• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.15.2-15.2
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• 2009

Manufacturing of printed electronics using printing technology has begun to get into the hot issue in many ways due to the low cost effectiveness to existing semi-conductor process. This technology with both low cost and high productivity, can be applied in the production of organic thin film transistor (OTFT), solar cell, radio frequency identification (RFID) tag, printed battery, E-paper, touch screen panel, black matrix for liquid crystal display (LCD), flexible display, and so forth. The emerging technology to manufacture the products in mass production is roll-to-roll printing technology which is a manufacturing method by printings of multi-layered patterns composed of semi-conductive, dielectric and conductive layers. In contrary to the conventional printing machines in which printing precision is about $50~100{\mu}m$, the printing machines for printed electronics should have a precision under $30{\mu}m$. In general, in order to implement printed electronics, narrow width and gap printing, register of multi-layer printing by several printing units, and printing accuracy of under $30{\mu}m$ are all required. We developed the roll-to-roll printing equipment used for printed electronics, which is composed of un-winder, re-winder, tension measurement system, feeding units, dancer systems, guide unit, printing unit, vision system, dryer units, and various auxiliary devices. The equipment is designed based on cantilever type in which all rollers except printing ones have cantilever types, which could give more accurate machine precision as well as convenience for changing rollers and observing the process.

• Journal of Information Display
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• v.4 no.1
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• pp.17-23
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• 2003

A thermoset type anisotropic conductive adhesive film (ACAF) comprising epoxy resin and natural butyl rubber (NBR) as the binder, micro-encapsulated imidazole as the curing agent, and Ni/Au coated polymer bead as a conductive particle has been studied. These films have been prepared to respond to requirements such as improved contact resistance, current status less of than 60 ${\mu}m$ and reliability. These films can also be used for connection between the ITO glass for LCD panel and the flexible circuit board. The curing conditions for the connection were 40, 20 and 15 seconds at 150, 170 and 190 $^{\circ}C$, respectively. The initial contact resistance and adhesion strength were 0.5 ${\Omega}/square$ and 0.4 kg/cm under the condition of 30 kgf/$^{cm}^2}$, respectively. After completing one thousand thermal shock cycling tests between -15 $^{\circ}C$ and 100 $^{\circ}C$, the contact resistance was maintained below 0.7 ${\Omega}/square$. Durability against high temperature (80$^{\circ}C$) and high humidity (85 % RH) was also tested to confirm long-term stability (1000 hrs) of the conduction.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.83-89
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• 2012

A simple array of metal-insulator-metal capacitive elements was proposed for a potential application in humidity sensing platforms. We fabricated meso-scale sensors with different sizes(large-size: $2.7{\times}2.7mm^2$ ; mid-size: $1.5{\times}1.5mm^2$ ; small-size: $0.7{\times}0.7mm^2$) and characterized the performance of each design. Polyimide films were utilized as a humidity-sensitive layer. Capacitance changes of the polyimide layer were measured with respect to water absorption. The device showed sensitivity in the full range of relative humidity (RH) with excellent linearity(correlation coefficient > 0.994). This array structure exhibits unique advantages including easy fabrication process, high batch productivity, and high structural compatibility with various substrate materials. It is anticipated that this device structure will be potentially useful in unique applications including mapping spatial humidity variations over a meso-scale area and implementing flexible humidity sensing element arrays.

• Physical Therapy Korea
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• v.28 no.2
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• pp.117-122
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• 2021

Background: Flat-back posture refers to a posture in which the pelvis is tilted backward, the lumbar spine is bent, the upper thoracic spine is increasingly bent, and the lower thoracic spine is straight. Given that most of the day is spent sitting, we need to develop exercise programs and devices that are suitable for people who spend less time exercising than sitting. Objects: This study investigated the effects of resistance footrest exercise on spine posture angles in visual display terminal (VDT) workers with flat back. Methods: We measured the upper lumbar angle (ULA) and lower lumbar angle (LLA) using a flexible ruler for the ULA and LLA. Then, after 1 week of resistance footrest exercise designed to strengthen the lumbar spine musculature, we measured these angles again. We measured each angle three times and then compared measurements from before and after exercise. Results: There were no significant differences in the ULA following the strengthening exercise, but significant differences were observed in LLA. Conclusion: The resistance footrest exercise strengthened the muscles affecting the pelvic and lumbar lordotic angles, and increases in the LLA were changed. This suggests that the role of the lower lumbar spine in the lumbar lordotic curve is greater than that of the upper lumbar spine. In addition, considering the contemporary tendency to lead fairly sedentary lives, these results indicate that exercising while seated can be effective.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.31-35
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• 2017

