JPH01100861A - High pressure metallic vapor electric discharge lamp - Google Patents

Abstract

PURPOSE:To prevent electrical discharge between outer lead wires even if high voltage is applied at the time of momentary starting by constituting the outer lead wires of the sealing section of a luminous tube in such a way as to be pulled out from the side face of said sealing section. CONSTITUTION:Metallic foils 4 and 4a at the sealing section 9 of a luminous tube 2 are arranged in a reversed V shape configuration. A pair of outer lead wires 6 and 6a are arranged toward vertical side against a lamp axis. In addition, it is desired that the relation between an interelectrode distance d1 and the outer diameter d2 of the luminous tube 2 shall be d1/d2<0.75. Owing to this constitution, even if high voltage is applied at the time of momentary starting, electrical discharge between the lead wires 6 and 6a can be prevented, thereby improving momentary restarting characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a high-pressure metal vapor discharge lamp, particularly to an improvement in a single-end waste light tube such as a small metal halide lamp of this type.

(Prior Art) In recent years, this type of high-pressure metal vapor discharge lamps such as metal halide lamps have become smaller in size and are being used in stores and the like. In particular, this type of lamp of 100 W or less has a compact shape as a single-end arc tube like a halogen lamp. Such an example is described in, for example, Japanese Unexamined Patent Publication No. 59-54167, and a vertical sectional view of the configuration example is shown in FIG. A pair of electrodes 3゜3a
An arc tube 2 equipped with a light emitting diode 2 is held and arranged within a small metal halide lamp outer tube 1 by support wires 5, 5a. Here, 4, 4a is a metal foil such as Mo (molybdenum), 6, 6a
are a pair of external lead wires for the arc tube electrode 3゜3a;
It consists of etc. 7.7a; 8 and 8a are the metal foil of the outer tube 1 and the external lead wire, respectively. Further, 9 indicates a sealed arc tube product, and 10 indicates an outer tube sealed part. Inside the arc tube 2,
It is filled with a luminescent metal such as mercury and a starting gas, and the inside of the outer tube 1 is kept in a substantially vacuum state to maintain high efficiency.

[Problem that the invention seeks to solve]

Due to its compactness, the above-mentioned small high-pressure metal vapor discharge lamp shown in Figure 7 is often used in the same way as an incandescent lamp or halogen lamp, and therefore requires no switch during use. An instant restart characteristic that allows the lamp to turn on again immediately after being turned off is also a necessary characteristic that this type of small metal vapor discharge lamp must have.

Here, - numerically, a high-pressure metal vapor discharge lamp usually:
In the case of instantaneous restart as described above, since the gas pressure in the mercury or other inclusion body is still high, a high voltage pulse is required to start the discharge. For example, a mercury lamp requires a high electric field of 2-3 V/cm.

High-pressure metal vapor discharge lamp with a normal double-capped arc tube (
(not shown), the electrodes 3 and 3a as well as their sealing parts are present at both ends of the arc tube 2, so even if such a high pulse is applied, discharge will start between the electrodes and restart will be achieved. . This is because the distance between the ends is sufficiently long compared to the inter-electrode distance d1.

However, in the case of a small single-cap type high-pressure metal vapor discharge lamp as shown in FIG. 7, due to its structure, the interval between the external lead wires 6.
There will be no big difference from IIld1. Therefore, when a high pulse is applied during restart, discharge does not start between the electrodes 3 and 38, and the arc tube 2 is led out! There was a possibility that a problem such as discharge occurring between 6.6a and 6a would occur. Therefore, it is difficult to restart the compact high-pressure metal vapor discharge lamp having the structure shown in FIG. 7 instantly, which has been one of the reasons for preventing its widespread use.

The present invention was made in view of the problems of the prior art as described above, and an object of the present invention is to provide a compact high-pressure metal vapor discharge lamp of this type having good instantaneous restart characteristics.

[Means for solving problems]

For this reason, in this invention, a small high-pressure arc tube having a pair of electrodes inside and a single-capped arc tube with a picture electrode sealing part on one side is disposed inside a substantially vacuum outer tube. The metal vapor discharge lamp is designed to achieve the above object by configuring the external lead wire of the sealed portion of the arc tube to be led out in that direction from the side surface of the sealed portion.

[Effect]

As described above, since the external lead wires of the sealed part of the arc tube are taken out from the side of the sealed part, the interval between the external lead wires can be increased, and therefore, high voltage is applied during instant start. Also, it is possible to prevent discharge between the external leads, and the instantaneous restart characteristics are improved.

〔Example〕

The present invention will be explained below based on examples.

