JPS61118996A - Heat cathode fluorescent lamp lighting apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lighting device for a compact hot cathode fluorescent lamp, which has recently been attracting attention as a light source for bank lights such as liquid crystal display devices.

[Conventional technology]

Conventionally, in general hot cathode fluorescent lamps, there have been automatic filament energization methods using a glow start switch, and artificial filament energization switches with multi-stage power switches.

[Problem that the invention seeks to solve]

However, the compact hot cathode fluorescent lamps that have been attracting attention recently need to be able to be sufficiently powered by dry batteries, etc., so a glow start that requires a large amount of power at startup is not suitable, and a method where a person turns the filament on and off using a switch is not suitable. There are problems such as the filament being cut.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hot cathode fluorescent lamp lighting device that reduces power consumption when starting up a compact hot cathode fluorescent lamp, and that uses low power during normal conditions, that is, arc discharge.

[Means for solving problems]

In hot cathode fluorescent lamps, the filament is usually heated by energizing it. However, if the discharge shifts from glow discharge to arc discharge, a sustained arc discharge will be formed even if the filament is turned off, so there will be no problem with brightness or the like. In particular, in ultra-compact fluorescent lamps, which have been attracting attention in recent years as backlights for small liquid crystal display devices, etc., the proportion of power applied to the filament is large compared to the power consumption of the fluorescent lamp itself, increasing the overall power consumption. If a dry battery is used as a power source for a portable device, the life of the battery will be shortened, and as mentioned above, it is essential to turn off the current to the filament when transitioning to arc discharge. In addition, when starting a fluorescent lamp, the power applied to the fluorescent lamp itself and the power applied to the filament are combined, so a power source that can draw a large current is required.If a battery is used as a power source, the terminal voltage of the battery decreases and the fluorescent lamp drive circuit It may not work properly.

Therefore, by preheating the filament by energizing only the filament for a certain period of time after turning on the power, and then applying high voltage to the fluorescent lamp itself, the large current at startup is suppressed and the glow discharge time is reduced to zero. Or, it was configured to be a short time.

Embodiment FIG. 1 is a block diagram showing an embodiment of the present invention.

A battery 1 serves as a power source, and is connected to a timer circuit 2 and a high voltage drive circuit B via a switch 4. Reference numeral 2 denotes a timer circuit which outputs an H level control signal S from the control output terminal C for a certain period of time after the switch 4 is closed. 6 is a high voltage drive circuit which outputs a high voltage AC signal P to a high voltage output terminal H only when the control signal S is at L level. 5 is a hot cathode fluorescent lamp, which includes a filament 5a and a cold cathode terminal 5.
One of the filaments of the high-voltage output terminal H1 is connected to the (-) terminal of the battery, and the other of the high-voltage output terminals H1 is connected to the control output terminal C of the cold cathode terminal 5b.

Now, when the switch 4 is closed, power is supplied to the timer circuit 2, and the control signal S of the timer circuit 2 becomes H level, applying voltage to the filament 5a of the fluorescent lamp 5 and heating it. At that time, the high voltage drive circuit 3 does not operate and the high voltage AC signal P
Fluorescent lights are not turned on to maintain the L level. Eventually, after a certain period of time has passed, the control signal S of the timer circuit 20 goes to L level, and the potential difference between both ends of the filament 5a of the fluorescent lamp 5 is reduced to 0.
then stop heating. At that time, the high-voltage drive circuit 6 starts operating, and a high-voltage alternating signal is output to the high-voltage AC signal S to immediately light the fluorescent lamp in an arc discharge state without glow discharge.

Furthermore, by measuring the ambient temperature using a temperature sensor and automatically controlling the timer circuit to set a longer time when the temperature is low, it is possible to create more accurate lighting conditions.

〔Effect of the invention〕

As is clear from the following explanation, according to the present invention, when lighting a hot cathode fluorescent lamp, the filament is heated in advance and then high voltage is applied to both ends of the hot cathode fluorescent lamp, thereby achieving the following effects. be.

(1) The power of the fluorescent lamp itself is maximized by the power used by the filament, whichever is greater, and the power supply capacity can be reduced, making it possible to use batteries as a power source and downsizing. It becomes possible.

(2) Since the glow discharge state is eliminated or becomes short-lived, the life of the fluorescent lamp itself can be extended.

[Brief explanation of drawings]

FIG. 1 is a clock diagram of an embodiment of the present invention. 1...Battery, 2... Timer circuit, 6...High voltage drive circuit, 4...Switch, 5...Fluorescent light, 5a...Filament, 5b... Cold cathode terminal.

Claims (1)

[Claims] It has a hot cathode fluorescent lamp, a high voltage drive circuit for applying high voltage to the hot cathode fluorescent lamp, and a timer circuit, and the filament of the hot cathode fluorescent lamp is turned off from the time the power is turned on until the set time of the timer circuit. A hot cathode fluorescent lamp lighting device, characterized in that the hot cathode fluorescent lamp is heated, and after a set time, the high voltage drive circuit is operated to apply high voltage to the hot cathode fluorescent lamp.