We have fabricated flexible and stretchable pressure sensors using silver nanowires (AgNWs) and analyzed their electric responses. AgNWs are spray coated directly onto uncured polydimethylsiloxane (PDMS) such that AgNWs penetrate into the uncured PDMS, enhancing the adhesion properties of AgNWs. However, the single-layered AgNW sensor exhibits unstable electric response and low pressure sensitivity. To tackle it, we have coated a conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) onto the AgNW layer. Such a hybrid bilayer sensor ensures a stable electric response because the over-coating layer of PEDOT:PSS effectively suppresses the protrusion of AgNWs from PDMS during release. To enhance the sensitivity further, we have also fabricated a stacked bilayer AgNW sensor. However, its electric response varies depending sensitively on the initial overlap pressure.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.509-516
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• 2022

Recently, ships have begun using the Asterix CAT 240 format as a method for transmitting radar image data to other devices. However, the Asterix format has a flexible structure that can be defined by the user, and a format structure defined as unsuitable for ship radar operation may undesirably increase navigational equipment network traffic or reduce stability. Therefore, to reduce the traffic of the navigation network and enhance the stability, a method of defining the optimized Asterix CAT 240 format with an appropriate setting value according to the performance of the radar scanner and display device was studied.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.711-717
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• 2010

In this paper, a new automatic punching system that generates pinholes expressing texts or images on a plastic plate is developed. The pin-holed plate is used as a new glamorous display board reflecting colourful lights from the light emitting diode (LED) installed on the edge side of the plate. The punching system has four actuators which work together to make multiple holes with accurate position and depth on the plastic plate. For even reflection of the lights from texts or images on the board and fast production of the pin-holed boards, we developed an accurate actuating structure of the system cooperating with a PID control algorithm. We also built a GUI-based integrated control system to help users easily design luminous texts or images on the plastic plate. Also, we conducted a performance test of the system to verify the punching speed and depth control of the pin holes on the plastic plate.

• The Journal of the Korea Contents Association
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• v.15 no.9
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• pp.37-46
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• 2015

Nowadays, given the popularity of wearable devices, The smartwatch is considered as the leading product category and taking the main share of wearable device market. So far smartwatch is only used as an accessorial device of smart phones due to its screen size. The objective of this study is to review literatures and find solutions to overcome the screen limitations. In the literature review, several methods are introduced including using other devices as output devices, other object as screens by projecting technologies, and enlarging screen size by flexible display. Based on that, possible solutions including seamless display and user-centered interaction methods were investigated. Future research directions were also introduced at the end of this study.

• Journal of the Semiconductor & Display Technology
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• v.8 no.4
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• pp.15-19
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• 2009

A high efficient organic red light emitting device with structure of DNTPD/TAPC/$Bebq_2$ :[$(pq)_2Ir(acac)$, SFC-411]/SFC-137 was fabricated on the plastic substrate, which can be applied in the fields of flexible display and illumination. In the device structure, N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolylamino)-phenyl]-biphenyl-4,4'-diamine[DNTPD] as a hole injection layer and 1,1-bis-(di-4-tolylaminophenyl) cyclohexane [TAPC] as a hole transport were used. Bis(10-hydroxybenzo[h]quinolinato) beryllium complex [$Bebq_2$] was used as a light emitting host material. The host material, $Bebq_2$ was doubly doped with volume ratio of 7% iridium(III)bis-(2-phenylquinoline)acetylacetonate[$(pq)_2$Ir(acac)] and 3% SFC-411[red phosphor dye coded by the proprietary company]. And then, SFC-137 was used as an electron transport layer. The luminous intensity and current efficiency of the fabricated device were $22,780\;cd/m^2$ at 9V and 17.3 cd/A under $10,000\;cd/m^2$, respectively. The maximum current efficiency of the device was 22.4cd/A under $580\;cd/m^2$.

• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.585-593
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• 2010

Recently, we designed an interactive virtual space for the multi-purpose hall in Songdo Future City, located in Incheon, Korea. The goal of the design is to make a virtual space that is flexible and can be adjusted thanks to its unfixed seats in order to accommodate different and unspecified audience sizes. Virtual images are interactively adjusted according to the distance, position and size of audiences, information about which is detected by 9 photo sensors. To increase the sense of immersion, intensity and reality, we utilized the technology of scent display that can create appropriate scents to match the images on the screen. The intensity and persistence of scents were determined by the size, distance and position of audiences. The virtual image contains background images and reactive images. The background images repeatedly project images of spring, summer, autumn and winter. The reactive images consist of small portraits or pictures or icons that define or characterize the season types, and these are added to the background image according to the distance, position and size of the audiences.