JP2001155632A - Method for producing cold cathode fluorescence discharge tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a cold cathode fluorescence discharge tube which can form easily a fluorescent film of uniform and thick film thickness. SOLUTION: The method for producing a cold cathode fluorescence discharge tube comprises introducing a fluorescent film forming solvent into an internal part of a glass tube 20 of the cold cathode fluorescence discharge tube and rotating the glass tube 20 in a high speed using a length direction of the tube as the rotation axis. The rotation speed is set to at least 5,000 cycles per minute or more, preferably at least 10,000 cycles per minute. A strong centrifugal force is applied to the internal fluorescent film forming solvent of the glass tube 20 by the high speed rotation, and the fluorescent film forming solvent 32 having a high density of a fluorescence material can be formed near an internal wall of the glass tube 20. A fluorescent film can be formed from the fluorescent film forming solvent 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a cold cathode fluorescent lamp, and more particularly to a method for manufacturing a cold cathode fluorescent tube for forming a fluorescent film on the inner wall of a thin glass tube.

[0002]

2. Description of the Related Art An LCD monitor connected to a computer,
A backlight system is widely used in liquid crystal televisions and the like, and a cold cathode fluorescent discharge tube is generally used as a light source of the backlight system. In the cold cathode fluorescent discharge tubes for such applications, it is required to obtain uniform light emission intensity and uniform light emission color, and the demand for thinning the cold cathode fluorescent discharge tubes is increasing. In other words, OA equipment and AV equipment have been reduced in size and thickness due to the progress of the information communication era and the increase in mobile use, and correspondingly, the size and thickness of cold cathode fluorescent discharge tubes as light sources for LCD monitors and the like have been reduced. Is required. Further, in order to improve the light use efficiency when light emitted from the cold cathode fluorescent discharge tube passes through the backlight, it is important to make the discharge tube narrower.

As is well known, a cold cathode fluorescent discharge tube has a thin fluorescent film formed on the inner wall of a glass tube, and converts ultraviolet radiation from mercury vapor sealed inside the glass tube into visible light by the fluorescent film. . As a method of forming a fluorescent film on the inner wall of the glass tube, a method is generally used in which the fluorescent material is sucked from one opening of the glass tube and attached to the inner wall of the glass tube while the glass tube is upright. .

That is, first, a glass tube having both ends opened is prepared, and this glass tube is placed upright with its lower end opening immersed in a fluorescent film forming solvent. Next, suction is performed from the opening at the upper end of the glass tube, and the internal pressure of the glass tube is reduced to negative pressure, so that the fluorescent film forming solvent is sucked into the glass tube and adheres to the inner wall of the glass tube. Let it. Subsequently, after the negative pressure is released and the excess fluorescent film forming solvent is discharged from the opening at the lower end of the glass tube, a drying gas is poured into the glass tube and contained in the fluorescent film forming solvent attached to the inner wall of the glass tube. The solvent is evaporated. Finally, by subjecting the glass tube to a heat treatment, the fluorescent material can be baked on the inner wall of the glass tube to form a fluorescent film.

[0005]

Although the above-mentioned method for manufacturing a cold cathode fluorescent discharge tube has features that the process can be relatively easily automated and excellent in mass productivity, the following points are taken into consideration. Did not.

[0006] As a fluorescent film forming solvent, a mixture of a total of three components of a solvent, a binder and a fluorescent material is generally used. Specifically, an organic solvent such as nitrocellulose or ethylcellulose is used as the solvent, and a low melting glass powder is used as the binder. The solvent contained in this kind of fluorescent film forming solvent is excellent in that drying can be easily performed, handling is easy, and the like.

However, in the above-described method for manufacturing a cold cathode fluorescent discharge tube, the solvent sucked into the glass tube is discharged in a relatively short time, which contributes to the formation of a fluorescent film. The only fluorescent material that can be absorbed is the fluorescent material that is sucked in the vicinity of the inner wall of the glass tube and can adhere to the inner wall. In order to increase the thickness of the fluorescent film, it is necessary to increase the viscosity of the fluorescent film forming solvent considerably. However, when the viscosity of the fluorescent film forming solvent is increased, it becomes difficult to suck the fluorescent film forming solvent into the inside of the glass tube. In particular, in a glass thin tube having an inner diameter of 1.5 mm or less, it becomes difficult to satisfactorily suck the fluorescent film forming solvent into the glass thin tube and to discharge the fluorescent film forming solvent from the glass thin tube. A fluorescent film cannot be formed with a uniform thickness and with a high yield. For this reason, in a cold cathode fluorescent discharge tube, since a fluorescent film cannot be formed with a sufficient film thickness, the intensity of the fluorescent film with respect to ultraviolet irradiation and sputtering is reduced, and the reliability that a high luminance can be stably obtained for a long period of time is reduced. A high cold cathode fluorescent discharge tube could not be realized.

