The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 03, 2012
Filed:
Jun. 12, 2009
Kuei-chu Hsu, Tainan County, TW;
Chii-chang Chen, Taoyuan County, TW;
Chia-hua Chan, Taoyuan County, TW;
Yin-chieh Lai, Taichung, TW;
Kuei-Chu Hsu, Tainan County, TW;
Chii-Chang Chen, Taoyuan County, TW;
Chia-Hua Chan, Taoyuan County, TW;
Yin-Chieh Lai, Taichung, TW;
National Chiao Tung University, Hsinchu, TW;
Abstract
A displacement measurement system including a coherent light source, a two-dimensional grating, a photo sensor, and a signal processing apparatus is provided. After the coherent light beam enters the two-dimensional grating, a zero-order light beam and a plurality of first-order diffraction beams are generated. The zero-order light beam interferes with two of the first-order beams in different directions, so that corresponding interference fringes are formed on the photo sensor. Accordingly, when the two-dimensional grating moves, displacements of the two-dimensional grating in the different directions are obtained by calculating phase differences of the interference fringes in the corresponding directions. Besides, when the two-dimensional grating rotates, the rotational angle of the two-dimensional grating is obtained from the corresponding rotational angle of a diffraction pattern of the first-order diffraction beams.