JP2017072625A - Multi-screen display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-screen display device capable of correcting brightness and chromaticity of images to be displayed on a screen when there is any change in characteristics of a light source.SOLUTION: In a condition Sti that cumulative driving time of a light source 3 has reached a reference time i or more for changing the characteristics of the light source 3, each of image display devices Dp performs a series of correction processing to correct the brightness and the chromaticity of the display object image Imi as images for displaying on the image display device Dp of the screen 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multi-screen display device that displays video on a multi-screen composed of a plurality of screens that each of the plurality of video display devices has.

  There is a multi-screen display device as a device for displaying video on a large screen. The multi-screen display device is composed of a plurality of video display devices. In addition, the multi-screen display device includes a multi-screen configured by a plurality of screens respectively included in the plurality of video display devices. The multi-screen display device displays video on a multi-screen. The video is, for example, a color video displayed across the screens constituting the multi-screen. The video is a video taken by a camera, a video for television, or the like. Moreover, the said video is a video which shows a communication system diagram, an operation system diagram, etc., for example.

  Each video display device constituting the multi-screen display device is, for example, a projection video display device. The projection display apparatus generates image light by irradiating an image display device with light from a light source, and projects the image light on the back of a screen (screen). Thereby, an image is displayed on the screen.

  In recent years, demands such as lower power consumption of video display devices and longer life of light sources are increasing. For this reason, in each of the above video display devices, an increasing number of cases where LEDs (Light Emitting Diodes) are used as light sources. Each of the video display devices synthesizes light from a light source device including three LEDs that emit light of three primary colors of red, green, and blue, for example, by a dichroic mirror or a dichroic prism. The video display device modulates the light obtained by the synthesis into video light by an image display device such as a DMD (Digital Micromirror Device), and projects the video light indicating a color video on a screen.

  In each video display device, each LED as a light source has different characteristics. For this reason, there may be a variation in luminance and chromaticity of video light irradiated on the screen between the video display devices constituting the multi-screen display device. Note that variations in luminance and chromaticity of video light may already exist in the initial stage of the start of use of the multi-screen display device. In addition, variations in luminance and chromaticity of video light may occur as the usage time of the multi-screen display device elapses.

  When there are variations in the luminance and chromaticity of the image light, a luminance difference, a chromaticity difference, etc. are conspicuous between the screens constituting the multiscreen of the multiscreen display device. In this case, the sense of unity of the video displayed on the entire multi-screen is impaired. Therefore, it is necessary to make adjustments in each video display device so that the luminance difference and chromaticity difference are reduced between the screens constituting the multi-screen.

  Patent Document 1 discloses a technique (hereinafter also referred to as “Related Art A”) for adjusting the chromaticity of white light irradiated on a multi-screen. Specifically, each liquid crystal projector constituting the multivision system according to Related Technology A measures the brightness of white light by a sensor included in the liquid crystal projector. Each liquid crystal projector adjusts the luminance and chromaticity of white light to desired luminance and chromaticity based on the measured luminance.

  In addition, when the adjustment of the related technology A is performed after the installation of the multivision system, the white luminance and chromaticity can be kept substantially constant from the initial stage of the use of the multivision system.

  Patent Document 2 discloses a technology (hereinafter also referred to as “Related Technology B”) that automatically adjusts luminance and chromaticity between screens constituting a multi-screen without depending on a human hand. Specifically, in Related Technology B, when installing a multi-screen display device, each of the projection-type video display devices constituting the multi-screen display device is based on the luminance / chromaticity data stored in the memory. The projection display apparatus calculates target luminance and chromaticity. Each projection display apparatus adjusts the luminance and chromaticity of the video based on the target luminance and chromaticity.

JP-A-10-090645 Japanese Patent No. 4823660

  A light source may change in characteristics of the light source as the cumulative driving time of the light source becomes longer. It should be noted that the timing at which the characteristics of the light source of each video display device constituting the multi-screen display device change often differs in each video display device. For example, when a change occurs in the characteristics of some light sources of each video display device, the luminance and chromaticity of the video displayed on each screen constituting the multi-screen of the multi-screen display device are different. Therefore, in a situation where the characteristics of the light source have changed, it is required to correct the luminance and chromaticity of the video to be displayed on each screen constituting the multi-screen.

  In the related technologies A and B, when the characteristics of the light source change as the cumulative driving time becomes longer, the luminance and chromaticity of the video to be displayed on each screen of each video display device are corrected. I can't do it.

  The present invention has been made to solve such a problem, and is capable of correcting the luminance and chromaticity of an image to be displayed on a screen when the characteristics of the light source have changed. An object is to provide a screen display device.

  To achieve the above object, a multi-screen display device according to an aspect of the present invention includes a plurality of video display devices that have a screen and communicate with each other. The multi-screen display device includes a multi-screen composed of a plurality of the screens respectively included in the plurality of video display devices, and each of the video display devices includes at least one light source that is driven by emitting light. A part of the emitted light, which is the light emitted from the light source of each video display device, is used to display a video on the screen of the video display device. Is supplied, and the screen of each of the video display devices is irradiated with video light in which a part of the emitted light is modulated based on the original video indicated by the video signal. The video is displayed on a screen, and the multi-screen display device has a function of calculating target data for specifying target luminance that is target luminance and target chromaticity that is target chromaticity. Each of the images in the first situation in which the cumulative driving time of the light source is equal to or longer than a reference time for causing a change in the characteristics of the light source. Based on another part of the emitted light of the display device, the target luminance and the target chromaticity that can be expressed on the screen of the video display device by the video display device under the first situation are specified. Target image data to be calculated, and each video display device further corrects the luminance and chromaticity of the original video indicated by the video signal based on the target data corresponding to the first situation. A second calculating unit configured to calculate a correction coefficient, wherein each of the video display devices corrects the luminance and chromaticity of the original video indicated by the video signal based on the correction coefficient; Original video Performing said is a process for correcting the luminance and chromaticity of the display target image is the image to be displayed on the screen correction process shown apparatus.

  According to the present invention, each video display device has the video display device under a first situation in which the cumulative driving time of the light source is equal to or longer than a reference time for causing a change in the characteristics of the light source. Correction processing that is processing for correcting the luminance and chromaticity of the display target video that is the video to be displayed on the screen is performed.

  Thereby, the multi-screen display device can correct the luminance and chromaticity of the video to be displayed on the screen when the characteristics of the light source are changed.

It is a figure which shows typically the structure of the multi-screen display apparatus which concerns on Embodiment 1 of this invention. 1 is a front view of a multi-screen display device according to Embodiment 1 of the present invention. It is a figure for demonstrating a multiscreen. It is a figure for demonstrating 1 frame period. It is a flowchart of the image | video correction process N which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the calculation method of target chromaticity. It is a flowchart of the image | video correction process I which concerns on Embodiment 1 of this invention. It is a block diagram which shows the characteristic function structure of a multiscreen display apparatus. It is a hardware block diagram of a multi-screen display device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same components are denoted by the same reference numerals. The names and functions of the components having the same reference numerals are the same. Therefore, a detailed description of some of the components having the same reference numerals may be omitted.

<Embodiment 1>
(Configuration of multi-screen display device)
FIG. 1 is a diagram schematically showing a configuration of a multi-screen display apparatus 1000 according to Embodiment 1 of the present invention.

  In FIG. 1, the X direction, the Y direction, and the Z direction are orthogonal to each other. Each of the X direction, the Y direction, and the Z direction shown in the following figures is also orthogonal to each other. Hereinafter, a direction including the X direction and the direction opposite to the X direction (−X direction) is also referred to as “X axis direction”. In the following, the direction including the Y direction and the direction opposite to the Y direction (−Y direction) is also referred to as “Y-axis direction”. Hereinafter, a direction including the Z direction and a direction opposite to the Z direction (−Z direction) is also referred to as a “Z-axis direction”.

  Hereinafter, a plane including the X-axis direction and the Y-axis direction is also referred to as an “XY plane”. Hereinafter, a plane including the X-axis direction and the Z-axis direction is also referred to as an “XZ plane”. Hereinafter, a plane including the Y-axis direction and the Z-axis direction is also referred to as a “YZ plane”.

  FIG. 2 is a front view of multi-screen display apparatus 1000 according to Embodiment 1 of the present invention. As shown in FIGS. 1 and 2, the multi-screen display device 1000 includes video display devices 100m and 100s. The external shapes of the video display devices 100m and 100s are the same.

  Hereinafter, each of the video display devices 100m and 100s is also referred to as a “video display device Dp”. The multi-screen display device 1000 is composed of two video display devices Dp. The number of video display devices Dp constituting the multi-screen display device 1000 is not limited to 2, and may be 3 or more.

  As an example, the multi-screen display device 1000 is configured by arranging two video display devices Dp in a matrix of one row and two columns as shown in FIG.

  The video display device Dp is a projection video display device. A projection display apparatus is an apparatus that projects image light indicating an image onto the screen from the back of the screen. The video display device Dp is not limited to a projection video display device, and may be a liquid crystal display (LCD (Liquid Crystal Display)), for example.

  The external shape of each video display device Dp is a rectangular parallelepiped. Each video display device Dp is arranged in a matrix on the XY plane as shown in FIG. The shape of each video display device Dp may be a shape other than a rectangular parallelepiped as long as the video display devices Dp can be arranged in a matrix.

  A video signal Vsg described later is supplied to each video display device Dp.

  Each video display device Dp is configured to be able to communicate with each other. Specifically, each video display device Dp is connected by a communication cable 16. The communication cable 16 is, for example, a cable conforming to the RS232C communication standard. The video display devices Dp communicate with each other using the communication cable 16. FIG. 1 shows a configuration in which a video display device 100m and a video display device 100ms are connected by a communication cable 16.

  The multi-screen display device 1000 includes the multi-screen 10A shown in FIG. As shown in FIG. 3, the video display devices 100m and 100s have screens 10m and 10s, respectively. The multi-screen 10A is a single screen configured by arranging the screens 10m and 10s in a matrix. The shape of the multi-screen 10A is a rectangle.

  Hereinafter, each of the screens 10 m and 10 s is also referred to as “screen 10”. That is, the multi-screen 10A is composed of a plurality of screens 10 respectively included in the plurality of video display devices Dp. The screen 10 is a surface for displaying an image. The screen 10 is, for example, a screen. The screen 10 may be transparent glass. The number of screens 10 constituting the multi-screen 10A is not limited to 2, and may be 3 or more.

  As an example, the screen 10 of each video display device Dp is disposed on the entire front surface of the video display device Dp. Therefore, the shape of the XY plane of the multi-screen 10A in FIG. 3 is the same as the shape of the XY plane of the multi-screen display device 1000 in FIG.

  Hereinafter, the video display device 100m is also referred to as a “master device”. In the following, the video display device 100s is also referred to as a “slave device”. The multi-screen display device 1000 includes one master device and one or more slave devices.

  Next, the configuration of the video display devices 100m and 100s will be described. Referring to FIG. 1, a video display device 100m includes a screen 10, a light source device 30, a dichroic mirror 4, a relay lens 5, a TIR (Total Internal Reflection) prism 6, an image display device 7, and a control unit. 11, a memory 12, a light source control unit 14, a display characteristic calculation unit 15, a projection lens 8, a detection unit SN 1, and a calculation unit 13.

  Note that the video display device 100s differs from the video display device 100m only in that the calculation unit 13 is not provided. Since the other configuration of the video display device 100s is the same as that of the video display device 100m, detailed description will not be repeated.

  The control unit 11 has a function of performing various controls, various processes, and the like. For example, the control unit 11 controls the image display device 7. Further, the video signal Vsg is supplied to the control unit 11. The control unit 11 supplies the video signal Vsg to the image display device 7. Further, the control unit 11 has a function of performing communication. The control unit 11 of the video display device 100m and the control unit 11 of the video display device 100s are connected by a communication cable 16.

  The memory 12 has a function of storing information, data, and the like.

  The light source device 30 is a device that emits light. The light source device 30 includes light sources 3r, 3g, and 3b. The light source 3r emits red light. The light source 3g emits green light. The light source 3g emits blue light. The light sources 3r, 3g, 3b sequentially emit red light, green light, and blue light. That is, the light source device 30 sequentially emits red light, green light, and blue light.

  Hereinafter, each of the light sources 3r, 3g, and 3b is also collectively referred to as “light source 3”. Hereinafter, each of red light, green light, and blue light is also simply referred to as “color light”. The light source 3 is, for example, an LED. The light source 3 emits colored light when current is supplied to the light source 3. The light source 3 is driven by emitting light (color light). Hereinafter, the light (color light) emitted from the light source 3 is also referred to as “emitted light”. The light source 3 has a function of changing the luminance of the emitted light.

  The light source control unit 14 controls each light source 3. Specifically, the light source control unit 14 supplies a current to each light source 3. The light source control unit 14 has a function of controlling the light source 3 so that the luminance of the emitted light changes. Specifically, the light source control unit 14 changes the luminance of the light emitted from the light source 3 by changing the amount of current supplied to the light source 3.

  The light source 3 is not limited to the LED, and may be another light source. The light source 3 may be a laser, for example.

  Hereinafter, the accumulation of time during which the light source 3 is driven is also referred to as “accumulation drive time”. Hereinafter, the time for causing the characteristics of the light source 3 to change is also referred to as “reference time i” or “i”. The reference time i is a time for reducing the characteristics of the light source 3. The reference time i is, for example, 20000 hours.

  Hereinafter, the maximum value of the luminance of the emitted light emitted from the light source 3 is also referred to as “maximum luminance value YMx”. Specifically, the maximum luminance value YMx is a value of the luminance of the emitted light having the maximum luminance that can be emitted from the light source 3. Hereinafter, the maximum luminance value YMx of the luminance of the emitted light from the light source 3 when the unused light source 3 is driven for the first time is also referred to as “initial maximum luminance value”.

  The light source 3 has a characteristic that the maximum luminance value YMx of the emitted light from the light source 3 decreases as the cumulative drive time becomes longer in a state where the cumulative drive time is larger than the initial time below.

  The initial time is a time during which the initial maximum luminance value is maintained when the cumulative driving time is the initial time. The initial time is, for example, a time that is 0 or more and less than or equal to 1 / h (h is an integer of 2 or more) times the reference time i. The initial time is, for example, a time in the range of 0 to 10 hours.

  Hereinafter, a situation in which the cumulative drive time of each light source 3 included in each video display device Dp constituting the multi-screen display device 1000 is an initial time is also referred to as “situation Stn”.

  In the following, the situation where the cumulative drive time of each light source 3 included in each video display device Dp constituting the multi-screen display device 1000 is equal to or longer than the reference time i is also referred to as “situation Sti”.

