HK1159298A - Image display device and image display method - Google Patents

Description

Image display device and image display method

Technical Field

The present invention relates to an image display device and an image display method for driving a light source that emits light for displaying an image, and an image display device and an image display method for controlling a light source that emits light to a display unit and displaying an image on the display unit.

Background

In a liquid crystal display device, light irradiated from a backlight is transmitted or blocked by a liquid crystal panel, and an image is displayed. The color reproducibility, contrast performance, and power consumption of a liquid crystal display device are mainly controlled by the performance of a liquid crystal panel and a backlight. In recent years, a driving method (hereinafter, referred to as area active driving) has been proposed in which a backlight is divided into a plurality of areas and the light emission ratio of each area is controlled.

In the area active drive, when a part of a displayed image has low luminance, the emission ratio of the area of the backlight corresponding to the part is reduced, and the transmittance of the liquid crystal panel is set in accordance with the emission ratio. In this way, the light emission ratio of the backlight for each region can be optimized, and therefore, the power consumption of the entire backlight can be reduced. In addition, by reducing the light emission ratio for each region, it is possible to reduce the flooding in the liquid crystal display (for example, when the lighting is turned off, a state where black on the screen is inconspicuous and bright), and it is also possible to improve the contrast and the image quality.

In the area active driving, an RGB-LED Light source formed of LEDs (Light-Emitting diodes) of three colors of red (R), green (G), and blue (B) may be used as the backlight. In this case, it is necessary to control not only the light emission ratio for each region but also the LEDs of three colors in the region. Specifically, when a display image corresponding to a certain region is composed of only blue, the red (R) LED (hereinafter, referred to as R-LED) and the green (G) LED (hereinafter, referred to as G-LED) are turned off, and only the blue (B) LED (hereinafter, referred to as B-LED) is turned on, and the transmittance of the liquid crystal display panel is set according to the emission ratio of the B-LED. This makes it possible to display an image having high color purity of only blue. In this way, by controlling only the LEDs necessary for the LEDs located in the region, the effect of reducing power consumption can be made higher than in the case of a white light source. Further, by increasing the color purity of each primary color, the color gamut of the display image can be increased.

In the area active drive as described above, patent document 1 discloses an apparatus and a method capable of controlling local luminance and color characteristics of a backlight. In the device and method disclosed in patent document 1, a liquid crystal display panel is divided into a plurality of regions, and a backlight is configured by a plurality of LEDs for irradiating light to each region. Then, the emission ratios of the LEDs are controlled in accordance with the peak values of the gradations in the respective regions of the liquid crystal display panel.

Patent document 1: japanese patent laid-open No. 2005-338857

Disclosure of Invention

However, in the area active drive using the RGB-LED light source, a problem may occur due to the characteristics of the color filter of the liquid crystal panel. Fig. 9 is a schematic diagram showing a relationship between the transmission characteristics of the color filter of the liquid crystal panel and the wavelengths of the LEDs of RGB. For example, the characteristics of a color filter for blue (B) (hereinafter referred to as B-CF) are present in a portion overlapping with the wavelength of the G-LED. Therefore, even when only the light of the B-LED is transmitted by the B-CF, the light of the G-LED is transmitted by the B-CF, and the excessive light leakage of the LED is generated. When the emission ratios of the respective LEDs are the same and fixed, the ratio of the amount of light transmitted by the B-LED to the amount of light transmitted by the G-LED is generally fixed with respect to the B-CF, and therefore, the amount of light leaked can be prevented by calculating the amount of light leaked from the G-LED with respect to the B-CF at the time of designing.

However, when the emission ratios of the LEDs dynamically change, the amount of light leakage also dynamically changes. Fig. 10 is a schematic diagram for explaining light leakage caused by a change in the light emission ratio. In fig. 10, a green rectangular image 101 is displayed on a blue background image 100 on a screen. The screen is divided into a plurality of regions including a region a and a region B, and the rectangular image 101 is displayed in the region a and is set to be smaller than the region a by one turn. Further, the backlight is divided so as to correspond to each region of the screen, and light emission control can be performed for each region.

In this case, in the region B, since only the background image 100 of blue is displayed, only the B-LED emits light. Therefore, in the region B, light from the region other than the B-LED does not pass through the B-CF, and light leakage does not occur, so that blue with high purity can be displayed. On the other hand, in the area a, since the background image 100 of blue and the rectangular image 101 of green are displayed, both the B-LED and the G-LED emit light. Thus, since light from the G-LED passes through the B-CF, light leakage occurs in the region A. When the amount of light leakage is large, a blue image is displayed with a significantly higher luminance than before. Therefore, on the screen, a phenomenon (hereinafter referred to as a halo phenomenon) occurs in which blue becomes bright due to green light leakage in the outline portion 102 along the outline of the rectangular image 101 and its surroundings (a phenomenon in which a halo is inconspicuously seen in the surroundings), and image quality is impaired. On the other hand, when the halo phenomenon is reduced excessively, the original image color purity is destroyed.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an image display device and an image display method that can reduce light leakage and reduce the possibility of deterioration of image quality.

Another object of the present invention is to provide an image display device and an image display method that can reduce light leakage without deteriorating color purity of an image and reduce the possibility of deteriorating image quality.

An image display device according to the present invention is an image display device that controls emission ratios of light sources of a plurality of colors, which irradiate light to a display unit including a color filter, independently based on a gradation of an image displayed on the display unit, the image display device including: a detection unit that detects luminance or color unevenness generated in the display portion displaying an image and caused by light leakage from a light source other than the light source corresponding to the color filter; an acquisition unit that acquires respective light emission ratios of the light sources; and a control unit that controls the light emission ratios of the light sources so that the colors of light emitted by all the light sources to be synthesized approach white, based on the detection result of the detection unit and the acquisition result of the acquisition unit.

An image display device according to the present invention is an image display device that controls emission ratios of light sources of a plurality of colors, which irradiate light to a display unit including a color filter, independently based on a gradation of an image displayed on the display unit, the image display device including: a detection unit that detects whether or not there is luminance or color unevenness, which is generated in a partial region of the display portion displaying an image and is caused by light leakage from a light source other than the light source corresponding to the color filter, for a plurality of regions; an acquisition unit that acquires respective light emission ratios of the light sources; and a control unit that controls the light emission ratios of the light sources so that the colors of light emitted by all the light sources to be synthesized approach white, based on the number of areas in which luminance unevenness or color unevenness is detected by the detection unit and the acquisition result of the acquisition unit.

The image display device according to the present invention further includes: and a prohibition unit that prohibits the control by the control unit when the detection unit detects that the number of areas in which the luminance is not uniform or the color is not less than a predetermined value.

