JPH0118555B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge lamp lighting device that is lightweight and capable of stable discharge.

Discharge lamps generally have negative lighting voltage-current characteristics, so it is necessary to insert an impedance component such as an inductive ballast or resistor into the lighting circuit to control the lamp current to an appropriate value, and to In order to start the lamp, it was necessary to apply the high voltage pulse required for lamp starting between the lamp discharge electrodes.

When an inductive ballast is used to control the lamp current, it has the disadvantage that the ballast is heavy and cannot make the discharge lamp device smaller and lighter.On the other hand, when a resistive ballast is used, it is difficult to make the discharge lamp device compact and lightweight. In order to generate voltage, it is necessary to use a pulse transformer, a high-voltage, large-capacity capacitor, etc. in the lighting circuit, which has the drawback of being expensive. Particularly when a discharge lamp is used in a discharge lamp apparatus with a base socket, a major drawback is that the inductive ballast is heavy.

The present invention provides an inexpensive discharge lamp lighting device using a resistive ballast that does not have the above-mentioned drawbacks, and the present invention will be explained below based on the embodiments shown in FIGS. 1 to 4.

FIG. 1 is a circuit diagram showing an embodiment of a discharge lamp lighting device, in which a discharge lamp 2 is connected in series to a resistor ballast 1, and a semiconductor switch, such as a bidirectional two-terminal thyristor 3, is connected in parallel with the discharge lamp 2. do. Furthermore, a series circuit of an inductance element 4 and a nonlinear capacitor 5 is connected in parallel with the resistor ballast 1 and in series with the semiconductor switch 3.
Intermediate lead-out terminal 6 between and nonlinear capacitor 5
is provided and connected to the auxiliary electrode 7 along the tube wall of the discharge lamp 1.

Let me explain the lighting mechanism of this lighting device.
First, an alternating current voltage is applied to the power source as shown by the dotted line waveform in FIG. At the beginning of startup, the bidirectional two-terminal thyristor 3 is turned on at an appropriate phase of the positive half cycle of the power supply, and current flows through the resistive ballast 1 - the discharge lamp filament - the bidirectional two-terminal thyristor 3 - the discharge lamp filament. , the discharge lamp filament is heated. Next, as shown in Figure 3, the power supply voltage becomes zero (the current flowing through the thyristor becomes zero).
In phase, the bidirectional two-terminal thyristor 3 is turned off. On the other hand, the electric charge D of the nonlinear capacitor 5 and the voltage E between the terminals have a hysteresis characteristic as shown in FIG. A high voltage pulse is generated.

When this high-voltage pulse is applied to the auxiliary electrode 7, thermoelectrons are already emitted from the heated filament of the discharge lamp 2, and ions are generated near the tube wall. At this time, an alternating current voltage is applied between the filaments of the discharge lamp 2, and the ions travel through the ions near the wall of the discharge lamp tube, and discharge is started. When the discharge starts, the impedance of the discharge lamp 2 decreases, so
Bidirectional two-terminal thyristor 3 does not turn on,
Discharge continues.

FIG. 2 shows another embodiment, in which a bidirectional terminal thyristor 8 is connected in series with the nonlinear element 5, and the other configuration is the same as that in FIG.

In the case of Fig. 2, the AC voltage applied to the nonlinear capacitor 5 can be set near the peak value of the negative half cycle of the AC voltage, and the change in charging current di/dt can be made larger than in the case of Fig. 1. Therefore, the pulse voltage applied to the auxiliary electrode 7 can be increased.

Furthermore, after the discharge lamp 2 is lit, the impedance of the discharge lamp decreases, so the bidirectional two-terminal thyristor 8 can be turned off. 8 can be separated by a lighting circuit.

Here, the inductance element 4 does not carry enough current to heat the discharge lamp filament, so it can be a very small element, and the capacitance of the nonlinear capacitor 5 can be about 1000 to 3000 pF at most. , which can be made smaller and lighter as a lighting device. Further, the auxiliary electrode is not limited to the lead wire example described above, and its size and area may be designed as necessary, and other conductor wiring such as vapor deposition may be used.

As described above in detail, the present invention provides a discharge lamp lighting device that uses a resistance ballast, is small, lightweight, and inexpensive, and has excellent lighting startability, and is extremely practical.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the discharge lamp lighting device of the present invention, FIG. 2 is a circuit diagram of another embodiment of the discharge lamp lighting device of the present invention, and FIG. 3 is a semiconductor switching circuit used in the present invention. FIG. 4, which is an explanatory diagram of the operation of the element, shows a hysteresis characteristic diagram of the nonlinear capacitor used in the present invention. 1: resistance ballast, 2: discharge lamp, 3: semiconductor switch, 4: inductance element, 5: nonlinear capacitor, 7: auxiliary electrode.

Claims (1)

[Claims] 1. Connect a discharge lamp in series with a resistive ballast, connect a semiconductor switch in parallel with the discharge lamp, and connect a series circuit of an inductance element and a nonlinear capacitor in series with the semiconductor switch and in parallel with the resistive ballast. A conductor is connected between the inductance element and the nonlinear capacitor to form an auxiliary electrode along the discharge lamp, and a high voltage pulse is applied between the terminals of the auxiliary electrode and the discharge lamp. discharge lamp device.