JP2001325899A - Panel for cathode-ray tube and its molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a panel for a cathode-ray tube and its molding method, which enable molding of the opening edge face of the panel with precision for use for a sealing surface, without polishing it and to obtain a satisfactory sealing state having expected strength without generating a gap between a frit glass and the opening edge face of the panel at the time of sealing in conjunction with a funnel. SOLUTION: An opening edge face 16 for sealing a panel, by interposing frit glass in-between, is molded in sufficient precision for using for the sealing surface without polishing. An effective face 19 of the opening edge face 16 is formed over the entire periphery of the opening edge face 16 on a flat surface or a convex curved surface 32 which satisfies an expression 0<=h/W<=0.02, where h is the maximum value of a displacement amount, based on a line between an inner edge and an outer edge in an optional thickness direction on the effective surface 19, and W is a width of the effective surface 19 in the thickness direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube panel and a method of forming the same.

[0002]

2. Description of the Related Art A cathode ray tube comprises a substantially rectangular panel on which an image is projected, a funnel-shaped funnel and a neck formed behind the panel, and the panel and the funnel have frit glass between both opposing sealing surfaces. It is sealed with interposition. In this sealing, a slurry-like frit glass mixed with an organic solvent is applied on the sealing surface of the funnel, and after drying, a panel is placed on the panel with the sealing surface facing the baking process. Is performed by heating and melting the frit glass and flowing it between the sealing end faces.

[0003] A cathode ray tube panel is generally formed by press-forming molten glass. As shown in FIG. 4, molten glass (gob) is supplied to a bottom mold 11 on which the shell ring 10 is placed, and the plunger 12 is lowered to the final lowering position. The panel 13 is formed by pushing and expanding the molten glass into a space formed by the mold 11 and the plunger 12. Molded panel 1
3 comprises a face portion 14 and a skirt portion 15 standing substantially upright around the face portion, as shown in FIG.
The upper end of the opening end surface 16 is the opening end surface 1.
Reference numeral 6 denotes a sealing surface on which the funnel is sealed via the frit glass later. Therefore, in the above forming apparatus, the forming surface of the shell ring 10 includes, as shown in FIGS. 6A and 6B, a chamfered forming portion 18 that forms a chamfered portion 17 on the inner edge and the outer edge of the opening end face 16 of the panel. An effective surface forming portion 20 that forms an effective surface 19 excluding the chamfered portion 17
And a side wall 22 forming an outer surface 21 of the skirt 15 of the panel 13, and an inner surface 23 of the skirt 15.
Is formed by the side peripheral wall of the plunger 12. After pressing the molten glass, the plunger 12 is raised, the inner surface of the panel 13 is cooled, the shell ring 10 is removed, and the panel 13 is cooled again.
Remove 3.

[0004]

Conventionally, the effective surface of the opening end face of the cathode ray tube panel after press molding is polished,
A sealing surface was formed. However, such a polishing operation requires a special polishing apparatus and a large amount of polishing agent, is time-consuming and time-consuming and is not economical.Moreover, fine scratches due to polishing must be generated on the effective surface. From the viewpoint of maintaining the strength of the opening, it has been desired that the opening end face after molding is not polished and used as it is as a non-polished surface.
Therefore, regarding a cathode ray tube panel that can obtain a predetermined surface accuracy without polishing the opening end surface after molding, it has been performed to use the opening end surface after press molding as a sealing surface with the non-polished surface remaining unpolished. .

[0005] However, in the conventional cathode ray tube panel in which the opening end face after press molding is used as a sealing surface without being polished, as shown in FIG. , Frit glass 26 and panel 13
There is a problem that a gap 27 is easily formed between the open end faces 16 of the panel 13, and the gap 27 seals the effective surface 19 of the open end face 16 of the panel 13 in a state of being partially out of contact with the frit glass 26. The void 27 has an elliptical shape extending in the thickness direction of the opening end face 16 with the flow of the frit glass 26 in the firing step. Some reach a length of / 2. Therefore, the sealing portion 25 having the voids 27 does not have a sealing state having an expected strength, and the sealing portion 25 is not sealed during the firing process of the frit glass 26 or the internal exhaust process of the glass bulb in the manufacturing process of the cathode ray tube. There is a problem that the voids in the attachment portion 25 receive local stress, and the glass from the sealing portion 25 is broken. Further, the occurrence of such voids tends to increase relatively as the size of the panel increases in a cathode ray tube panel having a sealing surface in an unpolished state, and the above problem occurs as the size of the panel increases. Remarkable.

