JPH0256798B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes an electronic circuit method using a nonlinear capacitor made of a polycrystalline ceramic composition containing barium titanate as a main component and zirconia as a subcomponent. This invention relates to a discharge lamp lighting device for instantaneous lighting of a lamp.

Compared to incandescent light bulbs, fluorescent light bulbs are extremely energy-efficient and are widely used for home and industrial purposes when it comes to providing the same level of illumination. In addition, the glow lamps became fatigued and required periodic replacement.

In recent years, lighting devices using electronic circuits have been put into practical use in place of glow lamps, and the drawbacks of glow lamps have been improved. Because high voltage is required, the electronic circuit becomes complicated and the cost of the device increases. In addition, as energy-saving lamps are put into practical use, lighting failures occur, and there are still aspects that do not allow them to make a sufficient contribution to industry.

Among lighting systems using electronic circuits, lighting devices that use nonlinear capacitors have simple circuits and are superior in terms of cost and performance.
Although these capacitors have been commercialized as shown in Figure 1 and shown in Japanese Patent Publication No. 19181 and Japanese Patent Publication No. 48-28726, they do not fully demonstrate the performance of nonlinear capacitors.

In FIG. 1, the semiconductor switch 3 is turned on at a voltage _V1 to enter a conductive state as shown in FIG. 2, thereby preheating the filaments 1a and 1b. This voltage V ₁ is applied to the nonlinear capacitor 4 by voltage division with the resistor 6, and a reverse charge is charged. The stabilizer 2 turns off when the delayed current becomes less than the holding current of the semiconductor switch 3;
A voltage corresponding to V ₂ is applied to the nonlinear capacitor 4, and a back electromotive force V ₃ is induced from the ballast 2 due to the rapid current cutting action of the nonlinear capacitor 4. When the filament is sufficiently preheated, the voltage V ₃ causes a discharge. The electric light starts discharging.

However, in the conventional example, the nonlinear capacitor was
Ba(TiSn)O ₃ as revealed in Publication No. 55-56621
As shown by curve _B2 in FIG. 3, the pulse voltage decreases rapidly near 30 to 35°C.

Furthermore, since a resistor 6 is connected in series with the nonlinear capacitor 4, this causes a drop in pulse voltage, which causes lighting failures at low and high temperatures.

The present invention applies to resistor 6 and diode 5 in FIG.
Instead, a semiconductor element with bidirectional switching function is used, and Ba (TiZr), which has good high temperature characteristics, is used.
This device is characterized by the use of a nonlinear capacitor made of O ₃ ceramic, which not only prevents the pulse voltage from decreasing at low temperatures of -10 to 20 degrees Celsius, but also prevents the pulse voltage from decreasing at 30 to 35 degrees Celsius. 65-70
We have expanded the temperature range to obtain a high pulse voltage up to ℃, and have also discovered the additional effect of eliminating the small pulses generated due to the presence of the resistor 6, as well as the humming noise generated by the application of alternating voltage to the nonlinear capacitor. It is something that

A ferroelectric material with a high dielectric constant and a small coercive electric field is desirable as a material for a nonlinear capacitor used in a lighting device for a discharge lamp, and BaTiO ₃ with a perovskite structure satisfies these conditions.
is currently optimal, but the Kyuri point 5 at 120℃
It has a crystal transformation point near °C, and the high pulse voltage required for lighting is also temperature dependent.

Figure 3 shows a nonlinear capacitor using Ba(TiZr)O ₃ ceramic with a ceramic diameter of 13.8 mmφ, an electrode diameter of 12.0 mmφ, and a thickness of 0.05 _mmt . , A ₀₅ is R
= 500Ω, A ₁ is R = 1kΩ, A ₂ and B ₂ are R = 2kΩ,
A ₄ shows the temperature dependence of the pulse voltage (corresponding to V ₃ in FIG. 2) generated across the nonlinear capacitor when R=4 kΩ. In addition, Figure 4 shows the temperature dependence of the coercive electric field Ec obtained from the P-E hysteresis of a _nonlinear capacitor. is a conventional nonlinear capacitor made of Ba(TiSn)O ₃ ceramic.

Nonlinear capacitors exhibit P-E hysteresis with excellent squareness ratio, as shown in FIG. As shown in Figure 3 _{, the pulse voltage of a nonlinear capacitor was found to be significantly improved by adding Zr to BaTiO 3 .} This shows an example of the characteristics of a composition system in which 8 mol % of Zr was substituted.

