JP4138101B2 - Fundus camera - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a fundus camera in which a focusing lens is provided in a photographing optical system for photographing the fundus of a subject's eye.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a fundus camera including an illumination optical system that illuminates the fundus of a subject's eye and a photographing optical system that captures the fundus is known.
[0003]
In such a fundus camera, in order to photograph a fundus image that favors an alignment optical system for the observation and photographing optical system, the anterior eye portion and the fundus of the eye to be examined are respectively connected via the photographing optical system and the anterior eye observation optical system. It is provided so that it can be photographed with an image sensor of a TV camera, and the anterior eye portion of the eye to be examined is photographed with an image sensor via the anterior eye portion observation optical system, and the photographed anterior eye portion is photographed while being observed on the monitor TV. After aligning the optical system with the anterior ocular segment to be examined, switching from this anterior ocular segment observation to the fundus oculi observation allows the fundus of the subject eye to be imaged with the imaging device via the imaging optical system, and this captured ocular fundus is monitored Some of them are designed for observation and shooting on TV.
[0004]
[Problems to be solved by the invention]
However, in such a fundus camera, it is impossible to know the sharpness of the imaged fundus until switching from anterior ocular segment observation to fundus observation.
[0005]
In order to solve this problem, a fundus camera in which the focus lens is moved and controlled in the optical axis direction after the alignment with respect to the subject's eye is performed on the fundus is considered. ing.
[0006]
However, since the movement control amount of the focusing lens differs depending on the eye refractive power of the eye to be examined, there is a problem that it takes time to focus on a person with high eye refractive power.
[0007]
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a fundus camera that can always focus an image sensor on the fundus in a short time regardless of the eye refractive power of the eye to be examined.
[0008]
[Means for solving problems]
In order to achieve the above object, the invention of claim 1 is directed to an imaging optical system provided with a focusing lens for focusing the imaging means on the fundus of the eye to be examined, and driving control of the focusing lens in the optical axis direction. Lens driving means , Data input means for inputting eye refractive power data of the eye to be examined, and focus start position correcting means for correcting the focus start position by controlling the lens driving means based on the eye refractive power data; , Alignment detection means for detecting alignment of the photographing optical system with respect to the fundus; An optical system driving unit that drives the imaging optical system in a three-dimensional direction; and when the alignment detection unit detects a rough alignment of the imaging optical system with respect to the fundus, the optical system driving unit is driven and controlled, Auto alignment control means for automatically controlling the alignment of the photographing optical system to the fundus A fundus camera comprising:
The focus start position correcting means is set to correct the focus start position by operating the lens driving means based on the eye refractive power data during the alignment control operation by the auto alignment control means. ing It is a fundus camera.
[0009]
The invention of claim 2 2. The fundus camera according to claim 1, further comprising a control device that performs focusing by operating the lens driving unit when the alignment by the auto alignment control unit is completed. Features.
[0010]
The invention of claim 3 2. The fundus camera according to claim 1, wherein a slit transmitted light beam, which is light from a light source and transmitted through a slit-shaped index of a slit index plate, is incident on the eye to be examined, and a slit-shaped index image is projected on the fundus. Equipped with an in-focus detection optical system, The focus start position correcting means controls the lens driving means based on the eye refractive power data during the alignment control operation by the auto alignment control means. The focusing lens and the slit index plate are integrally driven and controlled in the optical axis direction, It is set to correct the focus start position At the same time, when the alignment by the auto-alignment control means is completed, the control device turns on the light source to project the plurality of slit transmitted light beams onto the fundus, and forms a slit image by the plurality of slit transmitted light beams. The imaging unit forms an image on the imaging unit, and the driving unit drives the focusing lens and the slit index plate in a direction in which the imaging unit is focused on the fundus based on an image signal of the imaging unit. Drive control in the optical axis direction It is characterized by that.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a fundus camera according to the present invention will be described below with reference to the drawings.
[0012]
In FIG. 10, 1 is a fixed base of the fundus camera, 2 is a movable base (mounting base) placed on the fixed base 1 so as to be movable back and forth and right and left, and 3 is tiltable on the movable base 2 in any direction and is an axis. An operation lever (joystick lever) that is mounted so as to be able to rotate around is provided through a three-dimensional drive means (optical system drive means) (not shown) for fine movement operation in the front / rear direction (Z direction) and left / right (X Direction) and an apparatus main body mounted on the movable base 2 so as to be driven up and down (Y direction).
