JPS5864749A - Metal vapor electric-discharge lamp - Google Patents

Abstract

PURPOSE:To enhance the efficiency of a metal vapor electric-discharge lamp by preparing an emission tube from a polycrystalline or monocrystalline ceramic member, and sealing both ends of the emission tube with sealing ceramic members in each of which a metallic thin-film electric conductor connected to an electrode is sealed. CONSTITUTION:An emission tube 1 is prepared from a material such as alumina ceramic. Sealing members 4 used for airtightly sealing both ends of the tube 1 also are made of a material such as alumina ceramic. A metallic thin-film electric conductor 5, which is made of tungsten or the like, connected to an electrode 3, and supplies current to the electrode 3 from outside the emission tube 1, is airtightly sealed in each sealing member 4 by sintering work. The internal space of the tube 1 may be charged with a metal halide as well as with a metal such as Na or Hg. It also is charged with Xe gas or the like. As a result, the luminous efficiency of the lamp can be enhanced by reducing heat leaving from the ends of the tube 1 outside the tube 1.

Description

[Detailed description of the invention] The present invention relates to metal vapor discharge lamps.

■Lamp (Hlg), which has begun to attract attention as a high-efficiency light source
h Intensity Discharge Lam
p) ij In recent years, the range from high wattage to low wattage is being developed. One of the problems with low wattage 1'1II) lamps is the ratio of electrode loss to rated human power.

This means that they are larger than those with high wattage. This is due to the fact that the electrode loss is approximately constant regardless of the magnitude of the input. For this reason.

As the input amount contributing to so-called light emission, that is, the radiation loss, becomes smaller and the wattage becomes lower, the lamp efficiency becomes lower. One way to solve this problem is to reduce the size of the arc tube and increase the load on the tube wall to prevent a decline in lamp efficiency. The use of stable ceramics such as alumina is being considered. However, in this case, since a metal tube or metal wire is used at the end of the arc tube, the heat transfer coefficient is generally higher than that of a quartz arc tube, so the flow of heat to the end of the arc tube increases, resulting in poor lamp characteristics. There was a drawback that was difficult to overcome.

In other words, the lamp characteristics are determined by the temperature of the coldest point inside the arc tube. There were disadvantages in that when the temperature was low, sufficient input could not be obtained, and the lamp efficiency did not improve much.

Further explanation will be provided according to the drawings. Figure 1 shows a conventional lamp using ceramic as the arc tube. (l) is a ceramic arc tube, (2) is a heat-resistant metal tube such as N'fi, 'ra, etc. to 9 arc tubes (1). This is an electricity introduction member. Further, (3) is an electrode. H of the conventional structure as shown in Figure 1
In the case of a lamp, the heat conductivity of the heat-resistant metal tube (2) serving as the electricity introduction member is high, so there is a drawback that heat loss from the end of the waste light tube (1) cannot be completely suppressed.

The present invention was conceived in view of the above-mentioned problems, and it is an object of the present invention to provide a highly efficient lamp with little heat loss at the ends.

This will be explained below according to the drawings. That is, in Fig. 2, (
1) A Ti arc tube is used, and a ceramic material is used for this. (3) is an electrode provided at both ends of the arc tube (1), and (4) is a ceramic closure for vacuum-sealing both ends of the arc tube (1). 3)
A thin metal film electricity introducing member (5) made of tungsten or the like is connected to the electrode (3) and supplied with electricity from outside the arc tube (1), which is sintered and sealed in vacuum. This electrode (3),
The structures of the closure body (4) and the metal thin film electrical introduction body (5) are shown in an enlarged scale in FIG. In addition, in FIG. 3, (a) is a front sectional view, (b) is a side sectional view, and (C) is a Q-
It is a sectional view of C.

What is the method of hermetically sealing a metal thin film electrical introduction member (5) made of tungsten or the like in a ceramic material closure member (4)?

