Electrodeless discharge lamp including impedance matching and filter network
First Claim
Patent Images
1. An electrodeless discharge lamp comprising:
- a radio frequency generator;
an amplifier connected to an output of said radio frequency generator;
a coil network comprising an induction coil; and
an impedance matching network connected between said amplifier and said coil network, said impedance matching and filter network for providing two preselected impedance transformations for said coil network at different operating conditions of said lamp.
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Abstract
An impedance matching and filter network is disclosed. The network performs two preselected impedance transformations and provides a filtering function to attenuate harmonics of an electrical signal delivered at an input of the network. The network may advantageously be structured in the form of balanced dual filters which are referenced to a virtual ground between them, the virtual ground being connected to a shield which surrounds the electric components. The network is particularly suitable for use with electrodeless discharge lamps to provide an impedance matching function for the induction coil and to limit RFI.
144 Citations
48 Claims
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1. An electrodeless discharge lamp comprising:
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a radio frequency generator; an amplifier connected to an output of said radio frequency generator; a coil network comprising an induction coil; and an impedance matching network connected between said amplifier and said coil network, said impedance matching and filter network for providing two preselected impedance transformations for said coil network at different operating conditions of said lamp. - View Dependent Claims (2, 3, 21, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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4. An electrodeless discharge lamp comprising:
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an oscillator; an amplifier connected to an output of said oscillator; and an induction coil network, said induction coil network comprising an induction coil and a vessel containing a selected gas, said induction coil being operative to create a plasma of charged particles in said gas after said lamp has been turned on; wherein said induction coil network has a first inherent impedance measured at a pair of input terminals of said network when said lamp is initially turned on and a second inherent impedance at said input terminals when said lamp is in a steady-state on condition; and said lamp comprising in addition an impedance matching network connected to said induction coil network, said impedance matching network having a pair of input terminals, said impedance matching network operative to transform said first inherent impedance to a first desired impedance measured at its input terminals when said lamp is initially turned on, and to transform said second inherent impedance to a second desired impedance measured at its input terminals when said lamp is in a steady-state on condition. - View Dependent Claims (5, 6)
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7. An electrodeless discharge lamp comprising:
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a radio frequency amplifier having two output terminals; an induction coil network having two input terminals; and a first filter and a second filter, said first filter being connected between a first output terminal of said amplifier and a first input of said induction coil network, said second filter being connected between a second output terminal of said amplifier and a second input of said induction coil network, said first and second filters being joined together at a common node. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 25)
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19. An electrodeless discharge lamp comprising:
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a power supply; a radio frequency oscillator; an amplifier; an induction coil for transmitting a radio frequency signal delivered by said amplifier so as to create a plasma of charged particles in a gas; a first filter connected between said amplifier and said induction coil so as to inhibit the passage of radio frequency interference (RFI) to said induction coil; and a second filter connected between said power supply and a power main contact of said lamp so as to inhibit the passage of a noise signal to said power main contact.
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20. An electrodeless discharge lamp comprising:
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a metal chassis, said metal chassis enclosing a source of a radio frequency signal and an amplifier for amplifying said signal; and an induction coil positioned outside of said metal chassis, said metal chassis and the center of said coil being maintained at a virtual ground. - View Dependent Claims (26, 27, 28, 29, 30)
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- 22. A discharge lamp containing a power supply, an oscillator and an amplifier, said amplifier being for generating an electrical signal having a frequency of at least 20 KHz, said discharge lamp further containing a line filter connected between said power supply and a power main contact of said lamp so as to inhibit the passage of a noise signal to said power main contact.
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24. An electrodeless discharge lamp comprising:
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a radio frequency generator; an amplifier connected to an output of said radio frequency generator; an induction coil having only two terminals; and a filter network connected between said amplifier and said induction coil, said filter network being configured such that the voltages at the two terminals of the induction coil are of equal magnitude and opposite phase when said lamp is operative.
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- 31. An electrodeless discharge lamp comprising an oscillator, an amplifier connected to an output of said oscillator, an induction coil network comprising an induction coil and a vessel containing a selected gas, and a pair of balanced filters connected between said amplifier and said induction coil network, wherein said amplifier and said oscillator are enclosed within and insulated from a metal chassis and wherein a common node between said pair of balanced filters is connected to said metal chassis.
Specification