JPH07335387A - Electronic discharge tube lighting device - Google Patents

Abstract

PURPOSE: To pre-heat a filament of a discharge tube by a low voltage and boost it gradually and extend the life of the discharge tube by having a booster circuit part for supplying a motion power source to a self-excited inverter. CONSTITUTION: In a direct current power source part 1, when a switch SO is turned ON, an alternating current AC is supplied to an input side of a bridge diode BD I through a line filter and ES is obtained in an outout side. ES is supplied to a booster circuit part 2 and a voltage is supplied to both ends of the drain and source of EFTQ1 through a reactor TL1. At the same time, the motion standard voltage V1 by resistances R1, R7 is supplied to a third pin of a integrated circuit IC1 and the electric charge of a capaciter C3 is started by a time constant by the resistance R2 and capacitor C3 connected to an eighth pin. In turn, when a signal is inputted to the integrated circuit IC, an inside circuit is operated and a ratio by which FETQ1 is turned ON, OFF is regulated by perceiving the change of the direct current power source ES and the direct current voltage VS is always controlled so as to be a constant voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention In order to light a discharge tube, the present invention changes a conventional power source to a high frequency to light the discharge tube, and disperses filament discharge paths to maximize the use efficiency of the discharge tube. The present invention relates to a lighting device for an electronic discharge tube, which can extend its life and save energy consumption significantly.

[0002]

2. Description of the Related Art A conventional inverter has two switches S.
1, S2 and two power sources E1 and E2 are configured as shown in FIG.
Between the connection point of each switch and the connection point of the power source, an L, C series circuit composed of a retractor L1 and a capacitor C1 is connected. Of the two switches, when S1 is ON and S2 is OFF, L and C
The current iL flowing in the series circuit comes to flow in the direction of the arrow in FIG. When S1 of the two switches is turned off and S2 is turned on, the current iL flowing through the L, C series circuit flows in the direction opposite to that shown by the arrow in FIG.

As described above, the two switches S1 and S2 are alternately turned on and off continuously and repeatedly.
The direction of the current flowing in the C series circuit can be continuously changed, and the speed at which the switch is changed is L, and the speed T = 1 close to the natural resonance frequency (see the following formula 1) of the C series circuit. When / Fo is turned on and off, at this time, the voltages shown in the following equation 2 are generated at both ends of the retractor L1 and the capacitor C1.

[0004]

[Equation 1]

[0005]

[Equation 2]

A circuit of a discharge tube lighting device using a self-excited inverter reconfigured electronically using this principle is a discharge tube lighting device using a self-excited inverter shown in FIG. The circuit of FIG. 1 includes transistors Q1 and Q2 which are semiconductor elements that can be used for the same purpose as the switches in place of the two switches S1 and S2 of the circuit of FIG. 2, and instead of two power sources E1 and E2. An operating power supply E is supplied from the outside, and capacitors C2 and C3 for power storage are connected so that they each have the same role as the power supply E1, and a circuit equivalent to the circuit of FIG. 2 is constructed. In order to alternately turn on and off the two transistors Q1 and Q2, an oscillating transformer T1 is inserted between the connection point of the two transistors Q1 and Q2 and the reactor L1, and the secondary side of the oscillating transformer T1 is inserted. Coil with two transistors Q
A separate operation signal circuit was constructed by connecting the bases and emitters of 1 and Q2 so as to be opposite to each other in the direction of voltage induction.

In FIG. 1, when an operation signal is supplied to the transistor Q2, the transistor Q2 is turned on,
The IL current will flow in the opposite direction of the arrow. At this time, when the voltage induced on the secondary side of the oscillating transformer T1 turns off the transistor Q1 and completely turns on the transistor Q2 so that the oscillating transformer T1 is saturated, The direction of voltage induction in the secondary coil is reversed, and the transistor Q1 is turned on and the transistor Q2 is turned off, so that the IL current flows in the direction of the arrow in FIG. When the oscillating transformer T1 is saturated, the induction direction of the voltage of the coil on the secondary side of the oscillating transformer T1 is inverted, so that the transistor Q1 is turned off and the transistor Q2 is turned on. Subsequent operations are repeated in a self-excited manner even if there is no external signal. At this time, a voltage expressed by the following equation 3 is generated across the capacitor C1.

[0008]

[Equation 3]

In the circuit of FIG. 1, a hot cathode discharge tube is connected to both ends of the capacitor C1, and the voltage generated at both ends of the capacitor C1 is transmitted to the hot cathode discharge tube to light the hot cathode discharge tube. This is a general type of lighting device for a hot cathode type discharge tube using a conventionally used self-excited inverter.

[Problems to be Solved by the Invention] Conventional self-excited inverter
In the hot-cathode type radiation tube lighting device using a cathode, since the total current flowing from the L and C series resonance circuit to the capacitor flows through the filaments on both sides of the hot-cathode discharge tube, the heating voltage Vf of the filament is Resistor R
When f is set, Vf = Rf × iL, and therefore the filament heating voltage Vf varies depending on the current flowing through the capacitors of the L and C resonant circuits, and thus the filament voltage cannot be adjusted appropriately, Thermions are emitted through only one or two points, and high heat is generated at the poles. Therefore, there is a problem that the life of the filament cannot be shortened and the original performance cannot be utilized.

