JP2004140800A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve color reproducibility of images even in the case of colorimetry of an image signal being different from a chrominance coordinate of three primary colors in light in an image display device. <P>SOLUTION: The image display device comprises a red light source 1 for generating a red light driven from a red light source drive circuit 21, a green light source 2 for generating a green light driven from a green light source drive circuit 22, a blue light source 3 for generating a blue light driven from a blue light source drive circuit 23, a spatial light modulator 6 for performing a spatial modulation of the red light, and a spatial light modulator 7 for performing a spatial light modulation of the green light. The device further comprises a spatial light modulator 8 for performing a spatial light modulation of the blue light; an image synthesizing optical system 9 for synthesizing each spatial modulated light generated from each spatial light modulator; a selecting circuit 55 for selecting the order of video signals from among a red video signal, a green video signal, and a blue video signal each for modulating an inputted light in each light source drive circuit; and a control circuit 61 for controlling drive timing, drive current, and/or drive timing of each of the light source drive circuits, and for controlling selection timing of the selecting circuit. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an improvement in an image display device that displays a color image by spatially modulating red, green, and blue light or light obtained by adding white light to the light.

2. Description of the Related Art Conventionally, a method of displaying a color image by spatially modulating and combining red, green and blue lights has already been known.
FIG. 11 shows a configuration example of a conventional spatial modulation type video display device (for example, see Patent Document 1).
This conventional image display apparatus includes a red light source 111, a green light source 112, a blue light source 113, spatial light modulators 116, 117, 118, an image combining optical system 119, a red light source driving circuit 121, a green light source driving circuit 121, and a green light source. Light source driving circuit 122, blue light source driving circuit 123, red space light modulator driving circuit 131, green space light modulator driving circuit 132, blue space light modulator driving circuit 133, red image memory 151, green It is roughly composed of an image memory 152, a blue image memory 153, a video signal processing circuit 154, and a timing control circuit 161.

First, a configuration of an optical system in a conventional image display device will be described with reference to FIG.
The red spatial light modulator 116 spatially modulates the red light incident from the red light source 111 to emit red image light. The green spatial light modulator 117 spatially modulates green light incident from the green light source 112 and emits green image light. The blue spatial light modulator 118 spatially modulates blue light incident from the blue light source 113 and emits blue image light.
The image combining optical system 119 combines the incident red image light, green image light, and blue image light into an image, and emits combined image light. The emitted composite image light is projected onto a screen (not shown) via a projection optical system (not shown).

Next, a circuit configuration of a conventional video display device will be described with reference to FIG. The red light source driving circuit 121, the green light source driving circuit 122, and the blue light source driving circuit 123 drive the red light source 111, the green light source 112, and the blue light source 113, respectively.
The red spatial light modulator driving circuit 131, the green spatial light modulator driving circuit 132, and the blue spatial light modulator driving circuit 133 respectively generate spatial light according to the red video signal, the green video signal, and the blue video signal. The modulators 116, 117 and 118 are driven.
The timing control circuit 161 operates the video signal processing circuit 154 and the operation timing of the red space light modulator drive circuit 131, the green space light modulator drive circuit 132, and the blue space light modulator drive circuit 133 according to the input video signal 101. Control.

The video signal processing circuit 154 performs video signal processing such as synchronization detection, color space conversion, and degamma on the input video signal 101 to generate a red video signal, a green video signal, and a blue video signal. I do. The video signal processing circuit 154 stores the red video signal, the green video signal, and the blue video signal in the red image memory 151, the green image memory 152, and the blue image memory 153, respectively, and performs reading processing.

FIG. 12 shows the control timing of each unit in the conventional video display device.
The red light source 111, the green light source 112, and the blue light source 113 are constantly driven to emit light. The video signal for driving each of the spatial light modulators 116, 117 and 118 is updated every frame period. The red spatial light modulator 116 is driven by the red video signal, the green spatial light modulator 117 is driven by the green video signal, and the blue spatial light modulator 118 is driven. Is a blue video signal.

Next, a method of making an image brighter in a conventional video display device will be described.
2. Description of the Related Art Conventionally, in order to display a color image, each pixel constituting a screen is decomposed into sub-pixels of three primary colors of red (R), green (G), and blue (B). There is a method in which the brightness is controlled so that the image is visually recognized as a color image.
However, in terms of brightness, if the screen is not sufficiently bright for the viewing environment, it will be difficult to see.
Therefore, a method has been proposed in which white (W) is added as a color component and brightness is given to the entire image to obtain a more visible color image.

As an example of such a case, in the case of a direct-view image display device, for example, in a liquid crystal display device disclosed in Patent Document 2, as sub-pixels constituting each pixel of a liquid crystal panel, in addition to the three colors R, G, and B, A W sub-pixel is provided, output luminance data for W is calculated by a decoder from input data of R, G, and B, and this luminance data is used together with R, G, and B input data, and R, G, and B of the liquid crystal panel are used. By driving the G, B, and W sub-pixels at the same time, it is possible to perform screen display with appropriate luminance.

On the other hand, in the case of a projector that projects a color image on a screen, generally, a spatial light modulator whose transmittance or reflectivity is spatially controlled by an image signal is three (R, G, B). By sequentially irradiating the light of the colors, the image of each color projected on the screen through the spatial light modulator is mixed visually, and a color sequential display method is adopted in which the images are recognized as a color image.

The human eye has an integration effect of a time constant of several tens of milliseconds, but the cycle of updating the image composed of red image light, green image light, and blue image light emitted from the spatial light modulator, that is, the image Since the frame period of a signal is usually shorter than the integration time constant of the human eye, when images of different colors are projected sequentially while changing over time within the frame period, the human eye sees a color image. Will be recognized as.

Next, a description will be given of a conventional example of a spatial light modulation type image display device in the case of employing a color sequential method. FIG. 13 is a block diagram showing a configuration of an optical system in a conventional color sequential video display device (for example, see Patent Document 1).
The optical system of this conventional image display device is roughly composed of a light source unit 100 including a red light source 111, a green light source 112, a blue light source 113, a color combining optical system 115, and a spatial light modulator 130. ing.

First, the configuration of a conventional video display device will be described with reference to FIG.
The red light source 111 emits red light. The green light source 112 emits green light. The blue light source 113 emits blue light. The color combining optical system 115 combines the incident red light, green light, and blue light, and sequentially emits them to the same optical path. The spatial light modulator 130 sequentially modulates and emits the light emitted from the color combining optical system 115.

As the color combining optical system 115 for combining the colors of red light, green light and blue light from each light source, a dichroic prism, a polarization unifying unit, a dichroic mirror, a fly-eye lens, or the like is used. At this time, an optical integrator may be used in order to reduce unevenness of light applied to the spatial light modulator 130.

Here, as an example in which a dichroic prism is used as the color combining optical system 115, for example, there is one disclosed in Patent Document 6. Also, as an example using a dichroic mirror, there is one disclosed in Patent Document 7, for example. Examples of the use of a fly-eye lens include those disclosed in Patent Documents 8 and 9, for example. The polarization unifying means is disclosed in, for example, Patent Document 10. Further, as an example having a configuration for reducing light unevenness by using an optical integrator, there is one disclosed in Patent Document 1, for example.

In the image display device shown in FIG. 13, red light, green light, and blue light emitted from red light source 111, green light source 112, and blue light source 113, respectively, are combined in color combining optical system 115 and have the same optical path. Is emitted. The spatial light modulator 130 has its light transmittance spatially controlled by a spatial light modulator drive signal, and spatially modulates and sequentially emits light incident from the color combining optical system 115. The red image light, the green image light, and the blue image light emitted from the spatial light modulator 130 are sequentially projected on a screen (not shown) via a projection optical system (not shown) to form a color image.

Next, with reference to FIG. 14, the control operation of the light source of each color in the conventional image display device shown in FIG. 13 will be described.
The spatial light modulator 130 is supplied with a spatial light modulator drive signal. As shown in FIG. 14, as the spatial light modulator driving signal, a red video signal (R-video), a green video signal (G-video), and a blue video signal (B-video) are sequentially input. .

During a period in which the red image signal is input to the spatial light modulator 130, red light from the red light source 111 enters the color combining optical system 115, and the green image signal is input to the spatial light modulator 130. During the period, the green light from the green light source 112 enters the color combining optical system 115, and during the period when the blue image signal is input to the spatial light modulator 130, the blue light from the blue light source 113 enters the color combining optical system 115. And sequentially enters the spatial light modulator 130 via the color combining optical system 115, so that the spatial light modulator 130 sequentially emits red image light, green image light, and blue image light as image light. Then, the image is projected on the screen, and is recognized as a color image.

Also in a color sequential video display device, by adding white (W) as a color component and imparting brightness to the entire image, it is possible to obtain a color image that is easier to see, and it is possible to obtain a spatial light modulator. There has already been proposed an arrangement in which an irradiation period of W light is added to an irradiation sequence of R, G, and B color lights for irradiating the image to impart brightness to the entire image (for example, Patent Document 3). , Patent Document 4 and Patent Document 5).

In these prior arts, as a method of generating R, G, B, and W color lights irradiated on the spatial light modulator, for example, a rotary type color filter plate (color wheel) is used, and R, G, B R, G, and B light beams are emitted by the filter regions of the respective colors, and a W region is arranged between the filter regions of the R, G, and B colors to emit the W light, so that the R and G light beams are emitted. , B, and W color light, and R, G, and B color light respectively assigned by three types of optical devices (for example, liquid crystal color filters) of R, G, and B. Irradiation with W light is performed by an optical device that emits W light while emitting light for each period, or by providing a period for emitting W light by passing through each of the R, G, and B optical devices, R, G, B, W colors There are a of a type that allows irradiating.

JP-A-10-269802 JP 2002-149116 A JP-A-11-102170 JP 2001-184037 A JP-A-2002-82652 JP-A-2000-56410 JP-A-8-240779 JP-A-11-32278 JP 2001-343706 A JP-A-6-289387

As a video display device that has been widely used, there is a well-known CRT (Cathode Ray Tube) receiver. In a CRT receiver, a phosphor is excited by an electron beam emitted from an electron gun, and red, green, and blue light is emitted. At this time, the luminance of the phosphor screen is controlled so as to be substantially proportional to the current density of the electron beam, and the current density of the electron beam is controlled so as to be proportional to the gradation component of the video signal.

