JPH0721977A - Discharge tube - Google Patents

Abstract

PURPOSE:To realize a long service life as well as to obtain a high luminance luminescence in a small size. CONSTITUTION:Each of a pair of electrode devices 4A provided opposing at both end sides of a glass tube 1 is composed of a cylindrical electrode 41A provided on top of an inner lead 3, and an Al cup form electrode 42A surrounding the cylindrical electrode 41A. And the cylindrical electrode 41A is formed by including about 75wt.% to the W sintered body, of (La, Sr) MnO3 as a perobskite type compound oxide, to a sintered body of W, for example. And the Al cup electrode 42A is formed by forming an aluminum plate material in a conical form by a press moulding process. And the Al cup form electrode 42A is inserted to the inner lead 3, and it is fixed to the inner lead 3 by its base part by a calking, while surrounding the cylindrical electrode 41A provided on top of the inner lead 3, and it is provided on a concentric axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge tube applied to, for example, a backlight for a liquid crystal panel, and in particular, it is constructed by enclosing a rare gas and mercury in a glass tube and connected to inner leads at both ends. The present invention relates to a discharge tube in which a pair of electrode devices composed of a sintered electrode and a metallic cup-shaped electrode surrounding the outer periphery of the sintered electrode are arranged to face each other, and more specifically, a sintered electrode forming the electrode device. Is related to the structure of.

[0002]

2. Description of the Related Art With recent advances in liquid crystal technology, liquid crystal display panels have come to be widely used in various display devices. Recently, a liquid crystal display device using this liquid crystal display panel has been strongly demanded to be particularly small and lightweight, and in order to satisfy the requirements relating to such a liquid crystal display device, a discharge tube is widely used as a backlight of the liquid crystal display panel. Has been adopted.
Therefore, in order to manufacture a miniaturized liquid crystal display device, it has been particularly required to improve the liquid crystal display panel and miniaturize the backlight. At the same time, in order to improve the display quality of the liquid crystal display device, higher brightness and longer life are required.

FIG. 2 is a diagram for explaining the structure of this type of discharge tube. FIG. 2 (a) is a perspective view of an electrode device, and FIG. 2 (c).
Is a sectional view thereof. In FIG. 2, 1 is a transparent glass tube whose both ends are hermetically sealed to form a discharge tube main body, 2 is a fluorescent surface applied to the inner wall surface of the glass tube 1, and 3 is both ends in the longitudinal direction of the glass tube 1. The inner leads 4 held by penetrating the glass tube 1 are electrode devices that are arranged on the tip ends of the inner leads 3 so as to face each other and coaxially in the longitudinal direction of the glass tube 1. The electrode device 4 includes, for example, (La, Sr) MnO ₃ or (La, Sr) CoO ₃ as an electron emitting substance in a tungsten (W) sintered body.
Etc. is formed by being impregnated with about 50 wt% or applied on the surface. The glass tube 1 is filled with a mixed gas of, for example, argon gas and mercury for discharging.

In the discharge tube thus constructed, these electrode devices 4 are used as thermionic emission materials (La, S) in the sintered body.
r) MnO ₃ or (La, Sr) CoO ₃ is formed by being impregnated or coated on the surface, so that it functions as an arc discharge electrode and a glow discharge electrode, and the synergistic effect of both stabilizes the discharge of ultra-high brightness. Obtained.

[0005]

However, in the discharge tube constructed in this manner, the pair of electrode devices 4 are heavily sputtered by ion bombardment, so that the amount of electron-emissive substances is scattered and evaporated, resulting in a short service life. However, there is a problem that the life is not easily extended.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide a discharge tube capable of realizing a long life.

