Patent ID: 7894079
Filing Date: 2011-02-22
Classification: G01D

Abstract:
1. A position sensing device comprising: a diffuse light source configured to radiate diffuse source light along an optical axis direction OA, the diffuse light source comprising at least a light generating portion; a position sensitive detector which is fixed relative to the light generating portion and aligned with its sensing surface opposing the diffuse light source and approximately normal to the optical axis direction OA, and with its sensing axis approximately aligned with the measuring axis; and a moving aperture arrangement located between the diffuse light source and the position sensitive detector, and attached to a movable member which is guided linearly over a measuring range that spans a dimension MR along a measuring axis direction which is transverse with the optical axis direction OA, the moving aperture arrangement configured to receive the diffuse source light and output a portion of the diffuse source light to form a measurement spot on the position sensitive detector, the sensed spot moving along the measuring axis direction corresponding to the position of the moving aperture arrangement along the measuring axis direction, wherein the position sensing device is configured such that: