JP2000048979A - Fluorescent tube lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To immediately light a cold-cathode fluorescent tube without changing the control of the voltage fed to it by providing an auxiliary light source means irradiating the fluorescent tube with light energy on a lighting means feeding the voltage for lighting the fluorescent tube sealed with gas. SOLUTION: The AC voltage converted with the DC voltage from a DC/DC converter 10 by a DC/AC inverter 11 is fed to a cold-cathode fluorescent tube 14 storing rare gas and mercury. The voltage Vi detected and converted with the current between electrodes 15 by a tube current detecting circuit section 30 is smaller than the reference voltage determined by the resistors R2, R3 of a lighting switch section 31 immediately before lighting when no current flows after the AC voltage is fed. The light of an auxiliary power supply such as a light emission diode LED emitting light when switching elements Q2, Q1 are turned on is applied to a cold-cathode fluorescent tube 14 to generate an easily ionizable state of gas. A current flows between the electrodes 15 after lighting, the voltage Vi becomes larger than the reference voltage, and the switching elements Q2, Q1 and the light emission diode LED are turned off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent tube lighting device. More specifically, the present invention relates to a fluorescent tube lighting device in which a cold cathode fluorescent tube can be immediately turned on.

[0002]

2. Description of the Related Art In the prior art, in order to light a cold-cathode fluorescent tube in which a gas is sealed, a technique of increasing a voltage between electrodes in order to enhance the startability of lighting is well known.

As a method for increasing the voltage between the electrodes of the cold cathode fluorescent tube, there are a method using an electromagnetic transformer and a method using a piezoelectric transformer.

As shown in FIG. 5, a drive circuit using an electromagnetic transformer converts a DC voltage V from an input voltage Vin.
o to generate a DC-DC converter 10 and a transformer T
AC voltage Ve (approximately 2000 V
rms), a DC-DC converter output switching unit 12 for switching the voltage of the DC voltage Vo, and a tube current detection unit for detecting a current flowing between the electrodes 15 of the cold cathode fluorescent tubes 14. 13 and a cold cathode fluorescent tube 14 in which gas is sealed.

In the driving circuit having such a configuration, first, the input voltage Vin is applied to the DC-DC converter 10.
To generate a DC voltage Vo. This DC voltage Vo is input to the DC / AC inverter 11 and boosted by the transformer T to obtain an AC voltage Ve. This AC voltage V
e is supplied to the electrode 15 of the cold cathode fluorescent tube 14. Here, the tube current detection unit 13 detects a lighting failure or no lighting based on the flow of current between the electrodes 15. Then, in order to obtain a good lighting state, the DC-DC converter output switching unit 12 increases the DC voltage Vo of the DC-DC converter 10. Then, the AC voltage V of the DC / AC inverter 11 supplied to the cold cathode fluorescent lamp 14 is
The voltage of e increases. Thus, the lighting startability of the cold cathode fluorescent tube 14 is increased by increasing the DC voltage Vo.

As shown in FIG. 6, a driving circuit of the type using a piezoelectric transformer is composed of a so-called custom IC and has two rectangular wave signals Va and V at different timings.
b, a driving unit 20, two switching elements Q1 and Q12, a piezoelectric element 21, resonance coils L1 and L2 resonating with the piezoelectric element 21, and a cold cathode fluorescent tube 14 in which gas is sealed. It is configured.

[0007] The driving unit 20 is provided with the electrode 1 of the cold cathode fluorescent tube 14.
A current detector 2 for detecting whether or not a current is flowing between 5
2, a rectifier 23, a protection circuit 24 connected in parallel to the rectifier 23, a comparator 25, and a voltage-controlled oscillator 26.
And a driver 27 for generating two rectangular wave signals.

