JP2006087793A - Ophthalmic imaging equipment - Google Patents

Abstract

Provided is a fundus imaging apparatus that can reduce the size and cost of the apparatus with a simple structure, can be optically adjusted easily, and can perform simultaneous stereoscopic imaging of the fundus.
A two-hole diaphragm 10 having two openings 10a and 10b is arranged at a position substantially conjugate with an anterior eye portion of an eye to be examined, and a lenticular prism 15 or a lenticular lens close to an imaging surface of a stereoscopic imaging CCD 16. Is placed. The exit pupil position of the imaging lens 12 that forms an image of the fundus on the stereoscopic imaging CCD is set to be infinite, so that the light flux that has passed through the imaging lens becomes substantially parallel and is taken through the lenticular prism. The light incident on one pixel column of the CCD is only light that has passed through one of the two apertures of the two-hole aperture, and the light from both apertures enters each pixel column of the CCD for photographing. It is made to inject alternately.
[Selection] Figure 2

Description

  The present invention relates to an ophthalmologic photographing apparatus, and more particularly to an ophthalmic photographing apparatus capable of simultaneously photographing left and right images for stereoscopic viewing of the fundus of a subject's eye.

  In the conventional simultaneous stereoscopic fundus camera, as described in Patent Documents 1 and 2 below, the left and right images are positioned at a position conjugate with the anterior eye portion of the eye to be examined (conjugated with the pupil) with respect to the objective lens. A two-hole aperture having two left and right holes (openings) is provided, and each light beam from the fundus that has passed through the two holes is divided into two optical paths by a prism or the like, and a pair of right and left links The image is guided to each of the image optical systems, and is imaged on the film surface or on the left and right separate areas of the image pickup surface of the image pickup device or on the left and right image pickup devices.

  In addition, the shape of the two apertures of the pupil-conjugated two-hole aperture for stereoscopic shooting is made into a vertically long rectangle (Patent Document 3), or a fundus image is alternately incident on the pixels of the image sensor using a cylindrical lens. (Patent Document 4), the diaphragm of the fundus conjugate position and the pupil conjugate position is made variable to enable stereoscopic shooting and monocular shooting on the same video medium (Patent Document 5).

Further, the left-eye and right-eye guidance images are stereoscopically viewed through alternating pixels of the image sensor via a prism or the like (Patent Documents 6 and 7).
Japanese Patent No. 2644217 Japanese Patent No. 2933995 Japanese Patent No. 3255730 Japanese Patent Laid-Open No. 10-165372 Japanese Patent Laid-Open No. 11-299739 Japanese Patent Laid-Open No. 9-18896 JP-A-9-212388

  However, in the conventional configurations such as Patent Documents 1, 2, and 3, it is necessary to dispose each lens of the pair of left and right imaging optical systems in two right and left optical paths, so the configuration is complicated and the apparatus becomes large. At the same time, the cost becomes high. In addition, there is a problem that the optical adjustment of the two left and right optical paths is very complicated and takes time to adjust. In addition, since the left and right images are separately formed on the left and right regions or elements, there is a problem that it is necessary to accurately align the left and right images later.

  Further, in the configuration of Patent Document 4 and the like, two images (right image and left image) from the two-hole aperture are made to enter the pixels alternately in the image pickup device. The right image and the left image are incident, and there is a problem that good stereoscopic viewing cannot be performed.

  Therefore, the present invention solves the above-described problems, and can reduce the size and cost of the apparatus with a simple structure, and can easily perform optical adjustment, so that fundus photographing can be performed satisfactorily. It is an object to provide an apparatus.

The invention for solving the above problems is as follows.
In an ophthalmologic photographing apparatus comprising: an optical system that forms an image of the fundus of the eye to be examined; and an imaging unit having pixels in a matrix arrangement arranged at the image formation position of the fundus image by the optical system.
In the optical system, a lens movable in the direction of the optical axis is arranged to correct a shift in the imaging position due to individual differences in the eye diopter,
A diaphragm having two openings is arranged at a position substantially conjugate with the anterior segment of the eye to be examined,
Providing a deflection optical element close to the imaging surface of the imaging means,
The exit pupil position of the optical system is set to be infinite, and light incident on one pixel column of the imaging means via the deflection optical element is one of the two apertures of the diaphragm. In this case, only the light that has passed through the aperture and the light from both apertures are alternately incident on each pixel column of the imaging means.

