JPH0151022B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a starting circuit for a metal vapor discharge lamp in which xenon gas of 100 torr or more is sealed as a starting rare gas.

Generally, high-pressure sodium lamps and metal halide lamps have better efficiency than high-pressure mercury lamps, and are advantageous as power-saving light sources. For this reason, high-pressure sodium lamps and metal halide lamps have recently been frequently used in place of high-pressure mercury lamps.
In this case, it is desirable to be able to light a high-pressure sodium lamp or metal halide lamp by using the existing ballast for a high-pressure mercury lamp.

However, since high-pressure sodium lamps and metal halide lamps have a higher starting voltage than high-pressure mercury lamps, it is difficult to start them simply with a high-pressure mercury lamp ballast, and special starting means are required. Therefore, metal vapor discharge lamps have been developed in which a starting circuit consisting of a bimetal switch and a heater connected in series with the bimetal switch to heat the bimetal switch is housed in the outer bulb and connected in parallel with the arc tube. . When you turn on the power supply voltage through the high-pressure mercury lamp ballast,
Since the bimetal switch is closed, the heater is energized, and the heat generated by the heater heats the bimetal switch, and the kick voltage when the bimetal switch is opened is superimposed on the secondary voltage of the ballast to generate a high voltage pulse. This high voltage pulse was applied between opposing electrodes in the arc tube to cause discharge. By the way, the conditions for starting a high-pressure discharge lamp are to form an ionized discharge path that can conduct electricity in the discharge space filled with a starting rare gas, and to connect the electrodes with sufficient high-voltage pulse energy. It is necessary to heat the cathode spot to a certain temperature to form a stable cathode spot. However, since the conventional starting circuit described above opens the bimetal switch by heating the heater, it takes a long time of several tens of seconds to repeat the opening and closing of the bimetal switch, and it takes a long time to repeat the opening and closing of the bimetal switch. In the meantime, the electrode and discharge path have cooled down and must be started in essentially a single pulse. For this reason,
The pulse wave height value requires an extremely high value, 3500
It is necessary to generate a high voltage pulse of ~5000V. However, when replacing high-pressure sodium lamps or metal halide lamps with existing lighting facilities equipped with ballasts for high-pressure mercury lamps, generating the above-mentioned high pulse voltage may cause problems such as insulation breakdown and burnout in older facilities. It was limited by voltage characteristics.

Particularly recently, xenon gas is used as a starting rare gas in high-pressure sodium lamps, and the pressure of this xenon gas is increased to 100 torr.
By doing the above, a lamp has been developed in which the restriking voltage of the lamp is kept low and the luminous efficiency is improved. This high-xenon high-pressure sodium lamp has extremely poor startability due to the high pressure of xenon gas, and requires an extremely high pulse voltage. However, as mentioned above, generating high voltage pulses is not preferable from the viewpoint of voltage resistance of the lighting facility.

This invention was made based on these circumstances, and its purpose is to repeatedly generate a low pulse voltage multiple times within a short period of time using a combination of an improved lighting tube and a current limiting resistor. , an object of the present invention is to provide a metal vapor discharge lamp which enables a lamp filled with xenon gas of 100 torr or more to achieve reliable lighting with short starting and restart times, and which does not cause dielectric breakdown in lighting facilities, etc. It is.

Hereinafter, specific examples of the present invention will be explained with reference to the drawings.

FIG. 1 shows the circuit configuration of a high-pressure sodium lamp, where 1 is an outer tube, and 2 is an arc tube made of a single crystal or polycrystalline material such as a translucent alumina tube or a sapphire tube. Inside the arc tube 2, electrodes 3, 3 are arranged facing each other. In addition, mercury as a buffer gas metal is contained in the arc tube 2.
Sodium as a luminescent metal and xenon gas as a starting rare gas are sealed at a gas pressure of over 100 torr. Further, a starting circuit formed by connecting a lighting tube 4 and a current limiting resistor 5 in series is housed within the outer bulb 1, and this starting circuit is connected in series to the arc tube 2. Furthermore, an auxiliary proximity conductor 6 for starting is provided in the outer bulb 1 in contact with or in close proximity to the outer surface of the arc tube 2, and this proximity conductor 6 is connected to the same polarity as one electrode 3 via a bimetal piece 7. connected so that Such a lamp is
It is connected to a power source 9 via a ballast for high-pressure mercury lamps, that is, a single yoke type ballast 8 .

As shown in FIG. 2, for example, the lighting tube 4 has a pair of bimetallic pieces 11, 11 provided facing each other in an airtight container 10, and contacts 12, 12 at the tips of these bimetallic pieces 11, 11. This airtight container 10 contains 5 to
It is filled with rare gas, mainly argon gas, at 9 torr.

Although the current limiting resistor 5 is not shown in detail, it is made of, for example, a carbon-coated resistor, and has a resistor on its surface to prevent reaction with impurity gas released from the arc tube 2, etc., and to reduce gas release from the resistor itself. A thin film of silicon carbide (SiC) is deposited on top. The resistance value of this current limiting resistor 5 is regulated within the range of 150 to 600Ω.

The combination of the argon gas pressure value of the lighting tube 4 and the current limiting resistance value is based on experimental results, and the experiment will be explained below.

