• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.2
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• pp.1-9
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• 2006

As consumers in optics, electronics, aerospace and electronics industry grow, the demand for ultra-precision aspheric surface lens increases higher. To enhance the precision and productivity of ultra precision aspheric surface micro lens, the development of ultra-precision grinding system and process for the aspheric surface micro lens are described. In the work reported in this paper, an ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the ground surface roughness and profile accuracy. This paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. The optimization of grinding conditions on ground surface roughness and profiles accuracy is investigated using the design of experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.508-511
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• 2002

With increasing the needs for micro and precision parts, micro machining technology using micro tools has been studied to fabricate a small part with high density such as electronics, optics, communications, and medicine industry more than before. Though these micro tools have developed rapidly, it is difficult to apply them to micro fabrication technologies, because of the inherent manufacturing. In this study, micro tools(wc) to produce micro structures and parts were manufactured by cylindrical grinding machine employing ELID(Electrolytic In-process Dressing) technique and good dimensional accuracy was achieved. Furthermore we researched the characteristics of machining on the micro drilling using micro drills and manufactured micro tools. Finally it is confirmed that manufactured micro tools can be used for micro machining.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.91-94
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• 2022

Top emission organic light-emitting diode is commonly used because of high efficiency and good color purity than bottom - emission organic light-emitting device. Unlike BEOLED, TEOLED contain semi-transparent metal cathode. Because of semi-transparent cathode, micro cavity effect occurs in TEOLED. We optimized this effect by changing the thickness of hole injection layer. Device consists of is indium-tin-oxide / N,N'-Di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl-4,4'-diamine (x nm) / tris-(8-hydroxyquinoline) aluminum (50nm) / LiF(0.5nm) / Mg:Ag (1:9), and we changed NPB thickness which is used as HTL in our device in order to study how micro cavity effects are changed by optical path. As the results, NPB thickness at 35nm showed the current efficiency of 8.55Cd/A.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.23-27
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• 2019

In this paper, we propose a micro vibro tomography(MVT) method, that can be used to visualize two-dimensional cross-sectional images and micro-vibration tomographic images in real time in a non-contact and non-destructive manner. The proposed method is based on the optical coherence tomography(OCT) technique, with an additionally customized image processing algorithm. The proposed method can detect the micro-motions or vibrations in sample structures by measuring the phase shift variations in the sample structures. In this study, we show the potential capabilities of the proposed MVT system for measuring the micro-vibrations generated when sound waves in a frequency range of 2~5 kHz are applied to an $80-{\mu}m$ thick latex phantom, which mimics the changes in physical structure of the human tympanic membrane while hearing. Additionally, three-dimensional volumetric images of the MVT method were recorded to observe the surface morphological changes in the surface of the phantom sample which mimics the human tympanic membrane while hearing.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.183-190
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• 2013

In this paper, we propose an improved anisotropic diffusion model for micro-crack detection in heterogeneously textured surface of polycrystalline solar wafers. Due to the nature of the image sensor, the gray-level of the diagonal micro-crack is non-uniform. Thus, the conventional algorithms can't fully detect diagonal micro-cracks when the number of iteration is not enough. However, the increasing of the iteration number leads to increase computation time and detects micro-crack thicker than the original micro-crack. In order to overcome this drawback, we use the gradient of north, south, east, and west directions as well as extended directions. To calculate the diffusion coefficients, we compare the gradients of conventional directions and extended directions and apply the larger gradient values to the coefficient function. This is because the proposed method reflects the information of diagonal micro-crack. Comparing to Tsai et al.'s and Ko and Rheem's, the proposed algorithm shows superior efficiency in detecting the diagonal micro-cracks with less iterations in the images of polycrystalline solar wafers. In addition, it also shows that the thickness of segmented micro-crack is similar to the orignal micro-crack.

• Journal of Korean Electronics
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• v.7 no.11
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• pp.99-99
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• 1987

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.535-536
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• 2008

By reducing size of operation code, an improved MCU(micro controller unit) is implemented in this paper. The proposed MCU is developed for 32Bit Embedded System. The MCU has a general 32Bit MCU operations. The MCU supports to an ICE device.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.316-316
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• 2004

• ETRI Journal
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• v.30 no.3
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• pp.483-485
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• 2008

A micro-sensor network is comprised of a large number of small sensors with limited memory capacity. Current key-establishment schemes for symmetric encryption require too much memory for micro-sensor networks on a large scale. In this paper, we propose a memory-efficient hypercube key establishment scheme that only requires logarithmic memory overhead.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.589-592
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• 2004

The CORDIC algorithm can be implemented very simple H/W, but needs a lot of latency to compute trigonometric function. The RA(Redundant Arithmetic) resolves this problem, but also has difficulty to determine the directions of micro-rotations. The pre-computed direction of micro-rotation algorithm relieves the RA of this matter. In this paper, we proposed the modified the pre-computed algorithm adopted with a table-lookup. Instead of reducing H/W complexity, its performance and calculation errors are improved.