JPS61138497A - Discharge lamp lighting apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a lighting device for a high-pressure discharge lamp such as a high-pressure sodium lamp or a metal halide lamp with a built-in starter.

[Prior art]

Generally, commercial power supply (AC 50/60Hz, 100V
High-pressure sodium lamps and metal halide lamps, which are lit using a choke coil type ballast for high-pressure mercury lamps (or 200 V), have a built-in starter because their starting voltage is higher than that of high-pressure mercury lamps, for example, as shown in Figure 1. It is composed of That is, in FIG. 1, reference numeral 1 denotes an arc tube that is equipped with a pair of main electrodes 2.3 and an auxiliary electrode 4 disposed adjacent to one of the main electrodes 2, and contains Na iodide and iodine along with l1g and rare gas. Chemical Sc etc. are enclosed. A series circuit of a starter 5, a current limiting resistor 6 and a bimetal switch 7 is connected in parallel between the main electrodes 2 and 3 of the arc tube 1, and a connection point between the current limiting resistor 6 and the bimetal switch 7 and an auxiliary electrode 4 are connected in parallel. are connected to each other via a resistor, and these are arranged in an outer bulb (not shown) to constitute a high-pressure discharge lamp. Note that 9 is a choke coil type ballast for a high-pressure mercury lamp.

A vacuum switch or a glow switch is usually used as the starter 5, and it generates a high voltage pulse (IKV or more) once every few cycles or seconds to first create an auxiliary discharge between the auxiliary electrode 4 and the adjacent main electrode 2. Then, the main electrode 2.
The discharge lamp is lit by generating a main discharge for 3 hours.

In this way, in conventional lighting devices for high-pressure discharge lamps such as metal halide lamps, the switching operation of the glow switch used as a starter, that is, the generation of high-voltage pulses, occurs approximately once every few cycles. Although the peak value of is 1ooov or more, the probability of causing dielectric breakdown between the main electrodes is low, and the effect of sustaining the discharge is also low, so starting is often uncertain. Therefore, in order to ensure reliable starting, it is necessary to increase the energy of this high voltage pulse, for example,
A method of applying a pulse of 600V peak and a width of several m5ec or a method of applying a high pulse voltage of 2 to ν or more (for example, a pulse height of 2 to 3 KV and a pulse width of 50 to 100μ5ec) have been used.

However, even if the peak value and pulse width of the pulse voltage are increased in this way, when a glow switch is used as a starter, the pulse height and width tend to vary, resulting in uncertain starting. there were.

Various proposals have been made to improve these drawbacks. For example, in Japanese Patent Application Laid-Open No. 5S"101876, a series circuit consisting of a normally closed bimetal switch, an impedance resistor larger than the ballast impedance, and a glow switch is connected in parallel with the arc tube between both electrodes, and the glow switch A discharge lamp lighting device is shown in which the power supply voltage is applied between the main electrodes even in the closed state, and the auxiliary discharge is sustained, and the main discharge between the main electrodes can be started at a low voltage.However, the impedance resistance is 100%. ~100
Since 0Ω Kanthal wire, Nichrome wire, etc. are used, when used with a 200Ω commercial power supply, the switching current due to the glow switch is 0.2 to 2. As with the conventional example shown above, the number of pulses generated is small, and the height and width of the pulses tend to vary, making starting difficult and uncertain.

Furthermore, in Japanese Patent Application Laid-open No. 5.5-130064, a starting circuit in which a glow switch, an impedance element, and a normally closed thermally responsive switch are connected in series is connected in parallel with the arc tube and installed inside the outer tube bulb. The gas pressure of the glow switch is set to 15 torr or less. However, if the fill gas pressure of the glow switch is set to 15 torr or less, although a high pulse voltage can be obtained, the number of pulse generation cannot be increased, and therefore, when such a lighting tube is used, starting is still difficult. The disadvantage is that it is difficult.

Furthermore, in Japanese Patent Application Laid-open No. 53-1977, a reed relay circuit consisting of a parallel circuit of a reed switch and an excitation coil of the reed switch is connected between a pair of main electrodes of an arc tube,
It is shown that 1 to 30 pulses with a peak value of 1000 V are applied in a half cycle to enable easy and reliable lighting with a low starting voltage. However, the excitation coil for this reed switch requires a winding of 10,000 turns and must be installed close to the reed switch, and when these lighting devices are built into the outer tube, the temperature inside the outer tube is 300 degrees Celsius.
In addition, in this example, the switching resistance of the reed relay circuit is 500 Ω, and the switching resistance of the reed relay circuit is 500 Ω, which is 200 Ω. In this case, a current of 0.4A flows through the reed switch, and several times in a half cycle
The disadvantage is that the contacts are subject to significant wear and tear as they flash several dozen times.

