JPH06349446A - Metal-vapor discharge lamp - Google Patents

Abstract

PURPOSE:To eliminate the melting of stem glass inside an outer bulb after the lighting for a long time, and to prolong the lifetime by cracking the outer bulb stem glass with the energy at the time of generating a discharge inside an outer bulb, and flowing the outside air into the outer bulb. CONSTITUTION:A lead wire 12 is connected to the end of a lead-in conductor 5b having a potential (opposite potential) different from the potential of a stem lead 4a, to which a barium getter 10 is connected, and a longer lead-in conductor 5a, and the tip of the lead wire 12 is formed into a sharp conical shape (needle- like) to concentrate the electric field, and extended to a central part of an outer bulb stem 3. The energy (heat) of discharge inside of the outer bulb 1 can be thereby concentrated to the central part of the stem 3 to crack the stem glass with the thermal impact. Since the outer air is flowed into the bulb 1 with the crack, even in the case where a light emitting tube 6 is leaked after the lighting for a long time and the starting rare gas or the like is leaked into the bulb 1 to generate a discharge inside of the outer bulb 1, melting of the stem glass inside of the outer bulb is eliminated to improve the safety and prolong the lifetime.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a metal vapor discharge lamp in which the inside of an outer bulb is held in a vacuum by a getter, and a stem melting due to an arc tube leak or an outer bulb discharge when an outer bulb leak occurs. Regarding prevention of.

[0002]

2. Description of the Related Art A metal vapor discharge lamp known as a metal halide lamp in which a metal halide is enclosed in a quartz arc tube or a high pressure sodium lamp in which sodium and mercury are enclosed in a translucent alumina tube is an inner surface of the arc tube by a metal additive. In some cases, the arc tube may be eroded, and the arc tube may be cracked due to thermal shock when the lamp is turned on or off, and a rare gas for starting or a metal additive may leak into the outer bulb to cause arc tube leakage. Then, if such a lamp is left in the lighting fixture with the power on, the metal additive attached to the inner surface of the outer bulb evaporates due to the discharge in the outer bulb caused by the voltage supplied from the ballast or the starting pulse. As the vapor pressure inside the outer bulb rises or the temperature of the support column etc. rises, the discharge inside the outer bulb tends to be sustained, and eventually arc discharge may occur. Also, when the outer sphere cracks due to strain remaining in the outer sphere sealing portion and a slow leak occurs, the same phenomenon as described above is observed.

Such a phenomenon is due to the fact that the entire lamp is compact even in a discharge lamp in which an arc tube is supported in the outer bulb through a support having a stem lead and two long and short lead conductors in the outer bulb stem. Especially, it is often found in discharge lamps where the stem leads are adjacent to each other and the lamp power is small. Further, it often occurs in the upper part of the stem leads of different potentials to which the getter material is connected among the stem leads. When an arc discharge occurs in this portion, the glass on the upper part of the stem is melted due to the high temperature caused by the arc discharge, and the melted glass becomes a conductor, so that a current is applied between the leads inside the stem. In such a state, even if the outer bulb reaches a complete leak due to melting, the stem glass continues to be melted and the mouthpiece is heated to a temperature higher than the normal operating temperature, which may cause damage to the tool holder. Further, when the lamp is turned on with the base facing upward, the melted glass may drop and cause a crack in the outer bulb.

Further, since the metal vapor discharge lamp has excellent life characteristics and luminous efficiency, a low power lamp having a lamp power of 150 watts or less is used as a light source for indoor lighting.
For these lamps, in order to reduce the size and weight of the ballast, an electronic ballast of high frequency lighting or rectangular wave lighting is often used. And, since such an electronic ballast has a high ability to maintain arc discharge, the above-mentioned phenomenon is more likely to occur.

