JPS6328522Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a metal vapor discharge lamp which uses a starting voltage obtained by superimposing a peak starting voltage on a sinusoidal voltage and which 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. It is configured. 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 since this type of arc tube is made of alumina ceramic, it is almost impossible to install an auxiliary electrode inside the bulb due to processing and longevity considerations. . 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 main stage, starting is made easier by superimposing the peak starting voltage on the sinusoidal voltage mentioned above. Conversely, by using xenon gas and enclosing it at a pressure of several hundred torr, a lamp with even higher light efficiency than conventional lamps can be obtained.

However, if you connect the lighting with the nearby conductor in contact with the arc tube, not only will the light emitted from the arc tube be blocked by the nearby conductor, creating a shadow on the nearby conductor, but also the nearby conductor that is in contact with the arc tube will As a result, sodium ions inside the bulb are attracted and react with the alumina ceramic, corroding the bulb wall and causing early blackening, and causing problems such as the nearby conductor itself being deformed by the heat from the arc tube. For this purpose, both ends of adjacent conductors arranged along the longitudinal direction of the arc tube are fixedly supported by thermally responsive metal members, such as bimetals, and the thermally responsive metal members are thermally bent by the heat from the arc tube during lighting. Accordingly, means have been developed to move the adjacent conductor away from the arc tube during lighting. With this method, the nearby conductor separates from the arc tube during lighting, which prevents the bulb from blackening or cracking. However, when the lamp is lit for a long time, the thermally responsive members fixed at both ends cause the close conductor to separate from the arc tube due to the high temperature during lighting. Thermal expansion causes thermal deformation in addition to the necessary thermal curvature, and even when the temperature returns to room temperature, the thermal deformation remains, making it impossible for the adjacent conductor to adhere to the outer surface of the arc tube and return to its original state, reducing the starting assist function. As a result, the starting voltage became high and the lamp malfunctioned.

For this reason, the present inventor first fixed only one longitudinal end of the proximal conductor to the arc tube support member via a thermally responsive metal member, and the other end was freely held by the arc tube support member. We have proposed a device that allows thermal expansion during lighting to escape and prevents undesired deformation of thermally responsive metal members, and that this product does not deform even over a long lamp life. It is clear that However, in the above proposal, since the other end of the proximal conductor is held freely, it is difficult to maintain a constant posture of the proximal conductor, and especially during assembly, the proximal conductor is held almost the entire length of the arc tube. It was difficult to maintain a position that ensured contact over a long period of time, and there was a problem in that it required time and effort to assemble.

This idea was developed based on these circumstances, and its purpose is to ensure that the adjacent conductor comes into contact with the arc tube at room temperature, and that the adjacent conductor separates from the arc tube during lighting. Furthermore, the present invention aims to provide a metal vapor discharge lamp that can prevent undesired thermal deformation of the thermally responsive metal member, ensure reliable starting even during the life of the lamp, and improve workability during manufacturing.

The first embodiment of this invention is shown below in Figures 1 to 7.
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. Each of these internal conductors 6a and 6b is provided with a conductive support 7 that also serves as a part of the arc tube support member.
A and 7b are welded together, and the support 7a, which is connected to the base 2 via the internal conductor 6a, extends inside the outer tube 1 toward the other end, and has a small-diameter top portion 8 formed at the tip of the outer tube 1. The elastic plates 9, 9 are interposed therebetween. 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.
4 and 14, and main electrodes 15a and 15b are attached to these caps 14 and 14 so as to face each other. These main electrodes 15a, 15b are connected to the supports 7a, 15 through holders 10, 10.
7b. In the arc tube bulb 13, predetermined amounts of mercury and sodium are filled as luminescent metals, and for example, 300 torr of xenon gas is filled as a starting rare gas. A proximity conductor 16 is provided on the outside of such an arc tube 12. The proximal conductor 16 is made of a hard-to-melt metal such as tungsten, molybdenum, tantalum, etc., and has an elongated rod-like or foil-like shape, and in this embodiment, a molybdenum wire with a wire diameter of 0.5 mm is used.
The proximal conductor 16 is disposed along the longitudinal direction of the arc tube 12 in contact with the outer surface of the arc tube bulb 13. One end of the proximal conductor 16 located on the base 2 side is close to the main electrode 15b located on the base 2 side, and as shown in FIG. 17
The tip is welded. The base end of this bimetal 17 is connected to the main electrode 15 located on the base side.
b is welded to the support 7a which is electrically connected to the other main electrode 15a opposite to the support 7a. Further, the other end of the proximity conductor 16 located on the valve top side is bent into a substantially crank shape to support the support 7a.
The distal end portion of the outer tube, for example, a portion 7aa disposed parallel to the tube axis of the outer tube, is freely supported. As shown in FIG. 3, this support means includes a band-shaped locking device 18 welded to the tip end portion 7aa of the support 7a, and the proximal conductor 16 is inserted into a through hole 18a formed at the tip of the locking device 18. The other end of the proximal conductor 16 is loosely inserted into the through hole 1.
It can be freely rotated and displaced in the axial direction within 8a. Further, the vicinity of the end of the proximal conductor 16 on the floating support side is pressed against another thermally responsive metal member, for example, a bimetal 19. That is, as shown in FIG. 4, the bimetal 19 has its base end welded to the support 7a, and its tip abuts the end of the proximal conductor 16. In this case, it is important to note that the tip of the bimetal 19 is not fixed to the adjacent conductor 16, but merely presses against it, so that even if the bimetal 19 deforms as the ambient temperature rises, the adjacent conductor 16 The movement of 16 is not restricted by this thermal deformation. Therefore, the adjacent conductor 16 connects the arc tube bulb 13 with bimetals 17 and 19 at both ends.
is in contact with the outer surface of the

