| 摘要 |
PURPOSE:To widen a distance measuring range by providing three light receiving means in a light illumination type triangular distance measuring system. CONSTITUTION:Infrared rays from a distance measuring use light emitting element 11 pass through a projecting lens 13 and are projected to an object 16. Reflected light beams from the object 16 transmit through a light receiving lens 14 and harmful light beams cut filter 15 which have been placed at a distance of base line length (d) from an optical axis of a projection system and made incident on three light receiving element 12a-12c which have been placed in parallel. When an output of the light receiving element 12a is larger than an output of the element 12c (when a distance to the object 16 is farther than R1), the distance to the object 16 is operated from an output ratio of the element 12a and 12b, and in case or the contrary, the distance to the object 16 is operated from an output ratio of the element 12b and 12c. As a result, a distance measurement can be executed automatically extending over a wide range without providing a mechanical operating part. |
