US 6,816,573 B2Granted

X-ray generating apparatus, X-ray imaging apparatus, and X-ray inspection system

AssigneeHamamatsu Photonics K.K.

InventorsMasayuki Hirano, Hiroki Kawakami

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Abstract

The voltage applied to a first grid electrode 71 of an X-ray tube 11 by a grid voltage control section 110 is controlled with reference to a predetermined negative voltage from a negative voltage generating section 112 when an object 5 to be inspected does not exist in an imaging area (irradiation area of an X-ray from an X-ray source 1) so that the pulse outputted from a pulse generator 105 is in its OFF state, and is controlled with reference to a reference positive voltage from a reference voltage generating section 115 when the object 5 to be inspected exists in the imaging area in the X-ray image intensifier 2 (irradiation area of the X-ray from the X-ray source 1) so that the pulse outputted from the pulse generator 105 is in its ON state, whereby both of the cutoff voltage and grid operating voltage are applied in a stable state.

Claims5

Dependent claims

An X-ray generating apparatus comprising:

an X-ray tube for generating, within a housing sealed into vacuum, an X-ray by focusing an electron emitted from a cathode into an anode target by way of a first grid electrode, a second grid electrode, and a focusing electrode;
grid voltage control means for controlling a grid voltage applied to said first grid electrode;
and
pulse generating means for generating a pulse which changes from an OFF state to an ON state and maintains said ON state for a predetermined period of time;
wherein said first grid electrode is disposed on the focusing electrode side of said cathode, whereas said second grid electrode is disposed on the focusing electrode side of said first grid electrode;
wherein said grid voltage control means has cathode current detecting means for detecting a cathode current and, in response to said pulse generated by said pulse generating means, applies a cutoff voltage to said first grid electrode when said pulse is in said OFF state so as to prevent said electron emitted from said cathode from reaching said anode target, and applies to said first grid electrode, in response to said pulse generated by said pulse generating means, a grid operating voltage adjusted such that said cathode current detected by said cathode current detecting means attains a predetermined value when said pulse is in said ON state;
wherein said cathode current detecting means has a cathode current detecting resistor, connected to said cathode, for detecting said cathode current;
and
wherein said grid voltage control means has:
an operational amplifier having one input terminal for inputting a voltage generated by said cathode current detecting resistor and the other input terminal for inputting a predetermined negative voltage or a reference voltage positive voltage;
and
a grid voltage control circuit for controlling, in response to an output from said operational amplifier, said grid voltage applied to said first grid electrode.

9 more elements

An X-ray imaging apparatus comprising imaging means for capturing an X-ray transmission image formed upon irradiating an object to be inspected with an X-ray generated by an X-ray generating apparatus;

wherein said X-ray generating apparatus comprises:
an X-ray tube for generating, within a housing sealed into vacuum, an X-ray by focusing an electron emitted from a cathode into an anode target by way of a first grid electrode, a second grid electrode, and a focusing electrode;
grid voltage control means for controlling a grid voltage applied to said first grid electrode;
and
pulse generating means for generating a pulse which changes from an OFF state to an ON state and maintains said ON state for a predetermined period of time;
wherein said grid voltage control means has cathode current detecting means for detecting a cathode current and, in response to said pulse generated by said pulse generating means, applies a cutoff voltage to said first grid electrode when said pulse is in said OFF state so as to prevent said electron emitted from said cathode from reaching said anode target, and applies to said first grid electrode, in response to said pulse generated by said pulse generating means, a grid operating voltage adjusted such that said cathode current detected by said cathode current detecting means attains a predetermined value when said pulse is in said ON state;
and
wherein said cathode current detecting means has a cathode current detecting resistor, connected to said cathode, for detecting said cathode current;
wherein said grid voltage control means has:
an operational amplifier having one input terminal for inputting a voltage generated by said cathode current detecting resistor and the other input terminal for inputting a predetermined negative voltage or a reference positive voltage;
and
a grid voltage control circuit for controlling, in response to an output from said operational amplifier, said grid voltage applied to said first grid electrode;
and
wherein said imaging means receives said pulse generated by said pulse generating means and captures said X-ray transmission image when said pulse is in said ON state.

11 more elements

An X-ray inspection system comprising an X-ray generating apparatus, an X-ray imaging apparatus having imaging means for capturing an X-ray transmission image formed upon irradiating an object to be inspected with an X-ray generated by said X-ray generating apparatus;

and object detecting means for detecting arrival of said object in an imaging area in said X-ray imaging apparatus;
wherein said X-ray generating apparatus comprises:
an X-ray tube for generating, within a housing sealed into vacuum, an X-ray by focusing an electron emitted from a cathode into an anode target by way of a first grid electrode, a second grid electrode, and a focusing electrode;
grid voltage control means for controlling a grid voltage applied to said first grid electrode;
and
pulse generating means for generating a pulse which changes from an OFF state to an ON state and maintains said ON state for a predetermined period of time;
wherein said grid voltage control means has cathode current detecting means for detecting a cathode current and, in response to said pulse generated by said pulse generating means, applies a cutoff voltage to said first grid electrode when said pulse is in said OFF state so as to prevent said electron emitted from said cathode from reaching said anode target, and applies to said first grid electrode, in response to said pulse generated by said pulse generating means, a grid operating voltage adjusted such that said cathode current detected by said cathode current detecting means attains a predetermined value when said pulse is in said ON state;
wherein said cathode current detecting means has a cathode current detecting resistor, connected to said cathode, for detecting said cathode current;
wherein said grid voltage control means has:
an operational amplifier having one input terminal for inputting a voltage generated by said cathode current detecting resistor and the other input terminal for inputting a predetermined negative voltage or a reference positive voltage;
and
a grid voltage control circuit for controlling, in response to an output from said operational amplifier, said grid voltage applied to said first grid electrode;
wherein said pulse generating means has trigger signal outputting means for outputting a trigger signal according to said detection of said object by said object detecting means and outputs said pulse when said trigger signal is outputted from said trigger signal outputting means;
and
wherein said imaging means receives said pulse outputted from the pulse generating means and captures said X-ray transmission image when said pulse is in said ON state.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/943,085Filed 31 Aug 2001 · continuation in part
Priority: JP P11-0542672 Mar 1999
Published: US 2002/0034279 A121 Mar 2002
Granted: 9 Nov 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G01N 23/04
By transmitting the radiation through the material: and forming images of the material
H01J 35/04
Details: electrodes ; Mutual position thereof; Constructional adaptations therefor
H05G 1/10
Electrical details: power supply arrangements for feeding the X-ray tube
H05G 1/30
Measuring, controlling or protecting: controlling