Flexible Radiation Detector Structure to Prevent Layer Detachment
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Solution Overview
Problem
Radiation detectors in radiographic imaging devices face detachment issues between the sensor substrate and conversion layer when handled independently, particularly in configurations where the radiation detector and electric circuitry are arranged in a direction intersecting the stacking direction of the conversion and sensor substrate, with a bending adjustment member spanning across both.
Innovation Solution
The radiation detector incorporates a neutral stress plane adjustment member with specific thermal expansion properties and a cohesion layer at the interface, along with a buffer layer and fine particle layer to stabilize the sensor substrate and conversion layer, enhancing their cohesion and preventing detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bending adjustment member is provided spanning over the entirety of the radiation detector and electric circuitry, then the overall device bending is suppressed and stress concentration at low rigidity locations is prevented, but the sensor substrate may detach from the conversion layer when the radiation detector is handled on its own
Solution Approach 1:
The patent applies local quality by providing the neutral stress plane adjustment member only at specific regions (first region and second region) rather than spanning the entire device. The first region corresponds to the radiation detector area and the second region corresponds to the electric circuitry area, allowing localized adjustment of the neutral stress plane position to prevent detachment while maintaining overall structural integrity.
Solution Approach 2:
The patent segments the bending adjustment function into multiple independent neutral stress plane adjustment members positioned at different regions. Instead of using a single continuous bending adjustment member, the solution divides the adjustment function across multiple discrete members that can independently control stress distribution in their respective regions.
2Weight of moving object
If the radiation detector is made flexible using a flexible base member, then weight is reduced and imaging of the imaging subject is facilitated, but stress concentration occurs at locations with low rigidity
Solution Approach 1:
The patent applies parameter changes by adjusting the position of the neutral stress plane through the neutral stress plane adjustment members. By changing the structural parameters (position of neutral stress plane) in specific regions, the device achieves flexible handling while controlling stress distribution to prevent concentration at low rigidity locations.
3Shape
If a bending adjustment member spans the entirety of the radiation detector and electric circuitry, then overall device bending is controlled, but the radiation detector cannot be handled independently during manufacturing processes
Solution Approach 1:
The patent enables independent handling during manufacturing by providing neutral stress plane adjustment members only at specific regions (first and second regions) rather than a continuous spanning member. This localized approach allows the radiation detector to be separated and handled independently while still maintaining bending control where needed.
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 effectively suppresses detachment of the sensor substrate and conversion layer, even when the detector is handled independently, improving image quality and maintaining structural integrity during bending.
Implementation Method 1
a ratio of a coefficient of thermal expansion of the neutral stress plane adjustment member with respect to a coefficient of thermal expansion of the conversion layer is from 0.5 to 4
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
A radiation detector includes a sensor substrate, a conversion layer, and a neutral stress plane adjustment member. The sensor substrate includes a flexible base member, and a layer provided on a first surface of the base member and formed with plural pixels configured to accumulate electrical charge generated in response to light converted from radiation. The conversion layer is provided on the opposite side of the layer formed with the plural pixels to the side where the base member is provided and is configured to convert radiation into the light. The neutral stress plane adjustment member is provided on a second surface side of the base member on the opposite side of the base member to the first surface and is configured to adjust a position of a neutral stress plane to within a predetermined range in a stacking direction P in which the sensor substrate and the conversion layer are stacked from an interface at a face of the conversion layer opposing the sensor substrate.