JP2003068488A - Discharge lamp lighting device and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device to prevent a direct current from being applied to the discharge lamp. SOLUTION: An inverter circuit 15 turns on fluorescent lamp FL with a high frequency by inducing a high-frequency voltage in the secondary coil Tr1b. A direct current voltage is generated from the direct current generated in the fluorescent lamp FL in a capacitor C6 for direct-current blocking. The capacitor C7 for cancellation is charged in the polarity opposite to that of the capacitor C6 for direct-current blocking by rectifying an electric charge of the capacitors C11, C12 for charging by means of diodes D6, D7. The voltage of the capacitor C6 for the direct-current blocking is biased to 0V by the voltage of the capacitor C7 for cancellation to eliminate the direct current, and a one-side dark discharge is prevented by preventing deviations of mercury in the fluorescent lamp FL due to moving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device and a lighting device which prevent a direct current from flowing through a discharge lamp.

[0002]

2. Description of the Related Art Conventionally, as a discharge lamp lighting device of this type, for example, a fluorescent lamp is used as a discharge lamp in an inverter circuit having an insulating transformer for insulation from a switching element and an output side connected to a secondary winding. Connected. Further, a direct current cut capacitor for cutting direct current is connected between the fluorescent lamp and the secondary winding of the insulation transformer, and a resistor is connected in parallel to the direct current cut capacitor.

Then, the switching element is oscillated at a high frequency to generate a high-frequency alternating current in the inverter circuit, which is insulated by an insulating transformer and the direct-current cutting capacitor is used to cut the direct current to apply a high-frequency alternating voltage to the fluorescent lamp.
The fluorescent lamp is started and turned on.

[0004]

However, even if a high-frequency AC voltage is applied from the inverter circuit to the discharge lamp, the fluorescent lamp has a non-linear characteristic, so that when the duty of the switching element is asymmetrical, Even if the high-frequency alternating current generated by controlling the switching element has the same positive and negative electric energy, if the positive and negative waveforms are different, a direct current may be generated. Then, a direct current flows through the direct current cut capacitor and a direct current voltage is charged. This DC voltage is then applied to the lamp.

Further, when the direct current voltage is applied to the fluorescent lamp in this manner, the polarity of the direct current voltage is constant, mercury moves to the negative electrode side of the direct current of the fluorescent lamp, and argon discharge or the like occurs on the positive electrode side. The discharge lamp has an unfavorable problem such as occurrence of dark discharge.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a discharge lamp lighting device and a lighting device which prevent application of a DC voltage to the discharge lamp.

[0007]

The discharge lamp lighting device according to claim 1 has a primary winding and a secondary winding electrically connected to each other, and an insulation in which the discharge lamp is connected to the secondary winding. An inverter means provided with a transformer for lighting the discharge lamp; a parallel circuit of a direct current cut capacitor and an impedance element capable of passing a direct current, connected between the secondary winding and the discharge lamp; It is equipped with a DC canceling means for canceling, and the DC is cut by the DC cutting capacitor connected between the secondary winding of the insulation transformer of the inverter means and the discharge lamp, and the DC voltage is charged in the DC cutting capacitor. In addition, even if direct current flows through the impedance element in parallel with this direct current cut capacitor and direct current voltage is generated, direct current canceling means Since not applied to direct current discharge lamp to cancel more DC voltage, direct current discharge lamp is prevented from adverse effects of being applied.

A discharge lamp lighting device according to a second aspect of the present invention is the discharge lamp lighting device according to the first aspect, wherein the DC canceling means includes a charging capacitor and a DC cutting capacitor connected in parallel to the discharge lamp. On the other hand, it is equipped with a canceling capacitor that is connected in series and that is charged in the opposite polarity to the charge that is charged in the DC cutting capacitor by the charge from the charging capacitor, and is connected in parallel to the discharge lamp. The charging capacitor is charged with the electric current of the direct current flowing through the discharge lamp, and the charging capacitor is charged to the canceling capacitor in the opposite polarity to that charged in the DC cutting capacitor. Cancels the DC voltage applied to the lamp.

