JP2006110113A - Ophthalmic imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the need of branch light path for focus index projection, to miniaturize the system and to reduce the number of parts. <P>SOLUTION: A focus unit 11 comprises a prism level 11a, a polarizing prism 11b, 11c, slit chart 11e having slit opening 11d. The polarizing prism 11b, 11c are arranged so that the polar direction is reverse. The slit opening 11d extends over the polarizing prism 11b, 11c in approximately half, the slit opening 11d is non-translucent part, and the light entering polarizing prism 11b, 11c, only passed this slit opening 11d. The light generated from a focus index illumination light source illuminates the slit opening 11d through the polarizing prism 11b, 11c. The image of slit opening 11d illuminated forms the two slit images on the eyeground by polarizing prism 11b, 11c. Focus adjustment is made by making this slit image S1, S2 arranged in a straight line. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ophthalmologic photographing apparatus used in an ophthalmic clinic or the like.

  Conventionally, in a fundus camera, a focus index projection composed of an index for focus detection, a light source for illuminating the index, and a projection optical system having a deflection prism for projecting an index image from a different position of the pupil onto the fundus of the eye to be examined A lens barrel and a micromirror that branches the optical path from the fundus illumination optical system, and a mechanism that moves the micromirror and the focus index projection lens barrel in the optical axis direction in conjunction with the focus adjustment of the imaging optical system. Patent Documents 1 to 3 disclose a method in which a mechanism for retracting a micromirror to the outside of the optical path is provided, and the fundus is focused while viewing an index image projected onto the fundus.

Japanese Patent Laid-Open No. 5-95902 JP-A-8-33610 JP-A-8-150121

  Patent Documents 4 and 5 disclose a method in which a minute prism is provided in the illumination optical system, a slit image illuminated with fundus observation light is projected onto the fundus, and focus adjustment is performed.

JP-A-6-142050 JP 54-54494 A

  In the above conventional method, since the entire focus index projection barrel provided by branching from the fundus illuminating optical system has to be moved in the optical axis direction, a large space must be ensured and it is difficult to miniaturize the apparatus. In addition, the number of parts is large and adjustment takes time, which is expensive. There is a problem that the assembly work such as the angle adjustment of the micromirror and the alignment of the index image and the micromirror is complicated, and the wires are connected. In order to move the light source, there is a problem that the electric wire which does not move is rubbed.

  Furthermore, the method of providing a micro prism in the illumination optical system projects the focus index by decentering the fundus illumination light with the prism, so that the focus index portion is darker than the surrounding fundus region, and focus adjustment is difficult, or Since fundus illumination and focus index illumination are performed with a single light source, there is a problem in that the amount of light cannot be adjusted independently, and usability is poor.

  An object of the present invention is to provide an ophthalmologic photographing apparatus that solves the above-described problems, has a small number of parts, and can perform focusing by an easy operation.

  The technical features of the ophthalmologic photographing apparatus according to the present invention for achieving the above object include a fundus imaging optical system having a focus adjusting means, and a perforated mirror that branches an optical path between the fundus imaging optical system and the illumination optical system. In the illumination optical system, the first relay lens and the second relay lens having a focal point in the vicinity of the aperture of the perforated mirror are disposed between the first and second relay lenses. A focus unit that has a slit index for fundus projection and a deflecting prism disposed around the slit index, and that is movable in the optical axis direction in conjunction with the focus adjusting means; and a substantially focal position of the second relay lens And a lighting unit for illuminating the slit index.

  According to the ophthalmologic photographing apparatus according to the present invention, since the focus index projection unit is arranged in the fundus illumination optical system, the slit index with a high contrast is projected with a small number of parts without branching the optical path. Therefore, the apparatus can be reduced in size and price without impairing operability. Further, since the light source position is fixed, the structure can be simplified and the reliability of the light source can be improved.

  The present invention will be described in detail based on the embodiments shown in the drawings.

  FIG. 1 is a configuration diagram of the fundus camera of the embodiment. In front of the eye E, the objective lens 1, the perforated mirror 2, the photographing aperture 3, the focusing lens 4, the photographing lens 5, the color separation prism 6, the image sensors 7r and 7g, arranged in the hole of the perforated mirror 2, An imaging mechanism consisting of 7b is arranged to constitute a fundus observation imaging means.

