JP2003217450A - Method of manufacturing cathode ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a coating process without deterioration of the reflecting property of a conductive reflecting coating. <P>SOLUTION: A first coating material constituting the conductive reflecting coating and a second coating material constituting a heat absorbing coating and having a low diffusing speed in a heating process are supplied to a heat source and then the heat source is heated, whereby the first coating material is heated and evaporated to form the conductive reflecting coating on the inner face of a panel. Then, with a vacuum being held, the second coating material is heated and evaporated to form the heat absorbing coating on the surface of the conductive reflecting coating. The use of the second coating material having the low heat diffusing speed prevents the second coating material for being diffused to the side of the conductive reflecting coating by heating treatment in a frit sealing process. Thus, the deterioration of the reflecting property is improved. Two continuous coating processes with vacuum deposition produces less manufacturing processes. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method of manufacturing a cathode ray tube. Specifically, in order to improve the emission brightness of the phosphor film, heat is applied to the surface of the conductive reflection film (metal back film) formed on the inner surface of the panel to reduce the landing deviation of the electron beam due to the thermal expansion of the color selection mask. When the absorbing film is formed, the components of the heat absorbing film are prevented from diffusing into the conductive reflecting film, so that the reduction of the reflectance of the conductive reflecting film can be prevented.

[0002]

2. Description of the Related Art As shown in FIG. 5, a color cathode ray tube has a panel 11 having a phosphor film 14 formed on its inner surface. In addition to the phosphor film 14, a conductive reflection film 15 such as aluminum is formed on the inner surface 11 a of the panel so as to cover the surface of the phosphor film 14.

The phosphor film 14 is formed on the inner surface 11a of the panel.
At a predetermined position of a black matrix film (carbon film) (not shown) formed at a predetermined pitch, red R, green G, and blue B phosphor films 14 of respective colors are formed in a predetermined pattern as shown in FIG. After the formation, an intermediate film (filming film) (not shown) for smoothing the surface is formed.

The conductive reflection film 15 is used to improve the luminous efficiency of the phosphor film 14 and increase the emission brightness thereof. Usually, the conductive reflection film 15 is formed on the surface of the phosphor film 14. The light emitted from the phosphor film 14 is designed to be reflected toward the outer surface (outside) of the panel. Aluminum is usually used as the material of the conductive reflection film 15, and is formed by a vacuum deposition method or the like.

Generally, in a color cathode ray tube, three electron beams emitted from an electron gun (not shown) are color-selected by a color selection mask (aperture grill, shadow mask, etc.) 17, respectively. The phosphor film 14 is made to emit light by colliding with the color phosphor film 14.

At this time, the electron beam is emitted from the color selection mask 17
When the temperature reaches, the color selection mask 17 itself generates heat. In addition to this, radiant heat from the color selection mask 17 is further reflected by the conductive reflection film 15 and reaches the color selection mask 17 again, so that the temperature of the color selection mask 17 is further increased. As a result, the thermal expansion of the color selection mask 17 becomes remarkable, and the landing position of the electron beam (the phosphor film 14) is accompanied with this.
A deviation occurs in the arrival position of the electron beam with respect to (1), which causes a problem such as color deviation.

Therefore, conventionally, in order to reduce the landing deviation of the electron beam, a heat absorption film 16 as shown in FIG. 5 is further formed on the conductive reflection film 15 on the inner surface 11a of the panel, and this heat absorption film 16 is used. The thermal expansion of the color selection mask 17 is suppressed by absorbing the radiant heat from the color selection mask 17.

The conventional heat absorbing film 16 is formed by depositing aluminum on the inner surface 11a of the panel to form the conductive reflecting film 15.
After the formation of. Specifically, the conductive reflection film 15
By dissolving graphite in a solvent and spray-coating it on the inner surface 11a of the panel on which is formed, or by vapor-depositing aluminum again at a higher vacuum pressure than when the conductive reflection film 15 is formed (when aluminum is vapor-deposited), aluminum oxide The heat absorption film 1 is formed by forming the heat absorption film 16 or by vaporizing a blackening material (manganese, tin, etc.) other than aluminum.
Several forming methods such as forming 6 are known.

