• Title/Summary/Keyword: lens surface

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A Study on the Improvement of the Shape Accuracy of Plastic Lens by Compensation Program (보정 프로그램을 이용한 Plastic 렌즈 Core의 보정에 관한 연구)

  • Woo, Sun-Hee;Lee, Dong-Joo
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.4
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    • pp.112-118
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    • 2008
  • In order to meet the optical performance in the process of the micro lens manufacturing with plastics, it is important to embody accuracy in shape and surface roughness to the intended design. Since it is difficult to machine exactly the mold core of lens fit to the designed shape, in this paper, a simple program using MATLAB is developed for shape correction of the mold core after first machining it. This program evaluates correction parameters(aspheric coefficients and curvature) and generates aspheric NC data for compensating the core surface in prior machining process. The program provides the way to manufacture plastic injection molding lens with aspheric shape of high precision, and is expected to be effective for correction and to shorten the processing time.

A study on the development of CAD system for the design of lens of the turn signal lamp (자동차 방향지시등 렌즈설계를 우한 CAD 시스템의 개발에 관한 연구)

  • 이재원;이우용
    • Journal of the korean Society of Automotive Engineers
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    • v.15 no.3
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    • pp.89-95
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    • 1993
  • This paper presents the development of CAD system for the design of lens of the Turn Signal Lamp that can model and simulate its optical performance. The system consists of three main modules: skin surface modeling module, inner lens modeling module and optical performance simulation module. Skin surface geometry can be modeled by the input of data file and inner lens can be modeled by the input of only four parameter using its geometric characteristics. Also light distribution pattern, the barometer of optical performance is generated by means of finite ray tracing method. The system display modeled geometry, ray tracing and generated light distribution pattern.

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Changes in Optical and Surface Properties of Contaminated Soft Contact Lenses (표면 오염시 소프트콘택트렌즈의 재질에 따른 가시광선투과도 및 표면 변화)

  • Kim, Jungeun;Jung, Boyoung;Noh, Hyeran
    • Journal of Korean Ophthalmic Optics Society
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    • v.17 no.1
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    • pp.83-89
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    • 2012
  • Purpose: This article was to study the optical and surface properties of soft contact lenses (SCL) exposed to eye make-ups. Methods: Rates of the light transmission of etafilcon A (HEMA based hydrogel lens) and lotrafilcon B (silicone based hydrogel lens) exposed to four different cosmetics over time were investigated. After cleansed with multi-purpose solution (MPS), rates of the light transmission and surface change of lens that were exposed to the cosmetics for 7 consecutive days were analyzed. Results: Visible light transmissions of all lenses exposed to cosmetics decreased to 93.35% (HEMA based hydrogel lens) and 90% (silicone based hydrogel lens) compared with those of the fresh SCLs, such as 97.8% and 96.4%, respectively. It was found that cosmetic residues from powder eye shadow and mascara attached to the lenses were not removed completely when cleansed with MPS. Especially with silicone based hydrogel lens, we found a decrease in visible light transmission of the lens and noticeable particles on lens surface imaged by SEM. Conclusions: Depending on types of eye make-ups and contact lens materials, make-ups were not completely eliminated with current cleansing methods and that caused a decrease in optical property and a change in surface property of the lenses.

Study on the Changes of Ophthalmic Plastic Lens due to Heating (가열에 의한 플라스틱 렌즈의 변화 연구)

  • Cho, Hyun Gug;Moon, Byeong-Yeon
    • Journal of Korean Ophthalmic Optics Society
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    • v.16 no.3
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    • pp.247-253
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    • 2011
  • Purpose: The changes in properties of plastic lens due to heating was investigated. Methods: Plastic lenses of -2.00 diopter were heated at 60-100$^{\circ}C$, and then changes of refractive power, surface condition and transmittance were examined. Results: It was shown that the changes of lens surface due to heating happened at 70$^{\circ}C$ for 1h, 75$^{\circ}C$ for 10 min and 100$^{\circ}C$ 10 sec, respectively. More serious crack was occurred in high index lens and at higher heating temperature, respectively, and transmittance decreased depending on the extent of the damage on the surface of lens. Conclusions: Heating at temperatures above 70$^{\circ}C$ drives cracks on the surface of lens. Optician should recommend an appropriate lens considering the wearer's working conditions and guide for paying attention when they use eyeglasses.

