JP3225575B2 - Color cathode ray tube and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube having a face plate having an extraneous light antireflection layer and a method for manufacturing the same, and more particularly, to a color cathode ray tube having an antireflection layer suitable for preventing extraneous light from being reflected on the inner surface of the faceplate. The present invention relates to a color cathode ray tube and a method for manufacturing the same.

[0002]

2. Description of the Related Art A cathode ray tube such as a cathode ray tube usually reflects external light strongly because its face plate surface (image display surface) is in a glossy state, and it is difficult to read an image displayed on the face plate surface. There was a problem.
In particular, recently, in addition to a television receiver, a display device including various kinds of cathode ray tubes has been widely used as a terminal of an information device.
It has been widely used in the field of DT (Visual Display Terminal), and the demand for antireflection has been increasing.

Various measures have been taken to prevent the reflection of extraneous light. For example, a glass surface is etched with hydrofluoric acid (H ₂ SiF ₆ ) or the like, and the surface is deeply etched. 5nm ~ 3000nm, pitch 10nm ~ 200nm
Of which an anti-reflection function is imparted by providing irregularities (US Pat. No. 2,490,662) or an alkoxysilane (Si (O
An alcohol solution of R) ₄ ) (R is an alkyl group) is sprayed onto a glass surface and then fired to form irregularities formed of a SiO ₂ film (Japanese Patent Application Laid-Open No. 61-118932).

In order to prevent reflection of a high-definition display tube or a high-definition television CRT for which high resolution is required, a metal compound or a polymer compound such as MgF ₂ , TiO ₂ , SiO ₂ or the like is used. A method of stacking layers, controlling the thickness and refractive index of the layers with high precision, and weakening reflected light by using light interference has already been put to practical use.

However, all of the above-mentioned methods are anti-reflection methods for the outer surface of the face plate of the cathode ray tube, and if used alone, the influence of extraneous light reflected on the inner surface of the face plate appears strongly on the surface, making it difficult to view an image. May be.

Therefore, it is conceivable to form an antireflection film having the above-mentioned contents on the inner surface of the face plate. However, it is necessary to apply a phosphor on the inner surface of the face plate of the cathode ray tube, and the coating is sufficiently resistant to the influence of this coating. An antireflection layer must be obtained so that there are various problems.
That is, in the method of roughening the inner surface of the face plate by, for example, H ₂ SiF ₆ etching, the obtained rough surface is changed by various chemical treatments at the time of applying the phosphor, or the phosphor cannot be applied smoothly. There is. Also, S
The method of forming an uneven surface by spraying an i (OR) ₄ alcohol solution has a drawback that the phosphor does not adhere well because the surface unevenness is severe. Furthermore, when a metal compound or a polymer compound is laminated, it is generally formed by vacuum evaporation or sputtering. However, the film quality is extremely liable to change, and the reflectance is greatly increased by heat treatment or chemical treatment at the time of applying the phosphor. There is a problem that.

In order to solve such a problem, the inventors have previously proposed a cathode ray tube having a film exhibiting an anti-reflection characteristic of extraneous light on the inner surface of the face plate and a method of manufacturing the same.

[0008]

According to the above-mentioned technique proposed by the present inventors, as shown in FIG. 5, an S 3 in which SiO ₂ is added to the inner surface 3 ′ of a face plate 3 of a color cathode ray tube.
After applying an alcohol solution of i (OR) ₄ and firing,
An anti-reflection layer 5 made of a SiO ₂ film is formed, and a black matrix graphite layer 4 (hereinafter, referred to as a BM layer) is formed thereon.
And a technique of forming the phosphor layer 6.

[0009] However, the above technique has the following problems. That is, (1) In this case, as shown in FIG. 5, since the antireflection layer 5 is provided between the inner surface 3 'of the face plate 3 and the BM layer 4, the beam holes 4' of the BM layer are accurately cleaned. Inability to open in shape. In particular, in recent years, there has been a growing demand for fine-pitch, ultra-high-definition color cathode-ray tubes with a small beam diameter, but they cannot respond to this.

