JPS6086740A - Crt and manufacture of the same - Google Patents

Abstract

PURPOSE:To eliminate defect at the fabric sealing part and easily control manufacturing by coating the side wall part in the axial direction for 2mm. or more from the joining surface and said joining part with the fabric sealing material and melting and hardening said fabric sealing material. CONSTITUTION:The panel side wall 3 and funnel 4 are coated with a flit glass mixture for the area defined by the end of joining part including the joining part of them and the point separated by about 5mm. from said end along the side wall. Both joining surfaces are stacked opposite to each other and is placed under the temperature rise with the predetermined temperature gradient within the furnace in order to crystallize the flit glass. Thereafter, it is placed under the temperature drop with the predetermined temperature gradient and then it is taken out to the outside. An excessive flip glass appearing in both sides of joining surface is not protruded and almost flat fabric sealing part can be obtained. Thereby, generation of defective wet angle can be reduced resulting in large margin on control of manufacturing, generation coefficient of crack can also be reduced and as a result mechanical strength of fabric sealing part can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cathode ray tube and a method for manufacturing the same, and particularly to a cathode ray tube envelope.

[Technical background of the invention and its problems]

The envelope of a cathode ray tube, which generates an electron beam and makes it impinge on a fluorescent surface to produce an image, generally has a structure as shown in FIG.

That is, its constituent members have a fluorescent surface on the inner surface (not shown)
A panel (1) consisting of a face plate (2) for projecting images and a side wall (3) approximately parallel to the tube axis direction.
, the large diameter end (
4a) and a small diameter end (4b), an end (5a) corresponding to the small diameter f4 (4b) of the funnel (4), and the other end (5b) having a flare. It is composed of a neck part (5) consisting of a neck part (5), a base (7) in which a conductive lead (8) is implanted, and a stem (6) consisting of a tip tube (9) connected to this base (7).
Of these, the side wall (3) of the panel (1) and the funnel (
4) On the side wall part, there is a mold match line (Mp) that is the maximum outer diameter of each split mold during molding.
and (MF) have k. These envelope components are typically made of glass, and the procedure for forming the envelope is as follows. First, the funnel (4) and the ends (4b) and (5b) of the neck part (5) are brought into direct contact. Next, the ends of the panel (1) and the funnel (4) (
3a) and (4a) are fused together via a sealing member. After that, the conductive lead (8) is inserted into the neck part (5) of the stem (6) connected to the required electron gun (not shown), and the neck part is melted at the end of the base (7) of the stem (6). Finally, the tip tube (9) of the stem (6) is evacuated to a full vacuum inside the tube, and the tip tube (9) is completely fused and sealed 1.

However, in a monochromatic cathode ray tube that does not have a shadow mask (not shown) for a color selection function, the panel (1) and the funnel (4) are generally directly fused together. In the case of a color cathode ray tube, a shadow mask having a large number of electron beam passage holes is attached to the panel (1), and a multicolor emitting fluorescent surface is sequentially formed one color at a time by light exposure through the shadow mask. . Therefore, since the operation of attaching and detaching the shadow mask to the panel (1) is added, the panel (1) and the funnel (4) are often joined via a sealing member after the fluorescent surface is formed. This is to protect the parts inside the pipe near the joint including the shadow mask from the high temperatures of direct fusion, and to join at as low a temperature as possible. Such an envelope is required to have sufficient mechanical strength against the pressure difference caused by evacuating the inside of the tube.

In other words, panels generally have a substantially rectangular shape when viewed from the tube axis direction, and although the stress applied to each part differs, it has sufficient explosion resistance, including each corner, which is considered to be the weakest, even if a specified external impact is applied. It is required to have compressive strength.

FIGS. 1 and 2 show a method of joining the panel (3) and both end surfaces (3a) and (4a) of the funnel (4). For example, as a sealing member,
A solder glass called frit glass as shown in Japanese Patent No. 39010 is used. As a sealing method, a frit glass GO) mixture as shown in Japanese Patent Publication No. 49-28649, for example, is applied to the center of the end face (4a) of the funnel (4) and dried. Next, Ir was applied between the ends (3a) of the panel side wall (3) through the frit glass layer (3) and baked at a temperature of about 450° C. for 30 to 60 minutes to complete the sealing. After sealing, as shown in FIG. 2, a convex fixed shape is obtained in which the frit glass protrudes from both ends of the sealed portion. Generally, the thickness of the frit glass between both end faces (3a) and (4a) is 0.
05 to 0.3 mm is considered to be good in terms of strength, and the excess frit glass protrudes to form a protruding part (11). In this case, the end of the protruding part (6) and the panel side wall (
3) and the funnel (4), the so-called wetting angle, is considered to be obtuse in terms of strength.