Radiation Dose Reduction of Lens by Adjusting Table Height and Magnification Ratio in 3D Cerebral Angiography (삼차원 뇌혈관조영술에서 테이블 높이와 확대율 조절에 따른 수정체 선량 감소에 대한 연구)

  • Yoon, Jong-Tae;Lee, Ki-Baek
    • Journal of radiological science and technology
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    • v.45 no.4
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    • pp.313-320
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    • 2022
  • Both angiography and interventional procedures accompanied by angiography provide many diagnostic and therapeutic benefits to patients and are rapidly increasing. However, unlike general radiography or computed tomography using the same X-ray, the amount of radiation is quite high, but the dose range can vary considerably for each patient and operator. The high sensitivity of the lens to radiation during cerebral angiography and neurointervention is already well known, and although there are many related studies, it is insufficient to easily reduce radiation in diagnosis and treatment. In this situation, in particular, by adding three-dimensional rotational angiography (3D-RA) to the existing two-dimensional (2D) angiography, it is now possible to make an accurate diagnosis. However, since this 3D-RA acquires images through projection of more radiation than before, the exposure dose of the lens may be higher. Therefore, we tried to analyze whether the radiation dose of the lens can be reduced by moving the lens out of the field range by adjusting the table height and magnification ratio during the examination using 3D-RA. The surface dose was measured using a rando phantom and a radiophotoluminescent glass dosimeter (PLD) and the radiation dose was compared by adjusting the table height and magnification ratio based on the central point. As a result, it was found that the radiation dose of the lens decreased as the table height increased from the central point, that is, as the lens was out of the field of view. In conclusion, in 3D-RA, moving the table position of about 2 cm in height will make a significant contribution to the dose reduction of the lens, and it was confirmed that adjusting the magnification ratio can also reduce the surface dose of the lens.

Precision Surface Profiling of Lens Molds using a Non-contact Displacement Sensor (비접촉 변위센서를 이용한 초소형렌즈 정밀금형 형상측정)

  • Kang, Seung-Hoon;Jang, Dae-Yoon;Lee, Joohyung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.2
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    • pp.69-74
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    • 2020
  • In this study, we proposed a method for surface profiling aspheric lens molds using a precision displacement sensor with a spatial scanning mechanism. The precision displacement sensor is based on the confocal principle using a broadband light source, providing a 10 nm resolution over a 0.3 mm measurable range. The precision of the sensor, depending on surface slope, was evaluated via Allan deviation analysis. We then developed an automatic surface profiling system by measuring the cross-sectional profile of a lens mold. The precision of the sensor at the flat surface was 10 nm at 10 ms averaging time, while 200 ms averaging time was needed for identical precision at the steepest slope at 25 deg. When we compared the measurement result of the lens mold to a commercial surface profiler, we found that the accuracy of the developed system was less than 90 nm (in terms of 3 sigmas of error) between the two results.

The beam property simulation for the fabrication of a MLA(Micro Lens Array) (MLA(Micro Lens Array) 제작을 위한 광학 시뮬레이션)

  • Oh, Hae-Kwan;Seo, Hyun-Woo;Kim, Geun-Young;Wei, Chang-Hyun;Song, Yo-Tak;Lee, Kee-Keun;Yang, Sang-Sik
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1497_1498
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    • 2009
  • This paper presents the simulation of micro-lens arrays based on dry and wet etching technique. Code V (Optical Research Associates Ltd) simulation was performed to extract optimal design parameters of a Micro-Lens Array(MLA). Thickness of UV adhesive, wavelength of laser source, curvature, and shape of lens surface were chosen for the design parameters. The simulation results showed that focal length of a MLA decreased with the increase of UV adhesive thickness. And the focal length depended on shape of lens surface and length of laser source.

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The Characteristics of SIL Lens Machining Using Diamond Turning Machine (초정밀가공기를 이용한 SIL 렌즈의 절삭특성)

  • Won, Jong-Ho;Park, Won-Kyoo;Kim, Ju-Hwan;Kim, Geon-Hee
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.2 no.1
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    • pp.63-68
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    • 2003
  • The aspherical lenses are used as objective lens of optical pickup. To examine the design factor the sample product is made before manufacturing of injection mould of lens. The optimum cutting condition of PMMA lens sample with ultra precision SPDT, the roam spindle speed, the depth of cut, the feedrate are found. The demanded surface roughness 100m Ra, aspherical form error $0.5{\mu}m$ P-V for aspherical lens of optical data storage device are satisfied.

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A Study on the Optical Properties of Contact Lens Analyzer CA-20 (CONTACT LENS ANALYZER CA-20의 광학계 성능 조사)

  • Ji, Taeksang;Lim, Hyeonseon;Kim, Bonghwan
    • Journal of Korean Ophthalmic Optics Society
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    • v.5 no.1
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    • pp.199-203
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    • 2000
  • Magnification shall large to test a surface of a contact lens also chromatic aberration and distortion to be removed. Be used of this study a contact lens analyzer is "CONTACT LENS ANALYZER CA-20", it is a good analyzer to suitable with surface test 16 times of big magnification and distortion.

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