Pixart Imaging Incorporated

Meng-Yee Lim

Gim-Eng Chew

Kuan-Choong Shim

Priscilla Tze-Wei Goh

Chung-Min Thor

There is provided an optical encoding system including a photodiode array and a code disk opposite to each other. The code disk is arranged with multiple code slits at a ring area corresponding to the photodiode array. A length direction of each photodiode of the photodiode array has at least one deviation angle with respect to a length direction of the multiple code slits to reduce the total harmonic distortion in photocurrents.

Optical encoding system with reduced total harmonic distortion

There is provided an optical encoder with alignable relative positions between elements including an encoding medium, a sensor package and a memory. The sensor package includes a photodiode array and two alignment photodiodes opposite to the encoding medium. The memory records an alignment pattern associated with output signals of the two alignment photodiodes when the encoding medium and the sensor package are at nominal operating positions. When the encoding medium and the sensor package are not at the nominal operating positions, the relative position alignment is performed by adjusting current relative positions between the encoding medium and the sensor package to cause a current pattern associated with output signals of the two alignment photodiodes to be identical to the alignment pattern.

Optical encoder with alignment photodiodes at two sides of detection photodiodes

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.

Optical encoding system compensating assembly tolerance

There is provided an optical encoder including an encoding medium, multiple photodiodes and a signal processing circuit. The encoding medium includes an index track. The index track includes a first index pattern and a second index pattern. The multiple photodiodes include a first index photodiode, a second index photodiode and a reference index photodiode for receiving modulated light from the first index pattern and the second index pattern. When the first index photodiode is aligned with the first index pattern and the second index photodiode is aligned with the second index pattern, the signal processing circuit outputs a triggering signal.

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Penang, Malaysia

Meng-Yee Lim