Electrodeless plasma lamp systems and methods

Abstract

Systems and methods for an electrodeless plasma lamp as described. A drive probe is coupled to the lamp body to provide the primary power for ignition and steady state operation of the lamp. Feedback is used to adjust frequency in response to changing conditions of the lamp during startup. A phase shifter is used to adjust the phase of the power between ignition and steady state operation. A sensor may detect a lamp operating condition that automatically triggers a shift in phase after the fill in the bulb is vaporized. The phase shift may then continue to be adjusted as the plasma heats up and the impedance continues to change. The bias conditions of an amplifier may be changed to change the operating class of the amplifier for different modes of the lamp.

1 . An electrodeless plasma lamp comprising:
 a lamp body comprising a dielectric material having a relative permittivity greater than 2;   a bulb proximate the lamp body, the bulb containing a fill that forms a plasma when radio frequency (RF) power is coupled to the fill from the lamp body, the fill including a gas and at least one metal halide; and   a lamp drive circuit for providing RF power to the lamp body;   wherein the RF power is provided to the fill to vaporize the metal halide and emit light; and   wherein the lamp drive circuit is configured to adjust the RF power provided to the fill after light is emitted by the vaporized metal halide to maintain a substantially constant brightness as the load conditions of the plasma change during heat up of the plasma.   
     
     
         2 . The electrodeless lamp of  claim 1 , wherein the lamp drive circuit is configured to provide the RF power at a frequency that forms a standing wave within the lamp body. 
     
     
         3 . The electrodeless lamp of  claim 1 , wherein the lamp drive circuit is configured to provide the RF power at a frequency that is within the resonant bandwidth of a resonant mode for the lamp body. 
     
     
         4 . The electrodeless plasma lamp of  claim 3 , wherein the resonant mode is the fundamental resonant mode for the lamp body. 
     
     
         5 . The electrodeless lamp of any of  claim 1 ,  2 ,  3  or  4 , wherein the lamp drive circuit is configured to adjust the RF power by adjusting the frequency of the RF power. 
     
     
         6 . The electrodeless plasma lamp of  claim 5 , wherein the lamp drive circuit is configured to adjust the frequency of the RF power frequency by adjusting a phase shifter in the lamp drive circuit. 
     
     
         7 . The electrodeless plasma lamp of any of  claim 1 ,  2 ,  3  or  4 , wherein the lamp drive circuit includes an amplifier and a control circuit configured to adjust the gain of the amplifier. 
     
     
         8 . The electrodeless lamp of any of  claim 1 ,  2 ,  3  or  4 , wherein the lamp drive circuit includes a feedback loop that samples power from the lamp body. 
     
     
         9 . The electrodeless lamp of  claim 5  or  claim 6 , wherein the lamp drive circuit includes a feedback loop that samples power from the lamp body. 
     
     
         10 . The electrodeless lamp of any of  claim 1 ,  2 ,  3  or  4 , further comprising a sensor for detecting a lamp operating condition, wherein the lamp drive circuit adjusts the RF power in response to a signal from the sensor. 
     
     
         11 . The electrodeless lamp of  claim 10 , wherein the sensor is a light sensor that detects light output intensity from the bulb. 
     
     
         12 . The electrodeless lamp of  claim 10 , wherein the sensor is a power sensor. 
     
     
         13 . The electrodeless plasma lamp of  claim 5 , further comprising a sensor for detecting a lamp operating condition, wherein the lamp drive circuit adjusts the frequency in response to a signal from the sensor. 
     
     
         14 . The electrodeless lamp of  claim 13 , wherein the sensor is a light sensor that detects light output intensity from the bulb. 
     
     
         15 . The electrodeless lamp of  claim 13 , wherein the sensor is a power sensor. 
     
     
         16 . The electrodeless plasma lamp of any of  claim 1 ,  2 ,  3  or  4 , wherein the lamp drive circuit is configured to adjust the RF power in a series of at least 5 adjustments after the output intensity of the bulb reaches a threshold. 
     
     
         17 . The electrodeless lamp of  claim 5 , wherein the frequency is ramped down in a series of adjustments after the output intensity of the bulb reaches a threshold. 
     
