JPS61244325A - Eye examination position detector of ophthalmic machine - 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 Field of the Invention The present invention relates to a method for detecting the position of an eye to be examined using an ophthalmological instrument such as a refractometer or a fundus camera.

Conventionally, in order to adjust the distance between the eye to be examined and the ophthalmological instrument, the so-called working distance, this type of device projects an index image toward the eye to be examined and uses the reflected light flux of the index image on the cornea of the eye to be examined. 2. Description of the Related Art An apparatus is known that is configured to form an index image and observe the focus state of this index image to detect the position of the eye to be examined.

However, this device has the disadvantage that detection must be performed while the target image is in focus, making it difficult to easily determine the amount of adjustment of the working distance. Therefore, the light beam reflected from the cornea of the eye to be examined is formed into one image on the imaging plane via two optical paths, and the index image is separated if the working distance is not appropriate, making it easy to determine the position of the eye to be examined. A device for detecting this has been proposed.

However, the above-mentioned device has the disadvantage that the index images are formed by superimposing them, making it difficult to accurately detect the amount of separation when the amount of separation is small. It is something that

This invention for fortune-telling is aimed at solving the problems of the prior art, and involves splitting an index image for working distance detection into two light beams with different polarization components. An image forming optical system having two optical paths for projecting and forming an index image by the reflected light beam of the cornea is characterized by disposing an analyzer that transmits only one polarized component of light in each optical path. It is something.

According to this invention, when the working distance is not appropriate, the target image is separated in a divided state, and even if the amount of separation is small, accurate detection can be performed.

0η FIG. 1 shows a case in which the present invention is applied to a refractometer, in which an objective lens 3 is placed on the optical axis 2 of the cornea IA of the eye 1 to be examined. A diaphragm plate 4 is arranged.

Note that analyzers 5 and 6 are arranged between the objective lens 3 and the aperture plate 4 on both sides with the optical axis 2 in between.

Behind the diaphragm plate 4, convex lenses 8.9 are arranged on both sides of the optical axis 2, that is, in the optical path of each analyzer 5, 6, and behind these convex lenses 8.9, concave lenses 10 are respectively arranged. .11 is located. And these convex lenses 8. Concave lens 10 and convex lens 9. concave lens 11
Two Galileo variable power systems are constructed. Further, a half mirror 12 is arranged on the optical axis 2 and behind the Galileo variable magnification system, and an imaging lens 13 and an imaging tube 14 are arranged behind the half mirror 12. The signal appears on the TV monitor (not shown).
A statue is displayed.

On the other hand, a projection lens 15 is arranged on the reflection optical axis of the half mirror 12 in a direction perpendicular to the optical axis 2, and a light source 17 is placed in front of the projection lens 15 via a reference scale 16.
is arranged to project an image of the reference scale 14 onto the image pickup tube 12.

On the other hand, a polarizing plate 1 is placed in front of the eye 1 to be examined and across the optical axis 2.
8.19 are arranged respectively, and behind each polarized light 18.19, a light source 22.23 is connected via an index plate 20.21.
is located.

As shown in FIGS. 2 to 7, the aperture plate 4 has a vertically elongated through hole 4a in its center, and small circular holes 4a and 4b on both sides of this through hole 4a, respectively. The reference scale 16 has an optical axis index 16a having four short lines arranged around the outer periphery of a small circle, and position fingers 1116b and 16c made of short lines on both sides of the finger 1114a. Further, each index plate 20, 21 (not shown since 21 is the same as 20) has a vertically elongated working distance index 20a, 21a, respectively. Further, each of the polarizing plates 18 and 19 includes polarizing plates 18a, 18b, and 19 that are divided into upper and lower halves, for example.
a, 19b, and each polarizing plate comrades (18a
and 18b, and 19a and 19b), their polarization axes are orthogonal to each other. Note that the polarization axes of the upper and lower polarizers of the two polarizers 18 and 19 are opposite to each other. Both transverse photons 5 and 6 are formed to have different polarization axes and the same polarization axes as the polarization axes of the polarization plates above the polarization plates 18 and 19, respectively.

Note that objective lens 3. The magnification of the imaging optical system composed of the Galileo variable magnification system is set to be higher than that of the imaging optical system composed of the imaging lens 13 and the like.

Further, a half mirror 24 is arranged between the objective lens 3 and the eye 1 to be examined.
A refractometer objective lens 26 and a known refractometer measuring system 27 are arranged in the optical path formed by the refractometer 5.

With these configurations, the reflected light beam from the anterior segment of the subject's eye is made into a parallel light flux by the objective lens 3, passes through the transmission 4a, and then forms an image of the anterior segment of the subject's eye on the imaging tube 14 by the imaging lens 13. As described above, the image of the reference scale 16 is projected onto the image pickup tube 14, and the images of the reference scale and the anterior segment of the subject's eye are superimposed and projected onto the image pickup tube 14.

