• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1079-1081
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• 2006

Optical and electrical properties of various transparent conducting oxides (ITO, AZO, ITO/Ag/ITO, AZO/Ag/AZO) were investigated for anode of OLED display. ITO/Ag/ITO multi-layer anode has much better electrical and optical characteristics than other films, and OLED on that anode showed lower threshold voltage and better luminescence.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1028-1029
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• 2006

We have developed a self-aligned single isolation structure (SIS) and an asymmetric single isolation structure with an image reversal photoresist to increase the aperture ratio in a passive matrix organic light emitting display (PMOLED). Compared to the conventional structure, the fabrication process is reduced by about 17% and the aperture ratio is enlarged over 4%.

• Information Display
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• v.4 no.2
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• pp.7-10
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• 2003

현대는 디스플레이 산업과 같은 표시 소자 산업이 관심의 대상이 되고 있는 시대이다. 이러한 디스플레이 산업의 분야에는 CRT, LCD, PDP가 현재의 산업을 주도해왔고, OLED가 차세대 디스플레이로 주목을 받고 있다. 그래서 에이엔에스는 새로운 SMOLED(Small Molecule Organic Light Emitting Diode)를 제작할 수 있는 장비 및 공정기술을 개발하였다. 현재의 SMOLED 제작공정 및 장비와, 대면적 기판을 사용할 수 있고, 물질의 사용효율 및 공정시간을 단축시킬 수 있는 새로운 에이엔에스 증착장비의 장비 및 공정에서의 장단점을 비교하고 디바이스에서의 기본적인 특성을 비교하여 보겠다.

• Journal of Information Display
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• v.12 no.1
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• pp.57-59
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• 2011

Drastic performance increase and accelerated progress in organic light-emitting diodes from solutions are shown using solution-processable small molecules based on the core structures of vacuum-evaporable materials. Systematic modification of small-molecule materials toward better processability from solutions at identical electro-optical properties is shown. This is demonstrated to lead to a significant improvement in the device performance.

• Ceramist
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• v.21 no.1
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• pp.4-11
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• 2018

Display is an essence in human-machine communication interface. As mobile environment such as internet of things (IOT) and Artificial Intelligence (AI) progress, importance of display increases. Here we review research trend in flexible organic light emitting displays (OLEDs). This review article covers all the components consisting of flexible OELDs and shows direction of the recent research. This paper would be helpful for readers and researchers working in this field and provide perspective for future displays.

• Journal of Information Display
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• v.10 no.3
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• pp.111-116
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• 2009

In this paper, a plasma-assisted patterning method for the organic layers of organic light-emitting diodes (OLEDs) and its effect on the OLED performances are reported. Oxygen plasma was used to etch the organic layers, using the top electrode consisting of lithium fluoride and aluminum as an etching mask. Although the current flow at low voltages increased for the etched OLEDs, there was no significant degradation of the OLED efficiency and lifetime in comparison with the conventional OLEDs. Therefore, this method can be used to reduce the ohmic voltage drop along the common top electrodes by connecting the top electrode with highly conductive bus lines after the common organic layers on the bus lines are etched by plasma. To further analyze the current increase at low voltages, the plasma patterning effect on the OLED performance was investigated by changing the device sizes, especially in one direction, and by changing the etching depth in the vertical direction of the device. It was found that the current flow increase at low voltages was not proportional to the device sizes, indicating that the current flow increase does not come from the leakage current along the etched sides. In the etching depth experiment, the current flow at low voltages did not increase when the etching process was stopped in the middle of the hole transport layer. This means that the current flow increase at low voltages is closely related to the modification of the hole injection layer, and thus, to the modification of the interface between the hole injection layer and the bottom electrode.

