JP3262838B2 - Eye chart device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual acuity chart apparatus, and more particularly, to an improvement in a visual acuity chart apparatus that presents a target to a subject and performs an eye examination of the subject in a subjective manner.

[0002]

2. Description of the Related Art A conventional visual acuity chart device of this type is electrically driven,
Regardless of the manual type, optometry with a built-in correction optical system is arranged in front of the subject's eyes, and the subject is presented with an optotype attached to a visual acuity chart through the correction optical system for optometry. Was.

That is, the optometry is performed while the face of the subject is in close contact with the optometry means.

[0004]

However, in the case of the conventional visual acuity table apparatus, the face of the subject is in close contact with the optometry means. Gave some kind of oppression and anxiety to the elderly. Such feelings of oppression and anxiety are caused by the psychological state of the subject,
This affected the condition of the eye and hindered accurate collection of optometry data.

Accordingly, the present invention is an improved visual acuity charting apparatus which can improve the configuration, collect accurate optometric data without giving the subject a feeling of oppression and anxiety, and have no problem in hygiene. The purpose is to provide.

[0006]

[0007]

According to the first aspect of the present invention,
In a visual acuity chart apparatus for presenting an optotype to a subject and performing an eye examination of the subject, an eye position for detecting a distance from a position of the optotype to a position of an eye of the subject facing the optotype. Detecting means, a correction optical system arranged in the vicinity of the target, and a projection image of the correction optical system arranged in the vicinity of the correction optical system.
And a projection optical system that adjusts the position of the projection image generated by the correction optical system based on the detection result of the eye position detection means.

[0008]

The operation of the visual acuity chart device having the above-described configuration will be described below.

[0009]

According to a first aspect of the present invention, the eye position detecting means of the visual acuity table apparatus detects a distance from the position of the target to the position of the eye of the subject facing the target. The projection optical system generates a projection image by the correction optical system based on the detection result of the eye position detection means.
Adjust the formation position. Thus, the subject can visually check the optotype via the projection image of the correction optical system in front of the eye and perform the optometry. , While feeling uneasy,
Since the target is viewed through the projected image, there is no problem in terms of hygiene. Further, a projection image of the correction optical system in front of the eye can be accurately generated.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail.

A visual acuity chart apparatus 1 shown in FIG. 1 has a box-shaped main body 2, a lens barrel 3 disposed horizontally from the front to the rear of the main body 2, and a rear surface disposed on the rear side of the main body 2. A visual acuity table 5 provided with a visual target such as a Landolt mark for visual acuity inspection provided with an illuminating unit 4, a projection optical system 6, and a correction optical system 7 incorporated into the lens barrel 3 in order from the front to the back of the main body 2. And a relay lens 8 for converting a light beam from the target attached to the eyesight table 5 into parallel light.

The projection optical system 6 includes a first relay lens 9 on the correction optical system 7 side and a second relay lens 9 facing the eye of the subject.
By setting the focal lengths of the first and second relay lenses 9 and 10 appropriately, the projection image of the correction optical system 7 can be The pseudo lens 7a is generated in front of the subject's eye E facing away from the user by about 5 m.

That is, the correction optical system 7 and the pseudo lens 7a
Is conjugate to the eyesight table 5.

The correction optical system 7 is composed of a turret type lens group (spherical lens group, cylindrical lens group) like the correction optical system of the ordinary optometry means, and can be switched at any time by remote operation means (not shown). .

Then, by making the power of the correction optical system 7 generally positive, the eye E is projected through the projection optical system 6.
Is irradiated with convergent light, and the power is made to be totally zero so that the eye E is irradiated with parallel light.

The relay lens 8 converts the light beam from the target attached to the visual acuity table 5 into parallel light, and the projection optical system 6 projects the image of the target together with the correction optical system 7 toward the eye E. Is to be canceled.

Next, the operation of the visual acuity chart device 1 will be described.

The projection optical system 6 of the visual acuity table apparatus 1 actually projects the correction optical system 7 disposed near the visual acuity table 5 and outputs the projected image of the correction optical system 7 to the back illumination unit 4.
Is generated as a pseudo lens 7a in front of the eye E of the subject facing the visual acuity table 5 illuminated by, for example, 5 m away.

As a result, the subject can see the pseudo lens 7 in front of the eyes.
The optotype of the eyesight table 5 can be visually recognized through a to perform an optometry, and a feeling of oppression and anxiety is eliminated as compared with a case where an optometry is performed in a state of being in contact with a conventional optometry unit.
Since the visual acuity table 5 is viewed through the pseudo lens 7a, there is no problem in terms of hygiene.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS.

