JPS598951B2 - metal vapor discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal vapor discharge lamp with improved restart characteristics.

In general, high-pressure sodium lamps have higher efficiency than mercury lamps and the like, so they are widely used as various light sources.

However, this high-pressure sodium lamp had a high starting voltage and could not be lit with a mercury lamp ballast, requiring a special ballast.

To improve this, a starting voltage generation circuit consisting of a resistive heating element such as a filament and a normally closed bimetal switch connected in series is connected in parallel with the arc tube, and at the time of starting, current is passed through the resistive heating element through the bimetallic switch. This is configured to generate heat, use that heat to open a bimetal switch, and at that moment apply a high-voltage kick voltage generated by the inductance of the ballast to the arc tube, and connect it to one electrode near the arc tube. The above-mentioned king voltage is applied to a relatively small gap between the adjacent conductor and the other electrode to generate a large potential gradient and an arc discharge in the arc tube, thereby stabilizing the mercury lamp. A device has been developed that can be lit using a device.

By the way, this type of lamp has a problem that sodium ions inside the arc tube are attracted to the nearby conductor and react with the materials that make up the arc tube during lighting, causing blackening of the arc tube.
After lighting, either pull this adjacent conductor away from the arc tube or =
It is necessary to electrically isolate the proximate conductor from the one electrode side, and a proximal conductor cutting bimetal is provided to mechanically separate the proximal conductor from the arc tube or to electrically isolate it from the one electrode side.

However, in conventional lamps, when the lamp is turned off and restarted after it has not completely cooled down, a much higher kick voltage than the designed value is generated, resulting in burnout of the ballast or failure of the socket. Short circuits and dielectric breakdown may occur.

When the cause of this problem was investigated, it was found that the bimetallic switch returns to its original state earlier than the adjacent conductor disconnection bimetal during the cooling process of the lamp after extinguishing the lamp, resulting in such a problem.

In other words, the quigging voltage generated at the moment the bimetal switch is opened can be quite high, but this quigging voltage is applied between the other electrode and the adjacent conductor, causing a discharge between them. As a result, no voltage higher than the discharge starting voltage is generated between the other electrode and the adjacent conductor.

When starting from room temperature, power supply is started with both the adjacent conductor disconnection bimetal and the bimetal switch restored, so the bimetal switch opens first due to the heat of the resistance heating element and discharge occurs. started,
After this, the adjacent conductor is cut off by the heat from the arc tube.
The barrel is deformed and the proximal conductor is separated from the arc tube or electrically disconnected from one electrode side, so this proximal conductor is close to the arc tube or electrically connected to one electrode side. In this state, a quigging voltage higher than the discharge starting voltage between this adjacent conductor and the other electrode is not generated.

However, at the time of restart, the bimetal switch that was in the open state due to the heat from the arc tube returns before the bimetal switch that disconnects the adjacent conductor, and when the electric power is restarted in this state, the resistance heating element generates heat and the adjacent conductor The bimetal switch opens before the separated bimetal is completely restored.

Therefore, in such a case, a high kick voltage corresponding to the discharge starting voltage is generated when the nearby conductor is not completely close to the arc tube or when the nearby conductor is cut off from one electrode, and the ballast However, in the past, little consideration was given to the relationship between the bimetal switch and the bimetal switch's recovery speed, and the lamp was used in an atmosphere similar to bare lighting in cold regions. Since the heat dissipation conditions are not constant from the condition to the case where it is housed in a sealed type floodlight with poor heat dissipation, the above-mentioned problems occur.The present invention was made based on the above circumstances. The purpose of this is to reliably prevent the generation of excessive kick voltage when restarting a device equipped with a starting voltage generating circuit in which a resistive heating element and a bimetal switch are connected in series and a nearby conductor. The purpose is to obtain a metal vapor discharge lamp.

The present invention will be explained below according to an embodiment shown in the drawings.

In this embodiment, the present invention is applied to a 360W high-pressure sodium lamp, and in the figure, 1 is an outer tube, 2 is a stem, and 3 is a cap.

A light emitting tube 4 is housed within the outer tube 1.

The arc tube 4 is made of a translucent alumina ceramic material, and end caps 5 and 6 made of niobium are sealed at both ends, and electrodes 1 are attached to these end caps, respectively.
, 8 are installed.