An image display device according to the present invention is an image display device that controls, for each light source, an emission ratio of a backlight having a plurality of color light sources that irradiate light onto a display unit including a color filter, in accordance with a gradation of an image displayed on the display unit, the image display device including: a detection unit that detects whether or not there is luminance or color unevenness generated in a partial region of the display section displaying an image and caused by light leakage from a light source other than the light source corresponding to the color filter; an acquisition unit that acquires respective light emission ratios of the light sources; and a control unit that controls the light emission ratio of the light source so that the light emission of the light source of the backlight corresponding to the region where the detection unit detects the luminance unevenness or the color unevenness approaches white light, based on the acquisition result of the acquisition unit.

In the image display device according to the present invention, the control means controls the light emission ratio of the light source so that the light emission of the light source approaches white light in a stepwise manner from the periphery of the region detected by the detection means to the region.

In the communication device according to the present invention, the control unit controls the light emission ratio of the light source so that the light from the light source is additively mixed so as to approach white.

In the image display device according to the present invention, the control unit maintains the emission ratio or luminance of the light source having the maximum luminance acquired by the acquisition unit, and controls the emission ratio or luminance of another light source.

In the image display device according to the present invention, the detection means detects luminance unevenness or color unevenness of each frame of the image, and the control means controls the light emission rate of the light source when the detection means detects luminance unevenness or color unevenness of consecutive frames.

In the image display device according to the present invention, the control means may cause the color of the combined light to approach white at a speed obtained based on the detection result of the detection means.

In the image display device according to the present invention, the control means may cause the color of the combined light to approach white at a speed based on the number of regions in which the detection means detects the luminance unevenness or the color unevenness.

In the image display device according to the present invention, the control unit may cause the color synthesized by the light source to approach white in a stepwise manner.

The image display device according to the present invention is characterized in that the image display device further includes a determination unit that determines whether or not to end the control of the control unit based on a detection result of the detection unit when the control unit controls the emission ratio of the light source, and the control unit controls the emission ratio of the light source so that the color of the combined light is separated from white at a speed slower than a speed at which the color of the combined light is brought closer to white when the determination unit determines to end the control of the control unit.

An image display method according to the present invention is an image display method for independently controlling emission ratios of light sources of a plurality of colors, which irradiate light to a display unit including a color filter, based on a gradation of an image displayed on the display unit, the image display method including: detecting luminance or color unevenness which is generated in the display portion displaying an image and is caused by light leakage from a light source other than the light source corresponding to the color filter; a step of acquiring the light emission ratios of the light sources of a plurality of colors, respectively, when the light sources emit light; and a step of controlling the light emission ratio of the light source so that the color of light emitted by the light source to be synthesized approaches white, based on the detected luminance unevenness or color unevenness and the acquired light emission ratio.

An image display method according to the present invention is an image display method for independently controlling emission ratios of light sources of a plurality of colors, which irradiate light to a display unit including a color filter, based on a gradation of an image displayed on the display unit, the method including: detecting whether or not there is luminance or color unevenness, which is generated in a partial region of the display portion in which an image is displayed and is caused by light leakage from a light source other than the light source corresponding to the color filter, in the plurality of regions; a step of obtaining respective light emission ratios of the light sources; and a step of controlling the light emission ratios of the light sources so that the colors of light emitted by all the light sources to be synthesized approach white, based on the number of areas in which luminance unevenness or color unevenness is detected, and the acquired light emission ratios.

An image display method according to the present invention is an image display method for controlling, for each light source, an emission ratio of a backlight having a plurality of color light sources for irradiating light to a display unit including a color filter, in accordance with a gradation of an image displayed on the display unit, the method including: detecting whether or not there is luminance or color unevenness which is generated in a partial region of the display portion displaying an image and is caused by light leakage from a light source other than a light source corresponding to the color filter; a step of obtaining respective light emission ratios of the light sources; and controlling the emission ratios of the light sources based on the acquired emission ratios so that the light sources of the backlight corresponding to the areas where the luminance unevenness or the color unevenness is detected emit light close to white light.

In the present invention, when luminance unevenness or color unevenness occurs in an image displayed on the display unit, the light sources are controlled so that the color of light combined by the plurality of light sources approaches white. When the combined light is made to approach white light, the liquid crystal panel lowers the transmittance to maintain the display color. As a result, it is possible to reduce the possibility that the image quality displayed on the display unit is deteriorated by the transmission of unnecessary light from the light source.

In the present invention, when luminance unevenness or color unevenness occurs in a display portion on which an image is displayed due to light leakage from a light source other than the light source corresponding to the color filter, the light sources are controlled so that the color of light synthesized by the plurality of light sources approaches white. When the combined light is made to approach white light, the liquid crystal panel lowers the transmittance to maintain the display color. As a result, it is possible to reduce the possibility that the quality of an image displayed on the display unit is deteriorated by the transmission of unnecessary light from the light source.

In the present invention, when the luminance unevenness or the color unevenness in the direction of increasing the luminance occurs in the image displayed on the display unit, the light sources are controlled so that the color of the light combined by the plurality of light sources approaches white. Light from the light source passes through the color filter of the display unit, but the color filter has a property of passing only light of a desired wavelength and blocking other light. Therefore, even when the light sources of plural colors emit light, the combined light can be white light, and the white light can be blocked by the color filter. As a result, it is possible to reduce the possibility that the image quality displayed on the display unit is deteriorated by the transmission of unnecessary light from the light source.

Further, by controlling the emission ratio of the light source in accordance with the number of regions in which luminance unevenness or color unevenness is detected, the possibility of damaging the color purity of the display portion can be reduced. For example, when a large number of areas in which luminance unevenness is detected are present, luminance unevenness and color unevenness may occur in most of the display portion. At this time, the viewer may consider the original image to be an image having non-uniform brightness or non-uniform color, and in this case, the viewer may not notice the non-uniform brightness or non-uniform color of the image. Therefore, by not controlling the emission ratio, it is possible to preferentially prevent the color purity from being lowered by controlling the emission ratio.

In the present invention, by making the light emission of the light source approach white light in a stepwise manner, it is possible to reduce a sudden change in light emission at the boundary of a region where luminance unevenness or color unevenness occurs, thereby suppressing the possibility that the viewer feels discomfort.

In the present invention, white can be generated by mixing light of each color in equal amounts using light sources of three colors of Red (Red), Green (Green), and Blue (Blue).

In the present invention, by controlling the emission ratio of the light source to maintain the emission ratio at the maximum, it is possible to eliminate luminance unevenness and color unevenness without reducing the original color purity, and it is possible to reduce the possibility of deteriorating the quality of the displayed image.