  Each video display device Dp has a normal mode and a luminance reduction mode as operation modes. The normal mode is a mode in which the luminance value of the emitted light is set to the maximum luminance value YMx. Hereinafter, a value v times the maximum luminance value YMx is also referred to as a “suppression value”. The v is a real number that satisfies 0 <v <1. For example, v is 0.7.

  The luminance reduction mode is a mode in which the luminance value of the emitted light is set to the suppression value. The light source 3 in the situation Sti included in the video display device Dp in the luminance reduction mode has a lower degree of decrease in the maximum luminance value YMx than the light source 3 in the situation Sti included in the video display device Dp in the normal mode.

  The light source 3 of the video display device Dp in the brightness reduction mode is supplied with, for example, an amount v times the amount of current supplied to the light source 3 of the video display device Dp in the normal mode by the light source control unit 14. .

  The dichroic mirror 4 is configured to selectively transmit red light, green light, and blue light that are emitted light. The dichroic mirror 4 is configured to selectively reflect red light, green light, and blue light that are emitted light. When the dichroic mirror 4 is sequentially irradiated with red light, green light, and blue light, the dichroic mirror 4 combines the red light, green light, and blue light into one optical path.

  Red light, green light, and blue light sequentially pass through the relay lens 5. The red light, the green light and the blue light transmitted through the relay lens 5 are sequentially applied to the TIR prism 6.

  A total reflection surface is provided inside the TIR prism 6. The red light, the green light, and the blue light applied to the total reflection surface of the TIR prism 6 are sequentially applied to the image display device 7.

  Although the details will be described later, the detection unit SN1 is a sensor having a function of detecting light.

  In the following, the video expressed in red is also referred to as “video Ir”. In the following, the video expressed in green is also referred to as “video Ig”. In the following, the video expressed in blue is also referred to as “video Ib”. In the following, a video expressed by combining video Ir, video Ig, and video Ib on the time axis is also referred to as “video Ic”.

  The video Ic is one frame represented by the video Ir, the video Ig, and the video Ib. The frame is composed of k (integer of 2 or more) pixels. In the present embodiment, as an example, the pixel value of the pixel is expressed in the range of 0 to 255, for example. Hereinafter, each of the video Ir, the video Ig, and the video Ib is also referred to as a “monochromatic video”.

  The image display device 7 is supplied with the video signal Vsg from the control unit 11. The video signal Vsg indicates video data for expressing each single color video constituting each of a plurality of frames (still images). Hereinafter, the video represented by the video data is also referred to as “original video”. That is, the video signal Vsg represents the original video. The original video is, for example, a monochromatic video.

  The video data is composed of k pixel data. Hereinafter, the pixel data is expressed as “pixel data (Pr, Pg, Pb)”. Each of Pr, Pg, and Pb is an intensity value indicating the intensity of the color of the pixel. Each of Pr, Pg, and Pb is expressed by a real number ranging from 0 to 1 in order to express 256 types of pixel values.

  Pr is an intensity value for expressing red. Pg is an intensity value for expressing green. Pb is an intensity value for expressing blue. For example, pixel data (1, 0, 0) is a value representing a red pixel having a pixel value of 255.

  Hereinafter, the red video light indicating the video Ir is also referred to as “video light Lr”. In the following, the green image light indicating the image Ig is also referred to as “image light Lg”. In the following, the blue video light indicating the video Ib is also referred to as “video light Lb”. In the following, each of the image lights Lr, Lg, and Lb is also referred to as “monochromatic image light”.

  In the following, a period during which a single frame is a processing target is also referred to as “period Tfr” or “one frame period Tfr”. For example, when the video display device Dp is configured to display 60 frames on the screen 10 for 1 second, the period Tfr is 1/60 seconds.

  FIG. 4 is a diagram for explaining the period Tfr. Referring to FIG. 4, the period Tfr is composed of periods Tr, Tg, Tb, and Tn. The lengths of the periods Tr, Tg, and Tb are the same. Each of the periods Tr, Tg, and Tb is, for example, a period that is approximately 0.3 times the period Tfr.

  The period Tr is a period for displaying the video Ir on the screen 10. The period Tra is a period during which the screen light 10 is irradiated with the video light Lr. The period Trn will be described later.

  The period Tg is a period for displaying the video Ig on the screen 10. The period Tga is a period during which the screen light 10 is irradiated with the video light Lg. The period Tgn will be described later.

  The period Tb is a period for displaying the video Ib on the screen 10. The period Tba is a period during which the screen light 10 is irradiated with the video light Lb. The period Tbn will be described later.

  The period Tn is, for example, a period that is approximately 0.1 times the period Tfr. The period Tn is a period in which each of the light sources 3r, 3g, 3b does not emit color light.

  Note that the period Tn may be configured to be approximately 0.03 times as long as the period Tfr. In this configuration, the period Tn is further provided between the periods Tr and Tg and between the periods Tg and Tb.

  Referring to FIG. 1 again, the image display device 7 generates monochromatic video light. Specifically, the image display device 7 outputs monochromatic video light based on the color light (red light, green light, or blue light) emitted from the dichroic mirror 4 and the video signal Vsg according to the control of the control unit 11. Generate. In other words, the image display device 7 generates monochromatic video light by modulating color light based on the original video (video data) indicated by the video signal Vsg. The image display device 7 is, for example, a DMD.

  The image display device 7 has k micromirrors. The k micromirrors are arranged in a matrix. The image display device 7 controls the inclinations of the k micromirrors based on the video data indicated by the video signal Vsg. The color light from the TIR prism 6 is applied to each micromirror of the image display device 7. Each micromirror reflects color light.

  Hereinafter, the light propagating toward the screen 10 by being reflected by the micromirror is also referred to as “on light”. In the following, light that does not propagate to the screen 10 by being reflected by the micromirror is also referred to as “off light”. In the present embodiment, the detection unit SN1 is arranged in the optical path of off light. Therefore, the off-light is light that propagates toward the detection unit SN1.

  By the image display device 7, the state of each micromirror is controlled to either the on state or the off state. The on state is a state in which the inclination of the micromirror is set so that the colored light applied to the micromirror is turned on. The off state is a state in which the inclination of the micromirror is set so that the colored light applied to the micromirror is turned off.

  Hereinafter, light representing one pixel among a plurality of pixels constituting a frame (still image) is also referred to as “pixel light”. The color light irradiated to one micromirror is pixel light. Monochromatic image light is composed of k pixel lights.

  Hereinafter, the period in which the pixel light is on light is also referred to as “pixel on period”. Hereinafter, a period in which the pixel light is off light is also referred to as a “pixel off period”. In the following, each of the periods Tr, Tg, and Tb in FIG. 4 is also referred to as a “light irradiation target period”. In the following, each of the periods Tra, Tga, Tba is also referred to as a “video display period”. The video display period is a part of the light irradiation target period.

  The image display device 7 is irradiated with outgoing light (color light) over the light irradiation target period. Hereinafter, the emitted light (color light) irradiated on the image display device 7 over the light irradiation target period is also referred to as “emitted light Lz”.

  In addition, the image display device 7 is irradiated with emitted light (color light) for generating monochromatic video light over a video display period that is a part of the light irradiation target period. For example, over the period Tra, the image display device 7 is irradiated with red light for generating the video light Lr. Hereinafter, the emitted light (color light) irradiated to the image display device 7 over the video display period that is a part of the light irradiation target period is also referred to as “emitted light Lzi”. The outgoing light Lzi is a part of the outgoing light Lz.

  In the following, video data for expressing the video Ir is also referred to as “video data Irv”. In the following, video data for expressing the video Ig is also referred to as “video data Igv”. Hereinafter, the video data for expressing the video Ib is also referred to as “video data Ibv”.

  The image display device 7 is supplied with a video signal Vsg indicating video data for the image display device 7 to generate monochromatic video light during the video display period. For example, the image display device 7 is supplied with the video signal Vsg indicating the video data Irv for generating the video light Lr in the period Tra.

  For example, the image display device 7 modulates the red light applied to the image display device 7 over the period Tra based on the video signal Vsg indicating the video data Irv for generating the video light Lr in the period Tra. The video light Lr is generated.

  In the following, the time indicating the video display period is also referred to as “video display time”. Hereinafter, the time indicating the pixel on period is also referred to as “pixel on time”.

  The video display period includes a pixel on period and a pixel off period. The pixel on period is set in the range from 0 to the video display time. The pixel off period is a time obtained by subtracting the pixel on time from the video display time. Hereinafter, the ratio between the pixel on period and the pixel off period in the video display period is also referred to as a “light amount control ratio”.

  The image display device 7 generates monochromatic image light by performing the following luminance control processing on each of the k pixel lights respectively corresponding to the k micromirrors based on the k pixel data. To do.

  The brightness control process is a process for controlling one micromirror irradiated with pixel light to change the light amount control ratio. When the image display device 7 sets the magnitude of the light amount control ratio to, for example, any one of 256 kinds, the magnitude of the luminance of the pixel light is set to any one of 256 kinds. .

  The monochromatic image light generated by the image display device 7 is applied to the screen 10 via the projection lens 8.

  The image display device 7 sequentially performs the above-described processing on the red light, the green light, and the blue light that are color lights, thereby sequentially obtaining the video light Lr, the video light Lg, and the video light Lb that are monochromatic video lights. Generate. In the period Tfr of FIG. 4, the image light Lr, the image light Lg, and the image light Lb are sequentially irradiated onto the screen 10 through the projection lens 8.

  As a result, an image indicated by the monochromatic image light is displayed on the screen 10. That is, the screen light of the video display device Dp is irradiated with video light (monochromatic video light) obtained by modulating the outgoing light Lzi, which is a part of the outgoing light Lz, based on the original video (video data) indicated by the video signal Vsg. As a result, an image is displayed on the screen 10.

  Further, the monochromatic image light is generated using the outgoing light Lzi (color light). That is, the emitted light Lzi, which is a part of the emitted light Lz, is used to display an image on the screen 10 of the image display device Dp.

  Further, the image light Lr is applied to the screen 10 in the period Tra. The image light Lg is applied to the screen 10 during the period Tga. The image light Lb is applied to the screen 10 during the period Tba. As a result, a video Ic represented by the video Ir, the video Ig, and the video Ib is displayed on the screen 10.

  Hereinafter, the off-light indicating the red solid image is also referred to as “off-light Lnr”. In the following, the off-light indicating the green solid image is also referred to as “off-light Lng”. In the following description, the off-light indicating a blue solid image is also referred to as “off-light Lnb”.

  For example, when the image display device 7 irradiates red light to k micromirrors, the off-light Lnr is generated by setting the k micromirrors to an off state. The off light Lnr is generated during the period Trn in FIG. Therefore, the off-light Lnr is irradiated to the detection unit SN1 in the period Trn. That is, the image display device 7 sequentially generates the video light Lr and the off-light Lnr using red light in the period Tr.

  The off lights Lng and Lnb are also generated by a generation method similar to the above generation method of the off light Lnr. The off-light Lng is irradiated to the detection unit SN1 during the period Tgn. The off-light Lnb is irradiated to the detection unit SN1 in the period Tbn.

  The lengths of the periods Trn, Tgn, and Tbn are the same. Hereinafter, each of the periods Trn, Tgn, and Tbn is also referred to as an “off light detection period”. The off-light detection period is set to about 1/30 times the video display period, for example. For example, the period Trn that is the off-light detection period is set to about 1/30 times the period Tra that is the video display period.

  Hereinafter, each of the off lights Lnr, Lng, and Lnb is also referred to as “off light Ln”. The off-light Ln is light that is irradiated to the image display device 7 over an off-light detection period that is a part of the light irradiation target period. That is, the off-light Ln is another part of the emitted light Lz that is different from a part of the emitted light Lz (emitted light Lzi).

  The detection unit SN1 has a function of detecting tristimulus values XYZ (luminance and chromaticity) of light. Hereinafter, the tristimulus values XYZ are also simply referred to as “tristimulus values”. Tristimulus values are three values for expressing a color. The tristimulus value is a general value indicating a color, and a detailed description thereof will be omitted. Note that the luminance and chromaticity of the off-light Ln are specified by a general calculation using tristimulus values.

  The detection unit SN1 detects the tristimulus value of the off-light Ln each time the detection unit SN1 is irradiated with the off-light Ln (color light). Therefore, when the tristimulus value changes, it can be seen that both or one of the luminance and chromaticity of the off-light Ln has changed.

  The image display device 7 and the detection unit SN1 operate as described above. Therefore, even when a plurality of single-color image lights are sequentially irradiated on the screen 10, the detection unit SN1 can determine the tristimulus value of the off-light Ln with almost no influence from the ambient environment such as external light. To detect. Specifically, the detection unit SN1 detects the tristimulus value of the off light Ln for each off light Ln.

  Hereinafter, the tristimulus value of the off-light Lnr is also referred to as “tristimulus value DSTr”. Hereinafter, the tristimulus value of the off-light Lng is also referred to as “tristimulus value DSTg”. Hereinafter, the tristimulus value of the off-light Lnb is also referred to as “tristimulus value DSTb”. Hereinafter, each of the tristimulus values DSTr, DSTg, and DSTb is also simply referred to as “tristimulus value DST”.

  The detection unit SN1 transmits the tristimulus value DST of the off light Ln to the display characteristic calculation unit 15 every time the detection unit SN1 is irradiated with the off light Ln (color light).

  Hereinafter, the tristimulus value DST processed in the video display device 100m (master device) in the situation Stn is also referred to as “tristimulus value DSTm”. Hereinafter, the tristimulus values DST processed in the video display device 100s (slave device) in the situation Stn are also referred to as “tristimulus values DSTs”.

  Although details will be described later, the calculation unit 13 has a function of calculating target data Ct described later.

  The display characteristic calculation unit 15 performs processing described later based on the tristimulus value DST from the detection unit SN1.

  Hereinafter, the situation where the off-light Lnr is irradiated onto the screen 10 over the period Tra in FIG. 4 is also referred to as “situation StLra”. The situation StLra is a situation where a red solid image is temporarily displayed on the screen 10 over the period Tra. In the following, the tristimulus values on the screen 10 in the situation StLra are also referred to as “tristimulus values SCRr”. When the off-light detection period is, for example, about 1/30 times the video display period, the brightness of the screen 10 specified by the tristimulus value SCRr is 30 times the brightness of the off-light Lnr.

  In the following, a situation in which the off-light Lng is irradiated on the screen 10 over the period Tga in FIG. 4 is also referred to as “situation StLga”. In the following, the tristimulus values on the screen 10 in the situation StLga are also referred to as “tristimulus values SCRg”.

