US4675891A
Expired / Lapsed
US
⏱️ 0.0 years remaining
X-ray apparatus with focus position control
Assignee: General Electric CGR SA
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Filing: 1985-06-25
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Granted: 1987-06-23
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Expires: 2005-06-25
Abstract
Abstract The invention relates to an X-ray apparatus with focus position control, the focus being formed on the anode of an X-ray tube with magnetic bearings. The X-ray apparatus comprises a focus position sensing device cooperating with electronic means associated with the magnetic bearings, in order to control the position of the focus by displacing a rotor under the action of the magnetic bearings.
Inventors
- 👤 Andre Plessis
- 👤 Jacques Leguen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:02
CPC Classifications
H; H05; H05G; H05G1/00; H05G1/08; H05G1/26; H01; H01J; H01J35/00; H01J35/02; H01J35/04; H01J35/08; H01J35/10; H01J35/101; H01J35/1017; H01J35/103; H01J35/24
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
151 words
An X-ray apparatus having focus position control, comprising: an X-ray tube having: (a) a rotary anode on which a focus is formed; (b) a rotor coupled in rotation with the rotary anode for rotating the anode about a longitudinal axis; (c) magnetic bearings for movably supporting the rotor; electronic means for controlling the magnetic bearings to move the rotor along the longitudinal axis; means for sensing the position of the focus for supplying a difference signal to the electronic means, the difference signal corresponding to a position variation of the focus along a control axis parallel to the longitudinal axis; wherein the difference signal is compared with a reference signal for controlling the magnetic bearings to move the rotor along the longitudinal axis in a direction opposite to the direction in which the position variation of the focus was affected, so as to control and stabilize the position of the focus.
Claim 2
Dependent Claim
151 words
An X-ray apparatus having focus position control, comprising: an X-ray tube having: (a) a rotary anode on which a focus is formed; (b) a rotor coupled in rotation with the rotary anode for rotating the anode about a longitudinal axis; (c) magnetic bearings for movably supporting the rotor; electronic means for controlling the magnetic bearings to move the rotor along the longitudinal axis; means for sensing the position of the focus for supplying a difference signal to the electronic means, the difference signal corresponding to a position variation of the focus along a control axis parallel to the longitudinal axis; wherein the difference signal is compared with a reference signal for controlling the magnetic bearings to move the rotor along the longitudinal axis in a direction opposite to the direction in which the position variation of the focus was affected, so as to control and stabilize the position of the focus.
Claim 3
Dependent Claim
32 words
An X-ray apparatus according to claim 1, wherein the electronic means comprises: means for comparing the difference signal and the reference signal to produce an error signal for controlling the magnetic bearings.
Claim 4
Dependent Claim
45 words
An X-ray apparatus according to claim 2, wherein the electronic means further comprises: a power supply for supplying the reference signal; wherein the reference signal is applied to a first input and the difference signal is applied to a second input of the comparing means.
Claim 5
Dependent Claim
62 words
An X-ray apparatus according to claim 2, further comprising: means for axially detecting the position of the rotor along the longitudinal axis and for supplying a signal corresponding to the detected rotor position; wherein the rotor position signal is applied as the reference signal to a first input and the difference signal is applied to a second input of the comparing means.
Claim 6
Dependent Claim
86 words
An X-ray apparatus according to claim 4, wherein the focus and the focus position sensing means correspond to a first measuring channel having a first coefficient; and wherein the axial rotor position detecting means, the electronic means, the magnetic bearings and the rotor correspond to a second measuring channel having a second coefficient, the absolute value of the ratio of the first coefficient to the second coefficient exceeding one; and wherein the coefficients are of opposite signs so as to overcome position variation of the focus.
Claim 7
Dependent Claim
83 words
An X-ray apparatus according to claim 4, wherein the focus and the focus position sensing means correspond to a first measuring channel having a first coefficient; and wherein the axial rotor position detecting means, the electronic means, the magnetic bearings and the rotor correspond to a second measuring channel having a second coefficient, the ratio of the first coefficient to the second coefficient exceeding one; and wherein the coefficients are of the same sign so as to undercompensate position variations of the focus.
Claim 8
Dependent Claim
30 words
An X-ray apparatus according to claim 2, wherein the electronic means comprises: amplifying means for receiving the difference signal and for applying a levelled difference signal to the comparing means.
Claim 9
Dependent Claim
36 words
An X-ray apparatus according to claim 3, wherein the electronic means comprises: a second power supply for supplying a replacement signal, in place of the difference signal, to the comparing means in the absence of X-rays.
Claim 10
Dependent Claim
42 words
An X-ray apparatus according to claim 1, wherein the focus position sensing means comprises: a pinhole camera; and two contiguous X-ray sensitive detector means, each of the detector means having an input plane on which an image of the focus is produced.
Claim 11
Dependent Claim
44 words
An X-ray apparatus according to claim 9, wherein the focus position sensing means further comprises: means for comparing signals outputted from the two detector means to supply a signal representative of the distribution of the image of the focus over the respective input planes.
Claim 12
Dependent Claim
44 words
An X-ray apparatus according to claim 9, wherein the focus position sensing means has a reference axis determined by the pinhole camera and the detector means, the reference axis passing through the focus at a point corresponding to an initial position of the focus.
Claim 13
Dependent Claim
29 words
An X-ray apparatus according to claim 1, further comprising: a member for calibrating the focus position sensing means, the focus position sensing means being coupled to the calibrating member.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-22 | 1990-12-22 | 1991-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-22 | 1994-12-22 | 1995-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-22 | 1998-12-22 | 1999-06-23 | $7700.00 | Window Closed / Lapsed |