US 5,929,449 A · Flat panel detector for radiation imaging with reduced electronic noise

Abstract

A thin-film, flat panel, pixelated detector array serving as a real-time digital imager and dosimeter for diagnostic or mega-voltage X rays or gamma rays, including a plurality of photodiodes (30) made of hydrogenated amorphous silicon arrayed in columns and rows upon a glass substrate (12). Each photodiode (30) is connected to a thin film field effect transistor (52) also located upon the glass or quartz substrate (12). Upper and lower metal contacts (38, 22) are located below and above the photodiodes (30) to provide the photodiodes (30) with a reverse bias. The capacitance of each photodiode (30) when multiplied by the resistance of the field effect transistor (52) to which it is connected yields an RC time constant sufficiently small to allow fluoroscopic or radiographic imaging in real time.

Claims18

Dependent claims

A flat panel detector for radiation imaging comprising:

an array of pixels arranged in rows and columns, each of said pixels including a pixel electrode to store a charge proportional to the exposure of said pixel to radiation;
a radiation transducer over said array to be exposed to incident radiation;
a plurality of source lines, each interconnecting the pixels in individual ones of one of the rows or columns of said array;
a plurality of gate lines, each interconnecting the pixels in individual ones of the other of the rows or columns of said array, said source and gate lines crossing one another to define a plurality of overlapping nodes;
and
shielding means to shield said gate lines from said source lines at said overlapping nodes to reduce parasitic capacitance at the overlapping nodes.

3 more elements

A flat panel detector for radiation imaging comprising:

a radiation transducer including a radiation conversion layer and an electrode on one side of said radiation conversion layer;
an array of pixels arranged in rows and columns on the other side of said radiation conversion layer, each of said pixels including a pixel electrode to accumulate charge as a result of hole drift in said radiation conversion layer occurring upon exposure of said radiation transducer to radiation and when said electrode is biased;
a plurality of source lines upon which charges accumulated by said pixels can be sensed, each of said source lines connecting the pixels of individual ones of one of said rows or columns;
a plurality of gate lines upon which gating signals are supplied to allow accumulated charges to be sensed, each of said gate lines connecting the pixels of individual ones of the other of said rows or columns;
and
shielding means to shield said gate lines from said source lines at overlapping points thereof to reduce parasitic capacitance at said overlapping points.

3 more elements

Dependencies are inferred from the claim text.

Flat panel detector for radiation imaging with reduced electronic noise

Life of this patent

Flat panel detector for radiation imaging with reduced electronic noise

Life of this patent

Abstract

Claims18