Abstract: A lamp comprises a light source in the form of a light emitting resonator 1, a magnetron 2 and a stub tuner 3. A reflector 4 is fitted at the junction of the light source and the stub tuner, for directing the light in a generally collimated beam 5. The light emitting resonator comprises an enclosure 11 formed of inner and outer envelopes 12,13 of quartz. These are circular cylindrical tubes 14,15, with respective end plates 16,17. A tungsten wire mesh 18, of a mesh size to exhibit a ground plane to microwaves within the resonator, is sandwiched between the tubes and the end plates respectively. Each envelope, comprised of its tube and end plates is hermetic. An earth connection 18? extends from the mesh to the outside of the envelope. The length axially of the enclosure between the wire mesh sandwiched between the end plates is ?/2 for the operating microwave frequency. At one end of the enclosure, a molybdenum drive connection 19 extends to a tungsten disc 20.

Abstract: A plasma crucible has a through bore and two tubes butt scaled on to the end faces of the crucible. One of the tubes is closed prior to the filling of the crucible. The tube is tipped off and worked in a glass lathe to form it to have a flat end. After evacuation, dosing and gas fill, the other tube is tipped off in the similar manner.

Abstract: A light source to be powered by microwave energy, the source having: a body having a sealed void therein, a microwave-enclosing Faraday cage surrounding the body, a fill in the void of material excitable by microwave energy to form a light emitting plasma therein, and an antenna arranged within the body for transmitting plasma-inducing, microwave energy to the fill, the antenna having: a connection extending outside the body for coupling to a source of microwave energy; wherein the body is a solid plasma crucible of material which is lucent for exit of light therefrom, the plasma crucible is contoured with a contoured surface to reflect light internally within the lucent crucible material to exit in a particular direction, the Faraday cage is at least partially light transmitting for light exit from the plasma crucible in the particular direction.

Abstract: A lucent plasma crucible having a closed body for enclosing a fill material filled in a void formed within the closed body and enclosed by the closed body, the fill material being excitable by microwave energy to generate a light-emitting plasma. The crucible is dimensioned to have low order TE or TM microwave mode properties. The orders of the modes are 0, 1 or 2. Crucibles may be regular or irregular in shape. For circular cylindrical crucibles having diameter (d) in cm, length (l) in cm, and operating frequency (f) in MHZ, (d/l)2 is between 0 and 100, and (d×f)2 is between 0 and 2×109. Also 0<(d/l)2<20 and 0<(d×f)2<1.5×109 may be used.

Abstract: A lucent crucible of a Lucent Waveguide Microwave Plasma Light Source (LWMPLS) comprising a Light Emitting Resonator (LER) in form of a crucible (1) of fused quartz which has a central void (2) having microwave excitable material (3) within it. In one example, the void is 4 mm in diameter and has a length (L) of 21 mm. The LWMPLS is operated at a power (P) of 280 W and thus with a plasma loading P/L of 133 w/cm and a wall loading of 106 w/cm2. The lamp is thus operated with a high efficiency—in terms of lumens per watt—while having a reasonable lifetime.

Abstract: A lamp 1 comprises an oscillator and amplifier source 2 of microwave energy, typically operating at 2.45 or 5.8 GHz or other frequencies within an ISM band. The source passes the microwaves via a matching circuit 3 to an antenna 4 extending into a re -entrant 5 in a lucent waveguide 6. This is of quartz and has a central cavity 7 accommodating a bulb 8. The bulb is a sealed tube 9 of quartz and contains a fill of noble gas and a microwave excitable material, which radiates visible light when excited by microwaves. The bulb has a stem 10 received in a stem bore 11 extending from the central cavity. The waveguide is transparent and light from the bulb can leave it in any direction, subject to any reflective surfaces. Microwaves cannot leave the waveguide, which is limited at its surfaces by a Faraday cage.

