JPH027495B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for sealing a neck of a cathode ray tube and a stem on which an electron gun is mounted, and particularly to a method suitable for sealing when the neck is thick.

The conventional method of sealing the neck and stem of a cathode ray tube is as shown in Figure 1A, by inserting a stem 2 whose outer diameter is smaller than the inner diameter of the neck 1 into the neck 1 and heating the neck with a burner frame 3. The neck melts, and due to the surface tension of the glass, the pressure of the frame, and the gravity acting on the flare 5, the diameter of the melted neck becomes smaller and the wall thickness becomes thinner, causing the flare to drop, as shown in Figure B. Similarly, the neck and stem are welded together at the sealing part 4. Next, as shown in Figure C, the vicinity of the lower end of the stem is heated with a burner to burn out the neck and finish by baking and rounding the sealing part 4.

However, in recent years, there has been a trend to increase the thickness of the neck in order to absorb the X-rays generated by the electron gun, or to reduce the diameter of the neck in order to save electricity, making it difficult to obtain the desired amount of air gap between the neck and the stem. As a result, when the neck and stem are welded together, the thickness of the neck becomes thicker than desired, making it difficult to bake and round the sealed portion. One solution to this problem is to reduce the wall thickness in advance only near the sealing part of the net, but this method requires preliminary processing, increases the cost, and is difficult in practice.

The present invention aims to provide a method for sealing the stem of a cathode ray tube without the above-mentioned difficulties, and further provides a stem sealing method that improves the accuracy of the length after sealing and reduces defects caused by glass pieces of the cathode ray tube. The purpose is to

In order to achieve the above object, in the present invention,
After welding a relatively thick neck and stem, the area near the welded area was stretched by a predetermined dimension to reduce the thickness of the neck, and then the sealing part was baked and rolled.

The present invention will be explained in more detail with reference to the drawings. The outer diameter of the stem 11 shown in FIG. 2A is 29.1 mm, and the neck inner diameter is 24.0 mm. At the bottom end 12 of this net,
There is no flare as shown in Figure 1A, and the cut is in a straight line. First, the lower end of the net is heated with the burner frame 3 to melt it. In this case, the stem 21 may be in contact with the lower end of the neck, but it is easier to heat the lower end of the neck if a certain gap is left. Next, the stem 21 is crimped onto the lower end 12 of the neck as shown in FIG. 2B. Of course, at this time, if the stem 21 is cold, it will crack, so the stem must also be heated to around its melting point. When the lower end 12 of the neck is heated and melted, it shrinks somewhat to have an outer diameter of, for example, 28.0 mm and an inner diameter of 23.0 mm. If the outer diameter of the stem 21 is selected to be around the middle of these values, for example 25.5 mm, the shape of the sealing portion will be desirable. Of course, the stem diameter is adjusted to 11 before heating.
Although sealing can be achieved by setting the outer diameter to 29.1 mm, which is the same as the outer diameter, or more, the above value was the optimum value according to the results of the inventor's experiments. Further, the outer diameter of the stem must be larger than the inner diameter of the lower end 12 of the neck (23.0 mm) during heating. After welding the stem 21 to the lower end 12 of the neck 11 in this way, if the stem 21 is moved and stretched by a predetermined distance near this welded point,
As shown in FIG. 2C, the wall thickness near the bottom end 12 of the neck became thinner, making it easier to bake and roll the sealing portion. In addition, when moving the stem, if the stem is stopped at a predetermined position, the length from the reference line of the funnel (not shown) to the stem, that is, the sealing length, can be kept constant, and a large quantity of uniform products can be produced. can be made to In addition, the extraneous neck parts that occur in the conventional working method shown in FIG. 1 are eliminated, and this eliminates the possibility of debris entering the interior of the cathode ray tube and causing malfunctions.

As explained above, according to the present invention, it is possible to easily seal the stem to a thick neck or to a thin neck, which was difficult with conventional techniques, without requiring a specially shaped neck. It can be realized inexpensively. Further, the present invention is not limited to the above-mentioned embodiments. For example, when sealing the stem in a neck with a flare that allows easy insertion of an electron gun as shown in FIG. By moving the sealing portion downward by a predetermined amount, the sealing portion can be easily formed into a desired shape. However, in this case, the problem of generation of netsku fragments remains.

[Brief explanation of drawings]

FIGS. 1A to 1C are explanatory diagrams of a conventional stem sealing method for a cathode ray tube, and FIGS. 2A to 2C are explanatory diagrams of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 11...Neck according to the present invention, 12...Neck lower end, 21...Stem according to the present invention.

Claims (1)

[Claims] 1 In the sealing process between the glass neck of the cathode ray tube and the glass stem equipped with an electron gun, after welding the glass neck and the glass stem without flare,
A method for sealing an electron gun stem of a cathode ray tube, characterized in that the vicinity of the welded portion is stretched by a predetermined dimension to reduce the thickness of the glass neck portion, and then the sealing portion is baked and rolled.