JPS6314461B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal vapor discharge lamp that uses a starting voltage obtained by superimposing a peak starting voltage on a sinusoidal voltage and is started using a nearby conductor provided outside the arc tube.

For example, in a high-pressure sodium lamp, an arc tube bulb made of translucent polycrystalline or single crystal, such as alumina ceramic, is sealed at both ends with caps made of niobium or tantalum, etc., and a main electrode is attached to these caps. Mercury and sodium are sealed as luminescent metals in a tube bulb, and xenon gas is further sealed as a starting rare gas to form an arc tube, and this arc tube is housed in an outer tube with a cap at one end. has been done. This type of high-pressure sodium lamp has extremely high light efficiency compared to mercury lamps, etc., so it is often used in various light sources as a power-saving light source.However, since this type of high-pressure sodium lamp has a high starting voltage, it has a high voltage compared to the sine wave voltage of 200V commercial voltage. It is necessary to superimpose a peak starting voltage using a special means of generating pulses for starting. For example, a device containing 10 to 20 torr of xenon gas as a starting rare gas requires a starting voltage of 1500 to 2500V. Therefore, the biggest problem with this type of lamp is how to lower the starting voltage, and various improvements have been made in the past. For example, xenon, which is used as a rare starting gas, contributes to increasing the starting voltage, so if a Penning gas such as a neon-argon mixture is used instead of xenon, the starting voltage can be reduced to about 500V. It is something that can be done. However, since the xenon gas greatly contributes to the improvement of light efficiency, it is not a good idea to use Penning gas instead of xenon gas because it will undermine the greatest advantage of this type of high-pressure sodium lamp. . Therefore, it is possible to use an auxiliary electrode close to the main electrode, but this type of arc tube is made of alumina ceramic, and it is almost impossible to install an auxiliary electrode inside the bulb due to processing and longevity considerations. be. For this reason, in recent years, a proximate conductor for starting is brought into contact with the outside of the arc tube, and the potential difference generated between this proximal conductor and the main electrode is used to facilitate the start of discharge, thereby increasing the starting voltage. Measures have been developed to reduce the Using a nearby conductor in this way greatly contributes to lowering the starting voltage, and in addition to this method, starting is made easier by superimposing a peak starting voltage on the sinusoidal voltage mentioned above. Uses xenon gas and produces hundreds of
Encapsulation at torr pressure also provides a lamp with even higher light efficiency than conventional lamps.

However, if you connect the lighting with the nearby conductor in contact with the arc tube, the light emitted from the arc tube will not only be blocked by the nearby conductor and cause shadows on the nearby conductor, but also the nearby conductor that is in contact with the arc tube will Sodium ions inside the bulb are attracted and react with the alumina ceramic, corroding the bulb wall and causing early blackening, and deterioration such as deformation of the adjacent conductor due to heat from the arc tube.

For this reason, the adjacent conductor is made of a heat-responsive metal such as a bimetal piece, and at room temperature before lighting, the adjacent conductor made of the bimetal piece is in contact with the arc tube, and as the temperature rises after lighting, the bimetal piece changes. A device that uses thermal deformation to separate from the arc tube has been developed.

However, in the case of such a structure, the thermally responsive metal consisting of a bimetallic piece is formed in the form of a band, and even if it is separated from the arc tube during lighting, a shadow will still occur because of the large light-shielding area. From this, it is conceivable to form the proximal conductor into a rod or foil-like elongated body, and arrange this elongated proximal conductor in the axial direction, that is, the longitudinal direction, of the arc tube. Such a long proximal conductor has a structure in which it is supported by a thermally responsive metal such as a bimetal in order to keep it away from the arc tube during lighting, but it would be expensive to support both ends of the elongated proximal conductor with a bimetal. The number of bimetals used has increased, and the adjacent conductor itself expands in the longitudinal direction due to the heat of the arc tube, causing problems such as bending and undesired deformation of the bimetal.

The present invention was developed based on these circumstances, and its purpose is to reduce the number of expensive thermally responsive metals used, and to reduce the thermal expansion and contraction of long neighboring conductors in the longitudinal direction. It is an object of the present invention to provide a metal vapor discharge lamp that can absorb this and prevent deformation, thereby ensuring reliable operation of the adjacent conductor.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.
This will be explained with reference to the figures.

