JP2002330929A - Optotype presenting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optotype presenting device capable of performing an exact optometry by presenting the image of a target always at a fixed distance to an eye to be tested without regard to an optometric space. SOLUTION: A concave lens 10 is inserted into a target optical system 6 corresponding to the change of a distance to a device body 1 from the eye to be tested E to form a target image at a fixed distance. Thus, the target image of a fixed dimension can be presented to the eye without regard to the distance between the eye E of a patient and the device main body 1 and the exact optometry with respect to the eye E is carried out without regard to the optometric space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a visual acuity chart presenting apparatus, and more particularly, to a visual acuity chart presenting apparatus for presenting an image of a target to an eye to be examined using a half mirror and a concave mirror.

[0002]

2. Description of the Related Art Conventionally, a visual acuity chart presenting apparatus using a half mirror and a concave mirror has a fixed distance system in which an image of an optotype for an optometry is always presented at a fixed distance, and a visual acuity table for an optometry. There is an infinity type in which a target image is formed at infinity and presented to the subject's eye.

[0003]

However, in the case of the conventional fixed distance type visual acuity table presenting apparatus described above, since this visual acuity table presenting apparatus is fixed at a predetermined place, when the optometry space is narrow, There has been a problem that the subject cannot look into the target at a fixed position and cannot perform an accurate optometry.

In a conventional infinity-type visual acuity chart presenting apparatus, a parallel light beam is incident on an eye to be inspected from a visual target.
Normally, since the eyesight test of the eye to be examined is performed at an eye examination distance of 5 m, a difference in accommodation power of the eye to be examined occurs, resulting in overcorrection, a difference from an eyesight value measured by another optometry apparatus, and the like. There has been a problem that an accurate optometry cannot be performed.

The present invention has been made in view of the above circumstances, and is capable of presenting an image of a target at a fixed distance to an eye to be inspected regardless of the size of an eye examination space, and performing an accurate eye examination. It is an object to provide a presentation device.

[0006]

According to the first aspect of the present invention,
A visual acuity table presentation device including a visual target optical system using a concave mirror and a semi-transparent mirror for forming a visual target image of a visual target attached to a visual acuity chart at a predetermined distance from an eye to be examined, in the apparatus main body, As a target optical system, an auxiliary optical member is used for forming the optotype image at a constant distance in accordance with a change in the distance of the subject's eye to the apparatus main body.

[0007]

Embodiments of the present invention will be described below in detail.

(Embodiment 1) FIGS. 1 to 5 show a visual acuity chart presenting apparatus according to a first embodiment of the present invention. FIG. 1 is a perspective view of the visual acuity chart presenting apparatus according to the first embodiment. FIG. 2 is a cross-sectional view of the visual acuity table presenting device of the first embodiment, FIG. 3 is a cross-sectional view of the visual acuity table presenting device of the first embodiment, and FIG. FIG. 5 is a partial cross-sectional view illustrating the groove frame portion 9, and FIG. 5 is a cross-sectional view illustrating a use state of the visual acuity table presentation device according to the first embodiment.

The visual acuity table presentation device of the first embodiment shown in FIGS. 1 to 3 is a rectangular parallelepiped device main body 1 provided with a rectangular opening 2 for viewing at one end surface, and the device main body 1. An optotype plate 4 provided with an optotype 5 such as a Landolt's ring, and an image of the optotype 5 at a position where the subject's eye E of a subject sitting toward the apparatus main body 1 can view it. That is, a target optical system 6 that forms an image at a position where the eye to be inspected can be visually recognized by looking through the opening 2 is provided.

As shown in FIGS. 1 to 3, the optotype optical system 6 is arranged at a half angle of 45 degrees with respect to the optical axis of the optotype plate 4 through which the light beam from the optotype 5 passes. A half mirror 7 which is a transparent mirror, and a concave lens 10 as an auxiliary optical member which is inserted into and removed from the optical axis between the target plate 4 and the half mirror 7
And a concave mirror 8 for reflecting the light beam transmitted through the half mirror 7. The light beam from the concave mirror 8 is
Is reflected toward the subject's eye E through the target, thereby forming an optotype image of the optotype 5 on the optotype plate 4 as a virtual image 5a at a distance of 5 m from the eye E, for example.

As shown in FIGS. 2 and 3, the concave mirror 8 is positionally adjustable in the direction of the optical axis L with respect to the optical axis L formed by the target plate 4 and the half mirror 7. That is, as shown in FIG. 4, a lid 9 which is detachable from the apparatus main body 1 is provided on an end surface of the apparatus main body 1 on the side of the concave mirror 8. The cover frame 9 is provided with a grooved frame 11 provided with two, for example, substantially semicircular grooves 11a and 11b in a direction orthogonal to the direction of the axis L.
With the concave mirror 8 in the groove 1
It can be replaced with either one of 1a and 11b.