Further, the light flux from the index plate 20 passes through the polarizing plate 18 and is reflected by the corneal surface of the eye to be examined to form a virtual index image. The light beam is divided into two beams by the small circular holes 4b and 4c.

These two divided light beams are each passed through a convex lens 8. concave lens 10
It passes through two optical paths consisting of a convex lens 9 and a concave lens 11, and forms an index image on an imaging tube 14 by an imaging lens 13.

Here, the above-mentioned analyzer 5 is configured to transmit the light beam that has passed through the upper half of the working distance indicator 20a, that is, the polarizing plate 18a, and to block the light beam that has passed through the lower half of the working distance finger 11120a, that is, the polarizing plate 18b. As a result, the convex lens 8. The light beam transmitted through the optical path formed by the concave lens IO forms an image of the upper half of the working distance index 20a on the image pickup tube 14. Similarly, the analyzer 6 has a working distance index 2
Only the light beam from the lower half of 0a is transmitted, and the light beam that has passed through the optical path consisting of the convex lens 9 and the concave lens 11 forms the lower half of the working distance index 20Fl on the image pickup tube 14.

When the eye to be examined is at an appropriate distance in front of the objective lens 3, each index formed by the light flux passing through both optical paths is located at the image position of the position index 16b projected on the image pickup tube 14.
It is configured to form an index image in which the books overlap, and to form a separate index image in a divided state in the middle with the image position of the position index 16b as the center when the distance is deviated from the appropriate distance.

Note that the light beam from the other working distance finger 111121a is configured to pass through two optical paths and form an index image at the image forming position of the position index 16c on the image pickup tube 14, as described above.

Next, the operation of the optical system constructed as described above will be explained. FIG. 9 shows an image observed on a television monitor when optical axis alignment and working distance alignment adjustment have not been completed.

In this case, the center of the pupil image 1' of the eye to be examined 1 is shifted from the center position of the optical axis index image 16a' of the reference scale 16, and the optical axis alignment is adjusted by moving the entire apparatus upward. . In this case, the working distance is also not appropriate, and the image 208' of the working distance index 20a and the image 218' of the working distance index 21a are observed separately. On the other hand, FIG. 10 shows the AM image on the television monitor at the time when the optical axis alignment adjustment is completed, and shows the center position of the optical axis index image 16a' of the reference scale 14 and the center of the pupil optometry 1' of the eye 1 to be examined. matches. Next, the working distance is adjusted by moving the entire device back and forth so that the working distance index images 20a' and 21a', which are separately viewed on the television monitor, are aligned with the position index images 16b' and 160', respectively.

Next, FIG. 11 shows the observed image on the television monitor when the optical axis alignment adjustment and working distance adjustment are completed, and the center of the pupil image 1a' and the center of the optical axis index image 16a' are aligned. and the working distance indicators 20a' and 21a' both match. By adjusting in this manner, the optical axis alignment working distance adjustment is completed, and the entire apparatus can be accurately positioned with respect to the eye to be examined.

As described above, according to the present invention, when the working distance index image formed by the reflected light beam on the cornea of the eye to be examined deviates from the appropriate distance, it is separated in the middle and is detected. The position of the eye to be examined can be detected extremely easily.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an optical system showing an embodiment of the present invention, Fig. 2 is a plan view showing an example of a diaphragm plate, Fig. 3 is a plan view showing an example of a reference scale, and Fig. 4 is an index. 5 and 6 are plan views showing an example of a polarizing plate, FIGS. 7 and 8 are plan views showing an example of an analyzer plate, and FIG. 9 is a plan view showing an example of an operating path and separation plate. A plan view illustrating a TV monitor image when alignment and optical axis alignment have not been adjusted, FIG. 10 is a plan view illustrating a TV monitor image when working distance alignment has not been adjusted, and FIG. 11 is a plan view illustrating a TV monitor image when alignment and optical axis alignment have not been adjusted. FIG. 3 is a plan view showing a television monitor image when DESCRIPTION OF SYMBOLS 1... Eye to be examined, 3... Objective lens, 5.6... Analyzer, 13... Imaging lens, 18, 19... Polarizing plate. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 1Q Figure 11

Claims (1)

[Claims] (1) An index projection system for projecting an index image for working distance detection toward the cornea of the eye to be examined, and images the index light beam reflected by the cornea of the eye to be examined on one imaging plane through two different optical paths. In the eye position detecting device for an ophthalmological instrument, the target image is divided and projected by two polarized light components having different polarization directions, and one of the imaging optical systems An analyzer is disposed in each of the optical paths that transmits only light of one of the two polarized components, and in the other optical path, transmits only light of the other polarized component. Eye position detection device for ophthalmological instruments.