The arc tube 4 is attached via holders 11 and 12 to supports 9 and 10, which serve both as support and power supply.

Support}9 and 10 are lead-in wires 1 enclosed in the stem 2.
3 and 14, and the tip of one support 9 is held at the head of the outer tube 10 by leaf springs 15, 15.

One electrode 1 of the arc tube 4 is connected to one support 9 via a holder 11, and the other electrode 8 is connected to the other support 10 via a holder 12.

Note that the support 12 is electrically insulated from one of the supports 9 by an insulating tube 16K.

The arc tube 4 contains mercury and sodium 30
It is filled with xenon gas at 0 Torr.

Further, a starting voltage generating circuit 11 is built in the outer tube 1, and this starting voltage generating circuit 17 is constructed by connecting in series a resistance heating element 18 made of a tungsten filament and a normally closed bimetallic switch 19. ing.

This starting voltage generating circuit 17 supports}9.1 0
and is connected in parallel with the arc tube 4.

Further, 20 is a substrate that supports these resistance heating element 18 and bimetal switch 19, and this substrate 20 is formed of an electrically insulating material.

The resistance heating element 18 made of the above-mentioned filament is erected on the substrate 20 in a meandering manner.

Further, the bimetal switch 19 has a bimetal plate 21.
It consists of a movable contact 22 and a fixed contact 23 attached to the tip of this bimetal plate 21, and this bimetal plate 21 is attached on the base 20 in close proximity to the resistance heating element 18, and this resistance heating element 18 It is configured to receive heat from the body 18 and heat from the arc tube 4.

Further, reference numeral 24 denotes a proximity conductor, which is formed from a wire made of a high melting point metal material such as molybdenum or tantalum, and is close to the outer peripheral surface of the arc tube 4 and extends along the longitudinal direction of the arc tube 4. It is provided.

One end of the proximal conductor 24 is bent into a grung shape, and its tip is supported by a shaft supporting member 25 attached to one support 9 so as to be rotatable and slidable in the axial direction.

Further, the other end of this proximity conductor 24 is welded to the tip of a proximity conductor separation bimetal 26 protruding from one support 9, and this proximity conductor 24 is connected to the shaft support member 25 and the proximity conductor separation bimetal 26 to one support 9, that is, one electrode 1 side, and when the adjacent conductor separation bimetal 26 is deformed by the heat from the arc tube 4, it rotates around the shaft supporting member 25 and is connected to the one support 9, that is, one electrode 1 side. configured to be spaced apart.

The bimetal plate 21 of the adjacent conductor disconnection bimetal 26 and the bimetal switch 19 is made of a highly heat-resistant bimetal plate, such as TNY bimetal manufactured by Tokyo Shibaura Electric Co., Ltd. (high expansion coefficient side material: Ni-Mn-F).
e type alloy, low expansion coefficient side material: Ni-Fe type alloy, maximum operating temperature 450℃) or HTY bimetal (
The high expansion coefficient material is a Ni-Cr-Fe alloy, and the low expansion coefficient material is a Cr-Fe alloy (maximum operating temperature: 550°C).

The thickness t1 of the adjacent conductor separation bimetal 26 is thinner than the thickness t2 of the bimetal plate 21 of the van metal switch 19, and the ratio t1/t2 of these thicknesses is t1/t2≦0.8. , and the thicknesses 1, 12 are all 0.0
5mm or more 0. 2 rm or less.

One embodiment of the present invention constructed as described above is lit by a mercury lamp ballast A as shown in FIG.

In a low-temperature state, the proximate conductor disconnection bimetal 26 and the bimetal plate 21 of the bimetal switch 19 are both in the restored state, the proximal conductor 24 is close to the arc tube 4, and the bimetal switch 19 is closed. When power supply is started to start from the state, the resistance heating element 18
Electric current flows through and generates heat, and this heat causes the bimetal plate 2 to
1 is deformed and the bimetal switch 19 is opened.

At this moment, a kick voltage is generated by the inductance of the ballast 8, and this kick voltage is applied between the adjacent conductor 24 and the other electrode 8, causing a discharge in the space between them.

In this case, the proximal conductor 24 is close to the arc tube 4 and the distance from the other electrode 8 is small, so the discharge starting voltage between them is relatively low. For example, the voltage is about 2500V.

