JP2750512B2 - Eye test - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of arranging a plurality of visual acuity measuring targets in one screen and switching to a screen having another visual acuity measuring target. The present invention relates to a visual acuity inspection device capable of performing the above-mentioned. 2. Description of the Related Art A visual acuity chart,
Since many indices such as astigmatism charts and stereoscopic charts are required, it is economical to fit all of them in one screen.
This is practically impossible due to location constraints. In view of this, it is common to extract main optotypes and configure them as one screen, or to split the entire optotype and have a plurality of optotypes on the same screen. In these devices, a mechanism has been conceived that specifies what the subject should read from a plurality of optotypes in order to further smooth the response between the examiner and the subject. [0003] Conventionally, as means for specifying a target from among a plurality of targets, a lamp is arranged behind each of the targets, and a lamp to be presented is provided. Some lamps turn on a lamp corresponding to the combination. However, in this device, the target itself is not replaced, so the device becomes large, and the subject changes the target position,
There is a disadvantage that the target must be seen. There is also known a projection-type visual acuity inspection apparatus (chart projector) for projecting a target image on a screen, in which a rotary disk with a mask is superimposed on a rotary disk with a target. FIG. 10 is a schematic diagram of this device. The optotype unit 103 is switched by the rotation of the visual acuity table disk 101 about the rotation center 102. The mask plate disk behind the visual acuity table disk also rotates about 102 as the center of rotation, and the horizontal mask 104A overlaps the illustrated visual acuity value sequence. Next, when the horizontal mask is superimposed on the visual acuity value sequence thereabove, since the horizontal mask 104A is inclined, it is necessary to overlay another horizontal mask 104B. In order to superimpose the horizontal mask on each visual acuity value column in this way, a mask is required for each column. To present one character, a mask for each character is required. As described above, the projection type visual acuity inspection apparatus (chart projector) in which the rotating disk with the mask is superimposed on the rotating disk with the target has a circular arc in the moving direction of the disk. Since the mask cannot be applied at the center of the screen, and the number of required masks is extremely large, the apparatus becomes complicated. SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, an object of the present invention is to provide a visual acuity inspection apparatus that can mask a target at the center of the screen and minimize the number of masks. According to the present invention, in order to achieve the above object, a large number of optotype screens composed of a plurality of optotypes are provided.
The target screen is switched by the electric drive means.
Presents the desired optotype on the fixed optotype presenting surface to precisely examine the eye
In vision testing apparatus for testing a target selection means for selecting one or rows of <br/> target within target entire screen or target screen to be presented to the examinee, the optotype Attached to each screen
The detected mark is detected and one
Optotype detection means for recognizing the position of the optotype or column optotype;
Mask means having a mask superimposed on a screen for presenting a part of the target screen, and mask driving means for moving the mask; mask detecting means for detecting the position of the mask; A mask control means for controlling the mask driving means based on the detection of the means and the signal of the optotype selecting means, and an optotype screen selected based on the detection of the optotype detecting means and the signal of the optotype selecting means. When the target screen
Place one body or row in the optotype screen on the optotype presenting surface
When one of the optotypes is selected, one or a row of optotypes is selected
A visual target control means for controlling the driving means so as to move at substantially the center on the target presentation surface . Hereinafter, the present invention will be described with reference to the accompanying drawings. FIG. 1 is an external view of a main body of a visual acuity inspection apparatus according to a first embodiment of the present invention, in which optotypes other than one horizontal line at the center of a screen are masked. FIG. 2 is an external view of the apparatus when a mask roll film 4 for specifying a target to be read by a subject from a plurality of targets in one screen is not used. Reference numeral 1 denotes a housing of the apparatus, 2 denotes a visual acuity roll film to be presented to a subject, and 3 denotes a light receiving unit for a remote controller for switching an optotype by a remote control. The hatched portion in FIG. 1 indicates the 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 'of FIG.
FIG. 3 is a sectional view taken along the line BB ′ in FIG. 2. Eyesight table upper row
A visual acuity roll film 2 on which a visual acuity test target is drawn is wound between a roller 5 and a visual acuity lower roller 8, and the visual acuity upper motor 16 and the visual acuity lower motor. At 17, the visual acuity table upper roller 5 and the visual acuity table lower roller 8 are rotated to switch the screen. Reference numeral 14A denotes a photoelectric switch for detecting the initial position of the visual acuity roll film disposed on the left side of the screen, and a photoelectric switch for detecting the target position of the same shape (31 in FIG. 6) is provided on the right side of the screen.
