WO2010150299A1 - Liquid crystal display device - Google Patents

Abstract

A liquid crystal display device obtains first intensities of light sources, based on a backlight having a plurality of color light sources which respectively emit light of different colors and on maximum values of input image signals for respective color components corresponding to the light source colors.  A second calculating section obtains second intensities of the light sources, based on the average values of the input image signals for the color components which correspond to the light source colors.  A third calculating section calculates a gain for each color component, based on the ratio between the first intensity and the second intensity.  A third intensity of the light source is calculated by multiplying the maximum value of the input image signals by the gain for each color component.

Description

Liquid crystal display

The present invention relates to a liquid crystal display device including a backlight having a plurality of color light sources.

In a liquid crystal display device, research is being conducted on a technique for controlling the intensity of light emitted from a backlight in accordance with a video signal for the purpose of improving the contrast of the displayed video and reducing power consumption. In recent years, research has been conducted on technologies for controlling backlights using color LEDs as well as conventional white LEDs.

There is a technique for obtaining a histogram of video signal values for each color component of an input video and setting the light emission intensity of each color light source from the center of gravity of the histogram (for example, Patent Document 1). In this method, if the input video contains a pixel area that is significantly different in chromaticity from the calculated light of each color light source, the gradation value that controls the liquid crystal transmittance exceeds the value that can be displayed on the liquid crystal panel, and the area Color misregistration may occur. In addition, there is a method of correcting the transmittance of the liquid crystal while maintaining the chromaticity of the input video, but the brightness of the displayed video has been greatly reduced in order to maintain the chromaticity.

JP 2006-292914 A

In the above-described conventional technology, there is a problem that the video cannot be displayed in accordance with the input video, and the color is shifted between the input video and the displayed video.

The present invention has been made in view of the above problems, and an object of the present invention is to display an image in which color misregistration is suppressed without significantly reducing the brightness of the image to be displayed.

In order to solve the above-described problems, the present invention provides a backlight in which a plurality of light sources each having a color light source that emits light of different colors and a video display area by modulating the light from the backlight. Based on the maximum value of the input video signal in the illumination area obtained by virtually dividing the display area based on the spatial arrangement of the light source for each color component corresponding to the color light source and the liquid crystal panel to be displayed in A first calculation unit that obtains a first intensity of the color light source, and a first value of the color light source based on an average value of the input video signal in the illumination area for each color component corresponding to the color light source. A second calculation unit for obtaining an intensity of 2, a maximum value of the first intensity or a value indicating brightness of the first intensity, a maximum value of the second intensity, or the second intensity Gay from the ratio of the brightness value The color light source according to the light source intensity, a light source intensity calculation unit for calculating a light source intensity from a third intensity of the color light source obtained by multiplying the first intensity by the gain, An estimation unit that estimates a distribution of light emitted from the backlight when emitting light, a correction unit that obtains a corrected video signal obtained by correcting the input video signal based on the distribution, and a light source that controls the light source according to the light source intensity There is provided a liquid crystal display device comprising: a control unit; and a panel control unit that controls the liquid crystal panel according to the corrected video signal.

According to the present invention, it is possible to display an input image and an image with little color shift without greatly reducing luminance.

The figure which shows the liquid crystal display device of 1st Embodiment. The figure which shows the light source intensity | strength calculation part of 1st Embodiment. FIG. 3 is a diagram showing a backlight according to the first embodiment. The figure which shows the processing flow of the liquid crystal display device of 1st Embodiment. The figure which shows the example of the image | video which a color shift generate | occur | produces. The figure which shows the example of the setting method of the light source intensity | strength of each color. The figure which shows the example of the image | video which a color shift generate | occur | produces. The figure which shows the example of the setting method of the light source intensity | strength of each color. FIG. 5 is a diagram showing a liquid crystal display device of a second embodiment.

Hereinafter, embodiments of the present invention will be described. In addition, the same code | symbol is attached | subjected to the structure and process which mutually perform the same operation | movement, and the overlapping description is abbreviate | omitted.

[First embodiment]
FIG. 1 is a diagram showing a liquid crystal display device 100 of the present embodiment.

The liquid crystal display device 100 includes a conversion unit 109, a calculation unit 105, a calculation unit 106, a light source intensity calculation unit 107, a light source control unit 102 that controls the backlight 101, and a backlight 101 including a plurality of color light sources. A signal correction unit 108, a panel control unit 104 that drives and controls the liquid crystal panel 103, and a liquid crystal panel 103 that modulates the transmittance or reflectance of light from the backlight 101. In the present embodiment, the backlight 101 has light sources of light emitting diodes (LEDs) of R (red), G (green), and B (blue), and controls the light intensity for each color in a batch. Examples are described below.