However, in order to perform the sealing work with sufficient mechanical strength, it is necessary to reduce the spacing due to variations in the characteristics of the frit glass and the coating amount, as well as the flatness and slope of both end faces on the panel side and the funnel side. Alternatively, it is necessary to fully manage many conditions such as variations in firing temperature.

Among these shapes of the sealing portion, the shape that is particularly disadvantageous in terms of strength is one in which the wetting angle θ with the side wall becomes an acute angle due to the sagging a of the protruding portion η of the frit glass, as shown in Fig. 3. be. A large stress concentration occurs in this part due to vacuum evacuation within the envelope, and in severe cases, it may implode during evacuation. Furthermore, even if the side wall of the envelope is reinforced with metal bands or the like to prevent explosions, it may become the starting point for cracks when subjected to mechanical shock from the outside, resulting in implosion.

Next, as shown in FIG. 4, a piece of frit glass containing bubbles 03) on the protruding portion side is used. The larger the protruding part (11) of this bubble (131) is, the thicker it becomes, and some large bubbles with a diameter of 2 rMl are observed. can easily become a starting point for cracks.

In addition, when tightening and reinforcing the side wall of the envelope with a metal band, the protruding part may come into contact with other objects and cause an obstruction, or the protruding part may come into contact with other objects while handling the tube. The strength may deteriorate due to chipping or scratches.

[Purpose of the invention]

The present invention has been made in view of the above points, and an overall purpose of the present invention is to provide a cathode ray tube and a method for manufacturing the same, which can eliminate defects in the sealing parts of the panel part and the funnel part, and can easily manage the manufacturing process. do.

[Summary of the invention]

The present invention applies a sealing member to a thickness of 2+ nm or more from at least one joint surface of a panel and a funnel in the tube axis direction along the side wall, or in addition to this, a sealing member is further applied to the joint surface. The material is coated and the sealing part is melted and fixed to facilitate manufacturing control during sealing, and the wetting angle between the end of the part protruding from the joint surface and the side wall is an obtuse angle.
The purpose is to prevent the inclusion of large bubbles, and to ensure that the protruding height of the protruding portion of the sealing member is such that either the panel or the side wall of the funnel has sufficient mechanical strength as compared to the other.

[Embodiments of the invention]

Examples of the present invention will be described in detail below.

The present invention is the same as the conventional one except for the vicinity of the sealing portion of the panel and the funnel, so a description of the overall structure of the envelope will be omitted.

FIG. 5 shows a panel side wall (3) based on the first embodiment of the present invention.
and the vicinity of the joint surfaces (3a) and (4a) of the funnel (4).

The width of the joining surface between the panel side wall (3) and the funnel (4) is approximately 8 degrees, and the angle between the side wall and the pipe axis from the end of the joining surface to each mold match line is approximately 1.5 degrees. . In addition, the maximum gap when the two bonded surfaces are overlapped is approximately 0.
．． It was 2 miles Mn.

In such a panel side wall part (3) and funnel (4), is the joint surface between the two? Apply the frit glass mixture from the edge of the joint surface to about 5 inches along the side wall.

Frit glass I coating thickness after drying is approximately 0.1 to 0.
．． There are three teachers.

As frit glass, Pb075%, ZnOlO%
A general glass mixture is prepared by mixing isoamyl acetate or butyl acetate containing 1.0% by weight of nitrocellulose as a vehicle with a frit glass having a composition of 10% B203, 0.2% Si, and 2% NaO and having an average particle size of about 7 μm. did. Next, the two bonded surfaces are placed on top of each other, and the temperature is raised at a predetermined temperature gradient in a firing furnace and held at a maximum of 440°C for 40 minutes. After crystallizing the frit glass, the temperature is lowered at a predetermined temperature gradient to 345°C or less. I took it out of the furnace. The shape after sealing is shown in Figure 7. That is, the protrusion caused by the excess frit glass on both sides of the bonding surface did not have a convex shape as in the conventional case, but a substantially smooth sealed portion (9) was obtained. In such a sealing part, the thickness of the protruding part is extremely thin, so even if bubbles exist, they are at least as small as 0.3 mm or less. Also, since the protruding part is almost smooth, there is little risk of damage during handling, and since it is located in the tube axis direction from the maximum outer diameter of the nozzle and the funnel, that is, the line connecting the mold match line, it is suitable for explosion-proof metal. There is no risk of contact damage to the belt.

