JPS63190245A - High-pressure metal vapor discharge lamp - Google Patents

Abstract

PURPOSE:To prevent the start delay of a lamp and eliminate the short circuit accident of a wiring and the danger of a fire by sealing one of helium, neon, argon, krypton, xenon, and nitrogen in an outer tube at the preset pressure. CONSTITUTION:At least one of helium, neon, argon, krypton, xenon, and nitrogen is sealed in an outer tube 4 at the pressure of 10<-3>-50 torr. Thereby, the start delay phenomenon can be prevented from occurring with a simple structure without sealing a radioactive material or using a complex lamp structure. Accordingly, a high-pressure metal vapor discharge lamp free from the short circuit accident of a wiring and the danger of a fire can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to starting aids for high-pressure metal vapor discharge lamps, in particular for compact high-pressure metal vapor discharge lamps.

Conventional technology High-pressure metal vapor discharge lamps have the features of high efficiency and large luminous flux, so they are widely used for outdoor lighting in large-scale facilities and streets. It is also becoming popular in the lighting field. Along with this, there is an increasing demand for compact lamps, and the development of double-end metal lamps using high silica glass such as quartz for the outer bulb is progressing.

These lamps are usually lit by a dedicated ballast equipped with a pulse generation circuit, and when the power is turned on, a high voltage pulse of several kV is generated from the pulse generation circuit in addition to the secondary voltage of the ballast between a pair of electrodes. is applied and the lamp starts. However, even when high voltage pulses are applied in this manner, it may take several seconds to several tens of seconds from turning on the power to starting the lamp in some cases. This is generally called a delayed start phenomenon.

The start delay phenomenon will be described in detail below.

A certain number of free electrons must be present within the arc tube for the lamp to start. That is, when a voltage is applied between the electrodes, these free electrons are accelerated by the electric field and repeatedly collide with the filled gas molecules, resulting in a so-called electron avalanche, which ultimately leads to a discharge between the electrodes. These free electrons are usually generated by the ionizing effect of radiation from naturally occurring radioactive substances or cosmic rays, but their number is small and even if a high voltage pulse is applied between the main electrodes, no discharge will occur. There are many cases where there is no. This is the startup delay phenomenon mentioned above.

When such a start-up delay phenomenon occurs, a high-voltage pulse of several kilovolts from the pulse generation circuit is applied to the wiring from the ballast to the lamp. Not only is it expensive, but as the equipment ages and the dielectric strength of the wiring decreases, dielectric breakdown may occur between wires or between the wires and the building, which may lead to short circuits and fires. There is. For this reason, it is necessary to suppress the normal startup delay time to 10 seconds or less.

Therefore, in order to avoid the start-up delay phenomenon, conventional techniques have been used to encapsulate a ceramic body containing radioactive materials in the arc tube, or to use a radioactive rare gas as the gas filled in the arc tube, thereby reducing the amount of radiation emitted from these. It has been proposed that free electrons are constantly generated within the arc tube by the ionization effect of .

Another conventional technique involves arranging a starting auxiliary circuit, such as a tungsten filament and a bimetal switch in series, inside the outer bulb, and irradiating visible light and ultraviolet light into the arc tube by first energizing this filament when starting the lamp. It has also been proposed to generate free electrons within the arc tube using the ionization effect of these.

Problems to be Solved by the Invention However, among these conventional techniques, the former involves handling radioactive materials during the lamp manufacturing process, so careful attention must be paid to their management. I can't say that. Regarding the latter, the lamp structure is not only complicated (in the case of compact double-ended lamps, the inner volume of the outer tube is limited, so it is extremely difficult to arrange the filament. There was a problem.

The present invention is a high-pressure metal vapor discharge device that prevents the occurrence of start-up delays with a simple structure without enclosing radioactive materials or using a complicated lamp structure, thereby eliminating the risk of wiring short circuits and fires. It provides a lamp.

Means for Solving the Problems The high-pressure metal vapor discharge lamp of the present invention comprises an arc tube having a pair of electrodes filled with a small amount of mercury and a rare gas and having no starting auxiliary electrode; A high-pressure metal vapor discharge lamp having an outer bulb containing an auxiliary starting circuit in the outer bulb, wherein the outer bulb contains a small amount of helium, neon, argon, krypton, xenon, and nitrogen. It has a sealed configuration with a pressure of 3 to 50 torr.

With this configuration, when the power is turned on and voltage is applied to the lamp, the gas sealed inside the outer bulb first generates a discharge between the lead wires inside the outer bulb, and this triggers a discharge inside the arc tube almost instantly. The lamp will now start.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a 150W double-ended metal halide lamp according to the present invention. In Figure 1, a pair of electrodes 1 are provided at both ends.
The arc tube 2 has crushing sealing parts 3a at both ends.
, 3b, and electrically connected to the electrodes 1a and lb, respectively.
, 5b, and is fixed to the outer tube 4 at the crush sealing portions 3a, 3b. The caps 6a, 6b are electrically connected to the electrodes 1a, Lb via sealing foils 7a, 7b and lead rods 5a, 5b, respectively. Inside the arc tube 2, predetermined amounts of mercury, thulium iodide, dysprosium iodide, holmium iodide, sodium iodide, thallium iodide, and argon are sealed at 120 torr. The inner diameter of the arc tube is 12
．． 5nu++, distance between electrodes is 17mm, outer tube inner diameter is 19
+am, the distance between the reeds 5a and 5b is 62 m.

