JP2004146102A - Coating device of fluorescent liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating device of fluorescent liquid enabling the fluorescent liquid of a given thickness to be coated on an inner periphery face of a glass tube by maintaining temperature of the fluorescent liquid stored in a vessel constant and maintaining its viscosity constant. <P>SOLUTION: The coating device of the fluorescent liquid maintains viscosity constant as the vessel 7 storing the fluorescent liquid 8 in which a lower end of the glass tube 8 in a vertical posture is dipped is dipped in cooling water 17 stored in a cistern 16, and the cooling water 17 is supplied to the cistern 16 by a cooling device 18 to maintain the fluorescent liquid at a given temperature. The cooling device 18 is provided with a tank 19 storing the cooling water 17, a temperature sensor 20 detecting temperature of fluorescein liquid 6 or the cooling water 17 in the cistern 16, and a control part 21 for supplying the cooling water 17 in the tank 19 to the cistern 16 so as to keep the fluorescein liquid 6 or the cooling water 17 in the cistern 16 at the given temperature. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for applying a fluorescent liquid for manufacturing a cold cathode discharge tube used as a light source of a liquid crystal display device, and more particularly, in a manufacturing process of a cold cathode discharge tube, a fluorescent liquid having a predetermined thickness is made of glass. The present invention relates to an apparatus for applying a fluorescent liquid to be applied to an inner peripheral surface of a tube.
[0002]
[Prior art]
As a backlight of a liquid crystal display device or the like, a cold cathode discharge tube having features of high luminance, low power consumption, and low lighting start voltage is widely used. As shown in FIG. 2, the cold-cathode discharge tube is provided with bead glasses 3, 3 at both ends of a glass bulb 1 sealed with bead glasses 3, 3, and a glass bulb at the inner end of each of the introduced metal bodies 2, 2. Electrodes 4 and 4 arranged inside the end of the glass bulb 1 are attached, a fluorescent film 5 is formed on the inner peripheral surface of the glass bulb 1, and a mixed rare gas such as neon or argon and mercury are diffused and sealed in the glass bulb 1. It is the configuration that was done.
[0003]
In the initial stage of forming the fluorescent coating 5, a fluorescent liquid application device as shown in FIG. 3 is used. The apparatus for applying a fluorescent liquid includes a container 7 for storing a fluorescent liquid 6, a holder 9 for holding a glass tube 8 in a vertical position, and a suction head 10 detachably mounted on an upper end of the glass tube 8. Have been. A vacuum pump 11 for reducing the pressure inside the glass tube 8 and sucking the fluorescent liquid 6 into the glass tube 8 is connected to the suction head 10 via a pipe 12. The pipe 12 is provided with a pressure reducing valve 13 and an electromagnetic valve 14.
[0004]
Further, a liquid level detection sensor 15 for detecting that the fluorescent liquid 6 has been sucked up to a predetermined position of the glass tube 8 is provided near the glass tube 8 held by the holder 9. The liquid level detection sensor 15 is electrically connected to the electromagnetic valve 14 so that the electromagnetic valve 14 is shut off when the fluorescent liquid 6 is detected.
[0005]
In order to apply the fluorescent liquid 6 to the inner peripheral surface of the glass tube 8 by such a fluorescent liquid applying apparatus, first, the lower end of the glass tube 8 held by the holder 9 is applied to the fluorescent liquid 6 stored in the container 7. In a state of being immersed, the suction head 10 is mounted on the upper end of the glass tube 8. Then, the vacuum pump 11 is operated to reduce the pressure inside the glass tube 8. Then, the fluorescent liquid 6 stored in the container 7 is sucked into the glass tube 8 and adheres to the inner peripheral surface of the glass tube 8. When the liquid level detection sensor 15 detects the fluorescent liquid 6 sucked into the glass tube 8, the electromagnetic valve 14 operates, and the vacuum pump 11 stops sucking the fluorescent liquid 6. After that, the degree of vacuum in the glass tube 8 decreases, and the fluorescent liquid 6 naturally falls.
[0006]
The fluorescent liquid 6 attached to the inner peripheral surface of the glass tube 8 is dried and then fired at a high temperature. As a result, the fluorescent coating 5 is formed on the inner peripheral surface of the glass tube 8. However, since the fluorescent coating 5 is formed up to the end of the glass tube 8 on the side immersed in the fluorescent liquid 6, it is necessary to remove the fluorescent coating 5 in this portion in a later step. The reason why the fluorescent coating 5 is not formed on both ends of the glass tube 8 is to ensure the affinity between the glass tube 8 and the bead glasses 3.
[0007]
In addition, in order to prevent a waving phenomenon from occurring on the liquid surface of the fluorescent liquid sucked to a predetermined height, a coating apparatus for a coating liquid having a suction head provided with a suction hole of 1 to 25% of the inner diameter of the glass tube, and a device therefor. An application method is disclosed in Patent Document 1.
