Liquid crystal display with photodetectors having polarizing plates mounted thereon and its correcting method

Abstract

The quantity of light from a backlight is monitored by a first photodetector, and the environment on the part of a user is monitored by a second photodetector disposed in the rear of a liquid crystal panel, not on the front thereof. It is possible to exclude the influence of external light from the user side on the first photodetector which detects the quantity of light from the backlight.

1 - 2 . (canceled)  
   
   
       3 . A liquid crystal display wherein an image sensor is disposed behind a liquid crystal panel and directed toward the display screen to capture image or illuminance information in the direction of the display screen when liquid crystal is made to transmit therethrough light.  
   
   
       4 . A liquid crystal display wherein an image sensor is disposed behind a liquid crystal panel and directed toward the display screen to capture image or illuminance information in the direction of the display screen when liquid crystal is made to transmit therethrough light, the image sensor having mounted thereon a polarizing plate whose direction of polarization is identical with that of a polarizing plate on the side of a backlight with respect to liquid crystal.  
   
   
       5 . (canceled)  
   
   
       6 . A calibration method for the liquid crystal display recited in  claim 3 , characterized in that: a second light source and a second photodetector are disposed behind the liquid crystal panel and on the display screen of the liquid crystal panel, respectively; when a calibrating image signal is input to the liquid crystal display, said second light source is modulated; light transmitted through liquid crystal is detected by the second photodetector; the modulated signal is demodulated to obtain the optical transfer characteristic of the liquid crystal; and a conversion function or conversion table of the calibrating image signal is obtained for calibration of the image display.  
   
   
       7 . A calibration method for the liquid crystal display recited in  claim 3 , characterized in that: a third light source formed by a light emitting diode or semiconductor laser is disposed on the display screen of the liquid crystal panel and directed toward the display screen, the light emitting diode or semiconductor laser emitting light polarized in the same direction as the direction of polarization of the liquid crystal panel; when a calibrating image signal is input to the liquid crystal display, the light source is modulated; the modulated signal detected by a photodetector or image sensor disposed behind the liquid crystal panel is demodulated to obtain the optical transfer characteristic of the liquid crystal; and a conversion function or conversion table of the calibrating image signal is obtained for calibration of the image display.  
   
   
       8 . A calibration method for the liquid crystal display recited in  claim 4 , characterized in that: a second light source and a second photodetector are disposed behind the liquid crystal panel and on the display screen of the liquid crystal panel, respectively; when a calibrating image signal is input to the liquid crystal display, said second light source is modulated; light transmitted through liquid crystal is detected by the second photodetector; the modulated signal is demodulated to obtain the optical transfer characteristic of the liquid crystal; and a conversion function or conversion table of the calibrating image signal is obtained for calibration of the image display.  
   
   
       9 . A calibration method for the liquid crystal display recited in  claim 4 , characterized in that: a third light source formed by a light emitting diode or semiconductor laser is disposed on the display screen of the liquid crystal panel and directed toward the display screen, the light emitting diode or semiconductor laser emitting light polarized in the same direction as the direction of polarization of the liquid crystal panel; when a calibrating image signal is input to the liquid crystal display, the light source is modulated; the modulated signal detected by a photodetector or image sensor disposed behind the liquid crystal panel is demodulated to obtain the optical transfer characteristic of the liquid crystal; and a conversion function or conversion table of the calibrating image signal is obtained for calibration of the image display.  
   
   
       10 . A liquid crystal display comprising: a liquid crystal panel having a liquid crystal, an image sensor that is disposed behind the liquid crystal panel and directed toward the liquid crystal panel to capture image or illuminance information when the liquid crystal is made to transmit a light, and a backlight that is disposed behind the liquid crystal panel, 
 wherein the liquid crystal is interposed between first polarizing plates, a second polarizing plate is mounted on the image sensor, a change of a direction of polarization of the first polarizing plates with respect to the second polarizing plate is possible.