Moisture Resistant Radiation Detector Core Assembly

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Direct conversion radiation detectors, particularly those with Cadmium Zinc Telluride (CdZnTe) layers, are sensitive to moisture, leading to increased leakage current, potential short circuits, and thermal degradation due to high encapsulation temperatures required for existing encapsulation methods, which compromise the detector's performance and longevity.

Innovation Solution

A method involving the assembly of a radiation detector core with a photon-electron conversion element and an integrated circuit, where a gaseous encapsulation material, such as parylene, is deposited onto all outer surfaces at temperatures below 100 degrees Celsius, ensuring a conformal and effective moisture barrier without the need for opening the encapsulation layer, thus protecting the detector from moisture and thermal degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If physical vapor deposition or chemical vapor deposition is used to apply encapsulation material, then a conformal encapsulation layer is formed, but the substrate temperature increases to 100-700 degrees Celsius which degrades the direct conversion material properties

Engineering Contradiction:

Improvemoisture barrier qualityVSAvoidsubstrate temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent changes the temperature parameter from conventional high-temperature processes (100-700°C) to room temperature or below 100°C processing. This is achieved by using alternative deposition methods that do not require thermal activation, thereby preserving the single crystal properties of the direct conversion material while still forming a conformal encapsulation layer.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal field (heat-based deposition) with an alternative mechanism that operates at low temperatures. The encapsulation material is deposited without relying on thermal energy, substituting the thermal process with a method compatible with temperature-sensitive materials.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If liquid encapsulation material is applied to the detector, then encapsulation is achieved, but good coverage of corners and edges is difficult to obtain

Engineering Contradiction:

Improveencapsulation coverageVSAvoidapplication difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces liquid-based encapsulation with a vapor-phase deposition process. The vaporized encapsulation material condenses conformally on all surfaces including corners and edges, eliminating the application difficulties associated with liquid materials while achieving complete coverage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the encapsulation layer is opened for contacting detector pixels, then electrical connection is enabled, but the moisture barrier is compromised

Engineering Contradiction:

Improveelectrical connectionVSAvoidmoisture barrier integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent performs the electrical connection before applying the encapsulation layer. Connection elements are attached to the detector pixels, and then the encapsulation material is deposited over these connections, sealing them within the encapsulation layer. This preliminary action eliminates the need to open the encapsulation later, maintaining the moisture barrier integrity.

Inventive Principle:

Principle #10Preliminary action

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 approach enhances moisture resistance and reduces thermal and mechanical stress on the detector, maintaining the integrity of the direct conversion material while eliminating the need for opening the encapsulation layer, thereby improving the detector's reliability and performance in radiation imaging applications.

Implementation Method 1

depositing a gaseous encapsulation material onto the assembled detector core assembly on all outer surfaces of at least the photon-electron conversion element and all of the at least one electrical connection elements

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

depositing a gaseous encapsulation material onto the assembled detector core assembly

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 3

the gaseous encapsulation material being a parylene precursor material that forms a parylene encapsulation layer on the assembled detector core assembly during or after the depositing step

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP3221894B1Radiation detector core assembly

Publication Date: 2019.05.29 KONINKLIJKE PHILIPS NV

Figure 1~2
Figure 3a~3c
Figure 4a~4b

AI summary

The present invention is directed towards a moisture resistant radiation detector core assembly which was constructed by first assembling the photon-electron conversion layer, integrated circuit and the connection elements between and then encapsulating the whole assembly. This provides improved moisture barrier properties, since the encapsulation also covers the connection elements and does not have to be opened to apply the electrical connections, as is done for known radiation detector core assemblies.