KR100319102B1 - Cathod ray tube having a shadow mask - Google Patents

Abstract

A cathode ray tube having a shadow mask having a reflection reducing material layer formed on a surface thereof is disclosed. Reflection reducing material layer is aluminum, mullite (3Al ₂ O ₃ and 2SiO _2), beta-spawned dyumen (Li ₂ O and Al ₂ O ₃ and 4SiO _2), 3Li ₂ O and _{7B 2 O 3, Li 2 B} 4 It may comprise any one or more materials selected from O ₇ and zeolite. Unintentional light emission, i.e. background light or adjacent light emission, in an area where light emission in the cathode ray tube is not desired is reduced by the reflection reduction function of the shadow mask, thereby improving contrast and color purity in a desired light emission area.

Description

Cathode ray tube having a shadow mask {Cathod ray tube having a shadow mask}

The present invention relates to a cathode ray tube, and more particularly, to an inner surface that can realize improved contrast and color purity by suppressing secondary light emission caused by background light, adjacent light emission, or primary light emission generated inside a cathode ray pipe. A cathode ray tube having a shadow mask having a reflection reducing material layer formed thereon.

The most important factors for lowering the contrast and color purity of the cathode ray tube include background light emission or adjacent light emission caused by electron beam or re-reflection of light generated inside the cathode ray pipe. These background and adjacent light emission results from the reflection of the electron beam or light.

Hereinafter, the background light emission and the adjacent light emission caused in the cathode ray tube will be described with reference to the accompanying drawings, and the problem will be described in detail.

1 and 2 are schematic cross-sectional views of a cathode ray tube illustrated to explain background light emission and adjacent light emission generated in a conventional cathode ray tube, and FIG. 2 is a light emission phenomenon caused by a primary electron beam passing through the shadow mask of FIG. 1. It is a detailed view for explaining.

Referring to FIG. 1, background light emission and adjacent light emission will be described in detail. The primary electron beam starting from the electron gun (not shown) provided in the cathode ray tube 10 is reflected (refer to arrow 35) by about 80% by the inner surface of the shadow mask 20. Only% passes through the gap of the shadow mask 20 to reach the fluorescent film 25 of the CRT 27 (see arrow 50). The fluorescent film 25 is reached to emit light (refer to arrow 55) of the phosphor formed in the desired light emitting region. The light emission by the arrow 55 is referred to as 'primary light emission' as light emission in the target light emission region.

The electron beam reflected by the shielding area of the shadow mask 20 (see arrow 35) is incident on the inner shield 15 provided on the inner wall of the cathode ray tube 10, and then is reflected back to the shadow mask 20 again. A large amount of electron beams reach the fluorescent film on the inner surface of the CRT (see arrow 40) through the gap located in the other area, whereby the phosphor in the area not intended to emit light is emitted (see arrow 45). This phenomenon can be repeated many times by the repetition mechanism of reflection and re-reflection only with one irradiation of the electron beam. Therefore, in the case where the electron beam is continuously irradiated, light emission in the unintentional region as described above occurs uniformly in the entire fluorescent tube 27 fluorescent film instead of a part of the cathode ray tube 27. Such light emission is called "background light emission".

In the case where such background light emission occurs severely, the intensity of light emission in a specific wavelength range is relatively decreased, and thus, contrast and color purity of image quality may be reduced.

Conventionally, the shadow reflectivity of the shadow mask has a range of about 25% to 50% depending on the incident angle or material, and about 25% or more of the inner shield. When comprehensively considering the components constituting the inside of the cathode ray tube made of a material having the above electron reflectance characteristics, about 3% to 8% of the primary electron beam is involved in the background light emission.

On the other hand, some of the approximately 20% of the electron beam that reaches the fluorescent film through the gap of the shadow mask 20 (see arrow 50) is reflected by the phosphor (see arrow 60), and the reflected electron beam is a shadow mask ( After entering the outer surface of 20), it is re-reflected (see arrow 65). Thus, unintentional light emission is caused by light emission (see arrow 70) which is located in a region adjacent to the desired light emission region. This is called adjacent light. Such adjacent light emission is unintentional light emission similar to the background light emission. In the case of adjacent emission, since the typical reflectance of the phosphor is about 28%, it can be seen that about 1 to 2% of the primary electron beam is involved in the adjacent emission. At this time, since the reflection of the electron beam is an inelastic collision, part of the energy of the electron beam is lost in the reflection process. Thus, the energy of the reflected electron beam becomes smaller than the primary electron beam. However, the energy retained by the reflected electron beam may be sufficient to emit the phosphor. Various components constituting the cathode ray tube, such as inner shield, shadow mask, phosphor, etc., vary slightly depending on the type of product, but on average, about 1% to 3% of the primary electron beam emits light in the region adjacent to the emission region. This can lead to a decrease in contrast and color purity.

