• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.162-167
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• 1991

홀로그램 광학소자(holographic optical element)의 일종인 holographic collimating lens(HCL)를 최적 설계하였으며, 중크롬산 젤라틴 필름을 사용하기 최적 설계치에 따라 HCL을 제작하였고 그 성능을 평가하였다. off-axis 방식의 holographic zone plate (HZP) 구조를 채택하였으며, 기록광과 재생광의 파장 차이에 의한 색수차를 최소화시키기 위해 유한 광선 추적법과 감쇠 최소자승법으로 최적 설계하였다. Dipping 법으로 제작된 중크롬산 젤라틴(Dichromated Gelatin, DCG) 필름을 기록 매질로 사용하여 HCL을 제작하였으며 회절광의 집적도를 측정하여 그 성능을 평가하였다.

• Korean Journal of Optics and Photonics
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• v.28 no.2
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• pp.75-82
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• 2017

We present a new type of receiver-transmitter optical system that can be adapted to the sensor head of a displacement-measuring interferometer. The interferometer is utilized to control positioning error and repetition accuracy of a wafer, down to the order of 1 nm, in a semiconductor manufacturing process. Currently, according to the tendency of scale-up of wafers, an interferometer is demanded to measure a wider range of displacement. To solve this technical problem, we suggest a new type of receiver-transmitter optical system consisting of a GRIN lens-Collimating lens-Afocal lens system, compared to conventional receiver-transmitter using a single collimating lens. By adapting this new technological optical structure, we can improve coupling efficiency up to about 100 times that of a single conventional collimating lens.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.132-136
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• 2002

Optical collimating lenses are play a role as maintenance parallel light and as a kind of optical collimating lens, there is Ball lenses, GRIN-rod lenses, spherical lenses and aspherical lenses etc. but recently GRIN lens has monopolized a market. The performance of optical collimator depended on the coupling efficiency. In this paper, we were compared and analyzed to be measured values of coupling efficiency with respect to optical working distance using GRIN rod lenses and spherical lenses. In the case of GRIN lenses with a beam size of 420 ${\mu}{\textrm}{m}$, the minimum coupling efficiency was obtained to a measured value of 0.15 ㏈ and in the case of spherical lenses was obtained to a measured value of 0.12 ㏈ on the same condition. In results, we found that a performance of spherical lenses be better as compared with a that of GRIN lens.

• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.217-221
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• 1992

A micro lens system was designed for the modulator in optical fiber communication. One was the collimating lens which transferred the diffracted beam from optical fiber to the modulator. The other was the coupling lens which connected the modulated collimating beam to the optical fiber. The light source was He-Ne laser beam. The lens would be made of optical glass BK-7. We determined the tolerance of curvature radius, thickness and conic constant.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.6
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• pp.96-101
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• 2020

In this paper, we present the results of our research to perform 3D laser scanning functions by adding a focusing lens to a conventional 2D laser scanner. For the optical design, the ray-tracing technique was used along with a total of four lenses as the variable incident focusing lens, the collimating lens, and the F-Theta lens. As design variables, the curvature of the incident focusing lens (Lens #1) was assumed to be us, l mm and sumed mm, and the incident angles were set at 0cidenus, l. In addition, the distance between the focusing lens and the collimating lens was set to vary from 5 mm to 15 mm. When the incident focal length was varied from 5 mm to 15 mm, the exit focal length was calculated to vary from 67.5 mm to 56.8 mm for the lens with R = 100 mm and from 108.5 mm to 99.0 mm for the lens with R = 150 mm. When the incident angle was 0°, the focal aberration was only slightly observable at 10㎛ in both the x- and y-direction. At 7.5° was the focal aberration of approximately 20~50㎛ was measured at 20㎛. To investigate the chromatic aberration of the designed optical device, the distortion of the focus was observed when the 550 nm beam was simulated on lens designed for a 980 nm wavelength.

