JP2003197127A - Glass panel for cathode-ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass panel of high quality for a cathode-ray tube with a flat face part having excellent heat resistance by preventing the glass panel from causing breakage such as triangular cracking caused in heat treatment. <P>SOLUTION: This glass panel 1 for a cathode-ray tube is provided with the face part 3 of which radius of curvature of an outer surface on a diagonal axis X is 10000 mm or more. An inclined chamfered part 10 is formed at least at an outer side part in a prescribed range including the diagonal axis X in a seal end surface 5 of a skirt part 6. When the inclined chamfered part is formed along the whole circumference of the seal end surface 5, the inclined chamfered part 10 is provided with a large surface width along the prescribed range. This inclined chamfered part 10 is formed in a range of 5 mm or more and 100 mm or less from the diagonal axis X toward the length direction center part side of the sealed end surface of each side 8. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass panel for a cathode ray tube, and more particularly to a technique for suppressing damage to the glass panel during heat treatment in the cathode ray tube manufacturing process.

[0002]

2. Description of the Related Art As is well known, a cathode ray tube includes, as main glass parts, a panel on which an image is displayed and a funnel-shaped funnel. As shown in FIG. 5, the panel 1 is connected to a substantially rectangular face portion 3 provided with an effective screen for displaying an image and a face portion 3 through a blend R portion 4, and is used for joining with the funnel. Sealed end face 5
And a skirt portion 6 having. And
The skirt portion 6 is provided with each side portion 8 between the four diagonal portions 7, and a mold match line 9 which is generated by matching the press molding dies of the panel 1 and serves as the maximum outer diameter portion of the panel 1. have.

Generally, in the process of molding a glass panel 1 for a cathode ray tube of this type, a high temperature molten glass gob is supplied to a molding die and a plunger is lowered to push down the molten glass gob in the molding die. After that, the plunger is raised. After completion of this molding step, each predetermined operation including cooling and the like or each step is executed to obtain the glass panel 1 for a cathode ray tube shown in the same figure from the molten glass gob.

When manufacturing a color cathode ray tube,
The panel 1 and the funnel are sealed by interposing solder glass (hereinafter referred to as frit glass) between the sealing end surface 5 of the skirt portion 6 of the panel 1 and the sealing end surface of the funnel opposite to the sealing end surface 5. Is done. The glass bulb for a cathode ray tube manufactured in this way is used as a cathode ray tube which is a vacuum container by evacuating the inside to a vacuum, but at the time of its use, the inside is in a high vacuum. The stress due to the pressure difference between the inside and the outside is applied to the outer surface of the glass bulb which functions as the envelope of the cathode ray tube. Therefore, the glass bulb used for the cathode ray tube is designed such that its shape and wall thickness can withstand this stress.

More specifically, in this glass bulb for a cathode ray tube, when the inside of the glass bulb is formed into a high vacuum to form the cathode ray tube, the vacuum stress generated by applying atmospheric pressure to the cathode ray tube causes the panel 1 and the funnel. Since it becomes the maximum in the vicinity of the sealing end surface of No. 1, the wall thickness of the sealing end surface of the panel 1 and the funnel is determined so that the sealing strength required to withstand this vacuum stress can be obtained. In addition, the sealing end surface 5 of the panel 1
In order to obtain a sufficient sealing strength between the panel 1 and the funnel by the frit glass, each side portion 8 and each diagonal portion 7 are
The entire area corresponding to is a flat surface.

Further, when forming the sealing end surface 5 of the panel 1, the molding surface portion of the press die corresponding to the sealing end surface 5 is formed flat, and the sealing end surface having a desired flatness is press-molded. Is formed as an example. Apart from this, especially in a large-sized panel, the desired flatness may not be obtained due to thermal deformation after panel molding, and in such a case, by polishing the sealing end surface in a later step, Another example is to form a sealing end face having a desired flatness.

[0007]

By the way, in recent years, flattening of the outer surface of the face portion of the panel 1 has been promoted, and the radius of curvature of the outer surface on the diagonal axis X is 10,000.
A panel 1 (hereinafter referred to as a flat panel in this column) having a face portion 3 forming an effective screen of mm or more has been manufactured. When the flat panel 1 becomes a constituent element of the above-mentioned glass bulb for a cathode ray tube,
The stress due to the difference between the internal pressure and the external pressure applied to the face portion 3 becomes significantly larger than that of the curved panel (the panel that was the mainstream before the flat panel 1 was popularized). For this reason, the thickness of the face portion 3 of the flat panel 1 is usually set to be thicker than the thickness of the sealing end surface 5.

In this case, in the step of sealing the flat panel 1 and the funnel for manufacturing the glass bulb for the cathode ray tube, the frit glass is interposed between the sealing end surface 5 of the flat panel 1 and the sealing end surface of the funnel. Then, this is exposed to the internal atmosphere of a heat treatment furnace having a maximum temperature of about 450 ° C., whereby the sealing end faces of both are reacted with the frit glass to generate a chemical bond.

