JP2006039520A - Liquid crystal display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in a liquid crystal display device which displays images by using birefringence of liquid crystal, that color tone or decreases in color purity are caused at high luminance and low luminance owing to disorder of wavelength dispersion characteristics of refractive indey anisotropy that a liquid crystal material has and additive color mixing property which is remarkable at low-gradation display. <P>SOLUTION: A liquid crystal display apparatus having first white color light sources 20 and blue and/or red second coloring light sources 30 disposed on a back side of a liquid crystal panel 10, and an image quality processing calculation circuit 2 for detecting a brightness of input image signals, in accordance with a detection result, controlling intensities of the first white color light sources and/or second coloring light sources and correcting pixel signals to be supplied to the liquid crystal panel 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention dimmes a light source (backlight) according to the brightness of an image signal and optimizes an image to be displayed, thereby reducing a change in color tone between gradations, from low luminance to high luminance. The present invention relates to a liquid crystal display device that can display high-quality images by maintaining high color purity.

  Compared with the CRT (Cathode Ray Tube), which has been the mainstream of display devices, the liquid crystal display has the advantage that it can be made thinner and lighter, and its application has been expanded with the development and progress of viewing angle expansion technology and video technology. I came.

  In recent years, with the expansion of applications as desktop personal computer monitors, printing and design monitors, or liquid crystal televisions, liquid crystal displays can be used for halftones such as blue, green, and red color purity and human face color. There is an increasing demand for color reproducibility. In particular, for use as a liquid crystal television, a particularly high contrast ratio is required, and color reproducibility from low luminance to high luminance is required as well as a wide dynamic range in luminance. However, the liquid crystal display device has a problem that the color tone is likely to change with a change in luminance, that is, a change in gradation.

  In order to achieve high brightness and high color purity, a technique for operating in two different modes of operation of a color purity mode and a high brightness mode using a plurality of types of light sources having different emission colors is described in Patent Document 1 below. Yes. Further, as a technique for improving the moving image response characteristics and achieving high brightness, a configuration having a cold cathode fluorescent lamp and a light emitting diode array is described in Patent Document 2 below.

JP 2003-331608 A JP 2003-140110 A

  In a liquid crystal display device, particularly a monitor for printing and design, the difference in color tone between gradations is a serious problem. In addition, in a liquid crystal television, it is necessary to expand the dynamic range of luminance as well as color reproducibility. However, in a liquid crystal display device that displays using the birefringence of liquid crystal, the higher order due to the influence of the wavelength dispersion characteristic of the refractive index anisotropy of the liquid crystal material and the depolarization component existing between the pair of polarizing plates. There arises a problem that the color purity is lowered at the time of tone or low gradation.

  On the other hand, there is also the influence of human visual perception. When viewing a movie-like image with low average brightness (APL) in a low-light environment, the human visual perception is significantly less saturated in red due to Purkinje's phenomenon. I feel the color is bright. Under such conditions, due to the characteristics of the polarizing plate, the influence of the depolarizing member, etc., the color purity of red is significantly reduced, and images with achromatic colors such as gray and black, and human facial colors are bluish Will be visually recognized.

  In addition, due to the characteristics based on the principle of the liquid crystal display mode, a tone shift to blue at low luminance occurs. For example, the transmittance T in the vertical alignment mode is expressed by the following equation.

^{T = 1/2 (sin 2} (πΔnd)) - 1/2 (sin 2 (πΔnd / λ))
Here, Δn represents the refractive index anisotropy of the liquid crystal, d represents the thickness of the liquid crystal layer, and λ represents the wavelength.

  In the case of the vertical alignment mode, the effective Δnd changes when the orientation of the liquid crystal molecules is tilted by the application of an electric field, and the transmittance is controlled by this effective Δnd change. In the case of the normally closed method, the transmitted light intensity of the short wavelength is high when the gradation is low, and the transmitted light intensity of the long wavelength is high when the gradation is high. Even if the halftone color tone can be controlled by independently controlling the transmittance of the blue, green, and red pixels of the liquid crystal panel, it is possible to compensate for the bluish black due to the influence of the members and human visual perception, Since the transmitted light intensity of blue becomes low, high brightness white cannot be realized.

  Japanese Patent Application Laid-Open No. H10-228561 discloses means for adjusting white chromaticity by controlling light sources having different emission colors. According to this technique, the color purity at the time of high luminance is increased, but there is no effect on the decrease in color purity at the time of low luminance. In addition, a technique for expanding the dynamic range of luminance using a cold cathode fluorescent lamp and a light source by a light emitting diode array in order to improve moving image characteristics is disclosed in Patent Document 2 described above, and this technique achieves high color purity. I can't do it.

  Thus, high color purity at high brightness has been discussed so far, but high contrast is achieved by maintaining high color purity and expanding the dynamic range of brightness from high brightness to low brightness. No mention is made of the issue of achieving the ratio.

  Accordingly, an object of the present invention is to provide a liquid crystal display device that can display luminance in a wide dynamic range and can maintain high color purity from low luminance to high luminance.

  The present invention will be described with reference to the reference numerals shown in FIGS.

In the present invention, as a light source disposed on the back side of the liquid crystal panel 10, a first white light source 20 composed of red, green, and blue components that are the three primary colors of light, and red, green, and blue that are the three primary colors of light. A brightness detection circuit 1 configured to include at least one component and a second colored light source 30 that independently emits light, and detects an average brightness, a maximum brightness, a minimum brightness, and the like of an input image signal, and a detected brightness Accordingly, an image quality processing arithmetic circuit 2 that outputs a light source control signal for controlling the intensity of the light sources 20 and 30 and an image control signal for controlling a display image on the liquid crystal panel 10, and the first white light source 10 based on the light source control signal. And the second coloring light source 20 and an image control circuit 4 for displaying an image optimized on the liquid crystal panel 10 based on the image control signal.

  The liquid crystal display device according to the present invention can prevent yellowing of the white display when displaying the maximum luminance, can display an achromatic white, can display a high luminance blue, and can display a low luminance. In addition, display with high color purity is possible by suppressing blue discoloration and a decrease in red color purity.

  In addition, an example of the embodiment of the present invention is a transmissive liquid crystal display device including a light source on the back side of the liquid crystal panel 10. The light source is a first white light source 20 showing almost white and a liquid crystal panel directly below. It is a transmissive liquid crystal display device comprising a second colored light source 30 showing red and / or blue color on at least one side of the light guide plate 32 arranged. The white light source here is not a definition of strict achromatic white in color engineering, but generally refers to a light source used as a light source of a liquid crystal display. For example, a light source having a color temperature of 5000K to 15000K is used as a light source of a liquid crystal display, and the light source in this range is configured as a first white light source.

  The image quality processing arithmetic circuit 2 in the present invention includes a light source control and image control look-up table, and the light source control look-up table is based on the brightness of the image signal and the transmission characteristics of the liquid crystal panel 10. A light source control signal for dimming the light source is generated with reference to the image, and an image control signal for controlling a display image on the liquid crystal panel is generated with reference to a look-up table for image control.

  The present invention is further characterized in that the first white light source 20 and the second colored light source 30 of red and / or blue are both disposed directly under the liquid crystal panel.

  At this time, the second colored light source 30 is preferably disposed between the first white light sources 20. For example, the light emitting diode array is arranged close to the first white light source, and another structure is arranged such that red and blue light emitting diodes are scattered.

  In order to mix light from the first white light source 20 and the second colored light source 30, it is preferable to dispose the diffusion plate 33 between the liquid crystal panel 10 and the light source storage unit 31.

