Angle detecting device and optical apparatus, such as exposure apparatus, employing the same.

摘要

Disclosed is a device for determining an angle of incident light or a shift in incident light based on the output value of a detector. In a predetermined angle detection range, a beam of light incident on a detector for detecting the intensity of light incident thereon is restricted such that the amount of light continuously increases or decreases in accordance with the angle between an optical axis of the incident light and a referential axis of an exposure apparatus. Outside of the predetermined angle detection range, the amount of light is restricted depending on the direction in which the optical axis of the light is shifted from the angle detection range. The amount of light incident on the detector continuously increases or decreases in accordance with the angle between the optical axis of the incident light and the referential axis when the light is made incident within the angle detection range by means of the light restriction means. It is therefore possible to determine the angle of the incident light from the output value of the detector. When the light is made incident outside of the angle detection range, and since the amount of incident light is restricted in accordance with the direction in which the light is shifted, it is possible to determine the direction in which the light is shifted. <IMAGE>