JP2002237266A - Glass funnel for cathode-ray tube and glass bulb for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a lighter weight and maintain strength against vacuum breakage. SOLUTION: A thickness S of a seal edge face 3c1 of a funnel 3 is set to be almost equal to a thickness S' of a seal edge face 2b1 of a panel 2. A body portion 3e of the funnel 3 has a first region 3e1 with its size h ranging from the seal edge face 3c1 to a direction parallel to a tube axis Z and a second region 3e2 except the first region 3e1. The thickness of the second region 3e2 is relatively smaller than the thickness of the first region 3e1. As a result, a boundary between both regions forms a stepped portion 3e3 on the outer face of the body portion 3e.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a glass funnel and a glass bulb for a cathode ray tube used for television reception and the like.

[0002]

2. Description of the Related Art As exemplified in FIG. 9, a glass bulb 11 constituting a cathode ray tube for television reception or the like has a glass panel (hereinafter referred to as "panel") 12 on which an image is projected and a back portion thereof. It comprises a funnel-shaped glass funnel (hereinafter referred to as “funnel”) 13 to be formed, and a neck portion 14 to which an electron gun is attached. Neck 14
Is welded to the small opening of the funnel 13. Panel 1
Reference numeral 2 denotes a face portion 12a serving as a visual image area;
a skirt portion 12b extending substantially perpendicularly from the periphery of the skirt portion 12a, and a seal edge surface 12b1 provided on an end face of the skirt portion 12b and a seal provided on a large opening of the funnel 13 as shown in an enlarged manner in FIG. Edge surface 13c1
Are bonded to each other via a sealing glass 15 for sealing.

[0003] The glass bulb 11 for a cathode ray tube constructed as described above is used as a vacuum container by exhausting the inside after mounting an electron gun on the neck portion 14 (the internal pressure after the exhaustion is For example, about 10 -8 Torr.) Therefore, a stress due to a load of the atmospheric pressure is generated on the outer surface of the glass bulb 11 (hereinafter, this stress is referred to as “vacuum stress”), and the glass bulb 11 can withstand a breakdown (vacuum breakdown) caused by the vacuum stress. It is required to have sufficient mechanical and structural strength. That is, if these strengths are insufficient, not only the glass bulb 11 cannot withstand the above-mentioned vacuum stress, but may cause fatigue failure, and also may suffer from external flaws such as fine scratches on the outer surface and impact load. It is predicted that the progress of the above-mentioned fatigue fracture will be accelerated when a statistical factor is added. Further, in the manufacturing process of the cathode ray tube, since the temperature of the glass bulb 11 is raised to about 400 ° C., there is a possibility that the glass bulb 11 may be broken by a synergistic effect of the thermal stress generated by the temperature rise and the above-mentioned vacuum stress.

The above-mentioned vacuum stress acts as a compressive stress and a tensile stress on the glass bulb 11 because the glass bulb 11 has a non-spherical shape, and these stresses generally show a distribution as shown in FIG. FIG. 11 (a)
(B) and (c) show the stress distribution in the short axis section, the long axis section, and the diagonal axis section of the glass lube 11, respectively. In these stress distribution diagrams, the region indicated by the inward arrow indicates the compressive stress. , And the region indicated by an outward arrow indicates a region where a tensile stress acts.

In general, the breaking strength of a glass structure is weaker than a tensile stress than a compressive stress. In a glass bulb 11 for a cathode ray tube as a vacuum vessel, a tensile stress generated by a vacuum stress (hereinafter, this stress is referred to as a “tensile vacuum stress”) ) Acts, that is, a region extending from the periphery of the face portion 12a of the panel 12 to the skirt portion 12b and a peripheral region of the seal edge surface 13c1 of the funnel 13 as a starting point. In particular, the seal edge surface 12b1 of the panel 12 and the seal edge surface 1 of the funnel 13
3c1 is joined via the sealing glass 15 for sealing, and the joint becomes a weak point in strength, while the tensile vacuum stress shows a peak value in a region near the joint. a) (b)｝, it is important to take measures to prevent destruction starting from the joint. For this reason, in the conventional glass bulb 11 for a cathode ray tube,
The required breaking strength is secured by increasing the wall thickness.

