JPH07240292A - Discharge lamp lighting device and lighting system - Google Patents

Abstract

PURPOSE:To detect the final phase of the service life of a discharge lamp in a simple structure, by detecting the quantity of electricity according to the lamp voltage of a discharge lamp in only the power feeding direction of a DC current, and controlling an electron stabilizing means so as to carry out a protective operation. CONSTITUTION:A discharge lamp 1 is lighted by a high-frequency output in which DC currents are superposed by a DC superposing means B. As a result, a filament to be at the anode side to a DC component is liable to receive a damage by the impact of electrons compared to the other side filament, and is deteriorated rapidly. And, at the final phase of the service life, a half-wave discharge is generated from the filament at the anode side to the other side, and the lamp voltage in this direction is raised. Such a phenomenon is detected by a detecting means C, and according to this output, a control circuit 23 converts the switching cycle of a transistor 7, so as to throttle or stop the high-frequency output. Since a filament liable to be deteriorated is specified, a detecting circuit of the quaitity of electricity can be simplified.

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 for safely operating a discharge lamp such as a low-pressure mercury vapor discharge lamp and a lighting device using the same.

[0002]

2. Description of the Related Art Conventionally, as a discharge lamp lighting device provided with a means for detecting a half-wave discharge at the end of the life of the discharge lamp, there is known one disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 2-162696. As shown in FIG. 3, this is a charging circuit 36 for charging a capacitor Co in a discharge lamp lighting device for lighting a discharge lamp at a high frequency using an inverter.
And a discharge circuit 37 for discharging the charged electric charge of the capacitor Co, and a lamp current for each half wave flowing through the discharge lamp 1 through the current transformer CT or a lamp voltage generated at both ends of the discharge lamp is taken out from them. The lighting state of the discharge lamp 1 is determined from the detection circuit 35 that detects the lighting state of the discharge lamp 1 and controls the operations of the charging circuit 36 and the discharge circuit 37 according to the lighting state of the discharge lamp 1 and the voltage waveform across the capacitor Co. Then, the output control circuit 34 for controlling the operation of the inverter I is provided in an appropriate operating state according to the lighting state of the discharge lamp l. That is, when the discharge lamp 1 begins to deteriorate and half-wave discharge indicated by an arrow in the figure occurs, the current in one direction becomes large, and the charging circuit 36 and the discharging circuit 37 have different charging and discharging time constants of the capacitor Co. Therefore, if this is detected, the end of life of the discharge lamp 1 can be determined.

[0003]

However, according to this conventional discharge lamp lighting device, it is unclear which one of the pair of filaments of the discharge lamp is attached to the emitter and the half wave is deteriorated. Since the discharge direction of is not specified, the voltage or current in both directions of the discharge direction must be detected. Therefore, the detection circuit for detecting the discharge at the end of the life of the discharge lamp becomes complicated, and
The reliability of the detection was poor. Then, this invention solves the fault of a prior art, and an object of this invention is to provide the discharge lamp lighting device and lighting device which can detect the end of life of a discharge lamp with a simple structure.

[0004]

In order to achieve the above object, a discharge lamp lighting device according to a first aspect of the present invention provides an electronic stabilizing means for generating a high frequency output and having a discharge stabilizing function, and input power to the electronic stabilizing means. Power supply, a DC superimposing means for superimposing a DC current on the high frequency output generated by the electronic stabilizing means, a discharge lamp lit by the high frequency output on which the DC current is superimposed, and a discharge lamp only in the direction of the DC current flow. The detection means for detecting the amount of electricity according to the lamp voltage, and the control means for controlling the electronic stabilizing means to perform the protection operation according to the output of the detection means.

An illumination device according to a second aspect of the invention is characterized in that the discharge lamp lighting device according to the first aspect is built into the main body of the fixture to light the discharge lamp. Here, the illuminating device includes not only a general illuminating device that illuminates an object or a space, but also an advertising lamp or an illuminating device such as a backlight for a display device that illuminates light from the back surface of a liquid crystal display screen. Also includes.