With reference to Figure 2 will be described in detail with respect to the light emission generated in the undesired adjacent area caused by the reflection of the various forms of the primary emission light emitted from the phosphor in the cathode ray tube. The primary electron beam passes through the gap of the shadow mask (see arrow 30), passes through the aluminum vapor deposition film 22, and causes the primary phosphor to emit light (see arrow 55).

When the light emitted by the primary light emitted by the primary light emitted by the arrow 55 is reflected and light is emitted in a region other than the desired light emitting area through various paths, the secondary light is called 'secondary light emission'. Eggplant is the most common.

First, part of the emitted light passes through the aluminum deposition film 22, enters the outer surface of the shadow mask 20, and then reflects back to emit the phosphor 24 located in the adjacent region (see arrow 80). .

Secondly, the other part of the emitted light passes through the shadow mask (see arrow 75), is reflected by other components inside the cathode ray tube, such as the inner shield ('15' in FIG. 1), and then passes through the cathode ray tube through an arbitrary path. The phosphor 24 formed in any region of (27) is made to emit light (see arrow 85).

Lastly, another part of the emitted light leaks into the adjacent area by interfacial scattering such as phosphor / vacuum / glass panel (see arrow 90), so that light emission occurs in the area adjacent to the desired area.

On the other hand, the above-mentioned various types of secondary light emission are due to about 2% to 20% of the reflected electron beam causing background light emission. Therefore, the secondary light emission is relatively weak compared to the background light or the adjacent light light. However, in order to precisely control phosphor emission in a predetermined region, the secondary emission may also become an important problem.

As described above, the conventional cathode ray tube is made intentionally in an undesired light emitting region by an electron beam or primary reflection light reflection or rereflection mechanism (see arrow 35 in FIG. 1 and arrow 75 in FIG. 2). As a result of the light emission phenomenon, the light emission efficiency in the actual target area is lowered. In addition, the shadow mask of the conventional cathode ray tube has a problem in that an oxide of a large atomic number such as bismuth oxide is formed on the opposite surface of the electron gun for the purpose of electron reflection, thereby increasing the unintentional light emission phenomenon as described above. .

The technical problem to be achieved by the present invention is to reduce the contrast and color purity of the cathode ray tube by suppressing secondary light emission caused by the background light, adjacent light emission and primary light emission caused by the electron beam or light is reflected back in the cathode ray tube To solve the problem.

An object of the present invention is to provide a cathode ray tube having a shadow mask that can achieve such a technical problem.

1 and 2 are schematic cross-sectional views of a cathode ray tube illustrated to explain background light emission and adjacent light emission generated in a conventional cathode ray tube, and FIG. 2 is a light emission phenomenon caused by a primary electron beam passing through the shadow mask of FIG. 1. It is a detailed view for explaining.

Figure 3 is a schematic diagram for explaining that the above-described conventional light emission phenomenon in the cathode ray tube with a shadow mask according to the present invention is reduced.

In order to achieve the above technical problem, the present invention provides an aluminum, Al ₂ O ₃ , mullite (3Al ₂ O ₃ ㆍ 2SiO ₂ ), beta-spondumen (Li ₂ O · Al ₂ O ₃ · 4SiO ₂ ), 3Li and the ₂ O and _{7B 2 O 3, Li 2 B} 4 O 7, characterized by providing a cathode ray tube comprising a shadow mask the reflection reducing material layer including any one or more materials selected from the group consisting of zeolite are formed.

In this case, the reflective reducing material layer may be used as a material of the shadow mask, and of course, may be manufactured in the form of a foil if the purpose is to reduce the reflection of the electron beam or the emitted light incident on the shadow mask surface. There is no limit.

According to the present invention, since unwanted electron beam or light is incident on the surface of the shadow mask inside a cathode ray tube equipped with a conventional shadow mask, it is caused by background light emission generated by reflection, secondary light emission by adjacent light emission, or light emission. Since the contrast and color purity of the cathode ray tube are deteriorated, it is presented for the purpose of solving this problem. To this end, the cathode ray tube includes a shadow mask having a reflection reducing material layer formed on a surface thereof.

Hereinafter, the present invention will be described in more detail with reference to Examples.

The method of forming the reflection reducing material layer on the surface of the shadow mask is various, and may be formed using the following methods of forming the reflection reducing material layer.

Method of forming a reflection reducing material layer 1

The reflection reducing material to be formed on the surface of the shadow mask, and the materials shown in Examples 1 to 4, Examples 7 and 8, respectively, are dispersed in an epoxy resin and a solvent, and then a low melting point frit of glass type is used for the binder. After the addition was sufficiently stirred, and prepared in the form of a paste. The component ratio of the prepared paste is appropriately adjusted to have a viscosity suitable for printing. The ratio of epoxy resin and solvent is preferably 3: 7 to 7: 3, and the low melting frit is preferably 5% to 50% of the reflection reducing material by volume ratio. Thereafter, the prepared paste is formed on the shadow mask surface by printing, which is sufficiently dried and then the epoxy resin is cured. Continuously forming and blackening to form a strong reflection reducing material layer by the low melting frit.