The drawing shows a high-pressure sodium lamp rated at 360W, with reference numeral 1 indicating an outer tube, 2 a cap attached to one end of the outer tube 1, and 3 an eyelet terminal provided on the cap 2. A stem 5 is attached to the end of the neck portion 4 of the outer tube 1.
is sealed, and this stem 5 has an internal conductor 6.
a and 6b are sealed. One internal conductor 6a
is connected to the base 2, and the other internal conductor 6b is connected to the eyelet terminal 3. These internal conductors 6a and 6b are each provided with a conductive support 7 that also serves as a part of the arc tube support.
a and 7b are welded together, and a support 7a connected to the cap 2 via an internal conductor 6a extends inside the outer tube 1 toward the other end, and is elastically attached to a small diameter top portion 8 formed at the tip of the outer tube 1. It is landed via the plates 9,9. Conductive holders 10, 10 are attached to these supports 7a, 7b, respectively. In this case, one end of one holder 10 is electrically connected to the other support 7b, and the other end is supported by one support 7a via an insulating glass tube 11. A light emitting tube 12 is placed between the holders 10 and 10 so as to be positioned on the tube axis of the outer tube 1 along the vertical direction in the drawing. This arc tube 12 consists of an arc tube bulb 13 made of an alumina ceramic tube with an inner diameter of 8 mm and a total length of 114 mm.
The main electrode 1 is connected to these caps 14, 14.
5a and 15b are attached to face each other. These main electrodes 15a, 15b are electrically connected to the supports 7a, 7b via holders 10, 10. In the arc tube bulb 13, a predetermined amount of mercury and sodium are filled as luminescent metals, and for example, as a starting rare gas.
It is filled with 300 torr of xenon gas. A proximity conductor 16 is provided on the outside of such an arc tube 12. The proximal conductor 16 is made of a fusible metal such as tungsten, molybdenum, tantalum, etc., and has a long rod-like or foil-like shape, and in this embodiment, a molybdenum wire with a wire diameter of 0.5 mm is used. This proximity conductor 16 is arranged along the longitudinal direction of the arc tube 12 in contact with or very close to the outer surface of the arc tube bulb 13. And this proximity conductor 1
One end of 6 located on the base 2 side is close to the main electrode 15b located on the base 2 side, and the tip of a thermally responsive metal member, that is, a bimetal 17, is welded to this one end. The base end of this bimetal 17 is welded to a support 7a connected to the other main electrode 15a opposite to the main electrode 15b located on the base side. In addition, the proximity conductor 16
The other end located on the valve top side is support 7.
It is supported by the distal end portion of the outer tube 7a, for example, a portion 7aa disposed perpendicular to the tube axis of the outer tube.
This support means may be welded or the like, but in the case of this embodiment, as shown in FIG. , this locking tool 18 and support 7a
The other end of the proximal conductor 16 is loosely inserted into a through hole 19 formed between the tip portion 7aa of I'm starting to be able to do it.

Furthermore, an insulating base 20 is disposed in the outer tube 1 adjacent to or inside the neck part 4, and a filament 21 as a resistance heating element is connected to the anchor wire 22 on this insulating base 20. A thermally responsive switch, such as a bimetallic switch 23, which is supported and attached to the filament 21 and is activated by the heat of the filament 21, is provided. The filament 21 is placed on the insulating base 20 so that it is bent in a W-shape to form a planar heating element.
The thermally responsive movable piece 24 of the bimetal switch 23 is arranged to face the filament 21, and the fixed contact rod 2 is supported at room temperature before lighting.
5 has been contacted. The filament 21 and the bimetal switch 23 are connected in series with each other as shown in FIG.
A and 7b are electrically connected and connected in parallel to the arc tube 12.

Such high pressure sodium lamps are equipped with ballast 2
The ballast 26 is connected to a 200V commercial power supply via a 200V commercial power source, and the ballast 26 is a mercury lamp ballast simply equipped with a chiyoke coil 27 as shown in FIG. In this case, the chiyoke coil 27 of the ballast 26
The side is connected through the eyelet terminal 3 to a main electrode 15b located close to the base 2 side.

The operation of the embodiment having such a configuration will be explained.

Before starting, the inside of outer tube 1 is at room temperature, so
The proximal conductor 16 is in contact with the outer surface of the arc tube pulp 13, and the thermally responsive contact piece 24 of the bimetallic switch 23 is in contact with the fixed contact rod 25, so that the bimetallic switch 23 is closed.

