Columnar Scintillator Phase Separation for Light Absorption Control

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Solution Overview

Problem

In composite scintillators, as the ratio of structural period to thickness in the optical waveguide direction decreases, most light is absorbed, making it difficult to achieve sufficient light entry into light receiving elements for effective imaging.

Innovation Solution

A scintillator with multiple columnar first phases and a surrounding second phase, incorporating an absorbing portion within the lower refractive index phase to control light absorption and enhance spatial resolution and image contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the ratio of structural period to thickness in the optical waveguide direction is decreased to improve light absorption, then light absorption is enhanced, but light entry into light receiving elements becomes insufficient

Engineering Contradiction:
Improvelight absorptionVSAvoidlight entry into light receiving elements
Core Design Contradiction:
Loss of energyVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by creating distinct phases with different refractive indices (first phase with higher refractive index, second phase with lower refractive index) in specific spatial arrangements. The absorbing portion is selectively placed in the lower refractive index phase at specific positions, creating localized light absorption zones that do not uniformly block light propagation, thus resolving the contradiction between light absorption and light entry into detectors.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The scintillator is segmented into multiple phases (first phase and second phase) with different optical properties. The absorbing portion is further segmented and positioned only in specific regions of the lower refractive index phase. This segmentation allows different regions to perform different functions: some regions guide light while others absorb light, resolving the contradiction between needing light absorption and maintaining light transmission to detectors.

Inventive Principle:
Principle #1Segmentation

2Use of energy by moving object

If the ratio of structural period to thickness is increased to improve light transmission, then light entry into light receiving elements is enhanced, but spatial resolution and image contrast deteriorate

Engineering Contradiction:
Improvelight entry into light receiving elementsVSAvoidspatial resolution and image contrast
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

By placing absorbing portions locally within the lower refractive index phase rather than uniformly distributing absorption, the patent maintains good light transmission while achieving spatial resolution enhancement. The localized absorbing portions suppress lateral light spread without significantly blocking vertical light transmission to detectors, thus improving spatial resolution while maintaining adequate light entry.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The lower refractive index phase with absorbing portions acts as an intermediary between the higher refractive index phase (which generates light) and the light receiving elements. This intermediary structure selectively manages light propagation: allowing vertical transmission while suppressing lateral spread, thus resolving the contradiction between light transmission and spatial resolution.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If uniform light absorption is implemented throughout the scintillator, then image contrast is improved, but overall light output is reduced

Engineering Contradiction:
Improveimage contrastVSAvoidoverall light output
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Instead of uniform light absorption, the patent implements local absorption by placing absorbing portions only in the lower refractive index phase at specific positions. This localized approach improves image contrast by suppressing lateral light spread while minimizing the overall impact on light output, as the higher refractive index phase continues to transmit light effectively to the detectors.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The scintillator is divided into phases with different absorption characteristics. The absorbing material is segmented and positioned only in specific regions (lower refractive index phase) rather than being uniformly distributed. This segmentation allows contrast improvement in critical regions while preserving overall light output through the non-absorbing phases.

Inventive Principle:
Principle #1Segmentation

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 absorbing portion effectively reduces light from the lower refractive index phase, improving spatial resolution and image contrast while maintaining sufficient light entry into light receiving elements, thus enhancing imaging quality.

Implementation Method 1

an absorbing portion is provided in part of one of the two kinds of phases, which has a lower refractive index

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a scintillator which emits light when radiation is applied thereto

Methodology Applied
Scientific EffectScintillation: Scintillation

Data Source

PatentEP2775319B1Scintillator having a phase separation structure and radiation detector using the same
Publication Date: 2019.11.13 CANON KK
  • EP2775319B1 patent drawingFigure 1A~1D
  • EP2775319B1 patent drawingFigure 2A~2E
  • EP2775319B1 patent drawingFigure 3~4

AI summary

In a related-art composite scintillator in which pores in a porous scintillator are filled with an absorbing member or the like, as the ratio between the structural period of the composite and the thickness in an optical waveguide direction becomes smaller, almost all light is absorbed, and, in some cases, it is difficult to obtain a sufficient light amount for forming an adequate image. Provided is a scintillator including multiple first phases having directionality in a direction connecting two surfaces thereof which are not located on a same surface and a second phase positioned around the first phases, in which each of the multiple first phases is in the shape of a column, and an absorbing portion is provided in part of one of the two kinds of phases, which has a lower refractive index.