JPS60227349A - Dc high pressure sodium vapor and metal halogenide 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 The present invention relates to a direct current operated high pressure sodium vapor or metal halide lamp comprising two main electrodes (anode, cathode) mounted in a translucent discharge vessel made of translucent or transparent material. each electrode having at least two gas or vapor phase components disposed near each end of the discharge vessel and suitable for being excited to emit light during operation.

By high-pressure metal halide lamp is meant a high-pressure discharge lamp containing certain noble gases and mercury as starting gases, in which at least metal halides are also present. Such lamps can, for example, contain sodium iodide, thallium iodide and indium iodide, or sodium iodide and scandium iodide, or dysprosium iodide and thallium iodide.

If a high-pressure discharge lamp has a normal symmetrical configuration, i.e. the design of the cathode and anode is the same, when supplied with direct current, a substantial part of the halides will be located on the cathode side of the discharge vessel. to the edges, resulting in color separation. That is, the color of the light emitted from one end of the discharge tube is different from the color of the light emitted from the other end. This phenomenon is particularly relevant when operating the lamp in a vertical configuration.

When lamps of symmetrical design containing sodium iodide J1, thallium iodide and indium iodide are operated on AC power, the sodium iodide tends to migrate to the bottom of the discharge tube and is emitted from the lower end of the discharge tube. The light from the upper end becomes more yellow (characteristic of sodium) than the light from the upper end. If the same lamp were operated with direct current, two different situations would be observed. If the cathode is at the bottom, the color separation phenomenon will be stronger, while if the cathode is at the top, the color separation will be less pronounced.

In the present invention, a high-pressure sodium vapor lamp refers to a discharge (di
charge vessel), and during operation,
A high-pressure lamp is meant with a sodium vapor pressure in the range from 20 to 1000 mbar, a mercury vapor pressure in the range from 0 to 5 bar, and a xenon vapor pressure in the range from 50 to 30,000 mbar. In some of these lamps, mercury is replaced by a metal with high molecular weight and high vapor pressure, such as cadmium, and xenon is replaced by other noble gases, such as argon or neon-argon mixtures. There is. From the point of view of the present invention, these types should also be considered high pressure sodium vapor lamps.

When high-pressure sodium vapor lamps and metal halide lamps are supplied with direct current, the normal color uniformity associated with alternating current supply is lost and electrophoresis (electophoresis) occurs.
Color separation occurs with dispersion of the individual components due to etiology (esis or calaphoresis). For example, in a high pressure sodium vapor lamp, the faster ionizing component, ie sodium, migrates to the cathode end, causing a similar migration of all other components. At the cathode side end,
There will be more sodium light discharge. This phenomenon is called color separation, and this undesirable phenomenon is one of the reasons why devices with DC-powered high-pressure sodium vapor or metal halide lamps have not gained a foothold in this field. An exception is in the case of high-pressure sodium vapor lamps, where, in addition to sodium, mercury, cadmium, thallium, and/or zinc, etc., also produce optical excitation, when color separation is used for the purpose of exciting luminescent components. In such cases, color separation will be provided by the possibility of increasing the color temperature, but at the same time the luminous efficiency will decrease.

To reduce the effects of color imbalance due to component separation,
For example, measures can be taken to frost the outer glass bulb or apply a fluorescent powder coating. Such color separation does not occur when high pressure sodium vapor or metal halide lamps are powered by an alternating current source because the polarity is frequently reversed.

It is an object of the present invention to provide a solution which makes it possible to eliminate or minimize the phenomenon of color separation that occurs in high-pressure sodium vapor or metal halide lamps supplied with direct current due to the presence of several luminescent components and the component dispersion action of the direct current. It is to be.

During operation, the present invention also maintains the temperature of the cathode-side cold spot of a high-pressure sodium vapor or metal halide lamp at a level that exceeds the temperature of the anode-side cold spot of the lamp. , the recognition that by keeping the ratio of the distance between the main electrodes to the inside diameter of the discharge tube below a certain value, it is possible to meet the requirement of eliminating or limiting undesired color separation to an acceptable level. It is based on "Cold spot temperature" means the temperature that occurs in the coldest part of the discharge tube during operation.

Thus, the object of the present invention is likewise based on the above recognition that, in the case of a DC power supply, the effects of color separation can be eliminated or minimized to very low, tolerable levels by high-pressure sodium vapors or metals. The purpose is to create a halide lamp.

Correspondingly, the present invention provides a discharge vessel (preferably the discharge vessel is enclosed in an outer sphere) made of a translucent or transparent material, each main electrode (anode, cathode) near each of the ends of the discharge vessel. ) and a filling containing at least two gas or vapor phase components suitable for being excited to emit light during operation, the invention relates to a DC-fed high-pressure sodium vapor or metal halide lamp comprising: Suitable configurations exist for maintaining the cathode cold spot temperature of the vessel at a level above the anode cold spot temperature during operation.

