KR100300324B1 - Shadow mask for cathode ray tube and method of manufacturing the same - Google Patents

Abstract

A method of manufacturing a shadow mask that can effectively prevent hole clogging of a shadow mask when coating an electron reflection material or a reinforcing material on the surface thereof to prevent the shadowing of the shadow mask, which is a shadow mask and a screen mesh in a screen printing machine. A first printing step of fixing the paste to the first position and printing the paste, a second printing process of printing the paste after the shadow mask is horizontally moved from the first position to the second position, and the first printing process And a repeating printing step of sequentially repeating the second printing step at least once or more, and a molding step of press molding the flat shadow mask. Here, the movement distance of the shadow mask is approximately half of the pitch of the horizontal hole, so that the screen mesh faces the beam passing hole in the odd-numbered printing so that a portion of the paste remains between the beam passing holes in the even-numbered printing. It is located in no study. Therefore, the paste remaining in the previous printing process is printed in the unperforated area together with the newly applied paste in the next printing process to prevent the accumulation of the paste and to effectively block the blockage of the beam passing hole.

Description

Shadow mask for cathode ray tube and method of manufacturing the same}

The present invention relates to a method for manufacturing a shadow mask for a cathode ray tube, and more particularly, to block the beam passing hole of a shadow mask when coating an electron reflection material or a reinforcing material on the surface of the shadow mask to prevent doming of the shadow mask. It relates to a method of manufacturing a shadow mask that can effectively suppress the.

In general, a cathode ray tube includes a panel forming a fluorescent film screen on an inner surface, a neck portion for mounting an electron gun on an inner circumferential surface, and a trumpet-shaped funnel connecting the panel and the neck to form a bulb. The shadow mask is attached to the back of the car.

The shadow mask serves to separate and land three beams of electron beams emitted from the electron gun to the corresponding phosphors in the phosphor screen by forming a plurality of beam passing holes. Therefore, if the beam passing hole is slightly shifted from the reference position, the path of the electron beam is shifted and the color purity is lowered, for example, to emit other color phosphors. Therefore, it is important to actively suppress the positional change of the beam passing hole.

However, only about 20% of the electron beam emitted from the electron gun passes through the beam passing hole to reach the fluorescent screen, so that the remaining electron beams collide with the shadow mask to raise the temperature of the shadow mask, which causes the shadow mask to convex toward the fluorescent screen. Causes a bloating phenomenon.

In addition, since the shadow mask is made of an extremely thin metal material, a specific portion may be permanently deformed by external shock or vibration.

As a result, the path of the electron beam is shifted, and the color purity is lowered, for example, to emit other color phosphors. Therefore, in order to prevent such a drop in color purity, a method of coating an electron reflection material using a fine grid-shaped screen mesh has been devised. This is a method of disposing the screen mesh on one surface of the shadow mask, and then repeatedly printing the electronic reflective material in a paste state by screen printing to coat the surface of the shadow mask except for the beam passing hole.

However, in the above method, paste remains in a portion of the screen mesh facing the beam passing hole after screen printing, and the paste continues to accumulate in the upper portion during the screen printing process. This has the disadvantage of degrading the electron beam landing characteristics of the shadow mask, such as clogging of the beam passing hole or reduction in diameter.

In order to minimize the blockage of the beam through hole, Korean Patent Application No. 95-40615 proposes a method of forming and coating a photoresist film having the same shape as the beam through hole in the screen mesh.

However, the above method has a disadvantage in that the plate making process for forming a photoresist film is complicated and thus disadvantageous.

Therefore, the present invention is designed to solve the above problems, an object of the present invention is to prevent the accumulation of paste on the screen mesh to block the hole of the shadow mask when coating the electron reflection material or reinforcing material on the surface of the shadow mask To provide a method of manufacturing a shadow mask that can suppress and improve the coating properties.

1 is a perspective view of a shadow mask in a state before the manufacturing process according to the present invention.

2 is a partially enlarged view of a shadow mask and screen mesh mounted to a screen printing machine in a first printing process.

3 to 5 are cross-sectional views taken along a line A-A of the second printing step.

6 is a partially enlarged view of a shadow mask and a screen mesh mounted to a screen printing machine in a second printing process.

7-9 is sectional drawing of the FIG. 6B-B line | wire which shows a 2nd printing process.

10 is a partially enlarged view of a shadow mask having a slot type beam passing hole;

11 is a partially enlarged view of a shadow mask having a circular type beam passing hole.