  The fundus illumination system positioned in the incident direction of the perforated mirror 2 is reflected from the perforated mirror 2 side by the cornea stop 8 having a ring-shaped opening projected to the vicinity of the cornea, the first relay lens 9 and the objective lens 1. A focus unit 11 having a black spot plate 10 with a black spot to be removed formed in the vicinity of the optical axis, a prism, and a focus index, moving in the optical axis direction in conjunction with the focus lens 4, and retracting out of the optical path when taking a still image. 2 having a relay lens 12, an optical path branching mirror 13 that reflects visible light and transmits infrared light, and a ring-shaped opening 14 a that projects near the rear surface of the lens to be examined, and has a small opening 14 b at the center. 3. A diaphragm 14 shown in FIG. 3 having a ring-shaped opening 15a projected near the pupil Ep of the eye E, or an LED emitting infrared light arranged circumferentially as shown in FIG. Focus index illumination light source 17 arranged in a plurality of viewing illuminant 16a~16f a central portion made are arranged.

  In the reflection direction of the optical path branching mirror 13, a lens diaphragm 18 having a ring-shaped opening that projects near the rear surface of the lens to be examined, a ring diaphragm 19 having a ring-shaped opening that projects near the pupil of the eye E, and an imaging light source 20 are arranged. Has been.

  The photographing aperture 3 in the aperture of the perforated mirror 2 is substantially at the focal position of the first relay lens 9, and the aperture 15 and the aperture 19 are disposed at the approximate focal position of the second relay lens 12. Further, the ring-shaped opening 15 a of the ring diaphragm 15 is illuminated by the illumination light sources 16 a to 16 f, and the small opening 15 b is illuminated by the index illumination light source 17.

  As shown in the sectional view of FIG. 5, the focus unit 11 includes a prism base 11a, deflection prisms 11b and 11c, and a slit chart 11e having a slit opening 11d. As shown in FIG. 6, the deflection prisms 11b and 11c are prisms. It arrange | positions so that the deflection | deviation direction may become reverse direction in the center part of the base 11a. As shown in FIG. 7, the slit chart 11e is arranged at the center of the prism base 11a, and the slit opening 11d extends over the deflecting prisms 11b and 11c substantially equally. The portions other than the slit opening 11d of the slit chart 11e are non-light-transmitting portions, and the light incident on the prism portion passes only through the slit opening 11d.

  The outputs of the image sensors 7r, 7g, and 7b are connected to the image board 22 via the amplifier circuits 21r, 21g, and 21b. The image board 22 includes an A / D converter 23 and a memory 24. The output is connected to the image control means 25, the television monitor 27, and the system bus 26. Connected to the system bus 26 are a CPU 28, a photographing switch 29, a recording unit 30, a focus switch 31, an observation light amount adjustment knob 32, a focus index brightness adjustment switch 33, and a driving circuit 34 for the photographing light source 20.

  In order to photograph the fundus of the subject using this fundus camera, the photographer seats the subject in front of the fundus camera, observes the fundus Er of the eye E, and observes the eye E and the fundus camera. Alignment and focus alignment are performed.

  In focusing, infrared light emitted from the observation light sources 16a to 16f passes through the ring-shaped opening 15a of the ring diaphragm 15 and the ring-shaped opening 14a of the crystalline lens diaphragm 14, passes through the optical path branching mirror 13, and the second relay lens. 12, the focus unit 11, the black spot plate 10, the first relay lens 9, and the aperture of the corneal diaphragm 8, reflected to the left by the perforated mirror 2, passed through the objective lens 1 and through the pupil Ep of the eye E to be examined. Illuminates the fundus Er. The thus illuminated image of the fundus Er passes through the objective lens 1, the photographing aperture 3, the focus lens 4, and the photographing lens 5 again and is guided by the color separation prism 7 to the image sensor 7 r that receives red and infrared light. .

