High Resolution, High Speed Radiation Imaging A Layered X-ray Detector That Cuts Image Lag

This patent describes an X-ray imaging detector designed to capture both still and moving images at high resolution and high speed, while reducing the lingering “ghost” effect that troubles many digital radiation detectors. It is the work of KA Imaging, a Canadian company spun out of the University of Waterloo.

The Problem

Digital imaging devices that detect radiation such as X-rays, gamma rays and high-energy electrons often rely on amorphous semiconductor layers, made from materials like amorphous silicon or amorphous selenium, paired with a grid of electronic readout circuits. These amorphous semiconductors are well known to suffer from memory effects, including image lag). Lag shows up as a faint persistence of the previous image after a new one has been captured, caused by electrical charge becoming trapped inside the material and at the boundaries between layers. The trapped charge is then released erratically, smearing fast sequences of images and limiting how quickly and clearly the detector can work.

What This Invention Does

The patent sets out an imaging system that produces static and dynamic images from electromagnetic radiation. The detector is built as a stack of three main parts: a top electrode layer, a photoconducting layer that converts incoming radiation into electrical charge, and a bottom electrode layer that contains a set of pixel circuits for sensing that charge. A central design choice is that the photoconducting layer is made at least three times thicker than the pitch, or spacing, of an individual pixel circuit. This geometry helps the detector collect charge cleanly and quickly, supporting sharp images at high frame rates while limiting the charge-trapping behaviour that causes lag.

Key Features

• Layered detector stack. A top electrode, a photoconducting layer, and a bottom electrode carrying the pixel circuits.
• Thick photoconductor. The photoconducting layer is at least three times thicker than the pixel pitch to aid clean charge collection.
• Static and dynamic imaging. The system captures both single shots and moving sequences from X-rays and high-energy electrons.
• Reduced image lag. The design targets the charge-trapping memory effects that blur fast image sequences.
• High resolution and speed. Pixel-level sensing supports detailed images captured quickly.

Who Is Behind It

The applicant is KA Imaging Inc., a medical and industrial X-ray technology company based in Waterloo, Ontario, Canada. The named inventors are Karim S. Karim, Chris Scott and Yunzhe Li. The application is related to an earlier international filing under the Patent Cooperation Treaty.

Why It Matters

Faster, sharper radiation detectors with less image lag are valuable across medical radiography, veterinary imaging and industrial non-destructive testing, where moving images and rapid capture can reveal detail that a single static frame would miss. By tackling the charge-trapping problem at the level of detector structure, the approach aims to improve image quality without giving up speed. Protecting the design in Australia supports the company’s ability to bring its imaging products to the local medical and industrial markets.

Related Concepts

• X-ray detector – the broad class of device this invention improves.
• Photoconductivity – the effect that turns incoming radiation into a measurable signal.
• Image lag) – the persistence problem the design sets out to reduce.
• Radiography – a primary application area for the detector.
• Nondestructive testing – an industrial use for fast, high-resolution radiation imaging.

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AU 2026201914 was published in the Australian Official Journal of Patents on 2 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.