In the driving circuit having such a configuration, first, when an input voltage Vin is inputted, the rectangular wave signals Va, Vb output from the driving section 20 at different timings alternately turn on / off the switching elements Q11, Q12. By doing so, the coils L1 and L2 and the piezoelectric element 21 resonate, and generate an AC voltage Ve of about 2000 Vmrs according to the boosting ratio of the piezoelectric element 21 with a signal of about 60 to 200 Hz. This AC voltage Ve is applied to the electrode 15 of the cold cathode fluorescent tube 14.
, The lighting operation starts. Here, if the lighting operation of the cold cathode fluorescent tube 14 that has entered the lighting operation is defective or the lighting is not performed, no current flows between the electrodes 15 so that the protection circuit 24 operates to stop the operation of the circuit.

[0009]

However, in the case of a drive circuit using the above-mentioned electromagnetic transformer, the DC voltage Vo of the preceding DC-DC converter is increased in order to improve the lighting startability. Has improved. However, in recent years, the DC-DC converter has been stepped up by a low voltage, or the step-up ratio of the electromagnetic transformer has been increased to increase the output voltage (AC voltage Ve) on the secondary side, thereby improving the lighting startability. There is no other way but to improve the power consumption, and there is a problem that the power efficiency is reduced and the lighting startability is not sufficient even if either of these two methods is adopted.

In a driving circuit using a piezoelectric transformer, a voltage (AC voltage Ve) is output to the secondary side, but an upper limit is set so that a voltage higher than a certain level (eg, a voltage higher than 2000 Vrms) is not output. Stipulates,
If the cold-cathode fluorescent tube does not light for a certain period of time (for example, 5 seconds), the protection circuit operates and the entire circuit is stopped. There is.

Therefore, there is a problem that the voltage supplied to the cold-cathode fluorescent tube must be controlled under the current control, and the method must be solved to realize an immediate lighting.

[0012]

In order to solve the above-mentioned problems, a fluorescent tube light emitting device according to the present invention comprises a fluorescent tube filled with gas, and lighting means for supplying a voltage for lighting the fluorescent tube. The lighting means is provided with an auxiliary light source means for irradiating the fluorescent tube with light energy, and the light energy of the auxiliary light source means is illuminated immediately before the fluorescent tube is turned on. In addition, the auxiliary light source means is formed of a light emitting diode.

As described above, by irradiating the fluorescent tube with the light energy, the gas in the fluorescent tube can be easily ionized when the fluorescent tube is turned on.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, various embodiments of a fluorescent tube lighting device according to the present invention will be described with reference to the drawings. The same components as those in the prior art will be described with the same reference numerals.

As shown in FIG. 1, the fluorescent tube lighting device according to the first embodiment of the present invention is an electromagnetic transformer type lighting means, and has a structure for generating a DC voltage Vo.
-D converter 10 and this DC voltage Vo is converted to an AC voltage V
e, a DC / AC inverter 11, a cold cathode fluorescent tube 14 containing a predetermined gas such as neon, argon, xenon, and mercury (gas), and a cold cathode fluorescent tube 14.
Tube current / detection circuit unit 30 for detecting a current flowing between the electrodes 15 of the LED, and a light emitting diode LE serving as an auxiliary light source means.
It comprises a lighting switch section 31 for emitting D and a light emitting diode LED for irradiating light energy from outside the cold cathode fluorescent tube 14. Among them, the DD converter 10
And the DC / AC inverter 11 have the same configuration as that described with reference to FIG.

The tube current / detection circuit section 30 constitutes a circuit of a resistor R1 and a capacitor C1 connected in parallel to one electrode of the cold cathode fluorescent tube 14 via a diode D1.

The lighting switch section 31 has a predetermined power supply voltage +
A positive input terminal for inputting a reference voltage Vref generated by dividing B by resistors R2 and R3, and a current generated from a current flowing through the cold cathode fluorescent tube 14 detected by the tube current / detection circuit unit 30 A comparator IC1 comprising a negative input terminal for inputting the voltage Vi; a power supply voltage + B connected to the anode side; a cathode side connected to the light emitting diode LED via a resistor R4;
2, a switching element Q1 connected to the cathode side and a switching element Q2 whose output side terminal of the comparator IC1 is connected to the gate and whose anode side is grounded.