The conversion unit 109 obtains an input video signal 111 by subjecting the input video signal 110 to format conversion to RGB and gamma conversion. If the input video signal 110 is already in the RGB format, the conversion is omitted.

The calculation unit 105 calculates the maximum value (hereinafter referred to as each color component) in each of the R, G, and B signal values of the input video signal 111. Based on the obtained maximum value, the intensity value 112 of each color light source included in the backlight 101 is calculated.

The calculation unit 106 calculates an average value for each color component of the input video signal 111. Based on the obtained average value, the intensity value 113 of each color light source of the backlight 101 is calculated.

The light source intensity calculation unit 107 calculates the light source intensity 114 from the intensity value 112 and the intensity value 113. The light source luminance 114 is calculated by multiplying the intensity value 112 by a gain obtained from the ratio between the maximum values of the intensity value 112 and the intensity value 113. Details of the calculation method will be described later.

The signal correction unit 108 obtains a corrected video signal 115 obtained by correcting the input video signal 111 according to the light source intensity 114 in order to correct the transmittance of the liquid crystal.

FIG. 2 is a diagram showing details of the light source intensity calculation unit 107.

The light source intensity calculation unit 107 includes a gain calculation unit 122 that calculates a ratio (hereinafter, referred to as gain) 127 of the maximum value of the intensity value 112 and the maximum value of the intensity value 113, the intensity value 112, the intensity value 113, and the gain. And an intensity calculation unit 123 that calculates the light source intensity 114 from 127.

FIG. 3 is a diagram showing the details of the backlight 101. The light source 130 of the backlight 101 includes an R light source 131, a G light source 132, and a B light source 133, which are three color light sources. Each color light source can control its emission intensity. In the present embodiment, an example in which color light sources of the same color are controlled to emit light with the same intensity regardless of the position will be described. It is assumed that the intensity of light incident on the liquid crystal panel is constant regardless of the position. FIG. 3 shows an example of the configuration of the backlight, and other configurations may be used.

Next, details of the operation of the liquid crystal display device 100 of the present embodiment will be described.
FIG. 4 is a flowchart showing the operation of the liquid crystal display device 100 of the present embodiment.
First, the conversion unit 109 converts the signal of each pixel of the input video signal 110 into an RGB format signal. Thereafter, the gamma conversion of Expression (1) is performed on the gradation value S _in for each color component of each pixel to convert it into L _in .

Γ represents the gamma coefficient. Alternatively, a gamma conversion calculation may be performed by preparing a lookup table in which a gradation value input in advance and a gradation value after gamma conversion are associated with each other. The above conversion is performed on the R, G, and B values of all the pixels of the input video signal 110 to obtain the input video signal 111 that has been gamma-converted (S401).

Next, the calculation unit 105 calculates the maximum value (R _max , G _max , B _max ) for each color component from the pixel values of all the pixels in the image of the input video signal 111. The determined maximum values (R _max , G _max , B _max ) are set as the light source intensity values 112 (R _max , G _max , B _max ) (S402). Note that the maximum value of all the pixels of the video signal smoothed by applying a low-pass filter to the input video signal 111 may be used as the intensity value 112.

Next, the calculation unit 106 calculates the intensity value 113 (R ′ _ave , G ′ _ave , B ′ _ave ) from the average value (R _ave , G _ave , B _ave ) for each color component of the input video signal 111. (S403). The average value is the average value of all the pixels of the input video signal 111, the center of gravity of the histogram of all the pixels of the input video signal 111, the mode value of all the pixels of the input video signal 111, and all the pixels of the input video signal 111. Either the maximum value or the median value of the minimum values may be used. An intensity value 113 (R ′ _ave , G ′ _ave , B ′ _ave ) is calculated by multiplying an average value (R _ave , G _ave , B _ave ) for each color component by a correction coefficient α.
_R'ave = α x _Rave , _G'ave = α x _Gave , _B'ave = α x _Bave (2)
The correction coefficient α is preferably a half value of the dynamic range of the liquid crystal panel 103, but may be other values.

