JP2002164193A - Light adjustment method and device of fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light adjustment method and device of a fluorescent lamp, which is suitable for lighting at low power when the fluorescent lamp is lighted with a lighting illuminance adjusted. SOLUTION: The device comprises a wave forming part 11 which smoothes output from a bidirectional thyristor 7 with a prescribed quantity of a pulsating component left when the desired power obtained by power control of a commercial power source by the bidirectional thyristor 7 is converted to a high-frequency current, and a fluorescent lamp 15 is lighted under illumination control by this high-frequency current, and an inverter 13 which outputs a high-frequency current including a pulse wave periodically projecting from the output of the wave forming part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for dimming a fluorescent lamp, and more particularly to a method and an apparatus for dimming a fluorescent lamp suitable for lighting a fluorescent lamp at low power.

[0002]

2. Description of the Related Art Conventionally, since its control is easy,
Dimming control for incandescent lamps is widely used. Also,
In recent years, dimming control has been performed on fluorescent lamps with low power consumption.

The drive circuit of the bidirectional thyristor will now be described. FIG. 6 (a) shows a resistance variable section 21b which is stepped by a push button switch 21a of an illuminance adjustment section 21.
Is changed by changing the resistance value, the delay amount of the pulse generated by the pulse generation unit 21c in the delay pulse generation unit 23 is determined, thereby driving the bidirectional thyristor 27 by the thyristor drive unit 25. Show. Thereby, the continuously modulating light of the fluorescent lamp is performed.

[0006] Similarly, FIG. 6B shows an illuminance adjustment unit 3.
FIG. 6 is a block diagram of a light control device that performs continuous tunable light using a continuous resistance switching variable resistor such as a volume 1.
FIG. 3C is a block diagram of a light control device that appropriately selects a plurality of resistors having different resistance values by a changeover switch of the illuminance changeover unit 41 and performs stepwise switching.

[0005]

[Technical problems to be solved by the invention]
The fluorescent lamp is a kind of discharge tube, and the bidirectional thyristor is
As shown in FIGS. 2A and 2B, since the phase of the commercial AC power supply is controlled, if the control output is controlled in the dark direction (that is, from FIG. 2A to FIG. 2B), the waveform duty ratio (waveform portion) ), It is difficult to maintain a stable discharge state, and therefore, sufficient dimming in the dark direction cannot be performed, which causes the fluorescent dimming not to spread.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a control output of a bidirectional thyristor when controlling the lighting illuminance of a fluorescent lamp by dimming. By molding, the maximum power consumption 1
An object of the present invention is to provide a method and an apparatus for dimming a fluorescent lamp, which enable a stable light source to be obtained even at the time of low power of about / 10 W.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for dimming a fluorescent lamp which is lit by a high-frequency current. The gist of the present invention is to maintain a lighting state of the fluorescent lamp by including a wave and using the protruding wave as a trigger.

Further, the present invention is characterized in that the projecting wave is a periodic pulse wave obtained by optimizing a smoothing process and a high-frequency generation process after power control and rectification of a commercial power supply. .

The present invention also provides a fluorescent lamp dimming device which converts desired power obtained by controlling the power of a commercial power supply with a bidirectional thyristor into a high-frequency current by an inverter, and turns on the fluorescent lamp by the high-frequency current. A waveform shaping section for smoothing the output from the bidirectional thyristor while leaving a predetermined amount of pulsation components, and an inverter for outputting a high-frequency current including a pulse wave periodically protruding from the output of the waveform shaping section With a pulse wave included in the high-frequency current output from the inverter at the time of lighting at the time of low power as a trigger,
The gist is to maintain the lighting state of the fluorescent lamp.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an embodiment of a fluorescent lamp dimming device to which a fluorescent lamp dimming method according to the present invention is applied. Is shown. First, the configuration of the present embodiment will be described with reference to FIG.