[0013]
As shown in FIG. 8, the three-dimensional driving means includes a pulse motor PM1 for driving the apparatus main body 4 in the vertical direction, a pulse motor PM2 for driving the apparatus main body 4 back and forth, and the apparatus main body 4 in the horizontal direction. A pulse motor PM3 for driving the motor. As the three-dimensional driving means, a vertical movement table that can be driven up and down by a pulse motor PM1, a left and right movement table that can be driven left and right by a pulse motor PM2, is provided on the vertical movement table, and a pulse motor PM3. A structure is provided in which a longitudinally movable table that can be driven back and forth is provided on the laterally movable table.
[0014]
In addition, the apparatus main body 4 is operated to move back and forth and left and right by tilting the operation lever 3 back and forth and right and left, and the pulse motor PM1 by rotating the operation lever 3 clockwise by a predetermined angle around the axis. To move the apparatus body 4 upward, and to rotate the operation lever 3 counterclockwise around the axis to rotate the pulse motor PM1 in the reverse direction to move the apparatus body 4 downward. It is supposed to let you. In the present embodiment, the apparatus main body 4 is moved up and down using the pulse motor PM1 driven by the turning operation around the axis of the operation lever 3. However, the present invention is not necessarily limited to this. . For example, the forward / backward rotation operation around the axis of the operation lever 3 may be converted into vertical power by mechanical interlocking means, and the apparatus main body 4 may be driven up and down by the mechanical interlocking means.
[0015]
The apparatus body 4 detects the alignment of the illumination optical system 100 that illuminates the fundus Er of the eye E, the imaging optical system 200 that captures the illuminated fundus Er, and the eye E shown in FIG. An alignment optical system 400, a focus detection optical system 500 for detecting the focus of the photographing optical system 200, and a fixed finger target optical system 900 are provided.
<Illumination optical system 100>
The illumination optical system 100 includes a ring having a xenon lamp 104 as a photographing light source, a condenser lens 106, a dichroic mirror 108 that transmits visible light and reflects infrared light, and a ring opening 110a at a conjugate position with the pupil Ea. An aperture plate 110, a relay lens 112, a perforated mirror 114, and an objective lens 204 are provided. The illumination optical system 100 includes a halogen lamp 118 that is a light source for observation and photographing, an infrared filter 120 that cuts visible light and transmits only infrared light, and a condenser lens 122.
[0016]
The illumination optical system 100 irradiates the ring aperture plate 110 via the condenser lens 122 and the dichroic mirror 108 with infrared light that is lit by the halogen lamp 118 and transmitted through the infrared filter 120 during fundus observation. The light beam that has passed through the ring opening 110 a of the ring opening plate 110 enters the eye E through the relay lens 112, the perforated mirror 114, the half mirrors 901 and 402, and the objective lens 204. Since the ring aperture plate 110 and the pupil Ea are in a conjugate position, a ring aperture image is formed on the pupil Ea, and the fundus Er is illuminated by this ring aperture image. At the time of fundus photography, the halogen lamp 118 is turned on, the infrared light transmitted through the infrared filter 120 is reflected by the dichroic mirror 108, and the fundus Er is illuminated in the same manner as described above.
<Photographing optical system 200>
The photographing optical system 200 includes an electronic photographing optical system and a film photographing optical system. This electronic photographing optical system includes an objective lens 204, a diaphragm 206 that allows only a light beam that has passed through the center of the pupil Ea of the eye E to be examined, a focusing lens 208, a photographing lens 210, a quick return mirror 306, It has a field lens 218, a relay lens 220, and a mirror 221. The fundus image of the eye to be examined is formed on the area CCD (electronic image pickup means) 224a of the TV camera 224 through the electronic photographing optical system and is picked up. A monitor 226 displays a fundus image 700 captured by the TV camera 224.
[0017]
The film photographing optical system includes an objective lens 204, a diaphragm 206 that allows only a light beam that has passed through the center of the pupil Ea of the eye E to be examined, a focusing lens 208, and a photographing lens 210. And have. Then, when a shutter button (shutter switch) 607 provided on the operation lever 3 in FIG. 10 is pressed, the quick return mirror 306 is flipped up by driving means such as a solenoid (not shown), and the fundus image is shown in the 35 mm camera 302a shown in FIG. The image is formed on the film 302.
<Alignment optical system 400>
The alignment optical system (alignment detection means) 400 includes a half mirror 402, a half mirror 406, a relay lens 408, a mirror 410, a two-hole diaphragm 412, a relay lens 414, and a pinhole 415. 416, a condenser lens 418, and light sources 420 and 422 disposed symmetrically with respect to the optical axis 400a. The alignment optical system 400 has an area sensor 426 disposed on the reflection optical axis 424 of the half mirror 406. The indicator plate 416 and the area sensor 426 are in a conjugate relationship.
