JP2002358910A - Glass panel for cathode-ray tube and glass bulb for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat resistant strength of a glass panel and a glass bulb by preventing generation of damage such as triangular cracking at a glass panel for a cathode-ray tube having a flattened face part. SOLUTION: With the panel for the cathode-ray tube provided with a face part with curvature radius on the outer surface on the diagonal axis X not less than 10,000 mm, a thick part 20 is formed in the region including at least a sealing end face 5 or the vicinity at a diagonal part 7 of a skirt part 6 and in the direction parallel to the tube axis Z. The thick part 20 is preferably formed at thermal stress centering region at thermal treatment.

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 a glass bulb for a cathode ray tube, and more particularly to a technique for improving the heat resistance of these glass articles.

[0002]

2. Description of the Related Art As is well known, a cathode ray tube includes, as main glass parts, a panel 1 on which an image is projected and a funnel 2 having a funnel shape as shown in FIGS. 7 (a) and 7 (b). . The panel 1 includes a substantially rectangular face portion 3 having an effective screen for displaying an image, and the face portion 3.
Through the blend R part 4 and the funnel 2
And a skirt portion 6 having a sealing end surface 5 to be joined to the skirt portion 6. The skirt portion 6 has each side portion 8 between the four diagonal portions 7. On the other hand, the funnel 2 includes a neck portion 10 having a circular small-diameter side opening end into which an electron gun is inserted, and a funnel-shaped body portion 11 which gradually expands from a circular shape to a substantially rectangular shape. . The body portion 11 has a substantially rectangular sealing end surface 12 at the large-diameter side opening end, and includes each side wall constituting portion 14 between the four diagonal portions 13 on the sealing end surface 12 side. .

In the process of manufacturing a color cathode ray tube, the sealing end face 5 of the panel 1 and the sealing end face 12 of the funnel 2 are sealed with a solder glass (hereinafter referred to as frit glass) interposed therebetween. Thus, a glass bulb for a cathode ray tube is manufactured. The glass bulb for a cathode ray tube is used as an envelope of the cathode ray tube in a state where the inside thereof is evacuated to a vacuum, and a stress due to a difference in pressure between inside and outside is applied to the wall thereof.

For this reason, a conventional glass bulb for a cathode ray tube is used.
Maintain the appropriate mechanical strength and
Thickness of the panel 1, especially the
Generally, the thickness of the base portion 3 is increased. Change
8, the sealing end face 5 of the panel 1 is
Thickness t of each side 8 (long side 8 and short side 8)_xAnd each pair
Wall thickness t of corner 7_yHas a uniform thickness distribution over the entire circumference
It is customary. Sealing of the funnel 2
Similarly, the end face 12 has a thickness t of each side wall component 14. _xAnd each
Thickness t of diagonal part 13_yHas a uniform thickness distribution over the entire circumference
Have.

[0005]

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 section) having a face portion 3 that forms an effective screen of not less than 1 mm has been manufactured. When this flat panel 1 becomes a component of the glass bulb for a cathode ray tube described above,
The stress due to the difference between the inside and outside air pressures applied to the face portion 3 is significantly larger than that of a curved panel (a panel which occupied the mainstream before the flat panel 1 became popular). For this reason, the face portion 3 of the flat panel 1
Is generally set to be thicker than at least the entire sealing end face 5 formed at the opening end of each side portion 8 and the diagonal portion 7 and the vicinity thereof.

In this case, in the step of sealing the flat panel 1 and the funnel 2 for manufacturing a glass bulb for a cathode ray tube, a frit is provided between the sealing end face 5 of the flat panel 1 and the sealing end face 12 of the funnel 2. By exposing the glass to the internal atmosphere of a heat treatment furnace having a maximum temperature of about 450 ° C., each of the sealing end faces 5 and 12 reacts with the frit glass to generate a chemical bond. .

In the heating process in the sealing step, the face portion 3 of the flat panel 1 is substantially rectangular and the outer surface thereof is flattened. In this case, different thermal expansion deformation occurs, and thermal stress concentration occurs on the sealing end face 5 of the flat panel 1 and on the outer surface of the diagonal portion 7 in the vicinity thereof. Then, a crack originating from the outer surface of the diagonal portion is generated with the concentration of the thermal stress, and the crack propagates in the process of increasing the temperature. A break occurs in a triangular pyramid shape over the portion 8, and a phenomenon called a so-called triangular crack occurs.

This triangular crack is a unique problem that occurs in the flat panel 1 and can be said to be a phenomenon that could not occur in a curved panel. That is, as described above, the flat panel 1 has a face portion 3 whose outer surface has a radius of curvature of 10000 mm or more on the diagonal axis X, and a sealing end surface 5 which is an opening end from a peripheral edge thereof through a blend R portion 4. And a skirt portion 6 leading to the end. Therefore, the expansion accompanying the application of heat to the flat panel 1 causes
A structural deformation as shown in FIGS. 9 and 10 occurs. FIGS. 9A and 9B show one quadrant obtained by cutting the flat panel 1 along the long axis A and the short axis B (see FIG. 7), as heat is applied to the flat panel 1. This schematically illustrates the mode of thermal expansion deformation that occurs, and the arrows in the figure show the direction of deformation due to thermal expansion. FIG. 10A is a schematic view of the periphery of the diagonal portion 7 of the sealing end face 5 viewed from a direction perpendicular to the face surface, and a dotted line in the figure schematically shows the shape during thermal expansion deformation. FIG. 10B shows a skirt 6
3 is a schematic vertical cross-sectional view taken along a diagonal axis X of the periphery of the diagonal part 7 of FIG.

