JPH09289973A - Fundus camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a focus even at the time of fluorescent eye ground photographing by a simple structure without a movable part. SOLUTION: A luminous flux from an LED light source 14 is passed through an opening plate 13 and a lens 12, reflected on the reflection surface 9a of a prism 9, advanced in an optical path 01 and projected from a part of a pupil P to an eye ground Er as an index luminous flux. The reflected light is advanced on the optical paths 03 and 04, passed through a fluorescent filter and a focus lens 18, etc., reflected in the direction of the optical path 06 on the reflection surface 27a of the prism 27, bisected in a separation prism 31, passed through the lens 32 and a columnar lens 33 and received by a CCD line sensor 34 as a focusing luminous flux image. Since the position of the focusing luminous flux image is shifted from a prescribed position by the diopter of an eye E to be tested, the position is recognized by a signal processing arithmetic means 35, the focus lens 18 is moved by a driving means 17 so as to bring it to the prescribed position and automatic focusing is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera having a focus detecting means for detecting a focused light beam.

[0002]

2. Description of the Related Art Conventionally, in a fundus camera that performs fluorescence photography, a light splitting member is arranged between relay lenses of an illumination optical system, and a light flux from a focusing light source is projected on the fundus of an eye to be examined through the light splitting member. Then, the reflected light from the fundus is split by a light splitting member arranged behind the photographing optical system, and the photoelectric sensor receives the light to detect the in-focus state. Then, the plurality of filters are freely inserted into and removed from the optical path of the photographing optical system by the driving means, and fluorescent fundus photographing is performed.

[0003]

However, the above-mentioned conventional fluorescence photographing fundus camera has the following problems.

(1) It is difficult to obtain a fluorescent fundus image with good contrast depending on the spectral sensitivity of the photographic medium.

(2) A light splitting member that guides a focused light beam is provided in the shooting illumination optical path, which affects shooting.

(3) The light splitting member may become conjugate with the fundus depending on the diopter of the subject's eye, and the reflection boundary surface of the light splitting member appears in the image, making it difficult to see the fundus image.

(4) The appearance of the split optotype when focusing is different depending on the photographing mode.

(5) A light transmission correction plate is necessary to correct the shift of the in-focus position that occurs when the fluorescence filter is inserted into or removed from the optical path.

(6) A plurality of driving means for inserting and removing a plurality of lenses and filters at different positions of the optical path is required.

(7) A dedicated focus display member including an LED or the like is required near the finder.

(8) Since the focus detection result is used only for focus display and focus drive, the distance between the fundus image and the fundus of the eye cannot be known.

(9) Since the fluorescent filter is formed of an optical thin film, a photographed image having sensitivity to infrared light affects a photographed image.

The first object of the present invention is to solve the above-mentioned problem (1).
And to provide a fundus camera capable of obtaining a fluorescent fundus image with good contrast regardless of the spectral sensitivity of the recording medium.

A second object of the present invention is to provide a fundus camera in which the above-mentioned item (2) is solved and a light splitting member for guiding a focused light beam does not affect photographing.

The third object of the present invention is to solve the above-mentioned problem (3).
It is an object of the present invention to provide a fundus camera in which the boundary surface is not reflected even when a thin prism having a reflecting surface at the center is used as a light splitting member.

The fourth object of the present invention is to solve the above-mentioned problem (4).
SUMMARY OF THE INVENTION It is an object of the present invention to provide a fundus camera that automatically corrects a focus movement caused by mode conversion.

The fifth object of the present invention is to solve the above-mentioned problem (5).
The object of the present invention is to provide a fundus camera capable of correcting the in-focus movement caused by inserting and removing the filter without using a correction plate.

The sixth object of the present invention is to solve the above-mentioned problem (6).
It is an object of the present invention to provide a fundus camera in which the following lens can be arranged at a position close to the diaphragm by saving the space near the diaphragm.

The seventh object of the present invention is to solve the above-mentioned problem (7).
SUMMARY OF THE INVENTION It is an object of the present invention to provide a fundus camera capable of performing focused display with a simple structure.

The eighth object of the present invention is to solve the above-mentioned problem (8).
The object of the present invention is to provide a fundus camera that can obtain the information of high diagnostic value by knowing the distance from the fundus of the fundus image.