As a second example, the thickness of frit glass after coating and drying was 0.3 to 0.5 in the same shape as in the first example.
In the case of mm, the shape of the protruding portion after sealing was such that the maximum protrusion height of the protruding portion due to the excess frit glass was approximately 0.8 bulge.

In this case, the bulge is larger on one side of the panel and the side wall of the funnel, that is, the lower funnel side is larger, and the wetting angle between the bulge end and the side wall is an obtuse angle, and the frit glass on the side wall surface is smooth. (=It was a continuous shape. That is, the excess frit glass protrudes along the frit glass previously applied to the side wall surface, so it blends in well and the angle is not acute.

The above embodiments are very effective when the integrity of the tube-side joint surfaces is maintained to some extent. However, if the bonding surfaces have poor alignment, or if there is a difference in the bonding surfaces or widths between the two, sufficient sealing strength may not be obtained. For example, the maximum gap when the two joint surfaces are overlapped is 0.35++m.
If the same sealing as in the first embodiment is applied to the positive one, there will be a portion where the bonding surface is not sufficiently filled with the frit glass, and cracks are likely to occur from this portion.

Therefore, as a third example, the panel side wall (3) and the funnel f4) were sealed as shown in FIG.

The width of the joint surface (4a) of the funnel part (4) is approximately 9.5 mm, while the joint surface (3a) of the panel side wall (3) has a height difference of approximately 1 mm in the outer diameter direction. The effective width of the joint surface (3a) is approximately 7 cm. Also, both joint surfaces (3a) and (4
a) eThe maximum gap when stacked is 0.4mm.
Met. In this sealing part shape, as in the first embodiment, the frit glass (1e has a thickness of O, l after drying) extends from the end of the joint surface to about 5 mm along the side wall including the joint surface.
Apply the frit glass mixture to a tone of wn to 0.3. Next, the joint surface on the funnel (4) side (
A frit glass surface is formed in the center of 4a). Thereafter, the sealing was completed in the same manner as in the first example.

As shown in Fig. 9, the shape after sealing is such that the maximum protrusion height of the protruding part of the frit glass in the area without steps is about 1.
It exhibits a bulge of 2 tlIIll, and occupies an average of about 35 inches of the entire circumference at 4.5 locations on average out of 5 test examples. This bulge does not directly reach the side wall of the funnel, and the wetting angle at the end is obtuse, so the bulge has a shape that smoothly connects to the entire funnel without any influence.

As a fourth example, similar to the third example, no frit glass was applied to the panel side, and frit glass was applied only to the funnel side and sealed.

After sealing, the protruding portion of the frit glass exhibited a bulge as shown in Figure 3 on the funnel side and Figure 9 on the funnel side, but there was no problem with the wetting angle. In this case as well, the frit glass is heated and melted on the side of the lower funnel part where it flows.

Since the frit glass is applied thinly in advance, wetting is good and the protrusion height of the protruding portion does not become as large as in the conventional case.

In the above examples, the coating length of the frit glass along the side wall portion from the edge of the joint surface was approximately 5 mm, but the wetting angle of the excess frit glass protruding portion is important because the wetting angle at the beginning of the protruding portion is at least 2 mm. It was confirmed that if the coating length was longer than that of a gourd, the wetting angle would be approximately obtuse.

In each of the above examples, the appearance of the sealed portion was good, such as sagging, but the mechanical strength and strength deterioration due to the bubbles that may have been contained were comprehensively evaluated by conducting destructive tests. We conducted a thorough evaluation. Conventionally, the cathode ray tube was applied to a 10-inch 90-degree deflection color cathode ray tube, which had a high incidence of cracks especially from the frit glass in the sealing part. A diameter of 50 mm is placed approximately 50 mm from the maximum outer diameter at a corner of the face grating, which is said to have weak surface strength.
75 ~ standard impact for a bell using a steel ball sound of about 5001 in the dark?
A strength test was carried out. As for the samples, there were 30 pieces each of the conventional type shown in FIGS. 2 and 3, the first example (the second example), and the fourth example.

As a result, cracks occurred from the frit glass in 18 conventional glasses, and one of them imploded.

