JPS641736Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a metal halide lamp.

Metal halide lamps are white light sources with high efficiency and excellent color rendering properties, but their starting voltage is higher than that of high-pressure mercury lamps, so the ballasts for the currently popular and inexpensive high-pressure mercury lamps cannot be used as is. Therefore, efforts are being made to realize its use by creating lighting circuits and the like.

For example, in a metal halide lamp that is equipped with an arc tube in which an auxiliary electrode is provided close to at least one of the main electrodes provided at both ends and is filled with mercury, a halide, and a rare gas, the auxiliary electrode and the A series body consisting of a resistor and a bimetal switch is inserted and connected between the main electrode and the bimetal switch is opened by the heat generated by the resistor. Lamps configured to be lit in a container are known.

However, the lamp with such a configuration has the following problems. In other words, when restarting the lamp, the interior of the arc tube is hot due to residual heat from lighting, and the vapor pressure inside the tube is high, so even if you turn on the power switch again for 10 to 15 minutes after the lamp is turned off, the lamp will not start. Can not. In this case, if you turn on the power switch again after the arc tube has cooled down sufficiently, there will be no such inconvenience, but in practice, it is often necessary to turn on the power switch immediately after turning off the light. It will be done. Incidentally, since an arc tube has a large heat capacity, it takes a long time to cool down, whereas a bimetal switch is small and has a small heat capacity, so it does not take much time to cool down. However, if the bimetallic switch is reclosed before the arc tube has cooled down sufficiently, a preliminary discharge will only occur between the auxiliary electrode, which is shorter in distance than the main electrode, and the main electrode, which is closer to the auxiliary electrode. Therefore, the discharge does not shift to between the main electrodes. As a result, the arc tube continues to be heated even during pre-discharge, which delays the cooling of the arc tube and the drop in vapor pressure inside the tube, resulting in a restart time that is much longer than about 15 minutes, which is a practical problem. It will take 20 to 30 minutes. Further, if the preliminary discharge continues for a long time, the glow discharge with a relatively large current value increases the spatter of the electrode, progresses the blackening, and increases the deterioration of the luminous flux. This problem of luminous flux deterioration due to electrode spatter was noticeable when Penning gas was used as the rare gas.

By the way, a circuit in which a resistor is inserted between the auxiliary electrode and the main electrode that is not adjacent to it is called a starting circuit, but the resistance value of the resistor in the starting circuit is generally not large enough in terms of the starting aid effect. Approximately 10KΩ to 200KΩ
selected from the range. However, recently, the resistance value of the resistor has been lowered, for example, from 1KΩ to 7KΩ, and the predischarge current has been made larger due to the decrease in the resistance value of the resistor. Metal halide lamps have been proposed in which the starting voltage is lowered by scattering a halide layer formed on the electrodes.

However, when the resistance value of the resistor is lowered and the pre-discharge current is increased in this way, the above-mentioned restart time becomes longer and the luminous flux deteriorates significantly.

The present invention was devised in view of these problems, and is an object of the present invention to provide a metal halide lamp that can use a 200V class single choke type ballast for high-pressure mercury lamps, has a short restart time, and has little luminous flux deterioration. It is.

This invention uses neon as the rare gas sealed in the arc tube.
By using Penning gas such as argon and selecting the resistance value of the resistor between 300Ω and 950Ω,
The starting voltage is lowered to a point where a 200V class single-choke type ballast can be used. Furthermore, in order to eliminate the negative effects of longer restart times and deterioration of luminous flux due to lower resistance of the resistor, we use a solid resistance element as the resistor and connect it in series to thermally responsive switches such as bimetal switches. The solid resistance element is arranged close to the thermally responsive switch within a range of 2 mm to 10 mm so that the surface of the thermally responsive plate of the switch and the surface of the solid resistive element face each other, and the solid resistive element is placed close to the thermally responsive switch within a range of 2 mm to 10 mm, and The structure is such that when the switch is closed, the heat of the solid resistance element opens the thermally responsive switch.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows an electrical wiring diagram of a metal halide lamp, which is an embodiment of the present invention, combined with a 200V single-choke type ballast, and shows at least one of the main electrodes 2 and 3 provided at both ends of the arc tube 1. An auxiliary electrode 4 is provided adjacent to the auxiliary electrode 4, and a resistance value of 300Ω is provided between the auxiliary electrode 4 and the main electrode 2 that is not adjacent to the auxiliary electrode 4.
A series body consisting of a resistor consisting of a solid resistance element 5 having a resistance of ~950Ω and a thermally responsive switch consisting of a bimetallic switch 6 is inserted and connected. The arc tube is filled with mercury, halides, and Penning gas mainly composed of neon such as neon-argon or neon-krypton.

