| 摘要 |
PURPOSE:To provide a cathode-ray tube which can correct not only the raster rotation caused by the component of the axial direction of the earth magnetism but also the rotation of the electron beam itself caused during the correction of the raster rotation. CONSTITUTION:A CRT1 is provided with a deflecting part 20 which extends from the picture surface side of an electromagnetic focusing part 10, from a neck 2 of the CRT1, to the funnel of the CRT1. A first annular coil 31 symmetrical about the axis (z) of the CRT1 is installed at the front end of the axis (z) of the deflecting part 20. The raster rotation caused by the earth magnetism of the first coil 31 can be corrected by feeding a current which produces a magnetic field extinguishing rhe z-axis component of the earth magnetism, that is to say, a current producing a magnetic field in the reverse direction to the earth magnetism. In addition, a second annular coil 32 symmetrical about the axis (z) is provided at a given position of the neck 2, for example, in the space formed between annular permanent magnets 11 and 12 of the focusing part 10 so as to correct the rotation of the beam itself (the tilt of a vertically long spot). |