The three primary colors of the CRT receiver are the emission colors of the phosphors of the respective colors, and the colors are reproduced by additively mixing the emission colors at a ratio according to the video signal.
Regarding the color reproducibility of a CRT receiver, see, for example, ITU-R Rec. BT. The standard of colorimetry is defined by 1361, and when a video signal according to this standard is projected by a CRT receiver, a video of an expected color is reproduced.
However, in the case of a video display device in which the chromaticity coordinates of the three primary colors are different, the color of the video is different.

In an image display device that displays an image by spatially modulating light from red, green and blue light sources, a semiconductor light emitting element or the like is used as a light source. Is different from the case of the CRT, the chromaticity coordinates of the three primary colors are changed to the above-mentioned ITU-R Rec. BT. It is difficult to make the same as the standard such as 1361, and the color reproducibility is different from that of the CRT.
Conventionally, as a color adjustment method in such a case, a method of simply adjusting the balance of the brightness of the three primary color light sources so that the white point conforms to the standard has been adopted.
However, according to this method, the hue can be made the same for the white point, but the color reproducibility is hardly corrected for a color having a high stimulus purity, that is, a vivid color.
As described above, in the case of a conventional video display device using a semiconductor light emitting element, there is a problem that color reproducibility is not sufficient.

In a color sequential video display apparatus, in a method of providing an irradiation period of W color light separately from an irradiation period of R, G, B color light, a white image signal is separately provided during the irradiation period of W color light. It is necessary to control the spatial light modulator, which causes a problem of a complicated circuit and a high speed.

The present invention has been made in view of the above circumstances, and in a video display apparatus that spatially modulates light from a light source of three primary colors to display a video, the colorimetry that the video signal follows is defined by the three primary colors It is an object of the present invention to provide a video display device having good color reproducibility even when light sources having different degree coordinates are used.
It is another object of the present invention to provide a video display device capable of adjusting color reproducibility in accordance with colorimetry followed by a video signal.
The present invention also provides a color sequential video display device that sequentially switches and displays red image light, green image light, and blue image light in time, and adds W color light irradiation without significantly complicating the circuit. It is another object of the present invention to provide a video display device capable of enhancing the brightness of an image.

In order to solve the above problem, the invention according to claim 1 relates to an image display device, and comprises a red light source that emits red light, a green light source that emits green light, a blue light source that emits blue light, and an image for red. At least one spatial light modulator for spatially modulating light from the red light source, the green light source, and the blue light source in accordance with the signal, the green image signal, and the blue image signal; and controlling the spatial light modulator. It is characterized by comprising selection control means for selecting a combination of a video signal and light to be modulated, and light quantity control means for controlling a time average value of a light flux of light modulated by the spatial light modulation means.

According to a second aspect of the present invention, there is provided the image display device according to the first aspect, wherein the spatial light modulating means sets a time average value of a light flux of red light modulated according to a red image signal to Lrr and a green light value. The time average of the red light flux modulated according to the video signal is Lgr, and the time average of the red light flux modulated according to the blue video signal is Lbr, and the green light modulated according to the red video signal is Lbr. Lg, the time average of the green light flux modulated according to the green video signal is Lgg, and the time average of the green light flux modulated according to the blue video signal is Lbg, Lrb is the time average of the light flux of blue light modulated according to the video signal for red, Lgb is the time average of the light flux of blue light modulated according to the video signal for green, and blue is the light modulated according to the blue video signal. Lbb is the time average of the light flux, and the red light and green light When the chromaticity coordinates of the blue and blue light in the CIE (Commission Internationale de l'Eclairage) 1931 standard color system are (xr, yr), (xg, yg), and (xb, yb), respectively, the colorimetry that the video signal follows Chromaticity coordinates (xr0, yr0), (xg0, yg0), (xb0, yb0) of the red, green, and blue colors in the above standard color system, and the time average of the red, green, and blue light fluxes Xr0 = (xr * Lrr / yr + xg * Lrg / yg + xb * Lrb / yb) between the value and the chromaticity coordinates of the red light, green light and blue light according to the standard color system. ) / (Lrr / yr + Lrg / yg + Lrb / yb)
yr0 = (Lrr + Lrg + Lrb) / (Lrr / yr + Lrg / yg + Lrb / yb)
xg0 = (xr * Lgr / yr + xg * Lgg / yg + xb * Lgb / yb) / (Lgr / yr + Lgg / yg + Lgb / yb)
yg0 = (Lgr + Lgg + Lgb) / (Lgr / yr + Lgg / yg + Lgb / yb)
xb0 = (xr * Lbr / yr + xg * Lbg / yg + xb * Lbb / yb) / (Lbr / yr + Lbg / yg + Lbb / yb)
yb0 = (Lbr + Lbg + Lbb) / (Lbr / yr + Lbg / yg + Lbb / yb)
Is characterized in that the relationship is established.

According to a third aspect of the present invention, there is provided the video display device according to the second aspect, wherein in the video display device,
Lr = Lrr + Lrg + Lrb
Lg = Lgr + Lgg + Lgb
Lb = Lbr + Lbg + Lbb
Chromaticity coordinates (xr0, yr0), (xg0, yg0), (xb0, yb0) in the standard color system of red, green, and blue in the colorimetry that the video signal follows, and the colorimetry that the video signal follows Between the chromaticity coordinates (xw, yw) of the standard white color in the CIE1931 standard color system, xw = (xr0 * Lr / yr0 + xg0 * Lg / yg0 + xb0 * Lb / yb0) / (Lr / (yr0 + Lg / yg0 + Lb / yb0)
yw = (Lr + Lg + Lb) / (Lr / yr0 + Lg / yg0 + Lb / yb0)
Is characterized in that the relationship is established.

According to a fourth aspect of the present invention, in the image display device according to the first aspect, the spatial light modulating means sets the time average value of the light flux of the red light modulated according to the red image signal to Lrr, The time average of the red light flux modulated according to the video signal is Lgr, and the time average of the red light flux modulated according to the blue video signal is Lbr, and the green light modulated according to the red video signal is Lbr. Lg, the time average of the green light flux modulated according to the green video signal is Lgg, and the time average of the green light flux modulated according to the blue video signal is Lbg, Lrb is the time average of the light flux of blue light modulated according to the video signal for red, Lgb is the time average of the light flux of blue light modulated according to the video signal for green, and blue is the light modulated according to the blue video signal. Lbb is the time average of the light flux, and the red light and green light And chromaticity coordinates of blue light in CIE (Commission Internationale de l'Eclairage) 1931 standard color system are (xr, yr), (xg, yg), (xb, yb), respectively, and Lr, Lg, Lb , Xr1, yr1, xg1, yg1, xb1, yb1 by the following equations: Lr = Lrr + Lrg + Lrb
Lg = Lgr + Lgg + Lgb
Lb = Lbr + Lbg + Lbb
xr1 = (xr * Lrr / yr + xg * Lrg / yg + xb * Lrb / yb) / (Lrr / yr + Lrg / yg + Lrb / yb)
yr1 = (Lrr + Lrg + Lrb) / (Lrr / yr + Lrg / yg + Lrb / yb)
xg1 = (xr * Lgr / yr + xg * Lgg / yg + xb * Lgb / yb) / (Lgr / yr + Lgg / yg + Lgb / yb)
yg1 = (Lgr + Lgg + Lgb) / (Lgr / yr + Lgg / yg + Lgb / yb)
xb1 = (xr * Lbr / yr + xg * Lbg / yg + xb * Lbb / yb) / (Lbr / yr + Lbg / yg + Lbb / yb)
yb1 = (Lbr + Lbg + Lbb) / (Lbr / yr + Lbg / yg + Lbb / yb)
Xw = (xr1 * Lr / yr1 + xg1 * Lg / yg1 + between the chromaticity coordinates (xw, yw) of the standard color system in colorimetry followed by the video signal according to the above standard color system. xb1 * Lb / yb1) / (Lr / yr1 + Lg / yg1 + Lb / yb1)
yw = (Lr + Lg + Lb) / (Lr / yr1 + Lg / yg1 + Lb / yb1)
Is characterized in that the following relationship is satisfied.

The invention according to claim 5 relates to the video display device according to any one of claims 1 to 4, wherein the video display device modulates with a red video signal, a green video signal, and a blue video signal. The luminous flux of the red light is Prr, Pgr, and Pbr, respectively, and the luminous flux of the green light modulated by the red video signal, the green video signal, and the blue video signal is Prg, Pgg, and Pbg, respectively. When the luminous flux of the blue light modulated by the video signal and the blue video signal is Prb, Pgb, and Pbb, respectively,
Prr = Pgr = Pbr
Prg = Pgg = Pbg
Prb = Pgb = Pbb
The relationship is established.

According to a sixth aspect of the present invention, there is provided the video display device according to any one of the first to fifth aspects, wherein the video display device has a period in which all light sources of each color are turned off during one frame period. It is characterized by.

According to a seventh aspect of the present invention, there is provided an image display apparatus, comprising: an illuminating means for adjusting respective luminous fluxes of red light, green light and blue light, switching over time and sequentially emitting light, and illuminating the light from the illuminating means. A spatial light modulating means for spatially modulating the spatial light modulating means by driving the spatial light modulating means by the red image signal; When the luminous flux of green light to be irradiated at the time of driving is Pg, and the luminous flux of blue light to be irradiated at the time of driving the spatial light modulating means by the video signal for blue is Pb, at the time of driving the spatial light modulating means by the video signal for red, A green light having a light flux K * Pg (K is a coefficient (0 ≦ K ≦ 1), the same applies hereinafter) and a blue light having a light flux K * Pb are applied to the spatial light modulator together with the red light, and the green light signal The spatial light modulator At the time of driving, the spatial light modulating means is irradiated with the blue light of the light flux K * Pb and the red light of the light flux K * Pr together with the green light, and at the time of driving the spatial light modulating means by the blue image signal, the light flux is emitted together with the blue light. The illumination device is characterized in that the illumination device is controlled so as to irradiate the spatial light modulation device with red light of K * Pr and green light of light flux K * Pg.

