微光機電系統與應用技術微光機電系統與應用技術

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台灣師範大學機電科技學系 -1-

微光機電系統與應用技術微光機電系統與應用技術

Optical MEMS Technology and its application Optical MEMS Technology and its application

楊啟榮博士

教授

國立台灣師範大學機電科技學系

Department of Mechatronic Technology National Taiwan Normal University

Tel: 02-77343506 E-mail:ycr@ntnu.edu.tw

C. R. Yang, NTNU MT

Outline Outline

z

Optical MEMS Devices

z

Requirement for optical characteristics

z

Microactuators for optical applications

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Optical MEMS Devices Optical MEMS Devices

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MEMS Applications for 21

^st^st

Century Century

z

Optical MEMS

z

Bio-MEMS

z

RF MEMS

Comparative scale of semiconductor sensors.

μ-mechanical resonator for Frequency band 1MHz~1GHz

Source: NEXUS III, http://nexus-mems.com/

*Other are: microreaction*, chip cooler*, MEMS memories, liquid lenses*, microspectrometer, wafer probes, micro-mirrors for optical processing, micro-pumps*, micromotors, chemical analysis systems*

*

(傾角計)

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傳統的生化分析實驗室傳統的生化分析實驗室

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Artist impression of a hybrid

Artist impression of a hybrid μμTAS dating from the mid 90's. TAS dating from the mid 90's.

全功能微分析系統全功能微分析系統

(micro total analysis system, (micro total analysis system, μμTAS)TAS)

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1. Integration of bio-medical, chemical, optical,

electrical, mechanical, thermal, fluidic system on a chip 2. LOC (Lab On a Chip), or μTAS (Micro Total Analysis

System) 3. Advantages:

a. fast response time b. automation

c. small sample quantity d. low cost

e. high throughput 4. Challenges

a. design and fabrication

b. high complexity of integration and package c. rare sample amount for detection

d. reliability

生醫微機電系統生醫微機電系統

Blood testing Drug delivery

Insulin pump (Debiotech, Switzerland)

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Shrinking Wireless Architectures Shrinking Wireless Architectures

C. T.-C. Nguyen, “Communications applications of microelectromechanical systems (invited),”

Proceed-ings, 1998 Sensors Expo, San Jose, California, May 20, 1998, pp. 447-455.

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Source: http://jbyoon.info/

3D RF One

3D RF One- -Chip Module Chip Module

Integration of all passive components

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MEMS

MEMS - - A New Enabling Technology A New Enabling Technology for Photonic Systems

for Photonic Systems

Optical MEMS Components

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MEMS Micro Optical Bench MEMS Micro Optical Bench

M. C. Wu & H. Toshiyoshi, CNOM 8th Annual Affiliates Meeting

VCSEL (Vertical Cavity Surface Emitting Laser)(面射型雷射 )

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VCSEL stands for Vertical Cavity Surface Emitting Laser, is a semiconductor laser. That is laser-on-a-chip. VCSEL emits light in a cylindrical beam vertically from the surface of a fabricated wafer, and offers significant advantages when compared to the conventional edge-emitting lasers currently used in the majority of fiber optic communications devices.

What is VCSEL?

Conventional edge emitting laser VCSEL

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Micro Optical Bench Micro Optical Bench

R. S. Muller, Berkeley

Functional passive:

Mirror Engine:

Comb actuator

Transmission

Micro optical scanner

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Functional passive:

Mirror

Engine:

Comb actuator

Transmitting mechanism:

Linkage, gear Sandia National Lab.

Micro optical scanner Micro optical scanner

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Answer : No more manual assembling

Built in micro actuators to make 3-D structures

Question : What is the most significant difference between conve Question : What is the most significant difference between conventionalntional machining and micromachining.

machining and micromachining.

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by Built

by Built- -in Actuators in Actuators

H. Toshiyoshi

逐漸消失的

偏振器、極化器

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Filter Polarize

- http://www.youtube.com/watch?v=MNzXrTKEMWg

Polarization (wave polarization) Polarization (wave polarization)

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Refraction Refraction

Fully assembled refractive micolens 300 μm

Ming C. Wu, UCLA http://www.omminc.com/mems.html

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2D Motion by Scratch

2D Motion by Scratch- -Drive Actuators Drive Actuators

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Far Field Beam Profile (1.55 um)

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Luke P. Lee, Berkley, 2002

http://www-biopoems.berkeley.edu/Project-first.php

Confocal

Confocal Microscope Microscope

What is

What is confocal confocal ? ?

