Patent ID: 7379174

Claim:
A detecting device for detecting a storage state of a substrate of a light transmission type in a predetermined position in a substrate processing apparatus using the substrate, comprising: a light reflection sensor including a light emitting portion and a light receiving portion; and a light transmission sensor including a light emitting portion and a light receiving portion, wherein the light receiving portion of the light reflection sensor, the light emitting portion thereof, and the light receiving portion of the light transmission sensor are disposed on one surface side of the substrate to be detected in a position in which the substrate is located, and the light emitting portion of the light transmission sensor is disposed on the other surface side of the substrate to be detected in the position in which the substrate is located, and wherein the light receiving portion of the light reflection sensor uses inside surface reflection light which is caused in the inside of the substrate to be detected, and a sensor light emitted from the light emitting portion of the light reflection sensor is set such that an emission area of the sensor light on the substrate becomes larger than an emission area of the sensor light when the sensor light is emitted from the light emitting portion of the light reflection sensor.