Capillary Plasma Electrode Discharge as an Intense ... - IEEE Xplore

IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 37, NO. 8, AUGUST 2009

1611

Capillary Plasma Electrode Discharge as an Intense and Efficient Source of Vacuum Ultraviolet Radiation for Plasma Display Soo-Ho Park, Tae-Seung Cho, Member, IEEE, Kurt H. Becker, Member, IEEE, and Erich E. Kunhardt, Member, IEEE

Abstract—The characteristic properties of microscale capillary plasma electrode structures were experimentally investigated and compared to the dielectric barrier discharge (DBD) structure. The vacuum ultraviolet (VUV) emission from the capillary plasma electrode discharges (CPEDs) was more intense and more efficient than the one from the DBD. Based on VUV emission characteristics, it is confirmed that the CPED-based plasma display could be a possible candidate to find the breakthrough in the luminance and luminous efficiency of plasma display. Index Terms—Capillary plasma electrode discharge (CPED), light source, microdischarge plasma, vacuum ultraviolet (VUV).

I

N RECENT years, the plasma display panel (PDP) has been one of the most marketable flat displays in the digital TV market, owing to its advantages such as good natural-color reproducibility, thin thickness, wide view angle, large-sized panel, high contrast, and long lifetime [1], [2]. Over the last few years, through the remarkable progress of PDP technology development and manufacturing, many PDP manufacturers compete to bring new products to market having high image quality at low cost [3], [4]. Many researches have made to improve the luminous efficiency of an AC-PDP, but the realization of a high efficient AC-PDP is still a key issue so as to be superior to the quality of LCD-TVs. However, the luminous efficiency of the conventional surface discharge structure with three electrodes remains still insufficient because of the inefficient plasma mode and small discharge volume. The research on new cell structure for innovative luminous efficiency by using different discharge mode is indispensable and has been tried by many researchers [5]–[8]. The capillary plasma electrode discharge (CPED), which was introduced by Kunhardt et al. [9]–[11], is one of several realizations of discharge concepts that generate and sustain high-density stable glow discharges at atmospheric pressure. The basis of the CPED approach is a novel concept to suppress the glow-arc transition instability by stabilizing the cathode fall region of the discharge. In this paper, the CPED concept was applied to the conventional plasma display, and Manuscript received March 25, 2009; revised May 2, 2009. First published June 19, 2009; current version published August 12, 2009. S.-H. Park and T.-S. Cho are with the PDP Development Team, PDP Division, Samsung SDI Company, Ltd., Cheonan 330-300, Korea (e-mail: [email protected]). K. H. Becker and E. E. Kunhardt are with the Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, NJ 07030 USA. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TPS.2009.2025170

Fig. 1. Schematic diagram of the front substrate of conventional DBD-based plasma display and the suggested one employing a CPED.

Fig. 2. Laser microscopic images of the capillaries which were fabricated by a sandblasting method.

its vacuum ultraviolet (VUV) emission characteristics were compared with those of a dielectric-barrier-discharge (DBD)based PDP. Fig. 1 shows the cell structures of the front substrate of conventional DBD-based plasma display and the suggested one employing a CPED. It is essentially a perforated DBD structure. The capillary holes on the front dielectric layer were fabricated by using a sandblast method which is being used for commercial production line in plasma display industry, and other layers were prepared by the same methods as the conventional manufacturing process. Fig. 2 shows the laser microscopic images of the capillaries on the dielectric surface. We fabricated capillaries of three different diameters of 75, 100, and 125 μm on the dielectric layer of 90 μm thick. The depth of the capillaries is 70 μm. After fabricating the hole on the dielectric layer, a magnesium–oxide film was evaporated with the thickness of 0.7 μm. The cell pitch, electrode gap, and electrode width were 1080, 100, and 300 μm, respectively. The thickness of the dielectric layer for the DBD-based structure was 30 μm.

0093-3813/$26.00 © 2009 IEEE

1612


Fig. 3. Experimental setup of the VUV detection system.

