15,018 research outputs found
Reliability of a MEMS Actuator Improved by Spring Corner Designs and Reshaped Driving Waveforms
No full textmechanization of lily microbulb
No full textmechanization of lily microbulb multiplication operations. ta-te lin & ching-lu hsieh. department of agricultural machinery engineering.. national taiwan university.. taipei. taiwan. roc. mechanization of lily microbul
An electro-magnetic micromachined actuator monolithically integrated with a vertical shutter for variable optical attenuation
No full textRecommended from our members
Too rich city: a Sinofuturist playground
No full textThe artwork Too Rich City transforms China’s housing crisis into a virtual playground, where NFT properties and augmented reality offer young people alternative forms of urban belonging. Hsin Hsieh both embraces and critiques this artwork
Data supporting the results in the paper: Sheng-Hsin Su, Biing T. Guan, Chia-Hao Chang-Yang, I-Fang Sun, Hsiang-Hua Wang, Chang-Fu Hsieh. In press. "Multi-stemming and size enhance survival of dominant tree species in a frequently typhoon-disturbed forest". Journal of Vegetation Science.
No full textData supporting the results in the paper:Sheng-Hsin Su, Biing T. Guan, Chia-Hao Chang-Yang, I-Fang Sun, Hsiang-Hua Wang, Chang-Fu Hsieh. In press. "Multi-stemming and size enhance survival of dominant tree species in a frequently typhoon-disturbed forest". Journal of Vegetation Science. https://doi.org/10.1111/jvs.12858</div
The Analysis and Improvement of Low Actuation Voltage MEMS for 2D Optical Switches in Optical Communications
No full text隨著頻寬需求的成長，光通訊變的日趨重要，全光學式(O-O-O)的微機電(MEMS)式光切換器因有相對優良的特性，可以廣泛的運用在光通訊上分波多工(WDM)系統的波長加減(add/drop)模組中。
本文中介紹一個小巧且由電磁力致動的低電壓微機電式光切換器，它的核心是一個垂直光行進路徑移動的微小鏡子，為了避免沾黏(stiction)的問題，透過彈簧來連接擺動的部分，但是這麼做會產生擺動幅度過大的不良影響，根據分析和模擬的結果，我們使用了一些技巧來克服這個困難，首先，我們模擬磁場的分布狀況，並且找到一個適當的位置來放置晶片，接著我們將本來使用的collimator換成lensed fiber，藉此來縮小光聚焦的範圍，最後我們根據傅立業(Fourier)轉換函數，發展出一套快速找尋特殊波形的方法，這個方法可以提升切換的速度，並且可以容忍因為製程所引起的些微誤差。
最後的實驗結果顯示，致動電壓僅需0.5V，切換時間大約是3ms，因為鏡面所引起的插入損耗(insertion loss)大約為0.45dB，WDL為0.05dB，TDL少於0.05dB，PDL 少於0.1dB. 整個元件的體積很小，適合和其他元件整合在同一個光通訊系統中。Optical communications become more and more important due to the growth of bandwidth requirement. Transparent (O-O-O) MEMS optical switches are applied in add/drop switch modules in WDM systems with relative good performance.
A compact MEMS optical switch with low actuation voltage is demonstrated in this thesis. It is actuated by electromagnetic force. The kernel is a moving micromirror which is perpendicular to the light propagation. The flap is connected by serpentine springs to prevent the stiction problem. The trade-off for stiction-free (or no stopper) is large vibrations. To overcome this difficulty, several techniques are discussed in this thesis. We start from the simulation of magnetic field intensity and find the best position for the magnetic flap. Secondly, we analyze the optical property. To reduce the vibration, the collimator is replaced by a lens fiber with small beam size. Finally, we develop a fast method for finding a special driving waveform to achieve fast switching time based on Fourier transform function. This method also can tolerate the variation in fabrication processes.
