JP2007322944A - Display control device, display device, and display control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display control device for improving image quality displayed in a display device using a backlight, and also to provide the display device and a display control device thereof. <P>SOLUTION: A control part 20 of the liquid crystal display device 10 comprises: a video signal detection circuit 19 for detecting a video signal; a backlight lighting control circuit 15 for controlling lighting of the backlight 42; and a liquid crystal panel control circuit 14 for controlling drive of a liquid crystal panel 13 of the liquid crystal display device 11. The backlight lighting control circuit 15 individually controls a brightness ratio of each LED element 31 of RGB in a plurality of light source blocks 40 in response to a plurality of regions divided by a display screen of the liquid crystal display device 11 in response to the input video signal. The brightness ratio of each LED element 31 of RGB is controlled by applying a PWM signal on current quantity control elements 44(R), 44(G), and 44(B) composed of FETs or the like. Thereby color purity is enhanced, and a high quality image is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device that displays an image by controlling the transmittance of a backlight, a display control device that controls the display device, and a control method therefor.

  In a display device that controls the light transmittance and displays an image, for example, a liquid crystal display device, since a pixel of the liquid crystal panel does not emit light, a backlight is disposed on the back side of the liquid crystal panel, and the backlight uses the backlight of the liquid crystal panel. The back is illuminated to display the image. Recently, an LED (Light Emitting Diode) is often used as the backlight.

  Also, a method of dividing the display screen into a plurality of regions corresponding to each light source constituting the backlight, and partially suppressing the light emission luminance of the light source corresponding to the display luminance required for each divided region Has been proposed (see, for example, Patent Document 1). Thereby, power consumption is reduced.

  The above-mentioned “light emission luminance” means the luminance when light is emitted from the light source, and the above “display luminance” means that the light emitted from the light source is transmitted through the display unit (display screen). Of the brightness (hereinafter the same).

JP 2004-212503 A (paragraph [0035])

  By the way, although the power consumption is reduced by partially changing the light emission luminance as described above, there is an increasing demand not only for the power consumption reduction but also for the image quality itself.

  In view of the circumstances as described above, an object of the present invention is to provide a display control device, a display device, and a display control method capable of improving the image quality displayed on a display device using a backlight.

  In order to achieve the above object, a display control apparatus according to the present invention changes the light transmittance for each pixel, thereby displaying a video according to an input video signal on a display screen. A backlight having a light source block that emits the light of the three primary colors, and a plurality of the light source blocks arranged corresponding to a plurality of areas into which the display screen is divided, and the video signal A chromaticity signal detecting means for detecting a chromaticity signal, and a luminance ratio control means for individually controlling the luminance ratio of the light of the three primary colors for each of the light source blocks in accordance with the detected chromaticity signal. A display control apparatus comprising:

  In the present invention, since the luminance ratio of the three primary colors is individually controlled for each light source block, that is, for each display screen area, according to the chromaticity signal of the video signal, the color purity can be increased and the image quality can be improved. Can be achieved.

  More specifically, “control according to the chromaticity signal” means that when a certain area of the display screen has the first chromaticity, the light source block corresponding to that area is the first light source block. The luminance ratio is controlled so as to emit light as close as possible to chromaticity or light having the same chromaticity as the first chromaticity.

  A “pixel” of a display device is a pixel corresponding to one of the three primary colors.

  In the present invention, the display control apparatus further includes a transmittance control unit that controls the transmittance of each pixel in accordance with the control by the luminance ratio control unit. In the present invention, the luminance ratio control means and the transmittance control means operate complementarily to reproduce the chromaticity of the original image.

  In the present invention, the detected chromaticity signal includes a first chromaticity and a second chromaticity different from the first chromaticity in the first region among the regions, and In a second area adjacent to the first area, a second color area displayed continuously with the first color area having the second chromaticity in the first area is the second color area. The first color purity displayed in the first color region is the same as the second color purity displayed in the second color region. A luminance ratio control unit controls the luminance ratio in each of the first and second regions, and the transmittance control unit controls the transmittance of the pixels in the first and second regions.

  In the present invention, the first and second color puritys are set so that the first color purity displayed in the first color region and the second color purity displayed in the second color region are substantially the same. The luminance ratio of each light source block corresponding to the region is controlled, and the first and second transmittances are controlled by the transmittance control means. Therefore, even when the number of light emitting elements of a certain single color per unit area is low on one display screen, it is possible to suppress the occurrence of color unevenness in the displayed image.

  In the present invention, the display control device detects a luminance signal from the video signal, storage means for storing data of a contribution ratio of display luminance to each area of the display screen when each light source block emits light. A luminance distribution setting unit that sets a light emission luminance distribution of each of the light source blocks according to the detected display luminance using the stored contribution rate data, and the set luminance distribution It further includes lighting control means for lighting the backlight.

  In the present invention, since the light emission luminance distribution of the light source block is set for each area of the display screen, an image with a high contrast ratio can be displayed. Further, “data of the display luminance contribution ratio for each area of the display screen when each light source block emits light” means the display luminance contribution ratio for all areas affected by one light source block. It is data. That is, since the influence on each area of the display screen by the plurality of light source blocks is taken into consideration, the original image can be faithfully reproduced.

  In the present invention, when the backlight is turned on by the lighting control unit, the luminance ratio control unit may control the luminance ratio of the light source blocks in the entire area of the display screen to be equal. This simplifies control.

  The display device according to the present invention includes a display device that displays an image corresponding to an input video signal on a display screen by changing light transmittance for each pixel, and a light source block that emits the light of the three primary colors. And a backlight configured by arranging a plurality of the light source blocks corresponding to a plurality of areas into which the display screen is divided, and a chromaticity signal detecting means for detecting a chromaticity signal among the video signals, And a luminance ratio control means for individually controlling the luminance ratio of the light of the three primary colors for each of the light source blocks in accordance with the detected chromaticity signal.

  The display control method according to the present invention includes a display device that displays an image corresponding to an input video signal on a display screen by changing light transmittance for each pixel including three primary colors, and the three primary colors. A display control method for a display device, comprising: a light source block that emits light; and a backlight configured by arranging a plurality of the light source blocks corresponding to a plurality of regions into which the display screen is divided, A step of detecting a chromaticity signal in the video signal; and a step of individually controlling a luminance ratio of the light of the three primary colors for each of the light source blocks in accordance with the detected chromaticity signal.