[0008]
[Patent Document 1]
JP-A-8-281177
[Problems to be solved by the invention]
By the way, in order for the cold cathode discharge tube to emit light in a predetermined state, the fluorescent coating 5 must be formed to a certain thickness on the inner peripheral surface of the glass tube 8. For that purpose, the viscosity of the fluorescent liquid 6 stored in the container 7 needs to be kept constant. Since the viscosity of the fluorescent liquid 6 changes depending on the temperature, it is necessary to keep the fluorescent liquid 6 at a predetermined temperature. However, since the lower ends of the glass tubes 8 are immersed in the fluorescent liquid 6 stored in the container 7 one after another, the temperature tends to rise. Therefore, during the operation of applying the fluorescent liquid 6 into the glass tube 8, the viscosity of the fluorescent liquid 6 changes, so that the fluorescent liquid 6 having a predetermined thickness is applied to many glass tubes 8. The thickness of the fluorescent film 5 formed on the inner peripheral surface of the glass bulb 1 is not constant, and the luminance of the light emitting surface differs for each cold cathode discharge tube.
[0010]
Accordingly, the present invention provides a process for manufacturing a cold-cathode discharge tube, in which the temperature of the fluorescent solution stored in the container is kept constant and the viscosity is kept constant, so that the fluorescent solution having a predetermined thickness is used for the glass tube. An object of the present invention is to provide an apparatus for applying a fluorescent liquid to be applied to an inner peripheral surface.
[0011]
[Means for Solving the Problems]
The fluorescent liquid coating apparatus of the present invention is a fluorescent liquid coating apparatus in which a lower end of a glass tube in a vertical position is immersed, and a fluorescent liquid sucked upward in the glass tube is stored in a container. Detecting the temperature of the fluorescent liquid or the cooling water in the water tank for storing the cooling water for immersing the container, and supplying the cooling water to the water tank such that the fluorescent liquid maintains a predetermined temperature. And a cooling device.
[0012]
According to the apparatus for applying the fluorescent liquid, the container storing the fluorescent liquid is immersed in the water tank storing the cooling water, and the cooling water is supplied to the water tank by the control device, so that the fluorescent liquid is heated to a predetermined temperature. The viscosity can be kept constant.
[0013]
The cooling device has a tank for storing cooling water, a temperature sensor for detecting the temperature of the fluorescent liquid or the cooling water in the water tank, and the temperature of the temperature sensor is input so that the fluorescent liquid maintains a predetermined temperature. Preferably, a control unit for supplying the cooling water in the tank into the water tank is provided.
[0014]
According to the apparatus for applying the fluorescent liquid, the temperature sensor detects the temperature of the fluorescent liquid or the cooling water in the water tank, and when the control unit determines that the temperature is higher than the predetermined temperature, the control unit Supplies the cooling water in the tank into the water tank and cools the fluorescent liquid in the container immersed in the cooling water, thereby keeping the temperature of the fluorescent liquid constant and keeping the viscosity constant.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
One embodiment of a phosphor liquid applying apparatus according to the present invention will be described with reference to FIG. The same parts as those in the related art will be described with the same reference numerals.
[0016]
In the apparatus for applying a fluorescent liquid according to one embodiment of the present invention, the container 7 storing the fluorescent liquid 6 in which the lower end of the glass tube 8 in the vertical position is immersed is the cooling water stored in the water tank 16. 17, the cooling water 17 is supplied to the water tank 16 by the cooling device 18, and the viscosity of the fluorescent liquid 6 is kept constant by keeping the fluorescent liquid 6 at a predetermined temperature. Features. The cooling device 18 includes a tank 19 for storing the cooling water 17, a temperature sensor 20 for detecting the temperature of the fluorescent liquid 6 or the cooling water 17 in the water tank 16, and the temperature of the temperature sensor 20. A control unit 21 is provided for supplying the cooling water 17 in the tank 19 to the water tank 16 so that the cooling water 17 in the water tank 16 maintains a predetermined temperature.
[0017]
The container 7 for storing the fluorescent liquid 6 is formed of a material having excellent heat conductivity so that the cooling water 17 in the water tank 16 can cool the fluorescent liquid 6 in the container 6 easily. As shown in FIG. 1, the container 7 is stably placed on the bottom of the water tank 16, and the fluorescent liquid 6 is also cooled from the bottom of the container 7 by separating the container 7 from the bottom of the water tank 16. It may be. In any case, the peripheral wall of the container 7 has such a height that the fluorescent liquid 6 and the cooling water 17 are not mixed. Stirrers 22 for stirring the fluorescent liquid 6 and the cooling water 17 are provided at the bottom of the container 7 storing the fluorescent liquid 6 and the water tank 16 storing the cooling water 17, respectively. .
