JP2003331726A - Manufacturing method of cold cathode discharge tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a cold cathode discharge tube in which a prescribed amount of mercury pellets filled in the glass bulb is diffused between a pair of main electrodes and sealed by preventing leakage of the mercury gas due to break of the glass bulb in the manufacturing process of the cold cathode discharge tube. <P>SOLUTION: An opening at one end of a cylindrical glass bulb 2 is sealed by bead glass 4a of a main electrode 3a at one end and the other main electrode 3b is inserted in a prescribed position in the glass bulb 2. And mercury pellet P is filled from the opening of the other end, and the inside of the glass bulb is exhausted and a rare gas is filled, and then, the opening at the other end is sealed. While the glass bulb 2 is rotated centered on an axis, the mercury pellet P is heated and vaporized through the glass bulb 2 and diffused between the pair of main electrodes 3a, 3b, and then, the vaporized mercury is filled between the pair of main electrodes 3a, 3b. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cold cathode discharge tube used as a backlight for OA equipment such as a personal computer, a word processor, and a liquid crystal television. 2. Description of the Related Art As shown in FIG. 1, a cold cathode discharge tube conventionally used as a backlight of OA equipment, a liquid crystal television, etc. is a cylindrical glass having a fluorescent film 1 formed on an inner peripheral surface thereof. A bulb 2 and a pair of rod-shaped main electrodes 3a, 3 arranged such that one ends thereof are opposed to each other in the glass bulb 2.
b and bead glasses 4 a, 4 attached around the outer circumference of the main electrodes 3 a, 3 b and sealing both ends of the glass bulb 2.
In the glass bulb 2, a rare gas composed of a mixed gas of argon and neon and a mercury gas filled therein are mainly used. The main electrode 3
a and 3b are bottomed cylindrical electrodes 5a and 5b, and electrodes 5a and 5b.
5b, which are formed of metal rods 6a and 6b each having a rod connected at one end to the bottom of the glass 5b.
a, 4b are attached around the outer periphery of the introduction metal bodies 6a, 6b. In order to manufacture this kind of cold cathode discharge tube, as shown in FIG. 3, one end opening of a glass bulb 2 having a fluorescent coating 1 formed on the inner peripheral surface and one main electrode 3a are attached. The bead glass 4a is welded, and one end opening of the glass bulb 2 is sealed. On the other hand, the other main electrode 3b to which the bead glass 4b is attached is inserted into the glass bulb 2 from the other end opening of the glass bulb 2, and the other main electrode 3b
Electrode 5b is positioned at a predetermined distance from the electrode 5a of one main electrode 3a, and the other main electrode is not completely sealed (gas can flow in and out) of the internal space of the glass bulb 2. A part of the bead glass 4b attached to 3b and a part of the glass bulb 2 are welded to position the other main electrode 3b. Then, the main electrode 3a is sealed in the end opening,
The mercury pellet P is inserted in the opening end of the glass bulb 2 having the main electrode 3b temporarily fixed to the other end opening, and the glass bulb 2 is placed in an exhaust sealing container (not shown). Next, by evacuating the interior of the glass bulb 2 between the pair of main electrodes 3a and 3b by evacuating the interior of the evacuated sealing container, the rare bulb described above is filled into the glass bulb 2 and the glass bulb is filled. 2 is melted and sealed, and the mercury pellet P
To form a mercury discharge chamber 9 in which Next, after taking out the glass bulb 2 from the exhaust sealing container, the outer periphery of the mercury discharge chamber 9 in which the charged mercury pellets P are located is heated by the high-frequency coil 7 to gasify the mercury pellets P. Gasified mercury (hereinafter, referred to as mercury gas) diffuses and flows between the pair of main electrodes 3a and 3b through between the bead glass 4b and the glass bulb 2. Then, the outer peripheral surface of the glass bulb 2 corresponding to the bead glass 4b of the other main electrode 3b is heated by the burner 8,
The glass bulb 2 and the bead glass 4b are welded to each other to form an inner space of the glass bulb 2 with a pair of main electrodes 3a, 3b.