Furthermore, the present invention provides a tubular discharge vessel made of a translucent or transparent material, a main electrode (anode, cathode) disposed near each of the ends of the discharge vessel, and suitable for being excited to emit light during operation. and a discharge vessel filling containing at least two types of gas phase or vapor phase components, and the distance between the main electrodes and the inner diameter of the discharge vessel is less than 7, preferably less than 5, for use in a DC power supply. Relating to high pressure sodium vapor lamps. By increasing the ratio to 7, color separation is reduced, and by reducing the ratio to less than 5, color separation can be completely eliminated in most cases.

In a preferred embodiment of the lamp according to the invention, the desired relatively high cathode side cold spot temperature is at the end of the discharge vessel and at the end of the main electrode near the end of the discharge vessel (i.e. the origin of the arc).
This is achieved by making the distance between them shorter on the cathode side than on the anode side.

In another preferred embodiment of the lamp according to the invention, the relatively high cold spot temperature on the cathode side is achieved by making the part of the discharge vessel close to the cathode narrower than the part close to the anode.

Instead of mechanical means as described above, electrical current solutions may also be used. Thus, in another preferred embodiment, a heating element is provided on the outside of the discharge vessel on the cathode side.

Again, in another preferred embodiment of the lamp according to the invention, the side of the discharge vessel facing the cathode is provided with a heat-reflecting surface, thereby ensuring the required relative high temperature.

Advantageously, a heat-reflecting surface is applied on both the anode side and the cathode side, or on the part of the discharge vessel facing the cathode and the anode, so that the cathode side has a heat-reflecting surface with a higher heat-reflecting capacity than that used on the anode side. It is appropriate to use the surface. This objective can be achieved, for example, by choosing a thicker heat-reflecting layer on the cathode side or by using better thermal insulation on the cathode side.

Another way to improve thermal conditions is to use an object that constitutes a heat-reflecting surface and to make each longitudinal geometric dimension of the object larger on the cathode side of the discharge vessel than on the anode side.

By virtue of the arrangement according to the invention, no color separation or a very low level of color separation along the long axis of the discharge vessel occurs in high-pressure sodium vapor or metal halide lamps operated in this manner with a direct current power supply. It is ensured that a uniform color distribution is obtained in the lamp. Measures to prevent color separation can be made even more reliable by adopting a configuration in which two or more of the above-mentioned measures are combined in various ways and simultaneously adopted.

In the following, the invention will be explained in detail on the basis of embodiments described by way of example with reference to open planes.

The DC powered high pressure metal halide lamp shown in FIG. 1 is constructed to ensure best results when operated in a vertical position with the cathode located higher than the anode. In this lamp, a discharge vessel 1 is enclosed in an outer bulb 2 and a bracket 3
．． 4, and the bracket is the lamp cap 5.
It acts as a conductor to supply current to the main electrodes (cathode 6 and anode 7) through. The cathode 6 is located in the cathode part of the discharge vessel 1,
The anode 7 is arranged in the anode section. The high pressure metal halide lamp is operated in the disclosed position with the cathode 6 at a higher level than the anode 7. This is because this arrangement itself ensures a relatively high temperature around the cathode 6, so that the temperature of the cold spot on the cathode side will be higher than the temperature of the cold spot on the anode side. The required effect is further increased by mounting the cathode 6 closer to the end of the discharge vessel than the opposite anode 7. The purity of the gas inside the outer sphere 2 is ensured by the getter 8. The desired effect is further enhanced by having light reflective surface 10 have better reflective properties than surface 11. Such good light reflection ability can be obtained, for example, by applying a zirconium-oxide coating.

FIG. 2 shows a DC-operated high-pressure sodium vapor discharge lamp in which a discharge vessel 21 is mounted in an outer bulb 22, the cross-section of the discharge vessel 21 near the cathode 26 being narrower than the cross-section near the anode 27; This increases the cold spot temperature on the cathode side and eliminates the color separation phenomenon. The plankets 23, 24 act as mechanical supports and serve to conduct the current through the cap 25 to the cathode 26 and the anode 27 as main electrodes. Getter 28 degass or cleans the space within outer sphere 22.

In the embodiment shown in FIG. 3, a heating member 29 is provided at the cathode end 26 of the discharge vessel 21 of the high-pressure sodium vapor lamp.
keeps the cold spot near the cathode 26 at a higher temperature than the cold spot near the anode 27. The outer sphere 22 is fitted with a cap for supplying current through blankets 23 and 24. The getter 28 is known in the art. fulfill the purpose of

FIG. 4 shows a high-pressure sodium vapor lamp similar to FIG. 3, but instead of the heating element 29, the cathode of the discharge vessel 21 is equipped with a heat-reflecting surface 30 consisting of a niobium ring.