12 is a perspective view of a shadow mask completed by a molding process.

In order to achieve the above object, the present invention,

The first printing process of fixing both the flat shadow mask and the fine grid screen mesh having the beam passing hole formed in the screen printing machine to the first position, and then applying and printing the paste, and applying the screen mesh to the shadow mask Separating, moving the shadow mask or screen mesh horizontally from the first home position to the second home position, and then applying at least a second printing process, and printing the paste, and at least the first printing process and the second printing process. Provided are a method of manufacturing a shadow mask including a repeating printing step of repeating one or more times and a molding step of press molding a flat shadow mask.

Here, the distance between the first home position and the second home position is preferably about half of the horizontal hole pitch.

As a result, the screen mesh is positioned in the no space between the beam passing holes in the even numbered printing, while the portion of the screen facing the beam passing hole in the odd printing is left. Therefore, the paste left during the odd-numbered printing is printed in the unperforated together with the newly applied paste during the even-numbered printing, thereby preventing the accumulation of the paste and effectively suppressing the blockage of the hole for hole passing.

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

1 shows a shadow mask in a state before the manufacturing process according to the present invention. As shown in the drawing, the shadow mask 10 includes an effective screen portion 4 in which a plurality of beam passing holes 2 are densely formed, and the formation of the beam passing holes 2 is performed by applying photolithography technology. It is made by the corrosion method. The shadow mask 10 body is made of ordinary aluminum kilted steel (AK steel).

Here, the shadow mask 10 includes at least a coating film for suppressing doming of the shadow mask 10, such as reflecting an electron beam and inducing thermal reflection, in order to compensate for the shortcomings of aluminum-kilted steel having a relatively high coefficient of thermal expansion. It is formed on one surface.

Such coating films are typical of metal films such as W, WC, Bi, which have high electron beam reflection efficiency and high thermal radiation efficiency.

Thus, the present embodiment is to provide a method for uniformly coating such a variety of coating materials on one surface of the shadow mask 10 without clogging the beam passing hole (2), according to the present embodiment The manufacturing method of the shadow mask is as follows.

First, both the shadow mask 10 and the screen mesh 20 are fixed in the first in situ position of a known screen printing press. FIG. 2 is an enlarged view of a portion of the shadow mask 10 and the screen mesh 20 fixed to the screen printing machine (not shown). FIG. 3 is a cross-sectional view of the line A-A of FIG. 2.

As shown in the figure, the shadow mask 10 vertically and continuously forms a slot-type beam passing hole 2 applied to a normal cathode ray tube, and is disposed on an upper surface of the shadow mask 10. The screen mesh 20 has a structure in which extremely thin steel wires made of stainless steel, polyester or nylon are organized in a fine lattice shape.

At this time, it is assumed that one point on the common position passing through the screen mesh 20 and the shadow mask 10 fixed at the first position is P1 and P1 ', respectively.

As described above, in the state where the screen mesh 20 and the shadow mask 10 are fixed in the first position, as shown in FIG. 4, the paste 22 constituting the electron reflection material or the reinforcing material is squeezed 24. The first printing process of printing on the screen mesh 20 is performed.

After the first printing process, as shown in FIG. 5, the screen mesh 20 is separated from the shadow mask 10 to be applied to a portion facing the beam passing hole 2 of the shadow mask 10 in the first printing process. The paste 22 remains in the screen mesh 20, but the paste 22 applied to the portion facing the unperforated portion 6 between the beam passing holes 2 is unperforated through the screen mesh 20. It is deposited on the surface of) to form a coating film primarily.

Next, as shown in FIG. 6, the shadow mask 10 or the screen mesh 20 is horizontally moved from the first home position to the second home position to change the relative position between the two members.

This relative position change includes both the case where the shadow mask 10 is moved while the screen mesh 20 is fixed, or the screen mesh 20 is moved while the shadow mask 10 is fixed. Since it is difficult to move the screen mesh 20 during the printing process, it is preferable to change the position of the shadow mask 10. Thus, the shadow mask 10 is horizontally moved to the second correct position and then fixed.

FIG. 7 is a cross-sectional view taken along line BB of FIG. 6, in the first printing process, the point P1 'on the shadow mask 10, which is the same position as the point P1 of the screen mesh 20, is moved horizontally by the moving distance of the shadow mask 10. FIG. Able to know.