The present invention also provides:
A first optical system that forms an image of the fundus of the eye to be examined; a field stop disposed at a fundus conjugate position of the first optical system; and a second image that re-forms a fundus image formed in the vicinity of the field stop. An ophthalmologic photographing apparatus having an optical system and an imaging unit having pixels in a matrix arrangement arranged at a re-imaging position of a fundus image by the second optical system,
In the first optical system, a lens that is movable in the direction of the optical axis in order to correct a shift in the imaging position due to individual differences in the eye diopter to be examined is disposed,
In or near the second optical system, a diaphragm having two apertures is arranged at a position substantially conjugate with the anterior segment of the eye to be examined,
A deflecting optical element is disposed adjacent to the imaging surface of the imaging means;
The exit pupil position of the second optical system is set to be infinite, and light incident on one pixel row of the imaging means via the deflection optical element is one of the two apertures of the diaphragm. Only light that has passed through one of the apertures is used, and light from both apertures is alternately incident on each pixel column of the image pickup means.

  According to the present invention, since the exit pupil position of the optical system that forms the fundus image on the imaging means for stereoscopic photography is set to be infinite, the light incident angle to the deflecting optical element is constant, Since the image for the left eye and the image for the right eye for stereoscopic shooting are separated into the image sensor and alternately enter the pixel row, the image for the left eye and the image for the right eye are one pixel. There is an advantage that a good stereoscopic image can be obtained without overlapping the rows and entering.

  The present invention is an ophthalmologic photographing apparatus capable of performing stereo photography for stereoscopic viewing, and the present invention will be described in detail based on an embodiment in which the ophthalmologic photographing apparatus is a fundus camera with reference to the accompanying drawings.

  FIG. 1 shows a first embodiment of the present invention. In the fundus camera shown in FIG. 1, an illumination optical system for illuminating the fundus Er of the eye E and an imaging optical system for photographing the illuminated fundus Is provided. In the illumination optical system, the light emitted from the light source 1 such as a halogen lamp and the light reflected by the concave mirror 2 become infrared light through the visible cut infrared transmission filter 3 and pass through the strobe 4 and the condenser lens 5. The stereoscopic slit 6 arranged at a position conjugate with the anterior eye part (pupil) Ep of the eye E is illuminated. The illumination light from the slit 6 passes through the lens 7, is reflected by the perforated total reflection mirror 8 having a hole in the center, passes through the objective lens 9, and passes from the anterior segment Ep of the eye E to the fundus Er. Incident light and illuminate the fundus Er with infrared light.

  The reflected light from the fundus Er passes through the holes of the objective lens 9 and the perforated total reflection mirror 8, and has two holes having two openings arranged at a position P substantially conjugate with the anterior eye part (pupil) of the eye to be examined. The light enters the diaphragm 10 and is separated into a light beam for the right eye and a light beam for the left eye, and then enters the focusing lens 11. The focusing lens 11 is movable along the optical axis, and corrects the shift of the fundus imaging position due to individual differences in the eye diopter.

  The light beam from the fundus subsequently passes through the imaging lens 12 that forms an image on the fundus of the subject, is reflected by the return mirror 13, and is imaged on the fundus by the imaging lens 12, that is, at a position conjugate with the fundus Er. The light enters the observation CCD 14 having sensitivity to the arranged infrared light. When the return mirror 13 leaves the optical path, the light beam from the fundus enters the imaging CCD 16 that is sensitive to visible light as imaging means arranged at a position conjugate with the fundus Er. The imaging CCD 16 has a large number of pixels arranged in a matrix, and a lenticular prism 15 as a deflection optical element is arranged in the vicinity of the imaging surface of the imaging CCD 16.

