JPH06325882A - Fluorescent lamp lighting device - Google Patents

Abstract

PURPOSE:To provide an inverter for fluorescent lamp which prevents drop of the light flux of fluorescent lamp under its low temp. operation. CONSTITUTION:A resonance circuit is composed of an inductance, capacitor 5, and fluorescent lamp 4, and the lamp is lighted up by an inverter which includes an oscillator circuit to do oscillating with a switching element. A fluorescent lamp lighting device concerned is provided with filament windings 21, 22 which heat the lamp electrodes 41, 42 while the lamp is being lighted.

Description

The present invention causes a resonance circuit including a fluorescent lamp to perform a boosting operation, and a heating current is constantly supplied to the electrodes of the fluorescent lamp during lighting of the fluorescent lamp to reduce the temperature of the fluorescent lamp at low temperature. The present invention relates to a fluorescent lamp lighting device that prevents a decrease in luminous flux. Generally, fluorescent lamps are affected by ambient temperature. When the ambient temperature decreases, mercury condenses and the mercury vapor pressure decreases, the amount of mercury vapor present decreases, and 2537Å radiation cannot be emitted in large amounts, and the luminous flux decreases. FIG. 1 is a circuit diagram of a fluorescent lamp lighting device using an inverter that lights a resonant circuit, which is generally used in the past, including an inductance, a capacitor, and electrodes of the fluorescent lamp at a high frequency. When a power source is applied, a high frequency voltage is generated in the oscillation transformer 2 by the oscillator circuit 1 of the inverter, and this voltage is used as a power source for the current limiting choke 3, the resonance circuit of the electrodes 41 and 42 of the fluorescent lamp 4 and the resonance capacitor 5. As a result, a sufficient preheating current and a secondary voltage are applied to the fluorescent lamp 4 to turn it on. When the fluorescent lamp 4 is turned on, the tube voltage of the fluorescent lamp 4 is applied to the resonance capacitor 5, so that the voltage applied to the resonance capacitor 5 becomes low, and the electrodes 41 and 42 receive a slight heating current. Not flowing. As a result, the fluorescent lamp 4 is kept at a low temperature (0 ° C to -20 ° C).
Since the temperature near the electrodes does not rise when turned on at (° C),
Mercury in the vicinity does not evaporate and a sufficient luminous flux cannot be obtained. The present invention is intended to improve the above-mentioned drawbacks, and proposes a method of increasing the luminous flux at low temperature by adopting a one-transistor resonance circuit in which the cataphoresis phenomenon of a fluorescent lamp does not easily occur at low temperature. FIG. 2 shows an embodiment of the present invention in which the filament heating windings 21 and 22 are wound around the oscillation transformer 2 shown in FIG. When the fluorescent lamp 4 is turned on, the electrodes 41 and 42 of the fluorescent lamp 4 induced by the filament heating windings 21 and 22 are heated, and as a result, mercury in the vicinity of the electrodes is sufficiently vaporized even in a low temperature region, so that the luminous flux is Greatly improved compared to conventional products. Table 1 shows a comparison of illuminance at -20 ° C. when the FLR25 lamp is lit at a constant current in the circuits of FIGS. 1 and 2. The illuminance is calculated with the conventional product of FIG. 1 as 100.

FIG. 3 shows another embodiment of the present invention in which the filament heating windings 31 and 32 of the fluorescent lamp 4 are wound on the current limiting choke 3 and have the same effect as in FIG. As described above, by providing the filament heating winding of the fluorescent lamp to the inverter that uses the resonance circuit consisting of the inductance, the capacitor, and the electrode of the fluorescent lamp, a sufficient luminous flux can be generated even if the fluorescent lamp is lit at a low temperature. There is an effect to obtain.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a conventional fluorescent lamp lighting device, and FIGS. 2 and 3 are circuit diagrams showing an embodiment of the present invention.

Claims (1)

[Claims] An inverter including an oscillating circuit that oscillates with a switching element in a resonance circuit composed of an inductance, a capacitor, and a fluorescent lamp, and a filament for lighting the fluorescent lamp and heating at least the electrode of the fluorescent lamp while the fluorescent lamp is lit. Fluorescent lamp lighting device with heating winding.