[0009] Specifically, in the heating process in the heat treatment process for sealing with the funnel 2, as shown in FIG. 9 (a), the blending starts from the center axis Z (tube axis) of the face portion 3. 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 8 of the skirt portion 6 is an open end, and therefore, FIG.
As shown in (b), the center of each side 8 in the longitudinal direction of the sealing end face, in particular, the sealing end face 5 side portion is deformed so as to fall down to the center axis Z side. When such deformation occurs,
Since the diagonal portion 7 of the skirt portion 6 cannot be freely expanded and deformed, the diagonal portion 7 of the sealing end face 5 as shown in FIG.
Partially protrude to the outer surface side, and as shown in FIG. 10 (b), the diagonal portion 7 rises in an inclined manner upward on the outer surface side from the periphery of the diagonal portion 7 side of the face portion 3 as a starting point.

As a result, the diagonal portions 7 of the flat panel 1
In particular, the strain due to 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 small radius of curvature of the face portion, the face portion also undergoes thermal expansion in the direction along the central axis. Since the influence of thermal expansion on each side is reduced, the concentration of thermal stress at the diagonal portion as described above is reduced. Therefore, as the curvature radius of the outer surface of the face portion of the panel increases and becomes flat, the thermal expansion in the outer peripheral direction of the face portion due to the structure increases, and the diagonal portion 7 near the sealing end face 5 The thermal stress value generated at the time increases.

Here, the mechanism of the above-described triangular cracking in the flat panel 1 will be described with reference to FIG. In FIG. 11, the solid arrow indicates the stress acting on the outer surface of the skirt 6, and the dotted arrow indicates the stress on the skirt 6.
Shows the stress acting on the inner surface of Also, arrows pointing in opposite directions indicate tensile stress, and arrows pointing in an approaching direction indicate compressive stress. Furthermore, the arrow shown by the chain line shows the direction of crack propagation.

As shown in FIG. 1, in the process of raising the temperature of the flat panel 1, a predetermined position on the outer surface of the diagonal portion 7 from the sealing end face 5 to the face portion 3 due to the above-mentioned deformation due to thermal expansion. Tensile stress 1a is generated in a region (a position slightly closer to sealing end surface 5 than mold match line 16), and thermal stress concentration occurs in this region. Under such stress generation conditions, if a defect such as a minute scratch exists near the sealing end face 5 of the diagonal portion 7, a crack starts from the minute defect portion. This crack has a tensile stress of 1a.
The cracks generated in the vicinity of the sealing end face 5 of the diagonal portion 7 first develop in the direction orthogonal to the sealing end face 5 (the pipe axis) as shown by the arrow 2a. (Parallel to Z).

In this case, a compressive stress 3a is generated at a portion of the diagonal portion 7 slightly closer to the sealing end face 5 than the mold match line 16, whereas a portion near this portion and each of the two sides on the opposite side are formed. A tensile stress 4a is generated on a line extending in an inclined manner toward the sealing end face 5 of the side portion 8. For this reason, the crack which has developed in the diagonal portion 7 along the above-mentioned arrow 2a branches and changes its direction by the tensile stress 4a with the vertex slightly in front of the mold match line 16 and changes its direction. , 5a to reach the sealing end face 5. As a result, the area including the sealing end face 5 around the diagonal portion 7 is broken so as to be peeled in a triangular pyramid shape, and the above-described triangular crack occurs.

The occurrence of breakage during such heat treatment causes fatal damage to the production of the flat panel 1 and thus the glass bulb for the cathode ray tube, and the production of the flat panel 1 has been increased in place of the curved panel. In light of the current situation, this type of problem is of great importance.

The present invention has been made in view of the above circumstances, and prevents a glass panel for a cathode ray tube having a flattened face portion from being damaged due to heat treatment, such as triangular cracks. It is a technical object to improve the heat resistance of a glass panel and a glass bulb.

[0016]

SUMMARY OF THE INVENTION In order to achieve the above technical object, the present invention provides a substantially rectangular face portion forming an effective screen having a radius of curvature of an outer surface on a diagonal axis of 10,000 mm or more. A skirt portion having each side portion connected to the periphery of the face portion via the blend R portion and having a substantially rectangular sealing end surface at an open end, wherein a diagonal portion of the skirt portion is provided. And a thicker portion that is thicker in a region including at least the sealing end surface in the direction parallel to the tube axis or in the vicinity thereof than a portion corresponding to the region in the center portion in the longitudinal direction of the sealing end surface of each side. Is formed. here,
The “tube axis parallel direction” means a direction parallel to the tube axis (the central axis of the panel). Further, “in the vicinity thereof” means a position existing within a range from the sealing end face to the face portion side by, for example, 5 mm.

