JPH0950785A - Flat-panel fluorescent tube and lighting method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat-panel fluorescent tube, which can evenly emit light with small power consumption, by providing electrodes in both ends of long and narrow parallel discharge areas, which are obtained by dividing a discharge tube, and connecting one electrode to a power source through a piezoelectric transformer and an electronic switch means, and grounding the other electrode. SOLUTION: A discharge tube 10 is divided to plural long and narrow discharge areas in parallel with each other by partitioning plates 13, and terminals 21, 22 are provided in both ends of each discharge area, and the terminal 21 is grounded, and the terminal 22 is connected to a power source 40 through a piezoelectric transformer 22 and an electronic switch 30. The voltage raised by the transformer 22 is supplied to the discharge areas adjacent to each other in order. A flat-panel fluorescent display tube, which can evenly emit light at a small power consumption, is thereby obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat fluorescent tube suitable for use as a backlight of a liquid crystal display device or the like, and more particularly to a flat fluorescent tube having a plurality of parallel discharge paths. is there.

[0002]

2. Description of the Related Art Among liquid crystal display devices used for personal computers, liquid crystal televisions, viewfinders of video cameras, and the like, a transmissive liquid crystal display device requires a backlight to illuminate from the back surface of a liquid crystal panel.

This backlight needs to illuminate the entire surface of the liquid crystal panel, and is required to have a uniform brightness as a whole. In a general backlight, the irradiation light is guided to the back surface by a light guide plate from a thin fluorescent tube placed on the end face of the liquid crystal panel, and is reflected to the liquid crystal panel side by a reflection plate.

On the other hand, a flat-emission type backlight that emits light over the entire back surface of the liquid crystal panel has been considered. This is a technique in which a phosphor is applied to the inner surfaces of two glass plates, a rare gas is sealed therein, and discharge is caused by an electrode arranged in the space to emit light. Also, as one of the structures, there is a structure in which the discharge space is divided into U-shape and W-shape to form a long and narrow discharge path, and electrodes are arranged at both ends to discharge and emit light.

[0005]

In the light guide plate method, conversion efficiency is low due to loss and reflection at the introduction portion, and it is difficult to obtain uniform light emission. With a flat tube, the luminous efficiency is low and sufficient brightness cannot be obtained. In addition, the meandering structure has a large loss in the bent portion and consumes more power than a straight pipe. As a backlight for portable devices and the like, there is a great demand for low power consumption.

The present invention provides a flat fluorescent tube and a method of lighting the same, which enables substantial surface emission with low power consumption.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above problems by switching each straight tube type fluorescent tube with a switch and sequentially lighting the discharge in a flat type fluorescent tube in which straight tube type fluorescent tubes are arranged. To do.

That is, in a flat fluorescent tube in which a rare gas is enclosed and an electrode is arranged in a space composed of a transparent front plate having a phosphor coated on its inner surface, a back plate and a frame holding a space therebetween, The space is divided into a plurality of parallel elongated space parts by partition plates, electrodes are arranged at both ends of those parts, and one of the electrodes of each part is connected to an input power source via a piezoelectric transformer and electronic switching means. It is characterized by what has been done.

Further, a method for lighting a flat fluorescent tube in which a rare gas is enclosed in a space composed of a transparent front plate having a phosphor coated on its inner surface, a back plate and a frame holding a space therebetween and electrodes are arranged. In the above, the space is divided into a plurality of parallel elongated space portions by partition plates, electrodes are arranged at both ends of those portions, and one of the electrodes of each portion is input through a piezoelectric transformer and electronic switch means. It is characterized in that it is connected to a power source, and the piezoelectric transformer is sequentially driven by an electronic switching means to discharge and light.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of parallel spaces form discharge spaces, and when a switch is closed, an input voltage is boosted by a piezoelectric transformer to generate a discharge, which causes a phosphor to emit light. When a switch with a circuit configuration using transistors is switched at 100 Hz or higher to energize it to emit light, the flicker disappears to the human eye, and it is equivalent to a uniform light emission on the front surface.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing an embodiment of the present invention. The fluorescent tube 10 includes a glass or ceramic frame 11,
A discharge space is formed by 12 and the front plate and the back plate. The flat fluorescent tube according to the present invention has a partition plate 13 inside.
Are arranged in parallel and the discharge space is divided into a plurality of elongated spaces.

