JP3827126B2 - Fundus photographing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fundus imaging apparatus, and more particularly to a fundus imaging apparatus that can automatically adjust the working distance of a fundus imaging optical system.
[0002]
[Prior art]
One of the ophthalmologic apparatuses is a fundus photographing apparatus (fundus camera). This is an apparatus for photographing the fundus of the eye to be examined.
[0003]
Since the fundus photographing apparatus performs illumination and photographing through the pupil, it is important to align the fundus photographing optical system with the pupil of the eye to be examined. In the conventional fundus imaging apparatus, imaging is performed according to the following procedure. First, the front limit part of the eye to be examined facing the front is observed with the anterior eye observation optical system, and the optical axis is aligned so that the pupil appears in the center of the observation screen. Thereby, rough alignment is performed.
[0004]
Then, the optical system is switched from the anterior ocular photographing optical system to the fundus photographing optical system. Then, the bright spot image received by the television camera is displayed on the monitor screen.
[0005]
FIG. 10 shows a monitor screen at this time. On the monitor screen 160, two bright spot images 162 appear in a field frame 161. The bright spot image 162 is obtained by reflecting the index light projected onto the eye to be examined from the photographing optical axis direction of the fundus photographing optical system by the eyeball and capturing the reflected image by the television camera. The optical system and the television camera that project the index light are fixed to a mirror body on which the fundus photographing optical system is arranged.
[0006]
This mirror can be moved in the direction of the photographing optical axis of the fundus photographing optical system by manually moving the joystick back and forth. When the fundus photographing optical system is at a working distance with respect to the eye to be examined, the index projection optical system or the television camera is formed so that an eyeball reflection image of the index light is formed on the image receiving element (CCD) of the television camera. Is arranged. Therefore, the operator of the fundus imaging apparatus operates the joystick while looking at the monitor screen 160 to adjust the movement of the mirror so that the bright spot image 162 looks sharpest on the monitor screen 160. In this way, the working distance is adjusted.
[0007]
On the other hand, this mirror can be moved in a plane perpendicular to the photographing optical axis of the fundus photographing optical system by manually moving the joystick left and right and manually rotating the upper and lower handles. When the mirror is moved in a plane orthogonal to the photographing optical axis of the fundus photographing optical system, the position of the bright spot image 162 moves on the monitor screen 160. When the fundus photographing optical system is aligned with the eye to be examined, the index projection optical system and the television camera are arranged so that the bright spot image 162 is positioned at a predetermined point on the monitor screen 160. In the monitor screen of FIG. 8, a position slightly inside the rectangular protrusion formed at the left and right ends of the field frame 161 is a position where the bright spot image 162 should be guided. Therefore, the operator of the fundus imaging apparatus operates the joystick and the upper and lower handles while looking at the monitor screen 160 so that the two bright spot images 162 are positioned inside the protruding portion of the field frame 161 on the monitor screen 160. To. In this way, alignment is performed by guiding the position of the bright spot image 162 with reference to the field frame 161.
[0008]
When the working distance alignment and alignment are completed, the index light is turned off, the fundus photographing optical system is focused, and the fundus photographing is performed after the focusing is completed.
[0009]
[Problems to be solved by the invention]
As described above, the fundus imaging apparatus that manually adjusts the working distance requires a complicated operation. In addition, since it takes time until imaging, the subject is forced to be nervous for a long time.
[0010]
On the other hand, various automatic alignment type ophthalmologic apparatuses that automatically align the main optical system with respect to the eye to be examined have been developed. This automatic alignment uses an eyeball reflection image of light irradiated on the eyeball as an alignment index. Therefore, it is conceivable to apply this technique to a fundus photographing apparatus to perform automatic alignment of the fundus photographing optical system. However, even if only alignment is automated, if the working distance alignment is not automated, the series of operations of the fundus imaging apparatus cannot be automated, so there is little value for practical use. However, as described above, the working distance adjustment is performed by the operator searching for a position where the bright spot image can be seen sharply by operating the joystick, and a large part depends on the experience and intuition of the operator. Such work is difficult to automate, and is a factor that hinders automation of a series of operations of the fundus imaging apparatus.