[0007]

In order to achieve the above object, the discharge tube according to the present invention has an inner lead in a discharge space in which at least a rare gas and mercury are enclosed in a glass tube whose both ends are hermetically sealed. A pair of electrode devices connected to each other are opposed to each other, and at least one of the pair of electrode devices is made of a heat-resistant metal that scatters and emits an electron emitting substance, and a sintered electrode that covers the sintered electrode and The sintered electrode comprises a metal cup-shaped electrode that captures an electron emitting substance scattered and evaporated and emitted from the electrode. This sintered electrode contains a perovskite-type composite oxide as an electron emitting substance in an amount of 50 to 95% by weight with respect to a heat-resistant metal. It is contained in the range.

[0008]

The electrode device according to the present invention comprises a sintered electrode made of a heat-resistant metal, and a metallic cup-shaped electrode which covers the sintered electrode and captures an electron emitting substance scattered and vaporized and emitted from the sintered electrode. The sintered electrode is composed of a perovskite-type complex oxide as an electron emitting substance, which is 5 to the heat-resistant metal.
When the content is in the range of 0 to 95% by weight, sufficient thermionic emission efficiency and discharge electrode area are secured, and sufficient discharge characteristics are obtained.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an enlarged cross-sectional view of an essential part showing the configuration of an embodiment of a discharge tube according to the present invention, and the same parts as those in FIG. 2 are designated by the same reference numerals. In Figure 1, the diameter 4 mm, a pair of electrode device 4A disposed opposite to both ends of the glass tube 1 of length 260mm is a cylindrical electrode 4 _1A provided at the distal end of the inner lead 3, the cylindrical electrodes It is composed of an Al cup electrode 4 _2A surrounding 4 _1A . The columnar electrode _41A is made of, for example, a sintered body of tungsten (W) as a perovskite complex oxide (La, Sr).
MnO ₃ is formed to be contained in about 75 wt% with respect to the W sintered body, and the Al cup electrode _42A is formed in a conical shape by press molding an aluminum plate material. The Al cup-shaped electrode 4 _2A is inserted into the inner lead 3 and surrounds the cylindrical electrode 4 _1A provided at the tip of the inner lead 3 and surrounds the inner electrode 3 at the base portion.
It is fixed by crimping and is arranged on the concentric shaft.

In such a structure, the cylindrical electrode _41A
There by being encapsulated in Al cup-shaped electrode 4 _2A which is formed into a conical shape, can be cylindrical electrodes 4 _1A is raised to a temperature suitable to release thermoelectrons, thereby high luminance. Further, the cup-shaped electrode 4 _2A is a cup-shaped electrode 4 _1A while preventing blackening due to adhesion to the inner surface of the glass tube 1 by a thermoelectron emitting substance or electrode member that is scattered and evaporated when the cylindrical electrode 4 _1A is sputtered by ion bombardment. Electrode 4 _2A
Since thermionic emission due to the electron emitting substance attached to the inner surface of the electron emitting substance can be used, and the regenerating effect of the electron emitting substance can be used by reattaching the electron emitting substance to the surface of the cylindrical electrode _41A , the electron emitting substance can be used. Consumption is extremely reduced, a sufficient discharge current can be obtained, the amount of light can be increased, high-luminance light emission can be obtained, and a long life can be achieved.

The following Table 1 shows the electrical characteristics of a discharge tube having the above-configured electrode device 4A and a discharge tube of the same size (diameter 4 mm, tube length 260 mm) having the conventional electrode device 4 by experiments. It shows the obtained results. As is clear from Table 1, in the configuration according to the embodiment, the result of the on / off test every 30 seconds is significantly improved as compared with the structure of the conventional discharge tube while maintaining the emission brightness and the emission efficiency of the discharge tube. Was confirmed.

[0012]

[Table 1]

Further, the electrode device 4A thus constructed
As perovskite-type composite oxide in the sintered body of tungsten (W) as the cylindrical electrode 4 _1A (La, Sr)
The case where MnO ₃ is contained in the W sintered body at about 75 wt% has been described.
r) When the content of MnO ₃ is less than 50 wt%, the life is long, but the thermionic emission efficiency is reduced, and 95 wt%
If it exceeds%, it becomes difficult to mold the W sintered body. Therefore, the content of 50 to 95 wt% was extremely effective.

