臺灣博碩士論文加值系統

　光學編碼器為空間定位與距離量測的關鍵元件，常用於半導體、自動化技術、與電子產業上。由於工業要求的精度日益提升，發展高精度的光學編碼器成為現今的重要課題。
光學編碼器包含直線型與旋轉型，而旋轉型光學編碼器又可以分為絕對型光學編碼器與增量型光學編碼器。雖然增量型光學編碼器能夠提供高解析度且易於製作，但僅能提供相對的位置變化資訊；而絕對型光學編碼器則是將絕對的位置座標進行編碼並紀錄於編碼盤中，當光通過編碼盤，接收到的光電訊號經過解碼後，便可以得到絕對位置。由於高解析度的絕對型光學編碼器設計不易突破，所以目前市面上多數設計是結合增量編碼與絕對編碼的複合型光學編碼器。
商用光學編碼器多數以發光二極體(light emitting diode, LED)做為光源，但因為LED為非同調光源，故其光學解析能力有限。由於雷射光源具有高同調性、能量分布集中與波長單一等特性，若以其做為光學編碼器之光源，將有極高的潛力達成高解析度之目的，故本研究將以雷射做為光源，搭配創新的相位差分法探討具高解析度之絕對型光學編碼器設計。
本實驗室先前研究曾設計以紅光雷射為光源，結合繞射光柵之編碼，成功驗證半徑28mm之12位元絕對型光學編碼器。本研究進一步改良先前之設計，並利用相位差分法將解析度提升至14 位元，並加入正弦與餘弦訊號做為額外之增量編碼運用。
研究中以數位訊號模擬、繞射圖像分析以及光電訊號量測三者分別進行，以確認設計之可行性。由結果可得知，新的編碼盤設計之12位元絕對編碼以及2位元相位差皆能被清楚的解析出，實驗與模擬結果差異不大，印證了新的光學編碼器設計確實可以達成14位元的絕對編碼解析度。至於增量編碼的正弦與餘弦訊號，實驗與模擬結果略有差異，推測應與入射光束之聚焦品質有關，值得未來更深入之探討。

The optical encoder is a key device for space positioning and distance measurement. It is often used in the semiconductor, automatic technology, and electronic industries. Owing to the growing requirement of accuracy for industries, developing high accuracy optical encoders currently becomes an important issue.
Optical encoders have liner and rotary forms. The rotary optical encoder can be classified into two types: the incremental optical encoder and absolute optical encoder. Although the incremental optical encoder has the features of high resolution and easy production, it can only provide the relative information of position change. The absolute optical encoder encodes the absolute position coordinates and records them in the coded disk. As light passes through the disk, the absolute position can be obtained by decoding the received optoelectronic signals. Because it is difficult to achieve an absolute optical encoder design with high resolution, most current designs combine ‘incremental’ with ‘absolute’ to be in the form of hybrid optical encoders.
Many commercial optical encoders adopt a LED (light emitting diode) as the light source. However, the LED is an incoherent light source and has limited optical resolving power. With the characteristics of high coherence, concentrated energy distribution, and single wavelength of laser light, it is possible to realize the high resolution optical encoder by using a laser as the light source. Under the circumstances, this study investigates the absolute optical encoder design based on using the laser as the light source in accordance with a creative differential phase method.
Our lab had previously used a red laser diode as the light source and successfully verified 12 bits resolution in a disk coded with diffraction gratings and having the radius of 28 mm. This study further improves the previous design and introduce the differential phase method to provide extra 2 bits resolution. Besides, additional incremental codes by sine and cosine signals are also included in the design.
Digital signal simulation, diffraction pattern analysis, and optoelectronic signal measurement were respectively performed to ensure the design. In the results, 12 bits absolute codes with extra 2 bits from the phase differences were clearly resolved. There was no apparent difference between the experimental and simulated results. It confirms that the novel optical encoder design can practically achieve 14 bits resolution. As for the sine and cosine signals for incremental codes, few differences were observed between the experimental and simulated results. It might be the reason of focusing quality of the incident light beam and still worthy of further discussion.

第1章、 緒論 1
1.1 研究背景 1
1.2 文獻回顧 2
1.2.1 LED光學編碼器 2
1.2.2 雷射光學編碼器 5
1.3 研究動機與目的 8
第2章、 相關理論 9
2.1 光學編碼器原理 9
2.1.1 絕對型光學編碼器 9
2.1.2 增量型光學編碼器 10
2.2 多狹縫繞射光柵 11
2.3 相位差分法 12
第3章、 研究方法與設計模擬 13
3.1 編碼盤設計 13
3.2 繞射光點與光路模擬圖 15
3.2.1 光路模擬 15
3.2.2 繞射光點模擬與設計 16
3.3 光強度訊號模擬 18
3.3.1 模擬方法 18
3.3.2 12 bits光柵繞射強度分布模擬 20
3.3.3 相位差訊號模擬 23
3.3.4 弦波模擬訊號模擬 25
3.4 光罩繪製程式編輯與光罩繪製 26
第4章、 實驗結果 31
4.1 實驗架設 31
4.2 編碼盤成品與繞射光點 32
4.3 繞射圖像訊號分析 36
4.4 光電訊號量測與分析 42
第5章、 結論 49
5.1 未來展望 50