A discharge lamp lighting device according to a third aspect of the present invention is the discharge lamp lighting device according to the first aspect, wherein the DC canceling means is connected in parallel to the discharge lamp and has a polarity opposite to a DC current flowing through the discharge lamp. With the connected rectifying means, the rectifying means cancels the direct current flowing through the discharge lamp.

A discharge lamp lighting device according to a fourth aspect is the discharge lamp lighting device according to the first aspect, wherein the DC canceling means is connected in series to the DC cutting capacitor.
It is equipped with an impedance element capable of passing a direct current and a rectifying means connected in parallel to this impedance element and having a polarity opposite to that of the direct current flowing through the discharge lamp. The DC current flowing through the discharge lamp via the generated impedance is canceled.

A discharge lamp lighting device according to a fifth aspect of the present invention is the discharge lamp lighting device according to the first aspect, wherein the DC canceling means comprises a switching means for switching the polarity of the inverter means applied to the discharge lamp. By switching the polarity of the inverter means applied to the lamp, the direct current voltage in the same direction is prevented from being applied to the discharge lamp, and the polarity of the direct current applied changes when considered within a certain time range. Cancels the DC voltage applied to.

A lighting device according to a sixth aspect comprises the discharge lamp lighting device according to any one of the first to fifth aspects; and a fixture main body to which a discharge lamp to be lit by the discharge lamp lighting device is mounted. And, each effect is played.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a discharge lamp lighting device of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view showing the appearance of the illuminating device. As shown in FIG. 2, the illuminating device 1 has a reflecting surface 3 formed on the lower surface of the main body 2 of the fixture, and the lamps are provided at both ends of the reflecting surface 3. Sockets 4 and 4 are formed, a fluorescent lamp FL as a discharge lamp is mounted between the lamp sockets 4 and 4, and the discharge lamp lighting device 5 shown in FIG. 1 is housed inside.

FIG. 1 is a circuit diagram showing a discharge lamp lighting device. As shown in FIG. 1, the discharge lamp lighting device 5 has a commercial AC power source e connected to a filter capacitor C1 and rectified by the capacitor C1. Connect the input terminal of full-wave rectifier circuit 11 as a means, and connect capacitor C2 to the output terminal of this full-wave rectifier circuit 11.
And a partial smoothing circuit 12 for valley filling is connected in parallel to this capacitor C2. In addition, this partial smoothing circuit 12
Is a charging capacitor C3 at the output terminal of the full-wave rectifier circuit 11,
Connect a series circuit of inductor L1 and diode D1,
The diode D2 is connected in parallel to the series circuit of the charging capacitor C3 and the inductor L1, and the diode D3 is connected to the connection point of the inductor L1 and the diode D1.

Then, the DC power supply 14 is constituted by these,
A monolithic inverter circuit 15 as an inverter means is connected to the DC power supply 14.

Further, in the inverter circuit 15, the capacitor C2 is connected in series with the primary winding Tr1a of the inverter transformer Tr1 which is an insulating transformer, the inductor L2 and the collector and emitter of the transistor Q1 as a switching element. The resonance capacitor C4 is connected in parallel to the series circuit of the primary winding Tr1a and the inductor L2.
The parallel resonant circuit 16 is connected by C4. Further, the control circuit 18 is connected to the base of the transistor Q1.

On the other hand, the secondary winding T of the inverter transformer Tr1
A load circuit 21 is connected to r1b, and this load circuit 21 is
A parallel circuit of a DC cutting capacitor C9 and a resistor R1 as an impedance element, and a canceling capacitor of a DC canceling means 22 connected in series to this parallel circuit.
One ends of the filaments FL1 and FL2 of the fluorescent lamp FL are connected via C7 and parallel to the canceling capacitor C7, the diode D6 and the diode D7 of the opposite polarity that block the flow of the direct current flowing through the load circuit 21. The series circuit of is connected. The direction of the direct current flowing through the load circuit 21 is known in advance.