  In the present invention, the first white light source 20 housed in the backlight case 21 uses a narrow-band light-emitting fluorescent tube, a light-emitting diode, and an organic electroluminescence element (hereinafter referred to as “organic EL”). Similarly, the second colored light source 30 uses a red and / or blue narrow-band light emitting type fluorescent tube, a red and / or blue light emitting diode, and a red and / or blue organic EL. .

  Furthermore, another configuration of the present invention is characterized in that a white pixel is added to the red, green, and blue pixels of the liquid crystal panel 10 and four pixels are used as a basic pixel unit.

  The four-pixel liquid crystal panel 10 is irradiated with backlights from the first white light source 20 and the second colored light source 30, and the display image has a very high luminance required by computer graphics or the like. It is preferable when displaying.

  In addition, the present invention is characterized by including a surrounding environment brightness detection circuit 5 that detects the brightness of the surrounding environment where the liquid crystal display device is placed.

  In the liquid crystal display device according to the present invention, processing calculation is performed according to the average luminance, maximum luminance, and minimum luminance of the input image signal, and the color tone and intensity of the light source are controlled, and the image displayed on the liquid crystal panel is controlled. As a result, a high-quality liquid crystal display device can be provided. In addition, the present invention can be applied to all liquid crystal display devices such as liquid crystal televisions which are normally closed type liquid crystal displays in a display mode utilizing the birefringence of liquid crystal and particularly require color reproducibility and high contrast ratio. it can.

FIG. 1 is a schematic view showing an example of a liquid crystal display device according to the present invention. The light source provided on the back side of the liquid crystal panel 10 has a first white light source 20 that shows a substantially white color stored in the backlight case 21 and red and / or blue colors stored in the light source storage unit 31. The second coloring light source 30 shown in FIG. The second colored light source 30 is provided on at least one side of the light guide plate 32 disposed on the back surface of the liquid crystal panel 10. The light guide plate 32 is for irradiating light from the first white light source 20 and the second colored light source 30 on the back surface of the liquid crystal panel 10 and transmitting the light to the front surface. A diffusing plate 33 is provided between the liquid crystal panel 10 and the light guide plate 32 to mix and equalize light from the light source (backlight).

  FIG. 2 is an example of a configuration diagram of the liquid crystal display device according to the present invention. The brightness detection circuit 1 detects the average luminance, maximum luminance, minimum luminance, and the like of the input image signal, and the detection result. Is supplied to the image quality processing arithmetic circuit 2. The image quality processing arithmetic circuit 2 supplies a light source control signal to the light source control circuit 3 and an image control signal to the image control circuit 4 based on the detected result. The light source control circuit 3 controls lighting of the first white light source 20 and the second colored light source 30 based on the light source control signal. Further, the image control circuit 4 displays an image to be displayed on the liquid crystal panel 10 based on an image control signal (a signal including a corrected image signal and a horizontal / vertical synchronization signal for scanning the liquid crystal panel 10). . These controls are implemented in the following examples.

  FIG. 3 is obtained by adding a surrounding environment brightness detection circuit 5 that detects the brightness of the surrounding environment in which the liquid crystal display device is installed to FIG.

This is human vision perception when it is a dim environment where the illuminance is several tens of lux or less, and when it is observed in a dark room state, it is dark place vision. Human vision perception differs from photopic vision when viewed in a normal bright environment, because the wavelength at which light is most sensitively detected is 550 nm in photopic vision, but changes to 507 nm in dark vision. It is. In mesopic vision, it is considered that it is close to 507 nm in scotopic vision, although the visibility characteristic has not yet been determined.

  Accordingly, since the human environment looks different in a bright environment and a dark environment, the brightness of the surrounding environment is detected by the surrounding environment brightness detection circuit 5, and based on the detection result, the image quality arithmetic processing circuit 2 performs light source control. By controlling the circuit 3 and the image control circuit 4, a display image suitable for the environment can be obtained.

  Next, a basic concept of control performed by the image quality processing arithmetic circuit 2 will be described with reference to FIGS.

  FIG. 4 shows an example of the relationship between the voltage applied to the liquid crystal panel and the brightness. This is an example of the case where the effective Δnd changes with the electric field strength as in the vertical alignment mode. Focusing on the intensity ratio of blue, green, and red, when the electric field is low, that is, low luminance, the intensity of blue and green is strong in blue or similar to that of green. It can be seen that the intensity of blue is significantly reduced. This means that if you try to display high brightness, the intensity of blue will be insufficient, so yellowness will increase, or you will be forced to choose either the maximum brightness that matches the intensity of blue where intensity is insufficient. become.

  FIG. 5 shows an example of spectral characteristics at the time of high luminance display and black to low luminance display in a liquid crystal panel of a birefringence display system. Note that the scale of the transmitted light intensity on the vertical axis is arbitrary, and comparing the maximum and minimum spectral characteristics, the black to low luminance display is 500 nm or less, that is, the intensity of blue is strong, and the high luminance display is 600 nm. It can be seen that the strength in the vicinity is high. From this, it can be seen that the liquid crystal panel has a characteristic of being blue in black to low luminance and yellow in high luminance.

  Therefore, when the average luminance (APL) of the image signal is low, only the first white light source 20 is lit, and in the case of high luminance display, the blue of the second colored light source 30 is lit, and the color of the light source Increase the temperature. As described above, the image quality calculation processing circuit 2 controls the color temperature of the light source and outputs an image control signal corresponding to the color temperature, whereby it is possible to suppress a decrease in blue intensity.

At this time, when the fluorescent tube is used for blue of the second coloring light source 30 and when the light emitting diode or organic EL is used, the luminance control range of the fluorescent tube is narrower than that of the light emitting diode or organic EL. Therefore, it is not necessary to control the blue color of the second colored light source 30 so as to be remarkably strong, and the fluorescent light tube can sufficiently compensate.

  In addition, it is generally said that the fluorescent tube is turned on / off slowly, but the fluorescent tube that uses green phosphors is the slowest so that the speed actually becomes a problem. Blue and red phosphors are used. The lighting and extinguishing speed of the fluorescent tube is very fast.

For example, when LaPO ₄ : Tb, Ce is used as an example of a green phosphor, the rising (lighting) speed is about 5 milliseconds and the falling (light-off) speed is about 6 milliseconds. BAM: Eu, which is an example of the phosphor, is 0.1 milliseconds or less for both rising and falling, and Y ₂ O ₃ : Eu, which is an example of the red phosphor, is about 3 milliseconds or less.

  Therefore, when the backlight is blinked to improve the video, if the response is 4 milliseconds or less, it is said that human visual perception is not sensitive. There is no problem.

  As described above, a configuration using a fluorescent tube is effective as the second colored light source 30 which is one of the configuration examples of the present invention. However, the first white light source 20 can also be dimmed when the surrounding environment is dark and the average luminance of the image signal and the maximum luminance are sufficiently low. This dimming may be current control or frequency modulation. These determinations may be performed by the arithmetic processing circuit 2. In this way, blue intensity compensation can be performed.