[0006]

Recently, there has been a demand for flat screens and large screens for displays for television reception and the like. Along with this, cathode ray tubes are also becoming flatter and flatter, but as a result, the shape of glass bulbs for cathode ray tubes is more distant from spherical shapes than ever before, and the degree of uneven distribution of vacuum stress distribution is increasing. As a result, the level of strength required for glass bulbs for cathode ray tubes has become more severe. As a result, the thickness of the glass bulb for a cathode ray tube is further increased, and the weight is thereby increased. An increase in the weight of the glass bulb for a cathode ray tube not only causes inconvenience in transportation and handling, but also causes an increase in the weight of a final product having a built-in cathode ray tube, which is one of the causes of a decrease in commercial value. In particular, the tendency is large in a large glass bulb for a cathode ray tube.

Under the circumstances described above, the weight of the glass bulb for a cathode ray tube is required to be reduced. On the other hand, with the flattening and flattening of the cathode ray tube, the degree of uneven distribution of vacuum stress acting on the glass bulb for a cathode ray tube is also increased. It is also important to ensure sufficient strength to withstand vacuum breakage.

An object of the present invention is to provide a glass funnel for a cathode ray tube which is lightweight and can secure sufficient strength to withstand a vacuum break when the cathode ray tube is constructed.

Another object of the present invention is to provide a glass bulb for a cathode ray tube provided with a glass panel for a cathode ray tube having a substantially flat outer surface of a face portion, while reducing the weight and having sufficient strength to withstand vacuum breakage. Is to provide a configuration that can ensure the above.

[0010]

In order to solve the above-mentioned problems, the present invention provides a funnel shape having a large opening at one end and a small opening at the other end, and molds from the sealing edge surface of the large opening. In a cathode ray tube glass funnel provided with a seal edge portion reaching the match line, a yoke portion provided on the small opening side, to which a deflection yoke is mounted, and a body portion connecting the mold match line and the yoke portion, The thickness of the seal edge surface is substantially equal to the thickness of the seal edge surface of the glass panel for a cathode ray tube to be joined thereto, and the body portion has a dimension h in a direction parallel to the tube axis from the seal edge surface.
And an area other than the area of the dimension h,
When the cathode ray tube is constructed, the area of the dimension h is in an area where a tensile vacuum stress caused by the vacuum pressure in the cathode ray tube acts, and the thickness of the other area is the thickness of the area of the dimension h. Therefore, the boundary between the area of the dimension h and the other area forms a step on the outer surface of the body, and the step ΔT of the step is smaller than the thickness S of the seal edge surface. An arrangement is provided wherein 0.06 ≦ ΔT / S ≦ 0.3.

Here, the "mold match line"
Among the molds used for press-molding the glass funnel for a cathode ray tube, a bottom mold (a mold having a funnel-shaped molding surface for molding a portion excluding a seal edge portion) constituting a female mold and a shell mold (A substantially rectangular annular mold that is positioned and mounted on a bottom mold and combined to accurately mold the seal edge portion).
A molten glass lump (glass gob) is supplied into a female mold composed of a bottom mold and a shell mold, and a plunger mold to be a male mold is pressed into the glass gob along a molding surface of the male and female molds. Roll to form a glass funnel for a cathode ray tube.

According to the glass funnel for a cathode ray tube having the above structure, the thickness S of the seal edge surface is made substantially equal to the thickness of the seal edge surface of the glass panel for a cathode ray tube. Is sufficiently secured, and the joining with the sealing glass for sealing or the like can be easily and firmly performed. Thus, the strength of the joint between the panel and the funnel can be sufficiently ensured.

The body portion is divided into a region having a dimension h in a direction parallel to the pipe axis from the seal edge surface and another region excluding the region having the dimension h. Is given. That is, the thickness of the other region is relatively smaller than the thickness of the region having the dimension h.

As described above, in the conventional glass bulb for a cathode ray tube, on the long side and the short side, the tensile vacuum stress shows a peak value in the region near the junction between the panel and the funnel. (B)｝. On the other hand, in the glass funnel for a cathode ray tube according to the present invention, the body portion has the above-described configuration, the region having the relatively large thickness h is located on the seal edge portion side, and the other portion having the relatively small thickness. Is provided on the side of the small opening, when the cathode ray tube is constructed, the peak of the tensile vacuum stress on the long side and the short side is smaller than the area near the joint between the panel and the funnel. Side (neck side) (see FIG. 7 described later).
reference). As a result, the tensile vacuum stress acting on the joint, which is a weak point in strength, is reduced, and the strength against vacuum breakage is further improved. In addition, by providing the other region having a relatively small thickness, the weight of the glass funnel for a cathode ray tube can be reduced.

