JPH08227658A - Surface film forming device for cathode-ray tube using electrostatic coating method and forming method thereof - Google Patents

Abstract

PURPOSE: To form the surface film of a cathode-ray tube to even thickness by keeping a face plate as a coating plane at the ground potential for applying an electrical attraction force to sprayed liquid drops. CONSTITUTION: An atomized film formation material 26 is sprayed to the face plate 4 of a cathode-ray tube 3 from an atomizer 15 laid so as to be faced thereto. The material 26 is fed from a grounded feed unit 24 to the atomizer 15 via a movable pipeline 22. Also, the atomized material 26 is electrified with an electrostatic accumulator, 16 under the application of voltage from a power supply 23. The atomizer 15, a nozzle and an electrifier 16 are suspended from a movable hanger 18 having an Y-axis rail 19 via a connector 17. In this case, the rail 19 is laid movably along an X-axis rail 20, and the atomizer 15 or the like can freely move in both X-axis and Y-axis directions. Furthermore, a travel along the X-axis and Y-axis directions can be precisely controlled with a controller 31 in terms of a speed, a travel distance or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for forming a surface coating on a face plate of a cathode ray tube used for image display such as a television and a display monitor by electrostatic coating.

[0002]

2. Description of the Related Art Generally, a cathode ray tube is operated by applying a high voltage to a phosphor screen, so that the outer surface of a face plate is charged with static electricity especially when the power is turned on and off. for that reason,
There are cases where fine dust in the air adheres to the surface of the face plate of the cathode ray tube to contaminate it, or when the user touches the display surface, it discharges and gives an electric shock. Further, since the face plate of the cathode ray tube has a smooth surface having a curved surface that is convex outward, the display image becomes difficult to see when external light is reflected. In particular, when a bright background image such as an illumination lamp or a window is reflected, the image displayed in the reflected portion becomes almost invisible.

In order to eliminate such a charging phenomenon and reflection of external light on the outer surface of the face plate of the cathode ray tube, a cathode ray tube having a film having an antistatic and antireflection function on the outer surface of the face plate has come to be used. It was For example, Japanese Patent Publication No. 54-2820 discloses an antistatic and antireflection film in which a conductive indium oxide film and a low refractive index transparent film are laminated on the outer surface of a face plate. Further, in JP-A-1-154444, an antistatic and antireflection effect is obtained by coating and fixing a mixture of SiO2 fine particles and additives such as hygroscopic metal salt particles and conductive metal oxide particles with a SiO2 thin film. Certain coatings are disclosed. As a method for forming these coatings, a vacuum deposition method is used for the former and a spin coating method is used for the latter. Further, it is disclosed that these coatings can be formed by a sputtering method, a gas phase reaction method, a dipping method, a spray method or the like.

However, the coating film forming method as described above has advantages and disadvantages. For example, a physical film forming method such as a vacuum vapor deposition method or a sputtering method can obtain a film which is smooth and has a high packing density suitable for an optical film. It is extremely difficult to form a film, and the curved surface makes the difficulty even higher. In addition, a high vacuum is required to form the film, and at least the outer surface of the face plate and, in some cases, the entire cathode ray tube must be held in a vacuum device. Inferior to the law.

Among the chemical film forming methods such as the gas phase reaction method, the spin coating method, the dipping method, and the spraying method, the spin coating method and the dipping method are used to form a uniform film. , Precise control of humidity, face plate temperature, air flow, etc. is required. If these conditions are not optimal, the film thickness and packing density will be uneven,
The surface may be uneven. For example, in the spin coating method, radial unevenness may occur due to rotation, or the film thickness may differ between the central portion and the peripheral portion. Furthermore, although it is relatively easy to obtain a smooth film by the dipping method, film thickness distribution occurs along the pulling direction, and the viscosity and surface tension of the liquid in the dipping tank change with time, resulting in film characteristics. Change and cause variations among products. In particular, these problems become more remarkable as the area for forming the coating film increases. Further, the gas phase reaction method generally requires expensive organic metal raw materials, and thus the cost is high.

On the other hand, the spray method does not affect the film forming property even if the area where the film is formed is large, and it is possible to form a film on a curved surface, and the mass productivity is high. Further, since the coating liquid is stored in a closed container, it is easy to control the liquid temperature and the viscosity, and the variation among products, which is a problem in the dipping method, is small. However, it is difficult to form a film having a smooth surface by the spray method, and a film is often formed in an island shape, which may not satisfy the characteristics as an optical film. Further, since the ratio of the droplets used for film formation is low among the sprayed droplets, most of them are unnecessary droplets. This is called overspray, and unnecessary droplets are either collected or dried to become dust floating in the air. In this way, the dust generated by overspray is trapped in the coating film by the subsequent spraying and becomes spot-like unevenness.

By the way, one of the spray-type coating film forming methods is an electrostatic coating method. In this method, droplets atomized by a rotary atomizer or a spray gun are electrostatically charged and applied to an object to be coated. In this case, the object to be coated is electrically set to the ground potential. Since the atomized and charged droplets are attracted to the object to be coated by an electric attractive force, it is possible to obtain a dense and smooth film as compared with a usual spray method. Also, the amount of overspray is reduced, and ideally 90% or more of the sprayed droplets are used for film formation, and the occurrence of spot-like unevenness due to dust caused by overspray can be suppressed to a low level. If this electrostatic coating method can be applied to the formation of the surface coating of the cathode ray tube, it can be expected to be extremely effective in terms of mass productivity and cost.

[0008]

However, the face plate of the cathode ray tube is made of glass and has a very high surface resistance and no electrical conductivity. If it is a thin flat glass with a thickness of up to about 2 mm, it can be electrostatically applied by placing it on an electrically conductive metal plate or the like and setting the metal plate to the ground potential, but the face plate has a glass thickness. Since it is 10 mm or more and the shape is composed of a cubic curved surface, it cannot be adhered to the metal plate, and such a method cannot be adopted. Japanese Patent Application Laid-Open No. 5-49975 discloses a method of electrostatically applying a hollow object to a gas or vapor in the space on the back side of the object to be applied by applying an electric charge opposite to that of the sprayed droplets. . However, since the cathode ray tube is evacuated, it is impossible to supply gas or the like to the inside.

The present invention has been made in order to solve the above problems, and the surface of a cathode ray tube is set by setting the face plate, which is the surface to be coated, to the ground potential to exert an electric attraction force on the sprayed droplets. An object of the present invention is to provide a method and an apparatus for forming a coating film by an electrostatic coating method.

[0010]

A surface coating forming apparatus for a cathode ray tube by an electrostatic coating method according to a first invention is an apparatus for forming a surface coating on a face plate of a cathode ray tube and is provided on an inner surface of the face plate. Predetermined conductive film
The first potential setting means for setting the potential of the second potential setting means, the second potential setting means for setting the film forming material sprayed on the outer surface of the face plate to the predetermined second potential, and the second potential setting means. It is provided with a spraying means for spraying the above-mentioned film forming material set to a predetermined second potential onto the face plate to form a surface film having a uniform film thickness.

In the apparatus for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the second invention, the first potential setting means sets the face plate to a predetermined first potential via the anode button of the cathode ray tube. To do. In the apparatus for forming a surface coating film of a cathode ray tube by the electrostatic coating method according to the third invention, the first potential setting means sets the conductive film provided on the inner surface of the face plate alone to a predetermined first potential. It is a thing.

According to a fourth aspect of the present invention, there is provided a surface coating forming apparatus for a cathode ray tube by the electrostatic coating method, which holds a face plate of the cathode ray tube so as to face the spraying means, and a rotating means for rotating the held cathode ray tube. The rotating means rotates the cathode ray tube at a predetermined speed, and the spraying means moves at a predetermined direction and speed. In the apparatus for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the fifth aspect of the invention, the spraying means moves on the outer surface of the face plate to spray the coating forming material. A surface coating forming apparatus for a cathode ray tube by an electrostatic coating method according to a sixth aspect of the present invention comprises an explosion-proof band attached to the cathode ray tube as a second layer.
A predetermined third value that is greater than the first potential and less than the first potential.
It is provided with a means for setting the electric potential.

