A new deep-UV source has been developed which is a microhollow cathode discharge formed in cathode cavities with dimension on the order of 100 micrometers. The hollow-cathode lamp has numerous advantages over other light sources, including operation at relatively low-voltages in a quiescent DC mode, linear control of the intensity by controlling the current, scalability to large areas in a planar geometry, and a radiant emittance exceeding that of commercially available excimer lamps by more than an order of magnitude. In order to explore the feasibility of converting the basic research result on microhollow cathode discharges into flat panel excimer lamp, plasma deposition techniques will be explored as an economical and scaleable manufacturing method by Prof. Heberlein at the University of Minnesota. Array formation methods, based on forced abnormal glow discharge operation, will be studied by Prof. Schoenbach, Norfolk Applied Science, Inc. and Old Dominion University. The combination of the two techniques, plasma deposition and array formation without individual ballast, promises to lead to the development of a low cost, high radiant emittance, long lifetime, large area flat panel excimer lamp, which covers a wavelength range from 84 nm to 308 nm. Applications of these novel DC excimer lamps are in UV polymerization, photolithography, photo-chemistry, photo-deposition, photo-annealing, pollution control, and lighting. Applications for excimer lamps range from UV polymerization, photolithography, photo-chemistry, photo-deposition, photo-annealing, pollution control, to lighting. Presently the largest market is UV curing. The average growth in this industry has been 10%/year during the last decade. The use of formulated UV (and electron-beam) curable products just in North America is 110 million pounds. Companies involved in UV curing are 3M, DuPont, First Chemical, BASF, amongst others. The highest ranked enabler for growth in this area is "faster cure rates". This requires an increase in the effectiveness and performance of equipment. Considering that the proposed microhollow cathode discharge lamp promises to have an order of magnitude increased power density compared to conventional excimer lamps, the curing industry, a billion dollar industry, would benefit dramatically from the introduction of such a lamp. The cost of a microhollow cathode discharge lamp would be, because of its simplicity and low voltage operation, far less than that of a commercial barrier discharge excimer lamp. By using the same concept as for high power devices, but operate them in a pulsed mode, using simple semiconductor based pulse generators, the illumination can be reduced to any desired level. Applications for low intensity excimer lamps, which do not need to be cooled, are bacterial decontamination and backlighting.
Keywords: High-Power, Flat Panel Excimer Lamps; Microhollow Cathode Discharges