According to an eighth aspect of the present invention, there is provided the video display device according to the seventh aspect, wherein the illumination means is configured to be capable of changing a value of the coefficient K.

According to a ninth aspect of the present invention, there is provided an image display apparatus, comprising: an illuminating unit that adjusts respective luminous fluxes of red light, green light, and blue light, switches over time, and sequentially emits the light; A spatial light modulating means for spatially modulating the spatial light modulating means by irradiating the spatial light modulating means with red light and white light at the time of driving the spatial light modulating means by a red image signal; Irradiating the spatial light modulating means with green light and white light when driving the spatial light modulating means, and irradiating the spatial light modulating means with blue light and white light when driving the spatial light modulating means using a blue video signal. The illumination device is configured to control the illumination means so as to perform the illumination.

According to a tenth aspect of the present invention, there is provided the image display device according to the ninth aspect, wherein the driving timing of the spatial light modulating means by the white light using the red video signal, the green video signal, and the blue video signal. Irradiates the spatial light modulation means in accordance with

The invention according to claim 11 relates to the video display device according to claim 9, characterized in that the white light is always turned on.

According to a twelfth aspect of the present invention, there is provided the video display device according to any one of the ninth to eleventh aspects, wherein the brightness of the white light can be changed by external control. .

According to a thirteenth aspect of the present invention, there is provided the video display device according to any one of the first to twelfth aspects, wherein the light source of the red light, the green light, the blue light, or the white light is an LED (Light Emitting Diode). It is characterized by:

The invention according to claim 14 relates to the video display device according to claim 13, wherein the LED comprises a plurality of LEDs.

According to the image display device of the present invention, the means for controlling the time average value of the luminous flux is provided, and spatial light modulation is performed for each light source of each color by a combination of red, green, and blue video signals. Regardless of the chromaticity coordinates, the chromaticity coordinates of the substantially three primary colors and white can be changed, and therefore, it is possible to realize desired color reproducibility.
In addition, a means for controlling the time average value of the light beam is provided, and spatial light modulation is performed by a combination of red, green, and blue video signals for each light source of each color, and the time average value of the light beam is accurately adjusted. Therefore, even when using a light source having different chromaticity coordinates of the three primary colors from the colorimetry followed by the video signal, the color reproducibility of the substantial three primary colors or the color reproducibility of the substantial three primary colors and white is improved. Can be.
Further, a means for controlling the time average value of the light beam is provided, so that spatial light modulation is performed by a combination of red, green, and blue video signals for each light source of each color, and the time average value of the light beam is accurately adjusted. Thus, even when the chromaticity coordinates of the substantial three primary colors are changed, the color reproducibility of white can be improved.

Further, according to the image display device of the present invention, the illumination unit capable of adjusting the respective luminous fluxes of the red light, the green light and the blue light, and the spatial light modulation unit for modulating the light from the illumination unit are provided. When controlling the spatial light modulator according to the video signal, the spatial light modulator is irradiated not only with red light but also with green light and blue light, and similarly, according to the green video signal, the spatial light modulation is performed. When controlling the spatial light modulator, the spatial light modulator irradiates not only green light but also blue light and red light, and according to the video signal for blue, the spatial light modulator Since not only blue light but also red light and green light are radiated, the brightness of the image can be enhanced. Also, at this time, since the lighting means has a function of adjusting the brightness, the degree of brightness can be adjusted according to the contents of the image source and the viewing environment.

Further, according to the image display device of the present invention, there are provided illumination means capable of adjusting the respective luminous fluxes of red light, green light, blue light and white light, and spatial light modulation means for modulating light from the illumination means. When controlling the spatial light modulator according to the video signal for red, the spatial light modulator is irradiated not only with red light but also with white light, and similarly, the spatial light modulator is controlled according to the video signal for green. When the spatial light modulator irradiates not only green light but also white light to the spatial light modulator and controls the spatial light modulator according to the blue video signal, the spatial light modulator emits not only blue light but also white light. Since the illumination is performed, the brightness of the image can be enhanced.

The image display device is operated according to a red light source that emits red light, a green light source that emits green light, a blue light source that emits blue light, and a red video signal, a green video signal, and a blue video signal. At least one spatial light modulator for spatially modulating light from the red light source, the green light source, and the blue light source; and a selection controller for selecting a combination of a video signal for controlling the spatial light modulator and light to be modulated. And a light quantity control means for controlling a time average value of the light flux of the light modulated by the spatial light modulation means.
Further, in the image display device, an illuminating means for adjusting the respective luminous fluxes of the red light, the green light and the blue light, switching over time, and sequentially emitting the light, and a spatial light modulator for spatially modulating the light from the illuminating means. Means, and the luminous flux of red light radiated at the time of driving the spatial light modulating means by the red image signal is Pr, the luminous flux of green light radiated at the time of driving the spatial light modulating means by the green image signal is Pg, When the luminous flux of the blue light irradiated at the time of driving the spatial light modulating means by the blue image signal is Pb, when driving the spatial light modulating means by the red image signal, the luminous flux K * Pg (K is a coefficient ( 0 ≦ K ≦ 1), the same applies hereinafter) to the spatial light modulating means by irradiating the spatial light modulating means with the green light of luminous flux K * Pb and luminous flux together with the green light when the spatial light modulating means is driven by the green image signal. K * Pb Irradiating the spatial light modulating means with the blue light and the red light of the light flux K * Pr, and driving the spatial light modulating means with the blue video signal, together with the blue light, the red light and the light flux K * of the light flux K * Pr. The illumination means is controlled so as to irradiate the spatial light modulation means with Pg green light.
Further, in the image display device, an illuminating means for adjusting the respective luminous fluxes of the red light, the green light and the blue light, switching over time, and sequentially emitting the light, and a spatial light modulator for spatially modulating the light from the illuminating means. Means for irradiating the spatial light modulating means with red light and white light at the time of driving the spatial light modulating means by the red image signal, and emitting green light and white light at the time of driving the spatial light modulating means by the green image signal. And irradiating the spatial light modulating means with light and controlling the illuminating means to irradiate the spatial light modulating means with blue light and white light when the spatial light modulating means is driven by the blue video signal. I do.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The description will be made specifically using an embodiment.

FIG. 1 is a block diagram showing a configuration of a video display device according to a first embodiment of the present invention, FIG. 2 is a timing chart showing a control method of a light source of each color in the video display device of the present embodiment, and FIG. 6 is a timing chart showing another control method of the light source of each color in the video display device of the embodiment.

As shown in FIG. 1, the image display device of this example includes a red light source 1, a green light source 2, a blue light source 3, a red spatial light modulator 6, a green spatial light modulator 7, A blue spatial light modulator 8, an image combining optical system 9, a red light source drive circuit 21, a green light source drive circuit 22, a blue light source drive circuit 23, a red space light modulator drive circuit 31, a green space Light modulator drive circuit 32, blue space light modulator drive circuit 33, red image memory 51, green image memory 52, blue image memory 53, video signal processing circuit 54, and 3-3 selection circuit (RGB) And a timing control circuit 61.

First, the configuration of the optical system in the video display device of this example will be described.
The red light source 1, the green light source 2, and the blue light source 3 generate monochromatic light of red, green, and blue, respectively. As the red light source 1, the green light source 2 and the blue light source 3, it is preferable to use LEDs (Light Emitting Diodes) of respective colors, thereby generating red, green and blue monochromatic light and applying an applied current. The luminous flux can be controlled by the value. Furthermore, since the response time is several microseconds or less and is sufficiently short with respect to the frame period of the image to be displayed, it is possible to control the light source as described later. When LEDs are used as the light source of the video display device, the quantity of light per LED is not sufficient, so it is desirable to use a plurality of LEDs for each color.

The spatial light modulators 6, 7, and 8 change the light transmittance of each part of a space of a fixed size according to an image, and are a TN (Twisted Nematic) type liquid crystal panel, a ferroelectric liquid crystal panel, or A DMD (Digital Micro-mirror Device) or the like is used.
The TN liquid crystal panel utilizes the properties of a light-transmitting substance, such as optical rotation and birefringence, and changes the magnitude of light passing therethrough by controlling the degree of polarization according to an applied voltage value.

A ferroelectric liquid crystal panel uses birefringence, and switches between two polarization states according to the polarity of an applied voltage. The brightness of transmitted light is controlled by PWM (Pulse Width Modulation). You.

The TN liquid crystal panel and the ferroelectric liquid crystal panel include a transmission type and a reflection type .
In the case of a spatial light modulator using a transmission type liquid crystal panel, polarizers are provided on the light incident side and the light emission side of the liquid crystal panel, respectively. In the case of a spatial light modulator using a reflective liquid crystal panel, a PBS (Polarizing Beam Splitter) is provided on the side of the liquid crystal panel where light enters and exits.
DMD is a reflection type spatial light modulator. The DMD has micromirrors for the number of pixels, and switches the tilt of the micromirrors according to the polarity of the applied voltage. The tilt of the controlled micromirror is in two states (ON state and OFF state), and the brightness of the passing light is controlled by PWM (Pulse Width Modulation). In other words, the longer the ON state and the shorter the OFF state, the brighter. Therefore, the brightness is controlled by controlling the time distribution between the ON state and the OFF state. A TIR prism (total reflection prism) may be used in some cases in order to reduce the decrease in contrast due to the OFF state of the reflected light leaking into the projection optical system.

The image combining optical system 9 includes a cross dichroic prism, a dichroic mirror, and the like, and combines the red image light, the green image light, and the blue image light to generate a combined image light. When a DMD is used as the spatial light modulator, a color separation / color combination prism and a TIR prism may be used.

Next, the operation of the video display device having the above configuration will be described.
The red light source drive circuit 21, the green light source drive circuit 22, and the blue light source drive circuit 23 drive the red light source 1, the green light source 2, and the blue light source 3, respectively, to control the lighting state. The red space light modulator drive circuit 31, the green space light modulator drive circuit 32, and the blue space light modulator drive circuit 33 are respectively a red image signal and a green image signal from the 3-3 selection circuit (RGB simultaneous selection circuit) 55. The spatial light modulator 6 for red, the spatial light modulator 7 for green, and the spatial light modulator 8 for blue are driven in accordance with the video signal and the blue video signal, respectively, to transmit light in each space. Change the rate (or reflectivity).

