Claims
- 1. An inductively coupled electrodeless lamp, comprising:
an excitation coil; a capacitor structure connected to the excitation coil, the capacitor structure and excitation coil together forming a resonant lamp circuit; an electrodeless lamp bulb positioned proximate to the excitation coil, the bulb containing a fill which emits light when excited by RF energy; and an RF source connected to the resonant lamp circuit and adapted to provide RF energy for exciting the fill, wherein the capacitor structure is adapted to inhibit arcing during operation of the lamp.
- 2. The lamp as recited in claim 1, wherein the excitation coil comprises a wedding ring shaped excitation coil having an axial lead on one end and a radial lead on the other end,
and wherein the capacitor structure comprises a capacitor stack connected to the axial lead of the wedding ring coil.
- 3. The lamp as recited in claim 2, wherein the capacitor stack comprises a material having a low dielectric constant for the high voltage capacitor.
- 4. The lamp as recited in claim 2, wherein the capacitor stack comprises a conformal coating covering at least a portion thereof.
- 5. The lamp as recited in claim 4, wherein the conformal coating covers substantially all of the capacitor stack and a portion of the axial lead of the wedding ring coil.
- 6. The lamp as recited in claim 2, wherein the capacitor stack comprises a circular high voltage plate.
- 7. The lamp as recited in claim 6, wherein the high voltage plate comprises an edge radius which is larger than one half of the plate thickness.
- 8. The lamp as recited in claim 1, further comprising a heat transfer structure providing a thermal conduction path from the capacitor structure to a heat dissipating structure.
- 9. The lamp as recited in claim 1, wherein the capacitor structure comprises a coaxial capacitor circuit, including:
a first capacitor comprising a first cylindrical sleeve; a second capacitor comprising a second cylindrical sleeve disposed at least partially inside the first cylindrical sleeve of the first capacitor; and insulators disposed in between the first and second sleeves, wherein the first and second capacitors are connected in series with a center conductor being connected at a junction of the series connection.
- 10. The lamp as recited in claim 1, further comprising:
an enclosure housing the resonant lamp circuit, the enclosure comprising thermally conductive structures for transferring heat from the lamp circuit, and wherein the enclosure comprises substantially flat outer surfaces for interfacing with further heat dissipating structures.
- 11. The lamp as recited in claim 10, wherein the lamp circuit comprises an excitation coil made from copper.
- 12. The lamp as recited in claim 10, wherein the enclosure comprises a base portion and a cover, and wherein a thermal gasket is disposed between the cover and the base.
- 13. The lamp as recited in claim 10, wherein the coil and capacitor structure are integrated in a single assembly, and wherein the capacitor structure comprises a multi-layer printed circuit board adapted to form a capacitor stack.
- 14. An inductively coupled electrodeless lamp, comprising:
an excitation coil; a capacitor structure connected to the excitation coil, the capacitor structure and excitation coil together forming a resonant lamp circuit; an electrodeless lamp bulb positioned proximate to the excitation coil, the bulb containing a fill which emits light when excited by RF energy; and an RF source connected to the resonant lamp circuit and adapted to provide RF energy for exciting the fill; and a structure encasing the bulb except for a light emitting aperture, the structure comprising a ceramic material configured to promote heat transfer away from the bulb along a thermal path other than radially with respect to an axis of the coil.
- 15. The lamp as recited in claim 14, wherein the ceramic material comprises a high thermal conductivity material.
- 16. The lamp as recited in claim 15, wherein the material exhibits relatively higher thermal conductivity along a direction and wherein the material is adapted such that the direction of higher thermal conductivity is aligned with an axis of the coil.
- 17. The lamp as recited in claim 16, wherein the material comprises boron nitride.
- 18. The lamp as recited in claim 14, further comprising an enclosure housing the resonant lamp circuit, and wherein the structure comprises a ceramic cup with a flange, and wherein a resilient, thermally conductive material is disposed between the flange and a heat dissipating structure inside the enclosure.
- 19. The lamp as recited in claim 14, wherein the structure comprises:
a ceramic cylindrical rod defining a cavity at one end which is adapted to receive the bulb, wherein the bulb is disposed in the cavity; and a ceramic washer defining an aperture and disposed against the bulb, whereby the bulb is cooled relatively more from the portion of the bulb opposite from the aperture.
- 20. The lamp as recited in claim 14, wherein the structure comprises:
a relatively tall cylindrical and hollow structure adapted to support a bulb along its axial dimension so that at least a portion of the cylindrical cup extends significantly beyond the bulb in each axial direction.
- 21. The lamp as recited in claim 14, wherein the bulb bears a high temperature, high reflectivity, and wide angle dichroic coating except in a region which defines the aperture, and wherein the structure comprises a high thermal conductivity ceramic encasing the bulb except for an opening in the region of the aperture.
- 22. An oscillator, comprising:
an amplifier having an input and an output; and an impedance transformation network connected between the input of the amplifier and the output of the amplifier, the impedance transformation network being configured to provide suitable positive feedback from the output of the amplifier to the input of the amplifier to initiate and sustain an oscillating condition, the impedance matching network being further configured to protect the input of the amplifier from a destructive feedback signal, wherein the impedance transformation network comprises dual asymmetrical feedback paths adapted to provide an increased tuning range as compared to dual symmetrical feedback paths.
- 23. The oscillator as recited in claim 22, wherein the amplifier comprises two RF power FET transistors connected in parallel and configured with soft gate switching.
- 24. The oscillator as recited in claim 22, further comprising a gate pad with a perpendicular transmission line extending therefrom and forming a resonant “T”, wherein the feedback network is attached to the leg of the resonant “T”.
