Phosphor-based FEEL shines efficiently with no mercury

By combining characteristics of fluorescent and cathodoluminescent (CL) lamps into a single emitter, researchers at the Industrial Technology Research Initiative (Chatung, Taiwan), National Chiao Tung University (Hsinchu, Taiwan), and Chung Yuan Christian University (Chung Li, Taiwan) have created a planar light source that uses electrons induced by gas discharge to directly cause a phosphor-coated anode to shine

By combining characteristics of fluorescent and cathodoluminescent (CL) lamps into a single emitter, researchers at the Industrial Technology Research Initiative (Chatung, Taiwan), National Chiao Tung University (Hsinchu, Taiwan), and Chung Yuan Christian University (Chung Li, Taiwan) have created a planar light source that uses electrons induced by gas discharge to directly cause a phosphor-coated anode to shine, eliminating the need for UV light–and thus the toxic mercury required in conventional fluorescent lamps. The device, called a flat electron-emission lamp (FEEL), has so far been made in green-emitting versions up to 4 in. square in size and with an efficiency of 40 lm/W.

Filled with nitrogen to a pressure of about 0.1 torr, a typical FEEL includes a cathode glass, a 10 mm spacer, and a CL-phosphor-coated anode glass; both electrode glasses are coated with fluorine-doped tin oxide. Under a potential of a few thousand volts, the anode glows with a visually uniform intensity. By improving the electron emission of the cathode, optimizing the phosphor, and experimenting with different gases, the researchers hope to boost the efficiency of their planar emitter. Contact Jung-Yu Li at jy_lee@itri.org.tw

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