Bubbles in the frit glass were observed in 15 pieces that were broken, and the size of the bubbles ranged from 0.4wn to 1.5 gourds in diameter, and 2 of them
In the case of the first example, cracks were generated from the sagging part of the frit glass on the inside of the tube.On the other hand, in the case of the first example, bubbles were observed in the frit glass and cracks occurred in the frit glass. The bubble sizes are 0.3 mm and 0.5 mm in diameter.
ms and was small. In this test example, the crack occurrence rate was only about 7% compared to 60 inches for the conventional product, indicating a significant improvement in mechanical strength.

Next, in the case of the fourth example, bubbles were observed in the frit glass in four cases, and cracks occurred in the frit glass. The size of the bubbles was one with a diameter of 0.3 tan, two with a diameter of 0.5wn, and one with a diameter of 08. The crack occurrence rate was approximately 13 times, indicating that the strength was also significantly improved.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to significantly reduce poor wetting angle, which is a defect in the sealing part between the panel part and the funnel part, and increase the manufacturing control margin. By making the bubbles smaller and reducing the number of them, the rate of crack occurrence is significantly reduced.
The mechanical strength of the sealed portion can be increased.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing all the components of the cathode ray tube envelope;
FIG. 2 is a schematic cross-sectional view of the main parts to explain the conventional antacid process, and FIGS. 3 to 5 are schematic cross-sectional views of the main parts to explain the shape after the conventional antacid process. FIG. 6 is a schematic sectional view of the main parts for explaining the sealing process according to the first embodiment of the present invention, and FIG. 7 is a schematic sectional view of the main parts for explaining the entire shape after sealing in FIG. 6. , Fig. 8 is a schematic sectional view of the main part for sealing (c) according to the third embodiment of the present invention, and Fig. v is ``''\ figure, ,) After sealing. Shape □ Description A, Yes. Main part. Schematic cross-sectional view. (1,) --- Panel (2) --- Face plate (
3)...Side wall part (4)...Funnel (3a),
(4a)... Joint agent Patent attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2 Figure 8 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Scope of Claims] l) A panel having a face plate for transmitting an image and a side wall portion extending along the central axis direction of the face plate substantially coinciding with the tube axis of the peripheral portion of the face plate; , in a cathode ray tube comprising an envelope consisting of a funnel-shaped funnel, one end of which is connected to a cylindrical neck portion and the other end of which is joined to a side wall end of the panel via a sealing member, the joining of the panel and the funnel; The protruding height of the sealing member protruding in the outer circumferential direction from the outer peripheral edge of the surface to the side wall 5 is greater than the other one of the side wall portion of the panel and the funnel portion, and the protruding portion of the sealing member A cathode ray tube characterized in that the angle formed between the end and the side wall portion is an obtuse angle. 2) A protruding height of the sealing member from the side wall portion is on the tube axis side with respect to a line connecting the maximum outer diameter direction height of the side wall portion of the funnel and the panel. A cathode ray tube according to scope 1. 3) A panel having a face plate for transmitting an image, a side wall portion along the central axis direction of the face plate that substantially coincides with the tube axis of the peripheral portion of the 7 Ace Freight, and a neck having a cylindrical shape at one end. A method for manufacturing a cathode ray tube comprising an envelope consisting of a funnel-shaped funnel connected to a side wall end of the panel and the other end joined to a side wall end of the panel via a sealing member, the method comprising: Apply the sealing member two times or more in the direction along the tube axis along at least one side wall portion, heat the joining surfaces of the panel and the funnel facing each other, and melt and fix the sealing member. A method for manufacturing cathode ray tubes that has all the following characteristics. 4) A panel having a face plate for transmitting an image, a side wall portion extending along the central axis direction of the face plate that substantially coincides with the tube axis of the peripheral portion of the face plate, and a neck having a cylindrical end at one end. In the method for manufacturing a cathode ray tube, the envelope comprises a funnel-like funnel, the other end of which is connected to a side wall of the panel through a sealing member, the joining surface of the panel and the funnel being and applying the sealing member to the entire surface of the tube in the direction along the tube axis for two or more periods, further applying the sealing member to the joint surface of at least one of the panel and the funnel, A method for manufacturing a cathode ray tube, characterized in that the joint surfaces of the panel and the funnel are heated while facing each other, and the sealing member is melted and fixed. 5) The width of the sealing member of the side wall of at least one of the panel and the funnel in the tube axis direction (2) is 5 or more. A method for manufacturing a cathode ray tube as described in .