The timing control circuit 61 includes a red light source driving circuit 21, a green light source driving circuit 22, and a blue light source driving circuit 23, a red spatial light modulator driving circuit 31, and a green spatial light modulator driving circuit 32 according to the input video signal 101. In addition to controlling the operation timings of the blue light modulator driving circuit 33, the video signal processing circuit 54, and the 3-3 selection circuit (RGB simultaneous selection circuit) 55, the red light source driving circuit 21, the green light source driving circuit 22, The control of the magnitude of the driving power from the blue light source driving circuit 23 to the red light source 1, the green light source 2 and the blue light source 3 or the control of the supply time of the driving power, or the light source of each color is constituted by a plurality of light emitting elements, respectively. If so, control is performed to switch the number of light-emitting elements of each color. Note that control of the magnitude of the driving power, control of the supply time of the driving power, and switching of the number of light emitting elements may be used together.
Further, the timing control circuit 61 may be configured to be able to determine the standard that the input video signal 101 follows, and to switch the control according to the colorimetry in the standard.

The red image memory 51, the green image memory 52, and the blue image memory 53 temporarily store a red image signal, a green image signal, and a blue image signal, respectively.
The video signal processing circuit 54 performs video signal processing such as synchronization detection, color space conversion, and degamma according to the video signal input 101 to generate a red video signal, a green video signal, and a blue video signal. The data stored in the red image memory 51, the green image memory 52, and the blue image memory 53, respectively, and the output of the data read from the red image memory 51, the green image memory 52, and the blue image memory 53 to the 3-3 selection circuit 55 are stored. Control.

The 3-3 selection circuit 55 responds to the timing control of the timing control circuit 61 to output the red video signal, the green video signal, and the blue video input from the red image memory 51, the green image memory 52, and the blue image memory 53. The signals are selected from the signals and output to the red space light modulator drive circuit 31, the green space light modulator drive circuit 32, and the blue space light modulator drive circuit 33, respectively.

Hereinafter, the control and operation of the video display device of this example will be described with reference to FIGS.
The red spatial light modulator 6 spatially modulates the red light incident from the red light source 1 and emits red image light, and the green spatial light modulator 7 emits green light incident from the green light source 2. The green image light emitted by spatial light modulation and the blue image light emitted by the blue spatial light modulator 6 after spatially modulating the blue light incident from the blue light source 3 are output to the image combining optical system 9. Incident.
The image synthesizing optical system 9 synthesizes images of the red image light, the green image light, and the blue image light, and emits synthesized image light.
The combined image light is projected onto a screen (not shown) by a projection optical system (not shown).

In the first control method in the video display device of this example, as shown in FIG. 2, the order of video signals for driving the red spatial light modulator 6 during one frame period is changed to red, The order of video signals for driving the green spatial light modulator 7 is green, blue, and red. The order of video signals for driving the blue spatial light modulator 8 is blue. , Red and green.

However, the order of the colors of the video signals input to the spatial light modulators 6, 7 and 8 is not limited to the above example. The order may be all red, green, and blue.
In this case, there is an advantage that only one type of video signal is output from the 3-3 selection circuit 55. However, on the other hand, the distribution of the color of the synthesized image light on the time axis is biased, and a phenomenon called so-called color breakup occurs. Is more likely to appear. However, according to the example shown in FIG. 2, the color breakup is hardly noticeable.

Here, one frame period is defined as Tf, and in the red spatial light modulator 6, a red image signal (R-video), a green image signal (G-video), and a blue image signal (B) per one frame period Tf. -video), the time for modulating the red light is Trr, Tgr, Tbr, and the light flux of the red light to be modulated is Prr, Pgr, Pbr, respectively.
Similarly, in the green spatial light modulator 7, the time for modulating the green light by the video signal for red, the video signal for green, and the video signal for blue per frame period Tf is Trg, Tgg, and Tbg, respectively. Let the luminous flux of the green light be Prg, Pgg, Pbg, respectively.
Further, in the blue spatial light modulator 8, the time for modulating the blue light by the red image signal, the green image signal, and the blue image signal per frame period Tf is Trb, Tgb, Tbb, respectively. Let the light flux be Prb, Pgb, Pbb, respectively.

Now, Lrr, Lrg, Lrb, Lgr, Lgg, Lgb, Lbr, Lbg, Lbb are defined as follows.
Lrr = Prr * Trr / Tf
Lrg = Prg * Trg / Tf
Lrb = Prb * Trb / Tf
Lgr = Pgr * Tgr / Tf
Lgg = Pgg * Tgg / Tf
Lgb = Pgb * Tgb / Tf
Lbr = Pbr * Tbr / Tf
Lbg = Pbg * Tbg / Tf
Lbb = Pbb * Tbb / Tf
… (1)

In this case, Lrr, Lrg, Lrb, Lgr, Lgg, Lgb, Lbr, Lbg, and Lbb represent the following quantities, respectively.
Lrr: time average value of the luminous flux of red light modulated in accordance with the red image signal in the red spatial light modulator 6
Lgr: Time average value of the luminous flux of red light modulated according to the green image signal in the red spatial light modulator 6
Lbr: Time average value of the luminous flux of red light modulated in accordance with the blue video signal in the red spatial light modulator 6

Lrg: time average value of the green light flux modulated in accordance with the red video signal in the green spatial light modulator 7
Lgg: a time average value of the green light flux modulated in accordance with the green image signal in the green spatial light modulator 7
Lbg: a time average value of the luminous flux of green light modulated according to the blue video signal in the green spatial light modulator 7

Lrb: time average value of the luminous flux of blue light modulated in accordance with the red image signal in the blue spatial light modulator 8
Lgb: Time average value of the luminous flux of blue light modulated in accordance with the green image signal in the blue spatial light modulator 8
Lbb: Time average value of the luminous flux of blue light modulated in accordance with the blue video signal in the blue spatial light modulator 8

Lr, Lg, and Lb are defined as follows.
Lr = Lrr + Lrg + Lrb
Lg = Lgr + Lgg + Lgb
Lb = Lbr + Lbg + Lbb
… (2)

In this case, Lr, Lg, and Lb represent the following quantities, respectively.
Lr: time average value of the luminous flux of red light, green light and blue light modulated in accordance with the red image signal in the red spatial light modulator 6, the green spatial light modulator 7 and the blue spatial light modulator 8 Sum of
Lg: Time average value of the luminous flux of red light, green light and blue light modulated in accordance with the green image signal in the red spatial light modulator 6, the green spatial light modulator 7 and the blue spatial light modulator 8 Sum of
Lb: Time average value of the luminous flux of red light, green light and blue light modulated according to the blue video signal in the red spatial light modulator 6, the green spatial light modulator 7 and the blue spatial light modulator 8 Sum of

Since the human eye has an effect of integrating light, a product obtained by multiplying the light flux of the light source by the light emission time represents the substantial brightness of the light source. That is, Lrr, Lrg, Lrb, Lgr, Lgg, Lgb, Lbr, Lbg, Lbb, Lr, Lg, and Lb represented by Expressions (1) and (2) are the actual brightness per one frame period Tf. Is represented.
The adjustment of the substantial brightness of the light source may be controlled by the power applied to the light source, or may be controlled by the time during which the power is applied to the light source.
When each light source is composed of a plurality of light emitting elements, the actual brightness of the light source may be adjusted by switching the number of light emitting elements.

Further, as a method of expressing colors, generally, chromaticity coordinates according to the CIE (Commission Internationale de l'Eclairage) 1931 standard color system (so-called XYZ color system) are used.
The chromaticity coordinates of the red light source, the green light source, and the blue light source in the XYZ color system in the video display device of the present invention are (xr, yr), (xg, yg), and (xb, yb), respectively, and are newly generated. Assuming that the chromaticity coordinates of the three primary colors are (xr0, yr0), (xg0, yg0), and (xb0, yb0), from the relationship between the chromaticity coordinates in the XYZ color system and the brightness related to the light measurement, Become.

xr0 = (xr * Lrr / yr + xg * Lrg / yg + xb * Lrb / yb) / (Lrr / yr + Lrg / yg + Lrb / yb)
yr0 = (yr * Lrr / yr + yg * Lrg / yg + yb * Lrb / yb) / (Lrr / yr + Lrg / yg + Lrb / yb)
= (Lrr + Lrg + Lrb) / (Lrr / yr + Lrg / yg + Lrb / yb)
xg0 = (xr * Lgr / yr + xg * Lgg / yg + xb * Lgb / yb) / (Lgr / yr + Lgg / yg + Lgb / yb)
yg0 = (yr * Lgr / yr + yg * Lgg / yg + yb * Lgb / yb) / (Lgr / yr + Lgg / yg + Lgb / yb)
= (Lgr + Lgg + Lgb) / (Lgr / yr + Lgg / yg + Lgb / yb)
xb0 = (xr * Lbr / yr + xg * Lbg / yg + xb * Lbb / yb) / (Lbr / yr + Lbg / yg + Lbb / yb)
yb0 = (yr * Lbr / yr + yg * Lbg / yg + yb * Lbb / yb) / (Lbr / yr + Lbg / yg + Lbb / yb)
= (Lbr + Lbg + Lbb) / (Lbr / yr + Lbg / yg + Lbb / yb)
… (3)

Coordinates (xr, yr), coordinates (xg, yg), coordinates (xb, yb), ratio (Lrr: Lrg: Lrb), ratio (Lgr: Lgg: Lgb), ratio (Lbr: Lbg: Lbb) Once determined, the coordinates (xr0, yr0), coordinates (xg0, yg0), and coordinates (xb0, yb0) are determined.
That is, when a light source whose chromaticity coordinates in the XYZ color system are (xr, yr), (xg, yg), (xb, yb) is used, the substantial brightness ratio (Lrr: Lrg: By adjusting (Lrb), (Lgr: Lgg: Lgb), and (Lbr: Lbg: Lbb), it is possible to generate three primary colors whose chromaticity coordinates are equal to the three primary colors in the colorimetric standard followed by the video signal. Of course, three primary colors of desired chromaticity coordinates can be generated.