Electrodes were provided at both ends of a translucent alumina tube with an inner diameter of 8 mm and a length of 114 mm, and a luminous tube 2 was constructed in which predetermined amounts of mercury, sodium, and xenon gas were sealed. About various gas pressures of xenon gas,
We investigated the pulse voltage required for starting using a conventional starting circuit consisting of a bimetallic switch and a heater. The purpose of using a conventional bimetal switch and heater is to check the pulse height value required to turn on the light by applying a single pulse. The results are shown in FIG.

It can be seen from Figure 3 that high-pressure sodium lamps filled with xenon gas of 100 torr or more for the purpose of lowering the restriking voltage and improving luminous efficiency,
If you try to turn it on with a single pulse, you will need a high voltage pulse of at least 3500V. However, as described above, such high voltage pulses are undesirable because they may damage the lighting facility.

Next, using a starting circuit based on the combination of the lighting tube 4 and the current limiting resistor 5 configured as shown in FIG. We also investigated how the number of pulses is changed. The results are shown in FIG.

What can be seen from Figure 4 is that the general trend is that
It can be seen that as the current limiting resistance value increases, the pulse peak value decreases, but conversely, the number of pulse generation increases.

Therefore, the starting performance of the lamp was investigated by variously changing the gas pressure of the argon gas sealed in the lighting tube 4. This results in 9 torr of argon gas
The characteristics of the filled lighting tube are shown by the solid line in Figure 4, and the characteristics of the lighting tube filled with 5 torr of argon gas are shown in Figure 4.
Indicated by the wavy line in the figure. Of course more than 10 torr and
We also experimented with lighting tubes of 4 torr or less, but the combinations in which the lamp can be started are those in which the argon gas in the lighting tube is in the range shown by the broken line and the solid line, that is, the range of 5 torr to 9 torr, and the current limiting resistance value is from 150
Limited to 600Ω range.

For those using a lighting tube filled with argon gas of 10 torr or more, no matter how much the current limiting resistance value is changed,
It is impossible to start an arc tube that is filled with xenon gas of 100 torr or more, and for a lighting tube that is filled with argon gas of less than 5 torr, the bimetal pieces 11, 11 shown in FIG. 2 are connected to the stem 13.
It has been confirmed that a pulse discharge occurs in the vicinity of the stem 13, causing a crack in the stem 13, resulting in a short service life, making it unusable.In addition, the glow discharge time becomes long and the number of pulses generated is relatively too small. It was hot.

Also, if the current limiting resistance value is less than 150Ω, the pulse voltage peak value will be high, but the number of pulses generated will be small, so it will not be possible to start.If it exceeds 600Ω, the number of pulses generated will be high, but the pulse peak value will be small. It cannot be started.

Therefore, by using a starting circuit in which a lighting tube 4 filled with 5 to 9 torr of argon gas and a current limiting resistor 5 whose resistance value is regulated to a range of 150 to 600 Ω are connected in series, a pulse voltage of 3500 V or less can be used. However, because many pulses are generated in a short period of time,
It becomes possible to start even high-pressure sodium lamps filled with xenon gas of 100 torr or more. This makes it possible to keep the pulse voltage low, and it is possible to start the lamp even with an average pulse voltage of about 1500V, so there is no need to apply high voltage to existing facilities, preventing damage to the facilities. It will be possible.

In the above embodiment, a high-pressure sodium lamp was explained, but metal halide lamps filled with xenon gas of 100 torr or more have recently been developed, and the present invention can also be applied to such lamps. It is not limited to examples.

In addition to filling the lighting tube with 5 to 9 torr of argon gas, an organic gas such as methane gas may also be mixed in. In this way, the discharge starting voltage of the lighting tube can be increased. effective.

According to the invention described in detail above, the starting circuit uses argon gas as a main component and the total pressure is 5 to 9 torr.
It is constructed by connecting in series a lighting tube filled with rare gas and a current limiting resistor with a resistance value of 150 to 600 Ω, so the pulse height value is relatively low, but the number of pulses generated is large. Since the energy administered to the arc tube increases, even arc tubes filled with xenon gas of 100 torr or more can be reliably started and restarted. Since the pulse peak value of this product can be kept lower than that of conventional products, it can be used safely even in existing high-pressure mercury lamp facilities without causing dielectric breakdown or burnout.

[Brief explanation of drawings]

The drawings show specific examples of the present invention. Figure 1 is a circuit configuration diagram of a high-pressure sodium lamp, Figure 2 is a configuration diagram showing an example of its lighting tube, and Figure 3 is a circuit diagram of an arc tube filled with xenon gas. FIG. 4 is a characteristic diagram showing the relationship between the current limiting resistance value, the pulse peak value, and the number of pulse generation times with respect to the argon gas pressure enclosed in the lighting tube. 1... Outer tube, 2... Arc tube, 3, 3... Electrode,
4... Lighting tube, 5... Current limiting resistor, 8... Ballast.

Claims (1)

[Scope of Claims] 1. A buffer gas metal, a luminescent metal, and xenon gas of 100 torr or more are sealed in an arc tube equipped with electrodes at both ends, and in order to start the arc tube, a total pressure mainly composed of argon gas is applied. A metal product characterized in that a starting circuit is connected in parallel with the above-mentioned luminous tube, and a starting circuit is formed by connecting a lighting tube sealed with a rare gas of 5 to 9 torr and a current limiting resistor of 150 to 600 Ω in series. Steam discharge lamp. 2. The arc tube is a high-pressure sodium lamp comprising a bulb made of a translucent single crystal or polycrystalline material, with electrodes at both ends, and filled with mercury, sodium, and xenon gas of 100 torr or more. A metal vapor discharge lamp according to claim 1.