In the above-mentioned glass thin tube, if the viscosity of the solvent for forming the fluorescent film becomes high, it becomes difficult to automate the process of forming the fluorescent film, so that not only the productivity of the cold cathode fluorescent discharge tube is lowered, but also the production cost and product cost. There was a problem that would increase.

The present invention has been made to solve the above problems. Accordingly, an object of the present invention is to provide a method for manufacturing a cold cathode fluorescent discharge tube capable of easily forming a fluorescent film having a uniform thickness and a large thickness.

It is a further object of the present invention to provide a method of manufacturing a cold cathode fluorescent lamp capable of stably obtaining high luminance over a long period of time and improving reliability.

It is a further object of the present invention to provide a method for manufacturing a cold cathode fluorescent discharge tube capable of improving productivity.

It is a further object of the present invention to provide a method of manufacturing a cold cathode fluorescent lamp capable of achieving the above object even with a glass tube having an inner diameter of 1.5 mm or less. In particular, an object of the present invention is to provide a method of manufacturing a cold cathode fluorescent discharge tube capable of realizing miniaturization of devices such as a liquid crystal monitor and a liquid crystal television.

[0013]

In order to solve the above-mentioned problems, a feature of the present invention is to introduce a fluorescent film forming solvent into a glass tube having openings at both ends through at least one of the openings. Rotating the glass tube with the tube length direction as a rotation axis, thereby adhering a fluorescent film forming solvent to the inner wall of the glass tube, and forming a fluorescent film from the fluorescent film forming solvent. It is a method of manufacturing. Here, it is preferable that the glass tube is rotated at 5000 cycles or more per minute, and the fluorescent film forming solvent is attached to the inner wall of the glass tube by centrifugal force. More preferably, the glass tube is rotated at 10,000 cycles or more per minute, and the solvent for forming the fluorescent film is attached to the inner wall of the glass tube by centrifugal force. In particular, the method of manufacturing a cold cathode fluorescent discharge tube according to the present invention is characterized in that the inside diameter of the glass tube is 1.5
This method is suitable for forming a fluorescent film on the inner wall of the glass tube at a thickness of less than 1 mm. The fluorescent film forming solvent preferably contains at least a solvent, a binder and a fluorescent material, and by rotating the glass tube to attach the fluorescent material to the inner wall of the glass tube with the binder, and thereafter removing the solvent. Preferably, a fluorescent material is formed on the inner wall of the glass tube. Further, the step of introducing the fluorescent film forming solvent is preferably a step of immersing one opening of the glass tube in the fluorescent film forming solvent and sucking the fluorescent film forming solvent from the other opening of the glass tube.

In a method of manufacturing a cold cathode fluorescent discharge tube according to a feature of the present invention, a fluorescent film forming solvent is introduced into a glass tube, and the glass tube is rotated to generate centrifugal force. Is pressed strongly against the inner wall of the glass tube. And the density of the fluorescent material contained in the fluorescent film forming solvent near the inner wall of the glass tube is increased. Therefore, a fluorescent film having a uniform thickness and a large thickness can be easily formed on the inner wall of the glass tube. Therefore, since a fluorescent film having high strength against ultraviolet irradiation and sputtering can be formed, high brightness can be stably obtained over a long period of time, and a highly reliable cold cathode fluorescent discharge tube can be manufactured. Further, the viscosity of the fluorescent film forming solvent can be reduced, and the fluorescent film forming solvent can be easily introduced into the inside of the glass tube. In particular, even in a glass tube having an inner diameter of 1.5 mm or less, the solvent for forming a fluorescent film can be easily sucked into the glass tube. Therefore, since the process of forming the fluorescent film can be automated and the cold cathode fluorescent lamp can be mass-produced, the production cost and product cost of the cold cathode fluorescent tube can be reduced.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a sectional structural view of the cold cathode fluorescent discharge tube according to the embodiment of the present invention. As shown in FIG. 2, a cold cathode fluorescent discharge tube 1 includes a glass tube 2 sealed at both ends and having an airtight space inside, a fluorescent film 3 formed on the inner wall of the glass tube 2, and a glass tube 2. , The discharge electrode 4A and the electrode terminal 5A at the left end, the discharge electrode 4B and the electrode terminal 5B at the right end of the glass tube 2, and the discharge gas 6 sealed in the hermetic space of the glass tube 2. It is provided with.