In the present invention, when an image composed of a plurality of regions is displayed, if luminance unevenness or color unevenness occurs in a plurality of consecutive frames, the light sources are controlled individually. This reduces the possibility of deterioration in image quality due to deterioration in color purity caused by excessive control of the light source. Note that a frame is an image displayed on one screen, and for example, in a system in which two fields are sequentially displayed, it is an image composed of three fields and obtained by combining colors of R (red), G (green), and B (blue). In addition, the interlaced scanning method refers to an image obtained by combining a scanned image of odd-numbered lines and a scanned image of even-numbered lines, and the non-interlaced scanning method refers to an image displayed by vertical scanning.

In the present invention, the color can be changed according to the content of the image by making the light approach white at a speed based on the result of detecting the luminance unevenness or the color unevenness. For example, when an image in which no brightness unevenness or color unevenness is noticed is displayed and the detected degree is low, the light is made slightly close to white, so that it is possible to prevent a viewer who is viewing the image displayed on the display unit from having a sense of incongruity in which the color changes. In addition, the possibility that the color purity is reduced due to excessive control of the light source, and the image quality is deteriorated can be reduced. In addition, when an image in which unevenness in brightness or unevenness in color is noticeable is displayed, by making light substantially white, the unevenness in brightness or the unevenness in color can be eliminated immediately, and the quality of the image can be prevented from being deteriorated.

In the present invention, the color can be changed according to the content of the image by making the light approach white at a speed based on the result of detecting the luminance unevenness or the color unevenness. For example, when an image in which unevenness in brightness is not noticed is displayed and the detected degree is low, the light is made slightly close to white, so that it is possible to prevent a viewer who is viewing the image displayed on the display unit from having a sense of incongruity in which the color changes. In addition, the possibility that the color purity is reduced due to excessive control of the light source, and the image quality is deteriorated can be reduced. In addition, when an image in which unevenness in brightness or unevenness in color is noticeable is displayed, by making light substantially white, the unevenness in brightness or the unevenness in color can be eliminated immediately, and the quality of the image can be prevented from being deteriorated.

In the present invention, the color of the synthesized light is made to approach white in a stepwise manner, so that the viewer can be prevented from having a sense of incongruity in which the color changes.

In the present invention, when the control of the emission ratio is finished, the light source is controlled so that the synthesized color is separated from white at a slower speed than when changing to white. This prevents the viewer from feeling uncomfortable due to a sudden change in color.

In the present invention, when luminance unevenness or color unevenness occurs in a display portion on which an image is displayed due to light leakage from a light source other than the light source corresponding to the color filter, the light sources are controlled so that the color of light synthesized by the plurality of light sources approaches white. By making the synthesized light approach white light, the transmittance of the display portion can be reduced, and the possibility that the image quality displayed on the display portion is impaired by the transmission of unnecessary light from the light source can be reduced. When the combined light is made to approach white light, the liquid crystal panel lowers the transmittance to maintain the display color. As a result, it is possible to reduce the possibility that the image quality displayed on the display portion is deteriorated by the transmission of unnecessary light from the light source.

Further, by controlling the emission ratio of the light source in accordance with the number of regions in which luminance unevenness or color unevenness is detected, the possibility of damaging the color purity of the display portion can be reduced. For example, when a large number of areas in which luminance unevenness is detected are present, luminance unevenness and color unevenness may occur in most of the display portion. At this time, the viewer may consider the original image to be an image having non-uniform brightness or non-uniform color, and in this case, the viewer may not notice the non-uniform brightness or non-uniform color of the image. Therefore, by not controlling the emission ratio, it is possible to preferentially prevent the color purity from being lowered by controlling the emission ratio.

Drawings

Fig. 1 is a block diagram showing a configuration of a liquid crystal display device according to an embodiment.

Fig. 2 is a diagram schematically showing the structure of the backlight.

Fig. 3A is a schematic diagram showing the emission ratios of the LEDs of the respective colors at different mixing ratios, and shows a case where the mixing ratio is 0.

Fig. 3B is a schematic diagram showing the emission ratios of the LEDs of the respective colors at different mixing ratios, and shows a case where the mixing ratio is 1.

Fig. 3C is a schematic diagram showing the emission ratios of the LEDs of the respective colors at different mixing ratios, and shows a case where the mixing ratio is 0.4.

Fig. 4A is a schematic diagram showing the emission ratios when the emission ratios of the LEDs were changed at a mixing ratio of 33%, and shows the case before the change.

Fig. 4B is a schematic diagram showing the emission ratios when the emission ratios of the LEDs are changed at a mixing ratio of 33%, and shows the changed emission ratios.

Fig. 5A is a graph representing the determined mixing ratio of LEDs in each region within a frame.

Fig. 5B is a graph representing the determined mixing ratio of LEDs in each region within a frame.

Fig. 5C is a graph representing the determined mixing ratio of LEDs in each region within a frame.

Fig. 6 is a flowchart showing processing executed by the control unit and the video processing unit.

Fig. 7A is a diagram showing an example of a pattern in which the halo phenomenon is not reduced.

Fig. 7B is a diagram showing an example of a pattern in which the halo phenomenon is reduced.

Fig. 8 is a flowchart showing processing executed by the control unit and the video processing unit.

Fig. 9 is a schematic diagram showing a relationship between the transmission characteristics of the color filter of the liquid crystal panel and the wavelengths of the LEDs of RGB.

Fig. 10 is a schematic diagram for explaining light leakage caused by a change in the light emission ratio.

Detailed Description

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. The liquid crystal display device according to the present embodiment is an image display device of the present invention, and displays an image based on RGB video signals input from the outside. The RGB video signal may be a signal received by a television wave, a signal read from a recording medium such as a DVD (Digital Versatile Disc), or a signal input via the internet.

[ example 1]

Fig. 1 is a block diagram showing a configuration of a liquid crystal display device according to the present embodiment.

The liquid crystal display device includes a control section 1, a video processing section 2, an area active processing section 3, and a driving section 4 that drives a display panel section 10 and a backlight 11. The display panel section 10 has a backlight 11 disposed on the rear surface side thereof, and a display section for displaying an image based on an input RGB video signal is disposed on the front surface side thereof. The display panel section 10 has display elements having the number of pixels corresponding to the screen display resolution. The display element has a color filter which transmits only a desired light (wavelength) and blocks other light (wavelength), and can transmit light of one of three colors of red (R), green (G), and blue (B). The light is transmitted through the display element, and a color image is displayed on the display portion. The amount of light transmitted through the display element is determined by the transmittance of the display element. The transmittance is a ratio at which the liquid crystal panel can pass light irradiated from the backlight 11.

