JPS59138049A - High pressure metal vapor electric-discharge lamp - Google Patents

Abstract

PURPOSE:To stabilize the starting characteristic of a high pressure metal vapor electric-discharge lamp by preventing the operation of a starting circuit until an electric potential is applied to the wall of an emission tube by using the heat- responsive switch of the starting circuit also as a heat-responsive mechanisn for a proximity conductor. CONSTITUTION:A proximity conductor 9 for the assistance of starting is made in contact with the wall of an emission tube 1. At least one end of the proximity condutor 9 is fixed to an emission tube strut through a heat-responsive mechanism. When the breakover voltage of a semiconductor switching element 5 is preset for around 480V, the semiconductor switching element 5 turns on when power source voltage becomes over this level causing the electric charges of a capacitor 7 to be discharged thereby causing an abrupt current to flow in this circuit. As a result relaxation oscillation develops due to the inductance of a stabilizer 12 installed outside the electric discharge tube to produce high voltage pulses. Thus produced voltage is simultaneously applied across the main electrode 2b of the emission tube 1 and the proximity conductor 9 as well as across the main electrodes 2a and 2b thereby starting the electric discharge lamp.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in high-pressure metal vapor discharge lamps such as high-pressure sodium lamps, and more particularly to improvements in high-pressure metal vapor discharge lamps having a built-in starting circuit to facilitate starting.

High-pressure metal vapor discharge lamps such as high-pressure sodium lamps generally have a high starting voltage and are difficult to start using normal commercial power supply voltage. Therefore, in recent years, a method has been frequently adopted in which a high-voltage pulse is generated by a starting circuit built into the lamp and applied to the arc tube along with the power supply voltage to facilitate starting. Demand for such discharge lamps is rapidly increasing because they are extremely convenient because they do not require a separate external starter device.

Currently, the most popular type of discharge lamp with a built-in single circuit as described above has a normally closed type thermally responsive switch 2 and a resistor in parallel with the arc tube 1, as shown in Figure 1. A starting circuit formed by connecting the body 3 in series is connected, and these are connected to the outer sphere 4.
It is constructed so as to be housed in an AC power source 6 via an inductive ballast 5, and is an FV type. In this configuration, when the AC power source 6 is turned on, a current flows through the starting circuit and the thermally responsive switch 2 opens and closes due to the heat generated by the resistor 3, and a high voltage pulse is generated in the ballast 5 due to the interruption of the starting circuit current. Since this high voltage pulse is applied to the arc tube 1 along with the power supply voltage, the discharge lamp starts immediately.

After the discharge lamp starts, the heat response of the arc tube 1 causes the thermal switch 2 to be activated.
is held open, thus stopping the generation of high voltage pulses. However, such a configuration has the following drawbacks. First, since a bimetallic switch is not normally used in the thermally responsive switch 2, some degree of unevenness and variation in opening/closing operation is unavoidable, resulting in unstable starting characteristics. Second, abnormally high voltage (curses) may occur due to unstable starting characteristics, so it is necessary to provide a device to absorb them. Thirdly, since a tungsten filament is usually used as the resistor constituting the starting circuit, there are various drawbacks such as the need for ingenuity when incorporating it into the discharge lamp.

In order to eliminate these drawbacks, attempts have been made to make the oxygen elements in the starting circuit as semiconductors or electronic components as possible, but when trying to incorporate them into discharge lamps, there are problems in terms of heat resistance and size. Satisfies extremely strict conditions in 1. Due to its limited availability, it has not been put into practical use at present.

The present invention has been devised in view of the above-mentioned points, and has advantages such as stable starting characteristics, no need for an abnormal pulse absorber, etc., small size, compact size, and high heat resistance. The present invention aims to provide a high-pressure metal vapor discharge lamp with a built-in circuit.

FIG. 2 shows the basic circuit configuration of a high-pressure metal vapor discharge lamp embodying the present invention. In the figure, reference numeral 1 denotes an arc tube made of translucent ceramic having at least a pair of main electrodes 2a and 2b, and the interior of the arc tube 1 is filled with sodium, mercury, and starting gas.

