JPH0449236B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for lighting a high-pressure sodium lamp using a ballast having a secondary open circuit effective voltage of 150V or less. Conventional Structures and Their Problems Incandescent light bulbs have been widely used as one of the main lamps for indoor lighting because they have good color rendering properties and can be easily installed and removed in general households. However, in the age of full-fledged energy conservation, the low efficiency of light bulbs has become a problem, and recently there has been a strong demand for the development of compact, high-intensity discharge lamps to replace light bulbs. In particular, small high-intensity discharge lamps that have almost the same luminous color as incandescent light bulbs, which have been widely used by the public, have not yet been commercialized. ~
There is a strong demand for the emergence of high-intensity discharge lamps that have a luminous flux of 60 to 200 W class compared to incandescent bulbs with a lamp power of 100 W. As a lamp that has the potential to meet such demands, the applicant has proposed the JP-A-57-
In Publication No. 9045, Japanese Unexamined Patent Publication No. 57-50763, etc.,
We have proposed a high-pressure sodium lamp that has almost the same light color and color rendering properties as an incandescent lamp, but has lamp efficiency two to three times that of an incandescent lamp. The small, low-wattage lamp we prototyped based on this proposal exhibits a light color similar to that of an incandescent light bulb.
The lamp efficiency of the 50W lamp reached approximately three times that of a light bulb. Moreover, another feature of this lamp is that it can be operated using a small, lightweight ballast from a commercial AC power supply, i.e. 100-120V at 50-60Hz; The distance between the electrodes of the arc tube and the tube voltage at rated lighting are designed to be extremely small compared to conventionally designed high-pressure sodium lamps. For example, in the case of this 50W high-pressure sodium lamp, the total length of the arc tube is 40mm, but the distance between the electrodes is
10mm, the lamp voltage at rated point striking is 40~6V,
The ballast is designed to have a secondary open circuit effective voltage of 90 to 150V. However, in high-pressure sodium lamps of this design, the secondary open circuit effective voltage of the ballast is 90~
The low 150V makes it difficult to start the lamp.
In addition, this results in an extremely long claw discharge time when the lamp is turned on, resulting in a situation where the lamp does not easily transition to arc discharge. When the lamp starts, the electrode material scatters and evaporates rapidly. Therefore, as this starting time becomes longer, the blackening of the arc tube progresses rapidly. Therefore, especially in the case of a small high-pressure sodium lamp having a very small distance between the electrodes as described above, the luminous flux of the lamp rapidly decreases as the lamp is turned on. Purpose of the Invention The present invention has been made in view of the above problems, and provides a lighting method that can reliably start a high-pressure sodium lamp that is lit by a ballast with a secondary open circuit effective voltage of 150V or less. It is something. Structure of the Invention The present invention applies an AC power supply voltage through a ballast with a secondary open circuit voltage of 150 V or less, and further applies a pulse voltage superimposed on this AC power supply voltage to light a high-pressure sodium lamp. The method, wherein the phase angle of the AC power supply voltage is in the range of 40 degrees to 105 degrees or 220 degrees to 285 degrees, and in at least one of the positive and negative half cycles of the AC power supply voltage,
A pulsed voltage is applied to a high-pressure sodium lamp. DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an arc tube used to carry out the method for lighting a high-pressure sodium lamp of the present invention. In the figure, reference numeral 1 is an alumina arc tube with an inner diameter of 5.0 mm at its center, and electrode conductors 2 and 3 made of niobium tubes are directly connected to the inner surfaces of both ends by ceramic cement. It is sealed. Electrodes 4 and 5 are held at the tips of the electrode conductors 2 and 3, and the shortest distance between these electrodes is 10 mm. The arc tube 1 is
The maximum inner diameter is 5.0 mm at the center, but the inner diameter narrows from near the electrodes 4 and 5 to the end of the arc tube 1, and the electrode conductors 2 and 3 are sealed. ing. At the ends, the outer diameter is approximately equal to the outer diameter of the electrode conductors 2 and 3. Inside the arc tube 1, there is a sodium amalgam 6 with a sodium molar ratio of 78% and neon as a starting rare gas.
Approximately 40 Torr of argon mixed gas is sealed. Figure 2 shows the electrical circuit used in the lamp starting experiment. Reference numeral 7 denotes a 50W high-pressure sodium lamp with high color rendering properties, in which an arc tube 1 is incorporated in an outer bulb 8.A sine wave AC power source 10 is connected to this high-pressure sodium lamp 7 via a chiyoke-shaped ballast 9. ing. A high-pressure pulse generator 11 is connected in parallel with the high-pressure sodium lamp 7, and a pulse voltage can be applied between both terminals of the high-pressure sodium lamp 7. After the lamp starts, the pulse voltage is generated as usual. is starting to stop. That is, high pressure sodium lamp 7
As shown in Figure 3, a ballast 9 is connected between both terminals of the
A sine wave AC power supply voltage 12 with a secondary open circuit effective voltage E _O of 100 V and a 60 Hz sine wave is applied through the AC power supply voltage 12, and this is further superimposed to generate a pulse voltage 13 with a half width of ΔW and a peak voltage of V _OP . It is applied to the position of the phase angle θ of the power supply voltage 12 at least every cycle. However, the peak of the sine wave is at 90 degrees. These characteristic values ΔW, V _OP and θ of the pulse voltage 13 can be set to arbitrary values. An experiment was conducted to start the high pressure sodium lamp 7 using the lighting circuit configured as described above. In the experiment, the secondary open circuit effective voltage E _O of the ballast 9 was constant at 100 V, and the high-pressure sodium lamp 7 was supplied with an AC power supply voltage of 12 V.
The aim was to find the necessary conditions for the lamp to start within 10 seconds after the pulse voltage 13 was applied superimposed on the lamp. FIG. 4 shows the relationship between the phase angle θ of the pulse voltage 13 and the AC power supply voltage 12 for starting the lamp when the half width ΔW of the pulse voltage 13 is 15 microseconds. As is clear from the figure, the phase angle θ of the AC power supply voltage 12 is 40 degrees or
It can be seen that if the pulse voltage 13 is applied every cycle in the range of 105 degrees, the high pressure sodium lamp 7 can be easily started at a low voltage with a peak voltage V _OP of about 1 KV. On the other hand, if the phase angle θ is outside this range, lamp starting becomes difficult and the peak voltage V _OP must be increased. In particular, when the value of the phase angle θ becomes large, it suddenly becomes difficult to start the lamp, and when the phase angle θ reaches 110 degrees, in the case of this example, the AC power supply voltage 12 and the pulse voltage 13 are applied. After that, it was recognized that a peak voltage V _OP as high as 4 KV or more was required for arc discharge to start within the arc tube 1 within 10 seconds. The tendency shown in FIG. 4 is not limited to the half-width ΔW of the pulse voltage of 15 microseconds as in this example, but almost changes when it is as narrow as about 1 microsecond or as wide as about 100 microseconds. Nothing happened. Furthermore, the secondary open circuit effective voltage E _O of the ballast 9 is
Almost the same results were obtained even when the voltage was increased to about 150V. It goes without saying that such experimental results do not change even when a pulse voltage is applied to the negative side of the AC power supply voltage 12. That is, the AC power supply voltage 12
If a pulse voltage is applied to the high pressure sodium lamp 7 when the phase angle θ exceeds 285 degrees,
Similarly to the above, starting the lamp becomes very difficult, and after applying the pulse voltage at the same time as AC power supply voltage 12, it is difficult to start the lamp within 10 seconds.
A pulse voltage of 4KV or higher is required. As mentioned above, if the phase of the pulse voltage applied to the lamp with respect to the AC power supply voltage exceeds 105 degrees and reaches, for example, 115 degrees, or exceeds 285 degrees and reaches, for example, 295 degrees, starting becomes suddenly difficult. It was confirmed that this phenomenon is not limited to this example, but is common to all high-pressure sodium lamps that are lit using a ballast with a secondary open circuit effective voltage of 150 V or less. Furthermore, in order to investigate the life characteristics of the high-pressure sodium lamps according to the lighting method of the present invention, the inventors measured the luminous flux maintenance factor (average) and obtained the results shown in the table below. In addition, in order to compare with the lighting method of the present invention, the same table shows the luminous flux maintenance rate ( average) is also shown.

