JPH0354840B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a high pressure metal vapor discharge lamp lighting device with shortened stabilization time.

[Technical background of the invention and its problems]

In recent years, there has been a strong desire to use metal vapor discharge lamps, particularly long-life, high-efficiency high-pressure metal vapor discharge lamps, as light sources for indoor lighting in general homes and the like from the viewpoint of resource and power saving. Currently, incandescent light bulbs and fluorescent lamps are the mainstream light source for indoor lighting, but high-pressure metal vapor discharge lamps have a lifespan approximately 3 to 6 times longer than incandescent light bulbs, and are 5 to 10 times more efficient. In addition, since they are much smaller than fluorescent lamps, their power saving effects are significantly greater if they are used in place of incandescent light bulbs and fluorescent lamps.

However, until now, the main reason why high-pressure metal vapor discharge lamps have been considered unsuitable as light sources for indoor lighting has been their poor luminous flux rise characteristics. That is, when starting the lamp, it takes a certain amount of time for the enclosed luminescent metal to evaporate sufficiently, and therefore, it takes several minutes or more for the luminous flux value to reach its maximum value.

In addition, when restarting the lamp, such as when the power is cut off for some reason and then instantaneously restored, discharge resumes after waiting for the vapor pressure to drop as the lamp cools, and then returns to the specified vapor pressure. Because you have to wait for the luminous flux to reach its maximum value, it takes several minutes or more than 10 minutes for the luminous flux to reach its maximum value.

In ordinary homes, lamps blink very frequently and instantaneous sufficient brightness is required, so the luminous flux rise characteristic described above makes them unsuitable as light sources for indoor lighting.

For this reason, in the past, by using an auxiliary light source together with the arc tube, the auxiliary light source compensated for the lack of luminous flux until the luminous flux of the arc tube reached its maximum value. Metal halide lamps have been developed. However, this lamp uses a light-emitting resistor such as a coil filament as an auxiliary light source, but metal halide lamps have a color temperature of 3200~3200 when the luminous flux reaches its maximum value.
4000K, whereas the color temperature of the coil filament as an auxiliary light source is low at 2850K, so a change in lamp light color occurs between the time the lamp power is turned on and the time the luminous flux reaches its maximum value, making it less visually appealing. There was a drawback that caused discomfort.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a high-pressure metal vapor discharge lamp that can improve the luminous flux rise characteristic, that is, shorten the stabilization time of the lamp, without using an auxiliary light source. With the goal.

[Summary of the invention]

The present invention minimizes the time it takes for discharge to stabilize by supplying microwave power that is higher than the rated power of the lamp at the time of starting a high-pressure metal vapor discharge lamp connected in series to an AC power source via an impedance element. After the lamp is shortened and started, the supply of microwave power is stopped, and the lamp rated power is supplied through the impedance element to maintain lamp lighting.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a circuit diagram of the entire device, and FIG. 2 is a schematic diagram of the switching circuit. In the figure, reference numeral 1 denotes an arc tube, in which electrodes 2, 2 are sealed to a bulb made of quartz glass or the like, and mercury, a luminescent metal, and a starting rare gas are sealed inside. The arc tube 1 is connected in series with a current control hand impedance element 3, and is connected to a power source through power supply terminals 4a and 4b. Note that the current control impedance element 3 can be a single yoke coil or the like. A switching circuit 6 is connected in parallel to the series circuit between the arc tube 1 and the impedance element 3 so that the microwave oscillator 5 can stop the microwave output in a timely manner.
connected via. Microwaves emitted from the microwave oscillator 5 are introduced into a cavity resonator 9 having a window 8 through which the microwaves are blocked but the light is transmitted through a waveguide 7. There is.