[0011]
In view of the above problems, an object of the present invention is to provide a fundus photographing apparatus suitable for automation of working distance alignment.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, a fundus imaging apparatus according to the invention of this application includes a fundus imaging optical system for imaging the fundus of the eye to be examined, and a first moving the fundus imaging optical system in the imaging optical axis direction of the fundus imaging optical system. Driving means; Second driving means for moving the fundus photographing optical system in a plane orthogonal to the photographing optical axis of the fundus photographing optical system; An index projection optical system for projecting an index having a lattice pattern from the imaging optical axis of the fundus imaging optical system onto the eye to be examined, the index projection optical system being provided so as to be movable integrally with the fundus imaging optical system; An image receiving means for receiving a reflected image from the eye spherical surface of the index, which is provided so as to be movable integrally with the fundus photographing optical system, and a control means, and the fundus photographing optical system and the index projection The optical system and the image receiving means are arranged in a positional relationship such that the reflected image is formed by the image receiving means when the fundus photographing optical system is located at a working distance with respect to the eye to be examined. , Based on the imaging state of the reflected image received by the image receiving means, driving and controlling the first driving means so that the reflected image is formed by the image receiving means, The second drive unit is driven and controlled so that the reflected image is positioned at a predetermined position on the image receiving screen of the image receiving unit. (Claim 1). Thus, the index has a configuration suitable for contrast detection. And since the image formation state of the index reflection image on the image receiving means can be determined by contrast detection, the working distance adjustment can be automated. With this configuration, the index functions as an index for alignment, and automatic alignment can be performed even after the optical system is switched to the fundus imaging optical system.
[0013]
In the fundus imaging apparatus, the index projection optical system uses the index as convergent light so that the index is reflected as parallel light from the eye spherical surface when the fundus imaging optical system is located at a working distance with respect to the eye to be examined. You may comprise so that it may project on a to-be-examined eye (Claim 2).
[0015]
Further, in the fundus photographing apparatus, the center of the right eye pupil in which the photographing optical axis of the fundus photographing optical system is fixed by the right eye fixation lamp when the reflected image is guided at the predetermined position. The first set position that substantially coincides with the center of the pupil of the left eye whose optical axis is fixed by a fixation lamp for the left eye when the reflected image is guided. The second setting position to be switched may be configured to be switchable ( Claim 3 ). If comprised in this way, according to each of the right eye and the left eye, it will become possible to align so that an imaging optical axis may not be obstruct | occluded by an iris, and a clear fundus image can be image | photographed now.
[0016]
In the fundus imaging apparatus, the lattice pattern of the index is a vertically symmetric and left-right symmetric pattern ( Claim 4 Is preferred.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
First, based on FIG. 1, the apparatus structure of the fundus imaging apparatus 1 which is an embodiment of the present invention will be described. FIG. 1 is a block diagram illustrating a schematic configuration of the fundus imaging apparatus 1. The fundus photographing apparatus 1 includes a mirror body 3 on which various optical systems are arranged, a drive mechanism (Z-axis drive mechanism 51, XY-axis drive mechanism 52) for driving the mirror body 3, and a TV camera 10. And a control circuit 53 serving as a control means for processing the image signal and controlling driving of the drive mechanisms 51 and 52. On the lens body 3, optical systems such as a fundus photographing optical system Sa and an index projection optical system Sb are arranged.
[0019]
The fundus photographing optical system Sa is an optical system Sa1 for illuminating the fundus of the eye E, an optical system Sa2 for photographing the fundus based on the illumination light of the optical system Sa1, and a focus of the optical system Sa2 on the eye E. The optical system Sa3 for adjusting to the fundus of the eye.
[0020]
The optical system Sa1 includes a strobe discharge tube 11, condensing lenses 12, 13, a circular slit 14, a mirror 15, condensing lenses 18, 19, and a perforated mirror 6. This optical system is for irradiating the eye E with the visible light emitted from the strobe discharge tube 11 along the imaging optical axis A of the fundus imaging optical system Sa and irradiating the fundus retinal surface.
[0021]
The optical system Sa2 includes an objective lens 5, a focus lens 7, a relay lens 8, and a television camera 10. Reference numeral 9 denotes a CCD of the TV camera 10. These members are disposed on the photographing optical axis A of the fundus photographing optical system Sa. The fundus image passes through the objective lens 5 and the like, and is imaged and photographed on the CCD 9 as image receiving means. The focus lens 7 functions as a focus adjustment unit that adjusts the focus of the fundus photographing optical system Sa.
