KR20000054917A - Mask assembly for cathode ray tube - Google Patents

Abstract

PURPOSE: A mask assembly for cathode ray tube is to improve a strength and a workability of a shadow mask and to prevent a doming, thereby prevent a lowering of a quality of image. CONSTITUTION: A mask assembly for cathode ray tube comprises a shadow mask(20) having a punched portion(22) on which a plurality of beam passing holes are formed and a non-punched portion(24) at a circumference of the punched portion, a mask frame which is weld to a peripheral of the shadow mask to support the shadow mask, a plurality of spring members which are interposed between the mask frame and a stud pin buried in a panel and fixes the mask frame to the panel. In the assembly, a horizontal radius of curvature of the punched portion is formed to be larger than that of the non-punched. A vertical radius of curvature of the punched portion is formed to be larger than that of the non-punched portion.

Description

Mask assembly for cathode ray tube

The present invention relates to a mask assembly for a cathode ray tube, and more particularly, a mask for a cathode ray tube, which improves the workability and strength of a shadow mask in a model applied to a large planar cathode ray tube, and suppresses image quality by suppressing doming. It is about assembly.

In general, the mask assembly is disposed to be parallel to the panel forming a fluorescent screen on the inner side to separate and landing three stem electron beams emitted from the electron gun with the corresponding phosphor. For this purpose, the mask assembly includes a plurality of beam passing holes. And a shadow mask for forming and separating and landing the electron beam, a mask frame for supporting the shadow mask, and a plurality of spring members for fixing the mask frame to the panel.

Here, the cathode ray tube is gradually planarized and enlarged in order to prevent image distortion and to enlarge a viewing angle. Accordingly, the shadow mask mounted on the cathode ray tube is also planarized and enlarged in correspondence with the shape of the panel.

In addition, the shadow mask is usually made of aluminum-kilted steel, the aluminum-kilted steel tends to easily induce a doming phenomenon that convexly expands toward the panel when the thermal energy is increased by electron beam scanning because of its low thermal expansion coefficient. .

Therefore, in order to prevent this, a coating film for suppressing electron beam absorption is formed on the surface of the aluminum-kilted steel, or a shadow mask may be fabricated with Invar steel having a lower coefficient of thermal expansion than the aluminum-kilted steel.

However, since the Invar steel is inferior in workability than aluminum-kilted steel, the characteristics of the shadow mask may be deteriorated, and such deterioration tends to increase as the shadow mask is planarized.

FIG. 5 is a perspective view of a shadow mask according to the prior art, and as shown, the shadow mask 1 has no holes around the hole 3 and the hole 3 forming a plurality of beam passing holes 3a. It consists of a mask part 7 which consists of (5), and the skirt part 9 formed by bending from the four edges of the said mask part 7, The said mask part 7 consists of a substantially flat surface corresponding to the panel shape. .

As such, when the mask portion 7 is formed in a flat surface, the boundary between the mask portion 7 and the skirt portion 9 is sharply bent, which is disadvantageous to molding with Invar steel, which lacks workability, and has a higher strength than when formed at a predetermined curvature. The mask portion 7 may cause full or partial deformation during the manufacturing process or during operation of the cathode ray tube.

This deformation of the mask portion 7 acts as a major cause of deterioration of the image quality by changing the position of the beam passing holes 3a to prevent accurate landing of the electron beam.

Therefore, the present invention was devised to solve the above problems, and an object of the present invention is to improve the workability and strength of a shadow mask in a large planar shadow mask made of Invar steel, and to suppress the doming so as to prevent deterioration of image quality. The present invention provides a mask assembly for a cathode ray tube.

1 is a cross-sectional view of a cathode ray tube including a mask assembly according to the present invention.

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

3 is a cross-sectional view taken along the line A-A of FIG. 2.

4 is a cross-sectional view taken along the line B-B of FIG. 2.

5 is a perspective view of a shadow mask according to the prior art.

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

A shadow mask including a hole having a plurality of beam passing holes and a hole free around the hole, a mask frame welded to the circumference of the shadow mask to support the shadow mask, and embedded in the mask frame and the panel. In a mask assembly for a cathode ray tube including a plurality of spring members interposed between stud pins to fix a mask frame to a panel, the horizontal curvature radius and the vertical curvature radius of the shadow mask are represented by Equations 1 and 2 below. It provides a mask assembly for a cathode ray tube made to be set within the range.

