JPH0364982B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cathode ray tube, and particularly to a glass panel thereof.

[Technical background of the invention and its problems]

Generally, as shown in FIG. 1, the envelope of a cathode ray tube consists of a glass panel 1 having a substantially rectangular shape and having a fluorescent screen on its inner surface, and a joint 3 joining this glass panel 1 through a fritted glass or the like. It is composed of a funnel-shaped funnel 2. Further, on the opposite side of the funnel 2 from the glass panel 1, a net containing an electron gun is connected. In addition, the glass panel 1 has a face portion 1 which corresponds to a substantially rectangular frame for transmitting a fluorescent screen.
-2 and a skirt portion 1-3 corresponding to the rectangular frame. Generally, the length of the rectangular frame of the face portion 1-2 in the vertical axis Y-Y' direction is the horizontal axis X-
It is configured and arranged so that it is shorter than the length in the X′ direction. Furthermore, since the actual image is displayed by deflecting and scanning the electron beam from an electron gun (not shown) using, for example, the NTSC method, the difference in travel distance and collection speed of the electron beam between the center and the periphery of the face part is calculated. It is formed into a curved shape that bulges outward to reduce the size. FIG. 2 shows a cross-sectional view of such a glass panel. The outer radius of curvature of the face portion is a single radius of curvature, that is, part of a sphere, and
-2V, horizontal axis direction 1-2H and diagonal axis direction 1-
Letting the 2D radii of curvature be R _V , R _H and R _D , respectively, R _V =R _H =R _D. In addition, in FIG. 2, for the sake of simplicity, the vertical axis direction and the diagonal axis direction are shown together on the right side of the center line, and the horizontal axis direction is shown together on the left side. In addition, the inner radius of curvature of the face part is a single radius of curvature like the outer surface, and the radii of curvature in the vertical axis direction, horizontal axis direction, and diagonal axis direction are R _V ′ and R _H ′, respectively.
and R _D ′, R _V ′=R _H ′=R _D ′. Therefore, the height of the skirt section from the rectangular frame of the face section to the joint section 3 in the tube axis direction is 1- in the vertical axis direction.
3V, horizontal axis direction 1-3H and diagonal axis direction 1-3
If V is CHV, CHH and CHD, respectively,
CHV>CHH>CHD. Furthermore, if the thickness of the face portion near the outer frame in the vertical axis direction, horizontal axis direction, and diagonal axis direction is t _V , t _H and t _D , from the relationship between the radius of curvature of the outer surface and inner surface, t _V < t _H <t _D.

In such a glass panel, the larger the tube becomes, the larger the difference in the height of the skirt portion and the wall thickness of the face portion near the outer frame in each axis, which has an unfavorable mechanical effect on the envelope. In other words, the physical expansion stress Ps from the external atmospheric pressure due to evacuation of the glass panel is concentrated near the rectangular frame, and the stresses in the vertical, horizontal, and diagonal axes (P _SV ), (P _SH ) and (P _SD ) are (P _SV )＞
(P _SH ) > (P _SD ). That is, the maximum stress strain is applied in the vertical axis direction. However, in conventional glass panels, the wall thickness in the vertical axis direction, where the maximum stress and strain is applied, is on the contrary the smallest. Therefore, implosion can easily occur if a shock is applied to the glass panel, or if the glass panel has weak mechanical strength due to a slight defect. In addition, the impact force on the glass panel is transmitted to the joint between the glass panel and the funnel, but this joint has lower mechanical strength than other parts, so if the distance between the point of impact and the joint is short, this Implosion is likely to occur because the impact force reaches the joint before it is significantly attenuated. This risk is particularly high in conventional glass panels where the skirt height in the diagonal axis direction is extremely small.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object of the present invention is to provide a cathode ray tube having a glass panel with excellent mechanical strength.

[Summary of the invention]

The present invention relates to the vertical, horizontal and diagonal axis heights from the end of the substantially rectangular frame of the face of the glass panel to the junction of the skirt and funnel of the glass panel. When the thicknesses are respectively CHV, CHH and CHD, and the wall thicknesses in the vertical axis direction, horizontal axis direction and diagonal axis direction near the substantially rectangular frame of the face part are respectively _tV , _tH and _tD , By setting CHVCHHCHD and t _V t _H t _D , the distribution of the radius of curvature of each axis on the inner and outer surfaces of the face portion is substantially changed, resulting in a cathode ray tube with excellent mechanical strength.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to FIG. The glass panel shown in Fig. 3 corresponds to Fig. 2, and the glass panel shown in Fig. 2 corresponds to the vertical axis direction, horizontal axis direction, and diagonal axis direction of the face part, and the tube from the end of the rectangular frame to the joint in each axis direction. The axial height, that is, the height of the skirt, the wall thickness of the face near the rectangular frame, the radius of curvature of the outer surface, and the radius of curvature of the inner surface are all indicated by the same reference numerals that correspond to those in FIG. 2.