Further, a starting capacitor C8 is connected between the other ends of the filaments FL1 and FL2, and a series circuit which also functions as a voltage divider of the charging capacitor C11 and the charging capacitor C12 of the DC canceling means 22 is connected. Has been done. The connection point between the charging capacitor C11 and the charging capacitor C12 is the diode D6 and the diode D7.
Is connected to the connection point of.

Next, the operation of the above embodiment will be described.

First, a base current is supplied to the base of the transistor Q1 by the control circuit 18 to turn on the transistor Q1. Then, when the transistor Q1 performs a switching operation and oscillates, the inductor L2, the primary winding Tr1a of the inverter transformer Tr1 and A high frequency voltage is generated by the resonance action with the resonance capacitor C4, and a high frequency voltage is also induced in the secondary winding Tr1b.

When the transistor Q1 is turned on, a current flows through the primary winding Tr1a of the inverter transformer Tr1 and a current flows through the charging capacitor C3, the inductor L1 and the diode D3 to charge the charging capacitor C3. Then, a DC voltage lower than the peak value of the pulsating current voltage from the full-wave rectification circuit 11 can be stored in the charging capacitor C3.

Here, the pulsating current voltage of the full-wave rectifier circuit 11 will be described separately in a section where it is higher than the charging voltage of the charging capacitor C3 and a section where it is lower than the charging voltage.

First, when the transistor Q1 of the inverter circuit 15 is turned on at an arbitrary time portion in a section where the pulsating current voltage of the full-wave rectifier circuit 11 is higher than the charging voltage of the charging capacitor C3, the primary winding Tr1a of the inverter transformer Tr1 is turned on. Most of the current is supplied to the capacitor C1 and part of it is supplied from the capacitor C2, and the charging capacitor C3 is charged. In the section where the peak value of the full-wave rectifier circuit 11 is high, the charging capacitor C3 does not discharge to the inverter circuit 15 side. Energy corresponding to the current supply from the capacitors C1 and C2 flows as an input current from the commercial AC power supply e side. Then, the operation is performed so as to accompany the switching operation of the transistor Q1 in response to the change in the pulsating current voltage, and a small and equal amplitude of the high frequency of the inverter operation of the inverter circuit 15 along the AC voltage sine wave value is a full wave. The rectifier circuit 11 is superposed on all sections where the peak value is high.

Next, in a section where the peak value of the full-wave rectifier circuit 11 is low, when the pulsating sinusoidal voltage of the full-wave rectifier circuit 11 starts to decrease with respect to the charging voltage of the charging capacitor C3, the transistor Q1 turns on. When turned on, the current to the primary winding Tr1a of the inverter transformer Tr1 is first supplied from the capacitor C2, and at the same time, the current flows through the path of the charging capacitor C3, the inductor L1, the diode D3 and the transistor Q1 and the charging capacitor C3. Are charged and the DC voltage becomes lower than the peak value of the pulsating current voltage from the full-wave rectification circuit 11. Since the capacity of the capacitor C2 is insufficient to give the energy required by the inverter circuit 15, the voltage of the capacitor C2 decreases as the current flowing through the primary winding Tr1a increases after the transistor Q1 is turned on. Then, the capacitor C1 supplies energy to the inverter circuit 15 which is insufficient in the capacitor C2 from the time when the voltage of the capacitor C2 drops to the voltage of the capacitor C1.

Then, from the capacitor C1 to the inverter circuit
For the energy supply to 15, the energy corresponding to this is made to flow from the commercial AC power source e side as an input current.

