Patent EP0096843A1 successfully refreshed from Google Patents.
EP0096843A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
X-ray diagnostic apparatus
Assignee: Toshiba Corp
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Filing: 1983-06-08
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Granted: —
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Expires: 2003-06-08
Abstract
Abstract A falling load type X-ray diagnostic apparatus comprises a low voltage power source (60), AC-DC converting means (30) connected to the low voltage power source (60) so as to apply a rectified low DC voltage, chopping means (34) connected to the AC-DC converting means (30) and chopping said DC voltage into a low AC voltage, high voltage applying means (37, 38) for transforming said low AC voltage into a high AC voltage, said high AC voltage being applied as a tube voltage to an X-ray tube (25) from which X-rays are irradiated toward an object to be examined, means (39) for controlling a filament heating power of the X-ray tube, programming means (31, 40) for supplying a control signal to said filament heating control means (39) so as to reduce the emission current of said X-ray tube (25) during the irradiation, and chopper control means (32, 33) for controlling the chopping ratio of said chopping means (34) by evaluating said rectified DC voltage with a present tube voltage generated in said programming means (31), said programming means (31, 40) compensating said tube voltage by receiving said control signal in such a manner that said tube voltage is maintained substantially constant during the irradiation by varying said preset tube voltage so as to control the chopping ratio based upon the reduction of the filament heating power for the X-ray tube.
Inventors
- 👤 Masataka C/O Toshiba Medical Systems Arita
- 👤 Mitsuyoshi Matsubara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 18:24
CPC Classifications
H; H05; H05G; H05G1/00; H05G1/08; H05G1/26; H05G1/30; H05G1/46; H05G1/32; H05G1/34
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
226 words
An X-ray diagnostic apparatus comprising: a low voltage power source (60); AC-DC converting means (30) connected to the low voltage power source (60) so as to apply a rectified low DC voltage; chopping means (34) connected to the AC-DC converting means (30) and chopping said DC voltage into a low AC voltage; high voltage applying means (37, 38) for transforming said low AC voltage into a high AC voltage, said high AC voltage being applied as a tube voltage to an X-ray tube (25) from which X-rays are irradiated toward an object to be examined; means (39) for controlling a filament heating power of the X-ray tube; programming means (31, 40) for supplying a control signal to said filament heating control means (39) so as to reduce the emission current of said X-ray tube (25) during the irradiation; and chopper control means (32, 33) for controlling the chopping ratio of said chopping means (34) by evaluating said rectified DC voltage with a preset tube voltage generated in said programming means (31); said programming means (31, 40) compensating said tube voltage by receiving said control signal in such a manner that said tube voltage is maintained substantially constant during the irradiation by varying said preset tube voltage so as to control the chopping ratio based upon the reduction of the filament heating power for the X-ray tube.
Claim 2
Dependent Claim
226 words
An X-ray diagnostic apparatus comprising: a low voltage power source (60); AC-DC converting means (30) connected to the low voltage power source (60) so as to apply a rectified low DC voltage; chopping means (34) connected to the AC-DC converting means (30) and chopping said DC voltage into a low AC voltage; high voltage applying means (37, 38) for transforming said low AC voltage into a high AC voltage, said high AC voltage being applied as a tube voltage to an X-ray tube (25) from which X-rays are irradiated toward an object to be examined; means (39) for controlling a filament heating power of the X-ray tube; programming means (31, 40) for supplying a control signal to said filament heating control means (39) so as to reduce the emission current of said X-ray tube (25) during the irradiation; and chopper control means (32, 33) for controlling the chopping ratio of said chopping means (34) by evaluating said rectified DC voltage with a preset tube voltage generated in said programming means (31); said programming means (31, 40) compensating said tube voltage by receiving said control signal in such a manner that said tube voltage is maintained substantially constant during the irradiation by varying said preset tube voltage so as to control the chopping ratio based upon the reduction of the filament heating power for the X-ray tube.
Claim 3
Dependent Claim
199 words
An X-ray diagnostic apparatus as claimed in Claim 1, characterized in that said filament heating control means (39) comprises: second AC-DC converting means (41) connected to said low voltage power source (60) so as to apply a second rectified low DC voltage; second chopping means (43) connected to said second AC-DC converting means (41) and chopping said DC voltage into a second low voltage; filament power supply means (46, 47) for transforming said second AC voltage into a desired filament heating voltage of said X-ray tube; tube current selection means (51) including a selectable time constant circuit (R, Cl to Cn) and connected to receive said control signal from said programming means (31, 40), whereby a desired time constant is selected by said control signal; tube current level setting means (52) connected to said tube current selection means (51) so as to generate a tube current level setting signal; and second chopper control means for controlling the chopping ratio of said second chopping means (50) based upon said tube current level setting signal in such a manner that the filament heating power is reduced during the irradiation in accordance with said control signal from said programming means (31, 40).
Claim 4
Dependent Claim
72 words
An X-ray diagnostic apparatus as claimed in Claim 1 further comprising: means (35) for filtering said chopped low voltage from said chopping means (34); and DC-AC converting means (36) for converting said filtered chopped voltage into a second low AC voltage, a frequency of which is considerably higher than that of said low voltage power source (60), said second low AC voltage being applied to said high voltage applying means (37, 38).
Claim 5
Dependent Claim
72 words
An X-ray diagnostic apparatus as claimed in Claim 2 further comprising: means for filtering said chopped low voltage from said second chopping means (43); and DC-AC converting means (45) for converting said filtered chopped voltage into a second low AC voltage, a frequency of which is considerably higher than that of said low voltage power source (60), said second low AC voltage being applied to said filament power supply means (46, 47).
Claim 6
Dependent Claim
93 words
An X-ray diagnostic apparatus as claimed in Claim 1 further comprising: means (27) for detecting an X-ray which has penetrated through said object (26) to be examined and for producing a radiation signal in proportion to the detected X-ray dosage; and means (29) for comparing said exposure signal with a preset darkening level signal generated in said programming means, said comparing means being connected to control said chopper control means (32, 33) so as to interrupt a function of said chopping means (34) when said radiation signal level reaches said preset darkening level.
References Cited (Backward Citations)
DE2826455A1
Cited
GB2005878A
Cited
US4167670A
Cited
FR2440136A1
Cited
WO1982000397A1
Cited
EP0047957A1
Cited
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