JPS6018154A - Observation device of eyeground camera - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides the following methods: prior to focusing using a beam that does not cause pupil contraction reaction like infrared rays, and then photographing using visible light like strobe light, The present invention relates to a photographing method using a non-mydriatic fundus camera that takes into account initial positioning of the fundus camera with respect to the eye to be examined, that is, pupil positioning.

Conventional fundus cameras use visible light to focus, determine the field of view, and take pictures, which causes the inconvenience of pupil constriction in the eye being examined. To avoid this, it is necessary to avoid using mydriatic agents. It didn't happen. However, this mydriatic agent not only causes great discomfort to eye function, but also has the risk of inducing latent glaucoma, and therefore, a fundus photography method that does not use a mydriatic agent is desired. A fundus camera that uses invisible light to adjust the focus of the pupil in a naturally mydriatic state without using a mydriatic agent is described in Japanese Patent Publication No. 39-14413. This fundus camera illuminates the fundus with infrared rays during focus adjustment, and observes this using an image tube combined with a photographing optical system. Focus adjustment is performed by adjusting the photographing optical system while observing the fundus image displayed on the image tube. However, although there is no need to use mydriatics with this camera, the focus adjustment is done by setting a focus target on the fundus image displayed on the image tube and using the sharpness of this as a guide, so it is difficult to adjust the focus based on the hue of the fundus. Contrast is difficult to obtain and camera operation is difficult and requires skill. On the other hand, before focusing or photographing, a fundus camera
It is necessary to perform pupil positioning to align the position of the objective lens with respect to the pupil of the eye to be examined. When shining bright observation light from the objective lens toward the eye being examined, as with a conventional fundus camera,
The examiner directly compares the light source, which is an image of the ring slit, with the pupil of the eye to be examined from the side of the fundus camera, moves the fundus camera, and aligns the objective lens with respect to the pupil.

However, when using a beam that does not reduce the pupil during observation, it is difficult for the examiner to visually recognize the image of the ring slit, so the pupil positioning method described above is not used.

It cannot be used.

The purpose of the present invention is to provide an observation device for a fundus camera that can perform fundus observation and pupil observation of an eye to be examined. Fundus and pupil images.

FIG. 1 shows an optical system according to an embodiment of the present invention.

In the figure, 1 is an objective lens, 2 is a relay lens, 3 is a film surface, and 4 is an aperture stop, and these four components constitute a photographing system. E is an eyeball placed at a predetermined position in front of the fundus camera. An image of the fundus Ef of this eyeball E is formed as an aerial image by an objective lens l, and a relay lens 2 transfers this aerial image to a film plane 3 and a reversing mirror. Film plane 3 regarding 28
The image is re-imaged on a symmetrical plane F3 (described later). A color film or the like is placed on the multi-ilm surface 3 to record the fundus Ef image. 5 is a focus indicator light source, 6 is an aperture stop, 7 is a condenser lens, 8 is an infrared transmitting visible light reflecting filter,
9 is the split image prism, 10 is the focus index (
In this example, it is a thin line-shaped slit as shown in FIG. 2), 11 is Surin I (in this example, it is a two-hole slit as shown in FIG. 2), 12if relay lens,
13 is an optical path splitting means (in this example, it is shown in FIG. 2,
14 is a partially reflective transparent plate made of a transparent plate with a reflective film 13' applied to a small area), and the relay lens 15 is an optical path splitting means (in this example, it is a perforated mirror as shown in FIG. 2). The above 11 members and the objective lens 1 constitute a focus index projection system. In the embodiment of FIG. 1, the relay lens 2.14 is optically equivalent and the perforated mirror 1.
They are arranged symmetrically with respect to 5. The light emitted from the light source 5 passes through an aperture diaphragm 6 and is focused onto a focus index slit 10 by a condenser lens 7. An infrared transmitting and visible light reflecting filter 8 is disposed between the lens 7 and the index 10. Therefore, in the optical path of the focus index projection system after this filter 8, the visible component is removed from the beam and only the infrared beam is left. The beam from the focus index projection system is not sensed. A split image prism 9 (in this example, it has a shape as shown in FIG. 3 and splits one beam into two beams) is placed near the index lO, and therefore the prism 9 and the focus index The infrared beam passing through the slit 10 is divided into two to become a focusing infrared beam Ip. 2-hole slit with light source 5) 1
A perspective view of the arrangement up to 1 is shown in FIG. The relay lens 12 forms an image of the index 10 on a reflective portion 13' of a partially reflective transparent plate 13. This imaging point F1 is arranged to be on a conjugate plane of the film plane 3. (In the example shown, the relay lenses 2 and 14 are optically equivalent and are arranged symmetrically with respect to the perforated mirror.) The infrared beam Ip reflected here passes through the relay lens 14 and passes through the ring slit 2.
7 (described later), is reflected by the perforated mirror 15, and is focused at or near the rear focal point F2 of the objective lens 1. Next, the objective lens 1, the crystalline lens E of the eyeball E! ;L
and is projected onto the fundus Ef. If the focus of the eyeball E is adjusted to infinity and the focusing infrared beam IP is focused on the back focus F2 of the objective lens 1, then
The beam Ip passing through the objective lens 1 becomes a parallel beam of light, and is therefore accurately focused on the fundus Ef, and an image 10' of the focus index 10 is formed on the fundus Ef as shown in FIG. 4A. If the focus index slit 10 cannot be accurately imaged on the fundus due to an abnormality in the refractive power of the eyeball E, the image of the index 10 will be the image of the upper two-hole slit ll as shown in FIGS. 4B and C. The two holes are separated according to the angle at which a point on the fundus Ef is viewed, forming an image like 10''. Beam IP relay lens 14
It is sufficient to move the focal light position by an appropriate distance along the optical axis from the rear focal point F2 of the objective lens l. Here, the two-hole slit 11 is placed at the rear focal position of the relay lens 12, and the two holes are included in the slit portion of the image of a ring slit 27 (described later) formed by the relay lens 14 and the two-hole lens 12. They are arranged so that a straight line connecting the centers of the holes lies on the diameter of the image of the ring slit 27. In addition, the aperture diaphragm 6 has a two-hole slit where the light beam from the index illumination light source 5 is separated into two by the split image prism 9.
The size of the aperture is determined so that the two-hole slit 11 passes through 11 separate holes and does not interfere with each other, and is placed near the position where the image is formed by the two-hole slit 11 or the condenser lens 7.

