JP7624352B2 - Visual target presentation device - Google Patents

Description

The present invention relates to a visual target presentation device.

There is known an optotype presentation device that presents visual acuity test optotypes to the subject's eye in order to test the visual function of the subject's eye. Conventionally, such optotype presentation devices have included devices that present optotypes printed on paper or a panel by illuminating them with a light source such as a tungsten lamp, halogen lamp, fluorescent lamp, or LED, or devices that present the optotype by projecting it onto a screen using a light source, but recently devices that display the optotype on an electronic display device such as a liquid crystal device illuminated by a backlight have been widely used. (See, for example, Patent Document 1.)

Generally, these optotypes are displayed as black optotypes on a white background, but the background of optotypes that use tungsten or halogen lamps as light sources has a low color temperature and appears reddish white. In contrast, the background of electronic display devices often has a high color temperature and appears bluish white. Also, fluorescent lights come in multiple colors, ranging from reddish incandescent light to bluish daylight light, and the color of the illuminated background varies. For this reason, when multiple types of optotype presentation devices with different light sources are used together, the color of the background will differ for each device, which may cause the subject to feel uncomfortable.

Patent Document 1 discloses that in order to suppress the variation in the brightness of the white background for each device, the amount of light of the backlight that illuminates the background of the display is controlled according to a predetermined adjustment value that is preset for each device, and the brightness of the background is switched. However, the variation in the color of the white background cannot be eliminated by simply controlling the amount of light of the backlight. In addition, in the case of an electronic display device, the color can be changed by lowering the brightness of any of the RGB pixels, but simply lowering the brightness of a pixel makes the background dark, which affects the appearance and the results of a visual acuity test. In order to change the color without darkening the background, it is necessary to consider the balance of the three RGB colors, so it is not easy to reproduce the desired color.

JP 2008-206675 A

The present invention was made in response to the above problem, and aims to provide an optotype presentation device that can easily change the background color of an optotype to a desired color.

To achieve the above object, the optotype presentation device of the present invention includes an optotype display unit that presents an optotype for testing eye characteristics to the subject's eye, an input unit that accepts designation of color information related to the color of the background on which the optotype is displayed, and a background color setting unit that sets the background color of the optotype based on the color information accepted by the input unit.

With a visual target presentation device configured in this way, the background color of the visual target can be easily set to a desired color.

1 is a schematic diagram showing an overall configuration of a visual target presentation device according to a first embodiment. FIG. 3 is a schematic diagram of a background and an optotype displayed in an image display area of the optotype display unit. FIG. 1A and 1B are schematic diagrams of an operation unit, in which (1) shows a schematic diagram of the operation unit of a first embodiment, and (2) shows a schematic diagram of the operation unit of a modified example. 1A and 1B are explanatory diagrams of tables in which color information is associated with the gradation of each RGB pixel for each color information, where (1) shows the table configuration of the conversion table and (2) shows the table configuration of the gradation value table. FIG. 13 is a schematic diagram showing a configuration of a visual target presentation device according to a second embodiment.

First Embodiment
Hereinafter, a first embodiment of an optotype presentation device of the present invention will be described with reference to the drawings. First, the configuration of an optotype presentation device 10 according to the first embodiment will be described with reference to Figs.

The optotype presentation device 10 according to the first embodiment is a device that displays an optotype for testing the eye characteristics of the subject's eye E on a white background and presents it to the subject's eye E, and the color of this background (background color) can be set according to the specifications of the user, such as the examiner.

Here, "setting the background color" means setting (changing) the hue of the white background color to a desired hue according to the user's specifications. "Hue" refers to the degree of color shading and shifting, and subtle shades. For example, "white" can appear to have different hues depending on the mixture of light and colors, such as "reddish white" or "bluish white."

For this reason, in devices capable of presenting a visual target to the subject's eye E, such as visual target presentation devices and eye examination devices having a visual target presentation means, the white color of the visual target may vary from model to model depending on the type of light source, such as a backlight, that illuminates the visual target, or the light, such as fluorescent lights, that illuminate the room. When different models of visual target presentation devices are mixed, this may cause the subject to feel uncomfortable. To solve this problem, the visual target presentation device 10 of the first embodiment allows the background color to be set to a desired hue.