The ninth object of the present invention is to solve the above-mentioned problem (9).
It is an object of the present invention to provide a fundus camera in which an image is not affected even by a photographic medium having sensitivity to infrared light.

[0022]

A fundus camera according to a first aspect of the invention for achieving the above object is an illumination optical system for irradiating a fundus of an eye to be examined, wherein a fluorescence excitation filter is detachably provided in an optical path. An observation / photographing optical system for observing and photographing a fundus image by providing a filtration filter so as to be freely inserted into and removed from the optical path, and a fundus via a first light splitting member provided on the eye to be examined side of the illumination optical system relative to the fluorescence excitation filter. A projection optical system for projecting a focused light flux having a wavelength longer than the fluorescence wavelength, and a focus detection means for detecting the focused light flux via a second light splitting member provided behind the fluorescent filter. And the fluorescence excitation filter has a characteristic of not transmitting a light flux of the fluorescence wavelength.

In the fundus camera according to the second aspect of the present invention, a fluorescence excitation filter is removably provided in the optical path to illuminate the fundus of the eye to be inspected, and a fluorescence filtering filter is removably provided in the optical path to provide a fundus image. A projection for projecting a focused light flux having a wavelength different from the fluorescence wavelength onto the fundus through an observation and photographing optical system for observing and photographing the eye and a first light splitting member provided on the light source side of the illumination optical system rather than the pupil conjugate side. An optical system and a focus detection unit that detects the focused light flux via a second light splitting member provided in the observation and photographing optical system, and the fluorescence excitation filter transmits the focused light flux. It is characterized by having.

In the fundus camera according to the third aspect of the present invention, a fluorescence excitation filter is removably provided in the optical path to illuminate the fundus of the eye to be inspected, and a fluorescence filter is provided in the optical path so that the fundus image is removable. An observation and photographing optical system for observing and photographing, and a focus detection means for detecting a focused light flux through a light dividing member provided in the illumination optical system or the observation and photographing optical system. It is characterized in that it is not conjugated to the fundus of the eye to be examined regardless of the diopter of the eye.

A fundus camera according to a fourth aspect of the present invention is a fundus camera having a plurality of photographing modes, which has a focus detection means and automatically corrects the focus state when the photographing mode is changed. And

A fundus camera according to a fifth aspect of the invention is a fundus camera in which a filter is freely inserted into and removed from a photographing optical system, which has a focus detection means, and corrects the focus when the filter is inserted or removed. Is characterized by.

A fundus camera according to a sixth aspect of the invention is a fundus camera in which a plurality of filters are removably provided in a photographing optical system, wherein the plurality of filters are inserted into and removed from the photographing optical system by rotation of a rotating member. Characterize.

A fundus camera according to a seventh aspect of the invention is a fundus camera in which a filter and a diopter correction lens are removably provided in a taking optical system, wherein the filter and the diopter correction lens are rotated by a rotating member to take the taking optical system. It is characterized by being inserted into and removed from the system.

A fundus camera according to an eighth aspect of the present invention is a fundus camera having a detection means for detecting a focused light beam, and has a display means for displaying a fundus image, and the detection result of the detection means is displayed on the display means together with the fundus image. Characterized by displaying or recording.

A fundus camera according to a ninth aspect of the invention is a fundus camera having a detecting means for detecting a focused light beam, and calculates a distance in the optical axis direction based on a detection result of the detecting means to display the fundus image together with the fundus image. It is characterized by recording.

A fundus camera according to the tenth aspect of the invention is characterized by including a fluorescence filter including a multilayer optical thin film layer and an absorption filter.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 is a configuration diagram of a fluorescence photography fundus camera of the first embodiment, in which an optical path from a continuous light emitting light source 1 such as an incandescent lamp conjugate with a pupil P of an eye E to an objective lens 2.
On O1, a filter 3, a relay lens 4, a photographing strobe light source 5, a ring slit 6 conjugate with the pupil P, a visible fluorescence excitation filter 7 or an infrared fluorescence excitation filter 8 which is alternatively inserted into the optical path O1, Regardless of the diopter of the eye E, the prism 9 and the relay lens 1 which are non-conjugated light-dividing members to the fundus Er.
0, a perforated mirror 11 that is substantially conjugate to the pupil P is sequentially arranged.

