• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1682-1683
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• 2011

Through-silicon microlens array has been implemented using glass thermal reflow process. Design, numerical analysis, fabrication, and measurement results are discussed. Microlenses with six different volumetric dimensions were successfully fabricated and characterized. Radius of curvature of each microlenses were measured with less than 1% deviation compared to calculated value. Measured average roughness of the microlens surface was 16.5 nm.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.104-107
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• 2007

An aspheric microlens array to improve the properties of multi optical probes was designed and fabricated. To generate multi optical probes with good qualities, a microlens array with the minimum spherical aberration was designed by ray tracing. Using the reflow process, a master pattern of aspheric microlens array was made and finally with the ultraviolet-imprinting (UV-imprinting) method, the aspheric microlens array was replicated. The reflow condition was optimized to realize the master pattern of the microlens array with the designed aspheric shape. The intensity distribution of the optical probes at the focal plane showed a diffraction-limited shape.

• 정보저장시스템학회논문집
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• 제2권1호
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• pp.1-6
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• 2006

An optical ROM card system which using an optical probe array generated by Talbot effect was proposed as new robust storage solution. To improve the optical density and to decrease the power consumption of the system, it is very important to make the spot sizes of optical probes smaller as well as to increase the optical efficiency from the light source to optical probes. In this study, a microlens illuminated aperture array for generating high efficiency optical probe away with small beam spot was designed and fabricated using monolithic lithography integration method. The maximum intensity of optical probes of microlens illuminated aperture array increased about 12 times of that of aperture array, and the full width half maximum of the optical probe at Talbot plane generated by microlens illuminated aperture array was $0.77{\mu}m$.

• 소성∙가공
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• 제15권1호
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• pp.34-41
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• 2006

Microlens arrays were fabricated by a modified LIGA process composed of the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, both hot embossing and microinjection molding processes have been successfully utilized with the fabricated mold insert. Replicated microlenses showed very good surface roughness with the order of 1 nm. The focal lengths of the injection molded microlenses were successfully estimated theoretically and also measured experimentally.

• 소성∙가공
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• 제13권3호
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• pp.236-241
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• 2004

UV-molded microlens arrays with high replication quality were fabricated using a parametric design method. It is important to maximize the replication quality, because one can obtain the replicated micro-optical components with desired properties by accurate control of the shape. In the present study, nickel mold inserts for microlens arrays with lenses having diameters between $3\mu\textrm{m}$ and $230\mu\textrm{m}$ were fabricated by electroforming process. An UV-molding system was designed and constructed, a simple technique to avoid micro-air bubbles was first suggested, and the effects of the compression pressure and UV-curing dose on the replication quality of UV-molded microlens arrays with a diameter of $14\mu\textrm{m}$ were examined experimentally. Finally, geometrical and optical properties of the replicated microlens arrays were measured and analyzed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
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• pp.23-28
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• 2005

Microlens arrays were fabricated using a modified LIGA process based on the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, the hot embossing and the microinjection molding processes have been successfully utilized with the fabricated mold insert. Fabricated microlenses showed good surface roughness than the mold insert. The focal lengths of the injection molded microlenses were successfully measured experimentally and also estimated theoretically.

• 한국광학회지
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• 제32권3호
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• pp.101-107
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• 2021

본 논문에서는 MLA (microlens array)를 이용한 자동차 커뮤니케이션 램프 설계 방안에 대한 연구를 진행하였다. 자율주행기술의 발전으로 보행자와 차량 간의 소통을 위한 커뮤니케이션 램프가 자동차에 필요하게 되었다. 광학계의 크기를 줄이고, 높은 광량을 확보하기 위해 MLA를 사용하여 커뮤니케이션 램프 광학계를 설계하였다. 또한, 기울어진 지면에서 선명한 image를 확보하기 위해 중첩방안을 고려하여 설계를 진행하였다. 이후 중첩 전 MLA 광학계와 성능 비교를 통해 향상된 성능을 확인하였다.

