JP2001266746A - Manufacturing method for cold-cathode fluorescent tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of poor productivity in the past where manufacturing method for cold-cathode fluorescent tube is required to be attached with a suction/exhaust unit while heating, because it is necessary to evacuate the glass tube, heat electron-emitting substance to be activated in vacuum or in inert gas, and evacuate the active impurity gas developed. SOLUTION: A getter substance is provided in a glass tube and activated by heating the electron-emitting substance, after mercury and sealing gas are filled therein, and then sealing the glass tube. As a result, the need for attaching to the suction/exhaustion unit is eliminated and will not lower production yield, with the time for heating being sufficient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cold cathode fluorescent tube used as a light source of an illuminating device for illuminating a liquid crystal display device for a computer or the like with transmitted light from the back.

[0002]

2. Description of the Related Art FIGS. 9 to 12 show an example of a conventional method of manufacturing a cold cathode fluorescent tube 90 of this type, and FIG. 9 is a process chart for applying an electron-emitting substance 64 to the surface of an electrode. ,
An electrode substrate 60 made of nickel or the like is connected to a leading end of a lead wire 61 such as a dumet wire, and a glass ball (bead) is held in the middle of the lead wire 61. A slurry of an electron-emitting substance 64 such as barium oxide, strontium oxide, calcium oxide, or a mixed oxide of an alkaline earth metal mainly composed of these is uniformly applied to the surface of the electrode substrate 60, and the surface of the electrode substrate 60 is exposed to electrons. A coating film of the radioactive substance 64 is formed. The electrode manufactured in this manner is referred to as a coating electrode 50. As shown in FIG. 9, the coating film of the electron-emitting substance is
It can be manufactured by an appropriate method such as a so-called dipping method or a spin coating method, which is immersed in a slurry of the electron-emitting substance 64 in the container 63. In this way, a pair of coating electrodes 50 each having the glass ball 62 and the lead wire 61 are produced.

[0003] Next, as shown in FIG.
A glass tube 65 having a cylindrical shape or the like, in which a phosphor film 69 is provided at a predetermined position where is formed, is prepared, and the glass ball 62 is placed on the narrowed portion 66A using one of the pair of coating electrodes 50 and introduced. The wire 61 and the electrode substrate 60 are set at predetermined positions in the glass tube 65, and the vicinity of the narrowed portion 66 </ b> A and the glass ball 62 is held by the support 70 as shown in FIG.
By heating at 1 or the like, the glass tube 65 and the glass ball 62 are melted and welded to each other to form a welded portion 67A for sealing one end of the glass tube 65.

Then, as shown in FIG. 12, the other of the pair of coating electrodes 50 is used for another narrowed portion 66B formed on a part of the glass tube 65 remote from the welded portion 67A. The glass ball 62 is placed on the glass tube 66B, the lead wire 61 and the electrode substrate 60 are set at predetermined positions in the glass tube 65, and the opening end 68 of the glass tube 65 on the narrowed portion 66B side is sucked and exhausted by the air suction and exhaust device 80. 86. The suction / exhaust device 80 moves the glass tube 65 to the suction / exhaust head 86.
A vacuum pump 81 for sucking air into the glass tube 65 to evacuate the glass tube 65, a gas supply source 82 for injecting a predetermined gas such as neon or argon into the glass tube 65, and a switching valve for switching between intake and exhaust 83, an exhaust solenoid valve 84, and an intake solenoid valve 85.

Next, in a state where a glass tube 65 having a pair of coating electrodes 50 is connected to a suction / exhaust head 86,
The exhaust passage is opened by the exhaust solenoid valve 84 and the switching valve 83, and the air in the glass tube 65 is exhausted by the operation of the vacuum pump 81 to make it vacuum. During this evacuation step, the coating electrode 50 is heated from outside the glass tube 65 by a heating source 87 as a heating means.
Heat at a temperature of 00 ° C or higher. This heating method may be laser heating in addition to high frequency heating. As for the heating conditions, for example, when the heating temperature is 1200 ° C., the heating time is 60 seconds or less. The heating activates the electron-emitting substance 64 provided on the electrode substrate 60 to lower the lighting voltage of the cold-cathode fluorescent tube 90, reduce the heat generation temperature of the electrode substrate 60, and prevent the electrode substrate 60 from evaporating. Thus, the so-called emitter function is exhibited.

