Finite-Element Stress Analysis and Strength Evaluation of Super High Pressure Mercury Lamp Bulbs under Internal Pressure

Abstract

Super high pressure mercury discharge lamps have been used as UV light sources for photolithography, such as patterning LCDs, PCBs and semiconductors. The bulbs of the lamps are generally made of silica glass. This study evaluates optimal shapes for various lamp bulbs under internal pressure employing the Finite Element Method (FEM). As the result, the optimal shape of the bulb was obtained and the relationship between the rupture stress and the bulb wall thickness t was clarified. The optimal shape of the bulb obtained is 0.7 ≤ D/L ≤ 0.85, where L is the total length of the bulb and D is the diameter. Static water pressure-tests were conducted in order to verify the numerical results. It was found that tendency between the numerical results and experiments were in fairly good agreement.