JPH08180834A - Red metal halide lamp - Google Patents

Abstract

PURPOSE: To provide a long-lived red metal halide lamp emitting a pure red light. CONSTITUTION: A light emitting tube 1 is approximately spherically formed by a light transmitting material such as quartz glass, and an outer tube 2 is formed around the light emitting tube 1 by a light transmitting material such as quartz glass so as to ensure a closed space. The closed space between the light emitting tube 1 and the outer tube 2 is evacuated, or a low pressure gas is sealed therein, so that the outside air is approximately and thermally insulated from the light emitting tube 1 to limit the cooling of the light emitting tube 1. A rare gas and a metal halide are sealed as discharge gas in the light emitting tube 1, and as the discharge gas, for example, xenon gas of 100Torr, 10mg of LiI (lithium iodide), and 5mg of CsI (cesium iodide) are sealed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a red metal halide lamp containing a metal halide.

[0002]

2. Description of the Related Art The use of light sources that emit red, green, and blue light in addition to white light has been widespread as special effect lighting and decorative lighting. As a system for obtaining these red, green, and blue lights, it is realized by combining an incandescent light bulb with a filter of a desired color, and such a system has a low luminous efficiency of the incandescent light bulb. The loss due to the filter is also added, making it inefficient.

[0003]

In the metal halide lamp, in order to improve the above problems, indium halide (In) for blue and thallium halide (Tl) for green are used to emit blue light. , Has realized a green-emitting color lamp.

On the other hand, lithium (Li) and sodium (Na) are known as metals that emit red light (Li
Emits light mainly at 670 nm and 610 nm, and Na emits light at 589 nm). When these metals are used in conventional metal halide lamps, the vapor pressure of lithium halide and sodium halide is low, and the number of atoms during discharge is predominantly mercury. For this reason, the light color is added with the red light emission of Li or Na, and the blue light emission of mercury is added, so that the light color is separated from the pure red color and is tinged with purple. Therefore, at present, the orange light from Na of the high pressure sodium lamp is used as red light.

Also, in the red discharge lamp disclosed in Japanese Patent Publication No. Sho 49-15015, the emission of light from mercury in the blue to green range is present and a pure red color is not obtained.
Furthermore, Li and Na have not been put to practical use because they have a strong erosion reaction on the quartz arc tube and have a significantly shorter lamp life than lamps of other light colors.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a red metal halide lamp which emits pure red and has a long life.

[0007]

In order to solve the above-mentioned problems, a red metal halide lamp according to the present invention is provided with at least one of Li, Na, K and Ca halides together with a rare gas in a light-transmitting arc tube. It is characterized in that one kind and a halide of Cs are encapsulated and that mercury is not contained.

[0008]

According to the present invention, at least one of halogenated (I, Br and Cl; F is excluded because it has too high a reactivity), Li, Na, K or Ca is filled in the arc tube filled with a rare gas. By enclosing one type, red light can be extracted, and by not enclosing mercury, the blue component light is not mixed, so that the purity of light does not deteriorate.

Further, it has been found that Li and Na have a small atomic radius and easily dissolve in the arc tube, but by enclosing a halide of Cs, this reaction can be suppressed.
Furthermore, halogenated Cs and halogenated Li, Na,
Make a compound compound with alkali metals such as K and Ca,
The vapor pressure rises and the red brightness also improves. Incidentally, since Cs has its emission region in the infrared, Li, Na, K, C
The color purity according to a) is not deteriorated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention. An arc tube 1 is made of a translucent material such as quartz glass and has a substantially spherical shape. The outer tube 2 is formed of a translucent material such as quartz glass so as to secure a closed space. A closed space between the arc tube 1 and the outer tube 2 is filled with a vacuum or low-pressure gas, and during operation of the lamp, the outside air and the arc tube 1 are substantially thermally insulated from each other, so that the arc tube 1 Has limited cooling.

A rare gas and a metal halide are enclosed as a discharge gas inside the arc tube 1. As the discharge gas, for example, 100 Torr xenon gas, 10 mg LiI (lithium iodide) and 5 mg CsI are used. (Cesium iodide) was used. The shape of the arc tube 1 is not limited to this, as a matter of course.

Further, the arc tube 1 of this embodiment is an arc tube for an electrodeless lighting system. The electrodeless lighting system means that an electromagnetic field is generated around the induction coil 3 by causing a high frequency current to flow through the induction coil 3 arranged around the arc tube 1, and this electromagnetic field maintains discharge inside the arc tube 1. It While the discharge is being maintained, the electrons inside the arc tube 1 receive kinetic energy due to the electromagnetic field and collide with the discharge gas atoms to give energy, and the discharge gas atoms are ionized,
It gets excited. The excited atom emits light when returning to the ground state, and is a system that uses this emission as light energy.

In this embodiment, an arc tube for an electrodeless lighting system has been shown as an example, but a metal halide lamp having a generally known electrode can also realize the present invention simply by changing the amount of enclosed gas. .

The lamp configured as described above is lit by using a high frequency power supply device (not shown), and spectral energy is emitted.
The distribution was measured. The result is shown in FIG. As a conventional example, the spectral energy distributions disclosed in Japanese Patent Publication No. 49-15015 are shown in FIGS. 5 and 6. As shown in these figures, the light emitted from the lamp of this example is significantly different in emission intensity in other color regions such as blue and green from the emission intensity of the red component of 670 nm and 610 nm emitted by Li. It is getting smaller. In addition, comparing with the spectral energy distribution of the conventional example, it is clear that the ratio of the emission energy of the red component to the intensity is large, and it can be seen that the red light source is good.

Further, in the lamp having the same structure as that of this embodiment and not encapsulating Cs, the quartz tube was eroded by Li from the beginning of lighting. After 100 hours, 85% or more of the lamps had a non-lighting phenomenon, and the remaining lamps had a large increase in the starting voltage (power). On the other hand, in the lamp of this example, the quartz tube (arc tube 1) was hardly eroded even after 3000 hours, and the non-lighting phenomenon did not occur.

In this embodiment, the example of the lamp using the halogenated Li is shown, but various kinds of red light can be obtained by using halogenated Na, K, Ca or the like. it can. As an example, FIGS. 3 and 4 show spectral energy distributions of Na and K, respectively. Furthermore, the redness can be adjusted by mixing these.

[0017]

As described above, according to the present invention, at least one of the halides of Li, Na, K, and Ca and the halide of Cs are placed in a light-transmitting arc tube containing a rare gas. To provide a metal halide lamp having good red light and a long life because pure red light can be extracted and high reactivity can be suppressed by encapsulating and containing no mercury. You can

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing an embodiment of the present invention.

FIG. 2 is an emission energy distribution chart of a lamp according to an example using Li of the present invention.

FIG. 3 is a light emission energy distribution diagram of a lamp according to an example using Na of the present invention.

FIG. 4 is a light emission energy distribution diagram of a lamp according to an example using K of the present invention.

FIG. 5 is a distribution chart of light emission energy of a conventional lamp.

FIG. 6 is a distribution chart of emission energy of a conventional lamp.

[Explanation of symbols]

 1 arc tube 2 outer tube 3 induction coil

Claims (2)

[Claims] 1. A light-transmitting arc tube is filled with at least one of halides of Li, Na, K, and Ca and a halide of Cs together with a rare gas, and does not contain mercury. A characteristic red metal halide lamp. 2. The red metal halide lamp according to claim 1, wherein the halogen is I, Br or Cl.