JP7345260B2 - Information display device, information display method, and information display program - Google Patents

Description

The present invention relates to an information display device, an information display method, and an information display program.

There is a known technique in which an illuminance value detection means is provided in front of an information display board, and when the output of the illuminance value detection means is equal to or higher than a preset value, the LED of the information display board is blinked (Patent Document 1, reference). As a result, information can be displayed conspicuously by blinking LEDs in a state where the illuminance of sunlight irradiating the front surface of the information display board increases.

Japanese Patent Application Publication No. 2006-301207

However, in a state where the illuminance of sunlight irradiating the front surface of the information display board increases, visibility by the LEDs does not necessarily decrease. Specifically, even if the front of the information display board is strongly irradiated with sunlight, if the sunlight is not reflected in the direction of the viewer at the front of the information display board, the visibility of the light emitted by the LEDs will be greatly reduced. less likely. Conversely, even if the front of the information display board is not strongly irradiated with sunlight, if sunlight is reflected in the direction of the viewer from the front of the information display board, the visibility of the light emitted by the LEDs will be greatly reduced. More likely.
The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a technology that can display information while increasing the luminance of the light emitting elements when the influence of sunlight reflection on the display surface is large. .

In order to achieve the above object, the information display device of the present invention includes a display surface in which a plurality of light emitting elements are arranged in a planar manner, a solar altitude measurement section that measures the solar altitude, and a display surface that measures the reflected brightness of sunlight on the display surface. When a solar altitude with a first luminance is measured, the light-emitting element is caused to emit light at a first luminance, and when a solar altitude is measured with a second luminance where the reflected luminance is less than the first luminance, the light-emitting element is caused to emit light with a first luminance. and a light emission control section that causes light to be emitted at a second light emission brightness that is lower than the light emission brightness.

In order to achieve the above object, the information display method of the present invention is an information display method that controls the luminance of a plurality of light emitting elements arranged in a plane on a display surface, and includes a solar altitude measurement step of measuring solar altitude. When a solar altitude is measured where the reflected brightness of sunlight on the display surface is equal to or higher than a reference value, the light emitting element is caused to emit light at the first emission brightness, and when a solar altitude is measured where the reflected brightness is less than the reference value. and a light emission control step of causing the light emitting element to emit light at a second light emission brightness that is lower than the first light emission brightness.

In order to achieve the above object, the information display program of the present invention is an information display program that causes a computer to function as an information display device that controls the luminance of a plurality of light emitting elements arranged in a plane on a display surface. is a solar altitude measurement unit that measures the solar altitude, and when a solar altitude is measured at which the reflected brightness of sunlight on the display surface is equal to or higher than a reference value, the light emitting element is made to emit light at a first emission brightness, and the reflected brightness is the reference value. The light emitting element functions as a light emission control unit that causes the light emitting element to emit light at a second light emission brightness lower than the first light emission brightness when a solar altitude lower than the first light emission brightness is measured.

In the configuration of the present invention described above, the solar altitude measuring section measures the solar altitude. The light emission control unit controls the light emitting element so that the light emission brightness increases when the solar altitude is such that the reflected brightness of sunlight on the display surface becomes high. As a result, in a situation where the display surface strongly reflects sunlight and the light from the light emitting elements can be visually recognized as being mixed with the reflected light, the luminance of the light emitting elements can be increased. Therefore, information can be displayed while reducing the influence of sunlight reflection on the display surface.

FIG. 2 is a block diagram of an information display device. 2A is a front view of the information display device, FIG. 2B is a front view of the solar altimeter, and FIG. 2C is a schematic cross-sectional view of the solar altimeter. FIG. 3A is an explanatory diagram of reflected luminance, FIG. 3B is a graph of reflected luminance ratio, and FIG. 3C is a graph of illuminance ratio. FIGS. 4A and 4B are graphs of luminance. It is a flowchart of information display processing. It is a graph of luminance.

Here, embodiments of the present invention will be described in the following order.
(1) Configuration of information display device:
(2) Information display processing:
(3) Other embodiments:

(1) Configuration of information display device:
FIG. 1 is a block diagram showing the configuration of an information display device 10 according to an embodiment of the present invention. The information display device 10 includes a control section 20, a recording medium 30, a display board 40, a solar altimeter 50, and an illuminance meter 60. The control unit 20 is a computer including a CPU, RAM, ROM, etc., and executes an information display program 21 recorded on a recording medium 30 or the like.