The sudden change point of the pulse voltage is at 65 to 70°C in Fig. 3, and can be changed depending on the amount of Zr added. When the amount of Zr added is decreased, the sudden turning point shifts to the low temperature side, and when the amount added is increased, the Curie point moves to the low temperature side, so 65~
It was difficult to raise the temperature to 70°C or higher. Furthermore, on the low temperature side, since the coercive voltage Ec of the nonlinear capacitor has a large temperature dependence as shown in FIG. 4, it has been found that the pulse voltage characteristics can be improved by changing the circuit constants, especially the resistor 6 shown in FIG. In other words, near the current saturation point Es, the transient capacitance found from Figure 5 corresponds to 2.7 to 3.0 μF, and the impedance at this time is around 1 kΩ, and the series resistor 6 of the circuit in Figure 1 is , it has the potential to become an extremely large load as a voltage dividing resistor. In other words, the voltage when the semiconductor switch in Figure 1 turns on
V ₁ is applied to the nonlinear capacitor 4 and the resistor 6, and when R of the resistor 6 is 1 kΩ, the voltage applied to the nonlinear capacitor 4 is transiently approximated to V ₁ /2. For a discharge lamp lighting device, the normal voltage _V1 in Figure 1 must be set lower than the peak value of the power supply and higher than the discharge tube voltage during discharge of the discharge lamp.For example, in the case of a 30W fluorescent lamp, it should be set around 100V. , the resistor 6 in FIG. 1 is set to 2 to 3 kΩ.
As shown in Figure 6, in the circuit of Figure 1, the pulse
V ₃ causes the discharge lamp to start discharging and turn on.

Furthermore, even after the light is turned on, current flows in the forward and reverse directions through the diode 5 and resistor ₆ shown in FIG. If the resistor 6 in FIG. 1 is small, it does not limit the current flowing through the nonlinear capacitor during the period from a to b in FIG. 6, so a small pulse b'' is generated as shown by the dotted line in FIG. 7.b' At this point, the semiconductor switch 3 shown in FIG. 1 is turned on, and the upper half of FIG. 6 is not discharged, but only the lower half of the wave is discharged.

Therefore, in order to limit the current flowing through the nonlinear capacitor 4, a series resistance of 2 to 3 kΩ is required in Fig. 1, and as shown in Fig. 3, the temperature dependence of the pulse voltage becomes extremely large in the low temperature region. . The drop in pulse voltage at this low temperature section is
For example, when the resistor 6 is 1 kΩ, the voltage applied to the nonlinear capacitor 4 is V ₁ /2 as described above. If the voltage applied to the nonlinear capacitor is V, it will be P-E hysteresis as shown by the solid line in Figure 8,
The amount of residual polarization is Pr′.

From FIG. 4, it is estimated that the hysteresis characteristic of the nonlinear capacitor is as shown in FIG. 8 at 20°C, and as shown in FIG. 9 near -20°C, and the amount of residual polarization is Pr''.

As the resistance shown in FIG. 1 increases, the residual polarization amount Pr' near room temperature decreases as shown in FIG. 4, so the pulse voltage decreases. This is clear from the results shown in FIG. Furthermore, when the temperature drops to −20℃, Ec becomes the fourth
As it increases as shown in the figure, the amount of spontaneous polarization Pr'' becomes significantly smaller, and the pulse voltage decreases significantly.

Coercive voltage Ec of the nonlinear capacitor at this low temperature side
In order to reduce the apparent increase in , it is conceivable to reduce the thickness of the nonlinear capacitor element, but this is not preferable because the generated negative pulse voltage may cause dielectric breakdown of the nonlinear element itself.

In the present invention, by replacing the resistor 6 and diode 5 shown in FIG. 1 with semiconductor switches, the temperature dependence of the pulse voltage can be improved and the pulse after lighting can also be erased. An example thereof is shown in FIG.

In FIG. 10, the turn-on voltage of the bidirectional thyristor 7 is set higher than the tube voltage during discharge of the discharge lamp,
V ₁ in FIG. 11 is set to be lower than the voltage applied to voltage dividing resistors R ₁ +R ₂ before discharge. For example, for a 30W fluorescent lamp, set it to 90 to 100V.
The semiconductor switch 3 ₁ is set to turn on at a voltage V _BO higher than V ₁ , and the semiconductor switch 3 1 is set to turn on at a voltage V BO higher than V 1 .
It is preferable to use a unidirectional or bidirectional thyristor.

