Method and apparatus for acquiring an X-ray image using a thin film transistor array

Claim 1

An X-ray image capture element, comprising: a first, electrically conductive backing layer; a second, photoconductive layer responsive to both actinic and X-ray radiation extending substantially over said backing layer, the photoconductor layer having a back surface in contact with said backing layer and a front surface opposite said back surface; a third, dielectric layer substantially transparent to both actinic and X-ray radiation, the dielectric layer also having a back surface and a front surface, the dielectric back surface extending substantially over and in contact with said front surface of the photoconductive layer; a plurality of discrete conductive outer microplates substantially transparent to both actinic and X-ray radiation, said outer microplates arranged on said front surface of the dielectric layer with a space between adjacent microplates, each of said outer microplates having dimensions coextensive with a minimum resolvable picture element; a first plurality of discrete conductive Xn address lines extending along the outer microplates; a second plurality of discrete conductive Yn sense lines extending along said outer microplates in a direction across said Xn address lines; and each outer microplate being connected to one adjacent of said plurality of the Xn address and Yn sense lines via at least one transistor.

Claim 10

A method for capturing a radiogram on an X-ray image capture element, comprising: a first, electrically conductive, backing layer; a second, photoconductive layer responsive to both actinic and X-ray radiation extending substantially over said backing layer; a third, dielectric layer substantially transparent to both actinic and X-ray radiation, the dielectric layer having a back surface extending substantially over and in contact with said photoconductive layer and a front surface; a plurality of discrete conductive outer microplates substantially transparent to both actinic and X-ray radiation, said microplates arranged on said front surface with a space between adjacent microplates, each of said microplates having dimensions coextensive with a minimum resolvable picture element, the microplates, dielectric layer, photoconductive layer and backing layer forming a plurality of microcapacitors; a first plurality of discrete conductive Xn address lines extending along the microplates; a second plurality of discrete conductive Yn sense lines extending along said microplates in a direction across said Xn address lines; and each microplate being connected to one adjacent of said plurality of said Xn and Yn lines via a transistor, the method comprising: (a) preventing actinic radiation from impinging on said element; (b) switching the pluralities of Xn and Yn lines to a first charging position and applying a bias voltage through the transistors simultaneously to all the microplates to develop an electric potential difference between said plurality of discrete conductive microplates and said backing layer; (c) impinging imagewise modulated X-ray radiation for a first time period onto the element; (d) after the first time period, stopping the applying of the bias voltage to trap in the microcapacitors electrical charges proportional to the intensity of the impinging radiation on the microplates; (e) switching the plurality of the Xn and Yn lines to a second readout position; (f) optionally exposing the element to uniform radiation for a second time period; (g) while exposing the element to actinic radiation, addressing one of said plurality of Xn lines with a trigger voltage to switch to a conductive state the transistors connecting the addressed Xn line to a subset of the microplates and to connect said subset of the microplates to the Yn lines; (h) sequentially detecting an output signal for each microplate connected to said plurality of Yn sense lines; and (i) repeating steps (g) and (h) for each of said plurality of Xn or Yn address lines until all signals from all microplates have been detected.

Claim 11

A method for capturing a radiogram on an X-ray image capture element, comprising: a first, electrically conductive, backing layer; a second, photoconductive layer responsive to both actinic and X-ray radiation extending substantially over said backing layer; a third, dielectric layer substantially transparent to both actinic and X-ray radiation, the dielectric layer having a back surface extending substantially over and in contact with said photoconductive layer and a front surface; a plurality of discrete conductive outer microplates substantially transparent to both actinic and X-ray radiation, said microplates arranged on said front surface with a space between adjacent microplates, each of said microplates having dimensions coextensive with a minimum resolvable picture element, the microplates, dielectric layer, photoconductive layer and backing layer forming a plurality of microcapacitors; a first plurality of discrete conductive Xn address lines extending along the microplates; a second plurality of discrete conductive Yn sense lines extending along said microplates in a direction across said Xn address lines; and each microplate being connected to one adjacent of said plurality of said Xn and Yn lines via a transistor, the method comprising: (a) preventing actinic radiation from impinging on said element; (b) switching the pluralities of Xn and Yn lines to a first charging position and applying a bias voltage through the transistors simultaneously to all the microplates to develop an electric potential difference between said plurality of discrete conductive microplates and said backing layer; (c) impinging imagewise modulated X-ray radiation for a first time period onto the element; (d) after the first time period, stopping the applying of the bias voltage to trap in the microcapacitors electrical charges proportional to the intensity of the impinging radiation on the microplates; (e) switching the plurality of the Xn and Yn lines to a second readout position; (f) optionally exposing the element to uniform radiation for a second time period; (g) while exposing the element to actinic radiation, addressing one of said plurality of Xn lines with a trigger voltage to switch to a conductive state the transistors connecting the addressed Xn line to a subset of the microplates and to connect said subset of the microplates to the Yn lines; (h) sequentially detecting an output signal for each microplate connected to said plurality of Yn sense lines; and (i) repeating steps (g) and (h) for each of said plurality of Xn or Yn address lines until all signals from all microplates have been detected.