JP6592249B2 - Fundus photographing device - Google Patents

Description

  The present invention relates to an ophthalmologic photographing apparatus, and more particularly to an ophthalmologic photographing apparatus such as a fundus camera capable of performing stereo or monocular photographing by switching between stereo photographing and monocular photographing with an electronic imaging unit.

  Conventionally, the fundus occupies a pair of left and right stereoscopic fundus images by dividing the reflected light from the fundus that is incident through the objective lens and forming the divided luminous flux with a pair of imaging optical systems. The camera is known.

  In Patent Document 1 below, a pair of left and right fundus images having parallax are temporarily formed as intermediate images from the divided light fluxes, and the pair of fundus images formed as the intermediate images are left and right by a pair of optical path dividing lenses. And a configuration for re-imaging on the imaging surface of the imaging means. With such a configuration, it is possible to effectively acquire two fundus images for stereoscopic viewing without using a prism for optical path division.

  Further, the ophthalmologic photographing apparatus disclosed in Patent Document 1 is configured not only to perform stereo photographing but also to perform monocular photographing (monaural photographing) by inserting a monocular photographing imaging lens in the optical path instead of the optical path splitting lens. ing.

Japanese Patent No. 5386512

  However, in the above-mentioned Patent Document 1, when the fundus is photographed by switching from stereo photography to monocular photography, there is a problem that ring-shaped flare enters the periphery of the fundus image and the image quality is deteriorated.

  Therefore, the present invention has been made to solve such problems, and provides a fundus imaging apparatus capable of performing stereo photography and monocular photography of the fundus by reducing the occurrence of ring-shaped flare around the fundus image. The issue is to provide.

The present invention
An ophthalmologic photographing apparatus capable of photographing a subject's eye fundus by switching between stereo photographing and monocular photographing with an electronic imaging means,
A two-hole aperture that is disposed at the anterior ocular segment conjugate position of the eye to be examined and divides the reflected light beam from the eye fundus of the eye into a pair of right and left light beams with parallax;
An imaging optical system that forms a pair of left and right fundus images as an intermediate image from the divided luminous flux;
A pair of optical path splitting lenses that separates the pair of fundus images formed as the intermediate image into left and right images and re-images them on the imaging surface of the electronic imaging means;
An imaging mask that defines an imaging range of the fundus disposed on the surface on which the intermediate image is formed;
A variable aperture stop having a variable aperture diameter disposed at a position different from the photographing mask and the two-hole aperture,
In conjunction with switching from stereo shooting to monocular shooting, the two-hole aperture is switched to a single-hole aperture, the pair of optical path splitting lenses is switched to a single imaging lens, and the aperture diameter of the variable aperture stop is changed. It is characterized by making it.

  In the present invention, a variable aperture stop having a variable aperture diameter is disposed at a position different from the photographing mask and the two-hole aperture, and the aperture diameter of the variable aperture stop is changed in conjunction with switching from stereo photography to monocular photography. Therefore, it is possible to prevent the reflected light from the crystalline lens or cornea of the eye to be examined resulting from the aberration of the entrance pupil position from being mixed into the fundus image, and a good fundus without ring-shaped flare around the fundus image Images can be acquired.

1 is an optical diagram showing an overall configuration of an ophthalmologic photographing apparatus. FIG. 2 is an optical diagram showing a basic optical configuration when performing stereo shooting with the optical arrangement of FIG. 1. It is the optical figure which showed the state from which the aperture diameter of the variable aperture stop changes at the time of stereo imaging | photography and monocular imaging | photography. (A) is explanatory drawing which showed the state in which ring-shaped flare generate | occur | produces around a fundus image, (b) is explanatory drawing which showed the fundus image without ring-shaped flare.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. In the following embodiments, description will be made by taking a fundus camera as an example of an ophthalmologic photographing apparatus.

  FIG. 1 shows a fundus camera 10 capable of performing stereo photography (stereo photography) and monocular photography (monaural photography). FIG. 1 is drawn centering on stereo photography. In monocular photography, the optical elements are switched to corresponding ones.