The backlight 11 is a light source that irradiates light from the back side of the display panel unit 10. Fig. 2 is a diagram schematically showing the structure of the backlight 11. The backlight 11 is divided into a plurality of rectangular regions 110, and each region 110 is provided with an R-LED11a, a G-LED11B, and a B-LED11 c. In each area 110, the backlight 11 is subjected to light emission control. In fig. 2, the region 110 is provided with one LED11a, one LED11b, and one LED11c, respectively, but a plurality of LEDs may be provided. For example, when the amount of light is required, two or more LEDs having the same color may be provided.

The video processing section 2 performs various signal processes on the input RGB video signal. For example, the video processing unit 2 acquires image data (hereinafter, referred to as frames) extracted from an RGB video signal at regular time intervals, acquires the gradation of the image data, adjusts the size of the image data, and the like, and outputs the acquired various information to the control unit 1 and the area active processing unit 3. In addition, the video processing section 2 suitably performs signal processing including: processing for generating RGB signals, digital conversion processing, color space conversion processing, scaling processing, color correction processing, synchronization detection processing, γ correction processing, OSD (On-Screen Display) Display processing, and the like.

The area active processing unit 3 determines the most suitable emission ratios of the LEDs 11a, 11b, and 11c from the peak values of the color components in 1 frame corresponding to the area 110 based on the gradation of the image data input from the video processing unit 2 and the mixing ratio described later input from the control unit 1. For example, when the peak values of the RGB color components in 1 frame are 10% for the red (R), 60% for the green (G), and 30% for the blue (B) components compared to the dynamic range, the area active processing unit 3 sets the emission ratios of the LEDs 11a, 11B, and 11c to 10%, 60%, and 30%, respectively. The area active processing unit 3 determines the light emission ratio for the entire area 110 in units of frames.

Further, the area active processing unit 3 determines a transmittance control value (voltage value) for controlling the transmittance of the display elements of the display panel unit 10 for each frame based on the gradation of the image data and the determined light emission ratio. The area active processing unit 3 outputs the determined light emission ratio and transmittance control value (voltage value) to the control unit 1 and the driving unit 4.

The amount of light transmitted from the display elements of the display panel unit 10 is obtained by multiplying the emission ratios of the LEDs of the colors corresponding to the display elements by the transmittance of the display elements. By determining the light emission ratio and the transmittance control value based on the gradation of the image data, for example, in the case where the gradation of the image data in a certain region of the display panel section 10 is small, the power consumption of the backlight 11 can be reduced by reducing the light emission ratio of the LEDs in the region 110 corresponding to the region.

The driving section 4 includes a panel driving section 41 and a backlight driving section 42. The panel driving unit 41 is a driving circuit of the display panel unit 10, and controls the transmittance of the display elements of the display panel unit 10 by using the transmittance control value input from the area active processing unit 3. The transmittance control value (voltage value) output from the panel driving section 41 charges the electrodes in the display elements of the display panel section 10. The amount of tilt of the liquid crystal in the display element changes with the change in the voltage charged, and as a result, the transmittance of the display element is controlled. The backlight driving section 42 is a driving circuit of the backlight 11, and controls the emission ratios of the LEDs 11a, 11b, and 11c of the backlight 11 based on the emission ratios input from the area active processing section 3. The backlight driving section 42 controls the LEDs 11a, 11b, and 11c in each area 110.

The control Unit 1 is a microcomputer including a CPU (Central Processing Unit) and a ROM (Read Only Memory), and controls each part included in the liquid crystal display device, thereby controlling the entire liquid crystal display device. For example, the control unit 1 acquires a transmittance control value (voltage value) and emission ratios of the LEDs 11a, 11b, and 11c from the area active processing unit 3. The control unit 1 determines the possibility of occurrence of a halo phenomenon (luminance unevenness or color unevenness) in each area 110 based on the information acquired from the video processing unit 2 and the area active processing unit 3. When the halo phenomenon is likely to occur, the control unit 1 changes the mixing ratio in order to reduce the halo phenomenon.

Next, a method of determining whether or not the halo phenomenon occurs will be described.

As described above, the halo phenomenon is a phenomenon in which light from an LED leaks through a filter having a color different from that of the LED, and a halo is invisible in the outline of an image and its surroundings. The control unit 1 detects the occurrence of the halo phenomenon by using the balance of the emission ratios of the LEDs 11a, 11b, and 11c and the balance of the transmittances of the display elements. To explain this specifically, as a premise, in the region a of fig. 10, the emission ratios of the LEDs 11a, 11B, and 11c are set to 0%, 80%, and 20%, in the region B, the emission ratios of the LEDs 11a, 11B, and 11c are set to 0%, and 20%, and the transmittance of the display element is set to 100%. In addition, the light leakage from the G-LED11B for blue (B) was set to 10% of the light leakage from the G-LED11B, and the allowable value of the light leakage was set to less than 20% of the transmission amount for blue (B). The allowable value of the light leakage is a limit value of the amount of light leakage that may deteriorate the image quality.

In this case, since the light emission ratio of the G-LED11b is 80%, the amount of light leakage is 8%. Since the emission ratio of the B-LED11c is 20%, the allowable value of the amount of light leakage is 4%. Since the amount of light leakage of the G-LED11B is 8%, it is larger than the allowable value of the amount of light leakage of the B-LED11 c. That is, in the outline portion 102 and the surroundings thereof, since the light from the G-LED11B is mixed with the light from the B-LED11c, the blue image of the outline portion 102 and the surroundings thereof is displayed in a brighter blue than the original. Therefore, the video processing unit 2 calculates the amount of light leakage, and determines the possibility of occurrence of the halo phenomenon from the calculation result.

The video processing unit 2 determines the possibility of the halo phenomenon in units of one pixel of the display element in each frame. Next, the video processing unit 2 determines pixels adjacent to the pixels in the vertical or horizontal direction in which the halo phenomenon may occur, and detects the continuity of the pixels in which the halo phenomenon may occur. When there is a possibility of occurrence of a halo phenomenon in a plurality of vertical or horizontal pixels, in other words, when there is a possibility of occurrence of a halo phenomenon in a predetermined area (for example, 50% of the area of 1 frame) in 1 frame, the video processing unit 2 determines that there is a possibility of occurrence of a halo phenomenon in the frame. The control unit 1 determines the continuity of the frame in which it is determined that the halo phenomenon is likely to occur, for example, determines that the halo phenomenon is likely to occur in 4 frames in succession, and in this case, determines to execute the process of reducing the halo phenomenon.

In addition, in the present embodiment, only one example of a method of determining the possibility of occurrence of a halo phenomenon is shown, and a method of detecting a halo phenomenon, conditions for determining occurrence of a halo phenomenon, and the like may be changed as appropriate.

