Radiation Image Conversion Panel Surface Composition

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Solution Overview

Problem

Conventional radiation image conversion panels face issues with surface and side-face deterioration of phosphor crystals due to temperature changes and environmental factors, leading to reduced luminance and coalescence of columnar crystals, which affects performance.

Innovation Solution

A radiation image conversion panel with a vapor-deposited photostimulable phosphor layer containing an alkali metal halide phosphor, where the surface element composition has an alkali metal to halide ratio of 1.0 to 1.5, enhancing luminance and sharpness, and incorporating a manufacturing method that includes specific phosphor raw materials and vapor deposition techniques to maintain optimal crystal structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If vapor deposition is performed under conventional conditions, then phosphor crystals are formed, but the crystal surface deteriorates due to temperature change and environmental factors

Engineering Contradiction:

Improvecrystal surface stabilityVSAvoidsurface deterioration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters of the phosphor crystal surface by controlling the alkali metal to halide ratio within 1.0 to 1.5. This parameter optimization creates a more stable surface composition that resists deterioration from temperature changes and environmental exposure, directly resolving the contradiction between crystal formation and surface stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a protective environment by controlling the vapor deposition process in a controlled atmosphere and forming a surface composition that is less reactive to environmental moisture and gases. The optimized alkali metal halide surface acts as a protective layer that reduces harmful interactions with the external environment.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Illumination intensity

If conventional phosphor crystals are used, then image conversion is achieved, but luminance and sharpness deteriorate due to crystal coalescence

Engineering Contradiction:

ImproveluminanceVSAvoidcrystal structure integrity

Core Design Contradiction:

Illumination intensityVSShape

Solution Approach 1:

The invention optimizes the surface composition parameters (alkali metal to halide ratio of 1.0 to 1.5) to prevent crystal coalescence. This parameter control maintains distinct columnar crystal structures while enhancing luminance output, resolving the contradiction between maintaining crystal shape integrity and achieving high luminance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention performs preliminary surface composition optimization during the vapor deposition process itself, creating the optimal alkali metal to halide ratio before the crystals are exposed to environmental factors. This preliminary action prevents subsequent crystal coalescence and luminance deterioration that would occur with conventional phosphor crystals.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If surface treatment is applied to prevent deterioration, then crystal stability improves, but manufacturing complexity increases

Engineering Contradiction:

Improvecrystal surface stabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the surface treatment function into the vapor deposition process itself. By controlling the alkali metal to halide ratio during deposition, the surface composition is optimized in the same process that forms the crystals, eliminating the need for separate surface treatment steps and reducing manufacturing complexity while maintaining crystal stability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention enables the phosphor crystal to self-protect by creating an inherently stable surface composition during vapor deposition. The optimized alkali metal halide surface composition naturally resists deterioration from environmental factors without requiring additional protective coatings or treatments, making the material self-sufficient and simplifying manufacturing.

Inventive Principle:

Principle #25Self-service

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 improved luminance, sharpness, and aging stability of the radiation image conversion panels, as demonstrated by enhanced emission luminance and modulation transfer function values, maintaining performance even after aging.

Implementation Method 1

a vapor-deposited photostimulable phosphor layer containing an alkali metal halide phosphor

Methodology Applied

Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentUS7605380B2Radiation image conversion panel

Publication Date: 2009.10.20 KONICA MINOLTA MEDICAL & GRAPHICS INC

AI summary

Disclosed is a radiation image conversion panel comprising on a support a vapor-deposited photostimulable phosphor layer containing an alkali metal halide phosphor, wherein the surface element composition of the alkali metal halide phosphor exhibits a ratio of alkali metal to halide of 1.0 to 1.5.