Thereafter, the switching valve 83 and the intake solenoid valve 85
A small amount of mercury is sealed in the glass tube 65 together with a predetermined gas such as argon from the gas supply source 82. Further, after that, the glass ball 62 and the vicinity of the squeezed portion 66B are heated by the gas burner 71 and the like, and the glass tube 65 and the glass ball 62 are melted and welded to each other. Form 67B. After such a step, the cold cathode fluorescent tube 90 is obtained by removing unnecessary portions outside the welded portion of the glass tube.

The mercury is supplied to the cold cathode fluorescent tube 9 described above.
In some cases, a mercury alloy material is provided on the coating electrode 50 in the area 0. By providing a non-evaporable getter material in the cold cathode fluorescent tube 90,
In the above-described vacuum evacuation step, the heating step is omitted, and after the cold cathode fluorescent tube 90 is formed, the same high-frequency heating as described above is performed to activate the electron-emitting substance 64,
There is also a method in which the impure gas generated at this time is absorbed by the getter material.

[0008]

However, in the conventional manufacturing method, a step of heating the electron-emitting substance 64 in a vacuum state and further exhausting the generated impurity gas is required. Because of the long length, the efficiency in the production line is poor. For this reason, the conditions such as the heating time are greatly restricted, the activation conditions are strict, and the production yield may be reduced.

When a mercury alloy material for supplying mercury is provided in the cold cathode fluorescent tube 90, the heating step for activating the electron-emitting substance 64 provided on the electrode substrate 60 is performed in the step of heating. The mercury alloy material also evaporates and scatters at the same time, and the mercury is released to the outside in the exhaust process, so that the amount of mercury required when the cold cathode fluorescent tube 90 is completed may not be secured. became.

In the case where the cold cathode fluorescent tube 90 has a getter material, the getter material is sputtered by discharge when the cold cathode discharge tube 90 is used, so that the adsorbed gas is released and the cold cathode fluorescent tube 90 is discharged. The luminous efficiency of the fluorescent tube 90 has been reduced.

In view of the above problems, it is an object of the present invention to provide a cold cathode discharge tube 90 suitable for mass production without lowering the production yield, and to provide a manufacturing method therefor. is there.

[0012]

According to the present invention, there is provided a method for manufacturing a cold cathode fluorescent tube having an electrode having an electron-emitting substance which needs to be heated for activation as a specific means for solving the above-mentioned problems. A step of preparing a glass tube in which a main body to be a cold-cathode fluorescent tube and an exhaust pipe are partitioned by a throttle unit; a step of providing a phosphor at a predetermined position in the main body of the glass tube; A step of providing and sealing an electrode having an electron-emitting substance, a step of arranging an electrode having an electron-emitting substance in the throttle section, and a getter material for adsorbing active impurity gas in a discharge space on the exhaust pipe side. And a step of filling a predetermined filling gas and mercury in the glass tube; a step of sealing and sealing the exhaust pipe side opening; and after the step of sealing, heating the electrode and preparing the electrode. A step of activating the electron-emitting substance that has been cooled, and thereafter, a step of welding and sealing the glass tube and the electrode of the throttle section, and a step of separating the exhaust pipe. An object of the present invention is to solve the problem by providing a method for manufacturing a cathode fluorescent tube.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 to 8 show a method of manufacturing a cold cathode fluorescent tube 10 according to the present invention in the order of steps. First, as shown in FIG. 1, for example, the outer diameter is set to about 3 mm, and a part of the first squeezed portion 1 a is formed by squeezing a part thereof. A glass tube 1 partitioned into an exhaust pipe 1c is prepared. At this time, a phosphor is applied to the inner surface of the main body 1b of the glass tube 1 to form the phosphor film 2.

Next, as shown in FIG. 2, a coating electrode 3 provided with an electron emitting material 3d and an electrode substrate 3c connected to a lead-in line 3b is provided in an opening 1d on the main body side of the glass tube 1.
Attach and seal. In the present embodiment, a second aperture 1f is provided on the main body 1b of the glass tube 1, and a glass ball 3a is provided in the middle of the introduction line 3b of the coating electrode 3, as in the conventional case. The first sealing portion 1g is located at the narrowed portion 1f and sealed by welding with a gas burner 4 or the like.

Next, as shown in FIG.
The coating electrode 5 similar to the above is disposed on the side of the exhaust pipe 1c. At this time, the opening diameter of the first aperture portion 1a is
Is smaller than the glass ball 5a, and the glass ball 5a can be installed. However, since the shape does not match, the glass ball 5a does not completely cover the opening, and the gas can enter and exit. is there. As an example, the glass ball 5a may be a square or the like, and the position may be fixed by being in contact with the first aperture portion 1a at the vertex. In the drawing, the glass tube 1 is shown in a horizontal direction, but is actually arranged such that the exhaust pipe side opening 1e is at the top.