A visual acuity chart apparatus 1A shown in FIGS. 2 and 3 has a box-shaped main body 20 and a pair of left-eye and right-eye lenses provided horizontally from the front to the back of the main body 20. Cylinder 3
And a pair of visual acuity tables 5 provided with optotypes such as a pair of back lighting units 4 and Landolt marks arranged on the back side of the main body 20.
And a TV camera 21 arranged at an intermediate position between the pair of lens barrels 3.

For each of the lens barrels 3, the light beams from the projection optical system 6, the correction optical system 7, and the optotype attached to the visual acuity table 5, which are incorporated in order from the front to the back of the main body 20, are made into parallel light. And a relay lens 8.

The second relay lens 10 of each of the projection optical systems 6 faces the front surface of the main body 20 while the T
The imaging lens unit 22 of the V camera 21 also faces the front of the main body 20.

As shown in FIG. 2, an optometry table 30 is disposed at a position, for example, 5 m away from the visual acuity table apparatus 1A, and the subject 50 sitting on a chair 31 disposed near the optometry table 30 It opposes the eye chart device 1A.

On the optometry table 30, a control box 40 having a display section 41 such as a liquid crystal display and an input section 42 is mounted.

FIG. 4 shows a control system including the visual acuity table apparatus 1A and the control box 40. The control system includes a program memory 61 storing an entire operation program and a control unit 62 including a control unit 60 for performing overall control based on the operation program.

The control unit 60 includes the control box 4
0, the TV camera 21, and the distance from the visual acuity table apparatus 1 </ b> A to the face (for example, the position of the nose) of the subject 50 based on the imaging information of the subject 50 by the TV camera 21. A distance calculation unit 63 that also calculates the interpupillary distance PD of the person 50 is connected. The TV camera 21 and the distance calculation unit 63 constitute an eye position detection unit 70.

The control unit 60 is connected to a projection optical system drive unit 64 for adjusting the position of the projection optical system 6 and a correction optical system drive unit 65 for adjusting the position of the correction optical system 7. I have.

As shown by the dotted line in FIG. 5, the screen of the display unit 41 has a pair of left and right corresponding to the interpupillary distance PD of the subject 50 based on the calculation result of the eye position detecting means 70. Is displayed.

A mark 81 such as an X mark indicating the pupil of the subject 50 is also displayed on the alignment image 80.

Next, the operation of the eyesight chart apparatus 1A will be described.

The TV camera 21 of the eye position detecting means 70
Captures an image of the face of the subject 60 facing the subject at a predetermined distance, and uses the captured image as image information as an electrical signal.
0 to the distance calculation unit 63. The distance calculation unit 63
The distance to the face of the subject 50 and the pupil distance PD are calculated based on the image information, and the calculation result is sent to the control unit 60.

As a result, under the control of the control unit 60, the projection optical system driving unit 64 displaces the position of the projection optical system 6 to project the projection image of the correction optical system 7, that is, the pseudo lens 7a.
It is generated at a position 12 cm in front of the eye of 0.

Thus, the same function as that of the visual acuity chart apparatus 1 is exerted, and the pseudo lens 7a can be accurately and reliably generated in front of the subject 50.

In this case, the display unit 41 also has a pair of left and right alignment images 80 corresponding to the interpupillary distance PD of the subject 50 based on the calculation result of the distance calculation unit 63, and marks 81 such as X marks. Is displayed, the examiner can see the alignment image 8
It is possible to control the generation operation of the pseudo lens 7a while watching the mark 0 and the mark 81.

The present invention is not limited to the embodiment described above, and various modifications can be made within the scope of the invention.

[0038]

[0039]

According to the first aspect of the present invention, since the above-described configuration is employed, it is possible to provide a visual acuity chart apparatus capable of accurately positioning the projection image of the correction optical system with respect to the eye.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing another embodiment of the present invention.

FIG. 3 is a schematic plan view showing another embodiment of the present invention.

FIG. 4 is a block diagram showing a control system according to another embodiment of the present invention.

FIG. 5 is a plan view showing a display example of a display unit according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Visual acuity table apparatus 1A Visual acuity table apparatus 2 Main body 5 Visual acuity table 6 Projection optical system 7 Correction optical system 7a Pseudo lens 8 Relay lens 21 TV camera 63 Distance calculator 70 Eye position detecting means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61B 3/00-3/16

Claims (1)

(57) [Claims] In a visual acuity chart apparatus for presenting an optotype to a subject and performing an eye examination of the subject, a distance from a position of the optotype to a position of an eye of the subject opposing the optotype. An eye position detecting means for detecting a correction optical system disposed in the vicinity of the target, and a correction optical system disposed in the vicinity of the correction optical system.
And a projection optical system that generates a projection image of the above and adjusts a generation position of the projection image by the correction optical system based on the detection result of the eye position detection unit.