Formation method of reflection reducing material layer 2

The reflective reducing material to be formed on the surface of the shadow mask, and the materials shown in Examples 1 to 4, 7 and 8, respectively, were dispersed in an epoxy resin and a solvent, and then a low melting point frit of a glass-based glass binder was used. After addition and stirring sufficiently, it prepares in paste form. The proportion of the components of the paste is adjusted to be suitable for painting on the shadow mask with a brush. The ratio of epoxy resin and solvent is preferably 1: 9 to 5: 5, and the low melting point frit is preferably 5% to 50% of the reflection reducing material by volume ratio. After forming the prepared paste on the shadow mask surface with a brush or the like, it is dried to cure the epoxy resin.

Method of Forming Reflective Material Layer 3

Coatings in Examples 2 to 7 were carried out as follows. Before the hole was formed, the coating material was applied to the entire surface on the sheet for mask and dried to form the hole. A continuous coating and blackening step may be performed to form a solid coating film by low melting frit.

Formation method of reflection reducing material layer 4

In Examples 5 and 6 below, the raw material of lithium acetate and boron (B) is used as a raw material of lithium (Li), and a soluble material such as boric acid, and the solution dissolved in alcohol is mixed at a desired ratio, and epoxy resin is added thereto. After that, a shadow mask is dipped therein to form a reflection reducing material layer. Subsequent molding and blackening steps harden the reflection reducing material layer.

In Examples 1 to 4, Examples 7, and 8 according to the present invention, the reflection reducing material layer was formed on the surface of the shadow mask according to the method 1 for forming the reflection reducing material layer. Meanwhile, in Examples 5 and 6, a reflection reducing material layer was formed on the surface of the shadow mask according to the method of forming the reflection reducing material layer 4.

Example 1

An aluminum layer having a thickness of about 0.1 micrometer was formed on the surface of the shadow mask. After that, the reflectance of the reflected electron beam after being incident on the shadow mask surface was measured. When the reflectance of the conventional shadow mask is based on 100%, the reflectance in the shadow mask according to Example 1 is lowered to 55%.

Example 2

An Al ₂ O ₃ layer having a thickness of about 0.1 micrometer was formed on the shadow mask surface. In the same manner as in Example 1, the reflectance of the electron beam was measured. The reflectance of the shadow mask according to Example 2 was lowered to 44% as compared to the conventional shadow mask.

Example 3

On the surface of the shadow mask, a mullite (mullite, 3Al ₂ O ₃ ㆍ 2SiO ₂ ) layer having a thickness of about 0.1 micrometers was formed. In the same manner as in Example 1, the reflectance of the electron beam was measured. The reflectance at the shadow mask surface according to Example 3 is lowered to 46% as compared to the conventional shadow mask.

Example 4

A beta-spondumen (Li ₂ O.Al ₂ O ₃ .4SiO ₂ ) layer having a thickness of about 0.1 micrometers was formed on the shadow mask surface. In the same manner as in Example 1, the reflectance of the electron beam was measured. The reflectance of the shadow mask according to Example 4 was lowered to 43% as compared to the conventional shadow mask.

Example 5

A 3Li ₂ O.7B ₂ O ₃ layer having a thickness of about 0.1 micrometer was formed on the shadow mask surface. In the same manner as in Example 1, the reflectance of the electron beam was measured. The reflectance of the shadow mask according to Example 5 was lowered to 27% as compared to the conventional shadow mask.

Example 6

A layer of Li ₂ B ₄ O ₇ having a thickness of about 0.1 micrometer was formed on the shadow mask surface. In the same manner as in Example 1, the reflectance of the electron beam was measured. The reflectance at the shadow mask surface according to Example 6 was lowered to 27% as compared to the conventional shadow mask.

Example 7

The zeolite layer having a thickness of about 0.1 micrometer was coated on the shadow mask surface. In the same manner as in Example 1, the reflectance of the electron beam was measured. The reflectance at the shadow mask surface according to Example 7 was lowered to 40% as compared to the conventional shadow mask.

Example 8

A carbon layer having a thickness of about 0.1 micrometer was coated on the shadow mask surface. In the same manner as in Example 1, the reflectance of the electron beam was measured. The reflectance at the shadow mask surface according to Example 8 was lowered to 70% as compared to the conventional shadow mask.