In the above-mentioned embodiments, the case where (La, Sr) MnO ₃ is used as the perovskite type complex oxide has been described, but (La, Sr) CoO is used.
_It goes without saying that the same effect as described above can be obtained by using ₃ .

Further, in the above-mentioned embodiment has described the case of using the W sintered body as an electrode material of the cylindrical electrode 4 _1A, Ti, the same effect as described above even by using a heat-resistant metal such as Nb Of course,

Further, in the above-mentioned embodiment, the case where the cup-shaped electrode _42A is made of an aluminum material has been described, but it may be made of a nickel material, and a mixture of tungsten and nickel is cut by a die. May have a saw-tooth shape, and the whole shape may be formed into a bell shape and then sintered to form a sintered body.

[0017]

As described above, according to the present invention,
A pair of electrode devices connected to the inner leads are arranged opposite to each other in a discharge space in which at least a rare gas and mercury are sealed in a glass tube whose both ends are hermetically sealed, and at least one of the pair of electrode devices is an electron emitting substance. And a cup-shaped metal electrode that covers the sintered electrode and captures the electron emission material that is scattered and vaporized and emitted from the sintered electrode. Since the binding electrode contains a perovskite-type composite oxide as an electron emitting substance in a range of 50 to 95% by weight with respect to the heat-resistant metal, a sufficient thermoelectron emission efficiency and a discharge electrode area can be secured. Discharge characteristics are obtained,
It has an extremely excellent effect such that a small-sized and high-luminance light emission can be obtained and a long-life discharge tube can be obtained.

[Brief description of drawings]

1A is a cross-sectional view showing a structure according to an embodiment of a discharge tube according to the present invention, FIG. 1B is an enlarged perspective view showing a structure of an electrode device, and FIG. 1C is a cross-sectional view thereof.

FIG. 2A is a cross-sectional view showing the configuration of a conventional discharge tube,
(B) is an enlarged perspective view showing the configuration of the electrode device, and (c) is a sectional view thereof.

[Explanation of symbols]

1 Glass Tube 2 Fluorescent Surface 3 Inner Lead 4A Electrode Device 4 _1A Cylindrical Electrode 4 _2A Cup-shaped Electrode

Front page continuation (72) Inventor Yoshiyuki Okubo No. 1-336 Noritake Shinmachi, Nishi-ku, Nagoya, Aichi Prefecture Noritake Company Limited Limited (72) Inventor Sato Winter Season 1-3 Noritake Shin-cho, Nishi-ku, Nagoya, Aichi Prefecture 36-36 Noritake Co., Ltd. in Limited (72) Inventor Takeshi Maejima 1-3-36 Noritake Shinmachi, Nishi-ku, Nagoya, Aichi Prefecture No. 36 Noritake Co., Limited (72) Inventor Tokuhide Shimojo Wada, Ueno-cho, Ise-shi, Mie Address 700 Ise Electronics Industry Co., Ltd. (72) Inventor Masao Uchiyama 700 Wada, Ueno Town, Ise City, Mie Prefecture Address Ise Electronics Industry Co., Ltd.

Claims (1)

[Claims] 1. A pair of electrode devices connected to inner leads are arranged opposite to each other in a discharge space in which at least a rare gas and mercury are sealed in a glass tube whose both ends are hermetically sealed, and at least one of the pair of electrode devices. One is a sintered electrode made of a heat-resistant metal that evaporates and emits an electron emitting substance,
The sintered electrode comprises a metallic cup-shaped electrode that covers the sintered electrode and captures an electron emitting substance that is scattered and evaporatively emitted from the sintered electrode. 50 to 95 for metal
Discharge tube characterized by containing in the range of wt%.