The glass tube 2 is formed of an elongated tubular thin tube. In the embodiment of the present invention, the glass tube 2 is
For example, outer diameter 1.9mm, inner diameter 1.5mm, pipe length 500m
m.

The fluorescent film 3 on the inner wall of the glass tube 2 emits visible light when irradiated with ultraviolet rays generated by electric discharge. The discharge gas 6 is sealed to assist lighting of the cold cathode fluorescent discharge tube 1. This discharge gas 6
For example, a rare gas such as argon (Ar) gas or xenon (Xe) gas can be used practically, and the pressure inside the glass tube 2 is set to about 5.3 kPa to 13 kPa. In addition, inside the glass tube 2, a required fixed amount of mercury (mercury particles) for generating mercury discharge is sealed together with the discharge gas 6.

In the embodiment of the present invention, each of the discharge electrodes 4A and 4B arranged in a pair at both ends inside the glass tube 2 is formed in a cylindrical shape, and is made of an electrode material such as nickel (Ni). It is formed with. Although the respective electrode shapes of the pair of discharge electrodes 4A and 4B are not particularly limited, various shapes such as a dish shape, a bar shape, and a wire shape can be adopted.

One end of the electrode terminal 5A is electrically connected to the discharge electrode 4A, and the other end is led out of the glass tube 2. Similarly, one end of the electrode terminal 5B is electrically connected to the discharge electrode 4B, and the other end is led out of the glass tube 2. Each of the electrode terminals 5A and 5B is formed of a metal material having good electric conductivity such as nickel, for example, and is provided between the electrode terminal 5A and the discharge electrode 4A and between the electrode terminal 5B and the discharge electrode 4B. Both are joined, for example, by fusion bonding.

Next, a method of manufacturing the cold cathode fluorescent discharge tube 1 will be described. FIGS. 1, 3 to 8 are process sectional views of a cold cathode fluorescent discharge tube according to an embodiment of the present invention.

(1) First, as shown in FIG. 3, a first opening 21 is provided at one end on the left side, and a second opening 21 is provided at the other end on the right side.
An elongated cylindrical glass tube 20 having an opening 22 is prepared. The glass tube 20 is obtained by cutting a long glass thin tube having the above-mentioned outer diameter and inner diameter at an appropriate tube length by a known glass cutting technique. At this stage, the fluorescent film 3 has not been formed on the inner wall of the glass tube 20.

(2) Next, the glass tube 20 is held upright with the first opening 21 of the glass tube 20 facing downward and the second opening 22 facing upward. The first opening 21 is filled with the fluorescent film forming solvent 3 filled in the container 30.
1 (see FIG. 4). Fluorescent film forming solvent 31
Is a solvent type phosphor, and a mixture of three kinds of components, a solvent, a binder, and a phosphor can be used practically. As the solvent, for example, an organic solvent of nitrocellulose or ethylcellulose can be used. As the binder, for example, a powder of low melting point glass can be used. As the fluorescent material, for example, a commercially available fluorescent material in which three primary colors of red (R), green (G), and blue (B) are blended can be used. In the embodiment of the present invention, the fluorescent film forming solvent 3
In No. 1, the content of the solvent in the solution is set to, for example, about 11% by weight.

(3) Next, the second opening 22 of the glass tube 20 is connected to the suction device 35, and the suction device 35 is operated to reduce the internal pressure of the glass tube 20 to a negative pressure. As shown in (1), the fluorescent film forming solvent 31 in the container 30 is sucked and introduced from the first opening 21 of the glass tube 20, and the inside of the glass tube 20 is filled with the fluorescent film forming solvent 31. As described above, since the viscosity of the fluorescent film forming solvent 31 is set to be low, even if the inner diameter of the thin tube is 1.5 mm like the glass tube 20 according to the embodiment of the present invention, the inner diameter is further reduced to 1 mm. Even in the case of a thin tube having a diameter of 0.5 mm or less, the fluorescent film forming solvent 31 can be easily and well sucked into the glass tube 20, and the fluorescent film forming solvent 31 can be spread over the entire length of the glass tube 20 in the longitudinal direction. Can be attached evenly. The suction device 35 includes a water aspirator, a water ring pump, a steam ejector pump, an oil rotary pump,
A vacuum pumping device such as a dry rotary pump or a mechanical booster pump can be used practically.

