KR20030012214A - Mask Frame Assembly of Colour CRT - Google Patents

Abstract

PURPOSE: A mask frame assembly for a color cathode ray tube is provided to simplify welding procedures and prevent deformation of frame, while improving compression strength. CONSTITUTION: A mask frame assembly comprises a pair of frame bars(20) each of which has a nearly L-shaped cross section and a top surface where a shadow mask is welded; and a pair of frame legs(30) each of which has a nearly square pipe type cross section and both ends coupled to frame bars. The frame bar has a bottom surface(22) where a cut-away portion(26) is formed. The frame leg has both ends with an inclined portion(32) which is inclined downward as it goes from outside toward inside of the end of the frame leg. The frame leg is introduced in the cut-away portion of the frame bar, and the outer surface of the frame leg exposed through the inclined portion is welded to a side surface(24) of the frame bar. The inclined portion of the frame leg has a tilt angle of 30 to 50 degrees.

Description

Mask Frame Assembly of Color Cathode Ray Tubes

The present invention relates to a mask frame of a cathode ray tube, and more particularly, to minimize deformation of the heat affected zone during welding of the frame bar and frame leg, thereby preventing deformation of the frame, simplifying the welding process, and improving compressive strength. A mask frame assembly of a suitable colored cathode ray tube is provided.

In general, as shown in FIG. 1, the color cathode ray tube emits light by passing an electron beam emitted from the electron gun 2 through a shadow mask 4 made of a thin metal plate, and landing on the screen surface 8 formed on the inner surface of the panel 6. This reproduces an image.

The shadow mask 4 has fine color separation holes formed therein to allow electron beams to pass through, so that some of the beams emitted from the electron gun 2 are filtered by these color separation holes and allowed to pass through the screen surface 8. Only a predetermined portion of is reached to cause the panel 6 to emit light.

As such, the shadow mask 4, which allows the electron beam emitted from the electron gun 2 to reach the desired screen surface 8, is spaced a predetermined distance in the direction of the electron gun 2 from the screen surface 8 inside the panel 6. As a means for mounting the shadow mask 4 inside the cathode ray tube, a mask frame 10 to which the shadow mask 4 is bonded is provided, and the mask frame 10 is provided with a bimetallic holder spring. The holder spring 12 is attached to the stud pin 14 fixed to the inner circumference of the skirt portion 6a of the panel 6 so that the shadow mask 4 and the mask frame 10 are attached to the panel ( 6) It is suspended inside.

Figure 2 shows a conventional mask frame assembly for a typical color cathode ray tube in more detail, the conventional mask frame 10 is a pair of frame legs 30, a short side and a pair of frame bars 20 to form a long side. Is made in combination. The frame bar 20 has an approximately "L" shaped cross section while the shadow mask 4 is welded to the upper surface thereof, and the frame leg 30 has an approximately quadrangular pipe-shaped cross section, and both ends thereof have the frame bar ( 20 is welded to the bottom surface, and the above-described holder springs 12 are attached to the frame legs 30, respectively, to correct the doming phenomenon of the shadow mask 4 due to thermal expansion.

Part of the electron beam emitted from the electron gun penetrates through the screen of the shadow mask and lands on the screen surface of the panel. The remaining electron beam impinges on the surface of the shadow mask, causing thermal deformation in the shadow mask, causing the shadow mask to swell. Phenomenon occurs. As a result, the position of the color selection hole of the shadow mask is changed to cause an error in the landing position of the electron beam, thereby degrading image quality or color purity.

In this case, the above-described holder spring 12 corrects the domming of the shadow mask 4. When the shadow mask 4 causes the domming, the mask frame 10 expands due to heat transfer from the shadow mask 4. After the differential correction is performed, the holder spring 12 is deformed by heat transfer from the mask frame 10 to perform secondary correction to correct the shadowing of the shadow mask.

For this reason, the frame bar 20 and the frame leg 30 will be very important. In the conventional mask frame assembly, the four sides of the pipe-shaped frame leg 30 are welded to the bottom of the frame bar 20 all around. Since it has a structure that is bonded to, the heat affected zone (Heat Affacted Zone) by the welding is increased while the welding time is required a lot, the frame is distorted due to the thermal stress. If the frame is distorted, the compression is not uniform after the compression of the shadow mask 4 to remove the compression after welding, causing the deformation of the shadow mask 4 so that accurate correction cannot be made.

In addition, in the related art, in order to discharge the welding gas into the inner space of the frame leg 30 during welding, a gas discharge hole 32 must be formed inside the frame leg 30, and unnecessary work is added. In addition, there is a difficult and uncomfortable problem of his formation work.

The present invention, in consideration of the various problems as described above to minimize the welding heat affected zone during the fabrication of the frame to prevent distortion of the frame due to thermal stress, and simplify the welding process and does not require a separate gas discharge hole in the frame leg It is therefore an object of the present invention to provide a mask frame assembly of color cathode ray tubes suitable for improving the compressive strength of a frame at the same time.

