JPS63298936A - Manufacture of shadow mask structure - Google Patents

Abstract

PURPOSE:To make it possible to apply a specific even tensile force to a shadow mask by fixing the shadow mask holding the tensile force to a frame on condition that the stress is inflicted in the inside direction of the frame. CONSTITUTION:A frame 2 is positioned and loaded on the substrate 1 of a welding unit. Then push rods 4 enforced in the inside direction by springs 3 are contacted to the outer periphery of the frame 2, and the frame 2 is pressed to the inside being given a specific amount of bending. Then a shadow mask 5 is loaded on the frame 2, and heated from its upper side by a panel heater 8. Keeping in such a condition, the mask 5 is welded by a welder almost at the center of the upper end of the frame 2 along all the periphery. After the welding is completed, the shadow mask structure is picked up. As a result, since the stress is inflicted in the inside direction to the frame 2, a tensile force operates to expand outward. Since this outward tensile force of the frame 2 sets off the tensile force to the inside of the mask 5, a specific even tensile force is applied to the shadow mask.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a shadow mask structure.

Frame l with tension applied to special 6 and shadow mask
This relates to a method of manufacturing a stretched shadow mask structure.

[Conventional technology]

The shadow mask used in color cathode ray tubes has a color selection function of phosphors coated in a mosaic pattern on the fluorescent surface of the panel, but when the electron beam collides with it, it thermally expands and deforms. This may impair the color selection function.

As a solution to this problem, a stretching type shadow mask structure is known, for example, as shown in Japanese Patent Laid-Open No. 61-80735, in which a shadow mask is stretched on a frame under tension.

[Problem that the invention seeks to solve]

In the above-mentioned prior art, the frame is simply fixed by applying tension to the shadow mask in the previous state. There was a problem.

An object of the present invention is to provide a method for manufacturing a shadow mask structure that can apply a predetermined uniform tension to a shadow mask.

[Means for solving problems]

The above object is achieved by securing the tensioned shadow mask to the frame while applying an inward stress to the frame.

[Effect]

Since stress is applied to the frame in the inward direction, a tension force is exerted on the frame that tends to expand outward. The tension in the outer direction of the frame cancels out the tension in the inner direction of the shadow mask, so that a predetermined uniform tension is applied to the shadow mask.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. A cross-sectional frame 2 is positioned and placed on a substrate 1 of a welding device. Next, a push rod 4 urged inward by a spring 3 is applied to the outer periphery of the frame 2 to push the frame 2 inward and bend it by a predetermined amount. The push rods 4 are arranged so that uniform stress is applied to each side of the frame 2, for example, two on each side, ie, eight in total, and are indicated by arrows A, A2, . . . in FIG. B
, , B , , C , , C , , D , , Rub the parts indicated by I to bend them in the direction of the arrow. Next, a shadow mask 5, which is a thin metal plate with a large number of electron beam passage holes 5a, is placed on the frame 2. In this case, since the shadow mask 5 is thin and easily bends vertically, the shadow mask 5 is pulled in eight directions (vertical, horizontal, and diagonal) with enough tension to make the shadow mask 5 horizontally curved. That is, the top 7, which is biased outwardly by the spring 6, is pulled outwardly.

Then, the shadow mask 5 is heated to about 150° C. from the upper surface of the shadow mask 5 by a panel heater 8 that emits far infrared rays. In this case, since the frame 2 has a large heat capacity and receives little direct infrared rays, the temperature rises by only a negligible amount. If necessary, a shielding plate 9 may be placed to shield infrared rays. With the shadow mask 5 heated in this way, the frame 2
The shadow mask 5 is continuously welded over the entire circumference from approximately the center of the upper end 2a using a welding machine (not shown). In FIG. 2, two-dot chain lines indicate welding points.

When the shadow mask structure is taken out after welding is completed, the temperature of the shadow mask 5 drops and tension is applied to the shadow mask 5#. After that, the excess portion around the shadow mask 5 is removed.

In this way, the heated and expanded shadow mask 5 is fixed while applying stress in the inward direction to the frame 2, so that the frame 2 has a tension that tends to expand outward.

This tension in the frame 2 offsets the tension caused by the shadow mask 5 cooling and causing the shadow mask 5 to become stiff inside. As a result, a predetermined uniform tension is applied to the shadow mask 5.

In the above embodiment t, the frame 2 is made of, for example, SCM445 made of chromium molybdenum steel, and has an upper width of 5 mm in cross section.
1FIm, lower width 10m, height in order of 10, overall outer diameter is 279 mm horizontally and 2101 mm high! It was formed into an X. The shadow mask 5 is, for example, a steel plate with a thickness of 0.025 mm.
Electron beam passing holes 5a having a diameter of about 0.121 mm were formed over the entire surface except for the periphery so that they were aligned at intervals of approximately 0.26 mm and the rows were spaced at an angle of 60 degrees. Also, the panel heater 7 is 1.5KW 400 x 300tm
Two heaters were placed side by side and placed about 70 mx away from the shadow mask 5 so that the center was slightly raised.

This panel heater 7I can heat the shadow mask 5 to about 150° C. in a heating time of several tens of seconds.

Note that the frame 2 is not limited to the aforementioned chromium molybdenum steel, and the shadow mask 5 is not limited to the aforementioned ordinary steel plate. In particular, when it is desired to reduce thermal expansion, the frame 2 and shadow mask 5 may be made of a material with a low expansion coefficient, such as nickel steel (amber) containing 36 nickel.

Furthermore, if the frame 2 is made of iron-nickel alloy containing 42% nickel and the shadow mask 5I is made of umber, the thermal expansion coefficient of the frame 2 is large in the operating temperature range of the shadow mask 5 - 40 to 100 degrees Celsius. Tension can be applied to the mask 5I in a desired direction. In this way, it is desirable to select a combination of materials in which the material for the frame 2 has a slightly thicker coefficient of thermal expansion within the operating range. However, if there is a large difference in the coefficient of thermal expansion between the frame 2 and the shadow mask 5, when the shadow mask structure reaches a temperature of about 450°C during the color cathode ray tube manufacturing process, the shadow mask material may exceed its yield point. This should be avoided as it may loosen the tension and cause deformation.

〔Effect of the invention〕

According to the present invention, since deformation of the frame due to the tension of the shadow mask is prevented, stable and uniform tension is applied to the shadow mask.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the method for manufacturing a shadow mask structure according to the present invention, and FIG. 2 is a perspective view of the shadow mask structure obtained by the method shown in FIG. 2...Fam, 3...Spring, 4...
- Push rod, 5...Shadow mask, 5a...Electron beam passage hole. Fig. 1 2: Frame Fig. 2 2: Frame 5: 5 Yadomasufu 50:

Claims (1)

[Claims] 1. In a method for manufacturing a shadow mask structure in which a shadow mask having a large number of electron beam passage holes formed in a thin metal plate is stretched on a frame under tension, the frame is subjected to stress in an inward direction. . A method for manufacturing a shadow mask structure, characterized in that the shadow mask to which tension is applied is fixed to the frame.