[Designation of Document] Description
[Title of the Invention] PROJECTOR
[Technical Field]
[OOOl]
The present invention relates to a projector.
[Background Art]
[0002]
A projector using a laser light source has
advantages, such as reduction in the size of the device,
excellent color reproducibility, instantaneous lighting,
and long life time of the llght source. In general, laser
light emitted from the laser light source is coherent
light. For this reason, in this type of projector, a spot
pattern, called speckle noise, caused by interference of
laser light may be visually recognized on a screen.
Accordingly, display quality is significantly degraded.
[0003]
In the projector of the related art using the laser
light source, a countermeasure for suppressing degradation
of display quality due to speckle noise is used. PTL 1
discloses a projection display device in which an entrance
pupil image of a projection lens is greater than an exit
pupil diameter of an illumination optical system, and
which includes pupil matching means for rotationally
moving the exit pupil image of the illumination optical
system in the entrance pupil of the projection lens. NPL
1 describes an explanation relating to a speckle
phenomenon, a speckle elimination method, and the like.
[Citation List]
[Patent Literature]
[0004]
[PTL 11 JP-A-2009-216843
[0005]
[NPL 11 Kazuo, KURODA, et a1 17, "Research Report
of 2009 Ubiquitous Laser Display", Japan Machinery
Federation, Optoelectronics Industry and Technology
Development Association, March, 2010
[Summary of Invention]
[Technical Problem]
[0006]
In the projection display device of PTL 1, as the
pupil matchlng means, a transparent plate which has a
plurality of minute wedge-shaped portions and a motor
which rotates the transparent plate are provided. Since
the pupil matching means rotationally moves the exit pupil
image of the illumination optical system, it is necessary
to increase the size of an imaging lens or a projection
lens disposed at a subsequent stage of the pupil matching
means. As a result, according to the projection display
device, there is a problem in that the device increases in
size due to a need for a space where the pupil matching
means is disposed and an increase in the size of the
imaging lens or the projection lens.
[0007]
NPL 1 describes a prediction method of a speckle.
This prediction method assumes that a pupil image has
uniform illumination. However, in general, the pupil
image of the projector has an illumination distribution.
For this reason, it is not possible to use the prediction
method of NPL 1 practically.
[0008]
An aspect of the invention is to solve the problems
described above and an object thereof is to provide a
projector capable of reliably reducing speckle noise
without causing an increase in the size of the device.
[Solution to Problem]
[0009]
A projector according to a first aspect of the
invention lncludes a laser light source device, a light
diffusion device, a light modulation device, and a
projection optical system. The laser light source device
includes a first laser light source which emits red laser
light, the light diffusion device includes a first light
diffusion element which is provided on the optical path of
the red laser light, and a first drive device which moves
a position where the red laser light is incident on the
first light diffusion element, the light modulation device
includes a first light modulation element which is
provided on the optical path of light emitted from the
first light diffusion element, light emitted from the
first light modulation element is incident on the
projection optical system, and when the center coordinates
of an illumination distribution of the red laser light in
an exit pupil of the projection optical system are x = 0
and y = 0, normalized illumination at each coordinate is
P(x,y), and a calculation range of integration is r (rnrn),
EP determined from Expression (1) is EP > 35.
[ OOlO]
[OOll]
The inventors have found that, when the exit pupil
image of the projection optical system has an illumination
distribution, there is a correlation between evaluation
with EP represented by Expression (1) as an index and
sensitive evaluation of speckle noise. The inventors have
found that, as a result of an experiment, speckle contrast
(hereinafter, abbreviated as SC) as an Index of general
speckle noise and EP have a correlation, and the degree of
speckle noise can be predicted with the magnitude of EP.
Specifically, when the value of EP is small, speckle noise
is easily recognized, and when the value of EP is great,
speckle noise is not easily recognized.
[0012]
With the projector according to the first aspect of
the invention, since the value of EP when red laser light
is used satisfies EP > 35, it is possible to reduce
speckle noise to the degree to be recognizable but not
offensive to an observer. The experiment result showing
the grounds for EP > 35 will be described below. In this
way, with the projector according to the first aspect of
the invention, it is possible to reduce speckle noise by
adjusting the illumination distribution of the exit pupil
image of the projection optical system, and it is not
necessary to add a member, such as a rotation plate. For
this reason, it is possible to provide a projector capable
of reliably reducing speckle noise without causing an
increase in the size of the device.
[0013]
In the projector according to the first aspect of
the invention, it is preferable that EP determined based
on the illumination distribution of the red laser light is
EP > 51.
If the value of EP when the red laser light is used
satisfies EP 2 51, it is possible to reduce speckle noise
to the degree to be hardly recognizable by the observer.
The grounds for EP t 51 will be described below.
[0014]
In the projector according to the first aspect of
the invention, the laser light source device may include a
second laser light source which emits green laser light,
the light diffusion device may include a second light
diffusion element which is provided on the optical path of
the green laser light, and a second drive device which
moves a position where the green laser light is incident
on the second light diffusion element, the light
modulation device may include a second light modulation
element which is provided on the optical path of light
emitted from the second light diffusion element, and light
emitted from the second light modulation element may be
incident on the projection optical system. In this case,
it is preferable that, when the center coordinates of an
illumination distribution of the green laser light in the
exit pupil of the projection optical system are x = 0 and
y = 0, normalized illumination at each coordinate is
P ( x , y ) , and a calculation range of integration is r (mm),
EP determined from Expression (1) is EP 2 27.
[0015]
With the projector according to the first aspect of
the invention, since the value of EP when the green laser
light is used satisfies EP 2 27, it is possible to reduce
speckle noise to the degree to be recognizable but not
offensive to the observer. The grounds for EP 2 27 will
be described below.
[0016]
In the projector according to the first aspect of
the invention, it is preferable that EP determined based
on the illumination distribution of the green laser light
is EP 2 38.
If the value of EP when the green laser light is
used satisfies EP t 38, it is possible to reduce speckle
noise to the degree to be hardly recognizable by the
observer. The grounds for EP t 38 will be descr~bed below.
[0017]
In the projector accord~ng to the first aspect of
the invention, the laser light source dev~ce may include a
third laser light source which emits blue laser light, the
llght diffusion device may include a third light diffusion
element which is provided on the optical path of the blue
laser light, and a third drive device whlch moves a
position where the blue laser light is incident on the
thlrd light diffusion element, the light modulation device
may include a third light modulation element which is
provided on the optical path of light emitted from the
third light diffusion element, and light emitted from the
third light modulation element may be incident on the
projection optical system. In this case, it is preferable
that, when the center coordinates of an illumination
distribution of the blue laser light in the exit pupil of
the projection optical system are x = 0 and y = 0,
normalized illumination at each coordinate is P (x, y) , and
a calculation range of integration is r ( m m ) , EP
determined from Expression (1) is EP 2 16.