And a rare gas and a mercury gas (hereinafter referred to as a sealing gas X) are sealed between the pair of main electrodes 3a and 3b. Then, the portion where the mercury discharge chamber 9 is formed in the glass bulb 2 is cut off from the welded portion between the glass bulb 2 and the bead glass 4b of the other main electrode 3b so as to maintain the sealed state of the enclosed gas X. The cold cathode discharge tube shown in FIG. 1 is completed. However, as described above, when the mercury discharge chamber 9 is heated by the high-frequency coil 7 in order to vaporize and diffuse the mercury pellets P, the gas in the mercury discharge chamber 9 has a smaller volume than the gas in the mercury discharge chamber 9. Since the heat conductivity of the mercury pellet P is high, the temperature of the mercury pellet P to be vaporized becomes high, and the glass bulb 2 forming the mercury discharge chamber 9 and the mercury pellet P
Heat concentrates on the abutting part. For this reason, when the diameter of the glass bulb 2 is small and the thickness of the glass bulb is thin recently, the contact portion between the glass bulb 2 and the mercury pellet P is locally melted and the hole is formed. H may become empty. Therefore, the vaporized mercury leaks from the hole H, and all of the mercury pellets P introduced into the glass bulb 2 may not be efficiently sealed between the pair of main electrodes 3a and 3b. have. In view of such circumstances, the present invention prevents the leakage of mercury gas in the process of manufacturing a cold cathode discharge tube, and efficiently transfers a predetermined amount of mercury pellets charged into a glass bulb to a pair of main electrodes. An object of the present invention is to provide a method for manufacturing a cold cathode discharge tube that can be diffused and sealed between the discharge tubes. [0008] In order to solve the above problems,
The method for manufacturing a cold cathode discharge tube according to the present invention comprises a pair of rod-shaped main electrodes to which a bead glass is attached around the outer periphery and is arranged at a predetermined interval in the axial direction, as described in claim 1, A method for manufacturing a cold cathode discharge tube in which an internal space of a cylindrical glass bulb is sealed and a predetermined amount of a rare gas and gasified mercury are sealed in the internal space, wherein a bead attached to one main electrode is provided. A first sealing step of sealing one end opening of the glass bulb with glass, and at a predetermined position in the glass bulb having a predetermined interval with respect to the one main electrode, the other main electrode with bead glass attached thereto. A loose insertion step of loosely inserting, and after the loose insertion step, a second sealing step of charging a mercury pellet into the glass bulb from the other end opening and sealing the other end opening of the claim, Mercury pellet while rotating around the center Heating and gasifying through a glass bulb, a diffusion step of diffusing gasified mercury between the pair of main electrodes via the other main electrode, and welding a glass bulb and bead glass of the other main electrode, And a sealing step of sealing gasified mercury between the pair of main electrodes. According to the method of manufacturing a cold cathode discharge tube having the above structure, when diffusing a mercury pellet between a pair of main electrodes,
Since the mercury pellet is heated via the glass bulb while rotating the glass bulb around the axis, when the mercury pellet is heated, the rotation of the glass bulb causes the mercury pellet to move on the inner peripheral surface of the glass bulb. By moving, the contact point of the glass bulb with the mercury pellet changes, and it is possible to prevent heat from being concentrated on the same point on the glass bulb. Therefore, it is possible to prevent a situation in which heat is concentrated on a specific place of the glass bulb and a hole is opened, so that it is possible to prevent mercury gas from leaking in a manufacturing process of the cold cathode discharge tube, and furthermore, it is possible to prevent the glass bulb from leaking. A predetermined amount of mercury pellets charged into the bulb can be efficiently diffused between the pair of main electrodes. Hereinafter, a cold cathode discharge tube according to an embodiment of the present invention will be described with reference to the drawings. The cold cathode discharge tube according to the present embodiment is shown in FIG.
As shown in FIG. 3, a cylindrical glass bulb 2 on which an inner peripheral surface fluorescent film 1 is formed, and a pair of rod-shaped main electrodes 3a, 3 arranged such that one ends thereof face each other in the glass bulb 2.
b and bead glasses 4 a, 4 attached around the outer circumference of the main electrodes 3 a, 3 b and sealing both ends of the glass bulb 2.
In the glass bulb 2, a rare gas composed of a mixed gas of argon and neon, and vaporized mercury are sealed. The main electrodes 3a and 3b are formed of cylindrical electrodes 5a and 5b having bottoms, and an introduced metal body 6a formed of a rod having one end connected to the center of the bottom of the electrodes 5a and 5b.