In the temperature rising process in the sealing step, the face panel 3 of the flat panel 1 has a substantially rectangular shape and the outer surface thereof is flattened, which causes a thermal expansion deformation of the curved panel. Different thermal expansion deformation occurs, and thermal stress concentration occurs in the diagonal portion 7 of the sealing end surface 5 of the flat panel 1. In this case, if a defect such as a minute scratch is present in the diagonal portion 7 of the sealing end face 5, a crack originating from the defect is generated due to the concentration of thermal stress, and the crack is generated in the temperature rising process. As it progresses, damage occurs in a triangular pyramid shape from the sealing end surface 5 of the diagonal portion 7 or its periphery to each side portion 8, and a phenomenon called a so-called triangular crack occurs.

The drawbacks such as the minute scratches are that when the flat panel 1 after molding is handled, for example, when the surface of the flat panel 1 is polished, the flat panel 1 is brought into contact with the sealing end surface 5 on a predetermined table. Which occurs due to contact or sliding between the sealing end surface 5 and other members in the process of fixing and fixing, or in the package when the flat panel 1 is packed and transported, or in various transport processes of the flat panel 1. is there. Even if the minute scratches and the like cannot be easily observed with the naked eye, there is a risk of causing damage such as triangular cracks due to the above-mentioned thermal stress concentration.

By the way, it can be said that the above-mentioned triangular crack is a problem peculiar to the flat panel 1 and cannot occur in the curved panel. That is, as described above, the flat panel 1 has the face portion 3 whose outer surface has a radius of curvature of 10000 mm or more on the diagonal axis X.
And a skirt portion 6 extending from the periphery thereof to the sealing end surface 5 which is the opening end through the blend R portion 4. Therefore, the expansion accompanying the application of heat to the flat panel 1 causes structural deformation as shown in FIGS. 6 and 7. 6 (a) and 6 (b) show the quadrant obtained by cutting the flat panel 1 along the major axis A and the minor axis B (see FIG. 5) along with the application of heat to the flat panel 1. This is a schematic representation of the mode of thermal expansion deformation that occurs as a result, and the arrows in the figure indicate the direction of deformation due to thermal expansion. Further, FIG. 7A is a schematic view of the periphery of the diagonal portion 7 of the sealing end surface 5 as viewed from a direction perpendicular to the face surface, and the dotted line in the figure schematically shows the shape at the time of thermal expansion deformation. FIG. 7 (b)
FIG. 4 is a schematic vertical cross-sectional view of the periphery of the diagonal portion 7 of the skirt portion 6 taken along the diagonal axis X, and the dotted line in the figure also illustrates the shape at the time of thermal expansion deformation.

Specifically, as shown in FIG. 6A, in the temperature rising process in the heat treatment process for sealing with the funnel 2, the center axis Z (tube axis) of the face portion 3 is blended. When thermal expansion occurs in the direction toward the R portion 4, that is, in the direction parallel to the outer surface of the face portion 3, one end of each side portion 8 of the skirt portion 6 is an open end, and thus FIG.
As shown in (b), the central portion of each side portion 8 in the longitudinal direction of the sealing end surface, in particular, the portion on the sealing end surface 5 side is deformed so as to fall toward the central axis Z side. When such deformation occurs, the diagonal portion 7 of the skirt portion 6 cannot be freely expanded and deformed, so that the diagonal portion 7 of the sealing end face 5 is partially expanded as shown in FIG. 7A. While protruding to the outer surface side, as shown in FIG. 7 (b), the diagonal portion 7 warps upward in the outer surface side in an inclined manner starting from the peripheral edge of the face portion 3 on the diagonal portion 7 side.

As a result, the diagonal portions 7 of the flat panel 1,
In particular, the strain caused by the deformation of each side portion 8 is concentrated near the sealing end surface 5 of the diagonal portion 7, and the thermal stress value acting on the sealing end surface 5 side portion of the diagonal portion 7 is significantly increased. On the other hand, in the case of a curved panel, due to the fact that the radius of curvature of the face portion is small, the face portion also undergoes thermal expansion in the direction along the central axis. Since the influence of thermal expansion on each side portion is reduced, the concentration of thermal stress on the diagonal portion as described above is alleviated. Therefore, as the radius of curvature of the outer surface of the face portion of the panel becomes larger and becomes flatter, the thermal expansion in the outer peripheral direction of the face portion due to the structure increases, and the vicinity of the sealing end surface 5 of the diagonal portion 7 is increased. The thermal stress value generated in the

Here, the mechanism by which the above-mentioned triangular cracks occur in the flat panel 1 will be described with reference to FIG.
Note that, in FIG. 8, the solid line arrow indicates the stress acting on the outer surface of the skirt portion 6, and the dotted line arrow indicates the stress acting on the inner surface of the skirt portion 6. Further, arrows pointing in opposite directions indicate tensile stress, and arrows pointing in directions approaching each other indicate compressive stress. Furthermore, the arrow indicated by the chain line indicates the direction of crack propagation.