  Next, a case where red intensity compensation is performed will be described. Red is mainly required for low-luminance image signals. As shown in FIG. 5, even when black is displayed, the liquid crystal panel transmits blue light to some extent. This has an influence of a polarization removing member such as a polarizing plate or a color filter disposed between the polarizing plates. Therefore, even when red is displayed in the low luminance display, blue and green transmitted light are mixed, and the color purity of red is significantly lowered. Therefore, in the case of low-luminance display, the image quality processing arithmetic circuit 2 performs processing so that the intensity of the first white light source 20 is dimmed and lowered, and the second colored light source 30 is lit red. The

There is also a problem of human visual perception as shown in FIG. This is because, as described above, a so-called Purkinje phenomenon occurs in which the blue light is strong and the red light is difficult to detect in a dark environment. Therefore, based on the detection result from the detection circuit 5 that detects the brightness of the surrounding environment, the image quality processing arithmetic circuit 2 reduces the intensity of the first white light source 20 and performs the second coloring when the surrounding environment is dark. The light source 30 is controlled to be turned on. However, even if the surrounding environment is dark, if the average luminance of the image signal is sufficiently high, the Purkinje phenomenon disappears. In this case, control for reducing the intensity of only the first white light source may be performed.

About compensation of blue and red, you may have both, and it is good also as a structure which consists only of either one. For example, when using a liquid crystal panel with sufficiently strong bluishness, the second coloring light source 30 may be configured to be only red, or the color temperature of the first white light source 20 may be set low, and the second Alternatively, the color light source may be blue only.

  As another configuration, there is a configuration in which the second colored light source 30 is always turned on and dimmed. That is, the intensity of green in the first white light source 20 is increased, blue and red as the second colored light source 30 are always lit, the color temperature is controlled, and a low-brightness and high-brightness image is obtained. When a signal is detected, the intensity of the second colored light source 30 is dimmed by the image quality processing arithmetic circuit 2. Increasing the intensity of green with the first white light source 20 is advantageous from the standpoint of efficiency, and is a configuration in which the luminance of the light source can be particularly increased.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

In this embodiment, the light source provided on the back surface of the liquid crystal panel 10 in FIG. 1 is a cold cathode fluorescent light having a diameter of 2 mm made of a narrow-band phosphor type phosphor as the first white light source 20 disposed immediately below the liquid crystal panel 10. The tubes are arranged in parallel in the backlight case 21, and a red cold cathode fluorescent tube stored in the light source storage unit 31 is used as the second colored light source 30 as a light guide plate (ZEONOR manufactured by ZEON Corporation) 32. It was arranged on each of the two sides. A diffusion plate 33 is disposed between the light guide plate 32 and the liquid crystal panel 10.

  Since the intensity of the second colored light source 30 does not need to be as strong as that of the first white light source 20, by using a light guide plate type, the number of second colored light sources 30 can be reduced to reduce power consumption, and The degree of color mixing is also improved. In the present embodiment, the second colored light source 30 is arranged on the short side of the liquid crystal panel 10, but in the case of the light guide plate type, it may be arranged on the long side. In the present embodiment, the liquid crystal panel 10 is a 32 inch type in a horizontal electric field display mode. Twelve first white light sources 20 were used. Two second colored light sources 30 were arranged on both sides.

  In FIG. 2, when the average luminance of the input image signal is 33 gradations (in this embodiment, the minimum is 0 gradation and the maximum is 255 gradations), or the average luminance of the input image signal Is 32 gradations or less and the maximum luminance is 162 gradations or more, the image quality processing arithmetic circuit 2 sends a light source control signal for turning on only the first white light source 20 to the light source control circuit 3. To give.

  When the average luminance of the input image signal is 32 gradations or less and the maximum luminance is 161 gradations or less, the image quality processing arithmetic circuit 2 refers to the look-up table for image control, The gamma characteristic of the image signal is corrected, and the corrected image signal and an image control signal including a horizontal / vertical synchronization signal for scanning the liquid crystal panel 10 are supplied to the image control circuit 4, and at the same time, a lookup table for light source control is provided. With reference to the light source control circuit 3, a light source control signal for lighting the red fluorescent tube which is the second colored light source 30 is given.

  Here, FIG. 7 shows the light emission characteristics of the light source when only the first white light source 20 is turned on and when the red fluorescent tube which is the second colored light source 30 is turned on. The amount of increase in red emission intensity when the fluorescent tube is turned on is indicated by a double-pointed arrow. The image quality processing arithmetic circuit 2 includes a light source control look-up table corresponding to the light emission characteristics.

[Comparative Example]
A typical example when the above control is not performed will be described with reference to the chromaticity diagram of FIG.

  First, in FIG. 25, the chromaticity coordinates of NTSC television signals are generally red (R) (0.67, 0.33), green (G) (0.21, 0.71), and blue (B). (0.14, 0.08) is defined, and the area of the triangle surrounded by the chromaticity coordinates is the colorimetric range of the NTSC television signal.

  Usually, the liquid crystal display device has a color range at the time of high luminance shown in FIG. 25 having a color range of 72% with respect to the color range of NTSC. That is, when the primary colors of RGB are displayed at the maximum luminance, red is (0.64, 0.32), green is (0.29, 0.61), and blue is (0.14, 0.078). ). This is a chromaticity coordinate when the maximum luminance of each color is displayed.

However, in the case of a liquid crystal display device, this color specification range cannot be maintained at low luminance. For example, red (0.47, 0.27) and green (0.28, 0.51) shown in FIG. The blue color range is (0.13, 0.10) when the luminance is low. In this color range at low luminance, red and green are decreasing, but red is recognized by the human eye when the color purity is most deteriorated. This is because the color difference recognized by the human eye is not evenly spaced on the xy chromaticity diagram, and red is conspicuous, but the decrease in green is relatively difficult to recognize.

  On the other hand, white and black chromaticity coordinates are also different. Usually designed to adjust white chromaticity. In FIG. 25, the chromaticity coordinates of white are set to (0.28, 0.29), and the achromatic color on the chromaticity diagram, for example, the chromaticity coordinates (0.3101 of the standard light source C under daylight conditions). , 0.3161), the color is slightly bluish white. However, this is a chromaticity that is generally set according to the user's preference because the preference is very different.

  The problem is that the black display becomes very bluish compared to the set white. In FIG. 25, the chromaticity coordinates of black are (0.23, 0.21), resulting in a bluish display.

  An object of the present invention is to improve the above two problems, namely, that the color purity of red is deteriorated at low luminance and that the black display is bluish. That is, the target values are to bring red at low luminance close to the coordinates of red at high luminance, and to bring black chromaticity closer to white chromaticity.

  The present embodiment will be described with reference to the chromaticity diagram shown in FIG. 25. The chromaticity coordinates of the first white light source 20 of the present embodiment are (0.28, 0.26). The intensity of the second colored light source 30 is about 0.25 with respect to the red emission intensity of the first white light source 20, that is, the emission intensity at 612 nm. As a result, the chromaticity (x, y) of red below the gradation 32 becomes (0.51, 0.28), which is an improvement over (0.47, 0.27) when the second coloring light source is not used. To do.

  In this embodiment, the reference gradation range is set to gradation 32 or less, but the original gamma characteristic of the liquid crystal panel used, the color temperature of the white light source, the characteristics of the polarizing plate and color filter used for the liquid crystal panel, etc. Therefore, it is only necessary to optimize the gradation range corresponding to each, and it is needless to say that the gradation range is not limited to this embodiment.

  A condition for dimming a red light source as the second coloring light source is added to the first embodiment. When the average luminance of the input image signal is 32 gradations or less and the maximum luminance is 88 gradations or less, the intensity of the first white light source is reduced to ½, and the second colored light source The intensity of the red light source is adjusted so as to be about 0.7 with respect to the intensity at 612 nm when the first white light source is fully lit.