Accordingly, an object of the present invention is to provide a molding method in which the opening end face of a panel is formed with a molding precision to be used as a sealing face without being polished, and is sealed between a frit glass and the opening end face of a panel in sealing with a funnel. Without creating voids,
An object of the present invention is to provide a cathode ray tube panel capable of obtaining a good sealing state having an intended strength, and a method of forming the same.

[0007]

Means for Solving the Problems In view of the above problems and objects, the present inventors have made intensive studies and as a result, have found that a conventional cathode ray tube panel whose opening end face is used as a sealing surface without being polished is used. In the effective surface of the opening end face, a slight dent having a depth of 0.05 to 0.25 mm is generated along the wall thickness direction, and a gap generated between the frit glass and the opening end face of the panel is: It has been found that this is due to a slight dent in the effective surface of the opening end face.

That is, since the temperature of the CRT panel cooled in the cooling step after the press forming by the plunger decreases from the outer surface, the outer surface is cooled, while the inner glass is still at a high temperature. In state. Therefore,
The heat shrinkage differs between the outer surface and the inside of the panel, and the shrinkage of the glass inside the skirt portion causes shrinkage in a direction perpendicular to the opening end face, as shown in FIG. It has been found that slight depressions 28 are formed in 19. Since the depth of the recess increases in proportion to the thickness of the skirt and the length of the skirt, it is generally considered that the larger the panel size, the deeper the recess on the effective end face of the opening. Also, as shown in FIG.
Among the opening end surfaces 16 having a substantially rectangular outline, the opening end surface 16 in the vicinity of the corner portion 31 which is a joining area between the long side 29 and the short side 30 of the panel 13 has an effective surface 19 as compared with the opening end surface 16 in other regions. Is more likely to occur. The reason for this is that when the molten glass is pushed and expanded by the press pressure of the plunger, the molten glass first
Next, it is pushed out in the short side direction, and finally the molten glass extends from below and left and right near the corner,
The skirt portion near the corner portion has a shorter contact time with the plunger than other portions, and the glass inside the skirt portion near the corner portion has a higher temperature than the other portions. For this reason, since the difference in the amount of thermal shrinkage of the glass between the outer surface and the inner portion described above also increases, it is considered that dents are likely to occur particularly on the effective surface of the opening end surface near the corner.

When a panel for a cathode ray tube in which such a dent is formed on an effective surface of an opening end face is placed on a sealing surface of a funnel coated with frit glass, as shown in FIGS. The effective surface 19 of the opening end surface 16 of the frit glass 26 comes into contact with the frit glass 26, and the frit glass 2
When the fluid 6 flows, the air bubbles are trapped at the interface between the opening end face 16 and the frit glass 26 by the recess 28 of the effective surface 19 of the opening end face 16, and the frit glass 26
As a result, the air bubbles cannot be completely removed even by the flow, and as a result, a sealing state is established in the sealing portion via the gap 27.

The present invention has been made based on the above considerations and knowledge, and has a molding precision with a molding precision that allows an open end surface of a panel to which a funnel is sealed via frit glass to be used as a sealing surface without being polished. The effective surface of the opening end surface is the maximum value of the displacement amount from a straight line connecting the inner edge and the outer edge in any thickness direction on the effective surface, h, the effective surface width in the thickness direction is A panel for a cathode ray tube, wherein W is a flat surface or a convex curved surface satisfying 0 ≦ h / W ≦ 0.02, which is formed over the entire periphery of the opening end surface.

Further, the present invention is characterized in that the maximum value h of the displacement from a straight line connecting the inner edge and the outer edge in an arbitrary thickness direction on the effective surface is substantially at the midpoint on the straight line. I do.

Further, the present invention provides a molding apparatus having a shell ring, wherein a panel having an open end surface at an upper end is molded.
The amount of dent displacement of the effective surface of the opening end face of the molded panel is measured, and the effective surface forming portion of the opening end face of the shell ring is modified into a concave shape in accordance with the amount of dent displacement of the effective surface of the opening end face. A method for forming a panel for a cathode ray tube, comprising forming a panel having a sealing surface with an open end face unpolished after forming by a forming apparatus using a processed shell ring.

