JP2000116603A - Retinal camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish the focusing of an image sensor in a short time regardless of ocular refractivity of eyes to be examined by operating or controlling a lens drive means based on the ocular refractivity of the eyes to be examined to allow the correction of the position of starting focusing in a type equipped with a focusing lens in a photographing optical system for photographing the eyegrounds of the eyes to be examined. SOLUTION: A lens driver 608 or the like is controlled by a controller 605 based on detection signals S1-S4 of a nictitation detection circuit 601, a focusing detection circuit 602, an eye sight direction detection circuit 603 and an alignment detection circuit 604 and the operation of an operation switch 606 and a shutter 607. The lens driver 608 is so arranged as to move a focusing lens, a relay lens and the like integrally along an optical axis with a pulse motor as a drive source. In this process, the lens driver 608 is controlled based on an ocular refractivity data of eyes to be examined inputted by a data input means to correct the position of starting focusing with the focusing lens thereby enhancing operability in the focusing of an image sensor on the eyegrounds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera provided with a focusing lens in a photographing optical system for photographing the fundus of a subject's eye.

[0002]

2. Description of the Related Art A fundus camera provided with an illumination optical system for illuminating the fundus of an eye to be examined and a photographing optical system for photographing the fundus has been known.

Such a fundus camera includes a photographing optical system and an anterior eye observation optical system for photographing an anterior eye and a fundus of an eye to be inspected in order to photograph a fundus image in which an observation optical system is suitable for an alignment optical system. The camera is provided so that it can be photographed by the image sensor of the TV camera, and the anterior segment of the eye to be inspected is photographed by the image sensor via the anterior eye observation optical system. While the imaging optical system was aligned with the anterior ocular segment of the subject's eye, the fundus of the subject's eye was imaged with the imaging device via the imaging optical system by switching from anterior ocular segment observation to fundus observation. In some cases, the fundus is observed and photographed on a monitor TV.

[0004]

However, in such a fundus camera, it is not possible to know the sharpness of the captured fundus until switching from observation of the anterior eye to observation of the fundus.

[0005] In order to solve this problem, a fundus camera in which the focusing lens is controlled to move in the optical axis direction after the alignment with respect to the eye to be inspected is performed with respect to the fundus, and the imaging device focuses on the fundus. Is considered.

However, since the amount of movement control of the focusing lens differs depending on the eye refractive power of the eye to be examined, there is a problem that a person having a large eye refractive power takes time to focus.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fundus camera capable of always focusing an imaging device on a fundus in a short time regardless of the magnitude of the eye refractive power of the eye to be examined.

[0008]

In order to achieve the above object, the present invention is directed to a photographing optical system provided with a focusing lens for focusing an image pickup means on a fundus of an eye to be inspected. A fundus camera having lens driving means for driving and controlling a focusing lens in an optical axis direction, wherein the data driving means inputs eye refractive power data of the eye to be examined, and the lens driving means based on the eye refractive power data And a fundus camera provided with a focus start position correcting means for correcting the focus start position by controlling the operation of the camera.

According to a second aspect of the present invention, there is provided an alignment detecting means for detecting an alignment of the photographing optical system with respect to the fundus, an optical system driving means for driving the photographing optical system in a three-dimensional direction, and the alignment detecting means comprises: When detecting rough alignment of the photographing optical system with respect to the fundus, the apparatus includes drive control of the optical system driving means, and automatic alignment control means for performing automatic control of alignment of the photographing optical system with respect to the fundus, and The focus start position correcting means is set to correct the focus start position by controlling the operation of the lens driving means based on the eye refractive power data during the alignment control operation by the automatic alignment control means. It is characterized by being.

According to a third aspect of the present invention, the in-focus start position correcting means controls the operation of the lens driving means when there is no eye refractive power data, so that the in-focus lens is positioned at the position of the emmetropic eye when the alignment is completed. Is set to be located at

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fundus camera according to the present invention will be described below with reference to the drawings.

In FIG. 10, 1 is a fixed base of a fundus camera, 2 is a movable base (a stand) mounted on the fixed base 1 so as to be movable back and forth and left and right, and 3 is a tilting operation of the movable base 2 in an arbitrary direction. The operation lever (joystick lever), which is mounted so as to be rotatable around the axis, can be moved back and forth (Z direction) via a three-dimensional driving means (optical system driving means) (not shown) for fine movement operation. The apparatus main body is mounted on the movable base 2 so as to be able to be driven left and right (X direction) and up and down (Y direction).