(4) Next, the suction from the second opening 22 of the glass tube 20 is released, and the suction of the fluorescent film forming solvent 31 from the first opening 21 is stopped. Suction device 35
Is released, and the excess fluorescent film forming solvent 31 inside the glass tube 20 is discharged from the first opening 21 to the container 30 by its own weight. After the excess fluorescent film forming solvent 31 is discharged, a certain thickness of the fluorescent film forming solvent 31 adheres and remains on the inner wall of the glass tube 20.

(5) Next, as shown in FIG. 1, the glass tube 20 is mounted on the high-speed spinner 7 with the glass tube 20 held upright, and the glass tube 20 is rotated at a high speed with the tube length direction as a rotation axis. In the embodiment of the present invention, the glass tube 20 is
5000 cycles per minute or more, more preferably 10 cycles per minute
Rotate at a rotation speed of 000 cycles or more. By applying this rotation to the glass tube 20, a strong centrifugal force is applied to the fluorescent film forming solvent 31 attached to the inner wall of the glass tube 20, and the fluorescent film forming solvent 31 is strongly pressed against the inner wall of the glass tube 20, The fluorescent film forming solvent 32 strongly adhered to the inner wall of the tube 20 can be formed. In particular, the fluorescent material of the fluorescent film forming solvent 32 moves to the vicinity of the inner wall of the glass tube 20 due to centrifugal force, and the density of the fluorescent material can be increased near the inner wall of the glass tube 20. If the rotation speed of the glass tube 20 is less than 5000 cycles per minute, especially less than 3500 cycles per minute, the thickness and uniformity of the fluorescent film formed on the inner wall of the glass tube 20 cannot be sufficiently obtained. Variations in chromaticity increase over the entire length of the cold cathode fluorescent discharge tube 1. On the other hand, when the rotation speed of the glass tube 20 is set to 5,000 cycles or more per minute, the thickness and uniformity of the fluorescent film formed on the inner wall of the glass tube 20 can be sufficiently obtained, so that the cold cathode fluorescent light can be obtained. The variation in the chromaticity of the discharge tube 1 can be reduced to a level at which there is no practical problem. Further, the rotation speed of the glass tube 20 is set to 10,000
If the number of cycles is set to be equal to or more than the cycle, the thickness and uniformity of the fluorescent film formed on the inner wall of the glass tube 20 can be more sufficiently obtained. Can be eliminated.

(6) Next, as shown in FIG. 5, the second opening 22 of the glass tube 20 is connected to the drying gas generator 8. Then, by sending a drying gas from the drying gas generator 8 into the glass tube 20, the solvent contained in the fluorescent film forming solvent 32 attached to the inner wall of the glass tube 20 is volatilized. As the drying gas 80, for example, an inert gas such as dry nitrogen (N 2) gas, helium (He), or argon (Ar), or dry air can be practically used. Due to the volatilization of the solvent, a fluorescent film forming solvent 33 having a substantially uniform thickness can be formed from the fluorescent film forming solvent 32 attached to the inner wall of the glass tube 20.
Note that the solvent of the fluorescent film forming solvent 33 needs to be completely volatilized before performing the firing step described below. If the solvent remains during the firing step, voids may be generated due to the volatilization of the solvent. is there. Further, if the solvent remains during the firing step, the solvent may be oxidized and carbon may be generated in the fluorescent film, and from this point, the solvent in the fluorescent film forming solvent 31 is sufficiently removed before the firing step. It is important to keep it volatile.

(7) Next, as shown in FIG. 6, the glass tube 20 is transferred into a firing furnace (heat treatment furnace) 9, and the glass tube 20 is subjected to a heat treatment at about 700 ° C. in the firing furnace 9. By doing so, the fluorescent material can be baked on the inner wall of the glass tube 20 together with the binder of the fluorescent film forming solvent 33.
By this baking, the fluorescent film 3 can be formed on the inner wall of the glass tube 20 with a uniform film thickness, a dense film quality, and a thick film thickness. The fluorescent film 3 is preferably formed with a film thickness of, for example, about 10 μm to 20 μm.