As shown in the figure, in the temperature rising process of the flat panel 1, due to the deformation due to the above-mentioned thermal expansion, a predetermined position on the outer surface of the diagonal portion 7 from the sealing end surface 5 to the face portion 3 side. Tensile stress 1a is generated in a region (a position slightly closer to the sealing end face 5 side than the mold match line 9), and thermal stress concentration occurs in this region. Under such a stress-generating condition, if a defect such as a minute scratch exists in the vicinity of the sealing end surface 5 of the diagonal part 7, a crack is generated starting from this minute defect part. Since this crack propagates in a direction substantially orthogonal to the tensile stress 1a, a crack generated in the vicinity of the sealing end surface 5 of the diagonal portion 7 first shows the sealing end surface 5 as shown by an arrow 2a. Direction orthogonal to (tube axis Z
Parallel to the direction).

In this case, in the portion of the diagonal portion 7 slightly on the sealing end face 5 side from the mold match line 9,
While the compressive stress 3a is generated, the tensile stress 4a is generated on the line extending from the vicinity of this portion toward the sealing end surface 5 of each side portion 8 on both sides thereof in an inclined shape. For this reason, the crack that has propagated along the diagonal portion 7 along the above-mentioned arrow 2a is branched and changed in direction by the tensile stress 4a with the position slightly in front of the mold match line 9 as the apex, and turns from the apex to a fan-shaped arrow 5a. 5a to reach the sealing end surface 5. As a result, the sealing end surface 5 around the diagonal portion 7
The region including is broken so as to be peeled in a triangular pyramid shape, and the above-mentioned triangular crack is generated.

The occurrence of damage such as triangular cracks during the heat treatment is caused by defects such as minute scratches existing in the diagonal portion 7 of the sealing end face 5, as described above, and is flat. Since this causes fatal damage to the production of the panel 1 and hence the glass bulb for the cathode ray tube, in view of the current situation where the flat panel 1 is being produced in place of the curved panel, this kind of problem is very important. .

The present invention has been made in view of the above circumstances, and prevents the glass panel for a cathode ray tube having a flattened face portion from being damaged due to heat treatment, such as triangular cracking. A technical issue is to provide a high-quality glass panel having excellent properties.

[0019]

In order to solve the above problems, the inventors of the present invention have made diligent efforts, and as a result, in the temperature rising process in the process of sealing the glass panel for the cathode ray tube and the funnel, the sealing end face of the panel is Thermal stress concentration occurs on the outer side of the diagonal part, and damage such as triangular cracking due to the heat treatment described above occurs especially on the outer side of the diagonal part on the sealing end face of the panel. Recognizing or confirming that the micro scratches and the like are the starting point, the following technical means have been devised based on this.

That is, the first for solving the above problems
The technical means is a substantially rectangular face portion having an effective screen in which the radius of curvature of the outer surface on the diagonal axis is set to 10000 mm or more, and each side portion connected to the peripheral edge of the face portion through a blend R portion. And a skirt portion having a substantially rectangular sealing end surface at the opening end, in a glass panel for a cathode ray tube, an inclined chamfered portion at least outside a predetermined region including a diagonal axis on the sealing end surface of the skirt portion. Is formed.

Here, the first technical means has heretofore been a glass panel for a cathode ray tube in which no inclined chamfer is formed over the entire circumference of the sealing end surface, and the entire circumference of the sealing end surface. For example, it is a measure taken by paying attention to the existence of a glass panel for a cathode ray tube in which a minute R chamfered portion is formed, and is therefore applied to these panels. Then, "the inclined chamfer is formed at least on the outer side of the predetermined region including the diagonal axis".
Means that an inclined chamfered portion may be formed on the inner side of the predetermined region, and the "predetermined region" does not include a region over the entire circumference, but a region over the entire circumference. Part of the area. Further, the “inclined chamfer” means a chamfer formed of an inclined surface.

According to this structure, the sealing end surface of the glass panel for a cathode ray tube is fixed to another member in the process of fixing the glass panel on a predetermined table when polishing the surface of the glass panel or in various carrying processes of the panel. Even if it comes into contact with or slides on the sealing end face, an inclined chamfer is formed at least on the outer side of the predetermined region including the diagonal axis of the sealing end face. Mainly contact or slide with the other member, so that contact or sliding does not easily occur between the inclined chamfered portion, that is, the outer portion of the diagonal portion and the other member. As a result, the probability of occurrence of minute scratches or the like on the outer side of the diagonal portion of the sealing end surface of the panel due to the contact or sliding is significantly reduced. As a result, in the temperature rising process and the like when sealing the panel and the funnel using the frit glass, as described above, such as triangular cracks that start from the minute scratches existing particularly on the outer side of the diagonal part. The occurrence of damage is suppressed in advance.