16 is a light source for fundus illumination, 18 is an infrared transmission visible light reflection filter, 19 is a condenser lens, zO is a reversing mirror, 21 is a strobe light source, 23 is a condenser lens, 25 is a ring slit, 26 is a relay lens, 27
is a ring slit, and the above nine elements, the relay lens 14, the optical path splitting means 15, and the objective lens 1 constitute a fundus illumination system. The light emitted from the fundus illumination light source 16, including a portion of the light reflected by the concave mirror 17, passes through a condenser lens 19, an inverting mirror 20, and a field lens 24, and is collected onto a ring slit 25. Ringsuri Nto 2
The light whose secondary light source is one point on 5 is Ringslint 25.
The relay lens 26 placed so as to have a rear focal point at the intersection with the optical axis of An image is once formed by the lens 14 onto a ring slit 27 placed on its front focal plane, and is reflected by a perforated mirror 15 installed obliquely in the optical path of the photographing system, and is reflected by the objective lens (
1), an image is formed on the pupil of the eye E to be examined and the fundus Ef is illuminated. The ring slit 25 is imaged by the lens 26.14 so that the ring portion coincides with the ring slit 27, and the ring slit 27 is further imaged onto the pupil of the eyeball E by the objective lens l. Between lenses 26 and 14, the illumination beam is a parallel light beam, and between lenses 14 and 2
are optically equivalent and arranged symmetrically with respect to the perforated mirror 15. Therefore, the part of the fundus image formed on the film surface 3 corresponding to the ring center part is dark, and therefore the focus projected on this part is The contrast of the indicators becomes higher. In addition, ring illumination method in the illumination beam optical path)25
, 27, the reflected light of the illumination beam by the objective lens and the cornea is prevented from traveling to the film surface 3 based on the principle of the usual ring illumination method. Furthermore, since the infrared transmitting visible light reflecting filter 18 is disposed between the fundus illumination light @i16 and the condenser lens 19, the light that illuminates the fundus Ef as described above is infrared, and does not affect the eye. Not detected.

After focusing and determining the shooting field, use the reversing mirror 2.
0, the partially reflective transparent plate 13 is indicated by broken lines (20) and (13), respectively.
As shown in FIG. 2, a strobe light source 21. Using a concave mirror 22 and a condenser lens 23, the fundus of the eye is momentarily illuminated and photographed. At this time as well, an infrared filter may be placed in front of the strobe light source 21 and an infrared film may be exposed using infrared rays, but in order to ensure precise examination, color photography is preferable, and therefore, as shown in Figure 1. In the embodiment, no infrared transmitting/visible light reflecting filter is disposed in front of the strobe light source 21.

