JPH02161Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an eye refraction measurement device used in objective optometry, and in particular, to an eye refractive power measuring device used for objective optometry. Concerning adjustment means.

(Summary of the invention) The present invention provides an eye refractive power measuring device that uses a third light source for adjustment in order to correctly form images of two light sources, a first and a second light source, on the cornea of the eye through a first optical system. A light source is disposed approximately midway between the two light sources, and a third optical system for forming an image of light from the third light source on the cornea is shared with the first optical system. This makes it possible to simplify the process, reduce costs, reduce light loss, and facilitate adjustment during manufacturing.

(Prior Art) As a method for measuring the refractive power of the eye, subjective optometry has been widely used, in which letters or symbols of varying size are discriminated from a fixed distance.
In recent years, objective eye examination using an eye refraction measuring device has become popular. Although various configurations have been proposed as this eye refraction measuring device, the device shown in FIG. 3 is widely used. That is, the light beams emitted from the two light sources 1 and 2 are turned into parallel beams by the lens 3, and reach the lens 5 through a circular hole 4a formed in a target 4 provided on the optical axis. These two light beams are focused by the lens 5, which is disposed on the same optical axis as the lens 3, and pass through a beam splitter 6 to form images of the two light sources 1 and 2 on the cornea 7a of the eye 7. 1a and 2a are imaged. On the other hand, the image of the circular hole 4a formed in the target 4 passes through the lens 5 and the cornea 7a and forms an image 4b on the retina 7b of the eye 7. The image 4b of the circular hole 4a formed on the thin film 7b is reflected from the retina 7b, and is reflected by the reflective surface 6a formed on the beam splitter 6, and is reflected from the center of the light sources 1 and 2 and approximately between the eye 7 and the center of the light sources 1 and 2. The light is reflected approximately perpendicularly to the optical axis 8 connecting the center, and is further reflected by the reflecting mirror 9 in a direction approximately parallel to the optical axis 8. This reflected light is focused by lens 10, and then further focused by lens 1.
1 becomes a parallel beam of light, which is focused on the detector 13 by the lens 12, and an image 4b formed on the retina of the round hole 4a of the target 4 is imaged on the sensor section of the detector 13. Ru. The target 4 also has a fixation target 15 illuminated by a light source 14.
is fixed to the target 4 at right angles, and the light passing through the fixation target 15 is reflected by the reflecting mirror 16 in the direction of the optical axis 8, and is reflected by the lens 5, the beam splitter 6, and the cornea 7a. An image of the fixation target 15 is formed on the retina 7b through the retina 7b.
At this time, near-infrared light is emitted from the light sources 1 and 2, visible light is emitted from the light source 14 that illuminates the fixation target 15, and the reflector 16 transmits the near-infrared light and makes it visible. Designed to reflect light. Further, the target 4, in which the light source 14, the fixation target 15, and the reflecting mirror 16 are integrally fixed, is configured to be movable by a drive source (not shown).
The lens 11 is also fixed to this target 4. The subject sees the fixation target 15 as a virtual image 15a formed by the reflecting mirror 16, but the position of the virtual image 15a of the fixation target 15 on the optical axis 8 is slightly different from the target 4. When the image 4b of the target 4 is focused on the retina 7b, the image of the fixation target 15 on the retina 7b is out of focus, or is so-called foggy.

