JPH01236031A - Eyesight evaluating device - Google Patents

Abstract

PURPOSE:To cause a subject to take a binocular eyesight test without using a polarized light test chart by synchronizing the conversion of an image displayed on a display picture with the opening and closing of optical shutters for the right eye and the left eye at a high speed. CONSTITUTION:At the time of an operation mode A, the image for the right eye is displayed on the picture of a display 1, and at the time of an operation mode B, the image for the left eye is seen only with the left eye. The synchronization of the conversion between the operation mode A and operation mode B to the conversion of the image on the picture of the display 1 is executed by a simple synchronizer. Since optical shutters 3 and 4 utilize liquid cells, the opening and closing can be executed at a high speed in synchronizing to the high-speed image conversion of the display 1. When the period of the conversion exceeds the degree of 1/60sec, a person 2 to be measured is made to have a feeling that one image, in which the image for the right eye and image for the left eye are combined, is seen with both eyes. When the both-eyesight test is executed in such a condition, the both-eyesight test equal to or above the case of using the conventional polarized test chart can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a visual acuity evaluation device capable of performing a binocular vision test.

(Prior art) Two types of images (for example, a vertical line and a horizontal line) that define planes of polarization that are orthogonal to each other are drawn on a single polarization test chart using a polarizing film. A polarizing member for the right eye and a polarizing member for the left eye that define the plane of polarization are prepared, and the test subject can perform a cross test or an error test by viewing this polarization test chart through the polarizing member for the right eye and the polarizing member for the left eye. Devices that allow binocular vision tests such as isoimage tests or stereoscopic vision tests are known.

(Problem to be Solved by the Invention) However, in these conventional devices that utilize image separation using polarized light, in order to perform various binocular vision tests, a large number of special polarization test charts such as those described above are required. I had to be prepared.

In addition, an example is a test for correctly recognizing when an object is lined up with another object in a continuous movement in which an object that was behind it gradually approaches and then comes out in front of it. It was not possible to perform a dynamic stereoscopic test (such as the required test).

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to enable a binocular vision test to be performed without preparing a polarization test chart, and to enable a dynamic stereoscopic vision test to be easily performed.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a display device operable to alternately display a right eye image and a left eye image at high speed, and a display device operable to alternately display right eye images and left eye images. placed between the screen and the subject, each operable to transmit or block light by applying and removing an electric field;
A right eye optical shutter and a left eye optical shutter using a liquid crystal cell, and when a right eye image is displayed on the screen of the display device, the right eye optical shutter is in a transmitting state and the left eye optical shutter is in a transmitting state. When the light shutter for the right eye is in the blocking state and the left eye image is being displayed, the right eye light shutter is in the blocking state and the left eye light shutter is in the transmitting state in synchronization with the screen display of the display device. A visual acuity evaluation device is provided, comprising a light shutter and a synchronization device capable of operating a left eye light shutter.

(Function) When performing a binocular vision test using the visual acuity evaluation device of the present invention, right-eye images and left-eye images are alternately displayed at high speed on the screen of the display device.

This image itself does not need to be a polarized image. On the other hand, due to the action of the synchronization device, the subject can view the right eye image only through the right eye optical shutter, and the left eye image only through the left eye optical shutter.

The conversion of the image displayed on the display screen and the opening and closing of the right-eye and left-eye optical shutters are performed synchronously at high speed (for example, at a 1/60 second cycle), allowing the subject to use both eyes to It feels like you are viewing both the eye image and the left eye image at the same time. In this state, the subject can take a binocular vision test without using a polarization test chart.

When performing a dynamic stereoscopic vision test, a large number of images whose positions are slightly shifted are continuously displayed together with a fixation point in each of the right eye image display and the left eye image display.

As a result, the subject can feel as if an image is moving forward or backward relative to the fixation point.

(Embodiment) FIG. 1 diagrammatically explains the configuration and arrangement of an embodiment of the visual acuity evaluation device according to the present invention.

First, a first example will be described. Reference numeral 1 denotes a display device, and various devices such as a CRT1 liquid crystal display or a plasma display having a high-speed screen conversion capability can be used. By connecting the display device 1 to, for example, a computer (not shown), it is possible to quickly and continuously display desired images. A right eye optical shutter 3 and a left eye optical shutter 4 using liquid crystal cells are arranged between the display device 1 and the non-measuring person 2.

