High-pressure discharge lamp with improved intensity distribution
A high-pressure discharge lamp having a discharge vessel with a central part that bulges out and which defines a lamp axis with a sealing part being attached to each end of the discharge vessel. The shaft of in each case one electrode, comprising a head and a shaft, is sealed in the sealing part, and a capillary tube closely surrounding the shaft of the electrode is between the central part of the discharge vessel and the sealing part. A tubular neck is integrally formed as a component of the discharge vessel between the central part and the capillary tube, and is separated from the shaft.
1. A high-pressure discharge lamp having a discharge vessel with a central part that bulges out and which defines a lamp axis with a sealing part being attached to each end of the discharge vessel, with the shaft of in each case one electrode, comprising a head and a shaft, being sealed in the sealing part, and with a capillary tube for supporting the electrode by closely surrounding the shaft of the electrode between the central part of the discharge vessel and the sealing part, wherein a tubular neck is integrally formed as a component of the discharge vessel at the each end of the discharge vessel between the central part and the capillary tube, and is separated from the shaft,
wherein the lamp is a direct-current lamp, having a cathode and an anode as electrodes, the cathode being smaller than the anode, and
wherein the external diameter of the tubular neck associated with the anode is approximately 1.2 to 1.6 times as large as the external diameter of the tubular neck associated with the cathode.
2. The high-pressure discharge lamp as claimed in claim 1 , wherein, on the discharge side, the head of the electrode has a section which tapers conically and whose extension defines an electrode shadow, with at least the majority of the neck being arranged in the area of the shadow.
3. The high-pressure discharge lamp as claimed in claim 1 , wherein a pump connecting stub is attached to one of the two necks.
4. The high-pressure discharge lamp as claimed in claim 1 , wherein the external diameter of the neck associated with the cathode is about 3 to 6 times as large as the diameter of the shaft of the cathode.
5. The high-pressure discharge lamp as claimed in claim 1 , wherein the external diameter of the neck associated with the anode is approximately 4 to 7 times as large as the diameter of the shaft of the anode.
6. The high-pressure discharge lamp as claimed in claim 1 , wherein a pump connecting stub is attached to the neck which is associated with the anode.
7. The high-pressure discharge lamp as claimed in claim 2 , wherein the neck is arranged completely in the area of the shadow.