[1]L. Liang, Q. Wan, L. Qi, J. He, Y. Du, and X. Lu, The design of composite optical encoder. The Ninth International Conference on Electronic Measurement & Instruments, 2009. 2: p. 642-645.
[2]T. Kojima, Y. Kikuchi, S. Seki, and H. Wakiwaka, Study on high accuracy optical encoder with 30 bits. The 8th IEEE international workshop on advanced motion control, 2004: p. 493-498.
[3]Y. Matsuzoe, K. Koizumi, T. Saitoh, and T. Yoshizawa, Optimizing design of high-resolution optical encoder using a point-source light-emitting diode with slits. Optical Engineering, 2005. 44(013609): p. 1-7.
[4]J.A. Kim, J.W. Kim, C.S. Kang, J. Jin, and T.B. Eoma, Absolute angle measurement using a phase-encoded binary graduated disk. Mearsurement, 2016. 80: p. 288-293.
[5]J. Seybold, A. Bulau, K. P. Fritz, A. Frank, C. Scherjon, J. Burghartz, and A. Zimmermann, Miniaturized optical encoder with micro structured encoder disc. Applied Sciences-Basel, 2019. 9(3).
[6]Y. Matsuzoe, N. Tsuji, T. Nakayama, K. Fujita, and T. Yoshizawa, High-performance absolute rotary encoder using multitrack and M-code. Optical Engineering, 2003. 42(1): p. 124-131.
[7]蘇裕翔, 全球VCESL產業發展現況. 光連雙月刊, 2001. 35.
[8]C. C. Wu, J. S. Yang, C. Y. Cheng, and Y.Z. Chen, Common-path laser encoder. Sensors and Actuators A: Physical, 2013. 189: p. 86-92.
[9]H.H. Hsieh and W. Chen, Heterodyne Wollaston laser encoder for measurement of in-plane displacement. Optics express, 2016. 24(259629).
[10]J. Guan, P. Köchert, C. Weichert, and R. Tutsch, A high performance one-dimensional homodyne encoder and the proof ofprinciple of a novel two-dimensional homodyne encoder. Precision Engineering, 2013. 37: p. 865-870.
[11]Heidenhain, Rotary encoders, 海德漢公司產品型錄,2018 Available from:https://www.heidenhain.tw/fileadmin/pdb/media/img/349529-2I_Rotary_Encoders_en_01.pdf
[12]H.Yu, X. Jia, Q. Wan, L. Liang, and C. Zhao, High-resolution angular displacement technology basedonVarying moiré figure phase positions. IEEE Sensor Journal, 2019. 19: p. 1558-1748.
[13]W. Gao, S.W. Kim, H. Bosse, H. Haitjema, Y.L. Chen, X.D. Lu, W. Knapp, A. Weckenmann, W.T. Estler, and H. Kunzmann, Measurement technologies for precision positioning. Meaufacturing Technology, 2015. 64: p. 773-796.
[14]V. Mayer, T. Botzelmann, K.-P. Fritz, J. Seybold, and H. Kück, A new concept for an absolutely encoded angular resolver. 4m-net.org, 2007.
[15]V. Mayer, M. Schneider, J. Seybold, T. Botzelmann, K.-P. Fritz, and H. Kück, New high resolution optical incremental rotary encoder. 2nd European conference & exhibition on integration issues of miniaturized systems - MOMS, MOEMS, ICS and electronic components, 2008: p. 1-8.
[16]D. Hopp, D. Wibbing, C. Pruss, W. Osten, J. Binder, W. Schinköthe, F. Sternsd, J. Seybol, K.-P. Fritz, V. Mayer, and H. Kück, A novel diffractive encoding principle for absolute optical encoders. SPIE, 2011. 8082.
[17]邱佳儀, 具有多編碼軌道的繞射式光學編碼器之研究, 國立中興大學機械工程學系碩士論文, 2017
[18]E. Hecht, Optic. 4th ed. 2002: Pearson Education,Inc. p. 696-714.
[19]J. R. Rent Mayer, High-resolution of rotary encoder analog quadrature signals. IEEE Transactions on instrumentation and measurement, 1994. 43: p. 494-498.
[20]P. Yuan, D. Huang, Z. Lei, and C. Xu, An anti-spot, high-precision subdivision algorithm for linear CCD based single-track absolute encoder. Mearsurement, 2019. 137: p. 143-154.
[21] Arduino official website, 2019 ; Available from:: https://www.arduino.cc