[0013]

The cathode ray tube panel of the present invention is formed with a molding accuracy that allows the opening end surface to be used as a sealing surface without being polished, and the effective surface of the opening end surface has an arbitrary thickness on the effective surface. When the maximum value of the displacement from a straight line connecting the inner edge and the outer edge in the thickness direction is h, and the effective surface width in the thickness direction is W, a flat surface or a convex surface satisfying 0 ≦ h / W ≦ 0.02. In the step of sealing with the funnel, the effective surface of the open end face of the panel comes into contact with the frit glass applied on the sealing face of the funnel in the step of sealing with the funnel by being formed over the entire curved surface of the open end face. When the frit glass flows by heating, good flow of the frit glass along the effective surface becomes possible without entrapping air bubbles at the interface between the effective surface and the frit glass. If h / W is less than 0, air bubbles are trapped at the interface between the effective surface of the open end face and the frit glass due to the depression of the effective surface of the open end face, and the panel is sealed in a state where a gap is generated in the sealing portion. Be worn. Further, the panel taken out of the molding apparatus is transported to a post-process and stored after being processed in each process. Therefore, when h / W exceeds 0.02, the contact area of the convex curved surface becomes small at the time of handling such as transporting the panel, placing the panel in a post-process, or storing the panel. Micro scratches and chippings are likely to occur. Such a scratch on the opening end face is not a problem in the sealing process with frit glass, but in the exhaust process of the glass bulb in the later manufacturing process of the cathode ray tube, since the internal exhaust is performed while performing the heat treatment, Since a considerable stress is applied, glass breakage due to scratches on the effective surface of the opening end surface is likely to occur.

Further, by setting the maximum value h of the displacement amount of the effective surface substantially at the midpoint in the thickness direction of the effective surface at the opening end surface of the cathode ray tube panel, the frit glass flows when the frit glass flows. This is more preferable because the flow from the opening end surface of the skirt portion along the inner and outer surfaces of the skirt portion is performed in a well-balanced manner.

Further, according to the present invention, a panel having an open end face at an upper end is formed by a forming apparatus having a shell ring.
The amount of dent displacement of the effective surface of the opening end face of the molded panel is measured, and the effective surface forming portion of the opening end face of the shell ring is modified into a concave shape in accordance with the amount of dent displacement of the effective surface of the opening end face. A panel having a sealing surface without polishing the open end face after molding is molded by a molding apparatus using the processed shell ring. Thereby, by taking into account in advance the amount of dent displacement of the effective surface at the opening end surface of the panel due to the cooling action of the glass after press forming, the effective surface forming portion of the shell ring is modified and processed, thereby opening the opening end surface of the panel. A panel for a cathode ray tube which is formed without being polished with a molding precision to be used as a sealing surface and which does not cause a dent due to a cooling action which causes a void in a sealing portion on an effective surface of an opening end surface. be able to.

[0016]

The present invention will be described below with reference to examples.

FIG. 1 is an enlarged cross-sectional view showing the vicinity of an opening end portion of a 20-inch size generally rectangular cathode ray tube panel according to the present invention, and FIG. 2 is an explanatory view showing a method of forming the cathode ray tube panel according to the present invention. Note that parts and members that are the same as those described above will be described using the same reference numerals.

In this embodiment, the opening end face 16 of the panel is used.
Is formed with a molding precision to be used as a sealing surface without being polished, and the inner edge and the outer edge of the opening end surface 16 are chamfered portions 1.
7, 17 are formed. These chamfers 17, 17
The effective surface 19 of the opening end face 16 excluding the above is formed as a convex curved surface 32 over the entire circumference of the opening end face 16 of the substantially rectangular panel 13. The convex curved surface 32 has a maximum value h of 0.07 mm of the displacement amount from a straight line connecting the inner edge and the outer edge of the effective surface 19 of the opening end surface 16 in the thickness direction, and the effective surface 19 has a width W of 6.
It is molded so that h / W is 5 mm and h / W is 0.01. The maximum value h of the amount of displacement of the convex curved surface 32 is located substantially at the midpoint on the straight line, that is, at the midpoint in the thickness direction of the effective surface 19.

The cathode ray tube panel 13 is formed by the following method.

