• Title/Summary/Keyword: microlens

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Fabrication of Anti-Moiré Filter Using Multi-Array Needle Coating for LED Screens (다중 배열 니들 코팅을 이용한 LED 스크린용 Anti-Moiré 필터 제작)

  • Jeon, Kyungjun;Lee, Jinyoung;Park, Jongwoon
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.1
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    • pp.77-82
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    • 2021

  • Using a multi-array needle module developed for coating of high-density cylindrical microlens array (C-MLA), we have fabricated an anti-Moiré filter for LED screens. The Moiré phenomenon appears due to the interference between the array pattern of image sensors in a camera and the non-emission area (grid pattern) of a LED screen. To suppress it, we have employed poly(methyl methacrylate) (PMMA) and coated it on a glass substrate in the form of a grid and non-grid (parallel lines). We have rotated the needle module in order to increase the number of C-MLAs. With this scheme, we have fabricated the 150 mm × 150 mm anti-Moiré filters where 836 microlens lines are formed. They show the average width of 255.4 ㎛, the average distance between CMLs of 94.6 ㎛, and C-MLA width non-uniformity of 4.7%. We have shown that the Moiré patterns still appear in the presence of the parallel (non-grid)-type filter, whereas they disappeared completely by the grid-type filter. It is due to the fact that the Moiré patterns are diffused more effectively by the grid-type C-MLA.

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Fabrication of Solution-Based Cylindrical Microlens with High Aspect Ratio (고종횡비를 갖는 용액기반 원통형 마이크로렌즈 제조)

  • Jeon, Kyungjun;Lee, Jinyoung;Park, Jongwoon
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.1
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    • pp.70-76
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    • 2021

  • A cylindrical microlens (CML) has been widely used as an optical element for organic light-emitting diodes (OLEDs), light diffusers, image sensors, 3D imaging, etc. To fabricate high-performance optoelectronic devices, the CML with high aspect ratio is demanded. In this work, we report on facile solution-based processes (i.e., slot-die and needle coatings) to fabricate the CML using poly(methyl methacrylate) (PMMA). It is found that compared with needle coating, slot-die coating provides the CML with lower aspect ratio due to the wide spread of solution along the hydrophilic head lip. Although needle coating provides the CML with high aspect ratio, it requires a high precision needle array module. To demonstrate that the aspect ratio of CML can be enhanced using slot-die coating, we have varied the molecular weight of PMMA. We can achieve the CML with higher aspect ratio using PMMA with lower molecular weight at a fixed viscosity because of the higher concentration of PMMA solute in the solution. We have also shown that the aspect ratio of CML can be further boosted by coating it repeatedly. With this scheme, we have fabricated the CML with the width of 252 ㎛ and the thickness of 5.95 ㎛ (aspect ratio=0.024). To visualize its light diffusion property, we have irradiated a laser beam to the CML and observed that the laser beam spreads widely in the vertical direction of the CML.

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Development of Microlens Array for Maskless Lithography Application (Maskless lithography 응용을 위한 마이크로렌즈 어레이 개발)

  • Nam, Min-Woo;Oh, Hae-Kwan;Kim, Geun-Young;Seo, Hyun-Woo;Wei, Chang-Hyun;Song, Yo-Tak;Yang, Sang-Sik;Lee, Kee-Keun
    • Journal of the Microelectronics and Packaging Society
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    • v.16 no.4
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    • pp.33-39
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    • 2009

  • A microlens array (MLA) was developed based on the wet-etched quartz substrate and coating of UV adhesive on the substrate for maskless lithography application. The developed MLA has the focal length of ${\sim}45\;{\mu}m$ and the spot size of ${\sim}1\;{\mu}m$. The spot size of the focused beam passing through the MLA was detected by CCD camera, and its intensity was monitored by beam profiler. Uniform spots with nearly identical intensities were observed on the focal plane when a beam passes through the fabricated MLA. The focal length was varied depending on thickness of the coated UV adhesive. The thicker the thickness of the UV adhesive was, the shorter the focal length of the MLA was. With a general mask aligner, UV beam focusing was tested onto photoresist (PR). The beams were well focused onto PR when UV passes through the MLA. Depending on the variable distances from the MLA, beam sizes onto PR were controlled. Even at high temperature for a long time, the performances of the MLA were not changed.

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Fabrication of Micro-Lens Array with Long Focal Length for Confocal Microscopy (공초점 현미경용 장초점 마이크로렌즈 제작)

  • Kim, Gee-Hong;Lim, Hyung-Jun;Jeong, Mi-Ra;Lee, Jae-Jong;Choi, Kee-Bong;Lee, Hyung-Seok;Do, Lee-Mi
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.4
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    • pp.472-477
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    • 2011

  • This paper shows the method of fabrication of a micro lens array comprised of a Nipkow disk used in a large-area, high-speed confocal microscopy. A Nipkow disk has two components, a micro lens array disk and a pinhole array disk. The microlens array focuses illumination light onto the pinhole array disk and redirects reflected light from a surface to a sensor. The micro lens which are positioned in order on a disk have a hemispheric shape with a few tens of micron in diameter, and can be fabricated by a variety of methods like mechanical machining, semiconductor process, replication process like imprinting process. This paper shows how to fabricate the micro lens array which has a long focal length by reflow and imprinting process.

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