• Title/Summary/Keyword: Optics Design

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SNR Analysis for Practical Electro-Optical Camera System

  • Kim Youngsun;Kong Jong-Pil;Heo Haeng-Pal;Park Jong-Euk;Chang Young-Jun
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.633-636
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    • 2005
  • An electro-optical camera system consists of many subsystems such as the optics, the detector, and the electronics and so on. They may create variations in the processed image that were not present original scene. The performance analysis of the electro-optical camera system is a mathematical construct that provides an optimum design through appropriate trade off analysis. The SNR(Signal to Noise Ratio) is one of the most important performance for the electro-optical camera system. The SNR analysis shown in this paper is performed based on the practical high resolution satellite camera design. For the purpose of the practical camera design, the analysis assumes that the defined radiance, which is calculated for the Korean peninsula, reached directly to the telescope entrance. In addition, the actual operation concept such as integration time and the normal operation altitude is assumed. This paper compares the SNR analysis results according to the various camera characteristics such as the optics, the detector, and the camera electronics. In detail, the optical characteristics can be split into the focal length, F#, transmittance, and so on. And the system responsivity, the quantum efficiency, the TDI stages, the quantization noise and the analogue noise can be used for the detector and the camera electronics characteristics. Finally this paper suggests the optimum design to apply the practical electro-optical system.

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The Developement of Secondary Optics Design Method for LED (LED 2차 광학 시스템의 설계법 개발)

  • Jung, Seung-Gyun;Seok, Dae-Il;Shin, Hwa-Young;Lee, Chang-Mo;Kim, Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.6
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    • pp.26-32
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    • 2007
  • Design methods of LED optic system includes point source assumption and imaginary focus approaches. However, these methods make significant error if the position of LED approachs that of optic system. This paper suggests a new design approach that LED is equally divided, light distribution of each division is predicted and confirmed through reverse tracing of light wave, and then each divided segment is separately designed, Using new design method, two kinds of example optic system were designed and light distribution and efficiency of the systems were evaluated.

Design of a Simply Structured High-efficiency Polarization-independent Multilayer Dielectric Grating for Spectral Beam Combining (SBC 시스템 구성을 위한 단순한 구조를 가지는 고효율 무편광 유전체 다층박막 회절격자 설계)

  • Cho, Hyun-Ju;Kim, Gwan-Ha;Kim, Dong Hwan;Lee, Yong-Soo;Kim, Sang-In;Cho, Joonyoung;Kim, Hyun Tae;Kwak, Young-seop
    • Korean Journal of Optics and Photonics
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    • v.31 no.4
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    • pp.169-175
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    • 2020
  • We design a polarization-independent dielectric multilayer thin-film diffraction grating for a spectral-beam-combining (SBC) system with a simple grating structure and low aspect ratio. To maintain the high quality of the SBC beam, we propose a multilayer mirror structure in which the wavefront distortion due to stress accumulation is minimized. Moreover, to prevent light absorption from contamination, an optimized design to minimize the grating thickness was performed. The optimally designed diffraction grating has 99.36% diffraction efficiency for -1st-order polarization-independent light, for incidence at the Littrow angle and 1055-nm wavelength. It is confirmed that the designed diffraction grating has sufficient process margin to secure a polarization-independent diffraction efficiency of 96% or greater.

Study of a Searchlight Lens to Improve Optical Performance and Fabricability (광학 성능 및 제작성 향상을 위한 탐조등 렌즈 연구)

  • Jo, Ye-Ji;Jung, Mee-Suk
    • Korean Journal of Optics and Photonics
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    • v.31 no.2
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    • pp.81-87
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    • 2020
  • This study examines the design technology of searchlight optics featuring narrow beam angles and high luminous intensities. Halogen and xenon lamps, which are conventional searchlight sources, are vulnerable to vibration and shock, and are large and heavy, making them difficult to transport. In addition, the parabolic mirror located at the rear of the searchlight has the disadvantages of poor performance and low light efficiency, due to the assembly error produced during manufacturing. To solve this problem, a 1-kW halogen lamp is replaced by a 150-W high-power COB LED, and a high-efficiency TIR lens is designed to meet the target performance. Afterward, the TIR lens array is proposed to solve the surface error generated during optical injection. After a prototype is manufactured based on the designed optical system, the optical performance is confirmed to be excellent, by comparing it to that of a commercial halogen-lamp searchlight.

Manufacture of an Acousto-Optical Spectrometer for Radio Astronomical Observations (우주전파관측용 음향광학 전파분광기의 제작)

  • 임인성;최재현;오승엽
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.8 no.1
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    • pp.1-12
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    • 1997
  • The acousto-optical spectrometer as a new type backend of the receiver system for radio astronomical observations is manufactured for radio signal analysis. We studied on the effect of Acousto-Optic and Acousto-Optic devices and designed the optics system. We manufactured the optical mount and the CCD detector for deflected beam and interface card. This acousto-optical spectrometer consisted of a laser, optics, acousto-optic deflector, CCD detector and Interface card. This system use He-Ne laser as a light source and use optics to get parallel beam and to focus the deflected beam. Acousto-optic deflector converts IF signal to ultrasonic wave and deflect the laser beam according to the Bragg deflection. The ultra wide band acousto-optic deflector has 1 GHz bandwidth and a total of 2,048 channel Charge Coupled Device for signal detection. In this study, we discuss the theoretical description on the effect of Acousto-optics, the design of the optics, manufacture of optical mount, CCD detector, interface card and we presented the results of experiment. As a result of measurement, we have 1,000 channels bandwidth from CCD channels.

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