Display device and display method
View Patent ↗Disclosed is a display device capable of compensating unevenness in brightness caused by physical restrictions of a display device or degradation in image quality caused by a partial reduction in contrast occurring in the local dimming technology using human visual characteristics. A liquid crystal panel ( 101 ) modulates illuminating light in accordance with the transmittance, and displays images on a screen. A backlight ( 102 ) emits the illuminating light to the liquid crystal panel ( 101 ) such that amounts of the illuminating light differ for each light emitting area of the screen. A backlight control unit ( 106 ) controls emission brightness of the backlight ( 102 ) for each light emitting area. A local gradation converting unit ( 104 ) performs gradation conversion on an image signal, and acquires a brightness value for each pixel after the conversion. A backlight driving unit ( 107 ) controls the transmittance for each pixel on the basis of the acquired brightness values after the conversion. The local gradation converting unit sets conversion characteristics for pixels to be processed in the image signal such that the brightness values of the pixels to be processed are low as the lightness of the periphery of the pixels to be processed is high, and performs gradation conversion using the set conversion characteristics.
1. A display apparatus comprising:
a light modulating section which modulates illumination light according to a light modulation coefficient and displays an image on a screen;
a radiating section which radiates the illumination light on the light modulating section with an illumination light amount which varies per light emitting area of the screen;
a control section that receives a video signal and which controls light emission brightness of the radiating section per light emitting area based on a control signal output by the control section;
a video correcting section which corrects the video signal based on a light amount of illumination light which arrives at the light modulating section;
a converting section separate from the control section and that receives the video signal and which applies individual gradation conversion processing on each pixel of the video signal and acquires a converted brightness value per pixel; and
a first driving section which controls the light modulation coefficient per pixel based on the acquired converted brightness value,
the control signal output by the control section is not input into the converting section,
wherein for each processing target pixel in the video signal, the converting section sets conversion characteristics of decreasing a brightness value of each processing target pixel when a luminosity in a surrounding area of each processing target pixel is higher, the surrounding area being a part of area in the video signal, and performs gradation conversion using the set conversion characteristics.
2. The display apparatus according to claim 1 , wherein the converting section detects average luminosity in the surrounding area of each processing target pixel as the luminosity in the surrounding area of each processing target pixel.
3. The display apparatus according to claim 1 , wherein the conversion characteristics include characteristics of making no change of a brightness value equal to the luminosity in the surrounding area of each processing target pixel.
4. The display apparatus according to claim 1 , wherein the conversion characteristics include characteristics of increasing a brightness value of a halftone.
5. The display apparatus according to claim 1 , wherein the control section controls light emission brightness of the radiating section per light emitting area based on the acquired converted brightness value.
6. The display apparatus according to claim 1 , wherein the converting section performs gradation conversion to decrease a brightness value of a processing target pixel positioned near a pixel where the light modulation coefficient is a maximum value in a range which can be realized by the light modulating section.
7. The display apparatus according to claim 1 , wherein the converting section performs gradation conversion to increase a brightness value of a processing target pixel positioned near a pixel where the light modulation coefficient is a minimum value in a range which can be realized by the light modulating section.
8. A display apparatus comprising:
a light modulating section which modulates illumination light according to a light modulation coefficient and displays an image on a screen;
a radiating section which radiates the illumination light on the light modulating section with an illumination light amount which varies per light emitting area of the screen;
a control section that receives a video signal and which controls light emission brightness of the radiating section per light emitting area based on a control signal output by the control section;
a video correcting section which corrects the video signal based on a light amount of illumination light which arrives at the light modulating section;
a converting section separate from the control section and that receives the video signal and which applies individual gradation conversion processing on each pixel of the video signal and acquires a converted brightness value per pixel; and
a first driving section which controls the light modulation coefficient per pixel based on the acquired converted brightness value,
the control signal output by the control section is not input into the converting section,
wherein for each processing target pixel in the video signal, the converting section performs gradation conversion of enhancing local contrast using conversion characteristics of decreasing a brightness value of each processing target pixel when a luminosity in a surrounding area of each processing target pixel is higher, the surrounding area being a part of area in the video signal.
9. A display method comprising:
a light modulating step of modulating illumination light according to a light modulation coefficient and displaying an image on a screen;
a radiating step of radiating the illumination light on a light modulating section with an illumination light amount which varies per light emitting area of the screen;
a control step of receiving a video signal and controlling a light emission brightness in the radiating section per light emitting area based on a control signal;
a video correcting step of correcting the video signal based on a light amount of illumination light which arrives at the light modulating section;
a converting step, separate from the control step, of receiving the video signal and applying individual gradation conversion processing on each pixel of the video signal and acquiring a converted brightness value per pixel; and
a first driving step of controlling the light modulation coefficient per pixel based on the acquired converted brightness value,
the control signal is not used in the converting step to acquire the converted brightness value,
wherein for each processing target pixel in the video signal, the converting step performs gradation conversion of enhancing local contrast using conversion characteristics of decreasing a brightness value of each processing target pixel when a luminosity in a surrounding area of each processing target pixel is higher, the surrounding area being a part of area in the video signal.
10. A display method comprising:
a light modulating step of modulating illumination light according to a light modulation coefficient and displaying an image on a screen;
a radiating step of radiating the illumination light on a light modulating section with an illumination light amount which varies per light emitting area of the screen;
a control step of receiving a video signal and controlling a light emission brightness in the radiating section per light emitting area based on a control signal;
a video correcting step of correcting the video signal based on a light amount of illumination light which arrives at the light modulating section;
a converting step, separate from the control step, of receiving the video signal and applying individual gradation conversion processing on each pixel of the video signal and acquiring a converted brightness value per pixel; and
a first driving step of controlling the light modulation coefficient per pixel based on the acquired converted brightness value,
the control signal is not used in the converting step to acquire the converted brightness value,
wherein for each processing target pixel in the video signal, the converting step performs gradation conversion of enhancing local contrast using conversion characteristics of decreasing a brightness value of each processing target pixel when a luminosity in a surrounding area of each processing target pixel is higher, the surrounding area being a part of area in the video signal.
11. The display apparatus according to claim 1 , further comprising a second driving section that receives the control signal output from the control section and that controls the light emission brightness of the radiating section per light emitting area.
12. The display apparatus of claim 8 , further comprising a second driving section that receives the control signal output from the control section and that controls the light emission brightness of the radiating section per light emitting area.
13. The display method of claim 9 , further comprising a second driving step of receiving the control signal and controlling the light emission brightness in the radiating section per light emitting area based on the control signal.
14. The display method of claim 10 , further comprising a second driving step of receiving the control signal and controlling the light emission brightness in the radiating section per light emitting area based on the control signal.