A beam current detection unit (5) detects the brightness of the image displayed on a screen (10) on the basis of a current J flowing inside a CRT (1). A drive control unit (40) selectively closes and opens the switches (42) and (43) in accordance with the detected brightness. Restriction characteristic...http://www.google.com/patents/US20020109789?utm_source=gb-gplus-sharePatent US20020109789 - Image display device with controlled image quality
