• Title/Summary/Keyword: $J_e$

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Development of Controller for Optimal Beam Scanning in E-Beam Manufacture System (전자빔 가공기에서 최적 빔 주사를 위한 제어기의 개발)

  • Lim S.J.;Lee C.H.;Kang J.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.154-157
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    • 2005

  • The use of electron-beam(E-Beam) manufacture systems provides a means to alleviate optic exposure equipment's problems. We designed an E-beam manufacture system with SEM function. Optimal beam scanning is one of the most important conditions in the performance of E-beam and SEM. The performance of E-beam manufacture system and images of SEM are a close affinity with each other. Developed E-beam manufacture system consist of the controllers of high voltage, scanning, optic and high voltage generator. In this paper, we analyze the condition of steady beam scanning and describe the development of controller fer optimal beam scanning.

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Activation energy standardization of White LED Phosphor (White LED 형광체의 활성화 에너지 정형화)

  • Jang, In-Hyeok;Kim, Su-Kyoung;Han, Ji-Hoon;Lee, Chang-Hoon;Lim, Houng-Woo
    • Journal of Applied Reliability
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    • v.13 no.2
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    • pp.117-127
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    • 2013

  • In this paper, we studied the correlation between the activation energy($E_a$) of the raw materials and the structural characteristics of the White LED PKGs. The samples used in the study were composed of low power LED 3type and high power LED 5type. To calculate the activation energy($E_a$) of the White LED PKGs conducted three conditions of high temperature operation test based on the Arrhenius model. The number of samples used in the experiment is 10, respectively. The $T_j$ of Conditions and target specifics expressed $T_{j1}$, $T_{j2}$, $T_{j3}$. The activation energy ($E_a$) of the samples was calculated based on the value of the actually measured lifetime. We investigated the correlation between the activation energy ($E_a$) of the raw materials and the structural characteristics of the White LED PKGs. As a result, White LED PKGs activation energy($E_a$) value was confirmed that the material properties affected more than the structural characteristics of the LED PKGs and we found that activation energy of each LED Model has difference. Normally, The activation energy of phosphor of YAG type was indicated from 0.21 to 0.25[eV] and Silicate type was indicated from 0.12 to 0.16[eV]. According to the results, we confirmed that the activation energy of phosphor of YAG type is higher more than The activation energy of phosphor of Silicate type.

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Driving Per Nozzle By Various Waveform Depending On Resonance Frequency In Piezoelectric Inkjet Head (잉크젯 헤드의 공진주파수에 따른 구동파형을 이용한 개별노즐 제어)

  • Kim, Y.J.;Park, C.S.;Sim, W.C.;Kang, P.J.;Yoo, Y.S.;Park, J.H.;Joung, J.W.;Oh, Y.S.
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1542-1543
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    • 2007

  • This paper presents the effect of driving waveform for piezoelectric bend mode inkjet printhead with optimized mechanical design. Experimental and theoretical studies on the applied driving waveform versus jetting characteristics were performed. The inkjet head has been designed to maximize the droplet velocity, minimize voltage response of the actuator and optimize the firing frequency to eject ink droplet. The head design was carried out by using mechanical simulation. The printhead has been fabricated with Si(100) and SOI wafers by MEMS process and silicon direct bonding method. To investigate how performance of the piezoelectric ceramic actuator influences on droplet diameter and droplet velocity, the method of stroboscopy was used. Using the water based ink of viscosity of 11.8 cps and surface tension of 0.025N/m, it is possible to eject stable droplets through 64 nozzles average velocity of 4.05 m/s with standard deviation of 0.06 m/s and average diameter of $29.2\;{\mu}m$ with standard variation of $0.5\;{\mu}m$.

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