[0018]
With this configuration, the light beam 430 emitted from the light source 420 is condensed on the pinhole 415 of the indicator plate 416 by the condenser lens 418, then becomes a parallel light beam by the relay lens 414, and passes through one hole of the two-hole aperture 412. After the image of the pinhole 415 is formed at the image formation point 428, it reaches the cornea Ec of the eye E from an oblique direction through the optical path shown in FIG. Similarly, the light beam 432 emitted from the light source 422 is condensed on the pinhole 415 of the indicator plate 416 by the condenser lens 418, and then becomes a parallel light beam by the relay lens 414 and passes through the other hole of the two-hole aperture 412. Similarly, after an image of the pinhole 415 is formed, the light reaches the cornea Ec of the eye E through the optical path shown in FIG.
[0019]
Here, when the eye E is in the proper position, that is, when the eye cornea Ec is in the proper position, the light beams 430 and 432 are formed so as to form an image of the pinhole 415 at the center of curvature Eo of the eye cornea Ec. Project. Thus, when the eye cornea Ec to be examined is in an appropriate position, the light beams 430 and 432 are specularly reflected on the surface of the cornea Ec, pass through the same optical path as the projection optical path, and the area sensor 426 by the objective lens 204 and the half mirrors 402 and 406. An image of the pinhole 415 is formed at the center of the.
[0020]
As shown in FIG. 2, the area sensor 426 is for detecting the position of the light spot 450 that is the arrival point of the light beam, that is, the distances x1, x2, y1, and y2, and voltage signals x1, x2, y1, and y2 are output. This voltage signal is a signal that is also affected by the amount of light incident on the area sensor 426.
[0021]
FIG. 3 shows the arrival positions of the light beams 430 and 432 on the area sensor 426. The arrival position of the light beam 430 when the light source 420 is turned on is indicated by a circle, and the arrival position of the light beam 430 when the light source 422 is turned on is indicated by a mark. 3A shows that the eye cornea Ec to be examined is displaced from the proper position in the direction of the optical axis 202 (hereinafter referred to as the Z direction), and the eye cornea Ec to be examined is also in the X direction and the Y direction which are perpendicular to the optical axis 202. When the light sources 420 and 422 are alternately turned on, the light beams 430 and 432 alternately reach different positions on the area sensor 426. The distance between the ◯ mark and the .X mark with respect to the X axis corresponds to the amount of shift in the Z direction of the eye cornea Ec to be examined. If the direction of deviation is different with respect to the Z direction, the positions of the ○ and.
FIG. 3B shows a case where the position of the eye cornea Ec to be examined is in an appropriate position with respect to the X direction and the Y direction, and an intermediate position O ′ between the marks ◯ and. Coincides with the center O.
[0022]
FIG. 3C shows a case where the eye cornea Ec to be examined is arranged at appropriate positions in the X direction, the Y direction, and the Z direction. The arrival position of the light beam 430 and the arrival position of the light beam 432 are at the center O of the area sensor 426. Match. At this time, the eye cornea Ec is in an appropriate position, and the eye position adjustment is complete. This state is obtained from a signal output from the area sensor 426 to detect alignment.
<Focus detection optical system 500>
The focus detection optical system 500 is , A reflecting mirror 502 disposed behind the stop 206 on the photographing optical axis 202, a mirror 506 disposed on the reflecting optical axis 504 of the reflecting mirror 502, a relay lens 508, a slit index plate 510, and a condenser lens. 514 and a light source 516. Light from the light source 516 passes through the condenser lens 514 and illuminates the slit indicator plate 510.
[0023]
As shown in FIG. 4a, the slit indicator plate 510 includes slit-like indicators 510a and 510d provided on the YY ′ axis, and slit-like indicators provided in parallel to the indicators 510a and 510d and at the same distance on both sides. Indices 510b and 510c. Deviation prisms 512a, 512b, 512c, and 512d are arranged in close contact with the indicators 510a, 510b, 510c, and 510d, respectively.
[0024]
The declination prisms 512a, 512c, 512c, and 512d give declinations in the directions of a, b, c, and d in the plane including the XX 'axis, as shown in FIG. 4b. The slit transmitted light enters the eye E through the relay lens 508, the mirror 506, the reflecting mirror 502, the aperture 206, the aperture mirror 114, and the objective lens 204. And projected on the fundus .
[0025]
As described above, the reflecting mirror 502 that reflects the slit transmitted light divided in two directions by the declination prism 512 toward the objective lens 204 is arranged symmetrically on both sides of the optical axis as shown in FIG. It consists of a plurality of reflecting portions 502a and 502b. For this reason, the reflecting mirror 502 is reflected by the fundus oculi Er and does not hinder the photographing effective light flux toward the film 302 at all.
[0026]
The diaphragm 206 has a diaphragm hole 206a for the effective photographing light beam at the center and diaphragm holes 206b and 206c for the focus detection light beam on both sides thereof. Further, the perforated mirror 114 also has a hole 113 having a protruding portion 115 on both sides so that the focus detection light beam can pass therethrough.