[0015] For the above reason, by giving the thickness relationship between the area of the dimension h and the other area, the boundary between the two areas forms a step on the outer surface of the body. If the step ΔT of the step portion is too small, the thickness reduction of the other region becomes insufficient, and the effect of reducing the weight of the glass funnel for a cathode ray tube and the moderating effect of the tensile vacuum stress acting on the above-mentioned joint portion can be sufficiently obtained. Absent. On the other hand, if the step ΔT is too large, the thickness of the other region becomes too small, and the strength against vacuum stress is insufficient. In order to sufficiently achieve the effect of reducing the weight of the glass funnel for the cathode ray tube and the effect of reducing the tensile vacuum stress acting on the above-mentioned joint, and to secure the required strength, the step ΔT is set to 0 with respect to the thickness S of the seal edge surface. 0.06 ≦ ΔT / S ≦ 0.3, preferably 0.06
It is set to be within the range of ≦ ΔT / S ≦ 0.2.

In the above structure, the dimension h is determined by the thickness S of the seal edge surface from the viewpoint of reducing the weight of the glass funnel for the cathode ray tube and sufficiently reducing the tensile vacuum stress acting on the joint. 0.5 ≦ h / S ≦
It is preferable to set so as to fall within the range of 1.5.

[0017] In the above configuration, the thickness T of the other areas, with respect to the thickness T _R at the boundary between the stepped portion 0.5
It is preferable to be within the range of ≦ T / T _R ≦ 1. here,
The “thickness T” is a thickness at an arbitrary position in the other region except for a boundary (thickness T _R ) with the step.

In the above structure, the outer surface of the area having the dimension h is an inclined surface expanding toward the mold match line, and an angle A between the outer surface and a plane orthogonal to the mold match line is defined. It is preferable to set within the range of 3 ° ≦ A ≦ 15 °. As a result, the releasability from the molding die is enhanced, the occurrence of scratches with the molding die on the outer surface of the area of the dimension h is prevented, and the effect of providing the area of the dimension h is effectively reduced. Can be closed. Alternatively, the outer surface of the area of the dimension h is a curved surface expanding toward the mold match line, and the angle B between the tangent plane of the outer surface in the mold match line and a plane parallel to the pipe axis is 3 ° ≦. The angle may be set in the range of B ≦ 15 °. Thereby, the same effect as described above can be obtained.

According to another aspect of the present invention, there is provided a face part having a substantially flat outer surface, a skirt part connected to a peripheral edge of the face, and a seal edge surface provided on an end face of the skirt part. A glass panel for a cathode ray tube, a glass funnel for a cathode ray tube having the above-described structure, and a neck portion to which an electron gun is attached, which is joined to a small opening of the glass funnel for a cathode ray tube, and a sealing edge of the glass panel for a cathode ray tube. Provided is a glass bulb for a cathode ray tube, wherein the surface and a seal edge surface of a glass funnel for a cathode ray tube are joined to each other.

Here, "substantially flat" means that the radius of curvature of the generatrix along the diagonal axis of the outer surface of the face portion is 100.
It means that it is 00 mm or more.

As described above, the cathode ray tube glass bulb provided with the cathode ray tube glass panel in which the outer surface of the face portion is substantially flat, the weight tends to increase in relation to the strength. According to the glass bulb for a cathode ray tube described above, the contradictory characteristics of strength and weight reduction can be provided in a well-balanced manner due to the above-mentioned effects on the glass funnel for a cathode ray tube.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a glass bulb 1 for a cathode ray tube according to this embodiment. The glass bulb 1 constitutes a cathode ray tube for television reception or the like, and has a glass panel (hereinafter, referred to as “panel”) 2 on which an image is projected.
And a funnel-shaped glass funnel (hereinafter, referred to as “funnel”) 3 forming a back portion thereof, and a neck portion 4 to which an electron gun is attached.