These optical shutters 3.4 can be attached to an optometrist frame (not shown). For convenience of explanation, the optical shutters in the closed state, that is, in the state that blocks light, are shown with diagonal lines, and the optical shutters in the open state, that is, in the state that transmits light, are not shown with diagonal lines. .

The optical shutter 3.4 can be of various forms, for example using a twisted nematic mode liquid element. This liquid crystal element has a liquid crystal cell structure in which a liquid crystal cell twisted at a twist angle of 90 degrees is arranged between a pair of polarizers. If the polarizers on both sides are in a parallel Nicol state (the polarization direction on both sides is the same), and the polarization direction of the polarizer on the incident light side matches the long axis direction of the liquid crystal molecules on the incident light side, there is no electric field. When the light passes through the polarizer on the incident light side, its plane of polarization is rotated by 90 degrees along the twist of the liquid crystal cell, but since the polarization direction of the polarizer on the opposite side is perpendicular to this, the light The light cannot pass through this polarizer, and the light shutter is in a blocking state (closed state). However, when a certain electric field or more is applied to the liquid crystal cell, the liquid crystal molecules align their long axes almost parallel to the direction of the electric field, so the light that passes through the polarizer on the incident light side maintains linear polarization.
Since it can pass through the polarizer on the opposite side, the light beam is in a transparent state (open state).

In addition, if the polarization direction of the polarizer on the opposite side is arranged to be orthogonal to the polarization direction of the polarizer on the incident light side (in the case of orthogonal double polarizers), the operation is opposite to the previous one, and light is emitted in an electric field-free state. The shutter is in a transmitting state (open state), and when an electric field is applied, it is in a blocking state (closed state).

Although any type of optical shutter can be applied to the optical shutter in the present invention, for example, if the optical shutter 3 for the right eye is in a parallel Nicols state and the optical shutter 4 for the left eye is in a crossed Nicols state, both optical shutters can be used. By simultaneously applying an electric field to or removing the electric field, there is an operation mode A in which the right eye optical shutter 3 is opened and the left eye optical shutter 4 is closed, and the right eye optical shutter 3 is closed. It is possible to alternately obtain operation mode B in which the left eye optical shutter 4 is opened. Of course, it is also possible to leave both the optical shutters in the parallel or crossed Nicols state and apply the electric field to each of the right-eye optical shutter 3 and the left-eye optical shutter 4 alternately.

When the operating mode is entered, a right eye image is displayed on the screen of the display device 1, and the subject 2 sees this image only with the right eye. On the other hand, in operation mode B,
The person to be measured 2 views the left eye image switched and displayed on the screen of the display device 1 only with his left eye.

Synchronization between the conversion between the operation mode A and the operation mode 8 and the conversion of the image on the screen of the display device 1 can be performed by a synchronization device (not shown) using a simple electric circuit or the like.

Since the optical shutter 3.4 utilizes a liquid crystal cell as described above or in another embodiment, it can be opened and closed at high speed in synchronization with the high-speed image conversion of the display device 1. When the period of this conversion exceeds approximately 1/60 seconds, the person to be measured 2 feels as if he or she is viewing a single image with both eyes, which is a combination of a right eye image and a left eye image.

A binocular vision test can be performed in this state.

When the visual acuity evaluation device according to the present invention is used, it is possible to perform a binocular vision test that is equivalent to or better than when using a conventional polarization test chart.

2 to 5 show the display device 1 when performing a typical binocular vision test using the visual acuity evaluation device of the present invention.
A right-eye image and a left-eye image that are alternately displayed on the screen are shown superimposed on each other.

FIG. 2 shows a cross test image used for measuring horizontal and vertical phoria. For example, vertical lines 7a and 7b are images for the right eye, and horizontal lines 8a and 8b are images for the left eye.

FIG. 3 is an anisotropy test image used for measuring anisotropy between the left and right eyes. This image is for use only.

FIG. 4 is a rotational phoria image test used to measure rotational phoria, including lines 12a to 12d and fixation point 10.
is the image for the right eye, and the scales 13a to 13b and the fixation point 10 are the image for the left eye.

FIG. 5 is a binocular balance test image for measuring the balance of binocular visual acuity, in which the R portion is an image for the right eye and the L portion is an image for the left eye.

