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公开(公告)号：US11774269B2
公开(公告)日：2023-10-03
申请号：US17710096
申请日：2022-03-31
Applicant: PixArt Imaging Inc.
Inventor： Kuan-Choong Shim , Gim-Eng Chew
CPC classification number: G01D5/34715 , G01D5/24428 , G01D5/24457 , G01D5/24466 , G01D5/24471 , G01D5/24476 , G01D5/3473
Abstract: There is provided a light control circuit including a light detector, a frequency detector, an error amplifier, an NMOS driver and a light source. The frequency detector identifies a signal frequency according to detected voltage signals outputted by the light detector and generates a control signal accordingly. The NMOS driver changes a drive current of the light source according to an output of the error amplifier. The error amplifier changes a bandwidth thereof according to the control signal from the frequency detector to regulate a response time of the drive current of the light source.
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公开(公告)号：US11740108B2
公开(公告)日：2023-08-29
申请号：US17104822
申请日：2020-11-25
Applicant: PixArt Imaging Inc.
Inventor： Kuan-Choong Shim , Gim-Eng Chew , Priscilla Tze-Wei Goh , Meng-Yee Lim
CPC classification number: G01D5/3473
Abstract: 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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公开(公告)号：US11371864B2
公开(公告)日：2022-06-28
申请号：US17355177
申请日：2021-06-23
Applicant: PIXART IMAGING INC.
Inventor： Swee-Lin Thor , Gim-Eng Chew
Abstract: There is provided an interpolation circuit of an optical encoder including a phase shifter circuit, two multiplexers, two digital circuits and four comparators. The phase shifter circuit receives signals sequentially have a 90 degrees phase shift and outputs multiple phase shifted signals. Each of the two multiplexers receives a half of the multiple phase shifted signals and outputs two pairs of phase shifted signals, each pair having 180 degrees phase difference, respectively to two comparators connected thereto. Each of the two digital circuits controls the corresponding multiplexer to select the two pairs of phase shifted signals from the half of the multiple phase shifted signals.
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Patent Agency Ranking
公开(公告)号：US20240361158A1
公开(公告)日：2024-10-31
申请号：US18677941
申请日：2024-05-30
Applicant: PixArt Imaging Inc.
Inventor： Kuan-Choong Shim , Meng-Yee Lim , Priscilla Tze-Wei Goh , Gim-Eng Chew
CPC classification number: G01D5/34723 , G01D5/3473 , G01D18/001 , G01D2205/20
Abstract: There is provided an optical encoding system including 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, whether to utilize detection signals of the calibration photodiode group is determined according to phase shifts between detection signals outputted by the detection photodiode group so as to eliminate the phase shifts.
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公开(公告)号：US11709077B2
公开(公告)日：2023-07-25
申请号：US17545116
申请日：2021-12-08
Applicant: PixArt Imaging Inc.
Inventor： Kuan-Choong Shim , Gim-Eng Chew
IPC: G01D5/347
CPC classification number: G01D5/3473 , G01D5/34707
Abstract: There is provided an optical encoder including a photodiode array and a code disk opposite to each other. The photodiode array includes at least three sets of position photodiodes and two index photodiodes arranged transversally. The two index photodiodes are adjacently arranged at the same side of the at least three sets of position photodiodes. A first set of position photodiodes and a last set of position photodiodes of the at least three sets of position photodiodes are partially covered to alleviate the total harmonic distortion. The rest position photodiodes of the at least three sets of position photodiodes other than the first and last sets of position photodiodes are not covered.
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公开(公告)号：US11616503B2
公开(公告)日：2023-03-28
申请号：US17742999
申请日：2022-05-12
Applicant: PixArt Imaging Inc.
Inventor： Swee-Lin Thor , Gim-Eng Chew
Abstract: There is provided an optical encoder including a phase shifter circuit, two multiplexers, two digital circuits and four comparators. The phase shifter circuit receives signals from an amplifier and outputs multiple phase shifted signals. Each of the two multiplexers receives a half of the multiple phase shifted signals and outputs two pairs of phase shifted signals, each pair having 180 degrees phase difference, respectively to two comparators connected thereto. Each of the two digital circuits controls the corresponding multiplexer to select the two pairs of phase shifted signals from the half of the multiple phase shifted signals.
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公开(公告)号：US11237024B2
公开(公告)日：2022-02-01
申请号：US16583972
申请日：2019-09-26
Applicant: PixArt Imaging Inc.
Inventor： Kuan-Choong Shim , Gim-Eng Chew
IPC: G01D5/347
Abstract: There is provided an optical encoder including a photodiode array and a code disk opposite to each other. The photodiode array includes at least three sets of position photodiodes and two index photodiodes arranged transversally. The two index photodiodes are adjacently arranged at the same side of the at least three sets of position photodiodes. A first set of position photodiodes and a last set of position photodiodes of the at least three sets of position photodiodes are partially covered to alleviate the total harmonic distortion. The rest position photodiodes of the at least three sets of position photodiodes other than the first and last sets of position photodiodes are not covered.
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公开(公告)号：US11108385B1
公开(公告)日：2021-08-31
申请号：US16907948
申请日：2020-06-22
Applicant: PixArt Imaging Inc.
Inventor： Chung-Min Thor , Kuan-Choong Shim , Gim-Eng Chew
Abstract: There is provided a phase shifter circuit of an optical encoder that receives four signals generated from photodiodes. The phase shifter circuit includes four resistor strings each coupled to two of the four signals having a 90-degrees phase pitch. By taping out different numbers of signals at different tape-out nodes of each of the four resistor strings, the phase shifter circuit is adapted to output signals for different interpolation factors without changing the mask set.
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