FIG. 2 shows a state in which the lid 9 with the concave mirror 8 inserted in the groove 11a is attached to the apparatus main body 1, and FIG. 3 shows a state in which the concave mirror 8 is inserted in the groove 11b. 9 shows a state in which 9 is attached to the apparatus main body 1.

In the arrangement of the concave mirror 8 shown in FIG.
The distance of the eye E to the visual acuity table presentation device is 1.1 m
In this state, when the virtual image 5a forms an image at a distance of 5 m from the eye E to be inspected, and the concave mirror 8 is arranged as shown in FIG. When the distance of the eye E to the table presentation device is 0.7 m, the virtual image 5a is formed at a position 5 m away from the eye E.

According to the visual acuity chart presenting apparatus of the first embodiment, a simple operation of inserting the concave lens 10 into or out of the optical axis L while inserting the concave lens 10 into one of the grooves 11a and 11b of the concave mirror 8, Regardless of the distance of the eye E to the apparatus main body 1, the optotype optical system 6 can form a target image of the target 5 as a virtual image 5 a at a distance of 5 m from the eye E, for example. As a result, as shown in the upper part of FIG. 5, optometry is performed with the distance between the apparatus main body 1 and the subject's eye E being 1.1 m so that the lens storage drawer 13 containing a large number of optometry lenses of the optometry table 12 can be pulled out. In the case (corresponding to the state shown in FIG. 2) or the space for the optometry, the apparatus main body 1 is brought closer to the optometry table 12 without using the lens storage drawer 13, and the distance between the apparatus main body 1 and the eye E to be examined is reduced. 0.7 It can cope with any case where the eye examination (may correspond to the state shown in FIG. 3) as a.

(Embodiment 2) Next, a visual acuity table presentation apparatus according to Embodiment 2 will be described with reference to FIGS.

FIG. 6 is a front view of the visual acuity chart presenting apparatus of the second embodiment, FIG. 7 is a cross-sectional view of the visual acuity chart presenting apparatus of the second embodiment,
8 is a cross-sectional view when the position of the concave mirror in the visual acuity table presentation device of the second embodiment is changed and an auxiliary optical member is used, FIG. 9 is a schematic front view of a visual acuity surface plate used in the second embodiment, FIG. 10 is a schematic sectional view showing a receiving frame for changing the position of the concave mirror in the second embodiment, and FIG. 11 is a schematic sectional view showing a receiving frame and a spacer for changing the position of the concave mirror in the second embodiment.

The visual acuity chart presenting apparatus according to the second embodiment has a variety of optometrists including the optotypes 5 arranged in a circular arrangement in the apparatus main body 20 so that light can be transmitted therethrough. 3
0, and the rotating plate 21
And an optotype that forms an optotype image of each optotype including the optotype 5 on the rotating plate 21 at a position at a distance of 5 m from the eye E to be examined. And an optical system 23.

The illumination system 22 includes a light source lamp 25, a reflecting mirror 26, a condenser lens system 27, and a filter 28. The light from the light source lamp 25 is reflected by the reflecting mirror 26, and the condenser lens system. 27, each target including the target 5 of the rotating plate 21 is illuminated via the filter 28.

The target optical system 23 includes a reflection mirror 35.
And a half mirror 7 and a concave mirror 8 whose position can be adjusted in the direction of the optical axis L1. The light flux from each target illuminated by the illumination system 22 is reflected by a reflection mirror 35, and the half mirror 7, By projecting toward the eye E by the action of the concave mirror 8, images of various optotypes including the optotype 5 are formed as virtual images at a distance of 5 m from the eye E, for example.

The optical path of the optotype optical system 23 further includes:
As shown in FIG. 8, a concave lens 31 as an auxiliary optical member
Are arranged so that they can be inserted and removed.

The concave lens 31 can be inserted into and removed from the optical path of the optotype optical system 23, for example, by providing the openable and closable lid 20a on the wall plate of the apparatus body 20, as shown in FIG. Is opened, and the concave lens 31 is inserted into or removed from the optical path near the rotating plate 21.

Then, by the target optical system 23, FIG.
As shown in FIG. 1, the distance between the eye E and the apparatus body 20 is 1.
1 m and the distance between the subject's eye E and the virtual image of the optotype is 5 m, and the insertion of the concave lens 31 into the optotype optical system 23 and the position adjustment of the concave mirror 8 are performed. The distance between the subject's eye E and the apparatus body 20 shown in FIG.
The distance between the subject's eye E and the virtual image of the optotype is 5 m.