Further, in the prior art, when the supply voltage changes, the output frequency changes, the change width of the high frequency output increases, the voltage across the capacitor C1 of the L and C resonant circuits changes, and the illuminance of the lamp also changes. , It is difficult to supply a preheating voltage to the filament in the initial stage of lighting and to configure a control circuit for taking appropriate measures when the terminal phenomenon of the hot cathode discharge tube is reached. There is a problem in that the efficiency of use of the lighting device becomes poor and the reliability of the lighting device cannot be improved.

The present invention appropriately solves the problems of the prior art and can prolong the life of the hot cathode discharge tube and enhance the reliability of the lighting device. The purpose is to provide a device.

[0012]

According to the present invention, immediately after a DC power source is turned on to a booster circuit section, a self-excited inverter section is supplied with a low initial voltage to such an extent that the hot cathode discharge tube is not lit up so that a filament is formed. Preheat, for a predetermined period,
The voltage gradually rises to turn on the hot cathode discharge tube,
An electronic discharge tube lighting device for supplying a constant voltage to the self-excited inverter unit after a lapse of a predetermined period to substantially shut off the circuit when the end of life phenomenon of the hot cathode discharge tube is reached. . In this electronic discharge tube lighting device of the present invention, an overload protection circuit is incorporated to improve reliability, and
Two or more hot-cathode discharge tubes are arranged in parallel with a structure in which the thermo-electron discharge paths are alternately heated from four locations of the filaments of the hot-cathode discharge tube to improve the usage efficiency of the filament and the voltage of the filament can be easily adjusted. It is characterized in that it can be connected and used, and even if one or more hot cathode type discharge tubes are removed, the remaining hot cathode type discharge tubes are not disturbed to light up. Further, the electronic discharge tube lighting device of the present invention supplies an operating voltage to the self-excited inverter at a low voltage at the initial stage of power-on to preheat the filament of the discharge tube, and then supplies the operating voltage to the self-excited inverter for a predetermined period. Is gradually increased so that the discharge tube is lit at a low voltage, a constant voltage is supplied after the lapse of the predetermined period, and a booster circuit section for stabilizing the operation of the self-excited inverter and an operation at the initial power-on Then, the operation signal is supplied to the self-excited inverter, and after the self-excited inverter has operated for one cycle, the operation signal circuit section for interrupting the supply of the operation signal and the operation voltage supplied from the booster circuit are set to high frequencies. A self-excited inverter part that changes and sends it to the lighting circuit part, and a point that converts the high frequency output from the self-excited inverter to a sine wave and lights the discharge tube Includes a circuit unit, and is characterized in that so as to cause thermionic emission alternately through the discharge path of the filaments is four type state of the discharge tube during lighting of the discharge tube.

Further, according to the present invention, a DC power supply section for outputting a DC power supply obtained by rectifying an AC input voltage, a booster circuit section for converting the DC power supply supplied from the DC power supply section into a predetermined operating voltage, A self-excited inverter unit that converts the operating voltage supplied from the booster circuit unit into a predetermined high frequency, and a lighting circuit unit that converts the high-frequency output from the self-excited inverter into a sine wave to light the discharge tube. Is characterized by. Further, according to the present invention, a DC power supply unit that outputs a DC power supply obtained by rectifying an AC input voltage, a booster circuit unit that converts the DC power supply supplied from the DC power supply unit into a predetermined operating voltage, and the booster circuit. Self-excited inverter part that converts the operating voltage supplied from the unit to a predetermined high frequency, a lighting circuit part that converts the high-frequency output from the self-excited inverter to a sine wave to light the discharge tube, and a lighting circuit part And an overload protection circuit section that stops the operation of the self-excited inverter circuit section when a load occurs. In the present invention,
The booster circuit unit senses a change in the DC power supply that changes in proportion to a change in the AC input voltage, and an operating voltage supplied to a self-excited inverter based on an output from the detector. And adjusting means (control means) for adjusting so that the voltage is always constant. Further, in the present invention, the booster circuit unit is connected to the DC power supply unit, stores a voltage from the DC power supply unit, and a ejector that discharges the accumulated voltage, and is connected to the ejector, and to the ejector. A transistor that controls the accumulation of voltage or the release of voltage from this retractor. Further, in the present invention, the lighting circuit section is characterized in that the filaments of the hot cathode type discharge tube are configured to discharge thermoelectrons alternately through four types of thermoelectron discharge paths. And Further, in the present invention, the lighting circuit unit can be used by connecting two or more of the lighting circuit units in parallel and connecting the hot cathode discharge tubes to the respective lighting circuit units. The lighting circuit section has an infinite impedance when the hot cathode discharge tubes connected to the lighting circuit section are removed.
Since the lighting circuit section from which the hot cathode discharge tubes are removed is virtually the same as being separated from the circuit, any one of the plurality of hot cathode discharge tubes connected in parallel may be used. It is characterized in that even if one or more of the hot cathode discharge tubes are removed, the remaining hot cathode discharge tubes are not disturbed to light up.

