FOREIGN MATTER DETECTION CIRCUIT OF COLOR FILTER

摘要

PURPOSE:To provide a foreign matter detection circuit that detects a foreign matter without missing and outputs the accurate peak value indicating the size thereof. CONSTITUTION:The apparatus consists of a first and a second foreign matter detection sections, a division signal generating circuit that supplies a division signal Ts for dividing each photodetection signal into intervals s and a reference determining circuit that sets a reference value K. Each of the foreign matter detection sections comprises a peak value selection part 61 that selectively outputs a maximum or a minimum peak value from a pattern waveform i of each pixel in the arbitrary divisional interval, a divisional signal hindering part 62 that hinders the divisional signal Ts, a signal detection part 63 wherein the reference value K is subtracted from or added to each of the peak values to form threshold values Ls(n+1) for next interval s(n+1) and the threshold values are compared with photodetection signal of the interval s(n+1) so that a foreign matter detection signal R is outputted therefrom when a foreign matter p is detected and a peak level calculation part 64 that calculates the difference between the photodetection signal and the selected peak level and outputs the difference as peak level data Hp indicating the size of the foreign matter by an foreign matter detection data R.