R1> R2

R3 ＞ R4

Here, R1 is a horizontal curvature radius of the perforated portion, R2 is a horizontal curvature radius of the non-perforated portion, R3 is a vertical curvature radius of the perforated portion, and R4 represents a vertical curvature radius of the non-perforated portion.

In this way, by setting the radius of curvature of the non-perforations less than the radius of curvature of the shadow masks to form more curvatures, the workability of the shadow mask made of Invar steel is improved, and the strength is compensated by supporting relatively flat pores. As a result, local doming and partial deformation are prevented, and the surface area of the non-perforated area is enlarged to increase heat dissipation per unit time, thereby making it more advantageous to prevent doming.

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

1 is a cross-sectional view of a cathode ray tube including a mask assembly according to the present invention.

As shown in the drawing, the cathode ray tube includes a panel 4 for forming a fluorescent film screen 2 on its inner surface, a neck portion 8 for mounting an electron gun 6 on its inner circumferential surface, and the panel 4 and a neck portion 8. The funnel 10 of the shape of a trumpet which connects) is combined to form a tube 12.

The fluorescent film screen 2 is a film in which a plurality of green, blue, and red phosphors are patterned in a predetermined shape, and the phosphors are excited by scanning the electron beam 14 emitted from the electron gun 6 to produce a predetermined image. Will be implemented.

In this case, the shadow mask 20 disposed on the rear surface of the fluorescent film screen 2 is made to be substantially flat to correspond to the screen portion 4a of the panel 4, and for a plurality of beam passing corresponding to the phosphor pattern. The hole 22a is formed to separate and land the three stem electron beams 14 emitted from the electron gun 6 into the respective phosphors.

As such, the shadow mask 20, which plays an important role in color image realization, is made of Invar steel having a low coefficient of thermal expansion, which is disadvantageous in flat mask molding due to poor workability. In particular, the mask assembly according to the present embodiment effectively complements the workability and strength of a large flat shadow mask made of Invar steel.

2 is an exploded perspective view of the mask assembly according to the present invention, FIG. 3 is a cross-sectional view taken along the line A-A of FIG. 2, and FIG. 4 is a cross-sectional view taken along the line B-B of FIG. 2.

As shown in the drawing, the mask assembly includes a shadow mask 20, which is a color screening means, a mask frame 30 supporting the shadow mask 20, and a plurality of masks fixing the mask frame 30 to the panel 4. It consists of a corner pin spring (40).

In more detail, the shadow mask 20 includes a mask portion 26 that forms a plurality of beam passing holes 22a and a skirt portion 28 that is bent from four edges of the mask portion 26. And the mask part 26 includes a hole part 22 in which a plurality of beam passing holes 22a are formed, and a hole part 24 positioned between the hole part 22 and the skirt part 28. )

The mask frame 30 is bent toward the shadow mask 20 from four edges of the rectangular bottom portion 32 forming the opening 32a for electron beam passing through, and the shadow mask 20 is formed as a shadow mask. And a side portion 34 welded to the skirt portion 28 of the 20.

The shadow mask 20 having such a configuration is fitted into or out of the mask frame 30, and then around the skirt portion 28 of the shadow mask 20 and the side portions 34 of the mask frame 30 that are in contact with each other. It is integrated by performing a series of welding operations along the.

The mask frame 30 integrated with the shadow mask 20 is fixed to the stud pin 16 embedded in the inner surface 4b of the panel 4 by the corner pin spring 40 and mounted on the tube 12. do.

Here, the shadow mask 20 according to the present embodiment is set so that the horizontal and vertical curvature radii of the perforations 22 and the perforations 24 are different from each other so that the perforations 22 and the perforations 24 are respectively different. 3 shows a horizontal curvature radius of the shadow mask 20, and FIG. 4 shows a vertical curvature radius of the shadow mask 20.