Furthermore, Japanese Patent Laid-Open No. 53-16475 describes a lighting circuit in which a bimetal switch circuit consisting of a bimetal switch and a resistor connected in series with the bimetal switch circuit is connected in parallel to a discharge tube. resistance to Ro
, when the power supply voltage is V, V/Ro≦1 is shown, and when the bimetal switch is closed, a high frequency voltage is generated to start the discharge lamp. However, with this method, the operation of the bimetal changes once every few seconds to tens of seconds.
The high frequency voltage is generated only for 100 m5ec = l sec when the bimetal closes. Therefore, the generation of high frequency voltage is short and there is a drawback that starting is uncertain. Furthermore, since high voltage pulses of 1000 V or more are generated by switching in a vacuum, there are also problems such as the need to create a vacuum around the bimetal.

[Purpose of the invention]

The present invention was made to solve the drawbacks and problems of conventional lighting devices for high-pressure discharge lamps such as high-pressure sodium lamps and metal halide lamps. In a lighting device for a high-pressure discharge lamp connected between electrodes, this high-pressure discharge lamp increases the frequency of pulse voltage generated by the opening/closing operation of a glow switch per cycle to increase the pulse energy and enable easy and reliable lighting. The purpose is to provide a lighting device for electric lights.

[Summary of the invention]

The present invention provides a lighting device for a high-pressure discharge lamp in which a series circuit of a glow switch and a current limiting resistor is connected in parallel between a pair of main electrodes of an arc tube, and the main electrode is connected to a power source via a choke coil type ballast. , the closing temperature of the bimetallic switching contact is 25
A growth inch of 0°C or higher is used, and the value of the current limiting resistor is such that the switching current of the growth inch is 0.1.
-0.2A, and increases the pulse energy based on the pulse generation frequency and pulse peak value to easily and reliably light the high pressure discharge lamp.

[Principle and Examples of the Invention]

Prior to detailed description of the present invention, the principle of the present invention will be explained first.

In the high-pressure discharge lamp lighting device shown in Figure 1, in order to reliably light the discharge lamp, it is said that it is necessary to apply a high-voltage pulse of IKV or higher, as described above. The value of current resistance is designed to be as small as possible without causing damage to the opening/closing contacts of the growth inch or short circuit of the choke coil type ballast, and is usually 100 to 1000 Ω (especially about 300 to 650 Ω). is set in the range.

However, the present inventors used a glow switch whose bimetallic switching contact has a closing temperature of 250°C or higher, and furthermore, the value of the current limiting resistor connected in series with the glow switch was 1.
It has been discovered that when the switching current exceeds 0.000Ω and the switching current is reduced to 0.2A or less, the pulse generation mode changes significantly. In other words, when the current limiting resistance value is increased to 1000 Ω or more, the pulse voltage becomes less than IKV, but the frequency of pulse generation increases extremely.
Comparing the pulse generation frequency when it is 200Ω, it is 12
When set to 00Ω, it is approximately 150 times that of 300Ω,
Nearly 40 pulses over almost the entire half cycle (pulse width 20 to 50 μSec + pulse height 700 V)
It was found that because of this, the pulse energy increases significantly even though the pulse voltage decreases.

In addition, the frequency of pulse generation peaks when the current limiting resistance is set to about 1300 Ω, and when it is increased beyond that, the frequency of pulse generation tends to decrease again. When it becomes 2000 Ω or more, the switching current becomes less than 0.1 A, and the pulse It was found that as the frequency of occurrence decreased, the pulse height also decreased and the pulse energy decreased rapidly.

Therefore, in discharge lamps such as high-pressure discharge lamps such as metal halide lamps, starting energy, that is, pulse energy, plays a more important role than pulse voltage at the time of starting.
It was confirmed that starting performance is improved when the current limiting resistor is set to 1000Ω to 2000Ω and the switching current is set to 0.1 to 0.2A.

In addition, in order to obtain multiple pulses when the current limiting resistance is increased as described above, a growth inch is constructed by placing a U-shaped bimetal 12 facing a rod-shaped electrode 11 made of Fe, etc., as shown in FIG. Glow switch 13 for conventional fluorescent lamps
As shown in FIG. 3, a switching contact 15 made of a large mass such as tungsten is provided at the tip of the bimetal 14, and the closing temperature of the switching contact 15 is set to 250°C. It has been found that it is necessary to use the glow switch 17 described above. Note that the pressure of the enclosed rare gas is preferably in the range of 15 to 25 torr.