     
         18 . The electrodeless lamp of  claim 16 , wherein the threshold is a detected level of brightness that is within the range of about 10% to 90% of the peak visible brightness for the lamp. 
     
     
         19 . The electrodeless lamp of  claim 17 , wherein the threshold is a detected level of brightness that is within the range of about 10% to 90% of the peak visible brightness for the lamp. 
     
     
         20 . The electrodeless lamp of  claim 17 , wherein the lamp drive circuit is configured to adjust the frequency of the RF power by making a series of adjustments to a phase shifter in the lamp drive circuit. 
     
     
         21 . The electrodeless lamp of  claim 17 , wherein the frequency is ramped in a series of at least 10 adjustments. 
     
     
         22 . The electrodeless lamp of  claim 20 , wherein the frequency is ramped in a series of at least 10 adjustments. 
     
     
         23 . The electrodeless lamp of any of  claim 1 ,  2 ,  3  or  4 , wherein the drive circuit is configured to maintain the brightness within about 3% of a constant value. 
     
     
         24 . The electrodeless lamp of any of  claims 5 , wherein the drive circuit is configured to maintain the brightness within about 3% of a constant value after light is emitted by the vaporized metal halide. 
     
     
         25 . The electrodeless lamp of any of  claims 5 , wherein the drive circuit is configured to maintain the brightness within about 3% of a constant value after light is emitted by the vaporized metal halide. 
     
     
         26 . An electrodeless plasma lamp comprising:
 a resonant structure comprising a solid dielectric material and an electrically conductive material;   a bulb proximate the resonant structure, the bulb containing a fill that forms a plasma when radio frequency (RF) power is coupled to the fill from the resonant structure, the fill including a gas and at least one metal halide; and   a lamp drive circuit for providing RF power to the resonant structure at a frequency within a resonant bandwidth for the resonant structure such that the RF power is coupled to the fill to vaporize the metal halide and emit light;   wherein the lamp drive circuit is configured to adjust the RF power provided to the fill after light is emitted by the vaporized metal halide to maintain a brightness within a range of a constant value as the load conditions of the plasma change during heat up of the plasma.   
     
     
         27 . The electrodeless plasma lamp of  claim 26 , wherein the range is about 5% of the constant value. 
     
     
         28 . The electrodeless plasma lamp of  claim 26 , wherein the range is about 3% of the constant value. 
     
     
         29 . The electrodeless plasma lamp of  claim 26 , wherein the range is about 1% of the constant value. 
     
     
         30 . The electrodeless lamp of  claims 26 , wherein the lamp drive circuit is configured to adjust the RF power by adjusting the frequency of the RF power. 
     
     
         31 . The electrodeless plasma lamp of  claim 30 , wherein the lamp drive circuit is configured to adjust the frequency of the RF power frequency by adjusting a phase shifter in the lamp drive circuit. 
     
     
         32 . The electrodeless plasma lamp of  claim 26 , wherein the lamp drive circuit includes an amplifier and a control circuit configured to adjust the gain of the amplifier. 
     
     
         33 . The electrodeless plasma lamp of any of  claim 26 ,  27 ,  28 ,  29 ,  30 ,  31  or  32 , wherein the lamp drive circuit is configured to adjust the RF power based on a lamp operating condition. 
     
     
         34 . The electrodeless plasma lamp of  claim 33 , wherein the lamp operating condition is a signal representing the brightness of the lamp. 
     
     
         35 . The electrodeless plasma lamp of  claim 33 , wherein the lamp operating condition is a signal representing a power level in the lamp drive circuit. 
     
     
         36 . The electrodeless plasma lamp of  claim 33 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         37 . The electrodeless plasma lamp of any of  claim 26 ,  27 ,  28 ,  29 ,  30 ,  31  or  32 , wherein the lamp body has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         38 . A method comprising:
 providing a lamp body comprising a dielectric material having a relative permittivity greater than 2;   positioning a bulb proximate the lamp body, the bulb containing a fill, the fill including a gas and at least one metal halide;   coupling power to the fill through the lamp body to vaporize the metal halide and emit light; and   adjusting the RF power after light is emitted by the vaporized metal halide to maintain a brightness within a range of a constant value as the load conditions of the plasma change during heat up of the plasma.   
     
