JPH0315438A - Alignment device for fundus camera - Google Patents

Abstract

PURPOSE:To contrive the facilitation of confirming alignment adjustment by generating an alignment signal in each light-receiving optical system, in which cornea reflected light rays are respectively guided through a lens to a plurality of optical position detecting sensors for detecting the cornea reflected light rays and displaying an alignment mark together with a fundus image on a television monitor. CONSTITUTION:A quantity of light, projected on photoelectric transfer elements 12a to 12d, is changed by a projection position of coalescence point images S1', S2' on a light receiving element 12, that is, by mutual arrangement of alignment light sources 10, 11 and a detected eye E. Accordingly, being based on ratio of the quantity of light, that is, ratio of an output signal to individual photoelectric transfer elements 12a to 12d, 13a to 13d, a mutual position between a fundus camera and the detected eye E is obtained. Being based on the obtained two mutual positions, two cross-marks M, M are synthetically formed in a fundus image on a monitor television 9 by a video signal generator. The cross-marks M, M are displaced in accordance with the displacement of the mutual position in a surface, vertical with an optical axis L1, with the center of a picture surface of the television monitor 9 serving as the center. Further when the displacement in a direction of the optical axis L1 is left as displayed corresponding to the displacement of the cross-marks M, M, alignment operation is facilitated by a detector while seeing the television monitor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an alignment device for a fundus camera used, for example, in eye 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 angle M reflected light is The deviation is thick〈
, there is a problem that, in some cases, it may come off the finite area of the detector, making it difficult to adjust the alignment. Furthermore,
If the arrangement of the optical system is changed 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.

An object of the present invention is to provide a fundus camera that can easily confirm alignment adjustment by solving the above-mentioned problems of the conventional device and expanding 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.

[Means for Solving the Problems] In order to achieve the above object, the fundus camera alignment device according to the present invention irradiates the entire cornea with a light beam in the fundus camera that displays the fundus image on a television monitor. a plurality of optical position detection sensors that detect the corneal reflected light; a light receiving optical system that guides the corneal reflected light to each of these optical position detection sensors via a lens;
Display means for generating an alignment signal for each of the fluorescence optical systems according to the light position on the light position detection sensor, and displaying an attenment mark on the television monitor together with the fundus image. It is.

[Function] In the retinal camera alignment 1/device having the above-mentioned structure, the angle IIQ reciprocal 4 beams of the light beam projected by the projection optical system are received by the light receiving optical system, and the display means, for example, 2 of the light receiving optical system. The relative position of the eye to be examined and the fundus camera device is determined based on the position where light is received by each element of the photoelectric sensor, and an alignment signal based on this relative position is converted into an image and displayed together with the fundus image on the television monitor. Ru.

[Example] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows the configuration of a fundus camera equipped with an alignment device I according to an embodiment of the present invention.

On the optical axis L1 of the fundus camera, an objective lens l, 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 to be examined. A field lens 6 and an illumination light source 7 are arranged on the bent optical axis L2, and a television camera 8 is arranged on the optical path bent by the flip-up mirror 4, and the output of the television camera 8 is as follows. It is connected to a television monitor 9.

Furthermore, with this fundus camera, as illustrated in Figure 2,
Two alignment light sources 10 located outside the objective lens l
．． 11 are arranged symmetrically with respect to the optical axis Ll, and the light beams emitted by these alignment light sources 10 and 11 are aligned with the cornea Ec.
In order to irradiate the entire area of the cornea and receive the reflected light from the cornea Ec, so-called four-lobed light receiving elements 12 and 13 shown in FIG. 3 are arranged to constitute an alignment device. Each of the light-receiving elements 12 and 13 includes four independent photoelectric conversion elements 12a to 12d, 13a to 13d arranged in the shape of a square.
Along with lenses l4 and 15 for projecting the image on the cornea Ec onto the light receiving elements 12 and 13, they are arranged symmetrically with respect to the optical axis L1 at a position slightly deviated from the optical axis L1 of the fundus camera. .

