JPH0838421A - Optometry device - Google Patents

Abstract

PURPOSE:To apply masking to a target at the center section of a screen and minimize the number of masks by controlling a driving means to move the selected presentation target nearly to the center of the screen based on the detection by a target detecting means and the signal of a target selecting means. CONSTITUTION:When an eyechart roll film 2 is unwound on an eyechart upper roller and a mark is detected by an eyechart film initial position detecting photoelectric switch 14A, the photoelectric switch 14A is turned off, and the eyechart roll film 2 is set to the start position. The signal constituent digitized with the infrared signal from a remote control 46 from the infrared modulation light in a light receiving preamplifier 45 and a detecting circuit 44 is extracted, and the command signal for presenting the target corresponding to the signal constituent is generated in a CPU 40, a RAM 41, and a ROM 42. The command signal drives an eyechart upper pulse motor 16 via an input/output circuit 43, and the target to be presented is moved nearly to the center of a screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual acuity test apparatus capable of arranging a plurality of visual acuity measuring targets in one screen and switching to a screen having other visual acuity measuring targets. .

[0002]

2. Description of the Related Art A visual chart,
Astigmatism charts, stereoscopic charts, and many other targets are required, so it is economical to store all these targets in one screen.
It is practically impossible due to locational constraints. Therefore, a general one is one in which main visual targets are extracted and configured as one screen, and a system in which the entire visual targets are divided and a plurality of visual targets are provided on the same screen is generally used. For these devices as well, a mechanism has been conceived for specifying what should be read by the subject from among the plurality of optotypes for the purpose of smoothing the response between the examiner and the subject.

[0003]

Conventionally, as a means for specifying a certain optotype from a plurality of optotypes, a lamp is arranged behind each of the optotypes and corresponds to a combination of the optotypes to be presented. There was one that turned on the lamp. However, since the target itself is not replaced in this device, the device becomes large and the subject changes the position of the target,
It has the drawback of having to look at the target. Further, there is known a projection type visual acuity test device (chart projector) for projecting a visual target image on a screen, in which a rotary disc with a mask is superposed on a rotary disc with a visual target. FIG. 10 is a schematic diagram of this device. When the visual acuity chart disk 101 rotates about the rotation center 102, the optotype section 103 is switched. The mask plate disk behind the visual acuity table disk also rotates about 102 as a center of rotation, and the lateral mask 104A overlaps the illustrated visual acuity value series. Next, when the horizontal mask is overlaid on the visual acuity value row above it, since the horizontal mask 104A is inclined, it is necessary to overlay another horizontal mask 104B. In this way, in order to superimpose a horizontal mask on each visual acuity value column, each mask is required for each column, and to present one character, a mask for each character is required. As described above, in the projection type visual acuity test device (chart projector) in which the rotary disc with the mask is superposed on the rotary disc with the visual target, the moving direction of the disc draws an arc, so that Masking cannot be performed at the center of the screen, and the number of required masks is extremely large, which complicates the apparatus.

In view of the above drawbacks, it is a technical object of the present invention to provide a visual acuity test apparatus capable of masking the optotype at the center of the screen and minimizing the number of masks.

[0005]

According to the present invention, in order to achieve the above object, a plurality of optotypes are arranged in one screen, and switching to a screen having another optotype can be performed by a driving means. In a possible visual acuity test apparatus, an optotype selecting means for selecting an optotype to be presented to the subject, an optotype detecting means for detecting the position of the optotype, and an in-screen display so as to overlap the presented screen. Mask means having a mask for presenting some of the targets and mask driving means for moving the mask, mask detection means for detecting the position of the mask, detection by the mask detection means and selection of the targets Mask control means for controlling the mask driving means based on the signal of the means, and the target to be presented selected based on the signal of the detection of the target detection means and the target selection means in the center of the screen. Drive means to move to It is characterized by having a target control means for controlling.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings of the embodiments. FIG. 1 is an external view of a visual acuity test apparatus body according to a first embodiment of the present invention, in which optotypes other than a horizontal line at the center of the screen are masked. FIG. 2 is an external view of the apparatus when the mask roll film 4 for specifying the optotypes to be read by the subject from the plurality of optotypes in one screen is not used. Reference numeral 1 is a housing of the apparatus, 2 is a roll film for a visual acuity table to be presented to the subject, and 3 is a light receiving portion for a remote controller for switching the optotypes by a remote control. The shaded portion in FIG. 1 indicates a portion 4 where the light of the lamp 13 is blocked by the mask roll film 4.