  In the following, the situation where the off-light Lnb is irradiated on the screen 10 over the period Tba of FIG. 4 is also referred to as “situation StLba”. Hereinafter, the tristimulus values on the screen 10 in the situation StLba are also referred to as “tristimulus values SCRb”.

  In the present embodiment, the tristimulus value SCRr in the situation Stn is measured in advance by the color measuring instrument in the state StLra generated in the situation Stn described above. The color measuring device is, for example, a color analyzer. Then, the coefficient Hr for calculating the tristimulus value SCRr in the situation Stn is specified in advance from the tristimulus value DSTr in the situation Stn. The coefficient Hr is, for example, the coefficient Hr for calculating the tristimulus value SCRr by multiplying the tristimulus value DSTr by the coefficient Hr.

  In the present embodiment, the tristimulus value SCRg in the situation Stn is measured in advance by the color measuring device in the situation in which the situation StLrg is generated in the situation Stn. Then, like the coefficient Hr, the coefficient Hg for calculating the tristimulus value SCRg in the situation Stn is specified in advance by multiplying the tristimulus value DSTg in the situation Stn by the coefficient Hg.

  In the present embodiment, the tristimulus value SCRb in the situation Stn is previously measured by the color measuring device in the situation where the situation StLrb is generated in the situation Stn. Similarly to the coefficient Hr, the coefficient Hb for calculating the tristimulus value SCRb in the situation Stn is specified in advance by multiplying the tristimulus value DSTb in the situation Stn by the coefficient Hb.

  The coefficients Hr, Hg, and Hb are stored in advance in the display characteristic calculation unit 15.

  The above processing is performed for each video display device Dp in advance. Therefore, the display characteristic calculation unit 15 of each video display device Dp previously stores coefficients Hr, Hg, and Hb corresponding to the characteristics of the light source 3 of the video display device Dp.

  Hereinafter, red or red is also referred to as “R”. In the following, green or green is also referred to as “G”. In the following, blue or blue is also referred to as “B”. In the following, white or white is also referred to as “W”.

  Hereinafter, the data indicating the tristimulus values SCRr, SCRg, and SCRb is also referred to as “tristimulus value data SCR”. That is, the tristimulus value data SCR indicates tristimulus values corresponding to R, G, and B, respectively. Therefore, the tristimulus value data SCR is expressed by a 3 × 3 matrix indicating nine elements.

  Hereinafter, the tristimulus value data SCR processed in the video display device 100m (master device) in the situation Stn is also referred to as “tristimulus value data SCRm”. Hereinafter, the tristimulus value data SCR processed in the video display device 100s (slave device) in the situation Stn is also referred to as “tristimulus value data SCRs”.

  The tristimulus value data SCRm is expressed as the following equation (1).

  Xrm, Yrm, Zrm, Xgm, Ygm, Zgm, Xbm, Ybm, and Zbm in Expression (1) are tristimulus values processed by the video display device 100m in the situation Stn. Xrm, Yrm, and Zrm are tristimulus values SCRr. Xgm, Ygm, and Zgm are tristimulus values SCRg. Xbm, Ybm, and Zbm are tristimulus values SCRb.

  Further, the tristimulus value data SCRs is expressed as in the following equation (2).

  In Expression (2), Xrs, Yrs, Zrs, Xgs, Ygs, Zgs, Xbs, Ybs, and Zbs are tristimulus values processed by the video display device 100s in the situation Stn. Xrs, Yrs, and Zrs are tristimulus values SCRr. Xgs, Ygs, and Zgs are tristimulus values SCRg. Xbs, Ybs, and Zbs are tristimulus values SCRb.

(Operation of multi-screen display device)
Next, processing performed by the multi-screen display device 1000 in the above-described situation Stn (hereinafter referred to as “video correction processing N” will be described. The situation Stn is, for example, a situation in which a new multi-screen display device 1000 is installed at a location desired by the user. This is an initial situation where the use of the multi-screen display device 1000 is started.

  In the present embodiment, the operation mode of each of the video display devices 100m and 100s in the situation Stn is set to the luminance reduction mode. Therefore, in each of the video display devices 100m and 100s, the light source control unit 14 controls each light source 3 so that each light source 3 emits the emitted light having the luminance indicating the above-described suppression value in the situation Stn. . The suppression value is a value that is v times the maximum luminance value YMx of each light source 3 in the situation Stn. Therefore, the brightness value of the emitted light of each light source 3 provided in each of the video display devices 100m and 100s is set to a suppression value.

  In the present embodiment, the luminance (intensity) of each of red light, green light, and blue light, which are color lights, is expressed as a real number in the range of 0 to 1. For example, the maximum luminance of red light is 1. The luminance (intensity) of each of the video lights Lr, Lg, and Lb that are monochromatic video lights is expressed by a real number in the range of 0 to 1. For example, the maximum value of the luminance of the video light Lr is 1.

  FIG. 5 is a flowchart of video correction processing N according to Embodiment 1 of the present invention. The video correction process N includes a video correction process Nm performed by the video display apparatus 100m (master apparatus) and a video correction process Ns performed by the video display apparatus 100s (slave apparatus).

  Here, the following premise Pr1 is considered. In the premise Pr1, in each of the video display devices 100m and 100s in the situation Stn, the off-light Lnr, Lng, and Lnb, which are the off-light Ln, are sequentially irradiated to the detection unit SN1. In the premise Pr1, the maximum luminance value YMx of the emitted light from each light source 3 is the value Va. The value Va is a real number larger than 0.

  Next, the video correction process N in the premise Pr1 will be described. In the video correction process Nm performed by the video display device 100m, first, the process of step S110m is performed.

  In step S110m, a DSTm acquisition process is performed. In the DSTm acquisition process, the detection unit SN1 detects tristimulus values DSTr, DSTg, and DSTb that respectively correspond to the off lights Lnr, Lng, and Lnb irradiated to the detection unit SN1. Then, the detection unit SN1 sequentially transmits the tristimulus values DSTr, DSTg, and DSTb, which are the tristimulus values DSTm, to the display characteristic calculation unit 15.

  In step S120m, an SCRm calculation process is performed. In the SCRm calculation process, the display characteristic calculation unit 15 calculates the tristimulus values SCRr, SCRg, and SCRrb based on the tristimulus values DSTr, DSTg, and DSTb and the coefficients Hr, Hg, and Hb described above.

  Specifically, the display characteristic calculation unit 15 calculates tristimulus values SCRr, SCRg, and SCRrb by multiplying the tristimulus values DSTr, DSTg, and DSTb by coefficients Hr, Hg, and Hb, respectively. Then, the display characteristic calculation unit 15 stores the above-described tristimulus value data SCRm indicating the tristimulus values SCRr, SCRg, and SCRrb in the memory 12 via the control unit 11.

  In the video correction process Ns performed by the video display device 100s, first, the process of step S110s is performed.

  In step S110s, DSTs acquisition processing is performed. In the DSTs acquisition process, the detection unit SN1 detects tristimulus values DSTr, DSTg, and DSTb that respectively correspond to the off lights Lnr, Lng, and Lnb irradiated to the detection unit SN1. Then, the detection unit SN1 sequentially transmits the tristimulus values DSTr, DSTg, and DSTb, which are the tristimulus values DSTs, to the display characteristic calculation unit 15.

  In step S120s, an SCRs calculation process is performed. In the SCRs calculation process, the display characteristic calculation unit 15 calculates the tristimulus values SCRr, SCRg, and SCRrb based on the tristimulus values DSTr, DSTg, and DSTb and the coefficients Hr, Hg, and Hb described above.

  Specifically, the display characteristic calculation unit 15 calculates tristimulus values SCRr, SCRg, and SCRrb by multiplying the tristimulus values DSTr, DSTg, and DSTb by coefficients Hr, Hg, and Hb, respectively. Then, the display characteristic calculation unit 15 stores the above-described tristimulus value data SCRs indicating the tristimulus values SCRr, SCRg, and SCRrb in the memory 12 via the control unit 11.

  In step S125s, SCRs transmission processing is performed. In the SCRs transmission process, the control unit 11 transmits the tristimulus value data SCRs to the video display device 100m via the communication cable 16. Thereby, the control unit 11 of the video display device 100m receives the tristimulus value data SCRs and stores the tristimulus value data SCRs in the memory 12.

  Hereinafter, the target luminance is also referred to as “target luminance”. In the following, the target chromaticity is also referred to as “target chromaticity”. Hereinafter, data for specifying the target luminance and the target chromaticity is also referred to as “target data Ct”. In the following, the target tristimulus value is also referred to as “target tristimulus value”.

  In the following, in the situation Stn, the target tristimulus value on the screen 10 in a state in which the situation StLra is generated is also referred to as “tristimulus value Ctr”. In the following, in the situation Stn, the target tristimulus value on the screen 10 in a state where the situation StLga is generated is also referred to as “tristimulus value Ctg”. In the following, in the situation Stn, the target tristimulus value on the screen 10 in a state where the situation StLba is generated is also referred to as “tristimulus value Ctb”.

  The target data Ct is data indicating tristimulus values Ctr, Ctg, Ctb. That is, the target data Ct indicates tristimulus values corresponding to R, G, and B, respectively. Therefore, the target data Ct is expressed by a 3 × 3 matrix indicating nine elements. The target data Ct is expressed as the following formula (3).

  Xtr, Ytr, Ztr in the equation (3) are tristimulus values Ctr. Xtg, Ytg, and Ztg are tristimulus values Ctg. Xtb, Ytb, and Ztb are tristimulus values Ctb.

  In the following, the target chromaticity that can be expressed in common on the screen 10 of the video display device Dp by each video display device Dp constituting the multi-screen display device 1000 under the situation Stn is referred to as “target chromaticity ctn”. "

  After the process of step S125s described above, the process of step S130m is performed in the video correction process Nm.

  In step S130m, Ct calculation processing is performed. Although details will be described later in the Ct calculation process, the calculation unit 13 of the video display device 100m calculates the target data Ct of Expression (3) based on the tristimulus value data SCRm and the tristimulus value data SCRs.

  FIG. 6 is a diagram for explaining a method of calculating the target chromaticity. FIG. 6 shows the u'v 'chromaticity diagram. The u'v 'chromaticity diagram is a CIE 1976 UCS chromaticity diagram. Hereinafter, the coordinates in the u′v ′ chromaticity diagram are also referred to as “chromaticity coordinates” or “u′v ′ coordinates”.

  In the u′v ′ chromaticity diagram of FIG. 6, triangles TRm and TRs and a common region triangle TRcm are shown as an example. Note that the shapes and positions of the triangles TRm and TRs are examples and positions, respectively.

  A triangle TRm indicates a color range (color reproduction range) that can be expressed on the screen 10 by light emitted from each light source 3 included in the video display device 100m. The three vertices of the triangle TRm are chromaticity CPrm, chromaticity CPgm, and chromaticity CPbm.

  A triangle TRs indicates a color range (color reproduction range) that can be expressed on the screen 10 by the light emitted from each light source 3 included in the video display device 100s. The three vertices of the triangle TRs are a chromaticity CPrs, a chromaticity CPgs, and a chromaticity CPbs.

  In the following, the region showing red in the u′v ′ chromaticity diagram is also referred to as “primary color region Rr”. In the following, a region indicating green in the u′v ′ chromaticity diagram is also referred to as a “primary color region Rg”. In the following, a region indicating blue in the u′v ′ chromaticity diagram is also referred to as a “primary color region Rb”. Hereinafter, each of the primary color regions Rr, Rg, and Rb is also simply referred to as a “primary color region”.

  Hereinafter, each of the triangles TRm and TRs is also referred to as “target triangle TR”. The target triangle TR includes three acute angles (corners). Hereinafter, the acute angle portion where the apex of the acute angle portion exists in the primary color region Rr is also referred to as “acute angle portion r”. For example, the acute angle portion r of the triangle TRm is an acute angle portion where a chromaticity coordinate CPrm that is the vertex of the acute angle portion r exists.

  In the following, the acute angle portion where the apex of the acute angle portion exists in the primary color region Rg is also referred to as “acute angle portion g”. In the following, the acute angle portion where the apex of the acute angle portion exists in the primary color region Rb is also referred to as “acute angle portion b”.

  The common region triangle TRcm is a triangle indicating a common region included in each of the triangle TRm and the triangle TRs. The three vertices of the common region triangle TRcm are chromaticity CPrcm, chromaticity CPgcm (chromaticity CPgs), and chromaticity CPbcm. The chromaticity CPgcm is the same as the chromaticity CPgs. The common area triangle TRcm indicates a range of colors that can be expressed in common on the screen 10 of the video display device Dp by the video display devices Dp (video display devices 100m and 100s).

  Here, it is assumed that the color reproduction range by the emitted light of each light source 3 in the situation Stn included in the video display device 100m is a triangle TRm in FIG. 6 as an example. Further, it is assumed that the color reproduction range by the emitted light of each light source 3 in the situation Stn included in the video display device 100m is, for example, the triangle TRs in FIG. In addition, the range of colors that can be commonly expressed on the screen 10 of the video display device Dp by each video display device Dp (video display devices 100m and 100s) under the situation Stn is, as an example, common to FIG. Assume a region triangle TRcm.

  In this case, in the Ct calculation process, the target data Ct is calculated as follows. First, the calculation unit 13 calculates chromaticity CPrm, CPgm, CPbm using the tristimulus values SCRr, SCRg, SCRrb of the tristimulus value data SCRm.

  For example, the chromaticity CPrm is the chromaticity in the u′v ′ chromaticity diagram calculated from the tristimulus values SCRr (Xrm, Yrm, Zrm). Note that a method for calculating the chromaticity in the u′v ′ chromaticity diagram from the tristimulus values is a general method, and thus the description thereof is omitted. Similar to the chromaticity CPrm, the chromaticities CPgm and CPbm in the u′v ′ chromaticity diagram are calculated by the tristimulus values SCRg and SCRrb, respectively.

  Then, the calculation unit 13 plots the chromaticities CPrm, CPgm, and CPbm on the u′v ′ chromaticity diagram of FIG. 6. Thereby, calculation part 13 specifies triangle TRm.

  Further, the calculation unit 13 uses the tristimulus values SCRr, SCRg, and SCRrb of the tristimulus value data SCRs in the same manner as the method for specifying the triangle TRm, and uses the chromaticity CPrs, CPgs, CPbs in the u′v ′ chromaticity diagram. Is calculated. Then, the calculation unit 13 plots the chromaticities CPrs, CPgs, and CPbs on the u′v ′ chromaticity diagram of FIG. 6. Thereby, the calculation part 13 specifies triangle TRs.

