Discharge lamp

Abstract

A discharge lamp includes a coaxial waveguide for high-frequency electromagnetic wave transmission and a discharge tube for emitting light of discharge by plasma generated by electromagnetic waves. The coaxial waveguide includes an internal conductor and a pipe-shaped external conductor surrounding the internal conductor. The discharge tube is attached to a top of the coaxial waveguide, and is constructed in a double end shape in which both ends of a glass tube are pinched and sealed. The glass tube includes an ellipse spherical bulged part formed in a middle of a longitudinal direction. An inside of the ellipse spherical bulged part forms discharge space. A conductor assembly is sealed and attached to at least a proximal side pinch seal part. The proximal side pinch seal part of the discharge tube is inserted and held in a top opening of the coaxial waveguide.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a longitudinal sectional view showing an outline of a discharge lamp which is a first embodiment of the invention.

FIG. 1( a) is an enlarged perspective view of fixing and holding means of a discharge tube which is a main part of the same discharge lamp.

FIG. 2 is views explaining the first half of a manufacturing process of a discharge tube, and 2(a) and 2(b) are views showing a process of molding an ellipse spherical bulged part, and 2(c) and 2(d) are views showing a primary pinch seal process, and 2(e) is a sectional view of a glass tube through the primary pinch seal process.

FIG. 3 is views explaining the second half of the manufacturing process of the discharge tube, and 3(a) is a view showing a pellet supply process, and 3(b) and 3(c) are views showing a conductor assembly insertion process, and 3(d) is a view showing a glass tube temporary seal process, and 3(e) is a view showing a secondary pinch seal process.

FIG. 4 is views explaining a shroud tube welding process, and 4(a) is a sectional view of the discharge tube before welding of the shroud tube, and 4(b) and 4(c) are views showing the shroud tube welding process.

FIG. 5 is a longitudinal sectional view showing an outline of a discharge lamp which is a second embodiment of the invention.

FIG. 6 is a longitudinal sectional view showing a modified example of an internal conductor constructing a waveguide of the same discharge lamp.

FIG. 7 is longitudinal sectional views of discharge tubes which are main parts of discharge lamps which are other embodiments of the invention, and 7(a) is a longitudinal sectional view of a discharge tube of a third embodiment, and 7(b) is a longitudinal sectional view of a discharge tube of a fourth embodiment, and 7(c) is a longitudinal sectional view of a discharge tube of a fifth embodiment, and 7(d) is a longitudinal sectional view of a discharge tube of a sixth embodiment, and 7(e) is a longitudinal sectional view of a discharge tube of a seventh embodiment, and 7(f) is a longitudinal sectional view of a discharge tube of an eighth embodiment.

FIG. 8 is an explanatory view explaining a process of covering a conductor bar protruding to discharge space with a cap part.

FIG. 9 is a diagram showing a lighting test result.

FIG. 10 is views explaining specifications of a discharge tube used in a lighting test.

FIG. 11 is a diagram showing a tube wall load test on a discharge valve in the first embodiment.

FIG. 12 is a diagram showing an electrode damage test on the discharge valve in the first embodiment.

FIG. 13 is the whole configuration diagram of a conventional discharge lamp.

FIG. 14 is a longitudinal sectional view of a discharge tube which is a main part of the same discharge lamp.

Claims

1. A discharge lamp comprising a coaxial waveguide for high-frequency electromagnetic wave transmission,wherein the coaxial waveguide comprises an internal conductor, anda pipe-shaped external conductor surrounding said internal conductor, and a discharge tube for emitting light of discharge by plasma generated by electromagnetic waves,wherein the discharge tube is attached to a top of the coaxial waveguide, andis constructed in a double end shape in which both ends of a glass tube are pinched and sealed,wherein the glass tube comprises an ellipse spherical bulged part formed in a middle of a longitudinal direction,wherein an inside of the ellipse spherical bulged part forms discharge space, wherein a conductor assembly is sealed and attached to at least a proximal side pinch seal part, andwherein an electromagnetic wave irradiation part is constructed by the conductor assembly and the external conductor top of the coaxial waveguide surrounding said conductor assembly by inserting and holding the proximal side pinch seal part of the discharge tube in a top opening of the waveguide so that the conductor assembly approaches the internal conductor of the coaxial waveguide.