[0022]
The optical system Sa3 includes a halogen lamp 21, a condenser lens 22, an automatic focus index slit 23, a projection lens 24, a split prism 25, a condenser lens 26, and a half mirror 20. Among these, the halogen lamp 21, the condenser lens 22, the automatic focus index slit 23, the projection lens 24, and the split prism 25 integrally form a movable portion 27. The movable portion 27 is interlocked with the focus lens 7. This optical system Sa3 is for focusing the fundus photographing optical system Sa.
[0023]
The index projection optical system Sb includes an infrared light emitting diode 30, a chart 31, a condenser lens 32, and an infrared half mirror 33 arranged on the optical axis B. As will be described later, the index projection optical system Sb generates an index to be projected onto the eye E. In this embodiment, the CCD 9, which is one component of the fundus photographing optical system Sa, is used as the eye spherical surface of the index. It is used as an image receiving means for receiving reflected light. However, the image receiving means may be provided completely separate from the fundus photographing optical system Sa. In that case, it is preferable to provide an image receiving means for receiving the eyeball reflected light of the index at a position equivalent to the image receiving element of the fundus photographing television camera of the fundus photographing optical system.
[0024]
Between the gantry of the fundus imaging apparatus 1 and the mirror body 3, a Z-axis drive mechanism 51 as a first drive means and an XY-axis drive mechanism 52 as a second drive means are interposed. The position of the mirror body 3 with respect to the gantry is changed by these drive mechanisms 51 and 52. The Z-axis drive mechanism 51 is a drive mechanism for moving the mirror body 3 in the Z direction. Here, the Z direction is a direction (left-right direction in FIG. 1) in which the eye E is approached / separated. Note that the direction of the photographic optical axis A coincides with the Z direction. The XY axis drive mechanism 52 is a drive mechanism for moving the mirror body 3 in the XY direction. Here, the X direction refers to a direction orthogonal to the Z axis in a horizontal plane (a direction perpendicular to the paper surface in FIG. 1). The Y direction refers to the vertical direction (the vertical direction in FIG. 1).
[0025]
The control circuit 53 receives an image signal from the television camera 10 and sends a drive control signal to the Z-axis drive mechanism 51 and the XY-axis drive mechanism 52 based on the image signal. The mirror body 3 is moved by the control of the control circuit 53 in this way. As described above, the fundus photographing optical system Sa and the index projection optical system Sb are disposed on the mirror body 3. Due to the movement, the index projection optical system Sb and the CCD 9 move integrally with the fundus photographing optical system Sa.
[0026]
The fundus imaging apparatus 1 is generally configured as described above, and the working distance is aligned and aligned using the index light generated by the index light projection optical system Sb. However, the working distance alignment by the index light projection optical system Sb, the alignment while observing the anterior eye part of the eye E before the alignment is performed, and the operation by the working distance index projected from the oblique direction to the eye E The distance is adjusted by an optical system disposed on the mirror body 3. Although these optical systems are not shown, the operation of these optical systems is outlined as follows.
[0027]
That is, the alignment while observing the anterior eye part was projected from the front onto the eye spherical surface F of the eye E while receiving the anterior eye part of the eye E by a television camera of an anterior eye observation optical system (not shown). This is performed by moving the mirror body 3 in the XY directions so that the reflected light of the alignment index light from the eye spherical surface F falls within a predetermined range on the image receiving screen of the television camera. This control is performed when the control circuit 53 receives an image signal from the television camera and sends a drive control signal to the XY axis drive mechanism 52.
[0028]
In addition, the working distance alignment by the working distance index projected on the eye E from an oblique direction is performed as follows. That is, while the working distance index projection optical system (not shown) irradiates the eye spherical surface F of the eye E with the working distance index obliquely from the front, the eyeball reflected light of this working distance index is received by the working distance detection optical system (not shown). Until the mirror 3 is moved in the Z direction. This control is performed by sending a drive control signal to the Z-axis drive mechanism 51 while the control circuit 53 receives a signal from the working distance detection optical system. This working distance is adjusted while maintaining the alignment state by the anterior ocular segment observation optical system.
[0029]
Thus, when the alignment by the anterior ocular segment observation optical system and the working distance alignment by the working distance index projected from the oblique direction to the eye E are completed, the optical system is switched to the fundus photographing optical system Sa. Then, the infrared light emitting diode 30 is caused to emit light, and the eyeball reflected light of the index light generated by the infrared light emitting diode 30 and the chart 31 is received by the television camera 10, and more accurate working distance alignment and alignment are performed. Made.