On the other hand, the charging voltage of the charging capacitor C3 is the inductor L2 and the primary winding Tr1 of the inverter transformer Tr1.
Energy release is delayed due to the transient impedance of a,
The energy is released immediately before the transistor Q1 is turned off. When the transistor Q1 is turned off, the energy of the inductor L1 is transferred to the diode D2, the charging capacitor C3, and the inductor L1 in the closed circuit.
Released to C3. Also, by turning off the transistor Q1,
The resonance capacitor C4 resonates with the inductor L2 and the series circuit of the primary winding Tr1a of the inverter transformer Tr1.
Then, this resonant current is generated by the diode D1, the diode D
3, inductor L2, inverter transformer Tr1 primary winding Tr
The current flows in the path of 1a, the capacitor C2 and the diode D1, and the capacitor C2 is charged to generate an oscillating voltage.

Then, as the voltage of the capacitor C1 decreases with respect to the charging voltage of the charging capacitor C3, the voltage of the capacitor C2 decreases, and the amplitude of the inductor L2 and the capacitor C2 increases. Further, although the input current decreases, the current continuously flows.

As described above, the continuous input current from the commercial AC power source e prevents the harmonic component from intervening in the input current of the inverter circuit 15.

The inverter circuit 15 includes a resonance capacitor C4, an inductor L2 of the parallel resonance circuit 16 and an inverter transformer when the transistor Q1 is turned on.
Current flows through the primary winding Tr1a of Tr1 and the inverter transformer T
A voltage is induced in the secondary winding Tr1b of r1. Then, the resonance capacitor C4, the inductor L2 and the inverter transformer
Due to the parallel resonance of the primary winding Tr1a of Tr1, a high frequency voltage is induced in the secondary winding Tr1b, and the fluorescent lamp FL is lit at high frequency.

Here, the reason why the DC current flows through the load circuit 21 on the secondary winding Tr1b side of the inverter transformer Tr1 will be described.

Since the duty ratio of the transistor Q1 is unbalanced and the inverter transformer Tr1 is an insulated type in which the inverter transformer Tr1 is not electrically connected, the one-stone inverter circuit 15 has a secondary winding Tr1b of the inverter transformer Tr1. ,
As shown in FIG. 3, although the positive-side electric energy P and the negative-side electric energy N are equal, high-frequency alternating currents having different peak values and different waveforms on the positive and negative sides are induced. Since the power amount P on the positive side and the power amount N on the negative side are equal, this secondary winding Tr
The high frequency AC voltage waveform induced in 1b contains no DC component.

However, since the fluorescent lamp FL has a non-linear relationship between the voltage and the current as shown in FIG. 4, the voltage value does not rise more than the predetermined value Vc even if the current value rises more than the predetermined value in absolute value. , The current of the fluorescent lamp FL is as shown in FIG.
A protruding portion D is generated on the negative side, and a current corresponding to this protruding portion D flows as a DC component into the load circuit 21, and a DC voltage is generated. Further, when the direct current is applied to the fluorescent lamp FL in this way, the mercury in the fluorescent lamp FL moves in the direction of the negative electrode filament FL2 of the direct current voltage, and the argon discharge on the positive electrode filament FL1 side with less mercury.
That is, dark discharge occurs, and the fluorescent lamp FL becomes so-called one-side dark discharge.

Therefore, in the case of a circuit in which a DC current flows in the direction shown by the arrow in FIG. 1, the DC cut capacitor C6 is charged with the polarity shown. Further, the voltage across the lamp is divided by the charging capacitor C11 and the charging capacitor C12, rectified by the diode D6 and the diode D7, and charged to the canceling capacitor C7 in the opposite polarity to the DC cutting capacitor C6. To do. Then, the voltage of the canceling capacitor C7 is biased so that the voltage of the DC cutting capacitor C6 becomes 0 V, the DC voltage is eliminated, the bias of the fluorescent lamp FL due to the movement of mercury is prevented, and the one-side dark discharge is performed. To prevent.

Next, another embodiment will be described with reference to FIG.