A thermally responsive switch 3 such as a normally closed bimetal switch is connected in parallel to the arc tube 1, and a semiconductor switching element 5 such as a silicon symmetrical switch (SSS) and a diode 6 are connected in parallel via a resistor 4 if necessary. A starting circuit 8 formed by connecting the circuit and a ferroelectric ceramic capacitor 7 in series is connected. A proximate conductor 9 for starting assistance is brought into contact with the wall of the arc tube 1, and at least one end of the proximal conductor 9 is fixed to the arc tube support via a thermally responsive mechanism. As a result, after the discharge lamp is started, the thermal response mechanism works in response to the heat from the arc tube 1, separating the proximal conductor 9 from the tube wall of the arc tube 1, and sodium ions in the arc tube are transferred to the proximal conductor 9. Prevent it from leaking outside due to being attracted to the water. These are housed inside the outer bulb 10 together with the arc tube 1. The starting circuit 8 has a base 11 which is partially or entirely fixed to one end of the outer bulb 10.
It may be stored in The base 11 is connected to an AC power source 13 via a ballast 12. The semiconductor switching element 5 constituting the starting circuit 8 has a silicon-based PNPN junction, the element part is glass passivated, and the exterior is finished with a glass mold. It has been confirmed that such a silicon junction can withstand temperatures of 400°C to 500°C as long as it is not oxidized, and there is no problem with using it in a discharge lamp.
There isn't. The cut diode 6 having the same finish as the semiconductor device switching element 5 is already commercially available in the type V O' 6 G, so it is sufficient to use that diode.

However, in this case, it should be noted that copper plated with solder is used as the lead wire, but since the solder plating evaporates at high temperatures, it must be removed and removed beforehand.

These semiconductor switching elements 5 and diodes 6 are connected to an outer bulb 10 and/or a base 1 fixed to the outer bulb 10.
However, the inside of the outer bulb 10 is normally kept in a vacuum, so if it is housed inside the outer bulb 10, even if the glass passivation of the semiconductor element leaks during operation, the silicon part will not be damaged. It has the advantage of not being oxidized. The excellent ferroelectric ceramic capacitor 7 is made of barium titanate (
Strontium titanate (SrTi03) is used as a shifter to shift the second transformation point and Gyuri point at the ambient temperature of -30°C to +60°C at which discharge lamps are normally started, and to improve piezoelectricity.
O8) and/or barium zirconate (BaZ
rOs) etc. is added in a proportion of 5 to 15 molar. In order to increase the sintered density, piezoelectricity and pressure resistance of the substrate, 0.2% by weight of manganese dioxide (M n O□) is added.
(7) Using the mixture as a base material, it was formed into a thin plate using a general powder press molding method, and then heated in air for 1300 min.
Baking is performed at a maximum temperature of 1400°C to 1400°C for about 2 hours. Next, a silver film electrode is baked on the fired thin plate at 700°C to 800°C, and a lead wire is attached to this using silver solder or the like. Finally, the whole is overcoated with low melting point glass. Since the inside of the outer sphere 10 is a vacuum, this overcoat prevents the oxygen in the barium titanate from dissociating at operating temperatures and converting the barium titanate into a semiconductor, which deteriorates the withstand voltage characteristics. Helps prevent sublimation of membrane electrodes. In addition,
As long as only the heat resistance of the thermally responsive switch 3 and the resistor 41d is taken into account, ordinary ones can be used.

Next, the operation of the discharge lamp will be explained. First, the commercial AC power supply 13 is 200V to 240V.

50 Hz/60 t (z applied via ballast 12.

This voltage is applied to a parallel circuit of a semiconductor switching element 5 and a diode 6 via a thermally responsive switch 3 and a resistor 4, which also serves as a driving piece for a nearby conductor 9, which is in an on state at room temperature. This voltage charges the ferroelectric ceramic capacitor 7 during one cycle of the AC power supply voltage.

In the next reverse cycle, the charge in the capacitor 7 is superimposed on the power supply voltage, so that a voltage as shown in FIG. 3 is generated in the semiconductor switching element 5 between both ends a and b of the parallel circuit of the dimate 6. do. When the power supply voltage Em is 200V, the peak value of this voltage is 564V, which is 2d times the power supply voltage, based on point a. Therefore, the breakover voltage of the semiconductor switching element 5 is set to 480 in advance.
If the voltage is set to 4, the semiconductor switching element 5 will be turned on when the power supply voltage reaches the value 10, and the capacitor 7' will be blown out. As a sudden current flows through the circuit, relaxation oscillation occurs due to the inductance of the ballast outside the market light, and a high voltage pulse as shown in Figure 4 is generated.

