JPH0465491B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a high-pressure sodium lamp device in which the high-pressure sodium lamp is started by a starter tube or a solid state lighting element. High color rendering high pressure sodium lamps (150-400W) using translucent alumina arc tubes have already been commercialized. This lamp has a larger inner diameter than the arc tube of conventional high-pressure sodium lamps, and has a much higher sodium vapor pressure inside the arc tube during lamp operation, producing a warm light color similar to that of an incandescent light bulb. It has excellent color rendering properties. Furthermore, this lamp is 3-4 times brighter than a light bulb (40
~60 lm/w), and in order to enable low voltage starting, a neon-argon mixed gas containing approximately 0.5% argon gas is injected into the arc tube.
It can be said that it is an energy-saving high-intensity lamp that is encapsulated with 30 Torr and more than meets the current social demands for energy conservation. Incidentally, recently, there has been a growing trend to further promote energy conservation in the field of lighting. Specifically, I would like to replace low-wattage, low-efficiency incandescent light bulbs with small, compact discharge lamps while retaining the characteristics of light bulbs, and if possible, I would like to replace them with 100
The request was to use a simple lighting device with ~120V commercial power supply. It is extremely difficult to develop other discharge lamps that have the potential to meet such strict demands, and the high color rendering high pressure sodium lamp mentioned above is the only discharge lamp in this sense. It can be said that it is a lamp. Under these circumstances, the applicant must first apply for 20
Under the rated lamp power of ~100W, the lamp efficiency is
We are proposing a compact high-pressure sodium lamp with high color rendering performance and high efficiency exceeding 40 lm/w. This lamp is designed with an effective lamp voltage of around 50V, so
Once the Itsutan lamp is started, it is a discharge lamp that can be lit using an inductance ballast using AC 100-120V commercial power. In this way, this compact, high-color-rendering, high-pressure sodium lamp already satisfies the major requirements for a compact discharge lamp to replace incandescent bulbs, as mentioned above. In order to commercialize the product and have it widely used in the market, the following two problems must be solved. One 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 has been made in view of these problems, and it is an object of the present invention to provide a compact high-pressure sodium lamp device that can be reliably started with a commercial power supply of 100 to 120 V and has excellent life characteristics. The former problem originates from the starting rare gas sealed in the arc tube of the above-mentioned small high color rendering high pressure sodium lamp. In other words, in the case of this small lamp, a neon-argon mixed gas containing about 0.5% argon gas is used, aiming at low voltage starting, in accordance with the design of 150 to 400 W high color rendering high pressure sodium lamps that have already been commercialized. Even if approximately 25 Torr of the lamp was sealed in the arc tube, it was no longer possible to reliably start the lamp with a commercial power supply of 100 to 120 V. This situation could not be improved even if some kind of starting aid means was provided for the arc tube, as has been widely used in the past. However, solving this problem itself is not very difficult. For example, using lighting tubes or solid state (semiconductor) lighting elements such as those used in fluorescent lamps. If this lighting tube is placed in parallel with the lamp and in series with the ballast, a high pulse voltage of 1 to 2 kV induced in the ballast's inductance will be applied to the lamp when the lighting tube is shut off. Starts reliably. This method of using a lighting tube is superior to other methods of incorporating an igniter into a ballast or of mounting a bimetallic switch in the lamp outer tube in that it does not impair the characteristics of a compact lamp. Although the starting problem of the lamp can be solved in this way, the latter problem regarding lamp life characteristics remains unsolved. In other words, in the case of a small high-color rendering high-pressure sodium lamp with a low rated lamp power of 20 to 100 W as in the previous application, the inner diameter of the arc tube is 150 to 100 W, which is already commercially available.
It is much smaller than that of a 400W lamp, and the distance between the inner wall of the arc tube and the electrode is also smaller, making it suitable for starting with the same type, composition ratio, and fill pressure as currently used in 150-400W lamps. If a rare gas is enclosed, it becomes difficult to transition from glow discharge to arc discharge when starting the lamp, and the electrode material becomes more likely to scatter. As a result, the luminous flux decreases significantly during its life. Therefore, the inventors focused on the mixing ratio and the sealing pressure of the starting rare gas, and conducted experiments and studies on the relationship between these and lamp life characteristics. Hereinafter, the present invention will be explained in detail with reference to the drawings. Figure 1 shows a longitudinal section of the alumina arc tube of the 50W high color rendering high pressure sodium lamp used in the experiment. In the figure, reference numeral 1 denotes an arc tube made of alumina and having an inner diameter φ of 4.7 mm, and niobium tubes 4 and 5 are sealed to 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 d between these electrodes is 10.0 mm. Luminous tube 1
Inside, a sodium amalgam 8 with a sodium molar ratio of 78% and a neon-krypton mixed gas as a starting rare gas are sealed. 9 and 10 are thermal protection films made of tantalum, which are attached to the outer periphery of both ends of the arc tube 1, and protect the arc tube 1 during lamp operation.
The heat and light radiated from the interior of the arc tube, particularly the electrodes 6 and 7, are confined in the coldest point of the arc tube formed behind the electrodes, thereby increasing the temperature of this coldest point. When conducting experiments in this example, the color temperature was
2500K, with an average color rendering index Ra of 80 or higher,
The lengths of the thermal protection films 9 and 10 in the longitudinal direction of the arc tube 1 are adjusted in advance. A lamp was manufactured by filling the arc tube 1 shown in Fig. 1 described above with neon-krypton mixed gas at various mixing ratios as a starting rare gas, selected at several levels in the range of 20 Torr to 500 Torr, and first lit. A lamp starting test was conducted using the tube. Figure 2 shows an electrical circuit diagram for a high-pressure sodium lamp starting experiment.
A lighting tube 22 is connected in parallel with the high-pressure sodium lamp in which the lighting tube 22 is incorporated, and a current limiting resistor 23 is connected in series with the lighting tube 22 to limit the current flowing therein. The AC 100V power supply 25 and the lamp are applied through the power source 25 and the lamp. As a result of this experiment, the lamp can be reliably started if the pressure of the neon-krypton mixed gas is 20 Torr or more and 250 Torr or less, and the krypton partial pressure ratio of the mixed gas is 50% or less. It was hot. Next, we conducted a rated lighting test on a lamp that can be started reliably in this way, and measured the luminous flux maintenance rate of the lamp after 9,000 hours of operation, which is the lamp's lifespan, and the results shown in the table below were obtained.

