JPS58112527A - Sight deciding apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a visual acuity determining device 7' in which the display position in the direction of the Landolt annular gap can be arbitrarily changed by rotating a sign plate.

The so-called Landolt annulation is known as a visual acuity determining device in which a part of the inner product is cut out and the direction of the gap is identified.When using this Landolt at, the state of visual acuity Mt- can be determined without being influenced by memory. Therefore, it is necessary to make the display order of the Landolt annulation in the gap direction irregular to eliminate the influence of memory. As an attempt,
During the Landolt ring formation, program several ways of display order in one direction and follow the program / Mr. Dort's destruction tl
! Next, a device was developed that rotates the 21st direction and switches the display position in the direction of the gap. However, as long as the program is assembled, the program follows certain rules, so it is impossible to completely eliminate the display order from being memorized.

The present invention solves the above-mentioned problems, and uses audio signals or melody signals from audio equipment such as radios, televisions, tapes, and melody devices to provide Landolt's lIK rotational feed, is changed irregularly to avoid artificial intervention in the display order in the gap direction.

An embodiment of the present invention will be described below with reference to the drawings. @1
In Figures (A) and (B), a sign board 2 depicting the Landolt Ring Formation 1 is assembled into a circular housing 5, and is passed through a window 5a1 of the housing S to provide an external view of Mr. Landolt]11't-. Let it happen. The Landolt ring formation 1t - the surrounding rim 55 of the housing S
bIC is given a number indicating the display direction of the gap 1 m of the Landolt ring formation 1. Reference numeral 4 denotes a motor that rotates two signboards. Further, 5 is a fluorescent light for transmitted illumination.

In Figure 1 (B), C is a control unit of the visual acuity determination device, the details of which are shown in the block diagram of Figure 2.

That is, 6 is a melody generating section consisting of a tape, a melody element, or other audio equipment, and the output melody signal is amplitude-limited by a Shemit circuit 7, and a waveform having an amplitude exceeding a set value is converted into a square wave. Only the square waves generated within the set time pass through the gate 8 and are input to the first step counter 9, and the step counter 9 increments by that number and then stops. A mechanism for opening the gate 8 for a set time consists of an interval timer 10 and a mono-multivibrator 11. That is, in FIG. 3, the interval timer 10 outputs a signal at every time t, and the output causes the monomarteno (ibrator 11) to operate and output a gate signal to the gate 8. (
The gate is opened for t*>t*) and the square wave generated within that time is input to the step counter 9.

The step counter 9 increments the step at a time of 11 yen, and continues to increment within the time ('r's) to maintain the friend step state.

In addition, in the example, the Landolt ring formation 1 illustrated on the signboard 2
An example is shown in which the display direction of FJIJ1 is set to 8 messages P-P. In the case of the embodiment, eight grooves t are formed at equal intervals on the outer periphery of the sign board 2, corresponding to the number of display positions.
1 to t are provided. On the other hand, a microswitch 12 is installed close to the ** board 2, and the contacts of the microswitch 12 are connected to the second step counter 15.

14 is a coincidence detection circuit for detecting coincidence of the number of steps of the first and second step counters 9.1S, and a relay 15km! is connected to the output side of the coincidence Yokota circuit 14. Then, when the number of steps of both counters 9.15 match, the relay 15 is activated by a matching signal. Normally closed contact 1 of relay 15
5-1 is connected to the power supply circuit of the motor 4 and the wiring of the speaker 16.

Next, the visual acuity determination device according to the present invention performs a runt.

The operation when switching the gap direction of Ruto's Hawk will be explained.

#ks In the diagram, if the melody signal at the output time jsPi of the monomartenometer 11 has the waveform shown in (C), this signal is converted into a square wave by the Siemite circuit 7 and is output as the output of the gate 8 as shown in (d). becomes a square wave of
The step counter 9 advances by 6 steps and then stops.

On the other hand, the lIw& plate 2 is driven by the motor 4 and rotates in the direction of the hour hand. Due to the rotation of the sign board 2, the contact points of the microswitch 12 fall sequentially to #jt to #t of the sign board 2, and then ride on the arc-shaped outer periphery of the sign board 2, thereby causing the microswitch 12 to become O.
N, OFF L, Norkurus Signal Association Step Cow/Re 1
Enter 3 to advance the number of steps. From the state shown in Figure 2, in the direction of time 1 (It acupuncture plate 2 rotations τ
When the rotation starts, the speaker 16 and 9
A melody is uttered. Further, the microswitches 12 are sequentially connected to the grooves 1□ to t.

It generates a pulse when it falls. On the other hand, since the counter 9 is incrementing by 6 steps, when the contact point of the microswitch 12 originates from mtl and falls to the 6th point, ie, t, both counters 9 and 13 (the number of D steps match) As a result, the -Ku detection circuit 14 outputs a signal from the -Ku detection circuit 14,
This signal operates the relay 15, opens the normally closed contact 15-1, and stops the motor 4. Therefore, in the sign board 2, the gap 1a of Landolt 11 stops the display position Pa'' in the same direction (see Fig. 1 (a)).Also, since the normally closed contact 15-1 of the relay 15 opens, The speaker 16 and the melody generating section 6 are connected, and the melody is transmitted through the speaker 16.
It stops flowing.

The above creation is performed within the time t1 that the mono multivibrator 11 outputs, and the next time (1□-Im
), the signboard 1 will stop and Mr. Landolt*i will be displayed. After that, when time t has elapsed, the interval timer 1o outputs a pulse, the mono-multivibrator 11 operates, the gate 8 opens, and a square wave is input to the step counter 9 in response to the melody signal. As a result, the numbers of steps on both counters 9 and 13 no longer match, and the contact point of the relay 15 is restored and the motor 4 is restarted.

On the other hand, as the motor 14 rotates, the circuit of the speaker 16 is configured and a melody is played. Then, when the steps of both counters 9.13 match based on the melody signal during the operating time t of the mono-multivibrator 11, the sign board 2 stops again and the display switching operation of the Landolt ring formation 1 is repeated.

As described above, the present invention converts an audio signal or melody signal from an audio device such as a radio, television, tape, or melody element into a square wave, and changes the display position of the Landolt ring by the number of square waves within a set time. The melody signal, which is the basis of the Landolt ring display switching, has no regularity, so completely irregular displays are possible.
Accurate visual acuity judgment can be made.

According to the present invention, it can be installed in schools, etc., and allows children and students to independently check their visual acuity using their body time, such as when going to school, leaving school, etc., and is effective in preventing pseudomyopia in children and students. This has the effect of making it possible to take appropriate countermeasures.

[Brief explanation of drawings]

FIG. 1(a) is a front view of the visual acuity determination device, FIG. 1(b) is a longitudinal sectional view, FIG. i@2 is a block diagram of the control unit, and t4S is a time chart. 1...Landolt ring 2...Sign plate 4...Motor 7...Shemitt circuit 9.13...Step counter 14...Concordance detection circuit 15...Relay % measurement applicant Co., Ltd. Sankosha

Claims (1)

[Claims] (1) In a visual acuity determination device that rotates the sign board and switches the display position in one direction, a Schmidt circuit that converts a melody signal into a square wave and the number of square waves within a set time are used. # to step forward and stop
! 1 step counter and the rotation of Landolt ring formation,
A step counter on the second leg that increments at each display position in the direction of the gap, a coincidence detection circuit that detects the coincidence of the number of steps in both step counters, and an output of the iron structure circuit that drives the sign board. A visual acuity determination device comprising a stopping mechanism.