As shown in FIG. 1, the optotype presentation device 10 according to the first embodiment includes a main body 1 having a housing 11, an optotype presentation optical system 12, a memory 13 as a storage unit, and a control unit 14 as a background color setting unit, an operation unit 15 as an input unit, and an eye examination table 16 on which the main body 1 is placed.

The main body 1 has a housing 11 with a built-in visual target presentation optical system 12, memory 13, control unit 14, etc., and is placed on an eye examination table 16, etc. A window 11a is provided on the front side (subject P side) of the housing 11 so that the subject P can view the visual target.

The visual target presentation optical system 12 includes a visual target display unit 12a, a first reflecting mirror 12b, a lens 12c, and a second reflecting mirror 12d.

In the first embodiment, the optotype display unit 12a is a liquid crystal display (LCD) device that displays a predetermined optotype on a white background illuminated by a backlight (light source). In addition to a liquid crystal display, this optotype display unit 12a can be suitably an organic electroluminescent display (OELD), but is not limited to these.

The optotype is not particularly limited as long as it is used in eye examinations, and suitable examples include Landolt rings, Snellen optotypes, E charts, etc. In addition, the optotype can be a variety of optotypes, such as optotypes consisting of characters such as hiragana or katakana, pictures of animals or fingers, specific figures for binocular vision function eye examinations such as a cross optotype, or optotypes consisting of landscape paintings or landscape photographs, etc.

The optotype presenting optical system 12 reflects the light beam from the optotype display unit 12a toward the lens 12c by the first reflecting mirror 12b, and refracts the light by the lens 12c to form a virtual image i of the optotype at a distance from the subject's eye E. The light beam transmitted through the lens 12c is then reflected by the second reflecting mirror 12d to present the optotype at a distance in front of the subject's eye E. The subject P visually recognizes the optotype through a window 11a provided in the housing 11.

The optotype presentation device 10 may also include an eye examination unit (refractor head) 17 for correcting the visual function of the subject's eye E, between the window 11a and the subject's eye E, as shown by the virtual line in FIG. 1. The eye examination unit 17 incorporates multiple optical elements such as polarizing filters, spherical lenses, cylindrical lenses, and prisms, and these optical elements can be selectively positioned in the eye examination windows provided corresponding to the left and right subjects' eyes E. The subject P can visually recognize the optotype through the window 11a with the visual function of the subject's eye E corrected by the eye examination unit 17.

The optotype display unit 12a, which is made up of an electronic display device, has a plurality of pixels including three colors, R (red), G (green), and B (blue), and has a gradation change function that can change the gradation (gradation value) of each color pixel. The optotype display unit 12a can change the color of the optotype by changing the gradation of each color pixel under the control of the control unit 14. Note that the pixel colors are not limited to the three colors of RGB, and may be four or more colors.

The term "gradation" refers to the number of stages indicating the density or brightness of a color in stages, and in the first embodiment, it is set to 8-bit 256 gradations (0 to 255), but is not limited thereto. In the optotype display unit 12a, the initial value (default) of the gradation of the background 102 in the image display area 100 shown in FIG. 2 is set to white with an optimal luminance value (e.g., 200 Cd/m ² ), and the gradation of each pixel of R, G, and B is set to the same value. For example, the gradation value is set to 98 gradations (R: 98, G: 98, B: 98) out of a maximum value of 255 gradations. Then, based on the color information input from the operation unit 15, the control unit 14 calculates the gradation of each pixel of RGB, and based on the calculated gradation, the optotype display unit 12a changes the gradation of each pixel of RGB of the background 102. As a result, the background color is set to a desired white color.

On the other hand, the gradation of the target region 101 that forms the target is set to 0 gradation (R:0, G:0, B:0), which is the darkest (lowest transmittance) state (black color), but by changing the gradation of the target region 101, it is possible to change the contrast of the target against the background 102. This makes it possible to perform a contrast test or the like that measures the contrast sensitivity of the subject's eye E.