[0009]

However, in such a conventional manufacturing method, a separate step is required to form the heat absorption film, which causes an increase in cost and also deteriorates productivity. .

As one means for improving productivity without causing an increase in cost, a film forming apparatus (chamber) for forming the conductive reflection film 15 is used as a heat absorption film 16.
It is conceivable that the same chamber is used also for performing the film forming process by using the same chamber. Pure metal is used as the material of the heat absorption film 16 used in this case.

However, when pure metal is used as the material of the heat absorption film 16, if the pure metal is continuously vapor-deposited in the same chamber, the heat diffusion rate of the pure metal is high, so that heat is generated in the conductive reflection film 15. The absorbing film metal diffuses. When the heat absorbing film metal diffuses into the conductive reflective film 15, the conductive reflective film 1
The reflectance of No. 5 decreases, and the emission brightness deteriorates accordingly,
You cannot achieve your initial goals.

In order to solve this problem, after the conductive reflective film 15 is vapor-deposited, the panel 11 is once exposed to the atmosphere and a natural oxide film is formed on the surface of the conductive reflective film 15.
A film forming process using a pure metal in the same chamber can be considered. Conductive reflection film 1 of metal for heat absorption film by natural oxide film
This is because the diffusion into 5 is prevented, the decrease in reflectance can be effectively prevented, and the deterioration in luminance can be improved.

However, in this case, since the chamber once leaks to the atmosphere after the conductive reflection film 15 is formed, it is necessary to evacuate again after the air leaks and perform an exhaust process to obtain a predetermined vacuum degree. Therefore, since this leak treatment is newly added, the number of cathode ray tube manufacturing steps (panel manufacturing step) is increased as in the conventional case, and the working time is increased,
Productivity deteriorates, leading to higher costs.

Therefore, the present invention solves the above-mentioned conventional problems, and proposes a method of manufacturing a cathode ray tube capable of improving the decrease in reflectance of the conductive reflection film without increasing the number of manufacturing steps. Is.

[0015]

In the method of manufacturing a cathode ray tube according to the present invention as set forth in claim 1, the first film material forming the conductive reflection film and the heat absorbing film by the heat process are formed. The second film material having a low diffusion rate is supplied to the heating source, and then the first heating source is heated to heat the first film material.
And, the second film material is heated and evaporated to adhere to the inner surface of the panel to form the conductive reflection film and the heat absorption film.

In this method of manufacturing a cathode ray tube, the first and second film materials, which are heating sources, are continuously heated in a vacuum. The heating is first performed so that the temperature is equal to or higher than the boiling point of the first film material and is equal to or lower than the boiling point of the second film material. As a result, the film material having a lower boiling point under vacuum pressure during vapor deposition, that is, the first film material is evaporated and adheres to the inner surface of the panel (the surface of the phosphor film). A conductive reflective film is formed on the inner surface of the panel by vapor deposition to a predetermined film thickness.

After that, the heating temperature is heated to the boiling point of the second film material or higher. By this heat treatment, the second film material using the high boiling point material is evaporated and the second film material is deposited on the surface of the conductive reflective film formed on the inner surface of the panel.
A heat absorption film is formed on the surface of the conductive reflection film by vapor deposition until the film has a predetermined thickness.

As a result, the conductive reflection film 15 and the heat absorption film can be continuously formed by a single vapor deposition process using the same chamber (film forming apparatus). That is, the atmospheric leak process and the exhaust process can be omitted. After forming these films, a welding process for frit sealing the panel and the funnel is performed.

