Patent ID: 6473189
Filing Date: 2002-10-29
Classification: G01B,G01S

Abstract:
An apparatus for measuring a distance to a reflective surface when the reflective surface is located between a first and second predetermined positions along a common axis, the apparatus operable to measure the distance when the reflective surface is at an angle other than 0 degrees with respect to a plane normal to the common axis, comprising:a first light source operable to transmit a first light onto the reflective surface, the reflective surface reflecting at least a portion of the light, the first light source located on a first side of the axis; a first light-detecting device having a first region operable to receive the reflected first light from the reflective surface and to transmit a first and second signals as a function of the location of the received first light within the first region; a second light source operable to transmit a second light onto the reflective surface, the reflective surface reflecting at least a portion of the second light, the second light source located on a second side of the axis; a second light-detecting device having a second region operable to receive the reflected second light from the reflective surface and to transmit a third and fourth signals as a function of the location of the received light within the second region; and a processing device coupled with the first and second light-detecting devices to respectively receive the first, second, third, and fourth signals, the processing device operable to transmit a position signal indicative of the distance to the reflected surface as a function of the first, second, third, and fourth signals; wherein the first and second light sources comprise light sources operable to transmit collimated light.