According to a seventh aspect of the present invention, there is provided a method for forming a surface coating on a cathode ray tube by means of electrostatic coating, wherein the surface coating is formed on the face plate of the cathode ray tube by electrostatic coating. Membrane given first
And the film-forming material sprayed on the outer surface of the face plate is set to a predetermined second potential,
It is sprayed on a face plate to form a surface coating having a uniform film thickness.

In the method for forming a surface coating on a cathode ray tube by the electrostatic coating method according to the eighth aspect of the present invention, the face plate is rotated at a predetermined speed and moved from the center to the end of the outer surface of the face plate to form the coating. The material is sprayed. A method of forming a surface coating film on a cathode ray tube by an electrostatic coating method according to a ninth aspect of the present invention sprays a coating film forming material on the outer surface of the face plate while reducing the moving speed from the central portion to the end portion. .

A method of forming a surface coating on a cathode ray tube by an electrostatic coating method according to the tenth aspect of the invention is a method of forming a surface coating on a face plate of a cathode ray tube by electrostatic coating.
The conductive film provided on the inner surface of the face plate is set to a predetermined first electric potential, and the first film forming material sprayed on the outer surface of the face plate is set to a predetermined second electric potential. Sprayed and conductive 1
A second coat is formed by forming a second coat and further spraying a second coat forming material on the first coat.

In the method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the eleventh invention, the first coating forming material is fine particles containing at least one of tin oxide, indium oxide and zinc oxide as a component. Is included. In the method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the twelfth aspect of the invention, the first coating forming material is a fine particle containing at least one of tin oxide, indium oxide and zinc oxide as an organic solvent. It is dispersed in. In the method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the thirteenth invention, the average particle diameter of the fine particles in the coating forming material is 200 Å (angstrom) or less.

In the method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the fourteenth invention, the first coating forming material forming the first layer of the coating on the outer surface of the face plate is 1
The composition is changed to a composition containing at least one of tin oxide, indium oxide, and zinc oxide by heat treatment after the electrostatic coating of the layer. In the method for forming a surface coating film of a cathode ray tube by the electrostatic coating method according to the fifteenth invention, the coating material has a boiling point of 100 ° C. or higher and 160 ° C. or lower,
The surface tension is 25 dyne / cm or less and the viscosity is 2 cps or less.

A method of forming a surface coating on a cathode ray tube by an electrostatic coating method according to the sixteenth invention is a method of forming a surface coating on a face plate of a cathode ray tube by electrostatic coating.
An electrode is provided in advance on a portion other than the image display surface of the face plate, a first surface coating film is formed by a first film forming material, and the electrode is set to a predetermined first potential,
Further, the second film forming material is used to form a second surface film. In the method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the seventeenth invention, the electrode forms a first surface coating on the surface of the face plate and then forms a portion other than the image display surface of the face plate. To form.

A method of forming a surface coating of a cathode ray tube by an electrostatic coating method according to the eighteenth invention is one in which a coating forming material other than a surface coating formed on the surface of the face plate is prevented from adhering to the surface of the face plate. Is. First
According to a ninth aspect of the present invention, there is provided a method of forming a surface coating film on a cathode ray tube by an electrostatic coating method, wherein a second explosion-proof band attached to the cathode ray tube
A predetermined third value that is greater than the first potential and less than the first potential.
It is set to the electric potential of.

[0020]

In the surface coat forming apparatus for a cathode ray tube by the electrostatic coating method according to the first aspect of the invention, the conductive metal film provided on the inner surface of the face plate of the cathode ray tube is set to a predetermined first potential, The film forming material sprayed on the face plate is set to a predetermined second potential, and an electric attractive force is generated between the face plate and the film forming material. In the apparatus for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the second aspect of the invention, the first potential setting means comes into contact with the anode button of the cathode ray tube, so that the conductive film formed on the inner surface of the face plate is predetermined. Can be set to the first electric potential.

In the apparatus for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the third aspect of the invention, since the first potential setting means contacts the conductive film provided on the inner surface of the face plate alone, The constituent face plate itself can be set to a predetermined first potential. A surface coating forming apparatus for a cathode ray tube by an electrostatic coating method according to a fourth aspect of the present invention holds a face plate of the cathode ray tube facing a spraying means and holds the held cathode ray tube while rotating the cathode ray tube at a predetermined speed. Apply the forming material.

In the surface coating forming apparatus for a cathode ray tube by the electrostatic coating method according to the fifth aspect of the invention, the spraying means is moved on the outer surface of the face plate to spray the coating forming material.
The film forming material is uniformly applied to the outer surface of the face plate. In the surface coating forming apparatus for a cathode ray tube by the electrostatic coating method according to the sixth aspect of the present invention, the explosion-proof band attached to the cathode-ray tube is set to the predetermined third potential, so that the sprayed film-forming material becomes the explosion-proof band. It does not adhere and the film-forming material does not scatter on parts other than the face plate.

In the method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the seventh aspect of the invention, a conductive film provided on the inner surface of the face plate of the cathode ray tube facing the face plate has a predetermined first potential. And a coating film forming material that forms a coating film on the outer surface of the face plate is set to a predetermined second potential, and is sprayed on the face plate to correspond to a conductive film provided on the inner surface of the face plate. An electric attractive force acts between the metal back and the black matrix and the charged film forming material. A method of forming a surface coating film on a cathode ray tube by an electrostatic coating method according to an eighth aspect of the present invention rotates a face plate at a predetermined speed and moves the face plate outer surface from a central portion to an end portion thereof to form a coating material. To spray.

In the method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the ninth aspect of the invention, the face plate is rotated at a predetermined speed, and the face plate is moved from the central portion to the end portion of the outer surface thereof. The film-forming material is sprayed while slowing down the speed to evenly apply the film-forming material to the face plate surface. In the method of forming a surface coating of a cathode ray tube by the electrostatic coating method according to the tenth aspect of the invention, since the electrically conductive surface coating is formed as the coating of the first layer, the surface coating of the first layer has a predetermined thickness. The first potential can be set, and the second-layer coating can be formed on the first-layer coating by an electrostatic coating method.

A method for forming a surface coating on a cathode ray tube by the electrostatic coating method according to the eleventh invention is tin oxide, indium oxide,
Alternatively, since a conductive coating can be formed by electrostatically applying the first coating forming material containing fine particles containing at least one kind of zinc oxide as a component, the face plate can be formed into a predetermined first layer. If the potential is set, the first-layer coating can be set to the first potential. A method of forming a surface coating of a cathode ray tube by an electrostatic coating method according to a twelfth aspect of the invention is a coating forming material in which fine particles containing at least one of tin oxide, indium oxide and zinc oxide are dispersed in an organic solvent. Since the conductive coating is formed as the first layer by using this, the surface coating of the first layer can be set to the first potential by setting the face plate to a predetermined first potential.

In the method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the thirteenth invention, a coating forming material composed of fine particles having an average particle size of 200Å (angstrom) is used.
By forming the surface coating, haze (cloudiness value) is 1%
The following films can be obtained. A method of forming a surface coating of a cathode ray tube by an electrostatic coating method according to a fourteenth invention, wherein at least one of tin oxide, indium oxide, or zinc oxide is heat-treated after electrostatically coating the first layer coating. Since the first film forming material that changes to the composition of the component is used,
It is possible to form a coating that is electrically conductive and that maintains transparency as a display screen.