  As described above, according to the present invention, color reproducibility can be improved and image quality can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram showing a display device according to an embodiment of the present invention. The display device 10 is a liquid crystal display device in which liquid crystal is mounted as a device that changes the light transmittance for each pixel, for example.

  The liquid crystal display device 10 controls the liquid crystal display device 11 that displays an image, the backlight 42 disposed on the back side of the liquid crystal display device 11, and various controls for the backlight 42 and the liquid crystal display device 11. Unit 20 and a memory 16 accessible by the control unit 20. The control unit 20 includes a video signal detection circuit 19 that detects a video signal, a backlight lighting control circuit 15 that controls lighting of the backlight 42, and a liquid crystal panel control circuit that controls driving of the liquid crystal panel 13 of the liquid crystal display device 11. 14.

  The liquid crystal display device 11 has a source driver 17 and a gate driver 18 for sending drive signals to the liquid crystal panel 13. The liquid crystal panel 13 is provided with color filters of three primary colors (RGB) of red, green, and blue (not shown), and one pixel is composed of three sub-pixels corresponding to RGB. The configuration of the liquid crystal panel 13 may be a known configuration. The configuration of the color filter may be a configuration of four or more primary colors including colors other than RGB, for example, colors such as emerald or cyan. Hereinafter, unless otherwise specified, the sub-pixel is described as a “pixel”.

  FIG. 2 is a diagram illustrating an example of a single cell in which RGB LED elements constituting the backlight 42 are arranged. As shown in FIG. 1, the single cell 30 includes a red (R) LED element 31 (R), a green (G) LED element 31 (G), and a blue (B) LED element 31 (B). Each of the two is connected in series with their polarities aligned in one direction, and is composed of a total of six LED elements.

  The unit cell 30 has six configurations in this example. However, the light output balance needs to be adjusted in order to make the mixed color a balanced white light according to the rating of the LED element to be used and the light emission efficiency. Therefore, the number distribution of each color may have a configuration example other than the present embodiment.

  A plurality of single cells 30 are connected to form a backlight 42, but the junction between the single cells 30 is arranged in the center as shown in FIG. 2 so that the polarities of the LED elements of each color are aligned in one direction. Connected by double-ended arrows. FIG. 3 shows an equivalent diagram of FIG.

  The backlight 42 includes a plurality of single cells 30 shown in FIG. In the example shown in FIG. 1, a plurality of blocks represented by “6G6R6B” are arranged vertically and horizontally. Hereinafter, this one block is referred to as a “light source block”. The backlight 42 is configured by arranging 5 × 4 = 20 light source blocks 40. “6G6R6B” means that each of the RGB LED elements 31 (R), 31 (G), and 31 (B) is provided in six by connecting three single cells 30 in cascade. To do. That is, one light source block 40 includes three single cells 30 and a total of 18 LED elements, and the backlight 42 includes 360 LED elements.

  Note that the number of single cells 30 included in one light source block is not three, but may be one or four or more.

  FIG. 4 is a schematic diagram showing the arrangement of the liquid crystal panel 13 and the backlight 42. The light source blocks 40 are arranged in a matrix on the back side of the liquid crystal panel 13. Specifically, the display screen of the liquid crystal panel 13 is divided into 4 × 5 = 20 areas A, B, C,..., T, and the light source blocks 40 are arranged so as to correspond to the divided areas. Has been. Ideally, each light source block 40 is desirably provided with the LED element 31 (R), the LED element 31 (G), and the LED element 31 (B) corresponding to one pixel of the liquid crystal panel 13. Due to problems such as heat generation and cost, the configuration shown in FIG. The light emitted from each light source block 40 is diffused by a scattering plate or a scattering sheet (not shown) and applied to the back surface of the liquid crystal panel 13.

  The number of light source blocks 40 included in the backlight 42 can be changed as appropriate. As will be described later, when the backlight 42 is controlled so as to maintain uniform luminance, the number of the light source blocks 40 may be simply one. In addition, the backlight 42 is configured to be arranged in a matrix in the XY direction (vertical and horizontal directions), but may be configured to be disposed only in one of the X direction and the Y direction. In this case, one light source block 40 is configured to be vertically long or horizontally long as illustrated.

  FIG. 5 is a block diagram showing a specific configuration of the control unit 20 and the backlight lighting control circuit 15 in the liquid crystal display device 10. The backlight lighting control circuit 15 includes a calculation unit 45, a power supply unit 43, current amount control elements 44 (R), 44 (G) and 44 (B), and a PWM signal generation unit 56.

  The power supply unit 43 includes a power supply unit 43 that individually supplies power to each light source block 40 by setting a power supply voltage supplied from a primary power supply (not shown) to a predetermined constant voltage. The power supply unit 43 is configured by a switching regulator, for example.

  Current amount control elements 44 (R), 44 (G), and 44 (B) are provided for each light source block 40, and each LED element 31 (R), 31 (G), and 31 (B) of the light source block 40 is provided. It is an element that controls the amount of applied current. The current amount control elements 44 (R), 44 (G), and 44 (B) are configured by, for example, FETs (Field Effect Transistors).

  The PWM signal generator 56 outputs a PWM signal for each of the current amount control elements 44 (R), 44 (G), and 44 (B). When the current amount control elements 44 (R), 44 (G), and 44 (B) are FETs, the PWM signal functions as a gate signal. The PWM signal generator 56 drives each LED element 31 (R), 31 (G), and 31 (B) by PWM, and the RGB light emission luminance is controlled for each light source block 40. Thereby, the chromaticity of each light source block 40 is individually controlled. The PWM signal generator 56 controls the luminance of each light source block 40 to be uniform over the entire display screen.

  The computing unit 45 sets chromaticity for each light source block 40 according to the video signal, and sets the brightness of the entire backlight 42. When the luminance of the backlight 42 is set, the arithmetic unit 45 sends a drive signal to each of the current amount control elements 44 (R), 44 (G), and 44 (B) for each light source block 40 so that the luminance is obtained. Then, control is performed so as to be uniform over the entire display screen as described above.

  Note that the arithmetic unit 45 preferably monitors the amount of current applied to each light source block 40 and feeds back a control signal to the power supply unit 43 so that a stable current is always supplied to each light source block 40.

  The video signal detection circuit 19 includes a luminance signal detection circuit 25 that detects a luminance signal in the video signal, and a color signal detection circuit 26 that detects a color signal.