As the second film material, a material having a low thermal diffusion rate in vacuum is used. Therefore, there is no possibility that part of the second film material will be diffused into the conductive reflective film by the processing heat during the frit sealing process. Even if it diffuses, the amount of diffusion is insignificant and the influence on the reflection characteristics of the conductive reflection film can be ignored. This makes it possible to shorten the film forming process while avoiding the influence on the conductive reflection film. As a result, the deterioration of brightness is improved and the productivity is also improved.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a case in which an embodiment of a method of manufacturing a cathode ray tube according to the present invention is applied to panel manufacturing of a color cathode ray tube will be described in detail with reference to the drawings. FIG. 1 is a side sectional view of a cathode ray tube manufactured by the method of the present invention. In FIG. 1, the cathode ray tube body 10 is composed of a glass panel 11 and a funnel 12. The panel 11 and the funnel 12 are joined so as to be integrated with each other by a sealant (frit) in a state where the opening end faces (seal edge faces) of each other are brought into contact with each other.

At the neck portion of the funnel 12, an electron gun 13 as an emission source of an electron beam is installed, and a panel 11 is provided.
A phosphor film 14, a conductive reflection film (metal back) 15 and a heat absorption film 16 are formed in this order on the inner surface of the.

Inside the cathode ray tube body 10, a color selection mask (aperture grill, shadow mask, etc.) 17 constituting a color selection mechanism is incorporated. The color selection mask 17 has a large number of slits or holes for color selection and is arranged in the cathode ray tube body 10 close to the inner surface of the panel 11. The electron beam emitted from the electron gun 14 reaches the inner surface 11a of the panel 11 through the slits or holes of the color selection mask 17 as shown by the broken line in the figure,
The phosphor film 14 formed there emits light.

FIG. 2 is a schematic view of a vacuum vapor deposition apparatus 30 used when carrying out the manufacturing method of the present invention. In FIG. 2, a frame-shaped panel pedestal 19 is provided above a vacuum chamber (vacuum chamber) 18. On the other hand, as the panel 11, the one already coated with the phosphor film 14 is used, and the phosphor film 14 formed on the panel inner surface 11a is used.
Is placed on the panel pedestal 19 so that it faces downward.

Two heating sources 20A and 20B are provided inside the vacuum chamber 18, in this example, at predetermined positions on the bottom. These first and second heating sources 20A and 20B are
In both cases, when the panel 11 is placed on the panel pedestal 19,
It is arranged so as to face the phosphor film 14 formed on the inner surface of the panel.

Each of the heating sources 20A and 20B has a board (crucible) which is a heater housing having a heater (not shown), and the film material is housed inside the board. First heating source 20
The first film material is stored in A, and the second film material is stored in the second heating source 20B. As the film material will be described later, as a heating method for the heater, a resistance heating method,
An electron beam heating method, a high frequency induction heating method, etc. can be adopted. In the embodiment, the resistance heating method is used. The arrangement and the number of heaters are appropriately set according to the size and shape of the panel 11 which is the film formation target.

The first film material is used to form the conductive reflection film 15, and the second film material is used to form the heat absorption film 16. A metal material having a high light reflectance and a low boiling point is used as the first film material. As the low boiling point metal, for example, aluminum, zinc, manganese, silver and the like are considered, and a material containing at least one of them (a single metal or a plurality of metals) is used. As the second film material, a material having a higher infrared absorptivity than the first film material and a slow thermal diffusion rate due to a thermal process after the vapor deposition step is used.

Therefore, as the second film material, there are considered a case where a metal oxide is used and a case where a composite (mixture) in which a material having a lower boiling point than this metal oxide is added to this metal oxide is used. To be As the metal oxide, for example, chromium, manganese, iron, lead, titanium, tin, nickel and the like are considered, and a material containing at least one of these is used. As the low boiling point material, the above-mentioned materials can be used. In the embodiment, a mixture is used as described later.

Among the above metal oxides, the thermal diffusion rate increases in the order of nickel, iron, titanium, cobalt and chromium. Here, since it is known that chromium oxide has a slower thermal diffusion rate than when chromium alone is used, it can be used as a metal oxide constituting the second film material.