FIG. 6 is a circuit diagram showing a discharge lamp lighting device of another embodiment, in which a DC canceling device 25 is provided in place of the DC canceling device 22 of the discharge lamp lighting device 5 shown in FIG. .

The DC canceling means 25 is connected between the other ends of the filaments FL1 and FL2 of the fluorescent lamp FL, and has a resistor R2 and a diode D8 as a rectifying means having a reverse polarity in the direction of reverse blocking the DC current. It is composed of a series circuit.

The basic operation is the same as that of the discharge lamp lighting device 5 shown in FIG. 1, except that the diode D8 biases the direct current in the direction opposite to the direct current to bring the direct current to 0 or close to 0, and It cancels the direct current of the lamp FL.

Further, another embodiment will be described with reference to FIG.

FIG. 7 is a circuit diagram showing a discharge lamp lighting device according to another embodiment, in which a DC canceling means 26 is provided instead of the DC canceling means 22 of the discharge lamp lighting device 5 shown in FIG. .

The DC canceling means 26 is connected in series to the DC cutting capacitor C6,
It is composed of a resistor R3 and a series circuit of a diode D9 as a rectifying means of reverse polarity in the direction of reverse blocking the direct current.

The basic operation is similar to that of the discharge lamp lighting device 5 shown in FIG. 1, except that the diode D9 biases the direct current in the direction opposite to the direct current to bring the direct current to 0 or close to 0, and the fluorescent light is emitted. It cancels the direct current of the lamp FL.

Further, another embodiment will be described with reference to FIG.

FIG. 8 is a circuit diagram showing a discharge lamp lighting device of another embodiment, in which a DC canceling device 27 is provided in place of the DC canceling device 22 of the discharge lamp lighting device 5 shown in FIG. .

Further, the DC canceling means 27 connects one end of each of the filaments FL1 and FL2 of the fluorescent lamp FL to
A relay switch Ry as switching means that enables switching connection to the opposite side of the secondary winding Tr1b of the inverter transformer Tr1.
1 and Ry2 are provided.

The basic operation is the same as that of the discharge lamp lighting device 5 shown in FIG. 1, but the relay switches Ry1 and Ry2 are switched at predetermined intervals to switch the direction of the direct current flowing through the load circuit 21. , The direction of the direct current voltage applied to the fluorescent lamp FL is reversed, and the relay switches Ry1 and Ry2 are reversed and returned to the original state as one cycle, and the so-called direct current is canceled in the AC state for a long time. .

[0047]

According to the discharge lamp lighting device of the first aspect of the present invention, the direct current is cut by the direct current cut capacitor connected between the secondary winding of the insulation transformer of the inverter means and the discharge lamp to cut the direct current. Even if a DC voltage is charged to the discharge lamp or DC is generated in the impedance element in parallel with this DC cut capacitor, the DC voltage is canceled by the DC canceling means so that the DC voltage is not applied to the discharge lamp. It is possible to prevent an adverse effect caused by applying a direct current to the.

According to the discharge lamp lighting device of the second aspect,
In addition to the discharge lamp lighting device according to claim 1, a charging capacitor connected in parallel to the discharge lamp is charged with a charge of a direct current flowing through the discharge lamp, and the charge charged in the charging capacitor is cut to a direct current. The DC voltage applied to the discharge lamp can be canceled by charging the canceling capacitor in the opposite polarity to the charge charged in the working capacitor.

According to the discharge lamp lighting device of the third aspect,
In addition to the discharge lamp lighting device according to claim 1, since the DC canceling means comprises a rectifying means connected in parallel to the discharge lamp and having a polarity opposite to that of the DC current flowing through the discharge lamp, discharge by the rectifying means The direct current flowing through the lamp can be canceled.

