JPH0361446B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a visual field measuring device in which an optotype is formed by a plurality of light emitting elements.

[Prior art]

Conventionally, a visual field measuring device is known that presents an optotype by sequentially lighting up a plurality of light emitting elements arranged on a visual field measuring surface. Only the target light emitting element corresponding to the presentation was lit, and the other light emitting elements were not lit at all.

On the other hand, visual field measurement is performed while presenting an optotype on a visual field measurement surface that is illuminated by a background illumination device and has a predetermined background brightness. Due to the difference in reflectance, the brightness of the non-lit light emitting elements illuminated by the background illumination device is lower than the brightness of other visual field measurement surfaces, resulting in a problem that a visual field with uniform brightness cannot be obtained.

[Purpose of the invention]

The present invention provides a visual field measurement device that lights up each light emitting element of the visual target that is not presented in accordance with the brightness of the visual field measurement surface when a plurality of light emitting elements with different luminous efficiencies are used as visual targets. With the goal.

A further object of the present invention is to provide a visual field measuring device that is arranged on a visual field measuring surface to form a matrix and causes a plurality of light emitting elements having different luminous efficiencies to emit light with uniform brightness.

[Structure of the invention]

The present invention has the following structural features to achieve the above object. That is, as shown in FIG. 1, the present invention includes a plurality of light-emitting elements A that form a matrix and are arranged as optotypes, and the light-emitting elements are turned on under predetermined optotype presentation conditions to create an optotype. In a visual field measuring device having an optotype presentation control means B for displaying an optotype, a background lighting for lighting an optotype that is not presented at a frequency higher than the critical fusion frequency and with the average luminance of each light emitting element being adjusted to the above luminance. It consists of means C.

The present invention further provides that the background lighting means C includes a data storage means D for storing lighting data for each of the light emitting elements according to the characteristics of the light emitting elements, and a data storage means D for storing lighting data for each of the light emitting elements according to the characteristics of the light emitting elements; and a background lighting control means E for lighting the light emitting elements of the optotype.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. The automatic perimetry device, as shown in Figure 2,
Housing 10, circular hole 12 for inserting the face of the person to be measured
A panel 14 attached to the front side of the housing 10 with
A recognition switch 15 to be operated, a forehead rest 16 and a chin rest 18 attached to the housing 10 to fix the eye to be measured in a predetermined position, and the housing 10
It consists of an operation display device 22 attached to a side wall 20 of. The lower side wall near the front of the panel 14 has a handle 24 for moving the forehead rest 16 and the chin rest 18 vertically and horizontally. Inside the housing 10, there are many LEDs throughout the inner surface to display visual targets.
A hemispherical dome 23 is built in, and the eye to be measured is positioned at the center of the hemispherical dome 23.

The operation display device 22 includes a TV monitor 30 and a light pen 32, a printer 31 located below the TV monitor 30, a control switch 34 located above the TV monitor 30, and a fixed vision monitoring telescope 36. The TV monitor 30 displays the type and target distribution of the optotypes presented on the inner surface of the hemispherical dome 23, as well as a plurality of operation commands to be described later. Operate the equipment.

The printer 31 prints the measurement results. In the fixation monitoring telescope 36, the eye to be measured is the hemispherical dome 2.
This system monitors from the front whether or not the subject is gazing at a fixation target placed at the center of the spherical surface of No. 3, and the anterior segment of the eye being measured is observed through an aperture located at substantially the same position as the fixation target. Monitor.

The operating instructions for this device are as follows.

(1) Selection of a measurement program, such as a screening program that measures the entire visual field in a screening manner, a meridional program that measures the meridian direction, etc., and is selected using the light pen 32 before starting the measurement.

(2) The brightness (intensity) of the presented optotype is selected using the light pen 32.

(3) Selection of the lighting time of the visual target to be presented. light pen 32
selected by.

(4) Selection of the time interval from one presentation of the presentation target to the next presentation. light pen 3
2.

(5) Start measurement program. Although it is operated by the light pen 32, it is also operated by the control switch 34 before starting the measurement.

(6) Interruption of measurement program. Although it is operated by a light pen 32, it is also operated by a control switch 34 during measurement.

(7) Restoration of measurement program. Although it is operated by the light pen 32, it is also operated by the control switch 34 during measurement interruption.

(8) Output of measurement results from a printer, etc. It is operated by a light pen 32.

Next, the configuration of this embodiment will be explained based on FIG. 3. The 1/0 interface 100 includes output signals from a light pen 32 and a control switch 34 that are operated by the measurer, and a recognition device that is operated by the person to be measured to indicate whether or not the visual target has been visually recognized. The output signal of the switch 15 is inputted, and the input signal is converted into a signal that can be easily processed by the internal device, and the measurement result is converted into a signal suitable for being printed by the printer 32.