  When a video signal is input to the video signal detection circuit 19, the liquid crystal panel control circuit 14 generates a display drive signal for performing display drive on the liquid crystal panel 13 based on the input video signal. The generated display drive signal is sent to the source driver 17 and the gate driver 18 of the liquid crystal panel 13 and input to each pixel of the liquid crystal panel 13 via the source driver 17 and the gate driver 18. The display drive signal is input in one field period or one frame period in synchronization with the field period or frame period of the input video signal. In the case of the interlace method, one field consists of two frames, and in the case of the progressive method, one field consists of one frame. Hereinafter, “one field or one frame” is simply referred to as “one field”.

  In many cases, the memory 16 mainly functions as a temporary buffer of the control unit 20. The memory 16 is preferably a semiconductor memory or a dielectric memory, but is not limited thereto, and may be a memory using other magnetism or light.

  The operation of the liquid crystal display device 10 configured as described above will be described. FIG. 6 is a flowchart showing the operation. The series of operations shown in FIG. 6 is performed every time a video signal for one field is input.

  For example, a video signal for one field is input to the control unit 20 (step 601). FIG. 7A shows an example of the video. In this video, for example, there is a mountain at the bottom, and the sky and the sun above the mountain. When the video signal is input, the video signal detection circuit 19 detects the luminance signal and the chromaticity signal (step 602).

  The computing unit 45 obtains the peak luminance value in one field according to the luminance signal, and sets the luminance of the entire backlight 42 by matching the luminance values of all the light source blocks 40 with the peak value (step 603). ). Note that the luminance may not be adjusted to the peak value, but may be adjusted to the average value, median value, or minimum value in one field. In the image example shown in FIG. 7A, when the display brightness of the regions D and H where the sun is located is the highest, when the brightness of the entire backlight 42 is adjusted to the peak value, FIG. As shown, all the light source blocks 40 are set to have the light emission luminance of the light source blocks 40 corresponding to the regions D and H, for example.

  Moreover, the calculating part 45 calculates the luminance ratio of each LED element 31 (R), 31 (G), and 31 (B) for every light source block 40 according to a chromaticity signal (step 604). Thereby, the chromaticity by light emission for each light source block 40 corresponding to each region A to T of the display screen is individually set.

  For example, referring to FIG. 7B, since the sun is displayed in the regions D and H, the respective light sources are arranged so that the light emission color of the light source block 40 corresponding to the regions D and H is, for example, white or light yellow. The luminance ratio of each LED element 31 (R), 31 (G), and 31 (B) in the block 40 is set. Further, for example, in the video example, the color of the mountain is green and the display chromaticity of the areas Q, R, S, T, etc. (the chromaticity corresponding to the chromaticity signal of the video signal, When the chromaticity displayed on the display screen is the deepest green, the calculation unit 45 sets the emission chromaticity of the light source block 40 corresponding to each of the regions Q, R, S, T, and the like to deep green. In this case, for example, the calculation unit 45 reduces the luminance of the red LED element 31 (R) and / or the blue LED element 31 (B) of the light source block corresponding to the regions Q, R, S, and T, Alternatively, it is set to zero, and the green luminance is set higher than that of the LED element 31 (R) or the like. Further, when the areas A and E are empty and the display chromaticity is blue, the calculation unit 45 relatively increases the luminance of the blue LED element 31 (B) of the light source block 40 corresponding to the areas A and E, for example. To do.

  As described above, although the luminance ratio differs for each light source block 40, the luminance of the entire display screen is controlled to be constant as described in step 603.

  In the case of setting the chromaticity in step 604, in practice, there are many display chromaticities in each region A to T even in one region. In this case, the calculation unit 45 can set the light emission chromaticity of one light source block 40 so as to match the most display chromaticity in the region corresponding to the light source block 40. Alternatively, the calculation unit 45 calculates the center position (center of gravity position) on the chromaticity diagram of a plurality of chromaticities included in the one area, and calculates the emission chromaticity of the light source block 40 corresponding to the area. It is also possible to set to match the calculated chromaticity of the center position.

  On the other hand, the liquid crystal panel control circuit 14 generates a display drive signal for the liquid crystal panel 13 according to the luminance signal and the chromaticity signal (step 605). This display drive signal may be a drive signal for a general liquid crystal panel 13.

  Next, based on the luminance of the backlight 42 set in step 603, the chromaticity of each light source block set in step 604, and the display drive signal generated in step 605, the backlight lighting control circuit 15 and the liquid crystal panel control circuit 14 drive the backlight 42 and the liquid crystal panel 13, respectively (step 606).

  As described above, in the liquid crystal display device 10 according to the present embodiment, the RGB luminance ratio is individually controlled for each light source block 40, that is, for each of the display screen regions A to T, so that the color purity is increased. Image quality can be improved. For example, in the image example shown in FIG. 7B, the deep green color purity in the regions Q, R, S, T, and the like is improved.

  In FIG. 8A, each of the LED elements 31 (R), 31 (G), and 31 (B) emits monochromatic light, and the liquid crystal panel 13 is driven, for example, the maximum luminance gradation (transmittance is almost 100%). FIG. 6 is a diagram showing primary color chromaticity points (R, G, B) displayed on the display screen when displayed in (). FIG. 8B is a graph showing the RGB spectrum displayed on the display screen at that time. In FIG. 9A, each of the LED elements 31 (R), 31 (G), and 31 (B) emits light with the same luminance (for example, the highest luminance), and the liquid crystal panel 13 is driven to transmit a single color. It is a figure which shows the primary color chromaticity point (R ', G', B ') displayed on a display screen when a rate is displayed at about 100%. FIG. 9B is a graph showing the RGB spectrum displayed on the display screen at that time.

  As shown in FIGS. 8A and 8B, the case where each LED element 31 (R), 31 (G), and 31 (B) emits monochromatic light is shown in FIGS. 9 (A) and (B). It can be seen that the color purity is higher than in the case of.

  In the embodiment described above, the liquid crystal panel control circuit 14 has shown the form in which the display drive signal of the liquid crystal panel 13 is generated by a general method according to the luminance signal and the chromaticity signal in step 605. However, the liquid crystal panel control circuit 14 can also perform display control of the liquid crystal display device 11 in a complementary manner to the control of the backlight lighting control circuit 15. For example, the liquid crystal panel control circuit 14 generates a driving signal for the liquid crystal panel 13 by a general method in accordance with the luminance signal and the chromaticity signal, and then the emission color for each light source block 40 of the backlight lighting control circuit 15. The generated drive signal may be corrected to match the degree control. 7B, when the light source block 40 in the areas Q, R, S, and T emits green monochromatic light, the liquid crystal panel control circuit 14 displays, for example, green more vividly. It is also possible to set the transmittance of all the pixels in the regions Q, R, S, and T to be almost 100%.