so that the surface of the solid resistance element 5 and the surface of the bimetal plate of the bimetal switch 6 face each other,
A solid resistance element 5 and a bimetal switch 6 are disposed close to each other, and the configuration is, for example, as shown in FIG. 2. That is, the solid resistance element 5 is made of a carbon-coated resistor or a resistor made by baking a metal oxide film on a ceramic round bar, and the bimetal switch 6 is made of a bimetal plate 6a and a movable contact rod 6b welded to one end of the bimetal switch 6. and a spring 6c welded to the other end, and an insulator 6e made of glass embedded in both ends to insulate the end of the spring 6c and the end of the fixed contact rod 6d from each other. If the distance between the surface of the solid resistance element 5 and the surface of the thermally responsive plate of the thermally responsive switch consisting of the bimetallic switch 6 or the like is less than 2 mm, a preliminary discharge current will flow and the thermally responsive switch will open instantly, resulting in difficulty in starting. becomes. Moreover, if it exceeds 10 mm, the restart time cannot be sufficiently shortened compared to the conventional method, and the effect of the present invention cannot be obtained. Note that this interval varies somewhat depending on the amount of heat generated by the solid resistance element, that is, the resistance value and wattage.

In Fig. 1, numeral 7 indicates an outer tube, and numeral 8 indicates a 200V single-choke type ballast.

Now, if we apply a power supply voltage of 200V to the lamp,
Current flows through the solid resistance element 5, the bimetal switch 6, the auxiliary electrode 4 and the main electrode 3 through the 200V single-choke type ballast 8, and the main electrode 3 and the auxiliary electrode 4
A preliminary discharge is performed between the arc tube 1 and the gas filled in the arc tube 1 to be excited or ionized, and the lamp is lit. After lighting, the bimetal switch 6 is opened by the heat of the arc tube 1.

Figure 3 shows a halide-containing arc tube manufactured by the usual method, with voltage applied only between the auxiliary electrode and the main electrode adjacent to it, and no voltage applied to the main electrodes that are not adjacent. The preliminary discharge current flowing between the two electrodes was measured by changing the resistance value of the fixed resistance element.

FIG. 4 shows the results of measuring the starting voltage of a metal halide lamp while varying the resistance value of the solid resistance element. The starting voltage of a metal halide lamp is practically 180V when using a 200V class single choke ballast, taking into account the rise in starting voltage during lamp operation and fluctuations in the power supply voltage.
Must be less than or equal to If variations in starting voltage are also considered, the resistance value of the solid resistance element needs to be limited to 950Ω or less.

Figure 5 shows the distance between the surface of the solid resistance element and the surface of the bimetal plate of the bimetal switch (hereinafter abbreviated as the distance between the solid resistance element and the bimetal switch).
This figure shows the results of investigating how the restart time changes with respect to the resistance value of the solid resistance element when the resistance value of the solid resistance element is changed. In the figure, curve 9 shows a structure in which the solid resistance element and bimetallic switch are spaced apart by about 20 mm, and curve 10 shows a structure in which the space is close to about 5 mm. As is clear from this, even if the resistance values of the solid resistance elements are the same, the restart time can be shortened by shortening the distance between the solid resistance element and the bimetal switch, that is, by bringing them closer together. By placing both in close proximity and setting the resistance value of the solid resistance element to 300Ω or more, a restart time of less than 15 minutes can be obtained. In addition, luminous flux deterioration due to glow spatter reduces the resistance value of the solid resistance element to 300Ω.
If a smaller value is selected, the resistance value of the solid resistance element must be set to 300Ω or more, since it increases rapidly due to a large current.

As mentioned above, by configuring the solid resistance element and the bimetal switch to be very close to each other within the range of 2 mm to 10 mm, the restart time is shortened for the following reasons. .
In other words, when restarting a bimetallic switch, the solid resistance element with a larger heat capacity is closer to the bimetallic switch, so the closing time of the bimetallic switch is delayed, and even if the bimetallic switch closes, the standby Even when the discharge starts, the self-heating of the adjacent solid resistance elements opens the bimetallic switch again, preventing the pre-discharge from continuing for a long time, thus reducing the cooling inside the arc tube. Since there is no delay,
This is because the restart time is reduced accordingly.

Note that the heat dissipation of the arc tube during restart after the light is turned off is extremely lower than the heat dissipation due to arc discharge of the arc tube when the light is turned on. That is, the surface temperature of the arc tube during lighting is about 800 to 900°C, while the surface temperature of the arc tube is about 100 to 200°C when restarting after turning off. Therefore, compared to the distance of 2 to 10 mm between the surface of the solid resistance element and the surface of the thermally responsive plate of the thermally responsive switch, it is necessary to keep the distance between the arc tube and the thermally responsive switch sufficiently large, for example, about 20 mm. This makes it possible to ignore the influence of the heat of the arc tube on the thermally responsive switch upon restart. Furthermore, at the time of startup, glow discharge occurs inside the arc tube, and its surface temperature is room temperature.
Since this is extremely low, if the distance between the arc tube and the thermally responsive switch is set as described above, the influence of the heat from the arc tube on the thermally responsive switch can be made negligible.

Next, a concrete example of the present invention will be described.

A 700W metal halide lamp with the structure shown in Figure 1 was manufactured by sealing mercury, neon, and argon Penning gas together with calculated amounts of sodium iodide, indium iodide, and thallium iodide in an arc tube made of quartz glass with an inner diameter of 23.5 mm and a distance between the main electrodes of 57 mm, and sealing an inert gas in the outer tube, and placing a 0.5W carbon film resistor (main heating part) with a resistance value of 750 Ω as a solid resistance element close to the bimetal switch at a distance of 4 mm. When this was lit in combination with a 200V single-chambered ballast and tested, the lamp had a luminous flux of 62,000 lm and an efficiency of 1000 Hz.
88.5lm/W, starting voltage is 160V or less,
Luminous flux maintenance rate after 9000 hours of lighting: 75%, starting voltage
The voltage was 170V, which was a good result.
The restart time was also 9 minutes, and the restart characteristics were also good.
This is shown as curve 11 in the figure. In Fig. 6, curve 12 shows the case where argon gas is used as the rare gas, the distance between the solid resistance element and the bimetal switch of the same structure as above is 16 mm, and the other configurations are the same as those of the above lamp, while curve 13 shows the case where Penning gas of neon and argon is used as the rare gas, the distance is 16 mm, and the other configurations are the same as those of the above lamp. From Fig. 6, when the distance between the bimetal switch and the solid resistance element is 16 mm,
It can be seen that the lumen maintenance factor is lower when a Penning gas of neon and argon is used than when argon gas is used. This is because, when the gap is set to 16 mm and Penning gas is used, the opening action of the bimetal switch due to the red heat of the solid resistance element becomes slow, the preliminary discharge is maintained for a long time, and the glow discharge with a relatively high current value causes more spatter on the electrodes than when argon gas is used, which causes more blackening and greater lumen deterioration.

However, as is clear from FIG. 6, according to the metal halide lamp of the present invention (curve 11), which uses Penning gas of neon and argon and sets the distance between the solid resistance element and the bimetallic switch to 4 mm, the same Penning gas can be used. It can be seen that the luminous flux maintenance factor can be higher than that of the lamp using argon gas and setting the same spacing to 16 mm (curve 13) as well as the lamp using argon gas and setting the same spacing to 16 mm (curve 12). This is because the opening action of the bimetallic switch becomes rapid due to the red heat of the solid resistance element, and the preliminary discharge is not maintained for a long time, so the spatter of the electrode due to the glow discharge becomes smaller.
This is because the progress of blackening is slowed down and the deterioration of luminous flux is reduced.

In addition, it is not limited to 700W metal halide lamps.
Similar good results were obtained regardless of the wattage, such as 250W, 300W, 400W, and 1000W.

As explained above, according to the present invention, a 200V class single choke type ballast for high pressure mercury lamps can be used, and the metal halide lamp has excellent effects such as short restart time and little luminous flux deterioration. You will get a lamp.

[Brief explanation of the drawing]

Fig. 1 is an electrical wiring diagram of a metal halide lamp which is an embodiment of the present invention, Fig. 2 is a plan view showing an example of the mounting structure of a bimetal switch and a solid resistance element, and Fig. 3 is a resistance of the solid resistance element. Figure 4 is a diagram of the relationship between the resistance value of the solid resistance element and the starting voltage, Figure 5 is a diagram of the relationship between the resistance value of the solid resistance element and the restart time, and Figure 6 is a diagram of the relationship between the resistance value of the solid resistance element and the restart time. is a luminous flux maintenance characteristic diagram of a metal halide lamp. 1... Arc tube, 2, 3... Main electrode, 4... Auxiliary electrode, 5... Solid resistance element, 6... Bimetal switch.

Claims (1)

[Scope of utility model registration request] An auxiliary electrode is provided adjacent to at least one of the main electrodes provided at both ends of the light emitting tube, mercury, metal halide and Penning gas are sealed inside the light emitting tube, and a series body of a solid resistance element and a thermally responsive switch which is opened by self-heating of the solid resistance element is inserted and connected between the auxiliary electrode and a main electrode not adjacent to the auxiliary electrode, the resistance value of the solid resistance element is selected to be 300Ω to 950Ω, and the surface of the thermally responsive plate of the thermally responsive switch and the surface of the solid resistance element are arranged to face each other,
The solid resistor element is located 2 mm away from the thermal switch.
and a solid resistance element is disposed adjacent to said lamp within a range of 10 mm from said lamp, and when said thermal switch is closed at the time of restarting said lamp, said solid resistance element is heated to open said thermal switch.