[0027]
In FIG. 1, the focusing lens 208 of the focusing detection system of the imaging optical system 200, the relay lens 508, the slit index plate 510, the condenser lens 514, and the light source 516 of the focusing detection optical system 500 are integrally photographed. Focusing is performed by moving on the optical axis 202 and the optical axis 504 parallel thereto.
[0028]
By providing the focus detection optical system 500 having the above-described configuration, the monitor television 226 overlaps with the fundus image 700 as shown in FIG. 510 ' Is projected. In-focus state and index image 510 ' Is shown in FIG.
[0029]
FIG. 7a shows an index image at the time of focusing, and FIGS. 7b and 7c show an index image at the time of non-focusing. The dotted lines shown in FIGS. 7b and 7c indicate the position of the index image at the time of focusing.
[0030]
When the index image plane moves on the optical axis with respect to the fundus, Slit-like Index image 510a ′ and Slit-like The index images 510b ′ and 510c ′ move in directions opposite to each other. At the time of focusing, the distance L1 between the index image 510b ′ and the index image 510a ′ is equal to the distance L2 between the index images 510a ′ and 510c ′. That is, L1 and L2 are electrically detected, and the moving direction of the focusing lens 3 is determined by the sign of (L1−L2), and when L1 = L2, it can be detected that the focusing state is achieved.
[0031]
FIG. 8 is a block diagram showing the configuration of the control system of the fundus camera.
[0032]
In FIG. 8, reference numeral 601 denotes a blink detection circuit that detects whether or not the subject blinks from the image signal G output from the TV camera 224. This is because when the subject blinks, the amount of light reflected from the eyelid is much larger than the light reflected from the fundus Er, so that the level of the image signal increases, as shown in FIG. The image signal G1 exceeds the reference level H3.
[0033]
That is, blinking is detected by detecting whether or not the level of the image signal G1 exceeds the reference level H3.
[0034]
Reference numeral 602 denotes a focus detection circuit that obtains the positions of the index images 510a ′ to 510d ′ from the image signal G2 and detects the focus from these positions. Since the image signals Ga of the index images 510a ′ to 510d ′ have a higher luminance level than other fundus portions, the level is higher than a predetermined reference level H2 (H2 <H3). That is, the index images 510a ′ to 510d ′ can be obtained by detecting the image signal Ga that is higher than the reference level H2, and the positions of the index images 510a ′ to 510d ′ are obtained and focused. It is to detect. The focus detection circuit 602 and the focus optical system 500 constitute a focus detection unit.
[0035]
Reference numeral 603 denotes a gaze direction detection circuit that obtains the position of the nipple from the image signal G2 and detects the gaze direction from the position of the nipple. The TV camera 224 and the line-of-sight direction detection circuit constitute a line-of-sight detection means.
[0036]
Since the level of the image signal Gn of the nipple image is higher than that of other fundus tissues, it becomes a predetermined reference level H1 (H1 <H2) or higher. That is, the position of the nipple can be obtained by detecting an image signal Gn which is not less than the reference level H1 and not more than the reference level H2. Further, the signal level of the fundus image is bilaterally symmetric (except for the index images 510a ′ to 510d ′), and is asymmetric in the nipple portion. That is, the signal level of the nipple that is asymmetrical may be found by slicing the image signal G2 sequentially from top to bottom.
[0037]
The position of the nipple image N is the position shown in FIG. 6 when the line-of-sight direction of the eye E and the optical axis 202 of the fundus camera match. When the line-of-sight direction is different from the optical axis 202, the position of the nipple image N also deviates from the position shown in FIG. 6 in accordance with the angle formed by the line-of-sight direction and the optical axis 202. That is, the line-of-sight direction can be detected by obtaining the position of the nipple image N. When the nipple image N is within the predetermined range F, the line-of-sight detection circuit 603 detects that the line-of-sight direction is in the predetermined direction.
[0038]
Reference numeral 604 denotes an alignment detection circuit that detects whether or not the alignment is completed from a signal output from the area sensor 426. That is, as shown in FIG. 3C, it is detected whether or not the mark ◯ that is the arrival position of the light beam 430 and the mark · that is the arrival position of the light beam 432 coincide with the center position of the area sensor 426. The alignment optical system 400 and the alignment detection circuit 604 constitute an alignment detection means.
[0039]
Reference numeral 605 denotes a control device composed of a CPU or the like. This control device 605 is based on the detection signals S1 to S4 detected by the detection circuits 601 to 604 and the operation of the operation switch 606 and the shutter 607 (lens driving means, that is, lens driving). Apparatus) 608, xenon lamp 104, halogen lamp 118, light sources 420, 422, 516, and the like are controlled.