Next, a method of reducing the halo phenomenon will be described.

When reducing the halo phenomenon, the area active processing unit 3 causes the synthesized light emitted by the LEDs 11a, 11b, and 11c to approach white light by additive color mixing. Since the light emission ratios of the respective color LEDs of the white light are equal, the area active processing unit 3 controls the light emission ratios of the respective LEDs 11a, 11b, and 11c to be equal so as to approach the white light. In the present embodiment, the LED having the largest emission ratio is not controlled, but is controlled so that the emission ratios of the other LEDs approach the maximum emission ratio. For example, when the emission ratio of the G-LED11B is the maximum, the area active processing unit 3 brings the emission ratios of the R-LED11a and the B-LED11c close to the emission ratio of the G-LED 11B.

The controller 1 determines the mixing ratio so that the combined light emitted by the LEDs 11a, 11b, and 11c approaches white light. The mixing ratio is a ratio when the emission ratios of the LEDs 11a, 11b, and 11c are changed. For example, the emission ratios of the LEDs 11a, 11b, and 11c are determined by the area active processing unit 3, and are optimum for the emission ratios of the color components of the image data, and in this case, the mixing ratio is 0. In other words, when the mixing ratio is 0, the controller 1 does not control the emission ratios of the LEDs 11a, 11b, and 11 c. When the emission ratios of the LEDs 11a, 11b, and 11c are made to match the maximum emission ratio, that is, when the backlight 11 is a white light source, the mixing ratio is 1.

The mixing ratio may be determined according to a prescribed function. For example, when the emission ratios of r1, g1, and b1 are the respective emission ratios of "0", r2, g2, and b2 are the respective emission ratios of the white light source, and m (0. ltoreq. m.ltoreq.1) is the respective emission ratios, rm, gm, and bm obtained from the mixing ratios are as follows.

rm＝(r2-r1)×m+r1

gm＝(g2-g1)×m+g1

bm＝(b2-b1)×m+b1

Fig. 3A is a schematic diagram showing emission ratios of LEDs of respective colors at different mixing ratios, where the mixing ratio is 0, fig. 3B shows a case where the mixing ratio is 1, and fig. 3C shows a case where the mixing ratio is 0.4. When the mixing ratio is 0, the emission ratios of the LEDs 11a, 11b, and 11c are 10%, 60%, and 30% (see fig. 3A). When the mixing ratio is 1, the emission ratios of the LEDs 11a, 11B, and 11c are all 60% (see fig. 3B). When the mixing ratio is 0.4, the emission ratios of the LEDs 11a, 11b, and 11C are 30%, 60%, and 42% (see fig. 3C).

The control unit 1 determines an optimum mixing ratio based on the detection result of the video processing unit 2, and thus reduces the amount of light leakage from the LED of a certain color to be equal to or less than the allowable value of the amount of light leakage from the LEDs of other colors, thereby reducing the halo phenomenon. For example, in the case of using the example of fig. 10, the mixing ratio was determined to be 33%.

Fig. 4A and 4B are schematic diagrams showing the emission ratios when the emission ratios of the LEDs 11a, 11B, and 11c are changed at a mixing ratio of 33%, fig. 4A shows the case before the change, and fig. 4B shows the case after the change. In the case of the region a, the emission ratios of the LEDs 11a, 11B, 11c are 26%, 80%, 40%, and in the case of the region B, the emission ratios of the LEDs 11a, 11B, 11c are 6%, 20%. In this case, the leakage light amount of the G-LED11b having the light emission ratio of 80% was 8%. The light leakage amount of the B-LED11c having the light emission ratio of 40% is 4%, and the allowable value thereof is 8% which is twice the light leakage amount. Since the amount of light leakage of the G-LED11B is 8%, it is equal to or less than the allowable value of the amount of light leakage of the B-LED11 c. As a result, the halo phenomenon occurring in the contour portion 102 and its surroundings can be reduced.

Further, based on the determined mixing ratio, the controller 1 may control only the LEDs 11a, 11b, and 11c included in the region 110 in which the halo phenomenon has occurred, or may control the LEDs 11a, 11b, and 11c of the entire region 110. When only the LEDs 11a, 11b, and 11c of the region 110 in which the halo phenomenon has occurred are controlled, it is possible to prevent the color purity of the display screen corresponding to the region 110 from being lowered by controlling the LEDs 11a, 11b, and 11c of the region 110 in which the halo phenomenon has not occurred. Further, by controlling the emission ratio to be low, power consumption of the backlight 11 can be reduced. On the other hand, in the case of controlling the LEDs 11a, 11b, 11c of the entire area 110, the color purity of the entire screen can be made uniform, and the processing can be simplified, so that the size of the circuit scale can be reduced.

The control unit 1 may change the mixing ratio of the LEDs 11a, 11b, and 11c included in the region where the halo phenomenon occurs and the surroundings thereof. Fig. 5A, 5B, and 5C are graphs showing the mixing ratios of the LEDs 11a, 11B, 11C determined in each area 110 within the frame. Fig. 5 shows the mixing ratios of the LEDs 11a, 11b, and 11c in each of the areas 110 into which the backlight 11 is divided. In fig. 5, a region where a halo phenomenon occurs is referred to as a region 120.

For example, as shown in fig. 5A, when the controller 1 sets the mixing ratio of the LEDs 11a, 11b, and 11c of the region 120 to 1, the mixing ratio of the LEDs 11a, 11b, and 11c of the four regions 110 adjacent to the region 120 in the longitudinal or lateral direction is determined to be 0.5. Then, the control unit 1 determines the mixing ratio of the LEDs 11a, 11b, 11c in the other region 110 to be 0. That is, the mixing ratio of the LEDs 11a, 11b, and 11c is stepwise close to 1 from the region 110 of the mixing ratio 0 to the region 120. This makes it possible to prevent the viewer from feeling discomfort that the emission color of the LEDs 11a, 11b, and 11c changes only around the area 120.

As shown in fig. 5B, when the mixing ratio of the LEDs 11a, 11B, 11c of the area 120 is 0.5, the controller 1 determines the mixing ratio of the LEDs 11a, 11B, 11c of the area 110 adjacent to the area 120 to be 0.25, and determines the mixing ratio of the LEDs 11a, 11B, 11c of the other areas to be 0. Thereby, the mixing ratio of LEDs 11a, 11b, and 11c approaches 0.5 stepwise from region 110 of mixing ratio 0 to region 120.