The recording medium 30 records a solar altitude dependent table 30a1, an illuminance dependent table 30a2, and display image data 30b. The solar altitude dependent table 30a1 and the illuminance dependent table 30a2 are lookup tables for setting the luminance of the plurality of light emitting elements P provided on the display board 40. Details of the solar altitude dependent table 30a1 and the illuminance dependent table 30a2 will be described later.

The display image data 30b is image data indicating a display image displayed on the display board 40. The display image is an image that includes characters and patterns indicating various information such as traffic information and weather information. The display image data 30b may be recorded on the recording medium 30 in advance, or may be dynamically generated by the control unit 20. The display image data 30b of this embodiment is image data that is composed of pixels corresponding to each of the plurality of light emitting elements P provided on the display board 40, and each pixel indicates whether or not the light emitting element P emits light. .

FIG. 2A is a front view of the display board 40. The display board 40 is a rectangular housing including a display surface T on which a plurality of light emitting elements P are arranged in a plane. A display board 40 is installed so that a driver of a vehicle traveling on a road can visually recognize the display surface T. That is, the display board 40 is installed above the road surface so that the display surface T is vertical and perpendicular to the traveling direction of the vehicle. In this embodiment, each of the plurality of light emitting elements P is composed of LEDs of three colors of red, green, and blue (RGB channels). Moreover, the light emitting element P may be a monochromatic LED. Of course, the light emitting element P may be a light emitting element other than an LED.

As shown in FIG. 1, the display board 40 includes a driver circuit D. The driver circuit D receives from the control unit 20 light emission image data that is image data of each RGB channel having the same pixel arrangement as the arrangement of the plurality of light emitting elements P. Each pixel of the luminescence image data indicates a multi-gradation luminance luminance gradation value for each RGB channel. The driver circuit D causes the LEDs of each RGB channel to emit light at a duty ratio according to the magnitude of the gradation value of the luminance. The control unit 20 generates luminescence image data based on the display image data 30b. The configuration for generating luminescence image data will be described later.

The display board 40 includes a solar altimeter 50 and an illuminance meter 60 on the sides of the display surface T. The illumination meter 60 measures the illuminance of light (mainly sunlight) irradiated onto the display surface T, and outputs a signal indicating the illuminance to the control unit 20. The solar altimeter 50 constitutes a part of the solar altimeter H of the present invention. The solar altimeter 50 and the illumination meter 60 do not necessarily have to be on the sides of the display surface T. Further, the solar altimeter 50 does not need to be integrated with the display board 40 and may be attached outside the display board 40. The illuminance meter 60 corresponds to the illuminance measuring section of the present invention.

FIG. 2B shows a front view of the solar altimeter 50 (a view seen from vertically in front of the display surface T). FIG. 2C is a schematic cross-sectional view of the solar altimeter 50 (a cross-sectional view in the vertical direction of the display surface T). As shown in FIGS. 2B and 2C, the solar altimeter 50 is embedded inside the display board 40. The solar altimeter 50 includes a case 51, a transparent cover 52, a polarizing filter 53, a color filter 54, a slit plate 55, an optical sensor 56, a substrate 57, and an output circuit 58.

A rectangular detection window W is formed that passes through the front panel 41 and the case 51 that constitute the housing of the display panel 40 in the front-rear direction, and the detection window W is a part of the transparent cover 52 . The polarizing filter 53 is a filter that transmits horizontally polarized light of the light incident on the detection window W. The color filter 54 is a filter that transmits light in a predetermined wavelength range. In this embodiment, the color filter 54 is a filter that transmits light in the near-infrared to infrared region.

The slit plate 55 is made of a non-transparent material, and has elongated slits 55a formed in the horizontal direction. The slit 55a is a horizontal notch that transmits sunlight emitted by the sun at a solar altitude α within a predetermined measurement range M (from the lower limit direction α _L to the upper limit direction α _U ). The slit 55a has a trapezoidal shape in a vertical cross-sectional view. In this embodiment, the lower limit direction α _L is a direction perpendicular to the front plate 41 and is a horizontal direction. The upper limit direction α _U is a direction inclined by 30 degrees from the lower limit direction α _L.

