JPH0757700A - Discharge tube - Google Patents

Abstract

PURPOSE:To realize high intensity light emission in a small type by restraining a temperate rise in the electrode part, and increasing a tube electric current. CONSTITUTION:A pair of electrode devices 4A arranged opposite on both end sides of a glass tube 1 is composed of a column shape electrode 41A arranged in the tip part of an inner lead 3 and an Al cup shape electrode 42A to surround this column shape electrode 41A. A ring shape base 5 having a diaphragm part in the end part is arranged in close contact on the outer peripheral surface of the glass tube 1 opposed to a pair of these electrode devices 4A, and the heat of surface of this base 5 is covered with silicon resin 6, and a tube of the electrode part is radiated.

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. A discharge tube configured by opposingly arranging a pair of electrode devices each including a first electrode portion and a second electrode portion surrounding an outer periphery of the first electrode portion,
Specifically, it relates to a heat dissipation 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, 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, FIG. 2 (b) is an enlarged perspective view of an essential part of the electrode device, and FIG. ) Is a sectional view thereof. In FIG. 2A, 1 is a transparent glass tube whose both ends are hermetically sealed to form a discharge tube body, 2 is a fluorescent surface applied to the inner wall surface of the glass tube 1, and 3 is the length of the glass tube 1. Inner leads 4 held by penetrating the glass tube 1 at the end portions in the direction are composed of composite electrodes arranged coaxially in the longitudinal direction of the glass tube 1 so as to face each other at the tip portions of the inner leads 3. The first electrode device and the second electrode device. The glass tube 1 is filled with a mixed gas of, for example, argon gas and mercury for discharging.

Further, these electrode devices 4 are shown in FIG.
As shown in (b) and (c), the rod-shaped electrode 4 ₁ provided at the tip of the inner lead 3 and the rod-shaped electrode 4 ₁ are crimped and fixed to the inner lead 3 so as to surround the rod-shaped electrode 4 ₁ and arranged on the concentric shaft. It is composed of a cup-shaped electrode 4 ₂ .
Further, the rod-shaped electrode 4 ₁ acts as an arc discharge electrode by impregnating or coating the surface of the sintered body with an emitter material as a thermoelectron emitting substance, and the cup-shaped electrode 4 ₂ is formed by a molded body of a metal plate to perform glow discharge. It works as an electrode, and the synergistic effect of the two makes it possible to stably obtain an ultra-high brightness discharge.

[0005] discharge tube constructed in this way, the rod-shaped electrode 4 ₁ with the discharge tube of the ultra-high luminance can be stably obtained is sputtered by ion bombardment, thermionic emission material scattered evaporation cup-shaped electrode 4 ₂ Glass tube 1 captured on the inner surface of the glass
The trapped thermoelectron emitting material is used as an electron emitting material on the cup-shaped electrode 4 ₂ without causing blackening on the inner surface of the electrode, and is repeatedly captured by the rod-shaped electrode 4 ₁ for a long time. A long-life discharge tube is obtained. A discharge tube of this type is disclosed in, for example, Japanese Patent Application No. 2-318277.

[0006]

However, the discharge tube constructed in this way is arranged in the glass tube 1 when the diameter of the glass tube 1 is limited to meet the demand for downsizing. The electrode diameter of the electrode device 4 is limited, and the electrode area is reduced. Therefore, the cup-shaped electrode 4 ₂ is set to less than the inner diameter of the glass tube 1, yet so that its shape is set in a cylindrical shape. As a result,
The cup-shaped electrode 4 _2, part for emission of electrons E when performing glow discharge is only not being utilized that electrode open end only, thus can not provide sufficient tube current, becomes the light amount is insufficient, There is a problem that high-luminance light emission cannot be obtained.

When the discharge tube thus constructed is used as a backlight system, the temperature rise of the electrode part of the discharge tube is about 100 ° C. or less in view of the peripheral materials composing the backlight system. However, if the diameter of the glass tube 1 becomes smaller in response to the demand for downsizing, the temperature of the electrode portion rises to about 100 ° C.
And the heat dissipation measures were required. For example, pipe diameter 3
In a discharge tube of mm, when a tube current of about 8 mA or more was applied, the temperature of the electrode portion exceeded about 110 ° C., so that it was impossible to supply a current of 8 mA or more.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and the object thereof is to suppress the temperature rise of the electrode portion and increase the tube current to realize a compact and high-luminance light emission. It is to provide a discharge tube.

[0009]

In order to achieve such an object, in the discharge tube according to the present invention, a metal cylinder having a high thermal conductivity is closely arranged on the outer peripheral surface of the glass tube facing the electrode device. A metal cylinder is coated with a heat resistant resin having a large heat capacity.

[0010]

In the present invention, by covering the metal cylindrical body closely arranged on the outer peripheral surface of the glass tube with a heat-resistant resin having a large heat capacity, the heat of the electrode section of the glass tube is radiated to the outside and the temperature of the electrode section is reduced. The rise can be suppressed.

[0011]

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, a pair of electrode device 4A disposed opposite to both ends of the glass tube 1, a cup-shaped electrode 4 _2A surrounding the rod-shaped electrode 4 _1A provided at the distal end of the inner lead 3, the rod-like electrode 4 _1A It consists of and. The rod-shaped electrode _41A is formed by impregnating or coating the surface of the sintered body with an emitter material as a thermoelectron emitting material, and the cup-shaped electrode _42A is formed by press-molding an aluminum plate material, for example. The cup-shaped electrode 4 _2A is inserted into the inner lead 3, surrounds the rod-shaped electrode 4 _1A provided at the tip of the cup-shaped electrode 4 _{2A, and} is caulked and fixed to the inner lead 3 at the root part thereof and arranged on the concentric shaft. Has become.

