JPS5820116B2 - Howden - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a dimmer 2 that controls the phase of a discharge lamp 1 to dim it, and a switch 3 arranged in the dimmer 2 connects a high impedance lamp in series to the discharge lamp 1. It relates to a discharge lamp dimming device characterized in that the element 4 is selectively inserted, and its purpose is to provide a discharge lamp capable of obtaining smooth and stable dimming conditions up to weak light conditions. Provides dimmer equipment.

FIG. 3 shows a conventional example of a phase-controlled dimmer circuit using thyrisk, in which a leakage transformer 8, a leakage transformer 8, A phase advance capacitor 9, a preheating transformer 10, and a discharge lamp 1 are connected as shown in the figure.

Note that the cyrisk control circuit within the dimmer 2 is omitted here.

In the dimmer circuit, the firing angle of the thyristor 6 is controlled to cut part of the input voltage of the leaky transformer 8, thereby limiting the current flowing through the discharge lamp 1 and reducing its light output. can be narrowed down.

Therefore, this phase-controlled dimming method is ultimately a voltage-controlled method, but here, in order to maintain the lighting of the discharge lamp 1, it is necessary to apply a voltage higher than the discharge maintenance voltage via a stabilizing element. , control the firing angle of the leakage transformer 8
When the output voltage approaches the discharge sustaining voltage of the discharge lamp 1, the lighting becomes unstable, flickering occurs, and eventually disappears, making it difficult to control under weak light conditions.

In addition, in order to compensate for such drawbacks, when the thyristor conducts, its switching operation is used to generate high-voltage, high-frequency pulses in the secondary winding of the leaky transformer 8, and the pulses are applied to the discharge lamp 1. A method that ensures restriking in each half cycle of the pulse and controls even the weak light state is widely used and has achieved some degree of effectiveness, but the noise and noise associated with pulse generation are widely used. There was a problem of an increase in the amount of water, and improvements were desired.

The present invention has been provided in view of the above points, and is a dimming method that is extremely superior to the above-mentioned voltage control method by using a so-called impedance control method that limits the lamp current by increasing the ballast impedance of the lighting circuit. One embodiment of the present invention will be described in detail below with reference to FIG. 11.

FIG. 1 shows a circuit diagram of an embodiment of the present invention, and a capacitor with a low capacitance and high impedance with respect to the lamp current is connected as a high 2 impedance element 4 in series with the discharge lamp 1 of the conventional circuit shown in FIG. , a switch 3 for selectively inserting this capacitor in series with the discharge lamp 1 is disposed within the dimmer 2.

FIG. 2 shows an example of the dimming characteristics obtained by this configuration.

That is, when the switch 3 is closed, the high impedance element 4
Since it is bypassed by the switch 3, it performs the same operation as the conventional circuit shown in FIG. 3, and can continuously dim the light output from 100% to 1%, as shown by curve 2 in FIG. 2, for example.

Next, when the switch 3 is opened, the discharge lamp 1 is turned on via the capacitor, which is the high impedance element 4, so that the current is drastically reduced, and it is possible to obtain a dimming characteristic as shown in curve 3 in FIG. 3, for example.

In the embodiment shown in FIG. 1, a capacitor is used as the high impedance element 4, but this may also be a resistance or an inductance. Also, two or more switches 3 and two or more high impedance elements 4 are used, and furthermore, even weak light conditions can be controlled. It is also possible to do so.

As described above, the present invention selectively inserts a high impedance element in series with the discharge lamp using a switch placed in the dimmer, so that the light can be dimmed even in weak light conditions with an extremely simple operation. Moreover, stable lighting can be obtained even when lighting with weak light, and it can solve the noise and noise problems of the conventional pulse application method, and if used in parallel with this pulse method, it can further reduce dimming when lighting with weak light. This has the effect of making it possible.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of an embodiment of the present invention, Figure 2 is an explanatory diagram of the same operation as above, and Figure 3 is a circuit diagram of a conventional example, where 1 is a discharge lamp, 2 is a dimmer, and 3 is a switch. , 4 are high impedance elements.

Claims (1)

[Claims] 1. A dimmer is provided which controls the phase of the discharge lamp to dim it, and a switch disposed within the dimmer selectively inserts a high impedance element in series with the discharge lamp. Discharge lamp dimmer device.