Our experimental results show the actuated voltage is 0.5 volts. The switching time is about 3ms. The insertion loss caused by the micromirrors is 0.45 dB, WDL is 0.05 dB. TDL is less then 0.05 dB. PDL is less than 0.1 dB. The size is compact for the integration in optical communications.致謝 I
中文摘要 II
Abstract III
Contents IV
Lists of Figures VI
Lists of Tables VIII
Chapter 1 Introduction 1
Chapter 2 Applications of MEMS in optical communications
2-1 MEMS 5
2-2 Optical communications 10
2-3 MEMS optical switches in fiber communications 14
2-4 Standards for MEMS optical switches 16
Chapter 3 Fabrication, Design, and Theory
3-1 Switches fabrication and package designs 21
3-2 Problems in switches operation 26
3-3 Theory for performance improvement 30
3-3.1 magnetic simulation and optimized 30
3-3.2 mechanical model and Fourier analysis 33
3-3.3 method for optical improvement 39
Chapter 4 Experimental results and discussions
4-1 Magnet optimization 45
4-2 Optical improvement 52
4-3 Driving by a special waveform 59
4-4 Performance and discussions 69
Chapter 5 Conclusion 75
Appendix A Matlab® code for special waveform editing 78
Appendix B The Jones matrix method for PDL measurement 84
References 8
Design and Fabrication of Compact Optical Devices:Organic Deformable Mirror and Microlens Arrays
No full text在本篇論文中，我們利用微製程技術發展並製作一個有機可形變面鏡 (organic deformable mirror) 和一個微透鏡陣列 (microlens array)，並展現整合此二元件和一般光學元件後，用來發展微小光學系統的潛力。
發展有機可形變面鏡的過程中，我們利用聚亞醯銨 (polyimide) 來製作一具高度可撓性的薄膜，使薄膜具有低的楊氏系數 (Young’s modulus, 小於10 GPa ) 和低的殘餘應力 (residual stress, 藉由挑選和基板之熱膨脹係數符合的薄膜材質可小於5 MPa)，薄膜表面鍍有鋁用以反射或聚焦入射的光線，藉由施加在薄膜(鋁)和下電極間的電壓，可使此有機可形變面鏡因為靜電力吸引而下凹產生曲率，並藉此電壓來控制其度數 (diopter, m-1)，製作出來的有機可形變面鏡有低驅動電壓和大位移量的特性 (約只需150伏特的電壓,即可達到20-diopters)，這使得此有機可形變面鏡有些特殊的應用，例如，在本篇論文中，我們用它製作一兩百萬畫素的薄型自動對焦鏡頭模組；另外，我們也推導出一個解析的模型來預測，當使用不同材料來做有機可形變面鏡時，特定鏡面度數下所需施加電壓的大小。除此之外，我們利用馬達驅動的位移平台、顯微鏡和自動對焦的演算法 (Tenengrad) ，發展了一套自動系統,用以量測製作出來的有機可形變面鏡之楊氏系數和殘餘應力。
在微透鏡陣列的發展過程中，我們提出了兩個製程技術用以提升微透鏡陣列的特性。其一是“邊界局限法”,此方法可以製作出同時具有高填充率和小半徑曲率特性的微透鏡陣列。實驗結果顯示，每個微透鏡的高度是22 μm直徑是48 μm而間距只有2 μm，我們也可以藉由這個方式來製作具有隨機曲率分布的微透鏡陣列；另一技術是透過PDMS覆蓋層來增加微透陣列的焦距，一般來說，由熱回熔(thermal reflow) 技術做出的微透鏡陣列,因受限於熔化光阻和基板間的接觸角，焦距長度有一定的限制，此技術可使直徑240 μm的微透鏡之焦長延長至2.1 mm (約原本的三倍)，這兩個方法使我們在設計微透鏡時有更多的彈性。
最後，我們希望這篇文章可以啟發相關的研究人員，並對後續的發展有些許貢獻。We demonstrated the potential of wafer level optical components for compact optical systems by developing two micro optical components: organic deformable mirror (DM) and microlens arrays (MLA) which was fabricated by MEMS technology.
In the development of organic deformable mirror, we fabricated a highly flexible polyimide membrane which has low Young’s modulus (<10 GPa) and low residual stress (<5 MPa, by choosing the CTE of membrane material, which matches to a silicon substrate). The incident light is reflected or focused by the Aluminum coating layer on the membrane. The optical power (diopter, m-1) of DM is curved and controlled by the gap-closing force results from the applied voltage between membrane (Aluminum coating) and bottom electrode pad. This polymer DM has advantages on large stroke and low applied voltage (~150 V achieved 20-diopters, lower voltage is possible). The fabricated DM could be integrated with other optical components for imaging applications. We show a thin 2M-pixels camera module with autofocus (AF) facility provided by DM rather than voice coil motor (VCM). The object position of clear image varies from 4 cm to infinity. In addition, we derived an analytic model, which predicts the optical power with required applied voltage according the material properties of membrane. Besides, an automatic system for measurement on Young’s modulus and residual stress was developed and implemented by a motorized stage, optical microscope, and image processing algorithm (Tenengrad).
In microlens process, we developed two fabrication techniques. One is “boundary-confined method” which achieves high fill factor and small radius of curvature or high numerical aperture (NA) simultaneously. The height of microlens is 22 μm and the diameter is 48 μm, and the gap is 2 μm. In addition, the various curvature distribution (VCD) over microlenses in a MLA could be made based on this method. The other technique in microlens process extends the focal length of microlens by a covering Polydimethylsiloxane (PDMS) layer. The focal length of microlens with 240 μm diameter is extended to around 2.1 mm or 3 times larger than origin. It is longer than the maximum focal length of microlens, which is limited by the contact angle of photoresist and substrate in thermal reflow process. Therefore, designer could have more flexibility on the MLA design for specific applications. Finally, we believe this integration on MEMS technology and optical systems could inspire the researchers to develop compact and convenient optical systems which might benefit to the human
A taxonomic revision of Stanjehughesia (Chaetosphaeriaceae, Sordariomycetes), with a novel species S. kaohsiungensis from Taiwan
No full textHsieh, Sung-Yuan, Goh, Teik-Khiang, Kuo, Chang-Hsin (2021): A taxonomic revision of Stanjehughesia (Chaetosphaeriaceae, Sordariomycetes), with a novel species S. kaohsiungensis from Taiwan. Phytotaxa 484 (3): 261-280, DOI: 10.11646/phytotaxa.484.3.2, URL: http://dx.doi.org/10.11646/phytotaxa.484.3.
Hsin-Ming Hsu Cello Recital Program Notes
No full textThe concert is selected from two pieces of music of different schools and countries, spanning from the works of the late 18th century to the 20th century. The works include Ludwig van Beethoven\ue2s Cello Sonata in G Minor, Op. 5 No. 2 and Gaspar Cassad\uc3\ub3\ue2s Suite for Violoncello Solo. The program notes will explore the life of the composer, the analysis of the structure of his works and his creative techniques
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