• Korean Journal of Optics and Photonics
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• v.9 no.3
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• pp.191-198
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• 1998

A method is described to produce off-axis hologram lenses without astigmatism for semiconductor lasers. We fabricated a holographic collimating lens by using dichromated gelatin film with high diffraction efficiency and without astigmatism which makes a collimated off-axis beam of semiconductor laser. We have designed the holographic collimating lens by applying the classical ray-tracing method to holographic diffraction. The elimination of astigmatism is obtained by choosing appropriate angles of recording and reconstruction beams. The hologram is recorded by use of Ar^{+}$ laser (488nm wavelength) and reconstructed by semiconductor laser(670nm wavelength). The physical parameters of recording and reconstruction angles, wavelength, and astigmatism are analytically calculated and experimentally confirmed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.143-147
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• 2003

Despite of outstanding optical performance of glass lens, glass lens have not been widely used because of poor productivity and high cost due to manufacturing process i.e. grinding, polishing. However, press-forming method of glass lens overcomes this disadvantage because of mass production. When glass lens is produced by press-forming method using closed die, it is needed that the volume of glass lens preform precisely measured in order to prevent incomplete products and to increase in life of die. The present paper shows the shortcoming of forming process with closed die, and performs FEM simulation of forming process with open die in order to overcome this shortcoming. The design parameter of open die is selected in standard of assembly with optical module and maintenance of optical performance. FEM simulation is carried out with selected parameter of open die and two basic preform. According to distribution of effective strain in glass lens, optical property of glass lens formed at each set of die and preform is compared.

• Transactions of Materials Processing
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• v.12 no.4
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• pp.296-301
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• 2003

Though a glass tens has outstanding optical performance, it has not been widely used because manufacturing process shows poor productivity and high cost. However, press-forming method of glass lens overcomes these disadvantages with mass production. When glass lens is produced by press-forming method using closed die, it is needed that the volume of glass lens preform is precisely measured in order to prevent incomplete products and to increase in life of die. The present. paper shows the shortcoming of forming process with closed die, and performs FEM simulation of forming process with open die in order to overcome this shortcoming. The design parameters of open die are selected on the basis of assembly with optical module and maintenance of optical performance. FEM simulation is carried out with selected parameter of open die and two basic preform. According to distribution of effective strain in glass lens, optical property of glass lens formed at each set of die and preform is compared.

• Korean Journal of Optics and Photonics
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• v.32 no.1
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• pp.15-21
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• 2021

In this paper, an aircraft warning light's optical system was designed using an LED light-source module and a collimating Fresnel lens. As for the optical system, a collimator Fresnel lens was designed for each module to satisfy a vertical-elevation center luminous intensity of 20,000 cd and the divergence-angle luminous-intensity standard conditions of the Ministry of Land for Infrastructure and Transport for aircraft warning lights. In addition, the optical system was optimized by adjusting the position and tilt of the LED light-source module and Fresnel lens. By analyzing and comparing the light-distribution characteristics of the optical system, an aircraft-warning-light optical system with optimal performance was obtained.

• Publications of The Korean Astronomical Society
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• v.27 no.3
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• pp.87-93
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• 2012

A low-dispersion fiber feed Littrow-mounted grating spectrometer for education was designed and fabricated. The dispersion element is a reflective type blazed grating Edmundoptics NT 46-075 (spatial frequency 600 lines/mm, dimension $30mm{\times}30mm$, blazed angle 8.6 degree). The optical fiber coupler module for optical guiding from telescope to spectrometer is composed of a multi-mode FC connector - FC connector optical fiber patch cord (core/cladding diameter $50{\mu}m/125{\mu}m$) and two 1.25" throw-tube couplers. The lens for collimating and imaging is a general purpose focal length 50 mm camera lens (f/1.8). The device for optical path control is a rectangular prism (size $25mm{\times}25mm$). The imaging camera sensor is a Meade DSI Pro 2 CCD sensor (black and white, $752{\times}582$ pixels and pixel size $8.3{\mu}m{\times}8.6{\mu}m$). Softwares for data logging and analysis consist of Meade Autostar Suite, NIH imagej and Vernier Logger Pro 3. The wavelength coverage range of the spectrometer is 205 nm at central wavelength 550 nm. The wavelength resolution is 1.7 nm.