  The fundus camera 10 is provided with an illumination optical system that illuminates the fundus and an optical system that images the illuminated fundus. In the illumination optical system, the light emitted from the light source 11 such as a halogen lamp and the light reflected by the concave mirror 12 become infrared light through the visible cut infrared transmission filter 13 that can be inserted into and removed from the optical path, and pass through the strobe 14. Then, the light is incident on the diffusion plate 15 and diffused, and illuminates the ring slit 16 for stereo photography arranged at a position conjugate with the anterior eye portion (pupil) 1b of the eye 1 to be examined. The ring slit 16 is switched to a monocular ring slit 16 'during monocular photography.

  The illumination light that has passed through the ring slit 16 passes through the lens 17, the black dot plate 18 for removing the reflection of the objective lens 22, the half mirror 19, and the relay lens 20, and has a perforated total reflection mirror 21 with a hole in the center. Reflected by. The black spot plate 18 is for stereo photography, and is switched to the black spot board 18 'for monocular photography at the time of monocular photography.

  The illumination light reflected by the perforated total reflection mirror 21 passes through the objective lens 22 and enters the fundus 1a from the anterior eye portion 1b of the eye 1 to be examined, and illuminates the fundus 1a with infrared light.

  The reflected light from the fundus 1a is received through the objective lens 22, passes through the hole of the perforated total reflection mirror 21, and is arranged in a circular shape 2 arranged at a position substantially conjugate with the anterior eye portion 1b of the eye 1 to be examined. The light enters the two-hole aperture 31 as an imaging aperture having two holes 31a and 31b, and the optical path is divided into left and right. In the case of monocular imaging, a single-hole aperture 31 ′ is inserted in the optical path at the anterior segment conjugate position instead of the 2-hole aperture 31.

  During stereo shooting, a pair of left and right light beams from the fundus 1a with the optical path divided is incident on the focus lens 32. The focus lens 32 is movable along the photographic optical axis and corrects the shift of the fundus imaging position due to individual differences in eye diopter. The focus lens 32 is composed of lenses 32a and 32b, and is located between the lenses 32a and 32b. A variable aperture stop 32c is disposed. As will be described later, the variable aperture stop 32c has a smaller aperture diameter in monocular photography than in stereo photography and prevents ring-shaped flare from occurring around the fundus image.

  The fundus image that has passed through the focus lens 32 passes through the imaging lens 33, is reflected by the half mirror 34, is placed at a position conjugate with the fundus 1a, and is red via the imaging masks 42 and 43 that define the imaging range of the fundus. The light is incident on the external transmission visible reflection mirror (light path dividing means) 36. The focus lens 32 and the imaging lens 33 constitute a first imaging optical system that forms a pair of left and right fundus images with parallax via the two-hole aperture 31 as intermediate images at the position of the photographing mask 43. .

  The photographing mask 42 is a photographing mask for monocular photography, the photographing mask 43 is a photographing mask for stereo photography, the photographing mask 43 is inserted into the optical path during stereo photography, and the photographing mask 43 is detached from the optical path during monocular photography. Thus, the photographing mask 42 becomes effective.

  The infrared light that has passed through the infrared transmission visible reflection mirror 36 is reflected by the mirror 38, passes through the lens 37, and enters an imaging device (imaging means) 40 that includes an infrared CCD having sensitivity to infrared light. The signal is input to the monitor 41.

  A relay lens 47 is arranged to connect the exit pupil image of the first imaging optical system to a second imaging optical system described later. Visible light reflected by the mirror 36 is incident on the two-hole aperture 50 disposed at a conjugate position with the anterior eye portion 1b via the relay lens 47, and close to the two-hole aperture 50 (that is, the two-hole aperture 50). A pair of optical path splitting lenses 51 and 52 are arranged (at a position substantially conjugate with 31). As will be described later, the pair of optical path dividing lenses divides the optical path from the photographing mask 43 and separates the left and right fundus images formed as intermediate images at the position of the photographing mask 43 so as not to overlap each other. Thus, a second imaging optical system for re-imaging is configured. Here, the optical path splitting lenses 51 and 52 are optimally arranged at equal intervals with respect to the photographing optical axis 48, that is, axially symmetrical with respect to the photographing optical axis 48.

  An imaging surface 53a of an imaging device (imaging means) 53 composed of a visible CCD having sensitivity to visible light is disposed on the imaging surface by the second imaging optical system, and the optical path splitting lenses 51 and 52 and the imaging are taken. A return mirror 60 is disposed between the elements 53. When the visible cut infrared transmission filter 13 is detached from the optical path and the return mirror 60 is inserted into the optical path, the pair of left and right fundus images separated by the eyepiece (binocular observation means) 62 through the mirror 61 is visually observed. Can be observed.

