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Integrated microlens array on a transparent film, called an optical film, provides interesting applications for various fields. In a FPD (Flat Panel Display), the optical films are the more important components to improve the efficiency and quality. In this dissertation, a diffuser film which consisted of two different microlens arrays on the two surfaces of a film was developed and used to enhance the brightness and uniformity of a light source. There were also several microlens arrays developed, such as a hexagonal microlens array with gap and gapless, a gapless dual-curvature microlens array and a diffuser film. A process called polygonal microlens array process had been used to manufacture them. It had advantages of mass production, various polygonal shapes and 100% fill-factor. A softer mold of PDMS and a metal mold of NiCo alloy were utilized to replicate the MLAs. In this dissertation, several replication processes were applied to mass product and to find out which one is more suitable for the diffuser film. In this dissertation, the results of different shapes and dimensions of microlens arrays showed various light distribution. Therefore, for searching a more suitable and novel layout of a diffuser, Taguchi Method with simulation was used to design the layout of a diffuser film before fabrication process. Finally, a diffuser film was measured and demonstrated its optical effects. According to the results of measurement and simulation, the average intensity and the S/N ratios were shown. The trend of simulation and measurement was also similar.

This aim of this dissertation is to fabrication microlens arrays (MLA) by silicon mold using dry etching technique and imprint on the PET substrate by direct imprinting microlens structures on Polyethylene terephthalate (PET) substrates using Si molds.The MLA on PET substrates can be used to increase light emitting efficiency from OLED. The MLA was formed by first etching the silicon wafers using SF6 process gas in an RIE/ECR system using isotropic etching technique.The concave undercuts obtained after the dry etching was removed by wet-etching the wafer in HF and HNO3 solutions.Finally,the fabricated silicon mold was used to imprint the microlens structure on the PET substrates.The microlens array with 10 £gm and 25 £gm radius on PET substrate were successfully fabricated using the technique.The surface coverage of the MLA of beter than 90% was obtained. In addition,the outcoupling efficiency of an OLED can be increased using the MLA.The brightness enhancement factor of 1.67 was achieved using in the MLA comparision to the simulation result of 1.73.

This research reports a simple and novel method to fabricate microlens arrays by soft stamping the unexposed SU-8 photoresist. A SU-8 based stamp composed of micro-nozzle arrays with a reservoir structure on a glass substrate is first fabricated using a process of dosage control exposure. The unexposed SU-8 is then encapsulated in the cross-linked SU-8 shell and was used as the ¡§ink¡¨ for the stamping process. The proposed SU-8 microlens array is then formed by stamping the formed SU-8 structure on a bare glass substrate at a temperature higher than the glass transition temperature (Tg) of the unexposed SU-8 microlens array. Lenses with various radii of curvature can be formed by controlling the working temperature during the stamping process. In addition, this work also employed a simple electric static pulling scheme to manipulate the fabricated lenses profiles. Aspherical SU-8 microlens arrays with a wide range of tunable focal lengths were fabricated with this approach. Furthermore, we develop an advanced localize E-field control technique to fabricate microlenses with various focus length and microlenses with different tilt angle in a single lens array sheet. A novel grayscale mask fabrication technique is also proposed first. This low cost and rapid method is applied on stepwise and continuous tilt plane fabrication for produces a gradually changed E-field. Hetero axes and focus lengths microlenses are fabricated with this approach. In order to farther understand the real E-field distribution, a novel PCF based E-field sensor fabrication technique is also proposed. This technique also shows the potential on various PCF based devices fabrications.

Brightness enhancement film (BEF) has been manufactured in foreign factories for backlight module of liquid crystal display (LCD), then it only have some interior factories to put in exploitation. Because of this, the study presents a precision machining and new step-imprint hot embossing process to fabricate pyramid-shaped microlens array. First, a tungsten (W) steel material is manufactured by precision machining. The dimension of a pyramid-shaped microlens on the W steel are about 300 £gm in the base line of three side, 222 £gm in bevel edge of three side, 139 £gm in height of bottom to top, 180 £gm in pitch of the left and right sides between two pyramid-shaped microlens tips, and 85 degree in top angle of three bevel. The W steel mold is used as the first mold. Second, the pyramid peaks of first mold pattern are transferred on bulk metallic glass (BMG) using step-imprint hot embossing method with position adjustable mechanism to form a smaller concave pyramid-shaped microlens array, it can avoid arc radius of cutting tools which is used as the second mold. Another the pyramid peaks are transferred on PMMA (Polymethylmethacrylate) for concave pyramid-shaped microlens array of optical film in the hot embossing system. Finally, the second mold is fabricated to emboss convex pyramid-shaped microlens array of optical film on PMMA. The foregoing method is provided for backlight module of optical films process.

