Journal of the Korean Society of Manufacturing Process Engineers (한국기계가공학회지)

The Korean Society of Manufacturing Process Engineers (한국기계가공학회)
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Optical Path Analysis for the Optical Encoder using Slit Internal Reflection

슬릿 내부 반사를 이용한 광학식 인코더의 광경로 해석

  • Kweon, Yong-Min (School of Mechanical System Engineering, Kumoh National Institute of Technology) ;
  • Kweon, Hyun-Kyu (School of Mechanical System Engineering, Kumoh National Institute of Technology) ;
  • Park, Chang-Yong (School of Mechanical System Engineering, Kumoh National Institute of Technology)
  • 권용민 (국립금오공과대학교 기계시스템공학과) ;
  • 권현규 (국립금오공과대학교 기계시스템공학과) ;
  • 박창용 (국립금오공과대학교 기계시스템공학과)
  • Received : 2017.08.09
  • Accepted : 2017.09.07
  • Published : 2017.10.31
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Abstract

This paper introduces an optical encoder using the reflection in the slit. The digital optical encoder is a sensor to generate a pulse according to the displacement. An optical encoder is composed of 3 parts: light source, slit plate and light-receiving element. In a conventional encoder, one slit produces one signal. The resolution of the digital optical encoder is determined by the number of slits in the encoder plate. The small slit size is most important among the factors that determine the resolution in a generic-type optical encoder. However, a small slit has low productivity and technical difficulties, so analog optical encoders have emerged as an alternative. Nonetheless, this alternative requires additional circuitry and equipment because of the noise and drafts in the analog signals. A new sensor is presented in this paper with a high resolution and a slit of the same size using the reflection in the slit. Then, the path of the light that passes through the slit ccording to the shape was analyzed, and some paths were expressed in the mathematical expressions. In addition, the optical paths were analyzed in the rectangular, octagonal, and circular encoders, and shown the obtained number of signals per slit by using them. Thus, we confirm that this method has the best performance in circle-shaped slits.

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References

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