JPS6343802Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to high-pressure metal vapor discharge lamps such as high-pressure sodium lamps, and in particular, uses translucent alumina as an arc tube, and fills mercury, sodium, etc. in the arc tube with starting aid gas. This relates to a nearby conductor for reducing the starting voltage in high-pressure sodium lamps filled with Xe, Ne, Ar, etc.

The gas pressure of the rare gas sealed in the arc tube of a high-pressure sodium lamp is generally about 20 to 25 Torr. The proximal conductor in this case is constructed by winding a heat-resistant metal wire multiple times around the outer periphery of the surface of the arc tube, and electrically connecting it so that a counter electrode potential is applied. In this way, the starting voltage of the high pressure sodium lamp is reduced.

Incidentally, recently, in order to further improve the luminous efficiency of high-pressure sodium lamps, research and development efforts have been actively conducted to increase the pressure of the rare gas sealed in the lamps to be much higher than that conventionally used. This type of lamp has a higher starting voltage than conventional types of lamps with lower noble gas fill pressures. When a nearby conductor similar to conventional lamps was installed in this type of lamp, the starting voltage was reduced, but it was found that the drop was not sufficient. Therefore, when a strip-shaped adjacent conductor extending in the longitudinal direction of the arc tube was installed and an electrical connection was made so that a counter electrode potential was applied, the starting voltage was significantly reduced. This experimental fact suggests that there is an optimal installation form for the adjacent conductor depending on the sealing pressure of the rare gas.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a high pressure metal vapor discharge lamp, such as a high pressure sodium lamp, which has an optimal proximal conductor shape depending on the fill pressure of rare gas.

In order to achieve the above purpose, in this invention,
We focused on the relationship between the state of discharge due to differences in the filling pressure when the discharge lamp starts up and the shape of the adjacent conductor, and investigated the case where a thick glow discharge occurs throughout the arc tube (occurs when the filling pressure of rare gas is low). ), install a nearby conductor so that it wraps around the arc tube multiple times, and if a narrow glow discharge occurs in the arc tube (occurs when the sealing pressure of rare gas is high), install a conductor around the arc tube with a single wrap.
Alternatively, the starting voltage can be effectively lowered by installing a nearby conductor so as to extend linearly in the pipe length direction. Of course, in both cases, it is necessary to connect the adjacent conductor so that a counter electrode potential is applied thereto.

According to the characteristic configuration of the present invention, it is possible to give an optimal shape to the adjacent conductor depending on the pressure of the enclosed rare gas, and it is possible to reliably lower the starting voltage.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 and 2 show the shape of the adjacent conductor of a high-pressure sodium lamp according to the present invention. In FIG. 1, electrodes 2 and 3 are sealed at both ends of an arc tube 1 made of translucent alumina. Appropriate amounts of sodium and mercury are each filled in the arc tube 1, and approximately Xe gas is filled as a starting aid gas.
75Torr is enclosed. As shown in the figure, a proximal conductor 4 made of a heat-resistant metal wire is installed on the outer surface of the arc tube 1. This proximal conductor 4 is connected so as to bring the potential to be applied to the electrode 3 close to the electrode 2, and a neon transformer (not shown) is connected between both ends 5 and 6 of the proximal conductor 4. here,
When a voltage is applied to the primary side of the neon transformer, a high voltage is generated on the secondary side, that is, between the terminals 5 and 6, and a glow discharge 7 as shown is generated. The generation form of glow discharge 7 at the time of startup is enclosed.
It was found through various experiments that it changes depending on the sealing pressure of Xe gas. In other words, when the Xe gas filling pressure is less than 100 Torr, regardless of the filling pressure, there is a thick layer between the electrodes 2 and 3 in the arc tube 1 that spreads all the way into the arc tube 1, as shown in FIG. A glow discharge 7 occurs. Then, when the pressure of the Xe gas increases to 100 Torr or more, the glow discharge 7
becomes thinner and becomes more than about 150 Torr, as shown in FIG. 2, an extremely thin glow discharge 8 will be generated between the electrodes 2 and 3. In the case of FIG. 2, since the arc tube 1 is lit in a horizontal state, the thin glow discharge 8 is formed so as to stick to the upper inner wall of the arc tube 1.

