TITLE OF THE INVENTION
OCULAR FUNDUS IMAGING SYSTEM
TECHNICAL FIELD
[00011
This invention relates to an ocular fundus imaging system
that is configured to take a fundus of a subject eye with
two or more cameras.
BACKGROUND ART
[00021
Various configurations of ocular fundus imaging systems to
watch eyes of subjects and/or take images thereof have been
proposed, and such systems for carrying out both imaging
modes, color imaging and autofluorescence imaging (FAF
imaging) have been also proposed (see patent related document
1).
[00031
Fig.4 (a) is a block diagram that shows an instance of a
configuration of a conventional ocular fundus imaging system
wherein a reference C 1 denotes a first camera for color
imaging, a reference number C2 denotes a second camera for
carrying out an alignment at the time of the color imaging
and the autofluorescence imaging, and a reference number 30
denotes a dichroic mirror for guiding a light LB from the
fundus of the subject's fundus (not shown) to the first
camera C1 and the second camera C2 so as to be divided. In
the autofluorescence imaging with the second camera C2 in
such a configuration, the dichroic mirror 30 is moved outside
an optical path (see an arrow Q of Fig.4(b)), and the light
LB is received by the second camera C2 without dividing the
light.
PRIOR ART
PATENT-RELATED DOCUMENT
[00041
[Patent-related document 11: Japanese Patent Application
Publication No.2014-226371
DISCLOSURE OF INVENTION
PROBLEMS TO BE SOLVED BY INVENTION
[0005]
If the dichroic mirror 30 is moved outside the optical path,
but, the optical path of the light LB is shifted from an
optical axis R of the second camera C2 (see a reference
number 6 of Fig.4(b), and it is not possible to obtain a
proper image.
[00061
The object of the invention is to provide an ocular fundus
imaging system for solving the above-mentioned problems.
MEANS FOR SOLVING PROBLEMS
[00071
A first aspect of the invention exemplarily shown in Fig.1
is an ocular fundus imaging system (1)' comprising:
an illuminator (2) that irradiates light to a fundus of
a subject eye ( E ) ;
an optical path divider (30) that is configured to be
freely moved, and that divides a reflected light (LB) that
is reflected from the fundus by irradiating the light through
the illuminator (2) into two optical paths (PB1, PB2) ("the
first optical pathN and 'the second optical path"
hereinafter) when being located in an optical path of the
reflected light (LB) (see a reference number PB, "the
reflected optical path" hereinafter);
an optical path corrector (31) that is configured to be
freely moved and that guides the reflected light (LB) to the
second optical path (PB2) when being located in the reflected
optical path ( P B ) ;
a first camera attaching section (4) that attaches a
first camera (Cl) at a position where the reflected light
(LB) that passes through the first optical path (PBl) is
able to be received;
a second camera (C2) that is located at a position where
the reflected light (LB) that passes through the second
optical path (PB2) is able to be received;
a reflected optical path switcher (32) that movably
supports the optical path divider (30) and the optical path
corrector (31) and switches the optical path in such a way
that one of the optical path divider (30) and the optical
path corrector (31) is selectively located in the reflected
optical path (PB) and the other is located outside the
reflected optical path (LB);
a first filter (Fl) that transmits light in a first
wavelength range;
a first filter moving section (GI) that movably supports
the first filter (El) to a position in an optical path
between the illuminator (2) and the fundus (see a reference
number PA, "the illumination path" hereinafter) ("the first
filter insertion position" hereinafter) or a position
outside the illumination path ("the first filter extraction
position" hereinafter);
a second filter (F2) that transmits light in a second
wavelength range;
a second filter moving section (G2) that movably
supports the second filter (E2) to an upstream position
rather than a position in the reflected optical path (PB)
where the optical path corrector (31) is located ("the second
f2lter insertion position" hereinafter) or a position
outside the reflected optical path ("the second filter
extraction position" hereinafter); and
an imaging mode switcher (5) that switches a first
imaging mode wherein the first filter ( F l ) is moved to the
first filter extraction position by driving the first filter
moving section (GI), the second filter (F2) is moved to the
second filter extraction position by driving the second
filter moving section ( G Z ) , and the optical path divider
(30) is located in the reflected optical path (PB) and the
optical path corrector.(31) is located outside the reflected
optical path by driving the reflected optical path switcher
(32) or a second imaging mode wherein the first filter (Fl)
is moved to the first filter insertion position by driving
the first filter moving section (GI), the second filter (F2)
is moved to the second filter insertion position by driving
the second filter moving section (G2), and the optical path
divider (30) is located outside the reflected optical path
and the optical path corrector (31) is located in the
reflected optical path (PB) by driving the reflected optical
path switcher (32).