The discharge between the adjacent conductor 24 and the other electrode 8 causes ionization of the substance enclosed within the arc tube 4, causing an arc discharge between the electrodes 1.8 and starting lighting.

After lighting, the adjacent conductor separation bathometal 26 is deformed by the heat from the arc tube 4, and the adjacent conductor 24 separates from the arc tube 4.

Further, the bimetal plate 21 of the bimetal switch 19 receives heat from the arc tube 4 and is maintained in a deformed state, so that the open state of the bimetal switch 19 is maintained.

Then, when the lamp is turned off, the entire lamp gradually cools down, and correspondingly, the adjacent conductor disconnection bimetal 26 and the bimetal plate 21 of the bimetal switch 19 gradually return to their original positions.

However, since the thickness t1 of the adjacent conductor-separating bimetal 26 is thinner than the thickness t2 of the bimetal plate 21 of the bimetal switch 19, the heat response to its surface area is smaller than that of the bimetal plate 21. Cooling speed is faster.

Therefore, since the proximal conductor disconnection bimetal 26 reliably returns first, the proximal conductor 24 is always close to the arc tube 4 when the bimetal plate 21 returns and the bimetal switch 19 is closed during the cooling process of the lamp. are doing.

Therefore, the resistive heating element 18 is energized when the proximal conductor 24 is not completely close to the arc tube 4, and the heat generated by the resistive heating element 18 opens the bimetallic switch 19, and a kick voltage is applied to the proximal conductor 24. The excessive kick voltage that would occur in such a case can be reliably prevented from being applied.

Since the order of return of the adjacent conductor disconnection bimetal 26 and the bimetal plate 21 of the bimetal switch 19 is determined by making their thicknesses different, the order of return is reliably regulated.

That is, in order to regulate the order of these returns, it is sufficient to vary their cooling rates, so it is also possible to vary their cooling rates by, for example, varying their placement locations.

However, when these parts are housed in the outer tube 1, their placement is practically limited to the vicinity of the neck of the outer tube 1 due to the need to not block the light from the arc tube 4 and other conditions. Under these limitations, even if the placement location is slightly different, there will not be a large difference in the cooling rate, and as mentioned above, the usage conditions of the lamp vary widely, so the cooling conditions for the entire lamp will also vary. = not specified, and the order of return cannot be reliably regulated.

However, as mentioned above, if the thicknesses of the adjacent conductor disconnection bimetal 26 and the bimetal plate 21 of the bimetal switch 19 are different, a clear difference will occur in the cooling rate, and even if there is a slight change in the cooling conditions, the return order cannot be changed. It is something that can definitely be regulated.

In order to confirm such an effect, the adjacent conductor disconnection bimetal 26 of the lamp of the above embodiment and the bimetal switch 1 were tested.
A large number of prototypes were made with various thicknesses 1, 12 of the bimetal plates 21 of 9, and these lamps were turned on for a certain period of time and then turned off, and during the cooling process, the power supply was restarted and restarted.
The kick voltage at restart was investigated.

Table 1 shows an example of the experimental results, and this example was obtained when the lamp was lit bare at room temperature.

As is clear from this result, the adjacent conductor disconnected bimetal 2
If the thickness t of the bimetal switch 19 is made thinner than the thickness t2 of the bimetal plate 21 of the bimetal switch 19, when the bimetal switch 19 is opened after returning and a Quigging voltage is generated, the adjacent conductor 24 is completely connected to the arc tube 4. Because they are close to each other, the generated KIG voltage is stable at 250 0V, and t1
, when the thickness of t2 is made equal, the Kigg voltage is 30
The voltage rises to 00V, and this 3000V is the limit of voltage resistance of stabilizers and the like.

And when t1 becomes thicker than t2, the kick voltage becomes 300
The voltage exceeds 0V, which exceeds the withstand voltage limit of ballasts, etc.

Therefore, in order to prevent the KIG voltage from exceeding 3000V, it is necessary to make at least t smaller than t2.

In addition, as a result of experiments with various lighting conditions for such a lamp, it was found that the cooling rate was the slowest when the lamp was housed in a sealed floodlight. It was found that there was little difference in the return speed of No. 21.

The experimental results in this case are shown in Table 2.

As is clear from this result, the ratio t1 and t2, t,/t2, should be set to 0.000 to keep the kick voltage below 3000V even when the light is turned on in a sealed type floodlight, which has the worst conditions. ．． It is sufficient if it is set to 8 or less.