Fig. 3 shows a schematic diagram of the experimental setup for measurement of the VUVs from the test sample. A separate discharge chamber, in which we placed the test samples, was attached to a vacuum monochromator. VUV emissions from the test cell entered the vacuum monochromator through a MgF2 window, which limited the detected radiation to wavelengths above about 120 nm. The discharge chamber was evacuated by a first pumping stage to a base pressure of ∼10−6 -torr range and backfilled with 300 torr of penning gas mixture, i.e., Ne + Xe (4.5%). The second pumping stage evacuated the vacuum monochromator to a base pressure of about 1 × 10−6 torr. The vacuum monochromator is a Minuteman 0.2 m Seya-Namioka Instrument with a holographic grating that covers the wavelength range from 50 to 250 nm. The VUV photons are detected by a sealed Hamamatsu model 6836 photomultiplier tube (PMT) through the MgF2 window. The output of the PMT was fed into an Ortec 460 amplifier and an Ortec 584 constant fraction discriminator. For spectral scans, the entire data acquisition and analysis process, including the scanning of the monochromator, was controlled by a PC. For time-resolved measurements, the signals were filtered using a 30-MHz low-pass filter to remove stray noise, and the data were recorded using a Stanford Research Instruments SR400 gated photon counter. Fig. 4 shows the firing and sustain voltages of the DBD and of three capillary structures. The firing and sustain voltages of all capillary structures were lower than those of the DBD structure. The capillary structure with D = 125 μm showed the lowest firing and sustain voltages of 262 and 200 V for a pulsewidth of 2 μs, and 258 and 170 V for a pulsewidth of 6 μs. Thus, from the viewpoint of voltage requirement to ignite and sustain a discharge, the 125-μm capillary structure has the lowest requirements. Fig. 5 shows the VUV spectra from the DBD and the CPEDs with the diameter of 125 μm at 300 and 350 V for the pulsewidths of 2 and 4 μs. The spectra consist of a narrow feature at 147 nm which corresponds to the Xe resonance line and the broad feature whose intensity peaks at 172 nm, which is attributed to the Xe∗2 second excimer continuum. The intensities of both the resonance lines and the excimer emission increase with increasing voltage and also increase with increasing pulsewidth for all structures. By comparison, the overall emission intensities of the CPED are higher than

Fig. 4. Firing and sustain voltages of the DBD and three capillary structures for the pulsewidths of 2 and 4 μs, where Vf is the firing voltage and Vs is the sustain voltage.

Fig. 5. VUV spectra of the DBD cell and CPED cell for various voltages and pulsewidths.

those of the DBD structure. For the purpose of plasma display application, based on VUV spectra, it is obvious that the CPEDbased plasma display structure could be brighter than the DBDbased one because the phosphor is excited by the VUV and emits the visible light for displaying the image. Fig. 6 shows the total amount of the VUV emission from the DBD and the various CPEDs of 75, 100, and 125 μm in capillary diameter for the voltages of 300 and 350 V with the pulsewidths of 2 and 4 μs. The VUV emission increases as the driving voltage and the pulsewidth increase. This characteristic tendency was commonly observed for all capillaries as well as DBD. The variation of total emission from the DBD and the CPED of D = 75 μm was smaller than the other cases. The CPED of D = 125 μm emitted the largest amount of VUV for the 350-V case, while the CPED of D = 75 μm emitted the largest for the 300-V case. At the voltage of 350 V with the pulsewidth of 4 μs, the total emission from D = 125 μm

PARK et al.: CPED AS AN INTENSE AND EFFICIENT SOURCE OF VUV RADIATION FOR PLASMA DISPLAY

1613

perimental results confirm that the CPED-based plasma display could be a possible candidate to find the breakthrough in the luminance and luminous efficiency of plasma display. R EFERENCES

Fig. 6.

Fig. 7.

Total amount of VUV from the DBD and the CPED structures.

VUV emission efficiency for the DBD and the CPED structures.

CPED is 2.1 times larger than that from DBD, where the total emission from D = 75 μm CPED at 300 V with 2 μs is only 1.8 times larger that that from DBD. These characteristic properties say that the capillary works well at the lower voltage for the smaller diameter CPED and also at higher voltage for the bigger diameter CPED. Fig. 7 shows the VUV efficiency which was defined as the ratio of a total VUV emission to power consumption for discharge. The CPED of D = 125 μm has approximately 4 times higher VUV efficiency than the DBD for all cases only, except the 300 V with 2 μs of which the CPED is only 3.1 times higher than the DBD as shown in Fig. 7. For all driving voltage and pulse width, the CPED of D = 125 μm has the highest VUV efficiency than any other CPEDs as well as the DBD. These characteristics confirm that the CPED-based plasma display structure could have higher efficiency than the DBD-based one. In conclusion, the characteristic properties of microscale CPEDs were investigated and compared to the DBD structure. The VUV emission from the CPEDs was more intense and more efficient than the one from the DBD. In addition, the ex-

