• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1168-1171
• /
• 2007

Integrating systems on TFT-LCD panels is more and more popular for the mobile display application. However, it may not be necessary to use LTPS TFT devices. A-Si TFTs are used to integrate systems on TFT-LCD panels, especially scan (gate) drivers. To further reduce the chip size of driver IC, the triplegate pixel structure is developed. Therefore, the number of the source lines is reduced to 1/3 times.

• Proceedings of the KIEE Conference
• /
• 2005.11a
• /
• pp.125-129
• /
• 2005

Mobile display는 사용자가 이동하면서 화면을 보기 때문에 주변 luminance의 변화에 따라서 contrast ratio 변화가 심하다. 특히 햇빛 아래에서는 Mobile display의 화면을 알아보기 어렵다. 본 연구에서는 주변 조도가 증가할수록 TFT LCD의 black 휘도의 변화율이 white 휘도 변화율보다 크게 작용하여 전체 contrast ratio(이하 CR)가 크게 감소함올 확인하였다. 또한, 반투과형 LCD는 반사창을 통해서 외부 빛올 반사시키기 때문에 주변 조도가 높아도 일정 수준의 CR은 유지할 수 있다. 그러나 투과형 LCD보다 CR이 낮았다. 본 논문에서는 투과형 TFT LCD에 back light 광원으로 LED를 사용하고, photo diode와 LED drive IC를 이용하여 주변 조도의 광량에 따라서 LCD의 back light LED의 휘도를 3단계 조절할 수 있는 회로를 구성하였다. 이렇게 함으로써 주변 조도에 따라 자동으로 back light 휘도 조절이 가능한 결과을 얻었다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.39-42
• /
• 2003

Low temperature polysilicon (LTPS) TFT LCOs are in production today at sizes ranging from 0.33" for Viewfinders to 17" for LCD TVs with 21.3" recently demonstrated. Because of their form factor, resolution, brightness and other benefits, LTPS TFT LCD unit shipments, revenues and capacity are expected to grow rapidly, particularly for mobile applications. However, despite the strong outlook, LTPS TFT LCOs are still faced with numerous challenges from a market and technology perspective. LTPS TFT LCD producers were surveyed on which of the current challenges were the most problematic among other questions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.540-543
• /
• 2007

In this paper, we propose a new approach to reduce the audible noise generated by TFT-LCD module in mobile applications. We also analyzed impact factors which effect on the audible noise. It is expected that this noise source comes from various impact factors such as vibration of flexible printed-circuit board (FPCB) and LCD panel, and static electricity charged in window and back-light unit. Windowless type and window type models are evaluated to analyze noise level due to the static electricity charged in window. To obtain reliable and reproducible data, we constructed controllable test jig and measurement set-up.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.6B
• /
• pp.630-640
• /
• 2009

The thesis suggests hand-held equipment to overhaul for mobile TFT LCD/OLED module of high-performance. The established module equipment to overhaul could distinguish outputting video data to module for distinguishing flicker, but it is impossible with low system. In this thesis, supporting system could check the various supplement functions from bringing equipment to overhaul without changing design of FPGA or H/W the module various size for equipment to overhaul for module of high-performance coincidently. The system includes hand-held equipment to overhaul, test software embedded and software a base personal computer and have designed to output, save, and certify all contents of module test of hand-held equipment to overhaul to interface universal serial bus. Setting up 9 items that represent for efficient verification of the proposed system have been possible confirmation with TFT LCD/OLED module of high-performance, establishment scan time, creation gamma, changing register, supporting interface, and multi inch modules.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.489-493
• /
• 2005

TFT-LCD(Thin Film Transistor Liquid Crystal Display) module is representative commercial product of FPD(Flat Panel Display). Thickness of TFT-LCD module is very thin. It is adopted for major display unit for IT devices such as Cellular Phone, Camcorder, Digital camera and etc. Due to the harsh user environment of mobile IT devices, it requires complicated structure and tight assembly. And user requirements for the mechanical functionalities of TFT-LCD module become more strict. However, TFT-LCD module is normally weak to high level transient mechanical shock. Since it uses thin crystallized panel. Therefore, anti-shock performance is classified as one of the most important design specifications. Traditionally, the product reliability against mechanical shock is confirmed by empirical method in the design-prototype-drop/impact testredesign paradigm. The method is time-consuming and expensive process. It lacks scientific insight and quantitative evaluation. In this article, a systematic design evaluation of TFT-LCD module for mobile IT devices is presented with combinations of FEA and testing to support the optimal shock proof display design procedure.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.968-971
• /
• 2009

TFT-LCD display system is nowadays one of power-hungry components in portable products; technique of power reduction is thus essential for production of mobile phone. In this work, we minimize the display power, using computationally intelligent statistical methodology. Compared with a conventional design, 68.474% reductions on the current consumption could be obtained for a 2.2-inch of TFT-LCD display system of mobile phone. The total power consumption of the display system consisting of the backlight system and current consumption of display panel is thus successfully reduced form 68.305mW to 64.06mW (about 6.215% reductions).

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.6
• /
• pp.31-38
• /
• 2009

To improve the image quality and lower the power consumption of the mobile applications, it is the one of the best candidate to control the backlight unit of the LCD module with ambient light. Ambient light sensor and readout circuit were integrated in LCD panel for the mobile applications, and we designed them with LTPS TFT. We proposed noble start-up correction in order to correct the variation of the photo sensors in each panel. We used time-to-digital method for converting photo current to digital data. To effectively merge time-to-digital method with start-up correction, we proposed noble dual slope correction method. The entire readout circuit was designed and estimated with LTPS TFT process. The readout circuit has very simple and stable structure and timing, so it is suitable for LTPS TFT process. The readout circuit can correct the variation of the photo sensors without an additional equipment, and it outputs the 4-levels digital data per decade for input luminance that has a dynamic range of 60dB. The readout rate is 100 times/sec, and the linearity error for digital conversion is less than 18%.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.249-249
• /
• 2000

This paper introduces a clean mobile robot fur 4th generation LCD cassette, which is guided by optical sensor and position compensation using vision module. The mobile robot for LCD cassette transfer might be controlled by AGV controller which has powerful algorithms. It offers optimum routes to the destination of clean mobile robot by using dynamic dispatch algorithm and MAP data. This clean mobile robot is equipped with 4 axes fork type manipulator providing repeatability accuracy of $\pm$ 0.05mm.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.47 no.1
• /
• pp.17-28
• /
• 2010

This paper presents a new automatic TFT-LCD image quality optimization system using DSP for the first time. Since conventional manual method depends on experiences of LCD module developers, it is highly labor-intensive and requires several correction steps providing large gamma correction error. The proposed system optimizes automatically gamma adjustment and power setting registers in mobile TFT-LCD driver IC to reduce gamma correction error, adjusting time, and flicker. It contains module-under-test (MUT, TFT-LCD module), PC installed with program, multimedia display tester for measuring luminance and flicker, and control board for interface between PC and TFT-LCD module. We have developed a new algorithm using 6-point programmable matching technique with reference gamma curve and applying automatic power setting sequence. Developed algorithm and program are generally applicable for most of the TFT-LCD modules. It is realized to calibrate gamma values of 1.8, 2.0, 2.2 and 3.0, and reduce flicker level. The control board is designed with DSP and FPGA, and it supports various interfaces such as RGB and CPU. Developed automatic image quality optimization system showed significantly reduced gamma adjusting time, reduced flicker, and much less average gamma error than conventional manual method. We believe that the proposed system is very useful to provide high-quality TFT-LCD and to improve developing process using optimized gamma-curve setting and automatic power setting.