The commercial power is supplied to the pulse generator 1 and a bidirectional thyristor 7 described later. The pulse generator 1 detects a point (cross point) at which the commercial power becomes 0 V from the supplied commercial power, generates a pulse at this cross point, and outputs the pulse to the delay pulse generator 3. The delay pulse generation unit 3 generates a pulse delayed by the delay time set by the delay time adjustment unit 3a and outputs the pulse to the thyristor drive unit 5. The delay time at this time is 周期 cycle (50
Hz power supply is set so as not to exceed 1/100 second). The shorter the delay, the longer the ON time, the brighter the illuminance of the fluorescent lamp, and the darker as the delay approaches the half cycle.

The thyristor drive section 5 applies a gate pulse delayed by a predetermined time from the cross point to the gate of the bidirectional thyristor 7. The bidirectional thyristor 7 is automatically turned off at the cross point when the commercial power becomes 0V. If no gate pulse is applied to the gate of the bidirectional thyristor 7 in this state, the OFF state is maintained and no current flows.

On the other hand, when a gate pulse is applied to the gate of the bidirectional thyristor 7, the bidirectional thyristor 7 is turned on, and the commercial power is supplied to the next cross point. That is, the bidirectional thyristor 7 operates as a switch that is turned on / off in synchronization with the power supply cycle by applying a gate pulse every week at an appropriate time from the cross point. Thus, the phase control output shown in FIGS. 2A and 2B can be obtained from the commercial power supply. FIG. 2 shows the output waveform 1 of the bidirectional thyristor 7 at this time. FIG. 2A is a waveform diagram at the time of maximum light control, and FIG. 2B is a waveform diagram at the time of minimum light control.

The phase control output from the bidirectional thyristor 7 is output to the bridge rectifier 9. Here, the rectification circuit by the diode bridge rectifies the phase control output to obtain the rectified output shown in FIGS. As in FIG. 2, (a) is a waveform diagram at the time of maximum dimming, and (b) is a waveform diagram at the time of minimum dimming.

The rectified output from the bridge rectifier 9 is:
The waveform shaping section 11 performs waveform shaping. That is, the waveform shaping section 11 is an imperfect smoothing circuit as a circuit, and a normal smoothing circuit ideally idealizes a perfect straight line, but this circuit intentionally and positively leaves a pulsating flow. . As a result, a pulsating flow output shown in the waveform diagrams of FIGS. 4A and 4B is obtained. As in FIG. 2, (a) shows the maximum dimming state,
(B) is a waveform diagram at the time of minimum light control.

Next, the pulsating flow output is converted into a high-frequency current having a frequency of about 30 KHz in a high-frequency generator (inverter) 13. Output waveforms of the high-frequency current at this time are shown in FIGS. As in FIG. 2, (a) is a waveform diagram at the time of maximum dimming, and (b) is a waveform diagram at the time of minimum dimming.

In the high frequency generator 13, since the pulsating component is greater than or equal to a predetermined value in the output from the waveform shaping unit 11, ringing is generated corresponding to the pulsating flow, and a pulse wave projecting to a high frequency is generated. The high-frequency current included in the cycle is generated. By applying a high-frequency current including the pulse wave to the fluorescent tube, the pulse wave acts as a trigger for promoting the start of discharge of the fluorescent tube (ignition effect).

That is, since the fluorescent lamp 15 normally has the property that once the discharge is started, the discharge can be maintained even when the voltage is lowered, the discharge is started by utilizing this property and the fluorescent lamp is used. After lighting, lower the voltage to lower the illuminance. This makes it possible to increase the brightness from 10% to 90
% Dimming is possible (it does not reach 100% due to heat loss in the thyristor).

