KR20030088668A - Mask assembly for cathode ray tube - Google Patents

Abstract

PURPOSE: A mask assembly is provided to achieve improved welding strength between the strength member and reinforcement member. CONSTITUTION: A mask assembly comprises a tension mask(12) having a plurality of electron beam passing holes(14), and which sorts colors of electron beams emitted from an electron gun; a mask frame(16) including a pair of support members(18) disposed to oppose to the longer side of the tension mask and which support the tension mask, and a pair of strength members(20) spaced apart from the support members; and a reinforcement member(26) welded to the bottom or top of the strength member, and which permits the strength member to be transformed in the direction of preventing a plastic deformation of the tension mask during a high temperature heat treatment. The reinforcement member has embossed portions formed at the surface contacting the reinforcement member so as to increase a welding strength. A gap is formed between the reinforcement member and strength member.

Description

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

The present invention relates to a cathode ray tube, and more particularly, to a cathode ray tube mask assembly having enhanced weld strength of a rigid member and a reinforcing material.

In general, a cathode ray tube is a display device that realizes an image by exciting three phosphor beams emitted from an electron gun with R, G, and B phosphors in a phosphor film screen. And a mask assembly including 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 shadow mask mounted on 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 spring assembly for securing 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-mentioned disadvantages and to cope with the trend of larger and flat screens, a tension mask has recently been developed which is fixed to the frame under a tensile force.

The mask assembly having the above-mentioned tension mask typically includes a tension mask provided with a plurality of electron beam through holes, a mask frame for supporting the tension mask in a state in which the tension mask is tensioned in one or two axes, and the support member and the rigid member; It is provided on the outside of each side portion of the member and the rigid member includes a spring for installing the mask frame on the inner surface of the panel (not shown).

The integrally welded tensile mask and mask frame are subjected to a heat treatment process including blackening, and the blackening is performed by introducing a mixed gas of air and propane into the blackening furnace to prevent rust generation and diffuse reflection of the electron beam. As a process of producing a blackening film on the surface of, the maximum temperature of a blackening furnace is the high temperature of about 610-620 degreeC.

By the way, when the deformation amount of the mask frame is large in the heat treatment step, the tensile mask tends to move to the plastic region due to the thermal deformation of the tensile mask and the mask frame, so that the tensile mask does not return to the initial shape after the heat treatment and wrinkles are generated. As it passes through the heat treatment process, changes in the shape and tensile force of the tension mask occur, causing deterioration of quality and image quality.

Therefore, in the high temperature region, the reinforcement of the material having a larger thermal expansion coefficient than the rigid member is welded to one surface of the rigid member, thereby suppressing problems in the heat treatment process, that is, the occurrence of wrinkles due to the plastic deformation of the tensile mask and the decrease in tension in the heat treatment process. .

In the mask assembly of this configuration, the reinforcement is typically welded at two or three welding points by resistance welding.

Here, the resistance welding melts the object to be welded by using a heat generating resistance that is generated from the contact resistance of the object by flowing a high current of 6,000 to 7000 A through the electrode for a short time in a state in which the welded object to be welded is overlapped with a predetermined pressure. Says how to join.

However, in the conventional mask assembly configured as described above, since the reinforcing material is in contact with the rigid member at almost the entire surface, the contact area between the objects to be welded is very large. Therefore, there is a problem that the welding current during resistance welding is dispersed and the welding strength is not satisfactory.

Accordingly, an object of the present invention is to provide a mask assembly for a cathode ray tube which improves the welding strength of the reinforcing member and the rigid member by designing the reinforcing member, focusing on the larger welding area as the contact area between the welded objects becomes smaller.

1 is a bottom perspective view of a mask assembly according to the present invention.

2 is a perspective view of the reinforcement of FIG.

3 is a partial cross-sectional view taken along line “A-A” of FIG. 1.

4 is a cross-sectional view showing another embodiment in which the reinforcement of FIG. 2 is welded to the rigid member.