[0030]
FIG. 2 shows the direction of travel until the index light of the index projection optical system Sb reaches the eye spherical surface F of the eye E to be examined. FIG. 3 shows this index light pattern. The infrared light emitted from the infrared light emitting diode 30 passes through the chart 31 and becomes index light having a specific pattern as shown in FIG. The index light pattern is a lattice pattern. Here, the lattice pattern means a pattern in which bright portions and dark portions appear repeatedly. In measuring the resolution of the lens, for example, a grid pattern such as a resolution chart is used, and this is also used in the fundus imaging apparatus 1 of the present embodiment. As can be seen from FIG. 3, this index light pattern has a bright part c and a dark part d, and the brightness changes abruptly at the boundary between the bright part c and the dark part d. The contrast ratio between the bright part c and the dark part d is preferably higher. Further, the pattern of the index light is vertically symmetrical and laterally symmetric. Moreover, the dark part d comprises four vertical stripes, and thus the pattern of the indicator light has a stripe pattern. This vertical stripe is orthogonal to a scanning line for contrast detection described later. The index light having such a pattern passes through the condenser lens 32 and reaches the infrared half mirror 33. The infrared half mirror 33 is a mirror that transmits visible light without reflecting it, but reflects part of infrared light and transmits part of it. Since the index light of the index projection optical system Sb is composed of infrared light, the infrared half mirror 33 transmits a part of the index light as it is and the rest to the eye E along the photographing optical axis A. Reflect in the direction you head. The index light reflected by the infrared half mirror 33 passes through the perforated mirror 6 and the objective lens 5 and reaches the eye E as convergent light. Since the index light is composed of infrared rays, the subject does not feel dazzling even when irradiated to the eye E, and does not blink due to dazzling. A part of the convergent light is reflected by the eye spherical surface F.
[0031]
FIG. 4 shows the direction of travel of the reflected light of the eyeball by the index light with arrows. The reflected spherical light of the index light travels in the direction away from the eye E along the imaging optical axis A. The reflected eyeball light passes through the objective lens 5 and the perforated mirror 6 and reaches the infrared half mirror 33. The infrared half mirror 33 reflects a part of the reflected spherical light in the direction of the optical axis B and passes the rest. The ocular spherical reflected light that has passed through the infrared half mirror 33 passes through the focus lens 7 and the relay lens 8 along the photographing optical axis A, and is received as an index reflected image by the CCD 9 of the television camera 10.
[0032]
FIG. 5 shows an image receiving screen 60 of the television camera 10 at this time. On the inner side of the field frame 61 of this screen, a pattern having a circular outline and four vertical stripes appears. This pattern is a pattern of the index reflection image. The sharpness of the index reflected image on the image receiving screen 60 changes when the mirror 3 moves in the Z direction. The arrangement relationship of the fundus photographing optical system Sa, the index projection optical system Sb, and the CCD 9 as the image receiving means on the mirror body 3 is such that when the fundus photographing optical system Sa is located at the working distance with respect to the eye E, the index reflection image is the CCD 9. The arrangement is such that an image is formed. If the fundus photographing optical system Sa is at a working distance with respect to the eye E, the index light is reflected as parallel light by the eye spherical surface F as shown in FIG. In such a state, the index reflected image appears most clearly on the image receiving screen 60. However, if the fundus photographing optical system Sa is at a position deviated from the working distance with respect to the eye E, the index light is reflected as divergent light or convergent light at the eye spherical surface F, and is not imaged by the CCD 9. The index reflection image is blurred on the image receiving screen 60. The control circuit 53 detects the image formation state of the index reflection image on the CCD 9, and in this embodiment, contrast detection is used for this image formation state detection. That is, since the scanning line S is set in the horizontal direction at a substantially central portion of the image receiving screen 60, it is determined from the frequency component of the signal obtained by the scanning line S whether or not the pattern of the index reflected image is clear. is there. Since the index pattern projected onto the eye E is a lattice pattern, the index reflection image is suitable for detecting the imaging state. This makes it possible to automate the working distance adjustment of the fundus imaging apparatus 1. That is, the control circuit 53 searches the position where the index reflected image appears most clearly on the image receiving screen 60 while moving the mirror 3 in the Z direction based on the imaging state detected by contrast detection. In this way, the working distance adjustment is automated.
