• Title/Summary/Keyword: Micro Lens

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A study on the fabrication method of middle size LGP using continuous micro-lenses made by LIGA reflow

  • Kim, Jong-Sun;Ko, Young-Bae;Hwang, Chul-Jin;Kim, Jong-Deok;Yoon, Kyung-Hwan
    • Korea-Australia Rheology Journal
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    • v.19 no.3
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    • pp.171-176
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    • 2007
  • LCD-BLU (Liquid Crystal Display-Back Light Unit) of medium size is usually manufactured by forming numerous dots with $50{\sim}300\;{\mu}m$ in diameter by etching process and V-grove shape with $50\;{\mu}m$ in height by mechanical cutting process. However, the surface of the etched dots is very rough due to the characteristics of the etching process and V-cutting needs rather high cost. Instead of existing optical pattern made by etching and mechanical cutting, 3-dimensional continuous micro-lens of $200\;{\mu}m$ in diameter was applied in the present study. The continuous micro-lens pattern fabricated by modified LIGA with thermal reflow process was tested to this new optical design of LGP. The manufacturing process using LIGA-reflow is made up of three stages as follows: (i) the stage of lithography, (ii) the stage of thermal reflow process and (iii) the stage of electroplating. The continuous micro-lens patterned LGP was fabricated with injection molding and its test results showed the possibility of commercial use in the future.

Fabricating a Micro-Lens Array Using a Laser-Induced 3D Nanopattern Followed by Wet Etching and CO2 Laser Polishing

  • Seung-Sik Ham;Chang-Hwam Kim;Soo-Ho Choi;Jong-Hoon Lee;Ho Lee
    • Journal of the Korean Society of Industry Convergence
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    • v.26 no.4_1
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    • pp.517-527
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    • 2023
  • Many techniques have been proposed and investigated for microlens array manufacturing in three-dimensional (3D) structures. We present fabricating a microlens array using selective laser etching and a CO2 laser. The femtosecond laser was employed to produce multiple micro-cracks that comprise the predesigned 3D structure. Subsequently, the wet etching process with a KOH solution was used to produce the primary microlens array structures. To polish the nonoptical surface to the optical surface, we performed reflow postprocessing using a CO2 laser. We confirmed that the micro lens array can be manufactured in three primary shapes (cone, pyramid and hemisphere). Compared to our previous study, the processing time required for laser processing was reduced from approximately 1 hour to less than 30 seconds using the proposed processing method. Therefore, micro lens arrays can be manufactured using our processing method and can be applied to mass productionon large surface areas.

Generation of Lens surface by moving mask lithography (가변 속도 이동식 마스크를 이용한 렌즈 곡면 형성)

  • Lee Joon-Sub;Park Woo-Jae;Song Seok-Ho;Oh Cha-Hwan;Kim Pill-Soo
    • Korean Journal of Optics and Photonics
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    • v.16 no.6
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    • pp.508-515
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    • 2005
  • We propose a fabrication method for refractive lens by variable velocity moving mask lithography and slit pattern. Distribution of exposure dose should be controlled for the curved photoresist surface that works as a refractive surface. We analyze theoretically the distribution of exposure dose by change of moving velocity, moving direction of mask and the shape of mask pattern, and confirm for the curved surface experimentally. The lens could have sag height of a few of hundreds ${\mu}m$, by using thick photoresist or Deep RIE process.

Machinability in Micro-precision Machining of Ni-Plated Layer by Diamond Tool (다이어몬드 공구를 이용한 Ni 도금층의 정밀미세가공 시 절삭성)

  • Kim, Seon-Ah;Park, Dong-Sam
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.18 no.6
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    • pp.636-641
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    • 2009
  • Recently, expansion of micro-technology parts requires micro-precision machining technology. Micro-groove machining is important to fabricate micro-grating lens and many micro-parts such as microscope lens, fluidic graphite channel etc. Conventional groove fabrication methods such as etching and lithography have some problems in efficiency and surface integrity. But, mechanical micromachining methods using single crystal diamond tools can reduce these problems in chemical process. For this reason, microfabrication methods are expected to be very efficient, and widely studied. This study deals with machinability in micro-precision V-grooves machining of nickel plated layer using non-rotational single crystal diamond tool and 3-axis micro stages. Micro V-groove shape, chip formation and tool wear were investigated for the analysis of machinability of Ni plated layer.

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OPTICAL PROPERTIES AND TOPOLOGICAL CONFIGURATION OF CAUSTICS OF MICRO GRAVITATIONAL LENSES

  • Chang, Kyong-Ae
    • Journal of The Korean Astronomical Society
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    • v.24 no.1
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    • pp.1-12
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    • 1991
  • The mathematical properties of gravitational lens equations are examined in the frame work of gravitational micro-lensing effects. The caustics of the gravitational lens may be defined in terms of "cusp" and "folding" in general. In some cases for overfocussing, however, the critical curves (caustics) have no cusp and no folding. If the observer is in the overfocussed region, he may not see any lensed image.

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