Next, the gain calculation unit 122 _selects the maximum value L _max among the intensity values 112 (R _max , G _max , B _max ) and the intensity value 113 (R ′ _ave , G ′ _ave , B ′ _ave ). The size of the value L _ave that is the largest at is compared (S404). The three values R _max , G _max , and B _max are compared with each other, and the largest value is taken as L _max . For example, if R _max> G _max> B _max , L _max = R _max . In the present embodiment, the _{L max (R max, G max} , B max) was the maximum value of the Y when converting _{(R max, G max, B} max) of the YUV space L it may be used as the _{max, (R max, G max} , B max) L may be the L _max when was converted to L * a * b space. The same applies to _Lave . _{That, (R max, G max,} B max) and _{(R ave, G ave, B} ave) may determine the L _max based on the value indicating the brightness component of the.

When L _max is larger than L _ave (S404, Yes), the gain calculation unit 122 calculates the gain 127 from the equation (3) (S405). G, which is a gain 127, is a ratio between L _max and L _ave .

Next, as shown in the equation (4), the intensity calculator 123 corrects the intensity value 112 (R _max , G _max , B _max ) by the gain 127 (R ′ _max , G ′ _max , B 'the _max) was calculated from the equation (4), correction intensity value (R' _max, G _'max, B' _max) is the intensity value 113 (R _'ave, G' _ave, whether greater than B _'ave) Is determined for each color component (S406).
R ′ _max = G × R _max , G ′ _max = G × G _max , B ′ _max = G × B _max (4)
When the corrected intensity value is larger than the intensity value 113 (S406, Yes), the corrected intensity value is set to the light source intensity 114 of each RGB color (S407).

When R ' _ave ≤ R' _max R _BL = R ' _max
G _BL = G _'max when the G' _ave ≦ G _'max
When B ' _ave ≤ B' _max B _BL = B ' _max
Note that (R _BL , G _BL , B _BL ) respectively indicate the light source intensity 114 for each color component.

When the intensity value 113 is larger than the corrected intensity value (S406, No), the intensity value 113 is set to the light source intensity 114 (S408).

When R ′ _ave > R ′ _max , R _BL = R ′ _ave
When G ′ _ave > G ′ _max , G _BL = G ′ _ave
When B ' _ave >B' _max B _BL = B ' _ave
In step S404, if L _max is smaller than L _ave (S203, No), the intensity value 112 is set to the light source intensity 114 (S409).

_RBL = _Rmax , _GBL = _Gmax , _BBL = _Bmax (5)
The light source intensity calculation unit 107 sends the calculated light source intensity 114 to the signal correction unit 108 and the light source control unit 102.

Next, the signal correction unit 108 obtains a corrected video signal 115 obtained by correcting the input video signal 111 in accordance with the light source intensity 114 in order to correct the transmittance (S410). The RGB values of the pixel at the position (x, y) in the input video signal 111 are R _in (x, y), G _in (x, y), and B _in (x, y), respectively. In general, RGB values D _R (x, y), D _G (x, y), and D _B (x, y) displayed on the liquid crystal panel 103 are values R _BL (x, y) of the light source intensity 114. , G _BL (x, y), B _BL (x, y), transmittance T _R (x, y), T _G (x, y), T _B (x , y) is expressed as in equation (6).

However, the coefficients k11 to k33 maximize the transmittance of each color component of the liquid crystal panel 103 under the light source intensities R _BL (x, y), G _BL (x, y), and B _BL (x, y). When
k11: intensity of R component light transmitted through the sub-pixel R.
k12: intensity of R component light transmitted through the sub-pixel G.
k13: intensity of R component light transmitted through the subpixel B.
k21: Intensity of G component light transmitted through the subpixel R.
k22: G component light intensity transmitted through the sub-pixel G.
k23: G component light intensity transmitted through the sub-pixel B.
k31: Intensity of B component light transmitted through the subpixel R.
k32: the intensity of the B component light transmitted through the subpixel G.
k33: Intensity of the B component light transmitted through the subpixel B.
Represents.

(D _R (x, y), D _G (x, y), D _B (x, y)) = (R _in (x, y), G _in (x, y), B _in (x, y) ). Therefore, the corrected transmittance of the liquid crystal panel 103 for displaying (R _in (x, y), G _in (x, y), B _in (x, y)) is set to (R _TR (x, y), G _TR (x, y), B _TR (x, y)), (R _in (x, y), G _in (x, y), B _in (x, y)) and (R _TR (x , y), G _TR (x, y), B _TR (x, y)) is expressed as in Expression (7).