  Next, the calculation unit 13 specifies the common region triangle TRcm based on the triangle TRm and the triangle TRs shown in the u′v ′ chromaticity diagram according to the following rules Ru1 and Ru2.

  The rule Ru1 is a rule that specifies the chromaticity of an intersection existing in the intersecting state when the acute angle portion of each target triangle TR is in the intersecting state in the primary color region. The said crossing state is a state in which both or one of the two sides of the acute angle portion of the target triangle TR intersects with one or both of the two sides of the acute angle portion of another target triangle TR. The intersection existing in the intersecting state is an intersection between the edge of the acute angle portion of the target triangle TR and the edge of the acute angle portion of another target triangle TR in the intersection state.

  The rule Ru1 is a rule that specifies the chromaticity of the intersection closest to the white chromaticity among the plurality of intersections when there are a plurality of intersections.

  For example, in the primary color region Rr of FIG. 6, one side of the acute angle portion r of the triangle TRm intersects with one side of the acute angle portion r of the triangle TRs. Therefore, the calculation unit 13 specifies the chromaticity CPrcm that is the intersection of one side of the acute angle portion r of the triangle TRm and one side of the acute angle portion r of the triangle TRs according to the rule Ru1. The chromaticity CPbcm is also specified by the same method as the chromaticity CPrcm.

  When the vertex of the acute angle portion of the target triangle TR is included in the acute angle portion of another target triangle TR in the primary color region, the rule Ru2 is the acute angle portion closest to the white chromaticity among the acute angle portions of each target triangle TR. It is a rule that specifies the chromaticity of the vertex of.

  For example, in the primary color region Rg of FIG. 6, the apex (chromaticity CPgs) of the acute angle portion g of the triangle TRs is included in the acute angle portion g of the triangle TRm. Therefore, according to the rule Ru2, the calculation unit 13 has the chromaticity (color) of the apex of the acute angle part g of the triangle TRs that is closest to the white chromaticity among the acute angle part g of the triangle TRm and the acute angle part g of the triangle TRs. Degree CPgs).

  Then, the calculation unit 13 plots the chromaticities CPrcm, CPgs (CPgcm), and CPbcm on the u′v ′ chromaticity diagram of FIG. 6. Thereby, the calculation unit 13 specifies the common region triangle TRcm.

  The specified common region triangle TRcm indicates a range of colors that can be commonly expressed on the screen 10 of the video display device Dp by each video display device Dp (video display devices 100m and 100s) under the situation Stn. .

  The common region triangle TRcm may be specified by a method similar to the method for obtaining the common region triangle disclosed in Japanese Patent No. 4823660, for example. In this method, the calculation unit 13 uses the chromaticities CPrm, CPgm, CPbm of the triangle TRm and the chromaticities CPrs, CPgs, CPbs of the triangle TRs to calculate the chromaticities CPrcm, CPgcm, CPbcm.

  Next, the calculation unit 13 calculates the luminance with the smallest value among the luminance of the tristimulus value SCRr and the luminance of the tristimulus value data SCRs as the target luminance.

  Hereinafter, the target luminance of R in the situation Stn is also referred to as “target luminance Ytr” or “Ytr”. In the following, the target luminance of G in the situation Stn is also referred to as “target luminance Ytg” or “Ytg”. In the following description, the target luminance of B in the situation Stn is also referred to as “target luminance Ytb” or “Ytb”.

  Specifically, the calculation unit 13 calculates the lowest luminance among the Yrm (luminance) of the tristimulus value SCRr and the Yrs (luminance) of the tristimulus value data SCRs as the target luminance Ytr. For example, when Yrm is smaller than Yrs, the calculation unit 13 calculates the Yrm as the target luminance Ytr.

  The calculation unit 13 calculates either Ygm or Ygs as the target luminance Ytg by the same method as the target luminance Ytr. The target brightness Ytb is calculated using Ybm and Ybs in the same manner as the target brightness Ytr.

  Next, the calculation unit 13 uses the calculated chromaticities (chromaticity CPrcm, CPgs (CPgcm), CPbcm) and the calculated target luminances Ytr, Ytg, Ytb in the common region triangle TRcm to use the tristimulus. Calculate the value. Each of the target luminances Ytr, Ytg, Ytb is one stimulus value in the tristimulus values.

  Specifically, the calculation unit 13 calculates Xtr and Ztr of the tristimulus values Ctr from the target luminance Ytr and the coordinates of the chromaticity CPrcm in the u′v ′ chromaticity diagram. Since the method of calculating Xtr and Ztr using the target luminance Ytr and the coordinates of the chromaticity CPrcm in the u′v ′ chromaticity diagram is a general method, description thereof is omitted. Thereby, tristimulus values Ctr (Xtr, Ytr, Ztr) are calculated.

  Further, the calculation unit 13 calculates the above-described tristimulus values Ctg (Xtg, Ytg, Ztg) using the target luminance Ytg and the chromaticity CPgs (CPgcm) by the same method as the tristimulus values Ctr. Further, the calculation unit 13 calculates the above-described tristimulus values Ctb (Xtb, Ytb, Ztb) using the target luminance Ytb and the chromaticity CPbcm by the same method as the tristimulus values Ctr.

  And the calculation part 13 calculates the target data Ct of Formula (3) which shows tristimulus value Ctr, Ctg, Ctb. Thus, the calculation of the target data Ct ends.

  In the following, the target luminance that can be expressed in common on the screen 10 of the video display device Dp by each video display device Dp constituting the multi-screen display device 1000 under the situation Stn is also referred to as “target luminance Yt”. Say. Each of the target luminances Ytr, Ytg, Ytb of the calculated target data Ct is the target luminance Yt. That is, the target data Ct is also data for specifying the target luminance Yt.

  Further, as described above, the target chromaticity that can be commonly expressed on the screen 10 of the video display device Dp by the video display devices Dp constituting the multi-screen display device 1000 under the situation Stn is expressed as “target chromaticity”. Also referred to as “chromaticity ctn”.

  Hereinafter, the target chromaticity of R in the situation Stn is also referred to as “target chromaticity ctr”. In the following, the target chromaticity of G in the situation Stn is also referred to as “target chromaticity ctg”. In the following, the target chromaticity of B in the situation Stn is also referred to as “target chromaticity ctb”. Each of the target chromaticities ctr, ctg, and ctb is the target chromaticity ctn.

  It should be noted that the target chromaticity ctr in the u′v ′ chromaticity diagram can be obtained by a general conversion equation using Xtr, Ytr, Ztr of the target data Ct. Further, the target chromaticity ctg in the u′v ′ chromaticity diagram can be obtained from the target data Ct by Xtg, Ytg, and Ztg, similarly to the target chromaticity ctr. Further, the target chromaticity ctb in the u′v ′ chromaticity diagram can be obtained from Xtb, Ytb, and Ztb of the target data Ct, similarly to the target chromaticity ctr. That is, the target data Ct is also data for specifying the target chromaticity ctn.

  The target data Ct is calculated using each off-light Ln of each video display device Dp in the situation Stn. That is, the calculation unit 13 calculates target data Ct based on each off light Ln of each video display device Dp in the situation Stn.

  After step S130m, the process of step S131m is performed.

  In the following, the target tristimulus value of W (white) in the situation Stn is expressed as “target tristimulus value Ctw (Xtw, Ytw, Ztw)” or “target tristimulus value Ctw”.

  In step S131m, the calculation unit 13 calculates the target tristimulus value Ctw using the target data Ct. The target tristimulus value Ctw is calculated by substituting each tristimulus value of the target data Ct into the following equation (4).

  In step S140m, a Ct transmission process is performed. In the Ct transmission process, the control unit 11 transmits the calculated target data Ct to the video display device 100s via the communication cable 16. Accordingly, the control unit 11 of the video display device 100s receives the target data Ct.

  In the video display device 100s, the process of step S141s is performed. In step S141s, a Ct storage process is performed. In the Ct storage process, the control unit 11 stores the received target data Ct in the memory 12.

  In the video display device 100m, the process of step S141m is performed. In step S141m, a Ct storage process is performed. In the Ct storage process, the control unit 11 stores the target data Ct in the memory 12.

  In step S150m, a CSCm calculation process is performed. Although details will be described later in the CSCm calculation process, the control unit 11 calculates the correction coefficient CSCm based on the target data Ct corresponding to the situation Stn. That is, the control unit 11 is a calculation unit that calculates the correction coefficient CSCm.

  The correction coefficient CSCm is a coefficient indicating the coefficients RRm, RGm, RBm, GRm, GGm, GBm, BRm, BGm, and BBm in a 3 × 3 matrix.

  Although details will be described later, the correction coefficient CSCm is calculated using the following equation (5).

  In equation (5), SCRm is the tristimulus value data SCRm of equation (1). Ct is the target data Ct of Expression (3). Further, “x” in Expression (5) indicates a matrix product. Note that “x” shown in the following equation also indicates a matrix product. “−1” in Expression (5) is for making the matrix associated with the “−1” an inverse matrix. As described above, the expression (5) is expressed by the following expression (6).

  Hereinafter, an image generated from the color light and the image data indicated by the image signal Vsg and displayed on the screen 10 is also referred to as a “display target image”. In the following, the display target video in the situation Stn is also referred to as “display target video Imn”. The display target video Imn is a video to be displayed on the screen 10 of each video display device Dp under the situation Stn.

  Hereinafter, the corrected pixel data obtained by multiplying the pixel data indicated by the video data by the correction coefficient CSCm is also referred to as “corrected pixel data”. In the following, video data indicating k correction pixel data is also referred to as “corrected video data”. Hereinafter, the video signal Vsg indicating the corrected video data is also referred to as a “corrected video signal Vsga”.

  In the situation Stn, the display target video Imn is obtained by performing the process using the k correction pixel data corresponding to the video data.

  The correction coefficient CSCm indicates the intensity of each component of the tristimulus values SCRr, SCRg, SCRb. The correction coefficient CSCm is a coefficient for correcting the luminance and chromaticity of the original video indicated by each video data indicated by the video signal Vsg.

  The correction coefficient CSCm is a coefficient for making the luminance of the display target video Imn the same or equivalent to the target luminance Yt and making the chromaticity of the display target video Imn the same or equivalent to the target chromaticity ctn. That is, the correction coefficient CSCm minimizes the absolute value of the difference between the luminance of the display target video Imn and the target luminance Yt in the situation Stn, and the difference between the chromaticity of the display target video Imn and the target chromaticity ctn in the situation Stn. Is a coefficient for minimizing the absolute value of.

  Therefore, the correction coefficient CSCm is obtained by back calculation for setting the luminance and chromaticity of the display target video Imn obtained using the k correction pixel data as the target luminance Yt and the target chromaticity ctn, respectively. Expressions indicating the reverse calculation are the above-described expressions (5) and (6).

  In Expression (6), RRm indicates the luminance (intensity) of the off-light Lnr alone when the screen 10 is irradiated with the off-light Lnr. In the following, luminance is also expressed as intensity. RGm indicates the intensity of the off-light Lng mixed with the off-light Lnr irradiated on the screen 10. RBm indicates the intensity of the off-light Lnb mixed with the off-light Lnr irradiated on the screen 10.

  GRm indicates the intensity of the off-light Lnr mixed with the off-light Lng irradiated on the screen 10. GGm indicates the intensity of the off light Lng alone when the screen 10 is irradiated with the off light Lng. GBm indicates the intensity of the off-light Lnb mixed with the off-light Lng irradiated on the screen 10.

  BRm indicates the intensity of the off-light Lnr mixed with the off-light Lnb irradiated on the screen 10. BGm indicates the intensity of the off-light Lng mixed with the off-light Lnb irradiated on the screen 10. BBm indicates the intensity of the off light Lnb alone when the screen 10 is irradiated with the off light Lnb.

  The values of RRm, RGm, RBm, GRm, GGm, GBm, BRm, BGm, and BBm are set so as to satisfy the following expressions (7), (8), and (9).

  If the equations (7) to (9) are not satisfied, the following problems occur. The inconvenience is that the white tristimulus value obtained by simply mixing the tristimulus values Ctr, Ctg, and Ctb of the video display device 100m in the situation Stn is displayed as the target tristimulus value Ctw. This is a problem that (Xtw, Ytw, Ztw) does not occur.

  In consideration of the above, in the CSCm calculation process in step S150m, specifically, the control unit 11 calculates Equation (6) by substituting tristimulus value data SCRm and target data Ct into Equation (5). . Thereby, the control part 11 calculates the correction coefficient CSCm. Then, the control unit 11 stores the correction coefficient CSCm in the memory 12.

  In step S160m, a correction process m is performed. In the correction process m, the control unit 11 corrects the luminance and chromaticity of the original video indicated by each of the video data Irv, Igv, and Ibv indicated by the video signal Vsg based on the correction coefficient CSCm, thereby displaying the display target video Imn. Is a process for correcting the luminance and chromaticity of the image.

  Specifically, the control unit 11 performs a calculation for correcting the luminance and chromaticity of the original video indicated by the video data. The control unit 11 performs multiplication processing for sequentially multiplying the k pieces of pixel data (Pr, Pg, Pb) indicated by the video data by the correction coefficient CSCm.

  In the multiplication process, the control unit 11 multiplies pixel data (Pr, Pg, Pb) represented by a matrix of 1 column and 3 rows by a correction coefficient CSCm. Thereby, corrected video data indicating k corrected pixel data is obtained. Multiplication processing is sequentially performed on the video data Irv, Igv, and Ibv.

  Hereinafter, the corrected video data obtained from the video data Irv is also referred to as “corrected video data Irva”. Hereinafter, the corrected video data obtained from the video data Igv is also referred to as “corrected video data Igva”. Hereinafter, the corrected video data obtained from the video data Ibv is also referred to as “corrected video data Ibva”.

  Thereby, a corrected video signal Vsga indicating the corrected video data Irva, Igva, Ibva is obtained.

  Then, the control unit 11 transmits the corrected video signal Vsga to the image display device 7.

  The image display device 7 generates monochromatic video light by modulating the color light based on the corrected video signal Vsga, as in the above-described processing. For example, the image display device 7 generates the video light Lr by modulating red light based on the corrected video data Irva. Then, the image light Lr is applied to the screen 10, whereby the image Ir that is the display image Imn is displayed on the screen 10.

  The image display device 7 performs a process similar to the process using the video data Irva for the corrected video data Igva and Ibva. Thereby, the video Ir, the video Ig, and the video Ib are displayed on the screen 10 in order. As a result, the video Ic is expressed on the screen 10. The video Ic is a video generated using red light, green light, and blue light in the situation Stn.