[0033]
On the other hand, since the pattern of the index reflection image has a bright part c, the entire pattern can be regarded as a bright spot on the image receiving screen 60. Then, for example, the position of the center point of the pattern captured on the image receiving screen 60 can be detected as the bright spot position. The fundus photographing optical system Sa is automatically aligned by moving the mirror body 3 in the XY directions by the XY axis driving mechanism 52 and guiding the luminescent spot position to a predetermined position on the image receiving screen 60. be able to. If the photographing optical axis A of the fundus photographing optical system Sa is accurately aligned with the eye E, the index light is reflected from the eye spherical surface F along the photographing optical axis A. However, when the photographing optical axis A of the fundus photographing optical system Sa deviates in the XY direction, the index light is reflected at an angle with respect to the photographing optical axis A, so that the bright spot position varies sensitively on the image receiving screen 60. . Thus, the alignment is very accurate.
[0034]
In FIG. 6, the set position set on the image receiving screen 60 to guide the bright spot position is indicated by a rectangle R. That is, the pattern of the index reflection image is guided to a position where the pattern of the index R protrudes equally in all directions (up, down, left and right). In the figure, a broken-line circle Q indicates the contour of the pattern of the index reflection image when guided to such a position. As described above, in the present embodiment, the setting position is provided at a substantially central portion in the image receiving screen 60.
[0035]
The index light pattern by the index projection optical system Sb may be any pattern suitable for detection of the imaging state, that is, any lattice pattern. However, in particular, a vertically symmetric and left-right symmetric pattern as in this embodiment is preferable. Assuming vertical symmetry and left-right symmetry, when the index reflection image is regarded as a bright spot, the bright spot center point coincides with the pattern center point of the index reflection image. Therefore, it becomes easy to use as an alignment index.
[0036]
The index light pattern by the index projection optical system Sb is preferably a pattern having a striped pattern as in the present embodiment. This is because the imaging state can be reliably detected on the scanning line S even if the position of the index reflection image is slightly shifted on the image receiving screen 60.
[0037]
FIG. 7 shows the image receiving screen 60 when the index reflected image is at a position shifted in the scanning line S direction and the direction orthogonal to the scanning line S on the image receiving screen 60. Even in such a case, it can be understood that bright and dark are repeated on the scanning line S, and the imaging state can be detected.
[0038]
When the working distances are aligned and aligned as described above, the fundus photographing optical system Sa is then focused. In focusing, the halogen lamp 21 is turned on, and the movable portion 27 of the optical system Sa3 and the focus lens 7 of the optical system Sa2 are moved in the Z direction by a drive mechanism (not shown) until the focus is detected by a detection optical path (not shown). This is done by interlocking movement.
[0039]
When the focusing of the fundus photographing optical system Sa is completed, the strobe discharge tube 11 is caused to emit light, and a fundus image is photographed by the television camera 10 in synchronization with this.
[0040]
The operation of the fundus imaging apparatus 1 has been described above. As can be understood from the above description, the fundus imaging apparatus 1 can perform automatic alignment not only during observation of the anterior segment but also after the optical system is switched to the fundus imaging optical system Sa. That is, alignment can be performed automatically and extremely accurately until immediately before fundus photography. In addition, after switching to the fundus photographing optical system Sa, the working distance can be automatically adjusted. As described above, the position of the fundus photographing optical system Sa can be aligned in the XY direction and the Z direction until just before fundus photographing while observing the fundus, and the positional accuracy is improved.
[0041]
In the fundus imaging apparatus 1, a predetermined position (set position) on the image receiving screen 60 where the index reflection image should be guided for alignment is provided at a substantially central portion in the image receiving screen 60. However, two predetermined positions for the right eye and the left eye are provided as the predetermined positions for guiding the index reflection image, and the position to be guided can be switched depending on whether the eye to be examined is the right eye or the left eye. It is preferable to be able to configure. As described above, the position for guiding the index reflection image is set separately for each of the right eye and the left eye for the following reason. That is, the fundus imaging apparatus generally includes a fixation lamp for fixing the visual axis of the eye to be examined. The fixation lamp for the right eye and the fixation lamp for the left eye are separate. In a standard imaging method using a fundus imaging apparatus, these fixation lights cause the visual axis of the subject's eye to form an angle of about 6 to 8 degrees from the front to the nose. When the eye to be inspected is viewed from the direction of the photographing optical axis due to the movement of the visual axis by such a fixation lamp, the position of the top of the eye spherical surface and the position of the pupil center are shifted. The shift is symmetric between the right eye and the left eye, but the positional relationship of the pupil center with respect to the top of the spherical surface of the right eye and the left eye is different. For fundus photography, it is suitable to make the photographing optical axis A of the fundus observation optical system Sa coincide with the center of the pupil and make the photographing optical axis A coincide with the center of the image receiving screen 60. On the other hand, a bright spot (index reflected image) for alignment appears on the top of the spherical surface of the eye. Therefore, the position where the bright spot position should be guided should be set to a position shifted from the center of the image receiving screen 60 so that the photographing optical axis A is not obstructed by the iris.
