• Current Optics and Photonics
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• v.5 no.5
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• pp.506-513
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• 2021

An arrayed diffractive optical element design for the beam-shaping of a multi-array light source is proposed. This is an essential device for recent optical security and face recognition applications. In practice, we devise a DC noise reduction technique featuring high fabrication error tolerance regarding the multi-array light source diffractive optical elements, as a necessary part of the proposed design method. The spherical diverging illumination leads to DC-conjugate noise spreading. The main idea is tested experimentally, and the multi-array light source diffraction pattern is investigated numerically.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.45-46
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• 2013

• Journal of the Optical Society of Korea
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• v.1 no.2
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• pp.74-80
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• 1997

300mm F/4.0 telephotolens with diffractive hybrid lens was designed, and its optical performance was tested and compared with a traditional lens system. DOE(Diffractive Optical Element) reconstructs wavefronts using wave phenomena of light to focus the incident light onto the focal point and has negative Abbe number while a traditional lens uses geometrical phenomena of light and has positive Abbe number. Therefore, a diffractive hybrid lens containing both refractive and diffractive elements can remarkably correct chromatic aberration and spherical aberration of an optical system. We investigated and analyzed the optical properties of a diffractive hybrid lens for the visible spectrum, and we used a difractive hybrid lens to design and evaluate a 300mm F/4.0 telephotolens without the special LD(Low Dispersive) glass lens which is costly and difficult to manufacture. Most traditional telephotolenses use the special LD glass for chromatic aberration correcton. Optical performance tests such as resolution and characteristics of aberration of both lens systems using a diffractive hybrid lens and traditional lens were performed.

• Optical Science and Technology
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• v.8 no.2
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• pp.22-26
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• 2004

회절 광학 소자(Diffractive optical element)는 광학 시스템에 있어서 광을 조절하기 위하여 굴절(refraction) 또는 반사(reflection)보다는 주기 구조(periodic structures)에 의한 회절(diffraction)을 이용한 소자라 할 수 있다. DOE의 장점으로는 수차(aberration)가 없는 point-to-point 이미지가 가능하며 광 power를 사용한 평판(flat subface)이 가능하고 비구면과 같은 수차 조절이 가능하다. 단점으로는 HOE(Hologram Optical Element: DOE의 일종)의 수차가 이 구조의 특정 파장에서 나타나고 가시영역의 일정 영역에서 매우 분산적 (dispersive)이다. 또한 상대적으로 시장의 성장에 비하여 찾는 고객의 수가 적다는 점이다.(중략)

• Current Optics and Photonics
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• v.8 no.1
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• pp.72-79
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• 2024

Recent flat-panel displays have become increasingly complicated to facilitate multiple display functions. In particular, the form of multilayered architectures for next-generation displays makes precise three-dimensional alignment of multiple panels a challenge. In this paper, a diffractive optical alignment marker is proposed to address the problem of three-dimensional alignment of distant dual panels beyond the depth-of-focus of a vision camera. The diffractive marker is effective to analyze the positional correlation of distant dual panels. The possibility of diffractive alignment in multilayer display fabrication is testified with numerical simulation and a proof-of-concept experiment.

• Journal of the Semiconductor & Display Technology
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• v.18 no.2
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• pp.58-62
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• 2019

Diffractive Optical Elements(DOEs) diffracts incident light using the diffraction phenomenon of light to generate a desired diffraction image. In recent years, the use of diffraction optics, which can replace existing refractive optical elements with flat plates, has been increased by implementing various optical functions that could not be implemented in refractive optical devices and by becoming miniaturized and compacted optical elements. Direct laser lithography is typically used to effectively fabrication such a diffractive optical element in a large area with a low process cost. In this study, the process conditions for fabricating patterns of diffractive optical elements in various shapes were found using direct laser lithographic system, and optical performance evaluation was performed through fabrication.

• Proceedings of the Optical Society of Korea Conference
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• 2001.08a
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• pp.204-205
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• 2001

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.239-245
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• 2000

In this paper, the fundamental properties of diffractive optical element were investigated. Also, this work deals with theoretical approaches for achromatization in DOE's optical system based on thin lens theory. It is found that achromatization could be satisfied by one hybrid lens only, which is composed of a diffractive and a refractive element. In order to have compact optical system, we used the tele-photo type lens composed of a positive and a negative power elements instead of retro-focus lens. From the Gaussian brackets and Seidel aberration theory, the initial design was numerically obtained. The aberration properties of an initial design was aplanat and flat field. In order to correct the chromatic aberrations, refractive and diffractive elements were used on front element. This hybrid lens is also useful for correction of higher order aberrations. Compared to conventional design composed of refractive lenses only, this approach dramatically improved the compactness of the optical system. Finally, residual aberration balancing results in a lens with focal length of 3.89 mm and overall length of 5.19 mm, which has enough performance over an f-number of 4.0. Also, it is expected to fulfill all the requirements of a digital still camera lens. This optical system is superior to the current refractive lens system in the number of elements, weight, and aberration properties. rties.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.136-137
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• 2002

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.200-203
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• 2001

Micromolding methods such as micro-injection molding and micro-compression molding are most suitable for mass production of plastic micro-optics with low cost. In this study, plastic micro-optical components, such as refractive microlenses and diffractive optical elements(DOEs) with various grating patterns, were fabricated using micro-compression molding process. The mold inserts were made by ultrapricision mechanical machining and silicon etching. A micro compression molding system was designed and developed. Polymer powders were used as molded materials. Various defects found during molding were analyzed and the process was optimized experimentally by controlling the governing process parameters such as histories of mold temperature and compression pressure. Mim lenses of hemispherical shape with $250{\mu}m$ diameter were fabricated. The blazed and 4 stepped DOEs with $24{\mu}m$ pitch and $5{\mu}m$ depth were also fabricated. Optical and geometrical properties of plastic molded parts were tested by interferometric technique.