- 25. The oscillator as recited in claim 22, further comprising a continuously variable tuning circuit for adjusting the operating frequency of the oscillator.
- 26. The oscillator as recited in claim 25, wherein the tuning circuit consists of solid state electrical components with no mechanically adjustable devices.
- 27. The oscillator as recited in claim 26, wherein the tuning circuit comprises a plurality of PIN diode circuits configured as voltage controlled resistors.
- 28. The oscillator as recited in claim 26, wherein the tuning circuit comprises a complementary PIN diode circuit.
- 29. The oscillator as recited in claim 28, further comprising a heat transfer structure providing a thermal conduction path from the PIN diode to a heat dissipating structure.
- 30. The oscillator as recited in claim 29, wherein the heat transfer structure comprises a metal post soldered to one pad of the PIN diode and the heat dissipating structure comprises an electrically grounded heat spreader plate.
- 31. The oscillator as recited in claim 22, wherein the impedance transformation network is adapted to combine a first portion of feedback from a load connected to the oscillator with a second portion of feedback from the amplifier to control a relative angle between lines of constant current and lines of constant frequency as plotted on a Rieke diagram.
- 32. The oscillator as recited in claim 22, further comprising:
a load connected to the oscillator; at least one impedance element connected to either the oscillator or the load by a switch; and a control circuit adapted to operate the switch at least once during operation of the oscillator.
- 33. The oscillator as recited in claim 32, wherein the control circuit is adapted to operate the switch a pre-determined amount of time after the oscillator is started.
- 34. The oscillator as recited in claim 32, wherein the load comprises an electrodeless discharge lamp and the control circuit is adapted to operate the switch based on a sensed lamp condition.
- 35. The oscillator as recited in claim 32, wherein the at least one impedance element comprises first and second impedance elements with the first impedance element connected to the oscillator by a first switch and the second impedance element connected to the load by a second switch.
- 36. The oscillator as recited in claim 32, wherein the load comprises an electrodeless discharge lamp and wherein the control circuit is adapted to operate the switch in accordance with providing closer matching of an impedance of the oscillator and the load during starting.
- 37. The oscillator as recited in claim 32, wherein the load comprises an electrodeless discharge lamp and wherein the control circuit is adapted to operate the switch in accordance with avoiding a region of unstable oscillator operation during starting.
- 38. A lamp apparatus, comprising:
a discharge lamp; an RF power source connected to the discharge lamp for providing RF power to the lamp; and an RF control circuit adapted to control an operating parameter of the RF power source during operation.
- 39. The lamp as recited in claim 38, wherein the operating parameter corresponds to a frequency of the RF power source, the lamp further comprising:
a six port directional coupler connected in between the RF power source and the discharge lamp, the six port directional coupler being configured to detect forward and reflected power and provided respective signals representative thereof, and wherein the RF control circuit is configured to receive the signals representative of forward and reflected power and to adjust an operating frequency of the RF power source in accordance with the received signals.
- 40. The lamp apparatus as recited in claim 39, wherein the control circuit is configured to delay initiation of active control until after the oscillator starts.
- 41. The lamp apparatus as recited in claim 39, wherein the control circuit is configured to step an operating frequency of the oscillator through a range of frequencies until the lamp is determined to be operating at a resonant frequency.
- 42. The lamp apparatus as recited in claim 39, wherein the control circuit is configured to adjust an operating frequency of the oscillator to minimize reflected power.
- 43. The lamp as recited in claim 38, wherein the operating parameter corresponds to an amount of RF power coupled to the discharge lamp during operation.
- 44. The lamp as recited in claim 43, wherein the RF control circuit is adapted to provide less RF power to the lamp prior to ignition as compared to an amount of RF power provided during steady state operation, thereby reducing arcing potential and reflected power during starting.
- 45. The lamp as recited in claim 43, wherein the RF control circuit is adapted to temporarily provide more RF power to the lamp following ignition as compared to an amount of RF power provided during steady state operation, thereby bringing the lamp to full output faster.
- 46. The lamp as recited in claim 43, wherein the RF control circuit is adapted to adjust a supply voltage of the RF power source during steady state operation to provide at least one of substantially constant forward power and substantially constant light output.
- 47. The lamp as recited in claim 38, wherein the operating parameter corresponds to an amount of gate bias current provided to an active element of the RF power source.
- 48. The electrodeless lamp as recited in claim 47, wherein the gate bias current is controlled such that the RF power source is not turned on until other functions of the RF control circuit have initialized.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to U.S. Provisional patent application nos. 60/141,891, filed Jul. 2, 1999, 60/144,834, filed Jul. 21, 1999, 60/157,104, filed Oct. 4, 1999, 60/188,205, filed Mar. 10, 2000, and 60/210,154, filed Jun. 2, 2000, each of which is herein incorporated by reference in its entirety.
Government Interests
[0002] Certain inventions described herein were made with Government support under Contract No. DE-FC01-97EE23776 awarded by the Department of Energy or Contract No. NAS10-99037 awarded by National Aeronautics and Space Administration. The Government has certain rights in those inventions.
Provisional Applications (5)
|
Number |
Date |
Country |
|
60141891 |
Jul 1999 |
US |
|
60144834 |
Jul 1999 |
US |
|
60157104 |
Oct 1999 |
US |
|
60188205 |
Mar 2000 |
US |
|
60210154 |
Jun 2000 |
US |
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/US00/16302 |
Jun 2000 |
US |
Child |
09776698 |
Feb 2001 |
US |