In the method for forming a surface coating film on a cathode ray tube by the electrostatic coating method according to the fifteenth invention, the boiling point is 100 ° C. or higher.
0 ° C or less, surface tension 25dyne / cm or less, viscosity 2cp
Since the film forming material having a thickness of s or less is used, a surface film having a uniform film thickness can be formed. According to a method of forming a surface coating of a cathode ray tube by an electrostatic coating method according to a sixteenth invention, an electrode is provided in advance on a portion other than an image display surface of a face plate to form a non-conductive coating on the first layer. However, since the electrode provided in advance is in contact with the first-layer coating, the electrode can be set to a predetermined first potential, and the second-layer coating can be formed by electrostatic coating. .

According to a seventeenth aspect of the present invention, there is provided a method for forming a surface coating film on a cathode ray tube by the electrostatic coating method, which comprises:
By providing an electrode on a portion other than the image display surface of the face plate, the first-layer coating can be set to a predetermined first potential, and the second-layer coating can be formed by electrostatic coating. You can In the method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the eighteenth invention, a waste coating forming material other than a surface coating formed on the surface of the face plate does not adhere to the face plate. First
In the surface coating forming method for a cathode ray tube by the electrostatic coating method according to the ninth aspect of the invention, since the explosion-proof band attached to the cathode-ray tube is set to the predetermined third potential, the sprayed film forming material is attached to the explosion-proof band. The film-forming material does not scatter on parts other than the face plate.

[0029]

【Example】

Example 1. An embodiment of the present invention will be described below. FIG. 1 shows an apparatus for manufacturing a surface coating type cathode ray tube. In the figure, 1 is a grounding electrode, 2 is a support for supporting a cathode ray tube, 3 is a cathode ray tube, and 4 is a face plate which is a front portion of the cathode ray tube. Reference numeral 5 is an anode button, 6 is an explosion-proof band, 7 is a metal fitting attached to the explosion-proof band, and 8 is a column for supporting the cathode ray tube. Reference numeral 9 is a ring-shaped terminal provided around the sliding electrode, 10 is a sliding electrode provided on the rotary shaft of the rotating device, 11 is a cathode ray tube holding portion provided around the cathode ray tube, and 12 is a cathode ray tube. Rotating device for rotating, 13 is ground cable, 14, 25,
34 is a ground plane.

Further, 15 is an atomizer for atomizing and spraying the film material, 15a is a nozzle of the atomizer, 16 is an electrostatic charger for charging the film material, 17 is a connector, and 18 is a movable suspension. Metal fittings, 19 is a Y-axis rail, 20 is an X-axis rail, 21 is a cable for power supply, 22 is a movable pipe for sending the membrane material to the atomizer, 23 is a power source, and 24 is a feeder for supplying the membrane material. , 26 are film forming materials. Reference numeral 31 is a controller that controls the movement of the atomizer 15, and 32 is a conductive brush that is provided on the inner wall of the cathode ray tube holding portion 11 and is in contact with the metal fitting 7.

An apparatus for forming a surface coating film on a cathode ray tube by the electrostatic coating method will be described below. The cathode ray tube 3 is supported by the support base 2 installed on the rotating device 12 of the cathode ray tube holding portion 11, and is further fixed to the column 8 by the metal fitting 7 attached to the explosion-proof band 6. Further, the anode button 5 of the cathode ray tube 3 is connected to the grounding electrode 1 erected on the rotating device 12. The grounding electrode 1 has elasticity, and when the cathode ray tube is inserted into the support base 2, the grounding electrode 1 moves as shown by an arrow as shown in FIG. 2 and is pressed to the anode button by spring pressure. (The dotted line is the position of the ground electrode before the cathode ray tube is inserted). The grounding electrode 1 is connected to a ring-shaped terminal 10 provided on the rotating shaft of the rotating device 12, and is grounded to the grounding surface 14 via the sliding electrode 9 and the grounding cable 13.

Then, the atomized film forming material 2 from the atomizer 15 arranged so as to face the face plate 4 of the cathode ray tube 3 is formed.
6 is sprayed on the face plate 4. The film forming material passes from the grounded feeder 24 through the movable pipe 22 to the atomizer 1.
5 is supplied. The film forming material 26 which is atomized by the atomizer 15 is charged by the electrostatic charger 16 to which a voltage is supplied from the power source 23 by the cable 21. These atomizer 15, nozzle 15a of atomizer 15, charger 16
Is suspended by a movable suspending member 18 movably attached to a Y-axis rail 19 via a connector 17. Further, the Y-axis rail is installed on the X-axis rail so as to move along the X-axis rail 20, and the atomizer 15 and the like move to the X-axis rail.
It can move freely in the axial and Y-axis directions. With respect to the movement on the X-axis and the Y-axis, the speed and the moving distance are precisely controlled by the controller 31.

The surface coating forming method will be described in more detail below. In the apparatus shown in FIG. 1, the completed cathode ray tube sphere is attached to the support base of the cathode ray tube holding portion so that the face plate surface faces upward, the metal fitting 7 is fixed by the column 8, and the cathode ray tube is supported from the side. Further, the anode button 5 and the ground electrode 1 are connected to ground the cathode ray tube 3. The ground electrode 1 is a spring type electrode, and the ground electrode 1 is pressure-bonded to the anode button 5 of the cathode ray tube 1 attached to the support. Although a spring-type ground electrode having elasticity is used here, its shape is not particularly limited as long as it can contact the anode button and conduct electricity to the ground surface. For example, by using something like a socket, the anode button 5
You can connect to. The cathode ray tube 3 is electrically connected to a sliding electrode from a ground electrode 1 (spring type ground electrode) connected to an anode button 5 through a ring-shaped terminal, and then connected to a ground potential by a ground cable 13.

The film forming material 26 is prepared, for example, by a solution in which 100 g of an alkyl silicate is mixed with 40 cc of ethyl alcohol and 60 g of methyl ethyl ketone (MEK). This solution is supplied from the feeder 24 (pump) at a rate of 500-min.
It is sent to the atomizer 15 at a liquid feed rate of 1500 cc, preferably 1000 cc per minute, and is made into a mist. further,
A voltage is applied to the spray nozzle 15a of the atomizer 15 by the electrostatic charger 16, and the potential of the film forming material 26 that has become mist (fog) by the atomizer 15 is -10 kv with respect to the ground potential.
Electrostatic coating is performed at a pressure of -20 kv, preferably -15 kv. The reason why the potential of the film forming material is set to the above value is that the electrostatic attraction effect is low and the liquid utilization efficiency becomes 80% or less at −10 kv or more. Also, at −20 kv or less, the electrostatic attraction effect is high and it becomes difficult to control the film thickness.

By the way, the atomizer 15 has a hanging metal fitting 18
It is suspended by the Y-axis rail so that it can move freely on the Y-axis rail. Further, the Y-axis rail is attached to the X-axis rail so that it can freely move on the X-axis rail. In this way, the atomizer 15
Can freely move in the X and Y axis directions with respect to the surface of the cathode ray tube. The electrostatic coating on the surface (face plate 4) of the cathode ray tube 3 is performed by the hanging metal fitting 18 as described above.
The atomizer 15 suspended on the shaft rail is moved by moving on the X-axis rail 20 and the Y-axis rail 19. This makes it possible to manufacture a cathode ray tube having a dense and smooth silicate monolayer film and having a surface coating with increased film strength formed.

When electrostatic coating is performed using the same coating film forming material 26, the cathode ray tube 3 fixed to the support base 2 is rotated by the rotating device 12 to a preset rotation speed, for example, 200 rpm. When reaching, the uniformity of the surface coating is further improved by gradually moving the spray nozzle 15a from the center of the face plate 4 toward the end portion (peripheral portion) while performing electrostatic coating. The nozzle moving speed at this time varies depending on the liquid properties such as the viscosity of the coating solution, but it is moved at a moving speed of about 5 cm per second at the initial speed, and the speed is gradually reduced as it approaches the end of the face plate 4. Is desirable. The film thickness is 1
5 nozzles for 100Å (angstrom)
It is moved at cm / s. Further, since the coating surface is rotating, the moving speed of the coating surface corresponding to the position of the nozzle 15a increases as the nozzle 15a moves from the center to the end of the face plate 4, so that the moving speed of the nozzle 15a. Is slowed down so that the film thickness of the surface coating becomes constant.