The optical sensor 56 is a sensor that receives sunlight that has passed through the slit 55a. The optical sensor 56 is an area image sensor in which a large number of photoelectric conversion elements are arranged on a vertical plane. The optical sensor 56 is arranged so that it can image the light of the entire measurement range M that has passed through the slit 55a. The optical sensor 56 has a width narrower than the slit 55a so that even if sunlight passes through the slit 55a with a 10 degree swing to the left or right, the entire width of the sensor is illuminated. The optical sensor 56 is mounted on the front side of the board 57. The substrate 57 is made of a non-transparent material and closes an opening provided on the rear side of the case 51. The case 51 is formed into a rectangular parallelepiped shape using a non-transparent material, and light can enter the inside of the case 51 from the outside only through the slit 55a.

The output circuit 58 is mounted on the rear side of the board 57. The output circuit 58 generates measurement image data that is image data of the image formed by the optical sensor 56, and outputs the measurement image data to the control unit 20. The measurement image data is image data that is composed of pixels in which the vertical and horizontal coordinates of the photoelectric conversion element included in the optical sensor 56 are associated with each other, and each pixel indicates brightness. Note that the order in which the polarizing filter 53, color filter 54, and slit plate 55 are arranged in the front-rear direction is not limited to the illustrated order.

Next, the software configuration of the information display device 10 will be explained. The information display program 21 includes a solar altitude measurement module 21a and a light emission control module 21b. The solar altimeter 50 and the control unit 20 that executes the solar altitude measurement module 21a constitute the solar altitude measurement unit H of the present invention. The control section 20 that executes the light emission control module 21b constitutes the light emission control section of the present invention.

The control unit 20 measures the solar altitude α using the function of the solar altitude measurement module 21a. Specifically, using the function of the solar altitude measurement module 21a, the control unit 20 acquires the measurement image data output from the solar altimeter 50, and calculates the solar altitude α based on the measurement image data. The control unit 20 calculates the average brightness of each of the pixel rows arranged in the horizontal direction on the optical sensor 56, and calculates the solar altitude α based on the vertical coordinates of the pixel row with the maximum average brightness.

Specifically, the control unit 20 calculates the angle between the horizontal line and the straight line connecting the position on the optical sensor 56 of the pixel row with the maximum average brightness and the position of the slit 55a as the solar altitude α. The lower the vertical position of the pixel row with the maximum average brightness is, the greater the solar altitude α becomes. Here, the solar altitude α is the elevation angle when looking up at the sun from the position of the slit 55a. Note that the optical sensor 56 may be any sensor in which photoelectric conversion elements are arranged at least in the height direction, and may be a line sensor.

If the average brightness of the pixel row with the maximum average brightness is less than a predetermined threshold, the control unit 20 determines that the solar altitude α cannot be measured. In this embodiment, the solar altitude α is measured only when the width of the slit 55a is wider than the width of the optical sensor 56 and the sun is present within a deflection angle range of 10 degrees left and right from the front direction of the display surface T in the horizontal direction. It becomes possible. Furthermore, when there is insufficient sunlight at night or in bad weather, it is determined that the solar altitude α cannot be measured.

By the function of the light emission control module 21b, the control unit 20 causes the light emitting element P to emit light at the first light emission brightness when the solar altitude α at which the reflected brightness of sunlight on the display surface T becomes the first brightness, When a solar altitude α is measured at which the second luminance is lower than the first luminance, the light emitting element P is caused to emit light at a second luminance that is lower than the first luminance. Specifically, using the function of the light emission control module 21b, the control unit 20 acquires the light emission brightness corresponding to the measured solar altitude α from the solar altitude dependent table 30a1, and causes the light emitting element P to emit light at the light emission brightness.

Hereinafter, the creation theory and structure of the solar altitude dependence table 30a1 will be explained. FIG. 3A is a vertical cross-sectional view of the display surface T, showing the detailed configuration of the light emitting element P. The light emitting element P includes an LED mounting part P1 and a lens P2. The LED mounting portion P1 includes metal, semiconductor, etc., and has high reflectance. A louver 42 that does not have light-transmitting properties protrudes forward between vertically adjacent light emitting elements P. The louver 42 limits the direction of light incident on the light emitting element P and light emitted from the light emitting element P to near the vertical direction (for example, within 20 degrees).