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 2 so that it is bent in a W-shape, for example, to form a planar heating element.
The bimetal switch 23 is supported by the anchor wires 22 whose value is set to 0, and the thermally responsive movable piece 24 of the bimetal switch 23 is arranged to face the filament 21, and is in contact with the fixed contact rod 25 at room temperature before lighting. has been done. 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 bulb 13, and the thermally responsive movable piece 24 of the bimetallic switch 23 is closed in contact with the fixed contact rod 25.

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 proximate conductor 16 that is in contact with the outer surface of the arc 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. Since it is close to the main electrode 15b, a steep potential gradient is generated near the main electrode 15b. When the heat generated by the filament 21 grows and the bimetal switch 23 is opened, a high voltage pulse of several thousand volts is generated as shown in Fig. 7. By superimposing it on the sinusoidal voltage of the commercial power supply, an extremely high starting voltage is applied between the opposing main electrodes 15a and 15b. At this time, since a large potential gradient is generated between the proximal conductor 16 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 because the adjacent conductor 16 creates a potential gradient, even if the lamp is filled with xenon gas of 200 torr or more, it will not work for normal mercury lamps. By using a ballast, it is possible to light the lamp with a commercial power supply of 200V or less.

In addition, in the wiring shown in FIG.
When connected to the main electrode 15a remote from the base side, 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, 1 provided at both ends of the adjacent conductor 16 to rise.
9 is heated and bent as shown in the imaginary lines in FIGS. 2 and 4. That is, since the end of the proximal conductor 16 on the base side is welded to the bimetal 17,
When the bimetal 17 is thermally deformed, it is displaced together with the tip of the bimetal 17 and separated from the arc tube bulb 13, as shown by the imaginary line in FIG. on the other hand,
The other end of the proximal conductor 16 is not welded to the bimetal 19, and the bimetal 19 is simply pressed, so even if the bimetal 19 is curved, the proximal conductor 16 will not be welded to the bimetal 19, as shown in FIG. Does not follow bimetal 19, just bimetal 19
The only part is curved. At this time, the proximate conductor 16 separates from the arc tube bulb 13 only by the thermal curvature of the bimetal 17 at the end on the base side. Therefore, it is separated from the arc tube bulb 13 using the through hole 18a as a pivot point. In this way, the proximal conductor 16 is separated from the arc tube bulb 13, so that sodium ions are not attracted to the proximal conductor 16 and react with the alumina tube, and blackening is eliminated, and the light emitted from the bulb 13 is In addition, the proximate conductor 16 is less likely to receive heat from 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 other end of the proximity conductor 16 is connected to a support 7.
Since it is loosely inserted into the through hole 18a provided in the tip 7aa of the proximal conductor 16, as shown in FIG. Although torsional stress is applied to the conductor 16, the generation of torsional stress is prevented because the adjacent conductor 16 can freely rotate within the through hole 18a. Further, the adjacent conductor 16 will thermally expand in the axial direction due to the heat from the arc tube bulb 13, but the adjacent conductor 16 in the through hole 18a
6 can freely move in the axial direction, so it absorbs thermal expansion and does not generate undue 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.

On the other hand, when the power is turned off and the lamp is extinguished, heat radiation from the arc tube 12 is stopped, so the inside of the outer tube 1 returns to room temperature. Due to this temperature drop, the bimetal switch 23 is activated, and each bimetal 1
7 and 19 are returned to deformation as shown by solid lines in FIGS. 2 and 4, so that the proximal conductor 16 is brought into contact with the outer surface of the arc tube bulb 13. That is, since one end of the proximal conductor 16 is integrally fixed to the tip of one bimetal 17, the one end of the proximal conductor 16 follows the movement of the tip of the bimetal 17 and is returned. On the other hand, the other end of the adjacent conductor 16 is connected to the through hole 1.
Not only does it allow the bimetal 17 to move on one end side by floating within the bimetal 8a, but also by returning the other bimetal 19, the bimetal 1
9, the other end of the proximal conductor 16 is also forcibly pressed against the outer surface of the arc tube bulb 13. Therefore, at room temperature, the adjacent conductor 16 reliably contacts the outer surface of the arc tube bulb 13, so that the next start can be easily performed.