As a result, a cathode ray tube having an extremely dense and smooth silicate monolayer film can be obtained as compared with the conventional spin coating method. Specifically, compared to the conventional spin coating method, the surface roughness is 1/2. The film strength is pencil hardness 9H or more (the conventional value is 7H to 9H). The uniformity of the film is improved (the unevenness of the film in the central portion). Has been solved). Further, in the method of forming the surface coating of the cathode ray tube configured as described above, by setting the anode button to the ground potential, the metal back on the inner surface of the face plate and the electrical discharge between the black matrix and the charged spray droplets are achieved. Such an attractive force acts to form a flat and dense film on the face plate surface.

Example 2. Another embodiment of the present invention will be described below. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 3 shows an apparatus for manufacturing a surface coat forming type cathode ray tube for forming a coat on the surface of the face plate 4 alone. In the figure, 27 is a black matrix formed on the inner surface of the face plate 4, 28 is a phosphor formed on the back side of the black matrix 27, and 29 is a metal back made of an aluminum film, which is formed on the back side of the phosphor 28. Has been done. Reference numerals 30 and 31 denote an internal fixing jig and an external fixing jig for fixing the face plate 4 on the rotating device base.

The apparatus for manufacturing the surface coating type cathode ray tube according to the second embodiment will be described below. The face plate 4 of the cathode ray tube 3 is fixed on the rotating device 12 by an external fixing jig 31 and an internal fixing jig 30. The black matrix 27 and the phosphor 2 are provided on the inner surface of the face plate 4.
8 and a metal back 29 are provided, and the internal fixing jig 30 also serves as an electrode for connecting the metal back 29 or the black matrix 27 on the inner surface of the face plate to the ground potential. Further, the internal fixing jig 30 is connected to the ring-shaped terminal 10 and grounded to the ground plane 14 via the sliding electrode 9 and the ground cable 13.

The surface coating of the cathode ray tube is formed as follows. First, the feeder 2 in which the film forming material 26 is grounded
4 to the atomizer 15 through the movable pipe 22.
The electrostatic charger 16 is supplied with a voltage from the power supply 23 by the cable 21, and applies a voltage to the spray nozzle 15 a of the atomizer 15. The film forming material 26 atomized by the atomizer 15 is charged by the spray nozzle 15 a to which a voltage is applied by the electrostatic charger 16, and is atomized toward the face plate 4 of the cathode ray tube 3. 26 is sprayed.
The atomizer 15, the spray nozzle 15a, and the charger 16 are movable hanging fittings 1 along the Y-axis rail 19 via a connector 17.
Suspended at 8. Further, the Y-axis rail is installed so as to move along the X-axis rail 20, and the movement on the X-axis and the Y-axis is installed so that the speed and the moving distance are precisely controlled by the controller. The atomizer 15 thus moves over the face plate 4 of the cathode ray tube 3.

The operation of the apparatus for forming a surface coating of a cathode ray tube by the electrostatic coating method and the method therefor will be described below.
FIG. 4 is a view showing the face plate 4 alone. In the figure, 35 is a plate-shaped copper tape attached to the skirt portion on the inner surface of the face plate 4. The black matrix 27 and the phosphor 28 are applied to the inner surface of the face plate 4 alone of the cathode ray tube 3 by an ordinary slurry method,
After performing filming with the emulsion, a copper tape is attached to a part of the skirt portion on the inner surface of the face plate 4. After that, a heat treatment process for aluminum vapor deposition and filming decomposition was performed to form an aluminum vapor deposition film (metal back 29) on the attached copper tape 35.

Next, in the apparatus shown in FIG. 3, the face plate 4 alone, which has been subjected to the above-mentioned treatment, is attached to the rotating device 12 made of a metal frame having a rotating mechanism with the surface thereof facing upward, and the internal fixing jig 30 and the outside are fixed. It is sandwiched and fixed by the fixing jig 31. The face plate 4 is electrically connected from the portion of the copper tape 35 that is in contact with the internal fixing jig 30, and is grounded to the ground potential 14 via the ring-shaped terminal 10, the sliding electrode 9 and the ground cable 13. The aluminum vapor deposition film formed on the black matrix 27 and the copper tape 35 is set to the ground potential through the metal frame.

Then, as in the case of the first embodiment, the film forming material 26 is sprayed onto the face plate 4 by the atomizer 15 to perform electrostatic coating. Also by this method, a dense, uniform and high-strength surface coating can be obtained as compared with the conventional spin coating method. In the method for forming the surface coating of the cathode ray tube configured as described above, the metal back on the inner surface of the face plate and the black matrix are grounded, so that an electric attractive force can be exerted between the metal spray and the charged spray droplets. A flat and dense film can be formed on the face plate surface.

Example 3. Another embodiment of the present invention will be described below. In this embodiment, a surface coating consisting of two layers is formed on the surface of the cathode ray tube. FIG. 6 is a detailed view of the supply portion of the film forming material in the case of forming a two-layer surface film. In FIG. 6, the atomizer 15 and the feeder 24 of FIG. 1 are modified so that two types of film forming materials can be fed. In the figure, 37 is a feeder for the film forming material for the first layer, 38 is a feeder for the film forming material for the second layer, 4
Reference numeral 1 is an atomizer provided with spray nozzles 41a and 41b for spraying a film forming material for the first and second layers. In the apparatus shown in FIG. 1, the completed cathode ray tube sphere is attached to the support base 2 so that the face plate 4 surface faces upward, and further, from the anode button 5 of the cathode ray tube 3 to the spring-type grounding electrode 1, the ring-shaped terminal 10, Conduction was established through the sliding electrode 9 and it was connected to the ground potential. In the case of forming a surface coating consisting of two layers, the feeder is replaced with the one shown in FIG.

Next, as a solution forming the first layer of the conductive coating formed on the face plate 4 of the cathode ray tube, a fine powder of antimony-doped tin oxide having an average particle size of 20 nm or less.2.
1000 cc of an aqueous dispersion obtained by dispersing 5 g in distilled water was used as an ethyl cellosolve 8 solvent for adjusting the surface tension and the boiling point.
Dilute with 00cc, diacetone alcohol 150cc, ethyl alcohol 400cc, surface tension 15dyne / cm,
Prepare so that the boiling point is 150 ° C and the viscosity is 1 cps. When the mixing ratio of the solution is set to the above value, the characteristics suitable for the film forming material can be obtained. This has a surface tension of 25 dyne / cm
In the above case, when the solution is applied, it does not become a film but becomes island-shaped. Further, if the boiling point is 100 ° C. or lower, the sprayed droplets will be dried before reaching the printed material (panel). further,
When the boiling point is 160 ° C. or higher, the film strength becomes 7H or lower. Also, if the viscosity is 2 cps or more, the liquid cannot be sprayed. For these reasons, each characteristic of the solution is set to the above value.

While this solution is being stirred, it is sent to the atomizer 41 at a liquid sending rate of 500 to 1500 cc / min, preferably 1000 cc / min by the feeder 37 (quantitative pump). And
By the electrostatic charger 16 supplied with the voltage from the external power source 23, the film forming material (droplets) for forming the first layer misted by the atomizer 41 is -10 kV with respect to the ground potential.
A voltage is applied to the spray nozzle 41a of the atomizer 41 so that the film forming material is charged so that the voltage becomes about -20 kV, preferably -15 kV. When the charged voltage is −10 kV or more, the electrostatic attraction effect is low, the solution utilization efficiency is 80% or less, and when the charged voltage is −20 kV or less, the electrostatic attraction effect is high and it is difficult to control the film thickness. I have chosen.