The CPU 102 performs main control of this device, the details of which will be explained later using a flowchart. The presentation condition storage means 106 stores optotype presentation conditions that determine how the LEDs of the dome 23 are lit, that is, a plurality of combinations of lighting brightness (intensity), position, and lighting time. The response storage means 108 stores the response signal inputted via the subject's cognitive switch 15 in association with the optotype presentation condition at that time. Thereby, data regarding the visibility of the subject is obtained.

A GDC (Graphic Display Controller) 110 sends information about the LED array signal, the selected measurement program signal, the signal indicating the position of the lit LED, and the response signal to the TV monitor 30 to which it is input. It forms an image signal for displaying and outputs it to the video memory 112.
For example, this GDC110 has NEC (registered trademark)
μPD7220 is available. Timing control circuit 11
4 forms a suitable timing signal from the clock signal output from the clock oscillator 116;
GDC110, CPU102 and video memory 1
Output to 12.

The P/S converter 118 performs parallel-to-serial conversion on the parallel digital signal from the video memory 112 to form a video signal and outputs the video signal to the TV monitor 30.

The selector 120 is controlled by the output of the CPU 102 and enables either the first buffer 122 or the second buffer 124 to input the output to the matrix interface 126. The first buffer 122 is for displaying the optotype and outputs the presentation condition signal from the presentation condition storage means 106 to the matrix interface 126, and the second buffer 124 is for lighting at times other than displaying the optotype. It outputs an index lighting signal including an efficiency correction function from a correction data storage means 128, which will be described later, to the matrix interface 126.

As shown in FIG. 4, the matrix interface 126 lights up the optotype presentation conditions sequentially read out by the CPU 102 and the optotypes for which no optotype presentation is sequentially read out from the correction data storage means 128 in accordance with the background brightness. It is an interface for lighting a predetermined LED 200 under predetermined conditions based on correction data for
and a transistor array 204 having ports No. 21 to No. 40 and controlling the rows,
form a matrix. The LED matrix is
Matrix interface 126 No. 1 or
It is constructed by connecting the No. 40 port LED 200 as shown in FIG.

The address signal forming means 130 is the CPU 102
An address signal for reading out the correction data stored in the correction data storage means 128 is formed based on the timing signal received from the correction data storage means 128, and the address signal is outputted to the correction data storage means 128. The above address signal corresponds to the row/row of the table in the correction data storage means 128.
Specify the column line.

The correction data storage means 128 stores a large number of optotype LEDs 20 forming a matrix of columns and rows.
It stores correction data for correcting a luminous efficiency of 0, that is, a difference in brightness. The correction data is stored as a correction table as shown in FIG. That is, in the correction table, the line numbers of the matrix are arranged in the row direction, that is, the horizontal direction, the 1st to 20th columns are the column lines of the matrix, and the 21st to 40th columns are the row lines of the matrix. . On the other hand, the column direction, that is, the vertical direction, of the correction table represents the reading order, and 1 to 8 are the correction data in the first row of the matrix, 9 to 16, 17 to 24..., 153 to 24, etc.
160 are the second and third rows of the above matrix, respectively.
Rows..., the correction data of the 20th row. This correction data storage means 128 outputs correction data in response to an address signal formed by an address signal forming means 130, which will be described later, but the output is performed in one line for each column. When one line is taken, it has a so-called latch function in which the previous data continues to be output as long as the output does not change when the same data is being read.

FIG. 5 shows a correction table stored in the correction data storage means 128. Assuming that the first correction data, that is, rows 1 to 8, have been read out in the correction table, the ports connected to the transistor array 20 during this time are Of the corresponding 21st to 40th columns, only the 21st column is all 1, and the 21st to 40th columns are all 0, so the 21st row, that is, No. 21 of the transistor array 204 constituting the matrix interface 126. connected to the port of
Only the LED 200 can be lit, and the first row of LEDs in the LED matrix will be corrected. On the other hand, looking at the first column of the correction table, the first to fifth rows are 1 and the sixth to eighth rows are 0.
Therefore, the matrix interface 126
LED 200 in the first column and first row controlled by
As shown in FIG. 6, during the reading periods 1 to 8, the light is turned on during the periods 1 to 5. Looking at the second column of the correction table, the first to sixth rows are 1
Since the 7th to 8th rows are 0, the LED 200 in the 1st row and 2nd column controlled by the matrix interface 126 lights up only for periods 1 to 6 during periods 1 to 8. . Therefore, the LED 200 in the first row and second column is
This means that the LED remains lit for a period of 1 out of the periods 1 to 8, but this is due to the fact that the second
This is to compensate for the fact that the luminous efficiency of the LEDs in the column is lower than the luminous efficiency of the LEDs in the first row and second column. This readout is continued until the last correction data in the 20th row, and is repeated at a frequency equal to or higher than the critical fusion frequency with visual target presentation in between, as will be described later. Therefore, for the person being measured, it is perceived as uniform brightness as shown in the Talbot-Plateau law. On the other hand, the correction data is determined according to the luminous efficiency of each light emitting element 200 so that the subject feels the same background brightness as the background illumination. As explained above, the correction data of this configuration is read out sequentially from the first row of the LED matrix, that is, the correction data group of the LEDs 200 from the first column to the 20th column in chronological order. will be read out. In this case, a huge amount of correction data will be read out from the correction data storage means 128 at high speed, but it will not be read out directly by the CPU 102, but will be read out using timing determined by the CPU 102, and the address signal itself will be read out from the correction data storage means 128. Since the address signal forming means 130 forms,
No load is placed on the CPU 102.