28 is an optical path splitting means, and in this example, the reversing mirror 30 is a relay lens, 31 is an infrared image pickup tube, and 32 is a monitor television. The above four, the objective lens 1, and the relay lens 2 constitute an observation system. do. When the light from the fundus Ef matches the focus index image Ef of the imaging system, it forms an aerial image at or near the back focal point F2 of the objective lens 1,
Furthermore, the light passes through the hole of the perforated mirror 15 and is re-imaged by the relay lens 2 on the film surface 3 or on the symmetry plane F3 of the film surface 3 with respect to the reversing mirror 28 interposed in the optical path of the photographing system. During the focus adjustment operation, the reversing mirror 28 is placed in the optical path of the photographing system. Therefore, the infrared rays emitted from the focus index photographing system and the fundus illumination system and reflected by the fundus Ef travel backward through the objective lens l, pass through the relay lens 2, are reflected by the reversing mirror 28, and are focused on the symmetry plane F3. The image is then passed through the field lens 29 and relay lens 3.
0, an image is formed on the light receiving surface of the image pickup tube 31.

The infrared imaging tube 31 converts infrared information into an electrical signal and applies it to the monitor television 32. The monitor television 32 converts the electrical signal into a television image and displays the infrared image as a visible image. Instead of the image pickup tube 31 and monitor television 32, other means for converting an infrared image into a visible image, such as an infrared image tube, may be used.

As described above, the focus indicator photographing system and fundus illumination system share an optical path with the photographing system through the perforated mirror 15 and the i-base thread through the reversing mirror 28.

Focus adjustment operations and shooting field determination operations are performed using the reversing mirror 20.
．． 28. The partially reflective transparent plate 13 is arranged in the optical path of the illumination system and imaging system as shown by the solid line in FIG. This is performed by irradiating the fundus Ef with an infrared beam, and visualizing the reflected infrared rays from the fundus Ef using an observation system. An image as shown in FIG. 4 is observed on the image display surface of the monitor 32. To adjust the focus,
For example, as mentioned earlier, two relay lenses 2', 1
4 is optically transparent, so if both lenses 2 and 14 are linked manually or automatically so that when one lens moves, the other lens also moves transparently, the fundus Ef Simply move the relay lens 14 along the optical path so that the index image matches the shape of the index 10.
The movement is optically equivalent to the movement of 4. Therefore, the focus of the photographing system can be brought into exact alignment with the fundus by a simple operation of moving one of the lenses 2, 14 a suitable distance while observing the focus index image displayed on the monitor television 32.

However, if the fundus illumination system and the focus index projection system share the relay lens 14 as in the example in Figure 1, the illumination state of the fundus may change by moving the relay lens 14. Although not shown in the example of FIG. 1, both the film plane 3 and the point F1, which is on the plane conjugate to the film plane 3 where the focus index is once formed as described above, are simultaneously optically moved along the optical path. A mechanical or electrical interlocking means is installed to make the monitor TV 3
The imaging system can be accurately focused on the fundus by simply moving either the film surface 3 or the imaging point F1 by an appropriate distance so that the index image displayed at 2 becomes as shown in FIG. 4A. Therefore, at this time, the imaging system including the plane of symmetry F3, the field lens 29, the relay lens 30, and the image pickup tube 31 is moved simultaneously with the movement of the film surface 3 so as to be optically transparent thereto. The system in which the relay lenses 2 and 14 are moved relative to each other or the focal length is changed does not share the lens 14 with the fundus illumination system or the relay lens, but has a separate optical path adjacent to the optical path of the index projection system, for example. Just do it like this. By thus adjusting the photographing system and the focus index projection system in a correlated manner while observing the focus index image on the monitor television 32, the focus of the photographing system can be aligned with the fundus Ef. In addition, the monitor television 32 displays not only a focus index image but also a fundus image illuminated over a wide range by the fundus illumination system.
Observe this and change the relative direction between the optical axis of the imaging system and the eyeball E, for example, by changing the direction of the camera relative to the fixed eye, or by changing the direction of the eyeball that the subject is gazing at relative to the target eyeball. This allows the field of view to be determined. This is because the optical paths of the observation system and the photographing system are the same (the above-mentioned respective prefectures are assembled into one body, for example, and can be moved and rotated on the camera stand).

By the way, in order not to use a mydriatic agent to open the pupil, the eyeball E must be shielded from visible light when adjusting the focus of the fundus camera and determining the photographic field of view. Therefore, pupil position adjustment, which is adjustment of the direction and position of the pupil, is necessary to prevent the film surface 3 from harmful reflected light from the pupil and to ensure that the objective lens l is at a predetermined distance from the pupil. This must be done using invisible light.

In the embodiment of FIG. 1, pupil alignment is performed using infrared light. Reference numeral 33 denotes a light source for pupil positioning, which is disposed so as to face the pupil of the eyeball E with an infrared transmitting visible light reflecting filter 34 in between. 35 and 36 are reversing mirrors which are placed in the optical path between the objective lens 1 and the relay lens 2 and between the relay lens 2 and the film surface 3 to bypass the relay lens 2 during the pupil alignment operation. Open a light path. 37 is an objective auxiliary lens, 38 is a field lens, and 39 is a transparent chart on which a line diagram as shown in FIG.
Objective M is imaged onto a chart 39 by an auxiliary lens 37 and a field lens 38. Mirrors 42 and 43 bend the optical path of the pupil alignment system. Reference numerals 40 and 41 denote relay lenses that re-image the pupil image formed on the chart 39 onto a symmetrical plane F3 with respect to the reversing mirror 28 disposed in the optical path of the film surface 3.