[0018]
With the projector according to the first aspect of
the invention, since the value of EP when the blue laser
light is used satisfies EP > 16, it is possible to reduce
speckle nolse to the degree to be recognizable but not
offensive to the observer. The grounds for EP 2 16 will
be described below.
[GO191
In the projector according to the first aspect of
the invention, it is preferable that EP determined based
on the illumination distribution of the blue laser light
is EP 2 26.
If the value of EP when the blue laser light is used
satisfies EP 2 26, it is possible to reduce speckle noise
to the degree to be hardly recognizable by the observer.
The grounds for EP > 26 will be described below.
[0020]
A projector according to a second aspect of the
invention includes a laser light source which emits green
laser light, a light diffusion element which is provided
on the optical path of the green laser light, a drive
device which moves a position where the green laser light
is incident on the light diffusion element, a light
modulation element which is provided on the optical path
of light emitted from the light diffusion element, and a
projection optical. system on which light emitted from the
light modulation element is incident. When the center
coordinates of an illumination distribution of the green
laser light in an exit pupil of the projection optical
system are x = 0 and y = 0, normalized illumination at
each coordinate is P(x,y), and a calculation range of
integration is r (mm), EP determined from Expression (1)
is EP 2 27.
[0021]
[0022]
With the projector according to the second aspect of
the invention, since the value of EP when the green laser
light is used sa-tisfies EP 2 27, it is possible to reduce
speckle noise to the degree to be recognizable but not
offensive to the observer. In this way, with the
projector according to the second aspect of the invention,
it is possible to reduce speckle noise by adjusting the
illumination distribution of the exit pupil image of the ,
projection optical system, and it is not necessary to add
a member, such as a rotation plate. For this reason, it
is possible to provide a projector capable of reliably
reducing speckle noise without causing an increase in the
size of the device.
[0023]
In the projector according to the second aspect of
the invention, it is preferable that EP 2 38.
If the value of EP when the green laser light is
used satisfies EP 2 38, it is possible to reduce speckle
nolse to the degree to be hardly recognizable by the
observer.
[0024]
A projector according to a third aspect of the
invention includes a laser light source which emits blue
laser light, a light diffusion element which is provlded
on the optical path of the blue laser light, a drive
device which moves a position where the blue laser light
is incident on the light diffusion element, a light
modulation element which is provided on the optical path
of light emitted from the light diffusion element, and a
projection optical system on which light emitted from the
light modulation element is incident. When the center
coordinates of an illumination distribution of the blue
laser light in an exit pupil of the projection optical
system are x = 0 and y = 0, normalized illumination at
each coordinate is P(x,y), and a calculation range of
integration is r ( m m ) , EP determined from Expression (1)
is EP 2 16.
[0025]
[0026]
With the projector according to the third aspect of
the invention, since the value of EP when the blue laser
light is used satisfies EP > 16, it 1s possible to reduce
speckle noise to the degree to be recognizable but not
offensive to the observer. In this way, with the
projector according to the third aspect of the invention,
it is posslble to reduce speckle noise by adjust~ng the
illumination distribution of the exit pupil image of the
projection optical system, and it is not necessary to add
a member, such as a rotation plate. For this reason, it
is posslble to provlde a projector capable of reliably
reducing speckle noise without causing an increase in the
slze of the device.
[0027]
In the projector according to the third aspect of
the invention, it is preferable that EP 2 26.
If the value of EP when the blue laser llght is used
satisfies EP 2 26, it is possible to reduce speckle noise
to the degree to be hardly recognizable by the observer.
[0028]
A projector according to a fourth aspect of the
invention includes a laser light source device including a
first laser light source which emits red laser light, a
light modulation device including a first light modulation
element which is provlded on the optlcal path of the red
laser light, and a projection optical system on which
llght emitted from the flrst light modulation element is
incident. When the center coordinates of an illumination
distribution of the red laser light in an exit pupil of
the projection optical system are x = 0 and y = 0,
normalized illumination at each coordinate is P(x,y), and
a calculation range of integration is r (mm), EP
determined from Expression (1) is EP 2 79.
[0029]
[0030]
With the projector according to the fourth aspect of
the invention, since the value of EP when the red laser
light is used satisfies EP 2 79, it is. possible to reduce
speckle noise to the degree to be recognizable but not
offensive to the observer. In this way, with the
projector according to the fourth aspect of the invention,
it is possible to reduce speckle noise by adjusting the
illumination distribution of the exit pupil image of the
projection optical system, and it is not necessary to add
a member, such as a rotation plate. For this reason, it
is possible to provide a projector capable of reliably
reducing speckle noise without causing an increase in the
size of the device.
[0031]
In the projector according to the fourth aspect of
the invention, it is preferable that EP determined based
on the illumination distribution of the red laser light is
EP 2 119.
If the value of EP when the red laser light is used
satisfies EP > 119, it is possible to reduce speckle noise
to the degree to be hardly recognizable by the observer.
In the projector according to the fourth aspect of
the invention, the laser light source device may further
include a second laser light source which emits green
laser light, the light modulation device' may further
include a second light modulation element which is
provided on the optical path of the green laser light, and
light emitted from the second light modulation element may
be incident on the projection optical system. In this
case, it is preferable that, when the center coordinates
of an ~llumination distribution of the green laser light
in the exit pupil of the projection optical system are x =
0 and y = 0, normalized illumination at each coordinate is
P(x,y) ,, and a calculation range of integration is r ( m m ) ,
EP determined from Expression (1) is EP > 65.
LO0331
With the projector according to the fourth aspect of
the invention, since the value of EP when the green laser
light is used satisfies EP > 65, it is possible to reduce
speckle noise to the degree to be recognizable but not
offensive to the observer.
[ 0 0 3 4 ]
In the projector according to the fourth aspect of
the invention, it is preferable that EP determined based
on the illumination distribution of the green laser light
is EP 2 93.
If the value of EP when the green laser light is
used satisfies EP > 93, lt is possible to reduce speckle
noise to the degree to be hardly recognizable by the
observer.
[0035]
In the prolector according to the fourth aspect of
the invention, the laser llght source device may further
include a third laser light source which emits blue laser
light, the light modulatlon device may further include a
third light modulatlon element which is provided on the
optical path of the blue laser light, and light emitted
from the third light modulation element may be incident on
the projection optical system. In this case, it is
preferable that, when the center coordinates of an
illumination distribution of the blue laser light in the
exit pupil of the projection optical system are x = 0 and
y = 0, normalized illumination at each coordinate is
P (x, y) , and a calculation range. of integration is r (mm) ,
EP determined from Expression (1) is EP 2 45.
[0036]
With the projector according to the fourth aspect of
the invention, since the value of EP when the blue laser
light is used satisfies EP 2 45, it is possible to reduce
speckle noise to the degree to be recognizable but not
offensive to the observer.
