Patents by Inventor Longmin Chen

Longmin Chen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9885556
    Abstract: A dual-frequency grating interferometer displacement measurement system, comprises a dual-frequency laser, an interferometer, a measurement grating and an electronic signal processing component. The measurement system realizes displacement measurement based on grating diffraction, optical Doppler effect and optical beat frequency theory. Dual-frequency laser light is emitted from the dual-frequency laser and split into reference light and measurement light via a polarization spectroscope. The measurement light is incident to the measurement grating to generate positive and negative first-order diffraction. The diffraction light and the reference light form a beat frequency signal containing displacement information about two directions at a photo-detection unit, and linear displacement output is realized after signal processing.
    Type: Grant
    Filed: October 28, 2013
    Date of Patent: February 6, 2018
    Assignee: TSINGHUA UNIVERSITY
    Inventors: Yu Zhu, Ming Zhang, Leijie Wang, Jinchun Hu, Longmin Chen, Kaiming Yang, Dengfeng Xu, Wensheng Yin, Haihua Mu
  • Patent number: 9879979
    Abstract: A displacement measurement system of heterodyne grating interferometer, comprises a reading head, a measurement grating and an electronic signal processing component. Laser light emitted from the laser tube is collimated, passes through the first polarization spectroscope, and then emits two light beams with an orthogonal polarization direction and an orthogonal propagation direction; the two light beams pass through two acousto-optic modulators and respectively generate two first-order diffraction light beams with different frequencies, which are later divided into reference light and measurement light; two parallel reference light beams form a beat frequency electric signal with positive and negative first-order diffraction measurement light respectively after passing through a measurement signal photo-electric conversion unit; the beat frequency signals are transmitted to the electronic signal processing component for signal processing, thus the output of linear displacement in two directions is realized.
    Type: Grant
    Filed: October 28, 2013
    Date of Patent: January 30, 2018
    Assignee: TSINGHUA UNIVERSITY
    Inventors: Ming Zhang, Yu Zhu, Leijie Wang, Jinchun Hu, Longmin Chen, Kaiming Yang, Dengfeng Xu, Wensheng Yin, Haihua Mu
  • Patent number: 9766054
    Abstract: A planar motor rotor displacement measuring device and its measuring method are provided. The motor is a moving-coil type planar motor. The device comprises probes, two sets of sine sensors, two sets of cosine sensors, a signal lead wire and a signal processing circuit. The method is arranging two sets of magnetic flux density sensors within a magnetic field pitch ? along two vertical movement directions in the rotor located in the sine magnetic field area. Sampled signals of the four sets of sensors are respectively processed with a frequency multiplication operation, four subdivision signals are obtained, the zero-crossing points of the four subdivision signals are detected, and then two sets of orthogonal pulse signals are generated. The pulse number of the orthogonal pulse signals is counted, and phase difference of the two sets of orthogonal pulse signals is respectively detected.
    Type: Grant
    Filed: February 8, 2013
    Date of Patent: September 19, 2017
    Assignees: SHANGHAI MICRO ELECTRONICS EQUIPMENT CO., LTD., TSINGHUA UNIVERSITY
    Inventors: Jinchun Hu, Yu Zhu, Wensheng Yin, Longmin Chen, Kaiming Yang, Ming Zhang, Dengfeng Xu, Haihua Mu, Chuxiong Hu, Zhao Liu
  • Publication number: 20150338205
    Abstract: A displacement measurement system of heterodyne grating interferometer, comprises a reading head, a measurement grating and an electronic signal processing component. Laser light emitted from the laser tube is collimated, passes through the first polarization spectroscope, and then emits two light beams with a vertical polarization direction and a vertical propagation direction; the two light beams pass through two acousto-optic modulators and respectively generate two first-order diffraction light beams with different frequencies, which are later divided into reference light and measurement light; two parallel reference light beams form a beat frequency electric signal with positive and negative first-order diffraction measurement light respectively after passing through a measurement signal photo-electric conversion unit; the beat frequency signals are transmitted to the electronic signal processing component for signal processing, thus the output of linear displacement in two directions is realized.
    Type: Application
    Filed: October 28, 2013
    Publication date: November 26, 2015
    Inventors: Ming ZHANG, Yu ZHU, Leijie WANG, Jinchun HU, Longmin CHEN, Kaiming YANG, Dengfeng XU, Wensheng YIN, Haihua MU
  • Publication number: 20150268031
    Abstract: A dual-frequency grating interferometer displacement measurement system, comprises a dual-frequency laser, an interferometer, a measurement grating and an electronic signal processing component. The measurement system realizes displacement measurement based on grating diffraction, optical Doppler effect and optical beat frequency theory. Dual-frequency laser light is emitted from the dual-frequency laser and split into reference light and measurement light via a polarization spectroscope. The measurement light is incident to the measurement grating to generate positive and negative first-order diffraction. The diffraction light and the reference light form a beat frequency signal containing displacement information about two directions at a photo-detection unit, and linear displacement output is realized after signal processing.
    Type: Application
    Filed: October 28, 2013
    Publication date: September 24, 2015
    Inventors: Yu Zhu, Ming Zhang, Leijie Wang, Jinchun Hu, Longmin Chen, Kaiming Yang, Dengfeng Xu, Wensheng Yin, Haihua Mu
  • Publication number: 20150012242
    Abstract: A planar motor rotor displacement measuring device and its measuring method are provided. The motor is a moving-coil type planar motor. The device comprises probes, two sets of sine sensors, two sets of cosine sensors, a signal lead wire and a signal processing circuit. The method is arranging two sets of magnetic flux density sensors within a magnetic field pitch ? along two vertical movement directions in the rotor located in the sine magnetic field area. Sampled signals of the four sets of sensors are respectively processed with a frequency multiplication operation, four subdivision signals are obtained, the zero-crossing points of the four subdivision signals are detected, and then two sets of orthogonal pulse signals are generated. The pulse number of the orthogonal pulse signals is counted, and phase difference of the two sets of orthogonal pulse signals is respectively detected.
    Type: Application
    Filed: February 8, 2013
    Publication date: January 8, 2015
    Inventors: Jinchun Hu, Yu Zhu, Wensheng Yin, Longmin Chen, Kaiming Yang, Ming Zhang, Dengfeng Xu, Haihua Mu, Chuxiong Hu, Zhao Liu