[0008]
A second aspect of the invention is the ocular fundus
imaging system (I), wherein the second camera (C2) is
configured so as to take still images and moving images, and
it is possible to take moving images when watching the fundus
with the second camera (C2) in the first imaging mode and
the second imaging mode.
[0009]
A third aspect of the invention is the ocular fundus
imaging system ( I ) , further comprising an amplifier (90)
that amplifies image signals outputted from imaging element
(C2a) in the second camera (CZ), and a gain adjuster (91)
that adjusts the gain of the amplifier (90) in. the case of
watching the fundus with the second camera (C2) in the first
imaging mode, the case of watching the fundus with the second
camera (C2) in the second imaging mode, and in the case of
imaging the fundus with the second camera (C2) in the second
imaging mode.
[OOlO]
A fourth aspect of the invention is the ocular fundus
imaging system ( I ) , wherein the first filter (F1) is an
exciter filter which can pass the light in the wavelength
range 500nm to 600nm, and the second filter (F2) is a barrier
filter which can pass the light in the wavelength range 640nm
to 740nm.
[OOll]
A fifth aspect of the invention is the ocular fundus
imaging system (I), wherein the optical path divider (30) is
a dichroic mirror which reflectance of the Light in the
wavelength range 450nm through 650nm is 98% or more and
transmissivity of the light in the wavelength range 800nm
through 950nm is 90%, and
the optical path corrector (31) is a glass which
transmissivity in the wavelength range 630nm through 950nm
is 98 % or so.
[OOlZ]
The number in parentheses shows the corresponding element
in the drawings for the sake of convenience, accordingly,
the descriptions are not restricted and bound by the
descriptions on the drawings.
EFFECTS OF INVENTION
[00131
According to the lSt, Znd, 4th and 5th aspects of the
invention, in the first imaging mode, the reflected light is
divided through the optical path divider so that both the
first and second cameras can receive light. In such a
configuration, it is possible to properly image the fundus
(preferably, the color imaging) with the first camera while
watching the fundus with the second camera. And, in the
second imaging mode, the first camera receives the reflected
light, so that it is possible to carry out the
autofluorescence imaging by using the suitable filters as
the first and second filters. Furthermore, when carrying
out the second imaging mode, the optical path corrector is
located so as to guide the reflected light to the second
camera, so that it is possible to obtain the proper fundus
image without generating a shift between the optical axis of
the second camera and the reflected light.
[00141
According to the 3rd aspect of the invention, it is possible
to obtain uniform images with proper brightness in all
imaging cases.
BRIEF DESCRIPTION OF DRAWINGS
[00151
Fig.1 is a block diagram that shows an example of a
structure of an ocular fundus imaging system according to
the invention.
Fig.2 is a view that shows optical characteristics of an
optical path divider, a first filter and a second filter
wherein Hl shows a reflectance of the optical path divider,
H2 shows a transmissivity of the first filter, and H3 shows
a transmissivity of the second filter.
Fig.3 (a) is a front view that shows an example of a shape
of a holed mirror, Fig.3(b) is a side view of Fig.3(a), and
Fig.3(c) is a front view that shows an example of a shape of
a ring slit.
Fig. 4 (a) , (b) are typical views for explaining conventional
problems, and Fig.4(c) is a typical view for explaining
effects of the invention.
PREFERRED EMBODIMENT
[0016]
Embodiments of the inventj-on are now explained, referring
to appended figures Figs.1 through 4.
[00171
An ocular fundus imaging system according to the invention
is exemplarily shown with a reference number 1 in Fig.1, and
has at least the followings.