In this embodiment, low boiling point aluminum (cylindrical pellets) having a low boiling point in vacuum is used as the first film material, and thermal diffusion in vacuum is used as the second film material. A mixture of slow iron oxide (eg, Fe ₃ O ₄ ) and a low boiling point material, aluminum, is used. Second
As the film material of (3), a powdery solid body of iron oxide is stored inside a cylindrical pellet of aluminum.

The boiling point of aluminum in vacuum is 98.
It is about 0 ° C., and iron is about 1600 ° C. Conventionally, a mixture of aluminum and chromium is often used as the material for the heat absorption film, but the heat diffusion rate of this chromium and iron in vacuum is based on the heating temperature used during frit sealing. In the case of, the thermal diffusion rate of iron is almost (1/15042) that of chromium.

Next, a method of sequentially forming (evaporating) the conductive reflection film 15 and the heat absorption film 16 on the phosphor film 14 formed on the panel inner surface 11a by using the same vacuum evaporation apparatus 30 will be described. . First, the panel 1 is mounted on the panel cradle 19.
1, the first film material is stored in each heating source 20A in the vacuum chamber 18, and the second film material is stored in the second heating source 20B.

Subsequently, the inside of the vacuum chamber 18 is evacuated by a vacuum pump or the like to reduce the total pressure in the vacuum chamber 18 to a specified vacuum pressure (for example, about 10 −4 Torr). Under this reduced pressure state, the first heating source 20A is operated to heat the aluminum that is the first film material housed in the board.

The heating conditions are divided into preheating and main heating as shown in FIG. Preheating is preheating for the first heating source 20A, and in this example, preheating is performed for a period of 20 seconds. The preheating temperature is a predetermined temperature lower than the boiling temperature of aluminum, and is 500 to 800 in this example.
Preheat at about ℃.

After that, main heating is performed for a predetermined time (for example, 45 seconds). The temperature at the time of main heating is higher than the boiling point of aluminum, which is the first film material, so that it can be sufficiently evaporated, and is equal to or lower than the boiling point of the high-boiling material of the second film material, for example, 1250-250. It is set to 1450 ° C. The time required for the main heating is set according to the film thickness of the conductive reflective film 15.

The conductive reflection film 1 having a predetermined thickness in this way
After forming 5, the second heating source 20B is driven this time to vacuum-deposit the second film material. As described above, a mixture of iron oxide and aluminum is used as the second film material. The heating conditions for the second film material are also divided into preheating and main heating as shown in FIG.

Also in this case, as shown in FIG. 4, preheating is performed for a predetermined time (for example, 20 seconds) to sufficiently heat the board. Then, main heating is performed for a predetermined time (for example, 45 seconds).

The temperature at the time of preheating is lower than the boiling point (about 1600 ° C.) of the iron constituting iron oxide in vacuum at a vacuum degree (for example, 500 to 800 ° C., which is the same as the preheating of the first film material). ) Is set.

On the other hand, the temperature during the main heating is higher than the melting point of iron oxide (for example, 1600 to 1700 ° C.).
Is set to. Iron oxide alone has a high boiling point and is difficult to vaporize by heating. However, when it is used in combination with aluminum, the iron oxide is efficiently heated by the heat conduction from the previously molten aluminum, so that it can be relatively easily evaporated.
The main heating time is about 45 seconds. This main heating time differs depending on the film thickness of the heat absorption film 16 to be deposited.

The second film material is heated according to such a temperature profile to continuously form the heat absorption film 16 on the conductive reflection film 15. After the film forming process is completed, the process proceeds to the frit seal welding process. In this frit sealing process, the melting temperature of glass is 450 ° C.
The sealing treatment of the panel 11 and the funnel 12 is performed under a temperature of about a certain degree.

The glass temperature at the time of frit sealing is also conducted to the panel 11, so that the conductive reflection film 15 and the heat absorption film 16 also rise to the same heating temperature. Therefore, the metal oxide (iron oxide) that is the film material of the heat absorption film 16 tends to diffuse toward the conductive reflection film 15.