Comparative example

On the surface facing the electron gun of the conventional shadow mask, an electron reflecting material such as bismuth oxide is formed, which has a problem of further increasing unintentional light emission as described above. A comparative example for comparing with an embodiment according to the present invention is a cathode ray tube equipped with such a conventional shadow mask, in which the reflectance of the electron beam incident on the shadow mask surface is set to 100% as a relative reference value.

Hereinafter, the operation of remarkably reducing the secondary light emission phenomenon caused by the background light, the adjacent light or the light emitted by the conventional problem in the cathode ray tube having the shadow mask manufactured in the above embodiment will be described in more detail with reference to the accompanying drawings. Let's explain.

Figure 3 is a schematic diagram for explaining that the above-described conventional light emission phenomenon in the cathode ray tube with a shadow mask according to the present invention is reduced. Meanwhile, in FIG. 3, the shadow mask 120 according to the present invention is thicker than other members, but this is merely an exaggeration of the fact that the reflection reducing material layer is formed on the surface of the shadow mask 120.

According to FIG. 3, the shadow mask according to the present invention significantly reduces the conventional background light emission by reducing the reflection of incident electron beams or emitted light. The primary electron beam starting from an electron gun (not shown) provided in the cathode ray tube 10 (see arrow 30) is reflected by the inner surface of the shadow mask 120 (see arrow 135). It is significantly reduced in comparison with the above.

On the other hand, only about 20% of the primary electron beam 30 passes through the gap of the shadow mask 120 to reach the fluorescent film 25 of the CRT 27 (see arrow 50). The fluorescent film 25 is reached to emit light (refer to arrow 55) of the phosphor formed in the desired light emitting region. The surface of the shadow mask 120 is the reflection reducing materials such as aluminum, Al ₂ O _3, mullite (3Al ₂ O ₃ and 2SiO _2), beta-spawned dyumen (Li ₂ O and Al ₂ O ₃ and 4SiO ₂ ), 3Li ₂ O and _{7B 2 O 3, Li 2 B} 4 O 7, because it consists of a material comprising the zeolite and at least one selected from carbon, of the shadow mask 120 is significantly reduced compared to the conventional positive Reflect only the beam (see arrows 135, 165).

This significantly reduces the reflection of the electron beam from the shadowmask surface, which is the main cause of conventional background light (see arrows 140 and 145) and adjacent light (arrows 165 and 170) (indicated by the dotted lines in FIG. 3), The above-mentioned conventional problem can be solved.

According to the embodiments according to the present invention, the improvement of the contrast and the color purity in the light emitting region is specifically improved as follows. That is, the light emission in the non-emission area is reduced to about 25 to 50% level according to the reflection reducing material and the thickness of the layer used in the shadow mask, and as a result, the contrast of the light emission area is improved to about 33 to 167%. In addition, when the monochromatic color coordinate (x, y) of the conventional cathode ray tube is red (0.645, 0.316), green (0.275, 0.607), blue (0.143, 0.054), when the shadow mask according to the present invention is used, a reflection reducing material And the emission in the non-luminescing region was reduced to a level of about 25-50% depending on the thickness of the layer. Meanwhile, the red color coordinates of the cathode ray tube using the shadow mask according to the present invention are (0.663, 0.314) to (0.672, 0.316), the green color coordinates are (0.274, 0.613) to (0.274, 0.618), and the blue color coordinates are (0.141, 0.050). ) To (0.140, 0.048), respectively, to increase the color reproduction range by 107 to 110%.

In addition, in order to prevent shadow doming of the shadow mask, when the electron reflecting material such as Bi ₂ O ₃ is coated on the inner side of the shadow mask, that is, the side opposite to the direction of the electron gun, the electron reflection becomes more intense and the purity and color purity It may be further deteriorated. This problem can be more preferably solved if the cathode ray tube is provided with the shadow mask according to the present invention.

The above embodiments are only described in detail to aid the understanding of the present invention, and should not be understood for the purpose of limiting the scope of the present invention. In addition, various modifications to the present invention can be easily made by those skilled in the art, and it is obvious that they belong to the scope of the present invention.

A cathode ray tube having a shadow mask having a reflection reducing material layer formed on a surface thereof according to the present invention controls the mechanism of reflection or re-reflection of an electron beam or light in the cathode ray tube, thereby causing background light emission resulting from a conventional reflection or re-reflection mechanism. And significantly reducing light emission unintentionally generated in unwanted areas such as adjacent light emission, thereby improving contrast and color purity in the light emitting area.

Claims (1)

Aluminum on the surface, mullite (3Al ₂ O ₃ and 2SiO _2), beta-spawned dyumen (Li ₂ O and Al ₂ O ₃ and 4SiO _2), 3Li ₂ O and _{7B 2 O 3, Li 2 B} 4 O 7 , and Cathode ray tube having a shadow mask formed with a layer of reflective material comprising at least one material selected from the group consisting of zeolite.