• 한국광학회:학술대회논문집
• /
• 한국광학회 2002년도 제13회 정기총회 및 2002년도 동계학술발표회
• /
• pp.98-99
• /
• 2002

• 산업과 과학
• /
• 제2권4호
• /
• pp.28-35
• /
• 2023

본 논문에서는 적응형 전조등 시스템 규정 중 일반도로 모드, 고속도로 모드, 젖은도로 모드를 만족하는 배광의 형성을 위한 회절 광학 소자를 설계하였으며, 이를 GDSII 스트림 형식의 파일로 도출하였다. 회절 광학 요소를 통해 형성된 배광의 유효성 및 백색광 구현 여부 확인을 위하여 각각 Field Tracing, Ray Tracing 기반의 시뮬레이션을 진행하여 변환빔 측정점에 대한 위치 요구사항 및 광도 요구사항의 만족을 확인하였다. 본 연구를 기반으로 적응형 전조등을 구현하는 경우, 광도의 대비 재현 및 단순한 구조의 적응형 전조등 시스템 구현이 가능할 것으로 예상된다.

• 소성∙가공
• /
• 제15권1호
• /
• pp.3-8
• /
• 2006

The demand fer small and high-capacity optical data storage devices has rapidly increased. The areal density of optical disk is increased by using higher numerical aperture objective lens and shorter wavelength source. A wafer-scale stacked micro objective lens with a numerical aperture of 0.85 and a focal length of 0.467mm for the 405nm blue- violet laser was designed and fabricated. A diffractive optical element (DOE) was used to compensate the spherical aberration of the objective lens. Among the various fabrication methods for micro DOE, the UV-replication process is more suitable fur mass-production. In this study, an 8-stepped DOE pattern as a master was fabricated by photolithography and reactive ion etching process. A flexible mold was fabricated for improving the releasing properties and shape accuracy in UV-replication process. In the replication process, the effects of exposing time and applied pressure on the replication quality were analyzed. Finally, the surface profiles of master, mold and molded pattern were measured by optical scanning profiler. The geometrical deviation between the master and the molded DOE was less than $0.1{\mu}m$. The diffraction efficiency of the molded DOE was measured by DOE efficiency measurement system which consists of laser source, sample holder, aperture and optical power meter, and the measured value was $84.5\%$.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
• /
• pp.35-40
• /
• 2005

The demand for small and high-capacity optical data storage devices has rapidly increased. The areal density of optical disk is increased using higher numerical aperture objective lens and shorter wavelength source. A wafer-scale stacked micro objective lens with a numerical aperture of 0.85 and a focal length of 0.467mm for the 405nm blue- violet laser was designed and fabricated. A diffractive optical element (DOE) was used to compensate the spherical aberration of the objective lens. Among the various fabrication methods for micro DOE, the UV-replication process is more suitable for mass-production. In this study, an 8-stepped DOE pattern as a master was fabricated by photolithography and reactive ion etching process. A flexible mold was fabricated for improving the releasing properties and shape accuracy in UV-molding process. In the replication process, the effects of exposing time and applied pressure on the replication quality were analyzed. Finally, the shapes of master, mold and molded pattern were measured by optical scanning profiler. The deviation between the master and the molded DOE was less than 0.1um. The efficiency of the molded DOE was measured by DOE efficiency measurement system which consists of laser source, sample holder, aperture and optical power meter, and the measured value was $84.5\%$.

• 한국광학회지
• /
• 제31권6호
• /
• pp.281-289
• /
• 2020

본 논문은 하이브리드 굴절/회절광학소자를 이용한 초슬림 모바일 카메라 렌즈를 보고한다. 먼저 앞서 보고된 23개의 광학 설계 사양 분석을 통해 전장길이(total track length) 최소화를 위하여, 광시야 렌즈 설계에서 일반적으로 적용되는 음(-)의 렌즈를 제1렌즈로 사용하는 리트로포커스(retrofocus) 타입이 아닌, 양(+)의 렌즈가 제일 먼저 선행하는 텔레포토(telephoto) 타입을 선택하였다. 이후 초기 최적 설계 및 제르니케 다항식 기반 수차 분석을 통한 보정 설계를 진행하였으며, 보정 설계 과정에서 잔여 구면색수차(chromatic spherical aberration)의 효과적 제거를 위하여 굴절 및 회절이 결합된 하이브리드 렌즈 1매를 적용하였다. 적용된 최종 설계는 하이브리드 렌즈 1매 포함 총 6매의 렌즈를 이용하여 F/2.0, 화각 90°, 유효초점길이 2.23 mm, 전장길이 3.7 mm를 달성하였고, 결과적으로 1.7의 낮은 전장길이 대 초점길이 비 즉, 텔레포토비(telephoto ratio)를 달성하였다. 동일 전장길이를 갖는 하이브리드 렌즈 미적용 비교 설계 대비, 공간주파수 180 cycles/mm에서 MTF 값이 중심 시야에서는 63%에서 71~73%로 약 8~10% 개선되었고, 0.5, 0.7, 0.9 시야에서도 2~3% 개선되었다. 또한, 가공성 및 회절 패턴에 의한 산란 등을 고려하였을 때 조리개에 위치한 렌즈가 하이브리드 렌즈로 적절함을 알 수 있었고, 이 경우 2개의 회절존으로도 성능 개선이 확인되었다.