  The video display device 100s performs step S150s after step S141s.

  In step S150s, a CSCs calculation process is performed. Since the CSCs calculation process is the same as the CSCm calculation process, detailed description thereof is omitted. A brief description is given below.

  In the CSCs calculation process, the control unit 11 calculates the correction coefficient CSCs based on the target data Ct corresponding to the situation Stn. That is, the control unit 11 is a calculation unit that calculates the correction coefficient CSCs.

  The correction coefficient CSCs is a coefficient indicating the coefficients RRs, RGs, RBs, GRs, GGs, GBs, BRs, BGs, and BBs in a matrix of 3 rows and 3 columns. The correction coefficient CSCs is calculated using the following equation (10).

  By substituting equation (2) into equation (10), equation (10) is expressed by equation (11) below.

  The coefficients RRs, RGs, RBs, GRs, GGs, GBs, BRs, BGs, BBs have the same role as the coefficients RRm, RGm, RBm, GRm, GGm, GBm, BRm, BGm, BBm, respectively.

  The coefficients RRs, RGs, RBs, GRs, GGs, GBs, BRs, BGs, and BBs are obtained by replacing “m” with “s” in each of the equations (7), (8), and (9). Set to satisfy the expression.

  In step S150s, the control unit 11 calculates Formula (11) in which the tristimulus value data SCRs and the target data Ct are substituted into Formula (10). Thereby, the control unit 11 calculates the correction coefficient CSCs. Then, the control unit 11 stores the correction coefficient CSCs in the memory 12. The correction coefficient CSCs has the same function and role as the correction coefficient CSCm.

  In step S160s, a correction process s is performed. Since the correction process s is a process in which “correction coefficient CSCm” is replaced with “correction coefficient CSCs” in the description of the correction process m, detailed description will not be repeated. The image Ir, the image Ig, and the image Ib are sequentially displayed on the screen 10 by the correction process s. As a result, the video Ic is expressed on the screen 10.

  As described above, the video correction process Nm (correction process m) and the video correction process Ns (correction process s) are performed. Thereby, each of the video display devices 100m and 100s in the situation Stn minimizes the absolute value of the difference between the luminance of the display target video Imn and the target luminance Yt in the situation Stn based on the correction coefficient, and the display target video. A correction process (correction process m or correction process s) that minimizes the absolute value of the difference between the chromaticity of Imn and the target chromaticity ctn in the situation Stn is performed.

  That is, in each of the video display devices 100m and 100s in the situation Stn, the luminance of the display video Imn is the same or equivalent to the target luminance Yt, and the chromaticity of the display target video Imn is the same or equivalent to the target chromaticity ctn. Become. That is, in each of the video display devices 100m and 100s in the situation Stn, the luminance and chromaticity of the display target video Imn are close to the target luminance Yt and the target chromaticity ctn, respectively.

  Each light source 3 included in each of the video display devices 100m and 100s has a characteristic that the light source 3 is deteriorated as the cumulative drive time becomes longer in a state where the cumulative drive time is longer than the initial time below. Therefore, the luminance and chromaticity of the video displayed on each screen 10 constituting the multi-screen 10A gradually change from the state in the situation Stn.

  That is, the luminance and chromaticity of the video displayed on each screen 10 constituting the multi-screen 10A gradually change from the target luminance Yt and the target chromaticity ctn adjusted in the situation Stn.

  Next, the processing performed by the multi-screen display device 1000 in the situation Sti (hereinafter, “video correction processing I” will be described. As described above, the situation Sti represents each video display device Dp constituting the multi-screen display device 1000. The accumulated drive time of each light source 3 included in the time is a time longer than the reference time i.

  The video correction process I is a process for making the brightness and chromaticity of W that can be expressed in the situation Sti equal to the brightness and chromaticity obtained from the target tristimulus value Ctw adjusted in the situation Stn. The video correction process I is a process for equalizing the luminance and chromaticity between the screens 10 for R, G, B, or for the mixed colors of R, G, B.

  Hereinafter, the tristimulus value DST processed in the video display device 100m (master device) in the situation Sti is also referred to as “tristimulus value DSTmi”. Hereinafter, the tristimulus value DST processed in the video display device 100s (slave device) in the situation Sti is also referred to as “tristimulus value DSTsi”.

  Hereinafter, the tristimulus value data SCR processed in the video display device 100m (master device) in the situation Sti is also referred to as “tristimulus value data SCRmi”. Hereinafter, the tristimulus value data SCR processed in the video display device 100s (slave device) in the situation Sti is also referred to as “tristimulus value data SCRsi”.

  The tristimulus value data SCRmi is expressed as the following equation (12).

  Xrmi, Yrmi, Zrmi, Xgmi, Ygmi, Zgmi, Xbmi, Ybmi, Zbmi in the expression (12) are tristimulus values processed by the video display device 100m in the situation Sti. Xrmi, Yrmi, Zrmi are tristimulus values SCRr obtained by multiplying the tristimulus value DSTr by a coefficient Hr. Xgmi, Ygmi, and Zgmi are tristimulus values SCRg obtained by multiplying the tristimulus value DSTg by a coefficient Hg. Xbmi, Ybmi, and Zbmi are tristimulus values SCRb obtained by multiplying the tristimulus value DSTb by a coefficient Hb.

  Further, the tristimulus value data SCRsi is expressed as in the following equation (13).

  In Expression (13), Xrsi, Yrsi, Zrsi, Xgsi, Ygsi, Zgsi, Xbsi, Ybsi, Zbsi are tristimulus values processed by the video display device 100s in the situation Sti. Xrsi, Yrsi, Zrsi are tristimulus values SCRr obtained by multiplying the tristimulus value DSTr by a coefficient Hr. Xgsi, Ygsi, Zgsi are tristimulus values SCRg obtained by multiplying the tristimulus value DSTg by a coefficient Hg. Xbsi, Ybsi, Zbsi are tristimulus values SCRb obtained by multiplying the tristimulus value DSTb by a coefficient Hb.

  In the present embodiment, immediately before the video correction process I is started, the operation modes of the video display devices 100m and 100s in the situation Sti are set to the luminance reduction mode.

  FIG. 7 is a flowchart of video correction processing I according to Embodiment 1 of the present invention. The video correction process I includes a video correction process Im performed by the video display apparatus 100m (master apparatus) and a video correction process Is performed by the video display apparatus 100s (slave apparatus).

  In FIG. 7, the processing with the same step number as the step number of FIG. 5 is performed in the same manner as the processing described in the video correction processing Nm and video correction processing Ns, and therefore detailed description will not be repeated. The following description will focus on differences from the video correction process Nm and the video correction process Ns.

  Here, the following premise Pr2 is considered. In the premise Pr2, in each of the video display devices 100m and 100s in the situation Sti, the off-light Lnr, Lng, and Lnb, which are the off-light Ln, are sequentially irradiated to the detection unit SN1.

  In the premise Pr2, the maximum luminance value YMx of the emitted light of each light source 3 included in each of the video display devices 100m and 100s in the above-described situation Stn is the value Va. The value Va is a real number larger than 0.

  In the premise Pr2, the maximum luminance value YMx of the emitted light of each light source 3 included in each of the video display devices 100m and 100s in the above-described situation Sti is the value Vb. The value Vb is a real number larger than 0. The value Vb is smaller than the value Va.

  Hereinafter, the target data Ct calculated by the above-described Ct calculation process (S130m) in the above-described situation Stn is also referred to as “calculated target data Ct”. In the following, when the calculation target data Ct is calculated, the suppression value set to the luminance value of the emitted light of each light source 3 included in each of the video display devices 100m and 100s in the situation Stn is expressed as “suppression Also referred to as “value Nn”.

  In the premise Pr2, target data Ct is stored in the memory 12 included in each of the video display devices 100m and 100s. In the premise Pr2, the target data Ct stored in the memory 12 included in each of the video display devices 100m and 100s is the above-described calculated target data Ct.

  In the following, each of Ytr, Ytg, Ytb indicated by the calculation target data Ct is expressed as “Yt”. Yt is the luminance of the video displayed on the screen 10 in the situation Stn. In the following, each of the aforementioned Yrmi, Ygmi, Ybmi, Yrsi, Ygsi, Yrsi is also expressed as “Yi”. Yi is the luminance of the video displayed on the screen 10 of each of the video display devices 100m and 100s in the situation Sti.

  In the assumption Pr2, the calculation target data Ct is data calculated in a state where the suppression value Nn is smaller than the value Va and equal to or less than the value Vb.

  Further, in the premise Pr2, immediately before the video correction process I is started, in each of the video display devices 100m and 100s, the light source control unit 14 satisfies Yi ≧ Yt, and in the situation Sti, the value Vb or less. In addition, each light source 3 is controlled so that each light source 3 emits the emitted light having a luminance indicating a value equal to or greater than the suppression value Nn.

  Next, the video correction process I in the premise Pr2 will be described. In the video correction process Im performed by the video display device 100m, first, the process of step S110mA is performed.

  In step S110 mA, the DSTmi acquisition process is performed in the same manner as the DSTm acquisition process of the video correction process Nm. Accordingly, the detection unit SN1 sequentially transmits the tristimulus values DSTr, DSTg, and DSTb, which are the tristimulus values DSTmi, to the display characteristic calculation unit 15.

  In step S120 mA, an SCRmi calculation process is performed. In the SCRmi calculation process, the display characteristic calculation unit 15 multiplies the received tristimulus values DSTr, DSTg, and DSTb by coefficients Hr, Hg, and Hb, respectively, thereby obtaining the tristimulus values SCRr, SCRg, and SCRrb in the situation Sti. calculate.

  In the present embodiment, the brightness and chromaticity of W that can be expressed in each of the video display devices 100m and 100s in the situation Sti are equivalent to the brightness and chromaticity obtained from the target tristimulus value Ctw adjusted in the situation Stn. In order to achieve this, the following luminance condition A is satisfied.

  The luminance condition A is a condition that in each of the video display devices 100m and 100s, each Y representing the luminance in a state in which each of the R, G, and B images is displayed is equal to or greater than Ytr, Ytg, and Ytb of the target data Ct. It is. Specifically, the luminance condition A is a condition represented by the following formula (14).

  Expression (14) includes six expressions. Hereinafter, each expression included in Expression (14) is also referred to as a “brightness conditional expression”. Further, in the following, the luminance conditional expression related to the video display device 100m is also referred to as “luminance conditional expression m”. The luminance conditional expression m is an expression relating to each of Yrmi, Ygmi, and Ybmi in Expression (14).

  Further, in the following, the luminance conditional expression related to the video display device 100s is also referred to as “luminance conditional expression s”. The luminance conditional expression s is an expression relating to each of Yrsi, Ygsi, and Yrsi in Expression (14).

  In step S121m, the control unit 11 refers to the tristimulus value data SCRmi and the target data Ct to determine whether or not all luminance conditional expressions m are satisfied. If YES in step S121m, the process proceeds to step S130mA described later. On the other hand, if NO at step S121m, the process proceeds to step S122m.

  As described above, in the premise Pr2, the light source control unit 14 controls the luminance of the emitted light of each light source 3 in each of the video display devices 100m and 100s so that Yi ≧ Yt is satisfied. Therefore, all the luminance conditional expressions m in Expression (14) are satisfied.

  Therefore, it determines with YES by step S121m, and a process transfers to step S130mA.

  If there is a luminance conditional expression m that is not satisfied, luminance increase processing m is performed in step S122m. In the brightness increase process m, the light source control unit 14 performs a process of increasing the brightness of the emitted light of the light source 3 corresponding to the brightness condition expression m that is not satisfied among the brightness condition expressions m. For example, the light source control unit 14 controls the light source 3 so that the luminance value of the emitted light from the light source 3 is 1.1 times the value.

  For example, it is assumed that Ygmi ≧ Ytg is not satisfied, that is, Ygmi <Ytg. In this case, the light source control unit 14 controls the light source 3g so that the luminance value of the emitted light from the light source 3g is 1.1 times the value. Step S110 mA is performed again after the luminance increasing process m.

  If all the luminance conditional expressions m are not satisfied, steps S110 mA, S120 mA, and S122 m are repeatedly performed until all the luminance conditional expressions m are satisfied. When all the luminance conditional expressions m are satisfied (YES in S121m), the display characteristic calculation unit 15 uses the above-described tristimulus value data SCRmi indicating the latest tristimulus values SCRr, SCRg, SCRrb in the situation Sti as the control unit 11 And stored in the memory 12.

  In the video correction process Is performed by the video display device 100s, first, the process of step S110sA is performed.

  In step S110sA, a DSTsi acquisition process is performed as in the DSTs acquisition process of the video correction process Ns. Thereby, the detection unit SN1 sequentially transmits the tristimulus values DSTr, DSTg, and DSTb, which are the tristimulus values DSTsi, to the display characteristic calculation unit 15.

  In step S120sA, an SCRsi calculation process is performed. In the SCRsi calculation process, the display characteristic calculation unit 15 multiplies the received tristimulus values DSTr, DSTg, and DSTb by coefficients Hr, Hg, and Hb, respectively, thereby obtaining the tristimulus values SCRr, SCRg, and SCRrb in the situation Sti. calculate.

  In step S121s, the control unit 11 refers to the tristimulus value data SCRsi and the target data Ct to determine whether or not all luminance conditional expressions s are satisfied. If YES in step S121s, the process proceeds to step S125sA described later. On the other hand, if NO at step S121s, the process proceeds to step S122s.

  As described above, in the premise Pr2, the light source control unit 14 controls the luminance of the emitted light of each light source 3 in each of the video display devices 100m and 100s so that Yi ≧ Yt is satisfied. Therefore, all the luminance conditional expressions s in Expression (14) are satisfied.

  Therefore, YES is determined in step S121s, and the process proceeds to step S125sA.

  If there is a luminance conditional expression s that is not satisfied, a luminance increase process s is performed in step S122s. Since the brightness increase process s is the same process as the brightness increase process m, detailed description thereof is omitted. After the brightness increasing process s, step S110sA is performed again.

  If all the luminance conditional expressions s are not satisfied, steps S110sA, S120sA, and S122s are repeated until all the luminance conditional expressions s are satisfied. When all the luminance conditional expressions s are satisfied (YES in S121s), the display characteristic calculation unit 15 uses the above-described tristimulus value data SCRsi indicating the latest tristimulus values SCRr, SCRg, SCRrb in the situation Sti as the control unit 11 And stored in the memory 12.