  In step 603, the backlight lighting control circuit 15 is set so that the luminance of the entire display screen is different for each field. By controlling the luminance for each field, it is possible to reduce power consumption as compared with the conventional backlight driving that always emits white light with high luminance. However, it is not always necessary to perform luminance control for each field according to the video signal. For example, as in a conventional general backlight, the luminance of the entire display screen may be controlled to be constant regardless of the video signal. In this case, for example, the calculation unit 45 can set the luminance of the display screen in accordance with a setting signal of arbitrary luminance by the user or a detection signal by a sensor (not shown). The sensor is, for example, an illuminance sensor that detects the ambient brightness on which the liquid crystal display device 10 is placed. For example, the calculation unit 45 sets a predetermined luminance according to the ambient brightness.

  Next, an operation according to another embodiment of the liquid crystal display device 10 will be described. In this operation, a case where a video example as shown in FIG. 10 is displayed will be described.

  The video shown in FIG. 10A is a video for one field. For example, it is assumed that a white region 28 is present in a red background. In this video example, as shown in FIG. 10B, the backlight lighting control circuit 15 sets the emission color of the light source block 40 corresponding to the area F of the display screen to white and continues to the area 29. The backlight 42 is turned on by setting the emission colors of the red areas A to E and G to T to a single red color. At this time, the liquid crystal panel control circuit 14 drives the liquid crystal panel 13 with a general drive signal based on the video signal, or the transmittance of all the RGB pixels corresponding to the regions A to E and GT. Is driven to almost 100%. At this time, the following problems occur.

  Regions A to E and G to T can be displayed in deep red with high color purity. However, since the light source block 40 corresponding to the region F emits white light and the region 29 around the white region 28 is displayed in red by driving the liquid crystal panel 13, the red color in the surrounding region 29 is generally used. Red due to a liquid crystal display device. Therefore, in the surrounding area | region 29, it becomes light red compared with deep red with high color purity of area | regions AE and GT. As a result, color unevenness occurs in red on the entire display screen. This is because even if the display color through the liquid crystal around the white region 28 closes the green and blue of the liquid crystal pixels, the green and blue light leaks somewhat from the red pixels.

  Here, in one display screen, the number per unit area (hereinafter simply referred to as density) of a certain single color LED element is higher, and the number of control units of the single color LED element by the backlight lighting control circuit 15 is larger. There is no problem to some extent. However, if the density is low, in order to display the white color of the white region 28, the LED elements in the region 29 around the white region 28 need to emit white light. On the other hand, if the density is too high, problems of heat generation and cost occur. In order to solve such a problem, the liquid crystal display device 10 operates as follows.

  FIG. 11 is a flowchart showing the operation. In the operation of FIG. 11, steps 1101 to 1103 are the same as steps 601 to 603 shown in FIG. For example, when the backlight lighting control circuit 15 displays an image as shown in FIG. 10A, the display chromaticity of red in the areas A to E and GT is changed to the light red color of the surrounding area 29 in the area F. The luminance ratios of the LED elements 31 (R), 31 (G), and 31 (B) of the light source blocks 40 in the regions A to T are set so as to match the display chromaticities of Step 1104). The liquid crystal panel control circuit 14 also sets the transmittance of each pixel so that the red display chromaticity of the areas A to E and G to T matches the light red display chromaticity of the surrounding area 29 in the area F. (Step 1105). That is, the backlight lighting control circuit 15 and the liquid crystal panel control circuit 14 make the red display chromaticity of the areas A to E and GT to the light red display chromaticity of the surrounding area 29 in the area F the same. Thus, the luminance ratio and the transmittance are set complementarily.

  Specifically, for example, the calculation unit 45 causes the LED elements 31 (R), 31 (G), and 31 (B) corresponding to the region F to have a luminance ratio of 1: 1: 1, and emit light at the maximum luminance. In this case, the luminance ratio of the LED elements 31 (R), 31 (G), and 31 (B) corresponding to the regions A to E and G to T is set to, for example, 1: 0.1: 0.1. .

  Further, the liquid crystal panel control circuit 14 sets, for example, the transmittance of RGB pixels in the white region 28 in the region F to 100% and sets the transmittance ratio of RGB pixels in the surrounding region 29 to 1: 0: 0. . In the case of 1: 0: 0, R is 100%, and G and B are each 0%. Further, the liquid crystal panel control circuit 14 sets, for example, all the RGB transmittances corresponding to the regions A to E and G to T to 100%. In this way, the liquid crystal panel control circuit 14 sets the transmittance with binary values of ON / OFF.

  Then, the backlight lighting control circuit 15 and the liquid crystal panel control circuit 14 drive the backlight 42 and the liquid crystal panel 13 respectively according to the luminance ratio and transmittance set in this way (step 1106).

  FIG. 12 is a diagram schematically showing the LED elements of the liquid crystal panel 13 and the backlight 42 at this time. 12A corresponds to the white area 28 in the area F, and FIG. 12B corresponds to the surrounding area 29 in the area F. FIG. 12C corresponds to regions A to E and G to T. In FIG. 12, reference numeral 36 is an RGB color filter, and reference numeral 38 is a liquid crystal.

  In FIG. 12, for easy understanding, the LED elements 31 (R), 31 (G), and 31 (B) are drawn so as to correspond to each RGB pixel. However, actually, each LED element 31 (R), 31 (G), and 31 (B) does not correspond to one pixel, and one LED element corresponds to a predetermined plurality of pixels.

  As described above, the LED elements 31 (R) of the regions A to T are adjusted so that the red display chromaticities of the regions A to E and G to T match the light red display chromaticity of the surrounding region 29 in the region F. ), 31 (G) and 31 (B) are set, and the transmittance of the liquid crystal in each of the regions A to T is set, so that the occurrence of the color unevenness can be suppressed.