In a confocal imaging system a single point of excitation light (from the first pinhole A) is focused onto a confocal spot (S) in the specimen. With only a single point illuminated, the illumination intensity rapidly falls off above and below the plane of focus as the beam converges and diverges, thus reducing excitation of fluorescence for interfering objects situated out of the focal plane being examined. Fluorescent light (i.e. signal) passes back through the dichroic reflector and then passes through the second (exit) pinhole (B), which is confocal with S and A. The exit pinhole can be made small enough that any light emanating from regions away from the vicinity of the illuminated point will be blocked by the aperture, thus providing yet further attenuation of out-of focus interference. A photomultiplier detector (PMT) provides a signal of the light passing scanned S1, S2, S3, S4, etc.(not shown), as the specimen is scanned. A computer is used to control the sequential scanning of the sample and to assemble the image for display.

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A A confocal confocal imaging system imaging system

3D deconvolved blastocyst image

3D PMMA gear image

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Reflection Reflection

Electrostatic Combdrive-Actuated Micromirrors for Laser-Beam Scanning and Positioning

M. H. Kiang, et al., J. MEMS, 7, 27 (1998).

Vertical Scan Horizontal Scan

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H. Toshiyoshi, Hilton Head (2000), J. MEMS 10 (2001)

Electrostatically

Electrostatically Actuated MEMS 2D Optical Scanner Actuated MEMS 2D Optical Scanner

3D Optical Scanner by Single Crystal

3D Optical Scanner by Single Crystal Si Si

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Free Space Integrated Optics Ming C. Wu, UCLA http://www.omminc.com/mems.html

Diffraction Diffraction

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Dynamic focusing microlens

http://www.omminc.com/mems.html M. Wu, et al., 1998

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台灣師範大學機電科技學系 -37- Micrograting

(topside)

(a) Front side (b) back side of the grating

The Grating Light Valve uses reflection and diffraction to create dark and bright image areas.

Grating Light Valve

Grating Light Valve (GLV) (GLV) Reflection and Diffraction

http://www.siliconlight.com/htmlpgs/glvtechframes/glvmainframeset.html Moving ribbon

Fixed ribbon

Air gap Silicon Substrate

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A simple color display can be built using a single light source, single GLV, and rotating RGB filter disk.

An even simpler color display can be built with 3 LEDs (RGB) and a single GLV

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2 Parallel

2 Parallel--plate plate FabryFabry--Perot etalon tuned by translation movementPerot etalon tuned by translation movement http://www.ee.ucla.edu/labs/laser/index.html

Interference

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Lucent, 1998 MARS

MARS – – Mechanical M echanical A Anti nti- -R Reflection eflection S Switch witch

Fully fabricated MARS device Si

Al

Ti/Au SiN_x

Signal

Unbiased mλ/4 air gap (m odd -reflection)

Biased (m-1)λ/4 air gap (m even – anti-reflection)

Optical MEMS Applications Optical MEMS Applications

Micro

Micro- -optical bench optical bench

http://www.ee.ucla.edu/labs/laser/index.html zProjection displays

zFiber switches

zFilters and dispersion compensators

zOptical scanners

zAdaptive Optics

zSilicon Optical Bench

zSensors with optical readout

zInterferometers

zSpectrometers

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Application of Optical MEMS Application of Optical MEMS

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Integrated Free

Integrated Free -Space Optical Disk Pickup Head - Space Optical Disk Pickup Head

http://www.ee.ucla.edu/labs/laser/index.html

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Digital Mirror Display/Digital Light Processing Digital Mirror Display/Digital Light Processing

Texas Instruments 15 μm

光通訊系統傳輸容量的進展光通訊系統傳輸容量的進展

l

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先利用數位或類比調變方式將資訊傳遞到發射機上，以雷射光為載波透過 光纖傳播到遠方。若距離較長，可透過連接器(connector)或接合器(splice) 延長光纖傳送距離，最後以光感測器，把光訊號轉變回電訊號，將原傳送資訊解調回來。

光纖通訊基本架構光纖通訊基本架構

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訊號供應者

訊號接受者

微光學透鏡

旁路開關多工傳輸器

接續器

陣列開關多光纖連接器

分光器多工傳輸解譯器

光通訊系統架構示意圖

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http://www.omminc.com/mems.html

Dynamic focusing microlens Deformable micro mirror

2 X 2 FDDI optical switch

Free Space Integrated Optics Rotating micro mirror

輸入輸出

分波解多工器分波多工器

(a)光訊號作加成/消減(add/drop)示意圖；(b) OXC的架構示意圖

H. Toshiyoshi, Optical MEMS, UCLA, (2002).

Optical cross connector (OXC)

