High-frequency electrodeless discharge device energized by compact RF oscillator operating in class E mode

Claim 1

In combination with an electrodeless discharge device designed to operate with a rated power consumption when energized with predetermined radio frequency energy as generated by a radio-frequency power source, said radio-frequency power source having an output portion comprising a tuned circuit having a resonant frequency which approximates said predetermined radio frequency at which said device is to be operated, said device comprising: a sealed light-transmitting globular-shaped envelope of predetermined dimensions, a discharge-sustaining medium within said envelope, and a layer comprising phosphor material carried on the interior surface of said envelope; a core operatively positioned in energy transferring relationship with respect to said envelope, said core principally comprising magnetic material of high permeability and having a looped configuration of predetermined dimensions and also having predetermined cross-sectional dimensions, and a power winding having a predetermined number of turns wrapped about said core; a pair of power input terminals connecting to said power winding for connection to said radio-frequency power source, said power winding and core comprising a part of said tuned circuit output portion of said radio-frequency power source, and during operation of said device, the radio-frequency energy passed through said power winding creates radio-frequency electromagnetic fields through and about said core and within said envelope to excite said discharge-sustaining medium to emit short wavelength radiations, and said layer comprising phosphor is responsive to said short wavelength radiations to emit visible radiations which pass through said envelope; and an additional feed-back signal winding having a predetermined number of turns wrapped about said core and connecting to a pair of feed-back signal output terminals of said device, the improved radio-frequency Class E oscillator circuit which is adapted to be connected to all of said device terminals for energizing said device, said oscillator circuit comprising: (a) circuit input terminals adapted to be connected to a source of A.C. energizing potential, and circuit power output terminals adapted to be connected to said power input terminals of said device for connection to said device power winding; (b) rectifier means connecting across said circuit input terminals for rectifying the A.C. energy to provide across first and second D.C. output terminals thereof a D.C. potential of predetermined value, said first D.C. output terminal being positive with respect to said second D.C. output terminal; (c) transistor means for providing radio-frequency oscillations and having base, collector and emitter terminals, the base terminals of said transistor means connecting through a resistor of predetermined value to said first D.C. output terminal of said rectifier means and to one of said power output terminals, load-network capacitor means of predetermined value connecting between said first D.C. output terminal of said rectifier means and the collector terminal of said transistor means, load-network inductor means of predetermined value connecting between the collector terminal of said transistor means and the other of said circuit power output terminals, said transistor means having a short collector current fall time; and, (d) tuned circuit capacitor means of predetermined value connected across said circuit power output terminals and forming with said device winding and said device core, as connected thereacross, a tuned circuit having a resonant frequency which establishes the radio frequency at which said device is to be operated; and (e) said oscillator circuit also having a pair of feed-back signal input terminals which are adapted to be connected to said feed-back signal output terminals of said device, one of said circuit feed-back signal input terminals electrically connects to one of said first and said second DC output terminals of said rectifier means, and the other of said circuit feed-back signal input terminals electrically connects to the base terminal of said transistor means through a phase-controlling capacitor so that when said device is connected to said oscillator circuit, there is provided feed-back oscillatory energy for said transistor means.