Integration of stamper fabrication and design optimization of LCD Light guides using silicon-based microfeatures

• Published in: Microsystem technologies Vol. 16; no. 7; pp. 1193 - 1200
• Main Authors: Yu, Jyh-Cheng, Hsu, Pei-Kai
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.07.2010; Springer; Springer Nature B.V
• Subjects: Accuracy; Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Design optimization; Design parameters; Electroforming; Electronics; Electronics and Microelectronics; Electrooptical effects; Engineering; Etching; Exact sciences and technology; Geometry; Grooves; Illumination; Injection molding; Instrumentation; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Light emitting diodes; Mechanical Engineering; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Nanotechnology; Nickel; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Precision engineering, watch making; Prisms; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon; Silicon wafers; Simulation; Software; SOI (semiconductors); Technical Paper; Light Emit Diode; Fuzzy Inference Engine; Root Mean Square Error; Light Guide Plate; Anchor Point; Fuzzy logic; Anisotropic etching; Display devices; Electroforming; Silicon-on-insulator; Groove; Light emitting diodes; Liquid crystal devices; Silicon; Chemical etching; Optimization; Production process
• ISSN: 0946-7076; 1432-1858
• DOI: 10.1007/s00542-009-0948-5

This study applies a novel fabrication process that combines anisotropic wet etching of silicon-on-insulator (SOI) wafers with electroforming to manufacture precision stampers. Micron-sized features, such as trapezoidal grooves and truncated pyramidal prisms, can be fabricated and distributed accurately. Because feature geometry and distribution can be accurately realized using the proposed scheme, design optimization of light guide plates (LGPs) becomes realistic. By observing the illumination characteristics of light emitting diode (LED) edge-lit LGPs, the distribution pattern of the LGP is transformed into a parameter design with seven anchor spacing and the spacing modulation amplitude of the micro features adjacent to LEDs. The proposed fuzzy optimization scheme manipulates distribution parameters to obtain an LGP design with high illumination uniformity. The design of a 3.5-inch LED edge-lit LGP is used as an illustrative example. The optical software program TracePro is applied to simulate luminance performance of BLM. The optimization converges rapidly and provides the optimum design with an average brightness of 2,266 (nit) and uniformity of 90% without use of diffusive sheets. Thus work demonstrates the feasibility and effectiveness of the proposed scheme.