High-Pressure Discharge Lamp Sealing Wedge Edge Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-pressure mercury discharge lamps used in projection-type image displays face breakage issues due to stress concentration caused by gaps between metal foils and electrodes during the sealing process, which cannot be adequately addressed by existing methods such as forming curved edges or chemical etching.
Innovation Solution
A method for manufacturing high-pressure discharge lamps where the edge of the metal foil is cut to form a wedge shape, with a specific relationship between the buried length of the electrode and the glass tube diameter, and the metal foil is sealed using a heat-melt process to minimize contact and prevent gap formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the buried length of the electrode is decreased to increase brightness, then the lamp brightness is improved, but gaps are generated between the metal foil and electrode during sealing, causing stress concentration and breakage
Solution Approach 1:
The edge portion of the metal foil is formed with a roundly curved shape convex toward the outside before the sealing process. This preliminary structural preparation prevents stress concentration at the edge during subsequent sealing and operation, allowing the electrode buried length to be minimized for brightness while maintaining reliability through the pre-formed curved edge structure
Solution Approach 2:
The edge portion of the metal foil is formed with a roundly curved shape instead of a sharp edge. This curvature distributes stress evenly around the edge, preventing stress concentration and gap formation during sealing, thereby maintaining both high brightness (from minimal electrode burial) and high reliability (from stress distribution)
2Reliability
If the edge portion of the metal foil is formed with a roundly curved shape to prevent stress concentration, then breakage resistance is improved, but gaps still form during sealing process, causing stress concentration
Solution Approach 1:
The relationship between the buried length of the electrode and the inner diameter of the glass tube is controlled within a specific range (0.8 ≤ buried length/inner diameter < 1.5). This parameter control ensures that the glass tube can be properly shrunk and sealed without generating gaps, while maintaining the roundly curved edge shape for stress distribution, thereby achieving both good sealing quality and breakage resistance
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 approach effectively suppresses the generation of gaps and stress concentrations, enhancing the lamp's brightness and preventing breakage during its operational life span.
Implementation Method 1
melting by heat and shrinking the glass tube for sealing the metal foil and the electrode
Implementation Method 2
melting by heat and shrinking the glass tube for sealing the metal foil and the electrode
Data Source
AI summary
The present invention is directed to a method for manufacturing a high-pressure discharge lamp including: a spherical portion forming a light-emitting portion (1a); sealing portions that are connected with both ends of the spherical portion; an electrode (2a) that is sealed to each of the sealing portions; and a metal foil (3a) that is connected with a rear end of each electrode. A vessel provided with a cylindrical glass tube (8) on both ends of the spherical portion is used, a connection structure of the metal foil and the electrode are disposed in the glass tube such that a front end of the electrode is positioned in the spherical portion, and the glass tube is melted by heat and shrunk for sealing the metal foil and the electrode so as to form the sealing portion. An inner diameter φ of the glass tube before the heat-melt processing and a distance L from an edge of the metal foil to the internal space of the spherical portion are set to satisfy a relationship of L/φ≧1.35, a corner of an edge portion of the metal foil on a side of the connection with the electrode is cut so as to form a wedge shape (7a), and subsequently the sealing step is performed. Thereby, it can suppress the generation of the breakage during the lighting life span, which is caused by a gap generated from the metal foil to an axis of the electrode during the sealing processing of the high-pressure discharge lamp having a high brightness property.