-an illuminator 2 that irradiates illumination light LA to
a fundus of a subject eye E
.an optical path divider 30 that is configured to be freely
moved, and that divides a reflected light LB that is
reflected from the fundus by irradiating the illumination
light through the illuminator 2 into two optical paths PBl,
PB2 ("the first optical path" and "the second optical path"
hereinafter) when being located in an optical path PB of the
reflected light LB ("the reflected optical path"
hereinafter)
*an optical path corrector 31 that is configured to be freely
moved and that guides the reflected light LB to the second
optical path PB2 when being located in the reflected optical
path PB
'a first camera attaching section 4 that attaches a first
camera C1 at a position where the reflected light LB that
passes through the first optical path PB1 is able to be
received
.a second camera C2 that is located at a position where the
reflected light LB that passes through the second optical
path PB2 is able to be received
- a reflected optical path switcher 32 that movably supports
the optical path divider 30 and the optical path corrector
31 and switches the optical path in such a way that one of
the optical path divider 30 and the optical path corrector
31 is selectively located in the reflected optical path PB
and the other is located outside the reflected optical path
.a first filter F1 that transmits light in a first wavelength
range
.a first filter moving section GI that movably supports the
first filter F1 to a position in an optical path PA between
the illuminator 2 and the fundus ("the illumination path"
hereinafter) ("the first insertion position" hereinafter) or
a position outside the illumination path ("the first filter
extraction position" hereinafter)
a a second filter F2 that transmits light in a second
wavelength range - a second filter moving section G2 that movably supports
the second filter F2 to an upstream position rather than a
position in the reflected optical path PB where the optical
path corrector 31 is located (that is, the position in the
reflected optical path PB between the fundus and the optical
path corrector 31, "the second filter insertion position"
h e r e i n a f t e r ) or a p o s i t i o n o u t s i d e t h e r e f l e c t e d o p t i c a l
path (the second f i l t e r e x t r a c t i o n position" h e r e i n a f t e r )
- a n imaging mode switcher 5 t h a t switches a f i r s t imaging
mode wherein the f i r s t f i l t e r F1 is movedto the f i r s t f i l t e r
e x t r a c t i o n p o s i t i o n by driving the f i r s t f i l t e r moving
section G1, the second f i l t e r F2 is moved t o the second
f i l t e r e x t r a c t i o n p o s i t i o n by driving the second f i l t e r
moving section G2, and t h e o p t i c a l p a t h d i v i d e r 30 is located
i n the r e f l e c t e d o p t i c a l path PB and t h e o p t i c a l path
c o r r e c t o r 31 is l o c a t e d o u t s i d e the r e f l e c t e d o p t i c a l path
by driving the r e f l e c t e d o p t i c a l path switcher 32 or a second
imaging mode wherein the f i r s t filter F1 is moved t o the
f i r s t f i l t e r i n s e r t i o n p o s i t i o n by driving the first f i l t e r
moving section G I , the second f i l t e r F2 is moved t o the
second f i l t e r i n s e r t i o n position by d r i v i n g t h e second f i l t e r
moving section G2, and the o p t i c a l path divider 30 is l o c a t e d
outside t h e r e f l e c t e d o p t i c a l path and the o p t i c a l path
corrector 31 is located i n the r e f l e c t e d o p t i c a l path PB by
driving t h e r e f l e c t e d o p t i c a l path switcher 32.
