• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.828-829
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• 2010

Rhenium-Iridium(Re-Ir) thin films were deposited onto the tungsten carbide(WC) molding core by sputtering system. The Re-Ir thin films on tungsten carbide molding core were analyzed by scanning electron microscope(SEM) and surface roughness. The Re-Ir coating technique has been intensive efforts in the field of coating process because the coating technique and process have been their feature, like hardness, high elasticity, adrasion resistance and mechanical stability and also have been applied widely the industrial and biomedical areas. In this report, tungsten carbide(WC) molding core was manufactures using high performance precision machining and the efforts of Re-Ir coating on the surface roughness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.428-428
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• 2007

최근 고화질 카메라폰이 경박단소화 되는 경향에 따라 Plastic렌즈 또는 구면 Glass렌즈만으로는 요구되는 광학적 성능 구현이 힘들기 때문에 비구면 Glass렌즈에 대한 요구가 증가하고 있다. 이러한 비구면 Glass렌즈는 일반적으로 초경합금 성형용 코어를 이용한 고온압축 성형방식으로 제작되어지기 때문에 코어면의 초정밀 연삭가공 및 코어면 코팅기술 개발이 시급한 상황이다. 한편, 대표적인 난삭재 Silicon Carbide(SiC)는 광학적 특성 및 기계적 특성, 전기적 특성 등 우수한 특성을 가진 재료로서 우주망원경, 레이저 광 및 X선 반사용 미러 등 다종, 다양한 용도로 이용되고 있으며 전기, 전자, 정보, 정밀기기의 급격한 발전으로 SiC의 수요가 급격히 증가하고 있다. 비구면 Glass렌즈 성형용 코어를 SiC소재로 제작할 경우 성형용 코어의 수명향상, 렌즈 생산원가의 절감 및 코팅 과정의 간소화 등의 다양한 장점을 가지므로 SiC를 이용한 성형용 코어의 나노 정밀도급 초정밀 연삭가공기술의 개발이 필요하다. 본 논문에서는 3 메가픽셀, 2.5배 광학 줌 카메라폰 모듈용 비구면 Glass렌즈 개발을 목적으로 실험계획법을 적용하여 초경합금 성형용 코어의 연삭조건을 규명하였다. 초경합금 비구면 성형용 코어의 초정밀 연삭가공조건 및 결과를 바탕으로 난삭재인 Silicon Cabide(SiC)의 연삭가공조건을 구하고 이를 이용하여 비구면 Glass렌즈 성형용 코어를 초정밀 연삭가공하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.251-252
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• 2007

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.676-677
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• 2011

Rhenium-Iridium(Re-Ir) thin films were deposited onto the tungsten carbide(WC) molding core by sputtering system. The Re-Ir thin films on tungsten carbide molding core were analyzed by scanning electron microscope(SEM) and surface roughness. The Re-Ir coating technique has been intensive efforts in the field of coating process because the coating technique and process have been their feature, like hardness, high elasticity, adrasion resistance and mechanical stability and also have been applied widely the industrial and biomedical areas. In this report, tungsten carbide(WC) molding core was manufactures using high performance precision machining and the efforts of Re-Ir coating on the surface roughness.

• Korean Journal of Optics and Photonics
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• v.18 no.5
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• pp.362-366
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• 2007

In this research, the optimal grinding condition has been obtained by design of experiment (DOE) fur the development of aspheric lens for the 3 Mega Pixel, 2.5x optical zoom camera-phone module. Also, the tungsten carbide (WC) mold was processed by the method of ultra precision grinding under this optimal grinding condition. The influence of diamond-liked carbon (DLC) coating on form accuracy (PV) and surface roughness (Ra) of the mold was evaluated through measurements after DCL coating using ion plating on the ground mold. Also, aspheric glass lenses were molded, some before DLC coating of the mold and some after the DLC coating. The optical characteristics of each sample, molded by the different molds, were compared with each other.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.64-71
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• 2009

Cylindrical lens core for optical transceiver was designed and machined. With the lens design data, WC asymmetric core surface data were generated for non-revolutional ultra-precision grinding. Grinding process for optimum machining conditions of target surface was studied in terms of surface roughness and form profile. We used experimental results to optimize turbine speed, feed-rate and depth of cut with durable grinding wheel wear. Ground WC cores were measured contact type profilers and verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.7
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• pp.1296-1302
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• 2016

A hardware implementation of ultra-lightweight block cipher algorithm PRESENT that was specified as a block cipher standard for lightweight cryptography ISO/IEC 29192-2 is described in this paper. Two types of crypto-core that support master key size of 80-bit are designed, one is for encryption-only function, and the other is for encryption and decryption functions. The designed PR80 crypto-cores implement the basic cipher mode of operation ECB (electronic code book), and it can process consecutive blocks of plaintext/ciphertext without reloading master key. The PR80 crypto-cores were designed in soft IP with Verilog HDL, and they were verified using Virtex5 FPGA device. The synthesis results using $0.18{\mu}m$ CMOS cell library show that the encryption-only core has 2,990 GE and the encryption/decryption core has 3,687 GE, so they are very suitable for IoT security applications requiring small gate count. The estimated maximum clock frequency is 500 MHz for the encryption-only core and 444 MHz for the encryption/decryption core.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.19-20
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• 2010

• Journal of the Korean Society for Precision Engineering
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• v.33 no.11
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• pp.893-898
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• 2016

Plastic array lens are cheap to manufacture; however, plastic is not resistant to high temperatures and moisture. Optical glass represents a better solution but is a more-expensive alternative. Glass array lens can be produced using lithography or precision-molding techniques. The lithography process is commonly used, for instance, in the semiconductor industry; however, the manufacturing costs are high, the processing time is quite long, and spherical aberration is a problem. To obtain high-order aspherical shapes, mold-core manufacturing is conducted through ultra-precision grinding machining. In this paper, a $4{\times}1$ mold core was manufactured using an ultra-precision machine with a jig for the injection molding of an aspherical array lens. The machined mold core was measured using the Form TalySurf PGI 2+ contact-stylus profilometer. The measurement data of the mold core are suitable for the design criterion of below 0.5 um.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.57-62
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• 2009

Recently, with the increasing lightness and miniaturization of high resolution camera phones, the demand for aspheric glass lens has increased because plastic and spherical lens are unable to satisfy the required performance. An aspheric glass lens is fabricated by the high temperature and pressure molding using a tungsten carbide molding core, so precision grinding technology for the molding core surface are required. This paper reports a development of feedrate control grinding method for aspherical molding core using parallel grinding method. A plane molding core was ground using conventional and feedrate control grinding method. The performance of the feedrate control method was evaluated by measurement of surface roughness. The result indicated that the average surface roughness was reduced to 1.5 nm, which is more efficient than the conventional grinding method.