[0014]

According to the present invention, in the initial stage of power-on, the booster circuit section that supplies the operating power to the self-excited inverter supplies the operating voltage of the self-excited inverter at a low voltage to preheat the filament of the discharge tube. The operating voltage of the self-excited inverter is gradually increased until the predetermined period elapses, and the discharge tube is lit at a low voltage. After the lapse of a predetermined period of time, a constant constant voltage is supplied to the self-excited inverter to stabilize the operation of the self-excited inverter.

Further, in the present invention, the operation signal circuit section operates at the initial stage of power-on to supply the operation signal to the self-excited inverter, and the operation signal is supplied after the self-excited inverter operates for one cycle. To suspend. The self-excited inverter unit converts the operating voltage supplied from the booster circuit into a high frequency and sends it to the lighting circuit unit. Further, the lighting circuit unit converts the high frequency output of the self-excited inverter into a sine wave to light the discharge tube. At this time, the filaments of the discharge tube alternately generate thermoelectrons through the four types of discharge paths.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 3 is a circuit diagram showing a discharge tube lighting device.
In FIG. 3, AC indicates a regular AC power source, and SO indicates a switch. Further, in FIG. 3, LINE FIL
A block described as TER (line filter) is a power supply noise removing filter, BDI is a rectifying blit diode, and C1 is a waveform shaping capacitor. The DC power supply unit 1 is configured by the above components and the like.

Next, in FIG. 3, the block described as IC1 is an integrated circuit. Further, in FIG.
9, R10, R11 and R12 are sensor resistors for detecting operating voltage, C7 is a capacitor for charging time constant, R8 is a resistor for signal amplification, C4 is a high frequency bypass capacitor,
TL1 is a rejecter, Q1 is a field effect transistor,
R4 is a gate resistor, R6 is a current detection resistor, R5 is a signal chaining resistor, C5 is a high frequency bypass capacitor, R
2 is a resistor for initial power supply, C3 is a smoothing capacitor,
R1 and R7 are resistors for supplying an operation reference voltage, C2 is a high frequency signal bypass capacitor, D1 is a rectifying diode,
R3 is a signal supply resistor, D2 is a high frequency rectifying diode, and C6 is a smoothing capacitor. The booster circuit unit 2 is configured by the above components and the like.

In FIG. 3, Q3 and Q4 are high frequency output transistors, C16 and C17 are power storage capacitors, D7 and D10 are transistor protection diodes, R18 and R19 are base resistors, and D6 and D9 are speed-up diodes. , TL2-F are the primary coils of the transformer for resonance current detection, TL2-S1 and TL2-S.
2 is a transformer side secondary coil for detecting resonance current, TL
Reference numeral 3 is a resonance rekuta. A self-excited inverter unit INV indicated by reference numeral 3 is configured by the above components and the like.

Next, in FIG. 3, C13 and C15 are filament heating voltage adjusting capacitors, C14 is a resonance capacitor, D13, D14, D15 and D16 are filament thermoelectron discharge path dispersion diodes, and LA is a hot cathode type discharge. It is a tube. The above-described components and the like form the lighting circuit section EL indicated by reference numeral 4.

Next, in FIG. 3, Q2 is an operation signal transistor, R14 is a base resistance, and R13 and R17.
Is a resistor for charging time constant, C10 is a capacitor for charging time constant, D4 is a diode for preventing recharge, and D12 is a diode for preventing reverse voltage. By the above-mentioned components and the like, reference numeral 5
An operation signal circuit section TRG shown by is constructed.

In FIG. 3, TR2-S3 is the secondary coil of the transformer TL2-F for detecting the resonance current, D3 and D11 are diodes for high frequency rectification, and SCR.
Reference numeral 1 is a thyristor, R16 is a gate resistance, C9 is a gate capacitor, DIAC1 (DiArc 1) is a diode AC switch, R20 and R15 are voltage detection sensor resistances, C8 is a time constant capacitor, and TL3-S is a second order of the Retractor TL3. The side coil, D21, is a diode for cutting off the operating power supply of IC1. With the above parts,
An overload protection circuit unit PRO shown by reference numeral 6 is configured.