This phenomenon in which the generation form of glow discharge at startup differs depending on the pressure of the enclosed rare gas is not limited to Xe gas, but the same tendency was observed for other rare gases as well. However, the only difference is the pressure of the filled gas when the form of glow discharge changes. This means that the lighting condition, i.e. horizontal lighting,
No difference was observed in the vertical lighting position or the lighting position in between. However, when the sealing pressure at which the thin glow discharge 8 was generated was high, the degree to which the glow discharge 8 approached the inner wall of the arc tube changed depending on the lighting posture.

Furthermore, various experimental studies were conducted regarding the relationship between the above-mentioned form of glow discharge generation and the shape of the adjacent conductor, and the following findings were found. That is, when the glow discharge 7 occurs throughout the arc tube 1 as shown in FIG. 1, the more the number of turns of the adjacent conductor 4 is increased, the lower the starting voltage becomes. On the other hand, when a thin glow discharge 8 is generated within the arc tube 1 as shown in FIG. 2, the adjacent conductor 4 as shown in FIG. Conversely, the starting voltage will increase. As shown in FIG. 2, a strip-shaped adjacent conductor 9 extends linearly in the longitudinal direction of the arc tube 1.
The degree of decrease in starting voltage was greatest when the adjacent conductor 9 was installed, or when the adjacent conductor 9 was installed so that the arc tube 1 was wound with less than a single turn (not shown).

In the case of winding installation, compared to straight installation, adhesion to the arc tube 1 can be easily obtained by simply winding it, which has the side effect of dramatically improving workability when installing adjacent conductors. can get.

From the above results, when the filled gas pressure is low and glow is generated throughout the arc tube, the adjacent conductor is wound multiple times, and when the filled gas pressure is high and the glow is thin, the adjacent conductor is wound 0 to 1 times.

That is, as the sealing pressure becomes higher, the discharge starting voltage becomes higher, so that the light cannot be lit only by the adjacent conductor, and a pulse generator is required. However, the pulse voltage
If the voltage exceeds 3,500 to 4,000V, accidents are likely to occur due to short circuits in the lamp socket or ballast, so the lamp must be lit below this level. This condition can be satisfied by the number of windings of the adjacent conductor.

The relationship between the form of glow discharge generation and the shape of the adjacent conductor was not limited to Xe gas, but also had almost the same tendency for other rare gases. of course,
This relationship was not affected by the lighting position.

Note that the proximal conductor may be provided in close contact with the arc tube, or may be provided in close proximity to the arc tube.

As described above, since the high-pressure metal vapor discharge lamp according to the present invention can reliably lower its starting voltage, it is an extremely reliable discharge lamp that does not cause accidents such as non-lighting.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing the structure of the adjacent conductor of the high-pressure metal vapor discharge lamp according to the present invention. 1... Arc tube, 2, 3... Electrode, 4, 9... Proximity conductor, 7, 8... Glow discharge.

Claims (1)

[Scope of utility model registration request] In a high-pressure metal vapor discharge lamp having an arc tube in which electrodes are sealed at both ends, an appropriate amount of sodium, mercury, or a rare gas is filled in and a proximal conductor is provided in contact with or in close proximity to the surface, the above-mentioned discharge lamp If the rare gas is xenon gas and its sealing pressure is at least 150 Torr so that a narrow glow discharge occurs in the arc tube when the lamp is started, the adjacent conductor should be wound around the arc tube in a single turn or less. 1. A high-pressure metal vapor discharge lamp, characterized in that the lamp is provided with a counter electrode potential applied to the adjacent conductor.