| 摘要 |
<p>PURPOSE:To permit exact correction for varying temperatures all the time by providing a monitoring circuit by which light amount of a semiconductor light source is measured and converted into voltage signals and a correcting circuit by which deviations obtained from comparison with reference voltage are given to image signals. CONSTITUTION:An image signal VI is given to luminous elements 3R-3B through an arithmetic amplifier 10, a voltage-current converter 11, a luminous diode 12, a photo diode 13, an amplifier 14, a three-color converter circuit 15, and amplifier 17 (17R-17B). The signal VI is then put in a monitor light receiving element 6 in a contactless manner. A arithmetic loop is formed in which the deviations between the output of a monitor light receiving diode and reference voltages KR, KG and KB are received by differential amplifiers 22R, 22G and 22B and put in the arithmetic amplifier 10 for adding or subtracting calculation. Since voltage for controlling light amount of luminous diode corresponding to DELTAt deg.C is always added to normal signal VI by the arithmetic amplifier 10. A photo-sensitive material is exposed to light after temperature correction all the time.</p> |