[1] L. F. Weber, “The promise of plasma display for HDTV,” in Proc. SID, 2000, pp. 402–405. [2] J. P. Boeuf, “Plasma display panels: Physics, recent developments and key issues,” J. Phys. D, Appl. Phys., vol. 36, no. 6, pp. R53–R79, 2003. [3] W. S. Kim, J. W. Shin, S. Y. Chae, B. C. Hyun, and B. H. Cho, “A study of a simple PDP driver architecture using the transformer network,” J. Power Electron., vol. 8, no. 2, pp. 148–155, 2008. [4] S. K. Han and M. J. Youn, “High performance and low cost single switch current-fed energy recovery circuits for AC plasma display panels,” J. Power Electron., vol. 6, no. 3, pp. 253–263, 2006. [5] J. Kang, “Effect of bus electrode position in a high resolution AC plasma display panel with high Xe included gas mixtures,” IEEE Trans. Plasma Sci., vol. 34, no. 2, pp. 371–375, Apr. 2006. [6] K. Tachibana, S. Kawai, H. Asai, N. Kikuchi, and S. Sakamoto, “Characteristics of Ne-Xe microplasma in unit cell of plasma display panel equipped with counter sustain electrodes and auxiliary electrodes,” J. Phys. D, Appl. Phys., vol. 38, no. 11, pp. 1739–1749, Jun. 2005. [7] H. Asai, S. Ajisaka, S. Mori, A. Oku, K. Ikesue, S. Mori, K. Tanaka, N. Kikuchi, M. Hiroshima, and S. Sakamoto, “Development of new structure AC-PDP using thick film ceramic sheet technology,” in Proc. IDW, 2003, pp. 897–900. [8] M. H. Nam, J. M. Kim, S. Y. Choi, S. H. Son, and Y. M. Kim, “Characteristics of plasma display panel with ridged dielectric and hollow gap between sustain electrodes,” J. Appl. Phys., vol. 96, no. 2, p. 993, Jul. 2004. [9] E. E. Kunhardt and K. H. Becker, “Glow plasma discharge device having electrode covered with perforated,” U.S. Patent 5 872 426, Feb. 16, 1999. [10] E. E. Kunhardt and K. H. Becker, “Method for generating and maintaining a glow plasma discharge,” U.S. Patent 6 005 349, Dec. 21, 1999. [11] E. E. Kunhardt, “Generation of large-volume, atmospheric-pressure, nonequilibrium plasmas,” IEEE Trans. Plasma Sci., vol. 28, no. 1, pp. 189– 200, Feb. 2000.

Soo-Ho Park received the B.S. and M.S. degrees from Kwangwoon University, Seoul, Korea, in 1994 and 1998, respectively, and the Ph.D. degree from Stevens Institute of Technology, Hoboken, NJ, in 2004. From 2004 to 2005, he was with PDP TV Development Team, Samsung Electronics Company, Ltd., Korea, as a Senior Engineer. From 2005 to 2008, he was with the R&D Center and PDP Development Team, Samsung SDI Company, Ltd., Cheonan, Korea, as a Senior Engineer, where his research fields were in plasma diagnostics, microplasma applications, dielectric barrier discharge, and plasma display panels. Since 2009, he has been with the R&D center, Samsung SDI Company, Ltd. His current research interests include lithium ion batteries and Smart Window Technology. Dr. Park is a member of the Society of Information Display.

Tae-Seung Cho (M’08) received the B.S., M.S., and Ph.D. degrees from Kwangwoon University, Seoul, Korea, in 1995, 1998, and 2002, respectively. From 2002 to 2003, he was with Stevens Institute of Technology, Hoboken, NJ, as a Research Scholar, where he worked on the applications of dielectric barrier discharge and capillary discharge. From 2003 to 2005, he was a Senior Engineer with Plasmion Corporation, Hoboken, where his research concern was the capillary plasma application for surface modification and flat panel display. Since 2005, he has been with the R&D Center and PDP Development Team, Samsung SDI Company, Ltd., Cheonan, Korea, as a Senior Engineer. His current research fields are in plasma diagnostics, microplasma applications, dielectric barrier discharge, plasma display panels, and LCD backlights. Dr. Cho is a member of the Society of Information Display and the American Physical Society.

1614

Kurt H. Becker (M’03) received the Dipl.Phys. and Dr.rer.nat. degrees from the Universitat des Saarlandes, Saarbrucken, Germany, in 1978 and 1981, respectively. From 1984 to 1988, he was with the faculty of Lehigh University, Bethlehem, PA. From 1988 to 1997, he was with the City College of New York, New York. Since 1997, he has been a Professor and the Director of the Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, NJ. He is also currently the Associate Provost for Research and Technology Initiatives and the Dean of Sciences and Arts, Polytechnic Institute of New York University, New York. His research interests include experimental atomic, molecular, and gas discharge physics, with an emphasis on the study of electron-driven processes in environments, ranging from single-collision experiments to processes in high-pressure discharge plasmas. Dr. Becker is a Fellow of the American Physical Society.


Erich E. Kunhardt (M’78) received the M.S. degree from New York University, New York, in 1972, and the Ph.D. degree in electrophysics from the Polytechnic Institute of New York University, New York, in 1976. From 1976 to 1986, he was with the faculty of Texas Tech University, Lubbock, particularly with the Pulsed Power Laboratory. From 1986 to 1991, he was with the faculty of the Polytechnic Institute of New York University as a Director of the Weber Research Institute. He is currently the George Mead Bond Professor of physics and engineering physics with Stevens Institute of Technology, Hoboken, NJ. His research interests include nonequilibrium electron kinetics in gases and condensed matter, quantum transport in mesoscopic and disordered systems, gaseous and condensed matter electronics, nonlinear optics and dynamics, and computational physics. Dr. Kunhardt is a member of the American Physical Society and the American Association for the Advancement of Science.