Here, the relationship between the waveform shaping section 11 for outputting a pulsating output including a pulsating component and the high-frequency generating section 13 for generating a pulse wave based on the pulsating component is in a correspondence relationship. In the case where the smoothing is performed more completely, it is necessary to select an inverter that generates ringing with a slight pulsating flow in the high-frequency generator 13 and can include a pulse wave. In the case where the waveform shaping unit 11 for performing the conversion is employed, it is necessary to select an inverter which is less likely to generate ringing resistant to a pulsating flow and can output a short-time pulse wave. Thus, the waveform shaping unit 11 and the high frequency generator 1
By optimizing with 3, the generation of useless pulse waves can be suppressed.

Further, if the pulse wave generated by the high frequency generator 13 and included in the high frequency current is small, it is difficult to turn on the light when the switch is turned on. Conversely, if the pulse wave is large, the light emission becomes unstable. The maximum dimming in this case is a case where a gate pulse is generated with a minimum delay from the 0V cross point. There is also heat loss in the thyristor, and it does not reach 100%. The power (W) and the brightness (LUX) are not directly proportional. Also, the ON time (mSEC) of the thyristor and the brightness (LUX) are not directly proportional. The maximum brightness is specified as 90% and the minimum brightness is specified as 10%.
The brightness becomes 90% when the time is about 70%, and the brightness becomes 10% when the ON time is about 15%. Fluorescent lamp is about 1/1 of maximum
Dimming is possible down to 0 W, and an illuminance of about 1/10 LUX is obtained.

In the above embodiment, the case where the present invention is applied to a fluorescent lamp has been described as an example. However, it goes without saying that the present invention is not limited to this and can be widely applied to, for example, general discharge lamps. .

[0022]

According to the present invention described above, when the fluorescent lamp is lit by controlling the lighting illuminance, the high-frequency current waveform is shaped at least at the time of low-power lighting, thereby providing a periodic light. Since the lighting state of the fluorescent lamp is maintained by including the protruding wave, an excellent effect that a stable light source can be obtained even at the time of low power can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a fluorescent lamp dimming device to which a fluorescent lamp dimming method according to the present invention is applied.

FIG. 2 is a waveform diagram showing an output waveform in a bidirectional thyristor of the fluorescent light dimmer shown in FIG.

FIG. 3 is a waveform diagram showing an output waveform in a bridge rectifier of the fluorescent light dimmer shown in FIG. 1;

FIG. 4 is a waveform chart showing an output waveform in a waveform shaping section of the fluorescent light dimmer shown in FIG. 1;

FIG. 5 is a waveform chart showing an output waveform in an inverter of the fluorescent light dimmer shown in FIG. 1;

FIG. 6 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pulse generating section 3 delayed pulse generating section 3 a delay time adjusting section 5 thyristor drive section 7 bidirectional thyristor 9 bridge rectifying section 11 waveform shaping section 13 high frequency generating section (inverter) 15 fluorescent lamp

Claims (3)

[Claims] 1. A method for dimming a fluorescent lamp that is lit by a high-frequency current, wherein at least at the time of lighting at a low power, a high-frequency current includes a periodic prominent wave, and the prominent wave is used as a trigger to generate a fluorescent light. A method for dimming a fluorescent lamp, characterized by maintaining a lighting state of the lamp. 2. The protruding wave is a periodic pulse wave obtained by optimizing a smoothing process and a high-frequency generation process after power control and rectification of a commercial power supply. Dimming method of fluorescent light. 3. A fluorescent lamp dimming device for converting desired power obtained by controlling the power of a commercial power supply with a bidirectional thyristor into a high-frequency current with an inverter, and lighting the fluorescent lamp with the high-frequency current. A waveform shaping section for smoothing the output from the bidirectional thyristor while leaving a predetermined amount of pulsating components, and an inverter for outputting a high-frequency current including a pulse wave periodically protruding from the output of the waveform shaping section. A lighting device for a fluorescent lamp, characterized in that a lighting state of the fluorescent lamp is maintained by using a pulse wave included in a high-frequency current output from the inverter at the time of lighting at low power as a trigger.