Therefore, (R _TR (x, y), G _TR (x, y), B _TR (x, y)) is calculated as in equation (8).

The correction of the transmittance may be obtained by the equation (8), or a lookup table in which the input gradation value, the light source intensity distribution value and the transmittance are associated with each other in advance is referred to and transmitted. The structure which calculates | requires a rate may be sufficient.

Based on the corrected transmittance (R _TR (x, y), G _TR (x, y), B _TR (x, y)), the gradation value of the corrected image displayed on the liquid crystal panel 103 is (R _out (x , y), G _out (x, y), B _out (x, y)). The gradation value R _out (x, y) of the corrected image is obtained by inverse gamma conversion of the corrected transmittance R _TR (x, y) as shown in Equation (9). (The same applies to G _out (x, y) and B _out (x, y).)

If (R _out (x, y), G _out (x, y), B _out (x, y)) exceeds the displayable range on the LCD panel 103, (R _out (x, y), G _out (x, y), B _out (x, y)) is corrected to the maximum value (R _out MAX, G _out MAX, B _out MAX) of the displayable range (hereinafter, clipping process). If the corrected gradation value is ( _R'out (x, y), _G'out (x, y), _B'out (x, y)), then ( _R'out (x, y), _G'out (x, y), B ′ _out (x, y)) can be obtained by the following equation.

When R _out > R _outMAX R ' _out (x, y) = R _outMAX (x, y) 
When G _out > G _outMAX G ' _out (x, y) = G _outMAX (x, y) 
B _'out> B B when the _{outMAX' out (x, y)} = B outMAX (x, y)
Also,
When R _out ≤ R _outMAX R ' _out (x, y) = R _out (x, y)
When G _out ≤ G _outMAX G ' _out (x, y) = G _out (x, y)
When B ' _out ≤ B _outMAX B' _out (x, y) = B _out (x, y)
For the gradation value,
(1) Gradation characteristics such that the higher the curve and the higher the value, the gentler the slope of the curve,
(2) The gradation value is linear according to a gradation characteristic in which the slope of the curve becomes gentler as the gradation value is higher when the gradation value is small, and when the gradation value is large, the curve is higher and higher. The gradation may be corrected by rounding to a displayable range. In this embodiment, the gradation is corrected independently for each color component. However, the gradation is maintained with the color ratio for each color component so that the RGB ratio of the input video signal can be displayed. May be corrected.

The panel control unit 104 displays the corrected video signal 115 in the display area on the liquid crystal panel 103. Further, the light source control unit 102 controls the backlight 101 to emit light having an intensity according to the light source intensity 114 (S210).

Here, the effect of this embodiment will be described.

5 and 6 are diagrams illustrating an example of a method for setting the light source intensity of each color light source.

Consider a case where the intensity of a light source is set for an image as shown in FIG. In FIG. 5, 302 indicates a white region of (R, G, B) = (255, 255, 255). 301 indicates an area of (R, G, B) = (150, 0, 0). When an average light source intensity is set by a method using an average value of gradation values for each color component and a histogram, which is one of the conventional methods, 404 (R ′ _ave ) and 405 (G ′ _ave ) in FIG. , 406 (B ′ _ave ).

In the image of FIG. 5, the region where the R component is generally stronger than the G and B components occupies most of the entire image. Therefore, when the average light source intensity is set, In comparison, the R component emits strong light. However, since the region 302 takes the maximum value for both RGB components, if the light source emits light with an intensity of 404, 405, or 406, the G and B components do not emit enough light to display white. Therefore, as a display image, the 302 area is displayed not in white but in a reddish color, and the color of the input image is shifted.

On the other hand, according to the light source intensity setting method of the present invention, the maximum value 401 (R _max ), 402 (G _max ), and 403 (B _max ) for each color component is multiplied by the gain 127 to obtain each color. The light source intensity is determined. Therefore, the light source intensity (R _BL, G _BL, B _BL ) of each color is set as 407, 408, 409. Since the light source intensities 407, 408, and 409 hold the ratio of the maximum value for each color component, all the pixels in the screen can be displayed without causing a color shift. The white color 302 can also be displayed without causing a color shift. On the other hand, regarding the red region 301, if the light is emitted with the maximum values 401, 402, and 403, the intensity is too strong and image quality deterioration may occur due to light leakage. Since the light source intensity is set to the average level while maintaining the above, it is possible to prevent the image quality from being deteriorated due to light leakage because the light emission intensity is too strong. Further, although the G and B components emit extra light, the occurrence of color misregistration can be prevented by lowering the transmittance of the liquid crystal panel 103 of the G and B components.