[Table] In the above table, the number of lamps tested for each cumulative lighting time is 5. As is clear from the above table, it can be seen that the lamps lit using the lighting method of the present invention have a significantly improved luminous flux maintenance rate and exhibit excellent life characteristics compared to lamps lit using the lighting method of the comparative example. . This is because, in the case of a lamp lit by the lighting method of the present invention, the starting time, that is, the glow discharge time is short, so that blackening of the arc tube at the time of starting the lamp is suppressed as much as possible. Note that the lighting circuit shown in Figure 3 uses a high-voltage pulse generator installed separately from the ballast.
Of course, a ballast with a built-in high-voltage pulse generator may also be used. In addition, in the above explanation, the case where the pulse voltage is superimposed on the positive half cycle or the negative half cycle of the AC power supply voltage was given as an example, but the pulse voltage is superimposed on the positive half cycle or negative half cycle of the AC power supply voltage. Of course, a pulse voltage may be superimposed every cycle, and this has the effect of making it easier to start the lamp. Effects of the Invention As explained above, the present invention provides a method for lighting a high-pressure sodium lamp that is lit by a ballast whose secondary open circuit effective voltage is 150 V or less, and in which the phase angle of the AC power supply voltage is 40 degrees to 105 degrees. degrees or 220 degrees ~ 285
By applying a superimposed pulsed voltage to a high-pressure sodium lamp during at least one of the positive and negative half-cycles of the AC mains voltage in the range of As a result, the scattering of the electrode material at the time of starting the lamp is significantly suppressed, making it possible to provide a high-pressure sodium lamp lighting method with excellent life characteristics.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an arc tube used to implement the high-pressure sodium lamp lighting method of the present invention, FIG. 2 is a diagram showing an example of a lighting circuit for implementing the high-pressure sodium lamp lighting method of the present invention, and FIG. A waveform diagram of the AC power supply voltage and pulse voltage applied to the high-pressure sodium lamp using the lighting circuit shown in FIG. 2,
FIG. 4 is a diagram showing the relationship between the application position of the pulse voltage and the minimum value of the peak voltage. 1... Arc tube, 2, 3... Electrode conductor, 4, 5...
... Electrode, 6 ... Sodium amalgam, 7 ... High pressure sodium lamp, 8 ... Outer tube, 9 ... Ballast, 10 ... AC power supply, 11 ... High voltage pulse generator, 12 ... AC power supply voltage, 13 ...Pulse voltage.

Claims (1)

[Claims] 1. A high-pressure sodium lamp lighting method that is lit by applying an AC power supply voltage through a ballast with a secondary open circuit effective voltage of 150 V or less, and further applying a pulse voltage superimposed on this AC power supply voltage, The pulsed voltage is applied to the high pressure sodium lamp during at least one of the positive and negative half cycles of the AC power supply voltage when the phase angle of the AC power supply voltage is in the range of 40 degrees to 105 degrees or 220 degrees to 285 degrees. A method for lighting a high-pressure sodium lamp characterized by applying a voltage.