Quartz glass lamp and method for forming a quartz glass lamp
A method is provided for formation of a glass to metal seal at one end of a quartz lamp tube, as part of the process of manufacturing a complete lamp tube. The method involves a direct sealing of the tube of quartz glass with a seal material surrounding an electrode or its electrical feed through. The seal material may be in the form of a bead having a generally elliptical or spherical shape.
1. A method of forming a quartz glass lamp containing electrodes within a tube of quartz glass, the method comprising:
(a) surrounding the electrodes or an electrical feed through of the electrodes with a bead of sealing glass;
(b) inserting the electrode or the electrical feed through of the electrode into an annulus of the quartz glass tube, thereby directly contacting the bead of sealing glass to the quartz glass tube;
(c) heating the quartz glass tube and bead of sealing glass to allow the bead of sealing glass to wet on and fuse with the quartz glass tube; and
(d) applying, while the bead of sealing glass is molten, a positive pressure within the quartz glass tube to form a smooth internal radius of the bead of sealing glass between the electrode or the electrical feed through and the quartz glass tube.
2. The method of claim 1 , wherein the sealing glass has a coefficient of expansion between that of the electrode or the electrical feed through and that of the quartz glass.
3. The method of claim 1 , wherein prior to step (b), the bead of sealing glass is heated to a soft state and rotated on a lathe.
4. The method of claim 1 , wherein the bead of sealing glass in step (a) is provided with a size larger than an internal diameter of the quartz glass tube but less than or equal to an external diameter of the quartz glass tube.
5. The method of claim 1 , wherein prior to step (a), the annulus of the quartz glass tube is pre-formed to a predetermined dimension.
6. The method of claim 1 , wherein the annulus of the quartz glass tube is molten during step (b).
7. The method of claim 1 , wherein the quartz glass tube is provided for a laser or flash lamp.
8. The method according to claim 1 , wherein the sealing step is carried out using automatic equipment.