Next, a getter material 6d made of a zinc-aluminum alloy or the like which adsorbs an active impurity gas is provided, and a glass plate 6c connected to the lead wire 6b is provided. Prepare the one with the ball 6a,
As shown in FIG. 4, the exhaust pipe side opening 1e of the glass tube 1 is provided.
The opening 1e of the glass tube 1 on the exhaust pipe side
A third throttle portion 1h is provided in the vicinity, and the stem 6 with the getter material is provided.
Place. The stem 6 with the getter material is also used as the coating electrode 5.
Similarly to the above, the shape of the glass ball 6a and the shape of the opening of the third aperture portion 1h do not coincide with each other. In this state, a suction / exhaust device (not shown) is attached to the exhaust pipe side opening 1e, and a filling gas 9 such as mercury and a mixed gas of neon and argon necessary for the cold cathode fluorescent tube 10 is filled. Note that mercury is applied to the electrode substrate 3
A mercury alloy material may be provided for c and 5c, and the glass tube 1 may be supplied by heating after sealing. After the gas 9 is filled, the third throttle 1
h is heated by the gas burner 4 and the stem 6 with the getter material is heated.
Is melted together with the glass ball 6a to form the second sealing portion 1i, and the inside of the glass tube 1 is sealed.

Next, as shown in FIG.
In order to activate the electron-emitting substances 3d and 5d provided on the 5, the high-frequency coil 7 and the like are placed on the side of the coating electrodes 3 and 5 to heat. At this time, an active impurity gas is generated, but the getter material 6d provided at the end of the exhaust pipe 1c is formed.
Thus, only a predetermined gas required for electric discharge is present in the glass tube 1.

Thereafter, as shown in FIG.
Is heated by a gas burner 4 or the like, and the glass ball 5a of the coating electrode 5 disposed here is melted and welded to the glass tube 1 to form a third sealing portion 1j. Then, as shown in FIG. 7, by chipping off the exhaust pipe 1c side of the third sealing portion 1j, the cold cathode fluorescent tube 10 shown in FIG. 8 is completed.

In the present embodiment, the sealing of the opening 1d on the main body side and the opening 1e on the exhaust side is performed by the first diaphragm 1a.
Was performed with an electrode using the same glass ball as
The method is not limited to this, and may be performed by another method. However, since the first aperture portion 1a needs to be sealed with an electrode using this glass ball, the same method can be used in other places to reduce the number of types of parts and to simplify the operation. .

The electrode substrates 3c, 5c of the coating electrodes 3, 5
The shape of the plate may be any of plate, rod, tube and the like, but is not limited thereto.
By providing d and 5d and providing a mercury alloy material on the outer surface, it is possible to reduce spattering of the electron-emitting substances 3d and 5d during discharge.

Furthermore, the getter material-added stem 6 is not limited to the one in this embodiment, and the getter material 6d exists in the exhaust pipe 1c, and the exhaust pipe side opening 1e is sealed. The glass ball 6a, the lead wire 6b, and the metal plate 6c are not necessarily required. or,
The sealing is not performed by welding the glass tube 1 and the glass ball 6a, but may be performed by providing a rubber cap and sealing as long as it can be airtight. However, according to the method of the present embodiment, the sealing can be performed in the same manner as the other openings, and the heating of the getter material is performed by the high-frequency coil similarly to the heating of the electron-emitting substance. Therefore, the manufacturing can be simplified.

The operation and effect of the above manufacturing method will be described. First, a step of exhausting the inside of the glass tube 1 for activating the electron-emitting substances 3d and 5d provided on the coating electrodes 3 and 5 becomes unnecessary. The number of processes is reduced. In addition, since the evacuation step is unnecessary, when heating the electron-emitting substances 3d and 5d, there is no need to install the glass tube 1 in the intake / exhaust device, so that heating can be handled as a separate step. The heating time of the substances 3d and 5d is made sufficiently long,
The activation condition can be satisfied. In this case, even if the heating time is set to be sufficiently long, the process can be performed in a step different from that of the production line for the cold cathode fluorescent tubes, so that the production yield is not reduced. Further, mounting the high-frequency coil on the intake / exhaust device requires a great deal of cost, and being able to handle it in a separate process leads to simplification of the manufacturing apparatus.

