JPH07169396A - Thin film formation of external surface of cathode-ray tube face plate - Google Patents

Abstract

PURPOSE:To easily form a thin film with sufficient film strength without deteriorating a cathode-ray by carrying out firing by directly radiating infrared rays with specified wavelength and specififed radiation intensity or more to a dryer. CONSTITUTION:A thin film forming apparatus is provided with a circular cathode supporting body 12 which is supported in an upper side open part of a box 11 in the way it can rotate and rotated and moved by a driving apparatus. A hole into which a face plate of a cathode-ray tube 12 can be inserted is formed and a cathode-ray tube 12 is set in the hole in the way the external side of the face plate 1 is set downward and faces to the inside of the box 11 by utilizing the lug plate 14 attached to an explosion preventive band 7 which fastens the side walls of the face plate 1. The cathode-ray tube 13 set in the supporting body 12 is rotated and moved together with the supporting body 12 on the tube axis Z as a rotary center axis. A nozzle 15 to spray a film forming liquid to form a reflection preventing film on the external side of the plate 1 is installed inside the box 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thin film on the outer surface of a cathode ray tube face plate which forms a thin film having an antistatic effect and an antireflection effect on the outer surface of a face plate of a cathode ray tube.

[0002]

2. Description of the Related Art Generally, a cathode ray tube is constructed as shown in FIG.
A phosphor screen 2 is formed on the inner surface of a face plate 1 made of glass, and the phosphor screen 2 is horizontally and vertically scanned by an electron beam emitted from an electron gun 5 arranged in a neck 4 of a funnel 3. , Is formed in a structure for displaying an image.

The cathode ray tube shown in FIG. 2 is a color picture tube, 6 is a shadow mask arranged inside the phosphor screen 2 facing the phosphor screen 2, and 7 is a face plate 1.
It is an explosion-proof band that tightens the side wall of.

In such a cathode ray tube, in which a high voltage is applied to the phosphor screen 2 in order to display a particularly high brightness image, the high voltage is induced on the outer surface of the face plate 1 and charged. If dust or the like adheres to the outer surface of the face plate 1 due to this charging, the image becomes difficult to see. When a human body comes into contact with the outer surface of the face plate 1, it receives an electric shock. Further, since the outer surface of the face plate 1 of the cathode ray tube is generally formed as a mirror surface, external light is reflected on the outer surface of the face plate 1 to deteriorate the contrast of an image viewed through the face plate 1. Especially with computer displays, etc., the screen is often viewed from a short distance,
Reflection of external light promotes eye fatigue.

In order to prevent such charging of the outer surface of the face plate or reflection of external light, it has been conventionally known to form a thin film having an effect of charging and / or antireflection on the outer surface of the face plate. .

As a method for uniformly and inexpensively forming the thin film having the antistatic and antireflection effect, the cathode ray tube is rotated by a method of spraying a film forming liquid on the outer surface of the face plate by a spray method or a spin coating method. While spraying the film forming liquid on the outer surface of the face plate, the film forming liquid applied on the outer surface is uniformly spread by the centrifugal force generated by the rotation of the cathode ray tube, dried, and then baked to form the film. .

Particularly in a two-layer or two-layer or more structured film for the purpose of low reflection, each layer must be an interference film having a different refractive index. In this case, as a method for forming an interference film having a high refractive index, Sn is added to an alcohol solution of ethyl silicate.
In order to disperse a high-refractive-index conductive material such as O ₂ or In ₂ O ₃ or to further improve the contrast of a cathode ray tube, a film forming liquid containing a dye, a pigment or an organic pigment is generally used. Further, as a method of forming an interference film having a low refractive index, a film forming liquid made of an alcohol solution of ethyl silicate is used. The formation of a two-layer or two-layer or more structured film using these film-forming solutions is performed by first applying the film-forming solution from the lowermost layer, drying it, and then firing it at a temperature of about 200 ° C.

In this case, the film strength obtained increases as the firing temperature increases, but when a thin film is formed on the outer surface of the face plate of the completed cathode ray tube, valve cracks occur when the firing temperature is high. Since it is easy and the cathode ray tube characteristics are deteriorated such as deterioration of the cathode of the electron gun, it is necessary to obtain sufficient film strength at a temperature as low as possible.

[0009]

As described above, in order to prevent the charge on the outer surface of the face plate of the cathode ray tube or the reflection of external light from the prior art, the outer surface of the face plate is provided with an effect of charging and / or antireflection. It is known to form a thin film having As a method for uniformly and inexpensively forming a thin film having this antistatic or antireflection effect, a method of spraying a film forming liquid on the outer surface of the face plate by a spray method or a spin coating method while rotating the cathode ray tube There is a method in which a film forming liquid is sprayed on the outer surface of the face plate, uniformly spread by a centrifugal force, dried, and then baked to form the film.

