| 摘要 |
PROBLEM TO BE SOLVED: To provide a light detection mechanism and the like that have a small and simple configuration and are capable of detecting the tilt deviation and shift deviation of light emitted by a light source.SOLUTION: A light detection mechanism 100 has a light receiving surface 103a for receiving laser light emitted by a light source, and comprises: a light detector 103 for outputting a detection signal corresponding to the laser light received at the light receiving surface 103a; a convex lens 102 for collecting light by letting the laser light pass through; a polarization beam splitter 104 and shutters 108, 109 as focus position change means for switching between a first state of letting the laser light that has passed through the convex lens 102 input into the light receiving surface 103a in the state of focusing on the light receiving surface 103a, and a second state of letting the laser light that has passed through the convex lens 102 input into the light receiving surface 103a in the state of not focusing on the light receiving surface 103a; and a shutter driving unit 110 for driving those.SELECTED DRAWING: Figure 1A |