FIG. 3 is a sectional view taken along the line AA 'in FIG.
FIG. 3 is a sectional view taken along the line BB ′ of FIG. Upper row of eyesight chart
A visual acuity roll film 2 on which a visual acuity test target is drawn is wound between a roller 5 and a lower visual acuity chart roller 8, and the visual acuity chart upper side motor 16 and the visual acuity chart lower side motor 16 are wound. At 17, the upper roller 5 and the lower roller 8 of the visual acuity table are rotated to switch the screen. 14A is a photoelectric switch for detecting the initial position of the roll film for the visual acuity table arranged on the left side of the screen, and on the right side of the screen is a photoelectric switch for detecting the position of the optotype (31 in FIG. 6).
There is A). Reference numeral 13 is a lamp for illuminating the visual acuity roll film 2 from the back side, which is turned on by a relay (51 in FIG. 8). Reference numerals 9 and 12 are a mask upper roller and a mask lower roller for masking a target other than a specific target from a plurality of targets presented on the screen, and a mask roll film. 4 is wound, the upper motor 18 for the mask, the lower motor 24 for the mask, the pulleys 21, 23, 2
The upper roller 9 for the mask and the lower roller 12 for the mask are rotated by 9, 27 and the belts 22, 28 to switch the screen. Reference numeral 14B is a photoelectric switch for detecting the initial position of the mask film, which is arranged on the left side of the screen, and there is a photoelectric switch 31B for detecting the position of the same shape on the right side of the screen.

5 and 6 are explanatory views of a position detecting mechanism for presenting a desired film on the screen. First, the visual acuity chart roll film 2 and the mask roll film 4 are marked with marks for indicating the start position. In this embodiment, black belt-shaped marks 30A and 3 are provided at the start position.
Since there is 0B, the position where light is blocked is detected by the film initial position detection photoelectric switches 14A and 14B. Next, marks 32A and 32B for displaying the displacement from the start position are marked on each screen on the visual acuity table roll film 2 and the mask roll film 4. The mark is detected by the position detecting photoelectric switches 31A and 31B, and each film is stopped at a predetermined position.

FIG. 7 is a diagram for explaining the operation of the mask roll film. The mask roll film 4 has a rectangular light transmitting portion (horizontal mask) corresponding to one row of the visual acuity test target. The light transmitting portion may be a simple opening as long as the strength can be maintained. Further, in this embodiment,
As shown in FIG. 3, the mask roll film 4 is placed on the lamp side by the visual acuity roll film 2, but since the positional relationship between the two is not important, they are opposite in description. .

The operation of the embodiment having the above construction will be described below. First, the operation for presenting the visual acuity test target will be described. When the power is turned on, the motor 16 on the upper side of the visual acuity table is allowed to rotate freely without applying a voltage, and the motor 17 on the lower side of the visual acuity table is rotated by applying a voltage, and the roll film 2 for the visual acuity table is rotated. Rewinding to the upper roller 8 of the visual acuity chart, photoelectric switch 14A for detecting the initial position of the visual acuity chart film
When the mark 30 is detected by, the photoelectric switch 14A is turned off and the visual acuity roll film 2 is set at the start position. In the film stopped state, the voltage switching circuit 48 keeps the voltage applied to the upper and lower pulse motors of the visual acuity table below the rated value, and keeps the upper and lower rollers of the visual acuity table in the absence of heat generation. Prevents film slack.

An infrared signal emitted from a remote controller 46 from the outside of the device is received by the light receiving preamplifier 4 attached to the housing 1.
5. The detection circuit 44 extracts the digitized signal component from the infrared modulated light, the input / output circuit 43, the CPU 40,
A command signal for presenting the optotype corresponding to the signal component is generated by the RAM 41 and the ROM 42. The command signal is passed through the input / output circuit 43, the voltage is maximized by the motor drive circuit 47 and the voltage switching circuit 48, and the upper pulse motor of the visual acuity table
Drive the motor 16. At this time, the lower motor 17 of the visual acuity table
Since a voltage is not applied to the lower winding roller 8, the lower winding roller 8 can freely rotate, so that high-speed winding can be performed even though the torque of the drive pulse motor is small.

The feeding position of the visual acuity roll film 2 is shown in FIG.
The photoelectric switch 3 is provided with the mark 32A for detecting the film position of
It can be detected by 1A, the mark position before the one to be presented is detected, and deceleration for stopping is started. When the motor on the upper side of the visual acuity table on the driving side is decelerated, the lower winding roller 8 freely rotates and the film is sent out more than necessary due to the inertia moment. A weak braking torque is applied by intermittently applying a pulsed voltage. As the speed decreases, the cycle of intermittently applied voltage is shortened and stopped. By the above operation, it is possible to prevent the film from loosening during deceleration and stop, reduce the tensile force applied to the film, and increase the stop position accuracy.

Next, the operation of the mask roll film will be described. Drive and roll of the mask roll film 2
The method of controlling the data is basically the same as that of the roll film for the visual acuity chart. That is, when the power is turned on, the mask lower motor 24 is rotated, the mask roll film 4 is rewound onto the mask lower roller 12, and the mask film initial position detection photoelectric switch 14B is used. -Detecting mark 30B, the mask roll film 4 is set at the start position. FIG. 7 shows the moving direction of the mask roll film 4. An infrared signal for instructing a specific optotype sequence from an external remote controller 46 is attached to the housing 1. The light receiving preamplifier 45, the detection circuit 44, the input / output circuit 43, the CPU 40, R
A command signal for determining the position of the mask corresponding to the signal component is generated via the AM 41 and the ROM 42. The command signal passes through the input / output circuit 43 and the motor drive circuit 5
2. The voltage switching circuit 55 maximizes the voltage to drive the mask upper pulse motor 18. At this time, no voltage is applied to the mask lower pulse motor 24 as in the case of the upper eye motor. The feed position of the mask roll film 4 can be detected by the photoelectric switch 31B of the mark 32B for detecting the film position shown in FIG. 6, and the mark position before the one to be presented is detected to stop. Enter the deceleration of. When the upper mask motor on the driving side is decelerated, the lower winding roller 1
In No. 2, the film is sent out more than necessary, so a weak braking torque is applied by intermittently applying a pulse voltage as in the pulse motor on the upper side of the visual acuity chart. As the speed decreases, the cycle of intermittently applied voltage is shortened,
Stop.

Next, the operation of presenting a specific optotype sequence on the same screen will be described. In FIG. 7, the visual acuity table roll film 2 is moved to present a predetermined visual acuity table screen, and then the mask roll film 4 is moved to dispose the horizontal mask at the center of the screen. As a result, it is possible to present only the horizontal one-line optotypes 2b shown in the figure. Next, when presenting the optotypes 2a in a horizontal row, the visual acuity table film 2 is moved by the optotype array changeover switch (not shown) on the remote controller 46 while the transverse mask is fixed, and 2a is presented in the center of the screen. Similarly, when presenting one horizontal row of the targets 2c, it is possible to move the 2c to the center of the screen with the horizontal mask fixed. First of all
In the embodiment, it is possible to present all the horizontal one-line optotypes in the center of the screen with one horizontal mask.

FIG. 9 is a diagram for explaining the second embodiment.
The visual acuity chart roll film 2 and the one-character presentation mask 4b on the mask roll film 4 are movable in mutually orthogonal directions. Since the driving method of each film is the same as that of the first embodiment, it is omitted. The one-character presentation mask 4b is movable in the left-right direction in the drawing, and can be moved to a position corresponding to the visual target 2i to present only 2i. Similarly, 2h, 2j, 2
It is also possible to present k. In addition, by moving the mask roll film in the left-right direction while moving the visual acuity film 2d to the position 2h in the figure, 2d to 2g can be obtained.
Can be presented. Similarly, 2e to 2o can be presented. Thus, in the second embodiment, one character mask 1
Only by preparing one, one character can be presented for all the targets 2d to 2o. If a vertical mask is used, all the targets can be presented in a single vertical line with one vertical mask. Although the first and second embodiments described above use the film, the same effect can be obtained by moving a plate-shaped object for both the visual acuity chart and the mask.

[0016]

As described above, according to the present invention,
The subject was able to see the target at almost the center of the screen without moving the line of sight. For example, when presenting a line of optotypes to a subject, the optotypes can be presented while moving the optotypes while keeping the mask fixed in the center, so that the number of masks can be reduced.

[Brief description of drawings]

FIG. 1 is an appearance of a main body of a visual acuity test apparatus using a lateral mask for indicating a target to be read by a subject from a plurality of targets in one screen, which is a first embodiment of the present invention. It is a figure.

FIG. 2 is an external view of a main body of a visual acuity test apparatus when a mask is not used.

FIG. 3 is a sectional view taken along the line AA ′ of FIG.

FIG. 4 is a sectional view taken along the line BB ′ of FIG.

FIG. 5 is an explanatory diagram of a position detection mechanism for presenting a desired film on the screen.

FIG. 6 is an explanatory diagram of a position detection mechanism for presenting a desired film on the screen.

FIG. 7 is a diagram for explaining an operation when a horizontal mask is used.

FIG. 8 is a block diagram of a drive unit of a visual acuity table and a roll film for a mask.

FIG. 9 is a diagram for explaining the operation of the one-character mask.

FIG. 10 is a schematic diagram of one conventional device.

[Explanation of symbols]

 2 Sight table roll film 4 Mask roll film 14,31 Photoelectric switch 16 Sight table upper side (pulse) motor 17 Sight table lower side (pulse) motor 18 Mask (pulse) upper motor 24 mask (Pulse) lower motor 30 film initial position mark 40 CPU

Claims (1)

[Claims] 1. A visual acuity test apparatus in which a plurality of optotypes are arranged in one screen and can be switched to a screen having another optotype by a driving means. An optotype selecting means for selecting a target, an optotype detecting means for detecting the position of the optotype, a mask for presenting a part of the optotype in the screen so as to overlap the presented screen, and the mask. Mask means having moving mask drive means, mask detection means for detecting the position of the mask, and mask control for controlling the mask drive means based on the detection of the mask detection means and the signal of the target selection means. Means, and an optotype control means for controlling the drive means so as to move the optotype to be presented selected based on the detection of the optotype detection means and the signal of the optotype selection means to substantially the center of the screen. And having Eye test device.