If the chromaticity coordinates of the white point are (xw, yw), the following relationship is derived from the above.
xw = (xr0 * Lr / yr0 + xg0 * Lg / yg0 + xb0 * Lb / yb0) / (Lr / yr0 + Lg / yg0 + Lb / yb0)
yw = (yr0 * Lr / yr0 + yg0 * Lg / yg0 + yb0 * Lb / yb0) / (Lr / yr0 + Lg / yg0 + Lb / yb0)
= (Lr + Lg + Lb) / (Lr / yr0 + Lg / yg0 + Lb / yb0)
… (4)

Therefore, when using the three primary colors whose chromaticity coordinates are (xr0, yr0), (xg0, yg0), (xb0, yb0), adjust the substantial brightness ratio (Lr: Lg: Lb) of the light source. As a result, it is possible to generate a white color having the same chromaticity coordinates as the standard white in the colorimetric standard followed by the video signal. Of course, it is also possible to generate white with desired chromaticity coordinates.
As described above, in the video display device of this example, the three primary colors and the standard white in the colorimetric standard followed by the input video signal and the three primary colors and the white having the same chromaticity coordinates can be generated. It becomes possible to reproduce.

Hereinafter, a specific calculation example will be described. Suppose now that the input video signal conforms to the ITU-R Rec.BT.1361 standard.
Considering the coefficient of the luminance equation in ITU-R Rec.BT.1361,
Lr / 0.2126 = Lg / 0.7152 = Lb / 0.722… (5)
And it is sufficient.
The chromaticity coordinates of the three primary colors in ITU-R Rec.BT.1361 are as follows.
(xr0, yr0) = (0.640, 0.330)
(xg0, yg0) = (0.300,0.600)
(xb0, yb0) = (0.150,0.060)
… (6)

Now, it is assumed that the chromaticity coordinates of the red light source, the green light source, and the blue light source are as follows, for example.
(xr, yr) = (0.690, 0.300)
(xg, yg) = (0.290, 0.680)
(xb, yb) = (0.150,0.060)
… (7)
From this, the following relational expression is obtained by substituting Expressions (5), (6), and (7) into Expression (3).
Lrr / 0.1707 = Lrg / 0.0410 = Lrb / 0.0009 = Lgr / 0.0207
= Lgg / 0.6878 = Lgb / 0.0067 = Lbb / 0.0722
Lbr = Lbg = 0.0000
… (8)

FIG. 3 shows a second control method in the video display device of this example.
In the calculation example shown in Expression (8), Lbr, Lbg, and Lrb hardly contribute to the color reproducibility. Therefore, as shown in FIG. 3, the processing may be reduced by setting Tbr = Tbg = Trb = 0. As a result, the time for allocating Lrr, Lgg, and Lbb, which are the main components, can be increased, so that an effect that the brightness can be further increased is produced.

Further, in the example of FIG. 2, Trr = Tgr = Tbr = Trg = Tgg = Tbg = Trb = Tgb = Tbb, but as is known from equation (1), Prr * Trr, Prg * Trg, Prb * Trb, Pgr * Tgr, Pgg * Tgg, Pgb * Tgb, Pbr * Tbr, Pbg * Tbg, Pbb * Tbb, as long as each is constant, for example, Prr = Pgr = Pbr, Prg = Pgg = Pbg, Prb = Pgb = Pbb may be set so that the applied power is constant for each light source.
By doing so, the applied power becomes constant for each light source, so that it is possible to reduce the effects of individual differences in light flux-applied power characteristics of the light sources, changes in temperature, changes over time, and the like. Can be reduced, and at the same time, it is possible to prevent the color tone from being changed due to temperature, aging, and the like.

In addition, in the example of FIG. 2, one of the light sources is always turned on, but all the light sources may be turned off at the time of switching of the frame period, etc. There is an effect that deterioration of the moving image quality due to the afterimage effect of the eyes can be improved.

As described above, in the image display device of this example, while controlling the time average value of the luminous flux, the spatial light modulators for red, green, and blue each perform spatial light modulation with a video signal to obtain a spatial light modulator. By combining the image light of each color to obtain a color image, the desired color reproducibility is achieved by setting the chromaticity coordinates of the three primary colors and white, regardless of the chromaticity coordinates of the light source can do. Therefore, even when a light source having different chromaticity coordinates of the three primary colors from the colorimetry followed by the video signal is used, it is possible to substantially improve the color reproducibility of the three primary colors.

FIG. 4 is a block diagram showing a configuration of a video display device according to a second embodiment of the present invention. FIG. 5 is a timing chart showing a method of controlling light sources of respective colors in the video display device of the present embodiment. FIG. 7 is a timing chart showing another control method of the light source of each color in the video display device of the present embodiment. FIG. 7 is a timing chart showing still another control method of the light source of each color in the video display device of the present embodiment. FIG. 4 is a diagram showing an example of a color triangle on a chromaticity diagram according to the CIE1931 standard color system.

As shown in FIG. 4, the image display device of this example includes a light source unit 10, a red light source drive circuit 21, a green light source drive circuit 22, a blue light source drive circuit 23, a spatial light modulator 30, a spatial light modulator 30, Modulator driving circuit 41, red image memory 51, green image memory 52, blue image memory 53, video signal processing circuit 54, 3-1 selection circuit (RGB sequential selection circuit) 56, timing control circuit 62 It is roughly constituted from. The light source unit 10 includes a red light source 11, a green light source 12, a blue light source 13, a color combining optical system 15, and a projection optical system (not shown).

First, with reference to FIG. 4, an optical configuration of the color sequential video display device of this example will be described. FIG. 4 does not show a specific physical arrangement of the optical components.
In the light source unit 10, the red light source 11 emits red light. The green light source 12 emits green light. The blue light source 13 emits blue light. The color combining optical system 15 combines the incident red light, green light, and blue light and sequentially emits the same to the same optical path. The spatial light modulator 30 sequentially spatially modulates the light emitted from the color combining optical system 15 in accordance with the spatial light modulator drive signal from the spatial light modulator drive circuit 41, and emits the light as image light. The image light of each color emitted from the spatial light modulator 30 is sequentially projected on a screen (not shown) via a projection optical system (not shown).

As the red light source 11, the green light source 12, and the blue light source 13, it is preferable to use an LED (Light Emitting Diode). This is because, according to the LED, it is possible to generate monochromatic light of red, green, and blue, and to control the luminous flux by the applied current value, and further, to reduce the response time to several microseconds or less. This is because the light source can be controlled as described later because the frame period is sufficiently short with respect to the frame period of the image to be displayed.
As long as the light source has such characteristics, a light source other than the LED, for example, a laser diode or the like may be used. Further, when LEDs are used as a light source of a color sequential video display device, it is desirable to use a plurality of LEDs for each color because the amount of light per LED is not sufficient.

The dichroic prism, dichroic mirror, fly-eye lens, or the like is used as the color synthesizing optical system 15 for synthesizing the red light, the green light, and the blue light from each light source. At this time, an optical integrator may be used in order to reduce unevenness of light applied to the spatial light modulator 30.

The spatial light modulator 30 changes the light transmittance or the light reflectance of each part of a space of a fixed size according to an image, and includes a TN (Twisted Nematic) liquid crystal panel, a ferroelectric liquid crystal panel, or a DMD. (Digital Micro-mirror Device) or the like is used.
The TN liquid crystal panel utilizes the properties such as optical rotation and birefringence of the light-transmitting substance constituting the pixel. The degree of polarization of each part changes according to the applied video signal voltage value. The panel can be controlled so as to spatially change the magnitude of light passing therethrough.

A ferroelectric liquid crystal panel utilizes birefringence of a substance constituting a pixel, and transitions between two polarization states (ON state and OFF state) according to the polarity of an applied voltage. Is controlled by pulse width modulation (PWM) of the applied voltage.
That is, as the time of the ON state is longer and the time of the OFF state is shorter, the passing light increases. Therefore, the brightness can be adjusted by controlling the time distribution between the ON state and the OFF state.

There are a transmission type and a reflection type in TN liquid crystal panels and ferroelectric liquid crystal panels. In the case of a spatial light modulator using a transmissive liquid crystal panel, polarizers are provided on the light incident side and the light exit side of the liquid crystal panel, respectively. In the case of a spatial light modulator using a reflection type liquid crystal panel, a polarizing beam splitter (PBS) is provided on the light input / output side of the liquid crystal panel.

The DMD is a reflection-type spatial light modulator that has micromirrors for the number of pixels and uses the property that the inclination of the micromirrors changes according to the polarity of the applied voltage. The tilt of the controlled micromirror is in two states (ON state and OFF state), and the brightness of the passing light is controlled by the PWM of the applied voltage.
That is, the longer the ON state time and the shorter the OFF state time, the brighter. Therefore, the brightness is adjusted by controlling the time distribution between the ON state and the OFF state. At this time, a TIR prism (total reflection prism) may be used in order to reduce the decrease in contrast due to the OFF state of the reflected light leaking into the projection optical system.

Next, the circuit configuration of the video display device of this example will be described with reference to FIG. 4 again.
The red light source driving circuit 21, the green light source driving circuit 22, and the blue light source driving circuit 23 drive the red light source 11, the green light source 12, and the blue light source 13, respectively, in accordance with the timing signal from the timing control circuit 62, and adjust their brightness. Control.

At this time, the brightness of the red light source 11, the green light source 12, and the blue light source 13 is controlled by the red light source driving circuit 21, the green light source driving circuit 22, and the blue light source driving circuit 23, respectively. The control may be performed based on the magnitude of the driving power applied to the light source 13 or may be controlled based on the supply time of the driving power.
When the light source of each color is constituted by a plurality of light emitting elements, the brightness may be adjusted by switching the number of light emitting elements of each color.
Alternatively, the brightness may be adjusted by using a filter such as a liquid crystal panel capable of controlling the transmittance of light, an iris mechanism or the like in combination with the light source.
Further, the red light source driving circuit 21, the green light source driving circuit 22, and the blue light source driving circuit 23 may be capable of adjusting the brightness of the light source by external control (not shown).