As shown in FIG. 8, the three-dimensional driving means includes a pulse motor PM1 for driving the apparatus body 4 in the vertical direction, a pulse motor PM2 for driving the apparatus body 4 back and forth, Has a pulse motor PM3 for driving the motor in the left-right direction. As the three-dimensional driving means, a vertical movement table which can be driven up and down by a pulse motor PM1 is provided, a left and right movement table which can be driven left and right by a pulse motor PM2 is provided on the vertical movement table, and a pulse motor PM3 is provided. It employs a structure in which a front-rear table that can be driven forward and backward is provided on the left-right table.

Further, 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 left and right, and by rotating the operation lever 3 clockwise around the axis by a predetermined angle. The pulse motor PM1 is driven to move the apparatus main body 4 upward, and the operation lever 3 is rotated counterclockwise by a predetermined angle around the axis to drive the pulse motor PM1 in the reverse direction to drive the apparatus main body 4 to rotate. It is designed to move downward. In this embodiment,
The apparatus main body 4 is moved up and down by using the pulse motor PM1 driven by the rotation operation of the operation lever 3 around the axis, but the invention is not necessarily limited to this. For example, a configuration may be employed in which the forward / reverse rotation operation of the operation lever 3 about the axis is converted into vertical power by mechanical interlocking means, and the apparatus main body 4 is driven up and down by the mechanical interlocking means.

The apparatus main body 4 includes an illumination optical system 100 for illuminating the fundus Er of the eye E, a photographing optical system 200 for photographing the illuminated fundus Er, and an eye E shown in FIG.
Optical system 400 for detecting alignment
And a focus detection optical system 500 for detecting the focus of the photographing optical system 200 and a fixed finger target optical system 900. <Illumination optical system 100> The illumination optical system 100 includes a xenon lamp 104, which is a light source for photographing, and a condenser lens 10
6, a dichroic mirror 108 that transmits visible light and reflects infrared light, a ring opening plate 110 having a ring opening 110a at a position conjugate to the pupil Ea, a relay lens 112, a perforated mirror 114, and an objective lens. 204. The illumination optical system 100 includes a halogen lamp 118 as 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.

The illumination optical system 100 illuminates the ring aperture plate 110 via the condenser lens 122 and the dichroic mirror 108 when the halogen lamp 118 is turned on and the infrared light transmitted through the infrared filter 120 is used during fundus observation. The light beam that has passed through the ring opening 110a of the ring opening plate 110 enters the eye E through the relay lens 112, the aperture mirror 114, the half mirrors 901 and 402, and the objective lens 204. Ring aperture plate 110 and pupil Ea
Is located at the conjugate position, a ring opening image is formed on the pupil Ea, and the fundus Er is illuminated by the ring opening image. At the time of fundus photography, the halogen lamp 118
Lights up, the infrared light transmitted through the infrared filter 120 is reflected by the dichroic mirror 108, and illuminates the fundus Er in the same manner as described above. <Shooting Optical System 200> The shooting optical system 200 includes an electronic shooting optical system and a film shooting optical system. The electronic photographing optical system includes an objective lens 204, an aperture 206 that passes only a light beam that has passed through the center of the pupil Ea of the eye E, 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. A fundus image of the subject's eye is displayed in the area C of the TV camera 224 via the electronic photographing optical system.
An image is formed on a CD (electronic imaging means) 224a. A monitor 226 displays a fundus image 700 captured by the TV camera 224.

The film photographing optical system includes an objective lens 204, an aperture 206 for passing only a light beam passing through the center of the pupil Ea of the eye E, a focusing lens 208,
It has a taking lens 210. And having. And
When a shutter button (shutter switch) 607 provided on the operation lever 3 in FIG.
Reference numeral 06 is flipped up by a driving means such as a solenoid (not shown), and a fundus image is formed on the film 302 of the 35 mm camera 302a shown in FIG. <Alignment Optical System 400> The alignment optical system (alignment detection unit) 400 includes a half mirror 402.
, Half mirror 406, relay lens 408, mirror 410, two-hole stop 412, relay lens 414
And an index plate (index) 416 having a pinhole 415
And a condenser lens 418, and light sources 420 and 422 arranged symmetrically with respect to the optical axis 400a.
The alignment optical system 400 includes a half mirror 406
Has an area sensor 426 disposed on the reflected optical axis 424 of the optical disk. Then, the index plate 416 and the area sensor 42
6 has a conjugate relationship.

