Chromaticity correction device, chromaticity correction method, and display device

1. A chromaticity correction device that corrects chromaticity of a video signal displayed on a display panel of a display device to correspond to a change in a luminance value of the display panel, the chromaticity correction device comprising:

a luminance detection unit configured to detect the luminance value;

a backlight driving level detection unit configured to detect a backlight driving level which is controlling the luminance value;

a temperature detection unit configured to detect an internal device temperature or an ambient temperature corresponding to a temperature of the backlight;

a reference luminance value calculation unit configured to estimate a reference luminance value in a characteristic of an initial state in the backlight driving level and the temperature;

a chromaticity calculation unit configured to obtain a chromaticity change amount of white point chromaticity from the reference luminance value and the luminance value detected by the luminance detection unit and estimated white point chromaticity that is an estimated value of current white point chromaticity from the chromaticity change amount and initial white point chromaticity which is white point chromaticity in the initial state measured in advance;

a chromaticity correction value calculation unit configured to obtain a chromaticity correction value from the estimated white point chromaticity and target white point chromaticity set in advance; and

a chromaticity correction circuit configured to correct the chromaticity of the video signal using the chromaticity correction value.

2. The chromaticity correction device according to claim 1 , wherein:

the reference luminance value calculation unit

includes a conversion expression or a conversion table indicating a correspondence between a luminance value in each combination of a temperature detection value indicating an internal device temperature or an ambient temperature measured in the initial state and the backlight driving level, and a combination of the temperature detection value and the backlight driving level, and

obtains a luminance value corresponding to the backlight driving level detected by the backlight driving level detection unit and the temperature detection value detected by the temperature detection unit using the conversion expression or the conversion table, and uses the luminance value as the reference luminance value.

3. The chromaticity correction device according to claim 2 , wherein:

the chromaticity calculation unit

includes a conversion means indicating a correspondence between a reference luminance ratio and a chromaticity change amount from initial white point chromaticity that is white point chromaticity in an initial state, and

obtains the reference luminance ratio using the luminance value detected by the luminance detection unit and the reference luminance value, determines the chromaticity change amount corresponding to the reference luminance ratio using the conversion means, combines the chromaticity change amount with the initial white point chromaticity stored in advance, and uses a combination result as an estimated white point chromaticity.

4. The chromaticity correction device according to claim 1 , wherein:

the chromaticity correction value calculation unit

includes a conversion means which indicates a correspondence between a result of a comparison of the estimated white point chromaticity and the target white point chromaticity set in advance, and the chromaticity correction value, and

determines the chromaticity correction value corresponding to the comparison result to obtain the color correction value.

5. A liquid crystal display device having a function of correcting chromaticity of a displayed video signal to correspond to a change in a luminance value, the liquid crystal display device comprising:

a luminance detection unit configured to detect the luminance value;

a backlight driving level detection unit configured to detect a backlight driving level which is controlling the luminance value;

a temperature detection unit configured to detect an internal device temperature or an ambient temperature corresponding to a temperature of the backlight;

a reference luminance value calculation unit configured to estimate a reference luminance value which is a luminance value in a characteristic of an initial state in the backlight driving level and the temperature detection value;

a chromaticity calculation unit configured to obtain a chromaticity change amount of white point chromaticity from the reference luminance value and the luminance value detected by the luminance detection unit and estimated white point chromaticity that is an estimated value of current white point chromaticity from the chromaticity change amount and initial white point chromaticity which is white point chromaticity in the initial state measured in advance;

a chromaticity correction value calculation unit configured to obtain a chromaticity correction value from the estimated white point chromaticity and target white point chromaticity set in advance;

a chromaticity correction circuit configured to correct the chromaticity of the video signal using the chromaticity correction value; and

a display unit configured to display the corrected video signal output from the color correction circuit.

6. A chromaticity correction method for controlling a chromaticity correction device which corrects chromaticity of a video signal displayed on a display panel of a display device to correspond to a change in a luminance value of the display panel, the chromaticity correction method comprising:

detecting the luminance value for a luminance detection process;

detecting a backlight driving level which is controlling the luminance value for a backlight driving level detection process;

detecting an internal device temperature or an ambient temperature corresponding to a temperature of the backlight for a temperature detection process;

estimating a reference luminance value which is a luminance value in a characteristic of an initial state in the backlight driving level and the temperature for a reference luminance value calculation process;

obtaining a chromaticity change amount of white point chromaticity from the reference luminance value and the luminance value detected by the luminance detection process, and obtaining estimated white point chromaticity that is an estimated value of current white point chromaticity from the chromaticity change amount and initial white point chromaticity which is white point chromaticity in the initial state measured in advance for a chromaticity calculation process;

obtaining a chromaticity correction value from the estimated white point chromaticity and target white point chromaticity set in advance for a chromaticity correction value calculation process; and

correcting the chromaticity of the video signal using the chromaticity correction value for a chromaticity correction process.