Reference numeral 20b denotes an opening for the eye E provided in the apparatus main body 20.

As shown in FIG. 9, in addition to the Landolt ring optotype group 42 including the optotype 5, the rotating plate 21 has a Hiragana optotype group 41, a polarization test optotype group 43, and a red-green test group. Target group 44 for astigmatism test, target group 45 for astigmatism test,
A stereoscopic visual target 46 and the like are provided.

FIGS. 10 and 11 show specific structures of the receiving frame 51 and the spacer 52 for adjusting the position of the concave mirror 8 along the direction of the optical axis L1. That is, a hole 53 through which light can pass is provided at the center, and the receiving frame 51 provided with the concave receiving portion 54 is placed inside the apparatus main body 20 such that the optical axis L1 passes through the center of the hole 53. A mirror holder 55 having an annular flange portion 56 and having the concave mirror 8 mounted thereon is directly fixed to the receiving frame 51 as shown in FIG. 10 or fixed to the receiving frame 51 as shown in FIG. Receiving frame 51 via an annular spacer 52 having a thickness of
The eye E and the apparatus main body 2 shown in FIG.
A state in which the distance between the subject E and the subject E is 1.1 m, and a state in which the distance between the subject's eye E and the apparatus main body 20 is 0.7 m shown in FIG. 8 are realized.

According to the visual acuity chart presenting apparatus of the second embodiment, the concave mirror 8 of the optotype optical system 23 is moved in the optical axis direction in accordance with the change in the distance of the eye E to the apparatus body 20. The concave lens 31 is inserted into the optical path of the optotype optical system 23 so that the imaging magnification of the optotype images of various optotypes arranged in a circular shape illuminated by the illumination system 22 is kept constant. Regardless of the distance between the subject's eye E and the apparatus body 20, the optotype images of the respective optotypes can be presented to the subject's eye E in a fixed size, regardless of the size of the subject's eye E. Accurate optometry can be performed.

In the second embodiment described above, the configuration in which the concave lens 31 is inserted near the rotary plate 21 as the auxiliary optical member has been described. However, the concave lens 31 may be inserted in the optical path of the target optical system. It is not particularly limited.

In the second embodiment, the concave lens 31 is used as the auxiliary optical member. However, even in the configuration using the convex lens, similarly to the second embodiment, the subject's eye E and the apparatus main body can be used. The imaging magnification of the optotype images of various optotypes can be kept constant regardless of the distance from the distance 20.

[0029]

According to the first aspect of the present invention, a target image of a fixed size can be presented to the subject's eye irrespective of the distance between the subject's eye and the apparatus main body, and the space for the optometry space can be improved. It is possible to provide a visual acuity chart presenting apparatus capable of executing accurate optometry for an eye to be inspected regardless of its size.

[Brief description of the drawings]

FIG. 1 is a perspective view of a visual acuity table presentation device according to a first embodiment.

FIG. 2 is a cross-sectional view of the visual acuity table presentation device according to the first embodiment.

FIG. 3 is a cross-sectional view of the visual acuity table presentation device according to the first embodiment.

FIG. 4 is a partial cross-sectional view illustrating a groove frame portion for a concave mirror according to the first embodiment.

FIG. 5 is an explanatory diagram illustrating a use state of the visual acuity table presentation device according to the first embodiment;

FIG. 6 is a front view of a visual acuity table presentation device according to a second embodiment.

FIG. 7 is a cross-sectional view of a visual acuity table presentation device according to a second embodiment.

FIG. 8 is a cross-sectional view when the position of a concave mirror is changed and an auxiliary optical member is used in the visual acuity table presentation device of the second embodiment.

FIG. 9 is a schematic front view of a rotating plate provided with various targets used in the second embodiment.

FIG. 10 is a schematic sectional view showing a receiving frame for changing the position of a concave mirror according to the second embodiment.

FIG. 11 is a schematic sectional view showing a receiving frame and a spacer for changing the position of a concave mirror according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Device main body 2 Opening 4 Optotype plate 5 Optotype 6 Optotype optical system 7 Half mirror 8 Concave mirror 10 Concave lens 20 Device main body 21 Rotating plate 22 Illumination system 23 Optotype optical system 31 Concave lens

Claims (1)

[Claims] 1. A visual acuity chart presenting apparatus including a visual acuity optical system using a concave mirror and a semi-transparent mirror for forming a visual target image of a visual target attached to a visual acuity chart at a predetermined distance from an eye to be examined. A visual acuity chart, wherein an auxiliary optical member is used as the optotype optical system to form the optotype image at a constant distance in response to a change in distance of the subject's eye with respect to the apparatus main body. Presentation device.