As shown in fig. 5C, when the mixing ratio of LEDs 11a, 11b, and 11C included in region 120 is 1, controller 1 determines the mixing ratio to be 0.25, 0.5, and 0.75 in order from the region of mixing ratio 0 to region 120. In this case, the color purity can be changed more smoothly than in the case of fig. 5A and 5B.

When changing the determined mixing ratio, controller 1 may cause LEDs 11a, 11b, and 11c to emit light continuously close to white light, or may cause LEDs 11a, 11b, and 11c to emit light in a stepwise manner close to white light. For example, the color purity can be changed smoothly by continuous change, and the color purity can be changed by changing the color purity in a stepwise manner at a time when the viewer is not aware of it, without causing the viewer to feel discomfort. The control unit 1 may also appropriately change the speed of approaching white light. For example, the halo phenomenon may not be noticed by the viewer depending on the location where the halo phenomenon occurs or the size of the generated halo. In this case, the viewer can be prevented from noticing the change in the color of the image displayed on the display panel section 10 by gradually approaching white. In addition, in the case of eliminating the halo phenomenon by approaching white more quickly, an image not spoiling the quality of the image can be displayed.

In the liquid crystal display device having the above-described configuration, an operation when an input RGB video signal is displayed on a screen will be described. Fig. 6 is a flowchart showing the processing executed by the control unit 1 and the video processing unit 2.

The video processing unit 2 acquires RGB video signals inputted from the outside (S1), and acquires the light emission ratios and the transmittance control values of the RGB video signals in 1 frame (S2). The video processing unit 2 acquires the light emission ratio and the transmittance control value determined by the area active processing unit 3, or estimates them in the video processing unit 2. The video processing unit 2 detects whether or not there is a possibility of occurrence of a halo phenomenon in one pixel of the display element (S3), and detects whether or not the number of consecutive pixels in which a halo phenomenon is likely to occur is a predetermined value (S4). Based on the result, it is detected whether or not a halo phenomenon is likely to occur in the frame (S5). Specifically, the video processing unit 2 calculates the amount of light leakage from the LED as described above, and detects whether or not there is a possibility of occurrence of a halo phenomenon based on the calculated result.

The control unit 1 determines whether or not there is a possibility of occurrence of a halo phenomenon in the frame based on the detection result of S5 (S6). In the case where the halo phenomenon is unlikely to occur (S6: NO), the control section 1 ends the processing in the present frame and performs the same processing for the next frame. When the halo phenomenon is likely to occur (YES in S6), the control unit 1 determines whether or not the frame determined to be likely to have the halo phenomenon is 4 or more consecutive frames (S7). When not continuous (S7: NO), the control unit 1 ends the processing in the present frame and performs the same processing for the next frame.

When 4 or more frames are continued (YES in S7), the control unit 1 performs a process of reducing the halo phenomenon (S8). Specifically, the control unit 1 determines an optimum mixing ratio so that the amount of light leakage from the LED of a certain color is reduced to a value equal to or less than an allowable value of the amount of light leakage from the LEDs of other colors, thereby reducing the halo phenomenon. In this case, the controller 1 may control only the LEDs 11a, 11b, and 11c included in the region 110 where the halo phenomenon occurs, or may control the LEDs 11a, 11b, and 11c of the entire region 110. After that, the control unit 1 ends the present process.

Further, when the control unit 1 controls the mixing ratio of the LEDs 11a, 11b, and 11c, the control unit ends the control of the mixing ratio of the LEDs when the possibility of the occurrence of the halo phenomenon disappears. That is, the control unit 1 controls the LEDs 11a, 11b, and 11c that emit light close to white light to emit light far from white light.

As described above, the liquid crystal display device according to the present embodiment determines the possibility of occurrence of the halo phenomenon in frame units with respect to the RGB video signal, and in this case, the light emission of the LEDs 11a, 11b, and 11c is made to be close to white light in a case where frames in which the halo phenomenon is likely to occur are continuous. Accordingly, white light can be blocked by the color filter of the display element, and the amount of light leakage from the backlight 11 can be reduced. As a result, it is possible to reduce the possibility that the image quality displayed on the display panel unit 10 is deteriorated by the transmission of unnecessary light from the backlight 11.

In the present embodiment, when it is determined that there is a possibility of occurrence of a halo phenomenon in 4 consecutive frames, a process of reducing the halo phenomenon is performed, but the number of consecutive frames may be appropriately changed. For example, the consecutive number may be determined according to a time interval of extracting the frame. As described above, only the LEDs 11a, 11b, and 11c of the region 110 where the halo phenomenon occurs may be controlled, or the LEDs 11a, 11b, and 11c of the entire region 110 may be controlled.

Embodiment mode 2

Next, embodiment 2 of the present invention will be explained. In embodiment 1, only whether or not the halo phenomenon is likely to occur is determined, but in the present embodiment, the degree of the likelihood of the halo phenomenon is determined. Then, the speed of controlling the mixing ratio of the LEDs is changed according to the degree thereof. Only the differences will be described below.

The control unit 1 of the liquid crystal display device according to the present embodiment evaluates the possibility of occurrence of the halo phenomenon by dividing into 10 levels based on the amount of light leakage, and changes the mixing ratio of the LEDs 11a, 11b, and 11c at a rate based on the evaluation result. Here, the change in the mixing ratio includes a case where the light emission of the LEDs 11a, 11c, and 11c is made closer to white light, and a case where the light emission of the LEDs 11a, 11c, and 11c is made farther from white light. The case of being far from white light means a case where the mixing ratio of the LEDs 11a, 11b, and 11c is controlled at a certain mixing ratio, and as a result, the halo phenomenon is eliminated (reduced), and thereafter, the mixing ratio is controlled so as to return to (approach) 0. The control unit 1 determines the level according to the amount of leakage light by setting the level to 0 when there is no leakage light and no halo phenomenon, and setting the level to 10 when the amount of leakage light is twice the allowable value of the amount of leakage light, for example.

When the LEDs 11a, 11b, and 11c emit light close to white light, it takes about 60msec for the control unit 1 to shift the level one by one. For example, when the possibility of occurrence of the halo phenomenon is level 4, the control unit 1 takes 240(60 × 4) msec to make the light emission of the LEDs 11a, 11b, and 11c approach white light in order to shift to the control of the mixing ratio determined to reduce the halo phenomenon.

When the LEDs 11a, 11b, and 11c emit light far from white light, it takes about 250msec of time for the control unit 1 to shift the level one by one. For example, when the possibility of occurrence of the halo phenomenon is evaluated as level 4 and then the halo phenomenon disappears (becomes level 0), the control unit 1 takes 1000(250 × 4) msec to separate the light emission of the LEDs 11a, 11b, and 141c from the white light in order to shift to the control of setting the mixing ratio to 0.

