JPS5814524Y2 - kouatsu sodium lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-pressure sodium lamp having an arc tube inside an outer bulb.

This type of high-pressure IJum lamp has a color temperature of 2100.
In addition, the color rendering property is low at about 27 in terms of average color rendering index, making it unsuitable for use as a lamp for general lighting.

Therefore, in order to improve the color temperature and color rendering properties, it has been considered to significantly increase the sodium vapor pressure within the arc tube during lighting.

According to this, the above-mentioned purpose is achieved to some extent, but the lamp voltage increases as the sodium vapor rises, making the lamp more likely to go out.

Therefore, in order to prevent the ballast from turning off, it is usually necessary to provide a step-up transformer in the ballast to significantly boost the power supply voltage 200 cm, which results in an increase in the price of the ballast.

Furthermore, when the vapor pressure of sodium increases, the reaction between sodium and alumina of the arc tube material increases, causing the sodium in the arc tube to disappear, changing the color of the emitted light, and shortening the life of the lamp.

In view of the above-mentioned problems, an object of the present invention is to provide a high-pressure sodium lamp that increases the color temperature without increasing the lamp voltage and emits white or nearly white light.

The present invention achieves a color temperature of 2,400 to 3,000 by absorbing the emission spectrum of sodium in neodymium oxide (Nd203) mixed into the heat-resistant glass of the outer tube without changing the sodium vapor pressure inside the arc tube. 1 in 100 Average color rendering index 70-90. Moreover, a high-pressure sodium lamp with excellent characteristics such as a lifespan of 12,000 hours is realized.

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an arc tube made of a translucent alumina tube, and end caps 2 and 3 made of the same alumina material as the arc tube 1 are sealed at the ends of the tube with cement.

Furthermore, the niobium tubes 4 and 5 for conduction are connected to the end cap 2.
, 3 are sealed with the same cement.

Tungsten coil electrodes 6, 7 filled with oxide emitters are held at the tips of the niobium tubes 4, 5.

The arc tube 1 is filled with sodium as a luminescent substance, mercury or cadmium as a buffer gas, and xenon gas or a neon+0.5% argon mixed gas as a rare gas for starting.

As shown in FIG. 2, the light-transmitting arc tube is constructed by incorporating neodymium oxide having the spectral transmittance shown in FIG. A lamp is produced.

When the above-mentioned lamp is lit, an emission spectrum as shown in curve A in FIG. The spectrum changes as shown by curve B in the figure.

FIG. 5 shows the relationship between lamp voltage and lamp color temperature.

In FIG. 5, curve I shows the characteristics of the lamp in which magnesium oxide is mixed in the glass of the outer bulb according to the present invention, and curve ■ shows the characteristics of the transparent lamp.Especially in the low lamp voltage range, the color temperature is The range of rise is large, and as the lamp voltage becomes higher, the range of rise becomes smaller.

The reason for this is thought to be that as the lamp voltage increases, the self-absorption width of the sodium D line widens, so that the substantial absorption by diram oxide becomes smaller.

Next, an example of implementing the present invention will be described with reference to FIG.

The inner diameter of the arc tube 1 is IO, 8 mm, the distance between both electrodes is 53 mm, and the arc tube 1 is filled with 20 Torr of xenon gas, 15 mm of sodium, and 30 m of mercury. When a lamp manufactured by incorporating neodymium oxide into the glass into the outer bulb 8 was lit at a lamp voltage of 120V using a current 400W high-pressure sodium lamp ballast, the average color temperature of the lamp was approximately 2850. It exhibited very excellent properties with a color rendering index of 85.

Efforts to have neodymium oxide mixed in the glass of the outer bulb absorb the emission spectrum emitted from arc tubes or filaments have already been used in high-pressure mercury lamps and incandescent light bulbs.

However, in incandescent light bulbs, the mercury line 577 is used for a special color rendering effect that makes reds and greens look beautiful, and in high-pressure mercury lamps,
-579 is partially cut to prevent the yellowish appearance of human skin tones and improve color rendering.

However, neither of them aims to increase the color temperature, and is completely different from using neodymium oxide to increase the color temperature of the lamp as in the present invention.

As is clear from the above explanation, according to the present invention, it is possible to increase the color temperature without increasing the lamp voltage, thereby making it possible to use an inexpensive ballast, and to make the luminescent color white or white. A similar high-pressure sodium lamp can be realized, and its applications are not limited to outdoor lighting or part of indoor lighting as in the past, but can be used widely, and its practical effects are very large.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the arc tube of the high-pressure sodium lamp according to the present invention, Fig. 2 is a front view showing an embodiment of the same lamp, Fig. 3 is a view showing the transmittance of neodymium oxide, and Fig. 4 5 is a diagram showing the emission spectrum emitted from the arc tube and the lamp spectrum according to the present invention, and FIG. 5 is a diagram showing the relationship between the lamp voltage and the color temperature of the lamp. 1... Arc tube, 8... Outer tube.

Claims (1)

[Scope of utility model registration request] 1. A high-pressure sodium lamp having a light-transmitting luminous tube sealed with sodium inside the outer bulb.