High resolution flat panel for radiation imaging

• US 20020053946A1
• Filed: 03/15/2001
• Published: 05/09/2002
• Est. Priority Date: 11/02/1998
• Status: Active Grant

• Current Assignee: Xylon LLC (Intellectual Ventures LLC)
• Original Assignee: iFire Technology Inc.
• Inventors: Huang, Zhong Shou
• Granted Patent: US 6,486,470 B2
• Time in Patent Office: Days
• US Class Current: 330/127
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 3/22 using controlled light sources

Abstract

A high resolution flat panel for radiation imaging includes an array of pixels arranged in rows and columns. Gate lines interconnect the pixels of the rows while source lines interconnect the pixels of the columns. Gate Driver circuits provide gate pulses to successive gate lines in response to input from a control circuit to select pixels on a row-by-row basis. The source lines lead to charge amplifiers that sense signal charges stored by the pixels when the pixels are selected. At least one pair of adjacent pixels in each row shares a source line. Gating of the pairs of pixels in the rows that share a source line is controlled by control logic to ensure that signal charges stored by only one of those pixels is applied to a shared source line at a time. This reduces the number of charge amplifiers in the flat panel while maintaining high resolution.

Claims

1. A flat panel for radiation imaging comprising:

a radiation transducer to be exposed to incident radiation;

an array of pixels on one side of said radiation transducer, each of said pixels including a storage capacitor to store signal charge proportional to the exposure of said radiation transducer to radiation in the vicinity of said pixels;

a plurality of gate lines interconnecting the rows of pixels in said array, said gate lines receiving gate pulses to allow said pixels to be selected on a row-by-row basis;

a plurality of source lines interconnecting the columns of pixels in said array to allow signal charges held by the storage capacitors of said selected pixels to be sensed, at least one pair of adjacent pixels in each row sharing a source line; and

control means to control selection of the pixels sharing a source line so that the signal charge stored by the storage capacitor of only one pixel of each pair can be sensed by way of a shared source line at a time when said row of pixels is selected.

2. A flat panel as defined in claim 1 wherein multiple pairs of adjacent pixels in each row share source lines.

3. A flat panel as defined in claim 2 further including refresh means to refresh the storage capacitors of said pixels after the signal charges held thereby have been sensed.

4. A flat panel as defined in claim 3 wherein the pixels are positioned on opposite sides of said pairs of adjacent pixels are positioned on opposite sides of said shared source line.

5. A flat panel as defined in claim 4 wherein said control means biases one pixel of each pair of pixels sharing source lines in a manner to allow said one pixel to be selected in response to a first portion of a gate pulse and then biases the other pixel of each pair of pixels sharing said source lines in a manner to allow said other pixel to be selected in response to the remaining portion of said gate pulse.

6. A flat panel as defined in claim 5 wherein said control means includes control lines interconnecting columns of pixels in said array and a pair of busses, each of said busses being connectable to a positive potential voltage source or to ground by way of a switch, the control lines interconnecting adjacent columns of pixels sharing a source line being connected to different busses, said switches being controlled so that one of said busses biases said one pixels of said pairs of pixels during said first portion of said gate pulse and so that the other of said busses biases said other pixels of said pairs of pixels during said remaining portion of said gate pulse.

7. A flat panel as defined in claim 5 wherein each of said pixels includes an amplifier to amplify signal charge held by said storage capacitors when being sensed by way of said source lines.

8. A flat panel as defined in claim 7 further including a compensation circuit to offset dc bias applied to said amplified signal charges by said amplifiers.

9. A flat panel as defined in claim 3 wherein said refresh means refreshes said storage capacitors of a previous row of pixels during selection of a following row of pixels.

10. A flat panel as defined in claim 3 wherein said refresh means refreshes said storage capacitors of all of said pixels after all rows of said pixels have been selected.

11. A flat panel as defined in claim 2 wherein said control means biases one pixel of said pairs of pixels sharing a source line in a manner to inhibit said one pixels from being selected during a first gate pulse and then biases said one pixels in a manner to allow said one pixels to be selected in response to a second gate pulse applied on the same gate line.

12. A flat panel as defined in claim 11 wherein said first gate pulses are applied to each of said gate lines prior to applying said second gate pulses to said gate lines.

13. A flat panel as defined in claim 12 wherein said control means includes control lines interconnecting alternate columns of pixels in said array and a buss, said buss being connectable between a low potential voltage node and a high potential voltage node by way of a switch, said switch being controlled so that said buss is connected to said low potential voltage node during said first gate pulses to inhibit selection of said one pixels and so that said buss is connected to said high potential voltage node during said second gate pulses to permit selection of said one pixels.

14. A flat panel as defined in claim 13 wherein the pixels of said pairs of adjacent pixels are positioned on opposite sides of said shared source line.

15. A flat panel as defined in claim 13 wherein the pixels of said pairs of adjacent pixels are positioned on the same side of said shared source line, one pixel of said pairs being connected directly to said source line and the other pixel of said pairs being connected to said source line through said one pixels.

17. A compensation circuit as defined in claim 16 wherein said switch means is in the form of a transistor switch.

18. A compensation circuit as defined in claim 17 wherein the magnitude of said potential voltage source is approximately equal to the magnitude of the amplified signal charge that is applied to a source line by a selected pixel which is located in a dark region of a radiation image.

16. A compensation circuit for use in a high resolution amplified flat panel for radiation imaging comprising:

an amplifier having an input terminal to receive amplified signal charge output on a source line by a selected pixel of said flat panel in response to a gate pulse, said amplified signal charge having a dc bias; and

switch means to connect said input terminal to a potential voltage source when said amplified charge is received, said potential voltage source having a magnitude substantially the same as said dc bias but opposite in polarity to offset said dc bias.