JP3143984B2 - High pressure discharge lamp lighting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure discharge lamp in which two arc tubes are accommodated in an outer tube and a lighting device therefor.

[0002]

2. Description of the Related Art In a high-pressure metal vapor discharge lamp such as a high-pressure sodium lamp or a metal halide lamp, the internal pressure of the arc tube becomes 1 atm or more during operation. It is necessary to wait for the internal pressure to drop due to aggregation of the mercury and the encapsulated luminescent metal. For example, in the case of a high-pressure sodium lamp having an external starter, the restart time must be about 1 minute, and in the case of a metal halide lamp, it must wait for more than 10 minutes. You have to wait a few more minutes.

[0003] Therefore, for example, in the case of a momentary power failure, in the case of an incandescent lamp or a fluorescent lamp, the lamp is immediately turned on, but in the case of the high-pressure metal vapor discharge lamp, it is necessary to wait 10 minutes or more until full power is exhibited. Not road lighting,
It is inconvenient when used for lighting in tunnels.

[0004] In order to improve this, USP 4,287,
As described in the specification of Japanese Patent No. 454, a high-pressure sodium lamp in which two arc tubes are accommodated in an outer tube and these arc tubes are electrically connected in parallel has been proposed.

[0005] In the case of such a lamp, one of the arc tubes is lit during normal operation, and is turned off by a momentary power failure, and when the power failure is resolved, the other arc tube having a low internal pressure is lit. In this case, the other arc tube is preheated when the one arc tube is turned on, and the internal pressure slightly increases, so that a stable lighting state is reached in a few minutes.
Therefore, the restart time is extremely short, which is advantageous for the above-described road lighting and tunnel lighting.

In addition, such a lamp has a long lamp life because one of the arc tubes is turned on even if one of the arc tubes is difficult to light. The lamp life is twice as long as that of the lamp. By the way, the lamp in which the two arc tubes are connected in parallel to the outer tube and housed as described above is lit from the arc tube which is easier to start when starting at a normal room temperature. In other words, the two arc tubes have a slight variation in the starting voltage due to manufacturing variations,
The arc tube with the lower starting voltage starts. For this reason, in a normal start, the arc tube on the side that is easier to start always starts off-center.

[0007] That is, one of the two arc tubes, which is easy to start, starts intensively at each normal start, and the frequency of use of the arc tube increases, so that sodium disappears only in this arc tube. , Causing an increase in lamp voltage and early deterioration.

When this arc tube becomes unusable, the other arc tube starts and lights up. However, in this state, instantaneous relighting cannot be expected, and the intended function of this type of lamp is lost. I will.

[0009] The reason why one of the arc tubes started in one direction becomes inoperable is almost dominated by an increase in the lamp voltage. Therefore, in the latter half of the life of this type of lamp, one of the arc tubes causing the above-mentioned extinguishment is lost. Is turned on first, and when this arc tube goes out, it is switched to the other arc tube and turned on. During such an extinguishing process, one of the arc tubes leaks, so that noble gas is contained in the outer tube. Leaks, the starting pulse is absorbed by the rare gas, and the other arc tube cannot be started, or even if it starts, the temperature of the arc tube does not rise due to the heat conduction of the leaked rare gas, and the lamp voltage rises. And efficiency is reduced.

[0010]

In order to solve this problem, the two arc tubes are provided with a starting auxiliary conductor to which opposing potentials are applied, so that the two arc tubes have different discharges for positive and negative potentials. It has a starting characteristic. In this state, when positive and negative pulses are simultaneously applied from the outside, the two arc tubes are lit at substantially the same ratio, and the life of the lamp is substantially doubled. However, when the lighting probabilities of the two arc tubes were examined under various conditions in the above-described lighting device, the length of the cable line connected between the lamp and the ballast was extremely short and / or the pulse height was high. It was found that when the temperature was close to the upper limit of the discharge starting voltage of the arc tube, one of the arc tubes tended to light up.

Therefore, it is an object of the present invention to make the two arc tubes start at a half rate, prevent the arc tube on one side from being biased, and provide an instantaneous relighting function for a long time. An object of the present invention is to provide a high-pressure discharge lamp lighting device that can be maintained throughout.

[0012]

According to the present invention, two luminous tubes which are started by application of a high-voltage pulse are accommodated in an outer tube in a state where these luminous tubes are electrically connected in parallel. Each of the tubes is a high-pressure discharge lamp having a proximity conductor for assisting starting, and a high-pressure discharge lamp lighting device including a current-limiting element for lighting the high-pressure discharge lamp. It is characterized in that the polarities are different from each other, and the impedance component constituting the current limiting component is divided into two and connected to two lines for power supply.

[0013]

In a high-pressure discharge lamp provided with a proximity conductor for assisting starting along an arc tube, applying a pulse to the opposite side of the proximity conductor is lower than applying a pulse to the proximity conductor. It is known that a discharge is started at a time.
This is because the provision of the proximity conductor changes the potential distribution in the discharge space, causing a large potential gradient locally, which makes it easy to cause discharge breakdown. Therefore, it is expected that the instantaneous potential distribution generated at the time of pulse application is naturally different from that created by a static electric field. In such a state, it has been found that the potential distribution of the arc tube involves not only the arrangement of the adjacent conductors but also the impedance component of the current limiting element connected to the outside.

