JPH07134956A - Cathode-ray tube and its manufacture - Google Patents

Abstract

PURPOSE:To simultaneously satisfy the demands of an excellent reflection preventive function and a high contrast and further provide a charging preventive function by forming a charge preventive film having a light absorptive function on the external face of a panel and forming a reflection preventive film thereon. CONSTITUTION:The peripheral apparatus of a cathode-ray tube is composed of a panel 10, a funnel 20, and a neck 30. A charging preventive film 80 is formed on the external surface of the panel 10, wherein the film has a light absorptive function and is formed by applying a solution prepared by mixing at least either one of an organic dye and a pigment with a mixed solution of at least one selected from tin oxide, indium oxide, titanium oxide, and antimony oxide and an alcohol solution of ethyl silicate. A reflection preventive film 90 is formed on the film, wherein the film is formed by applying a solution prepared by mixing super fine particles of at least one of silicon oxide and magnesium fluoride with an alcohol solution of at least one kind of alcohol selected from respective alkoxides of silicon, zinc, and titanium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube and a method for manufacturing the same, and more particularly to a cathode ray tube having functions of preventing reflection of external light on an image display surface, enhancing contrast, and preventing surface charging due to electrostatic induction. And its manufacturing method.

[0002]

2. Description of the Related Art Cathode ray tubes known as CDT, CPT, etc., tend to reflect outside light because the surface of the panel which is the image display surface (hereinafter referred to as the panel surface) is generally in a glossy state. There is a problem that the image displayed on the panel surface becomes difficult to read.

Particularly, recently, a display device provided with a cathode ray tube as a terminal of information equipment in addition to a television receiver has been widely used and has been taken up as a problem of the working environment of an operator. Preventive measures are strongly required.

At the same time, with the spread of so-called reinforced cathode ray tubes, the protective glass is not required on the panel surface of the cathode ray tube, and the panel is exposed directly to the outside air. However, there is also a problem that the user is shocked and the user is shocked, or dust in the atmosphere is adsorbed to reduce the visibility of the display image.

As a measure for solving the above problems,
Various types have been proposed in which an antireflection film or a transparent conductive film is attached to the outer surface of the panel.

As an antireflection film of this kind, Japanese Patent Laid-Open No. 63-
In the cathode ray tube disclosed in Japanese Patent No. 193101, an alcohol solution of Si (OR) ₄ (R is an alkyl group) to which fine particles of silicon oxide (SiO ₂ ) are added is applied and baked on the surface of a glass body forming a panel. However, it has an antireflection film that has fine and uniform irregularities on the surface and utilizes the interference of light due to the continuous change of the refractive index.

Further, in the cathode ray tube disclosed in JP-A-1-154445, a transparent conductive film is formed on the antireflection film to have both antireflection performance and antistatic performance.

Further, Japanese Patent Laid-Open No. 63-30346 discloses a method of forming a colored film from a solution containing an organic dye and ethyl silicate on a glass surface constituting a panel of a cathode ray tube.

Then, based on the above-mentioned method for forming a colored coating film, a colored transparent conductive film containing an organic dye is formed in a transparent conductive film which is an antistatic film to form a cathode ray tube having a high contrast image. It is disclosed in Japanese Patent Laid-Open No. 3-11532.

[0010]

As described above, the cathode ray tube of recent years is required to have multi-functionality, and one of them is antireflection performance and high contrast, and further,
There is a demand for a cathode ray tube that possesses all of the antistatic performance.

It is difficult to provide a cathode ray tube satisfying all of these requirements, especially a cathode ray tube having both antireflection and high contrast, by the above-mentioned conventional techniques.

It is an object of the present invention to provide a cathode ray tube having a novel structure which simultaneously satisfies antireflection performance and high contrast and also has antistatic performance, and a manufacturing method thereof.

[0013]

In order to achieve the above object, the cathode ray tube according to the first aspect of the present invention is such that tin oxide, indium oxide, titanium oxide and antimony oxide are formed on the outer surface of the panel. An antistatic film having a light-absorbing property is formed by coating a solution prepared by mixing at least one selected from the above and a mixed solution of an ethyl silicate alcohol solution with at least one of an organic dye and a pigment, and silicon is provided thereon. -Reflection formed by applying a solution in which at least one ultrafine particle selected from silicon oxide and magnesium fluoride is mixed in at least one alcohol solution selected from alkoxides of zinc, zinc and titanium It is characterized in that a film is provided.