This voltage is simultaneously applied between the main electrode 2b of the arc tube 1 and the adjacent conductor 9, and to both the main electrodes 2a and 2b To'J,
This starts the discharge lamp. In this case, if the value of the resistor 4 is set to such a value that the semiconductor switching element 5 turns on once every few cycles, the time constant will be higher than when generating a pulse once every cycle. A voltage pulse is obtained. From this point, the resistance value 1 of the resistor 4 is
-t5 to 60 (KΩ) is appropriate.

Thus, when the discharge lamp starts, heat radiation from the arc tube 1 increases, so the thermally responsive switch 3 turns off, disconnecting the starting circuit 8 from the power source 13.

Oh, the nearby conductor 9 is 'National Techn.
ical Report.

Vol, 27. No. 3, June 1981”
As described in "Relationship between xenon sealing pressure and discharge starting voltage", this has the effect of lowering the starting voltage of the arc tube 1 to about 100 OV compared to one without a nearby conductor.

Therefore, by providing this, it is possible to provide a margin for the pulse generation voltage in the starting circuit 8, and it is also possible to provide a margin for the withstand voltage of the ballast 12, which is extremely useful.

However, if a potential is applied to the adjacent conductor 9 even after the arc tube 1 is lit, the sodium ions in the arc tube will be attracted to the potential and leak out of the arc tube, so it is necessary to keep it away from the source. Further, the semiconductor switching element 5 and diode 6 that constitute the starting circuit 8 must also be separated from the power supply in a high temperature atmosphere. Therefore, in the present invention, the thermally responsive mechanism of the proximity conductor 9 and the thermally responsive switch 3 of the starting circuit are provided.
It is configured so that it can be used for both. Such a configuration has the following advantages.

■ In the case where the thermal response mechanism of the adjacent conductor 9 and the thermal response switch of the starting circuit 8 are provided separately, when restarting the rung, that is, when the lamp that was lit is turned off and then turned on immediately, the adjacent conductor 9 The thermally responsive switch 3 may close before the light returns to the wall of the arc tube 1. The starting circuit 8 then operates and generates a high voltage pulse, but the lamp may not start because of the high vapor pressure within the arc tube. If high voltage pulses continue to occur under these conditions, various phenomena may occur, such as deterioration of the ballast's withstand voltage performance, radio interference due to high frequency noise, or early deterioration due to vibration of the ferroelectric ceramic capacitor in the starting circuit. Take a break〈.

However, if both are used together as in the present invention, the power is applied to the starting circuit 8 after the proximal conductor 9 comes into contact with the wall of the arc tube with a complete V voltage, so the above-mentioned drawbacks can be eliminated. can.

(2) Since there is only one thermally responsive mechanism, assembly and adjustment are easy, operational reliability is improved, and production costs are reduced.

In FIG. 5, a resistor 4 is connected in series with a diode 6, and these are connected in parallel with a semiconductor switching element 5.
Another embodiment of the present invention is shown in FIG. be.

As shown in Fig. 7, two bimetal pieces are welded to the arc tube support column at two places, one at the base and the other at the bottom of the arc tube 1, and a high melting point metal wire such as molybdenum or tantalum is wired between the two bimetal pieces. This is used as the proximity conductor 9, and the lower bimetal piece constitutes the thermally responsive switch 3. Identical parts are designated by the same numbers in both figures.

Further, FIG. 6 shows an embodiment in which the proximal conductor 9 is wound around the wall of the arc tube, and FIG. 1-1 shows a specific arc tube mounting structure thereof. In these figures, the same parts are designated by the same numbers.

Finally, a specific design example of the present invention will be explained.

The circuit configuration shown in Figure 2 has a rated power of 360W.
This is an example carried out in a high-pressure sodium lamp. The interior of the arc tube 1 was filled with xenon gas along with IJ and mercury.

