Radiation Detector Buried Layer Stray Light Suppression
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Solution Overview
Problem
Current radiation detectors, such as flat panel detectors, face challenges in achieving high image quality due to issues like stray light and light leakage, which deteriorate the modulation transfer function (MTF) and result in lower resolution.
Innovation Solution
The proposed radiation detector design includes a substrate with separately disposed device sections, a buried layer between them, and a wavelength conversion layer that converts radiation into light. The buried layer is positioned higher than the device sections' second surface to suppress stray light, and a light shielding film or a divided wavelength conversion layer is used to prevent light leakage, enhancing MTF and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If device sections are disposed separately from the substrate, then light leakage is suppressed and MTF is improved, but manufacturing complexity increases
Solution Approach 1:
The detector is divided into multiple independently disposed device sections separated by buried layers. This segmentation prevents light generated in one pixel from leaking into adjacent pixels, thereby improving MTF while maintaining a manageable manufacturing process through modular assembly
Solution Approach 2:
A buried layer is introduced as an intermediary substance between the substrate and device sections, and between adjacent device sections. This intermediary layer suppresses light leakage and provides electrical isolation, enabling separate disposal of device sections without compromising manufacturing feasibility
2Reliability
If a buried layer is formed between device sections, then stray light is suppressed and image quality is improved, but manufacturing steps increase
Solution Approach 1:
The buried layer serves multiple functions simultaneously: it acts as a light shield to suppress stray light, provides electrical isolation between device sections, and facilitates thermal management. By merging these functions into a single layer, the number of manufacturing steps is reduced despite the separate disposal of device sections
Solution Approach 2:
The buried layer is formed on the substrate before the device sections are disposed. This preliminary action simplifies the manufacturing process by preparing the light-shielding and isolation structure in advance, allowing device sections to be easily positioned and connected without requiring complex post-assembly steps
3Measurement precision
If the upper end of the buried layer is positioned higher than the device sections, then stray light is suppressed and MTF is improved, but manufacturing precision requirements increase
Solution Approach 1:
The buried layer is designed with varying heights: in the regions between device sections, it extends higher to suppress stray light effectively, while in the regions under device sections, it is lower to facilitate electrical connection. This local differentiation optimizes MTF without requiring uniform high precision throughout the entire structure
Solution Approach 2:
The buried layer extends slightly higher than the device sections in the inter-pixel regions, providing excessive light shielding coverage. This partial excessive action ensures complete stray light suppression with a simple geometric configuration, avoiding the need for complex precision control
4Measurement precision
If a light shielding film is formed on the device sections, then light leakage is suppressed and MTF is improved, but manufacturing complexity increases
Solution Approach 1:
The light shielding film is integrated with the existing device structure, serving both as a light shield and as part of the electrical connection system. This multi-functionality reduces the need for additional separate components, thereby improving MTF without significantly increasing device complexity
Solution Approach 2:
The light shielding film is formed by modifying the optical parameters of existing layers through deposition or doping, rather than adding completely separate structural elements. This parameter change approach suppresses light leakage while maintaining the existing device architecture, avoiding increased manufacturing complexity
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 design effectively suppresses stray light and light leakage, leading to improved MTF and high image quality, allowing for larger sensor upsizing while maintaining high performance.
Implementation Method 1
a wavelength conversion layer that is formed on the plurality of device sections and converts entered radiation into light
Data Source
AI summary
A radiation detector includes a substrate, a plurality of device sections each disposed separately from the substrate and each including a photoelectric conversion device, a buried layer formed in a region between the device sections, and a wavelength conversion layer that is formed on the plurality of device sections and converts entered radiation into light. Any of the device sections includes a first surface that faces the wavelength conversion layer, and a second surface that faces the substrate, and an upper end of the buried layer is disposed at a position higher than the second surface of the any of the device sections.