The film strength formed by these methods increases as the baking temperature increases, but when a thin film is formed on the outer surface of the face plate of the completed cathode ray tube, valve cracks occur when the baking temperature is high. In addition, since the cathode ray tube characteristics are deteriorated such as deterioration of the cathode of the electron gun, it is necessary to obtain sufficient film strength at a temperature as low as possible.

The present invention has been made to solve the above problems, and forms a thin film having a sufficient film strength on the outer surface of the face plate of the cathode ray tube without degrading bulb cracks and cathode ray tube characteristics. The purpose is to do.

[0012]

Means for Solving the Problems A film forming liquid is sprayed and applied on the outer surface of a face plate, and the applied film forming liquid is dried to form a dry film, and the dry film is baked to form a face. In the method for forming a thin film on the outer surface of a cathode ray tube face plate in which a thin film is formed on the outer surface of the plate, the dry film is baked by directly irradiating the dry film with infrared rays having a wavelength of 2 to 10 μm and a radiation intensity of 50% or more.

[0013]

As described above, when the dried film obtained by coating and drying the film-forming solution is directly irradiated with infrared rays having a wavelength of 2 to 10 μm and a radiant intensity of 50% or more, the temperature rise rate of the film increases, A thin film having sufficient film strength can be formed without degrading the characteristics of the cathode ray tube such as valve cracks and deterioration of the cathode of the electron gun.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1 shows a thin film forming apparatus for forming a thin film such as an antireflection film on the outer surface of a face plate of a cathode ray tube. This thin film forming apparatus is an apparatus for forming a thin film by a spin coating method, and has a bottomed cylindrical casing 11 provided with a gas discharge port 10 connected to a discharge device (not shown) at the bottom, and this casing. A disk-shaped cathode ray tube support 12 is rotatably supported by the upper opening of the disk 11 and is rotationally driven by a driving device (not shown). The cathode ray tube support 12 has an opening formed in the center thereof, into which the face plate 1 of the cathode ray tube 13 can be inserted, and the cathode ray tube 13 has a face plate 1 in the opening.
The lug plate 14 attached to the explosion-proof band 7 for tightening the side wall of the face plate 1 is used so that its outer surface faces downward and is inside the housing 11. The cathode ray tube 13 attached to the cathode ray tube support 12 is rotationally driven together with the cathode ray tube support 12 so that the tube axis Z becomes the rotation center axis. Further, facing the outer surface of the face plate 1 of the cathode ray tube 13 and inside the housing 11,
A nozzle 15 for spraying a film forming liquid for forming an antireflection film is provided on the outer surface of the face plate 1.

The thin film is formed by this thin film forming apparatus by making the outer surface of the face plate 1 face down into the opening of the cathode ray tube support 12 and inside the housing 11 so that the cathode ray tube 13 is formed.
Mounted, and rotates together with the cathode ray tube support 12. Then, the outer surface of the face plate 1 of the rotating cathode ray tube 13 is sprayed from a nozzle 15 with a film forming liquid in which TiO2 is dispersed as a conductive material in an alcohol solution of ethyl silicate, and the outer surface of the face plate 1 is covered. The film-forming liquid applied to the surface is uniformly spread by the centrifugal force due to the rotation of the cathode ray tube 12 and dried. Next, a film-forming solution consisting of an alcohol solution of ethyl silicate is sprayed and applied onto the dried film, and the applied film-forming solution is uniformly spread by the centrifugal force due to the rotation of the cathode ray tube 12 and dried, A dry film having a two-layer structure is formed. After that, the wavelength of 2
Directly irradiate with infrared rays having a radiation intensity of 50% or more and 10 μm, and heat to about 200 ° C. for firing.

By this calcination, the ethyl silicate of the dried film is decomposed into SiO ₂ and TiO having a high refractive index is formed in the lower layer.
₂ / SiO ₂ , and a two-layer antireflection film made of SiO ₂ having a low refractive index is formed on the upper layer.