According to the configuration of the present invention described above, if the AC pulse power source is used as a power source and the pulse generated by the starting pulse generator has a positive and a negative probability of 50% each, it is close to each arc tube. Since the polarity of the adjacent conductors provided is different from each other and the current limiting element is divided into two and connected to the two lines of the power supply, the above-mentioned probability is increased by 50% for each pulse.
The rate at which the arc tubes are started is also 50%.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to one embodiment shown in FIGS. FIG. 1 shows the configuration of the apparatus 2
FIG. 2 is a front view of a 50 W high-pressure sodium lamp, and FIG. 2 is a circuit configuration diagram shown together with a lighting circuit.

In FIG. 1, reference numeral 1 denotes an outer tube of a high-pressure sodium lamp, which is made of hard glass or the like, and has a BT type having a base 2 attached to one end. Base 2 is shell 3
And a screw-type base having an eyelet terminal 4. The outer tube 1 contains two arc tubes 5a and 5b.

Each of the arc tubes 5a and 5b has an end cap made of alumina ceramic as a closing wall at the end of a bulb made of a ceramic tube made of polycrystalline alumina or monocrystalline alumina having an inner diameter of 7.2 mm and a total length of 91 mm. Airtightly joined, for example to these end caps
Electrode 6 coated with Ba-Ca-W-based oxide emitter
(Shown in FIG. 2) is sealed. The electrodes 6 are connected to the conductive structures 7, and these conductive structures 7 project from the end caps. For example, 4.5 mg of sodium, 25.5 mg of mercury, and 150 ton of xenon gas are sealed in such arc tubes 5a and 5b.

1 are electrically and mechanically connected to valve holders 8a and 8b. In this case, the two arc tubes 3a and 3b are
For example, they are juxtaposed or intersected at intervals of 3 mm. Both ends of the valve holders 8a and 8b are connected to support wires 9a and 9b, respectively. The lower conductive structure 7 is supported by an insulating holder 10 and both ends of the insulating holder 10 are supported by support wires 9.
a, 9b.

The support wires 9a and 9b are made of conductive wires, and their upper ends are mutually connected by an insulating bridge 11. These upper ends are locked to the top of the outer tube 1 via elastic plates 12a and 12b. Have been.

The lower ends of the support wires 9a and 9b are welded to sealing support lines 13a and 13b, and these sealing support lines 13a and 13b are sealed to the stem 14 of the outer tube 1. These sealing support wires 13a and 13b are connected to the external conductor 1
It is connected to the shell 3 of the base 2 and the eyelet terminal 4 by 5a and 15b.

Then, outside each of the arc tubes 3a and 3b,
Proximity conductors 17a, 17 for starting assistance along the axial direction
b is provided. These proximity conductors 17a and 17b are arranged on opposite sides of a plane formed by the two arc tubes on the outer surface of each arc tube 3a and 3b. One end is rotatably supported by the valve holders 8a and 8b, and the other end is welded to the bimetal pieces 18a and 18b. These bimetal pieces 18a and 18b are welded to support wires 9a and 9b, respectively. In addition,
19 indicates a getter. Also, the inside of the outer tube 1 is 1/1000
It is kept at a high vacuum of about 0. The lamp having such a configuration is used by being connected to the lighting circuit shown in FIG.

The lighting circuit includes a current limiting element 21 connected to an AC power supply 20 and a starting pulse generator 22 which is publicly known and whose detailed configuration is omitted. The current limiting element 21 and the starting pulse generator 22 are configured as dedicated devices outside the lamp. The current limiting element has the same impedance
It comprises choke coils 21A and 21B having a dance and a capacitor 21C for power factor improvement. Choke coil 2
Reference numerals 1A and 21B are inserted in series into two lines for power supply.

When the lamp is started, such a lighting circuit, as shown in FIG.
The pulses P generated by the starting pulse generator 22 are superimposed on each other and applied to the lamp. This pulse has a peak width of 90% of about 2 μs.

In such a configuration, before the lamp is started, the adjacent conductors 17a and 17b are respectively cooled by the operation of the bimetal pieces 18a and 18b because the lamp is cold before the lamp is started.
a, 5b are approaching.

When the lamp is started, the starting pulse generator 22 of the lighting circuit is applied to the AC voltage V from the AC power source 20 as shown in FIG.
Are superimposed and applied to the lamp. In this case, a high voltage pulse is applied to each of the positive and negative AC voltages, that is, a starting pulse is generated alternately every half cycle.

In the lamp, the arc tube has a property of easily starting when the electrode facing the adjacent conductor has a positive voltage with respect to the adjacent conductor. For example, the positive electrode is connected to the eyelet terminal 4 of the base 2. When a pulse is applied, a positive high voltage is applied to the electrode facing one of the adjacent conductors 17a, so that the arc tube 5a approaching the electrode is activated. Conversely, when a positive pulse is applied to the shell 3 of the base 2, the other adjacent conductor 17b becomes negative, and the arc tube 5b to which it is approaching starts.

