| 摘要 |
PROBLEM TO BE SOLVED: To provide a photodetector that can correctly adjust a direction of a light receiving element and an emission direction of an emission light depending on the position of a light emitting unit of an opposite party. SOLUTION: In a light receiving/light emitting device that applies emission direction control to a luminous flux depending on positions between a light receiving element and a light emitting element in 2-way communication by the collimated luminous flux with a small diameter, a diffraction lens generates a ± linear diffraction light coaxially and the device receives the lights at a position at which the both lights are overlapped with the same diameter to eliminate a detection error caused by deviation in the luminous intensity distribution in the luminous flux and the vignetting of luminous flux so as to conduct stable attitude control in the 2-way communication. |
