JPS5838451A - High pressure sodium lamp - Google Patents

Abstract

PURPOSE:To suppress the disperse of the electrode substance at the starting of lamp and to improve the service life characteristic, by encapsulating the neon- argon mixed gas as the starting rare gas in a light emission tube and a glow switch while bringing the pressure dividion ratio between the encapsulating pressure and the argon gas to the specific level. CONSTITUTION:The niobium tubes 4, 5 are encapsulated at both end sections of a light emission tube 1 through the end rings 2, 3 made of alumina while the electrodes 6, 7 are held at the tip section where the shortest distance (d) between said electrodes are shorter than 25mm. while the sodium amalgam 8 having the sodium mol ratio of 78% and the neon-argon mixed gas as the starting rare gas are encapsulated in the light emission tube 1. Here the mixed gas encapsulating pressure is 40-300 Torr while the pressure division ratio of the argon gas against the mixed gas is 5-75%. Similar mixed gas is also encapsulated in the glow switch for applying the starting voltage on said light emission tube.

Description

[Detailed Description of the Invention] Is the present invention lighting? ? -! or solid-state (semiconductor) lighting elements.”
: It is a small, high-pressure thorium lamp that can be started up.

We have already achieved high color rendering using an alumina arc tube with +'1 translucency.
1 high-pressure sodium lamps (150 to 40 OW) have been commercialized.・This lamp has a larger inner diameter than the arc tube of conventional high-pressure thorium lamps, and has a much higher lithium vapor pressure inside the arc tube during lamp operation, making it similar to an incandescent light bulb. It has a warm light color and excellent color rendering properties.

This lamp is 3 to 4 times brighter than a light bulb.
~60f1m/W), and in the arc tube, a neon-argon mixed gas containing approximately 0.5% argon gas is heated at approximately 2° to 30 Torr to enable low voltage starting.
It is an energy-saving, high-brightness rung that more than satisfies today's social demands for energy saving.

Incidentally, recently there has been a growing trend to further promote energy conservation in the field of lighting. Specifically, we replaced low-wattage, low-efficiency incandescent light bulbs with small, compact discharge lamps that take advantage of the characteristics of incandescent electricity.Moreover, we created a simple lighting device that uses a 100-120V commercial power source. The request is to use it in It is extremely difficult to find other discharge lamps that have the potential to meet such strict demands, and in this sense, the high color rendering high pressure thorium lamp is the only discharge lamp available. It can be said that it is a lamp. Under these difficult circumstances, the inventor first proposed a compact, high-color-rendering, high-pressure natriuno lamp with a lamp efficiency of over 40Q m/W and a rated lamp power of 20 to 100W. are doing. This lamp is designed so that the effective lamp current F[ is around 5 Q V, so when the lamp starts,
This is a discharge lamp that can be lit using an inductance ballast with a quotient Jrl power source of 1oO~120V AC.

The IJ Umlamb (compact, high color rendering, high voltage lamp) already satisfies the major requirements of the above-mentioned strict requirements for a compact discharge lamp to replace incandescent bulbs. In order to actually commercialize this lamp and make it widely used in IF rivers, the following two problems must be solved.

One problem is CL, which is a problem with the starting characteristics of the lamp, and the other is a problem with the life characteristics of the lamp.

The present invention was made in view of these problems, and it is an object of the present invention to provide a compact high-pressure sodium lamp that can be reliably started with a quotient 1 old RLI source of 100 to 120 cm and has a long lifespan. be.

The former problem originates from the starting gas (1-IF=1) sealed in the arc tube of the above-mentioned compact, high-color-rendering, high-pressure thorium lamp. In other words, in accordance with the role of the high color rendering high pressure sodium molar ratio of 150 to 400 W, which has already been commercialized in the case of small lamps, with the aim of low voltage starting,
．． Even if a neon-argon mixed gas containing about 5% argon gas is filled in an arc tube at about 25 Torr,
It is impossible to reliably start the lamp with a 100-120V power supply.

Conventionally, this situation has not been improved even if some kind of starting aid means is provided for the arc tube, as has been widely reported. However, solving this problem itself is not very difficult. For example, by using a lighting tube (such as those used in fluorescent lamps or a solid-state semiconductor) lighting element, the lighting tube can be placed in parallel with the lamp and in series with the ballast. When the light tube is shut off, a high pulse voltage of 1 to 2 kV is applied to the lamp, induced by the inductance of the ballast, so the method using the light tube with 〇 ensures reliable starting, compared to other igniters. How to incorporate a bimetallic switch into a ballast and how to install a bimetallic switch into a lamp outer tube.
It is very superior in that it does not overshadow the characteristics of a small lamp compared to other methods. Although the starting of the lamp can be solved, the latter problem regarding lamp life characteristics remains unresolved. In other words, in the case of a small high color rendering high pressure thorium lamp with a low rated lamp power of 2o~100W, the inner diameter of the arc tube is much smaller than that of a 150~400W lamp that has already been commercialized. As a result, the distance between the inner wall of the arc tube and the electrodes has become smaller, and for this reason, the same type of lamp currently used in 150-40oW lamps,
If a starting noble gas is filled in at the same composition and pressure, the electrode material will fly off when starting the lamp.
Written by i.

Therefore, the inventors focused on the mixing ratio and the sealing pressure of the above-mentioned starting rare gas, and conducted experiments and studies on the relationship between these and the lamp life characteristics.