When the incident light S is incident on the light emitting element P, the incident light S is mainly reflected at the LED mounting portion P1, and horizontal reflected light F may be generated. In FIG. 3A, the shape of the LED mounting portion P1 is simply shown as a rectangle, but the LED mounting portion P1 constitutes a complex reflective surface having unevenness. Further, the shape of the lens P2 is not necessarily vertically symmetrical either. Therefore, even if the incident light S enters obliquely from above, reflected light F in the horizontal direction may occur. The solar altitude α at which the brightness of the reflected light F in the horizontal direction is maximum depends on the shape of the light emitting element P. Furthermore, the display surface T does not necessarily have to be a vertical surface; for example, the display board 40 may be attached so that the display surface T is tilted downward by several degrees (for example, 3 degrees) from the vertical direction. Therefore, the solar altitude α at which the intensity of the reflected light F in the horizontal direction is maximum also depends on the mounting angle (depression angle) of the display board 40.

In this embodiment, assuming that the display surface T is viewed from the horizontal direction, a luminance meter B is installed in front of the display surface T so that the direction of the measurement optical axis Q is in the horizontal direction, and a luminance meter B is installed at each solar altitude. The reflected brightness at α was measured. It is assumed that the sun is always located in front of the display surface T in the horizontal direction. Measurement of reflected brightness may be performed while rotating the display surface T horizontally so as to track the actual sun, or by fixing the display surface T and moving a light source imitating the sun in the vertical direction. It may be done by.

FIG. 3B is a graph showing reflected brightness at each solar altitude α. The horizontal axis of FIG. 3B shows the solar altitude α, and the vertical axis shows the reflected brightness ratio RR. The reflected brightness ratio RR is a ratio obtained by dividing the reflected brightness at each solar altitude α by the maximum value of the reflected brightness. In FIG. 3B, when the solar altitude α becomes α ₁ , the reflected brightness becomes maximum and the reflected brightness ratio RR becomes 100%.

As shown in FIG. 3A, since the display surface T is provided with the louver 42, the reflected brightness ratio RR increases at the solar altitude α where the direction of the incident light S becomes close to horizontal. The range of solar altitude α in which the reflection brightness ratio RR is equal to or higher than a predetermined threshold value RR _T is defined as a high reflection range K. Of course, the reflection range K includes the solar altitude α ₁ where the reflected brightness is maximum. Further, the shape of the slit 55a is set so that the measurement range M in which the solar altitude α can be measured includes the high reflection range K. Therefore, the measurement range M includes the solar altitude α ₁ where the reflected brightness is maximum. In this embodiment, the solar altitude α ₁ at which the reflected brightness is maximum is about 10 degrees, and the upper limit of the high reflection range K is about 20 degrees. Therefore, the solar altitude α in the high reflection range K is measured during a time period close to sunset.

As described above, the solar altitude α can be measured only when the sun exists in a direction close to the front direction of the display surface T in the horizontal direction. Therefore, if the display surface T is installed facing north or south, the solar altitude α will not be within the high reflection range K throughout the day. When the display surface T is installed so as to face eastward, the solar altitude α may be within the high reflection range K during a time period close to sunrise. Further, when the display surface T is installed so as to face westward, the solar altitude α may be within the high reflection range K during a time period close to sunset.

FIG. 3C is a graph showing the illuminance measured by the illuminance meter 60. The horizontal axis of FIG. 3C shows the solar altitude α, and the vertical axis shows the illuminance ratio IR. The illuminance ratio IR is a ratio obtained by dividing the illuminance measured by the illuminance meter 60 at each solar altitude α by the maximum value of the illuminance. In FIG. 3C, when the solar altitude α becomes α ₃ , the illuminance becomes maximum and the illuminance ratio IR becomes 100%. The solar altitude α ₃ where the illuminance is maximum is approximately 30 to 35 degrees, which is larger than the high reflection range K where the reflection brightness ratio RR is large. Therefore, it can be understood from FIGS. 3B and 3C that at the solar altitude α where the illuminance ratio IR becomes large, the reflected luminance ratio RR does not necessarily become large.