According to such a configuration, the diagonal portion of the cathode ray tube panel having the face portion whose outer surface is flattened has a region including at least the sealing end face in the tube axis parallel direction or the tube axis parallel direction. The thick portion is formed in a region including at least the vicinity of the sealing end face in the direction. This thick portion is a portion corresponding to the above-mentioned region in the central portion in the longitudinal direction of the sealing end face of each side, that is, the central portion with respect to the longitudinal direction of the sealing end face of each side and in the direction parallel to the pipe axis. On the other hand, it is thicker than a portion corresponding to the region. Therefore, the glass thickness of the skirt portion from the mold match line of the panel to the sealing end surface can be made thicker in a predetermined region of the diagonal portion and relatively thin in a region other than the predetermined region. By increasing the thickness of the sealing end surface at the diagonal portion or the vicinity thereof, thermal deformation of the skirt portion can be suppressed, and mechanical strength against thermal stress generated by the thermal deformation can be increased. As a result, during the heating process when the panel and the funnel are sealed with frit glass through the heat treatment furnace, triangular cracking occurs due to thermal stress concentration generated around the sealing end face at the diagonal portion due to thermal expansion deformation of the panel. Such a problem that breakage occurs is effectively avoided.

From such a viewpoint, it is preferable that the thick portion is formed in a thermal stress concentration region at the time of heat treatment. Here, “Thermal stress concentration region during heat treatment”
The term means a region where thermal stress is concentrated and acts when the thick portion is formed and / or when the thick portion is not formed.

The thickness t ₁ of the thick portion on the diagonal axis is 1.05 ≦ the thickness t ₀ of the corresponding portion in the longitudinal center of the sealing end face of each side. t ₁ / t
It is preferable to have a relationship of ₀ ≦ 1.50. Here, the “corresponding portion” means a portion corresponding to the region where the thick portion is formed in the direction parallel to the tube axis. In this case, the thickness t ₁ on the diagonal axis is, for example, the maximum thickness of the thick portion.

In this case, in the above condition setting, t ₁
The reason for setting / t ₀ ≦ 1.50 is as follows. That is, if the glass thickness of the diagonal part is increased, the thermal stress value generated on the sealing end face of the diagonal part is reduced, but the thickness of the sealing end face of the diagonal part or the vicinity thereof is reduced by each side. If the thickness of the sealing end face in the central portion in the longitudinal direction of the portion is longer than the thickness at or near the sealing end face, the change in the thickness from the diagonal portion to the center portion of each side becomes large. By the way, when press-molding this type of panel with a pressing die, the portion where the time required to completely fill the molten glass in the molding die is the longest distance from the panel center axis (tube axis). In the case of the corner portion, when the diagonal portion is thickened as described above, it is necessary to increase the press time in the molding die by an amount corresponding to the thickening. As described above, when the total time required for the press molding of the panel increases, a portion where the time required for filling the molten glass becomes the shortest, that is, a pair of sides (long sides) having the shortest distance from the panel center axis. The center of the sealing end face in the longitudinal direction of the part (2) has a long press-applying time from the beginning, but the press-applying time becomes longer by the increased amount. In addition, molding defects such as wrinkles and cracks occur near the sealing end face of the side (long side). Therefore,
The first reason for setting t ₁ / t ₀ ≦ 1.50 is to avoid occurrence of such molding defects. Also, as a result of forming an excessively thick portion at the diagonal portion, if the thickness of the diagonal portion near the sealing end face becomes thicker than the thickness of the blend R portion, the panel becomes Die removal after press molding becomes difficult. Therefore, the second reason for setting t ₁ / t ₀ ≦ 1.50 is to avoid such difficulties in die cutting.

On the other hand, in the above condition setting, 1.05
≦ t ₁ / t ₀ is set for the following reason. That is, in general, when an external force due to a mechanical or thermal uniform distribution load is applied to the surface of a sheet glass, a stress value Q caused thereby is roughly calculated by the following equation (1).

Q = βWa ² × (1 / t ² ) (1)

In the above equation (1), W is a uniformly distributed load, and t is
The thickness a is a short side of the quadrilateral, and β is a coefficient determined by b / a (long side / short side).

In this case, the cathode ray tube panel is a substantially rectangular plate.
Face part, and vertically from the periphery of the face part
A substantially rectangular shape composed of a bent plate-shaped skirt
Since it has a body-like box shape,
Is corrected by the factor β.
By using the above formula (1) as an index, approximation
can do. Therefore, it is clear from the above equation (1).
The stress value generated at the same position on the panel
Is approximately inversely proportional to the square of the wall thickness
Can be seen. Taking this into account, t₁/ T₀<
If it is 1.05, the diagonal part of the panel is thickened.
Also has the effect of increasing mechanical rigidity against thermal expansion deformation
It is extremely small and it is difficult to effectively suppress thermal stress concentration.
It will be difficult. Therefore, in the above condition setting, 1.05 ≦ t₁/
t₀The increase in mechanical rigidity against thermal expansion deformation
This is to ensure a sufficient effect. This thermal expansion deformation
In order to obtain a sufficient effect of increasing the mechanical rigidity,
The setting condition is 1.10 ≦ t ₁/ T₀≤ 1.50
Is more preferable.