The rated input power of this high pressure sodium vapor lamp is 35 watts. The discharge vessel 21 is a ceramic tube with an inner diameter of 3.3 mm, the distance between the cathode 26 and the anode 27 (arc length) is 40 mm, and the width of the niobium ring is 5 mm.
It is. In this example, the ratio between the distance between the main electrodes and the inner diameter is about 12.1. In such cases, strong color separation will occur unless special measures as described above are taken. Only more than half of the discharge vessel 21 emits light as a sodium vapor lamp, and the light emitted by the remaining part of the discharge vessel is filled with the mercury spectrum.

The high pressure sodium vapor lamp shown in FIG.
and the anode 27 and the inner diameter 3 of the discharge vessel 21.
．． It has dimensions of 3 mm. Therefore, the ratio between the distance between the main electrodes and the inner diameter of the tube is approximately 3, and in this case no color separation is observed, so no color separation can be achieved other than by meeting the appropriate dimensions prescribed by the invention. There are no other measures necessary to prevent it. In other respects the construction of this lamp is similar to the sodium vapor lamp described in the previous example.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a high-pressure metal halide lamp according to one embodiment of the present invention, FIG. 2 is a cross-sectional view of a high-pressure sodium vapor lamp with a tubular discharge vessel according to one embodiment of the present invention, and FIG. 3 is a cross-sectional view of a high-pressure metal halide lamp according to one embodiment of the present invention. Cross-sectional view of a high-pressure lamp with a heating element according to the fourth embodiment.
5 is a cross-sectional view of a high-pressure sodium vapor lamp provided with a light-reflecting surface according to one embodiment of the present invention; FIG. 1-discharge vessel, 2-outer sphere, 3.4-blanket, 5-cap, 6-cathode,
7-Anode, 8-Getter, 10. (11)-light reflective surface, 21-
Discharge vessel, 22 Outer sphere, 23.24- Plunket, 25- Cap, 26- Cathode, 27- Anode, 28- Getter, 29- Heating member, 30- Heat reflective surface. Patent Applicant Tungusram Reshenutarsa Sag Patent Application Agent Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Tetsuji Koga Patent Attorney Akira Yamaguchi Patent Attorney Masaya Nishiyama Figure 14 Figure 40

Claims (1)

[Claims] 1. A high-pressure sodium vapor or metal halide lamp for direct current operation, comprising a discharge vessel made of a translucent or transparent material, and a main electrode near each end of the discharge vessel. an anode and a cathode, and at least two suitable for being excited to emit light.
and means for maintaining the temperature of the cold spot at the cathode end of the discharge vessel higher than the temperature of the cold spot at the anode end during operation. A lamp featuring 2. The distance between the end of the discharge vessel and the end of the main electrode adjacent thereto as the base point of the discharge is shorter at the cathode end than at the anode end. lamp. 3. A lamp according to claim 1 or 2, wherein the discharge vessel is narrower at its cathode end than at its anode end. 4. A lamp according to claim 1, characterized in that the cathode side end includes additional heating means for heating the discharge vessel from the outside. 5. The lamp according to claim 1, wherein the cathode side end of the discharge vessel has a heat-reflecting surface. 6. The discharge vessel further includes a heat reflective surface on both the cathode side end and the anode side end, such that the heat reflective surface provided on the cathode side end is higher than the heat reflective surface provided on the anode side end. The lamp according to claim 1, which also has a large heat reflecting ability. 7. Both the cathode-side end and the anode-side end of the discharge vessel are further provided with a heat-reflecting surface formed by a layer, and the layer constituting the heat-reflecting surface on the cathode-side end serves as a heat-reflecting surface on the anode-side end. 2. A lamp according to claim 1, wherein the lamp is thicker than the layer constituting the surface. 8. Both the cathode side end portion and the anode side end portion of the discharge vessel are further provided with a heat reflecting surface formed by a layer, such that the heat insulating ability of the layer constituting the heat reflecting surface on the cathode side end portion is greater than that of the cathode side end portion. 2. A lamp according to claim 1, in which the heat reflecting surface of the lamp is higher than that of the layer constituting the heat reflecting surface of the lamp. 9. Further comprising an object having a heat reflective surface on both the cathode side end and the anode side end of the discharge vessel, and the geometric dimension of the heat reflective surface on the cathode side end is equal to the cathode side heat reflective surface. 2. A lamp according to claim 1, wherein the lamp is larger in each major axis direction than the geometric dimensions of the heat reflective surface of the anode end. 10. The lamp according to claim 1, wherein the discharge vessel is enclosed in an outer bulb. 11. A high-pressure sodium vapor lamp for direct current operation,
A tubular discharge vessel made of a translucent or transparent material, including an anode and a cathode as main electrodes disposed near both ends thereof, and at least two gas phase or vapor phase components suitable for being excited to emit light during operation. a filling, characterized in that the ratio of the distance between the cathode and the anode to the inner diameter of the discharge vessel is less than 7. 12. The lamp of claim 11, wherein the ratio of the distance between the cathode and the anode to the inner diameter of the discharge vessel is less than 5.