As shown in FIG. 2A, the panel 13 is formed by a forming apparatus having a shell ring having a horizontal effective surface forming portion, and after cooling, the panel 13 is recessed in the effective surface 19.
With respect to the opening end face 16 in which is generated, the dent displacement amount with respect to the reference horizontal plane is measured over the entire circumference of the opening end face 16. This measurement is performed by, for example, a contact type three-dimensional coordinate measuring machine (CMM), and the measurement is performed on the plurality of panels 13 over the entire circumference of the opening end face 16. In the case of this embodiment, the amount of dent displacement in the effective surface 19 of the open end face 16 of the panel 13 is 0.01 mm on the long side 29 side and the short side 30 side of the panel 13 in FIG. Side 30
Gradually increases from the edge of
7 mm. Next, based on the measurement result of the dent displacement amount of the effective surface 19 with respect to the reference horizontal plane, the effective surface forming portion 20 of the shell ring 10 is modified over the entire circumference. Correction processing of the effective surface forming part of the shell ring
8.0 mm in diameter, almost corresponding to the opening end surface forming part
The end is R1 mm and the bottom is the effective surface 1 of the panel 13
Using a plurality of straight end mills having various convex curvature surfaces corresponding to the dent displacement amount with respect to the reference horizontal plane of No. 9, the effective surface forming portion of the shell ring is subjected to dent processing corresponding to the dent displacement amount in the panel 13. Apply. In this case, when the effective surface 19 is formed on the convex curved surface 32 of the same height over the entire circumference of the opening end surface 16 of the panel 13 as in the present embodiment, the dent displacement of the panel 13 To the quantity
In consideration of the convex height of the convex curved surface of the panel 13, the effective surface forming portion of the shell ring may be subjected to dent processing.

FIG. 2 (b) shows that the vicinity of the opening end face 16 of the panel 13 is formed by the forming apparatus using the shell ring 10 in which the effective surface forming portion 20 is recessed as described above. It shows the state where it is. In this case, panel 1
The effective surface 19 of the opening end surface 16 of the panel 3 is 0.08 mm on the long side 29 side and the short side 30 side of the opening end surface 16 of the panel by the effective surface forming portion 20 of the shell ring 10, and the corner portion 31.
Is formed into a convex curved surface 32 of 0.14 mm. Thereafter, the plunger 12 is raised, the inner surface of the panel 13 is cooled, the shell ring 10 is removed, and the panel 13 is cooled again.
Is taken out, and through a process such as slow cooling, the effective surface 19 of the opening end face 16 is contracted in a concave direction, so that the opening end face 16
Is formed on a convex curved surface 32 having a height of 0.07 mm over the entire periphery of the open end face 16 of the panel.

The open end face of the panel formed by the shell ring as described above is used as a sealing face without being polished, and the frit applied on the sealing face of the funnel in the sealing step with the funnel. When the effective surface of the opening end surface of the panel comes into contact with the glass, air does not become trapped at the interface between the effective surface and the frit glass, and even during firing, the frit glass does not entrap air, as shown in FIG. The frit glass 26 smoothly flows along the effective surface 19 formed into the convex curved surface 32 at the opening end surface 16 of the above, and a good sealing shape and a good sealing state are obtained.

Table 1 shows that, for a cathode ray tube panel of a 20-inch size, 50 panels of the examples 1 to 5 according to the present invention and 50 panels of the comparative example were produced. It shows the exhaust process damage rate. In Examples 1 to 5 and Comparative Example 2, the maximum value h of the displacement amount of the effective surface formed on the convex curved surface at the opening end surface of the panel is substantially at the midpoint in the thickness direction of the effective surface. It is molded to be located.

The frit step breakage rate in the table means that the frit glass (mixture ratio of frit 10: vehicle 1) dispersed in an organic solvent (vehicle) is applied on the sealing surface of the funnel, dried, and dried. The panel is placed on top with its sealing surfaces facing each other, and baked at 450 ° C. for 40 minutes. In this calcination step, the sealing portion is formed due to a gap formed between the frit glass and the opening end face of the panel. 4 shows the breakage rate that caused glass breakage from the glass. Further, the evacuation process breakage rate means that after sealing the panel and the funnel to form a glass bulb, the inside of the glass bulb is removed from the neck tube at the rear of the funnel.
The evacuation was performed while heating at 0 ° C. for 10 minutes, and the breakage rate in which breakage occurred with the vicinity of the sealed portion as the origin was shown.

