Optical fiber pressure sensor array or grid for location, vibration and/or motion sensing and mattress including the same
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Solution Overview
Problem
Existing optical fiber pressure sensor arrays for location sensing lack enhanced sensitivity, making them less effective for precisely and reliably sensing and monitoring movements of a subject.
Innovation Solution
The optical fiber pressure sensor array incorporates a planar grid of Polymer Optical Fibers (POF) with a mechanical structure that includes a flexible, light-scattering material and a rigid material. This configuration allows for enhanced fiber bending and optical coupling, increasing sensor sensitivity by curving the transmitting and receiving optical fibers at intersecting points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical structure with flexible material is provided on both sides of the pressure sensor, then fiber bending is enhanced and sensor sensitivity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the flexible material from between the fibers and places it only on the outer surface, eliminating the need for complex multi-layer mechanical structures while maintaining the fiber bending effect. This simplifies the device structure while preserving sensor sensitivity.
Solution Approach 2:
The patent uses a thin flexible layer on the outer surface to enable fiber bending when pressure is applied. This thin film approach achieves the desired mechanical effect without requiring complex rigid mechanical structures, thereby reducing device complexity while maintaining measurement precision.
2Measurement precision
If optical fibers are curved at intersecting points, then optical coupling is enhanced and measurement precision improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent pre-curves the optical fibers at intersecting points during the manufacturing process. This preliminary action ensures that the fibers are already in the optimal curved configuration before assembly, reducing the need for precise post-assembly adjustments and lowering overall manufacturing precision requirements.
Solution Approach 2:
The patent modifies the physical state of the fibers by curving them at intersecting points, changing their geometric parameters to optimize optical coupling. This parameter change enhances measurement precision while the curving is performed during manufacturing when materials are more pliable, reducing the actual precision burden during final assembly.
3Measurement precision
If rigid material is used to concentrate pressure on intersection points, then sensor response is improved, but risk of permanent fiber deformation increases
Solution Approach 1:
The patent uses a flexible thin film on the outer surface instead of rigid materials to concentrate pressure. This flexible film transmits pressure to the fiber intersection points effectively for good sensor response, while its flexibility prevents permanent deformation of the fibers, thereby maintaining both measurement precision and fiber reliability.
Solution Approach 2:
The patent employs a composite structure combining flexible material with the optical fiber array. This composite approach allows the flexible outer layer to concentrate pressure effectively on the intersection points for improved sensing response, while simultaneously protecting the fibers from excessive stress that would cause permanent deformation, thus maintaining reliability.
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 enhanced mechanical structure significantly increases sensor sensitivity, allowing for more precise detection of pressure changes, which improves the reliability of sensing and monitoring movements and vibrations of a subject.
Implementation Method 1
When a pressure is applied on the pressure sensor as shown in FIG. 2c, the flexible scattering material exerts a pressure on the optical fibers, thereby causing the optical fibers to bend slightly.
Implementation Method 2
The escaped light is then scattered in all directions in the light-scattering material of the first layer and partially couples into the receiving optical fiber again.
Implementation Method 3
The mechanical structure allows to enhance waveguide bending when pressure is applied to the pressure sensor.
Data Source
AI summary
The present disclosure relates to an optical fiber pressure sensor array or grid for location, vibration and/or motion sensing including:a plurality of receiving optical fibers, anda plurality of transmitting optical fibers,wherein said plurality of receiving optical fibers and said plurality of transmitting optical fibers are arranged in a planar array to define pressure sensors at respective points,wherein a mechanical structure is provided at one or both sides of each pressure sensor to enhance fiber bending when a pressure is applied to the pressure sensor, said mechanical structure including a first, internal layer contacting the optical fibers and made of a flexible, light-scattering material, and a second, external layer made of a rigid material,wherein said plurality of receiving optical fibers and/or said plurality of transmitting optical fibers is curved at the intersecting point defining the pressure sensor.