Above, we have explained images for typical binocular vision tests, but there are also other images such as red and green tests. Also,
The method of evaluating the results of these binocular vision tests is well known in the art, so a description thereof will be omitted.

FIG. 6 is a series of images for conducting a dynamic stereoscopic vision test that can be performed for the first time using the visual acuity evaluation apparatus of the present invention.

In any mode (a) to mode (e),
Although the right eye image and the left eye image are shown superimposed, the optotype R and the fixation point 10 become the right eye image, and the optotype and the fixation point 10 become the left eye image. As is clear from the figure, the optotype R and the optotype gradually approach each other while moving from mode (a) to mode (c), and the distance between them becomes narrower, and from mode (c) to mode ( On the contrary, they move away from each other while moving to e). In reality, a large number of images with even more subtle shifts are prepared between each mode. In principle, the screen of the display device 1 can display an image for the right eye in mode (a), an image for the left eye in mode (a), an image for the right eye in mode (b), and an image for the left eye in mode (b). The mode (e
), the subject sees the upper and lower triangular optotypes gradually approach the fixation point 10 from behind the fixation point 10, and in mode (c), they line up with the fixation point 10. ,
This time, it appears to be moving forward past fixation point 10. The subject is asked to give a signal when he/she recognizes that the triangular visual target is lined up with the fixation point 10, and the accuracy of the signal is measured.

Although several examples of binocular vision tests have been described above, it goes without saying that various conventional monocular vision tests can also be performed using the visual acuity evaluation apparatus of the present invention.

In this case, the right eye image or left eye image is displayed in a blank state.

The display device 1 connected to the computer includes
You can display unlimited types of images and also
You can easily design your own screens and change or delete images. Furthermore, it can be used in bright places, and you can easily adjust the screen brightness and contrast.

(Effects of the Invention) The visual acuity evaluation device of the present invention can perform a binocular vision test without preparing expensive and limited number and type of polarization test charts, and can perform a dynamic stereoscopic vision test. can be easily implemented.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration and arrangement of an embodiment of the visual acuity evaluation device according to the present invention. FIG. 2 is a diagram showing a right eye image and a left eye image, which are alternately displayed on the screen of a display device, superimposed when performing a cross test using the visual acuity evaluation device of the present invention. FIG. 3 is a diagram illustrating a right eye image and a left eye image that are alternately displayed on the screen of a display device, overlapping each other, when performing an anisotropy test using the visual acuity evaluation device of the present invention. FIG. 4 is a diagram showing a right eye image and a left eye image that are alternately displayed on the screen of a display device, superimposed when performing a rotational tropia test using the visual acuity evaluation device of the present invention. FIG. 5 is a diagram showing a right eye image and a left eye image, which are alternately displayed on the screen of a display device, superimposed when performing a binocular balance test using the visual acuity evaluation device of the present invention. FIG. 6 is a diagram showing images continuously displayed on the screen of the display device when performing a dynamic stereoscopic vision test using the visual acuity evaluation device of the present invention, and is a diagram showing images (a) to e). In each case, a right-eye image and a left-eye image that are displayed alternately are shown superimposed. 1. Display device 2: Person to be measured 3: Optical shutter for right eye 4 Engraving of drawing of optical shutter for left eye (no change in content) 1. Method) Patent Application No. 64625 of 1986 2 Name of the invention Visual acuity evaluation device 3 Relationship to the person making the amendment Case Applicant address Name Kenji Bessho 4 Agent address 2-2 Otemachi, Chiyoda-ku, Tokyo No. 1 Shin-Otemachi Building 206 Ward Telephone 270-6641-6646 6 Subject to correction

Claims (1)

[Scope of Claims] A display device operable to alternately display right-eye images and left-eye images at high speed; and a display device disposed between the screen of the display device and the subject, each of which has an electric field. A right eye optical shutter and a left eye optical shutter using a liquid crystal cell operable to transmit or block light by application and removal, and when a right eye image is displayed on a screen of the display device. The right eye optical shutter is in a transmitting state and the left eye optical shutter is in a blocking state, and when the left eye image is displayed, the right eye optical shutter is in a blocking state and the left eye optical shutter is in a transmitting state. a synchronization device capable of operating the right eye optical shutter and the left eye optical shutter in synchronization with the screen display of the display device.