On the optical path O2 in the incident direction of the reflecting surface 9a formed in the central part of the prism 9, the lens 12, the aperture plate 13 having a rectangular aperture conjugate with the stereoscopic eye fundus Er, and longer than the infrared fluorescent light. LE that emits a focused light beam of a wavelength and is conjugate with the pupil P
D light sources 14 are arranged. It should be noted that the filter 3 does not transmit a light flux having the same wavelength as that of the LED light source 14 out of the light flux emitted from the continuous light emission light source 1 in order to increase the S / N ratio at the time of focus detection.

On the optical path O3 behind the perforated mirror 11,
A diaphragm 15, a turret 16 and a driving means 1 which are conjugate with the pupil P.
Focus lens 18 having 7 and imaging and photographing lens 1
9, a switching mirror 20, and a film camera 21 including a film 21a are sequentially arranged. Turret 1
As shown in FIG. 2, a visible fluorescence filtering filter 22, an infrared fluorescence filtering filter 23, a diopter conversion lens 24, and an opening 25 at the time of color photographing are attached to the turret 6.
A stepping motor (not shown) is connected to the central axis 16a of the rotary shaft 6, and the visible fluorescent filter 22 and the infrared fluorescent filter 2 are rotated by rotating the turret 16.
3. Any one of the diopter conversion lens 24 and the aperture 25 is selected and inserted into the optical path O3.

When observing visible light, a movable mirror 26 that transmits infrared light and reflects visible light on the optical path O4 in the reflection direction of the switching mirror 20 located at the position shown in FIG. Regardless of the prism 27 and the lens 2 which are not conjugated with the fundus Er
8. Imaging means 29 such as a television camera and an electronic camera are sequentially arranged. In addition, the visible fluorescence image is captured by the image pickup means 2.
The movable mirror 26 is designed to be retracted from the optical path O4 when the image is recorded and recorded at 9, but the visible fluorescent light is emitted from the film 2.
Movable mirror 26 if used only for shooting with 1a
Instead of a fixed mirror.

On the optical path O5 in the reflection direction of the movable mirror 26 at the position shown in FIG. 1, an eyepiece lens 30 which the examiner's eye e sees is arranged, and a reflecting surface 27a formed at the center of the prism 27. On the optical path O6 in the reflection direction, the separation prism 31, which is conjugate with the pupil P, the lens 32, the cylindrical lens 33, and the CCD line sensor 34, which is conjugate with the emmetropic fundus Er, are sequentially arranged. Then, the driving means 17, the imaging means 29, C
The output of the CD line sensor 34 is connected to the signal processing calculation means 35, and the output of the signal processing calculation means 35 is the storage means 3.
6. Connected to the television monitor 37.

FIG. 3 shows the spectral reflection characteristics P1 and P2 of the reflecting surface 9a of the prism 9 and the reflecting surface 27a of the prism 27. The reflecting surface 9a reflects the wavelength light of the LED light source 14 and transmits the excitation light. The reflecting surface 27a reflects the wavelength light of the LED light source 14 and almost transmits the infrared fluorescent light.

FIG. 4 shows the spectral emission characteristics L of the LED light source 14, the infrared fluorescence excitation filter 8 and the infrared fluorescence filtration filter 17.
3 shows the spectral transmission characteristics E2 and B2. The infrared fluorescent filter 17 is composed of a multilayer optical thin film layer that determines wavelength characteristics around 800 nm and an absorption filter that absorbs visible light, and transmits infrared fluorescent wavelength light and the wavelength light of the LED light source 14. Further, the infrared fluorescence excitation filter 8 transmits the excitation wavelength light and blocks the infrared fluorescence wavelength light and the wavelength light of the LED light source 14.

FIG. 5 shows the spectral transmission characteristics E1 and B1 of the visible fluorescence excitation filter 7 and the visible fluorescence filtration filter 16, respectively. The visible fluorescence excitation filter 7 is a multilayer optical thin film layer surface that determines the characteristics around 500 nm and the LED light source 14. And an absorption filter that absorbs the near-infrared wavelength light, and transmits the excitation wavelength light and blocks the visible fluorescence wavelength light and the wavelength light of the LED light source 14. The visible fluorescence filter 16 blocks the excitation wavelength light and transmits the visible fluorescence wavelength light and the wavelength light of the LED light source 14.

