Waterproof Stretchable LED Arrays for Biomedical Integration
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Solution Overview
Problem
Conventional inorganic light emitting diodes (LEDs) and photodetectors are restricted by their rigid semiconductor wafers, limiting their application in flexible and biologically compatible environments, such as biomedical and robotics fields, where integration with flexible substrates like plastic, paper, or textiles is needed.
Innovation Solution
Development of stretchable and flexible optical devices incorporating micro-scale inorganic semiconductor elements, integrated with sutures or substrates, featuring a waterproof barrier layer to prevent electrical short circuits and limit net leakage current, enabling interaction with biological tissues and environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rigid semiconductor wafers are used in conventional LEDs and photodetectors, then device performance and stability are maintained, but flexibility and adaptability to biological environments are lost
Solution Approach 1:
The patent employs thin film encapsulation layers (e.g., parylene, PDMS) and flexible substrate structures that allow the rigid semiconductor wafer to be integrated onto flexible supports. This enables the device to bend and conform to biological surfaces while the rigid semiconductor core maintains its electrical and optical performance characteristics.
Solution Approach 2:
The invention creates a composite structure combining rigid semiconductor materials with flexible polymers and biocompatible materials. The semiconductor wafer is mounted on flexible substrates and encapsulated with multiple layers of flexible materials, creating a hybrid device that exhibits both the electrical stability of rigid semiconductors and the mechanical flexibility of soft materials.
2Adaptability or versatility
If rigid semiconductor wafers are used, then manufacturing precision and device reliability are maintained, but integration with flexible substrates like plastic, paper, or textiles becomes difficult
Solution Approach 1:
The device is divided into separate functional modules: the rigid semiconductor wafer is processed and tested independently, then mounted onto flexible substrates through standardized interfaces. This segmentation allows each component to be manufactured using optimized processes and simplifies the integration of rigid and flexible elements.
Solution Approach 2:
Flexible mounting substrates and adhesive layers serve as intermediaries between the rigid semiconductor wafer and the final flexible application substrate. These intermediary layers accommodate thermal expansion differences, mechanical property mismatches, and enable straightforward integration of rigid components onto flexible bases.
3Reliability
If conventional sealed devices are used in biological environments, then protection from water exposure is achieved, but electrical short circuits and leakage current still occur
Solution Approach 1:
Multiple thin film encapsulation layers (such as parylene C, PDMS, or other biocompatible polymers) are deposited over the semiconductor device to create a waterproof barrier. These flexible films prevent water penetration while allowing the device to maintain its electrical isolation and avoid short circuits in wet biological environments.
Solution Approach 2:
The device incorporates a composite encapsulation structure combining hydrophobic polymer layers with biocompatible materials. This multi-layer composite provides both waterproofing and electrical insulation, preventing both water ingress and electrical short circuits while maintaining flexibility for biological applications.
4Reliability
If waterproof encapsulation is added to protect from water, then electrical short circuit prevention is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Thin film deposition techniques are used to apply encapsulation layers directly onto the device structure in a sequential manner. This approach adds protection without requiring complex assembly steps, as each layer is deposited conformally over previous layers and device features, maintaining relative simplicity in the manufacturing process.
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
These devices provide reliable performance in biologically compatible environments, allowing for sensing, treating, and actuating biological tissues while maintaining mechanical integrity and preventing electrical interference, thus expanding their use in biomedical and robotics applications.
Implementation Method 1
one or more barrier layers at least partially encapsulating the one or more flexible or stretchable LED arrays, at least part of the one or more flexible or stretchable PD arrays, or at least parts of both, wherein the barrier layer prevents water from a biological environment from contacting at least a portion of the inorganic LEDs
Implementation Method 2
incorporating a barrier layer component for limiting a net leakage current from the flexible or stretchable electronic circuit to the biological environment to an amount that to an amount which does not adversely affect the tissue and/or biological environment
Data Source
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AI summary
Described herein are flexible and stretchable LED arrays and methods utilizing flexible and stretchable LED arrays. Assembly of flexible LED arrays alongside flexible plasmonic crystals is useful for construction of fluid monitors, permitting sensitive detection of fluid refractive index and composition. Co-integration of flexible LED arrays with flexible photodetector arrays is useful for construction of flexible proximity sensors. Application of stretchable LED arrays onto flexible threads as light emitting sutures provides novel means for performing radiation therapy on wounds.