28 December 2010 Reflective-type optical encoder based on fractional Talbot self-image effect using phase grating
Author Affiliations +
Proceedings Volume 7544, Sixth International Symposium on Precision Engineering Measurements and Instrumentation; 75440N (2010); doi: 10.1117/12.886238
Event: Sixth International Symposium on Precision Engineering Measurements and Instrumentation, 2010, Hangzhou, China
Abstract
This study presents a reflective-type optical encoder based on fractional Talbot self-image effect using a phase grating. An amplitude grating image is produced by the phase grating at a quarter or three quarters of Talbot distance. The encoder has the advantages of a large gap and more light efficiency. This work use a 850nm Light-Emitting Diode (LED) as light source, the light source will be collimated by a collimator ,and incident on a phase grating by 45° angle. The fractional Talbot self-image of phase grating is produced and projected on an amplitude index grating. The Moiré interference is occurred when the both gratings displaced from each other. The encoder includes a reflective-type phase-grating scale with period 20 μm and an index-amplitude grating. The gap between the phase index grating and mail scale was increased to three quarters of Talbot distance. The tolerance of gap between the index and main grating is 0.1 mm. The tolerance of yaw motion is ± 0.25°.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ching-Fen Kao, Sheng-Hua Lu, "Reflective-type optical encoder based on fractional Talbot self-image effect using phase grating", Proc. SPIE 7544, Sixth International Symposium on Precision Engineering Measurements and Instrumentation, 75440N (28 December 2010); doi: 10.1117/12.886238; https://doi.org/10.1117/12.886238
PROCEEDINGS
6 PAGES


SHARE
KEYWORDS
Computer programming

Reflectivity

Optical encoders

Tolerancing

Light emitting diodes

Light sources

Collimation

RELATED CONTENT

Full-field wafer warpage measurement technique
Proceedings of SPIE (June 26 2017)
Miniaturised optical encoder
Proceedings of SPIE (September 02 2008)
High-resolution encoder using double gratings
Proceedings of SPIE (July 27 1995)

Back to Top