With this configuration, the light beam 430 emitted from the light source 420 is transmitted to the index plate 4 by the condenser lens 418.
After focusing on the 16 pinholes 415, the relay lens 414
After passing through one of the apertures of the two-hole stop 412 to form an image of the pinhole 415 at the image forming point 428, the light passes through the optical path shown in FIG. Reach from the direction. Similarly, the light beam 432 emitted from the light source 422 is transmitted by the condenser lens 418 to the index plate 4.
After focusing on the 16 pinholes 415, the relay lens 414
After passing through the other hole of the two-hole stop 412 to form an image of the pinhole 415 in the same manner as described above, the light flux passes through the optical path shown in FIG. It arrives from an oblique direction opposite to 430.

Here, when the eye E to be examined is at the proper position, that is, when the cornea Ec to be examined is at the proper position, the light flux 430 is formed so as to form an image of the pinhole 415 at the center of curvature Eo of the cornea Ec to be examined. , 432 are projected. This allows
When the cornea Ec to be examined is at an appropriate position, each light beam 43
Numerals 0 and 432 are specularly reflected on the surface of the cornea Ec, pass through the same optical path as the projection optical path, and pass through the objective lens 204 and the half mirror 4.
02 and 406 form an image of the pinhole 415 at the center of the area sensor 426.

As shown in FIG. 2, the area sensor 426 detects the position of the light spot 450, which is the arrival point of the light beam, that is, the distances x1, x2, y1, and y2. The signals x1, x2, y1, and y2 are output. Note that this voltage signal is a signal that is also affected by the amount of light incident on the area sensor 426.

FIG. 3 shows the arrival positions of the light beams 430 and 432 on the area sensor 426. The arrival position of the light flux 430 when the light source 420 is turned on is indicated by a circle, and the light source 422
The arrival position of the light beam 430 when is turned on is indicated by a mark. FIG. 3A shows that the cornea Ec is displaced from the appropriate position in the direction of the optical axis 202 (hereinafter referred to as the Z direction) and the cornea Ec
This shows a case where c is also deviated in the X direction and the Y direction which are perpendicular to the optical axis 202. When the light sources 420 and 422 are turned on alternately, the light fluxes 430 and 432 are alternately placed at different positions on the area sensor 426. To reach. ○ to X axis
The distance between the mark and the mark corresponds to the amount of displacement of the cornea Ec to be examined in the Z direction. In addition, when the direction of the displacement is different with respect to the Z direction, the positions of the circles and the marks are reversed. FIG.
Indicates a case where the position of the light beam is at an appropriate position in the X direction and the Y direction.
The middle position O 'between the mark and the mark is the center O of the area sensor 426.
Matches.

FIG. 3C shows a case where the cornea Ec to be examined is disposed at an appropriate position in the X, Y, and Z directions. The arrival position of the light beam 430 and the arrival position of the light beam 432 are determined by the area sensor 426. It matches the center O. At this time, the eye cornea Ec is at a proper 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>
A reflecting mirror 502 arranged behind the stop 206 on the photographing optical axis 202, a mirror 506 arranged 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.

As shown in FIG. 4A, the slit index plate 510 has a slit-like index 510 provided on the YY 'axis.
a, 510d, and slit-like indices 510 provided in parallel with and parallel to the indices 510a, 510d at the same distance from each other.
b, 510c. Indices 510a, 510b, 510c,
Deflection prisms 512a, 512b, and 512 are provided at 510d, respectively.
c, 512d are arranged in close contact.

Deflection prisms 512a, 512c, 512c, 5
As shown in FIG. 4B, 12d gives a declination in the directions of a, b, c and d in a plane including the XX 'axis. The light transmitted through the slit is transmitted to the relay lens 508 and the mirror 50.
6. The light enters the eye E via the reflecting mirror 502, the aperture 206, the aperture mirror 114, and the objective lens 204.