In the above configuration, the thick portion is formed to have a uniform thickness t ₁ within a range of 5 mm or more and 80 mm or less from the diagonal axis toward the center in the longitudinal direction of the sealing end face of each side. It is preferred that

That is, it is preferable that the thick portion is not formed over the entire periphery of the skirt portion, but is formed only in a diagonal portion (and its peripheral portion). In the circumferential direction of the skirt portion, the thick portion is formed only in the diagonal portion (and the peripheral portion thereof), and in the direction parallel to the tube axis, only in the sealing end face or in the vicinity thereof. May be. Due to the formation of such a thick portion, the thermal stress concentrated on the sealing end face side of the diagonal portion during the temperature rising process when sealing the panel and the funnel is reduced to the diagonal portion (and its peripheral portion). ) Can be dispersed and reduced in the direction of each side away from the panel, and, for example, even when the panel is enlarged, the occurrence of the above-described damage can be reliably suppressed.

In this case, the reason why the thick portion is formed to have a uniform thickness t ₁ within a range of 80 mm or less is that thermal stress concentrated on the sealing end face side of the diagonal portion is reduced by the diagonal portion and the thermal stress. This is for dispersing and reducing in the direction of each side away from the vicinity, and for avoiding excessive weight increase of the panel due to the formation of the thick portion. On the other hand, the reason why the thick portion is formed to have a uniform thickness t ₁ in the range of 5 mm or more is that if the thickness is less than 5 mm, the thermal expansion deformation is remarkable as the panel size increases. This is because, in the case of, the effect of increasing the wall thickness sufficient to suppress the occurrence of thermal stress that increases on the sealing end face side of the diagonal portion cannot be obtained.

[0028] In the above configuration, the thick portion, it is preferable that the thickness t ₁ is reached the thick t ₀ gradually decreases towards the seal end faces a longitudinal center portion of the each side portion. In this case, the thick portion includes a narrow region including a portion on the diagonal axis, for example, a narrow region of less than 5 mm from the diagonal axis toward the center in the longitudinal direction of the sealing end face of each side portion with a thickness t _1. age,
The thickness t ₁ may be gradually reduced from the end of this narrow region, or a wide region of 5 mm or more and 80 mm or less from the diagonal axis toward the center in the longitudinal direction of the sealing end face of each side. The thickness t ₁ may be uniform, and the thickness t ₁ may be gradually reduced from the end of the wide area.

By adopting such a configuration, no sudden change in thickness occurs despite the formation of the thick portion, and the thickness gradually decreases from t ₁ to t ₀ , and the panel The filling of the molten glass in the press mold at the time of molding is smoothly performed without being hindered, and the occurrence of molding defects such as wrinkles and cracks in the thickness change portion can be prevented.

In the above structure, the thick portion can be made thicker by increasing the inner surface or the outer surface of the diagonal portion (and its peripheral portion) or both of the existing (conventional) panel. However, in the case where the outer shape of the existing panel is not changed, it is necessary to change the mounting parts and the mounting position when assembling the cathode ray tube having the panel as a component to the cabinet. Considering this, it is preferable to increase the thickness of the inner surface of the diagonal portion (and its peripheral portion) to form a thick portion.

Further, in the above configuration, the mold match line on the sealing end face side is formed such that the thickness gradually decreases from the mold match line at the diagonal portion (and the peripheral portion) of the skirt to the sealing end face. It is preferable to form a thick portion in a region that does not include. In this case, not only the increase in the weight of the panel due to the formation of the thick portion can be appropriately suppressed, but also the shape has a small thickness change from the mold match line side to the sealing end face, and there is a sharp thickness change. In this case, the mechanical strength of the diagonal portion (and its peripheral portion) can be effectively increased while avoiding an increase in thermal tensile stress generated on the inner surface of the peripheral edge of the face portion or the inner surface of the skirt portion.

The present invention also provides a sealing end face of a glass funnel for a cathode ray tube having a funnel-shaped body portion having a substantially rectangular sealing end face at a large diameter opening end, the diameter of which gradually increases from a small diameter opening end. And a sealing end face of the glass panel for a cathode ray tube, wherein the sealing end face of the glass funnel for a cathode ray tube or a form in the vicinity thereof is sealed with the sealing end face of the glass panel for a cathode ray tube. It is characterized in that it corresponds to the form of the end face or its vicinity.

That is, the thick portion is formed on the diagonal portion of the funnel on the side of the sealing end face and in a region including at least the sealing end face or its vicinity in the direction parallel to the tube axis.

More specifically, the thick portion of the funnel is
Each of the side wall components located between the diagonal portions of the funnel-shaped body portion is thicker than a portion corresponding to the region at the longitudinal center portion of the sealing end face.

The thickness t ₁ of the thick portion formed on the funnel on the diagonal axis is the thickness t ₁ of the corresponding portion at the longitudinal center of the sealing end face of each of the side wall constituting portions.
Against _0, it is preferable to have a relationship of _{1.05 ≦ t 1 / t 0 ≦} 1.50.

