JPH09259818A - Electric discharge tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sputtering resistance of a second electrode by glow discharge, reduce the occurrence of blackening phenomenon, and extend the life by forming the second electrode of a nickel (alloy body) having a low sputtering ratio by positive ion. SOLUTION: A second electrode 42 A surrounding a first electrode 41 A provided on the tip of an inner lead 3 is formed to have a cup-like outer shape by hot press molding. The second electrode 42 A is formed of a sintered metal on the tip of the inner lead 3, and it is caulked to the base so as to surround the outer circumferential part of the cylindrical first electrode 41 A impregnated with an electron emitting material, and arranged in a prescribed position concentrically to the inner lead 3.

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 constituted 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 an electrode device composed of a first electrode part and a second electrode part surrounding the outer periphery of the first electrode part is arranged to face each other, and more specifically to an electrode structure of the electrode device. It is a thing.

[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, higher brightness and longer life are required.

FIG. 3 is a diagram for explaining the structure of this type of discharge tube, FIG. 3 (a) is a sectional view, and FIG. 3 (b) is an enlarged perspective view of essential parts of the electrode device. In FIG. 3 (a), 1 is a transparent glass tube that forms the main body of the discharge tube, 2 is a phosphor coated on the inner wall surface of the glass tube 1, and 3 is the glass tube at the longitudinal end of the glass tube 1. Inner leads 4 penetrating through 1 are a pair of electrode devices which are arranged coaxially in the longitudinal direction of the glass tube 1 so as to face each other at the tip of each inner lead 3. The glass tube 1 is filled with a mixed gas of, for example, argon gas and mercury for discharging.

Further, in FIG. 3B, reference numeral 4 ₁ denotes a first electrode which emits thermoelectrons formed of a sintered metal body at the tip of the inner lead 3 and 4 ₂ denotes the first electrode 4 _1. Is a cup-shaped second electrode formed of a molded body of an aluminum material which is concentrically arranged by penetrating the inner lead 3 so as to surround it and crimping and fixing its root portion.

In such a structure, the pair of electrode devices 4 arranged to face each other is composed of the first electrode 4 ₁ and the second electrode 4 ₂ , which are arranged adjacent to each other. First
The electrode 4 _{1 of the above} is impregnated or coated on the surface with an emitter material as a thermoelectron emitting substance, and it functions as an arc discharge electrode, and the second electrode 4 ₂ functions as a glow discharge electrode. A stable discharge can be obtained.

As a result, an ultra-high-luminance discharge tube can be stably obtained, and the first electrode 4 ₁ is sputtered by ion bombardment, and the thermionic emission material that is scattered and evaporated is the second electrode 4
Without causing trapped ₂ of the inner surface inner surface blackening of the glass tube 1, the captured thermal electron emitting substance and the second electrode 4 ₂
A discharge tube having a long life can be obtained by repeating the above-mentioned use as an electron emitting substance and trapping again by the first electrode 4 ₁ . A discharge tube of this type is disclosed in, for example, Japanese Patent Application No. 2-318277.

[0007]

[0007] However, in thus constructed discharge tube, the second electrode 4 ₂ is because it is made of aluminum material, although with very high electron emission ability, low melting point metal Therefore, there is a problem that the life of the discharge tube is shortened because sputtering is likely to occur due to impact of cations due to glow discharge.

Further, the aluminum metal particles by the impact of positive ions in the glow discharge of the second to the electrode 4 ₂ is formed a second electrode 4 ₂ is attached against the inner wall of the glass tube 1 to generate a blackening However, there is a problem that the life of the discharge tube is shortened.

Therefore, the present invention has been made in order to solve the above-mentioned conventional problems, and its purpose is to improve the sputtering resistance of the second electrode due to the above-mentioned glow discharge, and to make the blackening phenomenon. An object of the present invention is to provide a discharge tube capable of realizing a long life by reducing the occurrence of

[0010]

In order to achieve such an object, the present invention forms a second electrode portion of nickel or a nickel alloy body having a low sputtering yield due to cations, so that The consumption of the metal body forming the second electrode due to the impact is reduced.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration according to an embodiment of a discharge tube according to the present invention.
1A is a sectional view, and FIG. 1B is an enlarged perspective view of a main part of the electrode device, and the same parts as those in the above-mentioned drawings are denoted by the same reference numerals. In the figure, the electrode device 4A, heat the second electrode 4 _2A is nickel or nickel alloy material as shown in FIG. 1 (b) surrounding the first electrode 4 _1A provided at the distal end of the inner lead 3 The entire outer shape is formed into a cup shape by hot press molding.