As described above, the light transmitted through the slit divided in two directions by the deflection prism 512 is
As shown in FIG. 5, a reflecting mirror 502 that reflects light toward
Two reflecting portions 502a, 502 symmetrically arranged on both sides of the optical axis
02b. Therefore, the reflecting mirror 502 does not hinder the effective luminous flux reflected by the fundus Er toward the film 302 at all.

The aperture 206 has a central aperture 206a for the effective photographing light beam, and two apertures 2 on both sides for the focus detection light beam.
06b, 206c. Further, a perforated mirror 11
4 also has holes 113 with overhangs 115 on both sides to allow the focus detection light beam to pass through.

In FIG. 1, the focusing lens 208 of the focusing detection system of the imaging optical system 200 and the focusing detection optical system 50
The zero relay lens 508, the slit index plate 510, the condenser lens 514, and the light source 516 move together on the photographing optical axis 202 and on the optical axis 504 parallel thereto to perform focusing.

By providing the focus detection optical system 500 having the above configuration, an index image 802 is displayed on the monitor television 226 so as to overlap the fundus image 700 as shown in FIG. FIG. 7 shows the relationship between the in-focus state and the index image 802.

FIG. 7A shows an in-focus target image, and FIGS. 7B and 7C show out-of-focus index images. 7b and 7c
Indicates the position of the target image at the time of focusing.

When the index image plane moves on the optical axis with respect to the fundus, the index image 510a 'and 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' and the index image 5
The interval L2 between 10a 'and 510c' becomes equal. That is, L1 and L2 are electrically detected, the moving direction of the focusing lens 3 is determined by the sign of (L1-L2), and it can be detected that L1 = L2 and the focusing state is established.

FIG. 8 is a block diagram showing the configuration of the control system of the fundus camera.

In FIG. 8, reference numeral 601 denotes a TV camera 224.
Is a blink detection circuit for detecting whether or not the subject has blinked from the image signal G output by the control unit. This is because, when the subject blinks, the amount of reflected light from the eyelid is much larger than the amount of reflected light from the fundus Er, so that the level of the image signal increases, and as shown in FIG. Is higher than the reference level H3.

That is, blinking is detected by detecting whether or not the level of the image signal G1 has exceeded the reference level H3.

Reference numeral 602 denotes an index image 510a from the image signal G2.
This is a focus detection circuit that determines the positions of 'to 510d' and detects focus from these positions. Index images 510a 'to 510d'
Is higher in luminance level than the other fundus portions, and thus has a higher level 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 having a level higher than the reference level H2, and the positions of the index images 510a 'to 510d' are obtained for focusing. It is to detect. The focus detection circuit 602 and the focus optical system 500 constitute a focus detection unit.

Reference numeral 603 denotes a line-of-sight direction detecting circuit for determining the position of the nipple from the image signal G2 and detecting the line-of-sight direction from the position of the nipple. Then, the TV camera 224 and the line-of-sight direction detection circuit constitute a line-of-sight detection unit.

Since the level of the image signal Gn of the nipple image is higher than other fundus tissues, a predetermined reference level H1 (H1 <H
2) Above. That is, the position of the nipple can be determined by detecting the image signal Gn that is equal to or higher than the reference level H1 and equal to or lower than the reference level H2. In addition, the signal levels of the fundus images are bilaterally symmetric (index images 510a ′ to 51d).
0d '), and becomes asymmetric at the nipple. That is,
By slicing the image signal G2 sequentially from top to bottom, the signal level of the asymmetric nipple may be searched for and obtained.

The position of the nipple image N is as shown in FIG. 6 when the line of sight of the eye E and the optical axis 202 of the fundus camera coincide. When the line of sight is directed in a direction different from the optical axis 202, the position of the nipple image N is shifted from the position shown in FIG. 6 in accordance with the angle between the line of sight 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 direction detection circuit 603 detects that the line-of-sight direction is in the predetermined direction.

Reference numeral 604 denotes an alignment detection circuit for detecting whether or not alignment has been completed based on a signal output from the area sensor 426. That is, as shown in FIG. 3C, the mark ○ indicating the arrival position of the light beam 430 and the light beam 432
It is to detect whether or not the mark ".", Which is the arrival position of the object, coincides with the center position of the area sensor 426. The alignment optical system 400 and the alignment detection circuit 604 form an alignment detection unit.

