JPS58197648A - Metal vapor discharge lamp - Google Patents

Abstract

PURPOSE:To quickly turn off a lamp that goes into a starting fault and prevent unrequired high voltage from being generated in a circuit by providing an oxygen emitting body in close vicinity to a solid resistor made of a carbon coat resistor body. CONSTITUTION:When the life span of a lamp approaches to its end, the start of the lamp becomes worse by the deterioration of electrodes 6 and 7 and/or an increase of impure gas in a luminous tube 5. At the first opening of a bimetal switch 3, the lamp cannot come on and when the bimetal switch 3 is closed again, current flows again in a carbon coat resistor 17, a heater 16, and the bimetal switch 3 and the actuation of the bimetal switch 3 is thus repeated. As a result, since the temperature of the carbon coat resistor 17 rises gradually, an outer tube 10 may be cracked. Since an oxygen emitting body 18 in this invention is arranged in close vicinity to the resistor 17 in this case, said body 18 is liable to receive the heat of the resistor 17, subsequently suffering from generation of cracks, duly causing the oxygen sealed internally to be emitted in the outer tube 10. As a result, since the carbon coat of the resistor 17 is oxidized and the conductivity of the resistor 17 is lost, any voltage is prevented from being applied to the lamp subsequently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to metal vapor discharge lamps such as high pressure sodium lamps and metal halide lamps that can be operated using a mercury lamp ballast.

High-pressure sodium lamps and metal halide lamps are attracting attention as energy-saving light sources because they have higher efficiency than high-pressure mercury lamps.

However, compared to high-pressure mercury lamps, these lamps require a higher voltage to start the rung, so they must be lit with a ballast that includes a built-in high-voltage pulse generator, which necessitates the use of large and expensive ballasts. was forced to do so.

To solve these problems, high-pressure sodium lamps and metal halide lamps with built-in starters have recently been put into practical use. Figure 1 shows the lighting circuit for a strict high-pressure sodium lamp inside the starter;
) is a built-in high-pressure sodium lamp, (11) is a ballast for a high-pressure mercury lamp, and -a is a commercial power source. The starter (2) is composed of a bimetallic switch (3) and a heating resistor (4) consisting of a tungsten coil connected in series to the bimetallic switch (3), which is connected in parallel with nine arc tubes (5) and has an outer tube tendency. It is contained.

In addition, electrodes (61 (71) are provided at both ends of the 9 arc tube (6), and a starting aid (8) is provided to lower the starting voltage of the lamp. A starting aid bimetallic switch (9) for electrically disconnecting the starting aid (8) is also provided.

Starting the IJ lamp is performed in the following process. Upon application of the power supply voltage, current flows through the heating resistor (4) in the ballast housing 9 and the bimetal switch (3). It should be noted that the bimetal switch (3) is of a normally closed type, with its contacts normally closed and opened by heating.

In the above, when current flows through the heating resistor (4), the heat from the heating resistor (4) causes the bimetal switch (3
) is heated, the bimetallic switch (3) opens, and at this time, a high voltage is momentarily induced in the choke coil of the ballast Q0, and this high voltage causes a discharge between the electrodes (61 (71), and the lamp lights up. When the lamp is lit, the temperature of the first arc tube (5) rises, and the bimetallic switch (9) operates due to the heat, electrically cutting off the starting aid (8).

The heating resistor (4) has conventionally been made of a heat-resistant metal such as tungsten and wound around a ceramic substrate. However, as the lighting time of the lamp increases, the tungsten coil deforms gradually, sometimes sagging, or when the coils come into contact with each other, resulting in a short circuit.

Furthermore, the work of winding the tungsten coil around the ceramic substrate was quite time-consuming.

The present invention was made to eliminate such conventional drawbacks, and the heat generating resistor (4) is a fixed resistor made of a carbon film resistor, and an oxygen emitting body is further provided in the vicinity of this resistor. It is distinctive in that it has been installed.

This invention will be explained in detail below. FIG. 2 shows an embodiment of the invention. There are 9 arc tubes (5) inside the outer tube αQ.

A starter (2) is housed and an electrode (
6) (7) is provided, and a starting aid (8) made of molybdenum wire is wound around the outer periphery of the arc tube (5), and this end is connected to an insulating sleeve α3 ( 14). The bimetal switch (9) is in contact with the starting aid (8) when the lamp is started, but moves away from the starting aid (8) after the lamp is lit. The starter (2) is composed of a bimetallic switch (3), a heater for heating it, and a carbon film resistor aη. Luminous tube (5
) is made of aluminum J-tube, inner diameter 8mm, electrode +61mm.
(The length between 71 and 71 is approximately 90 m, and there is sodium inside.

