JPH0567281B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an alignment device for ophthalmological equipment used, for example, in ophthalmological clinics.

[Prior art] When photographing the fundus of an eye to be examined using a fundus camera, the optical axis of the optical system of the fundus camera and the visual axis of the eye to be examined are aligned, and the working distance between the two is matched to an optimal value. Correct operation is an essential condition for achieving accurate and highly accurate inspection. A method for performing this adjustment is to project an alignment index onto the cornea of the eye to be examined, observe the arrival position of the light reflected by the cornea of this index, and detect the relative position between the eye to be examined and the fundus camera. has been proposed in the past. In such conventional methods, the corneal reflected light is generally transmitted through the photographing lens system of the fundus camera and then onto the optical position detector placed on the corneal conjugate plane close to the fundus image formation plane on the optical axis of the fundus camera. It is forming an image.

[Problems to be Solved by the Invention] However, with the general fundus camera as described above, even if the subject's eye deviates slightly from the predetermined position, the light beam is projected near the cornea, so the corneal reflected light may be polarized. There is a problem in that the position is large, and in some cases it may deviate from the finite area of the detector, making alignment adjustment difficult. Furthermore, if the arrangement of the optical system is changed in order to increase the magnification of the fundus camera, there is a disadvantage that the positional range of the eye to be examined over which reflected light is detected becomes even narrower.

The purpose of the present invention is to solve the above-mentioned problems of the conventional device and expand the position range of the eye to be examined for detecting the corneal reflected light of the alignment index.
An object of the present invention is to provide an alignment device for ophthalmic equipment that can easily confirm alignment adjustment.

[Means for Solving the Problems] In order to achieve the above object, an alignment device for an ophthalmological device according to the present invention includes the following steps: , an irradiation optical system that irradiates the cornea of the eye to be examined with a luminous flux, a light position detection sensor that detects corneal reflected light from two directions, and a light receiving optical system that guides the corneal reflected light to the light position detection sensor through a lens. system and the optical position on the optical position detection sensor to generate an alignment signal, and based on the alignment signal, information in a direction perpendicular to the optical axis of the eye to be examined is expressed as a position, and information in the optical axis direction is expressed as a shape. and a display means for displaying a mark on the television monitor together with an image of a predetermined part of the eye to be examined.

[Operation] In the ophthalmological equipment alignment device having the above configuration, the corneal reflected light of the light beam projected by the projection optical system is received by the light receiving optical system, and the display means displays the light reflected from the cornea of the light beam projected by the projection optical system, for example, two photoelectric sensors of the light receiving optical system. The relative position of the eye to be examined and the fundus camera device is determined from the position of light received by each element, and an alignment signal based on this relative position is converted into an image and displayed together with the fundus image on a television monitor.

[Example] The present invention will be described in detail based on the illustrated example.

FIG. 1 shows the configuration of a fundus camera equipped with an alignment device according to an embodiment of the present invention.
On the optical axis L1 of the fundus camera, an objective lens 1, a perforated mirror 2, an imaging lens 3, a flip-up mirror 4, and a photographic film 5 are arranged in order from the side closest to the eye E. A field lens 6 and an illumination light source 7 are arranged on the optical axis L2 bent by the flip-up mirror 4, and a television camera 8 is arranged on the optical path bent by the flip-up mirror 4.
The output of the television camera 8 is connected to a television monitor 9.

Furthermore, in this fundus camera, as illustrated in FIG. 2, two alignment light sources 10 and 11 are arranged symmetrically with respect to the optical axis L1 outside the objective lens 1. The emitted light beam irradiates the entire area of the cornea Ec, and so-called four-lobed light receiving elements 12 and 13 shown in FIG. 3 are arranged to receive the reflected light from the cornea Ec, thereby forming an alignment device. The light-receiving elements 12 and 13 are each composed of four independent photoelectric conversion elements 12a to 12d, 1 arranged in a ``field'' shape.
3a to 13d, a lens 14 for projecting the image on the cornea Ec onto the light receiving elements 12, 13;
15, it is arranged symmetrically with respect to the optical axis L1 at a position slightly deviated from the optical axis L1 of the fundus camera.