Next, the operation of each circuit section configured as described above will be described separately for each configuration. First, in the DC power supply unit 1, when the switch SO is turned ON, the normal AC power supply AC is supplied to the input side of the blit diode BDI through the line filter, and the DC power supply unit 1 is provided at both ends of the output side of the bridge diode BDI. The output ES is obtained. This DC power supply ES is
It is supplied to the booster circuit unit 2. Then, in the booster circuit section 2, a voltage is supplied to both ends of the drain and the source of the field effect transistor Q1 through the retractor TL1, and at the same time, the operation reference voltage V1 (M1) by the resistors R1 and R7 is the third voltage of the storage circuit IC1. Pin (PIN)
And at the same time, the capacitor C3 starts charging at a time constant of the resistor R2 and the capacitor C3 connected to the 8th pin of the storage circuit IC1. At the same time with these,
By the resistors R10, R11, R12, and C7, the set voltage determined by the following equation 4 passes through R9 and becomes 1 of the integrated circuit IC1.
The pin C is supplied as a set voltage VI signal, but at the initial stage of power-on, the capacitor C7 is charged with the time constant of the capacitor C7 and the resistor R11. Therefore, the set voltage VI is set voltage VI = R12 / ( It gradually decreases from R10 + R12) to R12 / (R10 + R11 + R12). The integrated circuit IC1 is an IC for P, F, C (power, factor, collection), its internal block diagram is shown in FIG. 8, and its characteristic data is shown in Table 1 below.

[0023]

[Equation 4]

[0024]

[Table 1]

Further, in the booster circuit section 2, when the capacitor C3 connected to the 8th pin of the integrated circuit IC1 is charged to the operating voltage VCC of the integrated circuit IC1, the internal circuit of the integrated circuit ICI operates. become,
The pulse output signal is output to pin 7 of the buoyout (VOUT). This pulse output signal is supplied to the gate of the field effect transistor Q1 through the resistor R4. The field effect transistor Q1 turns on when the gate pulse signal is input, and turns off after the energy is accumulated in the retractor TL1. When the field effect transistor Q1 is turned off, the energy stored in the retractor TL1 is rectified through the diode D2 and the capacitor C
After being smoothed by 6, the DC voltage VS is supplied to the self-excited inverter unit 3, energy is accumulated in the retractor TL2, and a voltage is induced across the secondary side coil of the ejector TL2 to be discharged. This induced voltage is the diode D
1 is rectified by the capacitor 1, smoothed by the capacitor C3, supplied to the operating voltage VCC of the storage circuit IC1, and further passed through the resistor 3 to the pin 5 of the integrated circuit IC1 to IDE.
It is supplied as a T signal.

When the field effect transistor Q1 is turned on and a current starts to flow, a voltage is generated across the current sensor resistor R6, and this voltage passes through the resistor R5 to the pin 4 of the integrated circuit IC1 at the VCS pin. It is supplied as a signal.

As described above, when the signal shown in the characteristic data of the integrated circuit IC1 in Table 1 enters each pin of IC1,
The internal circuit of the integrated circuit IC1 operates to operate the DC power source E
When the change in S is sensed, the field effect transistor Q1 turns O
The ratio of N and OFF is adjusted to control the DC voltage VS so that it is always a constant voltage. That is, in the present embodiment, the DC power supply ES is a full-wave rectified AC input voltage, and the DC voltage VS is an operating voltage supplied to the self-excited inverter unit. Of the DC power supply ES which varies in proportion to the variation of the
The N-OFF ratio is adjusted so that the DC voltage VS, which is the operating voltage of the self-excited inverter, is controlled to be a constant constant voltage.

This voltage is varied in inverse proportion to the set voltage VI of the integrated circuit IC1 by the resistors R10, R11 and R12.

At the initial stage of turning on the DC power supply ES, the set voltage VI of the integrated circuit IC1 gradually decreases and the DC voltage VS gradually rises while the time constant of the capacitor C7 and the resistor R11 is charged. , When the charging of the capacitor C7 is completed, the set voltage VI = R12 / (R10 +
A constant constant voltage proportional to the voltage set by R11 + R12) is supplied to the self-excited inverter unit 3 as the DC voltage VS.

Next, the operation signal circuit section T indicated by reference numeral 5
In the RG, at the initial stage when the switch SO is turned on, the DC power source VS is connected to the retractor TL1 and the rectifying diode D.
2 through the resistor R13 for charging time constant,
The capacitor C10 starts to be charged by the time constant of R17 and the charging time constant capacitor C10, and the capacitor C1
After 0 has been charged to the voltage set by the resistors R17 and R13, the integrated circuit IC1 of the booster circuit unit 2 operates and its output signal is supplied to the operation signal transistor Q2 through the base resistor R14. As a result, the operation signal transistor Q2 is turned on, and at the same time, the voltage charged in C10 passes through the collector of the operation signal transistor Q2, the diode D12, and the high frequency output transistor Q4 of the self-excited inverter unit 3. Is supplied to the base of the
Let it be N.

In the self-excited inverter unit 3, when the high-frequency output transistor Q4 is turned on, the DC power supply ES is supplied, and at the same time, the charged power storage capacitors C16 and C17 are charged, and the capacitor is charged by this charging voltage. From C17, through the filament thermoelectron discharge path dispersion diode D16 and the resonance capacitor C14 of the lighting circuit section EL, the filament thermoelectron discharge path dispersion diode D14, and the filament F1 of the hot cathode discharge tube LA, which are indicated by reference numeral 4. Further, a closed circuit that flows to the collector of Q4 is formed through the primary coil TL2-F of the resonance retractor TL3 and the resonance current detection transformer TL2, and the iL1 current flows.