Electrodes 21 are provided at both ends of each elongated space.
22 is arranged, the electrode 21 is connected to the ground side, and the electrode 22 is connected to the input power source side. An electronic switch 30 is connected between the electrode 22 and the input power source 40 via a piezoelectric transformer 25. The electronic switch 30 can be formed by a normal switch circuit that sequentially switches a plurality of transistors.

A phosphor is applied to the inner wall surfaces of the frame body 11, the partition plate 13, the front plate and the back plate. Further, a rare gas such as argon is sealed in the discharge space. Also,
Although not shown, a mercury getter may be placed in the discharge space together with the electrodes.

The piezoelectric transformer 25 has its input side, that is, the low-voltage side, connected to the electronic switch means 30, and its output side, that is, the high-voltage side, connected to the electrode 22. Since arranging the electronic switch means on the high voltage side causes problems such as withstand voltage, it is desirable to arrange the electronic switch means on the low voltage side.

When one of the electronic switches 30 is turned on and off, the input voltage is boosted by the piezoelectric transformer 25, a discharge is generated in the connected discharge space, and the phosphor emits light. If the adjacent discharge spaces are sequentially made to emit light by switching the switches, and the discharge spaces are repeatedly made to circulate, then it becomes almost the same state where the whole is emitting light uniformly. To do this, switch the switch at a frequency of 100Hz or higher. The upper limit is limited by the rising characteristics of the discharge part, but it is possible up to about 500Hz.

[0017]

According to the present invention, since one straight tube is sequentially turned on, the power consumption for one straight tube can be sufficient, and the flat fluorescent tube can be reduced in power consumption.

It is easy to obtain uniformity of light emission, and since the switch is connected to the low voltage side, the circuit configuration of the switch circuit can be simplified.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention.

[Explanation of symbols]

 11, 12: Frame 13: Partition plates 21, 22: Electrode 25: Piezoelectric transformer 30: Electronic switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuyoshi Takano 828 Hinohara, Tamagawa, Hamahara, Hiki-gun, Saitama Prefecture Toko Co., Ltd. Tamagawa factory

Claims (5)

[Claims] 1. A flat fluorescent tube in which a rare gas is sealed in a space formed of a transparent front plate having a fluorescent material coated on its inner surface, a rear plate and a frame holding a space therebetween, and electrodes are arranged, The space is divided into a plurality of parallel elongated space parts by partition plates, electrodes are arranged at both ends of those parts, and one of the electrodes of each part is connected to an input power source via a piezoelectric transformer and electronic switching means. A flat fluorescent tube characterized by the above. 2. A method of lighting a flat fluorescent tube in which a rare gas is enclosed in a space composed of a transparent front plate having a phosphor coated on its inner surface, a back plate and a frame holding a space between them and electrodes are arranged. In the above, the space is divided into a plurality of parallel elongated space portions by partition plates, electrodes are arranged at both ends of those portions, and one of the electrodes of each portion is input through a piezoelectric transformer and electronic switch means. A method for lighting a flat fluorescent tube, comprising connecting to a power source and sequentially driving a piezoelectric transformer by an electronic switching means to light a discharge. 3. A flat fluorescent tube in which a rare gas is enclosed in a space composed of a transparent front plate having a phosphor coated on its inner surface, a rear plate and a frame holding a space between them, and electrodes are arranged in the flat fluorescent tube. The space is divided into a plurality of parallel elongated space parts by partition plates, electrodes are arranged at both ends of those parts, and one of the electrodes of each part is connected to the output side of the piezoelectric transformer and the input side of the piezoelectric transformer is connected. A flat fluorescent tube characterized in that each of them is connected to an input power source via an electronic switch means. 4. A method of lighting a flat fluorescent tube in which a rare gas is enclosed in a space formed by a transparent front plate having a phosphor coated on its inner surface, a back plate, and a frame holding a space between them, and electrodes are arranged. In the above, the space is divided into a plurality of parallel elongated space portions by partition plates, electrodes are arranged at both ends of those portions, and one of the electrodes of each portion is connected to the output side of the piezoelectric transformer. A method for lighting a flat fluorescent tube, characterized in that the input side of each is connected to an input power source through an electronic switch means, and the piezoelectric transformer is sequentially driven by the electronic switch means to perform discharge lighting. 5. The flat fluorescent tube according to claim 1, wherein the mercury getter is housed in the elongated space together with the electrode.