| 摘要 |
PURPOSE:To make a device compact by providing an optical member for bending the path of a beam in a light path connecting a light emitting part, a body whose distance is measured and a light receiving part. CONSTITUTION:A spot beam is projected on a body whose distance is measured 9 with an infrared-ray beam projected from a light emitting part 5. The advancing path of the image of the spot beam is bent through a concave lens 11. The image is formed at a light receiving part 7. At this time, the projecting direction of the infrared-ray beam is made to be A. The receiving direction of the spot beam is made to be B'. An angle formed by the directions A and B' is made to be theta2. The infrared- ray beam is temporarily projected on a body whose distance is measured 13 when the body 13 is assumed to be arranged at an actual distance to be measured. Then the image of the spot beam is formed at the light receiving part 7. The receiving direction of the spot beam at this time is made to be B. An angle formed by the directions A and B is made to be theta1. The lens 11 is arranged so that the angle theta1 is equal to the angle theta2. The image of the spot beam from the body 9 can be regarded as the image of the spot beam from the body whose distance is measured 13 which is supposed to be located at the actual distance. In this way, the device can be made compact when the distance is measured. |