Light from the pupil of the eyeball E passes through the objective lens l, is reflected by a reversing mirror 35 disposed in the optical path of the photographing system, is directed to an auxiliary objective lens 37, and is imaged on a chart 39. The light from this image is reflected by the mirror 42, passes through the relay lens 40.41, is reflected by the mirror 43 and the reversing mirror 36.28 disposed in the optical path of the imaging system, and is focused on the plane of symmetry F3. Image.

This image is re-formed on the light receiving surface of the image pickup tube 31 by the relay lens 30, so that the image of the pupil is displayed on the monitor television 32. Film plane 3 is used to focus on the fundus mentioned above.
In the embodiment in which the plane of symmetry F3 is moved, the plane of symmetry F3 also moves, and in correlation with this movement, the relay lens 41 moves along the optical axis so that the pupil image is always formed on the plane of symmetry F3. It has become. Therefore, the pupil image displayed on the monitor television 32 is always in focus. The pupil position is aligned by observing the chart 39 and the pupil image displayed on the monitor television 32, and changing the relative position of the camera eyeball E with respect to the pupil in consideration of the position of the pupil image with respect to the line diagram of the chart 39. It is done.

In order to photograph the fundus of a subject using the fundus camera of the embodiment shown in FIG. 1, first, a reversing mirror 35° 36.28 is placed in the optical path of the photographing system, and a light source for pupil positioning is turned on. The pupil position is adjusted while observing the pupil image displayed on the monitor television 32, and then the reversing mirrors 35 and 36 are removed from the optical path, and the partially reflective transparent plate 13 and the reversing mirror 20 are shown in solid lines in FIG. As shown, it is placed in the optical path of the illumination system, illuminates the fundus with infrared light over a wide area, projects a focus index, observes the fundus image and focus index image on a monitor TV, and adjusts the focus while determining the field of view. Reversing mirror 20. ．． 28. The partially reflective transparent plate 13 is removed from the optical path, and the strobe light source 21 is emitted to expose the fundus image onto the photographic film placed on the film surface 3. Although not shown in FIG. 1, lighting of each light source, reversal of each mirror, etc. are performed according to a predetermined interlocking relationship by mechanical or electrical means.

As is clear from the above, according to the fundus camera of the present invention, the position etc. can be adjusted without reducing the pupil light, so there is no need for mydriatics, and the focus adjustment is performed using the focus index image. It is accurate and easy because it can be done while observing, and since it is possible to adjust the focus while observing the fundus imaging range and checking for the presence of ghosts and flares, there are no mistakes in imaging, and it is useful in medical fields such as fundus examinations. It's a big deal.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of one embodiment of the present invention, Fig. 2 is an explanatory diagram of slits, etc. used in the optical system of Fig. 1, and Fig. 3 is an explanatory diagram of an embodiment of the present invention.
FIG. 4, which is a perspective view of a part of the optical system shown in the figure, is an example of a fundus image and a focus index image displayed on a monitor television. In the figure, 1 is an objective lens, 2 is a relay lens, 3 is a film surface, 5 is a focus index light source, 9 is a split image prism, 10 is a focus index, 14 is a relay lens, 15
1 is an optical path dividing means, 16 is an illumination light source, 21 is a stropho light source, 28 is an optical path dividing means, 31 is an image pickup tube, and 32 is a monitor television. Figure 4 Procedural amendment (method) 1. Indication of the case 1982 Patent Application No. 41833 2. Name of the invention Observation device for fundus camera 3. Person making the amendment Relationship to the case Patent applicant class Place Leap 146 Tokyo 3-30-25 Shimomaruko, Ota-ku, Tokyo.
Date of amendment order: June 26, 1980 (shipment date) J. Specification and drawings to be corrected. Contents of the amendment.

Claims (1)

[Scope of Claims] An illumination system that illuminates the subject's eye; an imaging optical system that has an objective lens facing the subject's eye and forms a solid fundus image of the subject's eye at a predetermined position; an observation system for observing a fundus image of the eye to be examined; and an observation system that shares the objective lens and forms a detour optical path by interposing a mirror in the imaging optical system so that the false image of the eye to be examined is coaxial with the fundus image of the eye to be examined. 1. An observation device for a fundus camera, comprising a pupil image forming optical system that forms an ophthalmoscopic pupil image at a position conjugate with the fundus.