[0037]
In the projector according to the fourth aspect of
the invention, it is preferable that EP determined based
on the illumination distribution of the blue laser light
1s EP 2 59.
If the value of EP when the blue laser llght 1s used
satisfies EP 2 59, it is possible to reduce speckle noise
to the degree to be hardly recognizable by the observer.
[0038]
A projector according to a fifth aspect of the
invention includes a laser light source which emits green
laser llght, a llght modulation element which is provided
on the optical path of the green laser light, and a
projection optical system on which light emitted from the
light modulation element is incident. When the center
coordinates of an illumination distribution of the green
laser light in an exit pupil of the projection optical
system are x = 0 and y = 0, normalized illumination at
each coordinate is P(x, y), and a calculation range of
integration is r (mm), EP determined from Expression (1)
is EP 2 65.
[0039]
[0040]
With the projector according to the fifth aspect of
the invention, since the value of EP when the green laser
light is used satisfies EP > 65, it is possible to reduce
speckle noise to the degree to be recognizable but not
offensive to the observer. In this way, with the
projector according to the fifth aspect of the invention,
it is possible to reduce speckle noise by adjusting the
illumination distribution of the exit pupil image of the
projection optical system, and it is not necessary to add
a member, such as a rotation plate. For this reason, it
1s possible to provide a projector capable of reliably
reducing speckle noise wlthout causing an increase in the
size of the device.
[0041]
In the projector according to the fifth aspect of
the invention, it is preferable that EP t 93.
If the value of EP when the green laser light is
used satisfies EP 2 93, it is possible to reduce speckle
noise to the degree to be hardly recognizable by the
observer.
[0042]
A projector according to a sixth aspect of the
invention includes a laser light source which emits blue
laser light, a light modulation element which is provided
on the optical path of the blue laser light, and a
projection optical system on which light emitted from the
light modulation element is incident. When the center
coordinates of an illumination distribution of the blue
laser light in an exit pupil of the projection optical
system are x = 0 and y = 0, normalized illumination at
each coordinate is P ( x , y ) , and a calculation range of'
integration is r ( m m ) , EP determined from Expression (1)
is EP 2 45.
[0043]
[0044]
With the projector according to the sixth aspect of
the invention, slnce the value of EP when the blue laser
light is used satisfies EP 2 45, it is possible to reduck
speckle noise to the degree to be recognizable but not
offensive to the observer. In this way, with the
projector according to the sixth aspect of the invention,
it is possible to reduce speckle noise by adjusting the
illumination distribution of the exit pupil image of the
projection optical system, and it is not necessary to add
a member, such as a rotation plate. For this reason, it
is possible to provide a projector capable of reliably
reducing speckle noise without causing an increase in the
size of the device.
[DO451
In the projector according to the slxth aspect of
the invention, it is preferable that EP > 59.
If the value of EP when the green laser light is
used satisfies EP 2 59, it IS possible to reduce speckle
nolse to the degree to be hardly recognizable by the
observer.
[0046]
In the projector according to any one of the first
to sixth aspects of the invention, it is preferable that
the normalized illumination P (x, y) is expressed by
Expression (2).
P (x, y) = illumination (cd/m2) / average illumination
(cd/m2) of the top 0.1% in an illum~nation distribution of
a pupil diameter ... (2)
[0047]
The normallzed illumination is calculated by
Expression (Z), whereby it is possible to obtain an
evaluation result with high accuracy, for example, as a
value in consideration of the distribution of a high
2 0
illumination component in the illumination distribution in
the exit pupil of the projection optical system.
[00481
In the projector according to any one of the first
to sixth aspects of the invention, a value integrated over
a unit time may be used as the normalized illumination
p (x, y) .
With this configuration, even when the illumination
distribution in the exit pupil of the projection optical
system changes over time, it is possible to obtain an
evaluation result with high accuracy.
[0049]
In the projector according to any one of the first
to s~xth aspects of the invention, it is preferable that
the laser light source device is a multimode semiconductor
laser light source.
In the case of the multimode semiconductor laser
light source, for example, since a coherent length is
short and a wavelength width is wide compared to a singlemode
semiconductor laser light source, a semiconductorpumped
solid-state (DPSS) laser, or the like, it is
possible to effectively reduce speckle noise.
[Brief Description of Drawings]
[0050]
[Fig. 11 Fig. 1 is a schematic configuration
diagram showing a projector according to a first
embodiment of the invention.
[Fig. 21 Fig. 2 is a diagram illustrating SC.
[Fig. 31 Fig. 3 is a diagram showing the coordinate
axes of an illumination distribution in a calculation
expression of EP.
[Fig. 41 Fig. 4 is a diagram showing an example of
an illumination distribution.
[Fig. 51 Fig. 5 is a diagram showing an example of
a histogram of illumination.
[Fig. 61 Fig. 6 is a graph showing the relationship
between EP and SC.
[Fig. 71 Fig. 7 is a diagram showing the positional
relationsh~p of a projector, a subject, and a screen in an
example.
[Fig. 81 Fig. 8 is a graph showing the correlation
of EP and SC in a flrst example.
[Fig. 91 Fig. 9 is a graph showlng the correlation
of EP and SC in a second example.
[Fig. 101 Fig. 10 1s a graph showing the
correlation of EP and SC in a third example.
[Fig. 111 Fig. 11 is a schematic configuration
diagram showing a projector according to a second
embodiment of the invention.
[Fig. 121 Fig. 12(A) is a diagram showing a
temporal change of an illumination distribution, and Fig.
12(B) is a diagram showing a state where a temporal change
of an illumination distribution is temporally integrated.
[Description of Embodiments]
[GO511
[First Embodiment]
Hereinafter, a first embodiment of the invention
will be described referring to Figs. 1 to 6.
In this embodiment, an example of a projector using
a laser light source device is shown.
Fig. 1 is a schematic configuration diagram showing
a projector according to the first embodiment of the
invention.
In the following drawings, for ease of visual
recognition of the respective constituent elements', the
constituent elements may be different in scale.
[GO521
As shown in Fig. 1, a projector 1 includes a laser
light source device LSR, an illumination optical system
100R, an illumination optical system 100G, an illumination
optical system 100B, a red liquid crystal light valve
(first light modulation element) 3R, a green liqu~d
crystal light valve (second light rnodulatlon element) 3G,
a blue liquid crystal light valve (third light modulation
element) 3B, a color composition element 4, and a
projection optical system 5.
[0053]
The laser light source device LSR includes at least
one red laser light source (flrst laser light source) 7R,
at least one green laser light source (second laser llght
source) 7G, and at least one blue laser light source
(third laser light source) 7B. Each of the red laser
light source 7R, the green laser light source 7G, and the
blue laser light source 7B is a multimode semiconductor
laser.
[0054]
The illumination optical system 100R includes a
diffraction optical element 8, a superposition optical
system 9, a first light diffusion element lOR, and a first
drive device 11R.
