Colour picture tube with improved shielding
AssigneeMT Picture Display Germany GmbH
InventorsKonrad Leutz, Rolf Reidinger
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Abstract
The present invention relates to a colour picture tube and to a manufacturing method for a colour picture tube. The colour picture tube includes a shadow mask which is secured to a mask frame. In order to improve the shielding effect, a shielding plate, which shields external magnetic fields, is secured to at least one longitudinal bar of the mask frame. By means of such a shielding plate, the picture quality of a colour picture tube can be improved and the manufacturing efforts can be simplified in comparison with conventional colour picture tubes.
Claims29
A colour picture tube comprising an essentially rectangular shadow mask, a mask frame composed of transverse bars and longitudinal bars and supporting said shadow mask, a shielding cap mounted on said mask frame, and a shielding plate secured to a longitudinal bar of the mask frame and covering at least part of the outer side of said longitudinal bar.
A manufacturing method for a colour picture tube comprising a glass body, which is composed of a screen tray and a cone, said method comprising the steps of:
- producing a mask frame from transverse bars and longitudinal bars,
- inserting a mask into the mask frame, said mask and mask frame defining together a mask/frame combination,
- inserting the mask/frame combination into the screen tray,
- applying a luminescent layer to the inner side of the screen,
- fastening a shielding cap to the mask frame, and
- connecting the screen tray and the cone,
- wherein a shielding plate is mounted on at least one longitudinal bar of the mask frame prior to inserting the mask/frame combination into the screen tray.
Dependencies are inferred from the claim text.