(8) Next, a discharge electrode 4A and an electrode terminal 5A coupled thereto are disposed in one first opening 21 of the glass tube 20 in which the fluorescent film 3 is formed, as shown in FIG. Thus, one first opening 21 of the glass tube 20 is melt-bonded.

(9) Next, the inside of the glass tube 20 is evacuated from the other second opening 22 of the glass tube 20 by a vacuum exhaust device such as a turbo molecular pump, a cryopump, an oil diffusion pump, and the like. 20 is filled with the discharge gas 6 at the above pressure. Subsequently, the discharge electrode 4B and the electrode terminal 5B coupled thereto are disposed in the second opening 22 of the glass tube 20 (see FIG. 8).

(10) Then, as shown in FIG. 8, the second opening 22 of the glass tube 20 is melt-bonded, the discharge gas 6 is sealed inside the glass tube 20, and the extra glass tube 20 is removed. By cutting off, the cold cathode fluorescent discharge tube 1 shown in FIG. 2 can be completed.

In the method of manufacturing the cold cathode fluorescent discharge tube 1 described above, the fluorescent film forming solvent 31 is introduced into the glass tube 20, the glass tube 20 is rotated, and the fluorescent film forming solvent 31 is removed by centrifugal force. Press strongly against the inner wall of the pipe.
Then, the density of the fluorescent material near the inner wall of the glass tube 20 is increased. Therefore, the fluorescent film 3 having a uniform thickness, a dense film quality, and a large thickness can be easily formed on the inner wall of the glass tube 20. Therefore, when the cold-cathode fluorescent discharge tube 1 is turned on, the fluorescent film 3 having high strength against ultraviolet irradiation and sputtering can be formed, and high luminance can be stably obtained over a long period of time. As a result, a highly reliable cold cathode fluorescent discharge tube 1 can be manufactured.

Further, by lowering the viscosity of the fluorescent film forming solvent 31, the fluorescent film forming solvent 31 can be easily introduced into the glass tube 20. In particular, 1.5 mm
Also in the glass tube (glass thin tube) 20 having the following inner diameter, the fluorescent film forming solvent 31 can be easily sucked into the glass tube 20. Therefore, since the process of forming the fluorescent film 3 can be automated and the cold cathode fluorescent discharge tubes 1 can be mass-produced, the production cost and product cost of the cold cathode fluorescent discharge tubes 1 can be reduced.

Furthermore, in the method of manufacturing the cold cathode fluorescent discharge tube 1 as described above, since the high quality fluorescent film 3 can be formed on the inner wall of the glass tube 2 having an inner diameter of 1.5 mm or less, A device such as a monitor or a liquid crystal television can be reduced in size.

First Modification: In the method of manufacturing the cold cathode fluorescent discharge tube 1 according to the above-described embodiment of the present invention, the fluorescent film forming solvent 31 is sucked up while the glass tube 20 is held upright, and the glass tube is sucked up. Although the method of applying the fluorescent film forming solvent 31 to the inner wall of the glass tube 20 is adopted, the present invention arranges the glass tube 20 in a horizontal state, that is, lays the glass tube 20 in the horizontal direction, and the fluorescent film is formed inside the glass tube 20 from the horizontal direction. The forming solvent 31 may be introduced.

Second Modification: In the method of manufacturing the cold cathode fluorescent discharge tube 1 according to the embodiment of the present invention, the fluorescent film forming solvent 31 is applied to the glass tube 20 and then the glass tube 2
In the present invention, the fluorescent film forming solvent 31 is applied to the glass tube 20, and then the glass tube 20 may be rotated at a high speed while the glass tube 20 is laid down.

Third Modification: In the method of manufacturing the cold cathode fluorescent discharge tube 1 according to the above-described embodiment of the present invention, after introducing the fluorescent film forming solvent 31 into the glass tube 20, Although high speed rotation is given to the present invention,
The glass tube 20 may be rotated at a high speed at the same time as the step of introducing the fluorescent film forming solvent 31 into the glass tube 20.

Fourth Modification: In the method for manufacturing the cold cathode fluorescent discharge tube 1 according to the embodiment of the present invention, the fluorescent film forming solvent 31 is introduced into the glass tube 20 and After applying high-speed rotation, a drying gas 80 is fed into the glass tube 20 to form a fluorescent film forming solvent 33 having a uniform film thickness. A forming solvent 31 is introduced, and a drying gas 80 is fed into the glass tube 20 to form a fluorescent film forming solvent 33 having a uniform film thickness.
May be given a high-speed rotation. Alternatively, this glass tube 2
High-speed rotation may be given while the drying gas 80 is poured into the nozzles 0.