The illumination optical system 100G includes a
diffraction optical element 8, a superposition optical
system 9, a second light diffusion element lOG, and a
second drive device 11G.
The illumination optical system 100B includes a
diffraction optical element 8, a superposition optical
system 9, a third light diffusion element 10B, and a third
drive device 11B.
[0055]
In this embodiment, a light diffusion device
includes the first light diffusion element 10R, the second
light diffusion element 10G, the third light diffusion
element 10B, the first drive device 11R, the second drive
device 11G, and the third drive device 11B. A light
modulation device includes the red liquid crystal light
valve 3R, the green liquid crystal light valve 3G, and the
blue liquid crystal light valve 3B.
[0056]
In the following description, the first llght
diffusion element 10R, the second light diffusion element
10G, and the third llght diffus~on element 10B are
referred to as a light diffusion element 10, and the first
drlve device 11R, the second drive device 11G, and the
third drive device 11B are referred to as a drive devlce
11.
[0057]
A plurality of red laser light sources 7R and the
illumination optical system l0OR corresponding to a
plurality of red laser llght sources 7R constitute a red
light source device 2R. A plurality of green laser light
sources 7G and the illumination optical system l0OG
corresponding to a plurality of green laser light sources
7G constitute a green light source device 2G. A plurality
of blue laser light sources 7B and the illumlnation
optical system l0OB corresponding to a plurality of blue
laser light sources 7B constitute a blue llght source
device 2B.
[0058]
In summary, the projector 1 operates as follows.
Red laser light L, emitted from the red light source
device 2R is incident on the red liquid crystal light
valve 3R and modulated. Similarly, green laser light LG
emitted from the green light source device 2G is incident
on the green liquid crystal light valve 3G and modulated.
Blue laser light Lg emitted from the blue light source
device 2B is incident on the blue liquid crystal light
valve 3B and modulated. Red laser light L, modulated by
the red liquid crystal light valve 3R, green light LG
modulated by the green liquid crystal light valve 3G, and
blue light Lg modulated by the blue liquid crystal light
valve 3B are incident on the color composition element 4
and composed. Light (image light) composed by the color
composition element 4 is projected onto a screen 13 by the
projection optical system 5 on a magnified scale. In this
way, a full-color projection image is displayed.
[0059]
Hereinafter, the respective constituent elements of
the projector 1 will be described.
The red light source device 2R, the green light
source device 2G, and the blue light source device 2B have
the same configuration but are different in emitted light
color. Accordingly, in the following description, only
the red light source device 2R will be described, and
description of the green light source device 2G and the
blue light source device 2B will be omitted.
[0060]
The red llght source device 2R includes a plurality
of red laser light sources 7R. In Fig. 1, although the
red light source device 2R includes three red laser light
sources 7R, the number of red laser light sources 7R is
not particularly limited to three. A plurality of red
laser light sources 7R are arranged not only in a
direction parallel to the paper surface but also in a
direction perpendicular to the paper surface, and may be
arranged in an array as a whole. The same applies to the
green light source device 2G and the blue light source
device 2B. As an example, the red laser light source 7R
emits light in a wavelength region of about 585 nm to 720
nm. The green laser light source 7G ernlts light in a
wavelength region of about 495 nm to 585 nm. The blue
laser light source 7B emits light in a wavelength region
of about 380 nm to 495 nm.
[0061]
Each red laser light source 7R may include a
collimator lens (not shown). When each red laser light
source 7R includes the collimator lens, the emitted red
laser light LR is incident on the collimator lens,
parallelized, and emitted. The same applies to the green
laser light source 7G and the blue laser light source 7B.
[0062]
The red laser light LR emitted from the red laser
light source 7R is incident on the light diffusion element
10. The light diffusion element 10 expands the emission
angle distribution of light emitted from the light
diffusion element 10 with respect to the incidence angle
distribution of light incident on the light diffusion
element 10. The light diffusion element 10 can be
constituted of, for example, a light diffusion plate, such
as frosted glass or a diffusion film, a diffraction
optical element, such as a holographic diffuser, a lens
component, such as a microlens array, or the like.
[0063]
The light diffusion element 10 has a rotation shaft
which passes through the center of the substrate and
extends in a direction normal to the substrate. The
rotation shaft is connected to a motor which is the drive
device 11 of the light diffusion element 10. The
operation of the drive device 11 causes the light
diffusion element 10 to rotate around the rotation shaft.
The light diffusion element 10 is provided to uniformize
the luminous intensity distribution of light projected
onto the screen 13 and to reduce speckle noise. The
rotation of the light diffusion element 10 allows a
momentarily changing spatial distribution of speckle noise
to be superposed with time and speckle noise to be further
reduced.
LOO641
The red laser light L, emitted from the light
diffusion element 10 is incident on the diffraction
optical element 8. The diffraction optical element 8 is
made of a computer generated hologram (CGH). The CGH is,
for example, a surface relief type hologram element in
which minute unevenness designed by a computer is provided
in the surface of a base material made of a light
transmissive material, such as quartz (glass) or synthetic
resin. The diffraction optical element 8 diffracts the
incident red laser light LR, thereby uniformizing the
intensity distribution of the red laser light L, incident
on the red liquid crystal light valve 3R described below
and increasing the use efficiency of the red laser light
LR incident on the red liquid crystal light valve 3R.
Diffracted light emitted from the diffraction optical
element 8 is incident on the superposition optical system
9.
The superposition optical system 9 has at least one
superposition lens. The superposition optical system 9
superposes a plurality of light beams emitted from the
diffraction optical element 8 on a liquid crystal light
valve as a region to be illuminated. Here, an example of
the superposition optical system 9 having two
superposition lenses of a first superposition lens 9A and
a second superposition lens 9B is shown. A plurality of
light beams of the red laser light LR emitted from the
diffraction optical element 8 is incident on the red
liquid crystal light valve 3R through the superposition
optical system 9. A plurality of light beams are
superposed on one another on the red liquid crystal light
valve 3R by the superposition optical system 9. With th~s,
the luminance distribution of light illuminating the red
liquid crystal light valve 3R is uniformized, and axis
symmetry around the ray axis is increased.
[0066]
Though not shown, the red liquid crystal light valve
3R includes a liquid crystal panel with a liquid crystal
layer interposed between a pair of glass substrates, a
light incidence side polarizing plate disposed on the
light incident side of the liquid crystal panel, and a
light emission side polarizing plate disposed on the light
emission side of the liquid crystal panel. The mode of
the liquid crystal layer is a TN mode, a VA mode, a
transverse electric field mode, or the like, and is not
particularly limited. The green liquid crystal light
valve 3G and the blue liquid crystal light valve 3B have
the same configuration.
