KR100274899B1 - Mask frame for cathode ray tube_ - Google Patents

Abstract

PURPOSE: To provide a mask frame that can reduce the initial amount of domming by shortening the heat transfer time from the shadow mask due to the electron beam to the mask frame to realize color purity and white improvement.

Configuration: The present invention provides a skirt portion 44 in which the shadow mask 34 is welded and formed parallel to the tube axis direction of the cathode ray tube, and extending from the upper edge of the skirt portion 44 adjacent to the shadow mask 34 and having an electron beam. It consists of the facing part 42 in which the substantially rectangular opening part 52 which E) can pass is formed.

Effect: The time required for the initial domming process is shorter than the heat transfer time that has been transferred to the mask frame after the complete heating of the conventional shadow mask, thereby reducing the initial domming amount of the shadow mask, thereby optimizing white defects and color purity.

Description

Mask frame for cathode ray tube

The present invention relates to a mask frame for a cathode ray tube, and more particularly, to a cathode ray tube capable of optimizing initial thermal expansion in order to improve white defects caused by a domming phenomenon caused by an electron beam injected from an electron gun impinging on a shadow mask. Relates to a mask frame.

The cathode ray tube converges the electron beam emitted from the electron gun and employs a shadow mask so that each of the cathode ray tubes is landed on the red, green, and blue phosphors of the face panel, so that predetermined images and icons are displayed.

The cathode ray tube is a face panel and the channel is coupled to the inside of the vacuum to facilitate the movement of electrons, the inside of the neck of the channel is equipped with an electron gun and a deflection yoke for deflecting the electron beam is mounted on the outer periphery. The inner face of the face panel has a structure in which a mask frame equipped with a shadow mask is suspended by stud pins by springs, and red, green, and blue phosphors are patterned on the inner face.

Thus, the electron beam scanned by the electron gun is deflected by the deflection yoke and is passed through the hole holes of the shadow mask corresponding to the red, green, and blue phosphors and landed on the phosphors of the face panel.

On the other hand, the shadow mask on which the mask frame is mounted is welded by the MIFA method or the MOFA method according to the welding method, and the shadow mask 2 is particularly shown in FIGS. 4 and 5. Is welded to the inner side of the mask frame 4, the opening 6 formed in the mask frame 4 is combined with the face panel 8 and the mask frame 4 in consideration of the path of the electron beam E. FIG. Since it is located on the same horizontal plane as the lower end of the face panel 8 in the state and at the same time wider than the effective screen portion 10 of the shadow mask 2, the shadow mask due to the heating by the collision of the electron beam (E) When (2) is dosed, the electron beam E impinges only on the shadow mask 2, resulting in slow heat transfer to the mask frame 4.

At this time, about 15 to 18% of the electron beam E penetrates through the hole 12 of the shadow mask 2 and 82 to 85% impinges on the surface of the shadow mask 2 to heat the shadow mask 2. As a result of the thermal expansion, a domming phenomenon occurs in which the shadow mask 2 is convexly deformed, resulting in color purity and white defects. This problem is compensated by the heat transferred to the mask frame after heating the shadow mask to the spring, but the heat transfer to the mask frame due to the electron beam (E) impinging on the shadow mask is slow and white defects due to the initial domming It is pointed out that this problem is worse.

Disclosure of Invention The present invention devised to solve this problem is to provide a mask frame capable of realizing color purity and white by reducing an initial amount of domming by shortening a heat transfer time from a shadow mask due to an electron beam to a mask frame.

For this purpose, the shadow mask is composed of a skirt portion welded and formed parallel to the tube axis of the cathode ray tube, and a facing portion extending from an upper edge of the skirt portion adjacent to the shadow mask and having a generally rectangular opening through which the electron beam can pass. .

Here, a bead is formed in the corner portion of the inner surface where the facing portion and the skirt portion contact each other, thereby improving the strength of the mask frame.

The size of the opening portion may be formed to be substantially the same as the size of the effective screen portion through which the electron beam passes.

In particular, the curvature of the facing portion is molded in the same manner as the curvature of the shadow mask.

1 is a side cross-sectional view showing a cathode ray tube equipped with a mask frame according to the present invention;

2 is a perspective view showing a mask frame according to the present invention,

3 is a view showing a path of an electron beam scanned into a mask frame according to the present invention;

4 is a perspective view showing a conventionally known mask frame.

Figure 5 is a side cross-sectional view showing a conventionally known cathode ray tube.

Explanation of symbols on the main parts of the drawings

20: face panel 22: channel

32: Spring 34: Shadow Mask

36: mask frame 38: mask hole

40: effective screen part 42: no study

44: upright part 46: skirt part

48: facing part 50: bead

52: opening EB: electron beam

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 shows a cathode ray tube equipped with a mask frame according to the present invention in a side cross-sectional view, Figure 2 shows a mask frame in a perspective view.