  In FIG. 1, the two-hole aperture 10 is illustrated so as to divide the light beam vertically in the drawing, and the lenticular prism 15 and the photographing CCD 16 are arranged in a direction perpendicular to the paper surface in FIG. In FIG. 2, the two-hole aperture 10 actually divides the light beam in the left-right direction (the direction perpendicular to the paper surface in FIG. 1), as shown in FIG. Both prism surfaces 15a and 15b extend in a direction perpendicular to the paper surface in FIG.

  Further, the exit pupil position of the imaging optical system (focusing lens 11 and imaging lens 12) is set at or near infinity, and as shown in FIGS. 2 and 3 (FIG. 2). However, for the sake of simplicity, the focusing lens 11 is omitted, or an optical system in which the focusing lens and the imaging lens are integrated may be illustrated as one lens 12), at a substantially pupil conjugate position. A light beam that passes through an aperture 10a of a certain two-hole aperture becomes a substantially parallel light beam after passing through the imaging lens 12 and is incident on one prism surface 15a of the lenticular prism 15, and then the odd-numbered pixels of the photographing CCD 16 The light beam that enters the row (shaded portion) 16a and passes through the aperture 10b of the two-hole aperture becomes the substantially parallel light beam after passing through the imaging lens 12, and the other prism of the lenticular prism 15 After entering the 15b, it will be incident on 16b on the even-numbered pixel columns of the imaging CCD 16. In FIG. 3, a thick solid line portion 15c indicates a light shielding portion.

  Such incident characteristics include, for example, the distance between the two openings 10a and 10b of the two-hole aperture 10, that is, the pupil division distance D is D = 3 mm, the diameters Φ of the openings 10a and 10b are Φ = 0.5 mm, and the image is formed. The focal length f of the lens 12 is f = 20 mm, the photographing CCD 16 is 1/3 inch CCD, and the distance X1 between the two-hole aperture 10 and the imaging lens 12 is substantially f. The distance X2 between the imaging lens 12 and the lenticular prism 15, the photographing CCD 16, and the focal length f is obtained by arranging at or near the focal length of 12. At this time, the angle θ at which the light beam from the imaging lens 12 enters the prism 15 is θ = 4.3 °, and each parallel light beam enters the prism surfaces 15 a and 15 b of the lenticular prism 15 almost perpendicularly. In this way, the prism angle is set. Further, the pixel pitch (pixel width) P1 in the row direction (left-right direction in FIGS. 2 and 3) of the photographing CCD 16 is set to substantially half of the prism pitch (distance between the apexes of the prism) P2 of the lenticular prism 15. The

  In such a configuration, alignment is performed by turning on the light source 1, illuminating the fundus Er of the eye E with infrared light, and guiding the reflected light from the fundus to the observation CCD 14 and observing the image. Further, focusing is performed by moving the focusing lens 11 along the optical axis.

  When the alignment and focusing are completed, the strobe 4 emits light and the return mirror 13 is removed from the optical path. The light beam from the fundus illuminated by the strobe light passes through the hole of the objective lens 9 and the perforated total reflection mirror 8 and enters the two-hole aperture 10 to be converted into the right-eye light beam and the left-eye light beam. After separation, the light enters the focusing lens 11, and the fundus is imaged by the imaging lens 12 on the imaging surface of the imaging CCD 16 via the lenticular prism 15.

