JPS5935350A - High pressure metal vapor discharge lamp - Google Patents

Abstract

PURPOSE:To improve electron emanation characteristic of a discharge lamp while making an emitter without ThO2 by a method wherein an emitter consisting of BaO, CaO, SrO and one or more of Nb2O5, Ta2O5, HfO2, ZrO2, Y2O3, and Al2O3 is borne by an electrode. CONSTITUTION:An electron emanation material 3 consisting of BaO: 50%, CaO: 15%, SrO: 10% and more than one of Nb2O5, Ta2O5, HfO2, ZrO2, Y2O3 and Al2O3: 5-25% in mol% is made to be borne by an electrode core rod 4 of a high pressure metal vapor discharge lamp. Further, an inner coil 2 is arranged close to the core rod 4 while the outer coil 1 is arranged further outside thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an electrode for a high-pressure metal vapor discharge lamp in which a metal such as mercury and a rare gas are sealed, and particularly to improvement in workability and cost reduction of an emitter in this type of electrode.

Conventional emitters contain thorium oxide, which is designated as a nuclear fuel material, and their work is carried out according to established work standards, which has the disadvantage of considerably reducing work efficiency. Therefore, such emitters have the disadvantage of being extremely expensive.

Therefore, an object of the present invention is to provide a high-pressure metal vapor discharge lamp having an electrode supporting a new emitter that does not contain thoria, which is designated as a nuclear fuel material, and whose electron emission characteristics are equivalent to or better than conventional products. There is a particular thing.

For this reason, niobium, tantalum, hafnium, yttrium, and aluminum are close in physical properties to doria.

A silang test was conducted using a combination of high melting point oxides of zirconium, and the initial lighting voltage and luminous flux maintenance factor were measured to evaluate the emitter. As a result, the mixing molar ratio of each of the above oxides was 50 mol%BaCO5゜15-eAl'10C
acos, lQ mol% 5 to SI'CO3
It was confirmed that the properties were superior to conventional products when the content was within the range of 25 mol%.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. As shown in Fig. 1, a very common 400 watt high pressure mercury lamp electrode or a 360 watt high pressure mercury lamp electrode has a double coil 1 in contact with the electrode core frame t and a single coil 2 on the outside.
For electron emitting material 3, 50 mol% barium carbonate, 15
Ternary carbonates of mol% calcium carbonate, 10 mol% strontium carbonate and 5-25 mol% niobium, tantalum, hafnium, zirconium, yttrium.

After blending with at least one substance selected from the group consisting of aluminum oxides, a suspension of amyl acetate and nitrocellulose is applied to the electrode, and after drying it is applied for about 1 so.
It was baked and fixed in a mildly reducing atmosphere furnace of OC. The lighting test conditions were as follows: A 400-watt high-pressure mercury lamp with a transparent outer bulb consisting of electrodes fixed with various electron-emitting substances 3 was prototyped, and 10
A flashing test was conducted in which one cycle was one cycle of turning on for one minute and turning off for 20 minutes, and the electron emitting material 3 was evaluated based on the luminous flux maintenance rate and the average value of the discharge starting voltage at room temperature. Examples of the composition and mixing molar ratio of the electron emitting material 3 according to the present invention and the test results are shown in Tables 1 and 2 and FIG. 2.

In Table 1, Table 2 and Figure 2, the conventional electron emitting material containing thorium is indicated by N1, and the material according to the present invention which does not contain niobium, tantalum, hafnium, zirconium, yttrium, aluminum or thorium is indicated by M. . Although not shown in the above examples, the molar ratio of the winter substance mixed is 25
Even if it exceeds mol % or is less than 5 mol %, no significant effect will be obtained. Therefore, the effective mixing molar ratio in the present invention is preferably in the range of 5 to 25 mol%. Note that FIG. 2 shows an example of a luminous flux movement curve of a high-pressure metal vapor discharge lamp using the electron emitting material according to the present invention.

Table 2 The high-pressure metal vapor discharge lamp according to the present invention has electrode emitters containing 50 mol% barium oxide, 15 mol% calcium oxide, 10 mol% strontium oxide, and 5 to 25 mol%.
It is characterized by being made of at least one kind of substance consisting of niobium, tantalum, hafnium, silconium, yttrium, and aluminum oxide, and has a higher luminous flux maintenance rate and discharge starting voltage than conventional materials containing thorium. Both are excellent, and a long-life high-pressure metal vapor discharge lamp can be obtained without using thorium oxide, which requires careful handling. It goes without saying that when the electron-emitting material of the present invention is used in a high-pressure sodium lamp as well as a high-pressure mercury lamp, the same excellent effects as in the case of a high-pressure mercury lamp can be obtained in the lamp characteristics.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional structural view of an electrode for a high-pressure metal vapor discharge lamp on which the electron emitting material according to the present invention is coated and fixed, and FIG. 2 shows an electrode on which the electron emitting material according to the present invention is coated and fixed. It is a luminous flux movement curve diagram of a high-pressure metal vapor discharge lamp. 1... Outer coil, 2... Inner coil, 3... Electron emitting material 2nd 1st mouth ■ z Diagram: 5 people round (

Claims (1)

[Claims] 1.50 mol% barium oxide, 15 mol% calcium oxide, 10 mol% strontium oxide, 5~
It is characterized by having an electrode supporting 25 mol% of an electron-emitting substance consisting of at least one selected from the group consisting of niobium oxide, tantalum oxide, hafnium oxide, zirconium oxide, yttrium oxide, and aluminum oxide. High pressure metal vapor discharge lamp.