Positioning apparatus for an electron beam

Patent metadata

Field	Value
Publication number	US-9748067-B2
Application number	US-201514709068-A
Country	US
Kind code	B2
Filing date	May 11, 2015
Priority date	May 20, 2014
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A positioning apparatus is provided for an electron beam of an electron tube, the apparatus including a first DC voltage circuit having a high potential difference and a second DC voltage circuit having a smaller potential difference, having in each case a first potential level and a second potential level, and a deflection module, which has two inputs and at least one deflection coil, wherein the at least one deflection coil is connected between the two inputs of the deflection module.

First claim

The invention claimed is:

1. A positioning apparatus for an electron beam of an electron tube, the positioning apparatus comprising:
a first DC voltage circuit comprising a high potential difference, a first potential level, and a second potential level;
a second DC voltage circuit comprising a smaller potential difference, a first potential level, and a second potential level, wherein a ratio of a voltage drop across the second DC voltage circuit contributes to a voltage drop across the first DC voltage circuit by up to 1:4; and
a deflection module comprising two inputs and at least one deflection coil, the at least one deflection coil connected between the two inputs,
wherein the first potential level of the first DC voltage circuit is connected switchably to one of the two inputs of the deflection module to provide a first switching path, and the second potential level of the first DC voltage circuit is connected to a second of the two inputs of the deflection module, and
wherein the first potential level of the second DC voltage circuit is connected switchably to one of the two inputs of the deflection module to provide a second switching path, which is switchable separately from the first switching path, and the second potential level of the second DC voltage circuit is connected to a second of the two inputs of the deflection module.

2. The positioning apparatus as claimed in claim 1 , wherein the deflection module comprises a full bridge comprising a first input terminal, a second input terminal, a first output terminal, and a second output terminal,
wherein both the first input terminal and the second input terminal are connected to one of the two inputs of the deflection module, and
wherein the at least one deflection coil is connected between the first output terminal and the second output terminal.

3. The positioning apparatus as claimed in claim 2 , wherein the first switching path and the second switching path end are at a same input of the deflection module.

4. The positioning apparatus as claimed in claim 3 , wherein the first switching path comprises a first semiconductor switch, and the second switching path comprises a second semiconductor switch.

5. The positioning apparatus as claimed in claim 4 , wherein a first diode is connected back-to-back in parallel with the first switch, a second diode is connected in parallel with the second switch, or the first diode is connected back-to-back in parallel with the first switch and the second diode is connected in parallel with the second switch.

6. The positioning apparatus as claimed in claim 5 , wherein a coil and a diode connected back-to-back in parallel are connected in the first switching path.

7. The positioning apparatus as claimed in claim 1 , wherein the first switching path and the second switching path end are at a same input of the deflection module.

8. The positioning apparatus as claimed in claim 1 , wherein the first switching path comprises a first semiconductor switch, and the second switching path comprises a second semiconductor switch.

9. The positioning apparatus as claimed in claim 8 , wherein a first diode is connected back-to-back in parallel with the first switch, a second diode is connected in parallel with the second switch, or the first diode is connected back-to-back in parallel with the first switch and the second diode is connected in parallel with the second switch.

10. The positioning apparatus as claimed in claim 1 , wherein a coil and a diode connected back-to-back in parallel are connected in the first switching path.

11. The positioning apparatus as claimed in claim 1 , wherein a current measuring device is connected on an input side, an output side, or the input side and the output side of the at least one deflection coil.

12. A method for actuating, by pulse width modulation, a positioning apparatus for an electron beam in an electron tube, the positioning apparatus comprising (1) a first DC voltage circuit comprising a high potential difference, a first potential level, and a second potential level, (2) a second DC voltage circuit comprising a smaller potential difference, a first potential level, and a second potential level, and (3) a deflection module comprising two inputs and at least one deflection coil, the at least one deflection coil connected between the two inputs, the method comprising:
connecting, in a first cycle, the first potential level of the first DC voltage circuit to the at least one deflection coil by switching until a first threshold value for the current is exceeded in the deflection coil;
connecting, in a plurality of further cycles, the first potential level of the second DC voltage circuit by switching to the at least one deflection coil until a second threshold value for the current is exceeded in the deflection coil; and
determining a respective duty factor of a switching time for exceeding the first threshold value in the first cycle and for exceeding the second threshold value in the plurality of further cycles using a number of characteristic parameters of the at least one deflection coil.

13. The method as claimed in claim 12 , further comprising measuring a current flowing through the at least one deflection coil with a current measuring device connected on an input side, an output side, or the input side and the output side of the at least one deflection coil;
comparing the measured current with the first threshold value in the first cycle and with the second threshold value in a plurality of further cycles; and
determining the respective duty factor of the switching time using the compared measured current.

14. An X-ray tube comprising:
an electron source for generating an electron beam,
a positioning apparatus focusing the electron beam, the positioning apparatus comprising: (1) a first DC voltage circuit comprising a high potential difference, a first potential level, and a second potential level; (2) a second DC voltage circuit comprising a smaller potential difference, a first potential level, and a second potential level, wherein a ratio of a voltage drop across the second DC voltage circuit contributes to a voltage drop across the first DC voltage circuit by up to 1:4; and (3) a deflection module comprising two inputs and at least one deflection coil, the at least one deflection coil connected between the two inputs; and
a control apparatus configured to: (1) connect, in a first cycle, the first potential level of the first DC voltage circuit to the at least one deflection coil by switching until a first threshold value for the current is exceeded in the deflection coil; and (2) connect, in a plurality of further cycles, the first potential level of the second DC voltage circuit by switching to the at least one deflection coil until a second threshold value for the current is exceeded in the deflection coil.

Assignees

• Berk Jan
• Weidinger Thomas
• Siemens Ag

Inventors

• Berk Jan
• Weidinger Thomas

Classifications

• H01J29/70

  Arrangements for deflecting ray or beam {(H01J29/467, H01J29/525 take precedence)} · CPC title

• H01J3/26

  Arrangements for deflecting ray or beam · CPC title

• H05G1/66

  Circuit arrangements for X-ray tubes with target movable relatively to the anode · CPC title

• H01J35/14

  Arrangements for concentrating, focusing, or directing the cathode ray · CPC title

• H01J29/98 Primary

  Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for · CPC title