Radiation Image Conversion Panel Activation Gradient
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Solution Overview
Problem
Conventional radiation image conversion panels with a stimulable phosphor layer prepared by gas phase accumulation method face issues of surface degradation during storage due to exposure to environmental conditions, leading to uneven distribution of activating agents and performance degradation, particularly in luminance and sharpness.
Innovation Solution
A radiation image conversion panel with a phosphor layer containing alkali metal halide phosphor deposited by gas phase accumulation, where the activation agent ratio on the surface to the inner portion is controlled between 0.7 to 20, and luminance distribution by cathode luminescence is maintained at 50% or less, using Br or I as the main halide component with F content between 0 ppm to 10 ppm, and employing a support such as an organic polymer film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If gas phase accumulation method is used to prepare phosphor layer, then luminance and sharpness are improved, but surface degradation during storage occurs
Solution Approach 1:
The patent applies local quality by creating a gradient distribution of activating agents within the phosphor crystals, where the surface region has a different composition (higher F content, lower activating agent concentration) compared to the inner portion. This localized compositional variation protects the surface from degradation while preserving the bulk luminescent properties, directly resolving the contradiction between high luminance and surface stability.
Solution Approach 2:
The patent utilizes parameter changes by controlling the concentration distribution of activating agents and F content as a function of distance from the crystal surface. By varying these compositional parameters throughout the crystal volume, the patent achieves both high luminance (through optimized bulk composition) and surface stability (through protected surface composition), eliminating the need for binder materials.
2Productivity
If no binder resin is used in phosphor layer, then taking out efficiency of emitting light is improved, but phosphor surface is exposed to environmental conditions
Solution Approach 1:
The patent eliminates binder resin entirely while using local quality through compositional gradients within the phosphor crystals themselves. The surface regions of crystals are engineered with different properties (lower activating agent concentration, higher F content) to provide inherent environmental resistance, allowing the phosphor layer to function without binder protection while maintaining stability against environmental factors.
3Reliability
If surface treatment and lamination are applied, then surface degradation is prevented, but manufacturing complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for separate surface treatment and lamination processes by incorporating surface protection functionality directly into the phosphor crystal structure through compositional gradients. This integration removes additional manufacturing steps and materials, reducing overall process complexity while maintaining surface stability.
Solution Approach 2:
The phosphor crystals perform self-service by providing their own surface protection through the compositional gradient structure. The surface regions with modified composition (higher F content, lower activating agent concentration) inherently resist environmental degradation without requiring external protective layers or treatments, simplifying manufacturing by eliminating separate protection steps.
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 results in a radiation image conversion panel with enhanced luminance, sharpness, and storage stability, effectively addressing the issues of surface degradation and performance variability.
Implementation Method 1
the columnar crystal has a luminance distribution by cathode luminescence in the range of 50% or less
Implementation Method 2
an alkali metal halide phosphor which is deposited on the support by a gas phase accumulation method
Data Source
AI summary
Disclosed is a radiation image conversion panel containing a support having thereon a phosphor layer containing an alkali metal halide phosphor which is deposited on the support by a gas phase accumulation method, wherein the alkali metal halide phosphor includes a columnar crystal and an existing ratio of an activation agent of the columnar crystal on a surface of the columnar crystal to an inner portion of the columnar crystal is from 0.7 to 20.