7 and 8 are diagrams illustrating another example of the method of setting the light source intensity of each color light source.

Consider a case where the intensity of a light source is set for an image as shown in FIG. In FIG. 7, it is assumed that 502 is a region of (R, G, B) = (0, 255, 0), and 501 is a region of (R, G, B) = (150, 0, 20). When an average light source intensity is set by using an average value of a gradation value for each color component and a histogram, 604 (R ′ _ave ), 605 (G ′ _ave ), and 606 (B ′ _ave ) in FIG. It takes a value like this. In the image of FIG. 7, the correction intensity value R ′ _max matched to the level of the intensity value 11 while maintaining the ratio of the maximum values 601 (R _max ), 602 (G _max ), and 603 (B _max ) for each color component. , B ′ _max is below the intensity values 113R ′ _ave , B ′ _ave . In this method, the intensity values 113R _'ave, B' _ave a correction intensity value R _'max, B' by comparing the magnitude of _max, R _'max, B' if _{the max} is below R _'ave, B' _ave R ′ _ave and B ′ _ave are set to the light source intensities R _BL and B _BL, and the light source intensities for the respective color components are as shown by 607, 608, and 609. As a result, color shift due to insufficient light emission of the G component light source in the 502 region and color shift due to insufficient light emission of the R and B component light sources in the 501 region are prevented. As described above, as shown in FIG. 5, in addition to the color shift in the achromatic color region, the color shift in the chromatic color region can also be prevented.

According to this embodiment, even when a plurality of color light sources are provided and the light source intensity of each color is controlled independently, the intensity of the light source is maintained while maintaining the chromaticity formed by the maximum value for each color component of the input video. By setting, it is possible to display an image that does not cause a color shift of the display image without significantly reducing the brightness.

[Second Embodiment]
FIG. 9 is a diagram showing a liquid crystal display device 900 of this embodiment. In the configuration of the present embodiment, in addition to the configuration of the first embodiment, the color light source of the backlight 700 includes a plurality of light sources 130 whose intensities can be controlled independently, and the liquid crystal panel uses the light source intensity of each light source. An intensity estimation unit 702 that estimates the intensity of incident light is provided. In the first embodiment, in all of the light sources 130 in the backlight 101 of FIG. 3, the light intensity of the R light source 131 is the same, and the G light source 132 and the B light source 133 are collectively controlled in the same manner. On the other hand, in the present embodiment, the intensities of the R light source 131, the G light source 132, and the B light source 133 are individually set for each light source 130. An area obtained by virtually dividing the display area of the liquid crystal panel 103 determined based on the spatial arrangement on the backlight 101 for each light source 130 is defined as an illumination area. An illumination area of the input video signal 110 displayed in the vicinity of the position of each color light source is predetermined for each light source 130, and the intensity of the light source is calculated according to the pixels in the illumination area.

The calculating unit 105 calculates the maximum value (hereinafter referred to as “for each color component”) in each of the R, G, and B signal values in the illumination area of the input video signal 111. An intensity value 112 of the light source 130 set based on the obtained maximum value is calculated.

The calculation unit 106 calculates an average value for each color component in the illumination area of the input video signal 111. The intensity value 113 of the light source 130 set based on the obtained average value is calculated.

The intensity estimation unit 702 estimates the intensity (hereinafter referred to as intensity distribution) 703 of light incident on each pixel position of the liquid crystal panel 103 when the backlight 101 irradiates the liquid crystal panel 103 with light according to the light source intensity 114. Specifically, the light source intensity distribution 703 for each color component at the position (x, y) is performed by performing a convolution operation shown in Expression (10) on the light source intensity 114 of each region and the light emission intensity distribution of the light source obtained in advance. Seeking.

Incidentally, M, N (both odd) is, R _BL indicating the horizontal and vertical sizes of the respective light emission intensity distribution _{(x, y), G BL} (x, y), B BL (x, y) is , The intensity of each color light source in the region including the coordinates (x, y), P _r (i, j), Pg (i, j), Pb (i, j) are the light emission for each color component at the position (i, j) Indicates the intensity value of the intensity distribution. For the region corresponding to the outline of the image, the light source intensity 114 is specularly reflected to perform the convolution operation of Expression (10), and BL _R (x, y), BL which is the light source intensity distribution 703 for each color component. _G (x, y), BL _B (x, y) are obtained.