FIG. 1 is a longitudinal cross-sectional view illustrating the structure of an embodiment of a small single-cap type high-pressure metal vapor discharge lamp according to the present invention. Identical (equivalent) components in FIG. 2 of the prior art example are represented by the same reference numerals, and redundant explanation will be omitted.

(Structure) The pair of electrodes 3 and 3a are made of tungsten or tribuum tungsten, and are coated with an electron emitting substance that is compatible with the additives of the inclusion body containing mercury. For example, Sc
For types containing scandium (scandium), scandium oxides such as 50203 and Dy (dysprosium)
Those containing dysprosium oxides such as Dy2O3 are used. The arc tube 2 is filled with a predetermined amount of the additive, Ar (argon), and Penning gas (eg, Ne-Ar).

When the lamp is started at a cold temperature, these gases are discharged to provide power to the lamp and serve to evaporate additives, and while the lamp is on, the gases make little contribution to light emission. In addition, when the temperature is high, i.e., when the power is turned on immediately after turning off the lamp by -degrees (during instantaneous restart), the electrode 3.3
Since the evaporated additive is present between electrode 3
．． A high voltage is applied between 3a to restart the engine. This is because the electrons emitted from the electrodes 3, 3a due to the electric field are energized by the additive atoms and therefore require larger energy.

As described above with reference to FIG. 7, if there is not much difference between the spacing between the electrodes 3 and 3a and the spacing between the outer lead wires 6.6a of the arc tube, the outer tube! Since there are no additives inside and it is essentially a vacuum (rare gas may be enclosed), a discharge (arc discharge) occurs between the external lead wires 6 and 6a by applying a high voltage. In such a case, the bases of the external lead wires 6, 6a may melt and the lamp may not light up. As mentioned above, such a failure is hardly a problem in a double-cap type arc tube because the external lead wires are far apart from each other, but in a single-cap type arc tube as shown in Figure 7, it is not a problem. , had become a big problem.

As a result of various studies, the inventors of the present application found that each electrode 3.3a
It has been found that the above failure can be avoided by taking out the external lead wires 6, 6a from the side surface of the arc tube sealing part 9 as shown in FIG. By adopting such a structure, the substantial distance between the inner and outer lead wires 6 and 6a (outer tube 1
This is because the shortest distance (the shortest distance of the part exposed to the internal space) can be made longer.

(Operation/Test) In accordance with the principles of this invention, a small metal halide lamp having a structure as shown in FIG. 1 was actually prototyped and tested. Inside the arc tube 2, a Dy-Tl-Na halide is sealed together with an additive, and the gas inside is Ar.
Torr was enclosed. A few mg of mercury was also added. D7zOs is applied as the electrode of the arc tube 2 in Fig. 1,
A pair of sintered electrodes 3.3a is provided, and the picture electrodes 3,3a
The distance d was set to 6 mm. External lead wire of arc tube 2 6.
6a is 12 mm, and the inner diameter of outer tube 1 is 1
8 mm, and the inside is essentially evacuated. The metal foil 4.4a of the sealing part 9 of the arc tube 2 is made of Mo (molybdenum) and arranged in a square shape.

The pair of external lead-out lines 6 and 6a are arranged in a vertical side direction with respect to the lamp axis L (indicated by a dashed line).

A voltage of 2,000 V was applied to this prototype lamp at cold temperature to start discharging, and after the characteristics were sufficiently stable, the power was cut off. has started.

On the other hand, two arc tubes with the same capacity. When we made a prototype for a comparison test with the structure of the sealing part 9 as shown in the conventional example shown in FIG. A failure such as sputtering of the external lead wires 6, 6a occurred. Furthermore, the inventors have determined that the distance d1 between the electrodes and the outer diameter d2 of the arc tube 2 are
It has been found that this invention will not be fully effective if the relationship between That is, as shown in FIG. 2, in order to find the relationship between the interelectrode path II dr and the outer diameter d2 of the arc tube 2, the configuration shown in FIG. 1 is obtained by varying dr/d2 one by one. When we made a number of prototype lamps and conducted the instantaneous restart test described above, we found that d I/ d 2
It has been revealed that the present invention is effective when <%=0.75.