FIG. 4A is a graph showing the luminance luminance L defined in the solar altitude dependence table 30a1. The horizontal axis of FIG. 4A shows the solar altitude α, and the vertical axis shows the luminance L. In the solar altitude dependent table 30a1, the gradation value of the luminance luminance L is defined for each solar altitude α belonging to the high reflection range K. The solar altitude dependence table 30a1 is created in advance based on the measurement results of reflected luminance shown in FIG. 3B. The solar altitude dependence table 30a1 is created such that the emission brightness L increases as the solar altitude α increases the reflected brightness ratio RR in FIG. 3B. The control unit 20 acquires the gradation value of the luminance luminance L corresponding to the measured solar altitude α from the solar altitude dependent table 30a1, and causes the light emitting element P to emit light at the gradation value of the luminance luminance L. Note that at the solar altitude α ₁ where the reflection brightness ratio RR is maximum (100%), the emission brightness L becomes the maximum value L _max , and at the solar altitude α where the reflection brightness ratio RR becomes the threshold value RR _T , the emission brightness L reaches the minimum value L It becomes _min .

Here, the solar altitude dependent table 30a1 may be created assuming that the display surface T is viewed from a direction other than the horizontal direction. Specifically, by installing the luminance meter B so that the angle of elevation when the viewer visually recognizes the display surface T matches the direction of the measurement optical axis Q, the reflection for creating the solar altitude dependent table 30a1 is performed. Luminance may also be measured.

Upon acquiring the display image data 30b to be displayed, the control unit 20 converts the display image data 30b into luminescence image data. As described above, each pixel of the display image data 30b corresponds to each light emitting element P, and indicates whether or not to cause the LED of each RGB channel to emit light. Among the pixels forming the display image data 30b, the control unit 20 sets the gradation value of the light emission brightness L corresponding to the measured solar altitude α in the solar altitude dependent table 30a1 for the pixels indicating that they emit light. On the other hand, the control unit 20 sets the gradation value of the light emission luminance L to 0 for pixels that indicate not to emit light among the pixels forming the display image data 30b. The control unit 20 sets the gradation value of the light emission luminance L for each RGB channel.

Using the function of the light emission control module 21b, the control unit 20 sets the light emission brightness L of the light emitting element P based on the illuminance and the solar altitude α. Specifically, when the measured solar altitude α is within the high reflection range K, the control unit 20 sets the gradation value of the luminance brightness L based on the solar altitude α, and when the measured solar altitude α is within the high reflection range K, the control unit 20 If it is not within the reflection range K, the gradation value of the light emission luminance L corresponding to the illuminance measured by the illumination meter 60 is set. Note that a case where the solar altitude α is not within the high reflection range K also includes a case where the solar altitude α cannot be measured.

FIG. 4B is a graph showing the luminance L defined in the illuminance dependency table 30a2. The horizontal axis in FIG. 4B shows the illuminance I, and the vertical axis shows the luminance L. In the illuminance dependent table 30a2, the gradation value of the light emission luminance L is defined for each illuminance I. The illuminance dependent table 30a2 is created such that the luminance L increases as the illuminance I increases. If the measured solar altitude α is not within the high reflection range K, the control unit 20 acquires the gradation value of the luminance luminance L corresponding to the measured illuminance I from the illuminance dependent table 30a2, and sets the gradation value of the luminance luminance L The light emitting element P is caused to emit light at the adjusted value.

If the measured solar altitude α is not within the high reflection range K, the control unit 20 sets the luminance brightness L corresponding to the measured illuminance I for the pixels that indicate emitting light among the pixels forming the display image data 30b. Set the gradation value. On the other hand, the control unit 20 sets the gradation value of the light emission luminance L to 0 for pixels that indicate not to emit light among the pixels forming the display image data 30b.

After each pixel generates the luminescence image data indicating the gradation value of the luminance luminance L in the above manner, the control section 20 outputs the luminescence image data to the driver circuit D. Thereby, the driver circuit D causes the LEDs of each RGB channel included in the light emitting element P to emit light at a duty ratio according to the magnitude of the gradation value of the light emission luminance L.