  FIG. 8 shows the emission characteristics in this case, and the emission intensity at a wavelength of 612 nm increases by about 70% with respect to the emission intensity at 544 nm. In the same figure, the light emission characteristic when the first white light source is fully lit is shown by a thin line, and the light emission characteristic when the intensity of the first white light source is reduced to 1/2 and the second red colored light source is turned on. Shown in bold lines.

  This light emission characteristic is stored in a look-up table for light source control in the image quality processing arithmetic circuit 2, and when the input image signal is in the gradation range of this embodiment, the image quality processing arithmetic circuit 2 Referring to the control look-up table, the intensity of the first white light source is reduced to ½, and the intensity of the red light source as the second coloring light source is 612 nm when the first white light source is fully lit. The light source control circuit 3 is instructed to dim the light so that the intensity of the light is about 0.7.

  At this time, red chromaticity (x, y) of gradation 32 or less becomes (0.55, 0.29), and the color purity of red is greatly improved. In the case of the maximum luminance of red, it can be seen that it can be greatly improved considering (0.64, 0.32).

In addition, regarding the color feeling in black display, when the correction of the present embodiment is not applied,
While (0.22, 0.22), it is (0.29, 0.22), which can be greatly improved. Further, comparing the brightness and brightness in black display, the brightness of black display without correction is 1.1 cd / m ² , whereas the brightness of black display in this embodiment is 0.73 cd / m 2. It becomes ^2, thereby the contrast ratio improvement because it reduced by about 30%.

  In the present embodiment, in addition to the second embodiment, when the brightness (illuminance) of the surrounding environment is 50 lux or less, the intensity of the first white light source is halved and the second red colored light source is turned on. To do. At this time, the same light source control as in FIG. 8 is performed for the light emission characteristics when the average luminance of the input image signal is 32 gradations or less and the maximum luminance is 88 gradations or less.

  In addition to this, when the average luminance is 33 gradations or more, or the maximum luminance is 89 gradations or more, the light emission characteristics shown in FIG. 9 are obtained. The intensity of the red light source, which is the second colored light source, is adjusted to be about 0.3 with respect to the intensity at 612 nm when the first white light source is fully lit. In this case, the emission intensity at a wavelength of 612 nm increases by about 15% with respect to the emission intensity at 544 nm.

  The present embodiment provides a liquid crystal display device that takes into account the color appearance when the human visual perception from light vision to dark vision is the spectral visibility characteristic indicated by the wavy line in FIG. In the liquid crystal display device of the present embodiment, the chromaticity of black display is visually recognized as (0.28, 0.25), and it becomes possible to feel a more achromatic black. Similarly, the low chromaticity of red, which is (0.60, 0.22), is visually recognized as a chromaticity equivalent to the color range at the time of high luminance. The decrease in color purity can be dramatically improved.

  In this embodiment, a red light emitting diode is used as the second colored light source 30. An outline of the light source unit is shown in FIG. Three light emitting diodes were arranged on each side. In addition, although a present Example is a number with respect to the magnitude | size of a 28-inch liquid crystal panel, when using a larger liquid crystal panel than this, it has shown the structure arrange | positioned 10 pieces on both sides in FIG. Thus, the number may be increased as appropriate.

  In this embodiment, the chromaticity coordinates of the first white light source are (0.26, 0.23). Eight fluorescent tubes were used. The intensity of the second colored light source is reduced to 1/2 when the average luminance of the input image signal is 32 gradations or less and the maximum luminance is 88 gradations or less. The second coloring light source (red) is changed according to the gradation as shown in FIG. Thereby, the chromaticity coordinates of the light source can be arbitrarily controlled from the chromaticity coordinates described above to (0.34, 0.24).

  The liquid crystal panel used was a horizontal electric field type liquid crystal panel, which was a display mode using a fringe electric field, and a liquid crystal panel in which Δnd was set to 0.4 μm was used. This liquid crystal panel exhibits the spectral characteristics of FIG. In FIG. 5, the influence of the color filter is excluded, and the spectrum of only the liquid crystal layer is shown. While this liquid crystal panel can increase the transmitted light, as shown in FIG. 5, the blue transmittance phenomenon is remarkable at high luminance.

  In the present embodiment, this problem is solved by controlling the image quality so as to perform high luminance display using only the first white light source. That is, the chromaticity coordinates of white are (0.28, 0.28), and rather, pale white can be expressed.

  At the time of low gradation, the intensity of red is sequentially increased and correction is performed for each gradation. Comparing with black display, by setting the chromaticity coordinates of the light source to (0.34, 0.24) (maximum red of the second colored light source), the chromaticity coordinates of black are (0.28, 0.24). 21). If the compensation of the present embodiment is not performed, the chromaticity coordinates of black will be (0.22, 0.19), and the change in color tone will be significant, so the effect of the present embodiment will be significant. I understand.

In comparison the luminance during black display, black display luminance when not correction execution is 0.87cd / m ^2, in the present embodiment 0.56cd / m ^2, and the reduction of about 35% It becomes possible. This also increases the contrast ratio improvement effect.

  In this example, blue and red light emitting diodes were used as the second colored light sources. The configuration of the liquid crystal panel is the same as that of the fourth embodiment. The arrangement of the light emitting diodes was the same as in Example 4, and the blue / red component ratio was 3: 1. On each side, 6 blue and 2 red are arranged, and the arrangement order is blue, blue, red, blue, blue, red, blue, blue. Also in this case, if the liquid crystal panel size to be used is large, the number may be increased as appropriate.

The first white light source of this example has the spectrum shown in FIG. 12, and the chromaticity coordinates are (0.28,
0.30). The first white light source of the present example has a maximum emission intensity of the green phosphor relatively higher than the maximum emission intensity of red or blue compared to the first white light source used in Example 1. Yes. As a result, the second colored light source is not turned on / off, but the second colored light source is turned on almost constantly and the light control is performed. As a result, there is no significant change in color tone caused by turning on / off, and there is an effect that image quality processing calculation can be facilitated.

  The second coloring light source is independently controlled based on the image signal. To give a simple example, blue is most emphasized in white display, so that only blue is fully lit to obtain the blue-enhanced spectrum shown in FIG. When red is emphasized most at the tip of black display, only red is fully lit, and the spectrum of red enhancement shown in FIG. 12 can be obtained.

  In addition, it is possible to perform light control of blue and red at the same time, and the color of the light source can be controlled as shown in FIG. By controlling the liquid crystal panel and the light source by the image quality processing arithmetic circuit in accordance with the image signal, it is possible to control the optimum color tone in each gradation.

  The present embodiment has the same configuration as that of the first embodiment, and the difference is that a blue fluorescent tube and a red fluorescent tube are arranged on both sides as the second colored light source. In the second coloring light source, blues and reds are controlled simultaneously.

FIG. 14 shows the light emission characteristics of the light source in this example. When the image signal is very low in luminance from black, only red is lit as red enhancement, and the intensity of the first white light source is 0.5, and the chromaticity coordinates are (0.33, 0.31). When the image signal has high luminance, blue is emphasized, blue is fully lit, and red is dimmed (0.24, 0.23). At this time, the light source intensity is the first white light source alone. against 10500cd / m ² when, 12000 cd / m ^2, and the order of about 15% of the brightness enhancement, brightness of the white display can be increased correspondingly. When the average luminance of the input image signal is 190 gradations or more, in FIG. 2, the image quality processing arithmetic circuit 2 corrects the gamma characteristic of the image signal with reference to a look-up table for image control. The image control signal including the corrected image signal and the horizontal / vertical synchronization signal for scanning the liquid crystal panel 10 is supplied to the image control circuit 4, and at the same time, the second coloring is performed with reference to the light source control look-up table. A light source control signal for emphasizing blue of the light source is given to the light source control circuit 3.