The object of the present invention as described above,

A tensile mask having a plurality of electron beam passing holes to color-select the electron beam emitted from the electron gun;

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

A reinforcing member which is welded to the lower side or the upper side of the rigid member and deforms the rigid member in a direction of preventing plastic deformation of the tensile mask during a high temperature heat treatment process including blackening;

The reinforcement is provided by a mask assembly for a cathode ray tube having an embossing for improving weld strength on a contact surface with the rigid member, and a gap due to the embossings is formed between the reinforcement and the rigid member.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of a combination of a mask assembly according to the present invention, as shown, the mask assembly installed in the panel not shown at a predetermined distance from the fluorescent film screen (not shown) acts as a color selection electrode A tension mask, a mask frame for supporting the tension mask, and four springs for fixing the mask frame to the panel.

The tensile mask 12 is formed of a plurality of beam through holes 14 by a known photolithography process in an ultra-thin thickness of aluminum-kilted (AK) steel or INVAR steel, the vertical direction of the screen (Fixed in the Y-axis direction in the drawing) is fixed to the mask frame 16.

As described above, the mask frame 16 to which the tensile mask 12 is fixed includes a pair of support members 18 arranged in the X-axis direction in the drawing so as to face the long side portion of the mask 12 to which the tension mask 12 is applied, and these supports. It consists of a pair of U-shaped rigid members 20 which hold | maintain the member 18 at regular intervals.

In addition, a spring 22 for installing the mask frame 16 provided with the tension mask 12 on the inner surface of the panel is installed outside each side portion of the support member 18 and the rigid member 20. In the 20, the rigid member 20 is deformed in a direction to prevent plastic deformation of the tensile mask 12 during the heat treatment at a high temperature (approximately 600 ° C. or higher) including blackening, that is, the direction shown by the arrow 24. The reinforcing material 26 to be welded is fixed.

In FIG. 1, reference numeral 28 denotes a welding point at which the reinforcing material 26 is welded to the rigid member 20.

At this time, the reinforcing material 26 has three embossing 30 on the surface to be welded to the rigid member 20, as shown in FIG.

3, when the reinforcement 26 is welded to the rigid member 20, as shown in FIG. 3, the reinforcement 26 and the rigid member 20 are in contact only with the embossing 30, except for the embossing 30. In the fine gap (G) is formed between the reinforcing material 26 and the rigid member (20).

Therefore, the welding current flowing through the electrode (not shown) is concentrated only on the embossing 30, so that the welding strength between the reinforcing material 26 and the rigid member 20 is improved.

At this time, it is apparent that the reinforcing member 26 is made of a material having a larger coefficient of thermal expansion than the rigid member 20 in the high temperature region.

As shown in FIG. 4, the reinforcement 26 may be fixed to the upper side of the rigid member 20, that is, the surface facing the tension mask 12, in which case the reinforcement 26 is rigid in a high temperature region. Compared with the member 20, the coefficient of thermal expansion is made of a material.

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.

As described above, the mask assembly according to the present invention improves the welding strength by reducing the contact area between the objects to be welded, so that the welding strength can be effectively secured even at a low current and a pressing force.

Claims (3)

A tensile mask having a plurality of electron beam passing holes to color-select the electron beam emitted from the electron gun; A mask frame disposed to face the long side portion of the tensile mask and including a pair of support members for supporting the mask in a state where a tensile force is applied, and a pair of rigid members for keeping the support members spaced apart by a predetermined distance; and; A reinforcing member which is welded to the lower side or the upper side of the rigid member and deforms the rigid member in a direction of preventing plastic deformation of the tensile mask during a high temperature heat treatment process including blackening; The reinforcement includes a mask assembly for a cathode ray tube having an embossing for improving the welding strength on the contact surface with the rigid member, the gap between the reinforcement and the rigid member due to the embossing is formed. The mask assembly of claim 1, wherein the reinforcement is welded to a side opposite to the side facing the tensile mask. The mask assembly of claim 1, wherein the reinforcement is welded to a side facing the tension mask.