The thick part formed in the funnel has a uniform thickness t in the range of 5 mm to 80 mm from the diagonal axis toward the center in the longitudinal direction of the sealing end face of each side wall component. It is preferably formed in ₁ .

Further, in the thick portion formed in the funnel, the thickness t ₁ gradually decreases toward the center in the longitudinal direction of the sealing end face of each of the side wall constituting portions to reach the thickness t _0. Is preferred.

The thick portion of the funnel as described above does not need to be the same or substantially the same in the direction parallel to the tube axis as compared with the thick portion of the panel described above.
The form of the sealing end face of the funnel in the state where the thick portion is formed or its vicinity in the direction parallel to the tube axis must correspond to the form of the sealing end face of the panel or its vicinity in the direction parallel to the tube axis. is there.

According to the glass bulb for a cathode ray tube obtained by joining and welding a funnel having the above structure and the above-described panel, the sealing portion between the panel and the funnel, particularly, the sealing portion at the diagonal portion between the two. There is no danger of inferior shape of the joint due to mismatch, and the sealing strength between the panel and the funnel by frit glass can be increased.
In addition, there is no fear that the mechanical strength of the glass bulb for a cathode ray tube after sealing is lowered. In particular, even when the panel or funnel is enlarged, the strength of the glass bulb for a cathode ray tube is reduced due to poor sealing by frit glass,
In addition, problems such as damage caused by the sealing end face as a starting point can be avoided.

[0040]

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 a first embodiment of the present invention, FIG. 2 is a schematic enlarged plan view showing the periphery of a diagonal portion of the panel, and FIG. It is the longitudinal cross-sectional view which cut | disconnected the part along the diagonal axis. In the following description, the same components as those described in the section of the related art described above are denoted by the same reference numerals, and the description or the detailed description thereof will be omitted. Also, the reference numerals of the drawings used only for the description in the section of the related art are appropriately used.

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 provided with an effective screen having a radius of curvature of an outer surface of 10,000 mm or more on a diagonal axis X. 3 and the face portion 3
And a skirt 6 having a sealing end face 5 for joining to the funnel 2 through the blend R portion 4. Each of the four diagonal portions 7 of the skirt portion 6 forming an interconnecting portion of each side portion 8 is relatively thicker than the other portion of each side portion 8 (the central portion in the longitudinal direction of the sealing end face). The thick part 20 is integrally formed. In this case, the central portion in the longitudinal direction of the sealing end face of each side 8 is the longitudinal direction of the sealing end face for each side 8 (the ww direction shown in the figure).
And a region excluding the diagonal portion 7 of the skirt portion 6 and a region where the thick portion 20 is not formed.

As shown in FIG. 2, the thick portion 20 is formed so as to have a maximum thickness t ₁ on the diagonal axis X, and from the portion having the maximum thickness t ₁ to each side 8. The thickness gradually decreases toward the central portion in the longitudinal direction of the sealing end face, and the shape is such that the thickness t ₀ is the thickness of the central portion in the longitudinal direction of the sealing end face of each of the side portions 8. In the state where the thick portion 20 is formed at the diagonal portion 7, as shown in FIG. 3, the thickness gradually increases from the mold match line 16 having the maximum outer diameter to the sealing end face 5 (or its vicinity). It is shaped to be thinner.

In this case, the chain line shown in the figure shows the thickness distribution at the diagonal portion in the existing (conventional) panel.
Therefore, the thick portion 20 may be formed by increasing the thickness only on the inner surface side of the existing diagonal portion, or may be formed by increasing the thickness only on the outer surface side of the existing diagonal portion. Alternatively, it may be formed by increasing the thickness of both inner and outer surfaces as shown in FIG. The configuration shown in FIG.
From the sealing end face 5 in the direction parallel to the tube axis Z, for example, within a range from the sealing end face 5 to a distance of 5 mm from the sealing end face 5 to the face 3 side. The thick portion 20 may be formed from the position existing in the direction toward the face portion 3 from this position. Further, the end position of the thick portion 20 (increased portion) on the face portion 3 side may be a position corresponding to the inner surface 3x of the face portion 3 as shown in the drawing, but is not limited thereto. The thick portion 20 may be formed at least in a region including the sealing end surface 5 or at least in a region including the vicinity of the sealing end surface 5 (a position existing in the range).

On the other hand, four diagonal portions 13 (FIG. 7) forming interconnecting portions of the respective side wall constituting portions 14 on the sealing end face 12 side of the body portion 11 of the glass funnel 2 for a color cathode ray tube (hereinafter simply referred to as a funnel). (See FIG. 2B), a thick portion 21 (see FIG. 2) which is relatively thicker than other portions of each side wall constituting portion 14 is integrally formed.
When the funnel 2 is viewed from a direction perpendicular to the sealing end face 12, the thick portion 21 has the same configuration as that shown in FIG. The thick portion 21 of the funnel 2 may have the same or substantially the same shape as the sealing end face 12 or the vicinity thereof as the above-described sealing end face 5 of the panel 1 or the vicinity thereof. Therefore,
The thick portion 21 at or near the sealing end surface 12 of the diagonal portion 13 of the funnel 2 has the same size or substantially the same size as the thick portion 20 at or near the sealing end surface 5 of the diagonal portion 7 of the panel 1. Further, they are formed at the same position or substantially the same position. The neck portion 1 of the thick portion 21 of the funnel 2
The end position and the like on the 0 side are not limited.