In the configuration of the present invention described above, _the control unit 20 controls the light-emitting element _P to the first When the light emitting element P is emitted at a luminance of L ₁ and a solar altitude α ₂ is measured at which the reflected luminance ratio RR becomes a second luminance ratio RR ₂ that is less than the first luminance ratio RR ₁ , the light emitting element P is set to a luminance of less than the first luminance L ₁ . The second light emission brightness L ₂ is also lower (FIG. 3B, FIG. 4A). That is, the control unit 20 controls the light emitting elements P to emit light so that the light emission brightness L increases when the solar altitude α is such that the reflected brightness of sunlight on the display surface T becomes high. Thereby, in a situation where the display surface T strongly reflects sunlight and the light from the light emitting element P can be visually recognized as being mixed with the reflected light F, the luminance of the light emitting element P can be increased. Therefore, information can be displayed while reducing the influence of sunlight reflected on the display surface T.

In addition, since the solar altitude measurement unit H includes a slit plate 55 in which a slit 55a is formed that transmits sunlight emitted by the sun at a solar altitude α within a predetermined measurement range M, the reflected brightness is increased. The solar altitude α can only be measured within this range. Furthermore, by limiting the width of the slit 55a in the horizontal direction, the solar altitude α can be measured when the sun is present near the front of the display surface T in the horizontal direction. Therefore, when viewing the display surface T from the front, the influence of sunlight reflected on the display surface T can be reduced. Since this measurement range M includes the solar altitude α ₁ at which the reflected brightness ratio RR is maximum, the solar altitude α ₁ at which the visibility of information is most degraded due to the reflected light on the display surface T can be measured.

Moreover, since the solar altitude measurement unit H includes the polarizing filter 53 that transmits horizontally polarized light, it is possible to reduce the influence of noise due to polarized light other than horizontally, and to accurately measure the solar altitude α. Furthermore, since the solar altitude measurement unit H includes a color filter 54 that transmits light in a predetermined wavelength range, the amount of sunlight that enters the optical sensor 56 can be adjusted appropriately. Furthermore, since the control unit 20 sets the light emission brightness L of the light emitting element P based on the illuminance I and the solar altitude α, the control unit 20 causes the light emitting element P to emit light at a light emission brightness L suitable for both the illuminance I and the solar altitude α. be able to.

(2) Information display processing:
FIG. 5 is a flowchart of information display processing. First, the control unit 20 acquires measurement image data from the solar altimeter 50 using the function of the solar altimeter module 21a (step S100). Specifically, the control unit 20 acquires measurement image data captured by the optical sensor 56 of the solar altimeter 50.

Next, using the function of the solar altitude measurement module 21a, the control unit 20 calculates the solar altitude α based on the measured image data (step S110). Specifically, the control unit 20 calculates the angle between the horizontal line and the straight line connecting the position on the optical sensor 56 of the pixel row with the maximum average brightness and the position of the slit 55a as the solar altitude α. However, if the average brightness of the pixel row with the maximum average brightness is less than a predetermined threshold, the control unit 20 determines that the solar altitude α cannot be measured.

Next, using the function of the light emission control module 21b, the control unit 20 determines whether the measured solar altitude α is within the high reflection range K (step S120). That is, the control unit 20 determines whether the solar altitude α is measurable and the reflected brightness ratio RR is equal to or greater than the threshold value _RRT .

If it is determined that the measured solar altitude α is within the high reflection range K (step S120: Y), the control unit 20 sets the luminance brightness L based on the measured solar altitude α using the function of the light emission control module 21b. (Step S130). That is, the control unit 20 sets the gradation value of the luminance luminance L corresponding to the solar altitude α in the solar altitude dependent table 30a1 for the pixels that indicate that they emit light among the pixels that constitute the display image data 30b. In other words, the control unit 20 sets a higher gradation value of the light emission brightness L as the solar altitude α increases the reflection brightness ratio RR.

Next, using the function of the light emission control module 21b, the control unit 20 causes the light emitting element P to emit light at the set light emission brightness L (step S140). That is, the control unit 20 outputs light emission image data in which each pixel indicates a gradation value of the light emission brightness L to the driver circuit D. Thereby, the driver circuit D causes each LED of the RGB channels to emit light at a duty ratio according to the magnitude of the gradation value of the light emission luminance L.