When the image signal has a low gradation, red is fully lit and blue is dimmed to (0.29,
It is also possible to control the chromaticity coordinates of 0.26), and the adjustment range according to the image signal can be widened. As described above, according to the image quality processing arithmetic circuit, black as the liquid crystal display device is (0.29, 0.21) and white is (0.26, 0.28). Therefore, a black display that takes the Purkinje phenomenon into consideration can be realized. Also, the chromaticity coordinates of red at the time of low gradation can be (0.53, 0.29), and the achromatic color at the time of low gradation can be (0.28, 0.28). Obtainable.

In this embodiment, as shown in FIG. 15, organic ELs 35 and 36 are used as the second colored light source 30, and the second colored light sources 35 and 36 are arranged immediately below the liquid crystal panel in the same manner as the first white light source 20. did. The number of fluorescent tubes that are the first white light source 20 is an odd number, and an organic EL is disposed between the fluorescent tubes. In this embodiment, since the liquid crystal panel was a 28-inch size, nine fluorescent tubes were used (only five are shown in the figure). In addition, the code | symbol 35 is blue organic EL and the code | symbol 36 is red organic EL. Blue and red are 3: 1, and red is not adjacent to each other when viewed from either the short side or the long side.

The structure of the organic EL is the bottom emission structure shown in FIG. 16, and an ITO thin film is formed as an anode 41 on a clean glass substrate 40. A hole injection layer 42, a hole transport layer 43, a light emitting layer 44, an electron transport layer 45, a lithium fluoride layer 46, and a cathode 47 are formed by sequentially forming a thin film of aluminum and sealed with a sealing tube 48.

  A 2 × 4 square organic EL 4 × 4 matrix element was placed in the backlight case 21. Although it is matcris, it lights up at the same time and does not perform time-division driving. By making it 2 mm square, a margin for foreign matter contamination during manufacturing is secured. The organic EL element was driven at a constant current. Although not shown in the figure, the wiring of the electrodes is directly under the fluorescent tube which is the first white light source. Thus, the diffuse reflection of the first white light source 20 from the inside of the backlight case 21 is not disturbed.

  The spectrum of luminance and color tone control of the light source is shown in FIG. The chromaticity coordinates of the light source were when blue enhancement was maximum (0.25, 0.28) and when red enhancement was maximum (0.33, 0.31). Thereby, it turns out that the effect of this invention is acquired, without being limited to the kind of 2nd coloring light source. The organic EL element structure is not limited to this example. A top emission type is also acceptable. Moreover, application of a multi-photon structure that is optimal as a light source is also mentioned.

In this embodiment, a vertical alignment type liquid crystal panel whose transmission characteristics are shown in FIG. 4 is used. The Δnd of this liquid crystal panel was set to 0.4. FIG. 18 shows spectral characteristics at high luminance and low luminance. The vertical axis represents the intensity of light transmitted through the color filter. It can be seen that the characteristic is blue when the luminance is low and yellowish when the luminance is high. The vertical alignment type liquid crystal panel of this embodiment is a PVA mode liquid crystal panel using slits of transparent electrodes, but may be an MVA mode using protrusions.

  An outline of the configuration of the light source is shown in FIG. The blue fluorescent tube 37 as the second colored light source is a liquid crystal panel so that the number of the first white light sources 20 is 1/2 or 1/2 + 1 so as to be along the first white light sources 20. Place directly below. The red fluorescent tube 38 as the second coloring light source is a light guide plate type. Although the inverter is not shown, the inverters are connected in blue and red. Thereby, blue emphasis can be obtained more remarkably.

FIG. 20 shows the blue enhancement and red enhancement of the light source and the spectrum of the first white light source. The chromaticity coordinates of the first white light source are (0.26, 0.23), and (0.21, 0.16) when blue enhancement is maximum. Usually, there is a side effect that the efficiency decreases and the luminance decreases when the color temperature is increased with only one type of fluorescent tube. However, in this embodiment, the luminance of the first white light source alone is 11000 cd / m. ^In contrast to the maximum luminance of 13,800 cd / m ² can be obtained at the maximum luminance, and an increase of about 25% can be expected. It can be seen that a high color temperature and high brightness can be realized with a light source. Further, when the red enhancement is maximum, the chromaticity coordinates (0.32, 0.25).

  Accordingly, white display is possible in the vertical alignment type liquid crystal panel using the driving voltage indicating the maximum transmittance of the liquid crystal layer. That is, in this embodiment, the chromaticity coordinates of white can be (0.28, 0.31) even in the spectral characteristics shown in FIG. If the second colored light source is not used as in the present embodiment, the chromaticity coordinates are (0.35, 0.38), and yellow rather than white is no longer visible. For low-brightness red, (0.60, 0.29) can be realized. In black, (0.24, 0.16). If correction by the second red coloring light source is not performed, black is (0.19, 0.14), and it can be seen that it can be greatly improved.

  In this embodiment, the second colored light source is used as a fluorescent tube, but it is of course possible to replace it with a light emitting diode. Using a light emitting diode is more effective because both the blue and red color purity are high.

  In this embodiment, a liquid crystal panel having a structure in which the pixels of the liquid crystal panel are composed of red, green, blue, and white sub-pixels is used. The pixels are divided into four equal squares, and the upper stage 2 and the lower stage 2 have the structure. The liquid crystal display mode is a horizontal electric field type liquid crystal panel that uses a fringe electric field, and a liquid crystal panel in which Δnd is set to 0.4 μm is used. FIG. 21 shows spectral characteristics provided with a color filter. Note that the transmittance of black to low luminance display is enlarged 10 times.

  As the light source, the second colored light source 30 shown in FIG. In the second coloring light source 30, two blue fluorescent tubes are arranged on each side of the light guide plate 32. The liquid crystal panel used in the present embodiment can use only blue as the second colored light source 30 because the color shift to blue in black display is suppressed due to the effect of the white subpixel without a color filter.

When the average luminance of the image signal is 140 gradations or more, or when the maximum luminance is 200 gradations or more, the blue fluorescent tube as the second coloring light source 30 is turned on and the processing calculation is performed. The chromaticity coordinates of the first white light source 20 are (0.29, 0.26). The chromaticity coordinates in the case of blue enhancement are (0.26, 0.21). While the maximum luminance of the first white light source alone is 10500 cd / m ² , the light source luminance in the case of blue enhancement is 11500 cd / m ² , which is increased by about 10%.

  The spectrum of the light source of this example is shown in FIG. The white display in this embodiment is (0.29, 0.26) using blue enhancement, and black suppresses the intensity of the first white light source 20 to about ½, and (0.25, 0). .21).

  In this embodiment, the color temperature is set to be high. However, when the color temperature of the liquid crystal television is to be lowered, the first white light source 20 is changed to one having a low color temperature, or the second color light source. It may be controlled so that 30 is weakened.

  Further, there is no problem in the image quality even if the blue light source is turned on by judging with the maximum luminance of the image signal for the following reason. The visual perception of the human eye always sees a relative contrast ratio and is said to be approximately 200: 1. Therefore, if there is an image portion with a high luminance, the perception of black is dull. Therefore, in this embodiment, even when the blue light source is turned on when the maximum luminance is 200 gradations or more, the coloring of the dark image portion is Almost not recognized. Therefore, the effect can be obtained even when only blue is used as the second coloring light source 30.