• Vacuum Magazine
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• v.4 no.2
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• pp.24-28
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• 2017

Organic light-emitting diodes (OLEDs) have already been commercialized for the mobile-phone display, TV, and lighting panels. Even though the OLED display for the mobile phones is now considered as the main stream display for the application, the OLED TV and lighting panels are having difficulty in their market due to their high prices despite the better performance to the competitors. In recent years, roll-to-roll production of the OLED has begun to be examined, and this method is opening a way to solve the high price problem. In this article, we introduce several important processes for roll-to-roll production of OLED and explain the development status to date.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.3
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• pp.10-17
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• 2024

This paper discusses Chip On Film (COF) technology, one of the key technologies in flexible packaging to enable miniaturization and flexibility of electronic devices. COF attaches Display Driver IC (DDI) directly to a flexible polyimide substrate, enabling lightweight and reduced thickness for high-resolution displays. COF technology is primarily used in high-performance display panels, such as organic light emitting diode (OLED) displays, and plays a key role in portable electronic devices, such as smartphones and wearable devices. This study analyzes the key components of COF and advances in bonding technology. In particular, the introduction of modern bonding techniques, such as thermo-compression bonding and thermo-sonic bonding, has led to significant improvements in bonding reliability and electrical performance. These bonding techniques enhance the mechanical stability of COF packages while maintaining high electrical connectivity in fine-pitch structures. This paper will discuss the future development of COF bonding technology and its challenges and explore its potential as a next-generation display and advanced packaging technology.

• Journal of the Semiconductor & Display Technology
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• v.12 no.2
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• pp.13-17
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• 2013

In lighting system where several large-area organic light-emitting diode (OLED) lighting panels are involved, panel aging may appear differently from each other, resulting in a falling-off in lighting quality. To achieve uniform light output across large-area OLED lighting panels, we have employed an optical feedback circuit. Light output from each OLED panel is monitored by the optical feedback circuit that consists of a photodiode, I-V converter, 10-bit analogdigital converter (ADC), and comparator. A photodiode generates current by detecting OLED light from one side of the glass substrate (i.e., edge emission). Namely, the target luminance from the emission area (bottom emission) of OLED panels is monitored by current generated from the photodiode mounted on a glass edge. To this end, we need to establish a mapping table between the ADC value and the luminance of bottom emission. The reference ADC value corresponds to the target luminance of OLED panels. If the ADC value is lower or higher than the reference one (i.e., when the luminance of OLED panel is lower or higher than its target luminance), a micro controller unit (MCU) adjusts the pulse width modulation (PWM) used for the control of the power supplied to OLED panels in such a way that the ADC value obtained from optical feedback is the same as the reference one. As such, the target luminance of each individual OLED panel is unchanged. With the optical feedback circuit included in the lighting system, we have observed only 2% difference in relative intensity of neighboring OLED panels.

• Journal of the Semiconductor & Display Technology
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• v.21 no.2
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• pp.25-31
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• 2022

By an aid of needle coating, we have fabricated a spherical microlens array using poly(methyl methacrylate) for potential applications in light extraction of organic light-emitting diodes. With an attempt to achieve high-density and high-aspect-ratio microlens arrays, we have investigated the coating behaviors by varying the material parameters such as the solute concentration and wettability of the poly(methyl methacrylate) solution and process parameters such as the dwell time of needle near the substrate, retract distance of needle from the substrate, and coating gap between the needle and substrate. Under the optimized coating conditions, it is demonstrated that high-aspect-ratio microlens arrays can be obtained using a coating solution with high solute concentration and a small amount of a hydrophobic solvent. It is found that the diameter and height of microlens array are decreased with increasing poly(methyl methacrylate) concentration, yet the overall aspect ratio is rather enhanced. By the addition of 5 wt% hexylamine in 35 wt% poly(methyl methacrylate) solution, we have achieved a spherical microlens with the height of 7.7 ㎛ and the width of 94.24 ㎛ (the aspect ratio of 0.082). To estimate the capability of light extraction by the microlens array, we have performed ray tracing simulations and demonstrated that the light extraction efficiency of organic light-emitting diode is expected to be enhanced up to 24%.