6b. The bead glass 4a, 4b is attached around the outer periphery of the introduced metal body 6a, 6b. In order to manufacture such a cold cathode discharge tube, FIG.
As shown in the figure, a pair of main electrodes 3a and 3b having spherical bead glasses 4a and 4b attached around the outer circumference of the above-described introduced metal bodies 6a and 6b, and a fluorescent coating 1 formed on the inner circumference, and both ends are opened A cylindrical glass bulb 2 in a state is prepared. The electrode 5a is a cylindrical glass bulb 2.
After inserting one main electrode 3a into one end opening of the glass bulb 2 so that the other end of the introduction metal body 6a is located inside the glass bulb 2 and then attached to the introduction metal body 6a. The bead glass 4a and the one end opening of the glass bulb 2 are heated and welded to each other so as to be airtight, thereby sealing the one end opening (first sealing step). Thereafter, the electrode 5b of the other main electrode 3b is
One main electrode 3 sealing one end opening of the glass bulb 2
The other main electrode 3b is inserted into the glass bulb 2 from the other end opening of the glass bulb 2 so as to be opposed to the electrode 5a of the glass bulb 2 and at a predetermined distance from the electrode 5a of the one main electrode 3a. Play insertion (play insertion process). Then, a part of the outer peripheral surface of the glass bulb 2 corresponding to the bead glass 4b attached to the other main electrode 3b is heated by the burner 8 so as to form a gap through which gas can flow in and out. And a part of the bead glass 4b attached to the other main electrode 3b are welded to form the other main electrode 3b.
(Bead glass 4b) is temporarily fixed. In this state, the mercury pellet P is inserted into the other opening on the side where the electrode 3b of the glass bulb is temporarily fixed, and the glass bulb 2 is placed in a closed container (not shown) for exhaust sealing. Then, by exhausting the inside of the closed vessel, the other end of the glass electrode 2 is opened from the other end opening of the glass bulb 2 via the portion where the bead glass 4b of the other main electrode 3b is temporarily fixed. Is discharged, and this state is maintained, and a rare gas composed of a mixed gas of argon and neon is filled between the pair of main electrodes 3a and 3b. Then, while maintaining the state in which the rare gas is filled in the glass bulb 2, the other end opening of the glass bulb 2 is melted and sealed, and the bead glass 4b and the other end opening are sealed. The part forms a mercury discharge chamber 9 in which the mercury pellet P is present (second sealing step). Next, the glass bulb 2 is taken out of the sealed container, and thereafter, the outer peripheral surface of the glass bulb 2 forming the mercury emission chamber 9 is heated by the high-frequency coil 7 while rotating the glass bulb 2 around the axis. The mercury pellet P in the gas 9 is gasified to be in a diffusion state, and mercury (mercury gas) gasified through a portion where the bead glass 4b is temporarily fixed is used as a pair of main electrodes 3a,
Inflow (diffusion) between 3b (diffusion step). In order to surely diffuse the mercury gas between the pair of main electrodes 3a and 3b in the glass bulb 2, the glass bulb corresponding to the portion where the bead glass 4b of the other main electrode 3b is temporarily fixed after a predetermined time has elapsed. 2 is heated by a burner 8, and the bead glass 4b and the glass bulb 2 are welded so that the gap formed between the bead glass 4b and the glass bulb 2 is completely closed. A rare gas and a mercury gas (hereinafter, referred to as a sealing gas X) are sealed between 3a and 3b (sealing step). Finally, the glass bulb 2 located on the mercury discharge chamber 9 side, which is not necessary as a discharge tube, is cut off to obtain the structure shown in FIG.