[On671
The color composition element 4 is constituted of a
cross dichroic prism or the like. The cross dichroic
prism has a structure in which four triangular prisms are
laminated with one another. The surface to be laminated
in the triangular prism becomes the inner surface of the
cross dichroic prism. In the inner surface of the cross
dichrolc prism, a mirror surface on which red llght is
reflected and green light is transmitted is orthogonal to
a mirror surface on which blue light is reflected and
green llght is transmitted. The green light incldent on
the cross dichroic prism is transmitted through the mirror
surface and emitted directly. The red light and the blue
light incident on the cross dichroic prism are selectively
reflected on the mirror surface and emitted in the same
direction as the emission direction of the green light.
In this way, the three color light components are
superposed and composed, and the composed color light is
emltted toward the projection optical system 5.
[0068]
In the projector 1 configured as above, as shown in
Fig. 2, when a numerical aperture on a projection side
when llght from the projection optical system 5 is
incident on the screen 13 is NAP, and a numerical aperture
on an observation side when light from the screen 13 is
emitted is NAe, speckle contrast SC is expressed by
Expression (2).
[0069]
[0070]
As will be apparent from Expression (2), when the
observation-side numerical aperture NAe is constant,
speckle contrast SC is determined by the projection-side
numerical aperture NAP. In the projector, the projectionside
numerical aperture NAp is determined by the distance
between the exit pupil of the projection optical system
and the screen and the size of the exit pupil. The
observation-side numerical aperture NAe is determined by
the distance between the observer and the screen and the
size of the pupil of the observer. However, for
calculating speckle contrast SC using Expression (2), it
is assumed that the illumination distribution of the pupil
image in the exit pupil of the projection optical system
is uniform within the range of the projection-side
numerical aperture NAp. However, the actual exit pupil
image of the projector has an illumination distribution
shown in Fig. 4, and illumination is not uniform. For
this reason, the assumption of Expression (2) is not
satisfied, and it is not possible to accurately calculate
speckle contrast SC.
[0071]
Accordingly, the inventors have experimentally
reached an expression of determining an index capable of
evaluating speckle noise with excellent accuracy even if
the exit pupil image has an illumination distribution. As
shown in Fig. 3, the orthogonal axes with the center of an
exlt pupil image Z as the origin 0 of the coordinates are
referred to as the x axis and the y axls. At this time,
normalized illuminat~on at the point of the coordinates
(x, y) 1s represented as P(x, y) . The inventors have
decided to call the index represented by Expression (1) EP
(Effective Pupil).
[0072]
[0073]
The normalized illumination P (x, y) is determined by
Expression (3).
P (x, y) = illumination (cd/m2) / average illumination
(cd/m2) of the top 0.1% in the illumination distribution
of the exit pupil image ... (3)
[0074]
In Expression (I), it is possible to calculate EP
using the normalized illuminat~on, instead of absolute
illumination, without depending on brightness of the exit
pupil image. For calculating the normalized illumination,
the average illumination of the top 0.1% of brightness of
the exit pupil image is used, whereby it is possible to
further increase the accuracy of the calculation result of
EP. The reason is as follows.
LO0751
Speckle noise refers to that the difference between
the levels of illumination is recognized as a speckle by
human eyes. A portion with high illumination causes a
bright interference speckle, and a portion with low
illumination causes a dark interference speckle. Speckle
nolse caused by interference of a portlon wlth high
illumination is easily recognized by the human. That is,
speckle noise is more significantly affected by the
portion with high illumination than the portion with low
illumination.
[0076]
For example, Fig. 5 shows the illumination
distribution of the exit pupil image shown in Fig. 4 by a
histogram. The horizontal axis of the graph represents
illumination, and the vertical axis represents frequency.
In this way, a high illumination component is distributed
at the bottom on the right side of the graph. As the
calculation method of the normalized illumination, for
example, a case where the maximum value of illumination in
the illumination distribution is used as a reference is
considered. However, when a very high illumination
component is included in the illumination distribution due
to the occurrence of spike, or the like, in this
calculation method, an illumination distribution in a high
illumination region is not correctly reflected in the
calculation result of EP. For this reason, it is not
possible to calculate the value of EP optimized for human
eyes. In contrast, the inventors have found from the
experiment result that the value of EP properly reflected
with the illumination distribution in the high
illumination region is obtained by calculating the
normalized illumination with the average illumination of
the top 0.1% of brightness as a reference.
[0077]
The inventors have experimentally generated an exit
pupil image when transmitted through one circular aperture
and an exit pupil image when transmitted through multiple
circular apertures and have obtained the correlation
between SC and EP. The result is shown in Fig. 6. The
horizontal axis in Fig. 6 represents EP, and the vertical
axis represents SC. In this way, even lf the shape of the
exit pupil image is d~fferent, it has been found that
there 1s the correlation between SC and EP indicated by a
broken-line curve. That is, it has been found that SC can
be predicted using EP calculated uslng Expression (1).
[0078]
The inventors have performed sensitive evaluation of
speckle noise by multiple subjects.
In the projector 1 of the first embodiment, a time
superposition effect of speckle noise has been evaluated
by comparing speckle noise when the light diffusion
element 10 is not rotated with speckle noise when the
light diffusion element 10 is rotated. When the light
diffusion element 10 is not rotated, the time
superposition effect of speckle noise is not included, and
when the light diffusion element 10 is rotated, the time
superposition effect of speckle noise is included.
[0079]
As the conditions for evaluation, as shown in Fig. 7,
the distance L between the exit pupil image of the
projector 1 and the screen 13 was set 2 m, and the
distance between a subject M and the screen 13 was set to
2 m. The reason that the distances are set to 2 m is
because it is assumed that the projector 1 is used in a
conference or the like. For the screen 13, a white mat
screen was used.
[0080]
For example, the intensity distribution of the exit
pupil image was adjusted by changing the interval among a
plurality of red laser light components emitted from the
laser light source device LSR with respect to red light.
The intensity distribution of the exit pupil image was
adjusted in a similar manner for other color light
components. In this way, the value of EP was adjusted by
adjusting the intensity distribution of the exit pupil
image.
[0081]
First, red light having a center wavelength of 638
nm was emitted from the projector 1, and sensitive
evaluation of speckle noise was performed. Table 1 and
Table 2 show the result of evaluating how much speckle
noise is obstructive by the eyes of the multiple subjects
when the exit pupil image is changed in various ways.
[0082]
Table 1 shows the calculation result of SC and EP
when the light diffusion element is not rotated and the
result of subjective evaluation of the subjects. Table 2
shows the calculation result of SC and EP when the light
diffusion element is rotated and the result of subjective
evaluation of the subjects. In the column of subjective
evaluation of Table 1 and Table 2, "x" indicates that
speckle noise is offensive to all subjects, "A" indicates
that speckle noise is recognized by about half of the
subjects but not offensive, and "0" indicates that speckle
noise is substantially not recognized by all subjects.