Reference numeral 605 denotes a control device including a CPU and the like.
The control device 605 controls the driving device (lens driving means or lens driving device) 608 and the xenon lamp 10 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.
4, for controlling the light emission of the halogen lamp 118 and the light sources 420, 422, 516.

This driving device (lens driving means) 608
Is provided with a pulse motor and a gear drive mechanism operated by the same, and moves the focusing lens 208 and the relay lens 508, the slit index plate 510, the condenser lens 514, and the light source 516 integrally along the optical axis. Used for That is, the control device 605 detects that the photographing 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 driving device 608, and controls the focusing lens. The focus control unit 208 also focuses on the fundus Er of the area CCD 224a by the area CCD 224a. Also,
The control device 605 controls the driving device 60 based on the eye refractive power data.
8 also serves as a focusing start position correcting means for correcting the focusing start position by controlling the operation.

In addition, the controller 605 determines that the area sensor 426 of the alignment detection optical system 400
When the coarse alignment with respect to the fundus Er of No. 00 is detected, the pulse motors PM1 to PM3 serving as the optical system driving means are detected.
, And also serves as an automatic alignment control means for automatically controlling the alignment of the photographing optical system 200 with respect to the fundus.

In this embodiment, the control device 605 also serves as the focus control means, the focus start position correcting means, and the auto alignment control means. The means is a control device 605
Alternatively, it can be provided separately.

Reference numeral 609 denotes a display for displaying the completion of the alignment when the alignment detecting circuit 604 detects the alignment. <Fixation target optical system 900> The fixation target optical system 900 includes an objective lens 204, half mirrors 402 and 901, a fixation target 902 driven and operated in the optical axis direction, a relay lens 903,
An aperture 904 and a point light source 905 are provided. Moreover, the point light source 9
05 is a state where the imaging optical system 200 is aligned with the cornea Ec (the anterior segment of the eye to be examined) Ec,
The pupil Ea is set at a position substantially conjugate with the pupil Ea on the optical axis P of the fixation target optical system 900.

The fixation target 902 is projected onto the eye E by paraxial rays emitted from the point light source 905. In this way, the stop 9 is provided before the point light source 905.
By providing the light source 04, only paraxial rays emitted from the point light source 905 are projected on the fixation target 905. Note that the point light source 905 may be turned on and off so that the adjusting force does not act on the subject's eye.

In this fixation target optical system, when the point light source 905 is turned on, paraxial rays of the light from the point light source 905 extracted by the stop 904 reach the fixation target 902 via the relay lens 903. Thereby, after the fixation target 902 passes through the half mirrors 901 and 402, the objective lens 20
The light is projected on the eye E through the eye 4.

In this case, the projection image of the fixation target formed on the subject's eye E has a small divergence of light beams, so that the projection image has a large depth of focus. Therefore, even if the subject has moderate or intense myopia or hyperopia, he or she will gaze at the projected image in a focused state. E can be brought into the cloud fogging state. <Eye Refractive Power Data Input Means> The refractometer RM, the floppy drive 921, the IC card reader 922, and the like are connected to the control device 605 as eye refractive power data input means. [Operation of Embodiment] Next, the operation of the above embodiment will be described.

First, when a power switch of the fundus camera is turned on by turning on a main switch (not shown), the halogen lamp 1 is turned on.
18 lights up. When the halogen lamp 118 is turned on, the halogen lamp 11 transmitted through the infrared filter 120 is turned on.
The infrared light from 8 is supplied to the condenser lens 122, the dichroic mirror 108, the ring aperture plate 110, the relay lens 112, the aperture mirror 114, and the half mirror 901.4.
02 and the fundus Er of the eye E through the objective lens 204
And the fundus Er is illuminated.

The light reflected from the fundus Er is transmitted to the electronic photographing optical system, that is, the objective lens 204, the half mirrors 402, 9
01, aperture 113 of aperture mirror 114, aperture 206. Focusing lens 208, imaging lens 210, quick return mirror 306, field lens 218, relay lens 22
0, guided by the TV camera 224 via the mirror 2211, and the fundus image is transferred to the area CCD 224 of the TV camera 224.
An image is formed on a. The video signal (output signal) from the area CCD 204a is sent to the monitor 2 via the control device 605.
The fundus image 700 is displayed on the monitor 226.