The memory 13 is composed of storage media such as RAM, ROM, semiconductor memory, and a hard disk drive. The memory 13 stores in advance programs and various information for the control unit 14 to execute processing, as well as various information obtained by the processing of the control unit 14. The memory 13 also stores a table in which, for each piece of color information related to the background color, this color information is associated with the gradation of each RGB pixel color.

Figure 4 shows an example of a table used in this embodiment. (1) in Figure 4 is an example of a conversion table T1, which is a table in which correction values are set to convert the gradation of each pixel of color from the initial value (default) to a value corresponding to the color information. As shown in this conversion table T1, in the first embodiment, color temperature is used as color information. Conversion table T1 has seven color temperatures in increments of 1000K from 2000K to 8000K, and correction values for the luminance value of each color of RGB set for each color temperature. These correction values are set with consideration given to the balance of each pixel of RGB so that the apparent brightness (luminance) of the background 102 does not change even if the color temperature is changed to any of the seven levels.

In other words, if you just want to change the color, you can achieve this by changing the gradation values of each R, G, and B pixel individually. For example, if you want a reddish white background color, you can simply lower the gradation values of G and B to (R: 98, G: 98, B: 98) as described above, such as (R: 98, G: 95, B: 90). However, it is difficult to control the color along the approximate blackbody radiation locus, and the brightness of the background may decrease, which may affect the inspection results. For this reason, it is necessary to adjust each gradation value while taking into account the balance of RGB, and to change the color of the background along the approximate blackbody radiation locus without decreasing the apparent brightness (luminance). To achieve this, in this embodiment, the user sets a correction value for the gradation value for each RGB color.

Figure 4 (2) shows the gradation values obtained by multiplying the initial value (default) of gradation 98 by the correction values of the pixels of each color of RGB obtained from the conversion table T1 in (1) for each color temperature. For example, when the color temperature is 2000K, the correction values R = 2.595, G = 0.675, and B = 0.112 are selected from the conversion table T1 as correction values. By multiplying these correction values by the initial values of the gradation values R = 98, G = 98, and B = 98, the corrected gradation values R = 254, G = 66, and B = 11 are obtained. The initial values (default) of the gradation values of each pixel of RGB are set to values adjusted to the optimal gradation out of 256 gradations so that the electronic display device has an appropriate brightness, taking into account the individual differences of the electronic display device, which is the optotype display unit 12a, and the optotype presentation optical system 12. Also, if the initial value has been determined, the result of the multiplication can be stored as a table, as shown in FIG. 4 (2), and the gradation value corresponding to the set color temperature can be read out directly.

The correction values in conversion table T1 are not limited to the values shown in FIG. 4, but can be set to values based on the spectral characteristic values according to the type of electronic display device, or values based on the spectral characteristic values of individual electronic display devices.

The color temperature and the correction value of each color pixel in the conversion table T1 may be stored unalterably in the memory 13 at the time of manufacture, etc., or may be stored changeably by a user, maintenance person, etc. from the operation unit 15, etc. Furthermore, each value in the gradation value table T2 may also be stored unalterably in the memory 13, or may be stored changeably. If it is changeable, for example, when a user, etc. changes the initial value of the gradation value, the control unit 14 can be configured to recalculate the luminance of each color pixel for each color temperature (or for the color temperature selected by the operation unit 15) based on the changed initial value and the correction value of the conversion table, and store it in the gradation value table T2.

The control unit 14 is composed of a microprocessor such as a CPU. The control unit 14 controls the operation of the entire optotype presentation device 10 according to signals such as operation instructions from the operation unit 15, and also functions as a display control unit for the optotype on the optotype display unit 12a, a drive control unit for the drive mechanism of the first reflection mirror 12b, a background color setting unit that sets (changes) the background color of the optotype display unit 12a, etc.

The control unit 14, which serves as a background color setting unit, acquires the color temperature from the operation unit 15, searches the table (tone value table T2) stored in the memory 13 based on the acquired color temperature, and acquires the corrected gradation value of each pixel of RGB color corresponding to the color temperature. Then, by controlling the optotype display unit 12a based on the acquired gradation value, the background 102 is displayed in the image display area 100 of the optotype display unit 12a in a background color adjusted to a color corresponding to the selected color temperature.