The reason for using the glow switch configured as described above is as follows. That is, in the operation of a glow switch in a lighting device, one or both opposing bimetals are heated by the generation of glow discharge, and the bimetals are displaced until the opening/closing contacts come into contact. When the switching contacts make contact, a current limited by the series current limiting resistor flows, but the glow discharge stops, the bimetal temperature decreases, and the bimetal switching contacts open again. At this time, the magnitude of the switching current and
A pulse voltage is generated between the ballast coils, which is determined by the current interruption speed and the inductance of the choke coil ballast.

As mentioned above, in order to generate a large number of pulses per cycle, it is necessary to open and close the bimetallic switching contacts at high speed. Various factors such as bimetal, contact material, discharge gas, and switching current are related to this, but the closing temperature and switching current of the bimetal switching contact have a particularly large influence. First, for bimetals, the cooling rate must be increased by increasing the closing temperature.

Figure 4 shows glow switches with various closing temperatures filled with 17 torr of Ne-Ar gas, a single choke coil type ballast for mercury lamps (for 400 W), and a 1200
200Ω and through a current limiting resistor with a resistance value of 1500Ω
(2) It is a diagram showing the results of measuring the relationship between the average pulse generation frequency and the closing temperature of a bimetal switching contact when connected to a power source. As is clear from this figure, the current limiting resistance is 120
It can be seen that in both cases of 0Ω and 1500Ω, when the closing temperature of the bimetal switching contact is set to 250° C. or higher, the frequency of pulse generation increases rapidly. Therefore, the bimetal for bimetal switching contacts has a high closing temperature, 250
℃ or higher must be selected.

Next, as for the contact material, a weld-resistant material such as tungsten is desirable because welding of the contact slows down the opening/closing operation. Furthermore, since the increase in contact temperature caused by the discharge current between the contacts also slows down the opening/closing operation, it is preferable to use contacts that have a large thermal capacity, that is, a large mass.

Regarding the sealed discharge gas, Ar gas, Ne gas, 1!
E-gas etc. can be used alone or in combination. However, when the discharge resistance of the glow inch increases, the glow discharge current decreases due to the voltage drop caused by this resistance, the glow discharge time (Tg) of the glow switch becomes longer, and the starting time becomes slower. must be increased to increase the glow discharge current. 200
When a single choke ballast is used with a V commercial power source, in order to keep the glow discharge time Tg within about 10 seconds, the filled gas pressure needs to be 15 torr or more. However, if the pressure of the filled gas exceeds 25 torr, the pulse voltage will drop and the starting performance will deteriorate, so it is necessary to keep it below 25 torr.

Regarding the switching current, it is an important requirement to increase the frequency of pulse generation as described above, and
．． It is necessary to set it to 1-0.2A.

As described above, in order to increase the number of pulse generation per cycle and the pulse energy based on the pulse peak value, the present invention uses a growth inch whose bimetal switching contact has a closing temperature of 250°C or higher, and controls the switching of the glow switch. The value of the current limiting resistor is set so that the current is 0.1 to 0.2 A, and the discharge lamp is easily and reliably lit.

Next, examples of the present invention will be described. First, an embodiment in which the present invention is applied to the high pressure discharge lamp lighting device shown in FIG. 1 will be described. As the arc tube 1, a tube 4 containing sodium iodide and scandieum iodide along with mercury and a rare gas is used.
A 00W metal halide lamp arc tube is used. As the glow switch 5, as shown in FIG. 3, a pair of electrodes each having a bar-shaped tungsten contact at the tip of a bimetal are disposed facing each other, and a Ne--Ar mixed gas of 20 torr is sealed therein. In addition, the current limiting resistor 6 is 1200
A carbon film resistor of Ω is used, and the auxiliary electrode 4 is connected to the main electrode 3 through a high resistance of 30 Ω. Then, these are sealed in an outer tube and connected to a power source via a 400W choke coil.

When a 200V commercial power supply voltage was applied to the metal halide lamp equipped with the lighting device configured as described above and observed with an oscilloscope, as shown in Figure 5, an average of pulses with a peak value of 300 to 700 V per cycle was observed. It was observed that 75 occurrences occurred, and that they occurred over the entire half cycle. When this lighting device was used to repeatedly light 20 lamps 10 times each, there were no failures.

