Transmission X-Ray Target Bonding on Low-Stress Diamond Substrates

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Solution Overview

Problem

Existing radiation generating devices face challenges with the durability of their targets, particularly due to heat dissipation issues and cohesion problems between the target layer and diamond substrates, leading to variations in radiation output and reliability concerns.

Innovation Solution

A method for manufacturing a transmission-type X-ray target with a diamond substrate that includes forming the target layer on a surface with lower residual stress, using a brazed joint and electrode to enhance cohesion, and optimizing the shape and material selection to reduce residual stress and prevent detachment of the diamond substrate fragments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If diamond substrate is used for supporting target layer, then heat dissipation performance is improved, but cohesion between target layer and substrate deteriorates due to low wettability and expansion coefficient mismatch

Engineering Contradiction:
Improveheat dissipation performanceVSAvoidcohesion between target layer and substrate
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

An intermediate layer is introduced between the diamond substrate and the target layer to serve as a mediator. This intermediate layer has better wettability with the target metal and more compatible thermal expansion properties, thereby improving adhesion while allowing the diamond substrate to maintain its superior heat dissipation function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The target structure employs a composite material system consisting of diamond substrate, intermediate layer, and target layer. Each material is selected for its specific properties: diamond for heat dissipation, intermediate material for adhesion and stress matching, and target metal for X-ray generation, creating a functionally optimized composite structure.

Inventive Principle:
Principle #40Composite materials

2Power

If target layer is made thin for transmission-type design, then radiation generation efficiency is improved, but durability and cohesion maintenance become more difficult

Engineering Contradiction:
Improveradiation generation efficiencyVSAvoiddurability and cohesion maintenance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The intermediate layer provides mechanical support and stress distribution for the thin target layer, enabling it to maintain structural integrity and withstand operational stresses despite its reduced thickness, thereby preserving both high radiation efficiency and durability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The target layer thickness is optimized within a specific range (1-10 μm) to balance X-ray transmission efficiency with mechanical durability. This parameter optimization ensures sufficient radiation generation while maintaining structural integrity through the supporting intermediate layer.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If brazed joint and electrode structure is used to enhance cohesion, then reliability of electrical connection is improved, but device complexity increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The brazed joint and electrode functions are merged into a single integrated structure. The electrode is formed as an integral part of the brazed joint assembly, combining electrical connection and mechanical bonding functions into one unified component, thereby improving reliability without proportionally increasing complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 results in a more reliable radiation generating device with stable radiation output and reduced risk of electrical discharges, enhancing the durability and performance of the X-ray target.

Implementation Method 1

heat can be efficiently dissipated from the target to the outside by using diamond as the material of a substrate

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

using a brazed joint and electrode to enhance cohesion

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP2757570B1Method of manufacturing transmission-type x-ray target
Publication Date: 2024.03.13 CANON KK
  • EP2757570B1 patent drawingFigure 1A~1E
  • EP2757570B1 patent drawingFigure 2A~2B
  • EP2757570B1 patent drawingFigure 3

AI summary

A transmission-type X-ray target (115) includes a flat plate-shaped diamond substrate (117) having a first surface (117a) and a second surface (117b) facing the first surface (117a) and a target layer (116) that is located on the first surface (117a). A residual stress of the first surface (117a) is lower than a residual stress of the second surface (117b).