• Title/Summary/Keyword: Lens system design

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Research to Minimize Endoscope and Objective-lens Sensitivity Using Multi-configurations (다중 구성을 이용한 내시경 및 대물렌즈 광학계 공차 민감도 최소화 설계 기술)

  • Jung, Mee-Suk
    • Korean Journal of Optics and Photonics
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    • v.32 no.6
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    • pp.259-265
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    • 2021
  • Recently, lens manufacturing and assembly technology has greatly improved. However, tight requirements of manufacturing and assembly lead to an increase in cost and manufacturing time, and in some cases the performance of an optical system may deteriorate depending on the operating environment's conditions, such as temperature or vibration. In addition, the use of a compensator is an effective method to reduce sensitivity in an ultra-precision optical system, but in the case of a small lens, such as that in an endoscope, it is difficult to use a compensator due to the size limitation of the lens barrel. Therefore, minimizing lens sensitivity is the most important technology in lens design. For this reason, there have been various attempts to reduce the lens sensitivity, and there is a trend to add functions to reduce the sensitivity in the lens design S/W. In this paper, we introduce a design technology that minimizes lens sensitivity. We first design a lens with quite good performance, then analyze the sensitivity of this lens, make a multi-configuration with high-sensitivity element error, and then reoptimize it. We prove with an example that this design technique is very effective.

Optical system design for compact digital still camera using diffractive optical elements (회절광학소자를 이용한 컴팩트 디지털 스틸 카메라용 광학계 설계)

  • 박성찬
    • 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.

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A Optical System Design of LED Marine Lanterns Based on a TIR Collimator Lens (전반사 렌즈를 이용한 LED 등명기 광학계 설계)

  • Go, Dong Hyun;Lee, Yoon Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.11
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    • pp.1-5
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    • 2015
  • In this paper, we propose the optical system design for a medium sized LED marine lanterns which simplifies the multi-layer structure into a single structure. In order to satisfy the target fixed intensity(35,000cd) and vertical divergence($-2.5^{\circ}{\sim}-4.0^{\circ}$, $+2.5^{\circ}{\sim}+4.0^{\circ}$), we use the total internal reflection collimator lens. And a Monte Carlo simulation has been utilized to optimize a condition of a LED package, TIR lens and outside lens. The computer simulation results indicated that this LED marine lanterns can produce of a fixed intensity(35,382cd) and vertical divergence($-3.1^{\circ}{\sim}+2.5^{\circ}$). Using the this optical system, we achieve the target value of LED lanterns.

Optics of the light-weight and foldable telescope based on the Fresnel lens

  • Yu, Hyungjoon;Park, Yong-Sun;Chung, Haeun
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.1
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    • pp.57.3-58
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    • 2016
  • We analyze an optical system of a telescope based on Fresnel type objective lens as suggested by Hyde (1999). The Fresnel objective lens can be thin, light-weight and foldable, and therefore it is possible to develop a space telescope with an aperture larger than that of traditional telescopes. Moreover a lens, whatever it is either Fresnel type or conventional, allows much larger fabrication tolerances. We design a medium-sized telescope adopting Fresnel lens as an objective lens for use in space and possibly on the ground. The well-known chromatic aberration of the Fresnel primary lens is corrected by a field lens and another Fresnel lens using Schupmann method. An additional lens is used for forming images. We analyze the chromatic and off-axis aberrations of the proposed system analytically and suggest methods for the minimization of off-axis aberrations and for the operation in wider spectral range. We also conduct ray tracing and optimize the whole optical system with commercial software. Finally we present the design parameters of a telescope with an aperture of 0.5 to 1 meters, enabling diffraction limited operation for a moderate field of view about 10 arc-minutes.

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Wind-lens turbine design for low wind speed

  • Takeyeldein, Mohamed M.;Ishak, I.S.;Lazim, Tholudin M.
    • Wind and Structures
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    • v.35 no.3
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    • pp.147-155
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    • 2022
  • This research proposes a wind-lens turbine design that can startup and operate at a low wind speed (< 5m/s). The performance of the wind-lens turbine was investigated using CFD and wind tunnel testing. The wind-lens turbine consists of a 3-bladed horizontal axis wind turbine with a diameter of 0.6m and a diffuser-shaped shroud that uses the suction side of the thin airfoil SD2030 as a cross-section profile. The performance of the 3-bladed wind-lens turbine was then compared to the two-bladed rotor configuration while keeping the blade geometry the same. The 3-bladed wind-lens turbine successfully startup at 1m/s and produced a torque of 66% higher than the bare turbine, while the two-bladed wind-lens turbine startup at less than 4m/s and produced a torque of 186 % higher than the two-bladed bare turbine at the design point. Findings testify that adding the wind-lens could improve the bare turbine's performance at low wind speed.

