Display device and method of controlling its brightness

Abstract

A temperature difference estimated value is found from a video signal using a temperature estimated value representing the temperature of the panel outer periphery of a display screen of a PDP and a reference value representing the temperature of the panel outer periphery of the PDP which is outputted from a panel periphery temperature setter by a temperature difference estimator, and the luminance of an image displayed on a display is controlled depending on the temperature difference estimated value by a controller and a brightness controller.

1. A display device, comprising:
 a display having a display screen that displays an image with a luminance corresponding to a video signal, and an outer peripheral portion adjacent to said display screen;  
 a temperature estimation device that estimates, from said video signal, a temperature value corresponding to a display screen temperature;  
 an operation device that determines a temperature difference estimate value in accordance with a reference value corresponding to a temperature of said outer peripheral portion and said estimated temperature value; and  
 a control device that lowers the luminance of the image as said temperature difference estimate value increases.  
 
     
     
       2. The display device of  claim 1 , wherein said temperature estimation device estimates said temperature value in accordance with the temperature of an outer periphery adjacent portion of said display screen adjacent to said peripheral portion. 
     
     
       3. The display device of  claim 1 , wherein said display comprises:
 a first board and a second board whose outer peripheries are joined to each other, a plurality of light emitting elements that form said display screen being interposed between said first board and said second board, and wherein said outer peripheral portion of said display includes a portion between said plurality of light emitting elements positioned in an outermost periphery of said display screen and a joint portion of said first board and said second board.  
 
     
     
       4. The display device of  claim 1 , wherein said temperature estimation device integrates data related to said luminance from said video signal and subtracts data corresponding to an amount of dissipated heat from said integrated data, said operation device determining said temperature difference estimate value by subtracting said reference value from said estimated temperature value. 
     
     
       5. The display device of  claim 1 , wherein said display screen displays the image on a gray scale, out of a plurality of gray scales, related to said video signal, and wherein said control device lowers the luminance of the image by a same ratio for each of said plurality of gray scales. 
     
     
       6. The display device of  claim 1 , wherein said reference value comprises a plurality of reference values that differ depending on a position of said outer peripheral portion of said display. 
     
     
       7. The display device of  claim 1 , further comprising:
 a measurement device that measures a temperature of said outer peripheral portion of said display, said measurement device outputting a reference value, corresponding to said measured temperature, to said operation device.  
 
     
     
       8. A method for controlling a luminance of a display, in which a display screen displays an image having a predetermined luminance corresponding to a video signal, an outer peripheral portion being adjacent to said display screen, the method comprising:
 estimating a temperature value corresponding to a temperature of the display screen from the video signal;  
 estimating a temperature difference value using a reference value that corresponds to a temperature of the outer peripheral portion and the estimated temperature value; and  
 lowering the luminance of the image as the estimated temperature difference value increases.  
 
     
     
       9. A display device, comprising:
   a display having a display screen that displays an image with a luminance corresponding to a video signal, and an outer peripheral portion adjacent to said display screen;        a temperature estimation device that estimates, from said video signal, a temperature value corresponding to a display screen temperature;        an operation device that determines a temperature difference estimate value in accordance with a reference value corresponding to a temperature of said outer peripheral portion and said estimated temperature value; and        a control device that controls the luminance of the image based on the temperature difference estimation value.