The active impurity gas generated at the time of heating is adsorbed by the getter material 6d, and the getter material 6d does not exist in the cold cathode fluorescent tube 10 after the gas is adsorbed. 6d is not sputtered and active impurity gas is not released. And even when the electrode contains a mercury alloy, the electron-emitting substance 3d, 5d
Evaporates at the same time as heating, and is present in the glass tube 1. However, since the gas is not exhausted, a sufficient amount can be obtained.

[0024]

According to the present invention, the electron-emitting material provided on the electrode is heated and activated in a closed space having mercury and a predetermined gas filling and a getter material necessary for a cold cathode fluorescent tube. There is no need for air intake and exhaust, and there is no need for heating while attached to the air intake and exhaust device. Therefore, heating can be performed in a step different from that of the cold cathode fluorescent tube production line, and the heating conditions can be made sufficient, and the yield of the production line does not decrease. In addition, there is no need to incorporate a special heating device such as a high-frequency coil into the production line, and a conventional device can be used as it is, without complicating the production device.

Further, since there is no evacuation step after heating,
When mercury is supplied by a mercury alloy material, a sufficient amount can be maintained in the cold cathode fluorescent tube even if mercury is released when the electron-emitting substance is heated. Since the getter material is discarded when the cold cathode fluorescent tube is completed and is not in the discharge space, the getter material is sputtered at the time of discharge and does not release the adsorbed impurity gas. As described above, the present invention is excellent in mass productivity.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a glass tube preparing step of a method for manufacturing a discharge tube according to the present invention.

FIG. 2 is an explanatory view showing a sealing step of a glass tube body side opening.

FIG. 3 is an explanatory view showing a process of arranging a coating electrode on a first aperture portion of the glass tube.

FIG. 4 is an explanatory view showing a sealing step of a glass tube exhaust pipe side opening.

FIG. 5 is an explanatory view showing a step of heating an electron emitting substance.

FIG. 6 is an explanatory view showing a step of sealing the first throttle portion in the same manner.

FIG. 7 is an explanatory view showing a step of cutting the main body of the glass tube and the exhaust pipe.

FIG. 8 is an explanatory view showing a completed state of the discharge tube.

FIG. 9 is an explanatory view showing a step of manufacturing a coated electrode in a conventional manufacturing method.

FIG. 10 is an explanatory view showing a process of arranging an end portion of a conventional glass tube and a coating electrode.

FIG. 11 is an explanatory view showing a sealing step of an end portion of a conventional glass tube.

FIG. 12 is an explanatory view showing a state in which a conventional glass tube is attached to a suction and exhaust device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Glass tube 1a ... First throttle part 1b ... Main body 1c ... Exhaust pipe 1d ... Main body side opening part 1e ... Exhaust pipe side opening part 1f ... Second throttle part 1g ... First sealing Part 1h Third diaphragm part 1i Second sealing part 1j Third sealing part 2 Phosphor film 3, 5 Coating electrode 3a, 5a Glass ball 3b, 5b Introduction Wire 3c, 5c Electrode substrate 3d, 5d Electron-emitting substance 4 Gas burner 6 Stem with getter material 6a Glass ball 6b Lead wire 6c Metal plate 6d Getter material 7 High frequency coil 8 Cutter 9 Filled gas 10 Cold cathode fluorescent tube

Claims (2)

[Claims] 1. A method of manufacturing a cold cathode fluorescent tube having an electrode provided with an electron-emitting substance which needs to be heated for activation, wherein a glass body in which a cold cathode fluorescent tube and an exhaust pipe are separated by a throttle unit. A step of preparing a tube, a step of providing a fluorescent substance at a predetermined position of the main body of the glass tube, a step of providing and sealing an electrode including an electron-emitting substance in an opening on the side of the main body, A step of disposing an electrode including a radioactive substance, a step of disposing a getter material that adsorbs an active impurity gas in a discharge space on the exhaust pipe side, and a step of enclosing a predetermined sealing gas and mercury in the glass tube, A step of sealing and closing the exhaust pipe side opening, and after the step of sealing, heating the electrode and activating an electron-emitting substance provided in the electrode; A method for manufacturing a cold cathode fluorescent tube, comprising at least a step of welding and sealing a tube and the electrode, and a step of separating the exhaust pipe. 2. The method according to claim 1, wherein the mercury is obtained by providing a mercury alloy material on the electrode.