• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.4
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• pp.54-61
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• 2013

UV-IR camera is being used for predictive maintenance of high voltage equipment together with measurement of temperature on localized heat and corona discharge. This paper was suggested the judgement method that is the discharge count, UV image pattern and discharge matching rate to apply the UV-IR camera on power facility. The discharge count method is counted by UV image pixel value. the UV image pattern method is determined by the UV image shape using neural network algorithm method, separated by Sunflower, Jellyfish, Ameba. The UV discharge matching is compare the breakdown the UV image size and measuring UV image size according to distance.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.91-95
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• 2006

High-density image sensors rave microlens array to improve photosensitivity. It is conventionally fabricated by reflow process. The reflow process has some weak points. UV imprinting process can be proposed as an alternative process to integrate microlens array on photodiodes. In this study, the UV imprionting process to integrate microlens array on image sensor was developed using UV transparent flexible mold and simulated image sensor substrate. The UV transparent flexible mold was fabricated by replicating master pattern using siliconacrylate photopolymer. The releasing property and shape accuacy of siliconacrylate mold was analysed. After UV imprinting process, replication quality and align accuracy was analysed.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.17-21
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• 2005

High-density image sensors have microlens array to improve photosensitivity. It is conventionally fabricated by reflow process. The reflow process has some weak points. UV imprinting process can be proposed as an alternative process to integrate microlens array on photodiodes. In this study, the UV imprionting process to integrate microlens array on image sensor was developed using W transparent flexible mold and simulated image sensor substrate. The UV transparent flexible mold was fabricated by replicating master pattern using siliconacrylate photopolymer. The releasing property and shape accuacy of siliconacrylate mold was analysed. After UV imprinting process, replication quality and align accuracy was analysed.

• Journal of Sensor Science and Technology
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• v.28 no.3
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• pp.152-156
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• 2019

An ultraviolet (UV) image sensor is an extremely important optoelectronic device used in scientific and medical applications because it can detect images that cannot be obtained using visible or infrared image sensors. Because photodetectors and transistors are based on different materials, conventional UV imaging devices, which have a hybrid-type structure, require additional complex processes such as a backside etching of a GaN epi-wafer and a wafer-to-wafer bonding for the fabrication of the image sensors. In this study, we developed a monolithic GaN UV passive pixel sensor (PPS) by integrating a GaN-based Schottky-barrier type transistor and a GaN UV photodetector on a wafer. Both individual devices show good electrical and photoresponse characteristics, and the fabricated UV PPS was successfully operated under UV irradiation conditions with a high on/off extinction ratio of as high as $10^3$. This integration technique of a single pixel sensor will be a breakthrough for the development of GaN-based optoelectronic integrated circuits.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.859-862
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• 2008

We have realized static image on organic light emitting diodes (OLEDs) using photoluminescence degradation. Ultraviolet (UV) was irradiated to the glass side of device. UV power was 350 Wand the wavelength was 365 nm. The UV irradiation gives rise to the degradation of photoluminescence. Due to the degradation, the current density-voltage curve was shifted to the higher voltage side and the luminescence was also degraded by the current and photoluminescence drop. The negative imaged films were prepared to control the transmittance of UV. The UV light was passed through the film. By this method, the film image was transferred to the device with reversed image and the static image was realized on the OLED.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.100-103
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• 2007

A microlens array has been required to improve light conversion efficiency in image sensors. A microlens array can be usually fabricated by photoresist reflow, hot-embossing, micro injection molding, and UV-imprinting. Among these processes, a UV-imprinting, which is operated at room temperature with relatively low applied pressure, can be a desirable process to integrate microlens array on image sensors, because this process provides the components with low thermal expansion, enhanced stability, and low birefringence, furthermore, it is more suitable for mass production of high quality microlens array. In this study, to analyze the optical properties of the wafer scale microlens array integrated image sensor, another wafer scale simulated image sensor chip array was designed and fabricated. An aspherical square microlens was designed and integrated on a simulated image sensor chip array using a UV-imprinting process. Finally, the optical performances were measured and analyzed.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.3
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• pp.365-371
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• 2011

Most recently issued paper money includes security patterns that can be only identified by ultra violet (UV) illuminations. We propose an automatic extraction method of UV patterns for paper money inspection systems. The image acquired by camera and UV illumination is transformed to input data through preprocessing. And then, the Gaussian mixture model (GMM) and split-and-merge expectation maximization (SMEM) algorithm are applied to segment the image represented by input data. In order to extract the UV pattern from the segmented image, we develop a criterion using the area of covariance vector and the weight value. The experimental results on various paper money are presented to verify the usefulness of the proposed method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.69-74
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• 2011

In this paper, the UV corona camera was developed using the solar blind and Multi Channel Plate(MCP) technology for the target localization of UV image. UV camera developed a $6.4[^{\circ}]{\times}4.8[^{\circ}]$ of the field of view as a conventional camera to diagnose a wide range of slightly enlarged, and power equipment to measure the distance between the camera and the distance meter has been attached. UV camera to measure the discharge count and the UV image was developed, compared with a commercial camera, there was no significant difference. In salt spray environments breakdown voltage was lower than the normal state, thereby discharging the image was rapidly growing phenomenon.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1590-1591
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• 2011

In this paper, the UV corona camera was developed using the solar blind and Multi Channel Plate(MCP) technology for the target localization of UV camera. UV camera developed a $6.4^{\circ}{\times}4.8^{\circ}$ of the field of view as a conventional camera to diagnose a wide range of slightly enlarged, and power equipment to measure the distance between the camera and the distance meter has been attached. The UV camera was developed and measured using a UV image, as applied voltage increased ultraviolet images of the phenomenon could be obtained. And we investigated properties of UV corona image on insulator in salt water environments. From the results, the breakdown voltage was decreased and UV images were taken at low voltages and the UV image is rapidly increased with increasing High voltage.

• Elastomers and Composites
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• v.51 no.1
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• pp.1-9
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• 2016

Characterization of the UV oxidation for raw natural rubber (NR) was investigated in controlled conditions through image and FT-IR analysis. The UV oxidation was performed on a thin film of natural rubber coated on a KBr window at 254 nm and room temperature to exclude the thermal oxidation. Before or after exposure to UV light, image of the NR thin film was observed at a right or tilted angle. FT-IR absorption spectra were measured in transmission mode with the UV irradiation time. The UV oxidation of NR was examined by the changes of absorption peaks at 3425, 1717, 1084, 1477, 1377, and $833cm^{-1}$ which were assigned to hydroxyl group (-OH), carbonyl group (-C=O), carbon-oxygen bond (-C-O), methylene group $(-CH_2-)$, methyl group $(-CH_3)$, and cis-methine group $(cis-CCH_3=CH-)$, respectively. During the initial exposure period, the results indicated that the appearance of carbonyl group was directly related to the reduction of cis-methine group containing carbon-carbon double bond (-C=C-). Most of aldehydes or ketones from carbon-carbon double bonds were formed very fast by chain scission. A lot of long wide cracks with one orientation at regular intervals which resulted in consecutive chain scission were observed by image analysis. During all exposure periods, on the other hand, it was considered that the continuous increment of hydroxyl and carbonyl group was closely related to the decrement of methylene and methyl group in the allylic position. Therefore, two possible mechanisms for the UV oxidation of NR were suggested.