In the fluorescent tube lighting device having such a configuration, first, an AC voltage Ve (about 2000 Vrms in the embodiment) necessary for lighting the cold cathode fluorescent tube 14 is used.
Is created by the DC / AC inverter 11. When this AC voltage Ve is supplied to the cold cathode fluorescent tube 14, the current flowing between the electrodes 15 of the cold cathode fluorescent tube 14
0 is detected. Then, when the current detected by the cold cathode fluorescent tube 14 is smaller than the reference voltage Vref determined by the resistors R2 and R3, ie, the voltage Vi obtained by current / voltage conversion by the resistor R1, the diode D1, and the capacitor C1, that is, the cold cathode fluorescent lamp Immediately before the lamp 14 is turned on, when the AC voltage Ve is supplied to the cold cathode fluorescent tube 14 and no current flows through the cold cathode fluorescent tube 14, the switching element Q4
Turns on, the switching element Q3 turns on, the light emitting diode LED emits light, and the light beam (light energy) is applied to the cold cathode fluorescent tube 14.

When the cold cathode fluorescent tube 14 is turned on, a current flows between the electrodes 15 of the cold cathode fluorescent tube 14, the voltage Vi becomes higher than the reference voltage Vref, the switching element Q4 is turned off, and the switching element Q3 is turned off. As a result, the light emitting diode LED is turned off, and irradiation of light energy to the cold cathode fluorescent tube 14 is stopped.

By irradiating the cold cathode fluorescent tube 14 with a light beam (light energy) emitted by the light emitting diode LED immediately before the cold cathode fluorescent tube 14 is turned on, electrons generated between the electrodes 15 are generated. It becomes easy to fly, and as a result, gas molecules are easily ionized, and instant lighting is possible.

The following table 1 proves this point through experiments. Table 1 shows the results of an experiment for evaluating the lighting performance. In the first measurement method at the time of the experiment, the cold cathode fluorescent tube 14 is left in the dark at room temperature for 72 hours or more. Further, lighting is attempted in darkness at room temperature, and the time required for lighting is measured. And a light emitting diode LED to assist lighting
With (green), perform the same experiment 50 times with pear. The color of the light emitted by the light emitting diode LED is preferably green rather than red, and blue is more preferable than green. In the embodiment, green, which is widely used in the market, is used, but is not limited thereto. Of course it is.

In the second measurement method, the sample is left in a dark room at minus 5 ° C. for 72 hours or more. Further, lighting was attempted in darkness of minus 5 ° C, and the time required for lighting was measured. And a light emitting diode LED to assist lighting
With (green), perform the same experiment 50 times with pear.

[0023]

[Table 1]

It can be easily understood that the light is emitted immediately by irradiating the cold-cathode fluorescent tube 14 with a light beam (light energy) emitted from the light emitting diode LED for assisting the lighting. The reason is considered as follows. First, when a predetermined voltage is applied to the cold cathode fluorescent tube 14, electrons jump out of one electrode and are accelerated by a voltage (electric field) applied between the electrode and the opposite electrode. The accelerated electrons collide with the molecules of the enclosed gas and repel the outermost electrons, resulting in a so-called ionized state. This is because the light energy acts to make the electrons easily jump out.

Next, a fluorescent tube lighting device according to a second embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 2, the fluorescent tube lighting device according to the second embodiment is constituted by lighting means of a type using a piezoelectric transformer, and includes a driving circuit (see FIG. 6) described in the prior art. Similarly, a drive unit 20 configured by a custom IC for generating two rectangular wave signals Va and Vb with shifted timings, two switching elements Q3 and Q4, and a resonance coil L1 that resonates with the piezoelectric element 21 , L2, a piezoelectric element 21, a cold cathode fluorescent tube 14 in which gas is sealed,
It comprises a lighting switch section 35 for turning on / off a light emitting diode LED as an auxiliary light source means, and a light emitting diode LED. Since the configuration of the driving unit 20 is the same as that of the related art, the same reference numerals are given.

