• Transactions of Materials Processing
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• v.12 no.5
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• pp.487-492
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• 2003

Tension variations with heat treatment in shadow mask for flat braun tubes are investigated in this study. In CRT, landing shift of the electron beam due to thermal deformation of the tension mask made the color purity of screen worse. In order to get the final results of thermal deformation, the tensile force within the mask and the welding processes between the rail and the extended mask have to be analysed sequentially. In this study, the effect of heat treatment is studied in terms of tension variations of shadow mask during its manufacturing process.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.12
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• pp.50-56
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• 2007

Femtosecond laser ablation of the Invar alloy and hole drilling for a shadow mask are studied. We used a regenerative amplified Ti-sapphire laser with a 1kHz repetition rate, 184fs pulse duration and 785nm wavelength. Femtosecond laser pulse was irradiated on the Invar alloy with air blowing at the condition of various laser peak power. An ablation characteristic of the Invar alloy was appeared non-linear at $125J/cm^2$ of energy fluence. For the application to a shadow mask, the hole drilling of the Invar alloy with the cross section of a trapezoidal shape was investigated. The ablated micro-holes were characterized using an atomic force microscopy(AFM). The optimal condition of hole pattern f3r a shadow mask was $4\;{\mu}m$ z-axis feed rate, 0.2mm/s circular velocity, $26.4{\mu}J$ laser peak power. With the optimal processing condition, the fine circular hole shape without burr and thermal damage was achieved. Using the femtoseocond laser system, it demonstrates excellent tool for the Invar alloy micro-hole drilling without heat effects and poor edge.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.251-256
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• 1993

In KACC'91 and '92 conference, we proposed a method of automatically detecting the shape of the faulty holes in a shadow mask by use of CCD ca.mera and image data processing technic. In this method, two adjoining test areas from one image data. of the shadow mask are taken and comparing the shape of holes in these two areas, we can detect the faults in the shadow mask. In this paper, a method is described by use of spatial filtering of effectively finding the faulty holes from the difference image data between the two tested image data. The main role of the filter is to remove sampling errors occurring at the edge of the holes. And the second role is not only to find the existence of faulty holes but also exactly express the shape of faulty holes. Computer simulations and actual experiments with shadow masks have shown that this method of fault detection is very effective for practical use.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.176-180
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• 1992

At the KACC'91 conference, we proposed a method of automatic detection of shape of the faulty holes of a shadow mask which is used in a cathode-ray tube of a color television. In this method, the image data are taken from two areas of the mask with CCD camera. Comparing the shape of holes in these two areas by use of a signal processing technique, we can find any fault in the shape of holes. This paper describes the effect of smoothing filters of effectively finding the faulty holes from the difference image data. A computer simulation and actual experiment with a shadow mask have shown that this method of fault detection is very effective for practical use.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.770-772
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• 2002

A new dry-processing method of organic gate dielectric film in field-effect transistors (FETs) was proposed. The method use vapor deposition polymerization (VDP) that is continuous and low temperature process. It has the advantages of shadow mask patterning and dry processing in flexible low-cost large area applications. Here, 80 nm-thick Al as a gate electrode was evaporated through shadow mask. Gate insulators used two different polyimides. The one material was 4,4'-oxydiphtahlic anhydride (ODPA) and 4,4'-oxydianiline (ODA). Another was 2,2-bis(3,4-dicarboxyphenyl) Hexafluoropropane Dianhydride (6FDA) and 4,4' -oxydianiline (ODA). These were co-deposited by high-vaccum thermal-evapora and cured at 150 $^{\circ}C$ for 1 hour, respectively. Pentacene as a semiconductor and 100 nm-thick Au as a source and drain electrode were evaporated through shadow mask.

• Journal of Powder Materials
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• v.10 no.4
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• pp.262-269
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• 2003

Nano-sized Ni-ferrite powder was fabricated by spray pyrolysis process using the waste solution resulting from shadow mask processing. The average particle size of the powder was below 100 nm. The effects of the concentration of raw material solution, the nozzle tip size and air pressure on the properties of powder were studied. As the concentration increased, the average particle size of the powder gradually increased and its specific surface area decreased, but size distribution was much wider and the fraction of the Ni-ferrite phase greatly increased as the concentration increasing. As the nozzle tip size increased from 1 mm to 2 mm, the average particle size of the powder decreased. In case of 3 mm nozzle tip size, the average particle size of the powder increased slightly. On the other hand, in case of 5 mm nozzle tip size, average particle size of the powder decreased. Size distribution of the powder was unhomogeneous, and the fraction of the Ni-ferrite phase decreased as the nozzle tip size increasing. As air pressure increased up to 1 kg/$cm^2$, the average particle size of the powder decreased slightly, on the other hand, the fraction of the Ni-ferrite phase was almost constant. In case of 3kg/$cm^2$ air pressure, average particle size of the powder and the fraction of the Ni-ferrite phase remarkably decreased, but size distribution was narrow.

• Transactions of Materials Processing
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• v.12 no.2
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• pp.123-127
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• 2003

The cold rolling conditions for the ultra thin steel for tension mask are very important because the residual stress that affects the flatness of strip is generate during the cold rolling. The residual stress in the sheet causes etching curls when it suffers perforation process. The residual stress through the thickness. To estimate the residual stress and deformation due to etching curl. FEM analysis is performed. Numerical simulation employ a ANSY5 5.6 and an elastic-plastic constitutive equation. The simulation results indicate the distribution of residual stress in the rolled sheet can be controlled by selecting the rolling conditions properly.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.261-266
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• 1993

This paper describes a 3-dimensional profile measurement method which was intended especially for sheet metal products such as shadow masks. The method is based upon machine vision in which the height variation of the surface is measured by software auto-forus image processing techniques. The method is found suitable for flexible surfaces with interrupt.

• Journal of Korea Technology Innovation Society
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• v.7 no.3
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• pp.641-656
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• 2004

L Company is producing the second sept pin, Shadow Mask which is the chief part of CRT in W, Monitor. Inside of the CRT pan, Shadow Mask leads the electronic beam to express the three primary colors; red, green, blue, and it is the core part to embody the colors. In the etching process, it produces this part with manufacturing by eroding the iron chloride. Even though the iron chloride is harmless to human body. it is necessary to diminish the amount of it on the view of preservation of environment. In addition, by studying the method of the dispossed liquid process, cutting down the manufacturing cost is a necessary task on the aspect of reconsideration of competitive business. This study shows the case that through the six sigma innovation activity, it reforms the following the former processing flow, and it reduces the amount of it by improving the efficiency of the iron chloride. By rationalization of the standard requirement cooperative company, it could cut down the manufacturing cost in the cooperative company, so it could promote the common profits.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.889-894
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• 2009

Accompanied by the rapid development of Computer Vision, Visual surveillance has achieved great evolution with more and more complicated processing. However there are still many problems to be resolved for robust and reliable visual surveillance, and the cast shadow occurring in motion detection process is one of them. Shadow pixels are often misclassified as object pixels so that they cause errors in localization, segmentation, tracking and classification of objects. This paper proposes a novel cast shadow removal method. As opposed to previous conventional methods, which considers pixel properties like intensity properties, color distortion, HSV color system, and etc., the proposed method utilizes observations about edge patterns in the shadow region in the current frame and the corresponding region in the background scene, and applies Laplacian edge detector to the blob regions in the current frame and the background scene. Then, the product of the outcomes of application determines whether the blob pixels in the foreground mask comes from object blob regions or shadow regions. The proposed method is simple but turns out practically very effective for Gaussian Mixture Model, which is verified through experiments.