KR0133829Y1 - Chthode ray tube - Google Patents

Abstract

The present invention discloses an improved inner seal of color brown tubes.

Conventional inner seals can shield external magnetic fields, but there is a problem that shielding the ineffective electron beam or preventing the diffuse reflection does not deteriorate image quality and is difficult to assemble.

In the present invention, by forming a bending tab that is bent to the shadow mask side inside the inner shield, it is easy to assemble, achieves complete shielding without diffuse reflection of the ineffective electron beam, and also reduces the thermal effect.

Description

Inner Seal of Color Brown Tube

1 is a cross-sectional view of a color brown tube illustrating the construction and operation of a general inner shield,

2 is a partially enlarged cross-sectional view showing an example of a conventional inner shield,

3 is a partially enlarged cross-sectional view showing the inner shield according to the present invention.

* Explanation of symbols for main parts of the drawings

1: inner shield 4: bent tab

F: frame M: shadow mask

S: screen

The present invention relates to a color brown tube, and more particularly to an inner shield thereof.

Color CRT Tubes R, G, B are image display apparatuses for displaying a color image by selectively landing each electron beam on a screen of which phosphors R, G, B are made through color selection means. Accordingly, the path of each electron beam must be precisely matched to the color discriminating hole of the color discriminating means, for example, a shadow mask.

However, when the latitude of the sage used in the manufacturing site of the color CRT is different, slight deviation occurs in the path of the electron beam depending on the direction difference of the geomagnetic field. The influence of the geomagnetic is hardly a problem in the case of a black and white CRT, but in the case of a color CRT, the color purity is degraded and the image quality is deteriorated.

Accordingly, as shown in FIG. 1, an inner shield I of a funnel type is provided to cover the path of the electron beam B1 to shield the influence of geomagnetic or other external magnetic fields. The inner shield I is generally joined to the frame F of the shadow mask M by a clip K or by melting point.

However, such an inner shield I has a problem in that the electron beam B is diffusely reflected at the inner end and the inner end of the frame F to generate a double phase or a halation.

Accordingly, in the other conventional inner shield I 'shown in FIG. 2, an ineffective electron beam entering the outside of the effective region by forming a bending tab T bent upward of the inner end of the inner shield I'. Attempted to block (B2). However, in this inner shield I ', the electron beam B2 near the outermost end of the effective region is reflected toward the shadow mask M side, causing a problem of directly entering the clip. K) and the proximity of the welding head are difficult. In particular, it is difficult to check whether the matching with the frame F is made by the bending tab T, and assembly is very cumbersome.

Another common problem of the conventional inner shield I, I 'is that the shadow cannot be properly blocked by the ineffective electron beam B2 entering outside the effective area of the screen S and the shadow mast M. Purity drift due to heat is severe in the doming of the mask M or the like.

In view of these various problems in the related art, the object of the present invention is not only to perform the basic function of shielding the external magnetic field, but also to block the entry of the ineffective electron beam, to prevent the diffuse reflection, and to reduce the thermal effects of the shadow mask and the frame. In addition to killing, the assembly is extremely easy to raise the inner seal.

In order to achieve the above object, the inner seal according to the present invention is characterized in that a bending tab bent toward the shadow mask side is formed therein.

According to one feature of the present invention, the bending tab is configured to be seated on the aperture of the frame, allowing quick and easy matching of the inner shield and the frame.

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

In FIG. 3, a screen S formed of predetermined R, G, and B phosphors is provided on an inner surface of a panel P of a color brown tube, and a shadow mask M which maintains a predetermined distance from the screen S is provided. ) Is coupled to the frame (F) and supported by the panel (P). The inner shield I is coupled to the rear flange Ff of the frame F by a method such as a clip K or welding.

The inner shield I includes a shielding portion 2 surrounding the paths of the electron beams B1 and B2 to shield the external magnetic field as in the related art, and a coupling portion 3 coupled to the flange Ff of the frame F. And, according to the features of the present invention is provided with a bent tab (bent tab) 4 recorded on the shadow mask M side.

On the rear side of the frame F, an aperture in the form of a substantially rectangular screen S, which is a passage path of the electron beam B1, is formed inside the flange Ff. Preferably, the bending tab of the inner shield I is formed. The base of (4) comes into contact with the inner end of this aperture. Accordingly, simply placing the inner shield I on the frame F causes the inner shield I to be guided to the inclined surface of the bending tab 4 to be automatically seated in the correct position with respect to the frame F.

Also preferably, the tip of the bending tab 4 is positioned outside the effective area of the shadow mask M or the screen S as seen on the projection path of the electron beam B1. Accordingly, the unnecessary ineffective electron beam B2 is blocked from entering the shadow mask M side. In this case, the blocked ineffective electron beam B2 does not enter the shadow mask M side because the upper surface of the bent tab 4, that is, the reflecting surface faces upward, and is reflected toward the funnel side so that the double image or the halle is on the screen S. It will not cause the occurrence or the like.

In addition, since the bending tab 4 is downward, the proximity of the clip K or the welding head is not obstructed, and internal heat caused by the glass electrons that emits the screen S is also blocked by the bending tab 4 to prevent the frame F. Since no heat is input on the side, drift in image quality due to heat influence can be prevented.

As such, the present invention has a great effect on improving the image quality of the color CRT.

Claims (3)

In the inner shield of the color brown tube installed in the shadow mask frame to shield the external magnetic field, the inner side of the inner shield (I) is provided with a bent tab (4) bent toward the shadow mask (M) Inner seal of color brown tube to assume. According to claim 1, wherein the base of the bent tab (4) corresponding to the aperture of the frame (F), the inner shield (I) is seated on the frame (F) Inner sealed. The color-brown tube according to claim 1, wherein the tip of the bending tab 4 corresponds to the outer end of the effective area of the shadow mask M or the screen S as seen on the projection path of the electron beam B1. Inner seal of the.