| 摘要 |
<p>A non-contact, optical distance measuring gauge comprises a single laser (61) light source producing a highly collimated light beam, a beam expander (63) to expand that beam and direct it by way of a 100 % mirror (613) and a 50 % mirror (614) to a divergent diffraction grating (610) to convert the beam into two spaced apart diverging beams. The spaced beams pass through a convergent grating (66) and are directed as converging beams towards a target surface. The convergent grating is patterned or masked to cause each converging beam to illuminate a column or columns of corresponding rectangular areas on the target surface. The illuminated target is viewed by a solid state, array type, video camera (611), a frame of the camera output is digitised and the digitised data processed to determine a mean value of the displacement of the edges of corresponding areas illuminated by the respective beams, to provide a high precision indication of the distance of the target from the gauge.</p> |
