JPH09190800A - Cold cathode fluorescent lamp - Google Patents

Abstract

(57) [Abstract] [Problem] Cold cathode with low power consumption, long life, and miniaturization by forming the electrode 5 into a shape in which discharge is likely to occur and using metal of an appropriate material for the lead-in wire 4 for each part Provide a fluorescent lamp. [Solution] Electrodes 5 and 5 made of cold cathodes are sealed at opposite ends inside the glass bulb 1 at opposite positions.
In the cold cathode fluorescent lamp in which the lead-in wire 4 connected to the airtight is led out from the end wall of the glass bulb 1 to the outside, the shape of the electrode 5 is gradually thinned from the base 8 to the inner end 9 and sealed. Wear lead-in line 6 is Kovar, external lead-in line 7
Is characterized by being composed of Jumet.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a word processor,
The present invention relates to a cold cathode fluorescent lamp used as a back light source of a liquid crystal display device used in office automation equipment such as personal computers and liquid crystal televisions, and more specifically, to a structure of a mount of this cold negative fluorescent lamp.

[0002]

2. Description of the Related Art With the widespread use of liquid crystal display devices such as office automation equipment and liquid crystal televisions, consumers are expected to consume less power and have a longer life.
Development of a miniaturized liquid crystal display device is required. In order to meet such market needs, it is necessary to develop a cold cathode fluorescent lamp used as a back light source of a liquid crystal display device, which has lower power consumption, longer life, and smaller size. Is the current situation.

Conventionally, a cold cathode fluorescent lamp of this type will be described with reference to FIGS. 4 and 5. A phosphor coating 2 is formed on the entire inner surface of a glass bulb 1 having a small diameter of 4 mm or less, and a rare gas such as argon gas or xenon gas is sealed inside. The introduction line 4 is formed by linearly forming a sealing introduction line 6 located at the sealing portion and an external introduction line 7 located outside the glass bulb 1 by using different kinds of metals, and forming the different kinds of metal into one piece. It is configured by connecting linearly. An electrode 5 made of a cold cathode is electrically connected to the inner end of the lead-in wire 4 to form a mount 3.
Electrodes 5 and 5 are positioned opposite to each other inside the glass bulb 1, and the sealing introduction line 6 of the introduction line 4 guides the end wall of the glass bulb 1 to the outside in an airtight manner. The walls are configured to fix the internal electrodes 5, 5. Conventionally, there are three types of mounts 3 configured as described above, which will be described below. In the first type, the cold cathode is made of nickel, and the lead wire for sealing and the lead wire for external use are made of dumet. The second one is one in which the cold cathode, the sealing lead-in wire and the external lead-in wire are made of Kovar. Third
Of the cold cathode and the lead wire for sealing is tungsten,
The external lead wire is made of nickel.

[0004]

The first of the above-mentioned prior arts is that the sputtering of the electrode portion is large and the consumption of mercury is fast, resulting in a short service life. Since a soft glass that matches the coefficient of thermal expansion is used, it is vulnerable to thermal shock, the glass bulb strength decreases, and the cathode drop voltage rises, making it impossible to reduce the power consumption of the cold cathode fluorescent lamp. There was a problem.

The second type has a large electrode sputtering and consumes mercury quickly, resulting in a short service life. Further, when the external lead wire is oxidized, the solderability is deteriorated and the cathode drop voltage is increased. Therefore, there is a problem that it is impossible to reduce the power consumption of the cold cathode fluorescent lamp.

The third type uses tungsten, and therefore hard glass having a high softening point is used to match the thermal expansion coefficient with that of tungsten, and it is difficult to form a glass bulb into a W shape or a U shape. There is also a problem that the solderability of the lead-in wire is deteriorated.

Therefore, in the present invention, in order to eliminate the problems of the above-mentioned conventional example, the electrodes constituting the mount are formed in a shape in which discharge is likely to occur, and the lead-in wire is made of hard glass at the sealing portion with the glass bulb. Using a metal that matches the coefficient of thermal expansion,
An object of the present invention is to provide a cold cathode fluorescent lamp which can further reduce power consumption, have a longer life, and can be made smaller by using a metal having good conductivity for the external conductor.