According to the discharge lamp lighting device of the fourth aspect,
In addition to the discharge lamp lighting device according to claim 1, the direct current canceling means is connected in series to the direct current cut capacitor, is connected in parallel with an impedance element capable of passing direct current, and is connected in parallel to this impedance element and flows into the discharge lamp. Since the rectifying means connected to the opposite polarity to the direct current is provided,
The rectifying means can cancel the DC current flowing through the discharge lamp via the impedance connected in parallel to the DC cutting capacitor.

According to the discharge lamp lighting device of the fifth aspect,
In addition to the discharge lamp lighting device according to claim 1, since the DC canceling means includes a switching means for switching the polarity of the inverter means applied to the discharge lamp, the discharge lamp can be switched by switching the polarity of the inverter means. It is possible to prevent the DC voltage applied to the discharge lamp from being applied to the discharge lamp because the DC voltage applied to the discharge lamp is prevented from being applied to the discharge lamp and the polarity of the DC current flowing changes within a certain time range.

According to the sixth aspect of the present invention, there is provided a lighting apparatus equipped with a discharge lamp which is lit by the discharge lamp lighting apparatus according to any one of the first to fifth aspects.
Each effect can be exhibited.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is a perspective view showing the outer appearance of the above lighting device.

FIG. 3 is a waveform diagram showing an output voltage of a secondary winding of the same inverter transformer.

FIG. 4 is a graph showing voltage-current characteristics of the same fluorescent lamp.

FIG. 5 is a waveform diagram showing a lamp current of the above fluorescent lamp.

FIG. 6 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the above.

FIG. 7 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the above.

FIG. 8 is a circuit diagram showing a discharge lamp lighting device of still another embodiment of the same.

[Explanation of symbols] 1 Lighting device 2 instrument body 5 Discharge lamp lighting device 15 Inverter circuit as an inverter means 22, 25, 26, 27 DC canceling means C6 DC cut capacitor C7 cancel capacitor C11, C12 charging capacitor D8, D9 Diode as rectifying means Fluorescent lamp as FL discharge lamp R1 resistance as impedance element Relay switch as Ry1, Ry2 switching means Tr1 Inverter transformer as isolation transformer Tr1a Primary winding Tr1b secondary winding

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3K072 AA02 AC02 AC11 AC13 AC13 BA03                       CA01 CA16 DB03 DB09 DC07                       DC08 GA01 GB04 GC04 HA02                       HA07 HA08

Claims (6)

[Claims] 1. Inverter means having an electrically connected primary winding and secondary winding, an insulating transformer having a secondary winding connected to a discharge lamp, and illuminating the discharge lamp; A parallel circuit of a direct current cut capacitor and an impedance element capable of passing a direct current, which is connected between the line and the discharge lamp; and a direct current canceling means for canceling the direct current voltage applied to the discharge lamp. Discharge lamp lighting device. 2. The direct current canceling means is connected in parallel to the discharge lamp, and the direct current cut capacitor is connected in series to the direct current cut capacitor so that the direct current cut capacitor is charged by the charge from the charging capacitor. The discharge lamp lighting device according to claim 1, further comprising a canceling capacitor that is charged in a polarity opposite to that of the electric charge that is generated. 3. The discharge lamp according to claim 1, wherein the DC canceling means includes a rectifying means connected in parallel to the discharge lamp and having a polarity opposite to that of a DC current flowing through the discharge lamp. Lighting device. 4. The direct current canceling means is connected in series to the direct current cut capacitor and is connected in parallel with an impedance element capable of passing direct current and has a polarity opposite to that of the direct current flowing through the discharge lamp. The discharge lamp lighting device according to claim 1, further comprising a rectifying means connected thereto. 5. The discharge lamp lighting device according to claim 1, wherein the DC canceling means includes switching means for switching the polarity of the inverter means applied to the discharge lamp. 6. A lighting device comprising: the discharge lamp lighting device according to any one of claims 1 to 5; and a fixture main body to which a discharge lamp to be lit by the discharge lamp lighting device is mounted. .