  Furthermore, it can be seen from the previous embodiment that the use of red as the second colored light source 30 increases the effect. In particular, when controlling the brightness of the surrounding environment, it is very effective when considering the Purkinje phenomenon.

  In addition, when the liquid crystal panel has white subpixels, the image quality processing arithmetic circuit can optimize the image signal given to the white subpixels for the purpose of color purity correction. In this embodiment, a fluorescent tube is used as the second colored light source 30, but there is no problem as a light emitting diode. Further, the second colored light source 30 may be a light guide plate or may be arranged side by side with the first white light source 20. When a higher brightness light source is required, it is effective to line up with the first white light source 20.

  The light source provided on the back surface of the liquid crystal panel of Example 10 shown in FIG. 23 is a white light emitting diode 50 as a first white light source disposed immediately below the liquid crystal panel, and red and blue light emitting diodes as second colored light sources. 51 is used.

  The white light emitting diode 50 is accommodated in the elongated backlight case 21. The arrangement was green, blue, green, green, red, blue, green, green, red, blue, green, green, red, blue, green, green, red, green. In other words, with a configuration in which four light emitting diodes of blue, green, green and red are arranged in series as one repeating unit, four repeating units are arranged in series, and one green light emitting diode is arranged on each side. The configuration is one unit. The second colored light source 51 was disposed between the first white light sources 50. The liquid crystal panel was a vertical alignment type liquid crystal panel, and the image quality processing calculation was almost the same as in Example 8. However, the dimming of the first white light source was performed not by current control but by time division modulation.

  The light source provided on the back surface of the liquid crystal panel of Example 11 shown in FIG. 24 is a white light emitting diode 50 as a first white light source disposed immediately below the liquid crystal panel, and red and blue light emitting diodes as second colored light sources. 51 is used.

  The white light emitting diode 50 is accommodated in the elongated backlight case 21. The arrangement was green, blue, green, green, red, blue, green, green, red, blue, green, green, red, blue, green, green, red, green. That is, a configuration in which four light emitting diodes of blue, green, green and red are arranged in series is regarded as one repeating unit, four repeating units are arranged in series, and one green light emitting diode is arranged on each side. The configuration is one unit. The arrangement configuration of the light emitting diodes as the second colored light source is the same as that of Example 4, and the configuration ratio of blue and red is 3: 1. On both sides, 6 blue and 2 red are arranged, respectively, in the order of blue, blue, red, blue, blue, red, blue, blue. The image quality processing calculation is almost in accordance with the fifth embodiment. The dimming of the first white light source is based on pulse width modulation.

  In the present embodiment, a light source unit is used in which both the first and second light sources are arranged immediately below the liquid crystal panel 10 and a diffusion plate is arranged so that both lights are mixed. The schematic diagram of the light source unit of the present embodiment is configured such that both the second light sources 35 and 36 are red light emitting diodes in FIG. The configuration is the same as that of Example 4 except that the arrangement of the second light source and the color temperature of the first light source are higher, that is, the chromaticity coordinates are (0.22, 0.24).

FIG. 26 shows emission spectra of the first light source and the second light source in this example. The chromaticity coordinates of the second light source are (0.70, 0.30). When the intensity of the second light source is controlled without changing the first light source intensity, the chromaticity coordinates as the light source incident on the liquid crystal panel are from (0.22, 0.24) to (0.26, 0.20). 25). The former is a case where only the first light source is turned on, and the latter is a case where the second red light source is fully lit. In this embodiment, the present invention is applied when the luminance level of the input image signal is higher than 88 gradations. . On the other hand, when the first light source intensity is reduced to ½, it is changed between (0.30, 0.25) and (0.22, 0.24) by the second light source intensity control. It is possible. The former is when the second light source is fully lit, and the latter is when only the first light source is lit. The light source can be controlled in the meantime, but when the light source luminance is reduced, in this embodiment, the range of chromaticity coordinates from (0.30, 0.25) to (0.26, 0.25). Applied in. Although applied when the luminance level of the input image signal is 88 gradations, the second light source is fully lit within this range because the signal of 31 gradations or less is 70% or more and the maximum luminance in the image signal Was 62 gradations or less. Note that the reference gradation is not limited to the present embodiment, and is appropriately optimized based on the design guidelines such as emphasizing the characteristics of the liquid crystal panel to be used, preferable color reproducibility, or faithful color reproducibility. You just have to.

In the liquid crystal panel used in this embodiment, the chromaticity coordinates for the standard light source C for all pixel display, that is, white display are (0.32, 0.36), and the chromaticity coordinates for the standard light source C for black display are (0.26). , 0.31). When the color tone correction by the light source is not performed, the chromaticity coordinates for white display are (0.28, 0.29), whereas the chromaticity coordinates for black display are greatly changed to (0.23, 0.22). To do. By adopting the configuration of this embodiment, it is possible to correct a change in color tone between black and white gradations with a light source, and (0.28, 0.29) for white display and (0.27, 0) for black display. .240). In the configuration of the present embodiment, the second red light source is fully lit in black display, but the increase in the luminance of the black display of the liquid crystal display device is very small, and the black display is achieved by reducing the luminance of the first light source. The effect of improving the contrast ratio by reducing the brightness is sufficiently retained. The brightness of the black display in this embodiment is 0.33 cd / m ² , and it is 0.3 when the tone correction is not performed, that is, when the brightness of the second light source is reduced to ½ like the first light source. It is 31 cd / m ² , indicating that there is no problem. Since the luminance of black display when the light source luminance is the same as that during white display is 0.61 cd / m ² , the effect of reducing the luminance of black display is sufficiently obtained. Further, in order to improve the contrast ratio, there is a sufficient effect only by the control for reducing the luminance without performing the color tone correction.

  Further, a configuration in which the ambient light detection circuit is provided and the light source control is performed in the same manner even when the ambient brightness is a dark environment of 50 lux or less is possible. In this case, the luminance may be controlled to be halved in the same manner as the first light source without depending on the image signal and without performing the color tone control by the second light source.

  In this embodiment, in order to set the color temperature of the first light source high, the light source is composed of only blue and green phosphors. With this configuration, it is possible to control the high luminance display only with the second red light source, and the control can be easily performed. Since the green phosphor has secondary light emission in the vicinity of 588 nm and 620 nm as shown by the thin line in FIG. 26, it can be used as a first light source having a high color temperature without using a red phosphor. In addition, the narrow-band phosphor type phosphor is preferable from the viewpoint of luminance efficiency because the luminous efficiency of blue and green is good. Furthermore, although the red light emitting diode is used as the second light source, since the efficiency of red is high in the light emitting diode, the configuration of this embodiment is a combination of those having high efficiency. This is a very preferable configuration. Further, in the configuration of the present embodiment, the main light source for displaying red depends on the light emitting diode of the second light source, so that the effect of improving the color purity of red display is high, which is a more preferable configuration in terms of improving the image quality.

  In the present embodiment, a light source unit using two diffuser plates is used so that both the first and second light sources are arranged immediately below the liquid crystal panel 10 and the light of both is mixed. A schematic diagram of the light source unit of this embodiment is shown in FIG. The emission spectra of the first light source and the second light source in this example are the same as those in Example 12.

