• Title/Summary/Keyword: Area source uniformity

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Fabrication of Silicone Resin TIR Linear Lens and Development of 365 nm Wavelength UV LED Light Source (실리콘 수지 TIR 선형 렌즈 제작 및 365 nm 파장대역 UV LED 조사기 광원 개발)

  • Sung, Jun Ho;Yu, Soon Jae;Anil, Kawan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.6
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    • pp.433-436
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    • 2018
  • A total internal reflection (TIR) linear lens of size $190(W){\times}5(D){\times}2.1(H)mm^3$ has a directivity of $25^{\circ}$ and was made of a polydimethysiloxane (PDMS) silicone resin with a refractive index of 1.4 and a transmittance of 93% at 365 nm UV wavelength. A light source with a size of $190{\times}25.5mm^2$ was fabricated by installing a TIR linear lens on a chip on board (COB) type LED module mounted with a $1.1{\times}1.1mm^2$ size UV LED. The optical characteristics of the light source showed a maximum irradiation density of $3,840mW/cm^2$ at a working distance of 5 mm and a high uniformity of 91.6% over a $150{\times}25mm^2$ irradiation area. The thermal characteristics of the light source were measured at a supply current of 500 mA. The saturation temperature was reached after 30 min of operation, and measured to be $95^{\circ}C$.

Nondestructive Characterization of Materials Using Laser-Generated Ultrasound

  • Park, Sang-Woo;Lee, Joon-Hyun
    • International Journal of Reliability and Applications
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    • v.5 no.1
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    • pp.1-13
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    • 2004
  • It is recently well recognized that the technique for the one-sided stress wave velocity measurement in structural materials provides measurement in structural materials provides valuable information on the state of the material such as quality, uniformity, location of cracked or damaged area. This technique is especially effective to measure velocities of longitudinal and Rayleigh waves when access to only one surface of structure is possible. However, one of problems for one-sided stress wave velocity measurement is to get consistent and reliable source for the generation of elastic wave. In this study, the laser based surface elastic wave was used to provide consistent and reliable source for the generation of elastic wave into the materials. The velocities of creeping wave and Rayleigh wave in materials were measured by the one-sided technique using laser based surface elastic wave. These wave velocities were compared with bulk wave velocities such as longitudinal wave and shear wave velocities to certify accuracy of measurement. In addition, the mechanical properties such as poisson's ratio and specific modulus(E/p) were calculated with the velocities of surface elastic waves.

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Vacuum 'brusher' for the alignment treatment of the large area LCD sub strates

  • Yaroshchuk, O.V.;Liu, P.C.;Lee, C.D.;Lee, C.Y.;Kravchuk, R.M.;Dobrovolskyy, A.M.;Protsenko, I.M.;Goncharov, A.A.;Lavrentovich, O.D.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.768-773
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    • 2005
  • We present an overview of our new method of liquid crystal (LC) alignment based on the anisotropic etching of the alignment layers with a directed plasma flux. The method is realized by the use of anode layer source of "race track" geometry generating two "sheets" of accelerated plasma. These sheets are directed obliquely to the treated substrates. The static and dynamic irradiation regimes have been explored. The optimized processing conditions and materials are discussed. The technique yields an excellent uniformity of liquid crystal alignment of planar, tilted and vertical types. It is shown that the new method can be easily adapted for the alignment treatment of large area substrates used in the modern LCD manufacturing process.

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Performance Evaluation of Aprons according to Lead Equivalent and Form Types (방사선 방어용 앞치마의 납당량, 형태에 따른 성능 평가)

