Pixelated X-ray Scintillator Screen with Segmented Layers
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Solution Overview
Problem
Existing X-ray imaging technologies face limitations in detection efficiency, spatial resolution, and frame acquisition rates, with monolithic phosphor screens causing optical and X-ray scattering that deteriorate image quality.
Innovation Solution
A pixelated X-ray conversion screen is developed, comprising metal aperture sheets with small pixel holes filled with a scintillator material, arranged in a stack with aligned pixel holes and an intermediate metal sheet, and coated with a reflective layer, to enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a monolithic phosphor screen is used to increase detection efficiency, then the detection efficiency is improved, but optical and X-ray scattering occur that deteriorate image quality
Solution Approach 1:
The monolithic phosphor screen is segmented into multiple thin phosphor layers separated by reflective foil layers. Each phosphor layer has a thickness of 0.002 to 0.006 inches, which is significantly thinner than conventional monolithic screens. This segmentation reduces optical scattering within each layer while the reflective foil layers redirect photons that would otherwise be lost, thereby maintaining high detection efficiency while reducing image deterioration from scattering.
Solution Approach 2:
The invention introduces a multi-dimensional structure by stacking multiple phosphor layers with reflective foil layers in between, creating a layered architecture along the thickness dimension. This dimensional approach allows photons to interact with multiple phosphor layers at different depths, increasing the probability of X-ray conversion and detection while the reflective layers manage photon direction in the optical path dimension, effectively separating the functions of X-ray absorption and light emission.
2Reliability
If the thickness of the X-ray conversion medium is increased to improve detection efficiency, then detection efficiency is improved, but X-ray scattering increases that deteriorates image quality
Solution Approach 1:
Instead of using a single thick phosphor layer that would cause excessive X-ray scattering, the invention segments the total phosphor thickness into multiple thin layers separated by reflective foil. Each thin layer (0.002-0.006 inches) minimizes X-ray scattering while the cumulative thickness across multiple layers maintains high detection efficiency. The reflective foil layers between phosphor layers further reduce scattered X-ray effects by redirecting photons.
3Measurement precision
If pixel hole area is reduced to improve spatial resolution, then spatial resolution is improved, but detection efficiency decreases
Solution Approach 1:
The invention compensates for the reduced pixel hole area by utilizing the thickness dimension through multiple stacked phosphor layers. While each pixel hole is small (area ≤ 0.25 mm²) to maintain spatial resolution, the multiple phosphor layers increase the effective detection volume along the thickness direction. This allows small pixel holes to maintain high spatial resolution while the cumulative phosphor thickness across layers ensures sufficient X-ray interaction and detection efficiency.
Solution Approach 2:
The detection function is segmented across multiple phosphor layers, allowing each layer to contribute to the detection of X-rays that pass through or interact with it. This segmentation enables the system to maintain high detection efficiency with small pixel holes by distributing the detection function across multiple thin layers rather than requiring a single large pixel area.
4Manufacturing precision
If multiple metal aperture sheets are stacked to maintain pixel alignment, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The invention combines multiple functions into the stacked structure: the metal aperture sheets provide both the pixel hole pattern for spatial resolution and the structural framework for alignment, while the phosphor layers and reflective foil layers are integrated within this framework. The fiducial markers are incorporated into the metal aperture sheets themselves, merging alignment reference functionality with the structural component rather than requiring separate alignment mechanisms.
Solution Approach 2:
The metal aperture sheets serve multiple functions: they define the pixel hole geometry for spatial resolution, provide structural support for stacking, incorporate fiducial markers for alignment, and act as barriers between phosphor layers. This multi-functionality reduces the need for additional separate components, thereby managing device complexity while maintaining high manufacturing precision through the universal metal aperture sheet structure.
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
The solution improves image quality by increasing detection efficiency and reducing scattering, while maintaining spatial resolution and frame acquisition rates, resulting in enhanced contrast and clarity of high-energy X-ray images.
Implementation Method 1
a metal aperture sheet having a pixel hole filled with a scintillator material
Implementation Method 2
a sidewall of the metal aperture sheet forming the pixel hole is coated with a reflective coating
Data Source
AI summary
A pixelated X-ray conversion screen includes a metal aperture sheet having a pixel hole filled with a scintillator material, wherein an area of the pixel hole is equal to or less than about 0.25 mm2.