• 대한기계학회논문집 C: 기술과 교육
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• 제1권1호
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• pp.13-19
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• 2013

$F{\theta}$ 렌즈는 레이저 프린터의 LSU(Laser Scanning Unit)의 중요 부품으로서 $F{\theta}$ 렌즈를 통과한 주사빔의 상 위치는 주사빔의 렌즈 입사각에 비례한다. 본 논문에서는 당사에서 개발한 A4 사이즈용 $F{\theta}$ 렌즈를 설계, 제작하고 보정하는 과정을 소개하였다. 렌즈 개발에서 광학설계는 Zemax를 사용하였고 주사빔의 주주사방향 및 부주사방향의 왜곡을 최소화 하기 위하여 렌즈면은 특수한 토릭면으로 하였다. 렌즈 금형은 1nm 의 분해능을 갖는 초정밀 가공기로 제작하였다. 렌즈 사출 후 성능을 평가하고 측정값과 설계값의 차이를 바탕으로 설계보정식을 유도하여 렌즈 금형을 수정하였다. 금형 수정 후 사출렌즈의 재측정 결과 초기 설계값에 가까운 성능을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1199-1200
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• 2013

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.383-384
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• 2008

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.370-375
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• 2002

Recently, the interest on micro optical parts has increased rapidly with the development of technology related to microsystems. Among the optical parts, micro lens is one of the most broadly used micro parts. To mass-produce the micro lenses, it is very effective to use the mold insert and injection molding process. There are many methods to fabricate the mold insert for micro lenses: electroforming, etching, mechanical micromachining and so on. In this study, we fabricated the mold insert for micro lenses using a micro ball endmill to apply mechanical micromaching method and analyzed the effect of main process parameters such as spindle speed, feed rate, dwell time on the processed surface. Then, using fabricated the mold insert we fabricated the micro lenses through injection molding process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.191-192
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• 2006

• 한국전기전자재료학회논문지
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• 제19권11호
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• pp.1050-1054
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• 2006

There have been intensive and continuous efforts in the field of DLC coating process because of their feature, like high hardness, high elasticity, abrasion resistance and chemical stability and have been applied widely the industrial areas. In this research, optimal grinding condition was investigated using Microlens Process Machine for the development of aspheric glass lens which is to be used for mobile phone module with 3 mega pixel and 2.5X optical zoom, and tungsten carbide(WC) mold cote was manufactured using high performance ultra precision machining and the effects of DLC coating on the form accuracy(PV) and surface roughness(Ra) of WC mold core was evaluated.

• 한국정밀공학회지
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• 제31권7호
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• pp.561-567
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• 2014

Precision injection mold is an essential element in order to manufacture small and precision plastic lenses used for phone camera. There are many critical factors to meet the requested specifications of high quality plastic lenses. One of the main issues to realize high quality is minimizing decenter value, which becomes more critical as pixel numbers increases. This study suggests the method to minimize decenter value by modifying ejecting structure of the mold. Decenter value of injection-molded lens decreased to 1 ${\mu}m$ level from 5 ${\mu}m$ by applying suggested ejecting method. Also, we also developed BIS (Built-in Sensor) based smart mold system, which has pressure and temperature sensors inside of the mold. Pressure and temperature profiles from cavities are obtained and can be used for deduction of optimal injection molding condition, filling imbalance evaluation, status monitoring of injection molding and prediction of lens quality.

• 한국정밀공학회지
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• 제29권3호
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• pp.261-265
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• 2012

In this study, glassy carbon was ground for lens core of glass mold press. Ultraprecision grinding process was applied for machining of core surfaces. During the process, brittle crack occurred because of hard-brittleness of glassy carbon. Author investigated optimized grinding conditions from the viewpoint of ductile mode grinding. Geometrical undeformed chip thickness was adopted for critical chip thickness that enables crack free surface. Machined cores are utilized for biaspheric glass lens fabrication and surfaces of lens were compared for verification of ground surface.

• 한국공작기계학회논문집
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• 제17권5호
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• pp.82-88
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• 2008

Conventional aspherical lens polishing methods by the small tool polishing use aspherical profile and the trajectory of the polishing tool is also controlled. In this paper, new full contact polishing mechanism is suggested to polish aspherical glass lens mold by both airbag polishing tool and eccentric motion. Full contact concept by airbag polishing tool and no position control make the easy polishing setup and do not need aspherical design profile. An aspherical lens polishing machine was made for this study and a verification experiment was performed for surface roughness improvements.

• 한국정밀공학회지
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• 제33권11호
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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.