According to a second aspect of the present invention, in the method for producing a cathode ray tube, the outer surface of the panel has at least one selected from tin oxide, indium oxide, titanium oxide and antimony oxide, and ethyl. A step of applying a solution in which at least one of an organic dye and a pigment is mixed in a mixed solution of a silicate and an alcohol solution to form an antistatic film having a light absorption property, and a silicon, zinc and titanium A step of forming an antireflection film by applying a solution in which at least one kind of ultrafine particles selected from silicon oxide and magnesium fluoride is mixed in at least one kind of alcohol solution selected from alkoxides. It is characterized by including at least and.

That is, in the cathode ray tube of the present invention, first, on the outer surface of the panel, in a mixed solution of at least one selected from tin oxide, indium oxide, titanium oxide and antimony oxide and an alcohol solution of ethyl silicate. A solution in which an organic dye and / or a pigment is mixed is applied to the above to provide an antistatic film having a light absorbing property.

The mixing ratio of this underlayer is adjusted so that it has conductivity and antistatic performance. Further, since this layer has a high refractive index, a light interference action occurs with the low-refractive-index SiO ₂ upper layer formed on the layer, which contributes to antireflection.

Further, since a coloring agent (light absorbing agent) is added to this layer, reflection of external light on the inner surface of the panel is reduced, so that the total reflectance of the inner and outer surfaces is reduced and the contrast is improved.

Then, on this underlayer, ultrafine particles of SiO ₂ are dissolved in at least one alcohol solution selected from alkoxides such as ethyl silicate, zinc butoxide and titanium tetra-iso-propoxide. The added material is applied and a uniform fine uneven layer of SiO ₂ is formed on the outer surface of the panel.

At this time, Si decomposed from the alkoxide
O ₂ , ZnO, TiO ₂ etc. act as binders and Si
Fix the O ₂ fine particles.

In addition to the above-mentioned light interference, the antireflection performance is caused by continuous mixing of air with the surface irregularities of the SiO ₂ fine particles to cause a continuous change in the refractive index, and the reflectance is further lowered by the light interference effect.

Coloring agents (light absorbing agents) such as organic dyes differ in light resistance (coloring life) depending on their types and structures, but generally, there are those that fade or discolor with respect to ultraviolet rays or sunlight. In order to prevent this, zinc and titanium alkoxides that absorb ultraviolet rays may be added to the above solution.

After the above-mentioned base layer is applied, the upper layer is applied.
Each is applied alone or to the upper layer, and then baked together to decompose the alkoxide of each layer to form each oxide.

[0023]

As described above, in a cathode ray tube having an envelope composed of a panel, a funnel and a neck, an antistatic film having a light absorbing property containing a coloring agent (light absorbing agent) is provided on the outer surface of the panel. And silicon, zinc,
At least 1 selected from each alkoxide of titanium
An antireflection film is formed by applying a solution in which fine particles of SiO ₂ are mixed in an alcohol solution of a kind, and the antireflection performance is obtained by hydrolysis of alkoxide.
O ₂ , ZnO, and TiO ₂ act as a binder to fix uniformly dispersed fine particles of SiO ₂ and form irregularities of fine particles on the outer surface of the panel to absorb light interference by a continuously changing layer of refractive index. And the interference of light between the underlying high refractive index conductive layer and the upper layer low refractive index SiO ₂ fine particle layer.

The details of this principle are described in the above-mentioned JP-A-63-193101 and Japanese Patent Application No. 5-1130.
The description is omitted here because it is described in Japanese Patent Publication No. 54.

Next, the reason why high contrast performance is obtained will be described.

The contrast C is defined by the equation (1).

[0027] The reflectance of the panel glass of the cathode ray tube for air is R ₁ ,
The reflectance of the panel glass with the antistatic and antireflection film to air is R ₂ (R ₂ = R ₁ when there is no film), the transmittance of the panel glass is T ₁ , and the transmittance of the antistatic and antireflection film is T ₂ ( If there is no film = 1), the brightness of the cathode ray tube is B (cd / m ² ) and the brightness of external light is E (cd / m ² ), the contrast C can be expressed by equation (2). I can.

[0028] From equation (2), it can be seen that the smaller R and T are, the larger C is.

As described above, by adding the coloring agent (light absorbing agent) to the underlying high refractive index conductive layer, the transmittance is lowered and the contrast is increased.