[0018]
In the s p e c i f i c a t i o n , a s e c t i o n shown with a reference
number D ( t h a t is, the section including the i l l u m i n a t o r 2,
the f i l t e r s Fl, F2, the f i l t e r moving sections G I , G2, the
o p t i c a l path d i v i d e r 30, the o p t i c a l p a t h c o r r e c t o r 31, and
the r e f l e c t e d o p t i c a l path switcher 32) is properly r e f e r r e d
t o as "an ocular fundus imaging device". And, preferably,
the ocular fundus imaging system 1 is comprised of the
o p t i c a l fundus imaging device D, the f i r s t camera C l attached
t o the f i r s t camera attaching s e c t i o n 4 of the o p t i c a l fundus
imaging device D. In t h i s case, a data storage (not shown)
which is a HDD, a SSD or a storage media, such as a SD card,
a USB memory, and a compact f l a s h ( r e g i s t e r e d trademark) may
be located i n the ocular fundus imaging device D so t h a t
images obtained through the f i r s t camera C l o r t h e second
camera C2 can be s t o r e d t h e r e i n . And, a personal computer
PC (concretely speaking, a desktop personal computer, a note
personal computer, a tablet PC or a smartphone) may be
connected with the ocular fundus imaging device D through an
image transporter 8 by a wireless or wired channel so that
images obtained by the first camera C1 or the second camera
C2 can be captured into the personal computer PC through the
image transporter 8. Furthermore, a monitor M may be
connected with the personal computer PC so that images
obtained the respective cameras C1, C2 can be displayed on
the monitor M.
[0019]
The illuminator 2 is an observation light source 20 that
is a halogen lamp or a LED, or an imaging light source 21
that is a xenon flash lamp or a high brightness LED, for
instance. Preferably, a diffusion board 22, a ring slit 60,
the first filter F1, lighting optical systems 61, 63, a ring
slit 62, and a holed mirror 64 are located, and an objective
lens 65 is located at a position opposed to the subject eye
E on a side where the light is radiated from both light
sources 20, 21 (that is, the .downstream side of the
illumination path PA). Preferably, an imaging diaphragm 66
is located at a hole section of the holed mirror 64, and a
focus lens 70 for focus adjustment through moving the
position on the reflected optical path PB, a half mirror 71
and an inside fixation lamp 72 are located on the downstream
side of the imaging diaphragm 66.
[0020]
On the other hand, the optical path divider 30 is a dichroic
mirror (preferably, which reflectance of the light in the
wavelength range 450nm through 650nm that is used for color
imaging is 98% or more and transmissivity of the light in
the wavelength range 800nm through 950nm that is used at a
time of observation before imaging with infrared light is
90%, as exemplarily shown with a reference number Hl in
Fig.2), for instance. The optical path corrector 31 is one
that can reduce the amount of the reflected light advancing
to the first optical path PB1 in a predetermined wavelength
range and can increase the amount of the reflected light
advancing to the second optical path PB2, such as a
transparent glass which transmissivity is 98 % or so in the
wavelength range 630nm through 950nm that is used for
autofluorescence imaging, for instance. In configuration of
the invention, the optical path of the reflected light LB
that is guided through the optical path corrector 31 almost
corresponds with the optical path PB2 of both optical paths
PB1, PB2 that are divided through the optical path divider
30. For such a configuration is taken by various kinds of
methods, such as a method wherein the shape (the thickness)
or the refractive index is almost equal between both the
optical path divider 30 and the optical path corrector 31,
and the position to be located (the position in the middle
of the reflected optical path) or the angle (the posture) is
almost equal between both 30, 31 so that the optical path
after passing the optical path divider 30 is almost equal to
the optical pass passing the optical path corrector 31, and
a method wherein the shape and/or the refractive index is
not almost equal between both 30 and 31, but the position to
be located (the position in the middle of the reflected
optical path) or the angle (the posture) is made proper
between both so that the optical path after passing the
optical path divider 30 is almost equal to the optical path
passing the optical path corrector 31.
[OOZl]
The reflected optical path switcher 32 are driving motors
or various kinds of actuators, for instance.
[0022]
On the other hand, the first camera C1 is the camera on
the market for color imaging, preferably a digital camera
capable of imaging in color, for instance, and the second
camera C2 is a monochrome camera capable of autofluorescence
imaging and observing and imaging with infrared light, for
instance, and preferably, is capable of obtaining moving
images as well as still images. Besides, the second camera
C2 may be detachably attached to the ocular fundus imaging
device D, similar to the first camera C1.
[00231
Furthermore, the first filter F1 is an exciter filter which
first wavelength range is 500nm to 600nm (that is, the
exciter filter which can pass the light in the wavelength
range 500nm to 600nm) (see H2 of Fig.2), for instance, and
the second filter F2 is a barrier filter which second
wavelength range is 640nm to 740nm (that is, the barrier
filter which can pass the light in the wavelength range of
640nm to 740nm) (see H3 of Fig.2), for instance. Besides,
the first and second filter moving sections G I , G2 are
drivingmotors, and various kinds of actuators, for instance.
