Electrode, and high-pressure discharge lamp comprising said electrode
An electrode ( 1 ) for a high-pressure discharge lamp, having an electrode head ( 3 ) and an electrode rod ( 2 ), connected to electrode head ( 3 ) and defines a longitudinal axis (L). The electrode head ( 3 ) comprises a main section ( 4 ) on the same side as the electrode rod ( 2 ), an intermediate section ( 5 ) and an end section ( 9 ) on the opposite side from the electrode rod ( 2 ). The end surface of the end section ( 9 ) of the electrode head ( 3 ) is formed at least approximately semicircularly, and at least one subsection of the intermediate section ( 5 ) is cylindrically shaped. The extent (D 2 ) of the cylindrical subsection of the intermediate section ( 5 ) in at least one direction perpendicular to the longitudinal axis is greater than the diameter (D 3 ) of the semicircular end surface of the end section ( 9 ), but less than the largest transverse extent (D 1 ) of the main section.
1. An electrode for a high-pressure discharge lamp, comprising:
an electrode head; and
an electrode rod connected to the electrode head and defining a longitudinal axis, the electrode head comprising:
a main section on the same side as the electrode rod;
an end section on the opposite side from the electrode rod; and
an intermediate section arranged between the end section and the main section;
wherein an end surface of the end section of the electrode head is formed at least approximately semicircularly, and at least one subsection of the intermediate section is cylindrically shaped; and
wherein an extent of the cylindrical subsection of the intermediate section in at least one direction perpendicular to the longitudinal axis is greater than a diameter of a semicircular end surface of the end section, but less than a largest transverse extent of the main section.
2. The electrode as claimed in claim 1 , wherein the cylindrically shaped subsection of the intermediate section directly adjoins the end section.
3. The electrode as claimed in claim 1 , wherein at least the subsection of the intermediate section is circular-cylindrically shaped, and wherein the transverse extent thereof is the diameter of the circular-cylindrical subsection of the intermediate section.
4. The electrode as claimed in claim 1 , wherein the main section is at least partially circular-cylindrically shaped, and wherein the largest transverse extent thereof is the largest diameter of the circular-cylindrical subsection of the intermediate section.
5. The electrode as claimed in claim 3 , wherein the main section is at least partially circular-cylindrically shaped, and wherein the largest transverse extent thereof is the largest diameter of the circular-cylindrical subsection of the intermediate section 4 , wherein the ratio between the diameter of the circular-cylindrical subsection of the intermediate section and the largest diameter of the main section lies in the range of between 0.2 and 0.9.
6. The electrode as claimed in claim 1 , wherein the transition between the intermediate section and the end section is formed at a right angle as seen in a plane containing the longitudinal axis.
7. The electrode as claimed in claim 1 , wherein the main section comprises a structure increasing its surface area.
8. The electrode as claimed in claim 1 , wherein the electrode rod and the electrode head are formed in one piece.
9. The electrode as claimed in claim 1 , wherein the electrode head consists of pure tungsten.
10. The electrode as claimed in claim 1 , having an electrode coil which is arranged at least on a subsection of the main section of the electrode head.
11. The electrode as claimed in claim 10 , wherein the main section is provided with an annular bead which prevents the electrode coil from slipping in the direction toward the circular-cylindrical intermediate section.
12. A high-pressure discharge lamp having a discharge vessel and having two electrodes arranged opposite, wherein at least one of the two electrodes is formed as claimed in claim 1 .
13. A high-pressure discharge lamp having a discharge vessel and having two electrodes arranged opposite, which is configured for alternating-current operation and wherein each of said two electrodes is formed as claimed in claim 1 .
14. The high-pressure discharge lamp as claimed in claim 12 , for video or data projection purposes.
15. The high-pressure discharge lamp as claimed in claim 12 , for endoscopy or effect lighting purposes.
16. The electrode as claimed in claim 3 , wherein the main section is at least partially circular-cylindrically shaped, and wherein the largest transverse extent thereof is the largest diameter of the circular-cylindrical subsection of the intermediate section, wherein the ratio between the diameter of the circular-cylindrical subsection of the intermediate section and the largest diameter of the main section lies in the range of between 0.4 and 0.8.