At this time, the resonance current detecting transistor T
Reciprocal voltages are induced in the secondary side coils TL2-S1 and TL2-S2 of L2, turning on the transistor Q4 completely and turning off the transistor Q3.

The transistor Q4 is completely turned on, and i
When the L1 current sufficiently flows and the resonance retractor TL3 becomes saturated, the current of the iL1 gradually decreases.
At this time, 2 of the transformer TL2 for detecting the resonance current is detected.
The voltages induced in the secondary coils TL2-S1 and TL2-S2 are inverted, turning off Q4 in the two high-frequency output transistors Q3 and Q4 and turning on Q3. Then, the voltage charged in the power storage capacitor C16 of the lighting circuit unit 4 passes from the capacitor C16 through the transistor Q3 and further to the primary coil TL2- of the oscillating current detecting transformer.
Current flows in the direction of IL2 through F, the ejector TL3, the thermionic discharge path dispersion diode D13, the capacitor C14, the thermionic discharge path dispersion diode D15, and the filament F2 (see FIG. 4). When the iL2 current sufficiently flows, the resonance retractor TL3 becomes saturated, and the iL2 current gradually decreases. At this time, the transformer TL for detecting the resonance current
The voltage induced in the secondary coils TL2-S1 and TL2-S2 of No. 2 is further inverted, turning on Q4 and turning off Q3 in the two high-frequency output transistors.
The self-excited inverter unit 3 continuously repeats such an operation in a self-excited manner.

When the high frequency output transistor Q4 is turned on, the voltage charged in the capacitor C10 from the operation signal circuit section TRG indicated by reference numeral 5 is discharged through the diode D4. Then, the operating speed of the self-excited inverter becomes relatively much faster than the time constant of being recharged by the resistors R13 and R17 and the capacitor C10, and the discharging time through the transistor Q4 becomes faster than the charging time. Then, the capacitor C10 cannot be recharged, and after the self-excited inverter unit 3 operates for one cycle, the operation signal circuit unit TRG indicated by reference numeral 5 suspends its operation.

Next, the detailed operation of the lighting circuit unit 4 connected to the high frequency output terminal of the self-excited inverter unit will be described with reference to the circuit diagram of the lighting circuit unit of FIG. Figure 4
In the above, when the high frequency output transistor Q3 of the self-excited inverter section is turned off and the high frequency output transistor Q4 is turned on, the voltage of the current iL1 is stored in the power source storage capacitor C17, so that the capacitor C17, the diode D16 and the capacitor C14 are turned on. , The diode D14, the filament F1, the transformer TL3, and the transistor Q4. Then, at both ends of the filament F1, VFAB =
A voltage generated by F1 × iL1 is generated, and the filament F1 is overheated.

At this time, the voltage VF across the filament F2
By CD, from capacitor C17 to filament F2
Through the diode D15 to the capacitor C
14 must carry iL1 current, but no current can flow through diode D15 because diode D15 is connected in the opposite direction to this flow of iL1 current. Therefore, since there is no current flowing through the filament F2, the voltage VF across the filament F2
The CD is virtually zero.

On the other hand, thermionic emission from the filament of the hot cathode discharge tube LA occurs through the discharge path having the highest potential difference. At this time, the voltage applied between the filament poles is given by the following expression 5.

[0038]

[Equation 5]

As a result, VC of the capacitor C14 and i
Since there is a 90 ° phase difference between C, iC × VC
> 0 (iC × VC is greater than zero), the maximum potential is V
It becomes BC and VBD. At this time, the potential difference across VCD is "0", and thermionic emission is from the B pole to the filament F.
2 is diffused toward the whole. Further, iC × VC <0 (i
When C × VC is less than zero), the maximum potential is VAC and V
It becomes AD, and thermionic emission is from the A pole point to the filament F2.
It will spread toward the whole.

Contrary to the above, the output transistor Q3 of the self-excited inverter unit 3 is turned on and Q4 is turned off.
At F, the current of iL2 flows through the transistor Q3 to the diode D13, the capacitor C14, the diode D15, and the filament F2 due to the voltage stored in the power storage capacitor C16. Then, at both ends of the filament F2, VFCD = FCD × i
A voltage due to L2 is generated and the filament F2 is heated. At this time, both ends FAB of the filament F1 must pass the iL2 current from the transformer TL3, the filament F1 and the diode D14 to the capacitor C14, but the diode D14 is connected in the opposite direction to the flow of the iL2 current. IL2
No current can flow through diode D14. Therefore, since there is no current flowing through the filament F1, the voltage VFAB across the filament F1 is effectively zero.

On the other hand, thermionic emission in the filament of the hot cathode discharge tube LA occurs through the discharge path having the highest potential difference. At this time, the voltage applied between the poles of each filament is expressed by the following expression 6.