  The fundus image picked up by the image pickup device 53 can be stored in the memory 54, and is taken into an external personal computer (not shown), displayed on the monitor 41, or outputted to a printer (not shown). .

  The pair of optical path dividing lenses 51 and 52 having the same magnification can be switched to another pair of optical path dividing lenses 51 'and 52' having different magnifications, and a pair of fundus images can be taken at different magnifications. When the pair of optical path splitting lenses 51 ′ and 52 ′ having different magnifications are switched, the photographing mask 43 for stereo photographing is also switched to the photographing mask 43 ′ having a different opening.

  At the time of monocular imaging, a monocular imaging imaging lens 55 is inserted into the optical path instead of the optical path dividing lenses 51 and 52, and the two-hole aperture 50 is detached from the optical path.

  Further, the illumination optical system is provided with a focus dot light source 30, and a light beam from the light source 30 is incident on the fundus 1 a via the half mirror 19, and the focus dot position changes according to the movement of the focus lens 32. The examiner can focus on the fundus of the eye to be examined by observing the focus dot.

  Further, since the anterior eye lens 44 is inserted in the initial stage of alignment, the examiner can confirm the image of the anterior eye part 1b of the eye 1 to be examined on the monitor 41. Further, at the time of alignment or focusing operation, any one of the internal fixation lamps 45 composed of a plurality of LED light sources 45a is turned on, and the examiner causes the subject to gaze at this fixation lamp, The imaging range on the retina of the eye to be examined can be determined, and alignment and focusing operations can be ensured.

  FIG. 2 shows a main part of an optical system that forms a fundus image when performing stereo photography. The same elements as those in FIG. 1 are denoted by the same reference numerals.

  1 and 2, the position conjugate with the fundus 1a of the eye 1 to be examined is indicated by R, and the position conjugate with the anterior eye part (particularly the pupil) is indicated by P.

  1 and 2, the two-hole apertures 31 and 50 and the optical path dividing lenses 51 and 52 are illustrated so as to divide the optical path vertically in the drawing. In the direction perpendicular to). However, since it is difficult to illustrate the state in which the light beam is split in the left-right direction in the drawings, in FIGS. 1 and 2, the two-hole apertures 31 and 50 and the optical path splitting lenses 51 and 52 are perpendicular to the paper surface for convenience. The figure when viewed from the direction of is shown.

  In the fundus camera configured as described above, since the visible cut infrared transmission filter 13 is inserted in the illumination optical path, when the halogen lamp 11 is turned on, the fundus is illuminated with infrared light.

  At the time of monocular imaging, the ring slit 16 ', the single hole aperture 31', and the imaging lens 55 for monocular imaging are inserted into the optical path, and the imaging mask 43, the 2-hole aperture 50, and the like are detached from the optical path.

  The fundus image illuminated with the infrared light is imaged at the position of the photographing mask 42 by the objective lens 22, the focus lens 32, and the imaging lens 33, passes through the infrared transmission visible reflection mirror 36, and is formed by the imaging lens 37. Since the image is re-imaged on the imaging surface of the image sensor 40 as a moving image, the fundus image is displayed on the monitor 41 as a black and white image. As shown in A in the upper right of FIG. Can be observed with non-mydriatic eyes. At this time, if the imaging magnification on the image sensor 40 is set lower than the imaging magnification by the second imaging optical system, a wide-angle fundus image can be observed, and alignment at the time of non-mydriatic pupil Can be easily. In addition, by observing the focus dot from the light source 30, it is possible to focus on the fundus of the eye to be examined.

  In the initial stage of alignment, since the anterior segment lens 44 is inserted, the examiner performs alignment by observing the image of the anterior segment 1b of the eye 1 to be examined with the monitor 41.

  During such monocular photography, as shown in FIG. 4A, a ring-shaped flare 100 a may occur around the fundus image 100 that is photographed or observed on the monitor 41. The cause is considered to be that the reflected light from the crystalline lens or cornea of the eye 1 to be examined resulting from the aberration of the entrance pupil position is mixed into the fundus image.

