JPH1170076A - Optometry device - Google Patents

Abstract

(57) [Summary] [Problem] To prevent the apparent size of an optotype having a fixed position from changing even when diopter is changed. SOLUTION: A light beam from a target 6 is converted into a parallel light beam by a collimator lens 5 and formed as a target image 6 'by a diopter variable lens 2. The size of the optotype image 6 'is constant irrespective of the position of the diopter variable lens 2, and the pupil of the eye E to be examined is at the front focal position of the objective lens 1, so that the apparent size of the optotype image 6' That is, the viewing angle is also kept constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optometry apparatus used in hospital ophthalmology, optician stores, and the like.

[0002]

2. Description of the Related Art Conventionally, in a variable diopter optical system, which is often used in an auto-refractometer, a subjective refractometer, a visual acuity meter, etc., the size of an apparent diopter changes with diopter. The target is moved in the direction of the optical axis to change the target. In a target optical system in which the target is fixed, the lens is moved in the optical axis direction.

[0003]

However, even in the above-described conventional optotype optical system in which the diopter is changed by moving the lens in which the position of the optotype is fixed in the optical axis direction, the image formation position by the lens is changed. A problem arises in that the apparent size of the target slightly changes.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide an optometric apparatus in which the apparent size of an optotype does not change even when the diopter is changed by an optotype optical system having a fixed optotype position.

[0005]

An optometry apparatus according to the present invention for achieving the above object comprises an objective lens or an objective optical system having an anterior segment of an eye to be examined as a front focal position, and a luminous flux from a target. And a diopter variable lens movable in the optical axis direction in the parallel light by the collimator lens behind the objective lens.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 shows a configuration diagram of the optotype optical system of the first embodiment. The anterior segment of the eye E is at the front focal position of the objective lens 1. On an optical path O1 passing through the center of the objective lens 1, a diopter variable lens 2, a cylindrical concave lens 3, a cylindrical convex lens 4, and a collimator lens 5 are sequentially arranged. At the rear focal position of the collimator lens 5, an optotype disk 7 having various optotypes 6 is arranged, and the optotype disk 7 can be rotated by a stepping motor 8.

Further, the diopter variable lens 2 is driven by the driving means 2a on the optical path O1 as shown by an arrow so that the presented diopter of the target 6 can be changed. Further, the cylindrical concave lens 3 and the cylindrical convex lens 4 have the same absolute value of the refractive power, and are rotated around the optical path O1 by the driving means 3a and 4a, respectively.
The astigmatism of the eye E is corrected.

With the above configuration, the stepping motor 8
Is driven to rotate the target disc 7 to change the diopter of the target 6 and present it to the eye E to be examined. The luminous flux from the optotype 6 is converted into a parallel luminous flux by the collimator lens 5, and the parallel luminous flux passes through the cylindrical convex lens 4 and the cylindrical concave lens 3, forms a target image 6 ′ by the diopter variable lens 2, and the eye E to be inspected is an objective. The optometry is performed while viewing the optotype image 6 ′ through the lens 1.

The size of the target image 6 ′ is determined by the diopter variable lens 2.
And the pupil of the eye E is at the front focal position of the objective lens 1, so that the apparent size of the target image 6 ', that is, the viewing angle is also kept constant. Further, the cylindrical concave lens 3 and the cylindrical convex lens 4 are respectively driven by driving means 3a, 4
By rotating at a, the astigmatism of the eye E is corrected. Note that the two cylindrical lenses 3 and 4 may be cylindrical lenses having the same reference number, but in that case, collimator lenses including the cylindrical lenses are used.

FIG. 2 is a diagram showing the configuration of a target optical system according to a second embodiment. In the optical path O1 of the objective lens 11 facing the anterior segment of the eye E to be examined, the anterior segment of the objective lens 11 is conjugated. Cylindrical lenses 12, 13, lens 14,
A diopter variable lens 15, a collimator lens 16, and a target 17 which is a liquid crystal image display panel are sequentially arranged. Here, the optical system including the objective lens 11 and the lens 14 is
A cylindrical lens 1 corresponds to the objective lens 1 of the first embodiment.
Numerals 2 and 13 denote cylindrical convex lenses having the same refractive power, which are rotated around the center of the optical path O1 by driving means 12a and 13a, respectively. The diopter variable lens 15 is connected to a driving unit 15a.

With the above configuration, the objective lens 11 forms an image of the anterior segment of the eye E at the front focal position of the lens 14 once. On the liquid crystal image display panel, various patterns of optotypes 17 are displayed by a computer. I do. The eye E examines the target image 17 ′ through the objective lens 11, the cylindrical convex lenses 12, 13, and the lens 14.

The diopter variable lens 15 is driven by the driving means 15a in the direction of the optical path O1 to change the diopter diopter. However, even if the diopter changes, the apparent size of the diopter 17 'does not change. By providing the pupil conjugate position in the middle between the objective lens 11 and the lens 14, the working distance can be increased and the movable amount of the diopter variable lens 15 can be reduced.

[0013]

As described above, in the optometry apparatus according to the present invention, the diopter variable lens is movable in the optical axis direction within the parallel light beam by the objective lens or the collimator lens behind the objective optical system, and the visual target is viewed. Since the degree is changed, the apparent size of the target due to the change in diopter can be prevented from changing even with the target fixed in the optical axis direction.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram of a second embodiment.

[Explanation of symbols]

 1,11 Objective lens 2,15 Diopter variable lens 3,4,12,13 Cylindrical lens 5,16 Collimator lens 6,17 Optotype 7 Optotype disc 8 Stepping motor

Claims (2)

[Claims] 1. An objective lens or an objective optical system having an anterior eye portion of an eye to be examined as a front focal position thereof, a collimator lens for converting a light beam from a target into parallel light, and the collimator lens behind the objective lens. An optometry apparatus comprising: a diopter variable lens movable in an optical axis direction in parallel light. 2. The optometry apparatus according to claim 1, wherein the objective optical system includes a pair of convex lenses, and an anterior segment conjugate position is provided therebetween.