The studies in this dissertation focused on developing dielectric liquid lenses and dielectric liquid irises. Their main body composed of two immiscible dielectric liquids with identical densities. When an external electric field passed through the liquid interface, a dielectric force generated deforms the liquid interface to achieve the function of variable focus for a liquid lens and variable aperture for a liquid iris.
A simple force balance model was proposed to derive a experimental equation, which describes the relationship between actuation contact angle and actuation voltage of the dielectric liquid lens. A dynamic equation was constructed to be the foundation of improving the focusing time. Innovative concentric comb electrodes were proposed to lower the actuation voltage and shorten the actuation time.
The measured results of the dielectric liquid lens in this study achieved a great improvement compared to the published results. The experimental dielectric liquid lens shows that the contact angle changed from 7 ° to 63 ° while the effective voltage range is from 4 to 40Vrms. The maximum diopter change was larger than 154 D, as well as the power consumption downed to 0.3 mW.
The study of the dielectric liquid iris proposed is firstly demonstrated in the world. The iris has a capability to continuously vary its aperture with a truly circular shape. The experimental iris had the initial aperture of aperture 4 mm while its aperture shrunk to 1.5 mm under the maximum actuation voltage of 160Vrms and its transmittance in the range of visible light was above 85%.

本研究專注於開發具低耗電量與低驅動電壓的介電式液態透鏡與介電式液態光圈。其基本主體主要是以兩不互溶之等密度介電溶液組成，當外加電場通過兩液體所形成的介面時，由於兩液體具有介電常數差異，因而在介面上產生介電力，本研究即利用介電力作為兩光學調變元件的驅動機制。介電力會調變液態透鏡內之液體介面的形狀以達到調變屈光度的效果，在液態光圈則會調變液體介面的位置以控制光圈大小。
在介電式液態透鏡的研究主要是在於性能提升以及基本理論機制建立。藉由深入了解介電式液態透鏡的驅動機制，作為性能提升的基礎。本論文提出以作用力平衡模型建構出油珠接觸角與驅動電壓的經驗方程式，並且建立介電式液態透鏡的動態方程式以分析其調變時間。藉由理論分析，本論文提出新式的同心指叉式電極以降低驅動電壓以及縮短調變時間。在介電式液態透鏡性能提升研究的具體成果主要有下列幾點：實驗之介電式液態透鏡的直徑為5.0 mm，在接觸角從7°到63°的變化範圍內，其最大驅動電壓範圍為40 Vrms，屈光度變化可達到154D以及最大耗電量在0.3 mW。
本研究之介電式液態光圈是世界首創之調變液態光圈，其特性為具有連續性調變圓形光圈的能力。實驗量測之介電式光圈的起始孔徑為4 mm，在最大驅動電壓為160Vrms的作用下，其孔徑縮小為1.5 mm，孔徑變化率為62%。由於其驅動機制與介電式液態透鏡相同，故耗電量低，其最大耗電量為5 mW，可見光範圍內之光穿透率在85%以上。

Chapter I Introduction 1
1.1 Motivation 1
1.2 Demands for a optical components used in battery-power device 2
1.3 Dissertation structure 3
1.4 Main contributions 4
Chapter II Introduction of variable focus lenses 5
2.1 Optical theory of auto-focus and zoom in image systems 5
2.2 Introduction of variable focus liquid lenses 9
2.3 Variable focus liquid crystal lens 11
2.4 A liquid-filled lens 13
2.5 A liquid lens by a force directly exerted on liquid interface 15
2.6 Objectives of dielectric liquid lenses 19
Chapter III Theories of dielectric liquid lenses 21
3.1 Two-liquid system 21
3.2 Review of electric field assistant interfacial profile change 26
3.3 Characteristics of coplanar electrode 33
3.3.1 General equivalent circuit of co-planar electrode 34
3.3.2 Electric field simulation in vicinity of contact line 36
3.4 Static analysis of deformation of the liquid interface 41
3.4.1 Pressure balance on the liquid interface 41
3.4.2 Surface tension force due to deformation of the liquid interface 44
3.4.3 Force balance on the liquid contact line 45
3.5 Dynamic analysis of a liquid interface under influence of electric field 46
3.5.1 Dynamic wetting of a droplet on the solid substrate 46
3.5.2 Dynamic contact angle under the influence of the electric field 50
Chapter IV Design and Fabrication of electrode substrates 55
4.1 Design of the actuation electrode substrate 55
4.1.1 Design of coplanar interdigital electrodes 55
4.1.2 Concentric annular electrodes 57
4.1.3 Concentric comb electrodes 61
4.2 Fabrication of a dielectric liquid lens 62
Chapter V Experimetal results and Discussion of dielectric liuqid lenses 67
5.1 Design of a dielectric liquid lens 67
5.1.1 Physical structure of a dielectric liquid lens 67
5.1.2 Liquid consideration 71
5.1.3 Optical design of a dielectric liquid lens 72
5.2 Measurement system 75
5.2.1 Contact angle measurement system 75
5.2.2 Electric measurement system 76
5.2.3 Influence of measured parameters 76
5.3 Static measurement and discussion of a dielectric liquid lens 82
5.3.1 Static measurement of a dielectric liquid lens 83
5.3.2 Influence factor for static characteristics 90
5.5 Dynamic measurement of a dielectric liquid lenses 94
5.5.1 Dynamic contact angle 94
5.5.2 Influence factors for dynamic characteristics 98
5.6 Summary of a dielectric liquid lens 102
Chapter VI Introduction of iris diaphragms 105
6.1 Optical theory of a variable diaphragm 105
6.2 History of a variable iris diaphragm 108
6.3 Non-traditional iris diaphragm 110
6.4 Object of dielectric liquid irises 115
Chapter VII Designa, Measurement and Discussion of dielectric liquid irises 117
7.1 Design of a dielectric liquid iris diaphragm 117
7.1.1 A dielectric liquid iris diaphragm 117
7.1.2 A simple model for estimating the surface tension force 118
7.2 Experimental result and Discussion 122
7.2.1 Measurement result of the dielectric liquid iris 122
7.2.2 Influence of geometrical parameters 125
7.2.3 Thickness influence of the opaque ink 126
7.2.4 Variable hexagon aperture 127
7.3 Summary 128
Chapter VIII Conclusion 129
Reference 131
Appendix A A-1
Appendix B B-1
Appendix C C-1

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