The panel 2 has a face portion 2a serving as a visual image area.
And a skirt portion 2b that extends substantially perpendicularly from the periphery of the face 2a. As shown in FIG. 2, a seal edge surface 2b1 is provided on an end surface of the skirt portion 2b. The outer surface of the face portion 2a is a substantially flat surface having a radius of curvature of a generatrix of 10,000 mm or more along a diagonal axis thereof.

As shown in FIGS. 3 and 4, the funnel 3
Has a funnel shape having a large opening 3a at one end and a small opening 3b at the other end, and a sealing edge surface 3c of the large opening 3a.
1, a seal edge portion 3c extending from the mold match line 3c2 to the mold match line 3c2, a yoke portion 3d provided on the side of the small opening 3b to which a deflection yoke is mounted, and a mold match line 3c.
And a body portion 3e connecting the yoke portion 3 and the yoke portion 3d. The neck portion 4 is welded to the small opening 3b of the funnel 3. Here, the body part 3e and the yoke part 3d are continuous with each other at a boundary plane U which is orthogonal to the tube axis Z and passes through a position that is a bending point of the outer surface shape. The boundary surface U is usually
It is located slightly closer to the large opening 3a than TOP (top of round: a starting position where the circular cross-sectional shape on the side of the small opening 3b gradually changes to a rectangular cross-sectional shape on the side of the large opening 3a).

As shown in FIG. 1, the panel 2 and the funnel 3 to which the neck portion 4 is welded are mutually welded to each other at the sealing edge surfaces 2b1 and 3c1 via the sealing glass 5 for sealing. Thereby, the glass bulb 1 as a vacuum container is constituted.

FIG. 5 shows the periphery of the large opening 3 a of the funnel 3.

The thickness S of the seal edge surface 3c1 is set to be substantially equal to the thickness S 'of the seal edge surface 2b1 of the panel 2. Thereby, both seal edge surfaces 2b
The bonding area between 1,3c1 is sufficiently ensured, and bonding by the sealing glass 5 for sealing can be performed easily and firmly. Here, the thickness S of the seal edge surface 3c1 is set such that when the corner of the large opening 3a is chamfered C (or rounded at the time of molding) as shown in FIG.
(Or roundness) in the thickness direction. The same applies to the seal edge surface 2b1 of the panel 2.

The body 3e has a seal edge surface 3c1.
And a region 3e1 having a dimension h in a direction parallel to the tube axis Z, and another region 3e2 excluding the region 3e1. The thickness of the other region 3e2 is relatively smaller than the thickness of the region 3e1 having the dimension h.
A step 3e3 is formed on the outer surface of the e.
For convenience of explanation, the area 3e1 having the dimension h is referred to as “the first area 3”.
e1 ", and the other area 3e2 is referred to as a" second area 3e2 ". ).

The dimension h of the first region 3e1 is set within the range of 0.5 ≦ h / S ≦ 1.5 with respect to the thickness S of the seal edge surface 3c1, and the first region 3e1 is When the cathode ray tube is constructed together with the panel 2, the cathode ray tube is located in a region where a tensile vacuum stress caused by a vacuum pressure in the cathode ray tube acts (see FIG. 7). Also, the step Δ of the step 3e3
T is 0.0 with respect to the thickness S of the seal edge surface 3c1.
6 ≦ ΔT / S ≦ 0.3, preferably 0.06 ≦ ΔT / S
It is set within the range of ≦ 0.2. Further, the second region 3e
Thickness T at any position of 2 is set in the range of 0.5 ≦ T / T _R ≦ 1 with respect to the thickness T _R at the boundary between the stepped portion 3e3.

Further, in this embodiment, the step 3e3
Are formed by two curved surfaces 3e31 and 3e32, and the radius of curvature R1 of the curved surface 3e31 on the first region 3e1 side and the radius of curvature R2 of the curved surface 3e32 on the second region 3e2 side are 1 ≦ R2.
/ R1 ≦ 3 and 2 ≦ R1 / ΔT ≦ 20. The step portion 3e3 is a portion where the thickness changes, and the vacuum stress tends to concentrate, but by forming this portion with the two curved surfaces 3e31 and 3e32, the stress concentration can be effectively reduced. In particular,
By setting the curvature radii R1 and R2 of the curved surfaces 3e31 and 3e32 so as to satisfy the above relationship, it is possible to prevent the funnel 3 from being chipped due to molding failure or flaws,
Stress concentration can be reduced.