  In step S125sA, SCRsi transmission processing is performed. In the SCRsi transmission process, the control unit 11 transmits the latest tristimulus value data SCRsi to the video display device 100m via the communication cable 16. Accordingly, the control unit 11 of the video display device 100m receives the tristimulus value data SCRsi and stores the tristimulus value data SCRsi in the memory 12. Then, the video display device 100m performs Step S130mA.

  In step S130 mA, Cti calculation processing is performed. Although details will be described later in the Cti calculation process, the calculation unit 13 of the video display device 100m first calculates the common data Cnti of the following equation (15) based on the tristimulus value data SCRmi and the tristimulus value data SCRsi. To do.

  In the following, Xntri, Yntri, and Zntri in Expression (15) are also referred to as “tristimulus values Cntri”. In the following, Xntgi, Yntgi, and Zntgi in Expression (15) are also referred to as “tristimulus values Cntgi”. In the following, Xntbi, Yntbi, and Zntbi in Expression (15) are also referred to as “tristimulus values Cntbi”.

  In the Cti calculation process, the calculation unit 13 first identifies the common region triangle TRcm as in the Ct calculation process.

  Here, it is assumed that the color reproduction range by the emitted light of each light source 3 in the situation Sti included in the video display device 100m is, for example, the triangle TRm in FIG. Further, it is assumed that the color reproduction range by the emitted light of each light source 3 in the situation Sti included in the video display device 100m is, for example, the triangle TRs in FIG. In addition, the color range that can be expressed in common on the screen 10 of each video display device Dp (video display devices 100m and 100s) under the situation Sti is, for example, the common range shown in FIG. Assume a region triangle TRcm.

  In this case, in the Cti calculation process, the calculation unit 13 calculates the chromaticities CPrm, CPgm, CPbm using the tristimulus values SCRr, SCRg, SCRrb of the tristimulus value data SCRmi, and specifies the triangle TRm. Note that the method for identifying the triangle TRm is the same as the process described with reference to FIG.

  Further, the calculation unit 13 calculates chromaticity CPrs, CPgs, CPbs using the tristimulus values SCRr, SCRg, SCRrb of the tristimulus value data SCRsi by a method similar to the method for specifying the triangle TRm, and the triangle TRs. Is identified.

  Next, as described above, the calculation unit 13 calculates the chromaticity CPrcm, the chromaticity CPgcm (chromaticity CPgs), and the chromaticity CPbcm based on the triangle TRm and the triangle TRs according to the rules Ru1 and Ru2, and the common region. The triangle TRcm is specified.

  The specified common area triangle TRcm indicates a range of colors that can be expressed in common on the screen 10 of the video display device Dp by each video display device Dp (video display devices 100m and 100s) under the situation Sti. .

  Next, the calculation unit 13 calculates the luminance with the smallest value among the luminance of the tristimulus value SCRr and the luminance of the tristimulus value data SCRsi as the common luminance.

  Hereinafter, the common luminance of R in the situation Sti is also referred to as “common luminance Yntri” or “Yntri”. In the following, the G common luminance in the situation Sti is also referred to as “common luminance Yntgi” or “Yntgi”. In the following, the common luminance of B in the situation Sti is also referred to as “common luminance Yntbi” or “Yntbi”.

  Specifically, the calculating unit 13 calculates the lowest luminance among the Yrmi (luminance) of the tristimulus value SCRr and the Yrsi (luminance) of the tristimulus value data SCRs as the common luminance Yntri. For example, when Yrmi is smaller than Yrsi, the calculation unit 13 calculates the Yrmi as the common luminance Yntri.

  The calculation unit 13 calculates either Ygmi or Ygsi as the common luminance Yntgi by the same method as the common luminance Yntri. The common luminance Yntbi is calculated using Ybmi and Ybsi in the same manner as the common luminance Yntri.

  Next, the calculation unit 13 uses the calculated chromaticities (chromaticity CPrcm, CPgs (CPgcm), CPbcm) and the calculated common luminances Yntri, Yntgi, Yntbi in the common region triangle TRcm to perform tristimulus. Calculate the value.

  Specifically, the calculation unit 13 calculates the tristimulus value from the common luminance Yntri and the coordinates of the chromaticity CPrcm in the u′v ′ chromaticity diagram by a method similar to the method described above with reference to FIG. Xntri and Zntri of Cntri are calculated. Thereby, the tristimulus value Cntri (Xntri, Yntri, Zntri) is calculated.

  The calculation unit 13 calculates the above-described tristimulus values Cntgi (Xntgi, Yntgi, Zntgi) using the common luminance Yntgi and the chromaticity CPgs (CPgcm) by the same method as the tristimulus values Cntri. In addition, the calculation unit 13 calculates the above-described tristimulus value Cntbi (Xntbi, Yntbi, Zntbi) using the common luminance Yntbi and the chromaticity CPbcm by the same method as the tristimulus value Cntri.

  And the calculation part 13 calculates the common data Cnti of Formula (15) which shows tristimulus value Cntri, Cntgi, Cntbi.

  Hereinafter, the data for specifying the target luminance and the target chromaticity in the situation Sti is also referred to as “target data Cti”.

  In the following, in the situation Sti, the target tristimulus value on the screen 10 in a state where the aforementioned situation StLra is generated is also referred to as “tristimulus value Ctri”. In the following, in the situation Sti, the target tristimulus value on the screen 10 in a state where the situation StLga is generated is also referred to as “tristimulus value Ctgi”. In the following, in the situation Sti, the target tristimulus value on the screen 10 in a state where the situation StLga is generated is also referred to as “tristimulus value Ctbi”.

  The target data Cti is data indicating tristimulus values Ctri, Ctgi, Ctbi. That is, the target data Cti indicates tristimulus values corresponding to each of R, G, and B. Therefore, the target data Cti is represented by a 3 × 3 matrix indicating nine elements.

  If the correction coefficient is calculated using the common data Cnti as the target data by a method similar to the method using the equations (6) and (11) described above, the luminance difference and chromaticity between the screens are calculated. The correction coefficient for reducing the difference can be calculated. However, the target tristimulus value of W in the situation Sti is a value obtained by changing the target tristimulus value of W in the situation Stn.

  Therefore, in the situation Sti, the correction coefficient is calculated by a method different from the situation Stn described above. In the situation Sti, the common data Cnti is used to calculate target data Cti that takes into account the change in the target tristimulus value of W. Then, a correction coefficient is calculated using the target data Cti.

  Specifically, the calculation unit 13 calculates coefficients Ai, Bi, and Ci that take into account changes in the target tristimulus value of W. The coefficients Ai, Bi, and Ci are calculated using the common data Cnti, the target tristimulus value Ctw calculated in step S131m described above, and the following equation (16).

  Next, the calculation unit 13 calculates the target data Cti using the common data Cnti, the coefficients Ai, Bi, and Ci and the following equation (17). The target data Cti is calculated by the following equation (17).

  Xtri, Ytri, and Ztri in Expression (17) are tristimulus values Ctri. Xtgi, Ytgi, Ztgi are the tristimulus values Ctgi. Xtbi, Ytbi, Ztbi are the tristimulus values Ctbi.

  In the following, the target luminance that can be commonly expressed on the screen 10 of the video display device Dp by each video display device Dp constituting the multi-screen display device 1000 under the situation Sti is also referred to as “target luminance Yti”. Say. That is, each of Ytri, Ytgi, Ytbi of the calculated target data Cti is the target luminance Yti. That is, the target data Cti is data for specifying the target luminance Yti.

  In the following, the target chromaticity that can be commonly expressed on the screen 10 of the video display device Dp by the video display devices Dp constituting the multi-screen display device 1000 under the situation Sti is referred to as “target chromaticity cti”. "

  Hereinafter, the target chromaticity of R in the situation Sti is also referred to as “target chromaticity ctri”. In the following, the target chromaticity of G in the situation Sti is also referred to as “target chromaticity ctgi”. In the following, the target chromaticity of B in the situation Sti is also referred to as “target chromaticity ctbi”. Each of the target chromaticities ctri, ctgi, and ctbi is the target chromaticity cti.

  It should be noted that the target chromaticity ctri in the u'v 'chromaticity diagram can be obtained by a general conversion equation using Xtri, Ytri, and Ztri of the target data Cti. Further, the target chromaticity ctgi in the u′v ′ chromaticity diagram can be obtained from Xtgi, Ytgi, Ztgi of the target data Cti in the same manner as the target chromaticity ctri. Further, the target chromaticity ctbi in the u′v ′ chromaticity diagram can be obtained from Xtbi, Ytbi, and Ztbi of the target data Cti in the same manner as the target chromaticity ctri. That is, the target data Cti is also data for specifying the target chromaticity cti.

  The target data Cti is calculated using each off-light Ln of each video display device Dp in the situation Sti. That is, the calculation unit 13 calculates the target data Cti based on each off light Ln of each video display device Dp in the situation Sti.

  In step S140 mA, Cti transmission processing is performed. In the Cti transmission process, the control unit 11 transmits the calculated target data Cti to the video display device 100s via the communication cable 16. Accordingly, the control unit 11 of the video display device 100s receives the target data Cti.

  In the video display device 100s, the process of step S141sA is performed. In step S141sA, a Cti storage process is performed. In the Cit storing process, the control unit 11 stores the received target data Cti in the memory 12.

  Further, in the video display device 100m, the process of step S141mA is performed. In step S141 mA, a Ct storage process i is performed. In the Ct storage process i, the control unit 11 stores the target data Cti in the memory 12.

  In step S150 mA, CSCmi calculation processing is performed. Although details will be described later in the CSCmi calculation process, the control unit 11 calculates the correction coefficient CSCmi based on the target data Cti corresponding to the situation Sti. That is, the control unit 11 is a calculation unit that calculates the correction coefficient CSCmi.

  The correction coefficient CSCmi is a coefficient indicating the coefficients RRmi, RGmi, RBmi, GRmi, GGmi, GBmi, BRmi, BGmi, BBmi in a matrix of 3 rows and 3 columns. Although details will be described later, the correction coefficient CSCmi is calculated using the following equation (18).

  In Expression (18), SCRmi is the tristimulus value data SCRmi of Expression (12). Cti is the target data Cti of Expression (17).

  Hereinafter, the display target video in the situation Sti is also referred to as “display target video Imi”. The display target video Imi is a video to be displayed on the screen 10 of each video display device Dp under the situation Sti.

  Hereinafter, the corrected pixel data obtained by multiplying the pixel data indicated by the video data by the correction coefficient CSCmi is also referred to as “corrected pixel data”. In the following, video data indicating k correction pixel data is also referred to as “corrected video data”. Hereinafter, the video signal Vsg indicating the corrected video data is also referred to as a “corrected video signal Vsga”.

  In the situation Sti, a corrected display target image Imi is obtained by performing processing using k correction pixel data corresponding to the image data.

  The correction coefficient CSCmi indicates the intensity of each component of the tristimulus values SCRr, SCRg, and SCRb. The correction coefficient CSCmi is a coefficient for correcting the luminance and chromaticity of the original video indicated by each video data indicated by the video signal Vsg.

  The correction coefficient CSCmi is a coefficient for making the luminance of the display target video Imi the same or equivalent to the target luminance Yti and making the chromaticity of the display target video Imi the same or equivalent to the target chromaticity cti. That is, the correction coefficient CSCmi minimizes the absolute value of the difference between the luminance of the display target video Imn and the target luminance Yti in the situation Sti, and the difference between the chromaticity of the display target video Imi and the target chromaticity cti in the situation Sti. Is a coefficient for minimizing the absolute value of.

  RRmi, RGmi, RBmi, GRmi, GGmi, GBmi, BRmi, BGmi, and BBmi in Expression (18) are RRm, RGm, RBm, GRm, GGm, GBm, BRm, BGm, and BBm in the situation Sti, respectively.

  In the CSCmi calculation process in step S150 mA, specifically, the control unit 11 calculates an equation in which the tristimulus value data SCRmi and the target data Cti are substituted into the equation (18). Thereby, the control unit 11 calculates the correction coefficient CSCmi.

  In step S151m, the control unit 11 refers to the correction coefficient CSCmi to determine whether or not the color reproduction condition m is satisfied. The color reproduction condition m is all the conditions indicated by the following expressions (19), (20), and (21).

  In the following, the target tristimulus value of W (white) in the situation Sti is expressed as “target tristimulus value Ctwi (Xtwi, Ytwi, Ztwi)” or “target tristimulus value Ctwi”.

  If the color reproduction condition m is not satisfied, the following problems occur. The inconvenience is that the white tristimulus value is the target tristimulus value Ctwi in a state where white obtained by simply mixing the tristimulus values Ctr, Ctg, and Ctb of the video display device 100m in the situation Sti is displayed. (Xtwi, Ytwi, Ztwi).

  If YES in step S151m, the process proceeds to step S160mA described later. On the other hand, if NO at step S151m, the process proceeds to step S152m.

  In step S152m, a luminance increase process mA is performed. In the luminance increase process mA, the light source control unit 14 performs a process of increasing the luminance of the emitted light from each light source 3. The light source control unit 14 controls the light sources 3r, 3g, and 3b so that the luminance value of the emitted light from each of the light sources 3r, 3g, and 3b is, for example, 1.1 times the value. And step S110mA is performed again.

  When the color reproduction condition m is not satisfied, the above processes are repeatedly performed until it is determined as YES in Step S121m and YES is determined in Step S151m.

  Hereinafter, white that can be expressed by red light (video light Lr), green light (video light Lg), and blue light (video light Lg) in the situation Sti is also referred to as “white Wi”. Hereinafter, white that can be expressed by red light (video light Lr), green light (video light Lg), and blue light (video light Lg) in the situation Stn is also referred to as “white Wn”. The correction coefficient CSCmi is a coefficient for changing white Wi to white Wn. Specifically, the correction coefficient CSCmi is a coefficient for minimizing the absolute value of the difference between the white Wi and the white Wn.

  When it is determined YES in step S151m, the control unit 11 stores the latest correction coefficient CSCmi in the memory 12. Thereafter, the process of step S160 mA is performed.

  In step S160 mA, correction processing mA is performed. The correction process mA is a process in which “correction coefficient CSCm” is replaced with “correction coefficient CSCmi” in the above description of the correction process m, and therefore, detailed description thereof will not be repeated.

  That is, by the complementary correction processing mA, the control unit 11 corrects the luminance and chromaticity of the original video indicated by each of the video data Irv, Igv, and Ibv indicated by the video signal Vsg based on the correction coefficient CSCmi, thereby displaying the display. The brightness and chromaticity of the target video Imi are corrected.

  The video display device 100s performs step S150sA after step S141sA.

  In step S150sA, CSCsi calculation processing is performed. Since the CSCsi calculation process is the same as the CSCmi calculation process, detailed description thereof is omitted. A brief description is given below.

