• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.186-193
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• 2009

In this paper, we adopted E-MOLD patent technology in order to fabricate Prismless LGP(Light Guide Panel) fur cellular phone and estimate the transcription of injection-molded parts. Then, we manufactured the Ni stamper fur Prismless LGP using MEMS process. And the stamper was installed in the movable heated core which is the key part of a patented mold. Using this mold, we manufactured injection-molded plastic LGP parts with different mold temperatures so that we investigate effect of the temperature on the transcription of the parts. The CAE analysis was also conducted in order to compare with the experimental results. The transcription of LGP parts with various mold temperature displayed $100^{\circ}C$(25.0nm), $140^{\circ}C$(48.4nm), $180^{\circ}C$(52.1nm) and when compared with stamper(521Inm), transcription was superior at $180^{\circ}C$. According to the CAE results, moldability was improved as mold temperature ($50^{\circ}C{\sim}180^{\circ}C$) increased, but when filling time($1{\sim}2sec$) increases, it decreased at $160^{\circ}C$. And transcription and moldability were improved markedly at glass transition temperature($140^{\circ}C$).

• Journal of the Microelectronics and Packaging Society
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• v.14 no.2 s.43
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• pp.59-63
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• 2007

This paper presented a low-cost thick film gas sensor module, which was based on simple PCB (Printed Circuit Board) process. The proposed sensor module included a $NO_2/H_2$ gas sensor, a relative humidity sensor, and a heating element. The $NO_2/H_2$ gas and relative humidity sensors were realized by screen-printing $SnO_2,\;BaTiO_3$ nano-powders on IDTS (Interdigital Transducer) of a PCB substrate, respectively. At first 1% $H_2$ gas flowed into the sensor chamber. After 4 min, air filled the chamber while $H_2$ gas flow stopped. This experiment was performed repeatedly. The Identical procedure was used for the $NO_2$ detection. The result for sensing $H_2$ gas showed the increase of voltage from 0.8V to 3.5V due to the conductance increase and its reaction response time by hydrogen flow was 65 sec. $NO_2$ sensing results showed 2.7 V voltage drop due to the conductance decrease and its response time was 3 sec through a voltage monitoring.

• Korean Journal of Optics and Photonics
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• v.28 no.2
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• pp.59-67
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• 2017

This paper proposes an asymmetric split-loop resonator with an outer square loop (ASLR-OSL), which can actively control terahertz wave transmission properties while maintaining a high-Q-factor of the asymmetric split-loop resonator (ASLR). An added outer square loop is designed to play the roles of both a metamaterial and a micro-heater, which can control the temperature through a directly applied bias voltage. A vanadium dioxide ($VO_2$) thin film, which exhibits an insulator-metal phase transition with temperature change, is used to control the transmission properties. The proposed ASLR-OSL shows transmission properties similar to those of the ASLR, and they can be successfully controlled by directly applying bias voltage to the outer square loop. Based on these results, an electrically controllable terahertz high-Q metamaterial could be achieved simply by adding a square loop to the outside of a well-known high-Q metamaterial.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.1
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• pp.90-94
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• 2023

Carbon fiber(CF) with excellent thermal conductivity and electrical conductivity is attracting attention as an alternative material because metal heating elements have problems such as high heat loss and fire risk. However, since CF is oxidized and disconnected at about 200℃ or higher, the application of heating elements is limited, and CF heating elements in the form of vacuum tubes are currently used in some commercial heaters. In this work, polyimide(PI) with high heat resistance was coated on the surface of carbon fiber by electrophoretic deposition to prevent oxidation of CF in the atmosphere without using a vacuum tube, and the coating thickness and heat resistance were investigated according to the applied voltage. The heater made by connecting the PI-coated CF heating elements in series showed stable heating characteristics up to 292℃, which was similar to the heating temperature result of the heat transfer simulation. The PI layer coated by the electrophoretic deposition method is effective in preventing oxidation of CF at 200℃ or higher and is expected to be applicable to various heating components such as secondary batteries, aerospace, and electric vehicles that require heat stability.