PICTURE INFORMATION READER

摘要

PURPOSE:To correct easily the variance of light quantity of a light source by using the output of a photodetecting element receiving a part of a laser as a control signal of a photoelectric conversion system for received light. CONSTITUTION:The laser light which is partially divided before deflection by a beam splitter 9 set between a laser 1 and a polygon mirror 2 is converted into a current signal corresponding to the incident light by a photodetecting element 10. This current signal is amplified by a current amplifier 11 and then supplied to a logarithm converter 7 as a reference signal. This reference signal changes the conversion range of the converter 7. Then the converter 7 delivers a picture signal which has undergone correction for variation of the light quantity.