Patent ID: 6333969
Filing Date: 2001-12-25
Classification: H01J

Abstract:
An X-ray tube comprising:an anode having a target surface radiating X-rays from a position of an X-ray focal spot by impingement of an electron beam,a focusing electrode having a bottom portion positioned facing said target surface of the anode and most remote from said X-ray focal spot, at least one inclined wall surface obliquely ascending from said bottom portion in the direction of said anode, and a substantially rectangular focusing recess formed at said inclined wall surface, anda cathode positioned in said focusing recess of the focusing electrode for emitting an electron beam, characterized in thatsaid focusing recess has first and second corners which are rounded from at least one end wall facing the end of said cathode to two side walls along the direction of the longer side of said cathode, and in thatthe first corner located remote from said bottom portion is gentler than the second corner located adjacent to said bottom portion, with reference to curving degree.