As shown in FIG. 4, the glass tube 31 for a cathode ray tube is manufactured by sealing the frit glass 30 between the sealing end face 5 of the panel 1 and the sealing end face 12 of the funnel 2. Is done. In this case, the thick part 20 of the panel 1 and the thick part 21 of the funnel 2 are formed at corresponding positions (the same or substantially the same position) in the sealing direction. More specifically, the sealing end faces 5, 12 of the panel 1 and the funnel 2, or the vicinity thereof, have the same or substantially the same form when viewed from a direction perpendicular to the sealing end face. Therefore, in the glass bulb 31 for a cathode ray tube, the sealing between the panel 1 and the funnel 2 is properly performed without generating an unreasonable step.

FIG. 5 is a perspective view of a panel according to a second embodiment of the present invention, and FIG. 6 is a schematic enlarged plan view showing the periphery of a diagonal portion of the panel. As shown in FIG. 5, the panel 1 according to the second embodiment also has four diagonal portions 7, which are interconnecting portions of the respective side portions 8 of the skirt portion 6, other than the respective side portions 8. A thick portion 40 which is relatively thicker than the portion (the central portion in the longitudinal direction of the sealing end face) is integrally formed.

As shown in FIG. 6, the thick portion 40 is formed so as to have a maximum thickness t ₁ on the diagonal axis X, and seals each side 8 from the diagonal axis X. Equal thickness portions 40 of predetermined dimensions a and b, respectively, toward the center in the longitudinal direction of the end surface.
a, 40b are formed. These two equal parts 40
In the present embodiment, the dimensions a and b of a and 40b are the same, and are set, for example, in the range of 5 mm or more and 80 mm or less. The thickness of the thick portion 40 is gradually reduced from the end of the equal thickness portions 40a and 40b on the central side in the longitudinal direction of the sealing end surface, and is equal to or substantially equal to the thickness of the central portion in each side portion 8. Has a thickness t ₀ . Also, a thick portion similar to the thick portion 40 is formed in a region including the sealing end surface of the funnel constituting the glass bulb for a cathode ray tube or the vicinity thereof by sealing with the panel 1. Except for the above-described configuration in the second embodiment, the configuration is the same as that in the first embodiment. Therefore, in FIG. 5 and FIG. 6, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can achieve a remarkable effect in comparison with the conventional example as follows.

As a first embodiment of the present invention, the aspect ratio is 4: 3, the outer diameter in the diagonal axis X direction is 724.8 mm, and the radius of curvature of the face outer surface on the diagonal axis X is 10,000.
A 0 mm panel was produced under the following conditions. That is,
As for the thickness distribution at or near the sealing end face of the diagonal portion in the skirt portion, the form shown in FIG. 2 is adopted, and the thickness t ₁ on the diagonal axis X of the thick portion is 13.3 m.
m, the thickness was gradually reduced from the diagonal axis X to the center in the longitudinal direction of the sealing end face of each side in a dimension range of 100 mm to reach a thickness t _{0 of} 11.4 mm. In this case, the thickness of the sealing end face other than the thick part was 11.4 mm in any part.

As a second embodiment of the present invention, similarly, the aspect ratio is 4: 3, and the outer diameter in the diagonal axis X direction is 724.8 m.
m and the radius of curvature of the face outer surface on the diagonal axis X is 1
A 00000 mm panel was produced under the following conditions. That is, the thickness distribution at or near the sealing end face of the diagonal portion in the skirt portion is assumed to adopt the form shown in FIG. 6, and the thickness t ₁ on the diagonal axis X of the thick portion is set to 13. on which was 3 mm, over the diagonal axis X in a size range of 60mm to the seal end face longitudinal central portion of each side to form a constant wall portion made in the thickness t _1, these like meat portion From the end of the central portion in the longitudinal direction of the sealing end face
The thickness is gradually reduced within a range of 0 mm to 11.4 mm.
Of thickness t ₀ . In this case, the thickness of the sealing end face other than the thick part is 11.4 mm in any part.
And

As a third embodiment of the present invention, similarly, the aspect ratio is 4: 3, and the outer diameter in the diagonal axis X direction is 724.8 m.
m and the radius of curvature of the face outer surface on the diagonal axis X is 1
A 00000 mm panel was produced under the following conditions. That is, the thickness distribution of the seal end face or near the opposite corners of the skirt portion is intended to take the form shown in FIG. 6, the thickness t ₁ on the diagonal axis X in the thick portion 17. on which was 0 mm, to extend from the diagonal axis X in a size range of 60mm to the seal end face longitudinal central portion of each side to form a constant wall portion made in the thickness t _1, these like meat portion From the end of the central portion in the longitudinal direction of the sealing end face
The thickness is gradually reduced within a range of 0 mm to 11.4 mm.
Of thickness t ₀ . In this case, the thickness of the sealing end face other than the thick part is 11.4 mm in any part.
And