  Therefore, in the present embodiment, as shown in FIG. 3, positions different from the single hole stop 31 ′ (two hole stop 31 in stereo shooting) and the shooting mask 42 (shooting mask 43 in stereo shooting), for example, a single hole stop. A variable aperture stop 32c having a variable aperture diameter is disposed between the lenses 32a and 32b of the focus lens 32 disposed between 31 'and the photographing mask 42.

  The aperture diameter of the variable aperture stop 32c is changed so that the size of the aperture diameter at the time of monocular photography (upper part of FIG. 3) is smaller than the size of the aperture diameter at the time of stereo photography (lower part of FIG. 3). Therefore, at the time of monocular imaging, the aperture diameter of the variable aperture stop 32c is reduced, and the above-described reflection light from the crystalline lens or cornea of the eye to be examined can be reduced in the fundus image, as shown in FIG. 4B. As described above, a good image having no flare around the fundus image 100 can be obtained.

  The variable aperture stop 32c is disposed between the lenses 32a and 32b constituting the focus lens 32. When the focus lens 32 is moved in the axial direction according to the eye diopter during focusing operation, the variable aperture stop 32c is also changed. Simultaneously moving in the axial direction, it is possible to check on the monitor 41 whether or not flare has occurred around the fundus image 100 during the focusing operation. In the case where the focus lens 32 is composed of two or more lenses, the variable aperture stop 32c is arranged between two predetermined lenses among the plurality of lenses.

  When the alignment and focusing operations are completed, the shutter switch 46 is operated, the shutter operation signal is input to the image sensor 53 and the memory 54, the image sensor 53 is activated, and a fundus still image capturing operation is started. In synchronization with the operation signal of the shutter switch 46, a signal for instructing light emission is transmitted from the image sensor 53 to the strobe 14, so that the strobe 14 emits light. The fundus illuminated by the flash 14 is imaged as a still image by the image sensor 53. Similar to the fundus image observed on the monitor 41, the photographed still image is a good fundus image having no ring-like flare around it.

  At the time of stereo photography, the ring slit 16, the single hole stop 31 ′, and the imaging lens 55 are replaced with the ring slit 16, the two hole stop 31, and the optical path splitting lenses 51 and 52 into the optical path. A photographing mask 43 is inserted into the optical path. Further, as shown in the lower part of FIG. 3, the variable aperture stop 32 c has a larger opening diameter than that of the monocular photographing.

  The light beam from the fundus 1a is divided into right and left by the two-hole aperture 31, and is imaged at the position of the photographing mask 43 as a pair of left and right intermediate images with parallax by the focus lens 32 and the imaging lens 33. An image is observed by the monitor 41. When the fundus is in focus, the pair of fundus images formed at the position of the photographing mask 43 are displayed on the monitor 41 as a single fundus image, so that the pair of fundus images are shifted and doubled. When displayed as an image, it indicates that the fundus is not in focus. Therefore, in this case, the focus lens 32 is adjusted to focus again so that the double image is eliminated.

  A pair of left and right fundus images with parallax imaged at the position of the photographing mask 43 passes through the relay lens 47 and the two-hole aperture 50 and enters the optical path dividing lenses 51 and 52, and enters one hole of the two-hole aperture 31 The image 31 a is formed in the vicinity of the optical path dividing lens 52, and the image of the other hole 31 b is formed in the vicinity of the optical path dividing lens 51. Further, the light beams 51b and 52b passing through the lens centers 51a and 52a of the optical path dividing lenses 51 and 52 through the center of the photographing mask 43 reach the points 51c and 52c on the imaging surface 53a. The distance between the arrival points 51c and 52c is set to a length equal to a distance approximately half of the entire length L of the imaging surface 53a along the direction orthogonal to the imaging optical axis 48 (vertical direction in FIG. 2). The fundus image formed by the optical path dividing lens 51 with the fundus image of FIG. 5 is not superimposed on the upper half of the imaging surface 53a, and the fundus image formed by the optical path dividing lens 52 is not superimposed on the lower half of the imaging surface 53a. Therefore, it is possible to acquire a fundus image for stereoscopic viewing that is separated and imaged and effectively uses the entire imaging surface 53a.

