JPH0118554B2 - - 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.

In general, discharge lamps 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. In order to initiate the discharge, it is necessary to apply a 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 disadvantage of being expensive. Particularly when a discharge lamp is used in a discharge lamp lighting device with a base socket, the inductive ballast is heavy and becomes a major drawback.

The present invention provides an inexpensive discharge lamp lighting device using a resistive ballast that does not have the above-mentioned drawbacks, and will be described below based on the embodiments shown in FIGS. 1 to 5.

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

To explain the lighting mechanism of this discharge lamp 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 FIG. 4, the bidirectional two-terminal thyristor 3 is turned off at a phase in which the power supply voltage becomes zero (the current flowing through the thyristor becomes zero). On the other hand, the charge D of the nonlinear capacitor 5
The terminal voltage E has a hysteresis characteristic as shown in FIG. 5, and the charging current rapidly decreases near the peak value of the power supply voltage, and a high voltage pulse equivalent to Ldi/dt is generated in the inductance element 4.

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 discharge begins through the ions near the wall of the discharge lamp tube. When the discharge starts, the impedance of the discharge lamp 2 decreases, so the bidirectional two-terminal thyristor 3 is not turned on and the discharge continues.

FIG. 2 shows another embodiment of FIG. 1, in which a bidirectional two-terminal thyristor 8 is connected in series with the nonlinear capacitor 5
The other configurations are the same as in FIG. 1. 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. The pulse voltage given to the auxiliary electrode 7 can be increased.

Further, FIG. 3 shows another embodiment, and the lighting mechanism is the same as that in FIG. 1.

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 nonlinear capacitor 5 has a small capacitance of about 1000 to 3000 pF at most. Since the lighting device can be made smaller and lighter, the lighting device can be made smaller and lighter.

Further, the auxiliary electrode is not limited to the lead wire example described above, but its size and area can be designed as required, and various conductor wiring such as vapor deposition is possible.

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, FIGS. 2 and 3 are circuit diagrams of other embodiments of the discharge lamp lighting device of the present invention, and FIG. 4 is a circuit diagram of another embodiment of the discharge lamp lighting device of the present invention. FIG. 5 shows a hysteresis characteristic diagram of a 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 resistor ballast, connect a semiconductor switch in parallel with the discharge lamp, connect a series circuit of an inductance element and a nonlinear capacitor in parallel with the semiconductor switch, and connect the inductance element and a nonlinear capacitor in parallel. A discharge lamp lighting device characterized in that an auxiliary electrode is formed along the discharge lamp by a conductor led out from between the nonlinear capacitor and a high voltage pulse is applied to the auxiliary electrode.