• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.60-65
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• 2019

In this paper, the hybrid illumination system for effectively detecting surface defects in steel plate with lowcontrast, non-uniformity and featureless is designed based on illuminance uniformity. First of all, characteristics of steel plate defects were considered and typical inspection illumination system is implemented. Optimum illumination parameters for uniformly illuminating an inspection area in the typical illumination system are selected based on the illuminance uniformity and illuminance distribution measurement. The illuminance uniformity and illuminance distribution are measured using an illuminometer based on the arduino. Through illuminance distribution analysis of the typical illumination, an hybrid illumination is designed by fusing bi-directional illumination and coaxial illumination. The hybrid illumination showed higher uniformity ratio and illuminance distribution than the typical illuminations. The hybrid illumination system showed the ability to uniformly illuminate the entire inspection region of steel plate surface.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2512-2517
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• 2007

Effect of natural convention for hot plate surface temperature uniformity was studied by experiments that were adjusted height of chamber and temperature difference. The hot plate chamber is composed of the hot plate and the upper heater and adiabatic vertical wall. The hot plate diameter is 220mm and maintains temperature at $150^{\circ}C$. Flow pattern compares with surface temperature and confirms that natural convection affects on temperature uniformity of hot plate surface. In case, temperature non-uniformity of hot plate surface is due to heater pattern, lots of weak and small flow cells more improve temperature uniformity than stronger flow cells or non-developing flow cell. Improve temperature uniformity $1.2^{\circ}C$ when developing weak and small flow cells.

• Journal of the Korean institute of surface engineering
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• v.56 no.1
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• pp.94-103
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• 2023

The effects of carburizing pressure and gas ratio on vacuum carburizing properties (uniformity and surface characteristics) have been studied through the analyses of carbon concentration, hardness, surface color, surface roughness and type of carbon bonding. AISI 4115 steel specimens were carburized with various pressures (1, 5, and 10 Torr) at different locations (P₁, P₂, P₃, P₄, P₅, and P₆) inside a furnace held at 950 ℃. Since the carburizing pressure represents the density of the carburizing gas, it plays an important role in improving the carburizing uniformity according to locations in the furnace. As the carburizing pressure increased, the carburizing uniformity according to the sample location was improved, but the surface of the carburized specimen was discolored due to the residual acetylene gas, which does not contribute to the carburizing reaction. Therefore, the carburizing uniformity and surface discoloration have been improved by injecting acetylene gas (carburizing gas) and nitrogen gas (non-reactive gas) in a specific ratio.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.4
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• pp.309-313
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• 2006

Pad surface characteristics such as roughness, groove and wear rate of pad have a effect on the within wafer non-uniformity(WIWNU) in chemical mechanical polishing(CMP). Although WIWNU increases as the uniformity of roughness(Rpk: Reduced peak height) becomes worse in an early stage of polishing time, WIWNU decreases as non-uniformity of the Rpk value. Also, WIWNU decreases with the reduction of the pad stiffness, though original mechanical properties of pad are unchanged by the grooving process. In addition, conditioning process causes the inequality of pad wear during in CMP. The profile of pad wear generated by the conditioning process has a significant effect on the WIWNU. These experiments results could help to understand the effect of pad surface characteristics in CMP.

• Design & Manufacturing
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• v.8 no.2
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• pp.41-45
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• 2014

Automated polishing apparatus based on the research have been developed. The research is improvement of polishing process for surface quality and uniformity improvement of preform injection mold core. Surface quality of preform core have influence on ejecting and product quality after injection molding. Thus, the current being made by hand to automate the polishing process, the surface of the preform to improve the quality and uniformity improvement. First made a division by analyzing manual process a step-by-step. And draw a mechanism for converting mechanical movement. Automated polishing apparatus for preform core was developed, through which shortens production time and were able to secure the safety of the worker.

• Laser Solutions
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• v.11 no.1
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• pp.1-6
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• 2008

We proposed new light guide panel (LGP) fabrication method exploiting laser-processed inner scatterers and surface pattern. The proposed method has achieved LGP performance improvement in both brightness and uniformity. The inner scatterers and surface pattern of grid type were fabricated with a 2nd harmonic Nd:YAG pulse laser engraving system and a $CO_2$ laser scanning system, respectively. In the implementation of LGP, inner scatterers was arranged in accordance with linear or curved pattern with changing density and surface pattern was engraved on the surface of an inner-scatterers embedded LGP. The increase of scatterers' density and the use of surface patterns in both linear and curved pattern provided high luminance and uniformity enhancement. While thecurved pattern incorporated with increased scatterers' density and surface patterns yielded brightness improvement with preserving good uniformity, the linear pattern showed highly localized brightness near the light entrance of the LGP. We can also observe that the uniformity was mainly determined by pattern of inner scatterers, and the brightness was improved by the higher density and the utilization of surface patterns. From the results, the use of laser-processed inner and surface patterns can be a potential alternative for efficient and simple LGP fabrication method.

• Journal of the Semiconductor & Display Technology
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• v.3 no.3
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• pp.41-44
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• 2004

The aim of this study is the confirmation of the coating uniformity affected by the surface tension and wall attachment angle in a slit-coater model. In this work, we use the commercial code (Fluent) to solve the two-phase flow formed with air and photo resist numerically. The results show that the surface tension is the most important factor to determine the coating efficiency in the view of coating uniformity, and the coating uniformity is 2% for our slit-coater model and conditions. To improve the coating uniformity, it is in need of minimization of the sidewall effect of slit-coater.

• Journal of the Korean institute of surface engineering
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• v.18 no.3
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• pp.105-115
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• 1985

Lead-tin-copper ternary alloy electrodeposition is conducted onto the inner bore surface of plain bearings as an overlay in order to investigate the effect of slot width, current density and fluoboric acid concentration on the uniformity of overlay. The thickness of overlay is analyzed by means of current distribution resulting from the overvoltage of plating bath and the apparent distance between cathode and anode. The result demonstrate that the uniformity of overlay is remarkably dependent of the slot size and current density, but has little bearing on the fluoboric acid concentration over 100g/L. This present study indicates that uniform overlay is obtainable within the tolerable thickness of ${\pm}2{\mu}m$ by using the slot width of 22mm. The surface morphology examination also shows the important role of concentration polarization of the micro-uniformity of overlay. The micro-uniformity has improved at the low concentration polarization which resulted from operating at the low current density and high fluoboric acid concentration. The surface morphology of deposits exhibits the vivid pyramid crystalline in the plating condition of low concentration polarizatio and all deposits have columnar structure parallel to the applied electric field regardless of the electroplating condition used.

• Transactions on Electrical and Electronic Materials
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• v.18 no.1
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• pp.35-41
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• 2017

This study looks at optimizinge light redistribution to improve the overall illuminance uniformity of commercial IRED modules. To obtain uniform illumination over a prescribed rectangular area, a freeform surface lens was evaluated using TracePro. The LED light overall illuminance uniformity regulated in KSC 7658 was verified using Relux software. Experimental test results showed 0.81 overall illuminance uniformity for rectangular light distribution of LED lights having a radiation angle of $80^{\circ}$. After fabricating prototype IRED lights based on these simulation results, illuminance performance was observed when used as actual IRED lighting with a nighttime CCTV system. Image observation photographs of the prototype $80^{\circ}$ rectangular IRED lights confirmed that object images can be seen clearly owing to high overall illuminance uniformity, and that dark regions of the CCTV screen were not shown.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.517-518
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• 2011