Din-Guo Chen

Development of Anti-Reflection (AR) Coating on Plastic Panels for Display Applications

Traditionally, various vacuum-based processes have been used for producing interference-type anti-reflection (AR) coatings on large area substrates for different commercial applications. In this paper, the development of sol-gel derived AR coating on large plastic substrates for display application is presented. The sol-gel dip coating process was used to deposit thin films on large size plastic panels. By developing sols with different refractive indices, multi-layer thin-film AR coating stacks were designed and fabricated. These coatings possess good uniformity and meet stringent automotive specifications. This technology has been commercialized successfully for dashboard instrument panel application in Toyotas new hybrid engine car, named Prius.In this paper, AR coatings prepared by the sol-gel process are reviewed. The basic design concept for an AR coating, the coating preparation procedure, and important parameters of the solution coating process are discussed. Optical constants of the coating materials were characterized by using spectroscopic ellipsometry. Optical, mechanical and environmental tests were performed on the sol-gel derived AR coating stack. The sol-gel derived AR coating possesses equivalent or superior properties when compared to the major commercially available AR coating products.

Microstructural evolution of titania sol-gel thin films

Thin films of crystalline titania with different grain sizes and porosities were prepared by dip-coating on Si (100) substrates starting from a sol-gel process. Three synthesis procedures were developed and compared, using acetylacetone (acac, with HCl) and acetic acid (HOAc) as modifying agents or directly using hydrochloric acid as catalyst. The structural evolution of the films was characterized by Glazing Angle X-ray Diffraction (XRD), Spectroscopic Ellipsometry and Atomic Force Microscopy (AFM). Anatase phase was observed on all of the films calcined at 440 C. The grain sizes and crystallinity generally increased with calcination temperature. Thin films obtained from acac and HOAc-modified titanium sols had fine grains (50--80 nm) and less porosity (<10%) after calcination at 1,000 C. Thin films derived from the sol catalyzed directly with acid had the largest grains (90--130 nm), higher crystallinity and greater porosity (17%).

50.4: Anti‐Reflection (AR) Coating on Plastic Panels for Display Applications

Traditionally, various vacuum-based processes have been used for producing interference-type anti-reflection (AR) coatings on large area substrates for different commercial applications. In this paper, the development of sol-gel derived AR coating on large plastic substrates for display application is presented. The sol-gel dip coating process was used to deposit thin films on large size plastic panels. By developing solutions with different refractive indices, multi-layer thin-film AR coating stacks were designed and fabricated. Optical constants of the coating materials were characterized by using spectroscopic ellipsometry. Optical, mechanical and environmental tests were performed on the sol-gel derived AR coating stack. These coatings possess good uniformity and meet stringent automotive specifications. This technology has been commercialized successfully for dashboard instrument panel application in Toyota Prius, a new hybrid car. The sol-gel derived AR coating possesses equivalent or superior properties when compared to the major commercially available AR coating products. These AR coated panels are also useful for other commercial applications.

Synthesis and Intermolecularly Mediated Assembly of Organic Pigment in Hybrid Coating Films

The insoluble, strongly hydrogen bonded organic pigment of 3,6-bis-(4-chlorphenyl)-l,4- diketopyrrolo [3,4-c] pyrrole was transiently blocked by adding carbamate groups, and consequently incorporated into organic-inorganic hybrid matrices by a sol-gel process. The homo- (pigment-pigment) and hetero-intermolecular (pigment-matrix) interactions were found to control both the assembly and dispersion of pigment molecules in the hybrid coating films. A weaker interaction between matrices and pigment molecules results in aggregation of the carbamate pigment in the methyl-silicate films. A stronger interaction forms a homogenous dispersion and coloration of the phenyl-silicate films. The as-prepared methyl- and phenylsilicate films doped with the organic pigment were distinguished by a morphology change and a blue (hypsochromic) shift in absorption from 550 to 460 nm. Thermal treatment can remove the carbamate groups and in-situ form the organic pigment in the hybrid films.