The spatial light modulator driving circuit 41 sequentially outputs the image of the spatial light modulator 30 according to the red image signal, the green image signal, and the blue image signal from the 3-1 selection circuit (RGB sequential selection circuit) 56. Control the transmittance or reflectance of the space.
The red image memory 51, the green image memory 52, and the blue image memory 53 write and temporarily store the red video signal, the green video signal, and the blue video signal from the video signal processing circuit 54, respectively. The output is output to the 3-1 selection circuit 56.

The video signal processing circuit 54 receives the video signal S1 and performs video signal processing such as synchronization detection, color space conversion, degamma, and correction of characteristics peculiar to the system, and outputs a red video signal, a green video signal, and a blue video signal. Generate a video signal for use.
Here, the correction of the characteristic peculiar to the system means, for example, correction of unevenness of the characteristic of an optical component and control voltage and transmittance (or reflection) required when a liquid crystal panel is used as the spatial light modulator 30. Rate) is a correction when the relationship with the rate is nonlinear.
The video signal processing circuit 54 stores the red video signal, the green video signal, and the blue video signal in the red image memory 51, the green image memory 52, or the blue image memory 53, respectively. The reading control from the image memory 52 and the blue image memory 53 is performed.

The 3-1 selection circuit (RGB sequential selection circuit) 56 is a red video signal read from the red image memory 51, the green image memory 52, and the blue image memory 53 according to the timing control from the timing control circuit 62. , A green image signal and a blue image signal, and sequentially selects one of them to output to the spatial light modulator driving circuit 41.
The timing control circuit 62 includes a red light source driving circuit 21, a green light source driving circuit 22, a blue light source driving circuit 23, a spatial light modulator driving circuit 41, a video signal processing circuit 54, The operation timing of each of the -1 selection circuits 56 is controlled.

Hereinafter, the control and operation of the video display device of this example will be described with reference to FIGS.
First, a first control method of the light source of each color in the video display device of this example will be described with reference to FIG.
In the case of this example, in the video display device shown in FIG. 4, in one frame period, a red video signal (R-video), a green video signal (G-video), and a blue video signal (B-video). Thus, the spatial light modulator 30 is sequentially driven, and the brightness of the red light source 11, the green light source 12, and the blue light source 13 is controlled at each timing.

Now, according to the red image signal, the green image signal, and the blue image signal, the spatial light modulator 30 sets the time for modulating the red light from the red light source 11 to Trr, Tgr, and Tbr, respectively, and modulates the red light to be modulated. Let the light flux be Prr, Pgr, and Pbr, respectively.
Similarly, the spatial light modulator 30 modulates the green light from the green light source 12 in accordance with the red, green, and blue video signals while setting the time to modulate the green light from the green light source 12, respectively. Let the luminous flux of the green light be Prg, Pgg, Pbg, respectively.
Further, in the spatial light modulator 30, the time for modulating the blue light from the blue light source 13 is set to Trb, Tgb, Tbb and the blue light to be modulated by the red, green and blue video signals, respectively. Let the light flux be Prb, Pgb, Pbb, respectively.

When these variables are applied to Expressions (1) and (2), Expressions (3) and (4) are established as in the case of the first embodiment described above, and the three primary colors and the standard white in colorimetry that the video signal follows. The same chromaticity coordinates can be generated, or the desired color reproducibility can be realized.
Note that a period during which the light is turned off may be provided depending on the convenience of controlling the spatial light modulator 30 or the like.

FIG. 6 shows a second control method of the light source of each color in the video display device of this example. In the example of FIG. 5, Trr = Tgr = Tbr = Trg = Tgg = Tbg = Trb = Tgb = Tbb, but as is clear from equation (1), Prr * Trr, Prg * Trg, Prb * Trb , Pgr * Tgr, Pgg * Tgg, Pgb * Tgb, Pbr * Tbr, Pbg * Tbg, and Pbb * Tbb as long as they are constant. For example, as shown in FIG. 6, for example, Prr = Pgr = Pbr, Prg = Pgg = Pbg, Prb = Pgb = Pbb.
By doing so, the applied power becomes constant for each light source, so that it is possible to reduce the effects of individual differences in light flux-applied power characteristics of the light sources, changes in temperature, changes over time, and the like. Can be reduced, and at the same time, it is possible to prevent the color tone from being changed due to temperature, aging, and the like.

As described above, in the above-described image display device, the time average value of the light flux is controlled, and the red light from the red light source, the green light from the green light source, and the blue light from the blue light source are combined. Since a single spatial light modulator for the combined light is used to sequentially perform spatial light modulation based on the video signals for red, green, and blue to obtain a color image, the chromaticity coordinates of the light source Regardless of the above, by setting the chromaticity coordinates of the three primary colors and white, desired color reproducibility can be realized. Therefore, even when a light source having different chromaticity coordinates of the three primary colors from the colorimetry followed by the video signal is used, it is possible to substantially improve the color reproducibility of the three primary colors.

Next, a third control method of the light source of each color in the video display device of this example will be described with reference to a timing chart of FIG.
In the video display device of this example, the order of the video signals for driving the spatial light modulator 30 is the order of the red video signal, the green video signal, and the blue video signal, but the order is not necessarily required. .

In the video display device of this example, when the video signal for red (R-video) is selected, not only the red light source 11 but also the green light source 12 and the blue light source 13 are driven to irradiate the respective color lights to emit green light. When the video signal (G-video) is selected, not only the green light source 12 but also the blue light source 13 and the red light source 11 are driven to irradiate the respective color lights, and the blue video signal (B-video) is generated. When selected, not only the blue light source 13 but also the red light source 11 and the green light source 12 are driven to emit respective color lights.

Now, when attention is paid to a certain pixel, the red video signal, the green video signal, and the blue video signal for controlling the modulation of light of each color corresponding to the pixel of interest in the spatial light modulator 30 are denoted by Vr, Vg, and Vr, respectively. Vb
0 ≤ Vr ≤ 1 ... (9a)
0 ≤ Vg ≤ 1 ... (9b)
0 ≤ Vb ≤ 1 ... (9c)
And

First, a case where the brightness of an image is not emphasized will be described.
The average values of the luminous flux per frame period of the red light, green light, and blue light applied to the target pixel in the spatial light modulator 30 are denoted by Pr, Pg, and Pb, respectively. The variable Prgb is defined as follows.
Prgb = Pr + Pg + Pb
… (10)
Here, Prgb is a light beam of a combined light of red light, green light and blue light, that is, a light beam of white light.

Next, with respect to the pixel of interest, the red light beam, green light beam, blue light beam, and their combined light beams per frame period emitted from the spatial light modulator 30 are denoted by Lr, Lg, Lb, and Lrgb, respectively.
Lr = Pr * Vr ... (11a)
Lg = Pg * Vg ... (11b)
Lb = Pb * Vb ... (11c)
Lrgb = Lr + Lg + Lb ... (11d)
It becomes.

Next, a case where the brightness of an image is enhanced will be described.
When enhancing the brightness of an image, not only the red light is modulated by the red image signal, but also the green light and the blue light are modulated. The green image signal is used not only to modulate the green light, The blue light and the red light are also modulated, and the blue video signal modulates not only the blue light but also the red light and the green light.
Thereby, the brightness of the image emitted from the spatial light modulator 30 is emphasized.

That is, for the pixel of interest, the luminous flux modulated by the red image signal per frame period and emitted from the spatial light modulator 30 is:
(Pr + K * (Pg + Pb)) * Vr ... (12a)
Similarly, a light beam modulated by the green image signal and emitted from the spatial light modulator 30 is:
(Pg + K * (Pb + Pr)) * Vg… (12b)
Similarly, a light flux modulated by the blue video signal and emitted from the spatial light modulator 30 is:
(Pb + K * (Pr + Pg)) * Vb ... (12c)
It becomes. Here, K is a coefficient indicating the degree of enhancing the brightness, and has a value of the following equation.
0 ≤ K ≤ 1 ... (13)

Assuming that the luminous flux of the combined light is Lrgb ′, Lrgb ′ is as follows from the above equations.
Lrgb '= Lrgb + K * (Pr * (Vg + Vb) + Pg * (Vb + Vr) + Pb * (Vr + Vg))
… (14)
That is,
Lrgb '= Lrgb * (1- K) + Prgb (Vr + Vg + Vb) * K… (15)
It is.

Lrgb ≦ Lrgb ′ ≦ 3Lrgb ... (16)
It becomes. As can be seen from equation (15), the brightness is enhanced, but the hue does not change.
As an extreme case, when K = 0, Lrgb ′ = Lrgb, and thus the brightness is not emphasized. Also, when K = 1, Lrgb '= Prgb * (Vr + Vg + Vb), so that the enhancement of the brightness is maximum, but the color is achromatic.

FIG. 8 shows an example of a color triangle when K is used as a parameter on a chromaticity diagram based on the CIE (Commission Internationale de l'Eclairage) 1931 standard color system (so-called XYZ color system).
Numerical values displayed on the spectrum locus indicated by “中” in the figure indicate the wavelength (unit: nm) of light.
As shown in the figure, it can be seen that the color triangle moves inward as the value of K increases.
At this time, the chromaticity coordinates of the white point indicated by the * mark do not move, and each vertex of the color triangle exists on a straight line connecting each vertex of the color triangle and the white point when K = 0. . This indicates that as the value of K increases, the hue does not change but the saturation decreases.

As is apparent from the above description, in the video display device of this example, it is understood that there is a trade-off between brightness and saturation. In this case, the degree of enhancement of the brightness is a matter of product specifications.
Generally, when the viewing environment is bright, a brighter image is preferred. In many presentation applications, the saturation of an image is not so important. In such a case, it is better to emphasize the brightness even if the saturation is reduced.
On the other hand, when viewing video software, saturation is an important factor, and the viewing environment is often darkened. In such cases, it is better to prioritize saturation without emphasizing brightness. Is good.