  In the present embodiment, as shown in FIG. 27, the first light source is arranged so that light having a stronger intensity is incident on the central portion of the liquid crystal panel. Using this, the light source intensity optimized by the image signal of the television is controlled. For example, among 256 gradation (0 to 255 gradation) displays, 225 gradation is used as a normal white display, and the peak luminance is set for an image input signal of a television set from 226 to 255 gradation as a peak luminance display. In the case of a display that requires a light source, control is performed to increase the first light source intensity. As a result, the first light source performs three-level luminance control from 255 gradations to 226 gradations, 225 gradations to 88 gradations, and 88 gradations to 0 gradations. In order to prevent light source luminance reduction from 225 gradations to 88 gradations, the number of first light sources was increased from 12 to 16. At this time, considering that the demand for high luminance is biased toward the center of the liquid crystal panel as viewed from the observer, the added light source is arranged at the center of the liquid crystal panel. In addition, a red light emitting diode is arranged at the center so that the intensity of the second light source is slightly higher according to the luminance. Note that the second red light source luminance may or may not be controlled when the first light source luminance is increased during peak luminance display. Even if the second red light source luminance is not increased, sufficient luminance can be obtained only by increasing the first light source luminance, and when displaying a high luminance such as a peak luminance, a bluish color This is because a display with a higher temperature uses a psychological visual effect that looks more effective. Since the first light source of the present embodiment is composed of blue and green phosphors, the intensity increase of the first light source can be set as a blue-enhanced light source setting. In this embodiment, the color temperature of the light source is increased only by increasing the first light source intensity without increasing or decreasing the second red light source intensity. If a higher light source luminance is required, it is of course possible to use a control signal for increasing the second light source luminance. Further, it may be controlled so as to increase the luminance of the first light source in a bright environment having a peripheral brightness detection circuit and having a periphery of 400 lux or more.

In this embodiment, the maximum luminance of the light source is 11700 cd / m ² (luminance as the light source unit through the diffusion plate), and the chromaticity coordinates at this time are (0.255, 0.24), and the liquid crystal display A high luminance of 600 cd / m ² can be displayed as the peak luminance in the apparatus. At this time, the chromaticity coordinate of the peak white display in the liquid crystal display device was (0.275, 0.295). The light source luminance and chromaticity coordinates from normal white display to 88 gradations are 9900 cd / m ² (0.26, 0.245), and 512 cd / m ² , (0 .283, 0.297). The light source luminance and chromaticity coordinates in black display are 5500 cd / m ² ,
(0.30, 0.25), and in the black display of the liquid crystal display device, 0.33 cd / m ² ,
(0.27, 0.23). The emission spectrum of the light source under the above control conditions is shown in FIG. In this embodiment, the peak luminance can be displayed, and the image quality improvement effect is remarkable. The red chromaticity coordinates are (0.66, 0.30). Since the chromaticity coordinates of red in the comparative example are (0.64, 0.32), it can be seen that the effect of improving the color purity is great. Further, when the green display and the blue display were compared, the green color in this example was (0.28, 0.62) and the blue color was (0.14, 0.07). In both cases, the green color of the comparative example is (0.29, 0.61) and the blue color is (0.14, 0.078), but the color purity is also improved.

1 is a basic configuration diagram of a liquid crystal display device according to the present invention. 1 is a circuit configuration diagram of a liquid crystal display device according to the present invention. The other circuit block diagram of the liquid crystal display device which concerns on this invention. FIG. 6 is a relationship diagram between an applied voltage and brightness of each pixel in a vertical alignment mode liquid crystal panel. FIG. 6 is a spectral characteristic diagram of black to low luminance display and high luminance display of a horizontal electric field type liquid crystal panel. Human visual sensitivity characteristic diagram. FIG. 3 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 1. FIG. 10 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 2. FIG. 7 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 3. The other block diagram of the light source in this invention. FIG. 10 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 4; FIG. 9 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 5. FIG. 10 is a diagram showing the effect of color tone control of a light source in Example 5. FIG. 10 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 6. The other block diagram of the light source in this invention. The block diagram of the organic EL element used as a 2nd coloring light source in this invention. FIG. 10 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 7. The spectral characteristic figure of a vertical alignment type liquid crystal panel. The other block diagram of the light source in this invention. FIG. 11 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 8. The spectral characteristic figure of the liquid crystal panel provided with the color filter. 10 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 9. FIG. The other block diagram of the light source in this invention. The other block diagram of the light source in this invention. The figure which shows the colorimetric range and the chromaticity coordinate of white and black display in the conventional liquid crystal display device. The figure which shows the light emission characteristic of the 1st, 2nd light source in Example 12 and 13. FIG. Schematic which shows the light source unit structure of Example 13. FIG. FIG. 14 is a light emission characteristic diagram of a spectral intensity ratio for color tone control of a light source in Example 13.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Brightness detection circuit, 2 ... Image quality processing arithmetic circuit, 3 ... Light source control circuit, 4 ... Image control circuit, 5 ... Ambient environment brightness detection circuit, 10 ... Liquid crystal display panel, 20 ... 1st white light source, 21 ... Backlight case, 30 ... second colored light source, 31 ... light source storage unit, 32 ... light guide plate,
33 ... Diffusion plate, 35 ... Blue organic EL element, 36 ... Red organic EL element, 37 ... Blue second colored light source, 38 ... Red second colored light source, 40 ... Glass substrate, 41 ... Anode, 42 ... hole injection layer, 43 ... hole transport layer, 44 ... light emitting layer, 45 ... electron transport layer, 46 ... lithium fluoride layer, 47 ... cathode, 48 ... sealed tube, 50 ... white light emitting diode, 51 ... Colored light emitting diode.

Claims (26)