The light source intensity distribution 703 calculated by the intensity estimation unit 702 is input to the signal correction unit 108. Regarding the transmittance correction, the corrected video signal 115 is obtained as in the first embodiment by using the input video signal 111 and the light source intensity distribution 703 as the light source intensity.

The corrected video signal 115 corrected by the signal correction unit 107 is sent to the panel control unit 104. The panel control unit 104 displays the received corrected video signal 115 on the liquid crystal panel 103.

According to the liquid crystal display device of this embodiment, even when the backlight has a plurality of light sources, each light source emits light of a plurality of colors, and the light source intensity of each color is controlled independently, By maintaining the chromaticity of the maximum value for each color component and setting the intensity of the light source, it is possible to display an image that does not cause a color shift of the displayed image without a significant decrease in brightness. I can do it.

DESCRIPTION OF SYMBOLS 100, 900 ... Liquid crystal display device 101, 700 ... Back light, 102 ... Light source control part, 103 ... Liquid crystal panel, 104 ... Panel control part, 105 ... Calculation part, 106. ..Calculating unit 107... Light source intensity calculating unit 108... Signal correcting unit 109... Converting unit 702.

DESCRIPTION OF SYMBOLS 110 ... Input video signal, 111 ... Input video signal, 112 ... Intensity value, 113 ... Intensity value, 114 ... Light source intensity, 115 ... Correction video signal, 703 ... Intensity distribution

122... Gain calculation unit, 123... Strength calculation unit, 127.

130 ... light source, 131 ... R light source, 132 ... G light source, 133 ... B light source

Claims (5)

A backlight provided with a plurality of light sources each having a color light source that emits light of a different color;
A liquid crystal panel that displays an image in a display area by modulating light from the backlight; and
For each color component corresponding to the color light source, based on the maximum value of the input video signal in the illumination area obtained by virtually dividing the display area based on the spatial arrangement of the light sources, the first of the color light sources A first calculation unit for obtaining an intensity;
A second calculation unit that obtains a second intensity of the color light source based on an average value of the input video signal in the illumination area for each color component corresponding to the color light source;
The gain is calculated from the ratio between the maximum value of the first intensity or the value indicating the brightness of the first intensity and the maximum value of the second intensity or the value indicating the brightness of the second intensity. A third calculation unit for calculating;
A light source intensity calculator for calculating a light source intensity from a third intensity of the color light source obtained by multiplying the first intensity by the gain;
An estimation unit that estimates a distribution of light emitted by the backlight when the color light source emits light according to the light source intensity;
A correction unit for obtaining a corrected video signal obtained by correcting the input video signal based on the distribution;
A light source controller that controls the light source according to the light source intensity;
A panel controller for controlling the liquid crystal panel according to the corrected video signal;
A liquid crystal display device comprising:
2. The liquid crystal display device according to claim 1, wherein the light source intensity calculation unit sets the first intensity as the light source intensity when the second intensity is higher than the first intensity.
3. The liquid crystal display device according to claim 2, wherein the light source intensity calculation unit compares the third intensity with the second intensity and sets a larger value as the light source intensity.
The liquid crystal display device according to claim 3, wherein the light source intensity calculation unit calculates the second intensity from a value obtained by multiplying an average value for each color component of the input image signal by a coefficient.
A backlight having a plurality of color light sources each emitting light of a different color;
A first calculation unit for determining a first intensity of the light source based on a maximum value of an input video signal for each color component corresponding to the color of the light source;
A second calculation unit for obtaining a second intensity of the light source based on an average value of the input video signal for each color component corresponding to the color of the light source;
The gain is calculated from the ratio between the maximum value of the first intensity or the value indicating the brightness of the first intensity and the maximum value of the second intensity or the value indicating the brightness of the second intensity. A third calculation unit for calculating;
A third calculation unit that calculates a light source intensity from a third intensity obtained by multiplying the maximum value of the input video signal by the gain for each color component;
A correction unit for obtaining a corrected video signal obtained by correcting the input video signal according to the light source intensity;
A liquid crystal panel for modulating light from the backlight;
A panel controller for controlling the liquid crystal panel according to the corrected video signal;
A light source control unit for controlling the light intensity of the light source according to the light source intensity;
A liquid crystal display device comprising:

Images