• Journal of the Korean Society of Visualization
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• v.18 no.1
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• pp.38-43
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• 2020

This paper presents a new type of electrowetting driven tandem light deflector for high performance optical application. To steer an incident light, the proposed light deflector deforms the fluid interface using electrowetting actuation. The performance of the light deflector was experimentally verified by using a prototype of the proposed light deflector. Single and tandem light deflectors were separately prepared using microfabrication processes. The optical tests of the deflectors were conducted using a laser light. The proposed tandem light deflector obtained a 45° beam steering angle with a 5.3° deflection angle while a single light deflector was required for a 10.9° deflection angle to obtain the same beam steering angle. The proposed tandem light deflector with high optical capability can be applied to various optical applications from camera modules in mobile smart devices to advanced future optical systems.

• Korean Journal of Optics and Photonics
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• v.15 no.2
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• pp.171-176
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• 2004

A light deflector integrated laser diode(LD) was fabricated and the characteristics of LD and ourput beam deflection as a function of deflector injection current were measured. To integrate the deflector with LD, a passive waveguide was integrated with the LD and a triangular-type light deflector was fabricated on the upper clad of the passive waveguide section. Light deflection from the fabricated light deflector is controlled by the effective refractive index variation induced by carrier injection. To characterize the effect of the deflector injection current, threshold current, slope efficiency, and output beam spectrum were measured as a function of deflector injection current. From these measured data, the increment in the threshold current and the decrement of the slope efficiency were observed. However, the output beam spectrum was not affected by the deflector. The Beam Propagation Method(BPM) was used to simulate the proposed device and the light deflection was measured by the far-field pattern of the output beam as a function of the deflector injection current. In the fabricated deflector integrated LD, the deflection angle of 1.9$^{\circ}$ at the injection current of 15 ㎃ was obtained.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.182-189
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• 2009

The noise from the sunroof can be divided into the low frequency buffeting noise and the high frequency turbulence noise generated when a car runs at the high driving speed. The wind deflector suppresses the buffeting noise generation by accelerating the vortex shedding from the front edge of sunroof opening, and guides the flow direction so that air can pass smoothly over the sunroof opening. To reduce the buffeting noise and the high frequency noise, it is very important to locate a deflector in a proper position depending on the driving speed and the sunroof opening width. The deflector's sectional shape also plays an important role in efficiently reducing the buffeting and high frequency noise. In this paper, we determined the optimum deflector's sectional shape and examined the flow characteristics behind a sunroof deflector through CFD analysis with changing the deflector height, the driving speed and the sunroof opening width. It is found that the deflector needs to be located in the higher location to control the buffeting noise by shedding the higher frequency vortices to accelerating vortices from the sunroof front edge. The deflector may act as a new noise source at the high driving speed, then it is desirable to put the deflector at the proper height to reduce the flow fluctuations and the noise generation. We also made a road test to verify CFD analysis results in this study.

• 한국전산유체공학회:학술대회논문집
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• 2001.10a
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• pp.99-105
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• 2001

Flow computations have been conducted to study the impingement flowfield over the KSR-III flume deflector To validate Euler solver for the jet impingement flowfieid, the jet flow over a double wedge deflector have been calculated and showed reasonable agreement with experimental data. The transient flow behavior of flume over deflector have been investigated and the flume from the rocket nozzle proved to be getting out of the deflector safely and the thermal effect on the base region of rocket was not considerable.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.3
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• pp.17-22
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• 2006

Sunroof is getting widely used in automobiles since it maintains, compare to window, better air circulation as well as less noise while driving in high speed. In this study, we consider an electronic control type spoiler sunroof which slides backward after tilting a rear part of a glass. Installing a wind deflector on the sunroof reduces noise much more effectively. The height of the wind deflector is designed using a boundary theory related to incompressible air layer. The developed wind deflector is investigated experimentally by measuring a wind noise. When the height of the wind deflector is designed by a fixed type, the sunroof maintains a very quiet interior noise over a certain driving speed, nevertheless it produces relatively loud noise in low driving speed.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.159-163
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• 2020

In this study, the flow analyses around according to the existence or non- existence of the trailer's deflector and the shapes were carried out. In the absence of a deflector, the kinetic energy of the turbulence behind the container also generates higher kinetic energy in a wider area than in the presence of a deflector, which adversely affects the vehicle's driving performance. As a trailer's wind deflector-free model has unstable flow rates around the trailer and high kinetic energy of turbulence than a model with a deflector, it can be thought that the increase of fuel economy can be expected by installing a deflector in the trailer. By applying the study result on flow analysis near trailer due to shape of wind deflector, this study is seen to be suitable for the aesthetic convergence.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.1
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• pp.13-19
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• 2016

The flow-excited Helmholtz resonance phenomenon was investigated numerically using Reynolds averaged Navier-Stokes approach. The fundamental cause of the Helmholtz resonance phenomenon is known as shedding of a single discrete vortex from orifice edge that travels during one period of the oscillation. In this study, serrated deflector, which is biomimetic design of the owl's feather, is used to split a single vortex into small vortices. Rectangular deflector and serrated deflector are compared with numerical results of pressure and streamline inside the cavity. Consequently, the serration breaks the shedding period of vortex core and eliminates the resonance. Also, it changes the flow pattern in according to the location of different serration height. By making inflows and outflows occur simultaneously in spanwise direction in the cavity, the period of Helmholtz resonance disappears. Comparing between rectangular deflector and serrated deflector, the serrated deflector can deal with the Helmholtz resonance more effectively.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.8
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• pp.661-668
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• 2016

Oil deflector prevents oil leakage that occurs in thermoelectric power plant at operating lubricant facilities. Vibration of rotating rotor-induced wear of aluminum tooth in existing oil deflector leads to oil leakage as well as life shortening of the tooth. In this study, an advanced oil deflector was developed for shock absorption and prevention of wear by decreasing clearance (from 0.5 mm to 0.2 mm) between rotor and tooth to minimize oil leakage, and by replacing 2 aluminum teeth in outmost of the oil deflector with hi-performance seal made of engineering plastic. The CFD results were compared between advanced vs. existing oil deflector to determine the amount of oil loss. Structural safety was verified through impact analyses according to the three kinds of engineering plastics, considering cost efficiency, and optimal material of hi-performance seal was chosen.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2628-2633
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• 2009

In a double deflector employed microcolumn, the variation of FOV and scan field width was investigated in mode of conversely biased double deflector to eliminate barrel distortion caused by aberration. The relationship between biased voltage of each deflector and electron emission tip voltage was studied for the maximum FOV and scan field width. The limitation and the linearity of zooming current image are also estimated as a function of electron emission tip voltage.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1037-1040
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• 2003

본 논문에서는 microcolumn 을 위한 초소형 전자빔 deflector 의 제작방법과 microcolumn array 에서 deflector 의 외부 패드를 최소화 할 수 있는 새로운 배선방법을 기술하였다. 배선의 통로 및 절연체 역할을 하는 Pyrex glass 의 양쪽에 각각 실리콘 웨이퍼의 양극접합 및 deep reactive ion etching(DRIE)과 금속 전기 도금을 이용하여 다층배선을 하였다. 이 배선방법을 이용하면 microcolumn array 가 수백개가 되더라도 deflector 의 외부 패드는 항상 8개를 유지할 수 있다.