Brightness Adaptive Liquid Crystal Display With Embedded Optical Sensor

In order to avoid visual fatigue caused by the occupants driving in the car,the brightness of the backlight displayed on the vehicle should not be too bright,but it should not be too dark,otherwise it would be difficult for drivers and drivers to recognize the specific content displayed.This requires the use of automatic dimming technology,so that the monitor brightness automatically adjusts to the best state based on ambient light.At present,electronic products use the ambient light sensor based on IC to sense the ambient light intensity.In contrast,a-Si:H TFT with a bottom gate structure of 19000/3.5 um is fabricated on a 8 inch WVGA(800*480)LCD,which is used as optical sensor without additional photolithography mask and processing steps.By designing the peripheral circuit,the drain current is converted into voltage signal.The control unit and LED driver are used to divide the backlight brightness into three modes: daytime,dusk and night.It has been found that the drain current of the a-Si:H TFT sensor is not only controlled by the light intensity,but also influenced by the gate voltage and source-drain voltage.The ambient light sensor based on IC has large range of light and good linearity,but it has defects such as large space occupied in the package,slow response and complex manufacturing process.The a-Si:H TFT sensor manufactured by this paper has a small range of light,but its fast response,high sensitivity in low illumination,easy to manufacture,low cost,save the internal space of the display,reduce the number of components and other advantages.The final experimental results show that the optical sensor embedded in the panel can collect ambient light intensity and achieve automatic dimmingfunction.The brightness adaptive LCD with embedded optical sensor,which is studied in this paper,can not only reduce the power consumption of the LCD,prolong the service life of the battery,but also be suitable for human eyes,improving the comfort of the car environment and the safety of the occupants.