When the lamp is connected to a commercial power source through a ballast 26 as shown in FIG.
Since the filament 21 is energized, the filament 21 generates heat. Further, the proximal conductor 16 that is in contact with the outer surface of the vapor tube bulb 13 is kept at the same potential as the main electrode 15a that is separated from the cap 2 side, and the end of this proximal conductor 16 on the cap 2 side is connected to the cap 2 side. side main electrode 15b
Since the main electrode 15b is close to the main electrode 15b, a steep potential angle is generated near the main electrode 15b. Filament 21 above
As the heat builds up, the bimetal switch 23 is heated, and when the bimetal switch 23 is opened, a high voltage pulse of several thousand volts is generated. By superimposing it on the sinusoidal voltage of the power supply,
An extremely high starting voltage is applied between the opposing main electrodes 15a and 15b. At this time, the adjacent conductor 16
Since there is a large potential gradient between the main electrode 15b on the base side and the main electrode 15b on the base side, starting is performed when the above-mentioned high voltage, a starting voltage of about 2000 to 4000 V, is applied. In other words, because the kick voltage of the bimetal switch 23 is used as the starting voltage and the nearby conductor 16 creates a potential gradient, even if the lamp is filled with xenon gas of 200 torr or more, it will not be stable for normal mercury lamps. By using a power supply, it is possible to light the lamp using a commercial power supply of 200V or less.

In addition, in the wiring shown in FIG. 5, when the 27 choke coils of the ballast 26 are connected to the main electrode 15a remote from the base side through the base 2, a high starting voltage is required. This is main electrode 1
Even if a high voltage pulse is applied to the main electrode 15
This is because a large potential gradient is not formed near b.

When the lighting is stabilized after starting in this way, the temperature of the arc tube bulb 13 rises, and this heat causes the bimetal 17 provided at the end of the proximal conductor 16 on the base side to
is heated and curved as shown in the imaginary line in Figure 2. Therefore, the adjacent conductor 16 is connected to the arc tube bulb 13.
Since the sodium ions move away from the outer surface of the bulb 13, the sodium ions are not attracted to the adjacent conductor 16 and react with the alumina tube, eliminating blackening, and the proportion of light emitted from the bulb 13 being blocked is also reduced. In addition, the adjacent conductor 16 is less likely to receive the heat of the bulb 13, and thermal deterioration is also reduced. Moreover, since the proximal conductor 16 is made of a refractory metal, it will not undergo undesirable thermal deformation in the normal temperature range of the bulb 13, and can withstand long-term use. Furthermore, the proximal conductor 16 has its base end fixed to the support 7a by a bimetal 17, and the other end remote from the base is supported by the tip 7aa of the support 7a. It is economical because only one is needed. In particular, the other end of the proximity conductor 16,
Through hole 19 provided at the tip 7aa of the support 7a
Since it is loosely inserted into the proximal conductor 16, when the base end of the proximate conductor 16 is displaced in the direction of the arrow as the bimetal 17 deforms as shown in FIG. Since the adjacent conductor 16 can freely rotate within the through hole 19, generation of torsional stress is prevented. Also, the arc tube bulb 13
The adjacent conductor 16 will thermally expand in the axial direction due to the heat from the through hole 19, but since the adjacent conductor 16 within the through hole 19 can be freely displaced in the axial direction, it absorbs the thermal expansion and does not generate unreasonable stress. . Therefore, there is no undesirable deformation and the thermal responsiveness of the bimetal 17 is not inhibited, so that normal operation can be maintained for a long period of time.

For such lamps, arc tube bulb 1
Even if 300 torr of xenon gas is sealed inside 3,
It can be lit with a starting voltage of 2500V using a mercury lamp ballast 26 using a 200V commercial power supply, and after stabilizing the lighting, a high efficiency of 140ml/W can be obtained, compared to the conventional 125ml/W. Confirmed.

In addition, as a means for holding the end of the proximal conductor 16 away from the base side, that is, as a structure of a holding part that allows rotation of the proximate conductor and also allows free movement in the longitudinal direction to absorb thermal expansion and contraction. may have a configuration as shown in FIGS. 7 and 8, for example. That is, in this case, a band-shaped locking tool 70 is formed into an annular shape and welded to a portion 7ab of the support 7a that is parallel to the tube axis at the distal end portion.
By forming the through hole 71 in the 0, the center line of curvature deformation of the bimetal 17 and the center line of rotational displacement of the adjacent conductor 16 are made to substantially coincide. In this way, in addition to the same effect as described above, the adjacent conductor 16 is changed into a crank shape, so that the arc tube bulb 13 is different from the arc tube bulb 13 over substantially the entire length of the arc tube pulp 13 of the adjacent moving body 16 in the tube axis direction. They will be evenly spaced.