     
         39 . The method of  claim 38 , wherein the range is about 5% of the constant value. 
     
     
         40 . The method of  claim 38 , wherein the range is about 3% of the constant value. 
     
     
         41 . The method of  claim 38 , wherein the range is about 1% of the constant value. 
     
     
         42 . The method of  claim 38 ,  39 ,  40  or  41 , wherein adjusting the RF power comprises adjusting the frequency of the RF power. 
     
     
         43 . The electrodeless plasma lamp of any of  claim 1 ,  2 ,  3 ,  4 ,  26 ,  27 ,  28 ,  29 ,  30 ,  31  or  32 , wherein the bulb has an interior volume of less than about 100 mm 3 . 
     
     
         44 . The electrodeless plasma lamp of any of  claims 1 ,  2 ,  3 ,  4 ,  26 ,  27 ,  28 ,  29 ,  30 ,  31  or  32 , wherein the net RF power provided by the lamp drive circuit is at least 100 watts after the vaporization of the metal halide. 
     
     
         45 . The electrodeless plasma lamp of  claim 43 , wherein the net RF power provided by the lamp drive circuit is at least 100 watts after the vaporization of the metal halide. 
     
     
         46 . The electrodeless plasma lamp of  claim 43 , wherein the net RF power provided by the lamp drive circuit is less than 100 watts prior to the vaporization of the metal halide. 
     
     
         47 . The electrodeless plasma lamp of  claim 44 , wherein the net RF power provided by the lamp drive circuit is less than 100 watts prior to the vaporization of the metal halide. 
     
     
         48 . The electrodeless plasma lamp of  claim 45 , wherein the net RF power provided by the lamp drive circuit is less than 100 watts prior to the vaporization of the metal halide. 
     
     
         49 . An electrodeless plasma lamp comprising:
 a resonant structure comprising a solid dielectric material and an electrically conductive material;   a bulb proximate the resonant structure, the bulb containing a fill that forms a plasma when radio frequency (RF) power is coupled to the fill from the resonant structure, the fill including a gas and at least one metal halide; and   a lamp drive circuit for providing RF power to the resonant structure at a frequency within a resonant bandwidth for the resonant structure such that the RF power is coupled to the fill to vaporize the metal halide and emit light;   the lamp drive circuit including an amplifier and an impedance control circuit configured to adjust an impedance between the amplifier and the resonant structure.   
     
     
         50 . The electrodeless plasma lamp of  claim 49 , wherein the impedance includes a variable capacitor. 
     
     
         51 . The electrodeless plasma lamp of  claim 49 , wherein the impedance control circuit is configured to adjust the impedance by adjusting a capacitance in the lamp drive circuit. 
     
     
         52 . The electrodeless plasma lamp of  claim 49 , wherein the impedance control circuit is configured to adjust the impedance by switching an impedance element in the lamp drive circuit. 
     
     
         53 . The electrodeless plasma lamp of any of  claim 49 ,  50 ,  51  or  52 , wherein the impedance control circuit is configured to adjust the impedance based on a lamp operating condition. 
     
     
         54 . The electrodeless plasma lamp of any of  claim 49 ,  50 ,  51  or  52 , wherein the impedance control circuit is configured to adjust the impedance from a first impedance prior to vaporization of the metal halide to a second impedance after vaporization of the metal halide. 
     
     
         55 . The electrodeless plasma lamp of any of  claim 49 ,  50 ,  51  or  52 , wherein the impedance control circuit comprises a timer circuit configured to determine the time at which to adjust the impedance. 
     
     
         56 . The electrodeless plasma lamp of any of  claim 49 ,  50 ,  51  or  52 , wherein the bulb has an interior volume of less than about 100 mm 3 . 
     
     
         57 . The electrodeless plasma lamp of any of  claim 49 ,  50 ,  51  or  52 , wherein the net RF power provided by the lamp drive circuit is at least 100 watts after the vaporization of the metal halide. 
     
     
         58 . The electrodeless plasma lamp of  claim 56 , wherein the net RF power provided by the lamp drive circuit is at least 100 watts after the vaporization of the metal halide. 
     
