• Korean Journal of Optics and Photonics
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• v.7 no.3
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• pp.191-195
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• 1996

A optical system of a movile LIDAR is designed for air pollution research. After the inverse Cassegrain type collimator, the laser beam falls on the mirror which serve for coinciding optical axis of laser beam and the receiving telescope. Then, it is directed into the atmosphere and back scattered radiation back to the receiving telescope by the scanning mirror. The unit of scanning mirror allows to rotate the mirror along the altitude 0$^{\circ}$~60$^{\circ}$, and the azimuth 0$^{\circ}$~360$^{\circ}$. The scanning mirror is not connected with the receiving telescope but placed on the roof of the mobile. The received beam is spatial filtered by a spatial filter and collimated by a fabric lens. Thereafter, the beam is devided into 2 channel for registration by a beam splitter. Each laser beam is transformed into an electrical signal by means of the photomultifier and then processed to be analyzed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1394-1402
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• 2011

This paper describes solar light collecting system which employs parabolic reflector and Fresnel lens and its industrial application. We have introduced second-stage optical system so that it makes optical fiber overcome its numerical aperture limitation and also it makes focused light become collimated, which results in decreased light energy density. As result of these, light collecting efficiency become maximized and the system does not require separate cooling apparatus any more. The developed solar lighting system together with artificial light source like LED has been applied to plant factory as a hybrid lighting source. This makes us save electric energy for artificial lighting during day time. The intensity of LED light in the hybrid lighting system is controlled automatically according to ambient-light-sensor installed in the system so that the light intensity for a plant always keeps the same level no matter how the sun light changes. For a plant factory whose size is 330 square meters, when solar lighting system is applied, 28,080KWh electric energy can be saved per month.2 times.

• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.233-240
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• 2018

In this paper, a design method to reduce fabrication errors in reflector shape of a test lamp for a flame detector is carried out. Although the test lamp should be operated in parallel with a high-intensity light, it is difficult to fix the small reflector that controls the central light during fabrication. To solve these problems, a small spherical reflector is designed to minimize the performance degradation for a light loss factor of less than 5%, even during tilt and decenter, and a spherical shape is proposed for a small reflector with little effect on the error when designing the optical system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.897-900
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• 2002

The collimation mirror will be used for thermal vacuum testing of spacecraft. The reflection mirror system to generate parallel beam inside the thermal vacuum chamber. A 600mm diameter aspheric Collimation mirror was fabricated by ultra-precision single point diamond turning (SPDT). Aluminum alloy for mirror substrates is known to be easily machining, but not polishable due to its ductility. Aspheric large collimation reflector without a conventional polishing process, the surface roughness of 10nmRa, and the from error of $\lambda/2 ~\lambda/4(\lambda$ =632.8 nm) for reference curved surface 600 mm has been required. The purpose of this research is to find the optimum machining conditions for reflector cutting of A16061-T651 and apply the SPDT technique to the manufacturing of ultra precision optical components of metal aspheric reflector.

• Korean Journal of Optics and Photonics
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• v.19 no.4
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• pp.327-333
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• 2008

In general, a lens with large NA makes image quality better. There are many kinds of cheap concave mirrors with large aperture and NA. This paper presents a method that uses a large aperture projection imaging system to enhance the image used for 3D shape measurement. This method makes it possible to enhance reflection uniformity on the object surface and increases SNR (Signal to Noise Ratio). Using a large aperture lens, it is possible to obtain a brighter image, reducing the shading nature in the image boundary, and enhancing the reflection uniformity even on woven surfaces. Because of the exorbitant cost of a large aperture projection lens larger than 150 mm in diameter, a refractive lens was exchanged with a concave mirror resulting in the same optical effect. In experiment, changing NA $0.15{\sim}0.8$, image contrast was enhanced from 46 to 1.33. Incidentally, the effect of the concave mirror was tested successfully through the experiment.