The lighting switch section 35 is composed of two switching elements Q5 and Q6. The driving section 20 detects whether the cold cathode fluorescent tube 14 is lit or not in the driving section 20.
The light emitting diode LED is turned on / off based on the signals Va and Vb.

In the device having such a configuration, when the input voltage Vin is first input, the rectangular wave signals Va and Vb output from the driving section 20 are switched to the switching elements Q3 and Q4.
Are turned on / off alternately, and the coils L1, L2 and the piezoelectric element 2
An AC voltage Ve (approximately 2000 Vrms) is generated by the resonance of 1.

In the drive section 20, the current flowing in the cold cathode fluorescent tube 14 is detected and a control is performed so that the current becomes constant. Is output. Using this signal, the switching elements Q6, Q
The light-emitting diode LED is caused to emit light by using 5 and the light beam is applied to the cold cathode fluorescent tube 14. Also, the cold cathode fluorescent tube 14
Is turned on, the output of the current detection unit 22 becomes a "HIGH" signal, the switching elements Q6 and Q5 are turned off, and the light emitting diode LED stops emitting light.

Thus, the electrode 1 of the cold cathode fluorescent tube 14
Light is emitted to the cold-cathode fluorescent tube 14 (light energy) until the lamp is turned on by detecting the current flowing between the five lamps, so that immediate lighting startability can be obtained.

Next, a fluorescent tube lighting device according to a third embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 3, the fluorescent tube lighting device according to the third embodiment is constituted by a lighting means of an electromagnetic transformer type (see FIG. 5) described in the prior art, and emits cold cathode fluorescent light when turned on. A light beam (light energy) emitted by the light emitting diode LED is controlled by utilizing a phenomenon that the AC voltage Ve supplied to the tube decreases.

That is, the D / D converter 10 for generating a predetermined DC voltage Vo from the input voltage Vin, and the DC voltage Vo
, A DC / AC inverter 11 for generating an AC voltage Ve to be supplied to the cold cathode fluorescent tube 14, a cold cathode fluorescent tube 14 in which gas is sealed, and an AC / DC converter 37 for converting the AC voltage Ve to a DC voltage. And a lighting switch section 38 as auxiliary light source means, and a light emitting diode LED.

The lighting switch unit 38 receives a reference voltage Vref created by dividing the power supply voltage + B and a voltage Vi obtained by converting an AC voltage Ve into a DC voltage, and compares the input voltage and the two switching elements Q7. , Q8, and when the AC voltage Ve supplied to the cold cathode fluorescent lamp 14 is 1000 to 2000 Vrms, the switching elements Q7 and Q8 are turned on to turn on the light emitting diode LED, and the AC voltage Ve is 200 to 2,000. At 500 Vrms, the switching elements Q7 and Q8 are turned off to turn off the light emitting diode LED.

In the device having such a configuration, the non-lighting AC voltage Ve (1) supplied to the cold cathode fluorescent tube 14 is used.
When 000 to 2000 Vrms is detected, the light emitting diode LED is turned on to emit a light beam (light energy) to the cold cathode fluorescent tube 14. Then, the cold cathode fluorescent tube 14
Is turned on and the AC voltage Ve (200 to 500 Vr
ms), the light emitting diode LED is turned off. In this way, it is possible to control the light beam applied to the cold cathode fluorescent tube 14 based on the change in the AC voltage supplied to the cold cathode fluorescent tube 14.

Next, a fluorescent tube lighting device according to a fourth embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 4, the fluorescent tube lighting device according to the fourth embodiment is constituted by the electromagnetic transformer type lighting means shown in FIG.
A voltage drop of a resistor generated when a predetermined current flows between the electrodes 15 is detected to turn on / off the light emitting diode LED.

