Research progress on mercury-free metal halide lamps

Another type of material currently proposed to replace mercury is metal halides such as ScI2, ZnI4, etc., which can be used to make mercury-free metal halide lamps operate at 40-70 volts, but such metal halide lamps The increase in lamp voltage drop is not due to the large number of elastic collisions of electrons at high pressure, but is caused by the large amount of free Br or I atoms in the arc region and nearby metal halide molecules during discharge. Atoms are easily adsorbed by electrons to form negative ions, and the space charge of a large number of negative ions causes the potential gradient of the space to rise to form a higher lamp voltage drop. In such a state, the number of electrons participating in the ionization excitation is reduced, while the energy is large, the ionization excitation efficiency is lowered, the light efficiency is low, and the arc curvature is increased. The presence of a large amount of free halogen atoms will also corrode the components in the lamp to reduce lamp life, so it is not a good idea to completely replace the mercury with a metal halide.

Development of Snowlight Mercury-Free Metal Halide Lamps Snowlight's development of mercury-free metal halide lamps has taken a different approach than the aforementioned patents. The alternative to mercury in Shelley is the elemental form of selenium (Se). Selenium is a necessary trace element in the human body. It is said that if you add 200ugse per person per day, you can prevent cancer. Too much is poisonous. Se has an valence of ±2,4,6, and an atomic weight of 78.96. It has six non-radioactive isotopes and is 34 in the periodic table. It belongs to Group 6, and is a semiconductor material that is stable at room temperature. Se The ionization potential is 9.75V (slightly lower than Hg 10.4V), the resonant potential is 5.95V and 6,30V (mercury is 4.67 and 6.70V); the corresponding resonant radiation lines are 207.4nm and 196nm (Hg is 253.7nm, 185nm), all these parameters are not far from Hg, more importantly, Se does not react with tungsten or molybdenum, and the boiling temperature of Se is only 688~(2, although it is higher than 356.6~C of mercury but much more than The metal halide used in the lamp is low, much lower than zinc, and it is easy to fully vaporize at the normal operating temperature of the metal halide arc tube to form a sufficiently high Se vapor pressure to ensure the buffer vapor density close to the mercury-filled lamp and the main Operating parameters, such as this lamp pressure drop of about 50 ~ 70V, light efficiency of about 70-80Lm / w.

Se usually appears in the form of Se2 and Se8. In the excited state, polyatomic molecules such as S, \S: ... may appear. Therefore, the excitation spectrum of various selenium molecules will appear under the condition of Se-mercury (molecular spectrum and The superposition of atomic spectra, and thus the emergence of a rich continuous spectrum and infrared spectrum, the reduction of light efficiency after the use of selenium instead of mercury is caused by rich red and infrared radiation. The appearance of a large number of continuous spectra significantly improves the color rendering of the lamp.

Snowlight Optoelectronics has developed two types of mercury-free metal halide lamps, one of which is a 35W low-power selenium-metal halide lamp filled with high-pressure helium. The results of different color temperature metal halide lamps show the color temperature and efficacy after using seleno mercury. Both the lamp pressure drop and the lamp drop are slightly lower, while the color rendering index and the red ratio are both significantly increased.

Another type of mercury-free metal halide lamp developed by Shellecht is a low-pressure argon-loaded selenium-metal halide lamp for the medium-power 250W stage, which is similar to the 35V/helium selenium metal halide lamp. A trace of mercury traces remained in the spectrum of such mercury-free lamps developed because of the addition of trace amounts of HgBr to maintain a good halo-tungsten cycle. After finding pure HgBr2, it can be completely used to replace HgBr to make an absolute mercury-free lamp. Whether the selenium xenon metal halide for the car or the selenium argon metal halide lamp for the stage is similar to the structure of the mercury-filled lamp (Figl, Pig2).

Snowlight Optoelectronics has also developed an elemental mercury-free metal halide lamp that replaces Hg with compound Hgse [7]. The parameters of this lamp range from mercury-filled metal halide lamps to various metal halide lamps with seleno-mercury. Between nig5, a 250W phase metal halide lamp with compound Hgse replaced by element Hg is shown in nig5. Since Hgse is decomposed into Hg and Se atoms in the high temperature arc region, mercury is replaced by Hgse. Significant Hg appears in mercury-free lamps; the spectrum of selenium also appears in the spectrum.

The development of mercury-free metal halide lamps has been on the agenda. Shellett has taken the lead in exploring this field. Our solutions have obvious realities and advantages in the various mercury-free lamp solutions that have emerged. In this scheme, mercury is used to replace mercury. It is a non-toxic, chemically stable selenium. This material does not react with any material in the lamp. The vaporization temperature is low. After vaporization, it is neutral or monoatomic. Selenium vapor can be a good buffer gas and can guarantee long-term stable operation.


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