• Korean Journal of Optics and Photonics
• /
• v.24 no.5
• /
• pp.213-216
• /
• 2013

This paper presents a combination of linear Fresnel lenses optimized for ${\times}25$ solar concentration. The combined lens consists of $5{\times}5$ linear Fresnel lenses. Each Fresnel lens is of $10{\times}10$ mm and optimized to tilt the incoming light onto a solar cell of the same size. All of the optimized Fresnel segments have the same pattern height of 35 ${\mu}m$, draft angle of $4^{\circ}$, and edge groove round of 1 ${\mu}m$ but with different facet angles varying from $14.1^{\circ}$ to $31.2^{\circ}$. The solar concentrating efficiency of the combination is shown to be over 80% and more robust than a conventional single ${\times}25$ circular Fresnel lens in terms of pointing misalignment and manufacturing errors. A sensitivity analysis finds that the edge groove round should be kept as small as machining allows since the concentrating efficiency drops ~5% per 1 ${\mu}m$ increase of the edge groove.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.05a
• /
• pp.53-54
• /
• 2014

By using geometrical structure of Fresnel lens, it can be applied with receiver antenna and geodetic system. In this paper, radiation pattern from fresnel lens array of Soret type is calculate by the FDTD method. For simplicity, fresnel lens should be located linearly and considered to be dielectric rod with a relative permittivity.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.53-56
• /
• 2009

반사와 굴절이 합쳐진 새로운 형태의 하이브리드 태양광 집광 장치로 기존 집광 장치에 비해 초점 거리가 짧게 설계되었다. 프레넬 렌즈 형태의 굴절부와 프레넬형의 다수의 포물선 반사경이 공통으로 후면 초점(rear focus)을 가지도록 배치하여 기존 프레넬 렌즈만으로 구성된 것보다 선형 집광의 경우는 3배, 점 집광의 경우는 10배 이상 집광비를 높일 수 있다.아울려 이를 이용한 선형 집광형 발전 시스템과 점형 집광 장치는 나름대로 장점을 가진다.

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

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.5
• /
• pp.1-6
• /
• 2008

LCD multimedia system is necessary to display and transfer the effective image informations. However, this system uses several LCD screens, so the problem of gap between the LCD screens occurs. In order to solve this problem, this paper presents a method of using binary Fresnel lens. This kind of binary fresnel lens makes each screen enlarge and minimize the gap. The optimization of design parameters of binary Fresnel lens is presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.05a
• /
• pp.43-44
• /
• 2014

By using geometrical structure of Fresnel lens, it can be applied with receiver antenna and geodetic system. In this paper, we consider Soret typed fresnel lens with reflected plate and its focusing gain characteristics is calculated by the FDTD method.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.1
• /
• pp.63-67
• /
• 2015

White light-emitting diode (WLED) is growing interest in using both illumination and communications. This paper reports visible light communication (VLC) composed of a super bright white light-emitting diode, low cost commercial photo-diode and a Fresnel lens. LED driver is consisted of the power MOSFET and MOSFET driver that switches the LED on and off. The modulation bandwidth of the LED used was determined to be 8 MHz. However, it was possible to communicate up to 1 Mbps under illumination of 500 lx because of the weak signal power and a low spectral sensitivity of the SHF213 as a PIN photodiode. In order to enhance the system bandwidth, the LED light was focused on the PIN photodiode by use of the Fresnel lens. As a result of that, visible light link was operated up to modulation bandwidth of the LED. The signal to noise ratio can be improved by 40 dB using an optical concentration at the receiver.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.05a
• /
• pp.67-69
• /
• 2012

In this paper, electromagnetic scattering analysis of Fresnel Lens by using 2D FDTD method was performed. Fresnel lens which is consigured 7 diffracted conductors, and considered at 5GHz. As a result, axial gain characteristic corresponding to near design focusing distance at 0.71m is 26dB.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.2
• /
• pp.1-7
• /
• 2006

A light guided plate coupled with the micro Fresnel lens array(MFTA) is designed to improve the efficiency of the LCD backlight unit. Blazed Frenel lens and binary multi-level Fresnel lens are adapted for the MFLA. This type of MFLA can replace the prism sheet and diffuser sheet which are used for the conventional type of the LCD backlight unit. The luminance and uniformity are calculated to verify the performance of the MFLA type LCD backlight unit.

• Korean Journal of Optics and Photonics
• /
• v.20 no.1
• /
• pp.1-5
• /
• 2009

Recently, much research has been done for to realizeing nano-scale photonic circuits based on photonic crystal, plasmonics and silicon photonics in order to overcome fundamental limits of electronic circuits. These limits include such as bottleneck of speed, and size that cannot be reduced. Even though several kinds of coupling schemes have been reported, coupling structures are still large when it is compared with the nano-scale optical circuit. In this paper, we proposed using a very thin Fresnel lens while shortening the focal length of the Fresnel lens as much as possible. We proposed, for the first time, to utilize metal slits that are able to use the optical coupling system between a nano-scale optical circuit and the standard single mode optical fiber for overcoming the limitation of focal length shortening of the Fresnel lens. Comparative study has been carried out with a FDTD simulation between normal and metal slit assisted Fresnel lens. From the result of simulation, we can achieve 65% coupling efficiency for the metal-slit Fresnel lens when the focal length of metal-slit Fresnel lens is just $4{\mu}m$. On the other hand, the coupling efficiency of the normal Fresnel lens is about 43%.