2. A discharge lamp as claimed in claim 1, wherein the conductor assembly is constructed by linearly connecting and integrating a conductor bar and molybdenum foil.

3. A discharge lamp as claimed in claim 1, wherein a part of the conductor assembly sealed and attached to at least the proximal side pinch seal part among a pair of the pinch seal parts protrudes to the inside of the discharge space.

4. A discharge lamp as claimed in claim 3, wherein a region protruding to the inside of the discharge space of the conductor assembly is surrounded by a ceramic coating or a glass cap part extending from the pinch seal part to which said conductor assembly is sealed and attached.

5. A discharge lamp as in claim 1, wherein the ellipse spherical bulged part is covered with hermetically sealed space defined by a cylindrical shroud for ultraviolet shielding welded to the pinch seal part.

6. A discharge lamp as claimed in claim 2, wherein a part of the conductor assembly sealed and attached to at least the proximal side pinch seal part among a pair of the pinch seal parts protrudes to the inside of the discharge space.

7. A discharge lamp as claimed in claim 6, wherein a region protruding to the inside of the discharge space of the conductor assembly is surrounded by a ceramic coating or a glass cap part extending from the pinch seal part to which said conductor assembly is sealed and attached.

8. A discharge lamp as in claim 2, wherein the ellipse spherical bulged part is covered with hermetically sealed space defined by a cylindrical shroud for ultraviolet shielding welded to the pinch seal part.

9. A discharge lamp as in claim 3, wherein the ellipse spherical bulged part is covered with hermetically sealed space defined by a cylindrical shroud for ultraviolet shielding welded to the pinch seal part.

10. A discharge lamp as in claim 4, wherein the ellipse spherical bulged part is covered with hermetically sealed space defined by a cylindrical shroud for ultraviolet shielding welded to the pinch seal part.

11. A discharge lamp as in claim 6, wherein the ellipse spherical bulged part is covered with hermetically sealed space defined by a cylindrical shroud for ultraviolet shielding welded to the pinch seal part.

12. A discharge lamp as in claim 7, wherein the ellipse spherical bulged part is covered with hermetically sealed space defined by a cylindrical shroud for ultraviolet shielding welded to the pinch seal part.

13. A discharge lamp comprising: a coaxial waveguide comprising an internal conductor and a pipe-shaped external conductor surrounding the internal conductor, anda discharge tube comprising: a glass tube having: an ellipse spherical bulged part formed in a middle of a longitudinal direction, an inside of which forms a discharge space, andboth ends pinched and sealed; anda conductor assembly sealed and attached to an end of the glass tube, andwherein the discharge tube is inserted conductor assembly end first and held in a top opening of the coaxial waveguide.

14. The discharge lamp of claim 13, wherein the discharge tube further comprises a second conductor assembly sealed and attached to the other end of the glass tube.

15. The discharge lamp of claim 13, wherein the ellipse spherical bulged part is covered with a shroud for ultraviolet shielding.

16. The discharge lamp of claim 13, wherein the conductor assembly is constructed by linearly connecting and integrating a conductor bar and molybdenum foil.

17. A method of manufacturing a discharge lamp comprising a coaxial waveguide and a discharge tube, the method comprising: constructing the discharge tube by forming an ellipse spherical bulged part in a middle of a longitudinal direction of a glass tube having a double end shape, wherein an inside of the ellipsespherical bulged part forms discharge space,pinching and sealing both ends of the glass tube, andsealing and attaching a conductor assembly to an end the glass tube;constructing the coaxial waveguide with an internal conductor and a pipe-shaped external conductor surrounding said internal conductor;adapting the coaxial waveguide to hold the discharge tube in a top opening thereof; andinserting the discharge tube conductor assembly end first into the top opening of the coaxial waveguide.

18. The method of manufacturing a discharge lamp of claim 17, wherein constructing the discharge tube further comprises sealing and attaching a second conductor assembly to the other end of the glass tube.

19. The method of manufacturing a discharge lamp of claim 17 further comprising: covering the ellipse spherical bulged part with a shroud for ultraviolent shielding.

20. The method of manufacturing a discharge lamp of claim 17, further comprising constructing the conductor assembly by linearly connecting and integrating a conductor bar and molybdenum foil.