On the other hand, if it is not determined that the measured solar altitude α is within the high reflection range K (step S120: N), the control unit 20 measures the illuminance I using the function of the light emission control module 21b (step S150). That is, the control unit 20 obtains the illuminance I measured by the illuminance meter 60.

Next, using the function of the light emission control module 21b, the control unit 20 sets the light emission brightness L based on the measured illuminance I (step S160). That is, the control unit 20 sets the gradation value of the light emission luminance L corresponding to the illuminance I in the illuminance dependent table 30a2 for a pixel indicating that it emits light among the pixels forming the display image data 30b. In other words, the control unit 20 sets a higher gradation value of the luminance luminance L as the illuminance I increases. Then, using the function of the light emission control module 21b, the control unit 20 causes the light emitting element P to emit light at the set light emission brightness L (step S140).

(3) Other embodiments:
FIG. 6 is a graph showing an example of a three-dimensional lookup table that defines the luminance L for each combination of the solar altitude α and the illuminance I. In the three-dimensional lookup table shown in FIG. 6, the light emission brightness L is predefined based on the combination of the solar altitude α and the illuminance I. In FIG. 6, when the solar altitude α is within the high reflection range K, the luminance luminance L changes depending on both the solar altitude α and the illuminance I, and when the solar altitude α is not within the high reflection range K, The luminance L varies depending on the illuminance I.

By having the control unit 20 refer to the three-dimensional lookup table as exemplified above, the light emission brightness L can be flexibly set according to the combination of the solar altitude α and the illuminance I. However, in the present invention, it is not essential to use a lookup table, and a function that can derive the luminance luminance L from at least the solar altitude α may be used.

In the above embodiment, FIG. 3A shows that incident light S that enters the light emitting element P made of a bullet-shaped LED from obliquely above is refracted by the lens P2, reflected by the LED mounting part P1, and becomes horizontally reflected light F. Although the case where this occurs is illustrated, reflected light in the horizontal direction also occurs in a dot matrix LED display unit in which the LED mounting part and the lens are arranged separately, or in an LED display unit without a lens. Therefore, any light emitting element that generates horizontally reflected light from the display surface when irradiated with sunlight may be a micro LED or OLED, and the shape and type of the light emitting element are not limited.

Furthermore, although the display image data 30b is binary image data, it may be multi-tone image data. In this case, the control unit 20 may set the light emission brightness L by correcting the gradation value indicated by the display image data 30b according to the solar altitude α. For example, the control unit 20 may set the light emission brightness L by acquiring a gain corresponding to the solar altitude α from the solar altitude dependent table 30a1 and multiplying the gain by the gradation value indicated by the display image data 30b. .

Furthermore, the polarizing filter 53 may be omitted from the solar altimeter 50, and the color filter 54 may be omitted. The color filter 54 is not limited to a filter that transmits infrared light, but may transmit light in other wavelength ranges. Further, when the display surface T is installed near a noise light source (for example, a traffic light) in a known wavelength range, a color filter 54 may be used that blocks light in the wavelength range of the noise light source.

Furthermore, the method of controlling the light emission of the display board based on the solar altitude as in the present invention can also be applied as a program or method. Further, it can be changed as appropriate, such as partially being software and partially being hardware. Furthermore, the invention can also be used as a recording medium for a program that controls an apparatus. Of course, the recording medium for the software may be a magnetic recording medium or a semiconductor memory, and any recording medium that will be developed in the future can be considered in exactly the same way.

DESCRIPTION OF SYMBOLS 10... Information display device, 20... Control part, 21... Information display program, 21a... Solar altitude measurement module, 21b... Light emission control module, 30... Recording medium, 30a1... Solar altitude dependent table, 30a2... Illuminance dependent table, 30b... Display image data, 40... Display board, 41... Front plate, 42... Louver, 50... Solar altimeter, 51... Case, 52... Transparent cover, 53... Polarizing filter, 54... Color filter, 55... Slit plate, 55a... Slit , 56... Optical sensor, 57... Board, 58... Output circuit, 60... Illuminance meter, B... Luminance meter, D... Driver circuit, F... Reflected light, H... Solar altitude measurement section, I... Illuminance, IR... Illuminance ratio , K...High reflection range, L...Emission brightness, M...Measurement range, P...Light emitting element, P1...LED mounting part, P2...Lens, RR...Reflection brightness ratio, T...Display surface, W...Detection window, α... solar altitude