• Journal of the Optical Society of Korea
• /
• 제10권3호
• /
• pp.105-111
• /
• 2006

A novel image quality evaluation method, which is based on combination of the rigorous grating diffraction theory and the ray-optic method, is proposed. It is applied for design optimization and, tolerance analysis of optical imaging systems implementing diffractive optical elements (DOE). The evaluation method can predict the quality and resolution of the image on the image sensor plane through the optical imaging system. Especially, we can simulate the effect of diffraction efficiencies of DOE in the camera lenses module, which is very effective for predicting different color sense and MTF performance. Using this method, we can effectively determine the fabrication tolerances of diffractive and refractive optical elements such as the variations' in profile thickness, and the shoulder of the DOE, as well as conventional parameters such as decenter and tilt in optical-surface alignments. A DOE-based 2M-resolution camera lens module designed by the optimization process based on the proposed image quality evaluation method shows ${\sim}15%$ MTF improvement compared with a design without such an optimization.

• Journal of the Optical Society of Korea
• /
• 제13권1호
• /
• pp.75-79
• /
• 2009

A four beam interference optical system for laser micro structuring using a pulse laser was demonstrated. The four beam interference optical system using a pulse laser(picosecond laser) can fabricate micro structure on mold material(NAK80) directly. Micro structure on the polymer can be reproduced economically by injection molding of the micro structure on the mold material. The four beam interference optical system was composed by the DOE(Diffractive Optical Element) and two lenses. The laser intensity distribution of four beam interference was explained by an interference optics point of view and by the image optics point of view. We revealed that both views showed the same result. The laser power distribution of a $1{\mu}m$ peak pattern was made by the four beam interference optical system and measured by the objective lens and CCD. A $1{\mu}m$ pitch dot pattern on the mold material was fabricated and measured by SEM(Scanning Electron Microscopy).

• 한국정보통신학회논문지
• /
• 제8권8호
• /
• pp.1810-1817
• /
• 2004

본 연구에서는 CD, DVD의 기록 및 재생기에 사용되는 광 픽업 장치에서의 빔의 특성을 좋아지게 하기 위하여 DOE(회절광학소자)를 무족화(apodization)와 첨예화의 두 가지 방법으로 설계하여 최적화 알고리즘으로 심플렉스법을 적용하여 기존 광 픽업 장치와 비교 분석하였다. 분석된 결과 무족화에 있어서 기존 광 픽업 장치와 비교하여 2차 피크와 3차 피크는 39%, 63%로 억제되어 현저한 효과를 볼 수 있었고, 첨예화에서는 1차 피크의 폭이 4.8% 줄일 수 있었다. 그러나 이 역시 2차 피크가 커지는 부작용이 동반되는데 광 픽업 장치가 2차 피크의 영향이 적은 환경에서는 지터특성의 개선이 있을 것으로 기대하지만 1차와 2차 피크가 복합적으로 영향을 미치는 경우에는 광시스템에 대한 면밀한 고려하면, 원형창의 경우 단일 슬릿에 비하여 2차 피크의 밝기가 37%에 불과하여 실제의 산업현장에서 2차 피크를 무시하는 것을 고려하면 4.8%의 폭을 줄여 지터 특성이 개선되었다.

• 한국정밀공학회지
• /
• 제33권10호
• /
• pp.845-850
• /
• 2016

A direct laser lithography system is widely used to fabricate various types of DOEs (Diffractive Optical Elements) including lenses made as CGH (Computer Generated Hologram). However, a parametric study that uniformly and precisely fabricates the diffractive patterns on a large area (up to $200mm{\times}200mm$) has not yet been reported. In this paper, four parameters (Focal Position Error, Intensity Variation of the Lithographic Beam, Patterning Speed, and Etching Time) were considered for stabilization of the direct laser lithography system, and the experimental results were presented.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2004년도 하계학술발표회
• /
• pp.110-111
• /
• 2004