The step 3e3 can be formed by combining three or more curved surfaces. In this case, the radius of curvature R1 of the curved surface closest to the first region 3e1 and the radius of curvature R2 of the curved surface closest to the second region 3e2 are preferably set to satisfy the above relationship. Step 3
e3 may be formed by one curved surface or a linear surface, or may be formed by appropriately combining one or more curved surfaces and a linear surface.

Further, in this embodiment, the first region 3e
1 is an inclined surface expanding toward the mold match line 3c2, and an angle A between the outer surface and a plane Z ′ parallel to the pipe axis Z is within a range of 3 ° ≦ A ≦ 15 °. You have set. Thereby, the releasability from the mold at the time of press-molding the funnel 3 is enhanced, the occurrence of scratches on the outer surface of the first region 3e1 with the molding die is prevented, and the first region 3e1 is provided. The effect of the above can be made effective.

The dimensions h, ΔT, T _R , and T are determined in accordance with the criteria shown in FIG. First, on a cutting plane parallel to the pipe axis Z, a normal line V1 of an outer surface passing through a boundary point P1 between the step portion 3e3 and the second region 3e2 (in the example shown in the drawing, a boundary between the curved surface 3e32 and the second region 3e2). Ask for. The intersection between the normal V1 and the inner surface is P2, and the normal V1 and the first area 3e.
When an intersection between an extension line W of the first outer surface and P3, T _R is the length of the line segment P1 · P2, [Delta] T is the length of the line segment P1 · P3. Next, a straight line Q passing through the center point (position of ΔT / 2) of the line segments P1 and P3 and orthogonal to the normal line V1 is a stepped portion 3e3.
A point P4 that intersects is obtained. The length of a line segment descending from the position of the seal edge surface 3c1 in a direction parallel to the pipe axis Z and reaching the position of the intersection P4 is h. T is the length of the line segment P1n · P2n, where P1n and P2n are the intersections of the normal Vn of the outer surface with the inner surface and the outer surface at an arbitrary position in the second region 3e2.

The glass bulb 1 for a cathode ray tube of this embodiment, which is constructed by joining the panel 2 and the funnel 3 to each other as described above, mounts an electron gun on the neck 4 and then exhausts the inside. (The internal pressure after evacuation is, for example, about 10 @ -8 Torr).
FIG. 7 schematically shows the distribution of vacuum stress in the short-axis section of the glass bulb 1 for a cathode ray tube of this embodiment.
In the figure, the region indicated by an inward arrow indicates a region where a compressive stress acts, and the region indicated by an outward arrow indicates a region where a tensile stress acts. The two-dot chain line shows the distribution of the vacuum stress in the short-axis cross section of the conventional glass bulb 11 for a cathode ray tube (FIG. 11A). As shown in the figure, in the conventional glass bulb 11 for a cathode ray tube, the tensile vacuum stress shows a peak value in the region near the joint between the panel and the funnel (two-dot chain line), but the glass bulb for the cathode ray tube of this embodiment 1, the peak of the tensile vacuum stress has a smaller opening 3b than the area near the joint between the panel 2 and the funnel 3.
Side (neck tube 4 side). This is funnel 3
In the body part 3e of the first
The region 3e1 is on the seal edge portion 3c side, and the second region 3e2 having a relatively small thickness is on the small opening portion 3b side (the neck tube 4).
Side), the tensile vacuum stress in the region near the joint is dispersed by the elastic deformation capability of the appropriately thinned second region 3e2, and is applied to the second region side 3e2. It is considered that the degree increased. Although not shown, the distribution of the vacuum stress in the long-axis cross section generally shows the same tendency as described above (however, the magnitude of the tensile vacuum stress is smaller than that in the short-axis cross section).