Continuous-phase Lens Design via Binary Dielectric Annular Nanoslits

  • Woongbu Na;Seung-Yeol Lee;Hyuntai Kim
    • Current Optics and Photonics
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    • v.7 no.3
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    • pp.304-309
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    • 2023
  • In this study, a binary dielectric annular nanoring lens is proposed to cover the full range of optical phase. The lens is designed numerically, based on the effective-medium theory. The performance of the proposed lens is verified for the cases of single-focal and dual-focal lenses. The efficiency of a single-focal lens is improved by 17.19% compared to a binary dielectric lens, and that of a dual-focal lens shows enhancements of 13.11% and 49.41% at the two focal points. This lens design can be applied to other optical components with axially symmetric structures.

Design of an 8× Four-group Zoom System without a Moving Group by Considering the Overall Length

  • Park, Sung Min;Lee, Jea-Woo;Park, Sung-Chan
    • Current Optics and Photonics
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    • v.6 no.1
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    • pp.104-113
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    • 2022
  • We present a method to count the overall length of the zoom system in an initial design stage. In a zoom-lens design using the concept of the group, it has been very hard to precisely estimate the overall length at all zoom positions through the previous paraxial studies. To solve this difficulty, we introduce Teq as a measure of the total track length in an equivalent zoom system, which can be found from the first order parameters obtained by solving the zoom equations. Among many solutions, the parameters that provide the smallest Teq are selected to construct a compact initial zoom system. Also, to obtain an 8× four-group zoom system without moving groups, tunable polymer lenses (TPLs) have been introduced as a variator and a compensator. The final designed zoom lens has a short overall length of 29.99 mm, even over a wide focal-length range of 4-31 mm, and an f-number of F/3.5 at wide to F/4.5 at tele position, respectively.

Design of a Telecentric Lens with a Smartphone Camera to Utilize Machine Vision (머신비전을 위한 스마트폰용 텔레센트릭 렌즈의 설계)

  • Choi, Yeon-Chan;Rim, Cheon-Seog
    • Korean Journal of Optics and Photonics
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    • v.29 no.4
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    • pp.149-158
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    • 2018
  • A generalized structural design equation can be used to simplify and systematize a telecentric lens system composed of multiple lenses, as a creative design method of the authors. Through this structural equation, we have investigated the feasibility and design methodology of a telecentric lens equipped with a conventional smartphone camera for machine vision. As a result, we could verify and present a useful, generalized structural equation termed the $f{\theta}$ formula, being able to divide and combine the whole telecentric lens system into two modularized lens groups.

Design of micro lens array (Micro lens array 설계)

  • 홍경희
    • Korean Journal of Optics and Photonics
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    • v.5 no.2
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    • pp.204-211
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    • 1994
  • Micro array lens systems are designed for a faximile or copy machine. The array type is hexagonal. Diameter of a lens is 0.16 mm and the distance of the center of the nearest neighbor is 0.192 mm. The magnitude of the lens system is 1:1. Working distane is 10.55 mm and the spot size is less than 0.04 mm radius on axis and 0.20 mm off-axis in case of single layer system. Working distance is 7.90 mm and the spot size is less than 0.07 mm radius on axis and 0.09 mm radius off axis in case of double layer system. Performance of single layer micro array lens system and double layer micro array lens system are compared with the characteristics of the ray fans.y fans.

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Design and Performance of a Catadioptric Omnidirectional Zoom Optical System Using a Hybrid Lens for Visible Light (가시광에서 하이브리드 렌즈를 사용한 반사굴절식 전방위 줌 광학계의 설계 및 성능평가)

  • Park, Hyun Sik;Jo, Jae Heung
    • Korean Journal of Optics and Photonics
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    • v.31 no.2
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    • pp.96-104
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    • 2020
  • A catadioptric omnidirectional zoom optical system using a hybrid lens (COZOSH) that performs simultaneously two functions of a lens and a mirror was designed at the visible wavelength range for daytime unmanned surveillance, and its performance was analyzed. The hybrid lens has lots of advantages in terms of fabrication and assembly of a COZOSH, because of the obviation of a lens boring process and reduction of the number of optical components. Additionally, we designed the COZOSH to expand the compressed inner-image region of a donut image at low spatial frequencies. As a result, the optimized design performance of the optical system that satisfies all initial design specifications was obtained from calculation of the modulation transfer function, spot diagram, and tolerance analysis. We confirmed that the COZOSH is a passively athermalized optical system under conditions of temperature variation from -30℃ to 50℃, by using athermalization analysis during zooming.