Next, the cathode ray tube 3 fixed to the support base 2
And rotate it at a preset rotation speed, for example 20
When reaching 0 rpm, the spray nozzle 41a is gradually moved from the center to the end of the face plate 4 while performing electrostatic coating using the film forming material charged as described above. The nozzle moving speed at this time varies depending on the liquid physical properties such as the viscosity of the coating solution, but it is desirable to move the nozzle in one direction at a moving speed of about 5 cm per second and gradually decrease the speed as it approaches the end. The rotation speed of the cathode ray tube fixed to the support is 140 to 160.
The rpm is desirable, and the film thickness in the central portion becomes thicker at 140 rpm or less, and becomes thinner at 200 rpm or more.

The nozzle movement for forming the surface coating can be repeated, and reciprocating movement may be performed several times on the face plate in order to increase the film thickness.
Then, when the desired film thickness is reached, electrostatic coating is stopped, and the rotation is maintained for 1 minute to dry the solvent and then stop. Further, in order to control the drying rate of the solvent, the surface of the face plate 4 may be preheated with an infrared heater or the like. The charged film forming material (droplets) is attracted to the ground potential and the face plate 4
Electrostatically coated on top, but a few kV for explosion-proof band of cathode ray tube
If the negative potential of is applied, the liquid droplets will not be scattered to the portion other than the face plate, and the (liquid) utilization efficiency of the film forming material is further improved.

Further, as shown in FIG. 1, the conductive brush 32 in contact with the explosion-proof band of the cathode ray tube fixed to the support base.
Applies a negative potential. That is, the ground potential 34
A negative potential of several kV is applied to the explosion-proof band 6 of the cathode ray tube 3 through the power source 33 and the conductive brush 32 which are grounded to the. The conductive brush 32 is provided on the inner wall of the cathode ray tube holding portion surrounding the rotating device 12. As described above, by charging the explosion-proof band provided around the face plate to the same electric potential as the sprayed droplets, the droplets will not adhere to the explosion-proof band, thus reducing wasted droplets. It is possible to suppress overspray, which is a source of dust. Further, since it is possible to reduce the generation of dust, it is possible to prevent dust from being taken into the spray droplets and causing the surface coating film to have a non-uniform thickness.

Next, the application of the second layer will be described. First, in order to bring the first layer obtained by the above method to the ground potential, after forming the first layer, as shown in FIG. 5, an electrode made of a copper tape 36 in the form of a plate of copper was used to display an image on the surface of the cathode ray tube. Paste from the part other than between the anode button. And
Conduction is established from this electrode portion, the first-layer coating is set to ground potential, and the second-layer coating is formed by electrostatic coating. FIG. 6 shows a detailed view of the coating film forming material supplying portion. The supply device is provided with first and second layer supply devices 37 and 38, and the film forming material is applied from the respective supply devices through the first and second nozzles 41a and 42a.

The solution applied to the second layer is, for example, 2000 cc of alkyl silicate (ethyl silicate 40) and a suitable solvent such as 1500 cc of isopropyl alcohol are added to have an azeotropic point of 130 ° C., a surface tension of 20 dyne / cm and a viscosity of 2
Dilute to cps and rotate the cathode ray tube 3 in the same manner as when forming the first layer to perform electrostatic coating. When the desired film thickness is reached, stop electrostatic coating and leave the cathode ray tube for 1 minute. Rotate 3 and then stop.

The electrostatic coating film of the cathode ray tube 3 obtained by such a method is a dense and smooth two-layer film and is useful as a low reflection / antistatic film on the surface of the cathode ray tube. FIG. 7 is an enlarged cross-sectional view of the surface portion of the face plate, and the surface coating consisting of two layers is formed as shown. By forming the surface coating by the electrostatic coating method, a two-layer film having extremely excellent film thickness control, film quality and smoothness as compared with the conventional manufacturing method was obtained. Further, the utilization efficiency of the film forming material used in electrostatic coating was 95% for both the first layer and the second layer.

FIG. 8 is a characteristic diagram comparing the reflectance of the surface of the cathode ray tube according to the present invention with that of the conventional one. In the figure, A is the reflectance of the surface of the cathode ray tube by the conventional manufacturing method, and B is the reflectance of the surface of the cathode ray tube by the manufacturing method according to Example 3 of the present invention. A is a spin-coating method in which the first layer is a conductive coating made of an antimony-doped tin oxide solution having an average particle size of 20 nm, and the second layer is a mixed solution of ethyl silicate and ethyl alcohol on the face plate of the completed cathode ray tube. It is a two-layer film having low reflection and antistatic effect. A and B are reflection spectra of the conventional example and the example, respectively. Compared to the surface coating by the conventional spin coating method, the surface coating formed by the electrostatic coating method according to the present invention is the first layer of antimony. Since the packing density of the fine particles of doped tin oxide and the uniformity of the film thickness are high, the minimum reflectance is low and a good low reflection film can be obtained. Specifically, the minimum reflectance was improved from 1.2% (conventional) to 0.8%,
It is possible to suppress reflection of external light and the like reflected on the screen, and it is possible to provide a screen in which the image is easy to see.

In this embodiment, the copper tape 36 is provided between the anode button 5 and a portion other than the image display portion on the surface of the face plate after forming the first layer coating film. The electrode may be provided before the coating of (1) is formed. In this case, since the electrode provided in advance contacts the first layer coating, the first layer coating can be set to the ground potential by setting the anode button 5 to the ground potential.

Embodiment 4 FIG. Another embodiment according to the present invention will be described below. In the present embodiment, the surface is previously N
ESA film [tin oxide (SnO2) vapor phase chemical vapor deposition method (CVD method)
The film formed in [1] is used to form a second-layer film on the face plate. FIG. 9 is a diagram in which a face plate with a NESA film is set in the apparatus. In the figure, 4a is a face plate with a NESA film having a film formed by the NESA film 40 on its surface, and 30a and 31a are an internal fixing jig and an external fixing jig for fixing the face plate 4a. Further, the external fixing jig 31a is the ring-shaped terminal 1.
It connects to the ground plane 14 through the ground cable 13 from the sliding electrode 9 provided around the ring-shaped terminal 10. 39 is the face plate 4
It is a copper tape that is attached and fixed to a portion other than the screen display on the NESA film 40 formed in a by a conductive adhesive.

Next, the formation of the surface coating will be described. The face plate 4a is fixed to the apparatus by an internal fixing jig 30a and an external fixing jig 31a. External fixing jig 31a
Contacts the copper tape 39 and conducts electricity from this portion, and the ring-shaped terminal 10, the sliding electrode 9 and the ground cable 13 are connected.
The NESA film is brought to the ground potential through a metal frame grounded to the ground potential 14 via the.