[0040]
The driving device (lens driving means) 608 includes a pulse motor and a gear driving mechanism operated by the pulse motor. The driving device (lens driving means) 608 emits a focusing lens 208, a relay lens 508, a slit index plate 510, a condenser lens 514, and a light source 516. Used to move integrally along the axis. That is, the control device 605 detects that the imaging optical system 200 has entered the focusable range based on the output from the area sensor 426 of the alignment detection circuit 604, controls the operation of the drive device 608, and focuses the focus lens. It also serves as a focusing control means for performing focusing on the fundus Er of the area CCD 224a by 208. The control device 605 also serves as a focus start position correction unit that corrects the focus start position by controlling the operation of the drive device 608 based on the eye refractive power data.
[0041]
In addition, when the area sensor 426 of the alignment detection optical system 400 detects rough alignment with respect to the fundus Er of the photographing optical system 200, the control device 605 controls driving of the pulse motors PM1 to PM3 that are optical system driving means. The automatic alignment control means for automatically controlling the alignment of the fundus of the photographing optical system 200 is also used.
[0042]
In this embodiment, the control device 605 also serves as the focus control means, the focus start position correction means, and the auto alignment control means, but the focus control means, the focus start position correction means, and the auto alignment control means are controlled. It can also be provided separately from the device 605.
[0043]
Reference numeral 609 denotes a display that displays the completion of alignment when the alignment detection circuit 604 detects alignment.
<Finger finger target optical system 900>
The fixation target optical system 900 includes an objective lens 204, half mirrors 402 and 901, a fixation target 902 that is driven and operated in the optical axis direction, a relay lens 903, an aperture 904, and a point light source 905. Moreover, the point light source 905 is substantially conjugate with the pupil Ea on the optical axis P of the fixation target optical system 900 in a state in which the imaging optical system 200 is aligned with the subject's eye cornea (anterior eye portion to be examined) Ec. It is set to be.
[0044]
The fixation target 902 is projected onto the eye E by a paraxial light beam emitted from the point light source 905. In this manner, by providing the stop 904 in front of the point light source 905, only the paraxial light beam emitted from the point light source 905 is projected onto the fixation target 905. Note that the point light source 905 may be blinked so that no adjustment force acts on the eye to be examined.
[0045]
In this fixation target optical system, when the point light source 905 is turned on, the paraxial light beam extracted by the aperture 904 out of the light from the point light source 905 reaches the fixation target 902 via the relay lens 903, thereby The fixation target 902 is projected on the eye E through the objective lens 204 after passing through the half mirrors 901 and 402.
[0046]
In this case, since the opening of the light bundle of the projection image of the fixation target formed on the eye E is small, the projection image has a deep focal depth. Therefore, even if the subject is moderately or intensely myopic or farsighted, the projected image will be watched in a focused state. Therefore, the fixation target 902 is moved in the direction of the optical axis to operate the eye to be examined. E can be in a clouded state.
<Ocular refractive power data input means>
A refractometer RM, a floppy drive 921, an IC card reader 922, and the like are connected to the control device 605 as eye refractive power data input means.
[Operation of Example]
Next, the operation of the above embodiment will be described.
[0047]
First, when a main switch (not shown) is turned on to turn on the fundus camera, the halogen lamp 118 is turned on. When the halogen lamp 118 is turned on, the infrared light from the halogen lamp 118 that has passed through the infrared filter 120 is converted into the condenser lens 122, the dichroic mirror 108, the ring aperture plate 110, the relay lens 112, the aperture mirror 114, the half mirror 901. The image is projected onto the fundus Er of the eye E through 402 and the objective lens 204, and the fundus Er is illuminated.
[0048]
The reflected light from the fundus oculi Er is an electronic photographing optical system, that is, the objective lens 204, the half mirrors 402 and 901, the aperture 113 of the aperture mirror 114, the aperture 206. The fundus image is guided to the TV camera 224 through the focusing lens 208, the imaging lens 210, the quick return mirror 306, the field lens 218, the relay lens 220, and the mirror 2211 to form the fundus image on the area CCD 224a of the TV camera 224. A video signal (output signal) from the area CCD 204 a is input to the monitor 226 via the control device 605, and the fundus image 700 is displayed on the monitor 226.
[0049]
Next, with the power of the fundus camera turned on, the eye refractive power data from the refractometer RM is directly input to the control device 605 via the data input unit 920 or is measured in advance by the refractometer. The eye refractive power data recorded on the floppy desk is read by the floppy drive 921 and inputted to the control device 605, or the eye refractive power data measured in advance by the refractometer and recorded in the IC card reader is used as the IC. The data is read by the card reader 922 or the like and input to the control device 605. As the eye refractive power data, spherical power S is used, but in addition to this, cylindrical axis angle A and cylindrical power C can also be used.
