LIGHT RECEIVING DEVICE, SHIELDING PLATE, PASSAGE ASSISTING PROGRAM, PASSAGE ASSISTING METHOD AND PASSAGE ASSISTING DEVICE

摘要

The most suitable boundary position is set up with a less expensive and simple structure, so that a high precision position location is realized to promote the effective use of existing facilities. A shielding plate (402) shields a part of a light signal with an incident angle on a light receiving unit (401) that is not less than (a1) but less than (a2), all the light signal with the incident angle on the light receiving unit (401) that is not less than (a2), a part of the light signal with the incident angle on the light receiving unit (401) that is not less than (ß1) but less than (ß2), and all the light signal with the incident angle on the light receiving unit (401) that is not less than (ß2), so that a light receiving device (300) can precisely detect a boundary position where it comes not to receive the light signal.