• Journal of Information Display
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• 제6권3호
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• pp.18-21
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• 2005

A new technology for reducing photolithography process from a four step to a three step process in the fabrication of TFT LCD is introduced. The core technology for 3-mask-TFT processes is the lift-off process [1], by which the PAS and PXL layers can be formed simultaneously. A different method of the lift-off process was developed in order to enhance the performance of efficiency with conventional positive and not negative PR which is the generally used in other lift-off process. In addition, the removal capacity of the ITO/PR in lift-off process was evaluated. The evaluation results showed that the new process can be run in conventional TFT production condition. In order to apply this new process in existing TFT process, several tests were conducted to ensure stability of the TFT process. It was found that the outgases from PR on the substrate in ITO sputtering chamber do not raise any problem, and the deposited ITO film beside the PR has conventional ITO qualities. Furthemore, the particles that were produced due to the ITO chips in PR strip bath could be reduced by the existing filtering system of stripper. With the development of total process and design of the structure for TFT using this technology, 3-mask-panels were achieved in TN and IPS modes, which showed the same display performances as those with the conventional 4mask process. The applicability and usefulness of the 3-mask process has already verified in the mass production line and in fact it currently being used for the production of some products.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1507-1509
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• 2005

LCD(Liquid Crystal Display) products is needed to have high reliability and are produced without harmful material. Because Substitution for CCFL of Light source used to Conventional backlight unit, research is going about product with LED of light source at present. In this experiment, We made the LED backlight unit with high quality for automotivenavigation. This backlight unit has center luminance of 6500 nit at15W power consumption. We adjusted chromaticity by using ten Blue LED and eight side emitting type White LEDs with high power LED from Lumileds company.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.17-18
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• 2006

Flat Panel Displays (FPDs) have made a revolution in the display industry. TFT-LCD (Thin Film Transistor Liquid Crystal Display) has been the main player of FPD for last two decades. As the industry continuously develops the technology for better performance with lower cost is constantly demanded where several post LCD technologies are being developed. One of the prime candidates of post LCD technology is AMOLED (Active Matrix Organic Light Emitting Diode) that is considered to be an ideal FPD due to its extraordinary display performance and potentially low cost display structure. This technology has been accepted to small size display applications, such as cellular phone, PDA and PMP, etc. In this paper it is discussed that how this technology can be extended to large size display applications, such as TV. The technical issues and solutions of TFT backplane and color patterning of OLED materials are discussed and proposed

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.962-964
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• 2007

A 14.1-inch reflective type Thin Film Transistor-Electric Phoretic Display was developed at the esolution of 1280 x 900 lines on plastic substrate. All of the processes of TFT were carried out below $100\;^{\circ}C$ on PES plastic films. The process conditions of TFT were optimized for large area TFT-LCD on plastic substrate. At $60^{\circ}C$ high temperature during 160hours, TFT does not delaminate and IV characteristic is also satisfied.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.463-465
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• 2006

We have developed the VIC (Viewing-angle Image Control) TFT-LCD, which can change viewing-angle from $80^{\circ}$ to $170^{\circ}$. This display has the same thickness and weight as existing TFT-LCD, because it is made of only single LC cell without additional components. Moreover, we developed ways to protect effectively the displayed information in narrow viewing angle mode.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.317-320
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• 2005

We report experimental and simulation results of L0 state using inner retarder film compared with normal retardation film. In short wavelength range, the reflectance of inner retardation film is three times compared with that of normal retardation film. This results in blue color of L0 state, as retardation decreases or polar angle increases, the color shifts toward purple, finally yellow color, as expected in the simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.125-129
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• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.489-493
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• 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
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.46-49
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• 2002

Recent trends of low-temperature polycrystalline Si (LTPS) TFT technologies are presented. Characteristics of LTPS TFT processes are compared with those of a-Si TFT's. In order to compete with well-established a-Si TFT-LCD technology, LTPS process has to be as simple as possible. One of the most critical processes, recrystallization of a-Si thin films, could be the process for the differentiation of LTPS technology. Along with these technical reviews, a recent development of the 5.0-inch LTPS TFT-LCD is presented. In order to achieve high-performance display characteristics and save the power consumption, the transflective mode is adopted. The 5.0-inch display with 186 pixel-per-inch, high-resolution LCD was measured to be 10% for the reflectance and 70:1 for the contrast ratio. This display is designed for a high information content hand-held PC (HHPC) application.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.401-404
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• 2002

We have studied on response time of the fringe-field switching (FFS) TFT-LCD using the LCs with negative dielectric anisotropy related to rubbing angle. Simulation and experimental results shows that when a rubbing angle approached $45^{\circ}$, a slope of voltage-dependent curve is decreased such that the operation voltage is increased, however the whole response characteristic between inter-gray levels have a trend to be fast.