| 摘要 |
A position detector system (12) for determining the angular position of a rotatable element (14), the detector system (12) having a single light source (46) for directing a uniform wide angle field of light in a direction along the longitudinal axis of the rotatable element (14), multiple sector-shaped detectors aligned circumferentially about to receive light from the light source (46), a light blocker (30) connected to the rotatable element (14) to rotate therewith about the longitudinal axis for periodically blocking portions of the light which impinge upon the light detectors. The space (B) between the light source and the detectors being essentially free of any object, except for the light blocker (30), so that the light from the light source (46) can impinge directly upon at least those portions of the detectors which the light blocker (30) is not blocking, without passing through any other object. A linear output from the detectors is for measuring the angular position of the rotatable element (14).
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