A). Reference numeral 13 denotes a lamp for illuminating the eyesight roll film 2 from the back, and is turned on by a relay (51 in FIG. 8). Reference numerals 9 and 12 denote an upper roller for masking and a lower roller for masking for masking a target other than a specific target from a plurality of targets displayed on the screen, and a roll film for mask. 4, the upper motor 18 for the mask, the lower motor 24 for the mask, the pulleys 21, 23, 2
The screen is switched by rotating the upper roller 9 for the mask and the lower roller 12 for the mask with the belts 9 and 27 and the belts 22 and 28. Reference numeral 14B denotes a photoelectric switch for detecting the initial position of the mask film disposed on the left side of the screen, and a photoelectric switch 31B for position detection having the same shape on the right side of the screen. FIGS. 5 and 6 are explanatory views of a position detecting mechanism for displaying a desired film on a screen. First, a mark indicating the start position is written on the visual acuity roll film 2 and the roll film 4 for the mask. In this embodiment, black belt-like marks 30A, 3
Since there is 0B, the position where light is blocked by the film initial position detecting photoelectric switches 14A and 14B is detected. Next, marks 32A and 32B are displayed on the visual acuity roll film 2 and the mask roll film 4 to indicate displacement from the start position for each screen. The marks are detected by the photoelectric switches 31A and 31B for position detection, 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 mere opening as long as the intensity can be maintained. 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 them is not important, they are reversed for explanation. . The operation of the above embodiment will be described below. First, an operation for presenting a visual acuity test target will be described. When the power is turned on, the visual acuity table upper motor 16 is allowed to rotate freely without applying a voltage, and the visual acuity table lower motor 17 is rotated by applying a voltage, and the visual acuity table roll film 2 is rotated. Rewinds to the upper roller 8 of the eyesight table, and the photoelectric switch 14A for detecting the initial position of the eyesight table film.
When the mark 30 is detected, the photoelectric switch 14A is turned off, and the visual acuity roll film 2 is set to the start position. When the film is stopped, the voltage applied to the upper and lower pulse motors of the visual acuity table is reduced below the rating by the voltage switching circuit 48, and the upper and lower rollers of the visual acuity table are held in a state where no heat is generated. Prevents film from sagging. An infrared signal emitted from a remote controller 46 from the outside of the apparatus is transmitted to a light receiving preamplifier 4 mounted on the housing 1.
5. In the detection circuit 44, a signal component digitized from the infrared modulated light is extracted, and the input / output circuit 43, the CPU 40,
A command signal for presenting a target corresponding to the signal component is generated by the RAM 41 and the ROM 42. The command signal passes through the input / output circuit 43, and maximizes the voltage in the motor driving circuit 47 and the voltage switching circuit 48.
The data 16 is driven. At this time, the lower eyesight motor 17
Since no voltage is applied to the lower winding roller 8, the lower winding roller 8 can rotate freely, so that high-speed winding can be performed despite the small torque of the driving pulse motor. The feed position of the visual acuity roll film 2 is shown in FIG.
The mark 32A for detecting the film position is connected to the photoelectric switch 3
1A, it detects the mark position immediately before it is presented, and starts deceleration for stopping. When the upper motor of the visual acuity table on the driving side is decelerated, the lower take-up roller 8 rotates freely and unnecessarily feeds the film by the inertia moment. A weak braking torque is applied by intermittently applying a pulsed voltage. As the speed decreases, the period of the intermittently applied voltage is shortened and stopped. By the above operation, the film can be prevented from being slackened from deceleration to stop, the tensile force applied to the film can be reduced, and the stop position accuracy can be increased. Next, the operation of the mask roll film will be described. Driving and molding of roll film 2 for mask
The control method of the data table is basically the same as that of the eye chart roll film. That is, when the power is turned on, the lower motor 24 for the mask rotates, and the roll film 4 for the mask is rewound to the lower roller 12 for the mask. And the mask low film 4 is set at the start position. FIG. 7 shows the moving direction of the low film 4 for a mask. A light receiving preamplifier 45, a detection circuit 44, an input / output circuit 43, an input / output circuit 43, a CPU 40,
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 is sent to the motor drive circuit 5 via the input / output circuit 43.