According to the high-pressure metal vapor discharge lamp having such a basic configuration, when the lamp is started, microwave power having an energy several times the lamp rated power instantly excites the arc tube 1. The electromagnetic energy generated by this input microwave power instantaneously heats and raises the temperature of the arc tube 1 itself, thereby increasing the vapor pressure of metal halides and the like sealed within the arc tube 1, making it easy to achieve desired results. reveals an emission spectrum.
Thereafter, the switching circuit 6 is opened and the lighting is maintained through the impedance element 3 such as a normal choke. Note that since the microwave power input is several times the lamp rated power, if it is applied for a long time, it may cause softening or rupture of the arc tube bulb, whereas if it is applied for too short a time, the luminous flux will rise instantaneously. I won't be able to do it.

Further, the switching circuit 6 may be controlled by a timer, but a more reliable method is to use a photosensitive body 10 as shown in FIG. The photodetector 10 is installed so as to be able to detect the light emitted from the arc tube 1, and is made of one that can detect a specific wavelength such as ultraviolet light. A specific example is cadmium sulfide (CdS), whose resistance value changes depending on the intensity of ultraviolet rays. In the case of the present invention applied to a 40W metal halide lamp, the resistance value of cadmium sulfide changes by more than 1/10 between before lighting and during stable lighting (when the luminous flux is stable) due to changes in the intensity of ultraviolet rays, and the resistance The switching circuit 6 can capture changes in values with high precision.
Furthermore, in order to sense light other than the ultraviolet region, a filter can be used to set the wavelength of the sensing region. In the case of metal halide lamps, sodium iodide (NaI) has a low vapor pressure, and if a filter is selected to detect the Na line near 590 nm, the color of the lamp light can be changed by the microwave energy input to the lamp. There is no visual difference in the color of the lamp light after it has been turned on by the switching circuit 6 via the normal impedance element 3.

Furthermore, it goes without saying that the photodetector 10 is not limited to cadmium sulfide, and may also be a photodiode, a phototransistor, a photothyristor, or the like.

Next, although the switching circuit 6 can be configured by sequence control such as a relay, a case will be described here in which a semiconductor element which is excellent in weight reduction and miniaturization is used. Reference numeral 11 denotes a rectifier circuit, for example a bridge type full-wave rectifier, which is connected to the microwave oscillator 5. The above rectifier circuit 11
A switching element 12 such as a PNP transistor is connected to the base of the switching element 12, and a waveform shaping circuit 13 is connected to the base of the switching element 12. Although not shown, the waveform rectifier circuit 13 is composed of a Schmitt trigger circuit or the like made up of IC elements such as TTL, and is connected to the photodetector 10.
When a light intensity above a certain level is detected, the base voltage of the switching element 12 is lowered based on the decrease in the resistance value, thereby opening the switching element 12.

Such a switching circuit 6 uses microwave energy to switch on the arc tube 1 after power is applied.
emits light, and when the emission intensity of the predetermined emission spectrum set by the filter increases, the photosensitive body 1
The resistance value of 0 is decreasing. When this resistance value reaches a certain level or less, the waveform rectifier circuit 13 is activated, the switching element 12 is opened, and the power supply to the microwave oscillator 5 is cut off. maintain.

Next, a specific experiment will be explained.

The arc tube 1 uses a metal halide lamp, which is a high-pressure metal vapor discharge lamp. Metal halide lamps are ideal as indoor light sources because they have high efficiency, long life, and superior color rendering properties compared to other high-pressure metal vapor discharge lamps. Since a lamp size of 100W or less is considered appropriate as an indoor light source, here we experimented with a 40W metal halide lamp.

Sodium iodide and scandium iodide are placed in an arc tube 1 with a distance between electrodes of 4 to 5 mm at a weight ratio of 5:1.
About 2 mg of mercury, 4 mg of mercury, and about 100 torr of argon as a starting rare gas were sealed. Such a 40W metal halide lamp has a lamp efficiency of approximately 80lm/W, and when the lamp is stable,
It emits a luminous flux of 3200lm and has a color temperature of approximately 3500K. Cadmium sulfide is used as the photodetector 10.
A filter equipped with a filter that transmits wavelengths of 500 nm or more was used. And the luminous flux emitted from arc tube 1 is
The switching circuit 6 of the photosensitive body 10 was set to be opened when the voltage reached 2600lm, and the microwave oscillator 5 used had an output of 400W.