In addition, the semiconductor switching element 5 has a silicon symmetrical swing f (SSS) with an IdPNPN junction glass passivated and an exterior mokara molded.
) It was used. This breakover voltage is 480V
, the operating current is IA in effective value. Further, as the diode 6, a silicon PN junction with glass passivation and an exterior molded with glass was used. The reverse withstand voltage is 600V, and the forward current is 1. It is IA.

As the resistor 4, a 30Ω carbon film resistor was used.

Further, as the ferroelectric ceramic capacitor 7, Ibara's was used. That is, barium titanate (BaTiOs
), strontium A titanate (SrTiOs), and barium zirconate (B a Z r Os )
(') Mixture of each powder 0 diameter 36 mm + thickness 0.5
It was press-molded into a disk shape of 1,400 mn and baked at 1400° C. for 2 hours. After firing, the diameter will be between Fi31, and this will have a diameter of 3.
A 0 mx silver film electrode was baked at 750° C., and a lead wire was brazed to the electrode. Then, the whole was overcoated with glass powder having a thermal expansion coefficient of 90 x 10-'/°C and fired. The capacitance of the capacitor used is 0
．． 05 μF. The circuit components as described above are
As shown in the figure, the wire connection 1 is housed inside an outer sphere of 1°, and the inside of the outer sphere is kept under high vacuum. When such a discharge lamp was turned on using a high power factor type ballast equipped with a 400W choke coil and a capacitor for improving the power factor, it started immediately at a power supply voltage of 180V, and the thermal switch was activated within 3 minutes after starting. In operation 12, the starting circuit was disconnected and the lamp returned to the normal lighting state. The restart time was about 12 minutes, and the restart was instantaneous without any unnecessary high-pressure pulses. As a life test, a discharge lamp was attached to the floodlight, and after 10,000 hours of 11 hours on and 1 hour off, no abnormalities were found.
l-j was not recognized.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of a conventional high pressure metal vapor discharge lamp, Figure 2, Figures 5 and 6 are circuit diagrams of a high pressure metal vapor discharge lamp according to the present invention, and Figures 3 and 4 are the same. Voltage waveform diagrams of part of the discharge lamp circuit, FIGS. 7 and 8, are actual assembly diagrams. In FIG. 2, FIG. 5 to FIG. 8, 1... arc tube;
2g/2b...Main electrode, 3...Thermal response switch, 4...
・Resistor, 5... Semiconductor switching element, 6...
Diode, 7... Ferroelectric ceramic capacitor, 8... Starting circuit, 9... Proximity conductor, 10... Outer bulb, 11... Cap, 12... Ballast, 13... Alternating current power supply. Figure 1 Figure 2 10 Figure 3 Figure 4

Claims (1)

[Claims] 1. An arc tube (1) having at least one pair of main electrodes (2a) and (2b), and a starting aid for applying a potential to the tube wall of the arc tube (11) via a thermal response mechanism. adjacent conductor (9
), semiconductor switching element (5) and diode (6
), a ferroelectric ceramic capacitor (7) and a thermally responsive switch (3) are connected in series to the parallel circuit, and these are connected in parallel to the arc tube t11. Thermal response switch (3) of the starting circuit (8)
is also used as a thermal response mechanism for the adjacent conductor (9), so that the starting circuit (18) does not operate until a potential is applied to the wall of the arc tube (1). A high-pressure metal vapor discharge lamp featuring: 2. The starting aid proximity conductor (9) is configured to contact and separate from the wall of the arc tube (1) by a thermally responsive mechanism. High pressure metal vapor discharge lamp. 3. The starting assisting proximity conductor (9) is configured to be electrically isolated from at least one electrode of the arc tube (1) by a thermal response mechanism. The high-pressure metal vapor discharge lamp according to item 1. 4. The arc tube (1) is made of translucent ceramic, and the interior of the arc tube (1) is filled with a luminescent metal such as an alkali metal, a starting gas, and a buffer gas source. A high-pressure metal vapor discharge lamp according to claim 1. 5. A resistor (4) of 5 [KΩ] to 60 [KO3] is connected in series with the diode f61 of the parallel circuit of the semiconductor switching element (5) and the diode (6) constituting the starting circuit (8). A high-pressure metal vapor discharge lamp according to claim 1, characterized in that: