JPH03184252A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To provide a low pressure discharge lamp, whose tube end structure is made simple and which is equipped with a high efficiency and long lifetime, by embodying a cold cathode discharging electrode in the form of a tungsten cylinder, and allowing the internal circumferential surface of this cylinder to serve as an at-discharge hollow electrode. CONSTITUTION:A cylindrical electrode 5 made of tungsten is used as structure of two-end electrode. The internal circumferential surface of this cylindrical electrode 5 works so as to emit a hollow drop, and the outside dia., wall thickness, and length of the electrode 5 can be adjusted as desired, so that a design with protection of lamp lifetime can be made easily by increasing the electrode with enlarging lamp current. This enables achievement of a fluorescent lamp equipped with a high lamp efficiency and long lifetime.

Description

[Detailed description of the invention] [Industrial application field] The present invention is a backlight 1 for liquid crystal and facsimile.

This article relates to small diameter fluorescent lamps used in copy machines and the like.

[Conventional technology]

Regarding hot cathode discharge lamps and cold cathode discharge lamps, please refer to the Illumination Handbook (May 1978) edited by the Illuminating Engineering Institute of Japan.

Ohmsha), pages 759 to 760. Further, hot cathode type fluorescent lamps are described on page 160 of the same document. Regarding the structure of the hot cathode, please refer to the Lighting Handbook (1936) edited by the Illuminating Engineering Society of Japan.
It is described on page 121 of Ohmsha, November 2013.

[Problem to be solved by the invention]

In the above-mentioned conventional hot cathode type low pressure discharge lamp, two lead wires connected to both ends of one electrode are required in order to heat the electrode by energizing it.

The disadvantage is that the structure of the end of the discharge tube becomes complicated.

In particular, the above drawbacks were fatal when the dimensions of the discharge vessel were small. In addition, cold cathode type low pressure discharge lamps have lead wires that are made of industrial water for each electrode, but they have the disadvantage that the cathode drop voltage is high and therefore the efficiency is low. moreover,
When the discharge current is 10 mA or more, the service life is short.

An object of the present invention is to provide a low-pressure discharge lamp with a simple tube end structure, high efficiency, and long life.

[Means to solve the problem]

In order to achieve the above object, the present invention uses a tungsten cylinder as a cold cathode discharge electrode.

By using a hollow electrode on the inner diameter of the cylinder during discharge, we aim to extend the lifespan at high currents.

Furthermore, by forming a hollow in the hole provided on the side surface of the cylinder, the cathode drop voltage can be reduced.

Furthermore, by filling the inside of the cylinder with oxide containing barium oxide, the work function of the electrode is further reduced, and the cathode drop voltage is further reduced.

[Effect]

The inner diameter part of the tungsten cylindrical electrode of the electrode operates to produce a hollow drop, and the hole diameter of the hole in the cylindrical side part is set to about 0.1 to 0.5 mm to optimize the hollow effect. The cathode drop voltage can be reduced by about 10% compared to when using a simple cylinder.

Furthermore, in the case of filling the inside of the cylinder with oxide containing barium oxide, compared to the case of using a simple cylindrical electrode, the
Since the cathode drop voltage can be reduced by about 0 to 40%, a fluorescent lamp suitable for a cold cathode through which a large current flows can be obtained.

〔Example〕

The present invention will be explained below with reference to the drawings.

FIG. 1 shows the overall structure of a cold cathode fluorescent lamp according to an embodiment of the present invention, and FIGS. 2, 3, and 4 show details of the electrode portion.

Both ends of the glass tube 1 are sealed, and a phosphor 2 is placed on the inner wall of the glass tube.
is applied, and mercury 3 and Ar gas 4 are sealed inside. Furthermore, electrodes 5 of the present invention are welded to lead wires 6 at both ends.

The tungsten cylindrical electrode 5 shown in FIG. 2 has an outer diameter.

It has the advantage of being able to freely adjust the wall thickness and length.
As the lamp current increases, the electrodes can be easily designed to be larger so as not to impair lamp life. By the way, the relationship between lamp current and electrode surface area is 5 to 25 mm.
”/1 mA is suitable.

The electrode 5 shown in FIG. 3 is a cylinder with numerous holes provided on the side surface. By discharging from the hole, a hollow effect occurs, and when the hole diameter is about 0.2 to 1-1, it was confirmed that the cathode drop voltage due to the hollow effect was about 10% lower than when it was cylindrical. did. Here, there is no particular difference between the number of holes and the cathode drop voltage, but by making the number of holes infinite and varying the hole diameter, it is possible to select the optimum hole diameter and discharge.

FIG. 4 shows the electrode of FIG. 2 further filled with oxide containing barium oxide. By reducing the work relationship of the electrodes in this way, the cathode drop voltage can be reduced to a second level.
It can be made about 30-40% smaller than the one shown.

In addition, the oxide used in this example was an activated carbonate of a generally used ternary system of barium, calcium, and strontium, but there was little change in performance depending on the composition. No particular difference in performance was observed whether high-frequency heating was performed during the evacuation process after sealing the tube or if it was activated before sealing.

〔Effect of the invention〕

According to the present invention, it is possible to easily change the electrode surface area depending on the magnitude of the lamp current in a cold cathode fluorescent lamp, and furthermore, it is possible to reduce the shadow voltage, thereby reducing the power required to obtain the same luminous flux value. A fluorescent lamp with high lamp efficiency can be obtained.

[Brief explanation of drawings]

1 is a side view showing a partial cross section of a lamp according to an embodiment of the present invention, and FIGS. 2, 3, and 4 are perspective views of an electrode section according to an embodiment of the present invention. 1...Glass tube, 2...phosphor, 3...mercury, 4
...Third item included

Claims (1)

[Claims] 1. The tube contains an inert gas and mercury as a sealed gas,
A fluorescent lamp comprising a phosphor attached to the inner surface of a glass tube, characterized in that a cylindrical electrode made of tungsten is used as the structure of the electrodes at both ends. 2. The fluorescent lamp according to claim 1, wherein numerous holes are provided on the side surface of the cylindrical electrode. 3. The fluorescent lamp according to claim 1 or 2, characterized in that an electrode is used in which the inside of the cylindrical electrode is filled with an oxide containing barium oxide.