However, its thermal diffusion rate is very slow as compared with other high-boiling point metal oxide materials, and it hardly diffuses within the time for frit sealing. In particular, compared with chromium which has been conventionally used as a material for a heat absorption film, the heat diffusion rate of iron in vacuum is 15% higher than that of chromium.
Since it is 1 / 1,000 or less, it can be considered that it hardly diffuses into the conductive reflection film 15.

As a result, it is possible to almost surely prevent the iron component from thermally diffusing into the conductive reflection film 15. As a result of preventing the diffusion of the iron component, the reflection characteristic of the conductive reflection film 15 is not deteriorated by the thermal diffusion. Since the deterioration of the reflection characteristics can be prevented, the emission brightness does not decrease, and it is suitable for application to a high-intensity cathode ray tube. Further, since the atmospheric leak process and the exhaust process can be omitted, the number of film forming steps can be reduced.

In the film forming process according to the present invention described above, the conductive reflection film 15 and the heat absorption film 16 can be sequentially formed on the inner surface 11a of the panel 11 by only one vapor deposition process. Since the film forming process is performed in the same vacuum, the manufacturing process of the cathode ray tube can be simplified. In the present invention, since the vapor deposition process is continuously performed without opening to the atmosphere, the working time of the film forming process in which the conductive reflection film 15 and the heat absorption film 16 are combined can be greatly shortened.

In the above embodiment, the first heating source 2
0A is heat-treated to deposit the first film material on the inner surface of the panel, and then the second heating source 20B is heated to vapor-deposit the second film material on the surface of the conductive reflection film 15. Is.

If the second heating source 20B is preheated during the evaporation of the first film material, the second film material can be evaporated almost at the same time as the completion of the evaporation of the first film material. Therefore, the total film formation time can be shortened as compared with the above case. For example, the total film formation time can be shortened by priming and heating the second film material during the main heating of the first film material (for example, after 20 seconds have elapsed).

In the embodiment described above, separate heating sources 2
0A, 20B were prepared, the film materials corresponding to them were housed, and the heat treatment was separately performed, so that the film formation processing was performed. However, a single heat source was provided and the first and second films were provided. Material can also be stored. In this case, the heating temperature may be adjusted so that the first film material is vapor-deposited first, and then the heating temperature is raised to vapor-deposit the second film material.

[0047]

As described above, according to the method of manufacturing a cathode ray tube according to the present invention, a metal oxide having a slow diffusion rate is formed by a thermal process after forming a conductive reflection film on the inner surface of a panel by using a vacuum deposition method. Is used to form a heat absorption film.

According to this, first, the conductive reflection film and the heat absorption film are formed by continuous film formation processing by vacuum evaporation, so that the film formation processing step is simplified. By the way, in the past, after the conductive reflective film was formed, the panel was once returned to the atmosphere, and then the heat absorption film was formed again by vacuum vapor deposition, so that the number of film formation process steps increased and the film formation It took a lot of time and the work efficiency (productivity) was lowered.

According to the present invention, two kinds of films having different film qualities can be efficiently formed by one vacuum vapor deposition process. Further, even if two kinds of films are formed by one vacuum vapor deposition process as described above, it is possible to almost certainly avoid the influence on the conductive reflection film formed first. That is, since the metal oxide having a slow thermal diffusion rate by the thermal process is used as the second film material, the metal oxide is diffused into the conductive reflection film even by the heating when frit-sealing the panel and the funnel. Can be reliably prevented.

This makes it possible to form, on the inner surface of the panel, a conductive reflection film having excellent reflection characteristics (mirror effect) and a heat absorption film having excellent heat absorption characteristics. Since the conductive reflection film has excellent reflection characteristics, the emission brightness of the phosphor film does not decrease. Therefore, the present invention is suitable for application to a method of manufacturing a cathode ray tube with high brightness.