  In the above step 1105, the liquid crystal panel control circuit 14 is configured to set the transmittance with 1 bit of ON / OFF, but the gradation setting of 2 bits or more may be used. In that case, the transmittance is set to be complementary to the luminance of each LED element 31 (R), 31 (G), and 31 (B) by the backlight lighting control circuit 15. For example, when the image of FIG. 10A is displayed, when the luminance ratio of the RGB LED elements shown in FIG. 12C is 1: 0.2: 0.2, transmission of the RGB pixels of the liquid crystal 38 is performed. The rate may be set such that R is 100%, G is 50%, and B is 50%. The luminance ratio, transmittance, or transmittance ratio described above is merely a simple example for easy understanding of the description, and various brightness ratios, transmittances, or transmittance ratios can be set.

  Next, a mode in which the luminance partially changes in the display screen displayed on the liquid crystal display device 11 by individually controlling the luminance of each light source block of the backlight 42 will be described.

  FIG. 13 shows another embodiment of the backlight. In the liquid crystal display device mounted with the backlight 12, the configuration other than the backlight 12 is the same as the configuration shown in FIG. In the following description, the description of the same members and functions of the liquid crystal display device 10 according to the embodiment shown in FIG. 1 will be simplified or omitted, and different points will be mainly described.

  The backlight 12 includes the above-described light source block, for example, nine light source blocks 1, 2,. The light source blocks 1, 2,..., 9 are arranged immediately behind the nine areas A 1 to A 9 of the display screen of the liquid crystal panel 13.

  Here, in order to simplify the description, as an example of the backlight 12, the light source blocks 1 to 9 are illustrated as being divided and arranged only in the vertical direction. Actually, as shown in FIG. 1, it is preferable to use a light source block that is divided and arranged in both the vertical direction and the horizontal direction. Alternatively, the light source block may be one in which the light source is divided and arranged only in the horizontal direction. FIG. 13 shows an example in which the display screen area is divided into nine. However, the display screen area may be smaller or larger than nine, but is preferably as large as possible.

  Moreover, each area | region A1-A9 of a display screen is not set as an area | region where the light radiate | emitted only from the light source blocks 1-9 located right behind reaches | attains. Therefore, the light emitted from each of the light source blocks 1 to 9 reaches a region other than the region located immediately before by the scattering plate or the like, as will be described later.

  FIG. 14 is a block diagram showing the configuration of the liquid crystal display device according to the present embodiment, and particularly shows the configuration of the control unit 20 and the memory 16 (see FIG. 1). The control unit 20 of the liquid crystal display device 100 includes a video signal detection circuit 19, a light emission luminance distribution setting unit 21, a liquid crystal panel control circuit 14, and a backlight lighting control circuit 115. The memory 16 includes a light emission luminance distribution data storage unit 35 and a display luminance contribution rate data storage unit 37.

  The light emission luminance distribution setting unit 21 sets the light emission luminance distribution of each of the light source blocks 1 to 9 according to the luminance signal detected by the luminance signal detection circuit 25. The light emission luminance distribution data storage unit 35 stores the light emission luminance distribution of the set light source blocks 1 to 9. In many cases, the emission luminance distribution data storage unit 35 mainly functions as a temporary buffer.

  The display luminance contribution rate data storage unit 37 stores display luminance contribution rate data that the light source blocks 1 to 9 affect the areas A1 to A9.

  The backlight lighting control circuit 115 individually controls driving of the light source blocks 1 to 9 according to the light emission luminance distribution set by the light emission luminance distribution setting unit 21. Specifically, the backlight lighting control circuit 115 outputs a predetermined control signal to the PWM signal generator 56 so that the luminance of each of the light source blocks 1 to 9 becomes a predetermined luminance.

  FIG. 15 is a diagram illustrating an example of the light emission luminance of each of the light source blocks 1 to 9. In FIG. 15, the horizontal axis indicates the position in the vertical direction of the display screen, the vertical axis indicates the light emission luminance, and is an example in which each of the light source blocks 1 to 9 emits light with substantially the maximum uniform luminance. The brightness is shown. Specifically, the value on the vertical axis is a value when the total light emission luminance of each of the regions A1 to A9 is normalized to 1 when each of the light source blocks 1 to 9 emits light at substantially maximum luminance. . In the case of the example shown in FIG. 15, the maximum value of the light emission luminance by one light source block among the light source blocks 1 to 9 is about 0.44 to 0.45, but it is needless to say that the value is not limited to this value.

  In the liquid crystal display device 100, a partition or the like for preventing the light emitted from each of the light source blocks 1 to 9 from reaching an area other than the area located immediately before each of the light source blocks 1 to 9 is provided. Not provided. Therefore, the light emitted from each of the light source blocks 1 to 9 reaches another area other than the area located immediately before, and contributes to the display luminance in the other area.

  FIG. 16 shows the luminance contribution ratio of each light source block to each position of the display screen when the emitted light is incident on the liquid crystal panel 13 when each light source block having the light emission luminance shown in FIG. 15 is used. It is a thing. The horizontal axis represents the position in the vertical direction of the display screen, and the vertical axis represents the luminance contribution ratio to the display luminance of the light emitted from each light source block 1-9.

  As shown in FIG. 16, the luminance contribution ratio of the light emitted from each of the light source blocks 1 to 9 is highest in the corresponding areas A1 to A9 of the light source blocks 1 to 9, respectively, and gradually as the distance from the areas A1 to A9 increases. To drop. In other words, taking only the area A1 as an example, the luminance contribution ratio by the light source block 1 is highest in the area A1 corresponding thereto. Taking only the area A2 as an example, the luminance contribution ratio by the light source block 2 is high in the area A2 corresponding thereto. Further, in the vicinity of the boundary between the areas A1 and A2, the luminance contribution ratios of the light source blocks 1 and 2 intersect, and the combined luminance contribution ratio appears to be high. For the light source blocks 1 and 9 arranged at both ends in the vertical direction, the luminance contribution ratio in the corresponding regions A1 and A9 is about 40%, and for the light source blocks 2 to 8 arranged in the middle position, The luminance contribution ratios in the areas A2 to A8 corresponding to the respective areas are about 20 to 30%. The reason why the luminance contribution ratios in the areas A1 and A9 are high is due to the structure of the liquid crystal panel 13 due to the relationship between the reflecting plate and the scattering plate.

  Thus, in the liquid crystal display device 100, the light emitted from each of the light source blocks 1-9 reaches an area other than the area corresponding to the light source blocks 1-9. That is, each light emitted from each of the light source blocks 1 to 9 is not irradiated to only the corresponding areas A1 to A9 separately, but is irradiated to other areas.