In the above embodiment, the tensile vacuum stress acting on the above-mentioned joint, which is a weak point on the strength, is reduced, so that the strength of the glass bulb 1 for a cathode ray tube against vacuum breakage is further improved. In addition, by providing the second region 3e2 having a relatively small thickness, it is possible to reduce the weight of the glass funnel 3 for a cathode ray tube, and hence the glass bulb 1 for a cathode ray tube. As described above, the glass funnel 3 for a cathode ray tube according to this embodiment, and the glass bulb 1 for a cathode ray tube according to this embodiment, have a good balance between the contradictory characteristics of strength and weight reduction. In FIGS. 4 and 5, the outer surface of the conventional funnel 13 shown in FIGS. 9 and 10 is represented by a dotted line, and the second region 3e2 of the funnel 3 of this embodiment is schematically shown as being thinned. ing.

In the embodiment shown in FIG. 8, the outer surface of the first region 3e1 of the funnel 3 is a curved surface (arc surface) expanding toward the mold match line 3c2. The tangent plane Z ″ of the outer surface in the mold match line 3c2
And an angle B between the plane Z ′ parallel to the tube axis Z is 3 ° ≦ B
It is set within the range of ≦ 15 °. As a result, the releasability from the mold at the time of press-molding the funnel 3 is enhanced, and the occurrence of scratches on the outer surface of the first region 3e1 with the molding die is prevented, and the first region 3e1 is provided. The effect of the above can be made effective.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Panel (flat panel) shown in FIG.
3 and a funnel of the form shown in FIGS. 3 to 6 (the outer surface of the first region is a curved surface as shown in FIG. 8) with a sealing glass for sealing, and a glass for a cathode ray tube of the form shown in FIG. A bulb was manufactured (Examples 1 to 11, Comparative Examples 1 and 2), and a comparative test was performed with a conventional glass bulb for a cathode ray tube (conventional example) shown in FIGS. Two kinds of comparative tests were performed. Comparative test 1 (Examples 1 to 6, Comparative Examples 1 and 2) was performed to confirm the influence of the set value of (ΔT / S). Comparative test 2 (Examples 7 to 11) This was performed to confirm the influence of the set value of (h / S). In each of Examples, Comparative Examples, and Conventional Examples, the maximum outer diameter of the diagonal axis was 76 cm, the valve deflection angle was 102 °, and the panel used had the following specifications.
Table 1 shows the results of Comparative Test 1 and Table 2 shows the results of Comparative Test 2. [Panel specifications] Panel center thickness: 13.5 mm Outer radius of curvature (minor axis direction): 100,000 mm Outer radius of curvature (long axis direction): 100,000 mm Outer radius of curvature (diagonal axis direction): 100,000 mm Inner radius of curvature (minor axis) Direction): 1480 mm Inner surface radius of curvature (major axis direction): 6240 mm Inner surface radius of curvature (diagonal axis direction): 5650 mm

[0039]

[Table 1]

[0040]

[Table 2] Comparative Test 1 based Evaluation as compared to (Example 1 to Example 6) In the conventional example, relaxation effect of the vacuum tensile stress at the junction and T _R located, and,
A weight reducing effect was observed. Further, as one standard of mechanical strength required for this kind of glass bulb, if it is intended to suppress the tensile vacuum stress value to 8.4 MPa or less, the tensile vacuum stress value (5.45 to 8.21 MPa) Was below the reference value (8.4 MPa). (Comparative Example 1) Compared with the conventional example, the effect of reducing the tensile vacuum stress and the effect of reducing the weight at the joint were not sufficient. (Comparative Example 2) as compared with the conventional example, relaxation effect of tensile vacuum stress at the joint, and, although the weight reduction effect was observed, the tensile at T _R position vacuum stress (8.63MP
a) exceeded the above reference value (8.4 MPa). Comparative Test 2 based Evaluation as compared to (Example 7 Example 11) conventional example, relaxation effect of tensile vacuum stress at the junction and T _R located, and the weight reducing effect was observed. Further, as one standard of mechanical strength required for this type of glass bulb, if it is intended to suppress the tensile vacuum stress value to 8.4 MPa or less, the tensile vacuum stress value (7.45 to 8.21 MPa)
a) was lower than the reference value (8.4 MPa).

As is clear from the results of the comparative test, the funnels of the examples have a good balance of strength and weight reduction characteristics as compared with the comparative example and the conventional example.

