Bi-layer Scintillator Reflectors for CT Cross-talk Reduction

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Solution Overview

Problem

Current CT imaging systems face challenges in maintaining high light output and preventing light and x-ray cross-talk between scintillators in detector arrays, which affects image quality and accuracy.

Innovation Solution

The integration of bi-layer reflectors with a conformal smoothing layer and a mirror layer, specifically using aluminum, interstitially between scintillators in the detector arrays, along with a composite layer to absorb light and x-ray photons, reduces cross-talk and enhances light output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional single-layer reflectors are used between scintillators, then manufacturing is simpler, but light output is insufficient and cross-talk between scintillators occurs

Engineering Contradiction:

Improvelight outputVSAvoidreflector structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining a conformal smoothing layer (organic polymer material) with a mirror layer (aluminum or silver) to create a bi-layer reflector. This composite structure provides both the smoothness needed for high light reflection and the reflective properties of metal, achieving superior light output and cross-talk prevention compared to single-layer reflectors.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating a conformal smoothing layer that specifically addresses the rough surface of the scintillator. This layer provides localized smoothness at the interface with the mirror layer, enabling high reflectivity without requiring the entire reflector structure to be complex. The smoothing layer is applied only where needed - at the scintillator-reflector interface.

Inventive Principle:

Principle #3Local quality

2Illumination intensity

If rough surfaces are present on scintillators, then manufacturing is easier, but light reflection is scattered and cross-talk increases

Engineering Contradiction:

Improvelight reflectionVSAvoidsurface smoothness

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by forming the conformal smoothing layer on the scintillator surface before applying the mirror layer. This preliminary smoothing action creates a uniform base that enables the subsequent mirror layer to achieve high reflectivity. The rough surface is pre-treated with the polymer smoothing layer, which flows into and fills surface irregularities, creating a smooth interface for optimal optical performance.

Inventive Principle:

Principle #10Preliminary action

3Illumination intensity

If adhesion layers or reducing agents are used in the reflector structure, then layer bonding is improved, but light absorption increases and light output decreases

Engineering Contradiction:

Improvelight outputVSAvoidlayer adhesion

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent applies self-service by designing the conformal smoothing layer to inherently provide both smoothing and adhesion functions. The organic polymer material with specific properties (refractive index 1.4-1.7, thickness 0.1-5 micrometers) self-adheres to both the scintillator and the mirror layer, eliminating the need for separate adhesion layers or reducing agents. This self-service approach maintains high light output while ensuring proper layer bonding.

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

This configuration maintains high light output while minimizing cross-talk between scintillators, leading to improved image quality and accuracy in CT imaging systems.

Implementation Method 1

a conformal smoothing layer...filling in surface irregularities

Methodology Applied

Scientific EffectSurface smoothing:

Implementation Method 2

a mirror layer...reflective layer...aluminum

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 3

a composite layer to absorb light and x-ray photons

Methodology Applied

Scientific EffectPhoton absorption: Absorption (EM radiation)

Implementation Method 4

each scintillator converts x-rays to light energy

Methodology Applied

Scientific EffectScintillation: Scintillation

Data Source

PatentUS8247778B2Scintillator arrays and methods of making the same

Publication Date: 2012.08.21 GE PRECISION HEALTHCARE LLC

AI summary

A scintillator array and method for making the same are provided. The array comprises a bi-layer reflector further comprising a conformal smoothing layer and a mirror layer. The bi-layer reflector does not comprise an intervening reducing agent or adhesion layer and/or comprises aluminum. Further, the mirror layer may be deposited via gas phase metallization, allowing application to tightly confined spaces. A detector array comprising the scintillator array is also provided.