That is, the resistor section 40 is interposed between the input voltage Vin and the D-D converter 10, a voltage detection circuit section 41 for detecting a voltage drop of the resistor section 40, and a DC section for generating an AC voltage Ve. / AC inverter 11, cold-cathode fluorescent tube 14, lighting switch section 42 as auxiliary light source means
Are provided.

The lighting switch unit 42 is provided with a comparator IC3 for inputting a reference voltage Vref created by dividing the power supply voltage + B and a voltage Vi obtained by converting a voltage drop of the resistor unit 40 into a DC voltage, and comparing the two with two. Switching element Q
When the AC voltage Ve supplied to the cold cathode fluorescent lamp 14 is 1000 to 2000 Vrms, the switching elements Q7 and Q8 are turned on to turn on the light emitting diode LED, and the AC voltage Ve is set to 200. ~ 500
At the time of Vrms, the switching elements Q7 and Q8 are turned off to turn off the light emitting diode LED.

In the device having such a configuration, no current is flowing immediately before the cold cathode fluorescent tube 14 is turned on, so that no voltage drop occurs in the resistance section 40. Therefore, at this time, the light emitting diode LED is kept on and the cold cathode fluorescent tube 14 is irradiated with light (light energy). Then, when the cold cathode fluorescent tube 14 is turned on, a predetermined current flows between the electrodes 15, and a voltage drop occurs at both ends of the resistance section 40. This voltage drop is detected by the voltage detection circuit unit 41, and the light emitting diode LED is turned off by the lighting switch unit. In this manner, by turning on the light emitting diode LED immediately before the cold cathode fluorescent tube 14 is turned on and irradiating the cold cathode fluorescent tube 14 with a light beam (light energy), the gas in the tube can be easily ionized. It is.

[0041]

As described above, the fluorescent tube lighting device according to the present invention irradiates the fluorescent tube with light (light energy) when the fluorescent tube in which the gas is sealed is turned on. This makes it easy to ionize the molecules of the gas, and there is an effect that instant lighting can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram of a fluorescent tube lighting device according to a first embodiment of the present invention.

FIG. 2 is a schematic circuit diagram of a fluorescent tube lighting device according to the second embodiment.

FIG. 3 is a schematic circuit diagram of a fluorescent tube lighting device according to the third embodiment.

FIG. 4 is a schematic circuit diagram of a fluorescent tube lighting device according to the fourth embodiment.

FIG. 5 is a schematic fluorescent tube driving circuit of an electromagnetic transformer type in the prior art.

FIG. 6 is a schematic diagram of a conventional fluorescent tube driving circuit of a piezoelectric type.

[Explanation of symbols]

10; DD converter; 11; DC / AC inverter; 14; cold cathode fluorescent tube; 15; electrode;
21: Piezoelectric element, 22: Current detector, 23: Rectifier, 2
4; protection circuit; 25; comparator; 26; voltage-controlled oscillator;
27; driver, 30; tube current / detection circuit section, 31; lighting switch section, 35; lighting switch section, 37; AC / D
C conversion section, 38; lighting switch section, 40; resistance section, 4
1: voltage detection circuit section, 42; lighting switch section, LED;
Light emitting diode

Claims (3)

[Claims] 1. A fluorescent tube filled with a gas, and lighting means for supplying a voltage for lighting the fluorescent tube, wherein the lighting means includes an auxiliary light source means for irradiating the fluorescent tube with light energy. A fluorescent tube lighting device, comprising: 2. The light energy of the auxiliary light source means is:
The fluorescent tube lighting device according to claim 1, wherein the fluorescent tube emits light immediately before lighting. 3. The fluorescent tube lighting device according to claim 1, wherein said auxiliary light source means is formed by a light emitting diode.