KR19990027068A - Flat mask for shadow mask manufacturing of cathode ray tube - Google Patents

Abstract

The present invention provides a flat mask for manufacturing a shadow mask of a cathode ray tube having an Invar steel sheet portion and an AK steel sheet portion.

The flat mask includes a flat mask 36 'comprising: an Invar steel plate portion 46 blacked by a flat outline A' which has developed a shaping outline A of the shadow mask 36 in the molded state; And an inner boundary line of the overlapping portion 47 overlapping 3 to 4 mm inward from the outline of the shadow mask 36 and the outline of the invar steel plate portion 46, and the inva steel portion 46. It is characterized in that it is composed of the AK steel sheet portion 48 is welded at the overlapping portion 47 and the integrally with the Invar steel sheet portion 46.

Accordingly, in the effective screen portion, the thermal expansion can be reduced to suppress the doming phenomenon. In the molding outline portion, the moldability can be improved to suppress the springback and the reverse curvature phenomenon to the effective screen portion.

Description

Flat masks for shadow mask manufacturing of cathode ray tubes

The present invention relates to a flat mask for manufacturing a shadow mask of a cathode ray tube made of an Invar steel sheet portion and an AK steel sheet portion. In particular, the molding of the skirt portion is improved to maintain a predetermined curvature in the effective screen portion and to suppress the doming phenomenon due to thermal expansion. The present invention relates to a flat mask for manufacturing a shadow mask of a cathode ray tube.

Generally, a cathode ray tube, as shown in FIG. 1, has a vacuum bulb divided into a panel 12, a funnel 13, and a neck 14, and inside the neck 14. And an shadow gun 16 mounted on the sidewall of the panel 12.

A fluorescent surface 20 is formed on the inner surface of the face plate 18 of the panel 12, and the electron beams 19a and 19b emitted from the electron gun 11 are focused and accelerated by various lens systems, and the anode button 15 It is greatly accelerated by the high voltage applied through the deflection yoke (17) and deflected by the deflection yoke (17) and passed through the apertures or slits (16a) of the shadow mask (16) to the fluorescent surface (20).

The shadow mask 16 described above is formed of a rolled steel sheet of thin Invar steel, rimmed steel, or killed steel (AK steel), as shown in FIGS. The effective screen portion 26 in which the apertures or slits 16a, which are the plurality of electron beam passing holes, are formed so that the electron beam emitted from the light can pass therethrough, and the invalidity in which the electron beam passing holes do not pass through the outer portion of the effective screen portion 26. It is composed of the screen portion 28, by pressing the flat mask (16 ') is formed into a shadow mask (16), it is detachable to the stud pin of the panel 12 by being assembled with the frame and holder (not shown) To be installed.

However, when the shadow mask 16 of FIG. 1 is made of an Invar steel plate as shown in FIG. 2 into a flat mask 16 ', after heat is applied at about 200 ° C, the foam is formed into a predetermined shape. Due to the elastic force, the skirt portion formed by the invalid screen portion 28, i.e., spring back phenomenon occurs, which makes it difficult to assemble with the frame, and the effective screen portion 26 also resists the repulsive stress against the spring back. As a result, the curvature portion in the reverse direction is locally formed, so that the gap with the fluorescent surface is not constant locally.

In addition, in the case of the flat mask 16 of the AK steel plate as shown in Fig. 3, since the plastic force is superior to that of the Invar steel sheet, the forming moldability is good, so that the effective screen portion 26 'has a flat mask 16 of Fig. Compared to '), the spring back of the skirt and the localized reverse curvature of the effective screen portion 26' are less, but the amount of domming due to thermal expansion increases in the effective screen portion 26 ', making it difficult to apply to CDT of 14V or more. there is a problem.

Accordingly, the present invention is to solve the above-described problems, taking advantage of the above-described Invar steel sheet and AK steel sheet to form a reduction in the amount of ming due to thermal expansion as well as forming the spring back and the local reverse curvature phenomenon of the skirt portion and At the same time, an object of the present invention is to provide a flat mask for manufacturing a shadow mask of a cathode ray tube that can be formed into a shadow mask capable of suppressing the doming phenomenon.

1 is a schematic plan view in partial cross section of a color cathode ray tube;

2 is a plan view of a flat mask for manufacturing a shadow mask of a cathode ray tube made of a conventional Invar steel plate,

3 is a plan view of a flat mask for producing a shadow mask of a cathode ray tube made of a conventional AK steel sheet;

4 is a plan view of a flat mask for producing a shadow mask of a cathode ray tube according to the present invention;

5 is a perspective view of a shadow mask molded into a flat mask for producing a shadow mask of the cathode ray tube according to the present invention.

