JPS6131936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shadow mask structure installed in a color picture tube and a method for manufacturing the same. Generally, a shadow mask structure 1 installed in a color picture tube has a perforated part 3 formed into a substantially spherical shape in which a large number of dot-shaped or rectangular openings 2 are regularly bored, as shown in FIG. A perforated part 5 consisting of a non-perforated part 4 provided around the perforated part 5;
It consists of a skirt part 6 connected to the peripheral edge of the mask frame 7, and a mask frame 7 having an L-shaped cross section to which the skirt part 6 is fixed at a plurality of points. However, since the shadow mask structure 1 as described above uses a thick and heavy mask frame 7 to support the shadow mask, it must be supported with a strong spring material or the like when it is installed inside a color picture tube. Furthermore, since the heat generated by the impact of the electron beam is transmitted to the mask frame 7, which has a large heat capacity, there is a drawback that mislanding due to thermal deformation of the shadow mask is likely to occur during the initial operation of the color picture tube. In order to eliminate these drawbacks, a shadow mask structure that does not use a mask frame as shown in FIG. 2 has been developed. That is, shadow mask structure 1
1 includes an effective part 13 in which a large number of dot-shaped or rectangular openings 12 are regularly bored, and an effective part 15 formed in a substantially spherical shape with a non-porous part 14 provided around the effective part 13; , a skirt 16 that is formed integrally with the effective part 15 and is bent along the periphery of the effective part 15 at a desired angle (approximately right angle in the figure) to the effective part 15; It consists of the effective portion 15 and a flange 17 bent at a desired angle (approximately right angle in the figure). Such a shadow mask structure 11 can be integrally molded and is provided with mechanical strength by the flange 17, but as it is, its mechanical strength is inferior to the shadow mask structure 1 having the mask frame 7 shown in FIG. . As a result, during the assembly process of the color picture tube, the effective part 15 in particular is easily deformed, making it difficult to obtain sufficient color purity and white uniformity for a color picture tube. The present invention has been developed in view of the various drawbacks of the prior art described above, and an object of the present invention is to provide a shadow mask structure without a mask frame and having sufficient mechanical strength, and a method for manufacturing the same. Next, one embodiment of the present invention will be described with reference to FIG. That is, the shadow mask structure 21 has an effective part formed into a substantially spherical shape, including a perforated part 23 in which dot-shaped or rectangular openings 22 are regularly bored, and a non-perforated part 24 provided around the perforated part 23. 25, which is integrally formed with the effective part 25, and which is integrally formed with the effective part 25.
A skirt 26 is bent at a desired angle (approximately right angle in the figure) to the effective portion 25 along the periphery of the skirt 26 , and
The flange 27 is bent in the opposite direction to the effective portion at a desired angle (approximately right angle in the figure), which is substantially the same as that shown in FIG. 2, but this embodiment is different. It is characterized in that a hardened portion is formed from approximately the center of the skirt 26 to the flange 27 in the direction of the arrow 29 from the broken line 28. Methods for forming this hardened portion include a chemical hardening method and a physical hardening method. One of the former methods, that is, a chemical hardening method, is a carburizing method. An example of this carburizing method will be explained with reference to FIG. 4. First, as shown in FIG .
Up to 6, carburizing agent 3 consisting of charcoal and carbon barium etc.
When the so-called carburizing box 31 held at 0.0° C. is placed in a heating furnace 33 as shown in Figure b and heated to a predetermined carburizing temperature of about 880 to 950°C, oxygen and carbon in the air inside the box are released. Carburizing takes place in the resulting CO and _CO3 atmosphere. That is, carbon and CO ₂ react to produce CO, which is decomposed on the surface of the shadow mask structure 21 to produce activated carbon as 2COC+CO ₂ , and this carbon is
It melts and invades the surface of the desired part, and is generated as 2COC + CO ₂ on the surface of this shadow mask structure 28.
The CO ₂ returns to the carbon and this process is repeated to perform carburization. The shadow mask structure 21 hardened by such a carburizing method is hardened by increasing the amount of carbon in the desired portions, so as mentioned above, the integrally formed shadow mask structure is mechanically more stable than the shadow mask structure with a mask frame. By eliminating the cause of poor strength, we were able to obtain an extremely strong shadow mask structure. The above-mentioned hardening should be performed from the skirt 26 to the flange 27, and the effective part 2
5, small irregularities occur in the spherically formed effective part 25 due to distortion due to infiltration of carbon, resulting in an error in the distance between the phosphor screen of the color picture tube (not shown) and the effective part 25 of the shadow mask. The desired accuracy cannot be obtained, which causes deterioration of the color purity of the color picture tube. As mentioned above, chemical quenching is an effective method for partially quenching, but it is well known that in addition to the above-mentioned carburizing methods, there is also a liquid carburizing method that uses sodium cyanide, etc. There is. In addition, as a physical hardening method, flange 27
Possible methods include high-frequency heating and rapid cooling. As for the parts to be hardened, depending on the design of the shadow mask structure, it is conceivable to harden both the skirt 26 and the flange 27 as described above, or to harden only the flange 27. As mentioned above, according to the present invention, the integrated shadow mask structure itself has sufficient mechanical strength without requiring a mask frame, so it is inexpensive and has excellent color purity characteristics and white uniformity characteristics. It has become possible to obtain a color picture tube having the following characteristics, and its industrial value is extremely large.

[Brief explanation of the drawing]

1 and 2 are diagrams showing conventional shadow mask structures. FIG. 1 is a perspective view showing one having a mask frame, FIG. 2 is a perspective view showing one integrally formed, and FIG. FIG. 4 is an explanatory perspective view of an embodiment of the shadow mask structure of the present invention, and FIG. 4 is an explanatory diagram showing an example of a chemical hardening method, and FIG. Simplified sectional view, Figure b is a simplified sectional view showing the state shown in Figure A placed in a heating furnace. 1 , 11 , 21 ...Shadow mask structure, 5,
15, 25... Effective part, 6, 16, 26... Skirt, 17, 27... Flange.

Claims (1)

[Scope of Claims] 1. A plurality of openings are formed integrally with the effective part and the effective part, and at least one diffraction part is formed on the periphery of the effective part at a desired angle with the effective part. A shadow mask structure comprising a skirt and/or a flange that is bent and has a hardened part. 2. The shadow mask structure according to claim 1, wherein the hardened portion is formed so as to surround the effective portion. 3. An effective part in which a large number of openings are regularly bored, and a skirt or flange that is formed integrally with the effective part and is bent at least once at a periphery of the effective part at a predetermined angle with the effective part. 1. A method for manufacturing a shadow mask structure, characterized in that a hardened portion is formed by a chemical method and/or a physical method. 4. The method for manufacturing a shadow mask structure according to claim 3, wherein the chemical method is a carburizing method.