The operation unit 15 is a user interface operated by the examiner, who is the user, and functions as an input unit for inputting information and operation instructions. In this embodiment, the operation unit 15 is composed of a remote controller that can be operated remotely by the user from a location away from the optotype presentation device 10. The information and operation instructions input via the operation unit 15 are converted into signals and input to the control unit 14.

The operation unit 15 is not limited to a remote controller, and may include, instead of or in addition to a remote controller, buttons, keys, and control levers provided on the housing 11, and operation devices (mouse, keyboard, track pad, buttons, touch panel, etc.) of a personal computer or mobile terminal capable of communicating with the control unit 14. The operation unit 15 may also include a processor and computer program for performing operations and inputs based on voice.

A schematic diagram of the operation unit 15 of this embodiment is shown in FIG. 3 (1). As shown in this figure, the operation unit 15 has a display unit 15a on which input information and the like are displayed, various operation buttons 15b for inputting various information and operation instructions, a color selection button 15c for selecting a color temperature as color information, and a color display unit 15d on which the selected color temperature is displayed. The display unit 15a and the color display unit 15d are made of electronic display devices such as LEDs. The color selection button 15c has a button for increasing the color temperature and a button for decreasing the color temperature, and each time these buttons are pressed, the color temperature is switched to a higher or lower value and is displayed digitally on the color display unit 15d. A signal corresponding to the selected color temperature is input from the operation unit 15 to the control unit 14. This input may be performed automatically when a predetermined time (several seconds) has elapsed after the color temperature is selected, or may be performed when a decision button is provided separately from the color selection button 15c and the decision button is pressed.

The color display unit 15d is not limited to an electronic display device, and may be configured such that a member on which numbers are printed is mechanically switched in response to the operation of the color selection button 15c. In addition, in this embodiment, the color temperature is configured to be selectable in increments of 1000K from 2000K to 8000K, but this is not limited thereto, and the color temperature may be selected with finer numerical values such as 1K, 10K, 50K, 100K, ... In this case, the user or the like sets the values of the conversion table T1 and the gradation value table T2 for each selectable color temperature. The color display unit 15d may be configured to be displayed on the display unit 15a, and the color selection button 15c may use a part of the various operation buttons 15b. In this case, when the user or the like switches the mode selection, the contents of the color display unit 15d are displayed on the display unit 15a, and the functions of some of the various operation buttons 15b function as the color selection button 15c.

The operation (example of use) of the optotype presentation device 10 according to the first embodiment configured as described above will be described below. In the optotype presentation device 10 according to the first embodiment, to set the background color of the background 102 on which the optotype is displayed to a desired color, the examiner first operates the color selection button 15c of the operation unit 15 to select the desired color temperature.

For example, since the optotype presentation device 10 of this embodiment is equipped with an optotype display unit 12a consisting of an LCD or the like, an LED or the like is used for the backlight, and the background color of the image display area 100 has a high color temperature and appears bluish-white. In contrast, an optotype presentation device that illuminates the optotype with a light source consisting of a tungsten lamp, halogen lamp, or the like has a low color temperature of the light source, and therefore the background color appears reddish. Also, even if an electronic display device is used as the optotype display unit 12a, the hue of the background color may differ if the type is different, such as an LED or an OELD, or if the same type is made by a different manufacturer or model.

When using multiple devices with different background colors in this way, it is desirable to match the background colors of each device. For example, to match the background color of the optotype presentation device 10 of this embodiment to the background color of an optotype presentation device that uses a tungsten lamp or the like, the user operates the operation unit 15 to select a low color temperature of 2000K or 3000K.

The operation unit 15 generates a signal corresponding to the selected color temperature and outputs it to the control unit 14. The control unit 14, which receives this signal, searches the gradation value table T2 based on the selected color temperature and acquires the gradation value of each pixel of RGB color corresponding to the color temperature. The control unit 14 controls the optotype display unit 12a based on the acquired gradation value, so that the background 102 is displayed in the image display area 100 of the optotype display unit 12a with the background color adjusted to a color corresponding to the selected color temperature. Therefore, in the first embodiment, it is possible to provide an optotype presentation device 10 that can easily change the background color of the optotype to a desired color. As a result, it is possible to unify the background colors of multiple optotype presentation devices to the same color or similar colors.