A second technical means for solving the above problem is that the outer surface has a radius of curvature of 10 on the diagonal axis.
A skirt portion having a substantially rectangular face portion having an effective screen set to 000 mm or more and side portions connected to the periphery of the face portion through a blend R portion and having a substantially rectangular sealing end surface at the opening end. In a glass panel for a cathode ray tube comprising and, an inclined chamfered portion is formed on at least an outer portion of the entire circumference of the sealing end surface of the skirt portion, and the surface width of the inclined chamfered portion in a predetermined region including a diagonal axis is It is characterized in that the width is made wider than the inclined chamfered portion of the region.

With such a structure, the probability of occurrence of minute scratches or the like on the outer side of the diagonal part of the sealing end face of the panel is greatly reduced, similarly to the above-mentioned first technical means. Occurrence of damage such as triangular cracks originating from scratches is suppressed in advance. Further, in addition to this, it is possible to surely avoid chipping of the outer side portion over the entire circumference of the sealing end surface when an impact force or the like acts on the panel.

In the above structure, it is preferable that the inclined chamfered portion in the predetermined region including the diagonal axis is formed only in the diagonal portion of the sealing end surface and in the vicinity thereof. If you do this,
To reduce the thermal stress concentrated in the diagonal part of the sealing end face due to the thermal expansion deformation of the panel while dispersing it to the central part of the longitudinal direction of the sealing end face of each side away from the diagonal part. Therefore, for example, even when the panel is enlarged, it is possible to reliably suppress the occurrence of damage such as the above-described triangular crack.

Specifically, the inclined chamfered portion in a predetermined area including the diagonal axis is 5 mm or more from the diagonal axis of the sealing end surface toward the central portion side in the longitudinal direction of the sealing end surface of each side portion. It is preferable that it is formed in a range of 100 mm or less. That is, the dimension of this inclined chamfer is 5 m.
If it is less than m, the area where the occurrence of minute scratches can be suppressed becomes excessively narrow, and the occurrence of damage such as triangular cracks cannot be avoided with certainty. In particular, by enlarging the panel, the thickness of the entire panel is increased. When the thermal expansion deformation increases over time and the thermal expansion deformation becomes remarkable, the effect of forming the inclined chamfered portion sufficient to suppress the generation of thermal stress cannot be obtained. On the other hand, if the dimension of the inclined chamfer exceeds 100 mm, frit glass for sealing the panel and the funnel cannot be formed well, and the inside of the frit glass is made to have a high vacuum after sealing the both. At that time, the probability of damage due to defective frit glass increases, and as described above, the thermal stress concentrated in the diagonal part of the sealing end face is dispersed in the direction away from the diagonal part.・ It is not preferable for reducing the amount. Therefore, these problems can be avoided by setting the formation area of the inclined chamfered portion to the above-mentioned setting range.
The above-mentioned "center portion in the longitudinal direction of the sealing end surface of each side portion" means the central portion in the longitudinal direction of the sealing end surface of each side portion (hereinafter the same).

In the above construction, the surface width of the inclined chamfer in the predetermined region including the diagonal axis is 0.5 mm or more and 4.0.
The angle of inclination is preferably 30 mm or more and 60 ° or less, with respect to the sealing end surface. That is, as shown in FIG. 9 (a), when the surface width of the inclined chamfered portion 10 is less than 0.5 mm, the sealing end surface 5 of the panel 1 has a so-called angled shape in which the inclined chamfered portion is not substantially formed. As a result, the effect of suppressing the occurrence of minute scratches or the like on the diagonal part of the sealing end face cannot be sufficiently obtained during the manufacturing process of the panel and the transportation as described above. On the other hand, as shown in FIG. 9B, when the surface width of the inclined chamfered portion 10 exceeds 4 mm, the inclined chamfered portion 1
Since it is impossible to completely cover 0 with the frit glass 11, the surface of the frit glass 11 has an inclined chamfered portion 10.
With a small angle (for example, less than 100 °) to the panel 1 and the funnel 2 due to this.
When a high vacuum is applied to the inside of the glass bulb formed by sealing 0 and 0, damage may occur. Further, as shown in FIG. 9 (c), when the inclination angle of the inclined chamfered portion 10 with respect to the sealing end surface 5 (a surface perpendicular to the tube axis) is less than 30 °, a so-called angular standing state occurs and the above-mentioned diagram Similar to the aspect shown in FIG. 9 (a), it becomes impossible to obtain a sufficient effect of suppressing the occurrence of minute scratches and the like. On the other hand, as shown in FIG. 9 (d), when the inclination angle exceeds 60 °, the inclined chamfered portion 10 cannot be completely covered with the frit glass 11 and the above-described FIG. 9 (b) is obtained. When the inside of the glass bulb is set to a high vacuum in the same manner as in the embodiment shown, there is a risk of damage. Therefore, if the surface width and the inclination angle of the inclined chamfered portion are set within the above-mentioned set ranges, these problems can be avoided. In addition, here, the surface width of the inclined chamfer is set to 0.
Although it is set to 5 mm or more, for the same reason as this case,
More preferably 1.5 mm or more, 2.0 mm
The above is more preferable.