The luminous flux from the continuous emission light source 1 is a filter 3, a relay lens 4, a photographing strobe light source 5, a ring slit 6, a visible fluorescence excitation filter 7, a prism 9, a relay lens 10, a perforated mirror 11, and an objective lens 2. The fundus Er of the eye E to be examined is illuminated via. The reflected light from the fundus Er passes through the objective lens 2, the perforated mirror 11, the diaphragm 15, the visible fluorescence filtering filter 16, the focus lens 18, the imaging and photographing lens 19, the switching mirror 20, the movable mirror 26, and the eyepiece lens 30 for inspection. It reaches the human eye e.

When observing or photographing with the image pickup means 29,
The movable mirror 26 is retracted from the optical path O4, and the light flux from the continuous light emitting light source 1 or the strobe light source 5 is reflected by the fundus Er to be reflected on the optical path.
A lens 28 passes through O3 and O4 to form a fundus image on the image pickup means 29. Further, when the film 21a of the film camera 21 is photographed, the switching light source 20 is jumped up and retracted from the optical path O3 at the same time when the strobe light source 5 is emitted, and the fundus image is photographed on the film 21a.

The luminous flux from the LED light source 14 is transmitted through the aperture plate 1.
3, the light passes through the lens 12, is reflected by the reflecting surface 9a of the prism 9, travels along the optical path O1, and is projected from a part of the pupil P on the fundus Er as an index light beam. The reflected light travels on the optical paths O3 and O4,
It passes through the movable mirror 26, is reflected by the reflecting surface 27a of the prism 27 in the optical path O6 direction, and is split into two by the separating prism 31.
The light passes through the lens 32 and the cylindrical lens 33 and is received by the CCD line sensor 34.

FIG. 6 is a sectional view of the light flux at the pupil P, and an image 6'is an image of the ring slit 6 and represents the light flux of the continuous light emitting light source 1 or the strobe light source 5. Also, statue 15 '
The image of the diaphragm 15 represents the photographing light flux, and the image 14 'represents the image of the LED light source 14 and the focused light flux projected from the lower portion of the pupil P. Further, FIG. 7 shows the aperture plate 13 projected on the fundus Er.
8 is an image 13 'of a vertically long rectangular shape, and FIG. 8 shows a focused light flux image 13' which is split into two by the separation prism 31 and received by two CCD line sensors 34 on the same substrate as the cylindrical lens 33. ing.

The position of the focused light flux image 13 'is deviated from the predetermined position on the CCD line sensor 34 according to the diopter of the eye E to be inspected. Therefore, the position is recognized by the signal processing calculation means 35,
The driving means 1 is arranged so that the focused light flux image 13 'is at a predetermined position.
The focus lens 18 is moved via the control unit 7. Then, the image of the image pickup means 29 is displayed on the television monitor 37 and stored in the storage means 36.

When performing infrared fluorescence photography, the infrared fluorescence excitation filter 8 and the infrared fluorescence filtration filter 23 are inserted into the optical paths O1 and O3 instead of the visible fluorescence excitation filter 7 and the visible fluorescence filtration filter 22, respectively. To be done.

In this way, since the focus detection can be performed during the fluorescent photographing of both visible light and infrared light, the focused luminous flux does not affect the photographing observation and cause any trouble. Further, since the prisms 9 and 27 are not conjugated to the fundus Er, the boundaries between the reflecting surfaces 9a and 27a are not projected, and the prisms 9 and 27 can be made thin and a space-saving design is required. It will be possible. Further, by using the various filters as described above, it is possible to obtain necessary characteristics in a wide wavelength band from visible light to infrared light. Therefore, various photographing media including a television camera having infrared sensitivity. Is not used for fluorescent fundus photography, the contrast does not decrease.

