JPS60243999A - Method of firing high pressure sodium lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for lighting a high-pressure sodium lamp.

Conventional Structures and Problems With the arrival of a full-scale energy saving era, the development and commercialization of compact high-intensity discharge lamps to replace low-wattage incandescent light bulbs is actively underway. In particular, the applicant
A new small-sized high-pressure sodium lamp was proposed in JP-A No. 9045 and Japanese Patent Application Laid-Open No. 1986-50-63.

The high-pressure sodium lamp prototyped based on this proposal has a low lamp power of around 50W at rated lighting, and although the Shika lamp is equipped with a small alumina arc tube, it has high lamp efficiency. It has a light color similar to that of a light bulb and excellent color rendering. Therefore, it is expected that such small high-pressure sodium lamps will be introduced as a new energy-saving light source for indoor lighting, mainly in commercial facilities, and will take full advantage of their features.

However, when such a small high-pressure sodium lamp is lit with a commercial 50 or 60 Hz AC power source,
During the run, the lamp voltage may vary and the color of the emitted light may change accordingly. For example, when a 50W small group high color rendering high pressure sodium lamp like the one above is lit using a 60H7 commercial power supply using a magnetic induction ballast, the emitted light color will fluctuate, and the emitted light color recorded during the lamp life will vary. The minimum color temperature was 2470 and the maximum was 2660K. Alternatively, when 20 lamps of this type were prototyped and lit with the same type of ballast and the same power source (601-17, input 100), variations in light color among the lamps were clearly observed. When we measured the color temperature of the emitted light from these 20 lamps, the average value was 2500K, but the minimum was 241oK.
, the highest was at 2590.

These fluctuations in lamp light color during movement due to fluctuations in lamp voltage and variations in light color between lamps are due to the instability of the discharge arc of the arc tube, that is, the instability of the arc spot. In particular, in order to improve color rendition, IJ Umranop produced a lamp whose vapor pressure of thorium atoms during lamp operation was much higher than that of a general high-pressure sodium lamp, and which was powered by a commercial power source. 6
This problem cannot be avoided as long as the lamp is lit with alternating current in the Q-60 frequency range.

Purpose of the Invention The present invention has been developed in view of these problems, and it is an object of the present invention to suppress variations in lamp light color during movement and variations in light color between lamps to a level that does not cause any practical problems. The present invention provides a method for lighting a high-pressure sodium lamp that enables the following.

Structure of the Invention The present invention has an arc tube with an average inner diameter of φ(-). 〉130
The present invention is characterized by a high-pressure sodium lamp lighting method for lighting a DC lamp under the following conditions and with a discharge current ripple rate of 55% or less.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an arc tube used to carry out the method for lighting a high-pressure sodium lamp of the present invention. In the figure, 1 is an alumina arc tube with an inner diameter of 5mm, and end rings 2 made of alumina are attached to both ends of the tube.
, 3, a niobium tube 4.5 is sealed. Electrodes 6 and 7 are held at the tips of the niobium tubes 4 and 5, and the shortest distance between these electrodes is 10 degrees. Arc tube 1
Inside, a sodium amalgam 8 with a sodium molar ratio of about 80% and a neon/argon mixed gas as a starting rare gas are sealed. Reference numerals 9 and 10 denote thermal protection films made of tantalum, which are attached to the outer periphery of both ends of the arc tube 1 to prevent heat and light radiated from the interior of the arc tube 1, particularly from the electrodes 6 and 7, to the rear of the electrodes during lamp operation. It is confined in the coldest point of the arc tube that is formed and serves to raise the temperature of this coldest point.

FIG. 2 shows the electric circuit used in the lamp lighting experiment. Reference numeral 11 is a 50W high color rendering high pressure sodium lamp in which the arc tube 1 is built into the outer bulb 12, and when the lamp is lit at the rated voltage of 45V, the emitted color is 25.
Indicates 00K. 13 is a 100V, 6014 AC power supply, and this sinusoidal AC voltage is full-wave rectified by a rectifier 14 and applied to the high-pressure sodium lamp 11 via a resistance type ballast 15. 16 is a capacitor provided between the rectifier 14 and the resistive ballast 15, the capacitance of which can be changed so that the ripple rate of the discharge current of the high-pressure sodium lamp 11 during lighting can be set to an arbitrary value. That's it.

A lighting experiment of a high-pressure sodium lamp was conducted using the lighting circuit configured as described above. In the experiment, 20 50 W high color rendering high pressure sodium lamps 11 prototyped with the same specifications were prepared and lit, and the color temperature of the emitted light was measured by measuring the emission spectrum. This measurement was carried out by changing the ripple rate of the discharge current in the range of 5 to 70% by changing the capacitance of the capacitor 16.

FIG. 3 is a plot of the difference between the maximum and minimum color temperatures of the 20 lamps, that is, the maximum color difference ΔTM, measured at a constant ripple rate of discharge current. According to the figure, it can be seen that 47M increases gradually as the ripple rate of the discharge current increases, and increases rapidly when the ripple rate exceeds 56CH. As described above, the color temperature variation increases as the ripple rate of the DC discharge current flowing through the high-pressure sodium lamp 11 increases, because the probability that the arc spot of the discharge arc will fluctuate increases as the ripple rate increases. As a result, the temperature at the coldest point inside the arc tube 1 becomes increasingly fluctuated, and eventually the high-pressure sodium lamp 11
This increases the variation in emitted light color between lamps, or the variation in emitted light color between lamps.

As described above, as the ripple rate of the DC discharge current flowing through the high-pressure sodium lamp 11 during lighting increases, the maximum color difference ΔTM between the lamps increases, but as long as the ripple rate does not exceed 55%. Generally, the minimum color difference that causes discomfort, that is, does not exceed 100 degrees.

Incidentally, the tendency shown in FIG. 3 is similar to that of a 50W lamp equipped with an arc tube with an inner diameter of 6mm and an interelectrode distance of 10mm, and whose average potential gradient E at rated lighting is 45V/z, as in this example. Not limited to high color rendering high pressure thorium lamps, the average inner diameter is φ (
It has been confirmed that there is almost no change in the so-called high-pressure sodium lamp with improved color rendering, which is lit under the condition of E・φ〉130, where E is the average potential gradient at rated lighting. There is.

As described in detail, the present invention provides a high-pressure sodium lamp equipped with an arc tube with an average inner diameter of φ, and when the average potential gradient at rated lighting is E (V/17n), E.
Under the conditions of φ>13o and the ripple rate of the discharge current is 55
By lighting with a direct current of less than 100 volts, the fluctuation of the arc spot of the discharge arc is suppressed, and the variation in light color between lamps and the fluctuation in light color during the life of the lamp can be suppressed to a level that does not cause any practical problems. ) It is possible to provide a method for lighting an IJum lamp.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an arc tube used to implement the high-pressure sodium lamp lighting method of the present invention, FIG. 2 is a diagram showing an example of a lighting circuit for implementing the high-pressure sodium lamp lighting method of the present invention, and FIG. FIG. 3 is a relationship diagram between the ripple rate of the discharge current and the maximum color difference ΔTM.

Claims (1)

[Claims] For a high-pressure sodium lamp equipped with an arc tube with an average inner diameter of φ (TMl), the average potential gradient at rated lighting is E (
1. A method for lighting a high-pressure sodium lamp, characterized in that the lamp is lit under the condition that E-φ>13o, and the ripple rate of the discharge current is 55% or less.