In this paper, we searched the parameter of BEF (Brightness enhancement film) using commercial FRED server for backlight module. The pattern analysis was carried out to understand its characteristic. The current structures used in LCD backlight are double-layer BEF. In addition, BEF of 3M takes the lion¡¦s share. But this may increase the thickness and cost of backlight module. In order to avoid those disadvantages, we tried to design single-layer BEF and characterize the effect through parameters study by using FRED software simulation. pyramid-shaped microlens array of BEF was constructed. Therefore, the effect of the variation of the structure parameters can be analyzed, such as prismatic degree (£c), prismatic structure on the brightness enhancement. It can be found from the result of simulation that the changes of the prismatic degree (£c) of 85 degree influence the brightness enhancement the most.

The primary focus of my work was to chemically functionalize diamond as normal and reversed phases for solid phase extraction (SPE) and high performance liquid chromatography (HPLC). Diamond was functionalized with -NH2 groups via self-limiting adsorption of an amine-containing polymer, polyallylamine (PAAm), onto oxidized diamond particles. The chemical stability of these particles was improved by thermal curing or chemical crosslinking with 1,2,5,6-diepoxycyclooctane. The reversed phase material for SPE was synthesized by reacting amine-functionalized diamond particles with long chain alkyl and a perfluorinated isocyanate. Unlike commercially available silica, functionalized diamond particles were stable under extreme pH conditions (pH 0-14). Functionalized diamond particles were used for SPE, although their lack of porosity resulted in poor analyte capacity. To create materials with greater surface area, core-shell diamond particles were synthesized via layer-by-layer deposition of PAAm and nanodiamond onto solid microdiamond. These particles had higher surface areas than solid diamond particles, and their application in SPE and HPLC was demonstrated. As a related project, I demonstrated microlens array patterning (MAP) for selective adsorption of PAAm during microarray fabrication. Initially, alkyl monolayer terminated silicon surfaces were photopatterned with thousands of wells using a microlens array. PAAm was then deposited in the presence of a cationic surfactant to limit nonspecific adsorption of PAAm. Finally, reactions of selectively adsorbed PAAm were shown with glutaric anhydride, phenylenediisothiocyanate, biotin NHS-ester and an oligonucleotide (DNA). My third project concerned the synthesis of an abrasion resistant hydrophobic coating on the surface of nylon and silicon oxide substrates using chemical vapor deposition (CVD) of two silanes. The synthesis consists of four steps: 1) plasma oxidation of the substrate, 2) treatment with 3-isocyanatopropyltrimethoxysilane, 3) exposure of the treated surfaces to water vapors, and 4) treatment with a perfluorinated silane to make the surfaces hydrophobic. The coating is not visible to the eye and does not change the feel of the surface. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry, contact angle goniometry, scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), Rutherford backscattering spectroscopy (RBS) and nuclear reaction analysis (NRA) were used to characterize the resulting materials.

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The development and application of portable LCD (Liquid crystal display) technology is the main trend on the market. The goal of this study is to fabricate a compound optical film, and we focus on the design and fabrication of a new type backlight module for side-LED (Light emitting diode) display. The optical efficiency can be improved via the compound optical film. The profile of optical film was determined using commercial optical software, FRED. The mold with multi aspect ratio and multi fill-factor microlens array by LIGA-like process (Lithographie galvanoformung abformung) was produced using THB-126N negative photoresist and AZ-4620 positive photoresist. The study presents many innovative processes, such as the homemade gray scale mask, and multi-step electroforming method, which both produces the microlens array with variable size and aspect ratio. In addition, the embedded micro-void caused light guide and diffusion under the quantitative control during the PDMS (Polydimethylsiloxane) optical film fabrication. The compound optical film with embedded micro-voids, multi aspect ratio and variable size microlens array can be fabricated quickly without substrate. Then the optical properties were analyzed by BM-7A to characterize the luminance, uniformity and optical efficiency.

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