Radiological Image Conversion Screen Using Ether-Group Ester Plasticizer
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Solution Overview
Problem
Radiological image conversion screens face challenges in maintaining flexibility and storage stability while maintaining sensitivity and sharpness, especially when exposed to high temperatures for long periods, and there is a need to avoid using phthalic acid esters due to environmental and health concerns.
Innovation Solution
A radiological image conversion screen comprising a support substrate with a phosphor layer containing phosphor particles, a polyvinyl acetal resin, and a carboxylic acid ester with an ether group, which enhances flexibility and storage stability without phthalic acid esters, and includes a urethane resin for improved sensitivity and sharpness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amount of phosphor is increased to improve sensitivity, then sensitivity is improved, but the thickness of the radiological image conversion screen increases causing visible light to be more easily diffused, resulting in a reduction in sharpness
Solution Approach 1:
The patent adjusts critical parameters including phosphor average particle size (5-20 μm), phosphor filling rate (70-90%), and screen thickness (200-400 μm) to optimize the balance between sensitivity and sharpness. By controlling these parameters within specific ranges, the patent achieves high sensitivity while maintaining image sharpness through reduced light diffusion.
2Ease of operation
If conventional plasticizers are used to maintain flexibility, then flexibility is maintained, but storage stability at high temperatures deteriorates and phthalic acid esters have negative environmental and health effects
Solution Approach 1:
The patent replaces conventional phthalic acid ester plasticizers with alternative plasticizer compounds that have superior thermal stability and environmental compatibility. The new plasticizers are selected to maintain the required flexibility of the radiological image conversion screen while resisting volatilization and degradation at high storage temperatures, thereby improving both ease of operation and reliability.
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 effectively maintains conventional sensitivity and sharpness while ensuring flexibility and storage stability, and prevents plasticizer volatilization and transfer, leading to a highly functional flat panel detector.
Implementation Method 1
radiological image conversion screens are used for converting radiation into visible light. Such a radiological image conversion screen includes a phosphor for X-ray, such as thallium-activated cesium iodide (CsI:Tl) or terbium-activated gadolinium oxysulfide (Gd2O2S:Tb) (GOS), and the phosphor for X-ray emits visible light according to irradiated X-ray
Data Source
AI summary
An object of the present invention is to provide a radiological image conversion screen where the flexibility and the storage stability of the radiological image conversion screen are sufficiently kept without phthalic acid ester while conventional sensitivity and sharpness being maintained, and another object thereof is to provide a radiological image conversion screen where a plasticizer in a phosphor layer is suppressed from volatilization and from transfer to other layers and/or films. The objects are solved by a radiological image conversion screen comprising a support substrate and a phosphor layer stacked on the support substrate, wherein the phosphor layer comprises phosphor particles, a polyvinyl acetal resin, and a carboxylic acid ester having an ether group.