As described above, when the antireflection film forming liquid is applied to the outer surface of the face plate 1 of the cathode ray tube 13 and the dried film is directly irradiated with infrared rays having a wavelength of 2 to 10 μm and a radiant intensity of 50% or more, and baked. High efficiency of heat radiation to the dry film is obtained, thereby increasing the film temperature rising speed, effectively heating the dry film, and degrading the cathode ray tube characteristics such as valve crack of the completed cathode ray tube 13 and deterioration of the cathode. The antireflection film having sufficient film strength can be formed on the outer surface of the face plate 1 without causing

As a test of the above-mentioned antireflection film forming method, a film forming liquid in which TiO ₂ is dispersed in an alcohol solution of ethyl silicate is applied to the outer surface of the face plate of the cathode ray tube by spin coating, and only the lower dry film is applied. Of the cathode ray tube having a wavelength of 2 to 10 μm and an emission intensity of 50% or more. In the infrared heating furnace, the formed film was directly irradiated with infrared rays and baked, and the case where the film was put in a hot air heating furnace and baked was compared. The results are shown in FIG.

A curve 17 represents a case where the lower dry film was irradiated with infrared rays, and a curve 18 represents a case where the lower dry film was heated with hot air.
Curve 19 shows the case where the upper dry film is irradiated with infrared rays, and curve 20 shows the case where the upper dry film is heated with hot air.

As can be seen from the curves 19 and 20 in FIG. 3, the outer surface of the face plate is coated with a film forming liquid consisting of an alcohol solution of ethyl silicate to form only a dry film of the upper layer, and is baked to form SiO _2. When an upper layer film made of is formed, there is almost no difference in the temperature rising rate of the film between infrared irradiation and hot air heating. On the other hand, curves 17, 18
As can be seen from the above, when a film forming liquid in which TiO ₂ is dispersed is applied to an alcohol solution of ethyl silicate to form only a lower dry film, and a lower film made of TiO ₂ / SiO ₂ is formed by firing, Infrared irradiation has a much higher heating rate and higher efficiency than hot air heating. It is considered that this is because the radiation efficiency of infrared rays is increased by the added TiO ₂ which is a high refractive material.

Such characteristics can be applied to a high refractive index material such as In ₂ O ₃ and the same effect can be obtained. Further, when a dye, a dye, a pigment, or the like is further included, these materials generally have strong absorption for infrared rays having a wavelength of 2 to 10 μm, and thus the same effect can be obtained.

The upper layer film and the lower layer dry film formed on the outer surface of these face plates were replaced with Lion # 50/5.
As a result of measuring the frictional strength by applying a load of 1 kg to 0 eraser, in Table 1, the case where the appearance does not change is indicated by ○, the case where slight scratches occur is indicated by △, and the case where the film is peeled off is indicated by ×. It was found that the film strength of infrared irradiation was higher than that of heating.

[0024]

[Table 1] That is, after the film forming liquid is applied to the outer surface of the face plate 1 of the cathode ray tube 13 and dried, the dried film has a wavelength of 2 to 2
When infrared rays of 10 μm and radiant intensity of 50% or more are directly radiated and fired, the temperature rise rate of the film is increased, and the dried film is effectively heated and fired, so that the valve crack of the completed cathode ray tube 13 and the cathode of the electron gun An antireflection film having sufficient film strength can be formed on the outer surface of the face plate 1 without causing deterioration of the cathode ray tube characteristics such as deterioration.

In the above embodiment, the case where the antireflection film is formed on the outer surface of the face plate of the cathode ray tube has been described. However, the present invention is an antistatic film or a film having both effects of charging and antireflection. It is also applicable to the case of forming.

[0026]

EFFECT OF THE INVENTION Cathode ray tube for coating a film forming liquid on the outer surface of the face plate and drying it to form a dry film, and baking the dry film to form a thin film on the outer surface of the face plate. In the thin film forming method, when the dry film is directly irradiated with infrared rays having a wavelength of 2 to 10 μm and a radiant intensity of 50% or more and baked, the temperature rising speed of the film is increased, and bulb cracks, deterioration of the cathode of the electron gun, and the like. A thin film having sufficient film strength can be easily formed without deteriorating the characteristics.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a thin film forming apparatus for forming a thin film on an outer surface of a face plate of a cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the effect of the thin film forming method according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a conventional cathode ray tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Face 7 ... Explosion-proof band 10 ... Gas discharge port 11 ... Housing 12 ... Cathode ray tube support 13 ... Cathode ray tube 15 ... Nozzle

Claims (1)

[Claims] 1. An outer surface of a face plate by spraying and applying a film forming liquid on the outer surface of a face plate, drying the applied film forming liquid to form a dry film, and firing the dry film. In the method for forming a thin film on the outer surface of a cathode ray tube face plate for forming a thin film on a cathode, the dry film is directly irradiated with infrared rays having a wavelength of 2 to 10 μm and a radiation intensity of 50% or more, and the dry film is baked. Method for forming thin film on outer surface of tube face plate.