SLS crystallization and CMOS LTPS process have been developed for high performance and uniform characteristics. By strictly optimizing SLS optics in conventional 2 shot SLS process, threshold voltage variation of 720 pixel TFTs in 2.2‐inch QVGA panel (240×RGB) was remarkably decreased from 1.89 V to 0.56 V of 3sigma value. Mobility of the channel doped NTFT and PTFT for circuits were 146 and 38 cm2/Vs, respectively. Functional unit circuits for SOG were also fabricated and properly operated.

A reflective color TFT‐LCD with high image quality has been developed for mobile display tools. The optimized construction of normally white (NW) mode reflective twisted hybrid aligned nematic (RTHAN) cell with a single polarizer and the cell structure is the same as the conventional sandwich 90° TN cell. The productivity of the generation of low pretilt angle is achieved by the proposed single exposure method. In this work, we have studied an optical design of the reflective twisted HAN mode TFT‐LCD to research an optical element design to obtain high contrast ratio, fast response time, wide viewing angle, and low driving voltage.

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We have developed a new vertical alignment mode that uses a valley or hole as a source of moving liquid crystal when the voltage is applied. As the valley or hole can be made by the same process steps as the TN color filter, this new VA mode can be manufactured by the simplest process steps than any other TFT-LCD modes. We also have found that liquid crystal aligns parallel to the surface of the valley or hole when the voltage is applied. Finally, the electro-optic characteristics of this mode are studied with various parameters such as the birefringence and pitch of liquid crystal.

A new method to form polycrystalline silicon film with large grains at the controlled location by using a single irradiation of excimer laser beam is proposed for polycrystalline silicon thin film transistor. The excimer laser beam is modified to have a spatial intensity profile -periodic spatial variation of intensity maxima (I Max ) and minima (I Min ) -by the specially designed mask composed of the opaque and the transparent patterns where the opaque pattern size is less than the optical resolution of projection lens. Based on the melt depth of amorphous silicon at the location of I Min , one can obtain three different regimes, namely, the partial melting, the near-complete melting, and the complete melting. Polycrystalline silicon grains grow vertically and laterally from the seeds at the location of I Min to the complete molten region of I Max . The evolution of polycrystalline silicon microstructure is investigated and elucidated in each regime.