• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.886-888
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• 2009

We fabricated flexible electronic paper display(EPD) by using toner particles on plastic (PC) substrate. We observed the relationship between contrast ratio and changes of rib structures. One is a fabrication of ribs on bottom substrate. The display with ribs on bottom substrate had higher contrast ratio about 46% than display with ribs on top substrate. The other is a change of density of rib. The less density of ribs fabricated, the higher the contrast ratio become.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.13-13
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• 2009

We have investigated the fabrication and properties of bendable PZT film formed on plastic substrates for the application in flexible memory. These devices used the PZT active layer formed on $SiO_2/Si$ wafer by sol-gel method with optimized device layouts and Pt electrodes. After etching Pt/PZT/Pt layers, patterned by photolithography process. these layers were transferred on PET plastic substrate using elastomeric stamp. The level of performance that can be achieved approaches that of traditional PZT. devices on rigid bulk wafers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.7
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• pp.510-514
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• 2018

This study discusses and demonstrates the structural stability of highly ordered Pt patterns formed on a transparent and flexible substrate through the process of nanotransfer printing (nTP). Bending tests comprising approximately 1,000 cycles were conducted for observing Pt line patterns with a width of $1{\mu}m$ formed along the direction of the horizontal (x-axis) and vertical (y-axis) axes ($15mm{\times}15mm$); and adhesion tests were performed with an ultrasonicator for a period greater than ten minutes, to analyze the Pt crossbar patterns. The durability of both types of patterns was systematically analyzed by employing various microscopes. The results show that the Pt line and Pt crossbar patterns obtained through nTP are structurally stable and do not exhibit any cracks, breaks, or damages. These results corroborate that nTP is a promising nanotechnology that can be applied to flexible electronic devices. Furthermore, the multiple patterns obtained through nTP can improve the working performance of flexible devices by providing excellent structural stability.

• Journal of Welding and Joining
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• v.32 no.3
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• pp.34-42
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• 2014

Flexible devices have been developed from their rigid, heavy origins to become bendable, stretchable and portable. Such a paper displays, e-skin, textile electronics are emerging research areas and became a mainstream of overall industry. Thin film transistors, diodes and sensors built on plastic sheets, textile and other unconventional substrates have a potential applications in wearable displays, biomedical devices and electronic system. In this review, we describe current trends in technologies for flexible/wearable electronics.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.489.2-489.2
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• 2014

The planar type flexible piezoelectric energy harvesters (PEH) based on PbZr0.52Ti0.48O3 (PZT) thin films on the flexible substrates are demonstrated to convert mechanical energy to electrical energy. The planar type energy harvesters have been realized, which have an electrode pair on the PZT thin films. The PZT thin films were deposited on double side polished sapphire substrates using conventional RF-magnetron sputtering. The PZT thin films on the sapphire substrates were transferred by PDMS stamp with laser lift-off (LLO) process. KrF excimer laser (wavelength: 248nm) were used for the LLO process. The PDMS stamp was attached to the top of the PZT thin films and the excimer laser induced onto back side of the sapphire substrate to detach the thin films. The detached thin films on the PDMS stamp transferred to adhesive layer coated on the flexible polyimide substrate. Structural properties of the PZT thin films were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). To measure piezoelectric power generation characteristics, Au/Cr inter digital electrode (IDE) was formed on the PZT thin films using the e-beam evaporation. The ferroelectric and piezoelectric properties were measured by a ferroelectric test system (Precision Premier-II) and piezoelectric force microscopy (PFM), respectively. The output signals of the flexible PEHs were evaluated by electrometer (6517A, Keithley). In the result, the transferred PZT thin films showed the ferroelectric and piezoelectric characteristics without electrical degradation and the fabricated flexible PEHs generated an AC-type output power electrical energy during periodically bending and releasing motion. We expect that the flexible PEHs based on laser transferred PZT thin film is able to be applied on self-powered electronic devices in wireless sensor networks technologies. Also, it has a lot of potential for high performance flexible piezoelectric energy harvester.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.1
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• pp.7-15
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• 2024

In the trend of the multi-functionalization, miniaturization, and increased power output trends of flexible and stretchable electronic devices, the development of materials or structures with superior heat transfer characteristics has become a pressing issue. Traditional thermal interface materials (TIM) fail to meet the heat dissipation requirements of flexible and stretchable electronic devices, which must endure rapid bending, twisting, and stretching. To address this challenge, there is a demand for the development of TIM that simultaneously possesses high thermal conductivity and stretchability. This paper examines the research trends of liquid metal, carbon, and ceramic-based stretchable thermal interface materials and explores effective strategies for enhancing their thermal and mechanical properties.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.255-257
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• 2006

This paper proposed a platform which includes both Network processor and DSP for flexible IED. The Network processor is one of the Intel's IXP4XX Product Line family and the DSP is one of the TI's C6000 family. An embedded Linux is ported in Network processor so that a DSP program can be downloaded to Network processor through ethernet and then downloaded to DSP. Using this method, various algorithms according to IED can be applied to the Network processor board. Maximum ten ADCs can be connected because there is a CPLD between DSP and ADC. That is, the network processor board which can measure maximum 40 channels is implemented. In DSP program, thread and double buffering methods are used not to miss voltage samples. The Network processor board is verified using a method that eight channel voltage signals converted to digital are transmitted to server through both DSP and IXP425.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.42-42
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• 2008

Considerable attention has been focused on the applications of flexible liquid crystal (LC)-based displays because of their many potential advantages, such as portability, durability, light weight, thin packaging, flexibility, and low power consumption. To develop flexible LCDs that are capable of delivering high-quality moving images, like conventional glass-substrate LCDs, the LC device structure must have a stable alignment layer of LC molecules, concurrently support uniform cell gaps, and tightly bind two flexible substrates under external tension. However, stable LC molecular alignment has not been achieved because of the layerless LC alignment, and consequently high-quality images cannot be guaranteed. To solve these critical problems, we have proposed a PDMS pixel-wall based bonding method via the IB irradiation was developed for fasten the two substrates together strongly and maintain uniform cell gaps. The effect of the IB irradiation on PDMS with PI surface was also evaluated by side structure configuration and a result of x-ray photoelectron spectroscopic analysis of PDMS interlayer as a function of binder with substrates. large number of PDMS pixel-walls are tightly fastened to the surface of each flexible substrate and could maintain a constant cell gap between the LC molecules without using any other epoxy or polymer. To enhance the electro-optical performance of the LC device, we applied an alignment method that creates pretilt angle on the PI surface via ion beam irradiation. Using this approach, our flexible LCDs have a contrast ratio of 132:1 and a response time of about 15 ms, resulting in highly reliable electro-optical performance in the bent state, comparable to that of glass-substrate LCDs.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1730-1732
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• 2000

Powder Electroluminescent Device is the solid state device which has a low power consumption, large area emission with uniformity, easy manufacturing, simple structure, and flexible mechanically. In this paper, we made the information display with the powder electroluminescent device using back-light and designed the driving circuit.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1369-1375
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• 2016

A rapid progress of the next-generation non-volatile memory device has been made in recent years. Metal/insulator/Metal multi-layer structure resistive RAM(ReRAM) has attracted a great deal of attention because it has advantages of simple fabrication, low cost, low power consumption, and low operating voltage. This paper describes the working principle of the ReRAM device, a review of fabrication techniques, and characteristics of flexible ReRAM devices using graphene oxide as an insulating layer and ReRAM devices using multi-layered insulator. The switching characteristics of the above ReRAM devices have been compared. The oxidized graphene could be employed as an insulator of next generation ReRAM devices.