Abstract: A method of applying a Faraday cage to a lucent resonator, the resonator having a void containing microwave-excitable material and being adapted for microwave resonance in the resonator and within the Faraday cage for driving a light emitting plasma in the void, the method consisting in the steps of: deposition of a conductive material onto the lucent resonator; applying, patterning and developing a photoresist material over the conductive material to leave the conductive material exposed where it is not required; removing the conductive material where not required and the photoresist material from the required conductive material, leaving a reticular network of conductive material providing a Faraday cage and depositing a layer of protective material over the cage of conductive material.

Abstract: A band pass filter comprises an air filled aluminium chamber, having a lid and a cuboid resonant cavity having a central iris. At opposite end nodes of the cavity, perfect electric conductors (PECs) are provided. One is connected to a feed wire from an input at one end of the cavity. The other PEC is connected via a further feed wire to a radiator in a fabrication of solid-dielectric, lucent material. Threaded tuning projections opposite the PECs and in the iris are provided, whereby the pass band and the transmission characteristics of the filter in the pass band can be tuned to match the input impedance of the band pass filter and the wave guide to the output impedance of a microwave drive circuit (not shown). Typically the impedance will be 50?.

Abstract: A light source is powered by a magnetron and has a quartz crucible having a plasma void with an excitable fill, from which light radiates in use. Two aluminium attachment blocks are attached together and the block is attached to a casing of the magnetron by screws - not shown. The quartz crucible is attached to the block by a Faraday cage, in the form of a perforate metal enclosure secured at its rim to the block. An output formation of the magnetron has a conductive, copper cap fitted in electrical contact with it. The cap is extended by a copper rod. The rod extends through the blocks into a bore in the crucible for coupling microwaves from the magnetron into the crucible. An airspace is provided around the cap in the block. From the cap, the rod extends with negligible air gap in an alumina ceramic tube through the airspace and a boss of the block located in an aperture in an end wall of the block.

Abstract: An electrodeless, microwave lamp has a magnetron as a microwave source and an excitable material lucent crucible in whose excitable material a plasma is established. For coupling microwaves from the magnetron into the crucible, an air wave guide coupling circuit is provided, with an output of the magnetron as an input at one quarter lambda from one end and an output at one quarter from the other end as an input to a connection to the crucible.

Abstract: A bandpass filter comprises an air filled aluminum chamber having a lid and a cuboid resonant cavity having a central iris. At opposite end nodes of the cavity, perfect electric conductors (PECs) are provided. Threaded tuning projections opposite the PECs and in the iris are provided, whereby the pass band and the transmission characteristics of the filter in the pass band can be tuned to match the input impedance of the band pass filter and the wave guide to the output impedance of a microwave drive circuit. It is mounted on one end of the filter chamber, with an electrodeless bulb in a central cavity directed axially away from the chamber and the radiator in a further cavity set to one side of the central cavity. When the filter is driven, the wave guide resonates driving the bulb.

Abstract: A plasma crucible has a through bore and two tubes butt scaled on to the end faces of the crucible. One of the tubes is closed prior to the filling of the crucible. The tube is tipped off and worked in a glass lathe to form it to have a flat end. After evacuation, dosing and gas fill, the other tube is tipped off in the similar manner.

Abstract: A lamp comprises a light source in the form of a light emitting resonator 1, a magnetron 2 and a stub tuner 3. A reflector 4 is fitted at the junction of the light source and the stub tuner, for directing the light in a generally collimated beam 5. The light emitting resonator comprises an enclosure 11 formed of inner and outer envelopes 12,13 of quartz. These are circular cylindrical tubes 14,15, with respective end plates 16,17. A tungsten wire mesh 18, of a mesh size to exhibit a ground plane to microwaves within the resonator, is sandwiched between the tubes and the end plates respectively. Each envelope, comprised of its tube and end plates is hermetic. An earth connection 18? extends from the mesh to the outside of the envelope. The length axially of the enclosure between the wire mesh sandwiched between the end plates is ?/2 for the operating microwave frequency. At one end of the enclosure, a molybdenum drive connection 19 extends to a tungsten disc 20.

