Patent ID: 6313586
Filing Date: 2001-11-06
Classification: H04N,H05B

Abstract:
A light source control apparatus for use in an image input apparatus comprising a cold cathode tube light source and a solid imaging device, said image input apparatus reading an image from a document paper by receiving at said solid imaging device a reflected light which is obtained by reflecting a light of said cold cathode light source on said document paper, wherein said light source control apparatus comprises:a feedback circuit that provides an output of said solid imaging device as a feedback signal; anda current control circuit that regulates a tube current applied to said cold cathode tube light source responsive to said feedback signal, said control circuit being operative to supply current to said cold cathode tube light source at an overcurrent level higher than a predetermined tube current immediately upon said cold cathode tube light source being placed into an on-state without significant time delay, and thereafter at a level responsive to said feedback signal for continuously and stably irradiating said cold cathode tube light source at a predetermined luminous energy.