| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent errors from being generated in detected data by making variable the radius of a pin hole to a change in the quantity of light, and to prevent an error in data due to the change in the quantity of light from being generated by setting the radius of the pin hole at the value of a=√(1/b) in the state corresponding to a change b-times as much as the quantity of light from the normal quantity of light. SOLUTION: A substrate position detecting device is constituted in a structure that a sensor 6 consisting of a light-projecting part 4 and a light-receiving part 5 is provided at positions opposing to each other holding a substrate housing container 2 between them, and a variable pin hole 3 is mounted in a sensor mounting stand. When the sensor 6 is moved relatively to the container 6 and the position of a substrate 1 is detected, the optical axis of light irradiated from the part 4 passes through the pin hole 3 to contrive to propagate in the light-receiving part 5. By changing the size of the pin hole 3 to a change in the quantity of light which is propagated in the part 5, the position of the substrate 1 is accurately detected.</p> |