Claims (10)

a display surface with a plurality of light emitting elements arranged in a plane;
a solar altitude measurement unit that measures the solar altitude;
a light emission control section that controls light emission of the light emitting element;
Equipped with
a range of solar altitudes in which the ratio of the reflected brightness measured in front of the display surface divided by the maximum value of the reflected brightness when sunlight is reflected on the display surface is equal to or higher than a preset threshold; The reflection range is set,
The light emission control section includes:
When the solar altitude measured by the solar altitude measurement unit is within the high reflection range, and the reflected brightness in front of the display surface is a first brightness, the light emitting element is emit light at a first emission brightness;
When the solar altitude measured by the solar altitude measurement unit is within the high reflection range, and the reflection brightness in front of the display surface is a second brightness that is lower than the first brightness. An information display device that causes the light emitting element to emit light at a second light emission brightness that is lower than the first light emission brightness. The light emission control unit increases the light emission brightness of the light emitting element as the reflected brightness at the measured solar altitude increases when the solar altitude is within the high reflection range. Information display device as described. A solar altitude in which each solar altitude is associated with the luminance of the light emitting element, which is set according to the measured value of the reflected brightness of sunlight reflected on the display surface at each solar altitude included in the high reflection range. further comprising a storage unit that stores the dependency table;
The information according to claim 1 or 2, wherein the light emission control unit refers to the solar altitude dependency table and determines the luminance of the light emitting element when the solar altitude is a value within the high reflection range. Display device. The solar altitude measurement unit includes:
a slit plate formed with horizontal slits that transmit sunlight emitted by the sun at the solar altitude within a predetermined measurement range;
an optical sensor that receives sunlight that has passed through the slit;
The information display device according to any one of claims 1 to 3, including: The measurement range includes the solar altitude at which the reflected brightness is maximum.
The information display device according to claim 4. The solar altitude measurement unit includes a polarization filter that transmits horizontally polarized light.
The information display device according to claim 5. The solar altitude measurement unit includes a color filter that transmits light in a predetermined wavelength range.
The information display device according to claim 5 or 6. further comprising an illuminance measurement unit that measures the illuminance of sunlight irradiated on the display surface,
The light emission control unit sets the light emission brightness of the light emitting element based on the illuminance and the solar altitude.
The information display device according to any one of claims 1 to 7. An information display method for controlling the luminance of a plurality of light emitting elements arranged in a plane on a display surface, the method comprising:
a solar altitude measurement process for measuring solar altitude;
a light emission control step of controlling light emission of the light emitting element;
including;
a range of solar altitudes in which the ratio of the reflected brightness measured in front of the display surface divided by the maximum value of the reflected brightness when sunlight is reflected on the display surface is equal to or higher than a preset threshold; The reflection range is set,
In the light emission control step,
When the solar altitude measured in the solar altitude measurement step is within the high reflection range and the reflected brightness in front of the display surface is a first brightness, the light emitting element is emit light at a first emission brightness;
When the solar altitude measured in the solar altitude measurement step is a value within the high reflection range, and the reflection brightness in front of the display surface is a second brightness lower than the first brightness. An information display method, wherein the light emitting element emits light at a second light emission brightness that is lower than the first light emission brightness. An information display program that causes a computer to function as an information display device that controls the luminance of a plurality of light emitting elements arranged in a plane on a display surface, the program comprising:
The computer,
a solar altitude measurement unit that measures solar altitude; and a light emission control unit that controls light emission from the light emitting element.
function as
A range of solar altitudes in which the ratio of the reflected brightness measured in front of the display surface divided by the maximum value of the reflected brightness when sunlight is reflected on the display surface is equal to or higher than a preset threshold value. A high reflection range is set ,
The light emission control section includes :
When the solar altitude measured by the solar altitude measurement unit is within the high reflection range, and the reflected brightness in front of the display surface is a first brightness, the light emitting element is emit light at a first emission brightness;
When the solar altitude measured by the solar altitude measurement unit is within the high reflection range, and the reflection brightness in front of the display surface is a second brightness that is lower than the first brightness. An information display program that causes the light emitting element to emit light at a second light emission brightness that is lower than the first light emission brightness.

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