| 摘要 |
<p>PROBLEM TO BE SOLVED: To quickly and inexpensively inspect whether a foreign objects exists or not on a photo detector with a plurality of light reception parts that are capable of taking out output independently. SOLUTION: Output values V1/S1-V6/S6 being converted per unit area in each of light reception parts 1a-1f are obtained from output values V1-V6 being outputted by applying light L to the entire surface of a photo detector 1 that independently has light reception parts 1a-1f with an area ratio of S1-S6 for outputting an output value by exposure to light, and then the obtained output values are compared, thus detecting whether a foreign object exists or not on the photo detector 1.</p> |