According to such a configuration, during assembly, one end of the proximal conductor 16 is connected to one bimetal 17.
Not only is the position of the adjacent conductor 16 regulated by the bimetal 17 and is welded to the bimetal 17, but also the other end is loosely passed through the through hole 18a and is pressed against the arc tube 12 by the other bimetal 19.
Therefore, the posture and position of the proximal conductor 16 can be easily regulated, making assembly easier, and high-precision assembly possible, so that the proximal conductor 16 can reliably perform its function. It will also happen.

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 140lm/W can be obtained, which is more effective than the conventional 125lm/W. Confirmed.

Note that the means for freely supporting the end portion of the proximal conductor 16 remote from the base side may be configured as shown in FIGS. 8 and 9. That is, in this case, an Ω-shaped locking tool 70 is welded to a portion 7ab of the tip of the support 7a, which is orthogonal to the tube axis, and this locking tool 70 and the portion 7ab of the support 7a are welded.
By forming a through hole 71 between them, the other end of the proximal conductor 16 is allowed to freely pass through the through hole 71.

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 can be applied 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. 10, a chiyoke coil 81, a capacitor 82, and an appropriate electronic circuit 83 are incorporated in a ballast 80, and the ballast 80 itself converts a sinusoidal voltage into a high-frequency peak voltage. A ballast for high-pressure sodium lamps is known, which is configured to generate a high starting voltage by superimposing
Even if the structure does not incorporate the filament 21 and the bimetal switch 23, it can be used in the same manner as in the above embodiment, and therefore the structure is not limited to one in which the filament 21 and the bimetal switch 23 are housed in the outer tube 1.

Furthermore, in each of the embodiments described above, the proximal conductor 16 is fixed to the tip of the bimetal 17 by welding, but the present invention may be achieved by other means such as caulking or screwing.

According to the invention described in detail above, a long proximal conductor is arranged along the longitudinal direction of the arc tube, and one end of the proximate conductor on the electrode side located on the base side is connected to the same electrode as the electrode facing this electrode. Another thermally responsive metal member is attached to the arc tube support member at a potential via a thermally responsive metal member, the other end is supported by the arc tube support member at the same potential as the one end, and is attached to the arc tube support member. The adjacent conductor is in contact with the arc tube at room temperature, and is moved away from the arc tube by a thermally responsive metal member during lighting. Therefore, since the adjacent conductor is in contact with the arc tube over almost the entire length, the starting voltage is low due to the cooperative action of the starting voltage, which is a sinusoidal voltage with a peak starting voltage superimposed, and the adjacent conductor. It will also be possible to start it with certainty. Moreover, since the adjacent conductor separates from the arc tube bulb after lighting, the light emitted from the arc tube is no longer blocked, blackening is prevented, and thermal deterioration of the adjacent conductor is also eliminated. One end of the proximate conductor is fixed to one thermally responsive metal member, and the other end is pressed by another thermally responsive metal member, so that the proximal conductor reliably contacts the arc tube at room temperature. Moreover, since the posture of the adjacent conductor is established in a constant manner, regulation during assembly becomes easy, and the assembly work becomes simple.

Furthermore, as mentioned above, since reliable starting is possible with a low starting voltage, it is possible to provide a highly efficient lamp using a starting gas such as xenon gas that greatly contributes to improving light efficiency.

[Brief explanation of the drawing]

Figures 1 to 7 show an embodiment of this invention, in which Figure 1 is a front view of the entire high-pressure sodium lamp, Figure 2 is a sectional view taken along the line - in Figure 1, and Figure 3 is a cross-sectional view of the high-pressure sodium lamp. 4 is a sectional view taken along line - in Figure 1, Figure 5 is a top view showing the relationship between the filament and the bimetal switch, Figure 6 is a lighting circuit diagram, and Figure 7 is a sectional view taken along line - in Figure 1. The figure is a characteristic diagram showing the starting voltage, and Figures 8 and 9 show modified examples.
Figure 8 is the front view of the whole, Figure 9 is the middle of Figure 8.
FIG. 10, which is a sectional view taken along the line, 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, 19... Bimetal (thermally responsive metal member), 18a... Through hole, 21... Filament (heating resistor), 23... Bimetal switch (thermally responsive switch).

Claims (1)

[Scope of utility model registration request] 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, is placed inside an outer tube with a cap attached to one end. When installed and started,
In the discharge lamp that is lit by superimposing a peak starting voltage on a sinusoidal voltage between the opposing electrodes, a long proximal conductor is arranged along the longitudinal direction of the arc tube, and the proximal conductor is connected to the cap side of the discharge lamp. One end of the electrode side where it is located,
The adjacent conductor is fixed to an arc tube support member having the same potential as the electrode facing the electrode via a thermally responsive metal member, and the other end of the adjacent conductor is freely supported by the arc tube support member. The vicinity of the other end is pressed by another heat-responsive metal member fixed to the arc tube support member, and at room temperature, the adjacent conductor is in contact with the outer surface of the arc tube, and during lighting, the adjacent conductor emits light. A metal vapor discharge lamp characterized by being separated from the tube.