Further, by using the turret 16, the filters 22 and 23, the diopter exchange lens 24 and the like can be inserted and removed at the same position on the optical path O3, and the focus lens 18 can be placed in the vicinity of the diaphragm 15 without taking a space. Since it can be moved up to, the diopter correction range can be widened.
When the turret 16 is rotated to change from the filters 22 and 23 to the opening 25, the optical path length is different and the focus is changed, but it can be corrected by moving the focus lens 18. In this way, even when the fluorescence photographing mode is changed to the color photographing mode, it is possible to detect the focusing deviation by the focusing detecting means such as the CCD line sensor 34 and automatically focus the image. There is no need. In the apparatus of FIG. 1, it is also possible to manually turn the focus knob to perform the focusing operation.

On the television monitor 37, the fundus position display value A calculated from the in-focus state detected by the in-focus detecting means such as the CCD line sensor 34 is displayed. The value A is an intraocular equivalent optical path direction distance (unit: mm) obtained by paraxial calculation assuming a standard eye, and zero indicates that the subject is in focus. Therefore, while focusing on the value A, it is possible to manually adjust the focus and quantitatively perform the front focus and the rear focus.

By storing the value A and the image in the storage means 36, the fundus image Er 'can be recorded together with the depth information, and the fundus image can be more accurately diagnosed. Furthermore, the fundus display means can also be used as the focus display means.

FIG. 9 is a block diagram of the fluorescence photographing fundus camera of the second embodiment, in which the driving means 17 and the signal processing calculating means 35 are shown.
Illustrations of the same members as those in the first embodiment are omitted.
On the optical path O7 from the focusing light source 40 conjugate to the pupil P to the objective lens 41, the near-infrared light of the aperture plate 42 having a rectangular opening conjugate with the emmetropic fundus Er, the lens 43, and the focusing light source 40 is provided. A dichroic mirror 44 that transmits and reflects visible light, a strobe light source 45 for photographing, a ring slit 46 that is conjugate to the pupil P, a fluorescence excitation filter 47 that can be inserted into and removed from the optical path O7, a relay lens 48, and a hole that is substantially conjugate to the pupil P. Mirrors 49 are sequentially arranged, and a relay lens 50 and a continuous emission light source 51 are arranged on an optical path O8 in the incident direction of the dichroic mirror 44.

On the optical path O9 behind the perforated mirror 49,
A diaphragm 52 that is conjugate with the pupil P, a fluorescent filter 53 that can be inserted into and removed from the optical path O9, a focus lens 54, a prism 55 that is a light splitting member that is non-conjugate with the fundus Er regardless of the diopter of the subject's eye E, and variable magnification. An image lens 56, a switching mirror 57 that reflects visible light, and a film camera 58 having a film 58a are sequentially arranged. On the optical path O10 in the reflection direction of the switching mirror 57, a mirror 59 and an eyepiece lens 60 which the examiner's eye e sees are arranged, and on the optical path O11 in the reflection direction of the reflection surface 55a formed of the multilayer optical thin film of the prism 55. Is a lens 61, a separation prism 62 conjugate with the pupil P, a lens 6
3, a cylindrical lens 64, and a CCD line sensor 65 that is conjugate with the emmetropic fundus Er are sequentially arranged.

FIG. 10 shows the spectral sensitivity characteristic S of the film 58a.
9 shows the spectral emission characteristic D of the focusing light source 40 and the spectral transmission characteristic L of the dichroic mirror 44. FIG. 11 shows the spectral transmission characteristics F1 and F2 of the fluorescence excitation filter 47 and the fluorescence filtration filter 53. The fluorescence excitation filter 47 transmits the excitation wavelength light and the wavelength light of the focusing light source 40 and blocks the fluorescence wavelength light. The fluorescence filter 53 transmits the fluorescence wavelength light and the wavelength light of the focusing light source 40 and blocks the excitation wavelength light. Further, FIG. 12 shows the spectral reflection characteristic R of the reflecting surface 55a.

The light beam from the focusing light source 40 is transmitted through the aperture plate 4.
2, a lens 43, a dichroic mirror 44, an imaging strobe light source 45, an image is once formed on a ring slit 46, a fluorescence excitation filter 47, a relay lens 48,
It is reflected by the perforated mirror 49, passes through the objective lens 41, passes through the lower portion 40 ′ of the pupil P as shown in FIG. 6, and is projected onto the fundus Er as a rectangular light beam 42 ′ as shown in FIG.

