| 摘要 |
<p>An X-ray tube comprising an anode having a target face which emits X-rays from an X-ray focus position by bombardment with an electron beam, a focusing electrode opposed to the target face and having a valley portion the farthest from the X-ray focus position, at least one inclined wall surface obliquely ascending from the valley portion toward the anode, and a cathode for emitting the electron beam disposed in the focusing groove and having a generally rectangular focusing groove, wherein the focusing groove has first and second corner portions bending from at least one end wall opposed to the end of the cathode toward two side walls in the longitudinal direction of the cathode, the first corner portion on the distal side from the valley portion is less bent than the second corner portion on the near side to the valley portion. With this constitution, the distortion of the X-ray focus of the X-ray tube is reduced.</p> |