[0018]
A water supply pipe 23 and a drain pipe 24 are provided between the water tank 16 and the tank 19, and a pump for supplying the cooling water 17 from the tank 19 to the water tank 16 and recovering the cooling water 17 from the water tank 16 to the tank 19. (Not shown) is provided in the tank 19. The outlet of the water supply pipe 23 in the water tank 16 is piped so as to be located near the water surface, and the water supply port of the drain pipe 24 in the water tank 16 is piped so as to be located near the water bottom. Further, the water supply pipe 23 and the drain pipe 24 are provided with valves 25 and 26 for controlling the stop and flow of the cooling water 17. The tank 19 is provided with a cooler (not shown) for maintaining the cooling water 17 at a predetermined temperature.
[0019]
The temperature sensor 20 directly measures the temperature of the fluorescent liquid 6, or measures the temperature of the cooling water 17 in the water tank 16 as shown in FIG. Then, the temperature sensor 20 and the control unit 21 are connected, the temperature of the temperature sensor 20 is input to the control unit 21, and the control unit 21 determines whether the temperature has risen above a predetermined temperature.
[0020]
When the temperature of the fluorescent liquid 6 or the cooling water 17 in the water tank 16 is higher than a predetermined temperature, the control unit 21 opens the valves 25 and 26 of the water supply pipe 23 and the drain pipe 24 and is provided in the tank 19. By operating the pump, the cooling water 17 in the tank 19 is supplied into the water tank 16, and the cooling water 17 in the water tank 16 is returned to the tank 19.
[0021]
In addition, although not shown in FIG. 1 in the present fluorescent liquid application apparatus, a holder 9 for holding a glass tube 8 in a vertical position as shown in FIG. 3 and a suction head detachably mounted on the upper end of the glass tube 8 are also provided. 10, a vacuum pump 11 connected to a suction head 10 by a pipe 12, a pressure reducing valve 13 and an electromagnetic valve 14 connected to the pipe, and a liquid level detection sensor for detecting the fluorescent liquid 6 sucked into the glass tube 8. 15 are provided.
[0022]
The present fluorescent liquid application device is configured as described above, and the operation will be described next. The temperature sensor 20 measures the temperature of the fluorescent liquid 6 or the cooling water 17 in the water tank 16, and the temperature is input to the control unit 21. The control unit 21 determines whether the temperature is a predetermined temperature, and does not operate if the temperature is the predetermined temperature.
[0023]
However, when the glass tubes 8 are successively immersed in the fluorescent liquid 6, the temperatures of the fluorescent liquid 6 and the cooling water 17 in the water tank 16 also increase. The temperature of the fluorescent liquid 6 or the cooling water 17 in the water tank 16 is detected by the temperature sensor 20 and input to the control unit 21. When the control unit 21 determines that the temperature of the fluorescent liquid 6 or the cooling water 17 has risen above a predetermined temperature, the control unit 21 opens the valves 25 and 26 of the water supply pipe 23 and the drain pipe 24 and pumps the tank 19 into the tank 19. The cooling water 17 is supplied into the water tank 16 and the cooling water 17 in the water tank 16 is returned to the tank 19 to circulate the cooling water 17. The cooling water 17 supplied into the water tank 16 is stirred in the water tank 16 by the stirrer 22, the cooling water in the water tank 16 is uniformly cooled, and the fluorescent liquid 6 in the container 7 is also stirred by the stirrer 22. And cooled evenly.
[0024]
When the cooling water 17 is supplied from the tank 19 into the water tank 16, the temperature of the cooling water 17 in the water tank 16 decreases, and the heated fluorescent liquid 6 in the container 7 is cooled to maintain a predetermined viscosity. Is done. When the controller 21 determines that the temperature of the fluorescent liquid 6 or the cooling water 17 detected by the temperature sensor 20 has reached a predetermined temperature, the valves 25 and 26 of the water supply pipe 23 and the drain pipe 24 are closed, and the pump To stop.
[0025]
If the time lag from when the cooling water 17 in the tank 19 is supplied to the water tank 16 to when the fluorescent liquid 6 in the container 7 drops to a predetermined temperature is large, the control unit 21 anticipates this time lag and takes into account the time lag. The supply of the cooling water 17 into the water tank 16 is stopped.
[0026]
As described above, by circulating the cooling water 17 between the tank 19 and the water tank 16, the predetermined temperature of the fluorescent liquid 6 is maintained, and the predetermined viscosity is maintained. Therefore, the glass tube 8 is continuously transported without interruption, and its lower end is immersed in the fluorescent liquid 6. Since the fluorescent liquid 6 maintains a predetermined viscosity, the fluorescent liquid 6 having a predetermined thickness is applied to the inside of the glass tube 8.
