Electrodeless low-pressure discharge lamp with plasma channel

Claim 2

An electrodeless low-pressure discharge lamp, comprising a lamp envelope (1) having a first end portion (9) and a second end portion (10); a generally cylindrical element (2) inside said envelope (1), formed with an aperture defining a linear channel (3) from near said first end portion (9) of said envelope to near said second end (10) portion thereof; a gas fill sealed in said envelope and extending through said channel (3), and adapted for ionization to form a plasma; a cylindrical excitation coil (6) surrounding said envelope (1) and connected to a generator (16) for generating a high-frequency electromagnetic field, said gas fill forming a plasma in response to application of said electromagnetic field; wherein said aperture has a substantially smaller diameter than portions (9, 10) of said envelope beyond axial ends of said cylindrical element (2), thereby confining any arc discharge occurring in said plasma to said smaller diameter, and causing radiation from said arc discharge to be preferentially emitted along an optical axis (4) coinciding with said linear channel (3); and wherein said cylindrical element (2) is made from a high-temperature-constant material.

Claim 3

The lamp of claim 1, wherein said cylindrical element (2) is provided with said channel for emitting said radiation in opposite directions.

Claim 4

The lamp of claim 1, wherein at least one end of the channel is conically flared.

Claim 5

The lamp of claim 1, wherein said cylindrical element (2) is made from quartz glass.

Claim 6

The lamp of claim 1, wherein said cylindrical element (2) is made from a metal oxide ceramic.

Claim 7

The lamp of claim 1, wherein said cylindrical element (2) is made from a metal nitride.

Claim 8

The lamp of claim 1, wherein said cylindrical element (2) is made from molybdenum.

Claim 9

The lamp of claim 1, wherein said cylindrical element (2) is made from diamond.

Claim 10

The lamp of claim 1, wherein said cylindrical element (2) is made from graphite.

Claim 11

The lamp of claim 1, wherein said envelope filling is hydrogen.

Claim 12

The lamp of claim 1, wherein said envelope filling is a noble gas.

Claim 13

The lamp of claim 10, wherein said hydrogen consists essentially of deuterium.

Claim 14

An electrodeless low-pressure discharge lamp comprising first and second discharge chambers (1, 1'), each of said first and second discharge chambers comprising a lamp envelope (1, 1') having a first end portion (9, 9') and a second end portion (10, 10'); a generally cylindrical element (2) inside said envelope (1), formed with an aperture defining a linear channel (3, 3') from near said first end portion (9) of said envelope to near said second end portion (10) thereof; a gas fill sealed in said envelope and extending through said channel (3), and adapted for ionization to form a plasma; a cylindrical excitation coil (6, 6') surrounding said envelope (1, 1') and connected to a generator (16, 16') for generating a high-frequency electromagnetic field, said gas fill forming a plasma in response to application of said electromagnetic field; each aperture has a substantially smaller diameter than portions (9, 10) of said envelope beyond axial ends of said cylindrical element (2), thereby confining any arc discharge occurring in said plasma to said smaller diameter, and causing radiation from said arc discharge to be preferentially emitted along an optical axis (4) coinciding with said linear channel (3); and wherein said channels in said cylindrical elements define respective optical axes (4, 4') extending along a common straight line.

Claim 15

An electrodeless low-pressure discharge lamp comprising first and second discharge chambers (1, 1'), each of said first and second discharge chambers comprising a lamp envelope (1, 1') having a first end portion (9, 9') and a second end portion (10, 10'); a generally cylindrical element (2) inside said envelope (1), formed with an aperture defining a linear channel (3, 3') from near said first end portion (9) of said envelope to near said second end portion (10) thereof; a gas fill sealed in said envelope and extending through said channel (3), and adapted for ionization to form a plasma; a cylindrical excitation coil (6, 6') surrounding said envelope (1, 1') and connected to a generator (16, 16') for generating a high-frequency electromagnetic field, said gas fill forming a plasma in response to application of said electromagnetic field; each aperture has a substantially smaller diameter than portions (9, 10) of said envelope beyond axial ends of said cylindrical element (2), thereby confining any arc discharge occurring in said plasma to said smaller diameter, and causing radiation from said arc discharge to be preferentially emitted along an optical axis (4) coinciding with said linear channel (3); and wherein said channels in said cylindrical elements define respective optical axes (4, 4') extending along a common straight line.