  When the visible cut infrared transmission filter 13 is detached from the optical path and the return mirror 60 is inserted into the optical path, as shown in FIG. 1, the fundus image with a pair of left and right parallax separated by the optical path splitting lenses 51 and 52 is obtained. The eyepiece 62 can be observed through the mirror 61. At this time, the observed fundus image is a separated pair of left and right fundus images 1c and 1d as shown by B in the upper right of FIG. 1, and the examiner can stereoscopically view the fundus. .

  When an image is picked up by the image pickup device 53, the shutter switch 46 is operated. In synchronization with this operation, the return mirror 60 is removed from the optical path, and the strobe 14 emits light. A pair of right and left fundus images 1 c and 1 d separated by light emission of the strobe 14 are imaged by the image sensor 53.

  As shown in the lower part of FIG. 3, the variable aperture stop 32c has a larger aperture size than the aperture size at the time of monaural shooting as shown in the lower part of FIG. Does not occur, and a good stereoscopic fundus image is acquired.

  The pair of fundus images captured in this way are stored in the memory 54 and can be read later and stereoscopically viewed by the stereoscopic device.

  As shown in FIG. 1, the pair of optical path splitting lenses 51 and 52 can be switched to another pair of optical path splitting lenses 51 'and 52' having different magnifications. In this case, a pair of fundus images with reduced or enlarged parallax are captured. At this time, in conjunction with the switching, the photographic mask 43 is switched to the photographic mask 43 ′ having an opening enlarged or reduced according to the magnification.

  In stereo shooting, as shown in the lower part of FIG. 3, the holes 31 a and 31 b of the two-hole aperture 31 are offset from the shooting optical axis 48, so that the fundus conjugate plane R is shifted from the shooting mask 43. As a result, the fundus is also displaced from the imaging surface of the CCD 53, so that the fundus cannot be captured clearly.

  Therefore, in the present invention, an optical element (not shown) that corrects an optical path length deviation during stereo shooting is inserted between the optical path splitting lenses 51 and 52 and the CCD 53. Accordingly, even when switching from monocular photography to stereo photography, the CCD 53 can photograph a pair of fundus images for stereoscopic viewing in focus.

DESCRIPTION OF SYMBOLS 1 Eye to be examined 21 Perforated total reflection mirror 22 Objective lens 31 Two-hole aperture 31 'Single-hole aperture 32 Focus lens 32c Variable aperture stop 33 Imaging lens 40 Imaging element 42, 43 Shooting mask 46 Shutter switch 47 Relay lens 50 Two-hole aperture 51, 52 Optical path dividing lens 53 Image sensor 55 Imaging lens for monocular photography 62 Eyepiece

Claims (4)

A eye bottom photographing apparatus capable of photographing by switching stereo photography and monocular photography by an electronic image pickup means fundus,
A two-hole aperture that is disposed at the anterior ocular segment conjugate position of the eye to be examined and divides the reflected light beam from the eye fundus of the eye into a pair of right and left light beams with parallax;
An imaging optical system that forms a pair of left and right fundus images as an intermediate image from the divided luminous flux;
A pair of optical path splitting lenses that separates the pair of fundus images formed as the intermediate image into left and right images and re-images them on the imaging surface of the electronic imaging means;
An imaging mask that defines an imaging range of the fundus disposed on the surface on which the intermediate image is formed;
A variable aperture stop having a variable aperture diameter disposed at a position different from the photographing mask and the two-hole aperture,
In conjunction with switching from stereo shooting to monocular shooting, the two-hole aperture is switched to a single-hole aperture, the pair of optical path splitting lenses is switched to a single imaging lens, and the aperture diameter of the variable aperture stop is changed. A fundus photographing apparatus characterized in that the fundus photographing apparatus is provided.   The imaging optical system includes a focus lens that is moved in the optical axis direction according to the eye diopter to form an in-focus intermediate image, and the variable aperture stop is configured to emit light simultaneously with the focus lens. The fundus imaging apparatus according to claim 1, wherein the fundus imaging apparatus is moved in an axial direction.   The fundus imaging apparatus according to claim 2, wherein the focus lens includes a plurality of lenses, and the variable aperture stop is disposed between the plurality of lenses. It said variable aperture stop, the size of the opening diameter at the time of stereo photography, fundus shooting apparatus according to any one of claims 1 to 3, characterized in that larger than the size of the opening diameter of the monocular photography.

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