In addition to mercury, xenon gas is sealed at 300'rorr. Carbon film resistor I has an outer diameter of approximately 1 mm and a total length of approximately 50 mm.
m, a carbon film is deposited on the surface of the insulator in a band shape,
Its resistance value is approximately 3000 at room temperature.

Heater a is a small-capacity heater with a 0.3 g tungsten coil in the form of a coil, a total length of about 20 flI, and a resistance value of about 50 at room temperature.

In addition, an oxygen emitter CIII is placed near the carbon film resistor αη.
is set by the holding body a field. This oxygen emitter a. is a glass tube in which approximately 1 atm of oxygen gas is sealed.

When the power supply voltage is applied, the cap (to) via the stabilizer Qυ
A current of 200 V is supplied to the carbon film resistor aη, the heater, and the bimetal switch (3).

The current at this time is mainly limited by the resistance value of the carbon film resistor a'0, which prevents the generation of abnormally high voltage pulses. The bimetal switch (3) is activated and becomes open, and the lamp lights up due to the high voltage generated in the ballast H. With this configuration, the heating resistance, which is a drawback of conventional starters, is eliminated. It has the advantage of eliminating sagging and short circuits of the tungsten coil in the body, and also makes it easier to manufacture the starter.

In this invention, 9 Normally, the lamp lights up when the metal switch (3) is opened for the first time, but at the end of the lamp's life, the electrodes (61+71) deteriorate and impure gas inside the arc tube (5). The increase causes the lamp to start more slowly,
-When the bimetal switch (3) is opened for the second time,
The lamp could not be lit and the metal switch (3) was turned on again.
) closes, the carbon film resistance becomes zero, current flows through the heater QG, and the bimetallic switch (3), and the bimetallic switch (3) operates repeatedly.

In this way, when the lamp starts, the power switch (3)
When the above operation is repeated, the temperature of the carbon film resistor rough η gradually rises from room temperature and reaches 700 to 1000°C. When the temperature of the resistor (Iη reaches such a high temperature.

There is a risk that the glass of the outer tube a. will be locally heated and cracks will occur, causing the outer tube α value to break. Since the oxygen releasing body 0 barrel in this invention is installed near the resistor αη, it is easily exposed to the heat of the resistor α force, causing cracks and releasing the oxygen sealed inside toward the outer tube. .

As a result, the carbon film on the resistor layer is oxidized, and the resistor α
Since the force is no longer conductive, no voltage is applied to the lamp anymore. In addition, in the above, oxygen emitter a
In order to make a glass tube easier to break, it is also possible to make scratches on the outer surface of the glass tube to take advantage of the fact that the glass tube is easy to break.

In the above, an example was shown in which the present invention was applied to a high-pressure sodium lamp, but it goes without saying that the present invention can also be effectively applied to other metal vapor discharge lamps such as metalnoride lamps.

As described above, the present invention has a starter including a thermoresponsive element together with an arc tube in the outer envelope, and a carbon film resistor for limiting the current flowing through the thermoresponsive element, in which oxygen is released near the resistor. The installation of the tungsten coil eliminates the sagging of the tungsten coil while the lamp is lit and the coil passage, and also prevents the tungsten coil from sagging during the lamp's life.
It has the special purpose of quickly rendering a lamp malfunctioning when it fails to start, and preventing unnecessary high voltage from being generated in the circuit.

[Brief explanation of the drawing]

FIG. 1 is a lighting circuit diagram of a conventional high-pressure sodium lamp embedded in a starter, and FIG. 2 is a sectional view showing an embodiment of the present invention. In the figure, (2) is a starter, (3) is a thermally responsive element, (
5) is the arc tube, (8) is the starting aid, OI is the outer tube,
Q71 is a carbon film resistor, and 08 is an oxygen emitter. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - Figure 1 Figure 2 Agony

Claims (2)

[Claims] (1) In a lamp in which a starter consisting of a thermally responsive element and a fixed resistor that limits the current flowing through the thermally responsive element is incorporated together with the arc tube in the lamp outer bulb,
The above fixed resistor consists of a carbon film resistor, and an oxygen release body is installed near the carbon film resistor to release oxygen when the carbon film resistor becomes abnormally high temperature.
A faint metal vapor discharge lamp. (2) The metal vapor discharge lamp according to claim 1, wherein the oxygen emitting body is constituted by a glass container filled with oxygen gas.