[Table] 〓Unit:%〓
As is clear from the table above, a lamp that can maintain a practical level (60% or more) of luminous flux even at the end of its life will require that the total pressure of the starting rare gas neon-krypton mixture sealed in the arc tube 1 be
It can be seen that the pressure is 30 Torr or more and 250 Torr or less, and the partial pressure ratio of krypton gas in the mixed gas is in the range of 3% or more and 50% or less.
Among these, the luminous flux maintenance rate at the end of the lamp life is
If it exceeds 70% and is not a problem at all in practice, the pressure of the same mixed gas is 40 Torr or higher,
It is in the range of 250 Torr or less, and the partial pressure ratio of krypton gas in this mixed gas is 5% or more,
It can be seen that it is less than 50%. The above results were obtained through experiments on a small high-color-rendering high-pressure sodium lamp having an arc tube 1 with a minimum distance d between electrodes of 10.0 mm and an inner diameter φ of 4.7 mm. It has been confirmed that, as long as the above-mentioned arc tube has a diameter of 7 mm or less, the same effect can be obtained not only in the above-mentioned high color rendering high pressure sodium lamp but also in a general high pressure sodium lamp. It goes without saying that a solid-state lighting element may be used instead of the lighting tube. As explained above, according to the present invention, a high-pressure sodium lamp device includes a high-pressure sodium lamp connected to an AC power source via a ballast, and a lighting tube or a solid-state lighting element connected to both ends of the high-pressure sodium lamp. The high-pressure sodium lamp is a light-emitting lamp with an inner diameter of 7 mm or less, which is provided with electrodes at both ends, the shortest distance between the electrodes is 25 mm or less, and is filled with neon-krypton mixed gas as a starting rare gas. With a tube inside the outer tube, 100-120V
A 20-100W high-pressure sodium lamp that is lit with an AC power supply voltage of
and the partial pressure ratio of krypton gas in the neon-krypton mixed gas is in the range of 3% or more and 50% or less. Because the scattering of
Excellent life characteristics can be obtained. moreover,
By providing the lighting tube or solid-state lighting element outside the high-pressure sodium lamp, the present invention prevents the lighting tube or solid-state lighting element from deteriorating due to heat from the arc tube. Starting performance can be stably maintained over a long period of time, and lamp starting can be stabilized. Furthermore, when a neon-krypton mixed gas is used as the starting rare gas, heat conduction loss is reduced compared to when a neon-argon mixed gas is used, which is advantageous in terms of lamp efficiency.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an arc tube of a high-pressure sodium lamp device according to the present invention, and FIG. 2 is a lighting circuit diagram of a high-pressure sodium lamp device according to an embodiment of the present invention. 1... Arc tube, 2, 3... End ring, 4,
5... Niobium tube, 6, 7... Electrode, 8... Sodium amalgam, 9, 10... Heat protection film, 21...
...outer tube, 22...lighting tube, 25...power supply.

Claims (1)

[Claims] 1. A high-pressure sodium lamp device in which a high-pressure sodium lamp is connected to an AC power source via a ballast, and a lighting tube or a solid-state lighting element is connected to both ends of the high-pressure sodium lamp, wherein the high-pressure sodium lamp has both ends connected to the high-pressure sodium lamp. an arc tube with an inner diameter of 7 mm or less, the shortest distance between the electrodes being 25 mm or less, and filled with neon-krypton mixed gas as a starting rare gas;
20~ lit with AC power voltage of 100~120V
It is a 100W high pressure sodium lamp, and the pressure of the neon-krypton mixed gas is 30Torr.
A high-pressure sodium lamp device characterized in that the pressure is 250 Torr or less, and the partial pressure ratio of krypton gas to the neon-krypton mixed gas is in the range of 3% or more and 50% or less.