In addition, as a result of considering the thickness of the adjacent conductor separation bimetal 26 and the bimetal plate 21 of the bimetal switch 19 from other points, it was found that if the thickness of these is less than 0.05 mm, permanent deformation occurs during use. It was found that the bimetal switch 19 could not be put into practical use due to the following problems, and as a result of investigating the relationship between the thickness of the bimetal plate 21 of the bimetal switch 19 and the time it takes for it to recover and restart, the results shown in Figure 4 were obtained. Obtained.

In addition, the solid line in FIG. 4 shows the case of naked lighting, and the broken line shows the case of being housed in a closed type floodlight.

Since the restart time of this type of lamp usually needs to be 10 minutes or less, the thickness t2 of the bimetal plate 21 is at least 0. 2 It is necessary to make it lower.

If all of the above conditions are satisfied, the generation of excessive kick voltage can be reliably prevented under any usage conditions, and the restart time can be made equal to or less than that of conventional products. be.

Note that the present invention is not limited to the above embodiment.

For example, if the outer tube has a special shape or the like, and the adjacent conductor disconnection bimetal and bimetal switch can be freely arranged, their return order may be regulated by changing their arrangement locations.

In addition, the surface of the adjacent conductor separated bimetal is formed to have a rough surface or black color to increase heat dissipation, and the cooling rate is increased.
The return order may be regulated by

Further, these configurations may be used together.

Further, the present invention can be applied to a device in which a proximal conductor is wound around the outer periphery of the arc tube, and the proximate conductor is electrically separated from one electrode side after lighting by a proximal conductor cutting bimetal.

In addition, the thickness of the bimetal plate of the vanmetal switch and the bimetal of the adjacent conductor may not necessarily fall within the above range depending on the case.

Furthermore, the present invention is applicable not only to high-pressure sodium lamps but also to other metal vapor discharge lamps such as metal halide lamps.

As described above, the present invention differs in their return speed so that the adjacent conductor cutoff bimetal returns before the bimetal switch of the starting voltage generating circuit.

Therefore, when restarting, the bimetallic switch returns before the adjacent conductor is disconnected, and the king voltage is applied while the adjacent conductor is not completely close to the arc tube or is electrically disconnected from the other electrode. This has great effects, such as being able to reliably prevent the occurrence of excessive kick voltage that would destroy the ballast, etc.

[Brief explanation of the drawing]

One side shows an embodiment of the present invention, FIG. 1 is a longitudinal sectional view, FIG. 2 is a view taken along the line II-II in FIG. 1, FIG. 3 is a circuit diagram, and FIG. 4 is a bimetal plate and restart. It is a diagram showing the relationship with time. 1... Outer tube, 4... Arc tube, 1, 8... Electrode, 1
7... Starting voltage generation circuit, 18... Resistance heating element, 1
9... Bimetal switch, 21... Bimetal plate, 24... Proximity conductor, 26... Proximity conductor disconnection bimetal, A... Ballast.

Claims (1)

[Scope of Claims] 1. A starting voltage generating circuit configured by connecting in series a resistive heating element and a normally closed bimetal switch provided close to each other is connected in parallel with the arc tube and housed in the outer tube. A proximate conductor is provided close to the arc tube and connected to one electrode side of the arc tube, and is deformed by heat from the arc tube after lighting to separate the proximate conductor from the arc tube. Or, in the above-mentioned one provided with a nearby conductor disconnection bimetal that electrically isolates from one electrode side,
Erase. A metal vapor discharge lamp characterized in that the close conductor cut off bimetal and the bimetal switch have different return speeds so that the close conductor cut off bimetal returns faster than the bimetal switch of the starting voltage generation circuit when the lamp is turned on. 2. The above-mentioned claim is characterized in that the thickness of the proximate conductor-severing bimetal is formed to be thinner than the thickness of the bimetal plate of the bimetal switch, so that the return speeds of the proximal conductor-severing bimetal and the bimetal switch are made different. A metal vapor discharge lamp according to scope 1. 3 The ratio of the thickness of the adjacent conductor t1 to the thickness t2 of the bimetal plate of the bimetal switch is t,/t2≦0.8, and 0.05+++s+≦t, <o. 2rrano,o
5 mm (t2≦0.2). The metal vapor discharge lamp according to claim 2.