When the alignment light sources 10 and 11 are made to emit light in the alignment device for ophthalmic equipment configured in this manner, the light beams emitted from these light sources 10 and 11 form two bright spots on the cornea Ec as shown in FIG. Images S1 and S2 are formed, and further these bright spot images S1 and S
2 reflected light forms two bright spot images S1' and S on the light receiving elements 12 and 13 by the action of the lenses 14 and 15.
Project 2'. At this time, for example, the light receiving element 12
If the alignment light sources 10 and 11 are placed slightly shifted in the optical axis direction from the conjugate position of the alignment light sources 10 and 11 with respect to the lens 14 and the cornea Ec, the bright spot images S1' and S2' will be slightly blurred and become bright spot images as shown in FIG. S1',S
The diameter of 2' is expanded, and a plurality of photoelectric conversion elements 12a
The light beam will be projected onto ~12d. Here, the amount of light projected onto the photoelectric conversion elements 12a to 12d depends on the projection position of the bright spot images S1', S2' onto the light receiving element 12, that is, the mutual arrangement of the alignment light sources 10, 11 and the eye E to be examined. Therefore, the mutual position of the fundus camera and the eye E to be examined is determined based on the light amount ratio, that is, the ratio of the output signals to the individual photoelectric conversion elements 12a to 12d and 13a to 13d.

Based on the two mutual positions obtained in this way, a video signal generator (not shown) generates a fifth signal.
Two cross marks M, M as shown in the figure are combined and displayed on the fundus image on the television monitor 9. For example, the cross marks M, M are deviated from the center of the screen of the television monitor 9 in accordance with the mutual positional deviation in a plane perpendicular to the optical axis L1, and further
If the deviation in direction is displayed in correspondence with the deviation of the two cross marks M, M, it becomes easy for the examiner to perform alignment operations while looking at the television monitor 9.

FIG. 6 is a partial configuration diagram showing the second embodiment. Between the objective lens 1 and the perforated mirror 2, which constitute the optical system of the fundus camera similar to the previous embodiment,
A light splitting member 21 is inserted which has a characteristic of transmitting light of a wavelength used for imaging during fundus observation and reflecting light of other wavelengths. On the other hand, one alignment light source 22 has an optical axis L bent by the light splitting member 21.
3, and furthermore, at a position slightly off from the optical axis L3, there is a 2 similar to that in the first embodiment.
The four-lobed light receiving elements 23 and 24 are arranged symmetrically with respect to the optical axis L3. In addition, the light receiving element 2
On the optical axis of lenses 3 and 24, there is a lens 2 that guides corneal reflected light.
5 and 26 are provided.

In this second embodiment, alignment light source 22
Although only one light source 22 is used, the light beam emitted from this light source 22 irradiates the entire cornea Ec and is reflected by the cornea Ec. After passing through the objective lens 1 again, it is reflected by the light splitting member 21. As in the case of the previous embodiment, due to the action of lenses 25 and 26,
As shown in FIG. 7, the bright spot image S3 is
24. Even in this case, since the projected bright spot image S3 changes depending on the mutual arrangement of the eye E and the fundus camera, the same processing as in the previous embodiment may be performed.

Note that the optical position detection sensor used in the present invention is
An array sensor such as a CCD may also be used.

[Effects of the Invention] As explained above, the alignment device for ophthalmic equipment according to the present invention irradiates the entire cornea with a light beam, and the reflected light beam from the cornea is spread out, so even if the subject's eye is slightly shifted, the reflected light does not change. can receive light, and three-dimensional alignment can be achieved efficiently.

[Brief explanation of the drawing]

The drawings show an embodiment of the alignment device for ophthalmological equipment according to the present invention, FIG. 1 is a configuration diagram of the first embodiment, FIG. 2 is a layout diagram of a light source and a light receiving element, and FIG. 3 is a diagram showing the arrangement of a light source and a light receiving element. An explanatory diagram of a bright spot image, Fig. 4 is a front view of the cornea, and Fig. 5 is an explanatory diagram of an image on a television monitor.
FIG. 6 is a block diagram of a main part of the second embodiment, and FIG. 7 is an explanatory diagram of a bright spot image of a light receiving element. Code: 1 is objective lens, 2 is mirror with hole, 4
is a flip-up mirror, 5 is a photographic film, 7 is a lighting source, 8 is a television camera, 9 is a television monitor, 1
0, 11, 22 are alignment light sources, 12, 1
3, 23, and 24 are light receiving elements, and 21 is a light splitting member.

Claims (1)

[Claims] 1 In an alignment device for ophthalmological equipment that displays an image of a predetermined part of the eye to be examined on a television monitor, an irradiation optical system that irradiates the cornea of the eye to be examined with a beam of light, and a light position detection sensor that detects corneal reflected light from two directions. , a light-receiving optical system that guides the corneal reflected light to the optical position detection sensor through a lens, and generates an alignment signal based on the optical position on the optical position detection sensor, and adjusts the light of the subject's eye based on the alignment signal. The apparatus is characterized by comprising display means for displaying an alignment mark representing information in a direction perpendicular to the axis by position and information in the direction of the optical axis by shape on the television monitor together with an image of a predetermined part of the eye to be examined. Alignment device for ophthalmological equipment.