JPH0613023A - Discharge tube - Google Patents

Abstract

PURPOSE:To achieve emission at high brilliance by increasing a discharge current by means of increasing the discharge area of a first electrode. 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. The front end part of the tungsten rod 5 inserted into the first electrode 41A is provided on the inside of the thermionic emitting surface.

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. Thermionic emission material or the electrode member and the second electrode 4 ₂ first electrode 4 ₁ with discharge ultra high brightness can be obtained stably are being spatter evaporated by ion bombardment
Since it is trapped on the inner surface of the glass tube 1, the inner surface of the glass tube 1 is not blackened, and the trapped thermoelectron emitting material is used as the electron emitting material on the second electrode 4 _2. discharge tube long life can be obtained by repeating the be reattached to the 4 _first surface.

[0006]

However, the discharge tube configured as described above has the first structure as shown in FIG. 2 (b).
The electrode 4 contributes discharge surface on _one of the thermionic emission flush has a configuration in which the distal end surface of the inner lead 3 is arranged, it is possible to obtain a thermal electron emission from the distal end surface of the inner leads 3 However, the high brightness emission was hindered.

Therefore, the present invention has been made in order to solve the above-mentioned conventional problems, and its object is to increase the amount of electron emission of the above-mentioned first electrode for high-luminance light emission. An object is to provide a discharge tube that can provide a long life.

[0008]

In order to achieve such an object, the present invention is arranged such that the tip end portion of a lead wire that passes through the first electrode portion is stopped inside the radiation surface of the first electrode portion. By doing so, a concave portion is formed in the central portion of the first electrode portion.

[0009]

In the first electrode portion of the present invention, the tip of the lead wire is arranged inside the electron emission surface, so that the electron emission surface of the first electrode portion is substantially enlarged. Become.

[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 radiation material is arranged to penetrate, the electrode device 4A
Is part of the.

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, tungsten rod 5 has a length t in the inward direction the distal end from the thermionic emission surface of the first electrode 4 _1A
Are arranged at a distance of about 0.5 mm or more.

A second part of the electrode device 4A is also provided.
The electrode 4 _2A of the first electrode 4 _2A is formed by press-molding an aluminum material so that the entire external shape is formed into a substantially conical shape.
The outer peripheral surface of _1A is caulked and fixed, and the openings are concentrically 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 coaxially 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. It is possible to extend the service life by reattaching to the surface of the first electrode _41A .

According to such a configuration, the electrode device 4A
The first electrode _41A is configured by arranging the tip end portion of the tungsten rod 5 inside from the electron emission surface thereof.
The electrode surface area that becomes the electron emission surface is substantially expanded, and high-luminance light emission is performed, so that the load per unit area of the first electrode _41A when a large amount of discharge current is flowed is reduced, The electrode life is extended.

Further, according to such a structure, in the electrode device 4A, since the second electrode _42A is formed of a molded body of an aluminum material, it is relatively difficult to be sputtered by electrons, ion bombardment, etc. It is possible to improve the decrease in the life due to the blackening of the tube wall in the glass tube 1, and to extend the life of the discharge tube.

Further, the discharge tube thus constructed is
As a result of the inventors making a large amount of samples and performing the luminance measurement test a plurality of times, the emission luminance could be improved by about 25% or more of the conventional level without impairing other electrical characteristics.

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, a conical deformable body, a cylindrical shape or a deformed body thereof may be used. Of course, it may be formed in various shapes.

Further, in the above-described embodiment, the first electrode 4 _1A is arranged by stopping the leading end portion of the lead wire passing through the first electrode 4 _1A inside the discharge surface of the first electrode 4 _{1A. The} case where the concave portion is formed in the central portion of _1A has been described, but the concave portion in the central portion of the first electrode 41A is formed by forming concentric concave portions in two or three steps larger than the diameter of the lead wire. Of course, it is also good.

[0020]

As described above, according to the present invention,
By disposing the tip end portion of the lead wire inserted through the first electrode portion inside from the electron emission surface of the first electrode portion, the electron emission surface of the first electrode portion is substantially enlarged. Therefore, the amount of thermionic emission is increased, the amount of emitted light is increased, and a discharge tube with high-luminance light emission 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, the first electrode portion has a recessed portion formed in a central portion thereof.