• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.646-648
• /
• 2003

The electrical and optical characteristics of the cold cathode fluorescent lamps (CCFL) were measured and investigated under the wide ambient temperatures ranging from $-30^{\circ}C$ up to $+100^{\circ}C$. The highest luminous efficiency of the CCFL of 55 lm/W was obtained at the ambient temperature of $50^{\circ}C$.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.11
• /
• pp.48-55
• /
• 2016

Ambient-light sensor system, which changes the brightness of a display as ambient light change, was studied to reduce the power consumption of the mobile applications such as note PC, tablet PC and smart phone. The ambient-light sensor system should be integrated on a display panel to improve the complexity and cost of mobile applications, so the ambient-light sensor and readout circuit was integrated on a display panel using low-temperature poly-silicon thin film transistors (LTPS-TFT). We proposed the new compensation method to correct the panel-to-panel variation of the ambient-light sensors, without additional equipment. We designed and investigated the new readout circuit with the proposed compensation method and the analog-to-digital converter for the final digital output of ambient light. The readout circuit has very simple structure and control timing to be integrated with LTPS-TFT, and the input luminance ranges from 10 to 10,000 lux. The readout rate is 100 Hz, and maximum differential non-uniformity with 20 levels of the final output below 0.5 LSB.

• Journal of the Korean Physical Society
• /
• v.73 no.9
• /
• pp.1329-1333
• /
• 2018

We investigated the mechanism of mobility enhancement after the dehydrogenation process in polycrystalline silicon (poly-Si) thin films. The dehydrogenation process was performed by using an in-situ CVD chamber in a $N_2$ ambient or an ex-situ furnace in air ambient. We observed that the dehydrogenated poly-Si in a $N_2$ ambient had a lower oxygen concentration than the dehydrogenated poly-Si annealed in an air ambient. The in-situ dehydrogenation increased the (111) preferred orientation of poly-Si and reduced the oxygen concentration in poly-Si thin films, leading to a reduction of the trap density near the valence band. This phenomenon gave rise to an increase of the field-effect mobility of the poly-Si thin film transistor.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.7
• /
• pp.525-529
• /
• 1999

The influence of ambient gases on field emission performance of Mo-field emitter array(FEA) in the frit-sealing step of field emission display(FED) packaging process was investigated. Mo-tip FEA was mounted on the glass substrate having a surrounded frit(Ferro FX11-137) and fired at $415^{\circ}C$ in the ambient gases of air, $N_2$ and Ar. The Ar gas was proved to be most proper ambient among the used gases through evaluating the turn-on voltage and field emission current of the fired Mo-tip FEA devices. It was confirmed that the Mo surface fired in Ar ambient was less oxidized when compared with another ones annealed in air and Ar ambient by the AFM, XPS, AES and SIMS analysis. Finally, the 3.5 inch-sized Mo-tip FED, which was packaged using frit-sealing process in the Ar ambient, was proposed.

• Journal of Information Display
• /
• v.4 no.4
• /
• pp.25-32
• /
• 2003

One of the important problems in ac PDP in recent years is the misfiring of ac PDP at high ambient temperatures which consequently degrades the image quality of the ac PDP. This may be due to the change of working gas pressure and/or MgO surface characteristics at high ambient temperatures. This paper deals with the effect of working gas pressure on the misfiring of ac PDP at high ambient temperature. From this study, we found that the main cause of the misfiring at high ambient temperature is the increase in discharge firing voltage induced by increased working gas pressure

• Journal of the HCI Society of Korea
• /
• v.2 no.2
• /
• pp.27-34
• /
• 2007

In ubiquitous computing, there is increasing demand for ubiquitous displays that react to a user's actions. We propose a method of navigating pictures on an ambient display using implicit interactions. The ambient display can identify the user and measure how far away they are using an RFID reader and ultrasonic sensors. When the user is a long way from the display, it acts as a digital picture and does not attract attention. When the user comes within an appropriate range for interaction, the display shows pictures that are related to the user and provides quasi-3D navigation using the TIP(tour into the picture) method. In addition, menus can be manipulated directly on a touch-screen or remotely using an air mouse. In an emergency, LEDs around the display flash to alert the user.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.787-790
• /
• 2009

High contrast red, green and blue organic light-emitting diodes were fabricated using inorganic metal multi layer composed of thin Al, KCl and thick Al and then were compared to optical and electrical characteristics with the attached polarizer and conventional OLEDs. Ambient light reflection of OLED using inorganic metal layer, polarizer and conventional metal layer were 29.2, 31.1 and 82.5% respectively. Optical characteristics of OLEDs using inorganic metal layer were max luminescence of 13040 cd/m2 and luminous efficiency of 2.12 cd/A at 8V whereas OLEDs using polarizer has 8456 cd/m2 and 1.43 cd/A at 8V each. OLEDs including inorganic metal multi layers show significant technical advantages in achieving high performance of OLED display with improved contrast ratio of 251:1, specifically in Red OLED.

• Proceedings of the Korea Contents Association Conference
• /
• 2009.05a
• /
• pp.30-34
• /
• 2009

Recently, systems providing the interaction different according to an interval between a user and the display were developed in order to construct the ambient or the ubiquitous computing environment. Therefore, we propose a new type of spatial interaction system; our main goal is to provide the interactive domain in the large-scale ambient display environment. So, we divide into two zones of interaction dependent on the distance from the interaction surface interactive zone and ambient zone. In interactive zone, the users can approach the interaction surface and interact with natural hand-touch. When the users are outside the range of the interactive zone, the display shows only general information. Therefore, this system offers the various interactions and information to users in the ubiquitous ambient environment.

• Journal of the Ergonomics Society of Korea
• /
• v.21 no.1
• /
• pp.95-112
• /
• 2002

Two experiments were carried out to compare the suitability in visual tasks between cathode-ray tube (CRT) and thin film transistor-liquid crystal display (TFT-LCD). In the first experiment, the subjects were requested to detect pre-assigned target words or icons among distracters presented under time-invariant (static) image mode. The subjects' visual performance and fatigue were assessed while carrying out search tasks with dim and bright ambient light conditions. Significant interaction effects were found among displays, task types, and ambient light conditions. Due to visual fatigue, the subjects' accommodative power decreased in the end of task and the degradation was more significant for the CRT users and under bright ambient light. IN the second experiment, the subjects performed information processing task with time-varying road signs at a driving simulator to assess interaction effects between display types and changing speed of dynamic image. The perception time using TFT-TCD was shorter under slow image change while that of CRT was shorter rapid image change. Findings from this study suggest that, to improve visual task performance, users should carefully select their visual display type depending on the task to be performed.

• Journal of the Semiconductor & Display Technology
• /
• v.7 no.3
• /
• pp.51-54
• /
• 2008

In this study, we investigated variations in undoped ZnO thin film properties with working pressure, $O_2$/Ar ratio, and annealing ambient. Higher vacuum pressure during deposition was observed to bring about slower growth rate resulting in samples with better crystallinity as well as hole generation efficiency through formation of shallower oxygen interstitial. Given that $O_2$/Ar ratio is greater than unity, O provided from the ambient to ZnO during annealing was found to preferably situate at interstitial sites. When He was used for the second annealing, significant changes were not observed. On the other hand, O ambient caused increased density of oxygen interstitial, thereby making the film more intrinsic-like high resistivity ZnO.