Patent ID: 9706182
Date: 2017-07-11
CPC Classifications: H04N

Claim:
1. A projection apparatus comprising: a light valve reflecting an illumination beam and converting the illumination beam into an image beam; a lens arranged on a transmission path of the image beam, so as to project the image beam onto a screen and display a screen image on the screen; a temperature sensing unit sensing a temperature of the light valve and generating a temperature sensing signal; and a control unit coupled to the temperature sensing unit and the light valve, the control unit adjusting a grayscale characteristic of the light valve according to the temperature sensing signal, so as to improve a contrast and grayscale accuracy of the screen image, wherein the control unit comprises: a storage unit storing a grayscale characteristic curve lookup table; and a micro controller unit coupled to the storage unit, the temperature sensing unit, and the light valve, the micro controller unit looking up the grayscale characteristic curve lookup table according to the temperature sensing signal to find a grayscale characteristic curve corresponding to the temperature sensing signal and controlling the light valve to reflect the illumination beam according to the grayscale characteristic curve corresponding to the temperature sensing signal.