| 摘要 |
PURPOSE:To provide good focusing performance of a color picture tube, by improving accuracy of the loading position of the limiting aperture unit in the focus electrode, and by solving the problem of the drop in the focusing voltage caused by the increase in the leakage current of the focus electrode due to the trimmed electron beam. CONSTITUTION:The limiting aperture unit 2 loaded within the focus electrode 4 through a ceramic support 1 is disposed so that each aperture is in alignment with the axis of each of the electron beams arranged in an in-line configuration. The ceramic support 1 is provided with the stepped holes 1a, 1b disposed in accordance with the interval between the electron beams, wherein the height h of the support and the depth l of the hole 1a may be adapted so that a suitable portion of the electron beam is trimmed by the limiting aperture 2 in accordance with the divergence angle of the electron beam. The limiting aperture unit 2 is automatically loaded in place with good accuracy within the focus electrode 4 since the unit is controlled by the preset dimensional accuracy provided in the ceramic support 1. Incidentally, in order to fix the ceramic support 1 within the focus electrode 4, a stopper 3 may be inserted therein and (the stopper 3 may be) welded to the focus electrode 4. |