Next, a silicate sol was used as a film forming material for forming the second layer, and this solution was supplied to the feeder 2.
4 (pump) to the atomizer 15 at a feed rate of 500 to 1500 cc / min, preferably 1000 cc / min. The film forming material (droplets) misted by the atomizer 15 is -10 to -20 kV with respect to the ground potential, preferably -15 k.
In order to attain V, a voltage is applied to the spray nozzle 15a of the atomizer 15 by an electrostatic charger to which a voltage is supplied from an external power source to charge the film forming material, and electrostatic coating is performed. The coating is performed by moving the nozzle on the X and Y axis rails. As a result, as compared with the conventional spin coating method, a cathode ray tube having a two-layer film having an extremely dense and smooth silicate layer film was obtained. The film strength also increased. Specifically, compared to the spin coating method, the surface roughness is 1/2. The film strength is pencil hardness 9H or more (7-9H in the past). The film uniformity is improved (the film unevenness in the central portion is eliminated. Was done)

Further, when applying the same liquid, the cathode ray tube fixed to the support is rotated, and when a preset rotation speed, for example, 200 rpm is reached, the spray nozzle 15a is operated while performing electrostatic application. The face plate 4a is gradually moved from the center toward the end. As a result, the uniformity of the surface coating was further improved. The nozzle moving speed at this time varies depending on the liquid physical properties such as the viscosity of the coating solution, but it is desirable to move the nozzle in one direction at a moving speed of about 5 cm per second and gradually decrease the speed as it approaches the end. By doing so, a dense and uniform surface coating can be formed as in the case of Examples 1 to 3. In addition, this low-reflection / antistatic film (NESA
When a cathode ray tube is manufactured using a face plate with a film), the NESA film, which is a transparent conductive film, can be set to the ground potential, and an electric attraction to the sprayed droplets can be exerted. As a result, the surface coating is dense and uniform with low reflection.
A completed sphere of a cathode ray tube having excellent antistatic properties can be obtained.

Example 5. Another embodiment according to the present invention will be described. In this embodiment, a face plate 4 having a NESA film previously formed on the surface thereof is produced by the apparatus shown in FIG.
The cathode ray tube of a is used to further form a second layer coating. First, NESA on the surface beforehand
A cathode ray tube is produced using the face plate 4a with the film. Then, the cathode ray tube is attached to the support base 2 of the cathode ray tube holding portion 11 so that the face plate surface faces upward, and as shown in FIG. 5, on the NESA film other than the display screen portion of the face plate 4a of the completed sphere ( A copper tape 36 is attached between the anode button 5 and the case of this embodiment). The NESA film thus conducted to the anode button 5 is electrically connected to the rotating device 12 and grounded to the ground potential 14 via the ring-shaped terminal 10, the sliding electrode 9 and the ground cable 13.

Alkyl silicate 1 is used as a film forming material.
A solution was prepared by mixing 00 g with 40 cc of ethyl alcohol and 60 g of methyl ethyl ketone (MEK). This solution is sent to the atomizer 15 through a movable pipe at a liquid feed rate of 500 to 1500 cc / min, preferably 1000 cc / min by a feeder 24 (pump). The film-forming material (droplets) misted by the atomizer 15 is -10 kV to -ground potential.
A voltage is applied to the spray nozzle 15a of the atomizer 15 by an electrostatic charger to which a voltage is supplied from an external power source so that the voltage becomes 20 kV, preferably -15 kV, and the film forming material is charged to perform electrostatic coating. . For electrostatic coating, the nozzle 15a is X,
Move on the Y-axis rail. As a result, an extremely dense and smooth silicate film was obtained as compared with the conventional spin coating method. The film strength also increased. Specifically, the same effect as in the case of Example 1 was obtained.

When forming the second layer coating, it is also possible to rotate the cathode ray tube fixed to the support base 2 by the rotating device 12 and then perform electrostatic coating. When reaching a preset rotation speed, for example, 200 rpm, the spray nozzle 15a is gradually moved from the center to the end of the face plate 4a while performing electrostatic coating. As a result, the uniformity of the surface coating was further improved. The nozzle moving speed at this time varies depending on the liquid properties such as the viscosity of the coating solution, but it is moved in one direction at an initial speed of about 5 cm per second, and gradually decreases as it approaches the end of the face plate. Is desirable. This is because the speed of the end portion is higher than that of the central portion because the cathode ray tube is rotating, so the moving speed of the spray nozzle 15a is slowed. By doing so, uneven coating on the surface can be eliminated, and a dense and uniform surface coating can be formed. As a result, a good cathode ray tube with a low reflection / antistatic film can be obtained.

Example 6. A cathode ray tube having a two-layered surface coating, which is another embodiment of the present invention, will be described. When forming two or more layers of coating on the surface of the cathode ray tube, first form a coating having electrical conductivity on the first layer, then set the first layer to ground potential and electrostatically coat the second and subsequent layers. To do. Specifically, in order to form the first layer, which is a conductive coating, on the face plate 4 of the cathode ray tube 3, fine particles of indium oxide having an average particle diameter of 10 nm are used as a coating forming material. In this example, since a surface coating consisting of two layers is formed, two types of coating forming materials are used. Therefore, the film forming material supply and spray portion of FIG. 1 replaces the device of FIG. The cathode ray tube 3 is set in the apparatus shown in FIG. 1, and a charge of −10 kV is applied to the film forming material composed of fine particles of indium oxide sent to the atomizer 41 (shown in FIG. 6) by the electrostatic charger 16. The cathode ray tube 3 is rotated to perform electrostatic coating.

Next, the step of forming the second layer film on the first layer film will be described. A silicate sol solution is used as the film forming material for the second layer. Since the first-layer coating is conductive, it can be grounded via the anode button, and the same method as that for the first-layer coating can be used to form the second-layer coating. However, as for the film forming material for the first and second layers, as shown in FIG. 6, a feeder for the first and second layers is prepared so that each solution can be applied from each nozzle. There is.

Although one example of the film forming material for forming the first and second layers has been described above, the first layer film when forming two or more layers is at least indium oxide, tin oxide and zinc oxide. It suffices that the fine particles contain one kind as a main component, and the fine particles are used as powder, and electrostatic coating is performed by an atomizer or the like.

The following materials can be used as the film forming material for the first and second layers. For example, in order to form the first layer which is a conductive film, fine particles of zinc oxide having an average particle diameter of 15 nm are dispersed in an ethyl silicate solution, and electrostatic coating is performed using this solution. Next, an alkyl silicate is used as a film forming material for the second layer, and electrostatic coating is performed on the film for the first layer to form a film for the second layer, thereby forming a cathode wire having a dense and uniform surface film. You can get a tube. An example of the film forming material used for the first and second layers is shown above.
The layer film may be electrostatically coated using a coating solution in which fine particles of tin oxide, indium oxide, and zinc oxide are dispersed in an organic solvent or a solvent containing ethyl silicate as a main component.

Further, the following are examples of the film forming material used for the cathode ray tube having the two-layer film.
First, in order to form the first layer which is a conductive film, 10
Indium chloride and stannous chloride were used in 00 cc of distilled water, and 25.0 g and 1.2 g of each were mixed so that the relation thereof was Sn / In = 0.05, to prepare a coating solution. Using this solution, the surface coating of the first layer is electrostatically coated. Then, heat treatment is performed at 200 ° C. in the air atmosphere to crystallize. Then, the alkyl silicate solution is used to perform electrostatic coating to form a second-layer coating. In this way, a cathode ray tube in which a two-layer film is formed on the face plate can be manufactured.

An example of the film forming material in the case of forming a film consisting of two layers as described above has been described above. As the constitution of the first layer, one of tin oxide, indium oxide and zinc oxide by thermal decomposition treatment is used. Electrostatic coating may be performed using a coating solution having a composition containing at least one of the main components. The reason why the coating solution as described above is used is that an oxide is used in order to have conductivity, and since it is used in a display screen, it must be transparent.

The average particle size of the fine particles of the film forming material used in this example is preferably 200 Å (angstrom) or less. This is because a film having a haze (cloudiness value) of 1% or less can be obtained when the average particle size of the fine particle powder is 200 Å or less. When the haze (cloudiness value) is 1% or less, the transparency of the display screen can be secured.

The film-forming materials used in Examples 1 to 6 were:
Boiling point is above 100 ℃ and below 160 ℃, surface tension is 25dyne
It is desirable to satisfy the conditions that the viscosity is 2 / cm or less and the viscosity is 2 cps or less. If these values are satisfied, a uniform film can be formed. Incidentally, in Examples 1 to 6, mainly a single layer film.
Although the case of the layer film has been described, it goes without saying that the method for forming a surface coating according to the present invention can be applied to the case where a film structure having two or more layers is obtained. Further, although the potentials of the metal back and the black matrix are set to the ground potential in the embodiment, a certain amount of potential may be given depending on the charging tendency of dust or the like in order to prevent the dust or the like from adhering. For example, if dust such as fiber dust generated from the surroundings is likely to be positively charged, a potential of about +100 V may be applied to the metal back and the black matrix.