[0025]

[Table 1]

In Comparative Example 1, the three panels were closed in a state where air bubbles were trapped at the interface between the effective surface and the frit glass due to the depression of the effective surface of the opening end surface, and as a result, a gap was generated in the sealing portion. During the firing process of the frit glass or the exhaust process of the glass bulb, the void portion was locally stressed, and the glass was broken from the sealing portion.

Further, in Comparative Example 2, no destruction occurred in the firing step of the frit glass, but destruction occurred in one glass bulb in the subsequent exhausting step of the glass bulb with the vicinity of the sealing portion as the origin. occured. As a result of further observing the destruction origin near the sealing portion, the effective surface of the opening end face of the panel has been scratched during handling such as transporting and placing the panel. It was found that crack propagation occurred from the starting point, leading to destruction.

On the other hand, Embodiments 1 through 1 according to the present invention
The cathode ray tube panel of No. 5 does not generate a gap between the frit glass and the opening end face of the panel, and can obtain a good sealing state having an intended strength at the sealing portion. In the frit step and the exhaust step, No damage occurred in either case.

In the present invention, the effective surface of the opening end face of the panel is not only formed on the convex curved surface over the entire circumference of the opening end face, but also, for example, as shown in the fourth and fifth embodiments. A flat surface and a convex curved surface may be partially formed in the circumferential direction of the end surface. In actual continuous production of panels, due to the effects of various conditions, individual products may have some variation, so even if the aim is to form the effective surface as a flat surface, actually Considering that there is a possibility that some products may have dents in the opening end surface, from the viewpoint of mass production stability, it is necessary to form the effective surface after cooling into a slightly convex curved surface. It is better to aim. Also, the convex height of the convex curved surface of the panel is not limited to the same height over the entire circumference of the opening end surface.

[0030]

As described above, according to the cathode ray tube panel and the method of molding the same of the present invention, the opening end surface of the panel is molded with the molding accuracy to be used as a sealing surface without being polished, and the panel is sealed to the funnel. In the process, there is an excellent effect that a good sealing state having an intended strength can be obtained in the sealing portion without generating a gap between the frit glass and the opening end face of the panel.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of the vicinity of an opening end portion of a panel for a cathode ray tube according to the present invention.

FIG. 2 is an explanatory view showing a method for forming a panel for a cathode ray tube according to the present invention.

FIG. 3 is an explanatory view showing a sealed state of a panel for a cathode ray tube according to the present invention.

FIG. 4 is an explanatory view showing a general method of forming a panel for a cathode ray tube.

FIG. 5 is an overall view of a panel for a cathode ray tube.

6A is an explanatory view showing a molding state near an opening end face of a general cathode ray tube panel, and FIG. 6B is an explanatory view showing a vicinity of an opening end face of the cathode ray tube panel.

FIG. 7 is a cross-sectional view showing a sealed state of a conventional cathode ray tube panel.

FIG. 8 is an enlarged cross-sectional view of the vicinity of the opening end surface of the cathode ray tube panel.

FIG. 9 is an explanatory view showing a sealed state of a panel for a cathode ray tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Shell ring 13 Panel 16 Open end surface 19 Effective surface 20 Effective surface forming part 25 Sealing part 26 Frit glass 27 Void 28 Depression 32 Convex curved surface

Claims (3)

[Claims] 1. An opening end face of a panel to which a funnel is sealed via frit glass is formed with a molding precision to be used as a sealing face without being polished, and an effective face of the opening end face is formed by the effective face. When the maximum value of the displacement from a straight line connecting the inner edge and the outer edge in an arbitrary thickness direction on the surface is h, and the effective surface width in the thickness direction is W, 0 ≦ h / W ≦ 0.02. A panel for a cathode ray tube, wherein the panel is formed over the entire circumference of the opening end surface on the flat surface or the convex curved surface. 2. A maximum value h of a displacement amount from a straight line connecting an inner edge and an outer edge in an arbitrary thickness direction on an effective surface is substantially at a middle point on the straight line. The panel for a cathode ray tube according to the above. 3. A molding apparatus having a shell ring,
A panel having an open end surface at the upper end is formed, and the amount of dent displacement of the effective surface of the open end surface of the molded panel is measured, and the effective surface of the open end surface of the shell ring is determined according to the amount of dent displacement of the effective surface of the open end surface. A panel for a cathode ray tube, wherein a molded portion is modified into a concave shape, and a panel having a sealing surface with an unpolished open end surface after molding is molded by a molding device using the modified shell ring. Molding method.