In addition, the current limiting resistance is 1000Ω, 1300Ω, 1
500Ω.

When we performed similar observations and repeated lighting tests by changing to 1800Ω and 2000Ω, similar results were obtained as shown in Table 1, and the number of failures was zero.Next, we will discuss these examples. In order to compare with
When the lighting operation was performed at 00Ω, the frequency of pulse generation was extremely reduced to about 0.5 pulses per IHz as shown in Figure 6, and the pulse height value was 1800Ω as shown in Table 1. It becomes about V, but the pulse energy is small, making starting uncertain, and 20 lights.

In the 10 repeated lighting tests, a total of 15 failures occurred. This is because the switching current is as large as 0.67 A, and the bimetal is further heated due to heating due to the contact resistance of the contact when the bimetal is closed, so that the bimetal operation becomes slow.

Next, when the current limiting resistance was set to 900Ω, the switch notching current was 0.22A, the heating of the contact due to contact resistance was reduced, and the bimetal operation was accelerated, so the first
As shown in the table, the pulse generation frequency is as high as 30 pulses/11z. However, there are some variations in pulse generation, for example, pulse generation stops for one to several cycles, and the pulse peak value is 800V, and the starting performance is considerably improved compared to the former, but in the repeated lighting test, two A failure occurred.

Furthermore, when the current limiting resistance was significantly increased to 2100Ω, the bimetal operation became slow again due to the decrease in glow discharge current, the pulse generation frequency decreased slightly, and the pulse peak value also decreased to below 500Ω. As a result, starting performance deteriorated, and in repeated lighting tests, the lights failed three times, making starting uncertain.

Table 1] 6 □Nyon FIG. 7 is a graph showing the pulse generation frequency a and the pulse peak value with respect to the switching current in Table 1.

In the above embodiment, the present invention was applied to the lighting device shown in FIG.
A series circuit of a diode D and a capacitor C is further connected in parallel between the main electrodes, and an auxiliary electrode 4 is connected to the connection point of the diode D and the capacitor C via a resistor 8. Of course, the present invention can also be applied to a lighting device that applies voltage, and the starting performance can be further improved.

In addition, in the above embodiment, the metal halide lamp was used as a commercial
Although a lamp started by a 0V power supply voltage has been shown, the present invention can of course be applied to other high pressure discharge lamps, such as high pressure sodium lamps.

〔Effect of the invention〕

As described above based on the embodiments, the present invention uses a bimetal switching contact with a closing temperature of 250°C or higher as a glow switch of a lighting device, and a current limiting resistor with a switching current of 0.1 to 0. Set it to 2A,
Since the structure is configured to increase the frequency of pulse generation, the pulse energy can be increased with a simple structure, and the high-pressure discharge lamp can be lit reliably.

Furthermore, since the switching current is small, there is little wear and tear on the contacts of the glow switch, and the temperature increase due to contact resistance is also small, so the glow switch can be made smaller and have a longer life.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a general configuration example of a high pressure discharge lamp lighting device using a glow switch, Fig. 2 is a diagram showing a conventional glow switch for fluorescent lamps, and Fig. 3 is a diagram showing a conventional glow switch for a fluorescent lamp. FIG. 4 is a diagram showing a configuration example of a glow switch. FIG. 4 is a diagram showing the relationship between the pulse generation frequency and the closing temperature of the bimetal switching contact of the glow switch. FIG. A diagram showing one aspect, FIG. 6, is
FIG. 7 is a diagram showing the pulse generation mode in a comparative example, FIG. 7 is a diagram showing the correspondence between pulse generation frequency and pulse peak value with respect to switching current, and FIG. 8 is another example of a lighting circuit to which the lighting device of the present invention is applied. FIG. In the figure, 1 is an arc tube, 2.3 is a main electrode, 4 is an auxiliary electrode, 5 is a glow switch, 6 is a current limiting resistor, 7 is a bimetal switch, 8 is a coupling resistor, I4 is a bimetal, and 15 is a tungsten contact. show.

Claims (1)

[Claims] A bimetal switching contact is used in a high-pressure discharge lamp lighting device in which a series circuit of a glow switch and a current limiting resistor is connected in parallel between a pair of main electrodes of an arc tube, and the main electrode is connected to a power supply via a choke coil type ballast. A glow switch with a closing temperature of 250°C or higher is used, and the resistance value of the current limiting resistor is
The switching current of the glow switch is 0.1 to 0.
A high pressure discharge lamp lighting device characterized by being set to 2A.