• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.713-716
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• 2008

This paper presents an automatic back-light brightness control system for mobile displays. One of the most important factors in mobile display is the power consumption due to the limited and movable power source. More than 80% of power of the LCD display is consumed by LED bark-light unit (BLU). The target brightness also becomes higher because of its moving picture and high resolution image, so there are some side effects for not only excessive power consumption but also ergonomic inconvenience in dark environment. To prevent this discomfort and reduce power consumption, this paper proposes automatic brightness control (ABC) technique in mobile displays. Developed system contains TFT-LCD panel with built-in photo sensor, driver IC capable of controlling photo sensor, and BLU. Since the photo sensor array built in panel detects automatically outdoor ambient light intensity, the power of BLU in dark environment is reduced. Developed ABC system showed reduced power consumption of 50% in dark environment. We believe that the proposed system is very useful to control power of mobile TFT-LCD.

• Journal of the Korean Applied Science and Technology
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• v.27 no.2
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• pp.137-143
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• 2010

Oxide semiconductors Thin-film transistors are an exemplified one owing to its excellent ambient stability and optical transparency. In particular zinc oxide (ZnO) has been reported because It has stability in air, a high electron mobility, transparency and low light sensitivity, compared to any other materials. For this reasons, ZnO TFTs have been studied actively. Furthermore, we expected that would be satisfy the demands of flexible display in new generation. In order to do that, ZnO TFTs must be fabricated that flexible substrate can sustain operating temperature. So, In this paper we have studied low-temperature process of zinc oxide(ZnO) thin-film transistors (TFTs) based on silicon nitride ($SiN_x$)/cross-linked poly-vinylphenol (C-PVP) as gate dielectric. TFTs based on oxide fabricated by Low-temperature process were similar to electrical characteristics in comparison to conventional TFTs. These results were in comparison to device with $SiN_x$/low-temperature C-PVP or $SiN_x$/conventional C-PVP. The ZnO TFTs fabricated by low-temperature process exhibited a field-effect mobility of $0.205\;cm^2/Vs$, a thresholdvoltage of 13.56 V and an on/off ratio of $5.73{\times}10^6$. As a result, We applied experimental for flexible PET substrate and showed that can be used to ZnO TFTs for flexible application.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.205-207
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• 2009

LCD (liquid crystal display) industry is needed to goods of high reliability and is interested in products without harmful material. In this experiment, we made the LED backlight unit for Automotive-navigation. And for making this backlight unit we used to eight side emitting type white LEDs with 1W high power of the lumileds company. We could know that this backlight unit releases to 6500 nit in 14W power consumption and start up voltage time is under the15ms in the ambient temperature -20 $^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.220-222
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• 2003

In this paper, we analyze on the discharge characteristics through 1-D simulations in an at plasma display panel discharge cell. The model is based on a Poisson' equation, continuity and drift-diffusion equation. Results are presented in a 95% neon, 5% xenon gas mixture, for a gap length of 100us and a gas pressure of 400Torr at ambient temperature. Results for other gap length are also discussed. As a result, an increase of the gap cause increase of luminous efficiency but with larger sustaining voltage.

• Journal of Computing Science and Engineering
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• v.3 no.4
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• pp.218-237
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• 2009

Interactions are intrinsic part of what we do. We interact when we work, when we learn, when we visit a doctor, and when we play. With the advent of information and communications technology we can collect rich data (video, audio, and various transcripts including text chat) about such interactions. This opens an opportunity to monitor the dynamics of interactions and to get deeper insights of how they unfold and deliver this information to the interacting parties. This paper presents the design of a technology for visualising information about the dynamics of unfolding of interactions and presenting it in an ambient display on mobile devices. The purpose of this technology is the delivery of such information to the point of decision making.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1443-1446
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• 2007

The luminance and operating voltage were measured during OLED operation for the purpose of analyzing the efficiency and change of internal resistance. The half lifetime of OLED was affected by degradation of OLED due to heat generated by ambient temperature and self heating. The operating voltage constantly increased due to the increase of internal resistance. The half lifetime of OLED driven by constant current source was found to be longer than that of the OELD driven by constant voltage and the reasons were clearly explained in this paper.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.354-359
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• 2007

유비쿼터스 컴퓨팅 환경으로 변화됨에 따라 사용자의 묵시적인 행위에 따라 반응하면서도 주의를 지나치게 집중시키지 않는 다양한 디스플레이에 대한 요구가 증가되고 있다. 본 논문에서는 액자형 앰비언트 디스플레이 시스템을 이용하여 사용자의 위치에 따라 사진을 내비게이션 하는 방법을 제안한다. RFID 센서와 초음파 센서를 이용하여 사용자 신원 및 디스플레이와의 접근거리를 인식하고, 사용자와 디스플레이의 근접도에 따라 보여 질 영상과 인터페이스의 상세도 레벨을 자동으로 정하게 된다. 사용자가 디스플레이로부터 아주 멀리 있는 경우에는 주의를 집중시키지 않도록 단순한 그림 액자의 기능을 제공한다. 사용자가 인터랙션 가능한 영역으로 진입하면 사용자와 관련된 사진을 보여주고, 사용자의 위치에 따라 TIP(Tour Into the Picture) 방법을 이용하여 사진을 3 차원 내비게이션 할 수 있도록 하였다. 또한 터치 스크린을 이용한 메뉴의 직접적인 조작과 공중 마우스를 이용한 원격 메뉴 조작 또한 가능하도록 하였다. 뿐만 아니라 댁내의 응급 상황 정보 등을 전달 할 수 있도록 디스플레이 프레임 주위를 LED 를 이용하여 반짝일 수 있도록 설계 하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1086-1089
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• 2006

We have developed 2.4" QVGA wide color gamut LCD module using RGB-LED backlight. The color gamut is achieved 100% of NTSC compared to 70% of NTSC when used with White-LED backlight. But RGB LED backlight is difficult to maintain its color balance since RGB LED is gradually degraded by the change of ambient temperature and a long term aging characteristic, etc. This paper describes a feasibility study of our optical feedback system developed for preventing such a color shift.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.849-851
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• 2003

After multi-walled carbon nanotubes (MWNT) powder was crushed with ball milling process, it was mixed with organic vehicles. And then CNT paste was printed on ITO coated glass substrate. The field emission characteristics of CNT pastes fired in air atmosphere was better than that of CNT paste fired in Ar ambient due to less organic residues after firing.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.141-142
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• 2000

In order to improve electron field emission and its stability, tip surface of amorphous silicon field emitters have been coated with molybdenum layer with a thickness of 25 nm through the gate opening and annealed rapidly in inert ambient. Compared with amorphous silicon field emitters, Mo silicidized amorphous silicon field emitters exhibited lower turn on voltage about 9 V, 3.8 times higher maximum current, 3.1 times lower fluctuation range and less change of the emission current depending on the vacuum level.