By bringing the light emission of the LEDs 11a, 11b, and 11c close to white light in a short time in this way, an image can be displayed without the occurrence of a halo phenomenon being noticed by the viewer. Further, when the image is distant from the white light, the speed is made slower than when the image is close to the white light, and the possibility that the viewer feels discomfort due to a rapid change in the color of the image can be suppressed.

As described above, in the liquid crystal display device according to the present embodiment, when the halo phenomenon occurs, the light emission of the LEDs 11a, 11b, and 11c is brought close to white light in a short time, thereby reducing the halo phenomenon. In the liquid crystal display device, when the halo phenomenon disappears (decreases), the LEDs 11a, 11b, and 11c emit light at a rate slower than the rate of light approaching white light and away from white light.

The speed at which the mixing ratio of the LEDs 11a, 11b, and 11c is changed can be changed as appropriate. For example, when an image is noticed due to a halo phenomenon, the light emission of the LEDs 11a, 11b, and 11c may be made to gradually approach white light. In this case, the viewer is not made to feel uncomfortable with respect to the change in color. When the halo phenomenon occurring in the image is noticed, the light emission of the LEDs 11a, 11b, and 11c is made to quickly approach the white light, whereby the halo phenomenon can be immediately eliminated, and the quality of the image can be prevented from being deteriorated.

Embodiment 3

Next, embodiment 3 of the present invention will be explained. In embodiments 1 and 2, if there is a possibility of occurrence of a halo phenomenon, a process of reducing the halo phenomenon is performed, but the present embodiment differs from embodiments 1 and 2 described above in that the process of reducing the halo phenomenon may not be performed depending on the degree of the possibility of occurrence of the halo phenomenon. Only the differences will be described below.

The video processing unit 2 of the liquid crystal display device according to the present embodiment determines the possibility of occurrence of a halo phenomenon in units of one pixel, and does not perform processing for reducing the halo phenomenon for a frame when it determines that a pixel having the possibility of occurrence of a halo phenomenon occupies an area of, for example, half or more of the area of the frame. In the case where the halo phenomenon occurs in more than half of the area in one frame, the viewer may not notice the occurrence of the halo phenomenon.

Fig. 7A shows an example of a pattern for not reducing the halo phenomenon, and fig. 7B shows an example of a pattern for reducing the halo phenomenon. Fig. 7 shows a case where images of a plurality of leaves are displayed with a blue sky as a background.

For example, the pattern of fig. 7A is displayed on the display panel section 10, and a halo phenomenon occurs in the image of all the blades, and in this case, a halo phenomenon occurs almost in the entire screen. Therefore, the displayed halo phenomenon may be perceived as the original image to the viewer. Therefore, when the halo phenomenon occurs in an area equal to or larger than half of one frame, the control unit 1 does not perform the process of reducing the halo phenomenon. This makes it possible to preferentially display an image of the original color, and thus, the quality of the image can be improved.

On the other hand, when the pattern of fig. 7B is displayed on the display panel unit 10 and the halo phenomenon occurs in the image of all the blades, the halo phenomenon occurs only in a part of the screen. Therefore, the viewer may feel a sense of incongruity with respect to the portion of the halo phenomenon. Therefore, the control unit 1 performs a process of reducing the halo phenomenon when the halo phenomenon occurs in an area equal to or less than half of one frame.

Fig. 8 is a flowchart showing the processing executed by the control unit 1 and the video processing unit 2.

The video processing unit 2 acquires RGB video signals inputted from the outside (S11), and acquires the light emission ratios and the transmittance control values of the RGB video signals in 1 frame (S12). The video processing unit 2 detects whether or not there is a possibility of occurrence of a halo phenomenon in one pixel of the display element (S13), and detects whether or not the number of consecutive pixels in which a halo phenomenon is likely to occur is a predetermined value (S14). Specifically, the video processing unit 2 calculates the amount of light leakage from the LED as described above, and detects the amount based on the calculated result.

The control unit 1 detects a halo phenomenon in the frame (S15), and determines whether or not the halo phenomenon is likely to occur (S16). In the case where the halo phenomenon is unlikely to occur (S16: NO), the control section 1 ends the processing in the present frame and performs the same processing for the next frame. When the halo phenomenon is likely to occur (YES in S16), the control unit 1 determines whether or not the total of all the pixels determined to have the possibility of the halo phenomenon occupies 50% of the area of 1 frame (S17). For example, in a case where a halo phenomenon occurs almost in the entire screen, the viewer may determine that the halo belongs to the original image and thus may not notice the halo phenomenon. On the other hand, when a halo phenomenon occurs in a part of the screen, the viewer may feel a sense of incongruity with respect to the displayed content.

When the total of all the pixels determined to be likely to cause the halo phenomenon does not occupy 50% or less of the area (S17: NO), the control unit 1 determines that the halo phenomenon is not noticed by the viewer because the halo phenomenon is caused in at least half of the screen, and ends the process without performing the process of reducing the halo phenomenon. When the occupied area is 50% or less (YES in S17), the control unit 1 determines that there is a possibility of occurrence of a halo phenomenon in the present frame, and continues to determine whether or not the frame determined to have the possibility of occurrence of a halo phenomenon is 4 consecutive frames (S18).

If the frame is not 4 consecutive frames (S18: NO), the control unit 1 ends the processing in the present frame and performs the same processing for the next frame. Since there is a possibility that the process of reducing the halo phenomenon is not executed depending on the continuity of the frame in which it is determined that the halo phenomenon is likely to occur, the possibility that the quality of the image is deteriorated due to the reduction of the color purity can be reduced by controlling the light source as necessary. If the frame sequence is 4 consecutive frames (YES in S18), the control unit 1 performs a process for reducing the halo phenomenon (S19). Specifically, the control unit 1 determines an optimum mixing ratio so that the amount of light leakage from the LED of a certain color is reduced to a value equal to or less than an allowable value of the amount of light leakage from the LEDs of other colors, thereby reducing the halo phenomenon. In this case, the controller 1 may control only the LEDs 11a, 11b, and 11c included in the region 110 where the halo phenomenon occurs, or may control the LEDs 11a, 11b, and 11c of the entire region 110. After that, the control unit 1 ends the present process.

As described above, the liquid crystal display device according to the present embodiment does not perform the process of reducing the halo phenomenon when the pixels having a possibility of generating the halo phenomenon occupy a predetermined area, and performs the process of reducing the halo phenomenon when the area is equal to or smaller than the predetermined area. Accordingly, even if a halo phenomenon occurs in a complicated pattern, the viewer does not notice the halo phenomenon, and therefore, an image maintaining the original color purity can be displayed without performing a process of reducing the halo phenomenon.