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

FIG. 1 shows a longitudinal section of an alumina arc tube of a 50 W high color rendering high 1F sodium lamp used in the experiment.

In the figure, reference numeral 1 denotes an arc tube made of alumina with an inner diameter φ of 4.7M, and a niobium tube 4.5 is sealed at both ends of the tube through end rings 2 and 3 made of alumina. Electrodes 6 and 7 are held at the tips of the niobium tubes 4 and 5, and the shortest distance α between these electrodes is 10.○.Inside the arc tube 1, the sodium molar ratio is 7
It is filled with 8% storium amalgam 8 and a neon-argon mixed gas as a starting rare gas. 9,10←
A heat retention film made of tantalum is attached to the outer periphery of both widths of the arc tube 1, and when the lamp is operating, heat and light radiated from the inside of the arc tube 1, especially the electrodes 6 and 7, are formed behind the electrodes. 7') It serves to raise the temperature of the coldest point of the arc tube. 1 in this example? When conducting experiments, set the lamp voltage 45v1 lamp power 50v in advance
Under a constant W, when the color temperature changes to 2'500, the color rendering index Ra becomes 80 or more. be.

20 To
Lamps were manufactured with several levels selected in the range from 100 Torr to 500 Torr, and a starting test of the lamp was performed by first setting the lighting tube at 100 Torr.

Figure 2 shows the lighting tube 21 and single choke ballast 22.
The arc tube 1 is assembled into the outer tube 23 using the 1. FIG. 2 is an electrical circuit diagram for a starting experiment of a high-pressure sodium lamp. In this experiment, a current limiting resistor 24 was inserted to measure the breaking current of the lighting tube 21. In this experiment, a power source 25 of 100 AC was applied to the lamp.

As a result of the experiment, the lamp can be started reliably if the pressure of the neon-argon mixed gas is 25%.
The lamp had a pressure of not less than Torr and not more than 300 Torr, and the partial pressure ratio of argon in this mixed gas was not more than 75%. Next, we conducted a rated lighting test for a lamp that can be started reliably in this way, and the lamp life was 9,000 yen.
After the lamp was turned on for a certain period of time, the luminous flux maintenance rate of the lamp (7"1) was measured, and the results shown in the table below were obtained.

[Unit: 2%]

” - As is clear from the table, a lamp that can maintain a practical level (60% or more) of luminous flux even at the end of its life is the one that can maintain the total pressure of the starting rare gas neon-argon mixture sealed in the arc tube 1. is 4°Torr or more, 300T
It can be seen that the partial pressure ratio of argon gas in this mixed gas is in the range of 5% or more and 75% or less. Among these, the reason why the luminous flux maintenance rate at the end of the lamp life exceeds 0% and is not a problem at all in practice is when the sealed pressure of this mixed gas is 50 To
It can be seen that the pressure is in the range of rr or more and 300 Torr or less, and the partial pressure ratio of argon gas in the mixed gas is 10% or more and 75% or less.

The following results were obtained through experiments for a small high-color rendering high-pressure sodium lamp having an arc tube 1 with a shortest distance d between electrodes of 10.0 mm and an inner diameter φ of 4.7 mm. It was confirmed that if the above-mentioned d is 25 or less and the above-mentioned φ is an arc tube of 7jlB or less, the same effect can be obtained not only with the above-mentioned high-pressure sodium thorium lamp but also with general high-pressure sodium thorium lamps. . It goes without saying that a solid-state lighting element may be used instead of the lighting tube.

As explained above, the present invention has an inner diameter in which electrodes are provided at both ends, the shortest distance f between the electrodes is 25 mm or less, and neon-argon mixed gas is sealed as a starting rare gas. It is equipped with an arc tube of 7 mm or less, and a lighting tube or solid-state lighting element for applying a starting power to the arc tube, and the pressure of the neon-argon mixed gas is 40 Torr.
r or more and 300 Torr or less, and the neon-
The partial pressure ratio of argon gas in the argon mixed gas is 6
% or more and 76% or less, therefore, it goes without saying that the lamp can be started reliably with a commercial power source of 100~120V, and the scattering of the electrode material when starting the lamp is greatly reduced. Since this is suppressed, excellent life characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an arc tube of a high-pressure sodium lamp according to the present invention, and FIG. 2 is a lighting circuit diagram of a high-pressure sodium lamp which is an actual Mj example of the present invention. 1... Arc tube, 2, 3 ■... End ring, 4
．． 5-...0 Niobium tube, 6,7... Electrode, 8
II...Sodium amalgam, 9,10. ...
・・Thermal protection film, 21・・Lighting tube, 23・・・・
...Outer tube, 25...Power supply. Name of agent: Toshio Nakao and 1 other person

Claims (1)

[Claims] An arc tube with an inner diameter of 7 r or less, which is provided with electrodes at both ends, and the distance between the electrodes is 26 mm or less, and is filled with a neon-argon mixed gas as a starting rare gas, and this light emitting tube. A lighting tube-sized solid lighting element for applying a starting voltage to the tube is provided, the sealed pressure of the neon-argon mixed gas is 40 Torr or more and 300 Torr or less, and argon gas accounts for the neon-argon mixed gas. A high-pressure sodium lamp characterized in that the partial pressure ratio of is in the range of 5% or more and 75% or less.