JPH04343036A - Optical refraction measuring device - 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]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical refraction measuring device used in eye clinics and eyeglass stores.

0002

2. Description of the Related Art Conventionally, there has been known a refraction measuring apparatus for an optical system under test, which measures the refractive index by receiving transmitted light emitted from a plurality of locations of a measurement aperture using an area sensor array.

0003

[Problems to be Solved by the Invention] However, in the conventional example described above, only the barycentric coordinates of the light beam are detected, so if the optical system to be tested is a bifocal lens, the power of each lens must be measured separately. It cannot be measured.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical system refraction measuring device that can individually measure each power of a bifocal lens of a diffractive optical system to be tested.

[0005]

[Means for Solving the Problems] An optical system refraction measuring device according to the present invention for achieving the above-mentioned object uses an imaging element to capture a light beam passing through a test optical system passing through a plurality of apertures around the optical axis. It has a light-receiving system that receives light, and measures the bifocal degree of the optical system to be tested based on the shape difference between the radiation direction and the circumferential direction with respect to the optical axis of the light beam image received on the image sensor. It is something to do.

[0006]

[Operation] The optical system refraction measurement device having the above-mentioned configuration uses a photographic element to receive transmitted light from a test optical system having a double focus emitted from multiple locations around the measurement aperture, and the center of gravity of the light flux from each location. Find each focal length based on the coordinates and shape.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail based on the illustrated embodiments. FIG. 1 shows a configuration diagram of an embodiment, in which a lens 2, a test lens 3, an abutment member 4, and apertures 5a to 5d shown in FIG. A four-hole diaphragm 5 having a diaphragm 5 and an image sensor 7 of a television camera 6 are arranged. The lens 3 to be tested is brought into contact with the contact member 4,
It is fixed along the optical axis. The output of the image sensor 7 is connected to a signal processor 8 and a monitor 9. Additionally, there is an additional power button 1 that displays the difference between the near vision position and the far vision position of the progressive lens.
The output of 0 is connected to the signal processor 8.

Prior to measurement, alignment is performed, and a measurement button (not shown) is pressed to turn on the point light source 1. Point light source 1
The light flux becomes parallel light at the lens 2, passes through the test lens 3 and the aperture 5, and is received by the image pickup device 7. The output of the image pickup device 7 is input as a video signal from the television camera 6 to a signal processor 8, and the signal processor 8 calculates the coordinates of the light flux to obtain the refraction value of the lens 3 to be tested.

FIGS. 3(a) and 3(b) show the light flux images on the image sensor 7, and the four light flux images Ma to Md are the light flux images on the test lens 3.
If the refractive degrees of the light beams differ, the light beams move in the radial direction with respect to the optical axis O1 on the image sensor 7 as shown in (a). Note that the addition power of the lens is usually 2 to 3 diopters, and with this level, the beam spot will not be separated even if a slight deviation occurs, as shown in (a).

When the test lens 3 is a diffractive bifocal lens, the beam images Ma to Md are divided into two parts, but they are not separated on the test element 7, as shown in FIG. 3(b). becomes an ellipse. The coordinates of the center of gravity of this ellipse are the average value of the two focal points. Further, the difference (d2-d1) between the circumferential direction dimension d1 and the radial direction dimension d2 represents the difference between the first focal point and the second focal point. Since this detection of the shape takes more calculation time than the calculation of the center of gravity, it may be performed only when the addition button 10 is pressed, for example. In the signal processor 8, the addition button 10 is pressed next to the measurement button.
It is preferable that the shape detection program is activated when is pressed and the center position coordinates do not change.

In this embodiment, since the point light source 1 and the aperture of the aperture 5 are circular, the light flux images Ma to Md on the image sensor 7 are
is also a yen. Further, when a bifocal lens is inserted, it becomes an ellipse, so it can be determined from this ellipticity that the lens 3 to be tested is a bifocal lens, but the aperture shape does not need to be circular. However, if it is a circle, it can be determined from the ellipticity that it is a bifocal lens, which has the advantage of making it easier to recognize the shape.

FIG. 4 is a block diagram of an embodiment in which the present invention is applied to a refractometer for measuring the ocular refraction value of an eye to be examined equipped with an intraocular lens. On the optical axis O2 extending from the point light source 11 to the fundus R of the eye E to be examined, a lens 12, an aperture 13 having a central aperture 13a shown in FIG. An intraocular lens 16 has been inserted. Moreover, on the optical axis O3 in the reflection direction of the perforated mirror 14,
A six-hole diaphragm 17 having six apertures 17a to 17f shown in FIG. 6, a lens 18, and six wedge prisms 19a shown in FIG.
A prism 19 having ~19f and a television camera 6
An image sensor 7 is arranged. The output of the image sensor 7 is connected to a signal processor 20, and the output of the signal processor 20 is connected to a light source 11.

A spot-like light flux is emitted from the light source 11, and this light flux passes through the lens 12, the central aperture diaphragm 13, the perforated mirror 14, the objective lens 15, and the intraocular lens 16, and enters the fundus R of the eye E to be examined. . The reflected light from the fundus R returns along the same optical path again, passes through the intraocular lens 16 and the objective lens 15, is reflected by the perforated mirror 14, and is separated from the optical axis O3 by the 6-hole diaphragm 17, lens 18, and prism 19. It reaches the image sensor 7, and six light beam images Ma to M are formed on the image sensor 7.
It is projected as f.

The barycentric coordinates of these beam images are determined by the signal processor 2.
Calculate with 0 to find the refraction value including astigmatism. When the eye E to be examined has a diffractive intraocular lens 16 inserted, as shown in FIG. If you look into it, you can find the difference in bifocals.

In this embodiment, light is emitted from the center of the pupil,
Luminous flux is emitted from 6 places around the pupil, but conversely, 6 spot lights are irradiated to the fundus R from 6 places around the pupil.
The light may be taken out from the center of the pupil, and six spot images may be received by an image sensor at a location conjugate with the fundus R.

[0016]

As explained above, the optical system refraction measuring device according to the present invention can determine the focal length or refractive power of each lens, even if the lens to be tested is a diffractive bifocal lens.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a front view of a four-hole diaphragm.

FIG. 3 is an explanatory diagram of a light flux on an image sensor.

FIG. 4 is a configuration diagram of a second embodiment.

FIG. 5 is a front view of the central aperture stop.

FIG. 6 is a front view of a 6-hole diaphragm.

FIG. 7 is a front view of the prism.

FIG. 8 is an explanatory diagram of a light flux on an image sensor.

[Explanation of symbols]

1, 11 Light source 3 Test lens 5 4-hole aperture 6 TV camera 7 Imaging device 8, 20 Signal processor 9. Monitor 10 Addition button 13 Center aperture diaphragm 14 Hole mirror 16 Intraocular lens 17 6-hole aperture 19 Prism

Claims (1)

[Claims] 1. A light-receiving system that receives a light beam passing through a test optical system passing through a plurality of apertures around the optical axis with an image sensor, and a radiation direction of a light beam image received on the image sensor with respect to the optical axis. 1. An optical system refraction measuring device, characterized in that the bifocal degree of the optical system to be tested is measured based on the difference in shape between the optical system and the circumferential direction.