Then, once the background color has been set, the examiner operates the operation button 15b of the operation unit 15 to display a specified optotype on the optotype presentation device 10 and measure the ocular characteristics of the subject P's eye E. Under the control of the control unit 14, the optotype presentation device 10, which has received this operation instruction signal, displays the background 102 in a preset background color in the image display area 100 of the optotype display unit 12a, and displays the optotype. This allows the subject P to measure the ocular characteristics of the subject's eye E. And because the background colors of multiple optotype presentation devices are the same, the subject P does not feel uncomfortable even when multiple optotype presentation devices are used for the test, and the subject P can take the test comfortably.

If the color information selected by the user and the luminance values of the corresponding pixels of each color are stored in memory 13, from the next test onwards, control unit 14 can control optotype display unit 12a based on the gradation values of the pixels of each color stored in memory 13. This eliminates the need for the examiner to select the background color every time a test is performed, making it possible to perform efficient measurements.

In the first embodiment, the optotype display unit 12a is an electronic display device that has a plurality of pixels including at least the three colors of RGB, and can display the optotype in color by changing the gradation of the pixels of each color. The control unit 14, which functions as a background color setting unit, calculates the gradation of the pixels of each color corresponding to the background based on the color information, and controls the electronic display device (optotype display unit 12a) based on the calculation result to change the gradation of the pixels, thereby setting the background color. This makes it possible to determine the gradation of each pixel while taking into account the balance of the luminance ratio of the pixels of each color, such as RGB, and to set the background color to the desired hue without reducing the apparent brightness of the background.

The first embodiment also includes a storage unit (memory 13) that stores tables (conversion table T1, gradation value table T2) that associate each piece of color information with the gradation of pixels of each color. The background color setting unit (control unit 14) calculates the gradation of each color pixel corresponding to the background based on the color information received by the input unit (operation unit 15) and the gradation of each color pixel obtained from the table in the storage unit (memory 13). This configuration allows the gradation of each pixel to be determined more appropriately and quickly, and allows the background color to be set more appropriately and quickly.

In the first embodiment, the color information is the color temperature of the background color, and the input unit (operation unit 15) is configured to be able to select at least two or more color temperatures. With this configuration, the user can select the hue of the background color of the optotype presentation device 10 according to the background color of the other device or according to the user's preference. In particular, in the first embodiment, a selection can be made from seven color temperatures, which increases the number of options for the hue of the background color and increases the freedom to set the hue of the background color, allowing the background color to be set more appropriately according to the background color of the other device or the user's preference. Even if the hue of the background color of the other device changes due to device replacement or the like, the hue of the background color of the optotype presentation device 10 can be appropriately changed according to that hue.

As a variant, the color information can be a color name. The color names (light source colors) of light from light sources, etc., and the color temperatures corresponding to the color names are defined by the JIS standard (JIS Z 9112:2019), as shown in Table 1 below. For this reason, if color information can be selected by color name from the operation unit 15, the hue of the background color can be set based on the color temperature corresponding to that color name.

Figure 3 (2) shows a schematic diagram of a modified operation unit 15 that allows selection by color name. As shown in Figure 3 (2), when the user operates the color selection button 15c, the color name such as "warm white" is displayed on the color display unit 15d. Information on the selected color name is input as a signal from the operation unit 15 to the control unit 14.

In the optotype presentation device 10, for example, a table in which each color name is associated with an optimal color temperature (for example, the median of the color temperature range shown in Table 1) is stored in advance in the memory 13. Then, based on the color name input from the operation unit 15, the control unit 14 selects a color temperature from the table, and similarly to the first embodiment, obtains the luminance value of the pixel of each color from the conversion table T1 and the gradation value table T2, and controls the optotype display unit 12a based on the obtained luminance value to set the background color.

