As an important gas discharge light source, high-pressure mercury lamps are widely used in industrial lighting, medical equipment, and UV curing. The quality of their forming process directly impacts the performance and lifespan of the lamps, making in-depth research into their manufacturing process crucial.
The core structure of a high-pressure mercury lamp consists of a quartz glass tube, an electrode system, and a mercury vapor filler. The forming process begins with the preparation of the glass tube. High-purity quartz sand is melted at high temperatures and then drawn into a tube to ensure a uniform and heat-resistant tube wall. Subsequently, tungsten electrodes are precision-machined at each end of the glass tube, filled with a small amount of argon gas as a starting medium, and a certain amount of liquid mercury is sealed.
The key process step is sealing the electrodes to the glass tube. Due to the extremely low coefficient of expansion of quartz glass, a molybdenum sheet transition sealing technique is employed. After welding the molybdenum sheet to the tungsten electrode, a high-temperature flame is used to fuse the molybdenum sheet to the quartz tube. This process requires strict temperature and time control to prevent glass cracking or electrode displacement. After sealing, the lamp is evacuated to remove any remaining air. It is then filled with a precisely balanced mixture of argon and mercury vapor to ensure discharge stability.
Finally, the lamp undergoes a burn-in test, where it is illuminated at rated voltage for an extended period to allow a stable emission layer to form on the internal electrode surface and to expel impurities generated by the initial discharge. This process significantly improves the luminous efficiency and lifespan of the high-pressure mercury lamp.
In summary, the molding process for high-pressure mercury lamps combines materials science, vacuum technology, and precision manufacturing techniques. Each step requires rigorous control to ensure the optical performance and reliability of the final product. While high-pressure mercury lamps face replacement pressure with the rise of LED technology, they remain irreplaceable in certain applications, and optimizing their molding process remains a key area of research for the industry.