Two hand-held columnar ceramic press molded products as shown in Figure 4(b) were made, and after pre-firing, one of the molded products (B) was coated with tungsten, etc. as shown in Figure 4(a). A metal thin film electrical introduction body (5) is formed by applying a high melting point metal by a method such as printing, and then the other molded product (4) is covered and integrated, and then the final firing is performed. can be formed. Ceramic material closure obtained by this method (
4) can maintain vacuum tightness.

If a ceramic closure member (4) is used to seal the arc tube (4) as in the present invention, the end of the arc tube (1) will be more easily sealed than when a metal tube or metal wire is used. The luminous efficiency of the siramp increases as less heat escapes.

The arc tube (1) is made of alumina ceramic, magnesia ceramic, itria ceramic, or the like, but it is also possible to use single crystals of these oxides. However, alumina ceramic is especially excellent in terms of durability and cost efficiency. Also, as a material for the ceramic closure body (4).

Alumina, ittria, magnesia, etc. were good.

The metal to be deposited and fired inside the closing body (4) is preferably a metal with a high melting point, such as tungsten, molybdenum, tantalum,
Niobium is suitable, but compounds of these or mixtures of multiple metals may also be used.

In addition to metals such as Na and Hg, metal halides may be sealed inside the arc tube (1).

These selections are determined depending on what kind of spectral distribution is to be obtained. Also, inside the 6 arc tubes (1) are No.
, Kr, Xe, etc., but a mixture of these gases may also be filled. Of these, especially X, gas is 100
Enclosing more than Torr improves the lamp efficiency in particular, making it more advantageous as a lamp than a low wattage H. In that case, starting performance is not very good, so it is better to provide a starting aid on the outer wall of one arc tube.

Next, an example will be explained.

An alumina ceramic closure body (supporting four hawk electrodes (3)) with a tungsten thin film electricity introducing body (5) baked and sealed inside was sealed at both ends of an alumina ceramic arc tube (1) with an inner diameter of 6.6 tmi. Arrive, x8 gas and Na
- Hg amalgam is sealed in the arc tube, 100
We made a prototype of Watsuto's high-pressure sodium lamp. Note that a glass frit containing lanthanum oxide as a main component was used to seal the closing body (4) and the arc tube (1).

The efficiency of the lamp produced in this way was approximately 657W, compared to the 60Lm/w of a conventional 100W lamp, an improvement of approximately 8% in efficiency. Note that the color rendering properties of such lamps are the same as those of conventional lamps.
= 85, and no abnormalities were observed in the travel characteristics or other aspects during the 9000 hours of lighting.

Also, although a low wattage model was used in the explanation of the present invention, a 150W model was used.
Of course, the above-mentioned high-wattage products are also effective.

As explained above, the present invention uses a ceramic material as the arc tube material in a metal vapor discharge lamp, and a metal thin film electricity introduction body connected to an electrode is baked and sealed inside the closure body that closes and seals both ends of the arc tube. Since it uses a ceramic material that has been stabilized, it has the effect of improving lamp efficiency.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional ceramic arc tube, Fig. 2 is a block diagram showing a ceramic arc tube according to the present invention, and Fig. 3 is an explanatory diagram showing the structure of its electrodes and closing body. Front sectional view, (Here is a side sectional view. (→ is a C-a sectional view of It is a figure. In the figure, (1) is an arc tube, (3) is an electrode, (4) is a closure body. (5) is a metal thin film electric introduction body, and the same code|symbol shows the same or equivalent part. Agent Shin Kuzuno - Figure 2 Figure 1 Figure 3

Claims (2)

[Claims] (1) The arc tube is made of polycrystalline or single-crystal ceramic material, and both ends of the arc tube are made of ceramic material with a thin metal film electrical conductor sealed inside, which is connected to the electrodes arranged inside the arc tube. A metal vapor discharge lamp characterized in that it is closed and sealed with a closing body. (2) A metal vapor discharge lamp according to claim 1, characterized in that a metal halide is sealed inside the arc tube.