Further, on the outer peripheral surface of the glass tube 1 which faces the electrode device 4A which is disposed in the glass tube 1 so as to face each other, an end formed of a molded body such as Al or copper as a metal cylinder having high heat conductivity. A ring-shaped mouthpiece 5 having a narrowed portion is inserted and closely arranged, and the outer peripheral surface of the mouthpiece 5 is coated and solidified by applying, for example, a silicone resin 6 as a resin having high heat capacity and heat resistance. Has been done.
The plate thickness of the die 5 is about 0.1 to 0.5 mm, and the resin layer thickness of the silicon resin 6 is about 0.5 to 0.5 mm.
It is about 1.0 mm.

In such a structure, the rod-shaped electrode 4 _1A is included in the cup-shaped electrode 4 _2A , so that the rod-shaped electrode 4 _1A is heated to a temperature suitable for emitting thermoelectrons and emits light with high brightness. Can be made. Further, the cup-shaped electrode 4 _2A is formed in a cup-shaped shape while preventing the rod-shaped electrode 4 _1A from being sputtered by ion bombardment and being scattered and vaporized by thermionic emission material or the electrode member to prevent blackening due to adhesion to the inner surface of the glass tube 1. Thermionic emission due to the electron emitting substance attached to the inner surface of the electrode 4 _2A can be utilized, and the regenerating effect of the electron emitting substance can be utilized by reattaching the electron emitting substance to the surface of the rod-shaped electrode 4 _1A , resulting in a long life. Can be achieved, a sufficient discharge current can be obtained, the amount of light is increased, and high-luminance light emission can be obtained.

Further, according to such a constitution, the cap 5 is closely arranged on the outer peripheral surface of the glass tube 1 facing the electrode devices 4A arranged at both ends in the glass tube 1,
The heat emitted from the electrode device 4A and conducted to the glass tube 1 is conducted to the base 5, and the heat conducted to the base 5 passes through the silicone resin 6 coated on the outer peripheral surface of the base 5 to the glass. The heat is dissipated or insulated to the outside of the tube 1.

Table 1 below shows that a cap 5 is provided on the outer peripheral surface of the glass tube 1.
The discharge tube according to the present embodiment in which is coated with a silicone resin 6, the discharge tube of the conventional structure without the base 5, and the base 5 simply.
It shows the results of measuring the tube current and the tube temperature of the electrode section of a conventional structure of a heat radiating tube with only attached.
As can be seen from Table 1, in the structure of the discharge tube according to the present embodiment, it was confirmed that the tube temperature of the electrode part was significantly reduced as compared with the conventional structure while maintaining the tube current at the same level as in the conventional case. .

[0016]

[Table 1]

In the above-mentioned embodiment, the case where the silicon resin is used as the heat-resistant resin for covering the die 5 closely arranged on the outer peripheral surface of the glass tube 1 has been described, but the present invention is not limited to this. The same effect as described above can be obtained by coating the base 5 with a thermosetting shrinkable tube or the like.

Further, in the above-described embodiment, the cap 5 having a narrowed portion on the end side as a metal cylinder having high thermal conductivity.
However, the same effect as described above can be obtained by using a substantially perfect ring-shaped cylindrical body having no narrowed portion on the end side.

Further, in the above-mentioned embodiment, the case where the cup-shaped electrode _42A is formed of an aluminum material has been described, but it may be formed of a nickel material, or 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.

[0020]

As described above, according to the present invention,
By placing a metal cylinder with high thermal conductivity in close contact with the outer peripheral surface of the glass tube facing the electrode device and coating this metal cylinder with a heat-resistant resin with a large heat capacity, the heat of the glass tube electrode part was diffused. Since the heat dissipation and the heat insulating effect are well balanced in the outside and the rise of the temperature of the outer wall of the tube can be suppressed, the tube current is increased and the small size and high brightness light emission can be obtained.

[Brief description of drawings]

FIG. 1A is a cross-sectional view of a main part showing a configuration of an embodiment of a discharge tube according to the present invention, and FIG. 1B is a cross-sectional view taken along the line BB ′.

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 5 Base 6 Silicon Resin

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiyuki Okubo 3-36 Noritake Shinmachi, Nishi-ku, Nagoya-shi, Aichi Noritake Company Limited Limited (72) Inventor Sato Fuyu 3-chome, Noritake Shin-cho, Nishi-ku, Nagoya, Aichi No. 1-36 Noritake Company Limited (72) Inventor Go Maeda No. 1-336 Noritake Shinmachi, Nishi-ku, Nagoya-shi Aichi Prefecture Noritake Company Limited (72) Inventor Tokuhide Shimojo Ueno, Ise City, Mie Prefecture Town 700 Wada, Ise Electronics Industry Co., Ltd. (72) Inventor Masao Uchiyama 700 Wada, Ueno Town, Ise City, Mie Prefecture Ise Electronics Industry Co., Ltd.

Claims (1)

[Claims] 1. A discharge tube in which a pair of electrode devices are opposed to each other in a discharge space in which at least a rare gas and mercury are sealed in a hermetically sealed glass tube, wherein the electrode device housed in the glass tube A discharge tube characterized in that a metal cylinder having a high thermal conductivity is arranged in close contact with the outer peripheral surface of a facing glass tube, and the metal cylinder is covered with a heat-resistant resin having a large heat capacity.