• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.121-127
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• 2022

Micro-LED is a light-emitting diode smaller than 100 ㎛ in size. It attracts much attention due to its superior performance, such as resolution, brightness, etc., and is considered for various applications like flexible display and VR/AR. Micro-LED display requires a mass transfer process to move micro-LED chips from a LED wafer to a target substrate. In this study, we proposed a vacuum chuck method as a mass transfer technique. The vacuum chuck was fabricated with MEMS technology and PDMS micro-mold process. The spin-coating approach using a dam structure successfully controlled the PDMS mold's thickness. The vacuum test using solder balls instead of micro-LED confirmed the vacuum chuck method as a mass transfer technique.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.241-244
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• 2004

Microlens patterned micro-mold fabrication method for Light Guiding Plate(LGP), kernel part of LCD-BLU(Back Light Unit), was presented. Instead of erosion dot pattern for LCP optical design, microlens pattern, fabricated by LIGA-reflow process, was applied. Optical pattern design method was also developed not only for negative pattern LGP, but also positive pattern LGP. In order to achieve flow balance during the micro-injection molding process and dimensional accuracy, two LGP pattern was made in one micro-mold.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.285-290
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• 2005

Micro On-Off valves are currently recognized as the core technology in the fields of the micro fluid chip fur medical applications and production lines of semi-conduct chip. Micro valves that operate by compressed air need the high-speed responsibility, repeatability, the absorbability and the uniform pressure by the poppet. In this study, Micro On-Off valves that posses the high-speed responsibility and the high rate of flow have designed and analyzed through the law of equivalent magnetic circuit and Finite Element Method (FEM) respectively. In case of poppet, Flow field characteristic was analyzed by the variation of poppet and it was able to display flow field by changing the location of the poppet. Also, we verified possibility of the design through the static and dynamic pressure and the 3D distribution curve of the force by working the front poppet.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.105-110
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• 2006

The highly integrated nature of polymer based organic light emitting diode (POLED) microdisplay technology, coupled with low voltage and low power electroluminescent light generation, combine to offer a very promising technology for use in portable and personal electronics products. We briefly describe the technology before discussing how to engineer the color gamut using whiteemitting polymer materials, microcavity device structure and color filter absorbance.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.354-359
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• 2006

Recently, the interest in lithography without photo exposure has been increased compare to the conventional photolithography in nano meter and micrometer size patterning area. We studied a self aligned dipping of Ag solution through micro contact printing (${\mu}-CP$) with octadecyltrichlorosilane (OTS) treated polydimethylsiloxane (PDMS) soft mold. The OTS monolayer on the patterned PDMS was formed by dipping it into OTS solution. We transferred the OTS monolayer from PDMS mold to the glass. The OTS monolayer changed the surface energy from hydrophilic surface to hydrophobic surface, And then we made self aligned Ag solution patterns just after dipping the substrate, using adhesion difference of Ag solution between OTS treated hydrophobic area and non-OTS treated hydrophilic area. We finally get the Ag patterns through only dip-coating after the ${\mu}-CP$ process. And we observed surface energies on the glass substrate through the contact angle measurements as time goes on.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.10a
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• pp.33-48
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.100-101
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• 2004

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.23-23
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• 1998

High resolution field emission dispplay(FED) devices of 5 inch diagonal in size are fully developped for the applications of near-future flat ppanel dispplays. Under the unique gate-switching drive scheme electron trajectory pprofiles are simulated and tested by considering leakage effects of each ppixel. Uniquely-pprinted sppacer with high asppect ratio are fabricated on real ITO glass for high vacuum ppackaging. In addition new gas aging scheme of stabilizing field emitting array are extensively investigated during the sealing and exhausting pprocess in order to pprevent oxidation effects on the micro tipp. Finally fulll color images of 64 gray scale will be demonstrated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.371-376
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• 1997

A 100*100.mu.m$^{2}$ aluminum micro mirror is designed and fabricated using a thick photoresist as a sacrificial layer andas a mold for nickel electroplating. The micro mirror is composed of aluminum mirror plate, two nickel support posts, two aluminum hinges, two address eletrodes, and two landing electrodes. The aluminum mirror plate,which is supported by two nickel support posts, is overhung about 10.mu.m from the silicon substrate. THe aluminum mirror plate is actuated like a seesaw by electrostatic force generated by electic potential difference applied between the mirror plate and the address electrode. This paper presents some methods to measure the optical and the dynamic characteristics of the fabricated micro mirror.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.149-150
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• 2000

Lead-doped calcium sulfide(CaS:Pb) thin film electroluminescent devices were deposited using atomic layer deposition(ALD). CaS:Pb is a very promising blue phosphor showing very high luminance and the color coordinate close to the blue of cathode ray tube. The luminance, $L_{25}$, of CaS:Pb(1.6 mol.%) EL device was higher than 80 $cd/cm^2$ at a driving frequency of 60Hz. The color coordinates of blue EL emission of CaS:Pb deposited by ALD are consistent with the Pb concentration ranging from approximately 0.5 to 3 mol.%.