JPH0613022A - Discharge tube - Google Patents

Abstract

PURPOSE:To reduce the consumption of a first electrode and to achieve long life. CONSTITUTION:A tungsten rod 5 is connected to the front end part of an inner lead 3, which penetrates the end part of a glass tube 1, and is held in this glass tube 1. The front end part of the tungsten rod 5 penetrates a first electrode 41A, which is made of tungsten sintered compact, containing an electron emitting material. A conical second electrode 42A is caulked and fixed to the outer peripheral surface of the first electrode 41A, and an electrode device 4A is thus provided. A length (t) from the discharge surface of the first electrode 41A to the front end part of the tungsten rod 5 is protruded by approximately 0.5mm.

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 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. 2 is a diagram for explaining the structure of this type of discharge tube, FIG. 2 (a) is a sectional view, and FIG. 2 (b) is an enlarged perspective view of a main part of the electrode device. In FIG. 2 (a), 1 is a transparent glass tube forming the main body of the discharge tube, 2 is a fluorescent substance applied to 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 held 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. 2 (b), 4 ₁ a first electrode that emits formed of a sintered metal body and thermal electrons including electron emitting substance at the tip of the inner lead 3, 4 ₂ the first This is a conical second electrode made of, for example, an aluminum molded body that is concentrically arranged by caulking and fixing so as to surround the _first electrode 41.

In such a structure, the pair of electrode devices 4 arranged to face each other is composed of the second electrode 4 ₂ surrounding the first electrode 4 ₁ , and these are arranged adjacent to each other. The electrode 4 _{1 of the above} is impregnated or coated on the surface with an emitter material as a thermionic emission 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. A super-high-intensity discharge is stably obtained, and the thermionic emissive material which is sputtered by the ion bombardment of the first electrode 4 ₁ and evaporates and evaporates, is trapped on the inner surface of the second electrode 4 ₂ . Without causing internal blackening,
The trapped thermoelectron emitting substance is used as an electron emitting substance on the second electrode 4 ₂ and is repeatedly captured by the first electrode 4 ₁ again to obtain a long-life discharge tube.

[0006]

However, in the discharge tube having such a structure, when a large amount of discharge current is passed in order to emit high-luminance light, the first electrode 4 _{1 as} shown in FIG. The amount of sputter due to cations on the discharge surface of
There is a problem that the first electrode 4 ₁ is heavily consumed and 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 an object thereof is to reduce the consumption of the above-mentioned first electrode and realize a long life. To provide.

[0008]

In order to achieve such an object, the present invention provides a tip end portion of a lead wire inserted in a first electrode portion so as to protrude from a discharge surface of the first electrode portion. It is a thing.

[0009]

In the first electrode portion of the present invention, by projecting the lead wire, the ion impact on the discharge surface is alleviated.

[0010]

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 of an electrode device part showing a configuration according to an embodiment of a discharge tube according to the present invention, and the same parts as those in the above-mentioned drawings are designated by the same reference numerals. In the figure, a tungsten rod 5 is connected to the tip of an inner lead 3 which is held in the glass tube 1 by penetrating both ends of the glass tube 1, and an electron is attached to the tip of the tungsten rod 5. the first electrode 4 _1A of tungsten sintered body containing emissive material is disposed is penetrated.

The first electrode _41A is formed by mixing powdery tungsten with electron-emitting material such as barium or cesium, and press-molding the tip of the tungsten rod 5 into a cylindrical shape using a die. It is formed by sintering. In this case, the tungsten rod 5 is formed so that its tip portion projects from the discharge surface of the first electrode _{41A by} a length t of about 0.5 mm.

Further, the second electrode 4 _2A, the entire exterior shape of the aluminum material by press molding is formed into a generally conical shape, fixed by caulking to the outer peripheral surface of the first electrode 4 _1A,
The openings are coaxially arranged so as to face each other.

The second electrode 4 _2A having a conical shape as described above is a cylindrical first electrode 4 _1A formed of a sintered metal body at the tip of the tungsten rod 5 and impregnated with an electron emitting substance. 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 tungsten rod 5.

In such a structure, the first electrode 4 _1A
While preventing the electrode member and the electron emitting substance from scattering to the inner surface of the glass tube 1, thermionic emission due to the electron emitting substance attached to the inner surface of the second electrode _42A can be utilized, and the thermionic emitting substance can also be used. By reattaching to the surface of the first electrode _41A, the effect of regenerating thermionic emission can be utilized, and a long life can be achieved.

According to such a configuration, the electrode device 4A
, By which is projected the tip of the tungsten rod 5 from the discharge surface of the first electrode 4 _1A, since ion bombardment in the discharge surface of the first electrode 4 _1A is relaxed, the sputtering amount is reduced, this The consumption of the discharge surface is reduced. Hence exhaustion of the first electrode 4 _1A decreases, correspondingly service life is prolonged.

Further, according to this structure, since the second electrode _42A is formed of a molded body of an aluminum material, it is relatively difficult to be sputtered by an electron or ion bombardment, so that the inside of the glass tube 1 is prevented. It is possible to improve the shortening of life due to blackening of the tube wall.

In the above-described embodiment, the case where the second electrode _42A is formed in a substantially conical shape as a whole has been described. However, the conical deformable body, the cylindrical deformable body or the deformed body thereof may be used. Of course, it may be formed in various shapes.

[0018]

As described above, according to the present invention,
By projecting the tip portion of the lead wire inserted through the first electrode portion from the discharge surface of the first electrode portion, the ion impact on the discharge surface of the first electrode portion is alleviated, and the electrode member Since the consumption is reduced, the service life is extended correspondingly, and an extremely excellent effect such that a long-life discharge tube is obtained can be obtained.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part of an electrode device portion showing a configuration according to an embodiment of a discharge tube according to the present invention.

FIG. 2A is a cross-sectional view showing the configuration of a conventional discharge tube,
FIG. 3B is an enlarged cross-sectional view of a main part showing the configuration of the electrode device.

[Explanation of symbols]

1 Glass Tube 2 Fluorescent Material 3 Inner Lead 4A Electrode Device 4 _1A First Electrode 4 _2A Second Electrode 5 Tungsten Rod

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Kawai 700 Wada, Ueno Town, Ise City, Mie Prefecture, Ise Denshi Kogyo Co., Ltd. Company Noritake Company Limited (72) Inventor Yoshiyuki Okubo 3-1, 36 Noritake Shinmachi, Nishi-ku, Nagoya-shi Stock company Noritake Company Limited 3-72 (36) Inventor Sato Fuyu 3-36, Noritake Shincho, Nishi-ku, Nagoya Ceremony Company Noritake Company 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 is provided in which a tip portion of a lead wire inserted through the first electrode portion is provided so as to project from a discharge surface of the first electrode portion.