Further, in the above structure, the inclined chamfered portion in the predetermined region including the diagonal axis has a surface width from the diagonal axis side of the sealing end surface toward the central portion side in the longitudinal direction of the sealing end surface of each side portion. It is preferable to include a taper portion for gradually tapering.
With such a configuration, a sharp change in shape does not occur despite the formation of the inclined chamfered portion in a predetermined region of the sealing end surface, and the surface width gradually decreases so that the inclined chamfered portion at the sealing end surface is gradually reduced. Since it reaches the non-formation area, the molten glass is smoothly filled in the press mold during the molding of the panel without being disturbed, and molding defects such as wrinkles and cracks in the wall thickness changing portion Occurrence can be suppressed.

Further, in the above structure, it is preferable that the inclined chamfered portion in the predetermined region including the diagonal axis is formed so that the surface width becomes maximum on the diagonal axis. here,
"Maximum surface width on the diagonal axis" means not only that the surface width gradually increases toward the diagonal axis to maximize the surface width on the diagonal axis, but also that a predetermined value including the diagonal axis is included. This is a concept that includes maximizing the surface width in the range. According to this structure, since the surface width of the portion where the occurrence of defects such as micro scratches should be most suppressed is maximized, the occurrence of micro scratches and the like can be appropriately suppressed with high reliability, and leaning can be performed efficiently without waste. Since the chamfered portion can be formed, it is possible to further enhance the effect of suppressing damage at the time of temperature rise.

Further, in the above constitution, it is preferable that the inclined chamfered portion is formed during press molding. That is, the inclined chamfered portion can be formed by polishing, but with such a method,
This is not preferable because it causes a situation in which minute scratches due to polishing eventually remain, which causes damage such as the above-mentioned triangular crack. On the other hand, a molding surface corresponding to the inclined chamfer is formed on the molding surface of the mold used for press molding of the panel, and the inclined chamfer is formed by press molding using this. Thus, it is possible to avoid the occurrence of minute scratches on the inclined chamfered portion.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a glass panel for a cathode ray tube according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view of an essential part showing a periphery of a diagonal portion of the panel, and FIG. 3 is a diagonal portion of the panel. FIG. 4 is a schematic plan view showing the periphery, and FIG. 4 is a vertical sectional front view in which a diagonal portion of the panel is cut along a diagonal axis. In the following description, the same components as those described in the section of the above-mentioned conventional technique are designated by the same reference numerals, and the description or detailed description thereof will be omitted.

As shown in FIG. 1, a glass panel 1 for a color cathode ray tube (hereinafter, simply referred to as a panel) has a substantially rectangular face portion having an effective screen whose outer surface has a radius of curvature of 10000 mm or more on a diagonal axis X. 3 and the face portion 3
And a skirt portion 6 which is continuous with the blend R portion 4 through the blend R portion and has a sealing end surface 5 for joining with the funnel. The skirt portion 6 has four diagonal portions 7 which are interconnecting portions of the respective side portions 8 and are provided on the diagonal portion 7 of the sealing end surface 5, that is, on the outer side of a predetermined region including the diagonal axis X. An inclined chamfered portion 10 is formed in each case.

As shown in FIG. 2, the inclined chamfered portion 10 has a maximum surface width W in the inclined flat area 10a including the diagonal axis X, and the diagonal axis is formed at both ends of the flat area 10a. The longitudinal direction of the sealing end face of each side portion 8 from the X side (see FIG.
The surface width W is gradually reduced toward the central portion in the y-y direction). In this case, the gradual reduction unit 10
The b is formed as a curved surface or an inclined surface that is smoothly continuous with the flat area 10a, and is connected to the non-formed area of the inclined chamfered portion 10 in the sealing end surface 5 at an obtuse angle. Instead of this, the surface width W on the diagonal axis X is maximized, and the surface width W of the flat region 10a is not fixed and is symmetrical or substantially symmetrical on both sides of the diagonal axis X. Alternatively, a gradually decreasing portion having a curved surface and / or a flat surface, in which the surface width W gradually decreases toward the central portion side in the longitudinal direction of the sealing end surface of each side portion 8, may be formed.

As shown in FIG. 3, the regions where the inclined chamfered portions 10 are formed are respectively directed toward the central portion in the longitudinal direction of the sealing end face of the side portions 8 on both sides of the diagonal chamfer X as a reference. It is within a range of predetermined dimensions a and b. The predetermined dimensions a and b in the two directions are the same in the present embodiment,
The dimension value is set within a range of, for example, 5 mm or more and 100 mm or less.

As shown in FIG. 4, the inclined chamfered portion 10 has a surface width W of 0.5 mm or more and 4.0 mm or less, preferably 2.0 mm to 3.0 mm. The inclination angle θ with respect to (a plane orthogonal to the tube axis Z) is set to 30 ° or more and 60 ° or less, preferably 40 ° to 50 °.

As a method of forming the inclined chamfered portion 10 having the above-mentioned configuration on the panel 1, a convex portion having a shape corresponding to the inclined chamfered portion 10 is previously formed on the molding surface of the panel molding die. As an example, when the panel 1 is press-molded, the inclined chamfered portion 10 is formed on the panel 1.

