Flexible X-ray Detector Using Thin Glass Substrate
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Solution Overview
Problem
Conventional digital X-ray detectors face challenges in fabricating flexible organic X-ray detectors on thin glass substrates due to thermal expansion mismatch between flexible plastic and rigid glass substrates, leading to distortion, handling errors, and stability issues, which hinder mass production of lightweight and dimensionally stable detectors.
Innovation Solution
A method involving the fabrication of a thin film transistor array on a glass substrate, subsequent thinning of the glass substrate, and bonding it to a flexible substrate, along with the deposition of an organic photodiode and scintillator layer, to create a flexible yet robust X-ray detector that maintains mechanical stability and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a flexible plastic substrate is used for TFT panel fabrication, then the X-ray detector achieves lightweight and flexibility, but the high CTE causes significant thermal expansion mismatch leading to distortion and handling errors
Solution Approach 1:
A thin glass substrate is introduced as an intermediary carrier between the flexible plastic substrate and the TFT/OPD layers. The glass substrate provides a stable platform for precise photolithographic fabrication while the flexible substrate ultimately provides lightweighting and flexibility. This mediator resolves the contradiction by decoupling the fabrication precision requirement from the final flexible, lightweight structure.
Solution Approach 2:
The detector structure is segmented into multiple functional layers: a flexible plastic substrate for lightweighting, a thin glass substrate for fabrication stability, TFT array for signal processing, OPD for detection, and scintillator for X-ray conversion. This segmentation allows each layer to optimize for its specific function, resolving the contradiction between flexibility and manufacturing precision.
2Stability of the object's composition
If a thick glass substrate (0.5-1.1 mm) is used for TFT panel fabrication, then the X-ray detector achieves dimensional stability during processing, but the weight increases and flexibility is limited
Solution Approach 1:
The glass substrate thickness parameter is optimized to a thin range (15-50 micrometers) rather than using conventional thick glass (0.5-1.1 mm). This parameter change reduces weight and improves flexibility while maintaining sufficient dimensional stability during fabrication through the use of a temporary carrier substrate and controlled processing conditions.
Solution Approach 2:
The patent employs a thin glass substrate (thin film) rather than thick glass, enabling the detector to achieve both dimensional stability during fabrication and flexibility in the final product. The thin glass substrate acts as a flexible shell that provides structural support without excessive weight or rigidity.
3Weight of moving object
If a thin glass substrate is used to reduce weight, then the X-ray detector achieves desired weight reduction, but stability is impeded and processing becomes difficult without protection
Solution Approach 1:
The thin glass substrate is permanently bonded to the flexible plastic substrate, merging the advantages of both materials. The glass provides dimensional stability and protection for the thin structure, while the flexible substrate provides lightweighting and flexibility. This combination resolves the contradiction between thinness and stability.
Solution Approach 2:
The TFT array and OPD layers are fabricated on the thin glass substrate before final assembly, with the glass substrate serving as a protective carrier throughout the fabrication process. This preliminary use of the glass substrate as a protected platform enables subsequent handling and processing without damaging the thin structure.
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 enables the production of flexible organic X-ray detectors that are dimensionally stable, lightweight, and resistant to thermal expansion, improving handling and imaging capabilities while reducing weight and maintaining detection efficiency.
Implementation Method 1
Certain digital X-ray detectors include a scintillator disposed over a photodetector that converts the impinging radiation to low-energy photons that are suitable for detection by the photodetector
Implementation Method 2
The photodetector, in turn, produces a separate electrical signal that is indicative of X-rays detected at a corresponding location of the detector element
Data Source
AI summary
A flexible organic X-ray detector, an imaging system including the flexible organic detector and methods for fabricating a flexible organic X-ray detector having a layered structure are presented. The detector includes a flexible substrate and a thin glass substrate operatively coupled to the flexible substrate. Further, the detector includes a thin film transistor array disposed on the thin glass substrate. Additionally, the detector includes an organic photodiode including one or more layers disposed on the thin film transistor array. Moreover, the detector includes a scintillator layer disposed on the organic photodiode.