Furthermore, although the above embodiment describes a high-pressure sodium lamp, lamps in which the arc tube bulb is made of a translucent single crystal or polycrystalline material such as alumina or sapphire may be provided with an auxiliary electrode within the bulb. Since this is difficult, the present invention is applicable to, for example, metal halide lamps.

Furthermore, in the above embodiment, the filament 21 and the bimetal switch 23 are provided in the outer tube 1, and the high voltage pulse of the kick voltage of the bimetal switch 23 due to the heat generated by the filament 21 is superimposed on the sinusoidal voltage. As shown as a modified example circuit in FIG. 9, a chiyoke coil 81, a capacitor 82, and an appropriate electronic circuit 83 are incorporated in a ballast 80, and the ballast 80 itself generates a high-frequency peak voltage in a sinusoidal voltage. A ballast for high-pressure sodium lamps configured to generate a high starting voltage in a superimposed manner is known, and if such a ballast is used, the filament 21 and bimetallic switch 23 will not be incorporated into the outer tube 1. Even if the structure is different, it can be used in the same manner as in the above embodiment, and therefore, it is not limited to the structure in which the filament 21 and the bimetal switch 23 are housed in the outer tube 1.

As detailed above, the present invention has an elongated nearby conductor arranged along the longitudinal direction of the arc tube, and one end of the nearby conductor on the base side is connected to an electrode opposite to an electrode located on the base side. It is attached to the arc tube support member at the same potential via a thermally responsive metal member, and the other end is held in a holding part provided on the arc tube support member so as to be rotatable and freely movable in the longitudinal direction. It is what was done. Therefore, according to this method, the adjacent conductor is brought close to or in contact with the arc tube at room temperature before lighting or by the thermally responsive member, facilitating starting, and after lighting, due to the deformation of the thermally responsive member. Since at least one end of the proximal conductor is moved away from the arc tube, there is no problem such as attracting ions inside the arc tube. Since the proximal conductor is elongated and is pulled away from the arc tube during lighting, it is less likely to block light from the arc tube and no shadows will occur. In addition, when the adjacent conductor thermally expands due to heat from the arc tube, the other end of the adjacent conductor is held movably in the longitudinal direction by a holding portion provided on the arc tube support member. Therefore, the conductor expands and contracts, and the adjacent conductor is not deformed, and even if one end is twisted by the thermally responsive metal member, no torsional stress is generated. Therefore, there is an advantage that the operation of the adjacent conductor can be performed reliably.

[Brief explanation of the drawing]

1 to 6 show one embodiment of the present invention, FIG. 1 is a front view of the entire high-pressure sodium lamp, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. 4 is a top view showing the relationship between the filament and the bimetal switch, FIG. 5 is a lighting circuit diagram, FIG. 6 is a characteristic diagram showing the starting voltage, and FIGS. The drawings show a modification; FIG. 7 is an overall front view, FIG. 8 is a sectional view taken along the line - in FIG. 7, and FIG. 9 is a circuit diagram of still another modification. DESCRIPTION OF SYMBOLS 1... Outer tube, 2... Cap, 7a, 7b... Support (luminous tube support member), 12... Luminescent tube, 13
...Bulb, 15a, 15b...Main electrode, 16...
...Proximity conductor, 17... Bimetal (thermally responsive metal member), 19... Through hole, 21... Filament (heating resistor), 23... Bimetal switch (thermally responsive switch).

Claims (1)

[Claims] 1. A light emitting tube made of a translucent polycrystal or single crystal with a pair of opposing electrodes provided at both ends and at least a luminescent metal and a rare gas sealed inside.
In a discharge lamp that is installed in an outer bulb with a cap attached to one end and is lit by superimposing a peak starting voltage on a sinusoidal voltage between the opposing electrodes at the time of starting, a long length along the longitudinal direction of the arc tube is used. One end of this proximity conductor located on the base side is attached via a thermally responsive metal member to an arc tube support member having the same potential as the electrode opposite to the electrode located on the base side, and the other The end is held rotatably and movably in the longitudinal direction by a holding part provided on the arc tube support member, and this proximal conductor is close to or in contact with the arc tube at room temperature, and at least the cap side electrode is held during lighting. A metal vapor discharge lamp characterized in that it moves away from the outer surface of a neighboring arc tube.