Optical encoding system compensating assembly tolerance
AssigneePixart Imaging Inc.
InventorsKuan-Choong Shim, Meng-Yee Lim, Priscilla Tze-Wei Goh, Gim-Eng Chew
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Abstract
There is provided an optical encoding system including a processor, and a photodiode array and a code disk opposite to each other. The photodiode array includes a detection photodiode group and a calibration photodiode group. If there is a position deviation between the photodiode array and the code disk, the processor determines whether to utilize detection signals of the calibration photodiode group according to phase shifts between detection signals outputted by the detection photodiode group so as to eliminate the phase shifts.
Claims20
An optical encoding system, comprising:
- a code disk, arranged with equally-spaced multiple code slits along a tangential direction;
- a photodiode array, comprising multiple groups of detection photodiodes and two groups of calibration photodiodes respectively at two sides of the multiple groups of detection photodiodes in the tangential direction, wherein the multiple groups of detection photodiodes are respectively configured to receive modulated light from the multiple code slits to generate a detection signal as absolute position signals;
- and
- a processor, configured to identify whether to switch to use the two groups of calibration photodiodes according to phase shifts between multiple detection signals generated by the multiple groups of detection photodiodes,
- wherein each group of the multiple groups of detection photodiodes and the two groups of calibration photodiodes have multiple sub-photodiodes, and the processor is further configured to sum up light energy detected by the multiple sub-photodiodes of the each group to generate the detection signals.
An optical encoding system, comprising:
- a first photodiode array, having a first width in a first direction, and configured to generate multiple detection signals as absolute position signals;
- a second photodiode array, having a second width in the first direction, and arranged at a first side of the first photodiode array in a second direction perpendicular to the first direction, wherein the second width is smaller than the first width;
- a third photodiode array, having a third width in the first direction, and arranged at a second side of the first photodiode array in the second direction, wherein the third width is larger than the first width;
- and
- a processor, configured to identify whether to switch to use the second photodiode array or the third photodiode array according to phase shifts between the multiple detection signals.
An optical encoding system, comprising:
- a code disk, arranged with equally-spaced multiple code slits along a tangential direction;
- multiple detection photodiodes, configured to respectively receive modulated light from the multiple code slits to generate a detection signal as absolute position signals;
- multiple calibration photodiodes;
- and
- a processor, configured to identify whether to switch to use the multiple calibration photodiodes according to phase shifts between multiple detection signals generated by the multiple detection photodiodes.
Dependencies are inferred from the claim text.