Further, in the embodiment, the case where the face plate is placed on the rotating device with the face facing upward has been described. However, the face plate is not limited to facing upward, and the atomizer is provided at a position facing the face plate. If installed, the face plate may be fixed in a horizontal, downward, diagonal, or other orientation as shown in FIG.
By tilting the face plate sideways, downward, or diagonally, the excess solution drops down, and it is possible to prevent dust and excess liquid from reattaching to the face plate during film formation. Although FIG. 10 shows the positional relationship between the nozzle and the cathode ray tube, the same positional relationship can be applied to the case of the face plate alone. Although other parts such as a method for fixing the cathode ray tube are omitted, FIG.
The configuration of the other portions is not particularly limited as long as the positional relationship shown in 0 is obtained.

[0071]

According to the apparatus for forming a surface coating film of a cathode ray tube by the electrostatic coating method according to the first invention, the conductive film provided on the inner surface of the face plate of the cathode ray tube is set to the predetermined first potential. However, by setting the film forming material sprayed on the face plate to a predetermined second potential, an electric attractive force can be generated between the face plate and the film forming material. It is possible to form a film on the outer surface of the face plate, and it is possible to form a dense and smooth surface film with improved film strength.

According to the apparatus for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the second aspect of the invention, since the first potential setting means comes into contact with the anode button of the cathode ray tube, it is formed on the inner surface of the face plate. The conductive film can be set to a predetermined first potential, and the surface coating can be formed by the electrostatic coating method. According to the apparatus for forming a surface coating of a cathode ray tube by the electrostatic coating method according to the third aspect of the invention, the first potential setting means comes into contact with the conductive film provided on the inner surface of the face plate alone, so that the cathode ray tube is constructed. The face plate itself can be set to a predetermined first potential.

According to the surface coating film forming apparatus by the electrostatic coating method according to the fourth aspect of the present invention, the coating film forming material is coated while rotating the cathode ray tube held by the holding means at a predetermined speed by the rotating means. By doing so, a surface coating having a uniform film thickness can be formed on the surface of the face plate. According to the surface coating film forming apparatus by the electrostatic coating method of the fifth invention, the spraying means is moved on the outer surface of the face plate to spray the film forming material, so that the outer surface of the face plate is coated uniformly. The forming material can be applied,
A surface coating having a uniform film thickness can be obtained.

According to the surface coating film forming apparatus by the electrostatic coating method according to the sixth aspect of the present invention, the sprayed coating film forming material can be formed by setting the explosion-proof band attached to the cathode ray tube to the predetermined third potential. Since the film-forming material does not adhere to the explosion-proof band and the film-forming material does not scatter on parts other than the face plate, the efficiency of use of the film-forming material is improved. Further, since wasted droplets can be reduced, it is possible to suppress overspray which is a source of dust generation. Furthermore, since dust can be reduced, it is possible to prevent floating dust from being taken into the spray droplets and causing the surface coating to have a non-uniform thickness.

According to the method of forming a surface coating by the electrostatic coating method according to the seventh aspect of the invention, the conductive film provided on the inner surface of the face plate of the cathode ray tube is set to a predetermined first potential, and the outer surface of the face plate is set. The film-forming material that forms a film on the surface was charged to a predetermined second potential, and was sprayed on the face plate to be charged with the metal back and the black matrix corresponding to the conductive film provided on the inner surface of the face plate. An electric attractive force acts between the liquid droplets and a flat and dense film can be formed on the outer surface of the face plate.

According to the method for forming a surface coating by the electrostatic coating method according to the eighth aspect of the present invention, the face plate is rotated at a predetermined speed and is moved from the central portion of the outer surface of the face plate to the end portion to form the coating. By spraying the material, a surface coating having a uniform film thickness can be formed. According to the method for forming a surface coating by the electrostatic coating method according to the ninth aspect of the invention, the face plate is rotated at a predetermined speed, and the moving speed is reduced from the central portion to the end portion of the outer surface of the face plate. However, by spraying the film-forming material, it is possible to cope with the change in speed from the central part to the end part on the outer surface of the rotating face plate, and it is possible to form a surface film with a uniform film thickness. is there.

According to the method of forming a surface coating by the electrostatic coating method according to the tenth aspect of the invention, the first surface coating is formed by forming the electrically conductive surface coating as the first coating. Since it is possible to set the first potential of the above, it is possible to form the second layer coating on the first layer coating by the electrostatic coating method. According to the method for forming a surface coating by the electrostatic coating method according to the eleventh aspect of the present invention, the first coating forming material containing fine particles containing at least one of tin oxide, indium oxide, and zinc oxide is used as a static coating material. By conducting electrocoating, a conductive coating can be formed,
If the face plate is set to a predetermined first potential, the second coating film can be formed on the first coating film by the electrostatic coating method.

According to the method of manufacturing a surface coat forming type cathode ray tube according to the twelfth aspect of the invention, a coat is formed by dispersing fine particles containing at least one of tin oxide, indium oxide and zinc oxide in an organic solvent. If a face plate is set to a predetermined first potential by forming a conductive coating as a first layer using a material, a second layer is formed on the first coating by electrostatic coating. A coating can be formed. According to the method for forming a surface coating film by the electrostatic coating method according to the thirteenth invention, by forming the surface coating film by using the coating film forming material composed of fine particles having an average particle diameter of 200 Å (angstrom), the haze ( A film having a haze value of 1% or less can be obtained, and transparency as a display screen can be secured.

According to the method for forming a surface coating by the electrostatic coating method according to the fourteenth aspect, at least one of tin oxide, indium oxide, and zinc oxide is heat-treated after electrostatically coating the first layer coating. By using the first film forming material that changes to a composition containing seeds as a component, it is possible to form a film that is electrically conductive and that maintains transparency as a display screen. According to the method for forming a surface coating by the electrostatic coating method according to the fifteenth invention, the boiling point is 100 ° C. or higher and 160 ° C. or lower,
By using a film forming material having a surface tension of 25 dyne / cm or less and a viscosity of 2 cps or less, it becomes possible to form a surface film having a uniform film thickness.

According to the method for forming a surface coating by the electrostatic coating method according to the sixteenth aspect of the present invention, the electrodes are provided in advance on the portion other than the image display surface of the face plate, so that the first
Even if a non-conductive coating is formed on the layer, the electrode provided in advance and the coating on the first layer are in contact with each other. Therefore, by setting the electrode to a predetermined first potential, two layers are formed. The coating after the eyes can be formed by an electrostatic coating method. According to the method of forming a surface coating by the electrostatic coating method according to the seventeenth invention, after forming the coating of the first layer, the electrode is provided on the portion other than the image display surface of the face plate, thereby forming the first layer. Since the coating can be set to the predetermined first potential, the second coating can be formed by using the electrostatic coating method.

According to the method of forming a surface coating of a cathode ray tube by the electrostatic coating method according to the eighteenth invention, a waste film forming material other than a surface coating formed on the image display surface of the face plate is used as the face plate. Since it is prevented from adhering to the surface, it is possible to prevent dust and extra liquid from re-adhering to the display surface during film formation during electrostatic coating. According to the method for forming a surface coating film of a cathode ray tube by the electrostatic coating method according to the nineteenth invention, the sprayed coating film forming material can be obtained by setting the explosion-proof band attached to the cathode ray tube at a predetermined third potential. Since the film-forming material does not adhere to the explosion-proof band and the film-forming material does not scatter on parts other than the face plate, the efficiency of use of the film-forming material is improved. Further, since wasted droplets can be reduced, it is possible to suppress overspray which is a source of dust generation. Furthermore, since the amount of dust can be reduced, it is possible to prevent floating dust from being taken into the spray droplets to prevent the film thickness of the surface coating from becoming uneven, and it is possible to form an optimum surface coating.