In this way, even if the color information is a color name, the hue of the background color can be set appropriately, and furthermore, compared to when selecting by color temperature, the user can easily imagine the background color by the color name, and can select the hue of the background color more appropriately. By allowing the user to select from at least two color names, and preferably five or more as shown in Table 1, the freedom of hue selection is increased, and the hue of the background color can be set more appropriately.

Second Embodiment
Next, the optotype presenting device 10 according to the second embodiment will be described with reference to Fig. 5. The optotype presenting device 10 according to the second embodiment shown in Fig. 5 has the same basic configuration as the optotype presenting device 10 according to the first embodiment shown in Fig. 1, etc., except that it further includes an eye examination unit 17 and a second optotype display unit 19 for near vision eye examination. Therefore, in the following, detailed descriptions of the configuration and operation similar to those of the first embodiment will be omitted, and configurations and operations different from those of the first embodiment will be mainly described.

The optotype presentation device 10 according to the second embodiment shown in FIG. 5 includes a main body 1 incorporating an optotype presentation optical system 12, a memory 13, and a control unit 14 in a housing 11, an operation unit 15 as an input unit, an eye examination table 16 (see FIG. 1), an eye examination unit 17, a support unit 18 that supports the eye examination unit 17, and a second optotype display unit 19 for near vision eye examination.

The eye examination unit 17 is provided with a near point rod 17b extending horizontally on the main body 1 side. A second optotype display unit 19 for near vision examination is suspended from the tip or midway of this near point rod 17b at a position at the near vision examination distance (e.g., 300 to 400 mm from the eye E to be examined). The near point rod 17b is foldable, and when not in use, the near point rod 17b and the second optotype display unit 19 can be stored vertically.

The eye examination unit 17 also includes a light source 17a on the main body 1 side that illuminates the second optotype display unit 19. This light source 17a can be, for example, an LED that can change color.

The second optotype display unit 19 displays an optotype for near vision examination. This second optotype display unit 19 uses a plate-shaped member or paper with the optotype printed on it, but an electronic display device such as an LCD can also be used. This second optotype display unit 19 can be moved back and forth along the near point rod 17b, allowing the near vision examination distance to be changed as desired. By performing near vision examination using this second optotype display unit 19, it is possible to check for changes in the accommodation power of the subject's eye E due to aging, etc.

The optotype presentation device 10 of the second embodiment can change the color of the light source 17a under the control of the control unit 14 based on color information (color temperature, color name) input from the operation unit 15, thereby making it possible to set the background color of the second optotype display unit 19 illuminated by this light source 17a to a desired color. As in the first embodiment, the background color of the optotype display unit 12a of the main body unit 1 can also be set to a desired color under the control of the control unit 14. That is, the color of the background color of either the optotype display unit 12a or the second optotype display unit 19 can be changed to match the color of the other background color, or the color of both background colors can be changed to match the color of the background color of the optotype presentation device other than these.

In order to set the color of the background color of the second optotype display unit 19, in the second embodiment, for example, a table in which color information and the emission color information of the light source 17a are associated with each other for each color information is stored in advance in the memory 13. Then, based on the color information input from the operation unit 15, the control unit 14 searches the table, acquires the corresponding emission color information, and causes the light source 17a to emit light based on the acquired emission color information. By irradiating light from the light source 17a whose emission color has been adjusted in this way, the background color of the second optotype display unit 19 can be set to the color information (color temperature, color temperature corresponding to the color name) set by the user. Note that, for example, chromaticity such as xy chromaticity can be used as the emission color information. For example, using an xy chromaticity diagram, the x and y chromaticities corresponding to the color temperature can be acquired based on the approximate blackbody radiation locus on this xy chromaticity diagram and the selected color temperature.

As described above, the optotype presenting device 10 of the second embodiment can achieve the same effects as those of the first embodiment. That is, the optotype presenting device 10 of the second embodiment includes an optotype display unit 12a and a second optotype display unit 19 that present optotypes for testing eye characteristics to the subject's eye E, an input unit (operation unit 15) that accepts designation of color information (e.g., color temperature, color name) related to the background color of the optotypes to be displayed, and a background color setting unit (control unit 14) that sets the background color of the optotype based on the color information accepted by the input unit. Therefore, the background color of the optotype of the optotype display unit 12a and/or the second optotype display unit 19 can be easily set to a desired color.

