Scintillator Array Reflective Layer Structure for Thermal Pitch Stability
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Solution Overview
Problem
The dimensional changes in scintillator arrays due to temperature fluctuations cause resolution deterioration in radiation detectors, particularly in X-ray CT scanners, leading to image degradation.
Innovation Solution
A scintillator array structure with a first reflective layer and a second reflective layer on an X-ray incident surface, bonded via an adhesive layer with controlled thickness, using a light transmissive resin with a low thermal expansion coefficient and reflective particles, to minimize warpage and maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflective layer containing resin is used in the scintillator array, then light reflection efficiency is improved, but dimensional stability deteriorates due to thermal expansion and contraction
Solution Approach 1:
The patent uses a composite reflective layer consisting of resin and reflective particles (such as aluminum oxide or titanium oxide). This composite structure provides both light reflection efficiency from the particles and flexibility in selecting resin materials with appropriate thermal expansion coefficients to minimize dimensional changes.
Solution Approach 2:
The patent carefully selects and controls the glass transition point of the resin (50°C or more, 60°C or less) and the thermal expansion coefficient (2×10^-5/°C. or less) to optimize both light reflection and dimensional stability. By adjusting these parameters, the reflective layer maintains performance across temperature variations.
2Measurement precision
If detection elements are made smaller to increase resolution, then image resolution is improved, but manufacturing precision deteriorates due to pitch shift and warpage
Solution Approach 1:
The patent selects resin with a thermal expansion coefficient of 2×10^-5/°C. or less to minimize thermal expansion during temperature variations (50°C to 60°C operation range). This prevents pitch shift between adjacent scintillator segments and maintains manufacturing precision despite smaller dimensions.
Solution Approach 2:
The adhesive layer with controlled thickness (2 μm to 40 μm) acts as an intermediary between scintillator segments, providing mechanical support and maintaining uniform spacing. This intermediary structure prevents warpage and ensures consistent pitch accuracy across the array.
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 reduces warpage and maintains uniform pixel pitch, enhancing image resolution and detection sensitivity by controlling dimensional changes, thus improving diagnostic image quality.
Implementation Method 1
a second reflective layer provided above the first surface via an adhesive layer
Implementation Method 2
using a light transmissive resin with a low thermal expansion coefficient and reflective particles, to minimize warpage
Implementation Method 3
a first reflective layer configured to reflect light... a second reflective layer having a film configured to reflect light
Implementation Method 4
The radiation detector converts X-rays incident on the scintillator segments into visible light
Data Source
AI summary
A scintillator array includes: a structure having at least one scintillator segment and a first reflective layer, the at least one scintillator segment and the first reflective layer having a first surface and a second surface, the at least one scintillator segment having a sintered compact containing a rare earth oxysulfide phosphor, and the first reflective layer being configured to reflect light; and a second reflective layer provided above the first surface via an adhesive layer, the adhesive layer having a thickness of 2 μm or more and 40 μm or less, and the second reflective layer having a film configured to reflect light.