Explanation of symbols for the main parts of the drawings

10 cathode ray tube (CRT) 11 electron gun

12: panel 13: funnel

14 neck 15 anode button

16: shadow mask 16 ': flat mask

18: panel face plate 19a, 19b: electron beam

20: fluorescent screen (screen) 26, 26 ', 46: effective screen portion

46 ': curved portion 48': skirt portion

46: Invar steel sheet portion 48: AK steel sheet portion

In order to achieve the above object, a flat mask for manufacturing a shadow mask of a cathode ray tube according to the present invention includes a plurality of in-line three-color electron beams emitted from an electron gun passing through three-color dots or stripe-type phosphors on a fluorescent surface to form pixels. An effective screen portion having apertures or slits and an invalid screen portion through which an electron beam does not pass are formed outside the effective screen portion, and are formed in a flat mask for cathode ray tube formed by a shadow mask having a predetermined shape by press molding. : Invar steel sheet part blanked by a flat outline that has developed the forming outline of the shadow mask in the molded state; And an inner boundary line of the overlapping portion overlapping 3 to 4 mm inward from an outline of the shadow mask and an inner portion of the invar steel sheet portion, and welded at the overlapping portion with the invar steel sheet portion to be integrated with the invar steel sheet portion. It is characterized by consisting of a steel plate portion.

In this way, the thermal expansion can be reduced in the effective screen portion to suppress the doming phenomenon, the moldability can be improved in the molding edge portion to suppress the springback and the reverse curvature phenomenon in the effective screen portion.

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

Figure 4 shows a flat mask for producing a shadow mask of the cathode ray tube according to an embodiment of the present invention as a plan view, Figure 5 shows a perspective view of a shadow mask molded with a flat mask for producing a shadow mask of the cathode ray tube of the present invention.

In FIG. 4, the flat mask 36 'for producing a shadow mask of the cathode ray tube according to the present invention is composed of an Invar steel sheet portion 46 and an AK steel sheet portion 48. As shown in FIG.

The invar steel sheet portion 46 is blanked and provided with a plane outline A 'which has developed the forming outline A of the shadow mask 36 in the molded state as shown in FIG. 48 is formed as a part between the outline where the shadow mask 36 is deployed and the inner boundary of the overlapping portion 47 overlapping 3 to 4 mm inward from the outline of the invar steel plate portion 46, and is blanked in the same manner. Prepared. It is preferable that the above-mentioned Invar steel plate part 46 is formed with a plurality of apertures or slits 16a described above by etching in advance.

The Invar steel sheet portion 46 and the AK steel sheet portion 48 thus prepared are integrally welded by laser welding, seam welding, or spot welding at the overlap portion 47 to form the flat mask 36 '. To form.

In addition, according to the flash butt to butt resistance welding method, the electrode can be welded at a time by using the electrode over the pole of the overlapping portion 47, which is preferable in terms of productivity.

The flat mask 36 'thus manufactured is processed by press molding into a predetermined shape consisting of the curved portion 46' and the skirt portion 48 'as in the prior art.

At this time, the shadow mask 36 formed as described above is as shown in Figure 5, because the skirt portion 48 'of Figure 5 is excellent in formability as the AK steel sheet portion 48 of Figure 4 Spring back phenomenon is significantly reduced compared to Invar steel. Therefore, the stress transmitted to the curved portion 46 'is also reduced by the reduced springback, so that the reverse curvature phenomenon of the curved portion 46' is almost eliminated.

In addition, as a result of applying a predetermined heat to the curved portion 46 'of the shadow mask 36, the thermal expansion rate was low, indicating that the doming phenomenon was greatly reduced.

The shadow mask 36 described above is assembled in a conventional manner together with a holder in a frame, mounted on the panel 12 as shown in FIG. 1, and then manufactured into a cathode ray tube through subsequent processes.

Since the cathode ray tube manufactured as described above is greatly reduced in springback of the skirt portion 48 ', the assembling property with the frame is excellent, and the image quality is improved by removing the doming phenomenon.

According to the configuration and operation of the flat mask for manufacturing the shadow mask of the cathode ray tube according to the embodiments of the present invention described above, the flat mask 36 'which can only use the advantages of the Invar steel sheet portion 46 and AK steel sheet portion 48 ), It is possible to remove the dominant phenomenon by improving press formability and reducing the coefficient of thermal expansion and at the same time to remove the reverse curvature of the curved portion 46 'and further improve the assembling with the frame and improve the image quality. It can be effective.

Claims (2)

An effective screen portion 46 having a plurality of apertures or slits 16a through which inline type three-color electron beams emitted from an electron gun pass to form a pixel by colliding three fluorescent dots or stripe-shaped phosphors on the fluorescent surface 20. In the flat mask for cathode ray tube, an invalid screen portion 48 in which an electron beam does not pass is formed outside the effective screen portion 46, and formed into a shadow mask 36 having a predetermined shape by press molding. An invar steel sheet portion 46 blanked by a planar outline A 'which has developed the forming outline A of the shadow mask 36 in the molded state; And an inner boundary of the overlapping portion 47 overlapping 3 to 4 mm inward from the outline of the shadow mask 36 and the outline of the invar steel plate portion 46, and overlapping with the invar steel plate portion 46. Flat mask for shadow mask manufacturing of the cathode ray tube, characterized in that it is composed of an AK steel sheet portion 48 welded in the portion 47 and integral with the Invar steel sheet portion 46. 2. The flat mask of claim 1, wherein the poles are welded and leveled simultaneously by flash butt to butt resistance welding in the overlapping 47.