The cup-shaped second electrode 4 _2A is a cylindrical first electrode 4 _1A formed of a sintered metal body at the tip of the inner lead 3 and impregnated with an electron emitting material. The first electrode _41A is surrounded by the outer periphery of the first electrode _41A and is caulked and fixed at its root portion, and is arranged at a predetermined position concentrically with the inner lead 3.

According to this structure, the second electrode 4 _2A
By forming a nickel or nickel alloy material, since the scattering of the metal particles by positive ion impact is very small, depletion of the metal body of the second electrode 4 _2A decreases. Also, the adhesion to the inner wall surface of the glass tube 1 disappears,
The occurrence of the blackening phenomenon disappears. Therefore, as shown in FIG. 2, as compared with the second electrode 4 ₂ made of a conventional aluminum material, the luminance maintenance factor is maintained for a long time (about 20000 hours), so that the life of the discharge tube can be significantly improved. .

Further, since the first electrode 4 _1A is included in the cup-shaped second electrode 4 _2A , the first electrode 4 _1A has a temperature suitable for emitting thermoelectrons. It can be raised to emit light with high brightness. Furthermore, the cup-shaped second electrode 4 _2A is blackened by thermionic emission material which is sputtered by the first electrode 4 _{1A when it} is ion-impacted and is scattered and evaporated, or the electrode member adheres to the inner surface of the glass tube 1. while preventing, available thermionic emission by the electron emitting materials attached to the inner surface of the second electrode _2A, also, the electron emission substance by causing redeposition the electron emission substance on the surface of the first electrode 4 _1A The regeneration effect can be used and the life can be extended.

In the above-described embodiment, the second
The electrode _42A of _{No. 1} has been described in the case where the entire shape thereof is formed in a cup shape, but it is needless to say that the electrode _42A may be formed in various shapes such as a cup-shaped deformed body, a conical shape, or a deformed body thereof. .

[0016]

As described above, according to the present invention,
Since the second electrode is formed of nickel or its alloy body having a low sputtering yield due to cations, the sputtering resistance due to cation bombardment is improved, so that the metal body forming the second electrode is less consumed. In addition, the blackening of the inner surface of the glass tube can be reduced, which has an extremely excellent effect such that a long-life discharge tube can be obtained.

[Brief description of drawings]

1A is a cross-sectional view showing a configuration according to an embodiment of a discharge tube according to the present invention, FIG. 1B is an enlarged perspective view of an essential part showing a configuration of an electrode device, and FIG. 1C is a configuration of the electrode device. It is a principal part expanded sectional view shown.

FIG. 2 is a diagram showing the luminance maintenance rate of the discharge tubes of the present invention and the conventional configuration.

FIG. 3A is a cross-sectional view showing the structure of a conventional discharge tube,
(B) is an enlarged perspective view of a main part showing the configuration of the electrode device.

[Explanation of symbols]

1 ... Glass tube, 2 ... Phosphor, 3 ... Inner lead, 4A
... Electrode device, _41A ... First electrode, _42A ... Second electrode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sato Fuyu Aichi Prefecture Noritake Shincho 3-3-1, Nishi-ku, Nagoya-shi, Aichi Prefecture Noritake Co., Ltd. Limited (72) Inventor Takeshi Maeza 3-chome Noritake Shin-cho, Nishi-ku, Nagoya Aichi Prefecture No. 36 Noritake Company Limited Limited

Claims (1)

[Claims] 1. A discharge comprising a pair of electrode devices arranged opposite to each other in a discharge space and having a first electrode portion connected to an inner lead and a second electrode portion surrounding the outer periphery of the first electrode portion. In the tube, a discharge tube characterized in that the second electrode portion is made of nickel or a nickel alloy body having a low sputtering yield due to cations.