  In the CSCs calculation process, the control unit 11 calculates the correction coefficient CSCsi based on the target data Cti corresponding to the situation Sti. That is, the control unit 11 is a calculation unit that calculates the correction coefficient CSCsi.

  The correction coefficient CSCsi is a coefficient indicating the coefficients RRsi, RGsi, RBsi, GRsi, GGsi, GBsi, BRsi, BGsi, BBsi in a matrix of 3 rows and 3 columns. Although details will be described later, the correction coefficient CSCsi is calculated using the following equation (22).

  The coefficients RRsi, RGsi, RBsi, GRsi, GGsi, GBsi, BRsi, BGsi, BBsi have the same role as the coefficients RRmi, RGmi, RBmi, GRmi, GGmi, GBmi, BRmi, BGmi, and BBmi, respectively.

  In equation (22), SCRsi is the tristimulus value data SCRsi of equation (13). Cti is the target data Cti of Expression (17).

  In the CSCsi calculation process of step S150sA, specifically, the control unit 11 calculates an equation in which the tristimulus value data SCRsi and the target data Cti are substituted into the equation (22). Thereby, the control unit 11 calculates the correction coefficient CSCsi. The correction coefficient CSCsi has the same function and role as the correction coefficient CSCmi.

  In step S151s, the control unit 11 refers to the correction coefficient CSCsi to determine whether or not the color reproduction condition s is satisfied. The color reproduction conditions s are all conditions represented by the following formulas (23), (24), and (25).

  Even if the color reproduction condition s is not satisfied, the above-described problem occurs when the color reproduction condition m is not satisfied.

  If YES in step S151s, the process proceeds to step S160sA described later. On the other hand, if NO at step S151s, the process proceeds to step S152s.

  In step S152s, a luminance increase process sA is performed. Since the brightness increase process sA is the same process as the brightness increase process mA, detailed description thereof is omitted. Then, Step S110sA is performed again.

  When the color reproduction condition s is not satisfied, the above processes are repeatedly performed until it is determined as YES in Step S121s and YES is determined in Step S151s.

  The correction coefficient CSCsi is a coefficient for changing white Wi to white Wn, like the correction coefficient CSCmi. Specifically, the correction coefficient CSCsi minimizes the absolute value of the difference between white Wi and white Wn. It is a coefficient to do. That is, the correction coefficient CSCsi has the same function and role as the correction coefficient CSCmi.

  When it is determined YES in step S151s, the control unit 11 stores the latest correction coefficient CSCsi in the memory 12. Thereafter, the process of step S160sA is performed.

  In step S160sA, a correction process sA is performed. Since the correction process sA is a process in which “correction coefficient CSCm” is replaced with “correction coefficient CSCsi” in the description of the correction process m described above, detailed description will not be repeated. The image Ir, the image Ig, and the image Ib are sequentially displayed on the screen 10 by the correction process s. As a result, the video Ic is expressed on the screen 10.

  As described above, the video correction process Im (correction process mA) and the video correction process Is (correction process sA) are performed. Thereby, each of the video display devices 100m and 100s in the situation Sti minimizes the absolute value of the difference between the luminance of the display target video Imn and the target luminance Yti in the situation Sti based on the correction coefficient, and the display target video. A correction process (correction process mA or correction process sA) is performed to minimize the absolute value of the difference between the chromaticity of Imn and the target chromaticity cti in the situation Sti.

  That is, in each of the video display devices 100m and 100s in the situation Sti, the luminance of the display video Imn is the same or equivalent to the target luminance Yt, and the chromaticity of the display target video Imn is the same or equivalent to the target chromaticity ctni. Become. That is, in each of the video display devices 100m and 100s in the situation Sti, the luminance and chromaticity of the display target video Imn are close to the target luminance Yti and the target chromaticity cti, respectively.

  Further, in the above-described premise Pr2 that the value Vb is smaller than the value Va, when white is displayed on the screen 10 in each of the video display devices 100m and 100s in the situation Sti, the brightness and chromaticity of the white are in the situation Stn. Same or equivalent to white brightness and chromaticity. That is, the following equation (26) is established.

  As described above, in steps S122m, S152m, S122s, and S152s in the video correction process Im and the video correction process Is, a process of increasing the luminance of the emitted light from the light source 3 is performed. Actually, there is a limit to the amount of increase in luminance of the light emitted from the light source 3. For example, when the luminance of the emitted light is controlled by controlling the forward voltage of the light source 3, there is a limit to the amount of forward voltage that can be supplied.

  Therefore, if the luminance of the emitted light from the light source 3 continues to decrease until Yi ≧ Yt cannot be established, the color reproduction condition m or the color reproduction condition s is not changed even if steps S122m, S152m, S122s, and S152s are performed. There are cases where it is not satisfied. In this case, the execution of the video correction process Im and the video correction process Is is stopped.

  In the above case, for example, the video display device Dp including the light source 3 that does not satisfy the color reproduction condition m or the color reproduction condition s may not be set as the target of the luminance increase process.

  As described above, according to this embodiment, the brightness and chromaticity of W of the screen 10 of each of the video display devices 100m and 100s are kept substantially constant regardless of the length of the cumulative driving time of the light source 3. be able to. In addition, the brightness and chromaticity other than W on each screen 10 constituting the multi-screen 10A can be automatically adjusted so that the brightness and chromaticity other than W are substantially the same.

(Specific numerical examples)
Next, by using specific numerical values, how much effect can be obtained after using each of the display devices 100m and 100s for a long time will be described.

  First, it is assumed that steps S110m, S120m, S110s, and S120s in FIG. 5 are performed in the situation Stn. It is assumed that the tristimulus value data SCRm and the tristimulus value data SCRs thus calculated indicate values of the following formulas (27) and (28).

  Further, the target data Ct calculated by performing steps S125s and S130m using the data of the above equations (27) and (28) shows the value of the following equation (29).

  From the target data Ct in Expression (29), the luminance and chromaticity (u′v ′ coordinates) of R, G, B, and W in the situation Stn are calculated as follows.

  The luminance of R is 64.1, and the u'v 'coordinate of R is (0.498, 0.509). The luminance of G is 300.5, and the u′v ′ coordinate of G is (0.118, 0.567). The luminance of B is 10.5, and the u′v ′ coordinate of B is (0.189, 0.079). The luminance of W is 375.1, and the u′v ′ coordinate of W is (0.190, 0.476).

  By substituting Equation (27) and Equation (29) into Equation (6) by Step S150m, the following Equation (30) is obtained.

  Moreover, the following formula | equation (31) is obtained by substituting a formula (28) and a formula (29) to a formula (11) by step S150s.

  Each value of Expression (30) also satisfies the conditions of Expression (7) to Expression (9). Each value of Expression (31) also satisfies the expression in which “m” is replaced with “s” in each of Expression (7), Expression (8), and Expression (9).

  In step S160m, a corrected video signal Vsga is obtained by performing a process using the correction coefficient CSCm of Expression (30). Then, the control unit 11 transmits the corrected video signal Vsga to the image display device 7.

  In step S160s, the corrected video signal Vsga is obtained by performing processing using the correction coefficient CSCs of Expression (31). Then, the control unit 11 transmits the corrected video signal Vsga to the image display device 7.

  Thereby, substantially the same brightness | luminance and chromaticity can be obtained in each screen 10 which comprises 10 A of multiscreens. The luminance and chromaticity in each screen 10 are the target luminance Yt and the target chromaticity ctn specified by the target data Ct in Expression (29).

  Next, processing for adjusting changes in luminance and chromaticity of images displayed on the screens 10 of the display devices 100m and 100s in the situation Sti will be described using specific numerical values.

  Here, the following premise Pr3 is considered. In the premise Pr3, it is assumed that the cumulative drive time of each light source 3 included in each of the video display devices 100m and 100s in the situation Sti is 30000 hours as an example. When the cumulative driving time is 30000 hours, the maximum luminance value YMx of the emitted light from each light source 3 is very low. That is, the characteristics of each light source 3 are deteriorated. Moreover, the chromaticity of the emitted light of each light source 3 in the situation Sti also changes.

  Assume that steps S110 mA, S120 mA, S110 sA, and S120 sA are performed in the video correction processing Im and the video correction processing Is of FIG. Thereby, the tristimulus value data SCRm and the tristimulus value data SCRs indicate, for example, values of the following formulas (32) and (33).

  In the values of Expression (32) and Expression (33), not all the luminance conditional expressions m and all the luminance conditional expressions s in Expression (14) are satisfied. Therefore, the luminance increase process m in step S122m and the luminance increase process s in step S122s are performed. Then, suppose that step S110mA, S120mA, S110sA, and S120sA were performed. Thereby, the tristimulus value data SCRm and the tristimulus value data SCRs indicate, for example, values of the following formulas (34) and (35).

  All luminance conditional expressions m and all luminance conditional expressions s in Expression (14) are satisfied by the values of Expression (34) and Expression (35).

  Thereafter, in the Cti calculation process of step S130 mA, the calculation unit 13 first calculates the common data Cnti using the tristimulus value data SCRmi of the equation (34) and the tristimulus value data SCRsi of the equation (35). . The calculated common data Cnti is represented by the following equation (36).

  Next, coefficients Ai, Bi, and Ci are calculated from the common data Cnti in Expression (36), the target tristimulus value Ctw calculated in Step S131m, and Expression (16).

  Next, the target data Cti of the following equation (37) is calculated from the common data Cnti of the equation (36), the calculated coefficients Ai, Bi, Ci, and the equation (17).

  Next, the correction coefficient CSCmi of Expression (38) and the correction coefficient CSCsi of Expression (39) are calculated by the processing of Steps S150mA and S150sA.

  The correction coefficient CSCmi in Expression (38) satisfies the color reproduction condition m (Expression (19), Expression (20), and Expression (21)). The correction coefficient CSCsi in Expression (39) satisfies the color reproduction condition s (Expression (23), Expression (24), and Expression (25)).

  From the target data Cti in Expression (37), the luminance and chromaticity (u′v ′ coordinates) of R, G, B, and W in the situation Sti (premise Pr3) are calculated as follows.

  The luminance of R is 63.6, and u'v 'coordinates of R are (0.506, 0.508). The luminance of G is 297.2, and the u′v ′ coordinate of G is (0.117, 0.567). The brightness of B is 14.2 and the u′v ′ coordinate of B is (0.182, 0.102). The luminance of W is 375.0, and the u′v ′ coordinate of W is (0.190, 0.476).

  Each of the above values is compared with each of the aforementioned values calculated from the target data Ct in Expression (29). In this case, the brightness and chromaticity of W in the situation Sti (premise Pr3) are substantially the same as the brightness and chromaticity of W (u′v ′ coordinate) calculated from the target data Ct in Expression (29). In addition, regarding the luminance and chromaticity (u′v ′ coordinate) of R, G, B, the luminance and chromaticity (u′v) of R, G, B calculated from the target data Ct of Expression (29) Equivalent to 'coordinates'.

  In step S160 mA, the corrected video signal Vsga is obtained by performing the processing using the correction coefficient CSCmi of Expression (38). Then, the control unit 11 transmits the corrected video signal Vsga to the image display device 7.

  In step S160sA, the corrected video signal Vsga is obtained by performing processing using the correction coefficient CSCsi of Expression (39). Then, the control unit 11 transmits the corrected video signal Vsga to the image display device 7.

  Thereby, substantially the same brightness | luminance and chromaticity can be obtained in each screen 10 which comprises 10 A of multiscreens. Moreover, the brightness | luminance and chromaticity in each screen 10 are the target brightness | luminance Yti specified by the target data Cti of Formula (37), and the target chromaticity ctni, respectively.

  From the above, it can be seen that a uniform image can be displayed over a long period of time by performing the processing of the present embodiment.

  Note that the video correction processing Im and the video correction processing Is described above may be repeatedly performed every predetermined time. The predetermined time is, for example, 24 hours, 100 hours, 1000 hours, or the like. Thereby, the luminance and chromaticity of W displayed on each screen 10 constituting the multi-screen 10A are kept substantially constant. Further, the luminance and chromaticity between the screens 10 constituting the multi-screen 10A are kept substantially the same. Thereby, it is possible to always display a uniform image on each screen 10 constituting the multi-screen 10A.

  For example, it is assumed that processing for correcting only the chromaticity of W (hereinafter, also referred to as “comparison processing”) is performed by the related technique A in Japanese Patent Laid-Open No. 10-090645 under the above-described premise Pr3. . The comparison process is a process to be compared with the present embodiment. When the comparison process is performed, the luminance and chromaticity (u′v ′ coordinates) of R, G, B, and W in the video display device 100m are as follows.

  The luminance of R is 54.7, and u'v 'coordinates of R are (0.506, 0.508). The luminance of G is 244.4, and the u′v ′ coordinate of G is (0.110, 0.574). The luminance of B is 6.0, and the u′v ′ coordinate of B is (0.192, 0.056). The luminance of W is 305.1, and u'v 'coordinates of W are (0.190, 0.476).

  When the comparison process is performed, the luminance and chromaticity (u′v ′ coordinates) of R, G, B, and W in the video display device 100s are as follows.

  The luminance of R is 53.3, and the u′v ′ coordinate of R is (0.521, 0.507). The luminance of G is 253.7, and the u′v ′ coordinate of G is (0.117, 0.567). The luminance of B is 7.0, and the u′v ′ coordinate of B is (0.172, 0.065). The luminance of W is 314.0, and the u'v 'coordinate of W is (0.190, 0.476).

  With reference to the above values, the chromaticity of W is adjusted to be substantially constant. However, the brightness has decreased from the situation Stn. There is also a difference in brightness between the screens. In addition, for each color other than W, there are also luminance and chromaticity differences between the screens.

  In general, when the distance Δu′v ′ between two points in the u′v ′ chromaticity diagram is 0.01 or more, the color difference corresponding to the distance between the two points can be recognized by the human eye. . As a result of the comparison processing, Δu′v ′ = 0.015 for R, Δu′v ′ = 0.010 for G, and Δu′v ′ = 0.02 for B. Therefore, in the comparison process, a chromaticity difference that can be recognized by human eyes is generated.

  As described above, the present embodiment can confirm the effects of keeping the luminance and chromaticity of W substantially constant and automatically adjusting the luminance and chromaticity between the screens 10 to be substantially the same.

  As described above, according to the present embodiment, in each video display device Dp, the cumulative driving time of the light source 3 is equal to or longer than the reference time i for causing the characteristics of the light source 3 to change. A correction process, which is a process for correcting the luminance and chromaticity of the display target video Imi, which is a video to be displayed on the screen 10 of the video display device Dp under the situation Sti, is performed.

