JPH09283076A - Cold-cathode fluorescent discharge tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cold-cathode fluorescent discharge tube capable of obtaining the prescribed luminance over a long period and having a long life by using sintered electrode bodies with the specific composition having a large mercury content at both ends of a glass tube. SOLUTION: This cold-cathode fluorescent discharge tube is constituted of a glass tube 1, a fluorescent film 4 applied on the inner wall of the glass tube 1, the rare gas sealed in the glass tube 1, and electrodes 3 provided at both ends of the glass tube 1. The metal powder constituted of titanium of 90wt.% and tantalum of 10wt.% is molded and sintered to obtain a sintered body having the porosity of 30-40%, and the sintered body is impregnated with mercury and processed at a high temperature to form the electrode 3. The sintered electrode bodies 3 are fitted to metal wires 2 sealed at both opening ends of the glass tube 1, for example, and the impregnated mercury of the sintered electrode bodies 3 is discharged by heat when the opening ends of the glass tube 1 are heated and squeezed to seal the metal wires 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold cathode fluorescent discharge tube used as a back light for office automation equipment such as personal computers and word processors, and liquid crystal televisions, and more particularly to a cold cathode fluorescent discharge tube having a long life.

[0002]

2. Description of the Related Art Cold cathode fluorescent discharge tubes used as backlights for office automation equipment, liquid crystal televisions, and the like are strongly required to have high brightness, long life, and thin tubes due to colorization of liquid crystal display elements and miniaturization. And now has an outer diameter of 2.0 m
A very thin shape with mφ and a total length of 270 mm has been put to practical use.

[0003]

The thinner the tube, the easier it is to incorporate it into the equipment, and there is the advantage that the equipment and device can be made smaller. However, in view of the characteristics of the cold cathode fluorescent discharge tube, due to the high frequency of use of equipment and devices, there is a strict requirement that a predetermined brightness should be obtained over a long period of time, and this long There are many difficulties in dealing with life.

Therefore, an object of the present invention is to provide a so-called long-life cold cathode fluorescent discharge tube which can obtain a predetermined brightness value for a long period of time.

[0005]

In order to achieve the above object, the cold cathode fluorescent discharge tube of the present invention uses a sintered electrode body containing a large amount of mercury at both ends of a glass tube.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is directed to a glass tube, a fluorescent film applied to the inner wall of the glass tube, a rare gas sealed inside the glass tube, and the glass tube. In a cold cathode fluorescent discharge tube consisting of electrodes provided at both ends, the electrodes are made of 90% by weight of titanium and 1% of tantalum.
A cold cathode fluorescent discharge tube which is a sintered electrode body obtained by impregnating a sintered body with 0 wt% of metal powder at a porosity of 30 to 40% with mercury and subjecting it to high temperature treatment. The mercury impregnated in the sintered electrode body is
The glass tube is vaporized and discharged into the glass tube by evacuation, sealing with a rare gas, and heating when sealing both ends of the glass tube. Since the porosity of the sintered electrode body is large and the mercury content is large, a considerable amount of mercury is released.

According to a second aspect of the present invention, the sintered electrode body is attached to a metal sealing body which seals both open ends of the glass tube. Mercury is released from the sintered electrode body when heat-sealed to both open ends.

According to a third aspect of the present invention, the sintered electrode body is attached to a metal wire sealed at both open ends of the glass tube, and the open ends of the glass tube are heated and drawn. The impregnated mercury in the sintered electrode body is released by the heating when the metal wire is sealed and sealed.

An embodiment of the present invention will be described below. (Embodiment 1) FIG. 1 is a cross-sectional view of a cold cathode fluorescent discharge tube according to an embodiment of the present invention, in which 1 is a glass tube, 2 is a glass tube 1 and a metal wire such as a Dumet wire or a tungsten wire which is well compatible with the glass tube 1. 3 is a sintered electrode body attached to the metal wire 2, and 4 is a fluorescent film applied over the entire inner surface of the glass tube 1. As shown in FIG. 3A, the sintered electrode body 3 is provided with pores 5 having a diameter substantially equal to the diameter of the metal wire 2. The metal wire is inserted into this hole and tightened by mechanical pressure to form the metal wire 2. It is fixed.

Now, regarding this sintered metal body, as a result of studying various metal materials, as a result of titanium metal powder 90% by weight, tantalum metal powder 10% by weight, porosity 30-40.
% Was the best for mercury impregnation. An example of how to make it will be described. Metal powders of titanium and tantalum are press-molded in the above ratio and then sintered at a high temperature to obtain a porosity of 30 to 4
Make a 0% sintered body. This porosity is the particle size of the metal powder,
It is mainly adjusted by the pressing force of the press molding, the sintering temperature, etc. Put the sintered body together with mercury in a sealed container at 450-600 ° C.
By applying the high temperature for a long time to react mercury with titanium to form an alloy of titanium and mercury, a sintered electrode body impregnated with mercury is formed.