(2) As shown in FIG. 5, since the anti-reflection layer 5 is provided between the inner surface 3 'of the face plate 3 and the BM layer 4, the BM is generated by the diffuse reflection light from the anti-reflection layer 5. Layer 4 looks slightly white. The original role of the BM is to improve the contrast, and it must appear as black as possible.

(3) Further, when the BM layer 4 is applied, it is necessary to chemically clean the inner surface 3 'of the face plate 3 which is the application surface, for example, with hydrofluoric acid or alkali. When the antireflection film 5 is provided, the antireflection film 5 may be deteriorated by an acid or an alkali, and there is a restriction that sufficient cleaning cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art, to form a beam hole in the BM layer in a simple form, to provide an image with excellent contrast, A color cathode ray tube having an anti-reflection layer having an anti-reflection layer having an extraneous light anti-reflection property on the inner surface of a face plate, which can withstand various treatments at the time of body application, does not adversely affect the phosphor application, and has a method of manufacturing the same. To provide.

[0013]

Above object In order to achieve the above, in the production of color picture tubes having an antireflection layer on the face plate surface, Si was added SiO ₂ fine particles after forming the BM layer on the face plate surface (OR) _This can be achieved by applying an alcohol solution of No. ₄ to form a color cathode-ray tube in which an anti-reflection layer containing SiO ₂ fine particles is formed on at least the face plate surface where no BM layer is present.

More specifically, in the process of forming a BM and a phosphor layer of an ordinary color CRT, first,
After cleaning the inner surface of the face plate with hydrofluoric acid, etc.
A BM layer is formed by an ordinary method, and then an alcohol solution of Si (OR) ₄ containing fine particles of SiO ₂ is applied,
And dried at a temperature, to fix this and SiO ₂ fine particles S of
An anti-reflection layer composed of an iO ₂ binder is formed, and finally, a phosphor layer is applied by an ordinary method.

[0015]

According to the color cathode ray tube and the method of manufacturing the same according to the present invention, since the antireflection layer is formed after the BM layer is formed on the inner surface of the face plate, the BM layer is formed with high precision, and the shape of the beam hole is improved. Quality such as cutting and uniformity is improved. Further, since there is no anti-reflection diffusion layer between the inner surface of the face plate and the BM layer, the BM original black color can be maintained.

The area occupied by the BM layer is about 20% of the entire inner surface of the face plate, and the corresponding antireflection effect is lost. However, the remaining 80% of the area is substantially coated with the antireflection layer. There is almost no effect.

In addition, SiO ₂ forming an anti-reflection layer
Are fine particles having a particle size of 0.5 μm or less, and the particle size of the phosphor applied thereon is about 10 μm, so that there is no effect on the application accuracy of the phosphor. Further, the antireflection layer is made of SiO ₂ and has a transmittance of 90%.
% Or more (equivalent to glass or more), it does not affect the luminance of the phosphor, but rather increases the ratio of the emission of the phosphor to the front surface due to the anti-reflection effect, thereby improving the luminance.

When a BM layer is applied, the accuracy of the finished BM is greatly affected by the cleanliness of the base. In the method proposed in the above prior art, a strong cleaning agent such as hydrofluoric acid or caustic soda could not be used because the base was an anti-reflection film, but in the case of the method of the present invention, they can be used. Therefore, very beautiful BM
Layers can be obtained.

Further, the antireflection layer formed on the inner surface of the face plate as described above has a particle size of 0.5 μm or less.
The phosphor coated onto because antireflective layer surface which consists of SiO ₂ of the microparticles can be carried out easily in. In addition, SiO
_Since the fine particles of No. ₂ are firmly fixed by the SiO ₂ binder formed by decomposition of Si (OR) ₄ , they have excellent chemical, mechanical, and thermal strengths, and have various chemical treatments.
Shows excellent durability against heat treatment.

[0020]

The color cathode ray tube and the method of manufacturing the same according to the present invention will be specifically described below with reference to examples.

