KR20030003610A - Mask assembly for cathode ray tube - Google Patents

Abstract

PURPOSE: A mask assembly for a cathode ray tube is provided to prevent the increase of tensile force of a tensile mask due to the thermal expansion of a rigid member by fixing a long-side of the tensile mask on a reinforcing member. CONSTITUTION: A tensile mask(12) is provided with a plurality of beam through-holes. A mask frame(14) includes a pair of support members(22), which are arranged across a long-side of the tensile mask(12) to support the tensile mask(12), and a pair of rigid members(24) for maintaining a predetermined space to the pair of support members(22). A reinforcing member is welded-fixed to the pair of support members(22) to fix the long-side of the tensile mask(12) and prevent the plastic deformation of the tensile mask(12) by thermally expanding the tensile mask(12) to an opposite direction of the applied tensile force.

Description

Mask assembly for cathode ray tube {MASK ASSEMBLY FOR CATHODE RAY TUBE}

The present invention relates to a mask assembly for a cathode ray tube having a tensile mask, and more particularly to a mask assembly that can effectively prevent wrinkles caused by plastic deformation and tension reduction of the mask generated in the high temperature heat treatment process.

In general, a cathode ray tube is a display device in which an image of a three-beam electron beam emitted from an electron gun collides with R, G, and B phosphors in a phosphor film screen to excite the phosphor.

To this end, the cathode ray tube includes a panel having a fluorescent screen on its inner surface, an electron gun that emits an electron beam toward the fluorescent screen, a neck portion on which the electron gun is mounted, a funnel connecting the panel and the neck portion; And a mask assembly having a shadow mask mounted to an inner surface of the panel.

The mask assembly is disposed in close proximity to the screen of the fluorescent film and performs a screening function by separating and landing the electron beam emitted from the electron gun with the corresponding phosphor. A mask mask serving as a color screening electrode, a mask frame for supporting the shadow mask, And a plurality of spring members for fixing the mask frame to the panel.

The shadow mask is formed by forming a plurality of beam through holes in a very thin thickness aluminum AK steel or INVAR steel by a known photolithography process, and then drawing to complete the final shape. These shadow masks are extremely thin compared to a large area, and because of the formation of hundreds of thousands of beam passing holes, their strength is extremely low, so that they are turned off by external impact or thermally expanded toward the fluorescent screen by continuous scanning of the electron beam. (doming) causes a phenomenon.

As such, when the shadow mask is deformed or a dominant phenomenon occurs, the position of the beam passing hole is changed to prevent accurate color separation of the electron beam, thereby lowering the color purity of the screen.

Therefore, in order to overcome the above disadvantages and to cope with the trend of larger and flat screens, a tension mask that is fixed to the frame in the state where a tensile force is applied has been developed.

1 shows an exploded perspective view of a mask assembly according to the prior art, wherein a tension mask 104 provided with a plurality of beam through holes 102 is mainly supported in a vertical direction (in the Y-axis direction in the drawing). Welded to the vertical end of 106, the support member 106 is integrally connected by a pair of rigid members 108.

Here, the support member 106 and the rigid member 108 constitute a mask frame 110 for supporting the tension mask 104.

The integrally welded tensile mask 104 and the mask frame 110 are subjected to a heat treatment process such as a blackening process, a sealing process between the panel and the funnel, and an exhausting process. The blackening process of the heat treatment process includes rust generation and an electron beam. In order to prevent diffuse reflection of air, a mixed gas of air and propane is introduced into the blackening furnace to generate a blackening film on the surface of the tensile mask 104. The maximum temperature of the blackening furnace is a high temperature of approximately 610 to 620 캜.

However, since the mask frame 110 is generally made of a material having a large coefficient of thermal expansion compared to the coefficient of thermal expansion of the tensile mask 104, the mask frame 110, in particular the rigid member 108 in the heat treatment process is a tensile mask The thermal expansion is significantly greater than that of 104, resulting in an increase in the tensile force of the tensile mask 104.

Therefore, during the heat treatment process, the tensile mask 104 causes plastic deformation beyond the elastic region, and after the heat treatment, the tensile mask 104 does not return to the initial shape and wrinkles are generated. A change in shape and tensile force of 104 causes degradation of quality and image quality.