In the fundus camera alignment device configured in this way, when the alignment light source 10.11 is turned on,
The light beams emitted from these light sources 10 and 11 form two melon point images SL and S2 on the cornea Ec as shown in FIG.
Furthermore, this bright spot image St. The reflected light of S2 is reflected by lenses l4 and l.
5, two bright spot images S1° and S2' are projected onto the light receiving elements 12 and 13. At this time, for example, if the light-receiving element l2 is 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, as shown in FIG. As shown in FIG. 2, the diameters of the bright spot images S1' and S2° expand, and light beams are projected onto the plurality of photoelectric conversion elements 12a to 12d. Here, photoelectric conversion elements 12a to 12
The amount of light projected on d is determined by the projection position of the bright spot image St', S2° onto the light receiving element l2, that is, the alignment light source 10,
1l and the subject's eye E, the individual photoelectric conversion elements 12a to 12d. Based on the light amount ratio, that is, the ratio of the output signals to 13a to 13d, the relative position between the fundus camera and the eye E to be examined is determined.

Based on the two mutual positions obtained in this way,
Two cross marks M, M as shown in FIG. 5 are synthesized and displayed on the fundus image on the television monitor 9 by a video signal generator (not shown). 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 the deviation in the optical axis L1 direction is If the cross marks M, M are displayed in correspondence with the deviation of the cross marks M, it becomes easy for the examiner to perform alignment operations while looking at the television monitor 9.

FIG. 6 is an anatomical 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, there is a A light splitting material 21 is inserted which has a characteristic of transmitting light of a wavelength used for imaging and reflecting light of other wavelengths. On the other hand, one alignment light source 22 is arranged on the optical axis L3 bent by the light splitting member 21, and furthermore, at a position slightly deviated from this optical axis L3, there is a light source similar to the first embodiment. Two four-lobed light receiving elements 23 and 24 are arranged symmetrically with respect to the optical axis L3. Furthermore, lenses 25 and 26 are provided on the optical axes of the light receiving elements 23 and 24 to guide corneal reflected light.

In this second embodiment, only one alignment light source 22 is used, but this light source 22 is used to emit corneal Ec.
The light beam that irradiates the entire area of the cornea and is reflected by the cornea Ec passes through the objective lens 1 again and then is reflected by the light splitting member 21, and then passes through the lenses 25 and 26 as in the previous embodiment.
Due to this action, a bright spot image S3 is projected onto the light receiving elements 23 and 24 as shown in FIG. Even in this case, the projected bright spot image S3 changes depending on the mutual arrangement of the eye E and the fundus camera, so the same processing as in the previous embodiment may be performed.

Note that an array sensor such as a COD may be used as the optical position detection sensor used in the present invention.

[Effects of the Invention] As explained above, the fundus camera alignment device according to the present invention irradiates the entire cornea with a light beam, and the reflected light beam from the cornea is spread, so even if the eye to be examined is slightly shifted, the reflected light is not reflected. It can receive light and achieve three-dimensional alignment efficiently.

[Brief explanation of drawings]

The drawings show an embodiment of the alignment device for a fundus camera 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, Fig. 5 is an explanatory diagram of an image on a TV monitor, Fig. 6 is a schematic diagram of the $2 embodiment, and Fig. 7 is a light reception diagram. FIG. 3 is an explanatory diagram of a bright spot image of an element. Symbol l is an objective lens, 2 is a perforated mirror, 4 is a flip-up mirror, 5 is a photographic film, 7 is an illumination light source, 8 is a television camera, 9 is a television monitor, 10, 1l, 22 are alignment light sources, 12, 13 , 23, 24 are light receiving elements, 21
is a photopartite dissecting material.

Claims (1)

[Claims] 1. A fundus camera that displays a fundus image on a television monitor includes an irradiation optical system that irradiates the entire cornea with a beam of light, multiple optical position detection sensors that detect corneal reflected light, and a lens for these optical position detection sensors. A light-receiving optical system guides corneal reflected light through the light-receiving optical system, and an alignment signal is generated for each light-receiving optical system based on the light position on the light position detection sensor, and an alignment mark is displayed on the television monitor together with the fundus image. 1. An alignment device for a fundus camera, comprising: display means for displaying information.