Next, while the power of the fundus camera is 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 read by a floppy drive 921 and input to the control device 605, or the eye refractive power data measured by the
The eye refractive power data recorded in the card reader is read by an IC card reader 922 or the like and input to the control device 605. As the eye refractive power data, the spherical power S is used, but in addition, the cylindrical axis angle A and the cylindrical power C can also be used.

If the fundus camera is configured to also have the function of a refractometer, it is not necessary to input the eye refractive power data. In this case, the operation of the apparatus is controlled in accordance with a preset program so as to observe and photograph the fundus after measuring the eye refractive power.

Thereafter, the operation switches 606 are operated to alternately turn on the light sources 420 and 422, and the alignment of the apparatus main body 4, ie, the photographing optical system 200, with respect to the cornea Ec of the eye to be examined is started. At this time, the luminous flux 43 of the light sources 420 and 422
The light flux transmitted through the pinhole 415 of the alignment optical system 400 is projected onto the cornea Ec of the eye to be inspected by alternately guiding 0,432 to the eye E through the alignment optical system 400. The reflected light flux from the cornea Ec to be examined due to the alternate lighting of the light sources 420 and 422 is reflected by the objective lens 2
04, and is guided to the area sensor 426 via the half mirrors 402 and 406. The output from the area sensor 426 is sent to the controller 6 via the alignment detection circuit 604.
05 is input.

The control device 605 controls the light fluxes 430 and 43
Marks 430a and 432a indicating the positions of the reflected light
Is superimposed on the fundus image 700 and displayed. This mark 430a
Corresponds to the mark 印 indicating the arrival position of the light beam 430 on the area sensor 426 shown in FIG. 3, and the mark 432a corresponds to the mark indicating the arrival position of the light beam 430 on the area sensor 426 shown in FIG. I have. Therefore, the marks 430a, 43
Since the deviation of 2a coincides with the state of the deviation between the mark and the mark,
By operating the operation lever 3 while observing the fundus image 700 on the monitor 226, the alignment operation of the photographing optical system 200 is started in the direction where the marks 430a and 432a coincide.

At this time, the operation lever 3 is tilted back and forth and left and right to move the movable table 2 back and forth and left and right, thereby moving the apparatus main body 11 back and forth and left and right and moving the operation lever 3 along the axis. By rotating the pulse motor PM1 forward or backward by rotating it forward or backward, the apparatus main body 11 is driven up and down.

With this operation, marks 430a, 432
When a approaches to a certain extent and enters the auto-alignable range, the control device 605 issues pulse motors PM1, PM2,
The automatic alignment for finely moving the apparatus main body 4 up and down, front and rear, and left and right by controlling the drive of the PM 3 is started. When the auto alignment with respect to the cornea Ec is completed, the alignment detection circuit 604 outputs an alignment completion signal Sa.
Is output, and the display 609 indicates that the alignment is completed.

On the other hand, when the imaging optical system 200 is aligned with the cornea Ec to be examined, an image of the pinhole 415 is formed at the center of curvature E0 of the cornea Ec and the center of the area sensor 426 as described above. Then, the point light source 905 is substantially conjugate with the pupil Ea on the optical axis P of the fixation target optical system 900. Moreover, the focusing lens 208
Is the time when the alignment is correct, and when the eye to be inspected is the emmetropic eye, the area CCD2 of the TV camera 224
24a and focus detection optical system 500 slit optotype plate 510
Is disposed at a position that acts so as to be substantially conjugate with the fundus Er of the eye E to be examined. This position is the initial position of the focusing lens 208. When the main switch is turned on, the control device 605 controls the operation of the driving device 608 to arrange the focusing lens 208 at the initial position.

Accordingly, when the input eye refractive power data is data of the range of the emmetropic eye, the control device 605 does not operate the driving device 608 during the above-described alignment work.
The focusing lens 208 is located at the current position.
Further, even when the eye refractive power data has not been input, the control device 605 also controls the driving device 6 during the above-described alignment work.
08 is not operated, and the focusing lens 208 is positioned at the current position.

Further, when the input eye refractive power data is not myopic eyes but myopic eyes or hyperopic eyes, the control device 605 controls the TV camera 22 during the alignment operation as described above.
The driving device 60 based on the input eye refractive power data such that the area CCD 224a of No. 4 and the focus detection optical system 500 slit optotype plate 510 are substantially conjugate with the fundus Er of the eye E to be examined.
8 to control the focusing lens 208 and the relay lens 5.
08, slit index plate 510, condenser lens 51
4. The light source 516 and the like are integrally moved in the optical axis direction of the photographing optical system 200.

