압전변압기를 이용한 LCD Backlight용 구동회로의 개발

강태구,안형근,한득영 건국대학교 산업기술연구원 1998 건국기술연구논문지 Vol.23 No.-

This paper describes a driving circuit with a multi-layered piezoelectric transformer(MPT) for the LCD backlight of a portable computer. In order to develop the circuit, we measured at first the L, C, R of the MPT concerned. And, using the measured parameters of L,C,R, we designed and implemented circuits such as a voltage-frequency converter, comparator for tracking resonance frequencies varying when the backlight is turned on, power circuit with two MOSFETs, and triggering circuit with flip/flops. We showed the possibility of tracking the resonance frequency of the MPT under the various load conditions.

交流電流 制御方式에 對한 高調波 解析

韓得永,崔圭夏 건국대학교 1984 學術誌 Vol.28 No.2

Static converters with power switching elements have so many advantages as less bulk, fast response, high efficiency and reliability but the harmonics generated by switching operation make worse the power factor and efficiency of the converter-controlled system. Of the several methods to eliminate the harmonics AC current control is the new method that the load current is continuously controlled by the upper and lower limit currents. By this control method the harmonic contents of load current can be greatly reduced and improved the current waveform under the external setting states. In this paper the concept of the switching function is introduced into the current control case and its transfer characteristics are derived and the harmonics of load current are investigated from the digital computation results.

壓電振動子의 等價回路

韓得永 건국대학교 1984 공대학보 Vol.10 No.1

A general equivalent circuit and a lumped circuit near the fundamental resonant frequency of a piezoelectric ceramic disk were discussed. Also, several relationships between the param parameters of the disk ware suggested. Electromechanical comping factor Kt can be calculated from the measured series and perallel resonant frequencies of the disk, and lumped circuit parameters C1, C0, and L1 can be calculated from the Kt and the measured free capacitance of of the disk. The the parameters such as mechanical characteristic impedance Zo, turn ratio N, mechanical quedity factor Om, and material constants cD33, εS33, h33, can be calculated from the radirs r, thicknees 2, density ρ, and the above calculated values of the disk.

절연판이 복합압전진동자의 공진주파수에 미치는 영향

한득영 건국대학교 1990 學術誌 Vol.34 No.2

This paper introduces a technique of changing the resonant frequency and of depressing the spurious modes in the composite piezoelectric vibrator laminated in the order of piezoelectric vibrator/thin insulator/piezoelectric vibrator, whose vibrators have the same sizes and the same properties, respectively. The composite vibrator has shown the characteristics that the fundamental resonant frequency has decreased and spurious nodes lave depressed with increase of the capacitance of the inserted insulator. And the frequency characteristics of the composite vibrator without insulator have been nearly the some as those of each vibrator.

多電極形 壓電變壓器의 電壓比解析

韓得永 건국대학교 부설 산업기술연구소 1984 논문집 Vol.9 No.-

This paper describes the voltage ratios of a new model of piezoelectric ceramic transformer fabricated with two bisected electrode resonators and a thin insulator. In this case of open circuit and resonance, the voltage ratio dependent on the quality factor ?? and the electromechanical coupling factor ?? of resonators, but independent of the thickness and the area of them, and the phase difference between the input voltage and the output voltage is ??. For the high voltage ratio, it is necessary to use the resonators with high ?? and ??.

유기박막에서의 이온주입에 의한 Carbon Cluster의 형성과 그 전기광학적 특성

유영한,한득영 建國大學校 附設 産業技術硏究所 1993 논문집 Vol.18 No.-

It is well-known that electrical and optical properties of organic films can be modified by relatively low ion fluency. In this paper, dielectric organic thin films of quinacridone were fabricated by deposition on the glass and si substrates in the vacuum evaporator under the condition of 2×10? [Torr] and 450[℃]. And their electrical and optical properties were examined before and after nitrogen ion implantation under the various conditions. The resistivities of the quinacridone films have been decreased by 7 orders after N? ion implantation. It was also shown that their resistivities were independent of its substrates and that peaks in the absorption spectrum were disappeared with increasing the ion energy and N? dose quantity. Those properties can be explained by hopping current model in the carbon clusters created on the quinacridone thin film by ion implantation. Those technics may be used in the connection between organic devices for electronics.

Langevin形 壓電變壓器의 特性硏究

韓得永 건국대학교 1984 學術誌 Vol.28 No.2

This paper suggests a new type of piezoelectric transformer fabricated with two disks of high Q piezoelectric ceramic resonator and a thin insulator, And an equivalent circuit considering the mechanical loss of the piezoelectric ceramic resonator is described. Also, voltage ratios, current ratios, input impedances, resonant frequencies and an approximate equivalent circuit of the transformer are discussed.

Nb₂O??를 添加한 Disk Type PZT 壓電 세라믹素子의 音波送波特性

李圭喆,韓得永 울산대학교 1979 연구논문집 Vol.10 No.2

M.P.B.부근의 조성비인 Pb(Zr 0.54 Ti 0.46)O₃에 Nb₂O??를 첨가하여 원판형 압전세라믹 진동소자를 제작하고 공기 중에서 음파의 주파수 특성을 측정하였다. 소자 중, Nb₂O??가 중량비로 2.0% 첨가된 P-5 소자가 11.48[KHz]에서 가장 강한 음파를 발생하였고 Q값이 34.8이었다. 이 조성비의 압전세라믹 소자는 단일 주파수의 음파를 한 방향으로 송파시키는 장치 등에 광범위하게 응용이 될수 있을 것으로 믿어진다. Disc type piezoelectric ceramic vibrators were fabricated with Pb(Zr 0.54 Ti 0.46) O₃and with impurity Nb₂O?? doped in 0.8, 1.0, 1.4 and 2.0 weight percentage respectively and their acoustic wave characteristics were studied in the air. The sample P-4, doped with Nb₂O?? in 2.0 weight percentage and of the radius 0.935[㎝], thickness 0.145[㎝]and electromechanical coupling factor k??=0.415, generated a strong acoustic wave at 11.48[KHz]and showed good frequency selectivity It's Q-value and other characteristics considered enough to enable the sample to be applied successfully in many transmitting devices.

二重 Langevin 振動子의 變壓特性에 관한 硏究

金漢星,任漢錫,韓得永 건국대학교 부설 산업기술연구소 1982 논문집 Vol.7 No.-

This paper suggests a new model of piezoelectric transformer fabricated with steel plates, piezoelectric ceramics, electrodes and thin insulators. And the transformation ratio and the phase difference of several kinds of those transformers were discussed. As a result, the transformation ratio can be increased by series connection of the output ceramic elements or parallel connection of the point ceramic elements. Phase difference between the input voltage and the output voltage was occurred by 90˚ when the transformer had the maximum transformation ratio. These characteristics seem to be applied to develop the high frequency power transformers.

Langevin 振動子의 音波坊舍에 關한 硏究

韓得永 건국대학교 부설 산업기술연구소 1980 논문집 Vol.6 No.-

In this paper, the characteristics of sound radiated from the Langevin vibrator made of piezoelectric ceramics Pb(??) O₃+1.0 weight percentage of La₂O₃ and S-45C steel disks were studied. As a result, it was shown that, in case of the same ceramic vibrator and the same thickness of steel disks, the tighter the coupling pressure is, the higher the frequency of the strongest sound is; and that, in case of the same ceramic vibrator and the same coupling pressure, the thicker the steel disks are, the lower the frequency of the strongest sound is. These characteristics can be applied to the design of the Langevin vibrator for sonic or ultrasonic devices.