First, FIG. 2 is a partial cross-sectional view showing a schematic structure of a color cathode ray tube according to the present invention, and FIG. 3 is a view for explaining an anti-reflection mechanism in the anti-reflection layer shown in FIG. Now, when the external light L is incident on the outer surface of the face plate 3, part of the light is reflected on the outer surface to become reflected light L ₁ , and part of the light becomes incident light L _{2 on} the inner surface of the face plate 3. Here, when the antireflection layer 2 does not exist, L ₂ is reflected on the E surface and emerges again on the outer surface, but between the E and D on the inner surface of the face plate 3, the SiO ₂ fine particles 7 and the SiO ₂ fine particles 7 are fixed. Since it is filled with the binder 8 and its refractive index is almost equal to the refractive index of glass (SiO ₂ ) of about 1.47, the light passes through the E plane and becomes incident light L ₃ due to the interference action. If the D surface is a smooth inner surface, L ₃ is reflected on the D surface, but there are fine irregularities on the hemisphere inside the D surface, and the D 3
Since the layer inside the surface is a layer whose refractive index continuously decreases gradually, the light of L ₃ undergoes re-interference by this layer, passes through this layer, and becomes incident light L _4. Proceed further inside. Note that the refractive index of the fine irregularities is the volume fraction of SiO ₂ , that is, the thickness of the plate having a small thickness cut by a plane parallel to both end surfaces A and D of the irregularities, with respect to the entire volume of the plate. It changes continuously according to the volume ratio of the SiO ₂ portion.

Now, let the refractive index between E and D of the antireflection layer 2 be ng, the refractive index on the C surface slightly inside the D surface be n ₂ , and the refractive index on the B surface slightly outside the A surface be _ng . n ₁ , assuming that the refractive index of the internal space inside the A-plane is n ₀ , the condition under which the reflectance R at the antireflection layer is minimized is expressed by the following equation.

[0023]

(Equation 1) Further, from the above equation (1), anti-reflection performance can be obtained when the condition represented by the following equation is satisfied.

[0024]

(Equation 2) Here, the value of n ₂ / n ₁ is determined by the shape of the irregularities. However, as described above, an alcohol solution of Si (OR) ₄ to which SiO ₂ fine particles are added is applied and baked, whereby the above equation is approximately obtained. Satisfactory irregularities will be formed.

Next, a method for manufacturing a color CRT according to the present invention will be described with reference to FIGS.

First, ethyl silicate (Si (OC ₂ H ₅ )
₄ ) is dissolved in ethanol, and H
_A solution is prepared by adding ₂ O and HNO ₃ as a catalyst, and SiO ₂ fine particles sized to a predetermined particle size (for example, 0.2 ± 0.01 μm) are further added to the solution, and then sufficient dispersion is obtained. Next, the pH of the solution was adjusted. On the other hand, after cleaning the inner surface 3 'of the face plate 3 of the color cathode ray tube 1 with 5% hydrofluoric acid and caustic soda, hot pure water at 70 to 80 ° C. by a predetermined procedure, a BM layer 4 is formed by a predetermined method, and thereafter, The above-mentioned solution for forming an antireflection layer was dropped on the surface 3 ', and was applied uniformly by spinning. In order to improve the wettability of the surface 3 'to be coated and to prevent the BM layer 4 from being deteriorated, a precoat film is provided prior to the spinning application, or SiO is used to complete the selective application of the antireflection layer 2 more completely. _A method of applying a mixture of a Si (OR) ₄ solution to which fine particles are added and a photosensitive resin and exposing the mixture to form an anti-reflection layer 2 only on necessary portions can also be adopted. Next, the coating layers 2 and 4 were dried and fixed at a temperature of about 100 ° C. using an infrared lamp, and after a certain degree of hydrolysis had reached a stable state, by a predetermined method,
The phosphor layer 6 was formed thereon.

Through the above steps, the BM layer 4 and the phosphor layer 6 could be formed very uniformly.