  In the liquid crystal display device 100, it is measured in advance how much the light emission luminance of each of the light source blocks 1 to 9 contributes to the display luminance of the regions A1 to A9, and this measured value is a simultaneous equation described later. The data for calculation is stored in the display luminance contribution rate data storage unit 37. The display luminance contribution rate data need not be stored as data in the display luminance contribution rate data storage unit 37 in advance, and can be derived by calculation in some form of function. Therefore, the display luminance contribution rate data storage unit 37 may not be provided, or the display luminance contribution rate data storage unit 37 may function as a temporary buffer.

  Next, a processing example of control related to screen display will be described with reference to the flowchart of FIG. This control is executed by the liquid crystal panel control circuit 14 and the backlight lighting control circuit 115 of the control unit 20, and is performed every time a video signal of one field is input to the liquid crystal panel control circuit 14.

  When a one-field video signal is input to the liquid crystal panel control circuit 14 (step 1701), the luminance signal detection circuit 25 detects the display luminance distribution of one video (original video) generated by the input video signal. (Step 1702). Therefore, the display brightness of each area A1 to A9, for example, the average display brightness obtained by averaging the display brightness of each part for each area A1 to A9 is detected.

  The light emission luminance distribution setting unit 21 sets the light emission luminance distribution of each of the light source blocks 1 to 9 constituting the backlight 12 based on the detected display luminance distribution (step 1703). When setting the light emission luminance distribution, the luminance contribution ratio of the light emission luminances of the light source blocks 1 to 9 with respect to the display luminances of the regions A1 to A9 is considered. Specifically, each light source is expressed by simultaneous equations (2) to (10) using the display luminance contribution rate data stored in advance in the display luminance contribution rate data storage unit 37 of the memory 16 (see FIG. 16). The light emission brightness of blocks 1 to 9 is set.

  Step 1704 is the same processing as step 604 shown in FIG. That is, the calculation unit 45 calculates the luminance ratio of the LED elements 31 (R), 31 (G), and 31 (B) for each of the light source blocks 1 to 9 according to the chromaticity signal (step 1704). Thereby, the chromaticity by light emission for each of the light source blocks 1 to 9 corresponding to the areas A to T of the display screen is individually set.

  On the other hand, the liquid crystal panel control circuit 14 generates a drive signal for the liquid crystal panel 13 so that the display luminance of the pixels corresponding to the areas A1 to A9 of the display screen of the liquid crystal panel 13 is optimized (step 1705). That is, a drive signal for the liquid crystal panel 13 is generated according to the light emission luminance distribution set in step 1703. More specifically, the drive signal is generated based on the amount of deviation between the set light emission luminance of each of the light source blocks 1 to 9 and the optimum value of the display luminance in each part of the display screen. The optimum value is the display luminance required in each part of the display screen when the original video is displayed based on the input video signal. Accordingly, a deviation amount correction value for correcting the deviation amount is required in each part of the display screen when light is emitted from each of the light source blocks 1 to 9 with the light emission luminance set as described above. It is a value for calculating the transmissivity of the liquid crystal required in each pixel in order to obtain a display luminance of the same. To put it simply, for example, when the light emission luminance of a certain region of each of the regions A1 to A9 is ½ of the constant luminance as in the conventional case, the light of the liquid crystal pixel corresponding to that region. Correction is performed so that the transmittance is doubled.

  Next, the backlight is turned on based on the light emission luminance distribution of the backlight 42 set in step 1703, the chromaticity for each light source block set in step 1704, and the display drive signal of the liquid crystal panel 13 generated in step 1705. The control circuit 115 and the liquid crystal panel control circuit 14 drive the backlight 42 and the liquid crystal panel 13, respectively (step 1706).

  Hereinafter, a specific method of control performed in steps 1701 to 1703 and step 1705 described above will be described.

  If the number of light source blocks of the backlight 12 is N (N is an integer of 2 or more), N = 9 in this example.

  In the liquid crystal display device 100, as described above, the display screen is divided into nine regions A1 to A9 as shown in FIG. 13 with a number corresponding to the number of light source block divisions N (= 9). Has been.

  For each of the regions A1 to A9, the maximum display luminance Ln_max (n = 1 to 9) determined by the input video signal is obtained. The maximum display brightness Ln_max is a value that provides the maximum display brightness in each part of the areas A1 to A9. The maximum display luminance is a value corresponding to the video signal for each field, and is different for each field.

  Here, the display brightness of all white (when the white peak is set for both the liquid crystal panel 13 and the backlight 12 (usually when the transmittance of the liquid crystal panel 13 is 100% and the output of the backlight 12 is 100%)) is L_peak. A ratio αn (n = 1 to 6) of the maximum display luminance Ln_max with respect to the display luminance L_peak of all white is obtained for the regions A1 to A9. Here, Ln_max ≦ L_peak.

αn = (Ln_max / L_peak) (1)
The ratio αn is a recovery limit indicating how much the light emission luminance of the light source blocks 1 to 9 corresponding to the regions A1 to A9 can be suppressed. That is, the display brightness of the liquid crystal panel 13 is roughly determined by “the transmittance of the liquid crystal panel (including the polarizing plate) × the light emission brightness of the backlight”. The recovery limit is that the light emission brightness of the backlight 12 is further reduced. Even if the transmittance of the liquid crystal panel is set to 100%, the maximum display luminance Ln_max cannot be obtained. The recovery limit αn corresponds to the luminance signal of the video signal. In step 1702, the recovery limit αn is obtained.

  In the above, the value of the recovery limit αn is obtained based on the maximum display luminance Ln_max of each of the areas A1 to A9. However, depending on the video content, αn ′ = based on the average display luminance Ln_ave of each of the areas A1 to A9. It is also possible to perform luminance control by obtaining the value of the recovery limit αn ′ by (Ln_ave / L_peak). When the control is performed by obtaining the value of the recovery limit αn ′, it is difficult to reproduce a complete original image, but it is possible to reproduce the original image in a range that is less affected by appearance.

  As described above, the light emission luminances of the other light source blocks 1 to 9 contribute to the display luminances of the respective regions A1 to A9 in addition to the light emission luminances of the light source blocks 1 to 9 corresponding to the regions A1 to A9. Therefore, the light source blocks 1 to 9 that do not correspond to the regions A1 to A9 can be controlled only by controlling the emission luminance of the light source blocks 1 to 9 corresponding to the regions A1 to A9 according to the recovery limits αn of the regions A1 to A9. It is not possible to perform control in consideration of light emission luminance.