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分波多工分波多工(Wavelength division multiplexing, WDM)

(Wavelength division multiplexing, WDM)

傳統的光纖通訊，是採用單一載波波長傳輸資料。因為技術的演進

，目前的光纖網路可有多個不同波長的頻道同時在一條光纖內傳遞資訊，稱為分波多工系統。

發送器(transmitter) 接收器(receiver)

多工器解多工器

高密度分波多工

高密度分波多工(Dense wavelength division multiplexing, DWDM)

(Dense wavelength division multiplexing, DWDM)

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DWDM基本原理如彩虹，多顏色合併後經光纖傳輸後分開波段 光纖放大器

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Large scale optical cross connector (OXC) Large scale optical cross connector (OXC)

• E. L. Goldstein, J. A. Nagel, J. L .Strand, R. W. Tkach, "Multiwavelength opaque optical-crossconnect network," Lightwave, Feb. 1998.

• M. C. Wu & H. Toshiyoshi, CNOM 8th Annual Affiliates Meeting

Scanning Mirrors for OXC Scanning Mirrors for OXC

OXC: Optical Cross Connector OXC: Optical Cross Connector

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MEMS in WDM Network MEMS in WDM Network

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液晶(Liquid Crystal)一般用於顯示面板，其原理是利用外加 電壓改變液晶的極態，藉由光線的偏極化(polarization)方向

，再加上偏光板達到光的通過與否來做為畫面明與暗的效果

。在光通訊開關方面，下頁圖為其主要應用原理的示意圖，

利用光的偏極化特性，透過外加電壓改變液晶分子的指向來控制光的方向，整個切換過程只須少許電力。液晶技術應用 在光開關產品方面，是適合中型尺寸(80 ports)的光開關，而 由於液晶指向的改變速度不快，有研究發現將液晶加熱可降 低其黏滯力(viscous)，並提高其切換速度(switch speed)。

液晶液晶 (Liquid Crystal)式光開關 (Liquid Crystal) 式光開關

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台灣師範大學機電科技學系 -57- 未施加電壓

液晶分子

施加電壓

液晶分子

液晶式光開關液晶式光開關

Spectraswitch Spectraswitch

液晶式光開關系統原理

液晶光開關圖例

氣泡式的工作原理，主要是利用噴墨方式在交錯排列的波 導(waveguide)交點噴出氣泡，下頁圖為安捷倫(Agilent)的 氣泡式核心技術示意圖，藉此改變光的路徑以達到輸出目 的。目前安捷倫已與Alcatel合作開發此技術，並已有32

× 32

及32

× 16埠數的樣品，其切換速度約為10毫秒(msec)。但是

氣泡式光開關須在密閉環境中操控，也就是必須在密閉環境中保持氣體與液體狀態共存的溫度及壓力，這也是目前氣泡式光開關在技術上所遭遇的困難。

氣泡氣泡 (Bubble)式光開關 (Bubble) 式光開關

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氣泡式光開關氣泡式光開關

Agilent

Horizontal section of the planar lightwave circuit (PLC). Multiple optical paths consist of intersecting waveguides created into the PLC.

A trench is etched at each crosspoint of the waveguides.

Then the trench is filled with a fluid having the same optical properties.

When the optical signal needs to be redirected the fluid is heated up and a bubble is generated.

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As a default condition, the fluid enables the transmission of the light through the waveguide without changing it or deviating it.

When the fluid is heated up the bubble created reflects the light by total internal reflection providing a fast switching function. The optical signal transmitted is deviated but not deteriorated.

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全像術 (Hologram) 式光開關是對電致能布拉格光柵 (electrically

energized Bragg grating)施予電壓，配合一系列不同的折射常數材

料來反射不同的特定波長，當外加一電壓時，布拉格光柵(Bragg

grating)將光線折射到另一方向，未施加電壓時，光則直線通過。全

像術式光開關除了光線切換功能之外，未被切換的光訊號可當作監 視用訊號，具有動態光衰減器(dynamic optic attenuator)的功能。如 下圖所示，上排的出口埠，可做為監視管理之使用。其最大的特色 是光切換速度可達到奈秒級(nsecs)，也適合大規模的交換容量(上千 埠)產品。有鑑以此，全像式光開關技術可能是未來在光路由器

(optical routers)中使用光封包(packet)交換形式唯一可以支援的技術

。

全像術全像術 (Holograms)式光開關 (Holograms) 式光開關

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布拉格光纖光柵

布拉格光纖光柵 (Fiber Bragg Grating , FBG) (Fiber Bragg Grating , FBG)