[0050]
If the fundus camera is also used as a refractometer, it is not necessary to input the eye refractive power data. In this case, the operation of the apparatus is controlled according to a preset program so that the fundus is observed and photographed after the eye refractive power is measured.
[0051]
Thereafter, the operation switch 606 is operated so that the light sources 420 and 422 are alternately turned on to start alignment of the apparatus main body 4, that is, the imaging optical system 200 with the eye cornea Ec to be examined. At this time, by alternately guiding the light beams 430 and 432 of the light sources 420 and 422 to the eye E through the alignment optical system 400, the light beams transmitted through the pinholes 415 of the alignment optical system 400 are transmitted to the eye cornea Ec to be examined. Projected. A reflected light beam from the eye cornea Ec due to the alternate lighting of the light sources 420 and 422 is guided to the area sensor 426 via the objective lens 204 and the half mirrors 402 and 406. The output from the area sensor 426 is input to the control device 605 via the alignment detection circuit 604.
[0052]
The control device 605 displays marks 430 a and 432 a indicating the positions of the reflected light from the light beams 430 and 432 so as to overlap the fundus image 700. This mark 430a corresponds to the mark ◯ indicating the arrival position of the light beam 430 on the area sensor 426 shown in FIG. 3, and the mark 432a indicates the arrival position of the light beam 430 on the area sensor 426 shown in FIG. It corresponds. Accordingly, the deviation between the marks 430a and 432a coincides with the deviation between the circle marks and the marks. Therefore, the operation lever 3 is operated while observing the fundus image 700 of the monitor 226 so that the marks 430a and 432a coincide with each other. The alignment operation of the photographing optical system 200 is started.
[0053]
At this time, by tilting the operation lever 3 back and forth and left and right to move the movable table 2 back and forth and left and right, the apparatus body 11 is moved back and forth and left and right, and the operation lever 3 is moved around the axis. The apparatus body 11 is driven up and down by rotating or reversely rotating the pulse motor PM1 in the forward or reverse direction.
[0054]
With this operation, when the marks 430a and 432a approach to a certain extent and enter the auto-alignable range, the control device 605 drives and controls the pulse motors PM1, PM2, and PM3 to automatically move the device body 4 up and down, front and back, and left and right. Start alignment. When the auto-alignment for the eye cornea Ec to be examined is completed, the alignment detection circuit 604 outputs an alignment completion signal Sa, and the display 609 displays completion of alignment.
[0055]
On the other hand, when the imaging optical system 200 is aligned with the eye cornea Ec, the pinhole 415 image is formed at the center of curvature E0 of the eye cornea Ec and the center of the area sensor 426 as described above. The light source 905 is positioned substantially conjugate with the pupil Ea on the optical axis P of the fixation target optical system 900. In addition, when the focusing lens 208 is in alignment and the eye to be examined is a normal eye, the area CCD 224a of the TV camera 224 and the focus detection optical system 500 slit target plate 510 of the eye E to be examined. It is arranged at a position that acts so as to be substantially conjugate with the fundus Er. This position is the initial position of the focusing lens 208. When the main switch is turned on, the control device 605 controls the drive device 608 to place the focusing lens 208 at the initial position.
[0056]
Therefore, the control device 605 does not operate the driving device 608 during the above-described alignment operation and moves the focusing lens 208 to the current state when the input eye refractive power data is data of the range of the normal eye. It has become. Further, the control device 605 does not operate the driving device 608 during the above-described alignment operation even when the eye refractive power data is not input, and positions the focusing lens 208 at the current state.
[0057]
Further, when the input eye refractive power data is not a normal eye but a near-sighted eye or a far-sighted eye, the control device 605 performs the area CCD 224a and the focus detection optical system of the TV camera 224 during the alignment operation as described above. 500 , The driving device 608 is controlled based on the input eye refractive power data so that the slit target plate 510 is substantially conjugated with the fundus Er of the eye E, and the focusing lens 208, the relay lens 508, and the slit index are controlled. The plate 510, the condenser lens 514, the light source 516, and the like are moved together in the optical axis direction of the photographing optical system 200.
[0058]
Then, when the above-described auto alignment is completed, the control device 605 turns on the light source 516 and places the fundus Er on the fundus Er as shown in FIG. Index image 510 ′ Project. TV camera 224 Index image 510 ' Is output as an image signal G2 (see FIG. 9) of the fundus Er.
[0059]
At this time, the focus detection circuit 602 starts from the image signal G2 as shown in FIG. The slit-shaped index image of FIG. The positions 510a 'to 510d' are obtained, and L1 and L2 are obtained from these positions. Based on L1 and L2 obtained by the focus detection circuit 602, the control device 605 drives the drive device 608 so that L1 and L2 coincide with each other, and the focusing lens 208, the relay lens 508, the slit index plate 510, and the condenser lens. 514, the light source 516, etc. are moved.