[0024]
In the first imaging mode, the first and second filters F1,
F2 are retracted at the positions outside the optical path,
that is, at the first and second extraction positions, and
the reflected light LB is divided into the first optical
path PB1 and the second optical path PB2 through the optical
path divider 30. For this reason, it is possible to image
in color with the first camera C1 after carrying out
alignment with the second camera C2. At this time,
preferably, the light is ejected from the imaging light
source 21 by pushing down a shutter of the first camera C1.
In the second imaging mode, the reflected light LB advances
to the second optical path PB2. Then, the alignment and the
imaging are done through the second camera C2. Preferably,
the first filter F1 and the second filter F2 are inserted
into the optical path at the same time of the imaging, that
is, when a shutter button is pushed down so that the filters
F1, F2 are inserted, and thereafter, a flash lamp (that is,
the imaging light source 21) emits light, and the image is
captured through the second camera C2. In a case where the
barrier filter which second wavelength range is 640nm to
740nm is used as the second filter F2, and the transparent
glass which transmissivity in the wavelength range 630nm to
950nm is 98% or so is used as the optical path corrector 31,
almost all of the reflected light LB is guided to the second
camera C2 and bright images can be taken.
[0025]
Preferably, the imaging mode switcher 5 is comprised of an
operation section 51 to be operated by an operator, and a
driving controller 52 that sends signals from the operation
section 51 to the filter moving sections GI, G2 and the
optical path switcher 32 and controls these driving. In
Fig.1, a switch, a button, a touch panel or the like is
located on a side of the ocular fundus imaging device D as
the operation section 51 of the imaging mode switcher 51,
and a dedicated circuit board is provided on the side of the
ocular fundus imaging device D as the driving controller 52
of the imaging mode switcher 5. But, alternatively, a
dedicated application software is installed into the
personal computer PC so as to function as the driving
controller 52, and a keyboard or a mouse that is connected
with the personal computer PC may function as the operation
section 51. The other operations (that is, various kinds of
operations necessary for taking the fundus images) may be
put in a similar state. The operation section and the
controller that are necessary for the operations may be
provided on the side of the personal computer PC, or on the
side of the ocular fundus imaging device D.
[0026]
According to the invention, in the first imaging mode,
the reflected light LB is divided through the optical path
divider 30 so that both the first and second cameras C1, C2
can receive light (see Fig.4(a)). So, it is possible to
properly image the fundus (preferably, the color imaging)
with the first camera C1 while watching the fundus with the
second camera C2. And, in the second imaging mode, the first
camera C1 receives the reflected light LB, so that it is
possible to carry out the autofluorescence imaging by using
the suitable filters as the first and second filters F1, F2.
[0027]
If the optical path divider 30 is only moved outside the
optical path when changing the first imaging mode (color
imaging mode) into the second imaging mode (autofluorescence
imaging mode), the optical path of the reflected light LB is
shifted from an optical axis R of the second camera C2, as
shown in Fig.4(b). But, according to the invention, the
optical path corrector 31 is located so as to guide the
reflected light LB to the second camera C2, so that it is
possible to take the proper fundus image without generating
such a shift.
[0028]
Preferably, the switching into the optical path divider 30
or the optical path corrector 31 is not done at the same
time of the shutter operation, but at the same time of the
switching of the imaging mode.