Abstract: A lamp 1 comprises an oscillator and amplifier source 2 of microwave energy, typically operating at 2.45 or 5.8 GHz or other frequencies within an ISM band. The source passes the microwaves via a matching circuit 3 to an antenna 4 extending into a re-entrant 5 in a lucent waveguide 6. This is of quartz and has a central cavity 7 accommodating a bulb 8. The bulb is a sealed tube 9 of quartz and contains a fill of noble gas and a microwave excitable material, which radiates visible light when excited by microwaves. The bulb has a stem 10 received in a stem bore 11 extending from the central cavity. The waveguide is transparent and light from the bulb can leave it in any direction, subject to any reflective surfaces. Microwaves cannot leave the waveguide, which is limited at its surfaces by a Faraday cage.

Abstract: A lamp comprises a light source in the form of a light emitting resonator 1, a magnetron 2 and a stub tuner 3. A reflector 4 is fitted at the junction of the light source and the stub tuner, for directing the light in a generally collimated beam 5. The light emitting resonator comprises an enclosure 11 formed of inner and outer envelopes 12,13 of quartz. These are circular cylindrical tubes 14,15, with respective end plates 16,17. A tungsten wire mesh 18, of a mesh size to exhibit a ground plane to microwaves within the resonator, is sandwiched between the tubes and the end plates respectively. Each envelope, comprised of its tube and end plates is hermetic. An earth connection 18? extends from the mesh to the outside of the envelope. The length axially of the enclosure between the wire mesh sandwiched between the end plates is ?/2 for the operating microwave frequency. At one end of the enclosure, a molybdenum drive connection 19 extends to a tungsten disc 20.

Abstract: A lucent plasma crucible having a closed body for enclosing a fill material filled in a void formed within the closed body and enclosed by the closed body, the fill material being excitable by microwave energy to generate a light-emitting plasma. The crucible is dimensioned to have low order TE or TM microwave mode properties. The orders of the modes are 0, 1 or 2. Crucibles may be regular or irregular in shape. For circular cylindrical crucibles having diameter (d) in cm, length (l) in cm, and operating frequency (f) in MHZ, (d/l)2 is between 0 and 100, and (d×f)2 is between 0 and 2×109. Also 0<(d/l)2<20 and 0<(d×f)2<1.5×109 may be used.

Abstract: A lamp comprises a light source in the form of a light emitting resonator 1, a magnetron 2 and a stub tuner 3. A reflector 4 is fitted at the junction of the light source and the stub tuner, for directing the light in a generally collimated beam 5. The light emitting resonator comprises an enclosure 11 formed of inner and outer envelopes 12,13 of quartz. These are circular cylindrical tubes 14,15, with respective end plates 16,17. A tungsten wire mesh 18, of a mesh size to exhibit a ground plane to microwaves within the resonator, is sandwiched between the tubes and the end plates respectively. Each envelope, comprised of its tube and end plates is hermetic. An earth connection 18? extends from the mesh to the outside of the envelope. The length axially of the enclosure between the wire mesh sandwiched between the end plates is ?/2 for the operating microwave frequency. At one end of the enclosure, a molybdenum drive connection 19 extends to a tungsten disc 20.

Abstract: A bandpass filter comprises an air filled aluminum chamber having a lid and a cuboid resonant cavity having a central iris. At opposite end nodes of the cavity, perfect electric conductors (PECs) are provided. Threaded tuning projections opposite the PECs and in the iris are provided, whereby the pass band and the transmission characteristics of the filter in the pass band can be tuned to match the input impedance of the band pass filter and the wave guide to the output impedance of a microwave drive circuit. It is mounted on one end of the filter chamber, with an electrodeless bulb in a central cavity directed axially away from the chamber and the radiator in a further cavity set to one side of the central cavity. When the filter is driven, the wave guide resonates driving the bulb.