On the other hand, the glass funnel for a cathode ray tube, which constitutes the glass bulb for a cathode ray tube by being sealed with the panel 1 described above, has a sealing end surface without an inclined chamfer (not shown). . Therefore, the glass bulb for a cathode ray tube has a panel 1 in which the inclined chamfered portion 10 is formed at a diagonal portion of the sealing end surface 5 and a funnel in which such an inclined chamfered portion is not formed in the sealing end surface.
It is manufactured by interposing frit glass between the both sealing end faces and sealing.

Instead of the above construction, the surface width is 0.3 mm or more and 1.5 mm or less, preferably 0.5 mm to 1.3 mm, and the inclination angle is 3 at the outer peripheral portion of the entire sealing end surface 5.
An inclined chamfer of 0 ° or more and 60 ° or less, preferably 40 ° to 50 ° is formed, and a face width W of 1.5 mm or more and 4.0 mm is formed outside the predetermined region including the diagonal axis X. Less than,
Preferably 2.0 mm to 3.0 mm, the inclination angle θ is 30
You may make it form the inclined chamfer of not less than 60 ° and not more than 60 °, preferably 40 ° to 50 °.

Further, in place of the above structure, the surface width W is 1.5 mm or more and 4.0 at the outer side portion of the entire circumference of the sealing end surface 5.
mm or less, preferably 2.0 mm to 3.0 mm, the inclination angle θ is 30 ° or more and 60 ° or less, preferably 40 ° to 5
The inclined chamfered portion of 0 ° may be formed, and the inclined chamfered portion having a different surface width may not be formed with respect to the predetermined region including the diagonal axis X described above.

[0040]

EXAMPLE As an example of the present invention, the aspect ratio is 4:
3. A panel having an outer diameter in the direction of the diagonal axis X of 724.8 mm and a radius of curvature of the outer surface of the face portion on the diagonal axis X of 100,000 mm was produced under the following conditions. That is, the surface width is 0.3 m on the outer side of the entire sealing end face of the panel.
An inclined chamfer having an inclination angle of 45 ° is formed at m, and the surface width W is 0 at the outer side in the range of 50 mm from the diagonal axis X toward the central portion side in the longitudinal direction of the sealing end surface of each side. .4 mm, 0.5 mm, 1.0 mm, 2.0 mm, and the inclination angle θ is 25 °, 30 °, 35 °, 4 respectively.
A total of 16 types of inclined chamfers having a 5 ° angle (see Table 1 below) were formed on the 16 panels described above. In this case, both ends of the inclined chamfered portion having a wide surface width W are connected to the inclined chamfered portion having a small surface width via the same gradually decreasing portion as described above.

After press-molding a total of 16 types of panels according to the above-mentioned embodiment, in a predetermined polishing step, each panel was placed on the table with the sealing end face contacting the table surface, The outer surface of the face portion of each panel was mirror-polished. After the completion of this polishing step, each panel was immersed in a 20% hydrofluoric acid aqueous solution for 30 seconds to emphasize the minute scratches generated on the sealing end face, and the state was visually observed. The reason for making such observations is that if there are extremely small scratches on the surface of the glass, the damage is enlarged and emphasized by eroding the glass with hydrogen fluoride in the hydrofluoric acid aqueous solution. , Because visual recognition is possible. The results are shown in Table 1 below.

[0042]

[Table 1]

As is clear from Table 1 above, the surface width W of each panel according to the embodiment of the present invention is 1.0.
mm, 2.0 mm and the inclination angle θ is 35
In the case of forming four types of inclined chamfered portions at 45 ° and 45 °, no extremely small scratches were observed in each inclined chamfered portion, and extremely favorable results were obtained. Among the panels according to the other examples, the surface width W was 0.5.
mm, 1.0 mm, 2.0 mm and the inclination angle θ is 3
A product having an inclined chamfer of 0 ° and a surface width W of 0.
Even in the case where the inclined chamfers having the inclination angles θ of 5 mm and 35 ° and 45 °, respectively, were formed, fine scratches on the inclined chamfers could hardly be confirmed, and favorable results were obtained. Further, each panel according to the examples other than these,
As indicated by the triangle mark in Table 1, some slight scratches can be confirmed on each inclined chamfered portion, but it cannot be said that the scratches cause damage such as triangular cracks. Therefore, good results were obtained also by this. .

Therefore, paying attention to the occurrence of minute scratches,
The surface width W of the inclined chamfer on the sealing end surface of the panel is
If the inclination angle θ is 0.4 mm or more and the inclination angle θ is 25 ° or more, a sufficient effect can be obtained, and it is more preferable that the surface width W is 0.5 mm or more and the inclination angle θ is 30 ° or more, The surface width W is 1.0 mm or more and the inclination angle θ is 35.
It was confirmed that it is more preferable if it is at least °.