Accordingly, the present invention is to solve the above problems, the shrinkage force to prevent the plastic deformation of the tensile mask in the high temperature heat treatment process is applied directly to the tensile mask to prevent the occurrence of wrinkles caused by the plastic deformation and tension reduction of the mask It is an object to provide a mask assembly for a cathode ray tube that can be effectively prevented.

1 is an exploded perspective view of a mask assembly according to the prior art.

2 is an exploded perspective view of a mask assembly according to the present invention.

3 is a side view of the Y axis in Figure 2 for showing the operation of the present invention.

4 shows another embodiment of a reinforcement used in the mask assembly of the present invention.

FIG. 5 is a side view of the mask assembly for illustrating an installation state of the reinforcement of FIG. 4. FIG.

The object of the present invention as described above,

A tension mask having a plurality of beam passing holes;

A mask including a pair of support members disposed to face the long side of the tensile mask to support the tensile mask in a state where a tensile force is applied, and a pair of rigid members to keep the support members spaced apart by a predetermined distance; A frame;

It is welded and fixed to the support members to fix the long side of the tensile mask, and thermal expansion to shrink the tensile mask in a direction opposite to the direction of applying the tensile force during high temperature heat treatment including blackening to prevent plastic deformation of the tensile mask. Reinforcing material;

It is achieved by a mask assembly for a cathode ray tube comprising a.

The reinforcing member is composed of a band-shaped plate or a bent plate having a greater thermal expansion coefficient than the rigid member, and the tensile mask is disposed inward of the mask frame rather than a welding line set in the reinforcing member, and welded to the reinforcing member. It is fixed.

According to the present invention having such a configuration, the reinforcing member fixing the tensile mask undergoes thermal expansion in both directions around the welding point with the supporting member during the high temperature heat treatment process including blackening. Since it is welded inside the welding point, the tension mask is consequently constricted in the direction opposite to the direction in which the tensile force is applied by thermal expansion of the stiffener.

Therefore, it is possible to prevent the occurrence of wrinkles due to the plastic deformation of the tensile mask and the tension decrease in the high temperature heat treatment process.

Hereinafter, a mask assembly according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 shows an exploded perspective view of the mask assembly according to the present invention, as shown, the mask assembly installed in a panel not shown at a predetermined distance from the fluorescent film screen (not shown) acts as a color selection electrode A tension mask 12, a mask frame 14 supporting the tension mask 12, and a reinforcement 16 fixed to the mask frame 14 to fix a long side of the tension mask 12.

The tensile mask 12 is formed of a plurality of beam through holes 18 by a known photolithography process in an ultra-thin aluminum aluminum (AK) steel or INVAR steel, mainly on the long side, That is, it is stretched in the vertical direction of the screen (Y-axis in the drawing).

In addition, the mask frame 14 supporting the tensile mask 12 in a tensioned state includes a pair of support members 22 disposed in the X-axis direction in the drawing so as to face the long side of the mask 12 to which the tensile force is applied, It consists of a pair of rigid members 24 for holding these support members 22 at regular intervals, and the support members 22 have a C-shape having a vertical portion 22a and a horizontal portion 22b.

At this time, the mask frame 14 is made of a material having a larger coefficient of thermal expansion than the tensile mask 12, for example, SCM415 (a kind of structural steel) having a coefficient of thermal expansion of 14 × 10 ^-6 / ℃.

In the mask frame having such a configuration, the reinforcing member 16 of the present invention is welded along the welding line (WD: Welding Line) shown by the dashed line at the end of the vertical portion 22a of the supporting member 22. (16) is a material having a large coefficient of thermal expansion compared to the rigid member 24 thermally expanding in the tensile direction (Y-axis direction) of the mask frame 14, in particular the tensile mask 12 in the high temperature region, for example 18.2 × 10 ^It consists of a strip-shaped plate made of STS304H having a coefficient of thermal expansion of ⁻⁶ / ° C., and the long side portion of the tension mask 12 is welded to the reinforcement 16 inside the welding line WD.

Hereinafter, the operation of the present invention with reference to FIG.

