| 摘要 |
A method and apparatus for determining the location of a target surface (14) by projecting a periodically scanning pattern of light onto the target surface (14), and comparing the time of projection on a predetermined point of the pattern along a predetermined path within the time of observing an image of the predetermined point of the pattern reflected along an intersecting receiver path. An apertured disc (30) is rotated between a light source (22) and a collimating projection lens assembly (28) to produce a scanning pattern of light. Photoelectric sensors (40, 76) generate reference and receiver electrical signals in response to projection and reception of the pattern of light, and the distance of the target surface from a reference location may be electrically determined as a geometrically defined function of the phase angle between the electrical signals. In one embodiment of the apparatus, the scanning pattern of light is both projected and received through a single projection lens (110), permitting the angular separation between the projection path and the receiver path to be kept small, permitting measurement of a wide range of locations of the target surface within a phase angle variation of less than 360 degrees. |
