In-Byeong Kang

Coplanar amorphous-indium-gallium-zinc-oxide thin film transistor with He plasma treated heavily doped layer

We report thermally stable coplanar amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) with heavily doped n+ a-IGZO source/drain regions. Doping is through He plasma treatment in which the resistivity of the a-IGZO decreases from 2.98 Ω cm to 2.79 × 10−3 Ω cm after treatment, and then it increases to 7.92 × 10−2 Ω cm after annealing at 300 °C. From the analysis of X-ray photoelectron spectroscopy, the concentration of oxygen vacancies in He plasma treated n+a-IGZO does not change much after thermal annealing at 300 °C, indicating thermally stable n+ a-IGZO, even for TFTs with channel length L = 4 μm. Field-effect mobility of the coplanar a-IGZO TFTs with He plasma treatment changes from 10.7 to 9.2 cm2/V s after annealing at 300 °C, but the performance of the a-IGZO TFT with Ar or H2 plasma treatment degrades significantly after 300 °C annealing.

A Fast and Energy Efficient Single-Chip Touch Controller for Tablet Touch Applications

In tablet touch applications, fast sensing is essential to enhance reporting rate and low power consumption is also essential to prolong battery life. To satisfy both essential demands, a fast and energy efficient single-chip touch controller for medium size (7 to 11.6 inch) of capacitive touch screen panels (TSP) is presented. The presented touch controller is designed with fast sensing methods which are proposed to enhance reporting rate and to reduce power consumption. In this paper, the proposed fast sensing methods are described in detail with their implementation and experimental results. The presented touch controller consumes power of 47.50 mA at 10.1 inch TSP, providing the minimum reporting rate of 129 Hz under 10 simultaneous touches.

25.4L: Late‐News Paper: A Novel Polarizer Glasses‐Type 3D Displays with an Active Retarder

In this paper, we suggested a novel method achieving high resolution and high brightness in the glasses-type 3D displays and fabricated a prototype of 15″ size in diagonal, which is composed of an active retarder synchronized with an image panel. The active retarder is configured to a TN mode to have a function of polarization switching for the input polarization states. We expect that the AR3D technology can give high resolution and high brightness for the 3D users with a convenience of simple polarizer glasses and an inexpensive cost compared with the shutter glasses type 3D display, where not only the image panel and but also the glasses should have an LCD panel.

Flexible Display Technology – Opportunity and Challenges to New Business Application

Flexible displays have attracted much attention because they will be the key to open the next generation display market in the ubiquitous era. Many progressive prototypes of the flexible e-papers and the flexible AMOLEDs enable to have expectation that the early product of the flexible display will come into the market in the near future. In addition, it is expected that the remarkable development of the printing technologies and the organic electronics can realize the rollable, extremely low price, and even disposable displays. In this paper, the prospect of the flexible display, the technical issues, and the R&D status are briefly reviewed.

14.4: Integrating Multi-Touch Function with a Large-Sized LCD

Multi-touch function is integrated with a 52″ LCM. IR image sensors detect touches around normal panel. A few IR image sensors are placed to detect touches. Triangulation, image processing technology and pattern recognition are used for touch algorithm. Positions of touch points are calculated simultaneously by using IR image sensors, IR light sources and a LCD panel. The number of touches and its area is used to perform multi-touch functions. Multi-touch LCD can also detect human gestures. At this work, map searching program is used for touch and gesture recognition. As a result, multi-touch LCD shows its usefulness and it can replace conventional HCI device (mouse, keyboard).

15.4: A Novel High Speed Integrated Gate Driver Circuit using a-Si TFT for 240Hz FHD LCD TVs

A novel high speed integrated gate driver using a-Si TFT for large size 240Hz FHD TFT-LCD TVs has been developed. The proposed circuit architecture achieved high speed operation by means of separating control signal from output signal and double buffer. Two channel shared node structure also reduce the area of the circuit without performance degradation, while the life time of the integrated gate driver is estimated to more than 50,000 hours. Thus we successfully developed the true 240Hz FHD TFT-LCD panel using 1G-1D driving method with this integrated gate driver

A study of roll-printing technology for TFT-LCD fabrication

— Recently, potential breakthrough technologies for low-cost processing of TFT-LCDs and new process developments for flexible-display fabrication have been widely studied. A roll-printing process using etch-resist material as a replacement for photolithographic patterning was investigated. The characterization of the properties of patterns formed in roll printing, a method to fabricate cliche plates for fine patterns, and the design of a new formulation for resist printing ink is reported. The pattern position accuracy, which is one of the most important issues for the successful application of printing processes in display manufacturing was studied and how it can be improved by optimizing the blanket roll structure is explained. New design rules for the layout of the thin-film-transistor array was derived to improve the compatibility of roll printing. As a result, a prototype 15-in.-XGA TFT-LCD panel was fabricated by using printing processes to replace all the photolithographic patterning steps conventionally used.

4.4L: LateNews Paper: A Novel High Reliable Integrated Gate Driver with BiScanning Structure using aSi TFT for Large Size FHD TFTLCD TVs

A novel integrated gate driver with biscanning structure using a Si TFT for large size FHD TFTLCD TV has been developed. The proposed gate driver has biscan control circuit which enables reverse scanning operation and TFT stress reduction circuit which enhances gate driver reliability for TV application. Two channel shared node structure also reduce the area of the circuit without performance degradation, while the life time of the integrated gate driver is estimated to 100,000 hours. Thus we successfully developed 47 inch FHD 120Hz TFTLCD panel with this integrated gate driver circuit using aSi TFT.

Formation of the overcoat layer and column spacer for TFT-LCD using capillary force lithography

The column spacer and overcoat layer of the color filter substrate for liquid crystal displays formed at once by capillary force lithography was studied using UV-replica mold and UV-curable liquid resin. The low viscosity and rapid curing speed of the liquid resin make it possible to pattern successfully in the industry application. We can estimate the coating thickness in order to achieve desired overcoat thickness according to mass balance. The formed overcoat layer and column spacer exhibited both satisfied transmittance and recovery ratio for liquid crystal display as commercial these for photo-lithography method. Finally, we demonstrated the panel using this technique and material. This work can provide a possibility for simply and low-cost process to form a functional layer in display.

P-185L: Late-News Poster: Direct Patterning of Metal Electrodes for TFT-LCD Fabrication

We have analyzed a metal direct printing method using roll printing technology for the low cost process in TFT-LCD fabrication. The silver metal electrodes patterned down to 3 μm in space width between lines were directly printed by this method. Very low line resistivity of 4.5 μΩ⋅cm was obtained, which is comparable to that of the AlNd metal alloy for the gate electrode of TFT-LCD. Furthermore, we evaluated the transfer characteristics of an a-Si:H TFT using directly printed silver material as a gate line.