In a liquid crystal display device comprising a first white light source and a second colored light source for irradiating light to a liquid crystal panel for displaying an image,
To control the light source control signal for controlling the intensity of the second colored light source and the image displayed on the liquid crystal panel based on the detection result from the detection circuit for detecting the brightness of the input image signal An image quality processing arithmetic circuit for outputting the image control signal is provided. In a liquid crystal display device comprising a first white light source and a second colored light source for irradiating light to a liquid crystal panel for displaying an image,
A light source control signal for independently controlling the intensity of the first white light source and the intensity of the second colored light source based on a detection result from a detection circuit for detecting the brightness of the input image signal; A liquid crystal display device comprising an image quality processing arithmetic circuit for outputting an image control signal for controlling an image displayed on a liquid crystal panel. In a liquid crystal display device comprising a first white light source and a second colored light source for irradiating light to a liquid crystal panel for displaying an image,
Based on the detection result from the detection circuit that detects the brightness of the input image signal and the detection result from the detection circuit that detects the brightness around the liquid crystal panel, the intensity of the first white light source and the An image quality processing arithmetic circuit for outputting a light source control signal for independently controlling the intensity of the two colored light sources and an image control signal for controlling an image displayed on the liquid crystal panel is provided. Liquid crystal display device. The first white light source is a cold cathode fluorescent tube using a narrow-band phosphor type phosphor,
The second colored light source is a red light source;
The image quality processing arithmetic circuit controls the intensity of the red light source when it is detected that the average luminance of the input image signal is lower than the predetermined luminance and the maximum luminance is lower than the predetermined luminance. The liquid crystal display device according to claim 1, wherein a light source control signal for controlling the image and an image control signal for controlling an image displayed on the liquid crystal panel are output. The first white light source is a cold cathode fluorescent tube using a narrow-band phosphor type phosphor,
The second colored light source is a blue light source;
The image quality processing arithmetic circuit is displayed on the liquid crystal panel and a light source control signal for controlling the intensity of the blue light source when it is detected that the average luminance of the input image signal is higher than a predetermined luminance. 2. The liquid crystal display device according to claim 1, wherein an image control signal for controlling an image to be output is output. The first white light source is a cold cathode fluorescent tube using a narrow-band phosphor type phosphor,
The second coloring light source comprises a red light source and a blue light source,
The image quality processing arithmetic circuit determines the intensity of the first white light source when it is detected that the average luminance of the input image signal is lower than the predetermined luminance and the maximum luminance is lower than the predetermined luminance. A light source control signal for controlling the intensity of the red light source and an image control signal for controlling an image displayed on the liquid crystal panel, and the average luminance of the input image signal is Outputting a light source control signal for controlling the intensity of the blue light source and an image control signal for controlling an image displayed on the liquid crystal panel when it is detected that the luminance is higher than a predetermined luminance. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is a liquid crystal display device. The first white light source is a cold cathode fluorescent tube using a narrow-band phosphor type phosphor,
The second coloring light source comprises a red light source and a blue light source,
The image quality processing arithmetic circuit reduces the intensity of the first light source when it is detected that the average luminance of the input image signal is lower than the predetermined luminance and the maximum luminance is lower than the predetermined luminance. A light source control signal for increasing the intensity of the red light source and an image control signal for controlling an image displayed on the liquid crystal panel, and an average luminance of the input image signal is determined. Output a light source control signal for increasing the intensity of the blue light source and an image control signal for controlling an image displayed on the liquid crystal panel when it is detected that the brightness is higher than the brightness. The liquid crystal display device according to claim 2 or 3. The first white light source is a cold cathode fluorescent tube using a narrow-band phosphor type phosphor,
The second colored light source is disposed on at least one side of a light guide plate disposed on the back side of the liquid crystal panel,
The light guide plate transmits light from the first white light source, uniformizes light from the second colored light source, and irradiates the back surface of the liquid crystal panel. A liquid crystal display device according to any one of the above. The first white light source is a narrow-band phosphor type fluorescent tube,
8. The diffuser plate that mixes light from the first white light source and light from the second colored light source is disposed on the back surface of the liquid crystal panel. Liquid crystal display device. The first white light source is a narrow-band phosphor type fluorescent tube,
The second colored light source is disposed on at least one side of a light guide plate disposed on the back side of the liquid crystal panel, and includes a plurality of different types of light emitters.
9. The liquid crystal display device according to claim 1, wherein at least one kind of the light emitters is disposed on the light guide plate.   11. The liquid crystal display device according to claim 8, wherein at least one of the second colored light sources is a narrow-band light-emitting fluorescent tube.   The liquid crystal display device according to claim 8, wherein at least one of the second colored light sources is an organic electroluminescence element.   The liquid crystal display device according to claim 8, wherein at least one of the second light sources is a light emitting diode.   4. The liquid crystal display device according to claim 1, wherein the liquid crystal panel is a normally closed liquid crystal display type.   4. The liquid crystal display device according to claim 1, wherein the liquid crystal panel is a vertically closed normally closed type.   The pixel unit of the liquid crystal panel is composed of red, blue, and green sub-pixels in which red, blue, and green color filters are arranged, and a white sub-pixel that displays only transmitted light intensity. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a liquid crystal display device. The first white light source is a light emitting diode;
The second colored light source is a red light emitting diode;
The image quality processing arithmetic circuit controls the intensity of the red light emitting diode when it is detected that the average luminance of the input image signal is lower than the predetermined luminance and the maximum luminance is lower than the predetermined luminance. The liquid crystal display device according to claim 1, wherein a light source control signal for controlling and an image control signal for controlling an image displayed on the liquid crystal panel are output. The first white light source is a light emitting diode;
The second colored light source is a blue light emitting diode;
The image quality processing arithmetic circuit is displayed on the liquid crystal panel and a light source control signal for controlling the intensity of the blue light source when it is detected that the average luminance of the input image signal is higher than a predetermined luminance. 2. The liquid crystal display device according to claim 1, wherein an image control signal for controlling an image to be output is output. The first white light source is a light emitting diode;
The second colored light source comprises a red light emitting diode and a blue light emitting diode,
The image quality processing arithmetic circuit determines the intensity of the first white light source when it is detected that the average luminance of the input image signal is lower than the predetermined luminance and the maximum luminance is lower than the predetermined luminance. A light source control signal for controlling the intensity of the red light emitting diode and an image control signal for controlling an image displayed on the liquid crystal panel, and an average luminance of the input image signal Is detected to be higher than a predetermined luminance, a light source control signal for controlling the intensity of the blue light emitting diode and an image control signal for controlling an image displayed on the liquid crystal panel are output. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is a liquid crystal display device. The first white light source is a light emitting diode;
The second colored light source comprises a red light emitting diode and a blue light emitting diode,
The image quality processing arithmetic circuit reduces the intensity of the first light source when it is detected that the average luminance of the input image signal is lower than the predetermined luminance and the maximum luminance is lower than the predetermined luminance. A light source control signal for increasing the intensity of the red light emitting diode and an image control signal for controlling an image displayed on the liquid crystal panel, and the average luminance of the input image signal is When it is detected that the luminance is higher than a predetermined luminance, a light source control signal for increasing the intensity of the blue light emitting diode and an image control signal for controlling an image displayed on the liquid crystal panel are output. The liquid crystal display device according to claim 2, wherein: A first light source for irradiating light to a liquid crystal panel for displaying an image and a second red light source;
A light source control signal and the liquid crystal for independently controlling the intensity of the first light source and the intensity of the second red light source based on a detection result from a detection circuit that detects the brightness of the input image signal. In a liquid crystal display device provided with an image quality processing arithmetic circuit that outputs an image control signal for controlling an image displayed on a panel,
The image quality processing arithmetic circuit reduces the intensity of the first light source when it is detected that the average luminance of the input image signal is lower than the predetermined luminance and the maximum luminance is lower than the predetermined luminance. And outputting a light source control signal for controlling the intensity of the second red light source independently of the first light source and an image control signal for controlling an image displayed on the liquid crystal panel. A characteristic liquid crystal display device. A first light source that irradiates light onto a liquid crystal panel that displays an image and a second red light source, and based on a detection result from a detection circuit that detects the brightness of an input image signal, the first light source An image quality processing arithmetic circuit for outputting a light source control signal for independently controlling the intensity of the light source and the intensity of the second red light source and an image control signal for controlling an image displayed on the liquid crystal panel is provided. In liquid crystal display devices,
The image quality processing arithmetic circuit is a light source for controlling the second red light source intensity independently from the first light source when it is detected that the average luminance of the input image signal is higher than a predetermined luminance. A liquid crystal display device that outputs a control signal and an image control signal for controlling an image displayed on the liquid crystal panel.   A light source control signal for independently controlling the intensity of the first light source and the intensity of the second red light source on the basis of a detection result of a detection circuit for detecting brightness around the liquid crystal panel; 23. The liquid crystal display device according to claim 21, further comprising an image quality processing arithmetic circuit that outputs an image control signal for controlling an image to be displayed.   The said 1st light source is a fluorescent tube mainly consisting of blue and green narrow-band light-emitting type | mold fluorescent substance, Comprising: The said 2nd light source is a red light emitting diode, The Claim 21 and 22 characterized by the above-mentioned. Liquid crystal display device.   25. The liquid crystal display device according to claim 24, wherein a diffusion unit that mixes the light from the first light source and the light from the second red light source is disposed on the back surface of the liquid crystal panel. The second red light source is disposed on at least one side of a light guide plate disposed on the back side of the liquid crystal panel,
The light guide plate transmits light from the first light source, uniformizes light from the second red light source, and irradiates the back surface of the liquid crystal panel. Liquid crystal display device.

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