| 摘要 |
Positional sensors receive light that has been reflected off a pair of complementary geometric patterns carried by a supporting carrier surface that is displaceable with respect to the sensors. The sensors view the patterns through viewing windows as the carrier surface and sensors are displaced laterally with respect to each other, presenting differing portions of the patterns to the sensors. The patterns are shaped to produce outputs which, when their difference value is extracted, provide output signals that are a measure of the displacement of the carrier surface with respect to the sensors and in which common mode errors are minimized. |
