Multi-layer Scintillator Panel Activator Gradient
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Solution Overview
Problem
Current scintillator panels for radiographic imaging have insufficient emission luminance and sharpness, limiting their ability to enhance signal-to-noise ratio at low X-ray doses, despite efforts to improve light output and image quality.
Innovation Solution
A scintillator panel with a phosphor layer composed of multiple layers, where the activator concentration in the uppermost layer is significantly higher than in the underlying layers, with at least one layer containing no activator, optimizing the activator concentration ratio (B/A) to enhance emission luminance and sharpness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the phosphor layer thickness is increased to improve emission efficiency, then the light output increases, but the scattering of emission within the phosphor layer increases, leading to deteriorated sharpness
Solution Approach 1:
The phosphor layer is divided into multiple layers with different activator concentrations. The uppermost layer has a higher activator concentration (B mol%) optimized for light output, while lower layers have lower activator concentrations (A mol%) to reduce scattering. This segmentation allows each layer to contribute differently to the overall performance, achieving both high emission efficiency and sharpness simultaneously.
Solution Approach 2:
Different regions of the phosphor layer are assigned different activator concentrations based on their functional requirements. The uppermost layer receives a higher activator concentration to maximize light generation where X-rays first interact, while deeper layers use lower concentrations to minimize scattering and maintain image sharpness. This local optimization resolves the contradiction between emission efficiency and sharpness.
2Ease of manufacture
If a single-layer phosphor structure is used to simplify manufacturing, then the production process is easier, but the emission luminance and sharpness are insufficient
Solution Approach 1:
The phosphor layer is segmented into multiple layers with progressively different activator concentrations. This segmentation enables optimization of emission luminance and sharpness through controlled light generation and transmission, while the layers can be formed using sequential vapor deposition processes that are industrially feasible.
Solution Approach 2:
The activator concentration parameter is varied across different layers of the phosphor structure. By changing this chemical parameter from layer to layer, the patent achieves superior emission luminance and sharpness compared to uniform single-layer structures, while maintaining manufacturability through controlled deposition parameters.
3Ease of manufacture
If the activator concentration is made uniform throughout the phosphor layer to simplify composition, then the manufacturing process is easier, but the emission luminance is reduced
Solution Approach 1:
Instead of uniform activator concentration, the patent applies local quality by varying the activator concentration across different layers. The uppermost layer has a higher concentration (B mol%) to maximize light output, while lower layers have lower concentrations (A mol%). This non-uniform distribution optimizes emission luminance while remaining manufacturable through controlled deposition.
Solution Approach 2:
The phosphor layer is segmented into distinct layers with different activator concentrations. This segmentation allows optimization of emission luminance through strategic placement of high-activator regions where they are most effective, while avoiding the limitations of uniform composition.
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 multi-layer phosphor structure significantly improves emission luminance and sharpness, achieving better image quality and signal-to-noise ratio compared to single-layer panels, while maintaining enhanced emission efficiency.
Implementation Method 1
a phosphor layer containing a phosphor capable of emitting light upon exposure to radiation
Implementation Method 2
a columnar crystal structure of the phosphor can readily be formed through vapor deposition and its light guide effect inhibits scattering of emitted light within the crystal
Data Source
AI summary
A scintillator panel exhibiting enhanced emission luminance is disclosed, comprising a phosphor layer containing a phosphor capable of emitting light upon exposure to radiation, a substrate supporting the phosphor layer and a protective film covering the phosphor layer and the substrate, wherein the phosphor layer comprises two or more layers, and satisfying the following expression 1:1.0≦B/A≦1000 Expression 1:wherein B is an average activator concentration (mol %) of an uppermost phosphor layer, based on a phosphor and A is an average activator concentration (mol %) of the other phosphor layers, based on a phosphor.