  • Kim, Ki-Won;Choi, Sung-Hyun;Kim, Ki-Yeol;Lee, Ik-Pyo;Hwang, Sun-Gwang;Dong, Kyung-Rae
    • Journal of Radiation Industry
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    • v.10 no.4
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    • pp.219-225
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    • 2016
  • The apron is one of the essential protectors to reduce the exposure dose of radiological technologists. This study is to provide a guideline for purchasing the aprons with excellent performance and to help reducing the exposure dose by measuring the shielding ration and uniformity of aprons according to lead equivalent and form types. The shielding ratio of aprons were measured by using radiation generator and dosimeter. Exposure conditions were 81 kVp, 25 mAs, source to image receptor distance (SID) 100 cm and field of view (FOV) $17^{{\prime}{\prime}}{\times}17^{{\prime}{\prime}}$. Exposure areas for front type and around type aprons were divided into 9 areas and for 2 pieces type aprons were divided into 3 areas of top and 4 areas of skirt. The uniformity of aprons were measured by using fluoroscopy and Image J. The 4 regions of interest (ROI) were set into acquired images and measured uniformity by measuring the standard deviation of pixel intensity in ROIs. In continuous shielding ration measurement of aprons according to exposure area, there was not statistical significance (P>0.05). In ANOVA test of aprons, there was statistical significance (P<0.01). In the results of sheilding ratio, although the aprons had equal lead equivalent, there were difference in shielding ratio from 83.59% to 98.15%. In the results of uniformity, the front type aprons with equal lead equivalent indicated the similar uniformity. However, the around type and 2 pieces type apron with equal lead equivalent indicated the different uniformity each other, from 1.8 to 22.2. If the performance evaluation in this study were conducted regularly before and after purchase the aprons, the exposure does to patients and radiological technologists could be reduced.

The electro-magnetic properties of Xe type flat lamp by discharge electrode structure (Xe형 평면광원의 방전 전극 구조 변화에 따른 전자계 특성)

  • Yang, Jong-Kyung;Pack, Kwang-Hyun;Lee, Jong-Chan;Choi, Yong-Sung;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.05b
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    • pp.15-18
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    • 2005
  • As a display becomes large recently, Acquisition of high luminance and Luminance uniformity is becoming difficult in the existing CCFL or EEFL backlight system. So, study for a performance enhancement has enforced. but lamp development of flat type is asked for high luminance and a luminance uniformity security in of LCD and area anger trend ultimately. In this paper, we changed a tip shape of an electrode for production by the most suitable LCD backlight surface light source, and confirmed discharge characteristic along discharge gas pressure and voltage, and confirmed electric field distribution and discharge energy characteristic through a Maxwell 2D simulation. Therefore the discharge firing voltage characteristic showed a low characteristic than a rectangular type and round type in case of electrode which used tip of a triangle type, and displayed a discharge electric current as a same voltage was low.

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Electricla Properties of Xe Plasma Flat Lamp (Xe 플라즈마 평판 램프의 전기적 특성)

  • Choi, Yong-Sung;Cho, Jae-Cheol;Hong, Kyung-Jin;Lee, Woo-Sun;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.12a
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    • pp.35-38
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    • 2006
  • As a display becomes large recently, Acquisition of high luminance and Luminance uniformity is becoming difficult in the existing CCFL or EEFL backlight system. So, study for a performance enhancement has enforced. but lamp development of flat type is asked for high luminance and a luminance uniformity security in of LCD and area anger trend ultimately. In this paper, we changed a tip shape of an electrode for production by the most suitable LCD backlight surface light source, and confirmed discharge characteristic along discharge gas pressure and voltage, and confirmed electric field distribution and discharge energy characteristic through a Maxwell 2D simulation. Therefore the discharge firing voltage characteristic showed a low characteristic than a rectangular type and round type in case of electrode which used tip of a triangle type, and displayed a discharge electric current as a same voltage was low.

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A Study of Lens Design Technique for Proximity Exposure Using a UVA LED (UVA LED를 이용한 근접 노광용 렌즈 설계 기술 연구)

  • Lee, Jeong-Su;Jo, Ye-Ji;Lee, Hyun-Hwa;Kong, Mi-Seon;Kang, Dong-Hwa;Jung, Mee-Suk
    • Korean Journal of Optics and Photonics
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    • v.30 no.4
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    • pp.146-153
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    • 2019
  • The exposure system is a device that transfers a circuit pattern to a desired location. To display patterns on a substrate without deforming the optical characteristics, the characteristics of the optical exposure system are very important. Therefore, to form a microcircuit pattern, a small divergence angle should impinge on the irradiation area. Also, since the light from the source must react uniformly with the photosensitizer, it must have high luminance efficiency and uniformity of illumination. In this paper a parabolic reflector and an aspherical lens were designed to solve the problem of narrow-angle implementation, and it was confirmed by simulation analysis after their arrangement that the beam angle, uniformity, and maximum illuminance satisfied the target performance.

