| 摘要 |
PROBLEM TO BE SOLVED: To provide a distortion correcting device 31 of an X-ray image tube 11 capable of correcting the distortion automatically. SOLUTION: An external magnetic field m to intrude into an electronic lens region 23 from the exterior of the X-ray image tube 11 is detected by a magnetic field sensor 32. Based on the detection of the magnetic field sensor 32, the magnetic field to cancel the external magnetic field m is generated by a coil 33 arranged at an input face region 21 of the X-ray image tube 11, thereby removing the influence of the external magnetic field m and correcting distortion. The magnetic field sensor 32 is arranged in a region surrounded by a magnetic shield 20 of the X-ray image tube 11 and in the outer peripheral region of the electronic lens region 23 side separated from the input face region 21 of the X-ray image tube 11. The influence of the magnetic field generated by the coil 33 arranged on the input face region 21 side of the X-ray image tube 11 is reduced, and magnetic field sensor 32 detects the external magnetic field m which intrudes into the electronic lens region 23 with superior precision. COPYRIGHT: (C)2007,JPO&INPIT
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