As a conventional example, that is, as a comparative example, similarly, the aspect ratio is 4: 3, and the outer diameter in the diagonal axis X direction is 724.8 m.
m and the radius of curvature of the face outer surface on the diagonal axis X is 1
A 00000 mm panel was produced under the following conditions. That is, the thickness t ₀ of the sealing end face is set to 11.4 mm over the entire circumference without forming a thick portion at the diagonal portion of the skirt portion.
And

The panels according to each of the above Examples and Comparative Examples were molded using a predetermined press die. In this molding process, no molding defects such as cracks were found in any of the molding processes. . Next, the amount of thermal displacement in the direction along the panel center axis (tube axis Z) for the outer surface of the sealing end face at the diagonal when the panels according to each of the examples and comparative examples were heated to 450 ° C. z and the thermal tensile stress value were calculated by simulation. The calculation results are shown in Table 1 below.

[0054]

[Table 1]

As is clear from Table 1 above, Example 1
According to the panels of (1) to (3), since the thermal expansion of the panel is suppressed in the vicinity of the sealing end face of the diagonal part, the outer surface part of the sealing end face at the diagonal part of the panel particularly during the heat treatment step for the panel It has become possible to reduce the value of the thermal tensile stress, which is the maximum principal stress that occurs in steel. As a result, for example, in a heating process in a sealing step in which frit glass is applied to both sealing end surfaces of the panel and the funnel and sealed, diagonal portions are sealed with thermal expansion of the panel. It is possible to efficiently avoid the problem that the glass is broken starting from the vicinity of the end surface.

A funnel having an aspect ratio of 4: 3 and an outer diameter of 724 mm in the diagonal axis direction (deflection angle 120
Regarding (°), a thick portion having the same sealing end face thickness distribution was formed at the same size position so as to face the thick portion of the panels according to Examples 1 to 3 and Comparative Example. Then, these funnels are set on a predetermined jig, and frit glass (ASHIGAKU GLASS CORPORATION; AS) is placed on the sealing end face of the funnel.
A slurry prepared by dispersing F-1307B) in an organic vehicle was applied and dried, and then the corresponding panel was placed on the sealing end face. After this,
By passing through a heat treatment furnace having a predetermined temperature gradient maintained at a maximum temperature of 450 ° C. for 20 minutes and reacting the frit glass with the sealing end face of the panel and the funnel,
Glass bulbs for cathode ray tubes were obtained by sealing panels and funnels corresponding to Examples 1 to 3 and Comparative Example, respectively.

In this case, as a result of executing a process of sealing the frit glass through a heat treatment furnace for each of ten glass bulbs corresponding to the above-mentioned Examples 1 to 3 and Comparative Example, the glass bulb corresponding to Examples 1 to 3 was obtained. In each case, triangular cracks due to thermal tensile stress did not occur, but in the case of Comparative Example, the occurrence of triangular cracks or breakage similar thereto was observed. Further, as a result of examining the pressure resistance of each of the glass bulbs corresponding to Examples 1 to 3, it was found that each of the bulbs had a pressure resistance of 3.
It was sufficiently large at 5 kg / cm ² or more, and it was confirmed that even when the inside of the glass bulb for a cathode ray tube was evacuated to a high vacuum, the formation of the thick portion did not adversely affect the mechanical strength of the glass bulb.

[0058]

As described above, according to the present invention, in a cathode ray tube panel having a substantially rectangular face portion forming an effective screen having a radius of curvature of the outer surface on the diagonal axis of not less than 10,000 mm, a skirt portion is provided. Since the thick portion is formed in the diagonal portion and in a region including at least the sealing end face or its vicinity in the direction parallel to the tube axis, thermal deformation of the skirt portion is suppressed and mechanical strength against thermal stress is reduced. Enhanced. As a result, during the heating process when sealing the panel and the funnel with the frit glass through the heat treatment furnace, triangular cracks due to thermal stress concentration generated around the sealing end face at the diagonal portion due to thermal expansion deformation of the panel. The occurrence of breakage is effectively avoided.

In particular, by forming the thick portion in a heat stress concentration region at the time of heat treatment at the diagonal portion of the panel,
The occurrence of the triangular cracks and the like can be avoided with high reliability without waste and efficiently.

The thickness t ₁ on the diagonal axis of the thick portion is 1.05 ≦ t.sub.0 with respect to the thickness t ₀ of the corresponding portion at the center in the longitudinal direction of the sealing end face of each side. ₁ / t ₀ ≦
By having the relationship of 1.50, the occurrence of molding defects such as wrinkles and cracks due to a longer time during which the press is applied during the molding of the panel is avoided. The mold can be easily removed, and a sufficient effect of increasing mechanical rigidity against thermal expansion deformation can be obtained.

Further, when the thick portion is 5 mm or more from the diagonal axis toward the center in the longitudinal direction of the sealing end face of each side, the thickness is 80 mm or more.
By being formed in a uniform thickness t ₁ in the range mm, the thermal stress concentrated on the seal end face side of the diagonal portion of the panel, dispersed in each side direction away from the diagonal portion Thus, for example, even if the panel is enlarged, the occurrence of the damage described above is reliably suppressed.