The reduction of the reflectance is caused by both the action of the light interference between the underlayer and the upper layer and the action of the light interference absorption due to the continuous change layer of the refractive index due to the unevenness of the SiO ₂ ultrafine particles on the surface.
To be achieved. The antistatic function is achieved by the conductive particles of the underlayer.

[0031]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view for explaining the structure of one embodiment of a cathode ray tube according to the present invention, and FIG. 2 is a main-part cross-sectional view showing an enlarged portion A of FIG.

In FIGS. 1 and 2, 10 is a panel and 20 is a panel.
Is a funnel, 30 is a neck, 40 is an electron gun housed inside the neck 30, 50 is a shadow mask, 60 is a phosphor layer formed on the inner surface of the panel 10, and 70 is a connecting region between the funnel 20 and the neck 30. An external deflection yoke, 80 is a colored conductive film, 90 is an antireflection film, and 100 is a reinforcing band.

It should be noted that the panel 10, the funnel 20 and the neck 30 constitute a peripheral device of a cathode ray tube, and R, G and B represent red, green and blue electron beams, respectively.

As shown in the enlarged view of FIG.
Colored antistatic film 8 having a light absorbing property formed on the outer surface of
The transmittance is lowered by 0. An antireflection effect is provided by the antireflection film 90 formed by stacking on the upper surface of the colored antistatic film 80.

Incidentally, in order to impart light resistance (sun resistance) to the antireflection film 90, ZnO and Ti which are ultraviolet ray absorbing components are used.
By providing O ₂ as a binder constituent material in addition to SiO ₂ , it is possible to prevent deterioration of the light absorption effect due to aging.

As described above, according to the embodiment of the present invention, it is possible to provide a cathode ray tube having antireflection, high contrast and good antistatic effect.

Next, one embodiment of the method of manufacturing a cathode ray tube according to the present invention will be described.

The solution for forming a colored antistatic film having a light absorbing property used for manufacturing the cathode ray tube according to the present invention is, for example,
Create it as follows.

First, an alcohol solution of ethyl silicate in which Si (OR) ₄ (R represents an alkyl group) is dissolved in ethanol is prepared. To this solution is added SnO ₂ ultrafine particles having an average particle size of 5 to 70 nm. The addition amount and particle size are controlled by the required surface resistance value of the film.

In order to impart the performance as a film forming agent or a binder to this ethyl silicate, a small amount of H ₂ O is added to the above alcohol solution and the reaction is carried out in the presence of a catalyst to obtain its properties.

The alcohol is mainly ethanol or isopropyl alcohol. An acid such as nitric acid or hydrochloric acid may be added as the above-mentioned catalyst, or both may be added without adding it.

By controlling the PH value of the solution, the reaction is gradually promoted and the silica sol is stabilized.

Next, an organic dye or a pigment for coloring is added to these mixed alcohol solutions.

As the organic dye used in this embodiment, many organic dyes can be used. That is, azo dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, carbonium ion dyes, and other dyes can be used. In addition, the pigment used in this example, as an inorganic type, oxide, hydroxide, carbon black, chromic acid,
Azo pigments, phthalocyanines, condensed polycyclic pigments, and other pigments can be used as organic materials such as carbonates, silicates, phosphates, ferrocyanides, and metal powders.

The kind and addition amount of these colorants (light absorbers) are determined according to the intended color tone and light absorption performance.

The thus-prepared solution for forming a colored antistatic film having a light absorbing property is applied to the outer surface of the panel glass at room temperature or at a temperature of 60 ° C. or lower. This application can be carried out by spraying, dipping, spin-coating or any convenient method which can be used for uniform coating.

[0048] In addition, binding to glass (glass panel) of the film, SiO ₂ as a binder is considered to have firmly deposited by bond of SiO-Si and Si-OH. After applying this solution to the surface of the panel glass, in order to cure the coating film, the coated surface is 100 °
It is desirable to heat at C to 200 ° C.

This heating may be carried out in any step before or after applying the next upper layer.

FIG. 3 is an explanatory view showing various specific examples of the constitution of the antistatic film according to the present invention and the characteristics of the cathode ray tube to which the antireflection film is applied.

In the figure, Example 1 is an example of a cathode ray tube other than the present invention, which is shown for comparison, and is an example in the case where the surface treatment of the panel is not carried out. Since it has no light absorption and antireflection performance, The contrast is as low as 2.3, which is poor.