     
         59 . The electrodeless plasma lamp of any of  claim 49 ,  50 ,  51  or  52 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         60 . The electrodeless plasma lamp of  claim 56 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         61 . The electrodeless plasma lamp of  claim 58 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         62 . An electrodeless plasma lamp comprising:
 a bulb containing a fill that forms a plasma;   a power amplifier for providing radio frequency power to the plasma at a frequency in the range of about 50 MHz to 10 GHz, the power amplifier capable of operating in at least two classes of operation; and   control electronics configured to change the class of operation of the power amplifier.   
     
     
         63 . The plasma lamp of  claim 62 , further comprising a light sensor for detecting light output intensity from the bulb, wherein the control electronics is configured to change the class of operation of the power amplifier in response to a signal from the light sensor. 
     
     
         64 . The plasma lamp of  claim 62 , further comprising a power sensor for detecting power provided by the power amplifier, Wherein the control electronics is configured to change the class of operation of the power amplifier in response to a signal from the power sensor. 
     
     
         65 . The plasma lamp of any of  claim 62 ,  63  or  64 , wherein the control electronics is configured to change the class of the power amplifier by changing a gate bias of the power amplifier. 
     
     
         66 . The plasma lamp of any of  claim 62 ,  63  or  64 , further comprising a lamp body and a first radio frequency feed coupled to the power amplifier to provide radio frequency power to the lamp body, wherein the bulb is adjacent to the lamp body and the plasma receives the radio frequency power from the lamp body. 
     
     
         67 . The plasma lamp of  claim 66  wherein:
 the power amplifier is configured to provide RF power at a frequency that forms a standing wave within the lamp body.   
     
     
         68 . The plasma lamp of  claim 66  wherein:
 the lamp body comprising a dielectric material having a relative permittivity greater than 2; and   the power amplifier is configured to provide RF power at a frequency that is within the resonant bandwidth of a resonant mode for the lamp body.   
     
     
         69 . The plasma lamp of any of  claim 62 ,  63  or  64  wherein:
 the power amplifier is configured to operate as a class A/B amplifier during at least a first mode of operation and a class C amplifier during at least a second mode of operation.   
     
     
         70 . The plasma lamp of  claim 69 , wherein the first mode of operation is a startup mode during which the plasma warms up. 
     
     
         71 . The plasma lamp of  claim 69 , wherein the second mode of operation is steady state operation above a threshold level of brightness. 
     
     
         72 . The plasma lamp of  claim 70 , wherein the second mode of operation is steady state operation above a threshold level of brightness. 
     
     
         73 . The plasma lamp of  claim 69 , wherein the first mode of operation is a mode during which the plasma lamp operates below a threshold level of brightness. 
     
     
         74 . The plasma lamp of  claim 73  wherein the threshold is in the range of about 50% to 80% of peak brightness. 
     
     
         75 . An electrodeless plasma lamp comprising:
 a bulb containing a fill that forms a plasma;   a power amplifier for providing radio frequency power to the plasma at a frequency in the range of about 50 MHz to 10 GHz; and   control electronics configured to change the gate bias voltage of the power amplifier.   
     
     
         76 . The plasma lamp of  claim 75 , further comprising a light sensor for detecting light output intensity from the bulb, wherein the control electronics is configured to change the gate bias voltage of the power amplifier in response to a signal from the light sensor. 
     
     
         77 . The plasma lamp of  claim 75 , further comprising a power sensor for detecting power provided by the power amplifier, wherein the control electronics is configured to change the gate bias voltage of the power amplifier in response to a signal from the power sensor. 
     
     
         78 . The plasma lamp of any of  claim 75 ,  76 , or  77 , further comprising:
 a resonant structure comprising a solid dielectric material and an electrically conductive material, the resonant structure proximate the bulb;   wherein the power amplifier provides radio frequency power to the resonant structure at a frequency within a resonant bandwidth for the resonant structure.   
     
     
         79 . The electrodeless plasma lamp of  claim 78 ; wherein the bulb has an interior volume of less than about 100 mm 3 . 
     
     
         80 . The electrodeless plasma lamp of  claim 78 , wherein the net RF power provided by the lamp drive circuit is at least 100 watts after the vaporization of the metal halide. 
     
