Patent ID: 7046767

Claim:
An X-ray generating device, wherein an electron beam is made to hit one surface of a target to make X-rays be radiated from the other surface of said target, said X-ray generating device comprising: an electron beam generating means; and an electron lens forming means, including one magnetic pole positioned at said electron beam generating means side and the other magnetic pole positioned at said target side, and for making the electron beam converge by using the magnetic field generated by these magnetic poles, said one magnetic pole having a first opening from which the electron beam generated by said electron beam generating means is emitted, said other magnetic pole having a second opening into which the electron beam emitted from said first opening enters, and the value of the diameter of said second opening being greater than the value of the diameter of said first opening, wherein said other magnetic pole has a third opening that emits, towards said target, the electron beam that has entered into said second opening, the target being fixed in a position that covers one end of the third opening.