As can be seen from the figure, the cathode ray tube is a face panel 20 and the channel 22 is coupled to the inside of the vacuum to facilitate the progress of the electrons. The neck portion 24 of the channel 22 is equipped with an electron gun 26 and a deflection yoke 28 for deflecting the electron beam E is mounted on the outer circumference thereof. The blue phosphor and the black matrix are patterned, and the spurd pin 30 is provided on the inner surface.

A spring 32 is suspended from the spud pin 30, and the spring 32 is welded to a side of a mask frame 36 to be described later on which the shadow mask 34 is mounted.

The front surface of the shadow mask 34 is composed of an effective screen portion 40 and a non-hole 42 formed of a mask hole 38 through which the electron beam E passes. An upright portion 44 extending in parallel with the tube axis direction of the cathode ray tube is formed.

On the other hand, the mask frame 36 is formed with a skirt portion 46 parallel to the upright portion 44 of the shadow mask 34, and at the upper edge of the skirt portion 46, i.e., near the face panel 20, at the edge thereof. The face portion 48 extends with a certain curvature and is formed to have the same curvature as the inner surface curvature of the face panel 20, and thus may be molded differently according to the model thereof.

In particular, a bead 50 is formed at the inner edge where the skirt portion 46 and the facing portion 48 contact to reinforce the strength of the mask frame 36.

In addition, the facing portion 48 may have an opening 52 having a size corresponding to the effective screen portion of the shadow mask 34, as shown in FIG. 3, according to a feature of the present invention, thereby allowing the electron beam E to pass therethrough. Since the size of the opening 52 is the same as that of the effective screen portion 40, the electron beam E is completely scanned onto the effective screen portion 40 of the shadow mask 34 and at the same time, about 8% of the electron beam E The inner surface 48 of the mask frame 36 is to collide with each other.

Looking at the shadowing process of the shadow mask 34 in the cathode ray tube equipped with the mask frame 36 having such a structure, the electron beam E is 108% of the effective screen portion 40 in the electron gun of the neck portion (not shown). The emitted electron beam E is deflected by the deflection yoke and scanned to the effective screen portion 40 of the shadow mask 34.

At this time, 100% of the entire electron beam E is incident on the effective screen portion 40 and the remaining 8% is impacted inside the facing portion 48 of the mask frame 36. In particular, about 15 to 18% of the electron beam E incident on the effective screen part 40 passes through the mask hole 38 of the shadow mask 34 and lands with red, green, and blue phosphors of the face panel 20. To implement an image.

Here, the electron beam E that does not pass through the mask hole 38 and collides with the effective screen portion 40 heats and expands the shadow mask 34, and at the same time, an 8% electron beam that collides with the mask frame 36. (E) heat-expands the mask frame 36 so that the shadow mask 34 and the mask frame 36 heat-expand at about the same time during the initial domming process, so that the initial domming time is shorter than before.

As described above, the embodiment of the present invention substantially solves the conventional problems.

That is, the facing portion extending from the skirt portion of the mask frame is formed not on the channel side but on the face panel side, and the shadow mask is welded to the mask frame in a morphological manner, and the opening size of the facing portion is the effective screen portion of the shadow mask. As it is molded to the same size, 8% of the electron beam heats the mask frame so that the shadow mask and the mask frame are thermally expanded almost simultaneously.

Therefore, the time required for the initial domming process is shorter than the heat transfer time that has been transferred to the mask frame after the complete heating of the conventional shadow mask, thereby reducing the initial domming amount of the shadow mask, thereby optimizing white defects and color purity.

Claims (4)

In the cathode ray tube that the electron beam emitted from the electron gun passes through the effective screen portion of the shadow mask provided on the inner surface of the panel and landed on the fluorescent film to realize a desired image The shadow mask 34 is welded and formed parallel to the tube axis direction of the cathode ray tube, and extends from the upper edge of the skirt portion 46 adjacent to the shadow mask 34 and the electron beam E. A mask frame for a cathode ray tube, characterized in that it is composed of a face portion (48) in which an approximately rectangular opening (52) that can pass therethrough is formed. The mask frame for a cathode ray tube according to claim 1, wherein a bead is formed at an inner corner portion of the facing portion (48) and the skirt portion (46). The cathode ray tube mask frame according to claim 1, wherein the size of the opening portion 52 is the same as that of the effective screen portion 40 through which the electron beam E passes. 2. The mask frame for cathode ray tube according to claim 1, wherein the curvature of the facing portion (48) and the curvature of the shadow mask (34) are the same.