When the above-described auto alignment is completed, the controller 605 turns on the light source 516,
A slit image 802 is projected on the fundus Er as shown in FIG. The TV camera 224 outputs an image signal G2 (see FIG. 9) of the fundus Er onto which the slit image 802 is projected.

At this time, the focus detection circuit 602 detects the slit images 510a 'to 510 from the image signal G2 as shown in FIG.
The position of d 'is obtained, and L1 and L2 are obtained from this position. The control device 605 drives the driving device 608 based on L1 and L2 obtained by the focus detection circuit 602 so that L1 and L2 coincide with each other, so that the focus lens 208, the relay lens 508, the slit index plate 510, and the condenser lens 514, light source 51
6 and so on.

When the focus lens 208 and the like move to make L1 and L2 coincide, that is, when the fundus Er is in focus, the focus detection circuit 602 outputs a focus signal S2.

On the other hand, the line-of-sight direction detection circuit 603 determines 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 the predetermined range F. If the nipple N is within the predetermined range F, the line-of-sight direction is determined to be in the predetermined direction, and the signal S3 is output.

The blink detection circuit 601 detects from the image signal G2 shown in FIG. 9 whether the subject has blinked, and outputs a signal S4 when no blink is detected.

Then, the examiner confirms that the subject is in focus while watching 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 quick light on condition that the respective signals S1 to S4 are output from the respective detection circuits 601 to 604. The return mirror 306 is flipped up to the position indicated by the broken line. Thereby, the fundus image is formed on the film 302, and the fundus image is photographed. When the xenon lamp 104 emits light, the light source 516 is turned off,
The slit images 510a 'to 510d' are not photographed.

That is, the control device 605 functions as a photographing permitting means for permitting photographing.

By the way, when the shutter 607 is pressed,
When the subject blinks or looks away, the blink detection circuit 601 outputs a signal S4 or a line-of-sight direction detection circuit 603.
No longer outputs the signal S3. As a result, the control device 605 enters a prohibition state in which photographing is prohibited, and the shutter 6
Even if 07 is pressed, the xenon lamp 104 does not emit light or the quick return mirror 306 does not flip up, so that no photographing is performed and no fundus image is photographed.

Therefore, when the subject blinks or looks aside, the photographing is not performed even if the shutter 607 is pressed by mistake, so that the photographing failure is prevented. In addition, since the photographing is not performed even when the user is looking away, it is possible to prevent the photographing of the fundus other than desired.

When any one of the signals S1 to S4 is not output, the control device 605 enters a prohibition state in which the photographing is prohibited. Only the fundus image can be reliably photographed.

In the embodiment described above, the control device 605
If the input eye refractive power data is not myopic eyes but myopic or hyperopic eyes, during the alignment work as described above,
The area CCD 224a of the TV camera 224 and the in-focus detection optical system 500 slit optotype plate 510 are located on the fundus E of the eye E to be inspected.
The operation of the driving device 608 is controlled based on the inputted eye refractive power data so that the focusing lens 208, the relay lens 508, the slit index plate 510, the condenser lens 514, the light source 516, etc. The photographing optical system 20 integrally
It is made to move in the optical axis direction of 0. However, it is not limited to this.

For example, when the eye refractive power data is input, the power of the fundus camera (apparatus) is turned on or the power of the fundus camera (apparatus) is turned on regardless of whether the alignment work is in progress. The area CCD 2 of the TV camera 224 is detected when alignment with the anterior segment of the subject's eye is started, or when any state such as when the fundus imaging is completed and the fundus camera is separated from the subject's eye is detected.
24a and focus detection optical system 500 slit optotype plate 510
Is controlled based on the input eye refractive power data so that is substantially conjugate with the fundus Er of the eye E to be examined.
The focusing lens 208, the relay lens 508, the slit index plate 510, the condenser lens 514, the light source 516, and the like may be integrally moved in the optical axis direction of the photographing optical system 200.

