Fabrication of Anti-reflection Film with Sub- wavelength Structures Using Roll-to-Roll imprinting Reporter ﹕ Po-Hsiang Wang ( 王柏翔 ) Advisor ： Deng-Maw LU ( 盧燈茂 ) Cheng-Hsin Chuang ( 莊承鑫 ) Cheng-Hsin Chuang ( 莊承鑫 ) Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan Date: 2015/05/13 運用滾對滾轉印技術製作具次波長結構之抗反射膜

Outline 2 Introduction Experimental setup and results Anti-reflection film measurement Conclusions  Porous Anodic Alumina Oxide (AAO) Template  R2R Nanoimprinting process  The transmittance and reflectance measurement results  Motivation  Types of Anti-reflection film

Outline 3 Introduction Experimental setup and results Anti-reflection film measurement Conclusions  Porous Anodic Alumina Oxide (AAO) Template  R2R Nanoimprinting process  The transmittance and reflectance measurement results  Motivation  Types of Anti-reflection film

4 Motivation Reflection Low contrast Decreased conversion efficiency Low transmittance Disadvantages of light reflection n=1.5 Air n=1 n=1.5 n=1.1~1.4 10%

5 Antireflective coating technology – Multilayer coating Antireflective structure – Sub-wavelength structure (SWSs) Protective film Antireflection layer Substrate with hard coating Adhesive layer Separator The refractive index of multilayer (Ladder) High-cost facilities Types of Anti-reflection film

6 Antireflective structure - Sub-wavelength structure (SWSs)  Moth eye structures The reflective index of cylindrical SWSs The reflective index of cone-shape SWSs Information source : FINETECH JAPAN 2011 Multilayer coating The lowest reflection and broadband Sub-wavelength Structures(SWSs) The best optical characteristic NanoImprinting process Low-cost How to achieve broadband and omnidirectional antireflection with low cost process?

7 Types of Sub-wavelength structures (SWSs) SWSs AAO Template TraditionalHomemade Disadvantages Complex High-end facilities Costly Small size Advantages Low-cost nano- scale mold Simple process The best optical characteristic Large area book edited by Xihong Peng, ISBN , Published: December 19, 2012 under CC BY 3.0 licenseCC BY 3.0 license

Outline 8 Introduction Experimental setup and results Anti-reflection film measurement Conclusions  Porous Anodic Alumina Oxide (AAO) Template  R2R Nanoimprinting process  The transmittance and reflectance measurement results  Motivation  Types of Anti-reflection film

9 Idea of Fabricating the Sub-wavelength Structures(SWSs) Anodization Aluminum Oxide (AAO) Technique R2R UV curing process Anti-reflection (AR) film Mold fabrication Fabrication Pattern transformation Optical measurement 9 Nano imprinting lithography

10 Experimental setup – Large area anodization process Facilities for anodization Advantages Maintain at the low temperature state Large area AAO template can be done O I 40V 1A DC Power supply

11 Experimental – Fabrication of AAO template Procedures Pure aluminum substrate 1 st anodization process Removed anodic oxide layer by acid 2 nd anodization process 1 st anodization process Applied voltage (V) Electrolyte (Oxalic acid) Time (min) Temperature ( ℃ ) 400.3M304 2 nd anodization process Applied voltage (V) Electrolyte (Oxalic acid) Temperature ( ℃ ) Widening time (min) 400.3M3210 Anodizing + etchig = 1 time (1 st cycle) Anodizing + etchig = 1 time (2 nd cycle)

12 Experimental result – Different 2 nd anodization time Top view Widening time 10min, repetition times N=5 Cross section view 297 mm Ø90 mm

Experimental result – Different 2 nd widening time 10min 10 、 8 、 6 、 4 、 2min

Outline 14 Introduction Experimental setup and results Anti-reflection film measurement Conclusions  Porous Anodic Alumina Oxide (AAO) Template  R2R Nanoimprinting process  The transmittance and reflectance measurement results  Motivation  Types of Anti-reflection film

Experimental process – R2R Nanoimprinting process Roll to roll for replicating sub-wavelength on PET UV light AAO template Strain Control System Scraper Coating system PET film UV resin Pre-heat system SWSs

Outline 16 Introduction Experimental setup and results Anti-reflection film measurement Conclusions  Porous Anodic Alumina Oxide (AAO) Template  R2R Nanoimprinting process  The transmittance and reflectance measurement results  Motivation  Types of Anti-reflection film

17 Optical measurements results – Transmittance (%) Transmittance and of the PET plate with/without SWSs SWSs (aspect ratio 1:2.2) 89%92% SWSs (aspect ratio 1:1) SWSs (aspect ratio 1:0.5)

18 Optical measurements results – Reflectance (%) Reflectance and of the PET with/without the SWSs 1% 5% 4.2% 4.6% Incident light angles 4.2% 6.4%

Outline 19 Introduction Experimental setup and results Anti-reflection film measurementConclusions  Porous Anodic Alumina Oxide (AAO) Template  R2R Nanoimprinting process  The transmittance and reflectance measurement results  Motivation  Types of Anti-reflection film

20 Conclusions 本實驗成功利用不同的陽極處理時間及擴孔時間循環得到不 同深款比的尖錐狀孔洞之陽極氧化鋁模板。 成功控制不同擴孔時間製作具多孔性尖錐狀陽極氧化鋁模板。 成功利用低成本的奈米滾印技術製作大面積具次波長之抗反 射光學膜。 此抗反射光學膜穿透率有效提升 3%; 反射率從 5% 下降至 1% 。 未來將完成高純度鋁靶材滾筒製作具次波長結構之抗反射光 學膜及使用 H-PDMS 製做抗反射玻璃。

21 Thanks for your attention !! STUST