  Thereby, the multi-screen display device can correct the luminance and chromaticity of the video to be displayed on the screen 10 when the characteristics of the light source 3 are changed.

  Further, according to the present embodiment, when W (white) is displayed on each screen 10 constituting the multi-screen 10A, regardless of the length of the cumulative driving time of each light source 3, the brightness and chromaticity of the W are displayed. Can always be kept substantially constant without the need for human adjustment. In addition, the brightness and chromaticity can be automatically adjusted so that the brightness and chromaticity other than W are substantially the same on each screen 10 constituting the multi-screen 10A. Thereby, it is possible to maintain the video quality at the beginning of use of the multi-screen display device 1000 for a long time without losing the sense of unity of the video displayed on the multi-screen 10A.

  As described above, the brightness and chromaticity of W can be maintained to be substantially constant, and the brightness and chromaticity other than W between the screens constituting the multi-screen can be automatically adjusted. Therefore, the frequency of adjustment of luminance and chromaticity can be reduced, and the cost for maintenance of the multi-screen display device can be suppressed.

  Further, according to the present embodiment, the luminance and chromaticity of the screen 10 can be set even when any color is displayed on each screen 10 constituting the multi-screen 10A regardless of the length of the cumulative driving time of the light source 3. It can be kept substantially constant. Even when a color other than an arbitrary color is displayed on each screen 10 constituting the multi-screen 10A, the brightness and chromaticity of each screen 10 can always be automatically adjusted so as to be substantially the same. Therefore, the multi-screen display device 1000 can display a uniform image over a long period of time.

  Further, according to the present embodiment, the brightness of W displayed on the multi-screen 10A related to the length of the cumulative driving time of each light source 3 is the same as the brightness of W at the beginning of use of the multi-screen display device 1000. It can be kept approximately the same. In addition, the chromaticity of W related to the length of the cumulative driving time of each light source 3 can also be kept substantially the same as the initially adjusted chromaticity.

  Note that colors other than W (for example, R, G, B single colors, and mixed colors other than W) change compared to the initial stage of use, but the chromaticity of the color is kept substantially the same between the screens 10. Can be adjusted automatically. Accordingly, it is possible to provide a multi-screen display device that can maintain the video quality for a long time without losing the sense of unity of the video displayed on the multi-screen 10A.

  Moreover, according to this Embodiment, the light source 3 is LED. Therefore, increase / decrease in the luminance of the light emitted from the light source 3 can be easily controlled.

  The R, G, and B LEDs have different lifetimes, that is, the degree of decrease in the luminance of the emitted light for each color as the cumulative driving time increases due to differences in the structure of the light emitting unit, the constituent materials, and the like. Different. Furthermore, the lifetime of the LED is susceptible to the environment in which the LED is used, particularly the temperature environment around the LED. Therefore, the lifetime of the LED is shortened even when the use environment temperature rises.

  Further, when the LED is driven by the pulse width modulation method, the life of the LED is shortened even if the duty ratio, that is, the ratio of the lighting time to the blinking period is increased. As described above, the lifetimes of the LEDs used as the light source of the projection display apparatus are individually different.

  In the method of adjusting the W chromaticity of the multi-screen so that the chromaticity of the W of the multi-screen is always kept constant during the use of the projection display apparatus as in the related art A described above, the chromaticity of W is kept substantially constant. Be drunk. However, when a single color other than W, such as R, G, B, or a mixed color other than W is displayed, the chromaticity cannot be kept constant between the screens. Therefore, the difference in chromaticity between adjacent screens is conspicuous, and the sense of unity of the video on the entire multi-screen is impaired. Further, there is a problem that the luminance of W decreases with time.

  Therefore, the multi-screen display device 1000 of the present embodiment is configured as described above. Therefore, the multi-screen display device 1000 can solve the above problems.

(Function block diagram)
FIG. 8 is a block diagram showing a characteristic functional configuration of the multi-screen display device BL10. The multi-screen display device BL10 is a multi-screen display device 1000. That is, FIG. 8 is a block diagram showing main functions related to the present invention among the functions of the multi-screen display device BL10.

  Multi-screen display device BL10 includes a plurality of video display devices (not shown) that communicate with each other. The video display device corresponds to the video display device Dp. In addition, the multi-screen display device BL10 includes a multi-screen (not shown) composed of a plurality of screens respectively included in the plurality of video display devices.

  Each video display device includes at least one light source (not shown) that is driven by emitting light. A part of the emitted light, which is light emitted from the light source of each video display device, is used to display a video on the screen of the video display device.

  Each video display device is supplied with a video signal indicating the original video. By irradiating the screen of each video display device with video light in which a part of the emitted light is modulated based on the original video indicated by the video signal, the video is displayed on the screen.

  The multi-screen display device BL10 functionally includes a first calculation unit BL1 and a second calculation unit BL2. The first calculation unit BL1 has a function of calculating target data for specifying target luminance that is target luminance and target chromaticity that is target chromaticity.

  The first calculation unit BL1 expresses each video display device on the screen of the video display device under the first situation based on another part of the emitted light of each video display device in the first situation. Target data for specifying possible target brightness and target chromaticity is calculated. The first situation is a situation in which the cumulative driving time of the light source is a time longer than a reference time for causing a change in the characteristics of the light source. The first calculation unit BL1 corresponds to the calculation unit 13.

  Each video display device includes a second calculation unit BL2. The second calculation unit BL2 calculates a correction coefficient for correcting the luminance and chromaticity of the original video indicated by the video signal based on the target data corresponding to the first situation. The second calculation unit BL2 corresponds to the control unit 11.

  Each video display device displays on the screen of the video display device under the first situation by correcting the luminance and chromaticity of the original video indicated by the video signal based on a correction coefficient. A correction process that is a process for correcting the luminance and chromaticity of the display target video that is the video is performed.

(Other variations)
As described above, the multi-screen display device according to the present invention has been described based on the embodiment, but the present invention is not limited to the embodiment. The present invention also includes modifications made to the embodiments that would occur to those skilled in the art without departing from the spirit of the present invention. That is, the present invention can be freely combined with each other within the scope of the invention, and the embodiments can be appropriately modified and omitted.

  Each of the video display devices 100m and 100s according to the present invention may not include all the components shown in FIG. That is, each of the video display devices 100m and 100s may include only the minimum components that can realize the effects of the present invention.

  Moreover, each function of the calculation part 13 and the control part 11 which is a calculation part contained in the multiscreen display apparatus 1000 may be implement | achieved by the processing circuit. That is, the multi-screen display device 1000 includes a processing circuit. The processing circuit is configured such that each video display device in the screen of the video display device is based on another part of the emitted light of each video display device in the first situation. It is a circuit for calculating target data for specifying the target luminance and the target chromaticity that can be expressed. The first situation is a situation in which the cumulative driving time of the light source is a time longer than a reference time for causing a change in the characteristics of the light source.

  The processing circuit is also a circuit for calculating a correction coefficient for correcting the luminance and chromaticity of the original video indicated by the video signal based on the target data corresponding to the first situation.

  The processing circuit may be dedicated hardware. The processing circuit may be a processor that executes a program stored in the memory. The processor is, for example, a CPU (Central Processing Unit), a central processing unit, an arithmetic unit, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), or the like.

  Hereinafter, the configuration in which the processing circuit is dedicated hardware is also referred to as “configuration Cs1”. In the following, the configuration in which the processing circuit is a processor is also referred to as “configuration Cs2”. In the following, a configuration that realizes the functions of the calculation unit 13 and the control unit 11 that is the calculation unit by a combination of hardware and software is also referred to as “configuration Cs3”.

  In the configuration Cs1, the processing circuit is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Applicable. The functions of the calculation unit 13 and the control unit 11 may be realized by two processing circuits, respectively. Further, all the functions of the calculation unit 13 and the control unit 11 may be realized by one processing circuit.

  A configuration in which all or a part of each component included in the multi-screen display device 1000 is indicated by hardware is, for example, as follows. Hereinafter, the multi-screen display device in which all or some of the components included in the multi-screen display device 1000 are represented by hardware is also referred to as “multi-screen display device hd10”.

  FIG. 9 is a hardware configuration diagram of the multi-screen display device hd10. Referring to FIG. 9, multi-screen display device hd10 includes a processor hd1 and a memory hd2. The memory hd2 is, for example, a nonvolatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM, or an EEPROM. Further, for example, the memory hd2 is a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD, or the like.

  In the configuration Cs2, the processing circuit is the processor hd1. In the configuration Cs2, the functions of the calculation unit 13 and the control unit 11 are realized by software, firmware, or a combination of software and firmware. Software or firmware is described as a program and stored in the memory hd2.

  In the configuration Cs2, the processing circuit (processor hd1) reads out the program stored in the memory hd2 and executes the program, whereby the functions of the calculation unit 13 and the control unit 11 are realized. That is, the memory hd2 stores the following programs.

  The program is expressed on the screen of the video display device under the first situation based on another part of the emitted light of the video display device in the first situation. This is a program for causing a processing circuit (processor hd1) to execute a step of calculating target data for specifying the possible target luminance and target chromaticity.

  The program further includes a step of calculating a correction coefficient for correcting the luminance and chromaticity of the original video indicated by the video signal based on the target data corresponding to the first situation. It is also a program for causing the (processor hd1) to execute.

  The program also causes the computer to execute a procedure of processing performed by each of the calculation unit 13 and the control unit 11, a method of executing the processing, and the like.

  In the configuration Cs3, some functions of the calculation unit 13 and the control unit 11 are realized by dedicated hardware. In the configuration Cs3, other partial functions of the calculation unit 13 and the control unit 11 are realized by software or firmware.

  For example, the function of the calculation unit 13 is realized by the processing circuit reading and executing a program stored in the memory. Further, for example, the function of the control unit 11 is realized by a processing circuit as dedicated hardware.

  Like the configuration Cs1, the configuration Cs2, and the configuration Cs3 described above, the processing circuit can realize the functions described above by hardware, software, firmware, or a combination thereof.

  In addition, the present invention may be realized as a video correction method in which the operation of the characteristic components included in the multi-screen display device 1000 is a step. The present invention may also be realized as a program that causes a computer to execute each step included in such a video correction method. Further, the present invention may be realized as a computer-readable recording medium that stores such a program. The program may be distributed via a transmission medium such as the Internet.

  The video correction method according to the present invention corresponds to, for example, the video correction process Im and the video correction process Is shown in FIG. The video correction method according to the present invention corresponds to, for example, the video correction process Nm and the video correction process Ns in FIG.

  All the numerical values used in the above-mentioned embodiment are examples of numerical values for specifically explaining the present invention. That is, the present invention is not limited to the numerical values used in the above embodiments.

  In the present invention, the embodiments can be freely combined within the scope of the invention, and the embodiments can be appropriately modified and omitted.

  3, 3r, 3g, 3b Light source, 10, 10m, 10s screen, 11 control unit, 13 calculation unit, 14 light source control unit, 100m, 100s, Dp video display device, 1000, BL10 multi-screen display device, SN1 detection unit.

Claims (5)

A multi-screen display device including a plurality of video display devices having a screen and communicating with each other,
Including a multi-screen composed of a plurality of the screens respectively possessed by the plurality of video display devices,
Each of the video display devices
Comprising at least one light source driven by emitting light;
A part of the emitted light that is the light emitted from the light source of each video display device is used to display a video on the screen of the video display device,
Each video display device is supplied with a video signal indicating the original video,
By irradiating the screen of each video display device with video light in which a part of the emitted light is modulated based on the original video indicated by the video signal, the video is displayed on the screen,
The multi-screen display device
A first calculation unit having a function of calculating target data for specifying target luminance that is target luminance and target chromaticity that is target chromaticity;
The first calculation unit is configured to distinguish the emitted light of each video display device in a first situation in which the cumulative driving time of the light source is equal to or longer than a reference time for causing a change in the characteristics of the light source. Based on a part of the image data, the target data for specifying the target luminance and the target chromaticity that can be expressed on the screen of the video display device by the video display device under the first situation is calculated. ,
Each video display device further includes:
A second calculation unit for calculating a correction coefficient for correcting the luminance and chromaticity of the original video indicated by the video signal based on the target data corresponding to the first situation;
Each video display device displays on the screen of the video display device under the first situation by correcting the luminance and chromaticity of the original video indicated by the video signal based on the correction coefficient. A multi-screen display device that performs a correction process that is a process for correcting the luminance and chromaticity of a display target video that is the video to be performed. The correction coefficient minimizes the absolute value of the difference between the luminance of the display target video and the target luminance in the first situation, and the chromaticity of the display target video and the target chromaticity in the first situation Is a coefficient to minimize the absolute value of the difference between
Each video display device minimizes the absolute value of the difference between the luminance of the display target video and the target luminance based on the correction coefficient, and the chromaticity of the display target video and the target chromaticity The multi-screen display device according to claim 1, wherein the correction process that minimizes the absolute value of the difference is performed. The light source has a function of changing the luminance of the emitted light,
Each video display device further includes:
A light source control unit having a function of controlling the light source so that the luminance of the emitted light changes,
The emitted light emitted by the light source in a second situation where the cumulative driving time is 0 or more and is 1 / h (h is an integer of 2 or more) times the reference time. The maximum luminance value is the first value,
In the first situation, the maximum value of the luminance of the emitted light emitted from the light source is a second value smaller than the first value,
In the second situation, the light source control unit is configured so that the light source emits the emitted light having a luminance that is smaller than the first value and has a suppression value that is less than or equal to the second value. Control the light source,
When the luminance of the video displayed on the screen in the second situation is expressed as Yt and the luminance of the video displayed on the screen in the first situation is expressed as Yi, the light source control unit further includes ,
(A1) Yi ≧ Yt is satisfied, and
(A2) In the first situation, the light source emits the emitted light having a luminance equal to or lower than the second value and equal to or higher than the suppression value.
The multi-screen display device according to claim 1, wherein the light source is controlled. The multi-screen display device includes three light sources,
The three light sources are a first light source, a second light source, and a third light source, respectively.
The emitted light of the first light source is red light,
The emitted light of the second light source is green light,
The emitted light of the third light source is blue light,
The correction coefficient is white that can be expressed by the red light, the green light, and the blue light in the first situation, the accumulated drive time is 0 or more, and 1 / h of the reference time ( 4. The coefficient for obtaining white that can be expressed by the red light, the green light, and the blue light in the second situation, where h is an integer of 2 or more times. 2. A multi-screen display device according to item 1. The multi-screen display device according to any one of claims 1 to 4, wherein the light source is an LED (Light Emitting Diode).

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