Example 2 is also an example of a cathode ray tube other than the present invention, which is also shown for comparison, in the case where it has an outer surface antireflection property but no light absorption property, and the contrast is 4.8 and still incomplete. Is.

On the other hand, Examples 3 to 7 are examples of the cathode ray tube according to the present invention having both the outer surface antireflection performance and the light absorption performance, and have a large contrast and a good image sharpness. A high-performance cathode ray tube can be obtained. In particular, it can be seen that the contrasts of the concrete examples 6 and 7 are improved about twice as much as the concrete example 2. In addition, Example 7 is an example in which Zn and Ti alkoxides are used for the binder of the upper layer in order to improve the light resistance of the colorant (light absorber).
And the light absorption property of TiO ₂ are improved by the ultraviolet absorption performance.

The surface resistance of these films is 10 ⁸ Ω /
It is below □ and has sufficient antistatic performance.

That is, when the switch of the receiver is turned on, the panel of the cathode ray tube is charged, and the time until it becomes 0 KV is less than 1 second in each case. This static decay time is measured at a position 50 mm away from the center of the face surface of the panel.
Installed, temperature 20-23 ° C, relative humidity 30-35%
The measurement was performed under the following environmental conditions.

In the present embodiment, the description has been given with the light-absorbing performance imparted to the underlying conductive film, but the light-absorbing ability is imparted to the upper antireflection film, or both are imparted with the same ability. It does not matter as a configuration. In addition, the light absorption performance may have wavelength selective absorption, or may have absorption performance over the entire visible light wavelength region.

As described above, according to this embodiment, the transmittance T ₂ can be reduced by absorbing the external light by coloring the antireflection film, so that the contrast is improved.

[0058]

As described above, according to the present invention,
By using a cathode ray tube with an antistatic film and an antireflection film that have a light absorbing property on the outer surface of the panel, a cathode ray tube with an antistatic effect and the reflection of external light can be obtained, which has high contrast and excellent color clarity. It can be provided easily and at low cost.

[Brief description of drawings]

FIG. 1 is a schematic sectional view illustrating the structure of an embodiment of a cathode ray tube according to the present invention.

FIG. 2 is a schematic cross-sectional view of an essential part of FIG. 1 for explaining the structure of one embodiment of the cathode ray tube according to the present invention.

FIG. 3 is an explanatory diagram showing various specific examples of the structure of the charging and antireflection film according to the present invention and the characteristics of the cathode ray tube to which the film is applied.

[Explanation of symbols]

10 panel 20 funnel 30 neck 40 electron gun housed inside the neck 50 shadow mask 60 phosphor layer formed on the inner surface of the panel 70 deflection yoke mounted on the connecting area of the funnel and neck 80 charging having light absorption performance Anti-reflective film 90 Anti-reflective film 100 Reinforcing band.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Kawamura 3300 Hayano, Mobara-shi, Chiba Electronic Device Division, Hitachi, Ltd. (72) Inventor Yoshishige Endo 502 Kintate-cho, Tsuchiura-shi, Ibaraki Hiritsu Manufacturing Machinery Co., Ltd. In the laboratory

Claims (2)

[Claims] 1. A cathode ray tube having an envelope composed of a panel, a funnel and a neck, wherein at least one selected from tin oxide, indium oxide, titanium oxide and antimony oxide is provided on the outer surface of the panel. An antistatic film having a light absorbing property is formed by applying a solution in which at least one of an organic dye and a pigment is mixed in a mixed solution of a type and an alcohol solution of ethyl silicate, and an antistatic film of silicon, zinc, or titanium is provided thereon. An antireflection film formed by applying a solution in which at least one kind of ultrafine particles selected from silicon oxide and magnesium fluoride is mixed in at least one kind of alcohol solution selected from each alkoxide Is a cathode ray tube. 2. A method of manufacturing a cathode ray tube having an envelope including a panel, a funnel and a neck, wherein the outer surface of the panel is selected from tin oxide, indium oxide, titanium oxide and antimony oxide. And a step of applying a solution in which at least one of an organic dye and a pigment is mixed in a mixed solution of at least one kind and an alcohol solution of ethyl silicate to form an antistatic film having a light absorbing property, and At least one selected from silicon oxide and magnesium fluoride in at least one alcohol solution selected from each alkoxide of silicon, zinc and titanium
A method of manufacturing a cathode ray tube comprising at least a step of applying a solution containing a mixture of ultrafine particles to form an antireflection film.