Jae-Beom Choi

32.2: Touch-Panel Controller Implemented with LTPS TFTs

A touch panel controller has been implemented with LTPS TFTs on a glass substrate. It induces voltage gradient across either plate of a 4-wire resistive touch panel and senses the intermediate potential at the touch position via the other plate. Then it converts the acquired analog voltage into digital signal and outputs 3-bit digital data for the horizontal and vertical positions respectively.

28.3: World's Largest (21.3 in.) UXGA Non‐Laser LTPS AMLCD

We have successfully demonstrated a 21.3-inch UXGA (1600 × RGB × 1200) LTPS AMLCD manufactured by non-laser crystallization method. The gate and data drivers were made of CMOS TFTs. Gate-driver circuits composed of shift registers and buffer circuits were integrated on both sides of panel for dual driving method and the multiplexing circuit was implemented on its data circuits. The non-laser technique such as nanocap-assisted crystallization is promising for low-cost LTPS on glass, compared to conventional laser annealing process.

P‐8: a‐Si:H TFT‐LCD with Single Organic Passivation Layer

A novel photosensitive organic material is used as the single organic passivation layer for the conventional back channel etched thin film transistors. We find that the leakage current of the a-Si:H TFTs with single organic passivation layer is lower than that of the conventional transistors with silicon nitride passivation layers and the adhesion strength between the organic layers and the pixel electrode is sufficiently strong so that the overlap between the ITO pixel electrode and the data lines can be formed. Using the novel materials, 1.9″ qCIF AMLCD with single organic passivation layer was successfully fabricated with reduced process steps.

P-31: Thin and Light Integrated TSP with Enhanced Display Qualities

We have developed an innovative liquid crystal display (LCD) which includes a resistive type touch screen system — integrated touch screen panel (iTSP). It can detect touch events and locate touch positions by measuring voltage at the contact point between indium tin oxide (ITO) coated color filter glass and ITO conductive isotropic film. iTSP shows not only better display qualities outside but also considerable decreases in weight and thickness compared to conventional resistive touch screen panel which consists of ITO glass and conductive film. In this paper, main characteristics of 7.0″ WVGA LCD Panel integrated with the touch screen function were presented and the optical characteristics also were discussed.

35.2: Development of 3″ VGA LCD for DSC Application

3″ video graphic array (VGA) liquid crystal display (LCD) for digital still camera (DSC) has been developed using new driving method and fine process. This VGA panel can be driven by conventional standard interface which is widely used for 230K dots LCD. The fine process enabled us to design patterned vertical alignment (PVA) pixels with 50 % aperture ratio. It is expected that the high quality display can be realized by the technologies developed for the VGA DSC panel.