  Accordingly, the light emission rate βn (n = 1 to 9) for each of the light source blocks 1 to 9 is obtained in consideration of the light emission luminance of the light source blocks 1 to 9 that do not correspond to the regions A1 to A9. The light emission rate βn is a value indicating the ratio of the actual light emission luminance of each light source block 1 to the maximum light emission luminance (when white peak is set) of each light source block 1 to 9, and in the range of 0 ≦ βn ≦ 1. Desired.

The light emission rate βn is calculated using the luminance contribution ratios K _{X, Y} (see FIG. 16) of the light source blocks 1 to 9 for the regions A1 to A9. The luminance contribution rate data of the light source blocks 1 to 9 shown in FIG. 16 is stored in advance in the display luminance contribution rate data storage unit 37 as described above, and the stored light source block when calculating the luminous rate βn. Data of luminance contribution ratios 1 to 9 is read out.

In the luminance contribution rate Kx, y, X indicates the regions A1 to A9, and Y indicates the light source blocks 1-9. For example, K _1,1 indicates the luminance contribution ratio of the light source block 1 positioned at the top with respect to the area A1, and for example, K _2,3 indicates the luminance contribution ratio of the light source block 3 positioned at the third position from the top with respect to the area A2. Indicates. As shown in FIG. 16, the luminance contribution rate is not constant in each region for each of the light source blocks 1 to 9, but the display luminance contribution rate data storage unit 37 has a luminance contribution rate Kx, y as, for example, The data at the center of each of the areas A1 to A9 is stored.

  The luminous rate βn is obtained by solving the multiple simultaneous equations (inequality) (2) to (10) shown in FIG.

  In step 1703, the light emission rate βn (0 ≦ βn ≦ 1) is calculated using the multiple simultaneous equations, and the light emission luminances of the light source blocks 1 to 9 are set so as to satisfy the light emission rate βn. A luminance distribution is set.

  The multiple simultaneous equations described above can be used regardless of the configuration of the backlight because the number of n only changes according to the number of divisions of the backlight.

  Moreover, although the example which calculates | requires (beta) n for every light source block 1-9 was shown above, for example, for every primary color of red, green, blue, or every luminescent color of the backlight 12, (beta) n is calculated separately, and brightness | luminance It is also possible to perform control.

  FIG. 19 shows a state in which when a video signal for one field is input, the light emission rate βn is calculated using the above method, and the light emission luminance of each of the light source blocks 1 to 9 of the backlight 12 is controlled. It is an example.

  In FIG. 19, the horizontal axis indicates the position of the display screen in the vertical direction. In FIG. 19, the data of each point connected by a broken line indicates the recovery limit αn in each of the regions A1 to A9, and the data of each point connected by a solid line indicates the light emission rate βn of the light source blocks 1 to 9 in each of the regions A1 to A9. Indicates the total value. That is, the graph of FIG. 19 is a graph representing the above simultaneous equations. Thus, the light emission rate βn is set to a value close to the recovery limit αn, and the light emission luminance of the light source blocks 1 to 9 is efficiently controlled. In this example, the display brightness of the area A5 is the lowest, the display brightness increases as the distance from the area A5 increases, and the display brightness is the highest in the area A1.

  In this way, by using the recovery limit αn and the luminance contribution rate Kx, y, by solving the multiple simultaneous equations, the light emission rate βn of the light source blocks 1 to 9 is obtained and the light emission luminance of each of the light source blocks 1 to 9 is controlled, The light emission luminance of each of the light source blocks 1 to 9 can be suppressed according to the display state of the video. Thereby, the power consumption of the backlight 12 can be reduced. For example, for black parts in the video, the light source block corresponding to the area is turned off, and for bright parts in the video, the light source block corresponding to the area is turned on to display a high contrast video. It becomes possible to do.

  Further, in the present embodiment, since display luminance contribution ratio data indicating how the luminance of one light source block affects the entire display screen is stored, the original image can be faithfully reproduced, High definition image quality can be obtained.

  Further, as described above, the display screen of the liquid crystal display device 11 of FIG. 13 shows an example in which the regions A1 to A9 are divided in the vertical direction for the sake of easy understanding. However, as shown in FIG. 1, the light source blocks 40 are arranged in a matrix on the display screen, the luminance is set for each light source block 40, and the light emission chromaticity is individually set for each light source block 40. It may be driven.

  As described above, after the light emission rate βn is set and the light emission luminance distribution by each of the light source blocks 1 to 9 is set, as shown below, the display luminance of each part of the display screen of the liquid crystal panel 13 is set to the video display. A shift amount correction value for each pixel to obtain an optimum value at the time is calculated. This is the processing of step 1705 described above. This step 1705 may be performed before the above step 1704.

  The deviation amount correction value is calculated based on data on display luminance characteristics of the liquid crystal panel 13 shown in FIG. In FIG. 20, the horizontal axis indicates the set gradation (voltage) S_data of the liquid crystal panel 13 when the output of the backlight 12 is 100% (when the backlight 12 is fully lit), and the vertical axis indicates the liquid crystal panel 13 with respect to the set gradation S_data. Display luminance L_data is shown. Data of the display luminance characteristic f shown in FIG. 20 is obtained in advance and stored in the memory 16, for example.

  For each pixel, γ is the ratio between the display brightness L_peak of all white and the set display brightness L_set. The set display brightness L_set refers to the display brightness when the pixel has a transmittance of 100% when light is emitted from the light source blocks 1 to 9 for which the light emission brightness is set based on the light emission ratio βn.

γ = L_peak / L_set (11)
As described above, the set gradation S_data of the video (original video) displayed when the video signal is input is determined based on the display luminance L_data by the data shown in FIG.

L_data = f (S_data) (12)
The corrected set gradation S_data ′ with respect to the set display brightness L_set is calculated by the following expression based on the ratio γ between the display brightness L_peak of all white and the set display brightness L_set and the set gradation S_data. The correction setting gradation S_data ′ is a shift amount correction value for calculating the transmittance required for each pixel.

S_data ′ = f (γ × L_data) ⁻¹ (13)
By setting the transmissivity of each pixel so that the corrected set gradation S_data ′ is obtained, the original image is reproduced with the optimum display luminance.

  As described above, according to the liquid crystal display device 100 according to the present embodiment, the brightness and chromaticity of each of the light source blocks 1 to 9 are individually controlled, thereby achieving high contrast and high color purity. Video can be faithfully reproduced. Further, the power consumption of the backlight 12 can be reduced.