[0083]
[Table 11
[Table 21
[OOSS]
Fig. 8 shows the evaluation results of Table 1 and
Table 2 into a graph. The horizontal axis of the graph
represents EP, and the vertical axis of the graph
represents SC. A lower region of a line indicated by a
broken line corresponds to the regions of "A" and "0" of
Table 1 and Table 2. In this way, it has been understood
that, when SC is equal to or less than a predetermined
value, speckle noise is recognized but not offensive.
[0086]
From the above evaluation results, when SC is equal
to or less than 1.7%, speckle noise is not offensive to
about half of the subjects. At this time, EP was equal to
or greater than 79 when the light diffusion element was
not rotated, and was equal to or greater than 35 when the
light diffusion element was rotated. Furthermore, when SC
is equal to or less than 1.5%, speckle noise is not
recognized by all subjects. At this time, EP was equal to
or greater than 119 when the light diffusion element was
not rotated, and was equal to or greater than 51 when the
light diffusion element was rotated.
[0087]
Next, green light havlng a center wavelength of 520
nm was emitted from the projector 1, and sensitive
evaluation of speckle noise was performed.
[0088]
Table 3 shows the calculation result of SC and EP
when the light diffusion element is not rotated and the
result of subjective evaluation of the subjects. Table 4
shows the calculation result of SC and EP when the light
diffusion element is rotated and the result of subjective
evaluation of the subjects. In the column of subjective
evaluation of Table 3 and Table 4, "xu Indicates that
speckle noise is offensive to all subjects, "A" indicates
that speckle noise is recognized by about half of the
subjects but not offensive, and "0" indicates that speckle
noise is substantially not recognized by all subjects.
[0089]
[Table 31
[0091]
Fig. 9 shows the evaluation results of Table 3 and
Table 4 into a graph. The horizontal axis of the graph
represents EP, and the vertical axis of the graph
represents SC. A lower region of a line indicated by a
broken llne corresponds to the reyions of "A" and "0" of
Table 3 and Table 4. In this way, it has been understood
that, when SC is equal to or less than a predetermzned
value, speckle noise is recognized but not offensive.
[0092]
From the above evaluation results, when SC is equal
[0090]
[Table 41
S C
2.7%
1.8%
1.6%
1.2%
EP
7
2 7
38
93
Subjective
Evaluation
x
A
0
0
to or less than 1.8%, speckle noise is not offensive to
about half of the subjects. At this time, EP was equal to
or greater than 65 when the light diffusion element was
not rotated, and was equal to or greater than 27 when the
light diffusion element was rotated. Furthermore, when SC
is equal to or less than 1.6%, speckle noise is not
recognized by all subjects. At this time, EP was equal to
or greater than 93 when the light diffusion element was
not rotated, and was equal to or greater than 38 when the
light diffusion element was rotated.
[0093]
Next, blue light having a center wavelength of 445
nm was emitted from the projector 1, and sensitive
evaluation of speckle noise was performed.
[0094]
Table 5 shows the calculation result of SC and EP
when the light diffusion element is not rotated and the
result of subjective evaluation of the subjects. Table 6
shows the calculation result of SC and EP when the light
diffusion element is rotated and the result of subjective
evaluation of the subjects. In the column of subjective
evaluation of Table 5 and Table 6, "x" indicates that
speckle noise is offensive to all subjects, "A" indicates
that speckle noise is recognized by about half of the
subjects but not offensive, and "0" indicates that speckle
noise is substantially not recognized by all subjects.
[0095]
[Table 51
[0096]
[Table 61
[0097]
Fig. 10 shows the evaluation results of Table 5 and
Table 6 into a graph. The horizontal axis of the graph
S C
3.5%
3.2%
2.7%
1.9%
1.7%
1.2%
1.1%
EP
2.64
3.44
6
16
2 6
7 8
95.41
Subjective
Evaluat~on
x
x
x
A
0
0
0
represents EP, and the vertical axis of the graph
represents SC. A lower region of a line indicated by a
broken line corresponds to the regions of "A" and "0" of
Table 5 and Table 6. In this way, it has been understood
that, when SC is equal to or less than a predetermined
value, speckle noise 1s recognized but not offensive.
[0098]
From the above evaluation results, when SC is equal
to or less than 1.9, speckle noise is not offensive to
about half of the subjects. At this time, EP was equal to
or greater than 45 when the light dlffusion element was
not rotated, and was equal to or greater than 16 when the
light diffusion element was rotated. Furthermore, when SC
is equal to or less than 1.7%, speckle noise is not
recognized by all subjects. At this time, EP was equal to
or greater than 59 when the light dlffusion element was
not rotated, and was equal to or greater than 26 when the
light diffusion element was rotated.
[0099]
The above evaluation results were revised and
summarlzed in a table as follows.
Even if speckle noise is recognized by human eyes,
if the value of EP is determined such that speckle noise
does not become the level to be not offensive practically,
Table 7 is obtained. More preferably, if the value of EP
is determined such that speckle noise becomes the level to
be not substantially recognizable by human eyes, Table 8
is obtained.
[ OlOO]
[Table 71
[01011
[Table 81
Red (638 nm)
Green (520 nm)
Blue (445 nm)
[0102]
The reason that the target value of EP is different
according to the color (wavelength region) of laser light
is because the size of a speckle depends on a wavelength.
When the wavelength is shorter, the slze of a speckle is
smaller. If a speckle is equal to or smaller than a given
size, the speckle is hardly recognized by human eyes.
Furthermore, since blue l~ght has low sensitivity to human
eyes, speckle noise is hardly recognized -Ln blue light.
For this reason, the target value of EP in blue light is
smaller than the target value of EP in other colors.
Not Rotated
7 9
6 5
4 5
Red (638 nm)
Green (520 nm)
Blue (445 nm)
Rotated
3 5
2 7
16
Not Rotated
119
93
5 9
Rotated
5 1
38
2 6
[@lo31
The target value of EP is set for each color. If
the difference in wavelength between two light rays is
great, the difference is recognized as different colors by
human eyes, and speckle noise is separated and recognized.
In this case, the effect of spatial superposition is not
obtained.
[0104]
With the projector 1 of the first embodiment, lt is
possible to reduce speckle noise by adjusting the
illumination distribution of the exit pupil image of the
projection optical system 5 and to provide a projector
capable of reliably reduclng speckle noise.
[01@5]
[Second Embodiment]
Hereinafter, a second embodiment of the invention
will be described referring to Figs. 11 and 12.
The basic configuration of a projector of the second
embodiment is the same as the first embodiment, and the
configuration of a light source device is different.
Fig. 11 is a schematic configuration diagram showing
a projector according to the second embodiment of the
invention.
In Fig. 11, the constituent elements common to Fig.
1 used in the first embodiment are represented by the same
reference numerals, and detailed description thereof will
not be repeated.