[0042]

[Equation 6]

As a result, there is a phase difference of 90 ° between VC and iC of the capacitor C14, iC × VC> 0.
When (iC x VC is greater than zero), the maximum potential is VA
D and VBD, and when iC × VC <0 (iC × VC is smaller than zero), the maximum potentials are VAC and VBC.

By the way, since VAB = 0, thermionic emission is effectively diffused from the D pole point to F1 while C1
If the phase of 4 is inverted, it will spread from the C pole to F1. According to the equations (5) and (6), while the self-excited inverter unit (3) operates for one cycle, in the hot cathode discharge tube LA, thermionic emission is F2 from the B pole, F2 from the A pole, and D pole. As a result, there are four types of discharge paths that diffuse to F1 from the F1 and C poles.

Therefore, since the hot cathode discharge tube has such a four-type discharge path, it is possible to prevent heat from being intensively emitted from one pole of the filament. As a result, the use efficiency of the filament is increased and the life of the filament is extended.

When the hot cathode discharge tube LA is removed from the lighting circuit section of FIG. 4, the equivalent circuit of FIG. 7 (1) is obtained. That is, the capacitor C13 and the diode D1
A DC voltage is supplied from the series circuit of 4 to the capacitor C13 by the diode D14, and the value of the impedance XC increases to "infinity" due to XC = 1 / 2πf, which results in an open circuit in which no current flows. Similarly, the series circuit of the capacitor C15 and the diode D15 is an open circuit in which no current flows. Also, from the diagram of FIG. 7 (2),
Diode D13, capacitor C14, diode D
Also in the circuit of 16, the diodes D13 and D16 are connected in opposite directions across the capacitor C14 so that no current flows. In this way, when the hot cathode discharge tube LA is removed from the lighting circuit section of FIG. 4, the lighting circuit becomes an open circuit as shown in FIG. 7C having infinite impedance. Therefore, when two or more lighting circuit parts are connected in parallel as shown in FIG. 6, even if one of the hot cathode discharge tubes connected to each lighting circuit part is removed, The effect that the lighting circuit section is not disturbed at all can be obtained. Even if the lighting circuit unit 4 of this embodiment is connected as shown in FIG. 5, the lighting circuit unit 4 operates equivalently to the lighting circuit unit shown in FIG.

When the self-excited inverter unit is operating, TL, which is the primary coil of the transformer TL2,
When a normal operating current of the self-excited inverter unit flows through 2-F1, a voltage of about 3V is generated across the secondary coils TL2-S1 and TL2-S2 of the transformer TL2, and two transistors Q3 are generated. And supply voltage to the base of Q4. In addition, a voltage of about 20V is generated at both ends of TL2-S3, and the thyristor S is supplied through the diode D3.
Supplied to CR1.

On the other hand, the thyristor SCR1 has a higher resistance value at both ends of the anode and the cathode and is electrically OF
While maintaining the F state, when the gate (GATE) receives a trigger (TRIGGER) signal, it is turned on and the resistance between both ends of the anode and cathode is reduced, which is the same as when the switch is turned on. The voltage between both ends of the cathode and the cathode becomes close to zero, and after being turned on once, it continues to be turned on until the voltage is cut off.
C. R (silicon, control, rectifier SILICON, CONTROL RECIFIF
ER).

Next, the operation of the overload protection circuit section 6 of FIG. 3 will be described. When an overcurrent flows in the lighting circuit unit 4 due to the end of life of the hot cathode discharge tube or misconnection, it is induced in the secondary coil TL3-S of the retractor TL3 in the self-excited inverter unit 3. Voltage will rise in the same way. When this voltage rises, the voltage rectified by the rectifying diode D11 and charged in the capacitor C8 by the resistors R20 and R15 also rises. The voltage of the capacitor C8 is diarc (DIAC)
When the voltage rises to the trigger voltage of 1, the diarc 1 triggers to supply a trigger signal to the gate of the thyristor SCR1 and the thyristor SCR1 is turned on. When thyristor SCR1 is turned on, transformer TL
The voltage of TL2-S3, which is the secondary coil of 2, is the internal voltage of diode D3 and thyristor SCR1.
To 2V, the voltage across TL2-S1 and TL2-S2 also drops at the same rate as TL2-S3, and 0,
It goes down to 1 to 0.3V. As a result, the base (BASE) voltage of the two high frequency output transistors Q3 and Q4 supplied by the TL2-S1 and TL2-S2 drops below the operating point, and the high frequency output transistors Q3 and Q4.
Stops working. At the same time, the capacitor C10 is also discharged through the series circuit of the diode D1 and the thyristor SCR1 so as not to be recharged, and the operation of the operation signal circuit unit 5 is interrupted. At the same time, the smoothing capacitor C3 in the booster circuit section is also discharged through the series circuit of the diode D21 and the thyristor SCR1, the operation of the booster circuit section is interrupted, and the entire circuit operation is interrupted to protect the circuit.

