| 摘要 |
PURPOSE:To reduce the change of a detecting distance, by bringing the angle formed by the optical axis of one of a light emitting element and a light receiving element and the center line crossing the center point of a line connecting both elements at right angles to a specific range when the angle formed by the aforementioned center line and the optical axis of the other element is set to -theta. CONSTITUTION:When the center line crossing the center point of a straight line connecting a light emitting element T and a light receiving element R at right angles is set to CT, an approaching matter detecting apparatus is constituted so that the angle -theta formed by the optical axis O' of the light emitting element T and the center line CT comes to the incident angle to matter. In this case, the angle (light receiving angle) formed by the optical axis O' and the center line CT is set to a range of theta-20 deg.-theta-10 deg. or theta+10 deg.-theta+20 deg.. By this constitution, an error generated by the characteristics (shape, color and material quality) of the approaching objective matter from the aspect of a detecting distance can be made small as possible. |