The luminous flux rise characteristic of a metal halide lamp having such a configuration is shown by a solid line in FIG. Also, the broken line shows the luminous flux rise characteristic when the same lamp is lit using the conventional method without inputting any microwave power.

As is clear from the figure, it takes about 90 seconds for the luminous flux to reach its maximum value in the conventional method, that is, lighting using only a normal ballast, whereas in the method of the present invention, that is, in this embodiment, lighting is performed using microwaves.
400W power is applied for about 5 seconds, and the luminous flux is about
The light rapidly rises to 3000 lm, and then the switching circuit 6 shifts to normal lighting via the impedance element 3. Therefore, the luminous flux reaches its maximum value in about 10 seconds. Color temperature also shows a similar tendency.

By the way, the arc tube is compatible with the rated lamp power,
It is designed to have a tube wall load that optimizes the various lamp light characteristics. Generally, when the load on the tube wall increases, the volume of the arc tube decreases, so the heat capacity of the arc tube itself decreases, and if excessive microwave power is applied to the arc tube, the bulb will soften or burst. Of course, the input power can be determined by the product of the microwave power and the microwave application time, but since the purpose of the present invention is to shorten the stabilization time, it is necessary to shorten the application time and increase the microwave power. There is. used in the above experiment
The arc tube volume of a 40W metal halide lamp is approximately
0.3cc, and when 400W of microwave power was applied to this lamp, it showed a rise characteristic as shown in Figure 3 above, but when microwave power was applied,
When increasing to 600W, it took about 6 seconds, and when increasing to 100W, the luminous flux rose to 3000lm in about 12 seconds. However, when the microwave power was increased to 1kW, the arc tube bulb softened and expanded, and in order to generate 1kW of power, the power transformer for the microwave oscillator also became large, making it difficult to use as a lighting device. This would be extremely large-scale and impractical. Therefore, by selecting an appropriate microwave output, it is possible to obtain a lamp that stabilizes instantaneously within 10 seconds.

In addition, although each of the above explanations has been made with reference to a 40W metal halide lamp, this is intended to improve the luminous flux rise characteristics of the lamp on the premise that it will be used as an indoor light source. However, it can be implemented if the usage conditions require improvement of the luminous flux rise characteristic. Therefore, the present invention is not limited to small metal halide lamps, but can also be applied to medium to large lamps exceeding 100W.

Furthermore, other high-pressure metal vapor discharge lamps such as high-pressure mercury lamps and high-pressure sodium lamps also have the same tendency in luminous flux rise characteristics at startup and restart as metal halide lamps. It is not limited to metal halide lamps.

〔Effect of the invention〕

As detailed above, the present invention is a lighting device that is equipped with a device that supplies microwave power when starting a high-pressure metal vapor discharge lamp, so that the rise time of the luminous flux is extremely shortened when starting or restarting the lamp. Depending on the appropriate microwave output settings, it can be done within 10 seconds, which has the advantage of eliminating the need for an auxiliary light source as in the past. .

[Brief explanation of drawings]

FIG. 1 is an overall circuit configuration diagram of an embodiment of the present invention, FIG. 2 is a schematic diagram of the switching circuit section thereof, and FIG. 3 is a luminous flux rise characteristic diagram. 1... Arc tube, 2, 2... Electrode, 3... Impedance element, 4a, 4b... Power supply terminal,
5... Microwave oscillator, 6... Switching circuit, 7... Waveguide, 9... Cavity resonator, 10...
Photosensor, 11... Rectifier circuit, 12... Switching element, 13... Waveform rectifier circuit.

Claims (1)

[Claims] 1. A high-pressure metal vapor discharge lamp characterized by comprising a high-pressure metal vapor discharge lamp connected in series to an AC power source via an impedance element, and a device for supplying microwave power when starting the high-pressure metal vapor discharge lamp. lighting device.