Next, FIG. 9 is a schematic block diagram showing an electronic discharge tube lighting device according to another embodiment of the present invention. Figure 9
, Reference numeral 11 is a noise filter, 2 is a constant voltage and T.I. H. D. (Total Harmonic Di
control circuit, 13 is a control circuit, 14 is an inverter circuit, 15 is an operation signal supply circuit,
16 and 17 are lighting circuits, 18 and 19 are lamps, 20
Is an overload protection circuit. Next, the operation of the apparatus shown in FIG. 9 will be described. The noise filter 11 rectifies the AC voltage from the AC power supply to turn the DC power supply into a constant voltage and T.V. H. D control circuit 1
2 and the control circuit 13. Constant voltage and T.I. H. When the DC power from the noise filter 11 is supplied, the D control circuit 12 supplies an operating voltage to the inverter circuit 14 at a low voltage to preheat the filament of the discharge tube at the initial stage of power-on, and then for a predetermined period. The operating voltage supplied to the self-excited inverter is gradually increased so that the discharge tube is lit at a low voltage, and after the lapse of the predetermined period, a constant constant voltage is supplied to stabilize the inverter circuit 14. To operate. Operation signal supply circuit 15
Operates at the initial stage of power-on and supplies an operation signal to the inverter circuit 14, and after the inverter circuit 14 operates for one cycle, the supply of this operation signal is interrupted. The inverter circuit 14 has a constant voltage and T.V. H. The operating voltage supplied from the D control circuit 12 is changed to a high frequency, and the lighting circuit 16,
Send to 17. The lighting circuits 16 and 17 convert the high frequency output from the inverter circuit 14 into a sine wave, and the lamp 18 and
Turn on 19. When an overcurrent flows in the lighting circuit section 4 due to the end of life of the hot cathode discharge tube or misconnection,
The overload protection circuit 20 outputs a signal to the operation signal supply circuit 15 to stop the operation of the inverter circuit 14. Further, in this case, the overload protection circuit 20 also outputs a signal to the control circuit 13 so that the constant voltage and the T. H. The operation of the D control circuit 12 is stopped.

[0051]

According to the present invention, in the initial stage of power-on, the operation voltage of the self-excited inverter is supplied at a low voltage to preheat the filament of the discharge tube by the operation of the booster circuit section which supplies the operation power to the self-excited inverter. Then, by gradually increasing the operating voltage of the self-excited inverter for a predetermined period, the discharge tube is lit at a low voltage to extend the life of the discharge tube, and after the lapse of the predetermined period, the self-excited booster circuit section is used. The operating voltage is supplied to the inverter at a constant constant voltage to stabilize the operation of the self-excited inverter, and when the input power supply changes within ± 20% due to fluctuations in the common power supply, the output change range of the discharge tube is ± Since the voltage and the current flow inside the discharge tube are stabilized by stabilizing within 3%, it is possible to extend the life and always maintain a constant illuminance.

Further, as in the conventional lighting device for a discharge tube, the problem that the thermoelectrons are intensively emitted from a specific position of the filament and the temperature at that position is remarkably increased to shorten the life of the discharge tube is solved. In order to do so, the filament of the discharge tube is alternately heated through at least four types of discharge paths by the action of the circuit that is simply configured by at least four discharge path dispersion diodes in the lighting circuit section. Electrons are emitted to improve the efficiency of use of the filament.

At this time, since the transition of the thermionic discharge path changes linearly, noise is not generated, and the filament heating voltage can be easily set only by the heating voltage adjusting capacitors of the two filaments, and the discharge can be performed. It is possible to improve the efficiency of use of the tube, extend the life of the discharge tube, and maximize energy saving.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a discharge tube lighting device using a self-excited inverter according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional inverter.

FIG. 3 is a circuit diagram showing a discharge tube lighting device according to an embodiment of the present invention.

FIG. 4 is a diagram showing a lighting circuit unit of the present embodiment.

5 is a diagram showing a circuit that operates equivalently to the lighting circuit unit of FIG.

6 is a diagram showing an example in which two or more lighting circuit units of FIG. 4 are connected in parallel.

FIG. 7 is a circuit diagram for explaining the operation of the lighting circuit of FIG.

8 is a diagram showing a block diagram (BLOOK DIAGMRAM) of the integrated circuit IC1 of FIG.

FIG. 9 is a schematic block diagram showing an electronic discharge tube lighting device according to another embodiment of the present invention.