Further, the thickness t ₁ of the thick portion gradually decreased toward the center in the longitudinal direction of the sealing end face of each side to reach the thickness t ₀ , so that the thick portion was formed. Nevertheless, there is no sudden change in wall thickness, and the wall thickness gradually decreases from t ₁ to t ₀ , which hinders the filling of the molten glass in the press die during panel molding. This can be performed smoothly without causing molding defects such as wrinkles and cracks in the thickness-changed portion.

Further, the present invention relates to a glass bulb for a cathode ray tube obtained by joining and welding a sealing end face of a funnel and a sealing end face of a panel. The shape of the sealing end face of the panel or its vicinity is adapted to avoid the shape defect of the sealing part between the panel and the funnel, especially the joint part due to mismatch of the sealing part at the diagonal part of both. The effect of suppressing the increase in the contact strength and the occurrence of breakage can be obtained.

[Brief description of the drawings]

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

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

FIG. 3 is an enlarged schematic vertical sectional front view showing the glass panel for a cathode ray tube according to the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional front view showing a glass tube for a cathode ray tube obtained by joining and welding a glass panel for a cathode ray tube and a glass funnel for a cathode ray tube according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing a glass panel for a cathode ray tube according to a second embodiment of the present invention.

FIG. 6 is an enlarged plan view showing a main part of a glass panel for a cathode ray tube according to a second embodiment of the present invention.

FIG. 7A is a perspective view showing a conventional glass panel for a cathode ray tube, and FIG. 7B is a perspective view showing a conventional glass funnel for a cathode ray tube.

FIG. 8 is a schematic plan view showing a main part of a conventional glass panel for a cathode ray tube (funnel).

FIGS. 9A and 9B are schematic perspective views schematically showing a glass panel for a cathode ray tube showing a conventional problem.

FIG. 10A is a schematic plan view of a main part of a glass panel for a cathode ray tube showing a conventional problem, and FIG.
It is a principal part schematic longitudinal front view of the glass panel for cathode ray tubes which shows the conventional problem.

FIG. 11 is an enlarged schematic front view of a main part of a glass panel for a cathode ray tube showing a conventional problem.

[Explanation of symbols]

 Reference Signs List 1 panel (glass panel for cathode ray tube) 2 funnel (glass funnel for cathode ray tube) 3 face portion 4 blend R portion 5 sealing end surface (sealing end surface of panel) 6 skirt portion 7 diagonal portion (diagonal portion of panel) 8 sides Part 12 Sealing end face (sealing end face of funnel) 13 Diagonal part (diagonal part of funnel) 14 Side wall forming part of funnel 20 Thick part (thick part of panel) 21 Thick part (thick part of funnel) 31) Glass bulb for cathode ray tube 40 Thick part (thick part of panel)

Claims (6)

[Claims] 1. An outer surface having a radius of curvature of 1 on a diagonal axis.
A substantially rectangular face portion that forms an effective screen of 0000 mm or more, and a skirt portion having peripheral edges connected to the periphery of the face portion via a blend R portion and having a substantially rectangular sealing end surface at an open end; In a panel for a cathode ray tube, comprising: a diagonal portion of the skirt portion and a region including at least a sealing end face or a vicinity thereof in a direction parallel to the tube axis;
A glass panel for a cathode ray tube, wherein a thicker portion is formed which is thicker than a portion corresponding to the region at a central portion in a longitudinal direction of a sealing end face of each side portion. 2. The glass panel for a cathode ray tube according to claim 1, wherein the thick portion is formed in a thermal stress concentration region during heat treatment. 3. The thickness t _{1 of the} thick portion on a diagonal axis.
Have a relationship of 1.05 ≦ t ₁ / t ₀ ≦ 1.50 with respect to the thickness t ₀ of a corresponding portion in the longitudinal center of the sealing end face of each side. Item 3. A glass panel for a cathode ray tube according to item 1 or 2. 4. The thick portion has a length of 5 mm or more from the diagonal axis toward the center in the longitudinal direction of the sealing end face of each side portion.
CRT glass panel according to any one of claims 1 to 3, characterized in that it is formed to a uniform thickness t ₁ in the range of mm. 5. The thick portion, wherein the thickness t ₁ gradually decreases toward the center in the longitudinal direction of the sealing end face of each of the sides to reach the thickness t _0. The glass panel for a cathode ray tube according to any one of claims 1 to 4. 6. The sealing end face of a glass funnel for a cathode ray tube having a funnel-shaped body having a substantially rectangular sealing end face at a large diameter opening end, the diameter gradually increasing from the small diameter side opening end. Item 6. A glass bulb for a cathode ray tube obtained by joining and welding a sealing end surface of a glass panel for a cathode ray tube according to any one of Items 1 to 5, wherein the form of the sealing end surface of the glass funnel for a cathode ray tube or the vicinity thereof is the A glass bulb for a cathode ray tube, which corresponds to a form of the sealing end face of the glass panel for a cathode ray tube according to any one of claims 1 to 5 or a vicinity thereof.