X-ray tube

• US 5,259,014 A
• Filed: 12/12/1991
• Issued: 11/02/1993
• Est. Priority Date: 01/08/1991
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Brettschneider, Horst
• Primary Examiner(s): Porta, David P.
• Application Number:
  US07/806,025
• Time in Patent Office: 691 Days
• Field of Search: 378/136, 378/137, 378/138, 378/114, 378/115, 378/134
• US Class Current: 378/138
• CPC Class Codes: H01J 35/066 Details of electron optical components, e.g. cathode cups
• CPC Class Codes: H01J 35/147 Spot size control
• CPC Class Codes: H01J 35/153 Spot position control

Abstract

An X-ray tube has a focal spot which can be varied in respect of position or size. A cathode has dimensions adapted to the variation of the focal spot, and between the cathode and the anode of the X-ray tube there is a grid arrangement which comprises a number of grid elements in one plane, which elements are electrically insulated from one another, and whose potential is independently controlled.

Claims

1. An X-ray tube for generating a variable focal spot, comprising:

a cathode whose dimensions are adapted for focal spot dimension variation, an anode, and a grid arrangement between the cathode and the anode of the X-ray tube, said grid arrangement comprising a plurality of coplanar grid elements, said grid elements being electrically insulated from one another and having respective potentials mutually independently controllable.

2. An X-ray tube as claimed in claim 1 wherein for the displacement of the focal spot in a direction, the grid arrangement comprises grid elements adjacently arranged in said displacement direction and adapted to be successively connected to a potential such that the electrons emitted by the cathode pass the grid at the area of the grid element receiving said potential.

3. An X-ray tube as claimed in claim 1 including means for constructing the anode and the cathode as a rotary-anode X-ray tube.

4. An X-ray tube as claimed in claim 2 including means for constructing the anode and the cathode as a rotary-anode X-ray tube.