Further, since the heat absorption property is excellent, the thermal expansion of the color selection mask mounted on the panel can be surely suppressed. As a result, the landing deviation of the electron beam can be reduced, and a cathode ray tube with excellent image quality can be provided.

Further, according to the method of manufacturing a cathode ray tube according to the present invention, the first film material and the second film material are supplied to different heating sources, and the heating sources are individually operated. Thereby, the conductive reflection film and the heat absorption film can be sequentially formed in the same vacuum chamber. This eliminates the need for atmospheric leak processing and exhaust processing, thus simplifying the manufacturing process of the cathode ray tube, and as a result, it is possible to reduce the total time required for film formation, thereby reducing the manufacturing cost of the cathode ray tube. It has features such as.

[Brief description of drawings]

FIG. 1 is a side sectional view of a cathode ray tube manufactured by a manufacturing method of the present invention.

FIG. 2 is a schematic view of a vacuum vapor deposition apparatus used when carrying out the manufacturing method of the present invention.

FIG. 3 shows the heating profile of the first membrane material.

FIG. 4 shows a heating profile for a second membrane material.

FIG. 5 is a sectional view of the panel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Panel, 2 ... Phosphor film, 3 ... Conductive reflection film, 10 ... Cathode ray tube main body, 11 ... Panel, 12 ... Funnel, 13 ...
Electron gun, 14 ... Phosphor film, 15 ... Conductive reflection film, 16 ... Heat absorption film, 17 ... Color selection mask, 18 ... Vacuum tank, 19 ... Panel pedestal, 20A, 20B ... Heater part (heating source)

Claims (9)

[Claims] 1. A method of manufacturing a cathode ray tube, wherein a conductive reflection film and a heat absorption film are formed on a panel inner surface by a vacuum deposition method, wherein a low boiling point first film material constituting the conductive reflection film is used. 1
Of the second heat source, the second film material constituting the heat absorbing film and having a slow thermal diffusion rate by the thermal process is supplied to the second heat source, and then heating the first heat source. By heating and evaporating the first film material to adhere the first film material to the inner surface of the panel, form the conductive reflection film on the surface of the phosphor film, and then include the high boiling point material. A method of manufacturing a cathode ray tube, comprising heating and evaporating a second film material to deposit the second film material on the surface of the conductive reflection film to form a heat absorption film. 2. The method of manufacturing a cathode ray tube according to claim 1, wherein a low boiling point metal having excellent reflection characteristics is used as the first film material. 3. The method of manufacturing a cathode ray tube according to claim 2, wherein at least one of aluminum, zinc, manganese, and silver is used as the first film material. 4. A metal oxide having a higher infrared absorption rate than the first film material and a higher boiling point than the first film material is used as the second film material. The method for manufacturing a cathode ray tube according to claim 1. 5. Manganese, iron, as the metal oxide,
The method of manufacturing a cathode ray tube according to claim 1, wherein the method comprises at least one of lead, titanium, tin, nickel, and chromium. 6. The method of manufacturing a cathode ray tube according to claim 5, wherein a metal oxide having a slower thermal diffusion rate in a vacuum is used among the metal oxides. 7. A metal oxide having a higher infrared absorptivity as the second film material than the first film material and having a higher boiling point than the first film material, and a metal having a lower boiling point than the metal oxide. 5. The method of manufacturing a cathode ray tube according to claim 4, wherein: 8. The metal oxide is at least one of manganese, iron, lead, titanium, tin, nickel and chromium, and the low boiling point metal is at least one of aluminum, zinc, manganese and silver. The method of manufacturing a cathode ray tube according to claim 7, which is used. 9. The electrically conductive reflective film and the thermal conductive film are heated by supplying the first film material and the second film material to the same heating source to heat and evaporate the first and second film materials. The method of manufacturing a cathode ray tube according to claim 1, wherein an absorption film is deposited on the inner surface of the panel.