Optical displacement sensor and torque sensor employing relatively movable slit patterns
First Claim
1. An optical displacement sensor comprising a source of optical radiation, an array of radiation detectors, and first and second elements, each of which comprises alternating first and second regions, the first regions having greater optical transmissivities than the optical transmissivities of the second regions, each of the first and second elements being movable so that the first and second regions pass between the source and the array so as to modulate the radiation falling on different regions of the array, the improvement wherein an image of said first and second regions of the first and second elements is formed on the array which image has light and dark portions with edges and the sensor also includes a data processor connected to the array to receive therefrom signals representing the intensity of radiation falling on each detector of the array, said data processor operating to determine the relative positions of the first and second elements by determining the position of at least one edge of a dark portion of the image caused by one of the second regions of one element relative to at least one edge of a dark portion of the image caused by one of the second regions of the other element.
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Accused Products
Abstract
An optical displacement sensor is used to measure the rotary displacement between two shafts which rotate together. By connecting the shafts together by means of a torsion bar, the sensor may be used to measure transmitted torque. The sensor comprises first and second coaxial discs mounted on the shafts and having slots formed therein. A light source directs light through the slots onto an array of photodetectors and a data processor determines the displacement or torque from the positions on the array of images of the slot edges.
44 Citations
29 Claims
- 1. An optical displacement sensor comprising a source of optical radiation, an array of radiation detectors, and first and second elements, each of which comprises alternating first and second regions, the first regions having greater optical transmissivities than the optical transmissivities of the second regions, each of the first and second elements being movable so that the first and second regions pass between the source and the array so as to modulate the radiation falling on different regions of the array, the improvement wherein an image of said first and second regions of the first and second elements is formed on the array which image has light and dark portions with edges and the sensor also includes a data processor connected to the array to receive therefrom signals representing the intensity of radiation falling on each detector of the array, said data processor operating to determine the relative positions of the first and second elements by determining the position of at least one edge of a dark portion of the image caused by one of the second regions of one element relative to at least one edge of a dark portion of the image caused by one of the second regions of the other element.
- 23. An optical displacement sensor comprising a source of optical radiation, an array of radiation detectors, first and second elements, each of which comprises alternating first and second regions, the first regions having greater optical transmissivities than the optical transmissivities of the second regions, each of the first and second elements being movable so that the first and second regions pass between the source and the array, and a detector for detecting locations on the array of transitions between a radiation level greater than a predetermined level and a radiation level less than the predetermined level.
- 27. An optical displacement sensor comprising a source of optical radiation, an array of radiation detectors, and first and second elements, each of which comprises alternating first and second regions, the first regions having greater optical transmissivities than the optical transmissivities of the second regions, said first element comprising n second regions, (n-1) of which have a first width and the other of which has a second width different from the first width, each of the first and second elements being movable so that the first and second regions pass between the source and the array.
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29. An optical displacement sensor comprising a source of optical radiation, an array of radiation detectors, first and second rotary elements, each of which comprises alternating first and second regions, the first regions having greater optical transmissivities than the optical transmissivities of the second regions, each of the first and second elements being movable so that the first and second regions pass between the source and the array, and a data processor connected to the array for transforming positions of images of the first and second regions to corresponding rotary positions of the first and second regions.
Specification