  The signal from the image sensor 7 r is converted into a video signal by the amplifier circuit 21 r, input to the image board 22, and further displayed on the television monitor 27 via the image control means 25. The photographer observes the fundus image reflected on the television monitor 27 and confirms the imaged region. When the brightness of the fundus image is not appropriate, the photographer operates the observation light amount adjustment knob 32. In accordance with the operation of the knob 32, the amount of current flowing through the observation light sources 16a to 16f is adjusted and the light emission intensity changes, so that the photographer can observe the fundus image with appropriate brightness.

  The light emitted from the focus index illumination light source 17 passes through the small aperture 15 b of the ring aperture 15 and the small aperture 14 b of the crystalline lens aperture 14, passes through the optical path branch mirror 13, passes through the second relay lens 12, and the focus unit 11. The slit opening 15d is illuminated through the deflection prisms 11b and 11c. The image of the slit aperture 11d thus illuminated passes through the apertures of the black spot plate 10, the first relay lens 9, and the corneal stop 8 by the action of the deflecting prisms 11b and 11c, and is a mirror around the perforated mirror 2. The light is reflected leftward by the unit and projected onto the fundus Er of the eye E through the objective lens 1.

  Since the small aperture 15b of the ring diaphragm 15 and the perforated mirror 2 are substantially conjugate with the pupil Ep, all the light emitted from the small aperture 15b without the action of the deflecting prisms 11b and 11c is from the perforated mirror 2. Since it enters the hole, it is not reflected by the surrounding mirror. However, due to the presence of the deflection prisms 11b and 11c, the image of the small aperture 15b is formed as two slit images at a position deviated from the optical axis, that is, the hole position of the perforated mirror 2.

  In addition, since the right half and the left half of the slit image are deflected in different directions, the image of the small aperture 15b is formed at two symmetrical positions sandwiching the hole of the perforated mirror 2. As a result, the left and right slit images are projected onto the fundus Er from two vertically symmetrical positions across the optical axis on the pupil Ep as shown in FIG.

  Accordingly, as shown in FIGS. 9A and 9B, when the projection positions of the slit images S1 and S2 are deviated from the fundus Er, the left and right slit images S1 and S2 are projected apart from each other. In addition, as shown in FIG. 9C, when the eye fundus Er coincides, the slit images S1 and S2 are aligned.

  As described above, since the small opening 15b is disposed at the focal position of the second relay lens 12, the light emitted from the second relay lens 12 is substantially parallel light. Therefore, even when the focus unit 11 moves on the optical axis, the deflection angle is always constant, and the amount of eccentricity on the pupil Ep is always constant, so that the focus accuracy is not impaired.

  The slit images S1 and S2 projected on the fundus Er pass through the pupil Ep, the objective lens 1, the photographing aperture 3, and the focus lens 5 again, enter the color separation prism 7, and are guided to the image sensor 7r. This signal is converted into a video signal by the amplifier circuit 21r, input to the image board 22, displayed on the television monitor 27 together with the fundus image, and the photographer operates the focus switch 31 so that the two slit images are aligned. By doing so, focus adjustment can be performed.

  At this time, if the brightness of the focus index image is not appropriate, the brightness adjustment switch 33 of the slit images S1 and S2 is operated. Thereby, the current flowing through the index illumination light source 17 is adjusted, and the brightness of the slit images S1 and S2 can be adjusted by changing the emission energy. As described above, since the observation light sources 16a to 16f and the focus index illumination light source 17 are separately provided, the brightness of the focus index can be appropriately adjusted while maintaining the brightness of the fundus image appropriately. A contrast index image can be observed.

  As described above, since the ring stop 15 and the perforated mirror 2 are substantially conjugate, the small opening 15 b opened on the optical axis of the ring stop 15 forms an image at the opening of the perforated mirror 2. That is, of the light emitted from the indicator illumination light source 17 and passing through the opening 15b, light other than the light deflected through the deflecting prisms 11b and 11c enters the aperture of the perforated mirror 2 and is reflected in the direction of the objective lens 1. There is no ghost light.