[0008]

In order to achieve the above object, the invention according to claim 1 of the present invention provides a mount comprising an electrode made of a cold cathode, a sealing lead-in wire and an external lead-in wire, In a cold cathode fluorescent lamp, a phosphor coating is formed on the inner surface, and the electrodes are sealed so that the electrodes are oppositely located at both ends inside a glass bulb in which a rare gas or the like is sealed.
The electrode is made of tungsten, the introduction wire for sealing is made of Kovar, and the introduction wire for external is made of Dumet.

In the invention according to claim 2 of the present invention, the shape of the electrode according to claim 1 is formed such that the thickness gradually decreases from the base portion connected to the sealing introduction wire to the inner end. It is characterized by

In the invention according to claim 3 of the present invention, in the electrode according to claim 2, the thickness of the inner end is 20% or less of the thickness of the base portion connected to the sealing lead-in wire. It is characterized by taste.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

1 to 3, the glass bulb 1 has an extremely small diameter of 4 mm or less, and a phosphor coating 2 is formed on the entire inner surface of the glass bulb 1. The glass bulb 1 is filled with a rare gas such as argon gas or xenon gas. The mount 3 is formed by connecting an electrode 5 made of a cold cathode to the inner end of the lead-in wire 4. Introductory line 4
Is formed by Kovar on the inner side to form the sealing introduction line 6, and on the outer side is formed by Dumet to form the external introduction line 7. The sealing introduction line 6 and the external introduction line 7 are It is formed by connecting linearly. The reason why the introduction wire 6 for sealing is made Kovar is that it is suitable as a sealing material because it has a thermal expansion coefficient close to that of hard glass. The reason why the external introduction wire 7 is made to be dumet is that the conductivity is good. The electrode 5 made of a cold cathode is made of tungsten, and its shape is gradually thinned from the base 8 toward the inner end 9. The thickness of the inner end 9 is preferably 20% or less of the thickness of the base 8. As described above, when the electrode 5 is formed into a sharp shape with a thin inner end, discharge is more likely to occur and the initial characteristics are improved.

[0013]

The present invention has a structure in which tungsten is used for the electrodes, Kovar is used for the lead-in wire for sealing, and Dumet is used for the external lead-in wire. Therefore, when manufacturing a cold cathode fluorescent lamp, soldering, sealing, glass Since valve molding can be performed without any inconvenience, workability can be improved, and the obtained product is highly reliable.

Since the sputtering of the electrode part is reduced,
The increase in the cathode drop voltage is also eliminated, and as a result, the initial characteristics are improved, and it is possible to further reduce the thickness of the glass bulb, so that it is possible to obtain a liquid crystal display device that can achieve low power consumption, downsizing, and long life. effective.

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view of a cold cathode fluorescent lamp according to an embodiment of the present invention.

FIG. 2 is a partially cutaway enlarged side view showing a state in which an electrode is sealed to a glass bulb.

FIG. 3 is an explanatory diagram showing a mount.

FIG. 4 is a partially cutaway enlarged side view showing a state in which electrodes are sealed on a glass bulb in a conventional cold cathode fluorescent lamp.

FIG. 5 is an explanatory view showing a mount in a conventional cold cathode fluorescent lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass bulb 2 Phosphor coating 3 Mount 5 Electrode 6 Sealing introduction line 7 External introduction line 8 Base 9 Inner end

Claims (3)

[Claims] 1. An electrode 5 is provided at an inner end of the introduction wire 6 for sealing,
5 are electrically connected to each other, and external introduction lines 7, 7 made of a metal different from the sealing introduction lines 6, 6 are integrally formed at outer ends of the sealing introduction lines 6, 6. Mount 3,
3, the electrodes 5 and 5 at the inner ends of the glass bulb 1 so as to airtightly introduce the sealing introduction lines 6 and 6 from the end wall of the glass bulb 1 having the phosphor coating 2 formed on the inner surface thereof. In the cold cathode fluorescent lamp sealed so as to have an opposite positional relationship, the electrode 5 is made of tungsten, the sealing introduction line 6 is made of Kovar, and the external introduction line 7 is made of Dumet. Characteristic cold cathode fluorescent lamp. 2. The electrode 5 according to claim 1, wherein the sealing lead-in wire 6
The cold cathode fluorescent lamp according to claim 1 or 2, wherein the cold cathode fluorescent lamp is formed so that the thickness gradually decreases from the base portion 8 connected to the inner end 9 side. 3. The coolness according to claim 2, wherein the thickness of the inner end 9 of the electrode 5 is 20% or less as compared with the thickness of the base 8 connected to the sealing lead-in wire 6. Cathode fluorescent lamp.