When attempting to measure the eye refraction of a subject using the eye refraction measuring device configured as described above,
The subject's eyes are directed toward the image 15a of the fixation target 15 to align the line of sight with the optical axis 8, and the light sources 1 and 2 are alternately flashed to form an image 4 of the target 4 on the retina 7b.
The reflected light b is imaged on the sensor section of the detector 13. At this time, since the fixation target 15 is fogged, no temporary changes such as mechanical myopia occur in the subject's eyes, and measurement can be performed in a natural, unaccommodated state. When the position of the target 4 is set to the focal position of the lens 5, if the eye 7 is emmetropic, the images of the target 4 on the retina 7b from the light sources 1 and 2 will overlap, so the light sources 1 and 2 are alternately set. The position of the image does not move even if it blinks. However, if the eye 7 is myopic or farsighted, the image of the target 4 on the retina 7b is shifted into two. Therefore, the images that the light reflected from the retina 7b forms on the sensor section of the detector 13 through the aforementioned optical system become two circles 4c and 4d whose centers are shifted, as shown in FIG. The sensor section of the detector 13 is composed of upper and lower parts separated by the center line 13a, so when the light sources 1 and 2 are alternately blinked, the amount of received light alternately increases and decreases at the upper and lower parts of the sensor section.
The difference in the amount of received light is converted into an electric signal and transmitted through a control device (not shown) into two images 4c and 4c of the target 4.
The eye refractive power is measured by automatically moving the target 4 to the focal position of the eye 7 where the angles 4d and 4d coincide, and measuring the amount of this movement.

When measuring the eye refraction using the eye refraction measuring device as described above, the central vertex of the cornea 7a of the eye 7 must be correctly on the optical axis 8, and the light source 1, 2 images 1a and 2a must be in focus. Conventionally, as a means for this purpose, as shown in FIG. Reflect at right angle, and then add half mirror 2
0 in the direction of the optical axis 8 and the lens 19
An image 17a of the point light source 17 is formed on the apex at the center of the surface of the cornea 7a, and the reflected light from the cornea 7a of this image 17a is directed approximately at right angles by a reflecting surface 6a formed on the beam splitter 6. The reflected light is reflected by using the reflecting mirror 9 as a half mirror, and the reflected light is transmitted straight, and is focused onto the reflecting mirror 22 by the lens 21, and the focused light is reflected by the reflecting mirror 22 at an approximately right angle. , an image is formed on the imaging tube 23 which senses near-infrared light. The image pickup tube 23
The image 17b of the point light source 17 detected by the point light source 17 can be observed on a monitor television. On the other hand, the light emitted from another visible light source 24 is directed toward the target 25.
Visible light is reflected through a circular hole 25a formed in the target 2 by a reflecting mirror 27 that reflects near-infrared light and near-infrared light is transmitted.
The image 25b of the round hole 25a formed in the image pickup tube 2
3. At this time, the position of the round hole 25a is such that when the image of the point light source 17 is correctly formed on the vertex of the cornea 7a, the image of the point light source 17 is located at the center of the image 25b of the round hole 25a on the imaging tube 23. It is adjusted so that Therefore, the image 17 of this point light source 17
When b is not at the center of the image 25b of the round hole 25a,
The entire measuring device is moved vertically and horizontally with respect to the subject's eye 7, so that the image 17b of the point light source 17 is aligned with the round hole 25.
What is necessary is to adjust it so that it is located at the center of the image 25b of a. Furthermore, when the image of the point light source 17 is blurred, the entire measuring device may be moved back and forth in the direction of the optical axis 8 with respect to the subject's eye 7 to determine the focusing position.

In the conventional eye refractometer configured as described above, the optical system for emitting near-infrared light emitted from the point light source 17 onto the cornea 7a is independent, and the reflecting mirrors 18, 20 and lens 19 are separately provided. However, there were problems in that the mechanism was complicated, the cost increased, and the amount of light was lost.

(Problems to be solved by the invention) The present invention was made in view of the above circumstances, and its purpose is to place the image of the light source for measurement at the correct position on the cornea of the eye using a simple optical system. An object of the present invention is to provide an eye refraction measuring device that can easily form an image.

(Means for Solving the Problems) The present invention aims to direct light from two light sources, a first and a second light source, which are provided close to each other on the optical axis, into the eye of a subject using a first optical system. forming an image on the cornea, and forming an image of a pattern formed by a target separately provided on the optical axis on the retina of the subject's eye by the first optical system; The image of the pattern formed on the retina is focused on a detector by a second optical system, and separately a third light source and third and fourth
In the ocular refractometer, the third light source is provided as an optical system to accurately image the light from the first and second light sources on the cornea. A third optical system is disposed on the optical axis approximately in the middle of the cornea, and is used in common with the first optical system to form an image of the light from the third light source on the cornea.