Background lighting device 132 is 1/0 interface 1
The inner surface of the hemispherical dome 23 is illuminated with a predetermined brightness by the output of 0.00.

Next, the operation of the visual field measuring device of this embodiment will be explained with reference to FIG. When the measurement is started, the selector 120 selects the first buffer 122 based on the output from the CPU 102, and on the other hand, the index presentation condition signal read out according to the command from the CPU 102 is input to the matrix interface 126, and the visual target is displayed according to the condition. A presentation is made.

Subsequently, the selector 120 selects the second buffer 124 based on the output from the CPU 102;
The address signal forming means 128 forms an address signal based on the output of the CPU 102 and outputs it to the correction data storage means 130. In response to the input of the address signal of the correction data storage means 130, the LED is turned on to the same brightness as the background illumination via the matrix interface 126.

Next, it is determined whether all the correction data in the correction data storage means 128 has been read and executed, and if NO, the process proceeds to the step of forming the address signal. If it is determined that all the reading and execution of the correction data has been completed, then it is determined whether or not the measurement has been completed, and if the measurement has not yet been completed, the step of selecting the first buffer is performed. Proceed to. This operation stops when it is determined that the measurement is complete. The above routine is performed at the so-called critical fusion frequency of Fritsker, at which humans do not feel calm, in order to make the subject feel as if the display of the index and the illumination of the background compensation are being performed in parallel without making the subject feel the flickering of the background illumination. repeated at a rate corresponding to a higher frequency.

〔Effect of the invention〕

According to the present invention, in a perimetry device that uses a plurality of light emitting elements as visual targets, the light emitting elements that are not displaying visual targets are lit at a frequency equal to or higher than the critical fusion frequency with an average luminance equal to that of the background surface. For the measurer, the situation is the same as that of a background surface illuminated with uniform brightness, and a visual field measurement device that can perform more accurate visual field measurements can be obtained. Furthermore, if the efficiency, etc. of the light-emitting elements that make up the optotype of the visual field measuring device are different, the difference in efficiency of the light-emitting elements can be compensated for by correcting the lighting time according to the characteristics of the light-emitting elements. I can do it.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the entire structure of the present invention, Fig. 2 is a perspective view of a visual field measuring device according to an embodiment of the present invention, Fig. 3 is a block diagram of the structure of the embodiment, and Fig. 4 is a light emitting element. 5 is an explanatory diagram of the correction data, FIG. 6 is a waveform diagram showing the lighting timing of the light emitting element according to the correction data shown in FIG. 5, and FIG. 7 is a flowchart showing the operation of the embodiment. It is a diagram. A...Light emitting element, B...Optotype presentation control means, C
...Background lighting means, D...Data storage means, 10
...Housing, 15...Cognition switch, 23...
... Hemisphere dome, 102 ... CPU, 106 ... Presentation condition storage means, 108 ... Response storage means, 11
0...GDC, 118...P/S converter, 112
...Video memory, 122...1st buffer,
124...Second buffer, 126...Matrix interface, 128...Correction data storage means, 130...Address signal forming means.

Claims (1)

[Claims] 1. A plurality of light emitting elements forming a matrix are arranged as optotypes on a background surface with a predetermined brightness, and the light emitting elements are turned on under predetermined optotype presentation conditions to present the optotype. In a visual field measuring device having an optotype presentation control means, the light emitting elements of the optotypes for which no optotypes are presented are turned on at a frequency equal to or higher than the critical fusion frequency so that the time average luminance of each light emitting element matches the background surface luminance. A visual field measuring device comprising: , and background lighting means. 2. In the visual field measuring device according to claim 1, the background lighting means includes a data storage means for storing lighting data according to the characteristics of each light emitting element, and a data storage means for reading out the lighting data from the data storage means. 1. A visual field measuring device comprising: background lighting control means for lighting a light emitting element of an optotype that is not presented. 3. In the visual field measuring device according to claim 2, the lighting data is formed by a lighting data group indicating the lighting state of each light emitting element corresponding to the lighting time, and the background lighting means A visual field measuring device characterized by reading data in chronological order.