[0027]
Next, an embodiment will be described in which the cooling water 17 is completely replaced instead of being circulated. For example, when only one tank 19 is installed, the tank 19 is in an empty state where the cooling water 17 is not filled, and when the temperature of the fluorescent liquid 6 rises, the transfer of the glass tube 8 is performed. Is stopped, the control unit 21 opens the valve 26 of the drain pipe 24, and returns the cooling water 17 in the water tank 16 into the tank 19. Since the water supply port of the drain pipe 24 is located at the bottom of the water tank 16, most of the cooling water 17 in the water tank 16 can be returned to the tank 19.
[0028]
Then, after the cooling water 17 is cooled in the tank 19, the control unit 21 supplies the cooling water 17 in the tank 19 into the water tank 16 by opening the valve 25 of the water supply pipe 23. With the cooling water 17, the temperature of the fluorescent liquid 6 whose temperature has risen falls to a predetermined temperature, and when the viscosity reaches a predetermined viscosity, the glass tube 8 is restarted to be conveyed, and the lower end of the glass tube 8 is immersed in the fluorescent liquid 6. Then, the fluorescent liquid 6 having a predetermined thickness is applied to the inside of the glass tube 8.
[0029]
When two tanks 19 are installed, one of the tanks 19 stores the cooled cooling water 17, the other tank 19 is emptied, and the cooling water 17 in the water tank 16 is drained. The cooling water 17 in the other tank 19 is supplied into the water tank 16. When the two tanks 19 are both provided with a cooler, cooling water 17 is supplied from one of the tanks 19 into the water tank 16, and the cooling water 17 in the water tank 16 cools the fluorescent liquid 6 whose temperature has risen. During this time, the cooling water 17 supplied to the other tank 19 can be cooled, and then the cooling water 17 can be supplied from the other tank 19 into the water tank 16.
[0030]
When only one of the tanks 19 was provided with a cooler, a pipe for supplying the cooling water 17 from the other tank 19 to the one tank 19 was connected, and the cooling water 17 was supplied from the one tank 19 into the water tank 16. Thereafter, the cooling water 17 is transferred from the other tank 19 to the one tank 19 so that the cooling water 17 is cooled in the one tank 19.
[0031]
In any case, the fluorescent liquid 6 in the container 7 is immediately cooled by the cooling water 17 in the water tank 16 even if the temperature rises, and can maintain a predetermined temperature. The viscosity is maintained. Therefore, the fluorescent liquid having a predetermined thickness can always be applied to the inside of the glass tube 8.
[0032]
The present invention is not limited to the above embodiments, but can be variously modified within the scope of the technical matters described in the claims. For example, the cooling water 17 may be constantly circulated, and the controller 21 may adjust the flow rate of the cooling water 17 or the temperature of the cooling water 17 so as to keep the temperature of the fluorescent liquid 6 constant. When the cooling water 17 is completely replaced with only one tank 19, the water supply pipe 23 and the drain pipe 24 can be combined into one.
[0033]
【The invention's effect】
According to the present invention, there is provided a water tank storing cooling water for immersing a container storing the fluorescent liquid, and a cooling device for supplying cooling water to the water tank so that the fluorescent liquid maintains a predetermined temperature. As a result, the fluorescent liquid is maintained at a predetermined temperature, and a predetermined viscosity is maintained. Therefore, a predetermined thickness of the fluorescent liquid is applied in the glass tube, and a predetermined thickness of the fluorescent coating is formed. As a result, it is possible to prevent the light emitting surface luminance from being different for each cold cathode discharge tube.
[Brief description of the drawings]
FIG. 1 is a schematic view of an apparatus for applying a fluorescent liquid according to an embodiment of the present invention. FIG. 2 is a cross-sectional front view of a cold cathode discharge tube. FIG. ]
6 Fluorescent liquid 7 Container 8 Glass tube 16 Water tank 17 Cooling water 18 Cooling device 19 Tank 20 Temperature sensor 21 Control unit

Claims (2)

An apparatus for applying a fluorescent liquid such that a fluorescent liquid is applied to an inner peripheral surface of a glass tube, wherein a water tank for storing cooling water for immersing a container for storing the coating liquid, and the fluorescent liquid or the A fluorescent liquid application device, comprising: a cooling device that detects a temperature of cooling water in the water tank and supplies cooling water to the water tank so that the fluorescent liquid maintains a predetermined temperature. The cooling device has a tank for storing cooling water, a temperature sensor for detecting the temperature of the fluorescent liquid or the cooling water in the water tank, and the temperature of the temperature sensor is input, and the fluorescent liquid is maintained at a predetermined temperature. The apparatus for applying a fluorescent liquid according to claim 1, further comprising a controller configured to supply cooling water in the tank into the water tank.

Images