     
         81 . The electrodeless plasma lamp of  claim 80 ; wherein the net RF power provided by the lamp drive circuit is at least 100 watts after the vaporization of the metal halide. 
     
     
         82 . The electrodeless plasma lamp of  claim 78 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         83 . The electrodeless plasma lamp of  claim 79 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         84 . The electrodeless plasma lamp of  claim 80 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         85 . A method comprising:
 providing a bulb containing a fill that forms a plasma;   coupling power from an amplifier to the plasma at a frequency in the range of about 50 MHz to 10 GHz; and   adjusting the gate bias voltage of the power amplifier.   
     
     
         86 . The method of  claim 85 , wherein adjusting the gate bias voltage is based on a detected lamp operating condition. 
     
     
         87 . An electrodeless plasma lamp comprising:
 a lamp body comprising a dielectric material having a relative permittivity greater than 2;   a bulb adjacent to the lamp body, the bulb containing a fill that forms a plasma when RF power is coupled to the fill from the lamp body;   an RF feed coupled to the lamp body; and   a radio frequency (RF) power source for coupling power into the lamp body through the RF feed, the RF power source configured to provide RF power at a frequency that forms a standing wave within the lamp body;   wherein the shortest distance between an end of the bulb and an end of the RF feed traverses at least one electrically conductive material of the lamp body.   
     
     
         88 . The electrodeless plasma lamp of  claim 87 , wherein the electrically conductive material is spaced apart from the bulb and the drive probe. 
     
     
         89 . The electrodeless plasma lamp of  claim 87 , wherein the distance from the end of the bulb to the end of the RF feed is less than about 10 mm. 
     
     
         90 . The electrodeless plasma lamp of  claim 87 , wherein the distance from the end of the bulb to the end of the RF feed is greater than a distance from a side of the bulb to the end of the probe. 
     
     
         91 . The electrodeless plasma lamp of  claim 87  wherein a distance from the end of the bulb to the electrically conductive material is less than about 5 mm. 
     
     
         92 . The electrodeless plasma lamp of any of  claim 87 ,  88 ,  89 ,  90  or  91  wherein a distance from the end of the probe to the electrically conductive material is less than about 10 mm. 
     
     
         93 . The electrodeless plasma lamp of any of  claim 87 ,  88 ,  89 ,  90  or  91  wherein a distance from the end of the probe to the electrically conductive material is less than about 5 mm. 
     
     
         94 . The electrodeless plasma lamp of any of  claim 87 ,  88 ,  89 ,  90  or  91  wherein a distance from the end of the probe to a central axis of the lamp body is less than about 15 mm. 
     
     
         95 . The electrodeless plasma lamp of any of  claim 87 ,  88 ,  89 ,  90  or  91  wherein a distance from the end of the probe to a central axis of the lamp body is less than about 10 mm. 
     
     
         96 . The electrodeless plasma lamp of  claim 95  wherein the bulb is positioned such that at least a portion of the bulb intersects the central axis. 
     
     
         97 . The electrodeless plasma lamp of  claim 96  wherein the bulb is positioned such that at least a portion of the bulb intersects the central axis. 
     
     
         98 . The electrodeless plasma lamp of any  claim 87 ,  88 ,  89 ,  90  or  91  wherein the interior bulb volume is less than about 100 mm 3 . 
     
     
         99 . The electrodeless plasma lamp of any of  claim 87 ,  88 ,  89 ,  90  or  91  wherein the RF feed is a probe having a diameter greater than about 1.5 mm. 
     
     
         100 . The electrodeless plasma lamp of  claim 87 ,  88 ,  89 ,  90  or  91  wherein the drive probe has a length greater than about 10 mm. 
     
     
         101 . An electrodeless plasma lamp comprising:
 a resonant structure comprising a solid dielectric material and an electrically conductive material;   a bulb proximate the resonant structure, the bulb containing a fill that forms a plasma when RF power is coupled to the fill from the resonant structure; and   a probe configured to couple the RF power into the resonant structure at a frequency within the resonant bandwidth for the resonant structure, wherein an end of the probe is spaced apart from the electrically conductive material by the solid dielectric material;   wherein the distance between the end of the probe and the electrically conductive material is in the range of about 1 mm to 10 mm.   
     
