| 摘要 |
PROBLEM TO BE SOLVED: To provide a distortion correction device 21 for an X-ray image tube 11 in which the occurrence of hunting when correcting effect from outside magnetic field can be prevented, and the effect from the outside magnetic field can be corrected within a short time. SOLUTION: An outside magnetic field invading into the X-ray image tube 11 from the outside is detected by a magnetic field detecting part 22. A power source part 24 is controlled by a control part 25 and the electric current is made to flow from the power source part 24 to a coil 23 to make the coil 23 generate a magnetic field that negates the outside magnetic field. When the outside magnetic field detected by the magnetic field detecting part 22 is fluctuated exceeding a prescribed reference range of the magnetic field strength, control by the power source part 24 is corrected to be returned within the reference range. When the outside magnetic field detected by the magnetic field detecting part 22 is fluctuated within the prescribed reference range of the magnetic field strength, control by the power source part 24 is not corrected. The occurrence of hunting when correcting the influence of the outside magnetic field can be prevented, and fluctuations of the outside magnetic field can be converged within a short time. COPYRIGHT: (C)2007,JPO&INPIT
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