[0006]

In the present invention, since the discharge lamp is lit by the high frequency output on which the direct current is superposed, the deterioration of the anode side filament progresses earlier than the deterioration of the cathode side filament in the direction of direct current flow. . Therefore, the end of life of the discharge lamp can be detected with a simple configuration by detecting only the amount of electricity according to the lamp voltage at the time of discharge in the direction in which electrons flow from the anode side filament to the other filament in the direction of direct current flow. .

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration diagram of a discharge lamp lighting device according to an embodiment of the present invention, and FIG. 2 shows an embodiment of a lighting device of the present invention. That is, as shown in FIG. 1, with respect to the discharge lamp 1, the alternating current from the alternating current power supply 2 is rectified by the diode bridge 3, and the rectified output is smoothed by the smoothing capacitor 4 to be the direct current power supply. It is supplied as a high frequency wave of, for example, 45 KHz by the transistor inverter that constitutes it. A resonance capacitor 6 is connected in parallel to the primary winding of the inverter transformer 5, and a transistor 7 serving as a switching element is connected to the capacitor 6.
The collector of is connected.

The secondary winding side of the transformer 5 is connected to the primary winding of a current transformer 9 via a DC current blocking capacitor 8 and is further connected to the filament of the discharge lamp 1. The other filament of the discharge lamp 1 is the transformer 5 2
It is connected to the secondary winding. A starting capacitor 10 is connected in parallel to the discharge lamp 1. A secondary winding of a current transformer 9 for returning the lamp current of the discharge lamp 1 is connected to the base of the transistor 7, and an output limiting capacitor 1 is provided between this winding and the emitter of the transistor 7.
1 and a circuit in which a capacitor 12 and a FET 13 are connected in series are connected in parallel with the circuit 1.

A DC superimposing means B is connected in parallel between the secondary winding of the inverter transformer 5 and the discharge lamp 1. That is, the DC superimposing means B formed of a series body of a resistor 14 serving as a current limiting element for a DC current, a high frequency blocking inductor 15 and a DC power supply 16 is connected in parallel to the discharge lamp 1, and an inverter transformer. 2 of 5
It is configured to superimpose a DC component on the high frequency output to the next side. In the above circuit, transformer 5
When a voltage is generated, the secondary winding of the transformer 5 and the capacitor 6 resonate with each other, and a resonance current flows through the current transformer 9.
At this time, the transistor 7 is in the ON state, but continues to be in the ON state by receiving the resonance current. The current in the secondary winding of the current transformer 9 acts to charge the capacitor 11. When the capacitor 11 is filled with electric charge, the charging current does not flow and the current transformer 9 is magnetically saturated and the transistor 7 is turned off. . At this time, the transformer 5 is the capacitor 5,
Resonating state with 10 respectively, the current transformer 9,
Current flows in the opposite direction to the above. This causes the transistor 7 to be reverse biased. During this time, the electric charge of the capacitor 11 is discharged through a discharge path (not shown), the transistor 7 is turned on again by the next reversal of resonance, and the same operation as described above is repeated, so that the filament of the discharge lamp 1 is sufficiently discharged. It is preheated and the discharge lamp is turned on.

In the discharge lamp lighting device according to this embodiment, the detecting means C for detecting the quantity of electricity according to the lamp voltage of the discharge lamp 1 is connected in parallel to the filament preheating capacitor 10. That is, the voltage across the discharge lamp 1 is divided by the resistors 17 and 18, half-wave rectified and smoothed by the diode 19 and the capacitor 20, and input to one input terminal (plus) of the OP amplifier 21. The reference voltage is the Zener diode 22 that biases the reference voltage.
Is inputted to the other terminal of the OP amplifier 21 via the, and the reference voltage is compared with the voltage obtained by the voltage dividing resistor, and a voltage corresponding to the difference is output to the control circuit 23 which is the control means. As a result, only the forward voltage half-wave rectified with respect to the voltage in the discharge in the direction in which the electrons go from the filament on the anode side (the lower filament in the figure) to the other filament with respect to the superimposed DC current. , To the OP amplifier 21.

