Solid-State Digital Detector Light Guide for Optical Erasure
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Solution Overview
Problem
Conventional X-ray radiation detectors face issues with non-homogeneous illumination due to the thickness and high time constants of light-emitting diode or OLED light generators, leading to ghost images and slow response times, especially in medical imaging applications where detectors are large and in motion.
Innovation Solution
A solid-state digital radiation detector with a light guide that distributes light uniformly across the photosensitive elements, using a light source at the lateral periphery of the guide to increase the distance light travels, reducing the distinctiveness of light sources and enabling high-frequency, short-pulse operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a matrix of light-emitting diodes is used to optically erase photosensitive elements, then the photosensitive elements can be reset, but the thickness of the light generator causes non-homogeneous illumination and ghost images
Solution Approach 1:
The patent transitions from a planar matrix of light-emitting diodes to a three-dimensional light guide structure. The light source is positioned at the periphery and light is distributed through the light guide volume to achieve uniform illumination across the photosensitive elements, resolving the thickness-related non-homogeneity issue.
Solution Approach 2:
The patent introduces a light guide as an intermediary component between the light source and the photosensitive elements. This light guide mediates the light distribution, transforming the point-source illumination into uniform area illumination and eliminating ghost images caused by direct light source visibility.
2Ease of operation
If conventional light generators are used, then optical erasure is achieved, but the high time constants result in slow response times incompatible with high-frequency operation
Solution Approach 1:
The patent changes the temporal parameters of the light generation system by using a light guide with high light transmission speed. The light guide enables rapid light pulse transmission with minimal time constants, allowing the system to operate at high frequencies and achieve fast response times compatible with modern imaging requirements.
3Area of stationary object
If OLED layers with ITO electrodes are used for large surface areas, then coverage is achieved, but the high resistivity causes non-homogeneous brightness with greater illumination at edges than centre
Solution Approach 1:
The patent inverts the conventional approach by positioning the light source at the periphery rather than behind the entire detector surface. Light enters through the light guide at the edges and is distributed uniformly across the photosensitive elements, reversing the illumination pattern and eliminating the edge-enhanced non-homogeneity characteristic of ITO electrode approaches.
4Adaptability or versatility
If the air gap between light generator and detector changes due to detector motion, then adaptability to motion is achieved, but ghost images of the light generator appear on the images
Solution Approach 1:
The light guide acts as a mechanical and optical intermediary that decouples the light source from the photosensitive elements. This intermediary structure absorbs and compensates for relative motion between the light generator and detector, maintaining stable light distribution and preventing ghost images even when the air gap varies due to detector motion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the size and number of light sources, minimizes image deformation, and facilitates easier replacement, while providing homogeneous illumination and faster response times, thus improving image quality and reducing the likelihood of artifacts.
Implementation Method 1
said light guide being configured to distribute light from said at least one light source over the entire matrix of photosensitive elements
Implementation Method 2
the light generator is configured such that said at least one light source injects light through at least one of the faces of the light guide
Implementation Method 3
The photosensitive elements are made from semiconductor materials... A photosensitive element comprises at least one photodiode, phototransistor or photoresistor... which carry out a photoelectric conversion and deliver electrical signals
Implementation Method 4
a radiation converter, also called a scintillator screen, which comprises a layer of a scintillating substance. This substance has the property, when it is excited by such radiation, of emitting radiation of longer wavelength, for example visible light
Data Source
AI summary
A solid-state digital detector for detecting incident radiation, the detector includes a photosensitive sensor and a light generator, the photosensitive sensor comprising photosensitive elements organized in a matrix, the light generator being intended to optically erase the photosensitive elements, wherein the light generator comprises: a light guide comprising a front face facing the front of the detector, a rear face opposite the front face and at least one side face extending between the front face and the rear face, and at least one light source arranged at the lateral periphery of the light guide, and wherein the light generator is configured such that the at least one light source injects light through at least one of the faces of the light guide, the light guide being configured to distribute light from the at least one light source over the entire matrix of photosensitive elements.