Further, in the outer tube 4, at least one of helium, neon, argon, krypton, xenon, and nitrogen is sealed at a pressure of 10-3 to 50 torr.

When the secondary voltage of the ballast and high voltage pulses from the pulse generation circuit are applied to the lamp having the above configuration, a discharge of argon, which is the gas sealed in the outer bulb, occurs between the glue rods 5a and 5b in the outer bulb 4. As a result, discharge immediately starts between the electrodes 1a and lb of the arc tube 20, thereby preventing a delay in starting the lamp.

A specific example will be described in detail below.

In a lamp with the configuration shown in Figure 1, argon is supplied into the outer bulb.
Ten lamps each having different encapsulation values within the range of 0-4 to 50 Torr were manufactured, and the time required from turning on the power to starting the lamp was measured twice for each lamp. In this measurement, the ballast has a rated power supply voltage of 20
0V, the rated secondary voltage is 240V, the power supply voltage is 180V, which is 90% of the rated value, and the secondary of the ballast is subjected to a half cycle of high-voltage pulses with a pulse height of 4kV and a half-value width of 100 microseconds. It was superimposed once each time.

For comparison, similar measurements were also performed on a lamp whose outer bulb was evacuated. The results are shown in FIG. In FIG. 2, the horizontal axis (logarithmic scale) is the argon sealing pressure in the outer tube, and the vertical axis is the starting delay time, that is, the time required from turning on the power to starting the lamp. As is clear from the figure, in a lamp with a vacuum inside the outer bulb, the starting delay time may take three minutes or more depending on the case, and the starting delay time varies widely.

On the other hand, a lamp whose outer bulb is filled with 10-3 to 5 C1-L of argon has almost no start-up delay time (and its start-up performance is equivalent to that of a lamp filled with radioactive gas).

As described above, it is clear that the lamp startup delay time can be significantly shortened by filling the outer bulb with argon at a predetermined pressure. The reason for this is not necessarily clear, but by filling the outer bulb with gas, a glow discharge is first generated within the outer bulb between the lead rods of the arc tube, and the irradiation of ultraviolet rays generated by this glow discharge causes the gas filled in the outer bulb to It is assumed that the ionization causes the lamp to start.

Although the same effect can be obtained when the sealing pressure inside the outer tube exceeds 50 Torr, in this case, there is a problem that arc discharge occurs between the lead rods in the outer tube when the lamp is restarted, leading to melting of the lead rods. However, it is difficult to implement. On the other hand, if the sealing pressure is less than 1 O-3)-L, as shown in FIG. 2, discharge within the outer bulb is less likely to occur and the start-up delay time may exceed 10 seconds, which is also undesirable.

According to experiments, the sealing pressure within the outer tube was particularly preferably in the range of 10-2 to 20 Torr. The same effect can also be obtained by using helium, neon, krypton, xenon, and nitrogen alone or in combination with argon instead of argon as the gas sealed inside the outer tube. It was done.

In the above example, a 150W double-ended metal halide lamp was described, but similar results were obtained for a single-ended lamp. Further, the present invention is not limited to the wattage of the lamp and the substance sealed in the arc tube, but can also be applied to high-pressure mercury lamps and high-pressure sodium lamps.

As described in detail, the present invention includes an arc tube in which at least mercury and a rare gas are sealed in a container having a pair of electrodes and does not have an auxiliary starting electrode, and an outer tube housing the arc tube. , a high-pressure metal vapor discharge lamp having no starting aid circuit in the outer bulb, wherein the outer bulb contains at least one of helium, neon, argon, krypton, xenon, and nitrogen at a pressure of 10-3 to 50 Torr. By encapsulating the lamp, it is possible to prevent the start delay phenomenon with a simple structure without encapsulating radioactive materials or creating a complicated lamp structure, and therefore there is no risk of wiring short circuit or fire. A high pressure metal vapor discharge lamp can be provided.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a 150W double-ended metal halide lamp according to the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the argon filling pressure in the outer bulb and the start-up delay time. 1a, 1b... Electrode, 2... Arc tube,
4... Outer pipe, 5a, 5b... Lead rod. Name of agent Patent attorney Toshio Nakao and 1 other person

Claims (1)

[Claims] A high-pressure arc tube having at least mercury and a rare gas sealed in a container having a pair of electrodes and having no starting auxiliary electrode, and an outer tube accommodating the arc tube, and having no starting auxiliary circuit within the outer tube. In the metal vapor discharge lamp, at least one of helium, neon, argon, krypton, xenon, and nitrogen is contained in the outer bulb.
A high-pressure metal vapor discharge lamp characterized in that it is enclosed at a pressure of ~50 Torr.