1 is a view showing the structure of a conventional typical color cathode ray tube

2 is a perspective view showing a mask frame structure of a conventional color cathode ray tube;

Figure 3 is an exploded perspective view showing a mask frame structure according to the present invention

Figure 4 is an assembled perspective view of the mask frame structure according to the present invention

5 is a front view of FIG. 4

6 is a side cross-sectional view of FIG. 4

<Explanation of symbols for the main parts of the drawings>

4: shadow mask 10: mask frame

20: frame bar 22: bottom

24: side 26: cutout

30: frame leg 32: inclined portion

In order to achieve the above object, the mask frame assembly of the color cathode ray tube according to the present invention comprises a pair of frame bars having a shadow mask bonded to an upper surface of the side surface while being made of an “L” shaped cross section having a lower side and a side edge. A mask frame assembly of a color cathode ray tube comprising a pair of frame legs whose ends are joined to the frame bar while forming a pipe-shaped cross section.

On both ends of the frame bar, a cutout of a predetermined length is formed in a state coinciding with the side surface, and an end portion of the frame leg forms an inclined portion that slopes downward from the outside to the inside, The frame leg is inserted into the outer surface of the frame leg exposed through the inclined portion and the side of the frame bar is bonded by spot welding.

Preferably, the inclination angle θ of the inclined portion of the frame leg is maintained at an angle of 30 degrees to 50 degrees.

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

As shown in FIGS. 3 and 4, the mask frame has a pair of frame bars 20 having a cross-section having an approximately "L" shape and a shadow mask 4 is welded to an upper surface thereof, and approximately four squares. A pair of frame legs 30 are coupled to both ends of the frame bar 20 while forming a pipe-shaped cross section.

In such a mask frame, the present invention forms a cutout portion 26 which is cut to a predetermined length in a state coinciding with the surface of the side edge 24 at both end sides 22 of the frame bar 20, and the frame leg 30 End portion of the) forms an inclined portion 32 inclined downward from the outside to the inside, and the frame leg 30 enters the cutout portion 26 of the frame bar 20 so that the inclined portion 32 is formed. The outer surface of the frame leg 30 exposed through the side and the side surface 24 of the frame bar 20 is formed by a spot welding. Also, preferably, the inclination angle θ of the inclined portion 32 of the frame leg 30 is maintained at an angle of 30 degrees to 50 degrees.

The present invention has a structure that can be welded to the welding gun 40 through the inclined portion 32 of the frame leg 30 can be bonded to the side edge 24 of the frame bar 20 by spot welding, Since the welding surface is composed of one surface and spot welding is possible, the welding operation is simplified and the welding time is shortened compared to the conventional four-sided all around welding. In particular, the heat affected zone due to welding can be significantly reduced. The variation of can be minimized.

In addition, according to the present invention, since the end of the quadrangular pipe-shaped frame leg 30 is exposed to the outside to expose the inside, it is not necessary to form a separate gas discharge hole.

5 and 6 show a welding state of the frame assembly according to the present invention, in which the outer surface of the frame leg 30 is welded to the side edge 24 of the frame bar 20 according to the present invention. As a result, the compressive rigidity of the frame bar 20 can be increased. For example, when the long side of the shadow mask 4 is welded to the upper surface of the frame bar 20, the shadow mask 4 is stretched and the frame is compressed and bonded, and then the frame is decompressed, the shadow mask 4 It is common to compensate for the domming of the shadow mask 4 due to the electron beam impingement, and after welding, the force that tensions the shadow mask 4 compresses both frame bars 20 in a direction facing each other. Will act as. In this case, the frame bar 20 should be designed to sufficiently overcome the compressive force, and structurally, both ends of the free end of the frame bar 20 are less vulnerable to compression resistance than the middle portion. This vulnerability is ameliorated by the present invention. That is, in the present invention, as shown in FIG. 5, since the outer surface of the frame leg 30 broadly supports the side edges 24 of the frame bar 20, the arrow direction compression of the frame bar 20 is sufficiently performed. I can support it.

As described above, according to the mask frame assembly for a color cathode ray tube according to the present invention, since the frame bar and the frame leg are each spot-welded with only one surface, the welding heat affected zone can be significantly reduced as compared with the conventional four-sided all-round welding. The distortion of the frame can be reduced.

While doing so, the present invention has an effect of improving the compressive rigidity of the frame bar because the outer surface of the frame leg supports the side of the frame bar in a very wide range.

In addition, in the present invention, since both ends of the frame leg are opened and exposed, the manufacturing process is simplified and the working time can be shortened as compared with the conventional technology of forming a separate gas discharge hole in the frame leg.

Claims (2)

A pair of frame bars having a lower side and a side and having a shadow mask bonded to the upper surface of the side surface, and a pair of frame legs formed at both ends of the pipe-shaped cross-section, both ends of which are joined to the frame bar. In the mask frame assembly of the color cathode ray tube, On both ends of the frame bar, a cutout of a predetermined length is formed in a state coinciding with the side surface, and an end portion of the frame leg forms an inclined portion that slopes downward from the outside to the inside, Mask frame assembly of a color cathode ray tube, characterized in that the frame leg is joined by entering the outer surface of the frame leg exposed through the inclined portion and the side edge of the frame bar by spot welding. The method of claim 1, Mask angle assembly of the color cathode ray tube, characterized in that the inclination angle (θ) of the inclined portion of the frame leg maintains an angle of 30 degrees to 50 degrees.