[0060]
When L1 and L2 coincide with each other by the movement of the focusing lens 208 or the like, that is, when the fundus Er is in focus, the focus detection circuit 602 outputs a focusing signal S2.
[0061]
On the other hand, the line-of-sight direction detection circuit 603 obtains the position of the nipple N (see FIG. 6) from the image signal G2 shown in FIG. 9, and determines whether or not the position of the nipple N is within a predetermined range F. Is within the predetermined range F, the signal S3 is output assuming that the line-of-sight direction is in the predetermined direction.
[0062]
The blink detection circuit 601 detects whether or not the subject blinks from the image signal G2 shown in FIG. 9, and outputs a signal S4 when no blink is detected.
[0063]
Then, the examiner confirms that the subject is in focus while viewing the fundus image 700 displayed on the monitor 226 and presses the shutter 607. When the shutter 607 is pressed, the control device 605 outputs various control signals to cause the xenon lamp 104 to emit light and quickly, on condition that the signals S1 to S4 are output from the detection circuits 601 to 604. The return mirror 306 is lifted to the broken line position. As a result, the fundus image is formed on the film 302 and the fundus image is captured. When the xenon lamp 104 emits light, the light source 516 is turned off, and the slit images 510a ′ to 510d ′ are not photographed.
[0064]
That is, the control device 605 functions as a photographing permission unit that permits photographing.
[0065]
By the way, when the subject blinks or looks away when the shutter 607 is pressed, the signal S4 from the blink detection circuit 601 and the signal S3 from the line-of-sight detection circuit 603 are not output. As a result, the control device 605 is in a prohibition state in which photographing is prohibited, and even if the shutter 607 is pressed, the xenon lamp 104 is not emitted or the quick return mirror 306 is not lifted up. It will not be broken.
[0066]
Therefore, when the subject blinks or looks away, even if the shutter 607 is mistakenly pressed, no imaging is performed, so that the imaging failure is prevented. In addition, even when the user is looking away, the photographing is not executed, so that it is possible to prevent photographing of the fundus other than desired.
[0067]
Further, when any one of the signals S1 to S4 is not output, the control device 605 is in a prohibited state in which photographing is prohibited, so that photographing failure can be reliably prevented and only a desired fundus image is obtained. Can be reliably photographed.
[0068]
In the embodiment described above, when the input eye refractive power data is not a normal eye but a near-sighted eye or a far-sighted eye, the control device 605 performs the alignment of the area CCD 224a of the TV camera 224 and the matching eye during the alignment operation as described above. The driving device 608 is controlled based on the input eye refractive power data so that the focus detection optical system 500 slit target plate 510 is substantially conjugate with the fundus oculi Er of the eye E, and the focusing lens 208 and relay are controlled. The lens 508, the slit indicator plate 510, the condenser lens 514, the light source 516, and the like are integrally moved in the optical axis direction of the photographing optical system 200. However, it is not limited to this.
[0069]
For example, when eye refractive power data is input, the fundus camera (device) is turned on or before the eye to be examined regardless of whether or not the alignment operation is being performed. The area CCD 224a of the TV camera 224 and the focus detection optical system when the alignment with respect to the eye part is started or when any state is detected such as when the fundus camera is completed and the fundus camera is moved away from the eye to be examined. The driving device 608 is controlled based on the inputted eye refractive power data so that the 500-slit target plate 510 is substantially conjugate with the fundus Er of the eye E, and the focusing lens 208, the relay lens 508, and the slit are controlled. The index plate 510, the condenser lens 514, the light source 516, and the like may be moved together in the optical axis direction of the photographing optical system 200.
[0070]
Further, as shown in FIG. 11, the apparatus main body 4 is provided with a focusing knob (focusing handle) 800, and a forward / reverse rotation operation signal of the focusing knob 800 is input to the control device 605 of FIG. The operation of the drive device 608 is controlled by the control device 605 in accordance with the forward / reverse rotation direction and the rotation amount of the focusing knob 800, and the normal eye position is applied to the apparatus main body 4 along the periphery of the focusing knob 800. Reference marks 801, + a (diopter), -a (diopter) scale 802, and the alignment mark 803 of the focusing knob 800 according to the eye refractive power data of the subject's eye, the reference mark 801, + a (diopter). ), -A (diopter) scale 803 so that the focus knob 800 may be rotated (manually operated).