The reflected light passes through the objective lens 41, the hole portion of the perforated mirror 49, the diaphragm 52, the fluorescence filter 53, and the focus lens 54, and the reflection surface 55 of the prism 55.
reflected by a, transmitted through the lens 61, and separated by the prism 62
Is divided into two parts, and through the lens 63 and the cylindrical lens 64,
The line CCD sensor 65 receives the two light flux images 42 'as shown in FIG. The positions of the two light flux images 42 'are calculated and recognized by the signal processing calculation means 35, the display value A of FIG. 1 is displayed, and the lens 54 is driven to perform automatic focusing. Since the prism 55 is arranged in front of the variable power imaging lens 56, even if the variable power imaging lens 56 moves, the separation prism 6
The light flux on 2 does not change and does not affect the focus detection optical system. In addition, as in the first embodiment, the reflecting surface 55a
Is not conjugate to the fundus Er, its boundary is not projected. In addition, the light splitting member 44 has a light source 4 rather than the ring slit 46.
Since it is arranged on the 0 side, the light splitting member 44 does not affect the photographing illumination.

Filters 47 and 53 are connected to optical paths O7 and O9, respectively.
The focusing light source 40 has a wavelength longer than the sensitivity of the film 58a, so that the photographing light is not affected by the reflecting surface 55a. The wavelength light of the focusing light source 40 out of the light flux of the continuous light emitting light source 51 is removed by the light splitting member 44, and the light flux from the continuous light emitting light source 51 does not affect the focus detection, and the focusing is performed with high accuracy. Detection can be performed.

[0056]

As described above, in the fundus camera according to the first aspect of the invention, the first and second light splitting members are arranged in the illumination optical system and the photographing optical system, respectively, and the focusing having a wavelength longer than the fluorescence wavelength is performed. By projecting the luminous flux onto the fundus and receiving the fluorescent luminous flux and the focused luminous flux via the fluorescent filter, a fluorescent fundus image with good contrast can be obtained regardless of the spectral characteristics of the recording medium.

With the fundus camera according to the second aspect of the present invention, a fluorescent fundus image with good contrast can be obtained regardless of the spectral characteristics of the recording medium, and the light splitting member of the illumination system does not affect photographing.

In the fundus camera according to the third aspect of the present invention, the light splitting member is provided at a position not conjugate with the fundus of the eye to be examined of the illumination optical system or the photographing optical system, so that the focused light is focused on the fundus through the light splitting member. Since the boundary of the light splitting member is not displayed regardless of the diopter of the eye to be inspected when the light is guided to perform photographing, a clear fundus image can be obtained.

Since the fundus camera according to the fourth aspect of the present invention automatically corrects the focus in accordance with the change of the shooting mode, it is not necessary to sequentially perform the focus correction for each shooting mode.

Since the fundus camera according to the fifth aspect of the invention automatically corrects the focus when the filter is inserted into or removed from the photographing optical system, the focus is corrected when the filter is inserted into or removed from the photographing optical system. No correction plate is required.

In the fundus camera according to the sixth aspect of the present invention, since the plurality of filters are inserted into and removed from the photographing optical system by rotating the rotating member, space is saved and the degree of freedom in optical design is increased.

In the fundus camera according to the seventh aspect of the invention, since the filter and the diopter correction lens are inserted into and removed from the photographing optical system by rotating the rotating member, space is saved and the degree of freedom in optical design is increased.

Since the fundus camera according to the eighth aspect of the invention is provided with the fundus image display means for displaying the focus detection result together with the fundus image, the focus display can be performed with a simple structure.

The fundus camera according to the ninth aspect of the invention displays or records the distance in the optical axis direction together with the fundus image based on the focus detection result, so that information of high diagnostic value can be obtained.

In the fundus camera according to the tenth aspect of the invention, the fluorescent filter is composed of a multilayer optical thin film layer and an absorption filter, so that various photographing media can be used.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a front view of a turret.

FIG. 3 is a graph showing a spectral reflection characteristic of a prism.

FIG. 4 is a graph showing a spectral emission characteristic of a light source and a spectral transmission characteristic of a filter.