2. The voltage is maximized by the voltage switching circuit 55 to drive the upper pulse motor 18 for the mask. At this time, no voltage is applied to the mask lower pulse motor 24 as in the case of the eyesight table upper motor. The feed position of the raw film 4 for the mask can be detected by the photoelectric switch 31B at the mark 32B for detecting the film position in FIG. 6, and the mark position immediately before to be presented is detected and stopped. Enter the deceleration. When the upper motor for the drive side mask is decelerated, the lower take-up roller 1
Since the film No. 2 unnecessarily feeds the film, a weak braking torque is applied by intermittently applying a pulse-like voltage as in the case of the visual acuity table upper pulse motor. As the speed decreases, the period of the voltage applied intermittently is shortened,
Stop. Next, the operation of presenting a specific target sequence on the same screen will be described. In FIG. 7, after the visual acuity roll film 2 is moved to present a predetermined visual acuity chart screen, the roll film 4 for a mask is moved to arrange the horizontal mask at the center of the screen. Thereby, it is possible to present only the target 2b in the horizontal row shown in the figure. Next, when presenting one row of targets 2a, the visual acuity table film 2 is moved by a target column switching switch (not shown) on the remote controller 46 while the horizontal mask is fixed, and 2a is presented at the center of the screen. Similarly, when presenting a row of optotypes 2c, it is possible to move 2c to the center of the screen while keeping the horizontal mask fixed. The first
In this embodiment, it is possible to present all the optotypes in one horizontal line at the center of the screen with one horizontal mask. FIG. 9 is a diagram for explaining the second embodiment.
The visual acuity roll film 2 and the one character presenting mask 4b on the mask roll film 4 can be moved in directions orthogonal to each other. The driving method of each film is the same as that in the first embodiment, and a description thereof is omitted. One character presentation mask 4b can be moved in the left-right direction in the figure, and can be moved to a position that matches the target 2i to present only 2i. Similarly, 2h, 2j, 2
Presentation of k is also possible. Further, by moving the roll film for mask in the left-right direction while moving the visual acuity table film 2d to the position 2h in the figure, 2d to 2g is obtained.
Can be presented. Similarly, 2e to 2o can be presented. As described above, in the second embodiment, one character mask 1
One character can be presented to all of the targets 2d to 2o just by preparing one. In addition, if a vertical mask is used, all the targets can be presented in one vertical line with one vertical mask. Although the first and second embodiments use a film, the same effect can be obtained by moving a plate-shaped visual acuity table and a mask. As described above, according to the present invention,
The subject was able to see the optotype at approximately the center of the screen without moving his gaze. For example, when presenting a single line of optotypes to a subject, it is possible to present the optotypes by moving the optotypes while the mask is fixed at the center, so that the number of masks can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a first embodiment of the present invention in which a horizontal mask is used to indicate a target to be read by a subject from a plurality of targets in one screen. It is an external view of the visual acuity inspection device main body. FIG. 2 is an external view of a visual acuity inspection apparatus main body when a mask is not used. FIG. 3 is a sectional view taken along the line AA ′ of FIG. 2; FIG. 4 is a sectional view taken along the line BB ′ of FIG. 2; FIG. 5 is an explanatory diagram of a position detection mechanism for displaying a desired film on a screen. FIG. 6 is an explanatory diagram of a position detection mechanism for displaying a desired film on a screen. FIG. 7 is a diagram for explaining an operation when a horizontal mask is used. FIG. 8 is a block diagram of a visual acuity table and a drive unit of 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. [Description of Signs] 2 Visual acuity roll film 4 Roll films 14 and 31 for mask Photoelectric switch 16 Upper visual acuity (pulse) motor 17 Lower visual acuity (pulse) motor 18 Upper mask (pulse) Motor 24 Mask lower (pulse) lower motor 30 Film initial position mark 40 CPU

   ────────────────────────────────────────────────── ─── Continuation of front page    (56) References Japanese Utility Model Showa 59-38904 (JP, U)                 New Ophthalmology Course (Japanese Eye Hygiene Association, Sho               38.3.15 issued)                 "TOKO CHART PROJE               Handling of CTOR Toko Eye Chart Projector               Manual                 Eyeglass General Magazine "Eyeglass" (Eyeglass Optics)               Publishing Co., Ltd., published 59.3.15)

Claims (1)

(57) [Claims] Having many optotype screens composed of multiple optotypes,
The target screen is switched by the electric drive means and the predetermined target
Present the desired target on the presentation surface and inspect the eye to be inspected precisely.
In order for vision testing apparatus, seen to be presented to the examinee
Optotype selecting means for selecting the entire optotype screen or one or a row of optotypes in the optotype screen, and a mark attached to each optotype screen.
And a single target in a target screen.
A target detecting means for recognizing the position of a column optotype, target screen and weight
Mask means having a mask for folding and presenting a part of an optotype of the optotype screen, and mask driving means for moving the mask; mask detecting means for detecting the position of the mask; A mask control unit that controls the mask driving unit based on a signal from the detection and the optotype selection unit; and a case where an optotype screen is selected based on the detection of the optotype detection unit and a signal from the optotype selection unit. Is in front of the entire optotype screen
One or a row of targets in the target screen on the target display surface
When is selected, one or a row of optotypes is presented
An eyesight control device, comprising: a target control unit that controls the driving unit so as to move at substantially the center on the surface .