JPH0757689A - Discharge tube - Google Patents

Abstract

PURPOSE:To realize the long service life. CONSTITUTION:A pair of electrode devices 4A arranged opposite on both end sides of a glass tube 1 are composed of a column shape electrode 41 arranged in the tip part of an inner lead 3 and a cup shape electrode 42 to surround this column shape electrode 41. This column shape electrode 41 is formed by impregnating an emitter material as an electron emitting body or by applying it to a surface, and a groove 4a having a recessed shape cross section in the circumferential direction is formed almost in a central part of a main body of this column shape electrode 41, and thereby, an electric current flowing to this column shape electrode 41 is decreased and a calorific value is increased, and thermoelectron emitting efficiency is improved, and a scattering and vaporizing quantity of an electron emitting substance is reduced, and the service life is lenghtened.

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 formed by opposing a pair of electrode devices each composed of an electron emission electrode and a metallic cup-shaped electrode surrounding the outer periphery of the electron emission electrode, and more particularly to the structure of the electrode device. .

[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 is formed in a cylindrical shape made of a sintered metal body that emits thermoelectrons. The glass tube 1 is filled with a mixed gas of, for example, argon gas and mercury for discharging.

The discharge tube thus constructed functions as an arc discharge electrode and a glow discharge electrode because these electrode devices 4 are formed by containing or coating an emitter material as thermionic emission material, Due to the synergistic effect of both, ultra-high brightness discharge can be stably 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 has a first electrode that scatters and evaporates and emits an electron emitting substance; and a first electrode that covers the first electrode and A second electrode for trapping the electron-emissive material that is scattered and emitted by evaporation;
The first electrode has a groove formed in the circumferential direction.

[0008]

The electrode device according to the present invention is provided with a second electrode which covers the first electrode and captures the electron emitting substance scattered and vaporized and emitted from the first electrode. The first electrode is arranged in the circumferential direction. By forming the groove, the current flowing through the first electrode is narrowed down, the amount of heat generated is increased, the thermionic emission efficiency is improved, and the scattered evaporation of the amount of electron emitting material is reduced, so that the life is extended.

[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 FIG. 1, a pair of electrode devices 4A facing each other on both ends of a glass tube 1 having a diameter of 4 mm and a length of 260 mm includes a cylindrical electrode 4 ₁ provided at the tip of the inner lead 3 and the cylindrical electrode 4 _1. It is composed of a cup-shaped electrode 4 ₂ surrounding 4 ₁ .

The cylindrical electrode 4 ₁ is formed by impregnating or coating the emitter material as an electron emitter on the surface thereof, and further, in a substantially central portion of the main body of the cylindrical electrode 4 ₁ , a cross section is formed in the circumferential direction. A groove 4a having a concave shape is formed. Also, the cup-shaped electrode 4 ₂ is formed in a conical shape the aluminum sheet material by press molding. The Al cup-shaped electrode 4 ₂ is inserted into the inner lead 3 and is caulked and fixed to the inner lead 3 at the root portion thereof. Further, the opening end side of the Al cup-shaped electrode 4 ₂ is the tip of the columnar electrode 4 ₁ . It is formed to be longer in the axial direction than the portion and is arranged on the concentric shaft.

In such a structure, the cylindrical electrode 4 ₁
Is contained in the Al cup-shaped electrode 4 ₂ formed in a conical shape, thereby raising the temperature of the cylindrical electrode 4 ₁ to an appropriate temperature for emitting the thermoelectrons E, and forming the groove 4 a in the circumferential direction. by forming the so current flow is narrowed down by the groove 4a, it is more amount of heat generated at the tip portion of the cylindrical electrodes 4 _1, electron emission efficiency is further improved, can be high luminance. Further, the cup-shaped electrode 4 ₂ is a cup-shaped electrode 4 ₂ while preventing the blackening due to the thermionic emission material which is sputtered by the ion bombardment of the cylindrical electrode 4 _{1 and} is scattered and evaporated or the electrode member is attached to the inner surface of the glass tube 1. Thermionic emission by the electron emitting substance attached to the inner surface of the electrode 4 ₂ can be used.

Further, the cylindrical electrodes 4 ₁ and the electron emissive material
Since the effect of regenerating the electron emitting substance can be utilized by reattaching it to the inner surface of the electrode, the consumption of the electron emitting substance is extremely reduced, a sufficient discharge current is obtained, and the amount of light emission is increased. And a long life can be achieved.

In the above-described embodiment, the case where the groove 4a formed in the columnar electrode 4 ₁ has a concave cross section has been described, but this shape is formed in various shapes such as a curved surface or a triangular shape. Needless to say, the same effect as described above can be obtained even if a plurality of such elements are provided.

[0014]

As described above, according to the present invention,
At least one of the pair of electrode devices has a first electrode that scatters and evaporates and emits an electron emitting substance, and a second electrode that covers the first electrode and that captures the electron emissive substance that is scattered and emitted and emitted from the first electrode. Since the first electrode is provided with a groove in the circumferential direction, the current flowing through the first electrode is narrowed down, the amount of heat generated is increased, the thermionic emission efficiency is improved, and the amount of electron emission material is increased. Since the scattered evaporation is reduced,
It has an extremely excellent effect 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 ₁ Cylindrical Electrode 4 ₂ Cup-shaped Electrode 4a Groove

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 includes a first electrode that scatters and evaporates and emits an electron emitting substance, and a second electrode that covers the first electrode and that captures an electron emissive substance that is scattered and emitted and emitted from the first electrode. The first electrode is a discharge tube characterized in that a groove is formed in the circumferential direction.