(Other Embodiments) Although the present invention has been described with the above embodiments, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples, and operation techniques will be apparent to those skilled in the art.

For example, the present invention can be applied to a double-tube discharge tube further provided with a glass tube around the cold cathode fluorescent discharge tube 1 described above.

As described above, the present invention naturally includes various embodiments and the like not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the appropriate claims.

[0041]

According to the present invention, it is possible to provide a method for manufacturing a cold cathode fluorescent lamp capable of easily forming a fluorescent film having a uniform thickness and a large thickness.

Furthermore, the present invention can provide a method of manufacturing a cold cathode fluorescent discharge tube capable of stably obtaining high luminance over a long period of time and improving reliability.

Further, the present invention can provide a method for manufacturing a cold cathode fluorescent discharge tube capable of improving productivity.

Further, the present invention can provide a method for manufacturing a cold cathode fluorescent discharge tube capable of obtaining the above-mentioned effects even with a glass tube having an inner diameter of 1.5 mm or less.

Further, the present invention can provide a method of manufacturing a cold cathode fluorescent discharge tube capable of realizing miniaturization of devices such as a liquid crystal monitor and a liquid crystal television.

[Brief description of the drawings]

FIG. 1 is a process sectional view of a cold cathode fluorescent discharge tube according to an embodiment of the present invention, which is a process sectional view following FIG. 4;

FIG. 2 is a sectional structural view of a cold cathode fluorescent discharge tube according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a cold cathode fluorescent lamp according to an embodiment of the present invention in the first step.

FIG. 4 is a process sectional view of the cold cathode fluorescent discharge tube following FIG. 3 according to the embodiment of the present invention;

FIG. 5 is a process sectional view of the cold cathode fluorescent discharge tube following FIG. 1 according to the embodiment of the present invention;

FIG. 6 is a process sectional view of the cold cathode fluorescent discharge tube following FIG. 5 according to the embodiment of the present invention;

FIG. 7 is a process sectional view of the cold cathode fluorescent discharge tube following FIG. 6 according to the embodiment of the present invention;

FIG. 8 is a process sectional view of the cold cathode fluorescent discharge tube following FIG. 7 according to the embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cold cathode fluorescent discharge tube 2, 20 Glass tube 3 Fluorescent film 4A, 4B Discharge electrode 5A, 5B Electrode terminal 6 Discharge gas 7 High-speed spinner 8 Drying gas generator 9 Firing furnace 21 First opening 22 Second Opening of 30 Container 31, 32, 33 Solvent for forming fluorescent film 35 Suction device 80 Drying gas

Continuation of the front page (72) Inventor Hisao Yoshioka 7-17-7 Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture F-term in Kowa Electric Co., Ltd. 5C028 EE02 EE17

Claims (6)

[Claims] 1. A step of introducing a fluorescent film forming solvent through at least one of the openings into a glass tube having openings at both ends, and rotating the glass tube about a tube length direction as a rotation axis. Attaching the fluorescent film-forming solvent to the inner wall of the glass tube and forming a fluorescent film from the fluorescent film-forming solvent. 2. The method according to claim 1, wherein the glass tube is rotated at a rate of 5000 cycles or more per minute, and the fluorescent film forming solvent is attached to an inner wall of the glass tube by centrifugal force.
3. The method for producing a cold cathode fluorescent discharge tube according to item 1. 3. The cold cathode fluorescent lamp according to claim 1, wherein the glass tube is rotated at 10,000 cycles or more per minute, and the fluorescent film forming solvent is attached to an inner wall of the glass tube by centrifugal force. Manufacturing method of discharge tube. 4. The cold cathode fluorescent discharge tube according to claim 2, wherein a fluorescent film is formed on an inner wall of the glass tube when the inner diameter of the glass tube is 1.5 mm or less. Method. 5. The fluorescent film forming solvent includes at least a solvent, a binder and a fluorescent material, and rotates the glass tube to attach the fluorescent material to the inner wall of the glass tube with the binder. The method according to claim 1, wherein a fluorescent film is formed on an inner wall of the glass tube by removing the solvent later. 6. The step of introducing the fluorescent film forming solvent includes: immersing one opening of the glass tube in a fluorescent film forming solvent, and sucking the fluorescent film forming solvent from the other opening of the glass tube. The method according to claim 1, wherein the method is a process.