As described above, the proximity conductors 17a and 17b
The probability that a positive pulse is applied to each of the arc tubes is 50%, so that the probability that each of the arc tubes 5a and 5b is started at the time of starting is 50%. This ratio is equalized as the number of times of lighting increases, so that one of the arc tubes does not start eccentrically and intensively.

Therefore, it is possible to prevent the frequency of use of one of the arc tubes from being increased, and to eliminate problems such as an increase in the lamp voltage due to the disappearance of sodium in the one arc tube and an early deterioration. Thus, the life is doubled as compared to a lamp containing substantially one arc tube.

Further, when one of the arc tubes is turned on, it is turned off by a momentary power failure, and when this power failure is resolved,
The arc tube with the lower pressure, which was not illuminated until then, is illuminated. In this case, the other arc tube is preheated when the one arc tube is turned on, and the internal pressure slightly increases, so that a stable lighting state is reached in a short time. Therefore, the restart time is extremely short, and if used for road illumination or illumination in a tunnel, the brightness is restored in a short time, so that safety can be improved.

When the arc tube is lit, the bimetal pieces 18a and 18b are heated and deformed, and the adjacent conductors 17a and 18b are deformed.
17b is separated from the arc tubes 5a and 5b, respectively. Therefore, the light emitted from the arc tube is transmitted to the proximity conductors 17a and 17b.
Is reduced.

The lighting device thus constructed was compared with a lighting device in which the same high-pressure discharge lamp was connected to a choke coil only on one line side of the power supply. The same starting pulse generator was used, and the combined impedance of the two choke coils was the same as that of the choke coil inserted only on the one-wire side. The results are shown in FIG. 4 with the power supply at 90% of the rating. The numbers indicate the rate at which one arc tube was lit. The average value of the minimum values of the discharge starting voltages of the two arc tubes was 2000V.

As described above, the lighting ratio of the two arc tubes can be made almost equal by inserting the choke coil into two lines. This effect is the WL of the lamp
It has nothing to do with the size or size of the enclosure. In addition, not only a choke coil but also an impedance component composed of a series circuit of a choke coil and a capacitor were similarly obtained. Further, it is desirable that the division be performed so that the impedances are equal, but there is no problem even if there is a deviation of about 10%. Further, the present invention is not limited to a high-pressure sodium lamp, but can be implemented with a metal halide lamp, a high-pressure mercury lamp, or the like.

Then, the proximity conductor of the present invention is disposed along the axial direction on the outer surface of the arc tube so that the bimetal pieces 18a,
It is not limited to the one that comes into contact with and separates from the arc tube by the operation of 8b, but may be a spirally wound around the outer surface of the arc tube.

Further, when a metal member such as a support wire for supporting the arc tube is in proximity to the arc tube,
The metal member such as the support wire may be used also as the proximity conductor, and in this case, a separate proximity conductor is not required.

[0035]

As described above, according to the present invention, the pulse generated by the starting pulse generator using an AC power supply has a positive and a negative probability of 50% each, and therefore, is provided for each arc tube. If the polarity of the adjacent conductors is made different from each other and the current-limiting element for lighting is divided and connected to each of the two lines of the power supply, the two arc tubes are started by a pulse having a probability of 50%. The ratio is also 50%. For this reason, it is prevented that only one of the arc tubes is illuminated in one direction, the frequency of use of both arc tubes becomes uniform, and problems such as early deterioration of one arc tube are eliminated, and the life is reduced by 2
As a result, the function of instantaneous relighting can be reliably exhibited until the end of the life.

[Brief description of the drawings]

FIG. 1 is a front view showing an entire high-pressure sodium lamp according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram.

FIG. 3 is a cycle diagram of a pulse generation state.

FIG. 4 is a diagram comparing a lighting device in which the same high-pressure discharge lamp as the lighting device according to the present invention is connected to a choke coil only on one line side of a power supply.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer tube, 5a, 5b ... Arc tube, 6 ... Electrode, 9a, 9b
... support wires, 17a, 17b ... close conductors, 22 ...
Start pulse generator.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-49-17077 (JP, A) JP-A-56-93260 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 61/54 H01J 61/56

Claims (2)

(57) [Claims] 1. An outer tube contains two arc tubes, which are started by application of a high-voltage pulse, in a state where they are electrically connected in parallel, and each of these arc tubes is provided for assisting in starting. In a high pressure discharge lamp lighting device comprising a high pressure discharge lamp having a proximity conductor and a current limiting element for lighting the same, the proximity conductors provided in each of the arc tubes have different polarities from each other, and A high-pressure discharge lamp lighting device characterized in that the impedance component constituting the element is divided into two substantially equal parts and connected to two power supply lines. 2. The high pressure discharge lamp lighting device according to claim 1, wherein said impedance component comprises an inductance component.