The rigid member 24 of the mask frame 14 is integrally welded when the tensile mask 12 and the mask frame 14 are subjected to a heat treatment process such as a known blackening process, a sealing process between the panel and the funnel, and an exhaust process. ) Is thermally expanded in a direction away from the center line (CL) to the left and right sides, that is, in the tensile direction of the tension mask 12, the reinforcing material 16 is left and right from the line (WD) for each welding line (WD) The thermal expansion of the tension mask 12 in the direction away from both sides, that is, in the direction of tension and the direction opposite to the tension, respectively, the long side portion of the tension mask 12 is fixed inside the welding line (WD) of the reinforcing material 16, the tension mask The thermal expansion force in the opposite direction to the tension (the direction toward the center line) by the reinforcing material 16 and the thermal expansion force in the tension direction (the direction away from the center line to both the left and right sides) by the stiffener 16 are simultaneously produced in the 12. Will be dissolved.

However, since the reinforcing member 16 is made of a material having a larger thermal expansion coefficient than that of the rigid member 24, the amount of thermal expansion in the opposite direction of tension (the direction toward the center line) by the reinforcing member 16 is applied to the rigid member 24. It has a larger value than the amount of thermal expansion in the tensile direction (direction away from the center line to both the left and right sides).

Accordingly, the tensile mask 12 is opposite to the tension of the tensile mask 12 by the difference between the amount of thermal expansion in the direction opposite to the tension by the reinforcing material 16 and the amount of thermal expansion in the direction toward the tension by the rigid member 24. Since it is reduced in the direction, the tensile mask 12 in the high temperature heat treatment process including blackening can prevent the tensile force from being increased by the thermal expansion of the rigid member 24, which is caused by the increase of the tensile force during the heat treatment process Can be removed.

4 shows another embodiment of the reinforcement used in the mask assembly of the present invention, wherein the reinforcement 16 'of the present embodiment consists of a bent plate.

The reinforcement 16 'of this configuration is welded to the support member 22 at the welding line WD at the end of the vertical portion 22a as shown in FIG. 5, while the welding line WD1 at the side portion of the vertical portion 22b is welded. ) Can be welded to the support member 22 to increase the weld strength of the reinforcement 16 ′ compared to the reinforcement described with reference to FIGS. 2 and 3, thereby fixing the tension mask 12 more firmly. You can do it.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

Thus, the mask assembly according to the present invention is made of a material having a larger coefficient of thermal expansion than the rigid member and by fixing the long side portion of the tensile mask on the reinforcing material fixed to the support member, the tensile mask in the high temperature heat treatment process of the rigid member It is possible to prevent the tensile force from increasing due to thermal expansion.

Therefore, a problem caused by an increase in the tensile force of the tensile mask during the heat treatment process, that is, the tensile mask causes plastic deformation beyond the elastic region, and the thermal deformation process, such as wrinkles in the tensile mask after heat treatment due to the plastic deformation. There is an effect that can remove the problem caused by the change in the shape and tensile force of the tensile mask to pass through the quality and quality deterioration.

Claims (3)

A tension mask having a plurality of beam passing holes; A mask including a pair of support members disposed to face the long side of the tensile mask to support the tensile mask in a state where a tensile force is applied, and a pair of rigid members to keep the support members spaced apart by a predetermined distance; A frame; It is welded and fixed to the support members to fix the long side of the tensile mask, and thermal expansion to shrink the tensile mask in a direction opposite to the direction of applying the tensile force during high temperature heat treatment including blackening to prevent plastic deformation of the tensile mask. Reinforcing material; Mask assembly for a cathode ray tube comprising a. 2. The reinforcing member of claim 1, wherein the reinforcing member is formed of a strip-shaped plate having a larger coefficient of thermal expansion than the rigid member, and the tension mask is disposed inward of the mask frame rather than a welding line set on the strip-shaped plate. Mask assembly for cathode ray tube welded to the reinforcement. The reinforcing member of claim 1, wherein the reinforcing member is formed of an angled bending plate having a larger coefficient of thermal expansion than the rigid member, and the tension mask is disposed inward of the mask frame rather than a welding line set on the bending plate. Mask assembly for cathode ray tube fixed to the welding.