Furthermore, in the second embodiment, the optotype display unit (second optotype display unit 19) includes a light source 17a that illuminates the background. The background color setting unit (control unit 14) controls the light source 17a based on color information received by the input unit (operation unit 15) to change the chromaticity of the light source 17a to set the background color, and therefore the background color of the optotype illuminated by the light from the light source 17a can be set to a desired color.

The optotype presenting device 10 of the second embodiment has two optotype display units, an optotype display unit 12a consisting of an electronic display device provided in the main body unit 1, and a second optotype display unit 19 for near vision examination, and the background color of these optotypes can be set to a desired color, but is not limited to this configuration. For example, the optotype presenting device may be equipped with only the second optotype display unit 19 for near vision examination, or may be equipped with this second optotype display unit 19 and a paper optotype display unit placed at a distance for far vision examination (e.g., 5 m), or an optotype display unit that projects the optotype on a screen. And, by adjusting the emission color of the light source that illuminates these optotype display units, the background color on which the optotype is displayed can be changed to a desired color.

The visual target presentation device 10 of the present invention has been described above based on the embodiments, but the specific configuration is not limited to these embodiments, and design changes and additions are permitted as long as they do not deviate from the gist of the invention according to each claim in the scope of the claims.

For example, in the optotype presentation device 10 of each of the above embodiments, a conversion table T1 and a gradation value table T2 are stored in the memory 13. These tables are prepared by measuring the spectral characteristic values of the electronic display device and light source installed in each optotype presentation device 10 during manufacture of the optotype presentation device 10, calculating appropriate correction values and initial values corresponding to the obtained spectral characteristic values, and setting the tables, so that the color of the background can be reproduced with higher accuracy.

In addition, in each of the above embodiments, the conversion table T1 and the gradation value table T2 are used as tables in which color information and the gradation of each RGB color pixel are associated with each other, but this is not limiting. For example, only the gradation value table T2 may be used. Also, without using such a table, the control unit 14 may be configured to calculate the gradation of each color pixel using a predetermined formula based on color information such as color temperature and the type and optical characteristic values of the optotype display unit 12a and light source 17a.

10 Optotype presentation device 12a Optotype display unit 13 Memory (storage unit)
14 Control unit (background color setting unit)
15 Operation unit (input unit)
17a Light source 102 Background E Eye to be examined

Claims (4)

an optotype display unit that presents an optotype for testing eye characteristics to a subject's eye;
an input unit for receiving designation of color information regarding the color of a background on which the optotype is displayed;
a background color setting unit that sets a white color, which is a background color of the optotype, based on the color information received by the input unit;
A storage unit ,
The optotype display unit includes an electronic display device having a plurality of pixels including at least three colors of RGB, and capable of displaying the optotype in color by changing the gradation of the pixels of each color;
the storage unit stores a table in which, for each of the color information, the color information, an initial value of a gradation of the pixel of each color, and a correction value for converting the gradation of the pixel of each color from the initial value to a value corresponding to the color information, the correction value being set based on a spectral characteristic of the electronic display device;
the background color setting unit obtains a correction value corresponding to the spectral characteristics of the electronic display device from the table in the memory unit based on the color information received by the input unit, calculates a gradation of the pixel of each color corresponding to the background based on the obtained correction value and the initial value, and controls the electronic display device based on the calculation result to change the gradation of the pixel, thereby setting the white color of the background color . 2. The visual target presenting device according to claim 1, wherein a correction value for the gradation of each pixel is preset so as to be able to control the color tone substantially along a blackbody radiation locus. The optotype display unit includes a light source that illuminates the background,
3. The visual target presentation device according to claim 1 , wherein the background color setting unit sets the background color by controlling the light source to change the chromaticity of the light source based on the color information. The visual target presentation device according to any one of claims 1 to 3, characterized in that the color information is either a color temperature of the background color or a color name corresponding to the color temperature, and the input unit is configured to be able to select at least two or more of the color temperatures and at least two or more of the color names.