• 한국전기전자재료학회논문지
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• 제26권10호
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• pp.745-753
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• 2013

Performance of organic light-emitting diodes incorporating microlens array was simulated using a Light Tools software. Use of microlens array can help the light to escape out of the device. We simulated a reference device that is consisted of reflection layer, emissive layer, and flat transparent substrate. And in this reference device, outcoupled efficiency of 22% was obtained. Several shapes of microlens were applied such as hemisphere, trapezoid, cone, and rectangular parallelepiped. The results showed the improvement of outcoupled efficiency of the device with microlens compared to that of the reference one. And from the analyses of the simulated data, the obtained appropriate shape of microlens is hemisphere, and the improvement of the device with hemispherical lens is 57% higher than that of the reference one.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.500-500
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• 2013

특정한 유기 물질에 전류를 인가했을 때 발광을 하는 특성을 이용한 Organic Light Emitting Diode (OLED)는 뛰어난 색재현성, 적은 전력소모, 간단한 제조공정, 넓은 시야각 등으로 인해 PDP, LCD, LED에 이은 차세대 디스플레이 소자로 많은 관심을 받고 있다. 하지만 OLED는 각기 다른 굴절률을 가지는 다층구조로 되어있어 실질적으로 소자 밖으로 나오는 빛은 원래 생성된 빛의 20% 정도 밖에 되지 않는다. 이러한 광 손실을 줄이기 위해 Photonic Crystal (PC)이나 마이크로 렌즈 어레이(MLA) 부착 등과 같이 특정한 크기를 갖는 주기적인 나노 구조물을 이용한 광추출 효율 상승 방법은 특정 파장의 빛에서만 효과가 있는 한계가 있었으며 고가의 공정과정을 거쳐야 했으므로 OLED 소자의 가격 향상에 일조하였다. 이의 해결을 위해 본 연구는 유리기판 위에 랜덤한 분포를 가지는 나노 구조물 제작 공정법을 제안한다. 먼저 유리기판 위에 스퍼터로 금속 박막을 입혀 이를 Rapid thermal annealing (RTA) 공정을 이용하여 랜덤한 분포의 Island를 가지는 마스크를 제작하였다. 그 후 플라즈마 식각을 이용하여 유리기판에 나노 구조물을 형성하였고 기판 위에 남아있는 마스크는 Ultrasonic cleaning을 이용하여 제거하였다. 제작된나노구조물은 200~300 nm의 높이와 약 200 nm 폭을 가지고 있다. 제작된 유리기판의 OLED 소자로의 적용가능성을 알아보기 위한 광학특성 조사결과는 300~900 nm의 파장영역에서 맨유리와 거의 비슷한 수직 투과율을 보이면서 최대 50%정도의 Diffusion 비율을 나타내고 있고 임계각(41도) 이상의각도에서 인가된 빛의 투과율에 대해서도 향상된 결과를 보여주고 있다. 제안된 공정의 전체과정 기존의 PC, MLA 등의 공정에 비해 난이도가 쉽고 저가로 진행이 가능하며 추후 OLED 소자에 적용될 시 대량생산에 적합한 후보로 보고 있다.

• 소성∙가공
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• 제18권4호
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• pp.310-316
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• 2009

Micro lens array(MLA) is widely used in information technology(IT) industry fields for various applications such as a projection display, an optical power regulator, a micro mass spectrometer and for medical appliances. Recently, MLA have been fabricated and developed by using a reflow method having the processes of micro etching, electroplating, micro machining and laser local heating. Laser thermal relaxation method is introduced in marking of microdots on the surface of densified glass. In this paper, we have proposed a new direct fabrication process using UV laser local thermal-expansion(UV-LLTE) and investigated the optimal processing conditions of MLA on the surface of negative photo-resist material. We have also studied the 3D shape of the micro lens obtained by UV laser irradiation and the optimal process conditions. And then, we made chrome mold by electroplating. After that, we made MLA using chrome mold by hot embossing processing. Finally, we have measured the opto-physical properties of micro lens and then have also tested the possibility of MLA applications.