Is completed. As described above, mercury gas is supplied to the glass bulb 2
When the mercury pellet P is vaporized so as to be diffused between the pair of main electrodes 3a and 3b, the glass bulb 2 is rotated around the axis while the mercury discharge chamber 9 in which the mercury pellet P is located Therefore, even if the heat generated by the heating of the high-frequency coil 7 is transmitted to the mercury pellet P, the rotation of the glass bulb 2 causes the mercury pellet P to slide on the inner peripheral surface of the glass bulb 2 or to be rolled. The pellet P and the inner peripheral surface of the mercury discharge chamber 9 move relatively to prevent heat transmitted to the mercury pellet P from being concentrated on a part of the glass bulb 2 forming the mercury discharge chamber 9. Can be. Accordingly, it is possible to prevent a situation in which the glass bulb 2 forming the mercury emission chamber 9 is locally melted and a hole is opened, so that the mercury gas is prevented from leaking from the inside of the mercury emission chamber 9 (glass bulb 2). Between the pair of main electrodes 3a,
All of the predetermined amount of mercury pellets P necessary for sealing in 3b can be efficiently gasified and flown (diffused) between the pair of main electrodes 3a, 3b in the glass bulb 2. The method for manufacturing a cold cathode discharge tube according to the present invention comprises:
It is needless to say that the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention. In this embodiment, after one end of the opening of the glass bulb 2 is sealed with one main electrode 3a (first sealing step), the other main electrode 3b is loosely inserted into the glass bulb 2 (free sealing). In the insertion step), in the loose insertion of the other main electrode 3b into the glass bulb 2 (the loose insertion step), the opening of one end of the glass bulb 2 is necessarily sealed with the one main electrode 3a (bead glass 4a) (first insertion). It is not necessary to perform the operation after the sealing step), and after the other main electrode 3b is loosely inserted into the glass bulb 2 (the loose insertion step), the glass electrode 2 is connected to the one main electrode 3a.
May be sealed (first sealing step). In this case, one end opening of the glass bulb 2 is connected to one main electrode 3a.
Of course, the other main electrode 3b is loosely inserted into a predetermined position in the glass bulb 2 at a position having a predetermined distance from the one main electrode 3a when sealing is performed. As described above, according to the present invention, in the step of diffusing mercury pellets between a pair of main electrodes in the process of manufacturing a cold cathode discharge tube (diffusion step), a glass bulb is rotated around an axis. The mercury pellet was heated via the glass bulb while rotating the glass bulb, so that the rotation of the glass bulb allowed the relative movement between the mercury pellet and the inner peripheral surface of the glass bulb. It is possible to prevent contact with the same part of the valve.
Therefore, since the heat transmitted to the mercury pellet is not concentrated on a specific part in the glass bulb, and a situation such as a hole being opened in the glass bulb can be prevented, the manufacturing process of the cold cathode discharge tube can be prevented. In addition, it is possible to prevent the leakage of the mercury gas at a time, and to efficiently diffuse a predetermined amount of the mercury pellets charged into the glass bulb between the pair of main electrodes and seal the same.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall sectional view of a cold cathode discharge tube according to one embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining a method of manufacturing the cold cathode discharge tube according to the embodiment. FIG. 3 is a state diagram showing a state in which a glass bulb has a hole when a conventional cold cathode discharge tube is manufactured. [Description of References] 1 Fluorescent coating 2 Glass bulb 3a Main electrode 3b Main electrode 4a Bead glass 4b Bead glass 5a Electrode 5b Electrode 6a Introduced metal body 6b Introduced metal body 7 High-frequency coil 8 Burner 9 Mercury discharge chamber P Mercury pellet X Filled gas (rare gas and mercury gas)

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Kazuo Nishiyama             2-9-95 Nagara Higashi 2-chome, Kita-ku, Osaka-shi, Osaka             West Electric Co., Ltd. F term (reference) 5C012 RR03 RR05

Claims (1)

Claims: 1. A pair of rod-shaped main electrodes having bead glass attached around an outer periphery thereof and arranged at a predetermined interval in an axial direction, wherein an inner space of a cylindrical glass bulb is formed. A method for manufacturing a cold cathode discharge tube in which a predetermined amount of a rare gas and gasified mercury are sealed in the internal space, wherein one end of a glass bulb is opened with bead glass attached to one main electrode. A first sealing step of sealing the portion, a loose insertion step of loosely inserting the other main electrode to which the bead glass is attached, at a predetermined position in the glass bulb having a predetermined interval with respect to the one main electrode, After this play insertion step, a mercury pellet is charged into the glass bulb from the other end opening, the internal space of the glass bulb is evacuated, the rare gas is sealed, and then the second end opening is sealed. Sealing process and glass bulb While rotating around the center, the mercury pellet is heated and gasified through a glass bulb, and a diffusion step of diffusing the gasified mercury between the pair of main electrodes via the other main electrode, A process of welding a bulb and bead glass of the other main electrode, and sealing gasified mercury between the pair of main electrodes.