The difference between the radius of curvature of the perforations 22 and the radius of curvature of the non-perforation 24 is to improve the processability of the shadow mask 20 and to compensate for the mechanical strength of the perforations 22. The mask assembly is formed by setting the radius of curvature of the perforations 22 and the perforations 24 of the shadow mask 20 within the ranges according to the following equations (1) and (2).

[Equation 1]

R1> R2

[Equation 2]

R3 ＞ R4

Here, R1 (mm) represents the horizontal curvature radius of the perforated portion 22, R2 (mm) represents the horizontal curvature radius of the non-porous portion 24. In addition, R3 (mm) represents the vertical curvature radius of the perforated portion 22, R4 (mm) represents the vertical curvature radius of the non-porous portion 24.

R1, the horizontal curvature radius of the hole 22, represents the distance from the point C1 of the center of curvature of the hole 22 in FIG. 3 to a point on the hole 22, and the horizontal of the non-hole 24 The radius of curvature R2 represents the distance from the point C2 that is the center of curvature of the no-hole 24 to one point on the no-hole 24.

In addition, the radius of curvature R3 in the vertical direction of the hole 22 represents the distance from the point C3 of the center of curvature of the hole 22 to one point on the hole 22 in FIG. 4, and the vertical of the holeless 24 is vertical. The radius of curvature R4 represents the distance from the point C4 that is the center of curvature of the no-hole 24 to one point on the no-hole 24.

As described above, the shadow mask 20 according to the present exemplary embodiment is formed by forming a smaller curvature radius of the non-hole 24 as compared with the hole 22 formed to be substantially flat to further form the non-hole 24. . As a result, molding is easier than when the entire mask portion 26 is flat, thereby improving the processability of the shadow mask 20.

In addition, the curvature-free hole 24 supports the substantially flat hole 22 on both sides, thereby improving the strength of the hole 22, thereby increasing the heat energy or the mask portion 26 by external vibration or impact. Effectively prevents full or partial deformation.

In addition, the shadow mask 20 according to the present exemplary embodiment may increase the surface heat dissipation per unit time by increasing the surface area of the non-porous portion 24 more than the conventional shadow mask as the non-porous portion 24 is formed to be curvature. As a result, the mask portion 26 may be more advantageously prevented from doming by electron beam scanning.

Here, the shadow mask 20 has a ratio between the horizontal and vertical curvature radii R1 and R3 of the perforated part 22 and the horizontal and vertical curvature radii R2 and R4 of the non-perforated part 24 about 2: It is especially preferable that it is three.

For example, in the shadow mask 20 applied to a 32-inch cathode ray tube, the horizontal curvature radius R1 of the perforated part 22 is 1,151 mm, and the horizontal curvature radius R2 of the non-perforated part 24 is 767 mm. Most preferably, the vertical curvature radius R3 of the hole 22 is 1,275 mm, and the vertical curvature radius R4 of the non-hole 24 is 850 mm.

Thus, this embodiment when setting the horizontal and vertical curvature radius (R1, R3) of the perforated portion 22 and the horizontal and vertical curvature radius (R2, R4) of the non-perforated portion 24 in a ratio of approximately 2: 3. It is possible to maximize the effect by the most, which is based on a number of experiments and simulation results on the processability and the dooming characteristics according to the curvature radius of the perforated part 22 and the non-perforated part 24 substantially.

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 processability of the shadow mask more easily, and complements the strength of the perforated part to effectively prevent the entire or partial deformation of the mask part, and increases the surface area of the unperforated part to increase heat per unit time. Increasing the amount of divergence has more advantageous properties in preventing doming.

Claims (1)

A shadow mask including a hole having a plurality of beam passing holes and a hole free around the hole, a mask frame welded to the circumference of the shadow mask to support the shadow mask, and embedded in the mask frame and the panel. In the mask assembly for a cathode ray tube comprising a plurality of spring members interposed between the stud pin to secure the mask frame to the panel, And a horizontal curvature radius and a vertical curvature radius of the shadow mask are set within a range according to Equations 1 and 2 below. [Equation 1] R1> R2 [Equation 2] R3 ＞ R4 here, R1 is the horizontal curvature radius of the perforated part (mm), R2 is the radius of curvature of the horizontal plane in mm (mm), R3 is the vertical radius of curvature of the perforations (mm), R4 is the radius of curvature in the vertical direction (mm).