  Since the exit pupil position of the optical system comprising the focusing lens 11 and the imaging lens 12 is set at or near infinity, as shown in FIGS. 2 and 3, it passes through the aperture 10a of the two-hole aperture. After passing through the imaging lens 12, the luminous flux becomes a substantially parallel luminous flux, enters the one prism surface 15 a of the lenticular prism 15, and then enters the odd-numbered pixel row 16 a of the photographing CCD 16. Further, the light beam passing through the aperture 10b of the two-hole aperture becomes a substantially parallel light beam after passing through the imaging lens 12, and enters the other prism surface 15b of the lenticular prism 15, and then the even-numbered CCD 16 for photographing. It enters the pixel row 16b. Further, the pixel pitch (pixel width) P1 in the row direction (left-right direction in FIG. 4) of the photographing CCD 16 is half of the prism pitch (distance between the apexes of the prism) P2 of the lenticular prism 15. One pixel row Rj (j = 1 to n) of the CCD 16 is only light that has passed through the opening 10a of the two-hole aperture 10, and no light that has passed through the other opening 10b is incident on the pixel row Rj. In the row Lj (j = 1 to n), only the light that has passed through the opening 10b of the two-hole aperture 10 is obtained, and the light that has passed through the other opening 10a is not incident. In addition, light from both the openings 10a and 10b is incident on the pixel rows Rj and Lj alternately.

  The image distribution on the imaging surface of such a photographing CCD 16 is shown in FIG. 4, and R1, R2,. . . . . Rn is an odd-numbered pixel row 16a, and L1, L2,. . . . . Ln is an even-numbered pixel column, and each pixel has a width of P1 in the row direction.

  Further, a lenticular lens 20 as shown in FIG. 5 can be used instead of the lenticular prism 15. This lenticular lens 20 is a lens in which the semicylindrical lenses 20a extending perpendicularly to the paper surface in FIG. 5 are arranged in the left-right direction at a pitch P2 (twice the pixel pitch P1) and pass through the opening 10a of the two-hole aperture 10. The light beam passes through the imaging lens 12 to become a substantially parallel light beam, is refracted by the semi-cylindrical lens 20a of the lenticular lens 20, and is condensed on the pixel row 16a of the photographing CCD 16, and the aperture of the aperture stop 10 is opened. The light beam that has passed through 10b passes through the imaging lens 12 to become a substantially parallel light beam, and is condensed by the same semi-cylindrical lens 20a onto the pixel row 16b on the left side of the pixel row 16a of the photographing CCD 16, and the lenticular prism 15 The same effect can be obtained.

  The image captured by the photographing CCD 16 can be stereoscopically displayed on a display means such as a commercially available lenticular monitor or a parallax barrier monitor, or can be stereoscopically viewed using polarized glasses.

  In addition, the specifications of each of the optical elements described above assume a pupil imaging magnification of about 1. Under this condition, the field of view is an imaging range of about 10 degrees, and the depression of the optic nerve head is stereoscopically viewed. Can be an effective means of diagnosing glaucoma.

  FIG. 6 shows another embodiment, in which monocular photography and stereoscopic photography are possible.

  In FIG. 6, the light emitted from the light source 30 such as a halogen lamp and the light reflected by the concave mirror 31 become infrared light through the visible cut infrared transmission filter 32 and pass through the strobe 33 before the eye E to be examined. The ring slit 34 arranged at a position conjugate with the eye part (pupil) Ep is illuminated. The ring slit 34 is switched to a three-dimensional illumination stop 34 'during stereoscopic shooting. Illumination light from the ring slit 34 or the illumination stop 34 'passes through the lens 35, the black spot plate 36, and the relay lens 37, and is reflected by a perforated total reflection mirror 39 having a hole in the center, and then passes through the objective lens 38. Then, the light enters the fundus Er from the anterior segment Ep of the eye E and illuminates the fundus Er with infrared light.

  The reflected light from the fundus Er is received through the objective lens 38, passes through the hole of the perforated total reflection mirror 39, and enters the photographing aperture 40 disposed at a position P conjugate with the anterior eye part (pupil) Ep. Then, it passes through the lens 41 and the focusing lens 42. The focusing lens 42 is movable along the optical axis, and corrects the shift of the fundus imaging position due to individual differences in the eye eye diopter. Note that the photographing aperture 40 is switched to a photographing aperture 40 'for stereoscopic shooting during stereoscopic shooting.