In the above circuit, since the discharge lamp 1 is turned on by the high frequency output in which the direct current is superimposed by the direct current superimposing means B, the filament on the anode side with respect to the direct current component becomes the other filament. In comparison, it will deteriorate earlier. That is, the filament on the anode side with respect to the direct current is more likely to be damaged by the impact of electrons than the other filament, and is deteriorated earlier by that amount. Therefore, when the discharge lamp 1 reaches the end of its life, a half-wave discharge occurs from the filament on the anode side toward the other with respect to the direct current, and in this direction, in other words, the direct current is supplied by the direct current superimposing means B. The lamp voltage in the direction increases, and the detecting means C detects a voltage corresponding to the voltage. Then, the control circuit 23 changes the switching cycle of the transistor 7 in accordance with the output of the detecting means C to reduce or stop the high frequency output. Therefore, according to such a device, it is possible to identify the filament that is easily deteriorated from the pair of filaments of the discharge lamp. Therefore, it suffices to detect the quantity of electricity according to the lamp voltage in only one of the discharge directions. It will be easy.

The discharge lamp lighting device having the above-described structure has an electronically-stabilized device in a fixture body D in which a reflecting surface is formed on the lower surface and discharge lamp sockets are provided at both ends of the lower surface as shown in FIG. The lighting device is configured by accommodating the conversion unit, the DC superimposition unit, the detection unit and the control unit, and mounting the discharge lamp 1 in the socket.

In the above embodiment, the DC current blocking capacitor 8 is formed of, for example, a parallel body of two capacitors, and these two capacitors are switched by a switch or the like, so that variations in the starting voltage of the discharge lamp can be prevented. Compensation may be performed over a wide range.

In the above embodiments, the one-stone type inverter is used as the electronic stabilizing means, but the present invention is not limited to this, and may be, for example, a half bridge type, a push pull type, or the like. It can also be applied to a full-bridge type inverter. Furthermore, as the quantity of electricity according to the lamp voltage, in the above-mentioned embodiment, a voltage obtained by dividing the voltage across the discharge lamp by a resistor is detected, but the lamp current is detected by detecting the lamp current, for example. It is also possible to detect the amount of electricity according to the voltage.

[0015]

As described above, according to the present invention, since the discharge lamp is lit by the high frequency output on which the direct current is superimposed, the deterioration of the cathode side filament in the direction of direct current flow causes deterioration of the anode side filament. Degradation will proceed first. Therefore, the end of life of the discharge lamp can be detected with a simple configuration by detecting only the amount of electricity corresponding to the lamp voltage during discharge in the direction from the anode side filament to the other filament in the direction of direct current flow.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a discharge lamp lighting device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a lighting device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional discharge lamp lighting device.

[Explanation of symbols]

1 ... Discharge lamp 2 ... AC power supply 3 ... Diode bridge 4, 5, 6, 8, 10, 11, 12, 20 ... Capacitor 5 ... Transformer 7 ... Transistor 9 ... Current transformer 23 ... Control circuit (control means) A ... Electronic stabilizing means B ... DC superimposing means C ... Detecting means D ... Instrument body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoteru Kosa 4-3-1, Higashishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Lighting & Technology Corporation

Claims (2)

[Claims] 1. An electronic stabilizing means for generating a high frequency output and having a discharge stabilizing function, a power supply for supplying an input power to the electronic stabilizing means, and a direct current superposed on a high frequency output generated by the electronic stabilizing means. DC superimposing means, a discharge lamp that is lit by a high-frequency output on which a DC current is superimposed, a detecting means that detects the amount of electricity according to the lamp voltage of the discharge lamp only in the energizing direction of the direct current, and an output of the detecting means. A discharge lamp lighting device comprising: a control unit that controls an electronic stabilizing unit to perform a protective operation in accordance with the control unit. 2. A lighting device, characterized in that the discharge lamp lighting device according to claim 1 is built in a fixture body to light the discharge lamp.