From these facts, in the video display device of this example, the degree of enhancement of brightness may be adjusted according to the content of the video source and the viewing environment. The degree of brightness enhancement in this case can be adjusted in the red light source driving circuit 21, the green light source driving circuit 22, and the blue light source driving circuit 23 described above. In addition, the degree of brightness enhancement in the light source drive circuit for each color may be externally controllable.

As described above, according to the image display device of this example, when controlling the spatial light modulator in accordance with the red image signal, green light and blue light are also radiated in addition to the red light, and the green light and blue light are irradiated in response to the green image signal. When controlling the spatial light modulator by using the blue light and the red light in addition to the green light, when controlling the spatial light modulator according to the blue video signal, the red light and the green light other than the blue light are used. Is also illuminated, so that the brightness of the image can be emphasized. It is clear that the method for improving the brightness shown in FIG. 7 can be combined with the correction method for obtaining the corrected three primary colors shown in FIGS.

FIG. 9 is a block diagram illustrating a configuration of a video display device according to a third embodiment of the present invention, and FIG. 10 is a timing chart illustrating a method of controlling light sources of respective colors in the video display device of the present embodiment.
As shown in FIG. 9, the image display device of this example includes a light source unit 10A, a red light source drive circuit 21, a green light source drive circuit 22, a blue light source drive circuit 23, a white light source drive circuit 24, a spatial light source Modulator 30, spatial light modulator driving circuit 41, red image memory 51, green image memory 52, blue image memory 53, video signal processing circuit 54, 3-1 selection circuit 56, timing control circuit 63. The light source section 10A includes a red light source 11, a green light source 12, a blue light source 13, a white light source 14, and a color combining optical system 16.

First, an optical configuration of the image display device of this example will be described with reference to FIG. FIG. 9 does not show a specific physical arrangement of the optical components.
In the light source unit 10A, the red light source 11 emits red light. The green light source 12 emits green light. The blue light source 13 emits blue light. The white light source 14 emits white light. The color combining optical system 16 combines the incident red light, green light, blue light, and white light and sequentially emits them to the same optical path. The spatial light modulator 30 sequentially spatially modulates the light emitted from the color combining optical system 16 according to the spatial light modulator drive signal from the spatial light modulator drive circuit 41 and emits the light as image light. The image light of each color emitted from the spatial light modulator 30 is sequentially projected on a screen (not shown) via a projection optical system (not shown).

The same red light source 11, green light source 12, and blue light source 13 as those in the second embodiment shown in FIG. 4 are used.
As the white light source 14, it is desirable to use an LED, like the red light source 11, the green light source 12, and the blue light source 13. This is because the control of the luminous flux is easy, and it is easy to configure an illumination system using a fly-eye lens as disclosed in the above-described related art. In addition, it is also possible to use a discharge lamp or the like as a white light source other than the LED.

The color combining optical system 16 can be constituted by, for example, a cross dichroic prism, a polarization beam combiner, and two polarization unifying means. The lights from the red light source 11, the green light source 12, and the blue light source 13 are color-combined by a cross dichroic prism, and are further integrated into P-polarized light by a polarization unifying unit. The light from the white light source 14 is unified into S-polarized light by another polarization unifying means. Then, a combined light of red light, green light and blue light unified into P-polarized light and white light unified into S-polarized light are combined by a beam combiner. In the case where the spatial light modulator 30 is a liquid crystal panel that requires linearly polarized light as incident light, a polarization unifying means is further disposed on the exit side of the polarization beam combiner. When the spatial modulator 30 is a DMD that does not require polarized light as incident light, a 波長 wavelength plate may be arranged on the exit side of the polarized beam combiner. In this manner, the color combining optical system 16 that combines the light from the red light source 11, the green light source 12, the blue light source 13, and the white light source 14 can be configured.

As the spatial light modulator 30, the same as in the case of the second embodiment shown in FIG. 4 can be used.

Next, a circuit configuration of the video display device of this example will be described with reference to FIG. 9 again. The circuit configuration of the present embodiment is almost the same as that of the second embodiment shown in FIG. 4, except that a white light source 14 and a white light source driving circuit 24 are added.
The white light source driving circuit 24 controls the brightness of the white light source 14 according to the timing signal from the timing control circuit 63.
It should be noted that the white light source 14 may be always turned on at a constant luminous intensity without inputting the timing signal from the timing control circuit to the white light source driving circuit 24.
Further, the white light source driving circuit 24 may be configured to be able to adjust the brightness of the white light source 14 by external control (not shown).

Next, a control method of the light source of each color in the video display device of this example will be described with reference to a timing chart of FIG.
In the video display device of this example, the order of the video signals for driving the spatial light modulator 30 is the order of the red video signal, the green video signal, and the blue video signal, but the order is not necessarily required. .

In the video display device of this example, when the red video signal is selected, the red light source 11 is driven to emit red light, and when the green video signal is selected, the green light source 12 is driven. When the green light is emitted and the blue image signal is selected, the blue light source 13 is driven to emit the blue light, and the white light source 14 is driven to constantly emit the white light.

Now, when attention is paid to a certain pixel, Vr, Vg, and Vb denote the red video signal, the green video signal, and the blue video signal that control the degree of light modulation of the spatial light modulator 30 with respect to the target pixel. In this case, it is assumed that the relationship of the above-described equation (9) holds.
First, a case where the brightness of an image is not emphasized will be described.
The average values of the luminous flux per frame period of the red light, green light, and blue light applied to the target pixel in the spatial light modulator 30 are denoted by Pr, Pg, and Pb, respectively. Also, the variable Prgb is defined as in the above equation (10).

Here, regarding the target pixel, the red light beam, the green light beam, the blue light beam, and their combined light beams per frame period emitted from the spatial light modulator 30 are Lr, Lg, Lb, and Lrgb, respectively. ) To (11d).

Next, a case where the brightness of an image is enhanced will be described.
When enhancing the brightness of an image, not only the red light is modulated by the red video signal, but also the white light is modulated. The green light is modulated not only by the green video signal, but also by the white light. Not only the blue light is modulated by the video signal, but also the white light.
Thereby, the brightness of the image emitted from the spatial light modulator 30 is emphasized.

Now, let Pw be the average value of the luminous flux per frame period of the white light applied to the target pixel in the spatial light modulator.
Here, the color filter or the like is adjusted so that the chromaticity coordinates of the white light from the white light source 14 match the chromaticity coordinates of the combined light of the red light, the green light, and the blue light.
In this case,
Pw = C * (Pr + Pg + Pb)… (17)
There exists a constant C that satisfies the relationship Then, from equation (10), the following equation is established.
Pw = C * Prgb… (18)

Further, for the pixel of interest, the luminous flux modulated by the red image signal per frame cycle and emitted from the spatial light modulator 30 is as follows:
(Pr + K * Pw) * Vr… (19a)
It becomes. Similarly, a light beam modulated by the green image signal and emitted from the spatial light modulator 30 is:
(Pg + K * Pw) * Vg… (19b)
It becomes. Similarly, a light beam modulated by the blue video signal and emitted from the spatial light modulator 30 is:
(Pb + K * Pw) * Vb… (19b)
It becomes. Here, K is a coefficient indicating the degree of enhancing the brightness, and
0 ≤ K ≤ 1 ... (20)
It is.

Now, assuming that the luminous flux of the combined light is Lrgbw, Lrgbw is as follows from the above equations.
Lrgbw = Lrgb + K * Pw * (Vr + Vg + Vb) (21)
That is,
Lrgbw = Lrgb + K * C * Prgb * (Vr + Vg + Vb) (22)
And from now on,
Lrgb ≦ Lrgbw ≦ Lrgb * (1 + 3C)… (23)
It becomes.

That is, as the value of K is increased, the brightness is enhanced and the hue does not change, but the saturation gradually decreases.
Therefore, similarly to the case of the second embodiment, the white light source driving circuit 24 may be controlled so that the degree of brightness enhancement can be adjusted.
It is clear that the brightness can be enhanced by combining the above-described second and third embodiments.

As described above, according to the color sequential video display device of this example, when controlling the spatial light modulator according to the red video signal, white light is also radiated in addition to the red light, and the white light is irradiated according to the green video signal. When controlling the spatial light modulator, white light is also radiated in addition to the green light, and when controlling the spatial light modulator in accordance with the blue video signal, white light is also radiated in addition to the blue light. Therefore, the brightness of the image can be emphasized.

As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and even if there is a design change or the like within a range not departing from the gist of the present invention. Included in the invention. For example, in each embodiment, an optical integrator may be used on the output side of each light source in order to reduce unevenness of light generated from each light source. In the first embodiment, the order of the video signals input to each spatial light modulator may be the order of the red video signal, the green video signal, and the blue video signal. In the second embodiment, the order of the video signals input to the spatial light modulator during one frame period is not limited to the order of the red video signal, the green video signal, and the blue video signal, but may be another order. .

Further, in each embodiment, an example has been described in which the color switching cycle is only once for red, green, and blue in one frame cycle, but the color switching cycle is plural times (for example, red, green, and blue). , Red, green, blue). In each embodiment, one or three spatial light modulators are used. However, the present invention is not limited to this, and two or four or more spatial light modulators may be used. .

It is clear that the present invention can be applied to a head mounted display in addition to the projection type image display device shown in each embodiment. Further, it is apparent that the present invention can be applied to an image display device of a type in which the color of light applied to adjacent pixels on the spatial light modulator is different. Further, it is clear that the present invention is also applicable to a direct-view type liquid crystal display using three primary color LEDs as a backlight light source.

1 is a block diagram illustrating a configuration of a video display device according to a first embodiment of the present invention. 4 is a timing chart illustrating a method of controlling the light source of each color in the video display device of the embodiment. 6 is a timing chart showing another control method of the light source of each color in the video display device of the embodiment. FIG. 6 is a block diagram illustrating a configuration of a video display device according to a second embodiment of the present invention. 4 is a timing chart illustrating a method of controlling the light source of each color in the video display device of the embodiment. 6 is a timing chart showing another control method of the light source of each color in the video display device of the embodiment. 6 is a timing chart showing still another control method of the light source of each color in the video display device of the embodiment. It is a figure showing an example of a color triangle on a chromaticity diagram by CIE1931 standard color system. FIG. 9 is a block diagram illustrating a configuration of a video display device according to a third embodiment of the present invention. 4 is a timing chart illustrating a method of controlling the light source of each color in the video display device of the embodiment. FIG. 11 is a block diagram illustrating a configuration example of a conventional video display device. 9 is a timing chart showing a control method of a light source of each color in a conventional image display device. FIG. 11 is a block diagram illustrating a configuration of an optical system in a video display device of a second conventional example. 9 is a timing chart showing a control method of a light source of each color in a conventional image display device.