[0042]
FIG. 8 shows on the image receiving screen 60 the first setting position for the right eye set in consideration of such points as a rectangle R1, and the second setting position for the left eye as a rectangle R2. is there. In other words, if the eye to be examined is the right eye, its visual axis is fixed by a fixation lamp for the right eye, and at this time, the pattern of the index reflected image protrudes equally from the rectangle R1 in all directions (up, down, left and right). Induce. If the eye to be inspected is the left eye, the visual axis is fixed by a fixation lamp for the left eye, and at this time, the index reflected image pattern is guided so as to equally protrude from the rectangle R2 in all directions (up, down, left and right). To do. If the eye to be examined is the right eye, the photographing optical axis A of the fundus photographing optical system Sa substantially coincides with the center of the pupil when the bright spot position is guided to the first setting position. If the eye to be examined is the left eye, the photographing optical axis A of the fundus photographing optical system Sa substantially coincides with the center of the pupil when the bright spot position is guided to the second setting position. Thereby, clear fundus photographing can be performed without the photographing optical axis A being blocked by the iris. Circles Q1 and Q2 indicated by broken lines on the image receiving screen 60 indicate the contours of the pattern of the index reflection image when guided to the first setting position and the second setting position, respectively. Also, alternate long and short dash lines S1 and S2 shown on the image receiving screen 60 are scanning lines for contrast detection provided corresponding to the first and second setting positions, respectively.
[0043]
Note that the fixation lamp can move freely so that the visual axis of the eye to be examined can be guided according to the region of the fundus to be photographed. Depending on the direction of the visual axis, the positional relationship between the apex of the eye spherical surface and the pupil center is determined geometrically. In other words, the position of the fixation lamp and the position of the pupil center with respect to the apex of the eyeball surface correspond in a one-to-one relationship. Therefore, the predetermined position where the bright spot position should be guided on the image receiving screen 60 is set according to the position of the fixation lamp so that clear imaging can be performed regardless of the imaging region.
[0044]
FIG. 9 is a diagram showing various index patterns. The fundus imaging apparatus 1 in FIG. 1 generates index light having a pattern as shown in FIG. 3 by the index projection optical system Sb. The fundus imaging apparatus according to the present application is not limited to the one shown in FIG. 9A to 9D may be used.
[0045]
The pattern shown in FIG. 9A is a lattice pattern, the pattern shown in FIG. 9B is a polka dot pattern, and the pattern shown in FIG. 9C is a multi-circle pattern. These are patterns, both of which are a kind of lattice pattern. In addition, both are vertically symmetric and symmetric patterns.
[0046]
The pattern of FIG. 9D is also a pattern in which the bright part and the dark part are repeated, and is a kind of lattice pattern. Moreover, it has the striped pattern which consists of several diagonal stripes.
[0047]
In FIGS. 9A to 9D, a one-dot chain line indicated by S is a scanning line for contrast detection.
[0048]
【The invention's effect】
As described above, according to the fundus imaging apparatus of the present invention, the following effects can be obtained.
[0049]
(1) After the optical system is switched to the fundus photographing optical system, accurate working distance adjustment can be automatically performed.
[0050]
(2) If the second drive unit is driven and controlled so that the index reflected image is positioned at a predetermined position on the image receiving screen of the image receiving unit, automatic alignment can be performed after the optical system is switched to the fundus photographing optical system. It becomes like this.
[0051]
(3) A predetermined position on the image receiving screen on which the reflected image of the index is to be guided, a setting position where the imaging optical axis passes through the center of the right eye pupil, and a setting position where the imaging optical axis passes through the center of the pupil of the left eye If it is configured to be able to be switched, the alignment can be performed so that the imaging optical axis is not obstructed by the iris according to each of the right eye and the left eye, and a clear fundus image can be captured.