Next, the aspect ratio is 4: 3 and the outer diameter in the diagonal axis direction is 724 corresponding to the panel according to the above-mentioned embodiment.
mm, the width of the sealing end face is the same as the above panel, and the deflection angle is 12
A total of 16 funnels for 0 ° cathode ray tubes were produced. Then, these funnels were installed on a predetermined jig, and frit glass (Asahi Glass Co., Ltd.) was placed on the sealing end surface of the funnel.
Manufactured; ASF-1307B) was dispersed in an organic vehicle to apply a slurry, and after drying, each panel was placed on the sealing end surface. After this, these are the highest temperature 4
The glass bulb for a cathode ray tube was obtained by sealing each panel and each funnel through a heat treatment furnace having a predetermined temperature gradient maintained at 50 ° C. for 20 minutes. Next, the vicinity of the inclined chamfer having a wide surface width W of each panel in these glass bulbs was observed. Then, the part where the frit shape was not good was cut, and the frit shape was observed in more detail. The results are shown in Table 2 below. In this case, the surface width W of the panel according to the example is 2.
0 mm, 3.0 mm, 3.8 mm, and 4.5 mm, and the inclination angle θ is 45 °, 55 °, 60 °, and 65 °, respectively.
A total of 16 types of inclined chamfered parts were used. The formation region of these inclined chamfers and the inclined chamfers of the other regions are the same as those described above.

[0046]

[Table 2]

As is clear from Table 2 above, among the glass bulbs for cathode ray tubes using each panel according to the embodiment of the present invention, the surface width W of each panel is 2.0 mm and 3.
The four types of inclined chamfers having a tilt angle θ of 0 ° and 45 ° and 55 °, respectively, had a very good frit shape, and in addition to this, the surface width W was 2.0 mm each. , 3.0 mm and 3.8 mm with an inclined chamfer having an inclination angle θ of 65 °, and a total having a surface width W of 3.8 mm and an inclination angle θ of 45 ° and 55 °, respectively. The frit shape was also good for the five types of inclined chamfers.
Further, in the glass bulb for a cathode ray tube using each panel according to the examples other than these, as shown in Table 2 by Δ, each frit shape has some unfavorable portions, but it is damaged due to defective frit glass. It was not enough to cause the above, and it could withstand its use sufficiently.

Therefore, focusing on the frit shape of the glass bulb for a cathode ray tube, if the surface width W of the inclined chamfered portion at the sealing end surface of the panel is 4.5 mm or less and the inclination angle θ is 65 ° or less. A sufficient effect can be obtained, the surface width W is 3.8 mm or less, and the inclination angle θ is 60.
It has been confirmed that it is more preferable if the angle is less than or equal to 0 °, and further preferable if the surface width W is less than or equal to 3.0 mm and the inclination angle θ is less than or equal to 55 °.

[0049]

As described above, according to the present invention, a skirt is provided in a glass panel for a cathode ray tube having a substantially rectangular face portion forming an effective screen having a radius of curvature of an outer surface of 10000 mm or more on a diagonal axis. Since the inclined chamfered portion is formed at least on the outer side of the predetermined region including the diagonal axis on the sealing end surface of the part, the sealing end surface and other members come into contact or slide in various steps after the panel is molded. Even in this case, the contact or sliding of the outer side of the diagonal part of the sealing end face is appropriately avoided. As a result, it is possible to suppress the generation of minute scratches or the like on the outer side of the diagonal part of the sealing end face of the panel, and to start the small scratches or the like on the diagonal side of the sealing end face when the panel is expanded and deformed by heat treatment. As a result, it becomes possible to prevent the occurrence of damage such as triangular cracks.

Further, according to the present invention, in a glass panel for a cathode ray tube having a substantially rectangular face portion forming an effective screen in which the radius of curvature of the outer surface on the diagonal axis is 10,000 mm or more, the skirt portion is sealed. The inclined chamfered portion is formed at least on the outer side of the entire circumference of the end face, and the surface width of the inclined chamfered portion of the predetermined region including the diagonal axis is made wider than the inclined chamfered portion of the other region. The occurrence of minute scratches or the like on the outer side of the diagonal part of the sealing end surface of the panel is suppressed, and the occurrence of damage such as triangular cracks originating from these minute scratches is suppressed, and the sealing end surface The probability of occurrence of chipping of the outer part over the entire circumference is greatly reduced.

The inclined chamfered portion in the predetermined region including the diagonal axis is 5 mm or more and 100 m from the diagonal axis of the sealing end surface toward the central portion in the longitudinal direction of the sealing end surface of each side.
By forming it in the range of m or less, the effect of suppressing the generation of minute scratches and the like can be sufficiently obtained, and the thermal stress from the diagonal portion can be appropriately dispersed and reduced.

Further, the surface width of the inclined chamfered portion in a predetermined region including the diagonal axis is set to 0.5 mm or more and 4.0 mm or less,
Moreover, by setting the inclination angle of the inclined chamfered portion with respect to the sealing end surface to be 30 ° or more and 60 ° or less, a so-called angled state occurs, and the inclined chamfered portion cannot be completely covered with frit glass. It is possible to avoid such problems as described above, to reliably obtain the effect of suppressing the generation of minute scratches, etc., and to appropriately prevent damage to the glass bulb due to defective sealing of the frit glass.