光源照射

光罩 光纖/波導

布拉格光纖光柵的製作是利用具有週期性結構圖案的光罩置於光纖上，再利用高能 量短波長的紫外線照射後，可在光纖核心(core)部份產生干涉條紋，並永久地改變 其折射率。當一個包含多個波長的光束經過FBG時，大部份波長的訊號只有些微損 耗。但波長恰為光柵週期兩倍的光訊號會被反射回來。例如若反射波的波長是 1550nm，光纖週期就是775nm。FBG的特性與三項因素有關:折射率差距、光柵部 份的長度、製作的精密度。

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熱光熱光 (Thermo- (Thermo -Optical) Optical)式光開關式光開關

Singal input

Thermo-Optic Phase Shifter

1st SW 2nd SW

Output (Off State)

Output (On State)

熱光式光開關有兩種形式：(1) 干涉式(interferometric)熱光式光開關；

(2) 數位式(digital)熱光式光開關。干涉式熱光式光開關主要設計原理是 利用Mach Zehnder干涉型態，入射光線在輸入端被分為兩道，將其中 一道加熱來改變其光行進距離(optical path length)，到了輸出端再加以 組合，如下圖所示。利用兩道光行進距離的不同，造成破壞性及建設性 干涉做為光的方向選擇，主要材料以矽土(Silica)為主。

NTT, Japan NTT, Japan

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聲光聲光 (Acousto ( Acousto- -Optic, AO) Optic, AO)式光開關式光開關

光源

聲波產生器

聲波轉折器

http://www.lmgr.net/aotechnology.htm

聲光式光開關的原理是利用聲波的疏密特性，來暫時改變物體的表面特性

，當光通過聲光偏折器時，會因為聲波造成表面特性的改變，使光線偏折角度不同而到達不同之傳輸目的地。

各種光開關特性之比較

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Requirement for optical characteristics Requirement for optical characteristics

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Reflectivity of Metals

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Coupling Distance of Fibers Coupling Distance of Fibers

Collimated Beam Filter (Ball Lens)

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Source of the Insertion Loss Source of the Insertion Loss

Stability of Mirror Angle Stability of Mirror Angle

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光開關損失之原因

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Fiber Coupling Fiber Coupling

GG--FF Fiber: Fluoride glass Fiber, Multimode, KDDFF Fiber: Fluoride glass Fiber, Multimode, KDD TEC Fiber: Thermally Expanded Core Fiber TEC Fiber: Thermally Expanded Core Fiber

微透鏡陣列製作技術

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Lenses

Gratings Waveguides

Holograms

各種微透鏡種類與應用各種微透鏡種類與應用

(a) 折射式

(b) 繞射式 (c) 混合式

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A: Fresnel 波帶片 B: 平面化二元式Fresnel微透鏡 C: 兩階二元式Fresnel微透鏡 D: 四階二元式Fresnel微透鏡 E: 鋸齒狀Fresnel微透鏡 F: 傳統透鏡

不同之Fresnel不同之

Fresnel透鏡與傳統透鏡之比較圖

透鏡與傳統透鏡之比較圖

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光熱能

Photothermal

水滴式Droplet

折射式或繞射式微透鏡

Refractive or Diffractive Microlens

灰階光罩

Gray Tone Mask

熱回流

Thermal Reflow

準分子雷射微加工

Excimer Laser Micromachining

直寫式

Direct Writing

離子交換

Ion Exchange

微透鏡陣列製造技術微透鏡陣列製造技術

半導體製程

Lithography +RIE etching

Mask

Crystal Substrate

RIE Crystal

Substrate HMDS Coating

Lithography Crystal

Substrate PR

Coating

PR Crystal Substrate

Crystal Substrate Two-Step

Microlens HMDS & PR

Coating

RIE

Lithography

four-Step Microlens

微透鏡之半導體製作流程示意圖微透鏡之半導體製作流程示意圖

Lithography +RIE etching

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Delay Masking Process for

Delay Masking Process for Multistep Multistep Structures Structures

Makoto Mita, et al., HARMST'99, JAPAN.

Rochester Photonics Corp.