Also, as shown in FIG. 11, a focusing knob (focusing handle) 800 is provided on the apparatus main body 4, 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 driving device 608 is controlled by the control device 605 according to the forward / reverse rotation direction and the amount of rotation of the focusing knob 800, and the driving device 608 is moved along the periphery of the focusing knob 800 to the apparatus main body 4. Reference marks 801 and + a at emmetropic eye position
(Diopter), -a (diopter) scale 802, and a focusing knob 800 according to the eye refractive power data of the subject's eye.
The focus knob 800 is rotated (manual operation) so that the alignment mark 803 of the reference mark 801 is aligned with the scale 803 of the reference mark 801, + a (diopter), and -a (diopter).
You may.

[0071]

As described above, according to the first aspect of the present invention, there is provided a photographing optical system provided with a focusing lens for focusing an image pickup means on the fundus of an eye to be inspected, and an optical axis including the focusing lens. A fundus camera provided with lens driving means for driving control in a direction, 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. Since the focus start position correcting means for correcting the focus start position is provided, the image sensor can always be focused on the fundus in a short time regardless of the magnitude of the eye refractive power of the eye to be inspected.

The invention according to claim 2 is an alignment detecting means for detecting alignment of the photographing optical system with respect to the fundus, an optical system driving means for driving the photographing optical system in a three-dimensional direction, and the alignment detecting means. When detecting rough alignment of the photographing optical system with respect to the fundus, auto-alignment control means for controlling the drive of the optical system driving means to perform automatic control of alignment of the photographing optical system with respect to the fundus, ,
The focusing start position correcting unit is set to correct the focusing start position by controlling the operation of the lens driving unit based on the eye refractive power data during the alignment control operation by the auto alignment control unit. With this configuration, the focusing operation can be performed in a shorter time than after the alignment.

Further, in the invention according to claim 3, the focusing start position correcting means controls the operation of the lens driving means when there is no eye refractive power data, so that the focusing lens is adjusted to the eye for emmetropy when the alignment is completed. Since the configuration is set to be located at the position of, when there is no eye refractive power data, the position of the emmetropic eye as the initial position,

[Brief description of the drawings]

FIG. 1 is an optical layout diagram showing a 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 reaching point when the cornea to be examined is shifted from an appropriate position in the X, Y, and Z axis directions. B
FIG. 4 is an explanatory diagram showing a light flux reaching point when the cornea to be examined is shifted from an appropriate position in the Z-axis direction. C is an explanatory diagram showing a light flux reaching point when the cornea to be examined is at an appropriate position.

FIG. 4A is a perspective view showing a slit index plate. b
FIG. 4 is an explanatory view showing a direction of declination.

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 a focused 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.

FIG. 10 is a side view of a fundus camera including the optical system shown in FIG.

FIG. 11 is an explanatory view showing another embodiment of the present invention.

[Explanation of symbols]

200: photographing optical system 224: TV camera 224a: area CCD (imaging means) 208: focusing lens 400: alignment optical system 500: focus detection optical system 602: Focus detection circuit 604 ... Alignment detection circuit (alignment detection means) 605 ... Controller (focus control means, focus start position correction means, auto alignment control means) PM1 to PM3 ... Pulse motor (optical Driving device (lens driving means) E: Eye to be examined Er: Er

Claims (3)

[Claims] 1. A fundus camera comprising: a photographing optical system provided with a focusing lens that focuses an imaging unit on a fundus of an eye to be inspected; and a lens driving unit that drives and controls the focusing lens in an optical axis direction. Data input means for inputting eye refractive power data of the eye to be examined, and a focus start position correction means for controlling the operation of the lens driving means based on the eye refractive power data to correct a focus start position A fundus camera comprising: 2. An alignment detecting means for detecting an alignment of the photographing optical system with respect to the fundus, an optical system driving means for driving the photographing optical system in a three-dimensional direction,
An auto alignment control unit for controlling the drive of the optical system driving unit to perform automatic control of the alignment of the imaging optical system with respect to the fundus when the alignment detecting unit detects coarse alignment of the imaging optical system with respect to the fundus; The focusing start position correcting unit corrects the focusing start position by controlling the operation of the lens driving unit based on the eye refractive power data during the alignment control operation by the auto alignment control unit. The fundus camera according to claim 1, wherein the setting is made to perform the following. 3. The in-focus start position correcting means controls the operation of the lens driving means when there is no eye refractive power data so that the in-focus lens is positioned at the emmetropic eye when the alignment is completed. The fundus camera according to claim 1, wherein the camera is set.