  As described above, when the photographer operates the focus switch 31 so that the slit images S1 and S2 are in a straight line, the focus lens 4 and the focus unit 11 move in the optical axis direction, as shown in FIG. 9C. As described above, the slit images S1 and S2 are conjugately projected onto the fundus Er. Since the focus lens 4 is adjusted so that the imaging elements 7b, 7g, and 7r are always kept conjugate with the focus index projection plane, if the left and right slit images S1 and S2 are taken in a straight line, a focused image is obtained. can get.

  When the photographer operates the photographing switch 29 after the preparation for photographing is completed in this way, the CPU 28 detecting this input turns off the observation light sources 16a to 16f and the indicator illumination light source 17, and retracts the focus unit 11 out of the optical path. Then, the amplification circuits 21r, 21g, and 21b are set to an amplification factor for taking a still image, the accumulation of the image sensors 7b, 7g, and 7r is started, and the photographing light source 20 emits light.

  The light emitted from the imaging light source 20 passes through the aperture of the ring diaphragm 19 and the aperture of the crystalline lens diaphragm 18 and is reflected upward by the optical path branching mirror 13, and the second relay lens 12, the black spot plate 10, and the first relay lens. 9. It passes through the opening portion of the corneal diaphragm 8 and is reflected leftward by the mirror portion of the perforated mirror 2 to illuminate the fundus Er via the objective lens 1 and the pupil Ep.

  The fundus image illuminated in this way again passes through the pupil Ep, the objective lens 1, the photographing aperture 3, the focus lens 4, and the photographing lens 5, and is blue (B), green (G), and red (R) by the spectral prism 6. Are imaged on the image sensors 7b, 7g, and 7r, converted into electrical signals, converted into digital data by the A / D converter 23 of the image board 22, and displayed on the television monitor 27. At the same time, it is recorded on the recording medium D by the recording means 30. Then, the focus unit 11 is again arranged in the optical path, the observation light sources 16a to 16f and the index illumination light source 17 are turned on, and a series of photographing operations is completed.

It is a block diagram of the fundus camera of the first embodiment. It is a front view of a crystalline lens aperture. It is a front view of a ring aperture. It is explanatory drawing of arrangement | positioning of an observation light source and a focus parameter | index illumination light source. It is sectional drawing of a focus unit. It is a top view of a focus unit. It is a rear view of a focus unit. It is explanatory drawing of the incident position of the optical slit image on a pupil. It is explanatory drawing of a mode that a slit image isolate | separates.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Objective lens 2 Perforated mirror 4 Focus lens 5 Shooting lens 6 Color splitting prism 7 Imaging element 9 1st relay lens 11 Focus unit 12 2nd relay lens 13 Optical path branching mirror 14, 15, 18, 19 Aperture 16 Observation light source 17 Focus indicator illumination light source 21 Amplifying circuit 25 Image control means 27 TV monitor 28 CPU
29 Shooting switch 30 Recording means

Claims (6)

  A fundus imaging optical system having a focus adjusting unit; and a perforated mirror that branches an optical path between the fundus imaging optical system and the illumination optical system, and the illumination optical system has a focal point near the aperture of the perforated mirror. A first relay lens and a second relay lens, and a slit index for fundus projection and a deflecting prism disposed around the slit index, disposed between the first and second relay lenses. In addition, a focus unit movable in the optical axis direction in conjunction with the focus adjustment means, a light shielding member disposed at a substantially focal position of the second relay lens, and an illumination means for illuminating the slit index are provided. An ophthalmologic photographing apparatus characterized by.   The ophthalmologic photographing apparatus according to claim 1, wherein the illumination unit is disposed in an opening provided in the vicinity of the optical axis of the light shielding member.   The ophthalmologic photographing apparatus according to claim 1, wherein the slit index projects two slit index images on the fundus by the deflecting prism.   4. The ophthalmologic photographing apparatus according to claim 3, wherein the two slit index images are obtained by dividing one slit opening by the two deflection prisms.   The ophthalmologic photographing apparatus according to claim 1, wherein the illumination unit is an LED.   The ophthalmologic photographing apparatus according to claim 5, wherein an LED for fundus illumination is arranged around the LED.

Images