Further, the inclined chamfered portion of the predetermined region including the diagonal axis has a gradually decreasing portion in which the surface width gradually decreases from the diagonal axis side of the sealing end surface toward the central portion in the longitudinal direction of the sealing end surface of each side. By including the inclined chamfered portion, a rapid change in wall thickness does not occur despite the formation of the inclined chamfered portion, and the inclined chamfered portion gradually decreases to reach the region where the inclined chamfered portion of the sealing end face is not formed. Therefore, the molten glass is smoothly filled in the press mold during the molding of the panel, and it is possible to prevent the occurrence of molding defects such as wrinkles and cracks in the shape change portion.

Further, the inclined chamfered portion in the predetermined area including the diagonal axis is formed so that the surface width becomes maximum on the diagonal axis, so that minute scratches and the like are appropriately generated with high reliability. Can be suppressed, and the effect of suppressing damage such as triangular cracks can be further enhanced.

Further, by forming the inclined chamfered portion at the time of press molding, fatal problems such as occurrence of minute scratches at the time of processing such as in the case of polishing processing can be avoided.

[Brief description of drawings]

FIG. 1 is a perspective view showing a glass panel for a cathode ray tube according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a main part of a glass panel for a cathode ray tube according to an embodiment of the present invention.

FIG. 3 is a schematic plan view showing a main part of a glass panel for a cathode ray tube according to an embodiment of the present invention.

FIG. 4 is an enlarged vertical sectional front view of an essential part of the glass panel for a cathode ray tube according to the embodiment of the present invention cut along a diagonal axis.

FIG. 5 is a perspective view showing a conventional glass panel for a cathode ray tube.

6 (a) and 6 (b) are schematic perspective views each schematically showing a glass panel for a cathode ray tube showing conventional problems.

FIG. 7 (a) is a schematic plan view of an essential part of a glass panel for a cathode ray tube showing a conventional problem, and FIG. 7 (b) is a schematic vertical section of an essential part of a glass panel for a cathode ray tube showing a conventional problem. It is a front view.

FIG. 8 is an enlarged schematic front view of a main part of a glass panel for a cathode ray tube showing a conventional problem.

9 (a), (b), (c), and (d) are enlarged schematic front views of a glass bulb for a cathode ray tube showing conventional problems.

[Explanation of symbols]

1 panel (glass panel for cathode ray tube) 3 face part 4 Blend R part 5 Sealed end face 6 Skirt 7 diagonal 8 sides 10 Inclined chamfer 10b taper X diagonal axis

Claims (7)

[Claims] 1. The radius of curvature of the outer surface on the diagonal axis is 1
A skirt portion having a substantially rectangular face portion having an effective screen set to 0000 mm or more, and each side portion connected to the periphery of the face portion through a blend R portion and having a substantially rectangular sealing end surface at the opening end. A glass panel for a cathode ray tube, comprising: a glass panel for a cathode ray tube, wherein an inclined chamfered portion is formed at least on an outer side of a predetermined region including a diagonal axis on the sealing end surface of the skirt portion. 2. The radius of curvature of the outer surface on the diagonal axis is 1
A skirt portion having a substantially rectangular face portion having an effective screen set to 0000 mm or more, and each side portion connected to the periphery of the face portion through a blend R portion and having a substantially rectangular sealing end surface at the opening end. In a glass panel for a cathode ray tube having and, forming an inclined chamfered portion on at least an outer portion of the entire circumference of the sealing end surface of the skirt portion, the surface width of the inclined chamfered portion of a predetermined region including a diagonal axis, A glass panel for a cathode ray tube, wherein the glass panel is wider than the inclined chamfered portion of the region. 3. The inclined chamfered portion in a predetermined region including the diagonal axis is 5 mm or more from the diagonal axis of the sealing end surface toward the central portion side in the longitudinal direction of the sealing end surface of each side portion and 100
The glass panel for a cathode ray tube according to claim 1, wherein the glass panel is formed in a range of not more than mm. 4. The surface width of the inclined chamfer in a predetermined region including the diagonal axis is 0.5 mm or more and 4.0 mm or less, and the inclination angle of the inclined chamfer with respect to the sealing end surface is 30 °.
It is 60 degrees or less above, and Claims 1-3 characterized by the above-mentioned.
A glass panel for a cathode ray tube according to any one of 1. 5. The inclined chamfered portion in a predetermined region including the diagonal axis gradually decreases in width from the diagonal axis side of the sealing end surface toward the central portion of the longitudinal direction of the sealing end surface of each side portion. The glass panel for a cathode ray tube according to any one of claims 1 to 4, further comprising a portion. 6. The inclined chamfered portion in a predetermined region including the diagonal axis is formed so that the surface width becomes maximum on the diagonal axis. The glass panel for a cathode ray tube described. 7. The glass panel for a cathode ray tube according to claim 1, wherein the inclined chamfered portion is formed during press molding.