At this time, assuming that one point on the shadow mask 10 that is the same position as the point P1 of the screen mesh 20 is the point P2, the moving distance of the shadow mask 10, that is, the distance between the point P1 'and the point P2 is approximately beam. It is preferable that about half of the horizontal pitch (Ph: distance between the beam center holes adjacent to each other in the horizontal direction) of the through hole (2) is used. It means the same value as the distance to.

As a result, the non-perforated portion 6 of the shadow mask 10 faces a portion of the screen mesh 20 that faced the beam passing hole 2 in the first printing process, so that the paste 22 remaining during the first printing process The surface of the shadow mask 10 having the primary coating film is formed to face the no-hole (6).

Next, as shown in FIG. 8, the second printing process is performed by printing the paste 22 using the squeeze 24 on one surface of the screen mesh 20. In the second printing process, as the portion of the screen mesh 20 in which the paste 22 remains during the first printing process faces the non-perspective 6 of the shadow mask 10, the remaining paste 22 is newly applied. The paste 22 is seated on the surface of the non-porous portion 6 to form an additional coating film.

Therefore, after the second printing process, as shown in FIG. 9, when the screen mesh 20 is separated from the shadow mask 10, the screen mesh 20 is subjected to the second printing process without remaining of the paste 22 applied in the first printing process. Only the paste 22 applied at will remain.

Subsequently, after the shadow mask 10 is repositioned from the second home position to the first home position, a third printing process is performed, and then the shadow mask 10 is repositioned from the first home position to the second home position. To perform a fourth printing process.

As such, the present embodiment performs odd-numbered printing while the shadow mask 10 is fixed at the first correct position, and even-numbered printing is performed while the shadow mask 10 is fixed at the second correct position. Is done.

At this time, the movement distance of the shadow mask 10, that is, the distance H between the first and second correct positions is preferably set within a range according to Equation 1 below.

≤ H ≤

Here, D1 denotes a horizontal width of the slot type beam passing hole 2 as shown in FIG. 10, and L1 denotes a width of the horizontal non-perforated portion 6 between the slot type beam passing hole 2. And H and D1 and L1 are all expressed in the same unit.

In addition, the shadow mask may form a circular type beam passing hole 8 applied to an industrial monitor as shown in FIG. 11 as another embodiment. In this case, it is also preferable that the moving distance of the shadow mask 10, that is, the distance H between the first and second correct positions is set within a range according to Equation 2 below.

≤ H ≤

Here, D2 denotes the diameter of the circular type beam passing hole 8, L2 denotes the width of the horizontal non-perforated portion 6 between the circular type beam passing hole 2, and H, D2 and L2 are both It is expressed in the same units.

The range of Equation 1 and Equation 2 is a range that can minimize the amount of the paste 22 remaining in the screen mesh 20, the shadow mask (within the range of Equation 1 and Equation 2 above) In moving 10), the residual paste 22 can be substantially removed.

This paste printing process may be repeated several times until a desired coating film thickness is obtained, and coating films may be formed on both surfaces of the shadow mask 10 as necessary.

Next, the shadow mask 10 having the coating film formed thereon is put into a conventional press molding machine, and as shown in FIG. 12, the effective screen portion 4 having a predetermined curvature, the skirt portion 12, and the like are press processed. Finish to the final shape.

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 present invention prevents the accumulation of the paste on the screen mesh to effectively suppress the blockage of the beam passing hole and form a coating film having a more uniform surface. As a result, the electron beam landing characteristic of the shadow mask can be improved, and the picture quality can be effectively prevented due to the suppressing of the doming.

Claims (3)

A first printing process of fixing a flat shadow mask having a beam through hole formed on the screen printing machine and a fine grid screen mesh to one surface of the shadow mask in a first position, and then applying and printing a paste; A second printing process of spaced apart the screen mesh from the shadow mask, horizontally moving the shadow mask or screen mesh from the first home position to the second home position, and then applying and printing a paste; A repeating printing process of repeatedly performing the first printing process and the second printing process at least once in sequence; And a molding step of press molding the flat shadow mask. The method of claim 1, wherein the distance between the first and second positions is set within a range according to the following equation. ≤ H ≤ here, H is the distance between the first exact position and the second exact position (mm), D1 is the horizontal width of the slot-type beam through hole (mm), L1 is the horizontal blank width (mm) between slot-type beam-through holes. The method of claim 1, wherein the distance between the first and second positions is set within a range according to the following equation. ≤ H ≤ here, H is the distance between the first exact position and the second exact position (mm), D2 is the diameter of the circular beam through hole (mm), L2 is the horizontal non-perforated width (mm) between the circular beam through holes.