[0052]
(4) If the index pattern is vertically and horizontally symmetrical, it is particularly easy to use as index light for alignment.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating a device configuration of a fundus imaging apparatus.
FIG. 2 is an optical path diagram with arrows indicating the traveling direction until the index light of the index projection optical system reaches the eye spherical surface of the eye to be examined.
FIG. 3 is a diagram showing a pattern of index light.
FIG. 4 is an optical path diagram in which an advancing direction of the reflected eyeball light of the index light is indicated by an arrow.
FIG. 5 is a diagram showing an image receiving screen of a television camera.
FIG. 6 is a diagram showing a setting position on which a bright spot should be guided on an image receiving screen.
FIG. 7 is a diagram showing an image receiving screen when an index reflection image is at a position shifted in a scanning line direction and a direction orthogonal to the scanning line on the image receiving screen.
FIG. 8 is a diagram showing a setting position for a right eye and a setting position for a left eye on which an luminescent spot should be guided on an image receiving screen.
FIG. 9 is a diagram showing various index patterns. 9A shows a lattice-shaped index pattern, FIG. 9B shows a polka-dot-shaped index pattern, FIG. 9C shows a multi-circular index pattern, and FIG. 9D shows a striped index pattern. It is a figure which shows a pattern, respectively.
FIG. 10 is a diagram showing a monitor screen.
[Explanation of symbols]
1 Fundus photography device
3 body
6 Mirror
5 Objective lens
7 Focus lens
8 Relay lens
9 CCD
10 TV camera
11 Strobe discharge tube
12,13 condenser lens
14 Circular slit
15 Mirror
18,19 condenser lens
20 half mirror
21 Halogen lamp
22 Condensing lens
23 Automatic focus index slit
24 Projection lens
25 Split prism
26 Condensing lens
27 Moving parts
30 Infrared light emitting diode
31 chart
32 condenser lens
33 Infrared half mirror
51 Z-axis drive mechanism
52 XY axis drive mechanism
53 Control circuit
60 Receiving screen
61 Field frame
A Shooting optical axis
B Optical axis
E Eye to be examined
F Eye sphere
S, S1, S2 scan lines
Sa fundus photographing optical system
Sa1, Sa2, Sa3 optical system
Sb index projection optical system
c Myebu
d Dark part

Claims (4)

A fundus photographing optical system for photographing the fundus of the eye to be examined;
First driving means for moving the fundus photographing optical system in the direction of the photographing optical axis of the fundus photographing optical system;
Second driving means for moving the fundus photographing optical system in a plane orthogonal to the photographing optical axis of the fundus photographing optical system;
An index projection optical system for projecting an index having a lattice pattern from the imaging optical axis of the fundus imaging optical system to the eye to be examined, provided so as to be movable integrally with the fundus imaging optical system;
An image receiving means for receiving a reflected image from the eye spherical surface of the indicator, provided so as to be movable integrally with the fundus photographing optical system;
Control means,
The fundus photographing optical system, the index projection optical system, and the image receiving means are positions at which the reflected image is formed by the image receiving means when the fundus photographing optical system is located at a working distance with respect to the eye to be examined. Placed in a relationship
The control means drives and controls the first driving means so that the reflected image is formed by the image receiving means based on the imaging state of the reflected image received by the image receiving means, and the reflected image is the received image. An ophthalmologic photographing apparatus that drives and controls the second driving means so as to be positioned at a predetermined position on the image receiving screen of the means.   The index projection optical system projects the index as convergent light onto the subject's eye so that the index reflects as parallel light from the eye spherical surface when the fundus photographing optical system is located at a working distance with respect to the subject's eye. The fundus imaging apparatus according to claim 1.   The predetermined position is a first set position where the photographing optical axis of the fundus photographing optical system substantially coincides with the center of the right eye pupil whose visual axis is fixed by a fixation lamp for the right eye when the reflected image is guided. And a second set position where the imaging optical axis of the fundus imaging optical system substantially matches the pupil center of the left eye whose visual axis is fixed by a left eye fixation lamp when the reflected image is guided, The fundus imaging apparatus according to claim 1, wherein the fundus imaging apparatus is configured to be switchable.   The fundus photographing apparatus according to any one of claims 1 to 3, wherein the lattice pattern of the index is a vertically symmetrical and laterally symmetrical pattern.

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