In the glass panel 1 shown in Fig. 3, the heights of the skirt part in each axis direction of the face part are CHV, CHH and
Similarly to CHD, the wall thicknesses t _V , t _H and t _D near the rectangular frame in each axis direction of the face part are CHVCHHCHD,
In addition, it is configured to have the relationship t _V t _H t _D.

In order to configure the height of the skirt portion in each axial direction of the glass panel and the wall thickness near the rectangular frame in each axial direction of the face portion as described above, the radius of curvature of the outer surface of the face portion in each axial direction R _V , R _H and R _D , the inner curvature radii R _V ′, R _H ′, and R _D ′ are R _V ＜R _H ＜R _D and R _V ′
It is effective to set <R _H ′<R _D ′.

By making the glass panel into the shape shown in Figure 3 above, the wall thickness at the upper end in the vertical axis direction of the screen, where the mechanical expansion stress due to atmospheric pressure is greatest, is sufficiently thick, resulting in significant mechanical strength. can be improved. Also, of the distance from the top of the outer frame of the face section to the joint between the glass panel and the funnel, a sufficient distance corresponding to the diagonal corner, which was a particular problem, is secured, so it is possible to make the wall thickness of this section sufficiently thin. A glass panel that is strong against impact can be made without significantly increasing the weight of the glass panel.

In the above explanation, all curvature radii are expressed as a single curvature radius, but in the present invention, one curvature radius, for example R _V , has a radius of curvature that gradually changes from the center to the periphery of the panel face. It goes without saying that this also includes the case of so-called compound radius of curvature. In such a case, for example, the value of the approximate average radius of curvature when the composite radius of curvature is approximately expanded into a series may be used as one radius of curvature in the present invention.

〔Effect of the invention〕

As described above, according to the present invention, a cathode ray tube having a glass panel with excellent mechanical strength can be provided.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view for explaining the envelope shape of a cathode ray tube, Fig. 2 is a schematic diagram showing a cross section of a conventional glass panel along vertical, horizontal, and diagonal axes, and Fig. 3 2 is a schematic diagram showing a cross section of a glass panel according to an embodiment of the present invention, corresponding to FIG. 2. FIG. 1...Glass panel, 1-2...Face part,
1-3...Skirt part, 2...Fannel, 3...
...Joint part, CHH...height of the skirt part in the vertical axis direction, CHV...height of the skirt part in the horizontal axis direction,
CHD...height of the skirt section in the diagonal axis direction, R _V ...
...The radius of curvature of the outer surface in the vertical axis direction of the face part,
R _V ′...Radius of curvature of the inner surface of the face in the vertical direction, R _H ...Radius of curvature of the outer surface of the face in the direction of the horizontal axis, R _H ′...Radius of inner curvature of the face in the direction of the horizontal axis, R _D ... ...Radius of curvature of the outer surface in the direction of the diagonal axis of the face part, R _D ′...Radius of curvature of the inner surface of the face part in the direction of the diagonal axis, t _V ...Thickness in the direction of the vertical axis near the rectangular frame of the face part, t _H ...Thickness in the horizontal axis direction near the rectangular frame of the face part, t _D ...Thickness in the diagonal axis direction near the rectangular frame of the face part.

Claims (1)

[Scope of Claims] 1. A glass panel comprising a curved face portion having a substantially rectangular shape and having a fluorescent screen on at least the inner surface, and a skirt portion extending in the tube axis direction from the end of the face portion; In a cathode ray tube comprising a funnel-shaped funnel joined to a skirt portion of the glass panel via a joint portion, vertical, horizontal and diagonal axes from the end of the face portion of the glass panel to the joint portion are provided. Let the height in the tube axis direction be CHV, CHH and CHD, respectively.
In addition, when the wall thicknesses near the ends of the face portion of the glass panel in the vertical axis direction, horizontal axis direction, and diagonal axis direction are respectively t _V , t _H and t _D , CHVCHHCHD, and t _V t _H t A cathode ray tube characterized by _{a D.} 2 The radius of curvature of the outer surface of the glass panel in the vertical axis direction, horizontal axis direction, and diagonal axis direction is R _V , R _H and R _{D , respectively, and the vertical axis direction, horizontal axis direction, and diagonal axis direction of the inner surface of the face portion are R V , R H and R D} , respectively. A patent claim characterized in that R _V <R _H <R D and R _V ′<R _H ′<R _{D ′} , where the radii of curvature in the directions are R _V ′, R _H ′, and R _D ′, respectively. The cathode ray tube according to item 1.