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凹面型微光柵元件

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Principle of the VIS

Principle of the VIS- -Spectrometer Spectrometer

Source: http://www.microparts.de/01OPTICVIS.htm Light input λ1….λx

through optical fiber

Light output via

45^oreflecting edge Diode array

Self focusing reflection grating (d=0.2 μm, g=2 μ m)

λ2λ1

Characteristics

zMolded construction allows for cost effective volume pricing

zSmall dimensions, lightweight

zExcellent thermal stability

zLong-term stability

zFlexible operation

zRobust monolithic construction

zNo moving parts

zGrating resolution : 7nm

zSpectral range: 380nm~780nm

zspectral resolution: 7nm (measured at 450 nm)

zDimension：10 × 10 × 5 cm

VIS- VIS -Microspectrometer Microspectrometer PIDC- PIDC -2000 2000

國科會精儀中心

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Grey tone mask technique Shaped light beam method

Direct writing of e-beam

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以離子交換法製作折射率梯度式 (graded-index lenses, GRIN) 微透鏡陣列

Ag⁺溶液

玻璃

GRIN微透鏡陣列

玻璃

離子交換離子交換

(Ion Exchange) (Ion Exchange)

photosensitive glass 紫外光

微透鏡陣列

以光熱能法製作折射式微透鏡陣列示意圖

H. P. Herzig, “Micro-Optics: elements, systems and applications”, Taylor & Francis, 1997.

光熱能光熱能

( (Photothermal Photothermal) )

heating

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台灣師範大學機電科技學系 -85- 接高壓氣體源

Z

Y X

基座微透鏡陣列

玻璃基板 X

Y Z 定位平台

控制器

活塞針筒氣體管路

微噴嘴

微透鏡光學膠

加熱器基板

控制器加熱容器

控制信號

液滴法的儀器架構圖點膠滴置法設備架構圖

水滴式水滴式

(Droplet) (Droplet)

SU- SU -8 8光阻點膠滴置微透鏡陣列製作技術

光阻點膠滴置微透鏡陣列製作技術

微透鏡陣列活塞

針筒

玻璃基板 X

Y Z 定位平台

基座

控制器接高壓

氣體管路氣體源軟烤

UV曝光

曝光後烘烤

點膠滴置微透鏡製作技術

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Preparing

Preparing Photoresist Photoresist Reflow Lens Pattern Reflow Lens Pattern

-88-

Lens Profile Model

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Photoresist

Photoresist Reflow Lens Reflow Lens

Lens Shape (Sag) After

Lens Shape (Sag) After Photoresist Photoresist Reflow Reflow

as a function of initial resist thickness

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Lens Design 1 Lens Design 1

Initial Thickness

Initial Thickness ----> Sag > Sag ----> Radius of Curvature > Radius of Curvature ----> Focal Length> Focal Length

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Lens Design 2 Lens Design 2

Beam Diameter and Lens Diameter

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Lens Design 3 Lens Design 3

Minimum Initial Resist Thickness

Lens Design 4 Lens Design 4

Minimum Resist Thickness and Lens Diameter

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Transferring

Transferring Photoresist Photoresist Pattern into Silicon Pattern into Silicon

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Silicon Micro Lens Silicon Micro Lens

Shape Transferred by RIE

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Effect of

Effect of Photoresist Photoresist Thickness Thickness

Focal Length Simulation

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Beam Spot Diameter Beam Spot Diameter

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Lens Diameter and Beam Spot Diameter

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Excimer

Excimer Laser Laser Micromachining: Mask Dragging Micromachining: Mask Dragging

shaped mask

SU-8光阻微透鏡陣列 光強度分布圖

氦氖雷射 CCD

物鏡

物鏡折射式微透鏡

陣列針孔

透鏡光圈

三維移動平台

光束品質分析器

光學檢測設備架構圖

(Shaped light beam method)

http://www.exitech.co.uk/

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Mask

Workpiece Stage

Fresnel Lens

以以Mask Dragging

Mask Dragging 的方式製作微鏡片

的方式製作微鏡片

(b) Groove pattern of the kinoform cylindrical lens (a) Mask used to make cylinderical lens

Dark: 透光 Clear:不透光

(Shaped light beam method)

-104-

準分子雷射單光罩多層階加工技術準分子雷射單光罩多層階加工技術

光罩圖案

雷射聚焦成像

加工圖案重疊

（光罩移動）

（工件固定）

光罩圖案

1 2 3

2 1

2 3

3 3

3 八階光罩組合

準分子雷射微透鏡加工技術

(53)

準分子雷射微加工準分子雷射微加工

微光學繞射元件製作與檢測

微光學元件檢測系統

像素5 μm四階全像片 “HELLO” 影像輸出

焦平面光強度十六階微透鏡陣列

孔徑250 μm、焦距15 mm

表面檢測光學檢測 準分子雷射LIGA製程

微光機電系統與應用技術 微 光機電系統與應用技術