| 摘要 |
A CATHODE RAY TUBE INCLUDES A VACUUM ENVELOPE (23) HAVING A SUBSTANTIALLY RECTANGULAR PANEL (20), A CYLINDRICAL NECK (22), AND A FUNNEL (21) CONNECTING THE PANEL AND THE NECK. A PHOSPHOR SCREEN (44) ARRANGED ON THE INNER SURFACE OF THE PANEL (20) GENERATES LUMINESCENCE UPON IMPINGEMENT OF ELECTRON BEAMS (46), ARE GENERATED BY AN ELECTRON GUN ASSEMBLY (47) DISPOSED IN THE NECK (22). IN ORDER TO CREATE A IMAGE VISIBLE THROUGH THE PANEL (20), A DEFLECTION YOKE (48) IS MOUNTED ON THE OUTER SURFACE OF THE FUNNEL (21) TO GENERATE A MAGNETIC FIELD IN THE FUNNEL, DEFLECT THE ELECTRON BEAMS (46), AND THEREBY SCAN THE PHOSPHOR SCREEN (44). ACCORDING TO THE PRESENT INVENTION, THE PORTION OF THE FUNNEL (21) OVER WHICH THE DEFLECTION YOKE (448) IS MOUNTED IS FORMED SUCH THAT THE POWER REQUIRED TO GENERATE A DEFLECTION FIELD CAPABLE OF SCANNING SUBSTANTIALLY THE ENTIRE PHOSPHOR SCREEN (44) MAY BE REDUCED. TO THIS END, THE FUNNEL (21) IS FORMED OVER A PREDETERMINED RANGE ALONG A FIRST AXIS COINCIDENT WITH THE AXIS OF SYMMETRY OF THE CYLINDRICAL NECK (22) SUCH THAT AT LEAST ONE CROSS SECTION OF THE INNER AND OUTER FUNNEL PERPENDICULAR TO THE FIRST AXIS HAS A NON-CIRCULAR SHAPE AND A MAXIMUM DIAMETER ALONG A DIRECTION OTHER THAN THOSE OF THE MAJOR AND MINOR AXES OF THE SUBSTANTIALLY RECTANGULAR PANEL (20). MOREOVER, WITHINTHIS PREDETERMINED RANGE, THE POINT ON THE FUNNELS CROSS SECTION THAT IS FURTHEST FROM THE FIRST AXIS IS NOT LOCATED ALONG THE DIRECTION OF THE PANELS DIAGONAL AXIS.FIGURE 6
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