[0042]

According to the present invention, it is possible to provide a glass funnel for a cathode ray tube which is lightweight and can secure sufficient strength to withstand vacuum breakage when the cathode ray tube is constructed. Further, according to the present invention, in a glass tube for a cathode ray tube provided with a glass panel for a cathode ray tube having a substantially flat outer surface of a face portion, the weight is reduced, and a sufficient strength to withstand a vacuum break is secured. be able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in a direction parallel to a tube axis of a glass bulb according to an embodiment.

FIG. 2 is a perspective view of a panel according to the embodiment.

FIG. 3 is a perspective view of a funnel according to the embodiment.

FIG. 4 is a partial cross-sectional view in a direction parallel to a tube axis of the funnel.

FIG. 5 is a partially enlarged cross-sectional view showing a periphery of a large opening of a funnel.

FIG. 6 is a partially enlarged sectional view showing the periphery of a large opening of a funnel.

FIG. 7 is a diagram showing a vacuum stress distribution acting on the glass bulb according to the embodiment.

FIG. 8 is a partially enlarged cross-sectional view showing a periphery of a large opening of a funnel according to another embodiment.

FIG. 9 is a cross-sectional view in a direction parallel to a tube axis of a conventional glass bulb.

FIG. 10 is an enlarged partial cross-sectional view showing a peripheral portion of a junction between a panel and a funnel in a conventional glass bulb.

FIG. 11 is a view showing a vacuum stress distribution acting on a conventional glass bulb.

[Description of Signs] 1 Glass bulb 2 Panel 2b1 Seal edge surface 3 Funnel 3a Large opening 3b Small opening 3c Seal edge 3c1 Seal edge surface 3c2 Mold match line 3d Yoke 3e Body 3e1 Area of dimension h (first) Area) 3e2 Other area (second area) 3e3 Step

Claims (6)

[Claims] 1. A funnel shape having a large opening at one end and a small opening at the other end, and a seal edge portion extending from a seal edge surface of the large opening to a mold match line; A cathode yoke glass funnel provided with a yoke portion to which a deflection yoke is mounted and a body portion connecting the mold match line and the yoke portion, wherein the thickness of the seal edge surface is The thickness is substantially equal to the thickness of the seal edge surface of the glass panel for a cathode ray tube, and the body portion is a region having a dimension h in a direction parallel to the tube axis from the seal edge surface and another region excluding the region having the dimension h. The region of the dimension h is in a region where a tensile vacuum stress caused by a vacuum pressure in the cathode ray tube acts when the cathode ray tube is formed, and the thickness of the other region is the dimension of the dimension. The boundary between the area of the dimension h and the other area forms a step on the outer surface of the body, and the step ΔT of the step is the seal edge. A glass funnel for a cathode ray tube, wherein 0.06 ≦ ΔT / S ≦ 0.3 with respect to the thickness S of the surface. 2. The glass funnel for a cathode ray tube according to claim 1, wherein the dimension h satisfies 0.5 ≦ h / S ≦ 1.5 with respect to the thickness S of the seal edge surface. 3. A wall thickness T of the other regions, according to claim 1, characterized in that it is 0.5 ≦ T / T _R ≦ 1 with respect to the thickness T _R at the boundary between the stepped portion or the 2. The glass funnel for a cathode ray tube according to 2. 4. An outer surface of the area having the dimension h is an inclined surface expanding toward the mold match line, and
The angle A between the outer surface and a plane parallel to the tube axis is 3 ° ≦
4. The glass funnel for a cathode ray tube according to claim 1, wherein A ≦ 15 °. 5. An outer surface of the area of the dimension h is a curved surface expanding toward the mold match line, and a tangent plane of the outer surface in the mold match line;
4. The glass funnel for a cathode ray tube according to claim 1, wherein an angle B between the plane and the plane parallel to the tube axis satisfies 3 ° ≦ B ≦ 15 °. 6. A glass panel for a cathode ray tube, comprising: a face portion having a substantially flat outer surface; a skirt portion connected to a peripheral edge of the face; and a seal edge surface provided on an end surface of the skirt portion. The glass funnel for a cathode ray tube according to any one of 1 to 5, and a neck portion which is joined to a small opening of the glass funnel for a cathode ray tube and to which an electron gun is attached, and a sealing edge surface of the glass panel for a cathode ray tube; A glass bulb for a cathode ray tube configured by joining a seal edge surface of the glass funnel for a cathode ray tube to each other.