Electrodeless lamp having compound resonant structure

Claim 2

An electrodeless lamp comprising, a microwave cavity, a bulb containing a plasma forming medium in said cavity, means for generating microwave energy, and means for coupling the generated microwave energy to said cavity, wherein said cavity comprises a compound resonant structure having first and second discrete portions of different cross-sectional areas, there being a discontinuity in said cavity between said first and second portions where said cross-sectional area changes, said microwave energy being coupled to said first cavity portion, and said bulb being located substantially within said second cavity portion, said second cavity portion comprising a reflector for reflecting radiation emitted by said bulb out of said cavity.

Claim 3

The electrodeless lamp of claim 1 wherein said second portion of said cavity has a greater height than said first portion.

Claim 4

The electrodeless lamp of claim 2 wherein the cross-sectional area of first portion is greater than the cross-sectional area of said second portion.

Claim 5

The electrodeless lamp of claim 3 wherein said reflector has a mouth, and a mesh is disposed across the mouth.

Claim 6

The electrodeless lamp of claim 4 wherein said first and second portions of said resonant microwave structure are of different cross-sectional shapes.

Claim 7

The electrodeless lamp of claim 5 wherein the electric field in said compound resonant structure is generally parallel to its height dimension.

Claim 8

The electrodeless lamp of claim 5 wherein the cross-sectional shape of said first cavity portion is rectangular and the cross-sectional shape of said second cavity portion is circular.

Claim 9

The electrodeless lamp of claim 6 wherein the cross-sectional shape of said first cavity portion is rectangular and the cross-sectional shape of said second cavity portion is circular.

Claim 10

The electrodeless lamp of claim 7 wherein the bulb is mounted in the cavity by a stem, and the stem is disposed at the location of a standing wave minimum.

Claim 11

The electrodeless lamp of claim 7 wherein said microwave energy is coupled to an end of said rectangular portion of said resonant microwave structure.

Claim 12

The electrodeless lamp of claim 7 wherein said microwave energy is coupled to a top or bottom face of said rectangular portion of said resonant microwave structure.

Claim 13

The electrodeless lamp of claim 7 wherein said microwave energy is coupled to a side of the rectangular first portion of said resonant microwave structure.

Claim 14

The electrodeless lamp of claim 7 wherein a dimension of the rectangular first portion of said compound resonant structure is adjustable.

Claim 15

An electrodeless lamp comprising, a microwave cavity, a bulb containing a plasma forming medium in said cavity, means for generating microwave energy, and means for coupling the generated microwave energy to said cavity, wherein said cavity comprises a compound resonant structure having first and second portions of different cross-sectional shape, said means for coupling microwave energy being arranged to couple such energy to said first portion, and said bulb being located substantially in said second portion.

Claim 16

An electrodeless lamp comprising, a microwave cavity, a bulb containing a plasma forming medium in said cavity, means for generating microwave energy, and means for coupling the generated microwave energy to said cavity, wherein said cavity comprises a compound resonant structure having first and second portions of different cross-sectional shape, said means for coupling microwave energy being arranged to couple such energy to said first portion, and said bulb being located substantially in said second portion.

Claim 17

The electrodeless lamp of claim 14 wherein said first portion of said cavity is rectangular in cross-section and said second portion is circular in cross-section.

Claim 18

The electrodeless lamp of claim 15 wherein said second portion of said cavity comprises a reflector for reflecting light emitted by said bulb out of said cavity.

Claim 19

The electrodeless lamp of claim 16 wherein said reflector has a mouth which is closed by a mesh.

Claim 20

The electrodeless lamp of claim 17 wherein said first and second cavity portions have a height dimension which is perpendicular to said cross-sectional shapes and wherein the electric field in said compound resonant structure is generally parallel to said height dimension.

Claim 21

The electrodeless lamp of claim 16 wherein said second portion of said cavity is of greater height than said first portion, and wherein said first portion has a constant cross-sectional dimension over its height while said second portion has a varying cross-sectional dimension over its height.

Claim 22

An electrodeless lamp which couples to a small bulb and achieves relatively high light output therefrom, comprising, a microwave cavity, a bulb containing a plasma forming medium located in said cavity, means for generating microwave energy, and means for coupling the generated microwave energy to said cavity, wherein said cavity is a compound resonant structure of dimensional configuration in relation to the frequency of said microwave energy such that the electric field in the cavity is generally parallel to the height dimension thereof and wherein the height dimension is small enough so that a field of requisite strength is coupled to said bulb, and wherein said compound resonant structure is comprised of first and second discrete portions, said second portion having greater height than said first portion but said first portion having a larger cross-sectional dimension than said second portion, said microwave energy being fed to said first portion, and said bulb being located substantially in said second portion, wherein said second portion is a reflector for reflecting light emitted by said bulb out of said cavity.

Claim 23

An electrodeless lamp which couples to a small bulb and achieves relatively high light output therefrom, comprising, a microwave cavity, a bulb containing a plasma forming medium located in said cavity, means for generating microwave energy, and means for coupling the generated microwave energy to said cavity, wherein said cavity is a compound resonant structure of dimensional configuration in relation to the frequency of said microwave energy such that the electric field in the cavity is generally parallel to the height dimension thereof and wherein the height dimension is small enough so that a field of requisite strength is coupled to said bulb, and wherein said compound resonant structure is comprised of first and second discrete portions, said second portion having greater height than said first portion but said first portion having a larger cross-sectional dimension than said second portion, said microwave energy being fed to said first portion, and said bulb being located substantially in said second portion, wherein said second portion is a reflector for reflecting light emitted by said bulb out of said cavity.

Claim 24

The electrodeless lamp of claim 20 wherein the cross-sectional shape of said first portion of said compound resonant structure is rectangular and the cross-sectional shape of said second portion is circular.

Claim 25

An electrodeless lamp comprising a microwave cavity, a bulb containing a plasma forming medium in said cavity, means for generating microwave energy, and means for coupling the generated microwave energy to said cavity, wherein said cavity comprises a compound resonant structure comprised of first and second discrete portions, said first portion having a greater cross-sectional area than said second portion, while said second portion has a greater height than said first portion, said microwave energy being coupled to said first portion, and said second portion having a cross-sectional area which varies across its height.

Claim 26

An electrodeless lamp comprising a microwave cavity, a bulb containing a plasma forming medium in said cavity, means for generating microwave energy, and means for coupling the generated microwave energy to said cavity, wherein said cavity comprises a compound resonant structure comprised of first and second discrete portions, said first portion having a greater cross-sectional area than said second portion, while said second portion has a greater height than said first portion, said microwave energy being coupled to said first portion, and said second portion having a cross-sectional area which varies across its height.

Claim 27

The electrodeless lamp of claim 22 wherein the cross-sectional shape of said second portion is circular while the cross-sectional shape of said first portion is rectangular.

Claim 28

The electrodeless lamp of claim 23 wherein the cross-sectional area of said first portion is substantially the same across its height.