Friday, June 13, 2008

Carbon nanotubes induced high efficiency plasma backlight panel


We fabricated a carbon nanotubes (CNTs) induced plasma backlight panel (CNTs-PBP).

This flat plasma panel has unique properties which are low power consumptions, high luminous efficiency, simple production process and low prime cost. Firstly we used the indium-tin-oxide (ITO) glasses as the substrate of the front and the rear panel. The ITO film is used for the electrodes in the light panel. The phosphor powder which was visible light excited and mixed with the commercial binder (BP-55), then screen printed on the ITO-glass substrates. In this process, we added some CNTs in the phosphor powder. This is the key point about the low breakdown voltage of the plasma generation. After fabricated the panel, we measured the luminance intensity, chromaticity diagram, current and voltage characteristics, emission light spectrum and the Paschen's behavior of the device. Furthermore we optimized the luminance of the device with different methods such as adding a reflection layer behind the rear panel, mixing helium gas into the argon plasma and driven the prototype panel by pulse voltage. In the conclusion, the device has a good luminance 550 cd/m2(nits) and a low power consumption 1.4 W. And we also attempt this approach in a study-commercial 14-inch AC- PBP which fabricated in Chunghwa Picture Tubes, LTD. (CPT) while the presence of the CNTs that increased almost 20% of the luminous efficiency at the commercial
luminance intensity standard (10,000 cd/m2) of the backlight panel.
Author - Hui-Chien Ko


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The unique geometric structure of CNTs can raise the ionization rate in the gas
discharge was obtained by gas breakdown characteristic and the glowing plasma intensity which are shift Paschen’s curve and enhance plasma spectrum. In this way, the CNTs have an advantage of low power consumption in plasma backlight application.

We have successfully demonstrated a CNTs induced plasma backlight panel and the experiment results indicate that the CNTs can enhanced the luminous efficiency on the plasma backlight panel. The Xe-CNTs-PBP produced a uniform emission light without any light diffuser assistant. The luminance of the Xe-CNTs-PBP is 200 cd/m2 while driven by DC power. With the pulse driven circuit the luminance of the Xe-CNTs-PBP increased ~170% to reach luminance 550 cd/m2 with 1.4 W. These results indicate that CNTs have unique properties which are suitable for used in flat light source. The advantage of using CNTs in such application is low power consumptions and good luminous efficiency which provides a better solution for commercial plasma visible light panel.

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