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Active matrix X-ray imaging array

  • US 5,962,856 A
  • Filed: 04/06/1998
  • Issued: 10/05/1999
  • Est. Priority Date: 04/28/1995
  • Status: Expired due to Term
First Claim
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1. An active matrix imager, comprising:

  • a) an array of thin film transistors disposed in a plurality of rows and columns, each of said transistors having a control terminal and a pair of signal terminals;

    b) a dielectric layer overlying each of said thin film transistors;

    c) scanning control circuit means having a plurality of control lines, respective ones of said control lines being connected to the control terminals of each of the thin film transistors in respective ones of said rows;

    d) read out circuit means having a plurality of data lines, respective ones of said data lines being connected to a first one of said pair of signal terminals of each of the thin film transistors in respective ones of said columns;

    e) a plurality of pixel electrodes respectively connected to a second one of said pair of signal terminals of each of the thin film transistors in said array of thin film transistors;

    f) a plurality of storage capacitors connected to respective ones of said pixel electrodes;

    g) a photoconductive layer overlying said plurality of pixel electrodes and said dielectric layer, wherein electron-hole pairs are created in response to exposing said photoconductive layer to radiation;

    h) a bias electrode overlying said photoconductive layer;

    i) first voltage means for establishing a high voltage difference between said bias electrode and respective ones of said pixel electrodes, whereby charges created by said electron-hole pairs are collected on respective ones of said pixel electrodes and stored on respective ones of said storage capacitors, the amount of said collected charges being proportional to intensity of said radiation exposure; and

    j) means overlying said first one of said pair of signal terminals of each of the thin film transistors in respective ones of said columns for establishing an electric field for repelling said charges in the vicinity of said first one of said pair of signal terminals toward said pixel electrodes, wherein said means overlying said first one of said pair of signal terminals of each of the thin film transistors further comprises a plurality of grid lines connected to a source of opposite polarity voltage to said bias electrode.

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