[0106]
As shown in Fig. 11, a projector 21 includes a laser
light source device LSR, an illumination optical system
200R, an illumination optical system 200G, an illumination
optlcal system 200B, a red liquid crystal light valve 3R,
a green liquid crystal light valve 3G, a blue liquid
crystal light valve 3B, a color composition element 4, and
a projection optical system 5.
[0107]
The illumination optical system 200R includes an
optical path conversion element 23, a diffraction optical
element 8, a superposition optical system 9, a first light
diffusion element 10R. and a first drive device 11R.
The illumination optical system 200G includes an
optical path conversion element 23, a diffraction optical
element 8, a superposition optical system 9, a second
light diffusion element 10G, and a second drive device 11G.
The illumination optical system 200B includes an
optical path conversion element 23, a diffraction optical
element 8, a superposition optical system 9, a third light
diffusion element 10B, and a third drive device 1lB.
[0108]
A plurality of red laser light sources 7R and the
illumination optical system 200R corresponding to a
plurality of red laser light sources 7R constitute a red
light source device 22R. A plurality of green laser light
sources 7G and the illumination optical system 200G
corresponding to a plurality of green laser light sources
7G constitute a green light source device 22G. A
plurality of blue laser light sources 7B and the
illumination optical system 200B corresponding to a
plurality of blue laser light sources 7B constitute a blue
light source device 22B.
[0109]
The red light source device 22R includes a plurality
of red laser light sources 7R. In Fig. 11, although only
one red laser light source 7R is shown, a plurality of red
laser light sources 7R are arranged in a direction
perpendicular to the paper surface. In this embodiment,
al-though six red laser light sources 7R are used, the
number of red laser light sources is not particularly
limited to six. The same applies to the green light
source device 22G and the blue light source device 22B.
[0110]
The optical path conversion element 23 is disposed
on the optical path of the red laser light LR emitted from
a plurality of red laser light sources 7R. In this
embodiment, a galvano-mirror is used as the optical path
conversion element 23. The galvano-mirror is a mirror
which rotates around a rotation shaft. The optical path
conversion element 23 is provided with a drive device (not
shown). The optical path conversion element 23 is rotated
within a given angle range by the drive device. According
to the rotation of the optical path conversion element 23,
the incidence angle of the red laser light LR from the red
laser light sources 7R to the optical path conversion
element 23 changes, and the emission direction of the red
laser light L, from the optical path conversion element 23
changes.
[Olll]
At this time, as shown in Fig. 12 (A), six
irradiation spots S corresponding to the arrangement of
the red laser light sources 7R are scanned with time from
one end toward the other end of an exit pupil Pu. In this
way, the exit pupil image changes with time. Accordingly,
in this embodiment, illumination is integrated over the
time to be recognizable as one frame period by the human,
for example, over 1/50 seconds. Fig. 12(B) shows an image
of an illumination distribution B after illumination is
integrated. EP is calculated in the same manner as in
Example 1 with the illumination distribution B as the exit
pupil image. The period to be recognizable as one frame
period by the human corresponds to a unit time in the
appended claims.
[0112]
With the projector 21 of the second embodiment, it
is possible to reduce speckle noise by adjusting the
illumination distribution of the exit pupil image of the
projection optical system 5 and to provide a projector
capable of reliably reducing speckle noise. Furthermore,
a value integrated over a unit time is used as the
normalized Illumination P(x,y), whereby lt is possible to
obtain an evaluation result with high accuracy even when
the illumination distribution in the exit pupil image of
the projection optical system 5 changes with time.
[0113]
The technical scope of the invention is not limited
to the foregoing embodiments, and various alterations can
be made without departing from the spirit of the invention.
For example, in the foregoing embodiments, although
a configuration in which the light diffusion element 10 is
rotated is used in order to superpose speckle noise with
time, a configurat~on in which the light diffus~on element
10 is vibrated, the light diffusion element 10 is
oscillated, or the like may be used.
[0114]
The diffraction optical element 8 may be moved,
instead of moving the light diffusion element 10. In this
case, the light diffusion element 10 may be omitted. When
the light diffusion element 10 is omitted, the light
diffusion device is constituted of the diffraction optical
element 8, and a drive device which moves the diffraction
optical element 8.
[GI151
Furthermore, means for superposing speckle noise
with time is not limited to the above-described means.
[GI161
In the foregoing embodiments, although the light
diffusion device is provided even when speckle noise is
not superposed with time, the light diffusion device may
be omitted. However, in order to uniformize the intensity
distribution of the exit pupil image, it is preferable to
spread light using a light diffusion element or a lens.
[GI171
In the foregoing embodiments, although the light
diffusion element and the drive device are provided In
each of the red laser light source 7R, the green laser
light source 7G, and the blue laser light source 7B, the
invention is not limited thereto. A set of a light
diffusion element and a drive device common to the red
laser light source 7R, the green laser light source 7G,
and the blue laser light source 7B may be provided.
[GI181
In the foregoing embodiments, although the light
modulation device includes the red liquid crystal light
valve 3R, the green liquid crystal light valve 3G, and the
blue liquid crystal light valve 3B, the invention is not
limited thereto. A configuration may be made in which one
liquid crystal light valve modulates red light, green
light, and blue light. Instead of the liquid crystal
light valve, a dlgltal mrcromirror device may be used.
[0119]
In the foregoing embodiments, although the laser
light sources are used in all of the light source devices
for the respective color light components of R, G, and B,
the laser light sources may be used in the light source
devices of some color light components. For example, the
invention can be applied to a projector including a light
source device which generates other color light components
using a monochrome laser light source and a wavelength
conversion element. In addition, the number, arrangement,
and the like of various constituent elements of the
projector can be approprrately changed.
[Reference Signs List]
[0120]
1, 2 projector,
3R: red liquid crystal light valve (light
modulation element),
3G: green liquid crystal light valve (light
modulation element),
3B : blue liquid crystal light valve (light
modulation element),
7R: red laser light source,
7G: green laser light source,
7B: blue laser light source,
10: light diffusion element, 11: drive device.

We Claim: -
[Claim 1]
A projector comprising:
a laser light source device;
a llght diffusion device;
a light modulation device; and
a projection optical system,
wherein the laser light source device includes a
first laser light source which emits red laser light,
the light diffusion device includes a first light
diffusion element which is provided on the optical path of
the red laser light, and a first drive device which moves
a position where the red laser light is incident on the
first light diffusion element,
the light modulation device includes a first light
modulation element which is provided on the optical path
of light emitted from the first light diffusion element,
light emitted from the first light modulation
element is incident on the projection optical system, and
when the center coordinates of an illumination
distribution of the red laser light in an exit pupil of
the projection optical system are x = 0 and y = 0,
normalized illumination at each coordinate is P (x, y) , and
a calculation range of integration is r (mm), EP
determined from Expression (1) is EP t 35.
[Claim 2]
The projector according to claim 1,
wherein EP determined based on the illumination
distribution of the red laser light is EP 2 51.