FIG. 5 is a graph showing a spectral transmission characteristic of a filter.

FIG. 6 is an explanatory diagram of each light flux image on the pupil.

FIG. 7 is an explanatory diagram of a light flux image from an aperture plate.

FIG. 8 is an explanatory diagram of a focused light flux on a sensor.

FIG. 9 is a configuration diagram of a second embodiment.

FIG. 10 is a graph showing spectral emission characteristics of a light source.

FIG. 11 is a graph showing a spectral transmission characteristic of a filter.

FIG. 12 is a graph showing a spectral reflection characteristic of a prism.

[Explanation of symbols]

 1, 51 Continuous emission light source 5, 45 Strobe light source 7, 8, 47 Fluorescence excitation filter 9, 27, 55 Prism 13, 42 Aperture plate 14, 40 Focusing light source 16 Turret 21, 58 Film camera 22, 23, 53 Fluorescence Filtration filter 29 Image pickup means 31, 62 Separation prisms 34, 65 CCD line sensor 35 Signal processing calculation means 36 Storage means 37 Television monitor

Claims (11)

[Claims] 1. An illumination optical system for irradiating a fundus of an eye to be examined with a fluorescence excitation filter removably provided in an optical path, and an observation and photography optics for observing and photographing a fundus image with a fluorescence filtration filter removably provided in the optical path. A projection optical system for projecting a focused light flux having a wavelength longer than the fluorescence wavelength on the fundus through a first light splitting member provided on the eye to be examined side of the fluorescence excitation filter in the illumination optical system, Focus detection means for detecting the focused light flux via a second light splitting member provided behind the fluorescence filter, and the fluorescence excitation filter has a characteristic of blocking the light flux of the fluorescence wavelength. A fundus camera characterized by the above. 2. The focused light flux is near infrared light.
The fundus camera described in. 3. An illumination optical system for irradiating a fundus of an eye to be examined with a fluorescence excitation filter removably provided in an optical path, and an observation and photography optics for observing and photographing a fundus image with a fluorescence filtration filter removably provided in the optical path. A projection optical system for projecting a focused light beam having a wavelength different from the fluorescence wavelength onto the fundus through a first light splitting member provided on the light source side of the illumination optical system rather than on the pupil conjugate side of the illumination optical system;
Focus detection means for detecting the focused light flux via a second light splitting member provided in the observation and photographing optical system, and the fluorescence excitation filter has a characteristic of transmitting the focused light flux. Characteristic fundus camera. 4. An illumination optical system for irradiating a fundus of an eye to be examined with a fluorescence excitation filter removably installed in the optical path, and an observation and photography optics for observing and photographing a fundus image with a fluorescence filtration filter removably installed in the optical path. System, and a focus detection means for detecting a focused light flux via a light splitting member provided in the illumination optical system or the observation and photographing optical system, the light splitting member regardless of the diopter of the eye to be examined. A fundus camera characterized by being non-conjugated to the fundus of the eye to be examined. 5. A fundus camera having a plurality of shooting modes, comprising a focus detection means, and automatically correcting the focus state according to the change of the shooting modes. 6. A fundus camera in which a filter is detachably attached to a photographing optical system, wherein the fundus camera has a focus detection means, and corrects the focus when the filter is inserted or removed. 7. A fundus camera in which a plurality of filters are removably provided in a photographing optical system, wherein the plurality of filters are inserted into and removed from the photographing optical system by rotation of a rotating member. 8. A fundus camera in which a filter and a diopter correction lens are removably provided in an image-taking optical system, wherein the filter and the diopter-correction lens are inserted into and removed from the image-taking optical system by rotation of a rotating member. Characteristic fundus camera. 9. A fundus camera provided with a detecting means for detecting a focused light beam, having a display means for displaying a fundus image, and displaying or recording the detection result of the detecting means together with the fundus image on the display means. Fundus camera. 10. A fundus camera provided with a detecting means for detecting a focused light beam, wherein the distance in the optical axis direction is calculated based on the detection result of the detecting means and displayed or recorded together with the fundus image. Fundus camera. 11. A fundus camera comprising a fluorescent filter including a multilayer optical thin film layer and an absorption filter.