[Explanation of symbols]

 1 DC power supply section 2 Booster circuit section 3 Self-excited inverter section Operation signal circuit section 4 Lighting circuit section 5 Operation signal circuit section 6 Overload protection circuit section 11 Noise filter 12 Constant voltage and T.V. H. D control circuit 13 control circuit 14 inverter circuit 15 operation signal supply circuit 16,17 lighting circuit 18,19 lamp 20 overload protection circuit

Claims (7)

[Claims] 1. A DC power supply unit for operating a booster circuit unit by supplying a DC power supply to the booster circuit unit, and an output from the booster circuit unit that is rectified by an output from the booster circuit unit and supplied as an operation power supply. Self-excited oscillating signal in the circuit connected in series between the hot cathode discharge tube and the connection point of the two output transistors of this self-excited inverter Detecting transformer and two secondary circuits used as base voltage supply to the two output transistors in the three secondary coils of the self-excited oscillation signal detecting transformer. The circuit is substantially connected to both ends of the remaining one secondary side coil other than the side coil, and when the lighting circuit section is overloaded at the end of its life of the hot cathode discharge tube, the circuit is substantially In the circuit connected between the overload protection circuit section for shutting off the power supply and the two power source capacitors that compose the self-excited inverter section together with the two output transistors, the hot cathode discharge tube and the self-discharge circuit are connected. From the lighting circuit excluding the transformer for detecting the excited oscillation signal and the resonance ejector, the filaments of the hot cathode type discharge tube are alternately discharged with the thermoelectrons through the four types of thermoelectron discharge paths. , And a lighting circuit unit configured to easily adjust the heating voltage of the filament of the hot cathode discharge tube, and immediately after a DC power source is turned on to the booster circuit unit,
The self-excited inverter unit is supplied with an initial voltage to such an extent that the hot cathode discharge tube is not lit, and then the filament is preheated for a predetermined period of time to gradually increase the operating voltage while When the tube is turned on and the operating voltage has finished rising after the predetermined period of time has passed, the self-excited inverter section has a stable constant voltage (even if there is a fluctuation in the input voltage or a fluctuation in the output load). Voltage), the filaments of the hot cathode discharge tube are alternately heated through four types of thermionic discharge paths, and the lighting circuit section is Two or more hot cathode type discharge tubes can be used by connecting them in parallel by connecting them to each lighting circuit section, and each lighting circuit section is connected to each hot cathode type. Discharge tube When removed, it has an infinite impedance, and since the lighting circuit section after this hot cathode discharge tube is removed is virtually the same as being separated from the circuit, the above two Any one of the hot cathode discharge tubes connected in parallel
An electronic discharge tube lighting device characterized in that even if one or more hot cathode discharge tubes are removed, the remaining hot cathode discharge tubes are not ill-inhibited. 2. A DC power supply unit that outputs a DC power supply obtained by rectifying an AC input voltage, a booster circuit unit that converts the DC power supply supplied from the DC power supply unit into a predetermined operating voltage, and the booster circuit. A self-excited inverter unit that converts the operating voltage supplied from the unit into a predetermined high frequency, and a lighting circuit unit that converts the high-frequency output from the self-excited inverter into a sine wave to light the discharge tube. Electronic discharge tube lighting device. 3. A DC power supply section for outputting a DC power supply obtained by rectifying an AC input voltage, a booster circuit section for converting the DC power supply supplied from this DC power supply section into a predetermined operating voltage, and this booster circuit. Self-excited inverter section that converts the operating voltage supplied from the unit to a predetermined high frequency, a lighting circuit section that converts the high-frequency output from the self-excited inverter into a sine wave to light the discharge tube, and this lighting circuit section An overload protection circuit section for stopping the operation of the self-excited inverter circuit section when a load occurs,
An electronic discharge tube lighting device comprising: 4. The electronic discharge tube lighting device according to claim 2, wherein the booster circuit unit senses a change in the DC power source that changes in proportion to a change in the AC input voltage. An electronic discharge tube comprising: an adjusting means (control means) for adjusting the operating voltage supplied to the self-excited inverter so that the operating voltage is always constant based on the output from the sensing means. Lighting device. 5. The electronic discharge tube lighting device according to claim 3, wherein the booster circuit unit is connected to the DC power supply unit, accumulates a voltage from the DC power supply unit, and stores the accumulated voltage. An electronic discharge tube lighting device comprising: a discharger for discharging, and a transistor connected to the discharger for controlling accumulation of a voltage in the discharger or discharge of a voltage from the discharger. 6. The electronic discharge tube lighting device according to claim 3 or 4, wherein the lighting circuit section alternately discharges thermoelectrons through a thermoelectron discharge path having four filaments of a hot cathode type discharge tube. An electronic discharge tube lighting device, characterized in that 7. The electronic discharge tube lighting device according to claim 3, 4 or 6, wherein the lighting circuit section includes two or more of the lighting circuit sections connected in parallel, and the lighting circuit section is provided with the heat A cathode type discharge tube can be connected and used, and the lighting circuit section has an infinite impedance when the connected hot cathode type discharge tube is removed. Since the lighting circuit section from which the hot cathode discharge tubes are removed is virtually the same as being separated from the circuit, any one of the plurality of hot cathode discharge tubes connected in parallel may be used. An electronic discharge tube lighting device, characterized in that even if one or more hot cathode discharge tubes are removed, lighting of the remaining hot cathode discharge tubes is not hindered.