The drying, fixing and disassembly can be carried out in accordance with the manufacturing process of the color CRT 1. Also, in the frit baking and exhaust processes, which are the subsequent processes of manufacturing the color cathode-ray tube 1, the temperature is usually about 400 ° C.
Since the temperature is raised to the front and rear, the coating layers 2, 4, and 6 become sufficiently strong, and the adhesion is sufficiently performed.

The internal reflectance of the face plate of the color CRT obtained as described above was measured using a Hitachi U-3200 type spectrophotometer, and the results shown in FIG. 4 were obtained. The cathode ray tube used for the measurement was provided with an antireflection film on the outer surface of the face plate so that only the internal reflectance of the face plate could be measured. FIG.
A is a color CRT without an internal anti-reflection layer, B
Is a color cathode ray tube having an inner anti-reflection layer containing fine particles of SiO _{2 having a} particle size of 0.3 μm, and C is a SiO ₂ particle having a particle size of 0.5 μm.
FIG. 3 shows a regular reflectance curve of a color CRT having an internal antireflection layer containing fine particles. From these results, A is 1.74 as an integrated value in the wavelength range of 400 to 700 nm.
%, B is 0.44%, and C is 0.41%. It can be seen that B and C show a remarkable reflection reduction effect with respect to A.
The reflectance of about 0.4% is a value that is hardly noticeable visually.

In the case of B and C with respect to A, the color of BM was also black and remained clearly. When the color CRT was illuminated, the contrast was improved by 20% by the antireflection effect. Further, the beam hole diameter accuracy of the BM layer was good, and the focus characteristics were also good.

[0031]

As described above, by applying the method for manufacturing a color cathode ray tube according to the present invention to obtain a color cathode ray tube having the structure of the present invention, the problems of the prior art can be solved. The beam hole of the layer can be opened in a clean form, it can give an image with excellent contrast, can withstand various treatments at the time of phosphor application, does not adversely affect the phosphor application, and is sufficiently satisfactory The external light reflection preventing property on the inner surface of the face plate was obtained.

Further, by applying the method for manufacturing a color cathode ray tube according to the present invention, the antireflection layer can be easily formed by slightly changing the conventional procedure for manufacturing a color cathode ray tube, and has an antireflection characteristic. Color cathode ray tubes can now be obtained at low manufacturing costs.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a main part of a face plate of a color cathode ray tube according to the present invention.

FIG. 2 is a partial sectional view showing a schematic configuration of a color cathode ray tube according to the present invention.

FIG. 3 is a view for explaining an anti-reflection mechanism in the anti-reflection layer shown in FIG. 2;

FIG. 4 is a diagram showing a comparison of a regular reflectance curve on the inner surface of a face plate of a color CRT.

FIG. 5 is an enlarged view of a main part of a face plate of a color cathode ray tube having a conventional configuration.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Color CRT, 2 ... Anti-reflection layer, 3 ... Face plate, 3 '... Inner face plate, 4 ... BM layer,
4 ': Beam hole of BM layer; 6: Phosphor layer; 7: SiO ₂
Fine particles, 8: SiO ₂ binder.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-99945 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 29/88 H01J 9/20

Claims (3)

(57) [Claims] 1. A color cathode ray tube having an antireflection layer provided on an inner surface of a face plate, wherein the antireflection layer is provided.
Formed by Si _{(OR) 4} a SiO ₂ fine particles
It is fixed by SiO ₂ binder, the SiO ₂
Particle size of the fine particles is 0.2 to 0.5 [mu] m, and, prior to
The antireflection layer is between the phosphor layer and the face plate,
A color CRT characterized by being present on a black matrix layer. 2. A method of manufacturing a color cathode-ray tube having an anti-reflection layer on the face plate surface, Si was added SiO ₂ fine particles after forming the black matrix layer on the face plate surface (OR) 4 _(R is an alkyl group A) forming an antireflection layer containing fine particles of SiO ₂ on at least the face plate surface on which no black matrix layer is present, by applying the alcohol solution of (a). 3. A color cathode ray tube according to claim 1, wherein the SiO ₂ fine particles of said antireflection layer have a size of 0.3 to 0.5 μm.