[0029]
When the second camera C2 is configured so as to take still
images and moving images, it is possible to take moving
images when watching the fundus with the second camera C2 in
the first and second imaging modes. As the result, it is
possible to take moving images with the second camera C2
when watching in the first imaging mode ... (I), to take moving
images with the second camera C2 when watching in the second
imaging mode ... (2), and to take still images with the second
camera C2 in the second imaging mode ... (3). But, the optical
path divider 30 is used in the first imaging mode although
the optical path corrector 31 is used in the second imaging
mode and the filters F1, F2 are used at the time of taking
images when imaging in the second imaging mode, so that the
amount of light that the second camera C2 receives is
different. Then, preferably, an amplifier 90 that amplifies
image signals outputted fromthe second camera C2 (concretely
speaking, from imaging element thereof C2a), and a gain
adjuster 91 that adjusts the gain of the amplifier 90 so
that the brightness of the fundus image becomes substantially
constant in the case of watching the fundus with the second
camera C2 in the first imaging mode, the case of watching
the fundus with the second camera C2 in the second imaging
mode, and the case of imaging the fundus with the second
camera C2 in the second imaging mode. By doing so, it is
possible to obtain uniform images with proper brightness in
all cases (1) to (3). Preferably, the gain of the first
camera C1 (an imaging element la) in the first imaging mode
is adjusted as well as the gain of the second camera C2.
The gain adjuster 91 may be provided inside a main body (that
is, the inside of the ocular fundus imaging device D) as
exemplarily shown in Fig.1, or may be provided so as to
connect the outside of the main body (that is, the outside
of the ocular fundus imaging device D), or a dedicated
application software may be installed in the personal
computer PC so that the personal computer PC functions as
the amplifier 90 or the gain adjuster 91.
[0030]
An instance for determining size of the gain is now
mentioned. When comparing the case (1) (that is, the case
of taking moving images with the second camera C2 when
watching in the first imaging mode) and the case (2) (that
is, the case of taking moving images with the second camera
C2 when watching in the second imaging mode) with each other,
the amount of light in the case (1) is smaller than one in
the case of (2) under an influence of the dichroic mirror.
Then, the gain in the case (1) is made bigger than one in
the case (2). On the other hand, in the case (3) (that is,
the case of taking the still images with the second camera
C2 in the second imaging mode), preferably, the gain is set
bigger for a purpose of reducing a burden on the subject by
taking the images with the smaller amount of light as much
as possible. On the contrary, the gain may be smaller for
reducing noise of the image and the amount of light for
taking images may be increased for the purpose of obtaining
high quality images. For these reasons, it is convenient if
the examiner is able to optionally set the gain and the
amount of the light for taking images, and is also able to
select one of combinations of the gain and the amount of
such a light that are often used.
[00311
Preferably, the fundus is observed over a relatively wide
range when watching the fundus image. Preferably, on the
other hand, it is desired that an edge of the fundus image
(the peripheral portion) is removed at the time of taking
images so that a flare does not appear in the image since
the flare is easy to appear on the edge of the fundus image.
One method to do so is to locate a visual field mask 73 made
of metal or the like on the downstream side of the optical
path of the half mirror 71 (the lower side of the figure) so
as to remove the flare. But, a considerably low-resolution
camera is often used as the second camera C2 for
autofluorescence imaging since in such a camera, being highly
sensitive has a higher priority, so that the edge portion of
the visual field mask 73 that is cut off in the shape of a
circle is not a perfect circle but a zigzag line, and is not
good looking. Then, preferably, an electronic mask is
automatically used for the still image taken through the
second camera C2 so that the bounds of the image obtained is
made narrower than the observation bounds in order to remove
the flare.
[00321
Preferably, a diaphragm is unified with the second filter
F2. In such a case, it is possible to simultaneously adjust
the amount of light for taking images (the reflected light)
(change the diaphragm diameter) in the second imaging mode
(autofluorescence imaging).
[00331
In a case of the non-mydciasis autofluorescence imaging,
the light may not sufficiently reach the fundus from the
illuminator 2, depending on the miosis state of the subject
and for this reason, the image may be dark. As a
countermeasure, if a diameter of the hole of the holed mirror
64 is b and an inclined angle is 0 as shown in Fig.3(b), an
diameter a (see Fig.3(c)) of the ring slit 62 may be a = b'
cos0. By doing so, it is possible to increase the amount
of the light that reaches the fundus as much as possible so
as to brighten the obtained image. The size of the ring
slit 62 is a proper one with no unnecessary flare, taking
the inclined angle of the holed mirror 64 into consideration.
But, in many cases, the ring slit 62 having rather bigger
size is actually designed in consideration of the problem of
the light circumstance and the balance of various kinds of
elements. When effectively using the amount of the light in
this way, the ocular fundus imaging device can be suppressed
from being increased in size and weight and heating quantity
since it is not necessary to use the big-sized illuminator
with much quantity of ejection light.
