1 Yi-Pai HuangAdvanced Display Optics Lab 學研計畫 --- 子計畫二 掃描式光學元件 --- 多電極液晶透鏡 Speaker: Yi-Pai Huang ( 黃乙白教授 ) Department of Photonics and Display Institute, National Chiao-Tung University, Hsinchu, Taiwan Sep. 24, 2009

2 Yi-Pai HuangAdvanced Display Optics Lab 1. 經費使用狀況（ 2009/06/01~2009/08/31 ） 98 年 7 月 累計實際支用數 : $61,504 $61, 月其他人薪水 = $61,504 + $367,429 = $428, 人力聘用情形（ 2009/06/01~2009/08/31 ） 累計實際進用人數 : 14 預定投入人年數 : 108 累計實際投入人年數 : 計畫績效指標 場次人次件數時數 說明會 0000 研討會 0000 審查會 0000 人才培訓 2120 基本資料與進度

3 Yi-Pai HuangAdvanced Display Optics Lab Outline  Introduction - Spatial-Multiplexed 3D - Active Scanning Film  Simulation Results - MeD-LC lens structure design  Experimental Results  Conclusions MeD-LC Lens

4 Yi-Pai HuangAdvanced Display Optics Lab Multiplexed 2D --- Spatial Multiplexed  Parallax Barrier RLRLRLRLRLRL Time LR Display Left-eye image Right-eye image Low Resolution Low Brightness Low Resolution Narrow Viewing Angle

5 Yi-Pai HuangAdvanced Display Optics Lab Active Scanning Film Glass ITO Electrode LC layer Projected light Sub-pixel  Multi-Electrode Driving Liquid Crystal (MeD-LC) Lens Sub-pixel LC layer Glass Electrode Image Applying the operating voltage sequentially : LC layer will reorient and build in a lens-like shape. MeD-LC lens can move(shift) on the horizontal direction  project the images to different viewing angle. Image resolution is without degrading.

6 Yi-Pai HuangAdvanced Display Optics Lab Conventional 2D/3D Switching Method ---Traditional LC Lens Drawbacks: High operation voltageHigh operation voltage Large beam sizeLarge beam size High crosstalkHigh crosstalk

7 Yi-Pai HuangAdvanced Display Optics Lab Theorem and Parabolic n eff Distribution Δn r Ideal Curve LC Layer d f 2r Formulas: where Δn is a parabolic form (Δn: Refractive index difference between the center and the edge of the cell.) 

8 Yi-Pai HuangAdvanced Display Optics Lab MeD-LC Lens: ○ Operation voltage ○ Beam size ○ Crosstalk MeD-LC Lens: ○ Operation voltage ○ Beam size ○ Crosstalk Multi-Electrically Driven LC Lens 2D mode 3D mode

9 Yi-Pai HuangAdvanced Display Optics Lab Simulation and Optimization S i : Simulation curve P i : Ideal parabolic curve Error Function: LC layer d Rubbing direction WSWS WLWL WEWE W L : Lens width W S : Slit width W E : Electrode width MeD-LC Lens: Optimization:  △ n curve of optimized MeD-LC lens  W E :W S v.s EF  # of electrodes v.s EF The most suitable MeD-LC design:  Electrode number = 7  Ratio of Ws:W E = 1:1

10 Yi-Pai HuangAdvanced Display Optics Lab Specification Values Pixel size500umx500um MeDLC width (W L )1508um Electrode width (W E )116um Slit width (W S )116um Cell gap (d)60um ITO thickness0.1um LC material E7 (n e =1.74;n o =1.52) Glass thickness (Top & Bottom) 550um  Structure  Table

11 Yi-Pai HuangAdvanced Display Optics Lab Experiment Setup---Cross Polarizer Me-DLC Lens

12 Yi-Pai HuangAdvanced Display Optics Lab Experimental Results --- Δn Curve Multi-Electrically Driven LC (MeD-LC) Lens is :Multi-Electrically Driven LC (MeD-LC) Lens is : High freedom adjustment --- close to ideal curve High freedom adjustment --- close to ideal curve

13 Yi-Pai HuangAdvanced Display Optics Lab Experiment Setup---Parallel Polarizer Me-DLC Lens Focusing

14 Yi-Pai HuangAdvanced Display Optics Lab V max =30V (Outer electrode) V max =30V (Outer electrode) Beam Size V=62V  Intensity profile CCD image Multi-Electrically Driven LC (MeD-LC) Lens is :Multi-Electrically Driven LC (MeD-LC) Lens is : Smaller Beam size (about 35%) Smaller Beam size (about 35%) Lower operation voltage Lower operation voltage

15 Yi-Pai HuangAdvanced Display Optics Lab Numerical Aperture  NA properties Formulas: n: index of the refraction D: diameter of the lens f : focal length High Crosstalk Low Crosstalk Left eye Right eye f f Left eye Right eye r (mm) Normalized intensity 0 1 r (mm) Normalized intensity 0 1 The NA of the MeD-LC lens is larger than the double  The NA of the MeD-LC lens is larger than the double electrode lens. (about 1.66x) electrode lens. (about 1.66x)  The MeD-LC lens is more applicable than double electrode lens. (low operating voltage) electrode lens. (low operating voltage)

16 Yi-Pai HuangAdvanced Display Optics Lab Issues of Double Electrode LC Lens  Low operating voltage  High operating voltage f  Equivalent lens ． Low Δn  large focal length  Equivalent lens f 2f 2 f 1f 1...  Equivalent lens  Ideal lens Collimated light r (mm) Normalized intensity 0 1 Large Beam size (at FWHM) Bad focusing quality r (mm) Normalized intensity 0 1 Small Beam size (at FWHM) Good focusing quality f 2f 2 f 1f 1... f Left eyeRight eye Left eyeRight eye High Crosstalk Low Crosstalk Formulas: Δn: Refractive index difference d : Cell gap r: lens pitch (FWHM: Full Width at Half Maximum)

17 Yi-Pai HuangAdvanced Display Optics Lab Crosstalk  Crosstalk : 42%  Crosstalk : 24% The crosstalk of Me-DLC lens is lower than double-electrode one. (about 43%)

18 Yi-Pai HuangAdvanced Display Optics Lab Experiment Setup---Scanning Diagram Me-DLC Lens

19 Yi-Pai HuangAdvanced Display Optics Lab Conclusions A novel 3D display with full resolution, freedom of movement and wide viewing angle are presented. Multi-Electrode Driving LC (MeD-LC) Lens Active Scanning Film --- Multi-Electrode Driving LC (MeD-LC) Lens - Small beam size - Low crosstalk - Low voltage - High freedom adjustment ◎ : Small / □ : Large / ○ : good / △ : bad / ☆ : low / ▽ : high MeD-LC lens can move(shift) on the horizontal direction by applying the operating voltage sequentially :  project the images to different viewing angle.  without degrading image resolution.

20 Yi-Pai HuangAdvanced Display Optics Lab Future Work--- Fresnel Lens Formulas: : rotational viscosity : elastic constant : cell gap : threshold voltage : bias voltage: applied voltage

21 Yi-Pai HuangAdvanced Display Optics Lab Turn off the Over-drive Voltage and Switch to the optimized voltage of MeD-LC. Construct two large electrodes and pre-drive an Over-Drive Voltage. Future Work--- Over Drive (24sec → 9sec ) 63% Improvement!!

22 Yi-Pai HuangAdvanced Display Optics Lab 22 Thank you for your kind attention! Display Institute, National Chiao Tung University