When d1/d2>%, that is, when the interelectrode path 111d-1 approaches the outer diameter d2 of the arc tube, it goes without saying that the external lead-out wires 6 and 6a tend to start discharging. In addition, since the applied voltage is originally a pulse voltage (or high electric field) sufficient to start a discharge between the electrodes in the gap dl, if d, ~ d2 (asymptotic), then at instantaneous restart If the discharge starting voltage between the electrodes increases, it is natural that discharge will occur in the external lead wires 6 and 6a. Therefore, the critical value of d1/d2 becomes a problem. The significance of the critical value of d+/d2 being approximately % is that the experimental results using various additives and gases are almost in agreement, so that the discharge starting voltage at restart is within the arc tube 2. This shows that it almost depends on the vapor pressure of mercury.

Another advantage of the present invention is that, as shown in a second embodiment in FIG. This can be greatly increased. This means that in a conventional configuration such as the arc tube 2 shown in FIG. 7, only portions A and Aa of the inner diameter of the arc tube 2 are led out, as shown in FIG. ! Although it is not possible to increase the distance between the outer lead wires 6 and 6a, according to the present invention, the outer lead wires 6 and 6a are
It is possible to increase the distance between the two to ensure the effect.

(Other Embodiments) As a second embodiment of the present invention, as shown in FIG.
The distance between the electrodes d1 is 7 mm, and the outer diameter d2 of the arc tube is 11 mm.
A small 5c-Na metal halide lamp was prototyped. Inside, mercury and Ne-Ar gas as a rare gas were sealed at 30 Torr. The electrode is tungsten 5c20.
is applied as an electron emitting material and sintered. The outer tube is made of quartz and has an inner diameter of 16m+o. The interior of the outer tube l is vacuum. The arc tube 2 has a shape in which the length Ds of the crushed portion of the sealing portion 9 is larger than the outer diameter d2 of the arc tube 2, as shown in FIG. 3, and the value of Ds is 13.5 mm. Therefore, d, /d2=0.636<0.75 and d2<D
It is s.

For comparison purposes, we also tested a conventional lamp with a shape as shown in Figure 7, with dimensions d, = 7, and d2 = 11.
．． Ds = 11 and the distance 6 (
A sample lamp with the same specifications as above (m), such as the additive electrode, etc., was also manufactured and a comparative test was conducted.

When the same instantaneous restart test as described above was carried out on 20 lamps of the present invention and 20 conventional lamps, the lamps of the present invention restarted instantaneously without any problems, whereas the conventional lamps of FIG. In such a lamp, a vacuum discharge occurs between the 15 external lead wires 6 and 6a, and the external lead wires 6 and 6a may melt or the sealing portion 9 may crack and leak. Then the light went out.

Note that FIG. 4 shows a third embodiment of the present invention, and FIG. 5 shows a step diagram of its manufacturing process. 11 is an exhaust pipe, 12.12a is a pair of pressbeds for sealing, and 13.13a is a pair of slits. Further, FIG. 6 shows a fourth embodiment in which the arc tube is further miniaturized.

〔Effect of the invention〕

As explained above, according to the present invention, instantaneous restart can be performed reliably, and a small high-pressure metal vapor discharge lamp can be used in the same way as an incandescent lamp. can promote the spread of

[Brief explanation of the drawing]

FIG. 1 shows a compact high-pressure metal vapor discharge lamp according to the present invention.
・A vertical cross-sectional view showing the structure of the embodiment, FIG. 2 is a characteristic diagram of the distance between electrodes and the outer diameter ratio of the arc tube according to the present invention, and FIG. 3.5.6 is a sealing part of the arc tube according to the present invention. The second part of the configuration
．． 3.4 is a sectional view of the embodiment, FIG. 4 is a perspective view explaining the manufacturing process of FIG. 3, FIG. 7 is a longitudinal sectional view showing the structure of an example of a conventional high-pressure metal vapor discharge lamp, and FIG. , is a sectional view of an example of a sealing portion of a conventional arc tube. 1-----Outer tube 2. The corresponding components are shown.

Claims (3)

[Claims] (1) It has an arc tube that holds a pair of electrodes in a substantially vacuum outer envelope and seals an inclusion body containing mercury, and the arc tube has:
In a single-cap type high-pressure metal vapor discharge lamp in which a lead-out portion of the pair of electrodes to the outside is disposed on one side of the arc tube, an external lead-out wire from the sealing portion of the arc tube is connected to the sealing portion. A high-pressure metal vapor discharge lamp characterized in that the lamp is configured to be led out from a side surface in the direction of the side surface. (2) The high voltage according to claim 1, characterized in that when the distance between the pair of electrodes is d_1 and the outer diameter of the arc tube is d_2, d_1/d_2<0.75. Metal vapor discharge lamp. (3) The high-pressure metal vapor discharge lamp according to claim 2, wherein d_2<D_s, where the width of the crushed surface of the sealing portion of the arc tube is D_s.