[0005]

In a metal vapor discharge lamp with a vacuum inside the outer bulb, a ring-shaped barium getter is used to adsorb the impure gas inside the outer bulb and maintain the degree of vacuum. This barium getter is supported by a nickel support wire connected to one of the introduction conductors at a position located on the stem on the outer cap side. The barium getter is used by flushing by high frequency heating after sealing the outer sphere and exhausting the gas in the outer sphere. At this time, the getter agent may remain in the ring to some extent.

When the arc tube leaks during lighting and the starting rare gas or metal additive leaks into the outer bulb, the outer bulb becomes an intermediate state between atmospheric pressure and vacuum, and the inner bulb discharges. Occur. At this time, an arc discharge is generated between the barium getter and the other stem lead or the supporting column having a different potential (opposing potential). Observing the current waveform in this case,
The current flows from the other stem lead, which has a potential opposite to the barium getter, in the direction of the barium getter, and the getter material remaining in the getter ring lowers the emission and makes it easier to maintain the discharge. It is considered that arc discharge occurs mainly in the getter. Also, in the case of a slow leak of the outer sphere, arc discharge is considered to occur for the same reason. In order to prevent the occurrence of the discharge in the outer sphere, air may flow into the outer sphere so that the outer sphere is in substantially the same state as the outside air.

The present invention has been made in view of the above, and an arc in the outer bulb due to an arc tube leak or an outer bulb leak after a metal vapor discharge lamp in which the outer bulb is kept in a vacuum is lit for a long time. An object of the present invention is to provide a long-life metal vapor discharge lamp that prevents the occurrence of discharge and does not melt the stem glass in the outer bulb.

[0008]

According to the present invention, an arc tube is supported through two long and short lead-in conductors connected to a stem lead set in an outer bulb stem in an outer bulb having a base fixed to one end. With the metal vapor discharge lamp in which a getter material is connected to the base side of the one introduction conductor and the inside of the outer bulb is held in a vacuum, the outer bulb stem glass is cracked by the energy when the outer bulb discharge occurs. It is characterized in that the outside air flows into the outer bulb. Further, a lead wire is connected to one of the introduction conductors to which the getter material is connected and the other introduction conductor of a different potential, the lead wire extending to the central portion of the stem, and the electric field is concentrated at the tip portion thereof. It has a sharp structure. Further, the arc tube is made of a translucent alumina tube having electrodes sealed at both ends, and sodium amalgam and a rare gas are sealed inside.

[0009]

With the above structure, the stem glass can be positively cracked and the outside air can flow into the outer bulb before the outer bulb glass is cracked or the stem glass is melted by the discharge in the outer bulb.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In the figure, it is an outer bulb of a 1 high-pressure sodium lamp, and a base 2 is fixed to one end. The outer bulb stem 3 is sealed at the end of the outer bulb on the base side. A pair of stem leads 4a and 4b are erected on the outer bulb stem 3, and the ends of two long and short lead conductors 5a and 5b are connected to the tip end of the stem leads 4a and 4b to form an arc tube column. The other ends of the stem leads 4a and 4b are connected to the terminal portions of the base 2, respectively. Reference numeral 6 denotes an arc tube in which electrode supporting tubes 7a and 7b are sealed at both ends of a translucent alumina tube and sodium, mercury and xenon gas are sealed inside.
And are supported in the outer sphere by being connected via arc tube leads 8a and 8b. Further, a ring-shaped barium getter 10 is connected to the base side of one of the longer ones of the introducing conductors 5 via a support wire 9 made of nickel, and is arranged in the vicinity of the outer ball stem 3. In addition, 11 shows the getter agent flushed to the inner surface of the outer sphere.

FIG. 2 is a schematic explanatory view showing a main part of the outer ball stem, and a pair of stem leads 4 erected on the outer ball stem 3.
As described above, the introduction conductors 5a, 5 having two long and short lengths are provided on a and 4b.
b and the ring-shaped barium getter 10 are connected, and the lead wire 12 is provided at the end of the introduction conductor 5b having a different potential (opposing potential) from the stem lead 4a to which the getter 10 is connected and the longer introduction conductor 5a. Connected. The tip of the lead wire is sharply formed in a conical shape (needle shape) for concentrating an electric field, and extends to the central portion of the outer sphere stem. By using such a lead wire, the energy (heat) of the discharge in the outer bulb can be concentrated in the central portion of the outer bulb stem, and the stem glass can be cracked by the thermal shock.