  The light flux from the fundus subsequently passes through the lens 43, is reflected by the mirror 44, enters the infrared reflection visible transmission mirror 46 via the field stop 45 disposed at a position R conjugate with the fundus Er, and is red. The infrared light reflected by the external reflection visible transmission mirror 46 passes through the imaging lens 47 and enters the observation CCD 48 as an imaging means having sensitivity to the infrared light, while the visible light transmitted through the mirror 46. Is reflected by the return mirror 49, passes through the imaging lens 50, and enters the monocular imaging CCD 51 as imaging means having sensitivity to visible light.

  During stereoscopic shooting, the return mirror 49 leaves the optical path, and the visible light transmitted through the mirror 46 is reflected by the mirror 52 and passes through the two-hole aperture 53 arranged at a position P conjugate with the anterior eye (pupil) Ep. Then, the light enters the imaging lens 54, enters a stereoscopic photographing CCD 55 as an imaging means having sensitivity to visible light, and a lenticular prism 56 as a deflection optical element is disposed in the vicinity of the imaging surface of the stereoscopic photographing CCD 55. Is done. The two-hole aperture 53, the lenticular prism 56, and the stereoscopic photographing CCD 55 correspond to the two-hole aperture 10, the lenticular prism 15, and the photographing CCD 16 of the first embodiment, respectively.

  In such an imaging optical system, the position conjugate with the fundus Er of the eye E is indicated by R, and the position conjugate with the anterior eye part (particularly the pupil) Ep is indicated by P. The objective lens 38 and the lens 41 are shown. , 43 and the like constitute a first optical system that forms an image of the fundus of the subject's eye on the field stop 45, and the imaging lenses 50 and 54 form an image near the field stop 45 by the first optical system. A second optical system for re-imaging the fundus image thus formed on the CCD 51 for monocular photography and the CCD 55 for stereoscopic photography is constructed. When the stereoscopic imaging CCD 55 is the first image pickup means, the return mirror 49 is an optical path dividing means arranged between the field stop 45 and the first image pickup means. From the eye to be examined according to the position of the return mirror 49. Are switched and selected and guided to the first imaging means or the monocular imaging CCD (second imaging means) 51.

  With such a configuration, since an infrared image of the fundus is formed on the observation CCD 48, the image of the observation CCD 48 is observed on a monitor (not shown), and alignment and focusing operations are performed.

  When alignment and focusing are completed, the strobe 33 emits light, and at the time of monocular photography, the ring slit 34, the photographing aperture 40, and the return mirror 49 are in the optical path, and the luminous flux from the fundus is incident on the monocular photographing CCD 51 and the fundus is monocularly photographed. The image is taken by the CCD 51.

  On the other hand, at the time of stereoscopic shooting, the return mirror 49 is detached from the optical path. At that time, the illumination diaphragm is switched to the slit 34 ′, the imaging diaphragm is switched to the stereoscopic imaging diaphragm 40 ′, and the luminous flux from the fundus is changed to the two-hole diaphragm 53. Are split into a left eye light beam and a right eye light beam, and each light beam is imaged on the stereoscopic photographing CCD 55 via the lenticular prism 56, and a three-dimensional image of the fundus is photographed.

  The exit pupil position of the second optical system composed of the imaging lens 54 is set at or near infinity as in the optical system of the imaging lens 12 of the first embodiment. After passing through the imaging lens 54, the light beam passing through the aperture becomes a substantially parallel light beam, enters one prism surface of the lenticular prism 56, and then enters the odd-numbered pixel row of the stereoscopic CCD 55. The light beam passing through the other aperture of the two-hole aperture 53 passes through the imaging lens 54 and then becomes a substantially parallel light beam. After entering the other prism surface of the lenticular prism 56, the even-numbered CCD 55 for stereoscopic photography 55 Incident on the pixel column. This relationship corresponds to that shown in FIG. 3 in which the lenticular prism 15 is replaced with the lenticular prism 56, and the photographing CCD 16 is replaced with the stereoscopic photographing CCD 55. Similarly to the first embodiment, the stereoscopic photographing CCD 55 is arranged in the row direction. Since the pixel pitch (pixel width) P1 is substantially half of the prism pitch (distance between the apexes of the prism) P2 of the lenticular prism 56, the two-hole aperture 53 is included in one pixel row of the stereoscopic photographing CCD 55. Only the light that has passed through one of the apertures of the second aperture, and the light that has passed through the other aperture does not enter, and the light from both apertures of the two-hole aperture 53 alternately enters each pixel column. This relationship is also the same as that of the first embodiment, and the same effect as that of the first embodiment is obtained.