[Brief description of drawings]

FIG. 1 is a surface film forming apparatus for a cathode ray tube according to the present invention.

FIG. 2 is a view showing a crimping portion of a cathode ray tube and a holding means.

FIG. 3 is an apparatus for forming a surface film on a face plate which constitutes a cathode ray tube according to the present invention.

FIG. 4 is a view showing a face plate alone.

FIG. 5 is a diagram showing an electrode connecting a portion other than an image display of the cathode ray tube and an anode.

FIG. 6 is a diagram showing a film forming material supply device and an atomizer used for forming a surface film consisting of two layers.

FIG. 7 is an enlarged view of a cross section of a face plate on which a surface coating is formed.

FIG. 8 is a diagram comparing the reflectance of the surface of a cathode ray tube having a surface coating consisting of two layers according to the present invention.

FIG. 9 is a diagram showing a surface film forming apparatus according to another embodiment of the present invention.

FIG. 10 is a diagram showing a positional relationship between a cathode ray tube and a spray nozzle.

[Explanation of symbols]

1. Grounding electrode 2. Support 3. Cathode ray tube
4. Face plate 5. Anode button 6. Explosion-proof band 7. Metal fittings
8. Post 9. Sliding electrode 10. Ring-shaped terminal 11. Holding unit 12. Rotating device 13. Ground cable 14. Ground plane 15. Atomizer 16. Electrostatic charger 17. Connector 18. Movable hanging bracket 19. Y-axis rail 20. X-axis rail 21. Cable 22. Movable piping 23. Power supply 24. Feeder 25. Ground plane 26. Film forming material 27. Black matrix 28. Phosphor 2
9. Metal back 30. Internal fixing jig 31. External fixing jig 32.
Conductive brush 33. Power supply 34. Ground plane 35. Copper tape 3
6. Copper tape 37. Feeder 38. Feeder 39. Copper tape
40. NESA film 41. Atomizer

Front page continuation (72) Inventor Noritsuna Hashimoto 1-1-1, Tsukaguchihonmachi, Amagasaki City, Hyogo Sanryo Electric Co., Ltd. Material and Materials Research Laboratory (72) Inventor Takeyuki Maekawa 8-1-1 Tsukaguchihonmachi, Amagasaki City, Hyogo Prefecture No. 1 Sanryo Electric Co., Ltd. Material Device Research Center

Claims (19)

[Claims] 1. An apparatus for forming a surface coating on a face plate of a cathode ray tube, comprising: first potential setting means for setting a conductive film provided on the inner surface of the face plate to a predetermined first potential; and outside the face plate. Second potential setting means for setting the film forming material sprayed on the surface to a predetermined second electric potential, and the film forming material set to the predetermined second electric potential by the second electric potential setting means to the face. An apparatus for forming a surface coating of a cathode ray tube by an electrostatic coating method, comprising: a spraying unit that sprays onto a plate to form a surface coating having a uniform film thickness. 2. The surface coating by the electrostatic coating method according to claim 1, wherein the first potential setting means sets the face plate to a predetermined first potential through the anode button of the cathode ray tube. Forming equipment. 3. The electrostatic coating method according to claim 1, wherein the first potential setting means sets the conductive film provided on the inner surface of the face plate alone to a predetermined first potential. Surface coating device for cathode ray tube. 4. A face plate of the cathode ray tube is held facing the spraying means, and a rotating means is provided for rotating the held cathode ray tube. The rotating means rotates the cathode ray tube at a predetermined speed, and The apparatus for forming a surface coating of a cathode ray tube by the electrostatic coating method according to any one of claims 1 to 3, wherein the spraying means is moved in a predetermined direction and at a predetermined speed. 5. The surface of the cathode ray tube by the electrostatic coating method according to claim 1, wherein the spraying means moves on the outer surface of the face plate to spray the film forming material. Film forming equipment. 6. A means for setting an explosion-proof band attached to a cathode ray tube to a predetermined third potential which is higher than the second potential and lower than the first potential. 2. A device for forming a surface coating of a cathode ray tube by the electrostatic coating method according to 2. 7. A method for forming a surface coating on a face plate of a cathode ray tube by electrostatic coating, wherein a conductive film provided on the inner surface of the face plate is set to a predetermined first potential, and sprayed on the outer surface of the face plate. A method of forming a surface coating film on a cathode ray tube by an electrostatic coating method, characterized in that the coating film forming material is set to a predetermined second potential and is sprayed on a face plate to form a surface coating film having a uniform thickness. . 8. The electrostatic coating method according to claim 7, wherein the face plate is rotated at a predetermined speed and moved from the center to the end of the outer surface of the face plate to spray the film forming material. Method for forming surface coating by. 9. The cathode ray tube by the electrostatic coating method according to claim 8, wherein the film forming material is sprayed while the moving speed is reduced from the central portion of the outer surface of the face plate toward the end portion. The method for forming a surface coating of. 10. A method for forming a surface coating on a face plate of a cathode ray tube by electrostatic coating, wherein a conductive film provided on the inner surface of the face plate is set to a predetermined first potential and sprayed on the outer surface of the face plate. The first film-forming material is set to a predetermined second potential, and is sprayed onto the face plate to form a conductive first layer film, and further on the first layer film. A method for forming a surface coating of a cathode ray tube by an electrostatic coating method, which comprises spraying a second coating forming material to form a second coating. 11. The cathode ray by the electrostatic coating method according to claim 10, wherein the first film forming material contains fine particles containing at least one of tin oxide, indium oxide, and zinc oxide. Method for forming surface coating on pipe. 12. The first film forming material is characterized in that fine particles containing at least one of tin oxide, indium oxide, and zinc oxide are dispersed in an organic solvent. A method for forming a surface coating of a cathode ray tube by the electrostatic coating method as described above. 13. The surface coating of a cathode ray tube by the electrostatic coating method according to claim 7, wherein the fine particles in the coating forming material have an average particle diameter of 200 Å (angstrom) or less. Method. 14. The first film forming material forming the first layer of the film on the outer surface of the face plate is at least one of tin oxide, indium oxide, and zinc oxide by heat treatment after electrostatically applying the first layer. 11. The method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to claim 10, wherein the composition is changed to a composition containing seeds. 15. The boiling point of the film-forming material is 100 ° C. or higher 1
The temperature is 60 ° C or lower, the surface tension is 25 dyne / cm or lower, and the viscosity is 2 cps or lower.
15. A method for forming a surface coating of a cathode ray tube by the electrostatic coating method according to any one of 1 to 14. 16. A method of forming a surface coating on a face plate of a cathode ray tube by electrostatic coating, wherein an electrode is provided in advance on a portion other than the image display surface of the face plate, and a first layer is formed by a first coating forming material. Form a surface coating,
11. The cathode line by the electrostatic coating method according to claim 10, wherein the electrode is set to a predetermined first potential, and a second surface coating film is further formed by a second film forming material. Method for forming surface coating on pipe. 17. The electrostatic electrode according to claim 16, wherein the electrode is formed on a portion other than the image display surface of the face plate after forming a first surface coating on the surface of the face plate. Method for forming surface coating on cathode ray tube by coating method. 18. A cathode ray by an electrostatic coating method according to claim 7, wherein a film forming material other than a surface film formed on the surface of the face plate is prevented from adhering to the surface of the face plate. Method for forming surface coating on pipe. 19. The electrostatic coating according to claim 10, wherein the explosion-proof band attached to the cathode ray tube is set to a predetermined third potential which is higher than the second potential and lower than the first potential. Method for forming a surface coating on a cathode ray tube by the method.