[Claim 3]
The projector according to claim 1 or 2,
wherein the laser light source device includes a
second laser light source which emits green laser light,
the light diffusion device includes a second llght
diffusion element which is provided on the optical path of
the green laser light, and a second drlve device which
moves a position where the green laser light is incident
on the second light diffusion element,
the light modulation device includes a second light
modulation element whlch is provided on the optical path
of light emltted from the second light diffusion element,
light emitted from the second light modulation
element is incident on the projection optical system, and
when the center coordinates of an illumination
distribution of the green laser light in the exit pupil of
the projection optical system are x = 0 and y = 0,
normalized illumination at each coordinate is P(x,y), and
a calculation range of integration is r (mm), EP
determined from Expression (1) is EP 2 27.
[Claim 4]
The projector according to claim 3,
wherein EP determined based on the illumination
distribution of the green laser light is EP 2 38.
[Claim 5]
The projector according to any one of claims 1 to 4,
wherein the laser light source device includes a
third laser light source which emits blue laser light,
the light diffusion device includes a third llght
diffusion element which is provided on the optical path of
the blue laser light, and a third drive device which moves
a position where the blue laser llght is incident on the
third light diffusion element,
the llght modulation device includes a third light
modulation element which is provided on the optical path
of light emitted from the third light diffusion element,
light emitted from the third light modulation
element is incident on the projection optical system, and
when the center coordinates of an illumination
distribution of the blue laser light in the exit pupil of
the projection optical system are x = 0 and y = 0,
normalized illumination at each coordinate is P (x, y) , and
a calculation range of integration is r (rnm), EP
determined from Expression (1) is EP 2 16.
[Claim 6]
The projector according to claim 5,
wherein EP determined based on the illumination
distribution of the blue laser light is EP 2 26.
[Claim 7]
A projector comprising:
a laser light source which emits green laser light;
a light diffusion element which is provided on the
optical path of the green laser light;
a drive device which moves a position where the
green laser light is incident on the light diffusion
element;
a light modulation element which is provided on the
optical path of light emitted from the light diffusion
element; and
a projection optical system on which light emitted
from the light modulation element is incident,
wherein, when the center coordinates of an
illumination distribution of the green laser light in an
exit pupil of the projection optical system are x = 0 and
y = 0, normalized illumination at each coordinate is
P (x, y) , and a calculation range of integration is r (mm) ,
EP determined from Expression (1) is EP 2 27.
[Claim 8]
The projector according to claim 7,
wherein EP > 38.
[Claim 9]
A projector comprising:
a laser light source which emits blue laser light;
a light diffusion element which is provided on the
optical path of the blue laser light;
a drive device whlch moves a position where the blue
laser light is incident on the light diffusion element;
a light modulation element which is provided on the
optical path of light emitted from the light diffusion
element; and
a projection optical system on which light emitted
from the light modulation element is incident,
wherein, when the center coordinates of an
illumination distribution of the blue laser light in an
exit pupil of the projection optical system are x = 0 and
y = 0, normalized illumination at each coordinate is
P(x, y), and a calculation range of integration is r (mm),
EP determined from Expression (1) is EP > 16.
[Claim 10]
The projector according to claim 9,
wherein EP 2 26.
[Claim 11]
A projector comprising:
a laser light source device including a first laser
light source which emits red laser light;
a light modulation device including a first light
modulation element which is provided on the optical path
of the red laser light; and
a projection optical system on which light emitted
from the first light modulation element is incident,
wherein, when the center coordinates of an
illumination distribution of the red laser light in an
exit pupil of the projection optical system are x = 0 and
y = 0, normalized illumination at each coordinate is
P ( x , y ) , and a calculation range of integration is r (mm),
EP determined from Expression (1) 1s EP 2 79.
[Claim 12]
The projector according to claim 11,
wherein EP determined based on the illumination
distribution of the red laser light is EP > 119.
[Claim 13]
The projector according to claim 11 or 12,
wherein the laser light source device further
includes a second laser light source which emits green
laser light,
the light modulation device further includes a
second light modulation element which is provided on the
optlcal path of the green laser light,
light emitted from the second light modulation
element is incident on the projection optical system, and
when the center coordinates of an illumination
distribution of the green laser light in the exit pupil of
the projection optical system are x = 0 and y = 0,
normalized illumination at each coordinate is P(x, y) , and
a calculation range of integration is r (mm), EP
determined from Expression (1) is EP > 65.
[Claim 14]
The projector according to claim 13,
wherein EP determined based on the illumination
distribution of the green laser light is EP > 93.
[Claim 15]
The projector according to any one of claims 11 to
14,
wherein the laser light source device further
includes a third laser light source which emits blue laser
light,
the light modulation device further includes a third
light modulation element which is provided on the optical
path of the blue laser light,
light emitted from the third light modulation
element is incident on the projection optical system, and
when the center coordinates of an illumination
distribution of the blue laser light in the exit pupil of
the projection optical system are x = 0 and y = 0,
normallzed illumination at each coordinate is P (x, y) , and
a calculation range of integration is r (rnrn), EP
determined from Expression (1) is EP 2 45.
[Claim 16]
The projector according to claim 15,
whereln EP determined based on the illumination
distribution of the blue laser light is EP > 59.
[Claim 17]
A projector comprising:
a laser light source which emits green laser light;
a llght modulation element which is provided on the
optical path of the green laser light; and
a projection optical system on which light emitted
from the light modulation element is incident,
wherein, when the center coordinates of an
illumination distribution of the green laser light in an
exit pupil of the projection optical system are x = 0 and
y = 0, normalized illumination at each coordinate is
P(x,y), and a calculation range of integration is r (mm),
EP determined from Expression (1) is EP 2 65.
[Claim 18]
The projector according to claim 17,
wherein EP 2 93.
[Clam 19]
A projector comprising:
a laser light source which emits blue laser light;
a light modulation element which is prov~ded on the
optical path of the blue laser light; and
a projection optical system on which light emitted
from the light modulation element is incident,
wherein, when the center coordinates of an
illumination distribution of the blue laser light in an
exit pupil of the projection optical system are x = 0 and
y = 0, normalized illumination at each coordinate is
P (x, y) , and a calculation range of integration is r (rnrn) ,
EP determined from Expression (1) is EP t 45.
[Claim 20]
The projector according to claim 19,
wherein EP t 59.
[Claim 21]
The projector according to any one of claims 1 to 20,
wherein the normalized illumination P(x,y) is
expressed by Expression (2).
P (x, y) = illumination (cd/rn2) / average illumination
(cd/mz) of the top 0.1% in an illumination distribution of
a pupil diameter ... (2)
[Claim 22]
The projector according to any one of claims 1 to 21,
wherein the normalized illumination P(x,y) is
determined as a value integrated over a unit time.
[Claim 23]
The projector accord,ing to any one of claims 1 to 22,
wherein the laser light source device is a multimode
semiconductor laser light source.