| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a photodetector module having such characteristics that noise caused by refection of signal light inside a photodetector module is reduced, and that a reduction in light sensitivity in a photodetector module is restricted. <P>SOLUTION: The photodetector module includes an optical member which emits the signal light input from the outside to the inside of the module, a lens which converts the outgoing light emitted from the optical member into convergent light before being emitted, and a reflection surface 21 which is disposed in such a way that its normal direction is oblique relative to the optical axis of the convergent light, and also includes a light receiving element 4 which receives the convergent light and converts the received light into an electric signal. The numerical aperture of a reflected light 12 derived from the convergent light by reflection at the reflection surface has an anisotropic distribution with respect to the optical axis of the reflected light on a reflected light perpendicular plane which intersects the optical axis of the reflected light at right angles, where a second direction having a larger numerical aperture than the numerical aperture of the reflected light in a first direction, or a direction such that the direction of a normal line extending from the reflection surface is orthogonally projected on the reflected light perpendicular plane, exists on the reflected light perpendicular plane in a different direction that the first direction. <P>COPYRIGHT: (C)2012,JPO&INPIT |
