may occur depending on design requirements
and other factors insofar as they are within the scope of
the appended claims or the equivalents thereof.
The present disclosure claims the benefit of Japanese
Priority Patent Application JP 2014-004434 filed January 14,
2014, and Japanese Priority Patent Application JP 2014-
121159 filed June 12, 2014, the entire contents of each of
which are incorporated herein by reference.
In so far as the embodiments of the disclosure
described above are implemented, at least in part, using
software-controlled data processing apparatus, it will be
appreciated that a computer program providing such software
control and a transmission, storage or other medium by which
such a computer program is provided are envisaged as aspects
of the present disclosure.
63
WE CLAIM:
1. A light-emitting device comprising:
a plurality of light sources configured to be disposed
on a substrate;
a light diffusion member configured to commonly cover
the plurality of light sources; and
a plurality of wavelength conversion members configured
to be disposed between the light sources and the light
diffusion member in a thickness direction and disposed in
regions corresponding to the plurality of light sources in a
plane, respectively, and configured to convert light with a
first wavelength from the light sources into light with a
second wavelength.
2. The light-emitting device as claimed in claim 1,
further comprising:
light reflection members configured to be disposed
between the wavelength conversion members and the light
diffusion members and disposed in regions corresponding to
the plurality of light sources in the plane, respectively,
and configured to reflect the light transmitted through the
wavelength conversion members.
3. The light-emitting device as claimed in claim 1,
64
further comprising:
a first connection member configured to connect two or
more of the wavelength conversion members.
4. The light-emitting device as claimed in claim 3,
wherein the wavelength conversion member and the first
connection member are an integrated object formed of the
same material.
5. The light-emitting device as claimed in claim 4,
wherein a width of the first connection member is narrower
than a width of the wavelength conversion member.
6. The light-emitting device as claimed in claim 1,
wherein a plurality of wavelength conversion units including
the plurality of wavelength conversion members arranged in a
first direction and first connection members connecting the
plurality of wavelength conversion members arranged in the
first direction to each other are disposed in a second
direction.
7. The light-emitting device as claimed in claim 1,
wherein an interval between the light source and the
wavelength conversion member is shorter than an interval
between the light diffusion member and the wavelength
65
conversion member in the thickness direction.
8. The light-emitting device as claimed in claim 1,
wherein a central point of the wavelength conversion member
is identical to an optical axis of the light source in an
in-plane direction and satisfies a condition expression (1)
below:
|1| < Tan-1(R1/L1) ... (1)
where 1 is an angle at which emission intensity of the
light source is 60% of the maximum peak (where an optical
axis direction is assumed to be 0), R1 is a median value of
a circumradius and an inradius in the wavelength conversion
member, and L1 is a distance between the light source and
the wavelength conversion member in the thickness direction.
9. The light-emitting device as claimed in claim 2,
wherein a central point of the light reflection member is
identical to an optical axis of the light source in an inplane
direction and satisfies a condition expression (2) and
a condition expression (3) below:
Tan-1(R2/L2) < 27 ... (2); and
R2 < R1 ... (3),
where R2 is a median value of a circumradius and an inradius
in the light reflection member, and L2 is a distance between
the light reflection member and the light diffusion member
66
in the thickness direction.
10. The light-emitting device as claimed in claim 1,
wherein the wavelength conversion member includes a quantum
dot.
11. The light-emitting device as claimed in claim 1,
further comprising:
a plurality of light-shielding members configured to
include a wall portion erected on the substrate to surround
the light source in a plane intersecting an optical axis of
the light source.
12. The light-emitting device as claimed in claim 11,
wherein the wavelength conversion member is mutually
separated from the light-shielding member.
13. The light-emitting device as claimed in claim 11,
wherein a part of the light-shielding member reaches a
straight line joining the light source and an end of the
wavelength conversion member.
14. The light-emitting device as claimed in claim 11,
further comprising:
a reflection sheet configured to be disposed on the
67
substrate,
wherein a part of the reflection sheet forms the lightshielding
member.
15. The light-emitting device as claimed in claim 11,
further comprising:
a second connection member configured to connect two or
more of the light-shielding members.
16. The light-emitting device as claimed in claim 15,
further comprising:
a first connection member configured to connect two or
more of the wavelength conversion members,
wherein a clip gripping the first connection member is
installed in the second connection member.
17. A light-emitting device comprising:
a plurality of light sources configured to be disposed
on a substrate;
a light diffusion member configured to commonly cover
the plurality of light sources; and
a plurality of wavelength conversion members configured
to be disposed between the light sources and the light
diffusion member in a thickness direction and have openings
or notches in regions other than regions corresponding to
68
the plurality of light sources in a plane, respectively, and
configured to convert light with a first wavelength from the
light sources into light with a second wavelength.
18. A display device comprising:
a liquid crystal panel; and
a surface light-emitting device on a rear surface side
of the liquid crystal panel,
wherein the light-emitting device includes
a plurality of light sources configured to be
disposed on a substrate,
a light diffusion member configured to commonly
cover the plurality of light sources, and
a plurality of wavelength conversion members
configured to be disposed between the light sources and the
light diffusion member in a thickness direction and disposed
in regions corresponding to the plurality of light sources
in a plane, respectively, and configured to convert light
with a first wavelength from the light sources into light
with a second wavelength.
19. An illumination device comprising:
a light-emitting device,
wherein the light-emitting device includes
a plurality of light sources configured to be
69
disposed on a substrate,
a light diffusion member configured to commonly
cover the plurality of light sources, and
a plurality of wavelength conversion members
configured to be disposed between the light sources and the
light diffusion member in a thickness direction and disposed
in regions corresponding to the plurality of light sources
in a plane, respectively, and configured to convert light
with a first wavelength from the light sources into light
with a second wavelength.