JPH0341957B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a variable color lighting device that can change the color of emitted light.

[Background technology]

Variable color lighting devices are used, for example, as display devices in stadiums and halls, and lighting devices in stores and discotheques.
By individually controlling the phase of a plurality of lighting loads that emit light of different colors, such as green and blue, various colors can be obtained by changing the luminous flux ratio of each emitted color.

That is, as shown in FIGS. 5 and 6, for example, current limiting elements 5 to 7 and discharge lamps 8 to 10 each emitting light of a different color are connected to both ends of an AC power source 1 via phase control thyristors 2 to 4, respectively. At the same time, a capacitor 1 is connected between the control terminals of each thyristor 2 to 4.
By connecting a series circuit of 4 to 16 and variable resistors 17 to 19 and relaxation oscillation circuits 23 to 25 consisting of voltage response elements (SBS) 20 to 22, and appropriately changing the resistance values of variable resistors 17 to 19, desired results can be obtained. I was trying to get some light. In addition, discharge lamps 8 to 10
is entirely covered with a diffusive globe 26 to improve the mutual mixing of the three colors.

However, in this conventional device, the degree of color mixing is set by controlling the phase of the lighting loads 11 to 13 that emit light of different colors, so that all of the lighting loads 11 to 13 emit light during a half cycle of the AC power source 1. There will be a period during which
Lighting loads 11 to 13 from AC power supply 1 during this period
The disadvantage is that the power supply to the device becomes extremely large, the utilization rate of the power supply becomes low, the crest factor of the input current becomes large, and the flickering becomes large.

[Purpose of the invention]

The present invention has been made in view of these drawbacks, and provides a variable color lighting device with high power utilization.

[Disclosure of the invention]

The present invention selectively and rapidly switches switch elements connected in series to each of the lighting loads emitting light of different colors, and by making the on-period of the switch elements variable, one lighting load can be instantaneously switched. The above object has been achieved by making it possible to visually obtain an arbitrary luminescent color while only emitting light.The present invention will be explained below based on the embodiments shown in the drawings.

Figure 1 shows an embodiment of the present invention, in which a variable resistor serving as a current-limiting impedance is installed at both ends of a DC power supply DC.
A discharge lamp load L is connected via VR and a changeover switch SW. As the discharge lamp load L, for example, a double tube structure as shown in Japanese Patent Application No. 58-131593, which is the original application, is used. That is, three inner tubes LR, LG, and LB are coated with phosphors that emit red, green, and blue light, each forming a discharge lamp with a different emission color, and an outer tube that houses these inner tubes. A discharge lamp load L is formed from the tube TO, and each of the inner tubes LR, LG, and LB is paired with a variable resistor VR serving as a current limiting impedance to form a lighting load. The changeover switch SW has each contact a~
By selectively turning on d, the lighting loads connected to the contacts are made to emit light selectively and sequentially, and the switching cycle is determined by the time delay of the phosphor coated on each arc tube and by the human touch. The length is set so short that the transition of the discharge path cannot be detected due to the afterimage phenomenon of the eye. For example, such a cycle is
10ms or less is sufficient. The variable resistor VR serves as a current limiting impedance for the discharge current and also for adjusting the brightness, and by changing the resistance value, the overall illuminance can be changed.

Figure 2 shows another embodiment in which control variable resistors VR1 to VR3 are added in series with each inner tube, and by adjusting each resistance value in advance, it is possible to obtain appropriate hue and brightness. I can do it.

FIG. 3 shows an example of a time chart for each of the above embodiments. During the period from t0 to t1, one cycle of the power supply is divided into three equal periods in which the red, green, and blue lighting loads each emit light. The light emitting color is white, and after t1, the period during which the blue lighting load emits light is changed to zero, and the period during which the red and green lighting loads emit light is changed to a length that is equal to one cycle of the power supply. This makes the overall luminescent color yellow.

In this way, by rapidly switching the on-period of each lighting load and changing the on-period, it is possible to visually obtain any mixed color, and at the same time, only one lighting load can be instantaneously obtained. Since no light is emitted, the utilization rate of the power supply is significantly improved compared to conventional phase control, which instantaneously causes multiple lighting loads to emit light at the same time.There is also less flickering and input current waveform distortion. Become.

Fig. 4 shows still another embodiment, in which a transistor high-frequency inverter HF is connected to both ends of the commercial power supply AC via a diode bridge D, a smoothing inductance Li, and a capacitor Ci, and the output end of the inverter HF is connected to both ends of the commercial power supply AC. It is connected to each inner tube LR, LG, and LB via a variable inductance VL for current limiting (for brightness adjustment) and a changeover switch SW. In this embodiment, since AC lighting is used, a filament coil coated with an electron radioactive substance is used as the electrode of each inner tube, and an inverter is used.
Preheating is obtained from the secondary side of the HF. The device in this example has a small circuit loss, high-frequency lighting, which has the effect of good luminous efficiency, and uses inductance VL as the current limiting impedance, so the power supply voltage (in this example, the inverter output This has the special effect that the voltage does not have to be increased very much. In other words, when the changeover switch SW is switched at high speed, the current is momentarily cut off each time it is switched, but if inductance is used as the current limiting impedance, L (di/dt) will change in response to this momentary change in current. A corresponding kick voltage is generated in the inductance and is applied to the next-stage inner tube superimposed on the power supply voltage. Therefore, in response to this superimposed high voltage, the next-stage inner tubes will fire smoothly, resulting in stable sequential lighting.

〔Effect of the invention〕

As described above, the present invention connects a switch element to each of the lighting loads that emit light of different colors, switches the switch elements sequentially at high speed, and makes the ON period of each switch element variable, thereby reducing the power utilization rate. It was possible to improve the input current waveform and obtain an arbitrary luminescent color with less flicker.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram showing another embodiment of the invention, Fig. 3 is a time chart of the same, and Fig. 4 is a circuit diagram showing another embodiment of the invention. A circuit diagram showing an example, FIGS. 5 and 6 are circuit diagrams showing a conventional example. SW...changeover switch, L...discharge lamp load,
LR, LG, LB…inner tube (red, green, blue, respectively), VL…
variable inductance.

Claims (1)

[Scope of Claims] 1. A switch element that is selectively turned on is connected to each of three or more lighting loads that emit light of different colors, and each series circuit of the lighting load and the switch element is connected to both ends of a power supply. A variable color lighting device characterized in that the switch elements are repeatedly turned on in sequence at high speed, and the on period of each switch element is made variable. 2. The variable color lighting device according to claim 1, wherein the lighting load is formed by a series circuit of a current limiting impedance including at least an inductance and a discharge lamp.