Hybrid active matrix flat panel detector system and method

Patent metadata

Field	Value
Publication number	US-11504079-B2
Application number	US-201716464888-A
Country	US
Kind code	B2
Filing date	Nov 30, 2017
Priority date	Nov 30, 2016
Publication date	Nov 22, 2022
Grant date	Nov 22, 2022

Abstract

A hybrid radiation imaging sensor includes a low x-ray attenuating substrate, a photoconductor disposed over the substrate, and a scintillator disposed over the photoconductor. By combining direct x-ray conversion to electron-hole pairs in the photo-conductor with indirect conversion of x-rays downstream of the photoconductor within the scintillator, improved x-ray imaging can be attained through an electronic readout located upstream of both the photoconductor and the scintillator without the need for excessive x-ray dosing.

First claim

What is claimed is:

1. A radiation imaging sensor, comprising:
a low x-ray attenuating substrate;
a photoconductive element disposed over the substrate;
a scintillator disposed over the photoconductive element;
a photoelectric conversion layer disposed between the photoconductive element and the scintillator, wherein the photoelectric conversion layer comprises tellurium-doped a-Se, cadmium selenide or cadmium sulfide, wherein the photoconductive element is disposed between the substrate and the photoelectric conversion layer; and
a charge blocking layer between the photoelectric conversion layer and the scintillator, wherein an effective electron-hole pair (EHP) creation energy (W±) of the scintillator is substantially equal to an effective electron-hole pair (EHP) creation energy (W±) of the photoconductive element.

2. The radiation imaging sensor of claim 1 , wherein the substrate is a flexible substrate.

3. The radiation imaging sensor of claim 1 , further comprising a charge blocking layer between the substrate and the photoconductive element.

4. The radiation imaging sensor of claim 1 , further comprising a pixel electrode array between the substrate and the photoconductive element.

5. The radiation imaging sensor of claim 1 , further comprising a transparent conductive electrode between the photoconductive element and the scintillator.

6. A radiation imaging sensor, comprising, from bottom to top:
a low x-ray attenuating substrate;
a pixel electrode array comprising a plurality of pixel electrodes;
a first charge blocking layer;
a photoconductive element;
a photoelectric conversion layer, wherein the photoelectric conversion layer comprises tellurium-doped a-Se, cadmium selenide or cadmium sulfide;
a second charge blocking layer;
a transparent conductive electrode; and
a scintillator optically coupled to the photoconductive element, wherein the photoelectric conversion layer is between the photoconductive element and the scintillator.

7. The radiation imaging sensor of claim 6 , further comprising a thin film transistor and a storage capacitor in electrical communication with each of the plurality of pixel electrodes.

8. The radiation imaging sensor of claim 6 , wherein the photoconductive element comprises a material selected from the group consisting of amorphous selenium, cadmium telluride, lead iodide, lead (II) oxide, mercuric iodide, lead zirconate titanate and barium strontium titanate, and the scintillator comprises a material selected from the group consisting of cesium oxide, bismuth germinate, lutetium orthosilicate, lutetium yttrium orthosilicate, calcium tungstate, thallium-doped cesium iodide, terbium-doped gadolinium oxysulfide, a barium fluorohalide and a scintillating glass.

9. The radiation imaging sensor of claim 6 , further comprising a buffer layer between the photoconductive element and the photoelectric conversion layer.

10. A method for imaging x-ray radiation, comprising:
exposing a radiation imaging sensor comprising a photoconductive element and a scintillator to x-ray radiation;
directly generating charge carriers within the photoconductive element in response to absorption of a first portion of the radiation by the photoconductive element, wherein a second portion of the radiation passes through the photoconductive element;
generating optical photons within the scintillator in response to absorption of the second portion of the radiation by the scintillator; and
indirectly generating charge carriers within the photoconductive element in response to absorption of the optical photons by the photoconductive element.

11. The method of claim 10 , wherein the x-ray radiation enters the sensor through a low x-ray attenuating substrate.

12. The method of claim 11 , further comprising forming a charge pattern on a pixel electrode array located between the low x-ray attenuating substrate and the photoconductive element.

13. The method of claim 10 , wherein the photoconductive element absorbs the first portion of the ionizing radiation and senses the optical photons.

14. A method of forming a radiation imaging sensor comprising:
forming a photoconductive element over a low x-ray attenuating substrate;
forming a photoelectric conversion layer over the photoconductive element;
forming a charge blocking layer over the photoelectric conversion layer;
forming a transparent conductive electrode over the charge blocking layer; and
forming a scintillator over the transparent conductive electrode, wherein an effective electron-hole pair (EHP) creation energy (W±) of the scintillator is substantially equal to an effective electron-hole pair (EHP) creation energy (W±) of the photoconductive element.

15. The method of claim 14 , further comprising forming a buffer layer over the photoconductive element prior to forming the photoelectric conversion layer.

16. A radiation imaging sensor, comprising:
a low x-ray attenuating substrate;
a photoconductive element disposed over the substrate; and
a scintillator disposed over the photoconductive element, wherein an effective electron-hole pair (EHP) creation energy (W±) of the scintillator is substantially equal to an effective electron-hole pair (EHP) creation energy (W±) of the photoconductive element.

Assignees

• Univ New York State Res Found

Inventors

• Zhao Wei
• Scheuermann James
• Howansky Adrian
• Lubinsky Rick
• Goldan Amirhossein
• Stavro Jann

Classifications

• G01T1/20 Primary

  with scintillation detectors · CPC title

• A61B6/4233 Primary

  using matrix detectors · CPC title

• G01T1/24

  with semiconductor detectors · CPC title

• G01T1/246

  utilizing latent read-out, e.g. charge stored and read-out later · CPC title

• H01L27/14612

  Electricity · mapped topic