Position Encoder with Directional Output
OwnerKeith Wellerinventor
Life of this patent
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Abstract
A method for measuring the position and direction of movement of an object having a simple alternating pattern of light and dark markings using radiant energy where the object is subject to extraneous interfering radiation. The method includes the steps of Illuminating the alternating pattern of light and dark markings with radiation from two or more emitters where the radiation from each emitter is modulated at the same frequency but differing phase, using the modulation component present in the detected signal to separate it from signals caused by interfering radiation, and then using the amplitude and phase information present in this separated signal to determine the position and direction of movement of the object.
Claims6
A method for determining the position and direction of movement of an object having an alternating pattern of light and dark regions, comprising the steps of:
- Illuminating said alternating pattern of light and dark regions on said object with modulated radiation emitted from two or more emitters where said modulated radiation emitted by each of said emitters has substantially the same frequency but distinct phases with respect to each other, and the regions illuminated by each of said emitters are also spatially distinct;
- detecting said illuminating modulated radiation either reflected or transmitted by said alternating pattern of light and dark regions with one or more detectors, wherein each detector produces an electrical signal in response to the radiation impinging upon it;
- using said modulation present in said electrical signals from said one or more detectors to separate the signals produced by said illuminating modulated radiation from the signals produced by extraneous interfering radiation impinging on said detectors;
- and determining the position and direction of movement of the object from said separated signals.
Dependencies are inferred from the claim text.