Apparatus for lighting fluorescent lamp

Abstract

A fluorescent lamp lighting apparatus in accordance with the present invention has first switching means (M1) driven by a high-voltage-side pulse signal input from a drive-signal generation circuit and second switching means (M2) driven by a low-voltage-side pulse signal input from the drive-signal generation circuit, wherein the first switching means (M1) is connected in series with the second switching means (M2), and a first capacity (C5) and an inductance element (L1) and the above-mentioned second switching means (M2) are provided between the high-voltage-side terminals of a pair of filament electrodes of a light-emitting tube (4), whereby a constant luminous flux can be maintained immediately after lighting.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to an apparatus for lighting fluorescent lamp, particularly to a bulb-type fluorescent lamp, that is, a fluorescent lamp having a shape of electric bulb.[0002]In recent years, in view of energy conservation and the like, bulb-type fluorescent lamps have been used instead of incandescent lamps. In a conventional bulb-type fluorescent lamp, a light-emitting tube, a starter and a stabilizer are integrated and accommodated in the screw base portion thereof, making the base portion large and heavy.[0003]FIG. 47 is a circuit diagram of a conventional bulb-type fluorescent lamp. The circuit configuration of the bulb-type fluorescent lamp will be described below referring to FIG. 47.[0004]An AC power source 101 is connected to the AC input terminals of a full-wave rectifier 104 via a filter circuit comprising an inductor 103 and a capacitor 102. A smoothing capacitor 105 is connected across the DC output terminals of the full-wa...

AI Technical Summary

Benefits of technology

[0014]In order to solve the above-mentioned problems, the present invention provides an apparatus for lighting fluorescent lamp, that is a fluorescent lamp lighting apparatus, configured to sufficiently provide a preheating time at the time of lighting and capable of carrying out control at a level not applying stress to the filaments of the light-emitting tube thereof. In addition, the present invention is intended to provide a fluorescent lamp lighting apparatus having a smaller mounting area by significantly reducing the number of components by using a one-chip monolithic IC accommodating an oscillator, and capable of maintaining a constant luminous flux immediately after lighting.

[0019]In accordance with the present invention configured as described above, the power source circuit portion has the DC-voltage generation circuit, the drive-signal generation circuit and the drive control circuit, and the need for a transformer coil is eliminated; therefore, the mounting area of the power source circuit portion is decreased significantly, and the number of components is reduced.

[0024]In the present invention configured as described above, the power source circuit portion has the DC-voltage generation circuit, the drive-signal generation circuit and the drive control circuit, and the need for a transformer coil is eliminated by providing a semiconductor integrated circuit; therefore, the mounting area of the power source circuit portion is decreased significantly, and the number of components is reduced.

[0031]In accordance with the present invention configured as described above, a signal having a frequency different from the resonance frequency of the resonance circuit network can be generated at the time of power on, whereby a desired voltage can be applied to the filament electrodes without abruptly applying a high voltage caused by resonance. Furthermore, the frequency to be supplied to the resonance circuit network is changed with the passage of time and passed through the resonance frequency band, whereby the light-emitting tube can be lit securely in the vicinity of the resonance frequency. Moreover, the signal having the phase corresponding to the signal of the signal detection terminal is supplied to the resonance circuit network after the predetermined time has passed from power on, thereby to form a closed loop for driving the resonance circuit network, whereby the resonance state can be maintained, and the light emission of the light-emitting tube can be continued. In this way, abrupt stress is not applied to the filament electrodes and the light-emitting tube, whereby the service life of the light-emitting tube can be extended; in addition, the temperature of the light-emitting tube is raised and light is emitted, whereby the change in the luminous flux immediately after light emission can be suppressed.

[0040]In accordance with the present invention configured as described above, the power source circuit portion has the DC-voltage generation circuit, the drive-signal generation circuit and the drive control circuit, and the need for a transformer coil is eliminated; therefore, the mounting area of the power source circuit portion is decreased significantly, and the number of components is reduced.

[0041]In accordance with the present invention configured as described above, a signal having a frequency different from the resonance frequency of the resonance circuit network can be generated at the time of power on, whereby a desired voltage can be applied to the filament electrodes without abruptly applying a high voltage caused by resonance. Furthermore, the frequency to be supplied to the resonance circuit network is changed with the passage of time and passed through the resonance frequency band, whereby the light-emitting tube can be lit securely in the vicinity of the resonance frequency. Moreover, the signal having the phase corresponding to the signal of the signal detection terminal is supplied to the resonance circuit network after the predetermined time has passed from power on, thereby to form a closed loop for driving the resonance circuit network, whereby the resonance state can be maintained, and the light emission of the light-emitting tube can be continued. In the fluorescent lamp lighting apparatus of the present invention, the resonance connection portion of the first and second switching means can be driven by the voltage across the output terminals of the DC-voltage generation circuit, whereby it is possible to generate a voltage required to drive the filament electrodes. In this way, abrupt stress is not applied to the filament electrodes and the light-emitting tube, whereby the service life of the light-emitting tube can be extended; in addition, the temperature of the light-emitting tube is raised and light is emitted, whereby the change in the luminous flux immediately after light emission can be suppressed.

Problems solved by technology

Therefore, stress is applied to the filaments of the light-emitting tube, thereby causing a problem of shortening the service life of the light-emitting tube.

Furthermore, in the conventional bulb-type fluorescent lamp, the preheating time for the filaments cannot be taken sufficiently, thereby causing a problem of making the luminous flux small because the temperature of the external tube is low immediately after lighting, and making the luminous flux larger as the temperature of the external tube rises.

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