Tungsten electrode, preparation method thereof and high-pressure discharge lamp adopting tungsten electrode

Abstract

The invention discloses a preparation method of a tungsten electrode, the tungsten electrode prepared by the method and a high-pressure discharge lamp adopting the tungsten electrode. The preparationmethod comprises the following steps: S1) preparing the tungsten electrode in shape; S2) performing acid etching treatment on the tungsten electrode; S3) performing vacuum high-temperature sintering to roughen crystals; and S4) carrying out secondary acid etching treatment on the surface, so that the surface is similar to the shape of the surface of the polygon prism, peak valley concave-convex parts are formed on the surface, and the height difference of the concave-convex parts is 5-25 [mu]m. When the tungsten electrode (222) prepared by implementing the method is used for the high-pressuredischarge lamp, the phenomena of quartz glass cracks (131) and high-pressure discharge lamp breakage caused by the difference of thermal expansion and cold contraction coefficients between the tungsten electrode (222) and the quartz glass of a side tube part (11) of a discharge container (1) in the manufacturing process or the lamp turning-on and turning-off process of the high-pressure dischargelamp can be restrained, and the service life of the high-pressure discharge lamp is prolonged.

Description

technical field [0001] The invention relates to the optoelectronic field, in particular to a preparation method of a tungsten electrode or a tungsten electrode mainly composed of tungsten, and the tungsten electrode prepared by the preparation method. The invention also relates to a high-pressure discharge lamp using the above-mentioned tungsten electrode. Background technique [0002] There are high-pressure discharge lamps that are widely required in optical equipment such as projectors and exposure machines. Two tungsten electrodes with tungsten as the main component are placed opposite to each other in a quartz discharge vessel. One end of the electrodes is buried in quartz glass, and The metal foil (such as molybdenum foil) with an expansion coefficient close to that of quartz is connected to the external power supply wire, and the metal foil (such as molybdenum foil) is fused and sealed with quartz glass by an external heat source to form a relatively sealed quartz disc...

AI Technical Summary

Problems solved by technology

[0012] The first problem of the high-pressure discharge lamps using methods 1 and 2 in the prior art is that the large amount of heat energy accumulated by the electrodes during the manufacturing process or lighting process cannot be released by conduction in time due to the reduced contact area between the electrodes and the quartz glass. Small contact surfaces or end faces / corners as described in a)b)c) above are prone to stress concentration sharply, leading to bulb rupture

[0013] The second problem that exists in the high-pressure discharge lamps prepared by methods 1 and 2 of the prior art is that after being isolated by the intermediate medium or after the groove is processed, an electric potential is easily formed between the electrode or the groove valley of the electrode groove and the quartz glass. Difference

When the potential difference is loaded with high voltage (such as 3KV) at the moment of lighting, it is easy to increase sharply at the root of the discharge vessel, forming a discharge phenomenon from the electrode to the quartz glass near the root of the discharge vessel, causing SiO2, which is the main component of the quartz glass, to decompose into Si and O. And enter the quartz container and combine with other substances to cause the bulb to turn black and have a short life

[0014] The third problem of high-pressure discharge lamps using methods 1 and 2 of the prior art is that, from an economic point of view, the manufacturing process of high-pressure discharge lamps using methods 1 and 2 of the prior art is obviously complicated and expensive

[0015] As for the high-pressure discharge lamp of method 3 in the prior art, the first defect is that it is usually installed after the assembly and processing of the discharge lamp is basically completed, and it cannot prevent cracks in the quartz glass during the manufacturing process (such as quartz hot-melt fixed electrodes); the defect Second, the outer layer of quartz glass coated with thermal insulation film or thermal insulation coil can only delay the cooling effect in low temperature areas (such as below 200 ℃), and it is almost impossible for the quartz glass near the root of the quartz discharge vessel (the lighting temperature inside the quartz glass is above 600 ℃). Can affect the role of quartz glass crack formation

In other words, it has no practical effect on preventing crack damage

Images