Explanation of reference numerals

10,10A light source unit (illumination means)
1,11 red light source 2,12 green light source 3,13 blue light source 6,7,8 spatial light modulator (spatial light modulator)
Reference Signs List 9 image synthesis optical system 14 white light source 15, 16 color synthesis optical system 21 red light source drive circuit 22 green light source drive circuit 23 blue light source drive circuit 24 white light source drive circuit 30 spatial light modulator (spatial light modulator)
31 Red space light modulator drive circuit 32 Green space light modulator drive circuit 33 Blue space light modulator drive circuit 41 Spatial light modulator drive circuit 51 Red image memory 52 Green image memory 53 Blue image memory 54 Video signal processing circuit 55 3 -3 selection circuit 56 3-1 selection circuit 61, 62, 63 Timing control circuit

Claims (14)

A red light source that emits red light,
A green light source that emits green light,
A blue light source that emits blue light,
At least one spatial light modulator for spatially modulating light from the red light source, the green light source, and the blue light source in accordance with the red image signal, the green image signal, and the blue image signal;
Selection control means for selecting a combination of a video signal and light to be modulated to control the spatial light modulation means,
An image display device comprising: a light amount control unit that controls a time average value of a light flux of light modulated by the spatial light modulation unit. In the spatial light modulator, Lrr is the time average of the light flux of the red light modulated according to the video signal for red, Lgr is the time average of the light flux of the red light modulated according to the video signal for green, The time average value of the red light beam modulated according to the signal is Lbr, the time average value of the green light beam modulated according to the red video signal is Lrg, and the green light beam modulated according to the green video signal is Lrg. The time average value of the light beam is Lgg, the time average value of the green light beam modulated according to the blue video signal is Lbg, and the time average value of the blue light beam modulated according to the red video signal is Lrb, green The time average value of the light flux of blue light modulated according to the video signal for blue is Lgb, the time average value of the light flux of blue light modulated according to the video signal for blue is Lbb, and the red light, green light and blue light are CIE (Commission Internationale de l'Eclairage) 1931 Standard Table When the chromaticity coordinates of the color system are (xr, yr), (xg, yg), and (xb, yb), respectively, the chromaticity coordinates of the standard color system of red, green, and blue in the colorimetry that the video signal follows. (xr0, yr0), (xg0, yg0), (xb0, yb0), the time average of the red light, green light, and blue light, and the standard color specification of the red light, green light, and blue light Xr0 = (xr * Lrr / yr + xg * Lrg / yg + xb * Lrb / yb) / (Lrr / yr + Lrg / yg + Lrb / yb)
yr0 = (Lrr + Lrg + Lrb) / (Lrr / yr + Lrg / yg + Lrb / yb)
xg0 = (xr * Lgr / yr + xg * Lgg / yg + xb * Lgb / yb) / (Lgr / yr + Lgg / yg + Lgb / yb)
yg0 = (Lgr + Lgg + Lgb) / (Lgr / yr + Lgg / yg + Lgb / yb)
xb0 = (xr * Lbr / yr + xg * Lbg / yg + xb * Lbb / yb) / (Lbr / yr + Lbg / yg + Lbb / yb)
yb0 = (Lbr + Lbg + Lbb) / (Lbr / yr + Lbg / yg + Lbb / yb)
2. The image display device according to claim 1, wherein the following relationship is satisfied. In the video display device,
Lr = Lrr + Lrg + Lrb
Lg = Lgr + Lgg + Lgb
Lb = Lbr + Lbg + Lbb
In the colorimetry that the video signal follows, the chromaticity coordinates (xr0, yr0), (xg0, yg0), (xb0, yb0) according to the standard color system of red, green, and blue, and the colorimetry that the video signal follows Between the chromaticity coordinates (xw, yw) of the standard white color in the CIE1931 standard color system, xw = (xr0 * Lr / yr0 + xg0 * Lg / yg0 + xb0 * Lb / yb0) / (Lr / (yr0 + Lg / yg0 + Lb / yb0)
yw = (Lr + Lg + Lb) / (Lr / yr0 + Lg / yg0 + Lb / yb0)
3. The image display device according to claim 2, wherein the following relationship is satisfied. In the spatial light modulating means, Lrr is the time average of the light flux of the red light modulated according to the video signal for red, Lgr is the time average of the light flux of the red light modulated according to the video signal for green, The time average value of the red light beam modulated according to the signal is Lbr, the time average value of the green light beam modulated according to the red video signal is Lrg, and the green light beam modulated according to the green video signal is Lrg. The time average value of the light beam is Lgg, the time average value of the green light beam modulated according to the blue video signal is Lbg, and the time average value of the blue light beam modulated according to the red video signal is Lrb, green The time average value of the light flux of blue light modulated according to the video signal for blue is Lgb, the time average value of the light flux of blue light modulated according to the video signal for blue is Lbb, and the red light, green light and blue light are CIE (Commission Internationale de l'Eclairage) 1931 Standard Table Let the chromaticity coordinates of the color system be (xr, yr), (xg, yg), (xb, yb), and Lr, Lg, Lb, xr1, yr1, xg1, yg1, xb1, yb1 Equation Lr = Lrr + Lrg + Lrb
Lg = Lgr + Lgg + Lgb
Lb = Lbr + Lbg + Lbb
xr1 = (xr * Lrr / yr + xg * Lrg / yg + xb * Lrb / yb) / (Lrr / yr + Lrg / yg + Lrb / yb)
yr1 = (Lrr + Lrg + Lrb) / (Lrr / yr + Lrg / yg + Lrb / yb)
xg1 = (xr * Lgr / yr + xg * Lgg / yg + xb * Lgb / yb) / (Lgr / yr + Lgg / yg + Lgb / yb)
yg1 = (Lgr + Lgg + Lgb) / (Lgr / yr + Lgg / yg + Lgb / yb)
xb1 = (xr * Lbr / yr + xg * Lbg / yg + xb * Lbb / yb) / (Lbr / yr + Lbg / yg + Lbb / yb)
yb1 = (Lbr + Lbg + Lbb) / (Lbr / yr + Lbg / yg + Lbb / yb)
When defined by chromaticity coordinates (xw, yw) of the standard white color system in colorimetry that the video signal follows, the following expression xw = (xr1 * Lr / yr1 + xg1 * Lg / yg1 + xb1 * Lb / yb1) / (Lr / yr1 + Lg / yg1 + Lb / yb1)
yw = (Lr + Lg + Lb) / (Lr / yr1 + Lg / yg1 + Lb / yb1)
2. The image display device according to claim 1, wherein the following relationship is satisfied. In the image display device, the luminous fluxes of the red light modulated by the red image signal, the green image signal, and the blue image signal are Prr, Pgr, and Pbr, respectively, and the red image signal, the green image signal, and the blue image signal When the luminous flux of the green light modulated by Pg is Pg, Pgg, and Pbg, respectively, and the luminous flux of the blue light modulated by the red video signal, the green video signal, and the blue video signal is Prb, Pgb, and Pbb, respectively,
Prr = Pgr = Pbr
Prg = Pgg = Pbg
Prb = Pgb = Pbb
The image display device according to any one of claims 1 to 4, wherein the following relationship is satisfied. The video display device according to any one of claims 1 to 5, wherein a period in which all light sources of each color are turned off during one frame period is provided in the video display device. An image display comprising: an illuminating unit that adjusts respective luminous fluxes of red light, green light, and blue light, sequentially switches the light and sequentially emits the light, and a spatial light modulating unit that spatially modulates light from the illuminating device In the device,
The luminous flux of red light emitted when the spatial light modulating means is driven by the red image signal is Pr, the luminous flux of green light emitted when the spatial light modulating means is driven by the green image signal is Pg, and the When the luminous flux of the blue light irradiated at the time of driving the spatial light modulating means is Pb, the luminous flux K * Pg (K is a coefficient (0 ≦ K ≦ 1) together with the red light when the spatial light modulating means is driven by the red image signal. , The same applies hereinafter) green light and the blue light of the light flux K * Pb to the spatial light modulating means. When the spatial light modulating means is driven by the green image signal, the blue light of the light flux K * Pb is emitted together with the green light. And the red light of the light flux K * Pr is applied to the spatial light modulating means, and when the spatial light modulating means is driven by the blue image signal, the red light of the light flux K * Pr and the green light of the light flux K * Pg together with the blue light. And irradiate the spatial light modulating means with light. A video display device configured to control the lighting means. 8. The video display device according to claim 7, wherein the lighting unit is configured to change a value of the coefficient K. An image display comprising: an illuminating unit that adjusts respective luminous fluxes of red light, green light, and blue light, sequentially switches the light and sequentially emits the light, and a spatial light modulating unit that spatially modulates the light from the illuminating device. In the device,
When the spatial light modulator is driven by the red image signal, the spatial light modulator is irradiated with red light and white light, and when the spatial light modulator is driven by the green image signal, the green light and white light are converted into the spatial light. Irradiating the spatial light modulating means with the blue light and white light when the spatial light modulating means is driven by the blue image signal. Video display device. The white light is irradiated to the spatial light modulator in accordance with the driving timing of the spatial light modulator by the red image signal, the green image signal, and the blue image signal. The video display device according to claim 9. 10. The image display device according to claim 9, wherein the white light is always turned on. The image display device according to any one of claims 9 to 11, wherein the brightness of the white light can be changed by external control. 13. The image display device according to claim 1, wherein the light source of the red light, the green light, the blue light, and the white light comprises an LED (Light Emitting Diode). 14. The image display device according to claim 13, wherein the LED includes a plurality of LEDs.

Images