Development of Plasma Confinement by Applying Multi-Polar Magnetic Fields in an Internal Inductively Coupled Plasma System (선형 유도결합 플라즈마 시스템에서 자장에 의한 플라즈마의 Confinement 효과에 관한 연구)

  • Lim, Jong-Hyeuk;Kim, Kyong-Nam;Yeom, Geun-Young
    • Journal of the Korean institute of surface engineering
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    • v.39 no.3
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    • pp.142-146
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    • 2006
  • A novel internal-type linear inductive antenna, which we refer to as a double comb-type antenna, was developed for a large-area plasma source with substrate size of $880\;mm{\times}660\;mm$ ($4^{th}$ generation glass size). In this study, effect of plasma confinement by applying multi-polar magnetic field was investigated. High density plasmas of the order of $3.18{\times}10^{11}\;cm^{-3}$ could be obtained with a pressure of 15 mTorr Ar at an inductive power of 5000 W with good plasma stability. This plasma density is higher than that obtained for the conventional double comb-type antenna, possibly due to the plasma confinement, low rf voltage, resulting in high power transfer efficiency. Also, due to the remarkable reduction in the antenna rf voltage and length, a plasma uniformity of less than 3% could be obtained within a substrate area of $880\;mm{\times}660\;mm$ as rf power increased.

Triode-Type Field Emission Displays with Carbon Nanotube Emitters

  • You, J.H.;Lee, C.G.;Jung, J.E.;Jin, Y.W.;Jo, S.H.;Nam, J.W.;Kim, J.W.;Lee, J.S.;Jang, J.E.;Park, N.S.;Cha, J.C.;Chi, E.J.;Lee, S.J.;Cha, S.N.;Park, Y.J.;Ko, T.Y.;Choi, J.H.;Lee, S.J.;Hwang, S.Y.;Chung, D.S.;Park, S.H.;Kim, J.M.
    • Journal of Information Display
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    • v.2 no.3
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    • pp.48-53
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    • 2001
  • Carbon nanotube emitters, prepared by screen printing, have demonstrated a great potential towards low-cost, largearea field emission displays. Carbon nanotube paste, essential to the screen printing technology, was formulated to exhibit low threshold electric fields as well as an emission uniformity over a large area. Two different types of triode structures, normal gate and undergate, have been investigated, leading us to the optimal structure designing. These carbon nanotube FEDs demonstrated color separation and high brightness over 300 $cd/m^2$ at a video-speed operation of moving images. Our recent developments are discussed in details.

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Fabrication Of Ultraviolet LED Light Source Module Of Current Limiting Diode Circuit By Using Flip Chip Micro Soldering (마이크로솔더링을 이용한 정전류다이오드 회로 자외선 LED 광원모듈 제작)

  • Park, Jong-Min;Yu, Soon Jae;Kawan, Anil
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.4
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    • pp.237-240
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    • 2016
  • The improvement of irradiation intensity and irradiation uniformity is essential for large area and high power UVA light source application. In this study, large number of chips bonded by micro soldering technique were driven by low current, and current limiting diodes were configured to supply constant current to parallel circuits consisting of large number of series strings. The dimension of light source module circuit board was $350{\times}90mm^2$ and 16,650 numbers of 385 nm flip chip LEDs were used with a configuration of 90 parallel and 185 series strings. The space between LEDs in parallel and series strings were maintained at 1.9 mm and 1.0 mm distance, respectively. The size of the flip chip was $750{\times}750{\mu}m^2$ were used with contact pads of $260{\times}669{\mu}m^2$ size, and SAC (96.5 Sn/3.0 Ag/0.5 Cu) solder was used for flip chip bonding. The fabricated light source module with 7.5 m A supply current showed temperature rise of $66^{\circ}C$, whereas irradiation was measured to be $300mW/cm^2$. Inaddition, 0.23% variation of the constant current in each series string was demonstrated.