  Also in the second embodiment, as in the first embodiment, the lenticular lens 20 as shown in FIG. 5 can be used instead of the lenticular prism 56.

  In addition, the image captured by the stereoscopic CCD 55 can be stereoscopically displayed on a display means such as a commercially available lenticular monitor or a parallax barrier monitor, or can be stereoscopically viewed using polarized glasses. Similar to Example 1.

1 is an optical diagram showing an optical system of a first example of an ophthalmologic photographing apparatus. It is explanatory drawing explaining the state in which the light beam which passes the opening of a two-hole aperture is incident on the photographing CCD. FIG. 3 is an enlarged view of portions of a lenticular prism and a photographing CCD in FIG. 2. It is explanatory drawing which showed incidence | injection of the light ray in each pixel row | line | column of CCD for imaging | photography. FIG. 4 is an enlarged view corresponding to FIG. 3 when a lenticular lens is used. It is the optical diagram which showed the optical system of the 2nd Example of the ophthalmologic imaging device.

Explanation of symbols

10 Two-hole aperture 15 Lenticular prism 16 CCD for shooting
20 Lenticular lens 40 Shooting diaphragm 45 Field diaphragm 51 Monocular CCD
53 Two-hole aperture 55 Stereo CCD
56 Lenticular prism

Claims (4)

In an ophthalmologic photographing apparatus comprising: an optical system that forms an image of the fundus of the eye to be examined; and an imaging unit having pixels in a matrix arrangement arranged at the image formation position of the fundus image by the optical system.
In the optical system, a lens movable in the direction of the optical axis is arranged to correct a shift in the imaging position due to individual differences in the eye diopter,
A diaphragm having two openings is arranged at a position substantially conjugate with the anterior segment of the eye to be examined,
Providing a deflection optical element close to the imaging surface of the imaging means,
The exit pupil position of the optical system is set to be infinite, and light incident on one pixel column of the imaging means via the deflection optical element is one of the two apertures of the diaphragm. The ophthalmologic photographing apparatus is characterized in that only the light that has passed through the aperture and light from both apertures alternately enter each pixel row of the imaging means. A first optical system that forms an image of the fundus of the eye to be examined; a field stop disposed at a fundus conjugate position of the first optical system; and a second image that re-forms a fundus image formed in the vicinity of the field stop. An ophthalmologic photographing apparatus having an optical system and an imaging unit having pixels in a matrix arrangement arranged at a re-imaging position of a fundus image by the second optical system,
In the first optical system, a lens that is movable in the direction of the optical axis in order to correct a shift in the imaging position due to individual differences in the eye diopter to be examined is disposed,
In or near the second optical system, a diaphragm having two apertures is arranged at a position substantially conjugate with the anterior segment of the eye to be examined,
A deflecting optical element is disposed adjacent to the imaging surface of the imaging means;
The exit pupil position of the second optical system is set to be infinite, and light incident on one pixel row of the imaging means via the deflection optical element is one of the two apertures of the diaphragm. An ophthalmologic photographing apparatus characterized in that only light that has passed through one opening is provided, and light from both openings is alternately incident on each pixel row of the imaging means.   The image pickup means is a first image pickup means, an optical path dividing means is provided between the field stop and the first image pickup means, and a second image pickup means is provided in the divided optical path. The ophthalmologic photographing apparatus according to 2.   The optical path splitting means is an optical path selection switching means that selectively guides light from the eye to be examined to the first or second imaging means, and a ring slit provided in the illumination optical system according to the selection, The ophthalmologic photographing apparatus according to claim 2 or 3, wherein a diaphragm that is substantially conjugated to an anterior eye part disposed in or near one optical system is switched.