As described in embodiment 1, the control unit 1 may perform the process of reducing the halo phenomenon when the frames to be subjected to the process of reducing the halo phenomenon are consecutive, or may perform the process of reducing the halo phenomenon for each frame. The area occupied by the pixels that are likely to cause the halo phenomenon is set to 50% of the frame, but may be changed as appropriate. For example, when the number of pixels that are likely to cause a halo phenomenon is equal to or greater than a predetermined ratio with respect to the total number of pixels, the process of reducing the halo phenomenon may not be performed.

Although the preferred embodiments of the present invention have been specifically described above, the configuration, operation, and the like of the present invention can be appropriately modified and are not limited to the above embodiments.

Description of the reference symbols

1 control part (detecting unit, control unit, acquiring unit, prohibiting unit)

2 video processing part (control unit, prohibition unit)

3-region active processing unit

4 drive part

10 display panel section

11 backlight source

11a R-LED

11b G-LED

11c B-LED

Claims (15)

1. An image display device that independently controls emission ratios of light sources of a plurality of colors, which irradiate light to a display unit including a color filter, based on a gradation of an image displayed on the display unit, the image display device comprising:

a detection unit that detects luminance or color unevenness generated in the display portion displaying an image and caused by light leakage from a light source other than the light source corresponding to the color filter;

an acquisition unit that acquires respective light emission ratios of the light sources; and

a control unit that controls the light emission ratios of the light sources so that the color of light emitted by all the light sources to be synthesized approaches white, based on the detection result of the detection unit and the acquisition result of the acquisition unit.

2. An image display device that independently controls emission ratios of light sources of a plurality of colors, which irradiate light to a display unit including a color filter, based on a gradation of an image displayed on the display unit, the image display device comprising:

a detection unit that detects whether or not there is luminance or color unevenness, which is generated in a partial region of the display portion displaying an image and is caused by light leakage from a light source other than the light source corresponding to the color filter, for a plurality of regions;

an acquisition unit that acquires respective light emission ratios of the light sources; and

a control unit that controls the light emission ratios of the light sources so that the colors of light emitted by all the light sources to be synthesized approach white, based on the number of areas in which the detection unit detects luminance unevenness or color unevenness, and the acquisition result of the acquisition unit.

3. The image display device according to claim 2, further comprising:

and a prohibition unit that prohibits the control by the control unit when the detection unit detects that the number of areas in which the luminance is not uniform or the color is not less than a predetermined value.

4. An image display device that controls, for each light source, the emission ratio of a backlight having a plurality of colors of light sources that irradiate light onto a display portion including a color filter, in accordance with the gradation of an image displayed on the display portion, the image display device comprising:

a detection unit that detects whether or not there is luminance or color unevenness generated in a partial region of the display section displaying an image and caused by light leakage from a light source other than the light source corresponding to the color filter;

an acquisition unit that acquires respective light emission ratios of the light sources; and

and a control unit that controls the light emission ratio of the light source so that the light emission of the light source of the backlight corresponding to the region where the luminance unevenness or the color unevenness is detected by the detection unit approaches white light, based on the acquisition result of the acquisition unit.

5. The image display apparatus according to claim 4,

the control means controls the light emission ratio of the light source so that the light emission of the light source approaches white light in a stepwise manner from the periphery of the region detected by the detection means to the region.

6. The image display device according to any one of claims 1 to 5,

the control unit controls a light emission ratio of the light source so that light from the light source is additively mixed to be close to white.

7. The image display device according to any one of claims 1 to 6,

the control unit maintains the light emission rate or brightness of the light source with the maximum brightness acquired by the acquisition unit, and controls the light emission rate or brightness of the other light sources.

8. The image display device according to any one of claims 1 to 7,

the detection unit detects luminance unevenness or color unevenness of each frame of the image,

the control unit controls the light emitting rate of the light source under the condition that the detection unit detects that the brightness of the continuous multiframe is not uniform or the color of the continuous multiframe is not uniform.

9. The image display device according to any one of claims 1 to 8,

the control unit makes the color of the synthesized light approach white at a speed obtained based on the detection result of the detection unit.

10. The image display device according to any one of claims 1 to 5,

the control unit makes the color of the synthesized light approach white at a speed based on the number of regions in which the detection unit detects the luminance unevenness or the color unevenness.

11. The image display apparatus according to claim 9 or 10,

the control unit makes the color synthesized by the light source approach white in a stepwise manner.

12. The image display device according to any one of claims 9 to 11,

the image display device further includes a determination unit that determines whether or not to end the control of the control unit based on a detection result of the detection unit when the control unit controls the light emission rate of the light source,

when the determination unit determines that the control by the control unit is to be ended, the control unit controls the light emission ratio of the light source so that the color of the combined light is separated from white at a speed slower than the speed at which the color of the combined light is brought closer to white.

13. An image display method for controlling, independently of each other, the emission ratios of a plurality of color light sources for irradiating light to a display unit including a color filter, based on the gradation of an image displayed on the display unit, the method comprising:

detecting luminance or color unevenness which is generated in the display portion displaying an image and is caused by light leakage from a light source other than the light source corresponding to the color filter;

a step of acquiring the light emission ratios of the light sources of a plurality of colors, respectively, when the light sources emit light; and

and a step of controlling the light emission ratio of the light source so that the color of light emitted by the light source to be synthesized approaches white, based on the detected luminance unevenness or color unevenness and the acquired light emission ratio.

14. An image display method for controlling emission ratios of light sources of a plurality of colors, which irradiate light to a display unit including a color filter, independently based on a gradation of an image displayed on the display unit, the method comprising:

detecting whether or not there is luminance or color unevenness, which is generated in a partial region of the display portion in which an image is displayed and is caused by light leakage from a light source other than the light source corresponding to the color filter, in the plurality of regions;

a step of obtaining respective light emission ratios of the light sources; and

and a step of controlling the light emission ratios of the light sources so that the colors of light emitted by all the light sources to be synthesized approach white, based on the number of areas in which brightness unevenness or color unevenness is detected, and the acquired light emission ratios.

15. An image display method of controlling, for each light source, a light emission ratio of a backlight having a plurality of colors of light sources for irradiating light to a display portion including a color filter, in accordance with a gradation of an image displayed by the display portion, comprising:

detecting whether or not there is luminance or color unevenness which is generated in a partial region of the display portion displaying an image and is caused by light leakage from a light source other than a light source corresponding to the color filter;

a step of obtaining respective light emission ratios of the light sources; and

and controlling the emission ratios of the light sources based on the acquired emission ratios so that the light sources of the backlight corresponding to the areas where the luminance unevenness or the color unevenness is detected emit light close to white light.