The sintered electrode body 3 thus manufactured is
The metal wire 2 is attached, and the glass tube 1 coated with the fluorescent film 4 is placed on a jig in a hermetically sealed container for exhausting and sealing,
After exhausting and filling with a rare gas, both ends of the glass tube are heated by high frequency for sealing, and the cold cathode fluorescent discharge tube of FIG. 1 is completed. The high heat at the time of heat-sealing the both ends of the glass tube 1 is also applied to the sintered electrode body 3, and the impregnated mercury is evaporated and released into the glass tube.

In order to confirm the life of the cold cathode fluorescent discharge tube thus manufactured, the glass tube 1 has an outer diameter of 2.6.
mmφ, inner diameter 2.0 mmφ, total length 250 mm, sintered electrode body 3 having 1.0 mmφ, length 2.0 mmφ, pores 5 having a size of 0.5 mmφ, 90% by weight of titanium and 10% by weight of tantalum, A cold cathode fluorescent discharge tube having a porosity of 40% impregnated with mercury and heated at a high temperature, a mixed gas of 5% argon and 95% neon as a gas to be sealed in the glass tube 1 is sealed at 80 Torr to form a cold cathode fluorescent discharge tube. This was prepared and a life test was conducted.

The life was confirmed by the two points of consumption of effective mercury and maintenance of brightness. Regarding the consumption amount of the effective mercury amount, the data measured by the mercury measuring device before lighting the sample n = 5 and the data measured by the mercury measuring device after lighting the sample n = 5 at a tube current of 6 mA for 6,000 hours Compared with. As a result, the amount of mercury enclosed in the glass tube before lighting was 1,050 μg on average, and the amount of mercury after 10,000 hours was 980 μg on average. Therefore, only 70 μg of mercury was consumed by lighting for 6,000 hours. Only.

For maintaining the brightness, a value obtained by measuring the brightness of a part of a glass tube having a size of about 1.5 mmφ after starting lighting with a spot measuring instrument having a measuring angle of 1/3 (average of n = 5) As a result of confirming a decrease in luminance after 10,000 hours, a decrease of about 25% (n =
(Average value of 5) was found, and good results were obtained with respect to maintaining the brightness.

From the above results, it is possible to sufficiently secure a luminance retention rate of 50% or more, which is generally said to be 10,000 hours after lighting, if mercury is sufficiently enclosed, and the cold cathode fluorescent discharge tube of the present invention is obtained. , Can be extremely effective in terms of life.

(Embodiment 2) FIG. 2 is a sectional view showing an embodiment of the present invention, in which the metal sealing bodies 6 shown in the figure are used to seal the openings at both ends of the glass tube 1. 3B, the same sintered electrode bodies 3 and 3 as described above are fixed to the pin 7 at the central portion of the metal sealing body 6 as shown in FIG. , 6 is released into the glass tube 1 by heating when the glass tube 1 is closed.

[0017]

As described above, in the cold cathode fluorescent discharge tube of the present invention, since the sintered electrode body is impregnated with sufficient mercury,
It is possible to secure a sufficient amount of mercury released into the glass tube, and as a result, it is possible to obtain a long-life lamp without a significant decrease in brightness even after long-term use.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a cold cathode fluorescent discharge tube according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of a cold cathode fluorescent discharge tube according to a second embodiment of the present invention.

3A is a perspective view of a sintered electrode body of the cold cathode fluorescent discharge tube according to FIG. 1, and FIG. 3B is a perspective view of a sintered electrode body of the cold cathode fluorescent discharge tube according to FIG.

[Explanation of symbols]

 1 Glass Tube 2 Metal Wire 3 Sintered Electrode Body 4 Fluorescent Film 6 Metal Sealing Body

Claims (3)

[Claims] 1. A glass tube, a fluorescent film applied to the inner wall of the glass tube, and a rare gas sealed inside the glass tube.
In a cold cathode fluorescent discharge tube comprising electrodes provided at both ends of the glass tube, the electrode is formed by impregnating a sintered body with a metal powder of titanium 90 wt% and tantalum 10 wt% at a porosity of 30 to 40% with mercury. A cold cathode fluorescent discharge tube which is a sintered electrode body formed by high temperature treatment. 2. The cold cathode fluorescent discharge tube according to claim 1, wherein the sintered electrode body is fixed to a metal sealing body that seals both open ends of the glass tube. 3. The cold cathode fluorescent discharge tube according to claim 1, wherein the sintered electrode body is attached to a metal wire sealed at both open ends of the glass tube.