     
         102 . The electrodeless plasma lamp of  claim 101 , wherein the distance between the end of the probe and the electrically conductive material is less than about 5 mm. 
     
     
         103 . The electrodeless plasma lamp of  claim 101 , wherein the distance between the end of the probe and the electrically conductive material is less than about 3 mm. 
     
     
         104 . The electrodeless plasma lamp of  claim 101 , wherein a distance from the end of the probe to a central axis of the resonant structure is less than about 15 mm. 
     
     
         105 . The electrodeless plasma lamp of  claim 101 , wherein a distance from the end of the probe to a central axis of the resonant structure is less than about 10 mm. 
     
     
         106 . The electrodeless plasma lamp of  claim 101 , wherein a distance from the end of the probe to a central axis of the resonant structure is greater than about 5 mm. 
     
     
         107 . The electrodeless plasma lamp of  claim 105 , wherein a distance from the end of the probe to a central axis of the resonant structure is greater than about 3 mm. 
     
     
         108 . The electrodeless plasma lamp of  claim 101 , wherein a distance from the end of the probe to the bulb is less than about 10 mm. 
     
     
         109 . The electrodeless plasma lamp of any of  claim 101 ,  102 ,  103 ,  104 ,  105 ,  106 ,  107  or  108 , wherein the bulb has an interior volume of less than about 100 mm 3 . 
     
     
         110 . The electrodeless plasma lamp of  claim 109 , wherein the net RF power provided by the lamp drive circuit is at least 100 watts after the vaporization of the metal halide. 
     
     
         111 . The electrodeless plasma lamp of any of  claim 101 ,  102 ,  103 ,  104 ,  105 ,  106 ,  107  or  108 , wherein the net RF power provided by the lamp drive circuit is at least 100 watts after the vaporization of the metal halide. 
     
     
         112 . The electrodeless plasma lamp of any of  claim 101 ,  102 ,  103 ,  104 ,  105 ,  106 ,  107  or  108 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         113 . The electrodeless plasma lamp of  claim 109 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         114 . The electrodeless plasma lamp of  claim 110 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         115 . The electrodeless plasma lamp of  claim 111 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 30 cm 3 . 
     
     
         116 . The electrodeless plasma lamp of any of  claim 101 ,  102 ,  103 ,  104 ,  105 ,  106 ,  107  or  108 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 7 cm 3 . 
     
     
         117 . The electrodeless plasma lamp of  claim 109 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 7 cm 3 . 
     
     
         118 . The electrodeless plasma lamp of  claim 110 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 7 cm 3 . 
     
     
         119 . The electrodeless plasma lamp of  claim 111 , wherein the solid dielectric material has a volume in the range of about 4 cm 3  to 7 cm 3 . 
     
     
         120 . The electrodeless plasma lamp of  claim 109 , wherein the frequency is less than about 1 GHz. 
     
     
         121 . The electrodeless plasma lamp of  claim 110 , wherein the frequency is less than about 1 GHz. 
     
     
         122 . The electrodeless plasma lamp of  claim 111 , wherein the frequency is less than about 1 GHz. 
     
     
         123 . The electrodeless plasma lamp of  claim 112 , wherein the frequency is less than about 1 GHz. 
     
     
         124 . The electrodeless plasma lamp of  claim 113 , wherein the frequency is less than about 1 GHz. 
     
     
         125 . The electrodeless plasma lamp of  claim 114 , wherein the frequency is less than about 1 GHz. 
     
     
         126 . The electrodeless plasma lamp of  claim 115 , wherein the frequency is less than about 1 GHz. 
       GHz. 
     
     
         127 . The electrodeless plasma lamp of  claim 116 , wherein the frequency is less than about 2.5 GHz. 
     
     
         128 . The electrodeless plasma lamp of  claim 117 , wherein the frequency is less than about 2.5 GHz. 
     
     
         129 . The electrodeless plasma lamp of  claim 118 , wherein the frequency is less than about 2.5 GHz. 
     
     
         130 . The electrodeless plasma lamp of  claim 119 , wherein the frequency is less than about 2.5 GHz.