(Function) With the above configuration, the conventional third optical system is not required, and the image of the third light source is formed on the cornea by the first optical system.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 schematically shows an embodiment of the present invention. In this figure, parts that are the same as or equivalent to those of the conventional example shown in FIG. 3 are designated by the same reference numerals. Since the configuration and operation of the measuring device are almost the same as those of the conventional example, the configuration for focusing and aligning the optical axis of the measuring device with the corneal top of the eye, which is a feature of the present invention, will be explained. A third light source 17 that emits near-infrared light is disposed on the optical axis 8 approximately midway between the first and second light sources 1 and 2 that emit two near-infrared lights for eye refraction measurement. ing.

According to the above configuration, the light emitted from the third light source 17 is transmitted through the lens 3, the target 4, and the lens 5.
The light passes through a first optical system consisting of a beam splitter 6 and a beam splitter 6, reaches the cornea 7a of the eye 7, and forms an image 17a of the third light source 17. This image 17a is the cornea 7a
Similar to the conventional example, the light is reflected from the beam and forms an image on the imaging tube 23, which is sensitive to near-infrared light, via the reflecting surface 6a formed on the beam splitter 6, the half mirror 9, the lens 21, and the reflecting mirror 22. Target 2 at the same time
The image of the round hole 25a formed in the lens 5 is formed on the imaging tube 23 by the light emitted from the light source 24 via the lens 26 and the reflecting mirror 27, as in the conventional example.
An image 17b of the third light source 17 formed on this image pickup tube 23 and an image 25b of the round hole 25a of the target 25
This means that, as shown in FIG. may be moved three-dimensionally with respect to the eye 7. When the measurement button is pressed after the above position adjustment is completed, the third light source 17 is turned off, the first and second light sources 1 and 2 emit light alternately, and measurement is started.

According to the present embodiment described above, unlike the conventional example, the third
The reflector 18, lens 19, and reflector 20 for forming the image of the light source 17 on the cornea 7a of the eye 7 are not required, and the configuration is simplified.

The eye refractive power measuring device described in the above embodiments is not limited to this type, and the present invention can be effectively applied to other types of eye refractive power devices.

(Effect of the invention) As described above, according to the invention, images of the first and second light sources of near-infrared light provided in the eye refractometer are projected onto the cornea of the eye by the first optical system. A third light source for adjustment to correctly form an image through the cornea is disposed on the optical axis approximately midway between the two light sources, and a third light source for focusing the light from the third light source on the cornea. Since the optical system is shared with the first optical system, the structure is simplified and the cost of the device can be reduced, the loss of light quantity is reduced, and adjustment during manufacturing is also facilitated. .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the eye refraction measuring device according to the present invention, FIG. 2 is a front view of a monitor TV screen, and FIG. 3 is a schematic diagram showing a conventional eye refractive power measuring device. FIG. 4 is a front view of the detector shown in FIG. 3. 1...first light source, 2...second light source, 4...
Target, 4a... Round hole, 7... Eye, 7a...
Cornea, 7b... Retina, 8... Optical axis, 13... First
Detector, 17... third light source, 23... second detector.

Claims (1)

[Scope of utility model registration request] a first optical system that images light from two light sources disposed close to each other on the optical axis onto the cornea of the eye of the subject; a target disposed on the optical axis; a second optical system that focuses reflected light of an image of the light pattern formed on the retina of the subject's eye on the first detector; a third light source and a third optical system for correctly forming an image of light on the cornea; In the eye refractometer, the third light source is disposed approximately midway between the two light sources, and the third optical system is connected to the third optical system. An eye refraction measuring device characterized in that it is shared by a first optical system.