[0071]
【The invention's effect】
As described above, the invention according to claim 1 controls the photographing optical system provided with the focusing lens for focusing the imaging means to the fundus of the eye to be inspected, and controls the driving of the focusing lens in the optical axis direction. A fundus camera comprising a lens driving means, a data input means for inputting eye refractive power data of the eye to be examined; and an operation control of the lens driving means based on the eye refractive power data to determine a focus start position. Since the focus start position correcting means for correcting is provided, the imaging device can always be focused on the fundus in a short time regardless of the eye refractive power of the eye to be examined.
[0072]
Also , Alignment detecting means for detecting alignment of the photographing optical system with respect to the fundus, optical system driving means for driving the photographing optical system in a three-dimensional direction, and the alignment detecting means for performing rough alignment with respect to the fundus of the photographing optical system. Auto-alignment control means for automatically controlling the alignment of the photographing optical system with respect to the fundus oculi when the optical system drive means is detected. During the alignment control operation by the alignment control means, the lens driving means is controlled based on the eye refractive power data to correct the focus start position. Focusing work can be done in time.
[Brief description of the drawings]
FIG. 1 is an optical arrangement diagram showing the configuration of a fundus camera according to the present invention.
FIG. 2 is an explanatory diagram showing an area sensor.
FIG. 3A is an explanatory diagram showing a light flux arrival point when the eye cornea to be examined is displaced in the X, Y, and Z axis directions from an appropriate position. B is an explanatory diagram showing a light beam arrival point when the eye cornea to be examined is displaced from the proper position in the Z-axis direction. C is an explanatory view showing a light flux arrival point when the eye cornea to be examined is at an appropriate position.
FIG. 4A is a perspective view showing a slit index plate. b is an explanatory view showing the declination direction.
FIG. 5 is an explanatory diagram showing a configuration of a focus detection optical system.
FIG. 6 is an explanatory diagram showing a fundus image.
FIG. 7 is an explanatory diagram showing a relationship between an in-focus state and an index image, and a is an explanatory diagram showing a position of the index image at the time of focusing. b is an explanatory diagram showing the position of the index image when the focus is out of focus. c is an explanatory diagram showing the position of the index image when the focus is out of focus.
FIG. 8 is a block diagram showing a configuration of a control system of the fundus camera.
FIG. 9 is an explanatory diagram of an image signal.
10 is a side view of a fundus camera including the optical system shown in FIG. 1. FIG.
FIG. 11 is an explanatory view showing another embodiment of the present invention.
[Explanation of symbols]
200: Photography optical system
224 ... TV camera
224a Area CCD (imaging means)
208 ... Focus lens
400 ... alignment optical system
500 ... Focus detection optical system
602... Focus detection circuit
604 ... Alignment detection circuit (alignment detection means)
605... Control device (focus control means, focus start position correction means, auto alignment control means)
PM1 to PM3 ... pulse motor (optical system drive means)
608 ... Driving device (lens driving means)
E ... Eye to be examined
Er ... Er

Claims (3)

An imaging optical system focusing focusing lens is provided for the imaging unit of the fundus, and a lens driving means for driving and controlling the focusing lens in the optical axis direction, said eye to be examined eye refractive power data a data input means for inputting a focus start position correcting means for correcting the focus start position operate controlling the lens driving means on the basis of the eye refractive power data, the alignment with respect to the fundus of the imaging optical system Alignment detecting means for detecting, optical system driving means for driving the photographing optical system in a three-dimensional direction, and the optical system driving means when the alignment detecting means detects rough alignment of the photographing optical system with respect to the fundus A fundus camera comprising: an auto-alignment control unit that controls the driving of the photographing optical system and automatically controls the alignment of the fundus .
The focus start position correcting means is set to correct the focus start position by operating the lens driving means based on the eye refractive power data during the alignment control operation by the auto alignment control means. fundus camera, characterized by that.   The fundus camera according to claim 1, further comprising a control device that performs focusing by controlling the lens driving unit when the alignment by the auto-alignment control unit is completed. 2. The fundus camera according to claim 1, wherein a slit transmitted light beam, which is light from a light source and transmitted through a slit-shaped index of a slit index plate, is incident on the eye to be examined, and a slit-shaped index image is projected on the fundus. Equipped with an in-focus detection optical system,
The focusing start position correcting means controls the lens driving means based on the eye refractive power data to light the focusing lens and the slit indicator plate during the alignment control operation by the auto alignment control means. It is set to correct the focus start position by controlling the drive integrally in the axial direction ,
When the alignment by the auto-alignment control unit is completed, the control device turns on the light source to project the plurality of slit transmitted light beams onto the fundus and takes the slit image by the plurality of slit transmitted light beams An image is formed on the imaging unit through an optical system, and the focusing lens and the slit indicator plate are lighted by the driving device in a direction in which the imaging unit is focused on the fundus based on an image signal of the imaging unit. A fundus camera that is integrally driven and controlled in the axial direction .

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