Patent ID: 6489994
Filing Date: 2002-12-03
Classification: G09G,H04N

Abstract:
A method for adjusting the brightness of a displaying device, the displaying device comprising:an image signal amplifier for amplifying incoming image signals; a cathode ray tube comprising a screen at its front end, an electron gun at its rear end for projecting and controlling an electron beam according to the amplified image signals onto the screen to create an image picture, and an anode for collecting the electron beam emitted onto the screen to produce an anode current; and a brightness control circuit electrically connected to a control end of the image signal amplifier for controlling the amplification magnitude of the image signal amplifier and electrically connected with the anode of the cathode ray tube via a flyback transformer which is used for providing the anode with the anode current wherein when the incoming image signals make the image picture shown on the screen too bright, the anode current of the anode will be increased accordingly, and the brightness control circuit will reduce the amplification magnitude of the image signal amplifier at the same time according to the increase of the anode current so as to reduce the anode current, and wherein the brightness control circuit comprises an adjusting circuit electrically connected with the control end of the image signal amplifier for adjusting the brightness of the image picture of the screen; the method comprising:using a brightness detector to detect the brightness of the image picture of the screen, and using the adjusting circuit to adjust the brightness of the image picture until the brightness detected by the brightness detector reaches a predetermined brightness value.