| 摘要 |
PURPOSE:To detect a back light state and accurately correct errors in light measurement by using such a photodetector that a peripheral part pattern and a center part pattern which are made of photoconductive materials are connected in series and a common terminal which outputs a back light signal is provided at their connection point. CONSTITUTION:The peripheral part pattern 2 is constituted by charging a photoconductive material continuously in an extremely thin meandering insulation gap formed between an outer peripheral electrode 3 and the common electrode 5 and cross-linking it electrically in parallel. The center part pattern 4 and peripheral part pattern 2 are put as close to each other as possible. Then terminals are provided to the outer peripheral electrode 3, common electrode 5, and center part electrode 6 respectively. Thus, pattern main bodies 2d and 4a are formed meandering, so the probability that spot light at an optical position strikes on the pattern main bodies 2a and 4a is improved to increase photodetection sensitivity, thereby improving the accuracy of back light detection.
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