Electrode Grooves for Stress Distribution in High Pressure Lamps
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Solution Overview
Problem
High pressure discharge lamps face breakage and bending issues due to stress concentration at the ends of grooves on the electrode axis, caused by thermal expansion differences between tungsten electrodes and silica glass, especially when the electrode diameter is small.
Innovation Solution
Forming two or more grooves on the electrode axis in the axis direction, with the ends of these grooves not aligned on the metallic foil side, and leaving a remaining portion without grooves for stress distribution and easier welding, using techniques like laser processing or electric spark machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two or more grooves are formed on the electrode axis to prevent sealing portion breakage, then the sealing portion reliability is improved, but stress concentration occurs at the groove ends causing electrode axis bending or breakage
Solution Approach 1:
The groove depths are made asymmetric along the electrode axis, with the first groove having a different depth than the second groove. This asymmetric configuration prevents stress concentration at aligned groove ends while maintaining the stress-distributing effect on the sealing portion, thereby resolving the contradiction between sealing reliability and electrode strength
Solution Approach 2:
The electrode axis surface is segmented into multiple grooves with different depths, creating distinct stress relief zones. The segmentation prevents continuous stress pathways that would otherwise lead to fracture, while still providing adequate stress distribution to the sealing portion
2Volume of moving object
If the electrode axis diameter is reduced to achieve compact lamp design, then the lamp size is reduced, but the electrode axis becomes more susceptible to bending and breakage
Solution Approach 1:
The groove structure provides localized stress management at critical regions of the electrode axis. By concentrating stress relief features where needed rather than uniformly thickening the entire electrode, the design maintains compact dimensions while preventing fracture in vulnerable areas
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces stress concentration and prevents bending or breakage of the electrode axis, enhancing the structural integrity and reliability of high pressure discharge lamps by distributing stress evenly and facilitating secure welding.
Implementation Method 1
the sealing portion of the arc tube often breaks and/or is damaged due to difference in the thermal expansion coefficients
Implementation Method 2
using techniques like laser processing or electric spark machining
Implementation Method 3
using techniques like laser processing or electric spark machining
Implementation Method 4
the base portion of an electrode axis is joined to a metallic foil buried in a sealing portion
Data Source
AI summary
The present invention relates to a high pressure discharge lamp that includes a pair of electrodes, which face each other in an electric discharge space. Further, an electrode axis of one of the electrodes is joined to a metallic foil in a sealing portion, and two or more grooves are formed in an axis direction on a portion corresponding to the sealing portion on the electrode axis. Furthermore, a remaining portion that lacks grooves is left on the electrode axis in a metallic foil side thereof, and the metallic foil side ends of the grooves are not aligned with each other in the axis direction thereof.