Hereinafter, the operating state of the present invention will be explained in detail with reference to FIGS. 10 and 11. At voltage V ₁ in FIG. 11, semiconductor switch 7 is turned on and voltage V ₁ is applied to nonlinear capacitor 4.
Therefore, a pulse V ₃ ' is generated, and at V _BO the semiconductor switch 3 ₁ is turned on, heating the filaments 1a and 1b of the discharge lamp. The semiconductor switch 31 is turned off when the current, which lags behind the ballast 2, becomes smaller than the holding current of the semiconductor switch ₃₁ . At this time, a voltage V ₁ ' is suddenly applied to the nonlinear capacitor 4, and a pulse V ₃ is generated.

The diode of semiconductor switch 3 ₂ is a pulse voltage
It has a withstand voltage of V ₃ , and is a semiconductor switch 3 ₁
The purpose is to block the operation at pulse _V3 . The tube voltage of the discharge lamp that started discharging by the pulse _V5 is lower than the turn-on voltage of the semiconductor switch 7, so it does not turn off, and after the start of discharge, no current flows through the nonlinear capacitor 4, so the pulse as shown in FIG. No voltage V ₄ is generated and no humming noise is generated.

R ₁ and R ₂ in FIG. 10 are the semiconductor switch 7.
The semiconductor switch ₃₁ uses the breakdown voltage of the thyristor, but adjusts the gate voltage to set V _BO to a value greater _than V ₁ and less than V _{3 .} The same is true even if

In addition, in the embodiment shown in FIG. 10, a three-terminal triax (bidirectional thyristor) was used.
It is clear that similar effects can be obtained with a two-terminal bidirectional thyristor.

Also, regarding the temperature characteristics of the pulse voltage, the turn-on voltage V ₁ of the semiconductor switch 7 is larger than the coercive voltage Ec of the nonlinear capacitor 4, so Ec shows 58V at -20°C from Fig. 4.
In the case of a 30W fluorescent lamp, V ₁ is set to 90 to 100V, so the amount of residual polarization is approximately equal to Pr in Figure 9, and the pulse temperature dependence in the low temperature region is as shown in Figure 3.
It exhibits characteristics extremely close to A ₀ characteristics, and no drop in pulse voltage is observed even at low temperatures.

As described above, in the discharge lamp lighting device according to the present invention, by using Ba(TiZr)O ₃ as the main component as the composition of the nonlinear capacitor, not only the pulse voltage characteristics on the high temperature side are significantly improved, but also the nonlinear capacitor is By connecting semiconductor elements with bidirectional switching functions as shown in Figure 10,
It has the remarkable effect of improving the temperature characteristics on the low-temperature side and eliminating the humming noise that occurs when lighting, and by easily obtaining a pulse voltage of 1000V at around room temperature, it is possible to improve the temperature characteristics of fluorescent lamps. It lights up fully within one second, and compared to conventional glow bulbs, it can be lit almost instantaneously in the range of -20 to 80°C.

Ba (TiZr), the main component of nonlinear capacitors
It can be reasonably assumed that equivalent effects can be expected even if a small amount of Ba is replaced with Ca, Sr, Pb, etc., or a portion of Ti, Zr is replaced with Sn, etc. in an O ₃ -based composition. It is.

As described above, the present invention makes full use of the performance of a nonlinear capacitor, and its ability to exhibit its effects has great industrial value.

[Brief explanation of drawings]

Figure 1 is a conventional discharge lamp circuit diagram, Figures 2, 6, and 7 are voltage waveform diagrams applied to the nonlinear capacitor in the circuit example of Figure 1, and Figure 3 is the discharge lamp lighting of Figure 1. Figure 4 is the coercive voltage-temperature characteristic diagram of a nonlinear capacitor, Figure 5 is a hysteresis characteristic diagram of a nonlinear capacitor, and Figures 8 and 9 are A hysteresis characteristic diagram of a nonlinear capacitor in a conventional discharge lamp lighting circuit, FIG. 10 shows a diagram of a discharge lamp lighting circuit of the present invention, and FIG. 11 shows a voltage waveform diagram applied to the nonlinear capacitor of the discharge lamp lighting circuit of FIG. , 1st
Figure 1A is an enlarged view of a in Figure 11, and Figure 1B is an enlarged view of b. 1: discharge lamp, 2: inductive ballast, 3: semiconductor switch, 4: nonlinear capacitor, 5: diode, 6: resistor, 7: bidirectional thyristor.

Claims (1)

[Claims] 1 It has an inductive ballast connected in series with the discharge lamp and a semiconductor switch connected in parallel with the discharge lamp, and further includes a polycrystalline ceramic composition mainly composed of barium titanate and zirconia as an admixture. A discharge lamp lighting device characterized in that a nonlinear capacitor added as a component and a semiconductor switch having a bidirectional switching function are connected in series and connected in parallel to a discharge lamp.