• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.283-290
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• 2016

This study presents an 8x four-group inner-focus zoom lens with one-moving group for a compact camera by use of a focus tunable lens (FTL). In the initial design stage, we obtained the powers of lens groups by paraxial design based on thin lens theory, and then set up the zoom system composed of four lens modules. Instead of numerically analytic analysis for the zoom locus, we suggest simple analysis for that using lens modules optimized. After replacing four groups with equivalent thick lens modules, the power of the fourth group, which includes a focus tunable lens, is designed to be changed to fix the image plane at all positions. From this design process, we can realize an 8x four-group zoom system having one moving group by employing a focus tunable lens. The final designed zoom lens has focal lengths of 4 mm to 32 mm and apertures of F/3.5 to F/4.5 at wide and tele positions, respectively.

• Journal of the Optical Society of Korea
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• v.17 no.6
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• pp.518-524
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• 2013

This study presents a new design method for a zoom lens, in which real lens groups are designed successively to combine to form a lens modules zoom system. The lens modules and aberrations are applied to the initial design for a four-group inner-focus zoom system. An initial design with a focal length range of 4.2 to 39.9 mm is derived by assigning the first-order quantities and third-order aberrations to each module along with the constraints required for optimum solutions. After obtaining the lens module zoom system, the real lens groups are successively, not separately, designed to get a zoom lens system. Compared to the separately designed real lens groups, this approach can give a better starting zoom lens and save time. The successively designed groups result in a zoom system that satisfies the basic properties of the zoom system consisting of the original lens modules. In order to have a slim system, we directly inserted the right-angle prism in front of the first group. This configuration resulted in a compact zoom system with a depth of 12 mm. The finally designed zoom lens has an f-number of 3.5 to 4.5 and is expected to fulfill the requirements for a mobile zoom camera having high zoom ratio of 10x.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.494-498
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• 2005

In order to design the aspherical lens, the revisions and the steps of the mathematical method are influenced with a lot of variables. The accuracy of the aspherical lens can be changed by these variables. Besides, to design the aspherical lens, many mathematical functions should be used. To use these mathematical functions is protected by patent administration. Therefore it is very difficult for most of developed countries to use them. This fact has been interrupting not only the development of the technique of a design of the aspherical lens but also the development of the equipments of optics. Because approximate values are used in most of common programs which create the aspherical lens : basically these common programs have variations. Therefore these aspherical lens are not accurate. In the paper, we calculated accurate values by using the refractive index of lens. Based on these data, wee created self-operating design programs. Consequently, our lens is more accurate than the aspherical lens which is created by the common programs influenced with approximate values. The used programs belonging to AutoCAD is Visual LISP.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.10 s.175
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• pp.144-149
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• 2005

This study presents the method of extracting shape design data on any aspheric lens by reverse engineering. The design formula fur aspheric lenses is needed in almost all of the design, manufacture and measuring processes. The difficulty in designing the lens lies in the fact that it uses a complex formula for the aspheric surface, and many of the preliminary design values must be selected before actually inserting them into the formula. If the values could be extracted from an aspheric lens for which the structural design information is unknown and used in designing other lenses of similar characteristics, the difficulties in designing and measuring aspheric lens could be reduced. Therefore, in this study, the concept of reverse engineering was applied to demonstrate the method of extracting shape design information of aspheric lens from an arbitrary aspheric lens.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.3
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• pp.3-8
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• 2007

This study is for aspheric lens that is one of a core technology in the optical industry. The feature of a aspheric lens is not to have the spheric aberration. So in optical industry, aspheric lens are essential element to miniaturization, high effectiveness and light weight. In this study we applied a lay back-tracer method using the index of refraction to design aspheric lens. We developed the automatic design program for aspheric lens by user interfacing program VisualLISP in AutoCAD. And we manufactured aspheric lens and measured it.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.115-118
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• 2002

The purpose of this paper is to design a pick-up for the small form factor optical disk drive and to fabricate a micro-compensatory lens for the pick-up using the micro-compression molding process. At design stage, the optical elements including the objective lens and the compensatory lens are miniaturized. The height of pick-up and free working distance are designed as 2mm and 0.2% respectively. To analyze the fabricated micro-compensatory lens, the system was analyzed using the surface profile of the fabricated micro-compensatory lens and CODE V which is commercial software. The RMS wave front aberration of the system using fabricated micro-compensatory lens is 0.01677λ which is lower than Marechal's criterion, 0.07λ.

• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.13-19
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• 2013

Ftheta Lens, whose image height is proportional to its field view angle, is one of the most important parts in Laser Scanning Unit(LSU). In this paper $f{\theta}$ lens design, mold production and modification method of lens design and mold are introduced. Lens design was carried out with Zemax and Special Toric surfaces were applied for lens surfaces to minimize distortion both in main and sub scanning directions. And a high precision machine with 1nm resolution was used to fabricate lens mold cores. After injection the lens was evaluated and the difference from design was examined. This difference was compensated by modifying lens design and new lens mold cores were made according to modified lens design to obtain the quality of original design.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.4
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• pp.355-360
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• 2010

Purpose: Analysis performance for spectacle lens which sales in domestic market and optimization design a spectacle lens which is corrected aberration. Methods: Measured center thickness, radius and aspherical surface coefficient for spherical and aspherical lenses which were ${\pm}$5.00D. Refractive index for every lens was 1.6 and they came from 4 different companies. I used 3 types of equipment to measure lenses. ID-F150 (Mitutoyo) : Center Thickness, FOCOVISION (SR-2, Automation Robotics) : Radius, PGI 1240S (Taylor Hobson) : Aspherical surface coefficient. Designed a lens which had 27 mm of distance from lens rear surface to center of eye, 4 mm of pupil diameter and small aberration on center vision $30^{\circ}C$. To shorten axial distance compared with the measured lens rise merits for cosmetic. Lens Design tool was CODE V (Optical Research Associates). Results: -5.00D aspherical lens had somewhat high astigmatism and distortion compared with the spherical lens. But it had a merit for cosmetic because of short axial height and decrease edge thickness. Improved a performance of distortion and ascertain merits for cosmetic due to short axial height and decrease edge thickness same as (-) lens in case of +5.00 aspherical lens. Though an optimization process front surface aspherical lens had a good performance for astigmatism and distortion and the merit for beauty compared with measured spherical lens. Conclusions: Design trend for domestic aspherical lens is decrease axial height and thickness to increase a merit for cosmetic not but increase performance of aberration. From design theory for optimization design front surface aspherical spectacle lens which has improved performance of aberration and merit for cosmetic at the same time compared with the measured lens. Expect an improved performance from design back aspherical lens compared with front aspherical lens.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.197-202
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• 2005

An aspheric lens is one of a key point optical element in the optical industry. The feature of an aspheric lens is not to have the spherical aberration. An aspheric lens is also essential element for high-precision and light-weight in the optical machine. Generally it have been used in a tailor progression an aspheric lens modelling much. In this study we applied a lay back-tracer using a index of refraction to draw a creative aspheric lens. Also we developed the automatic design program for aspheric lens. We manufactured the aspheric lens and executed a comparison experiment for refraction situation of shape and straightness experiment to inspect the drawn aspheric lens in this study.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.52-55
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• 2002

In this research, the modification method of spherical aberration, and aspherical lens shape design method were investigated. Spherical aberration affects lens's performance directly. Many studies have attempted to remove spherical aberration with a lot of methods in order to reduce the bad effect of spherical aberration. The approach to lens shape design was base on the ray tracing method. From the result, it was confirmed that ray reverse-tracing method was convenient to remove spherical aberration, and could be used very effectively and usefully for aberration-free aspherical lens design.