Facsimile and static presentation processing – Facsimile – Recording apparatus
Patent
1985-04-18
1988-01-19
Coles, Sr., Edward L.
Facsimile and static presentation processing
Facsimile
Recording apparatus
358247, 358248, 313477R, H04M 565
Patent
active
047207485
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
Technical Field
This invention relates to a cathode ray tube and more particularly relates to improvements of the panel thereof.
BACKGROUND ART
A panel for use in a square type cathode ray tube, for example, a cylindrical panel 1 of FIG. 1 and a spherical panel 2 of FIG. 2 are each formed of face portions 4 which are respectively formed as cylindrical and spherical curved surfaces and skirt portions 5. As shown in FIG. 3, such panel is a molded product that is provided by filling a melted glass 9 into a metal mold formed of a bottom 7 and a shell ring 8 and then pressing the melted glass 9 by a plunger 10. In accordance with the shape of the connected portion between the bottom 7 and the shell ring 8, the molded panel is given with a mold match line 3 which is a ridge line taking the form of gentle convexity. As shown in FIGS. 1 and 2, the mold match line 3 of the prior art panel is a straight line which runs in parallel to an end surface 11 thereof connected with a funnel portion. After this panel is assembled with the funnel portion to thereby construct the cathode ray tube, a tension band 16 is wound around the mold match line 3, whereby to reinforce the implosion protection of the cathode ray tube. The tension by the tension band 16 causes a compression force within the surface of the face portion 4 and produces a stress against the external force. However, when the tension band 16 is wound around the prior art panel, a tension F thereof is concentrated on the mold match line 3 of straight line shape. As a result, as shown in FIG. 5, at the corner portion where the mold match line 3 and the face portion 4 are close to each other, the tension F is transmitted to the face portion 4, while at central regions 12, 14 and 13 of the side portions of the face portion 4 remote from the mold match line 3 with large distances of ha, hb and hc, the tension F is not effectively transmitted to the face portion as shown in FIG. 4 so that the stresses caused by high atmospheric pressure and impact force can not be reduced so much. Particularly, when as shown in FIGS. 1 and 2, the tension band 16 has a uniform width over the entire periphery of the panel and the both upper and lower sides thereof are made in parallel to each other, the above-described problem exists in a standpoint for reinforcing implosion protection of the cathode ray tube.
In view of the above-described aspect, this invention is to provide a cathode ray tube in which the tension by a tension band over a mold match line can effectively be transmitted to the entire periphery of a face portion of a panel so that a resistance of the face portion against an external force can be increased to thereby increase the implosion protection.
DISCLOSURE OF INVENTION
The present invention relates to a cathode ray tube having a panel formed of a face portion which is formed as a curved surface and a skirt portion, wherein a mold match line of the panel is formed so as to be substantially matched with the boundary between the face portion and the skirt portion and in which a tension band for implosion protection is wound around the mold match line.
Further, in the above-described cathode ray tube of this invention, the tension band wound over the mold match line of the panel has the shape so as to be substantially matched with the boundary between the face portion and the skirt portion.
According to the above-described cathode ray tube, the tension by the tension band around the mold match line of the panel can effectively be transmitted to the entire periphery of the face portion, thus increasing the implosion protection of the cathode ray tube.
BRIEF DESCRIPTION OF DRAWINGS
FIGS. 1 and 2 are respectively perspective views illustrating the states that prior art tension bands are wound around a prior art cylindrical panel and spherical panel respectively;
FIG. 3 is a cross-sectional view showing a method for manufacturing a panel;
FIGS. 4 and 5 are cross-sectional views illustrating the way of how the tension by the tension band is applied t
REFERENCES:
patent: 3220593 (1965-11-01), Powell et al.
patent: 3730990 (1973-05-01), Miyata et al.
Hamanaka Akira
Omae Kazuo
Sumiyoshi Hiroji
Watanabe Yuzuru
Coles Sr. Edward L.
Sony Corporation
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