Next, an experimental example of the discharge lamp according to the present invention will be described. Ten high-pressure sodium lamps having a lamp power of 100 watts were manufactured according to the above example. The setting values of the electric characteristics of these lamps are 100 (W), 80 (V),
1.53 (A), the total length of the arc tube is 135 (mm),
The outer diameter is 35 (mm). Then, by increasing the input of these lamps and repeating blinking, forcibly leaking the arc tube, connecting a ballast, applying a voltage and continuing glow discharge in the outer bulb for 10 hours, several Within 10 minutes, the stem glass of all the lamps cracked and the discharge in the outer bulb stopped. Therefore, neither cracks in the outer bulb glass nor melting of the stem occurred.

Further, the set value of the electric characteristic is 150 (W), 1
00 (V) and 1.90 (A), and the total length of the arc tube is 150
(Mm), ten 150 watt high pressure sodium lamps with an outer diameter of 40 (mm) were made. When an experiment similar to the above was conducted on these lamps, no discharge occurred in the outer bulb and no melting of the stem occurred in any of the lamps.

Although the high pressure sodium lamp has been described in the above embodiment, a metal halide lamp may be used.

[0015]

As described above, according to the present invention, in the discharge lamp in which the inside of the outer bulb is kept in vacuum, the discharge energy in the outer bulb is utilized for cracking the stem glass to let the outside air flow into the outer bulb. This prevents the arc tube from leaking after long-time lighting, starting rare gas and metal additives leaking into the outer bulb, preventing cracking of the outer bulb glass and melting of the stem glass when an outer bulb discharge occurs. can do. And, the accidental accident that the glass part of the stem is melted and the base becomes higher than the normal operating temperature and the bracket of the device is damaged does not occur, and a highly safe and long-life discharge lamp can be obtained. You can

[Brief description of drawings]

FIG. 1 is a side view of a metal vapor discharge lamp according to the present invention.

FIG. 2 is likewise a schematic illustration of an outer bulb stem.

[Explanation of symbols]

 1 outer bulb 2 base 3 outer bulb stem 4a, 4b stem lead 5a, 5b introduction conductor 6 arc tube 7a, 7b electrode support tube 8a, 8b arc tube lead 9 nickel support wire 10 barium getter 12 lead wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiko Tsuge 1-1 Iriyama-cho, Gyoda-shi, Saitama Iwasaki Electric Co., Ltd. Saitama Factory (72) Yujiro Takano 1-1 Iriyama-cho, Gyoda-shi, Saitama Iwasaki Electric Co., Ltd. Saitama Factory

Claims (3)

[Claims] 1. An arc tube which has a base fixed to one end, supports an arc tube through two long and short lead conductors connected to stem leads planted in the outer bulb stem, and at the same time, the one lead conductor. In a metal vapor discharge lamp in which a getter material is connected to the base side of and the inside of the outer bulb is kept vacuum, when the outer bulb discharge occurs, the energy causes the outer bulb stem glass to crack and the outside air to flow into the outer bulb. A metal vapor discharge lamp that is designed to do so. 2. A lead wire is connected to one lead-in conductor to which the getter material is connected and the other lead-in conductor having a different potential, the lead wire extending to the central portion of the stem and the electric field concentrated at the tip portion thereof. The metal vapor discharge lamp according to claim 1, wherein the metal vapor discharge lamp has a sharp structure. 3. The metal vapor discharge lamp according to claim 1, wherein the arc tube is made of a translucent alumina tube having electrodes sealed at both ends, and sodium amalgam and a rare gas are sealed inside.