EXPLANATION OF REFERENCE NUMBERS
100341
4 ...... first camera attaching section
5 ...... imaging mode switcher
30 ...... optical path divider
31 ...... optical path corrector
32 ...... reflected optical path switcher
90 ...... amplifier
91 ...... gain adjuster
C1 ...... first camera
C2 ...... second camera
F1 ...... first filter
F2 ...... second filter
GI ...... first filter moving section
G2 ...... second filter moving section
LB ...... reflected light
PA ...... optical path
PB ...... reflected optical path
PB1 ...... first optical path
PB2 ... ... second optical path

CLAIMS:
1. An ocular fundus imaging system, comprising:
an illuminator that irradiates light to a fundus of a
subject eye;
an optical path divider that is configured to be freely
moved, and that divides a reflected light that is reflected
from the fundus by irradiating the light through the
illuminator into two optical paths ("the first optical path"
and 'the second optical path" hereinafter) when being located
in an optical path of the reflected light ("the reflected
optical path" hereinafter) ;
an optical path corrector that is configured to be freely
moved and that guides the reflected light to the second
optical path when being located in the reflected optical
path;
a first camera attaching section that attaches a first
camera at a position where the reflected light that passes
through the first optical path is able to be received;
a second camera that is located where the reflected light
that passes through the second optical path is able to be
received;
a reflected optical path switcher that movably supports
the optical path divider and the optical path corrector and
switches the optical path in such a way that one of the
optical path divider and the optical path corrector is
selectively located in the reflected optical path and the
other is located outside the reflected optical path;
a first filter that transmits light in a first wavelength
range;
a first filter moving section that movably supports the
first filter to a position in an optical path between the
illuminator and the fundus ("the illumination path"
hereinafter) or a position outside the illumination path
("the first filter extraction position" hereinafter);
a second filter that transmits light in a second
wavelength range;
a second filter moving section that movably supports the
second filter to an upstream position rather than a position
in the reflected opticdl pdtl~ where the optical path
corrector is located ("the second filter insertion position"
hereinafter) or a position outside the reflected optical
path ("the second filter extraction position" hereinafter);
and
an imaging mode switcher that switches a first imaging
mode wherein the first filter is moved to the first filter
extraction position by driving the first filter moving
section, the second filter is moved to the second filter
extraction position by driving the second filter moving
section, and the optical path divider is located in the
reflected optical path and the optical path corrector is
located outside the reflected optical path by driving the
reflected optical path switcher or a second imaging mode
wherein the first filter is moved to the first filter
insertion position by driving the first filter moving section,
the second filter is moved to the second filter insertion
position by driving the second filter moving section, and
the optical path divider is located outside the reflected
optical path and the optical path corrector is located in
the reflected optical path by driving the reflected optical
path switcher.
2. The ocular fundus imaging system according to claim 1,
wherein the second camera is configured so as to take
still images and moving images, and it is possible to take
moving images when watching the fundus with the second
camera in the first imaging mode and the second imaging
mode.
3. The ocular fundus imaging system according to claim 2,
19
further comprising an amplifier that amplifies image
signals outputted from imaging element in the second
camera, and a gain adjuster that adjusts the gain of the
amplifier in the case of watching the fundus with the
second camera in the first imaging mode, and the case of
watching the fundus with the second camera in the second
imaging mode, and the case of imaging the fundus with the
second camera in the second imaging mode.
4. The ocular fundus imaging system according to claim 1,
wherein the first filter is an exciter filter which can
pass the light in the wavelength range 500nm to 600nm,
and the second filter is a barrier filter which can pass
the light in the wavelength range 640nm to 740nm.
5. The ocular fundus imaging system according to claim 4,
wherein the optical path divider is a dichroic mirror
which reflectance of the light in the wavelength range
450nm through 650nm is 98% or more and transmissivity of
the light in the wavelength range 800nm through 950nm is
90%, and
the optical path corrector is a glass which
transmissivity in the wavelength range 630nm through 950nm
is 98 % or so.