  The present invention is not limited to the embodiment described above, and various modifications are possible.

  In the form shown in FIG. 17, the backlight lighting control circuit 115 individually sets the light emission chromaticity for each of the light source blocks 1 to 9 in step 1704. However, in the form shown in FIG. 17, the backlight lighting control circuit 115 may be driven so that the chromaticity of the entire display screen is uniform for each field, for example. In other words, in this case, even if the RGB LED elements 31 (R), 31 (G), and 31 (B) constituting the backlight 12 are all set to the same luminance ratio in the light source blocks 1 to 9 and are driven. Good. In this case, when the entire display screen has substantially uniform display chromaticity, the control becomes simpler than when the light source blocks 1 to 9 are individually controlled.

It is a schematic diagram which shows the display apparatus which concerns on one embodiment of this invention. It is a figure which shows an example of the single cell in which each LED element of RGB which comprises a backlight is arranged. It is a figure which shows the equivalent circuit of FIG. It is a schematic diagram which shows arrangement | positioning of a liquid crystal panel and a backlight. It is a block diagram which shows the specific structure of a control part and a backlight lighting control circuit among the liquid crystal display devices shown in FIG. It is a flowchart which shows operation | movement of a liquid crystal display device. It is a figure which shows an example of the image | video for 1 field. (A) is a figure which shows the primary color chromaticity point displayed on a display screen when each LED element of RGB carries out monochromatic light emission, respectively, and it displays with the maximum brightness | luminance gradation by the drive of the liquid crystal panel. (B) is a graph which shows the spectrum of RGB displayed on the display screen at that time. (A) is displayed on the display screen when each of the RGB LED elements emits light with the same luminance (for example, the highest luminance), and a single color is displayed with the highest luminance gradation by driving the liquid crystal panel. It is a figure which shows the primary color chromaticity point to be performed. FIG. 9B is a graph showing the RGB spectrum displayed on the display screen at that time. It is a figure which shows the other example of the image | video for 1 field. 11 is a flowchart illustrating an operation when displaying the video illustrated in FIG. 10. FIG. 12 is a diagram schematically showing the LED elements of the liquid crystal panel 13 and the backlight 42 at this time. It is a figure which shows the structure of the backlight which concerns on other embodiment. It is a block diagram which shows the structure of a control part and memory. It is the figure which showed the example of the light-emitting luminance distribution of each light source block. FIG. 16 shows the luminance contribution ratio of each light source block to each position on the display screen when the emitted light is incident on the liquid crystal panel when each light source block having the light emission luminance shown in FIG. 15 is used. It is a flowchart which shows operation | movement of the liquid crystal display device carrying the backlight shown in FIG. An example of a multiple simultaneous equation for setting the emission luminance distribution will be shown. This is an example showing a state in which when a video signal for one field is input, the light emission rate βn is calculated using the above method, and the light emission luminance of each light source block of the backlight is controlled. It is a graph which shows the display-luminance characteristic with respect to the setting gradation of a liquid crystal panel.

Explanation of symbols

A to T, A1 to A9 ... display screen areas 1 to 9, 40 ... light source block 10 ... liquid crystal display device 12, 42 ... backlight 12 ... or more backlight 13 ... liquid crystal panel 14 ... liquid crystal panel control circuit 15, 115 ... Backlight lighting control circuit 16 ... Memory 19 ... Video signal detection circuit 20 ... Control unit 21 ... Light emission luminance distribution setting unit 25 ... Luminance signal detection circuit 26 ... Color signal detection circuit 28 ... White region 29 ... White region surrounding region 31 ( R), 31 (G), 31 (B) ... LED element 35 ... emission luminance distribution data storage unit 37 ... display luminance contribution ratio data storage unit 38 ... liquid crystal

Claims (7)

A display control device for a display device that displays an image corresponding to an input video signal on a display screen by changing light transmittance for each pixel,
A light source block that emits the light of the three primary colors, and a backlight configured by arranging a plurality of the light source blocks corresponding to a plurality of regions into which the display screen is divided;
Chromaticity signal detection means for detecting a chromaticity signal among the video signals;
A display control apparatus comprising: a luminance ratio control unit that individually controls a luminance ratio of the light of the three primary colors for each of the light source blocks in accordance with the detected chromaticity signal. The display control device according to claim 1,
A display control apparatus, further comprising a transmittance control unit that controls the transmittance of each pixel in accordance with the control by the luminance ratio control unit. The display control device according to claim 2,
The detected chromaticity signal includes a first chromaticity and a second chromaticity different from the first chromaticity in the first area among the areas, and the first area. A second color area displayed continuously with the first color area having the second chromaticity in the first area in the second area adjacent to the second area. If the signal is
The luminance ratio control means includes the first and second luminance ratio control means so that the first color purity displayed in the first color area and the second color purity displayed in the second color area are the same. The display control apparatus according to claim 1, wherein the brightness ratio in each of the second regions is controlled, and the transmittance control unit controls the transmittance of the pixels in the first and second regions. The display control device according to claim 1,
Storage means for storing data of a contribution ratio of display luminance with respect to each area of the display screen when each light source block emits light;
Luminance detection means for detecting a luminance signal among the video signals;
Luminance distribution setting means for setting a light emission luminance distribution of each light source block according to the detected display luminance using the stored contribution rate data;
A display control device further comprising lighting control means for lighting the backlight with the set luminance distribution. The display control device according to claim 4,
When the backlight is turned on by the lighting control unit, the luminance ratio control unit controls the luminance ratio of the light source blocks in the entire area of the display screen to be equal to each other. . A display device that displays an image corresponding to an input video signal on a display screen by changing light transmittance for each pixel;
A light source block that emits the light of the three primary colors, and a backlight configured by arranging a plurality of the light source blocks corresponding to a plurality of regions into which the display screen is divided;
Chromaticity signal detection means for detecting a chromaticity signal among the video signals;
A display device comprising: a luminance ratio control unit that individually controls a luminance ratio of the light of the three primary colors for each of the light source blocks according to the detected chromaticity signal. A display device that displays an image corresponding to an input video signal on a display screen by changing a light transmittance for each pixel; and a light source block that emits the light of the three primary colors. A display control method for a display device comprising a backlight configured by arranging a plurality of the light source blocks corresponding to a plurality of divided areas,
Detecting a chromaticity signal from the video signal;
Individually controlling the luminance ratio of the light of the three primary colors for each of the light source blocks in accordance with the detected chromaticity signal.