Steering Wheel Sensor Mat Printing for Integrated Signal Shielding
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Solution Overview
Problem
Current steering wheel sensor mats face challenges due to signal interference from the metal steering wheel frame, complex manufacturing processes, and limited flexibility in design and materials, leading to increased manufacturing time and material constraints.
Innovation Solution
The development of sensor mats with printed sensing and shielding loops using conductive ink on a versatile base substrate and insulating material, allowing for customizable designs and reduced noise interference through adjustable insulation thickness and flexible ink patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wire loops are sewn to fabric or foam substrate, then the sensor mat can be manufactured with traditional methods, but the manufacturing process becomes time consuming and complex
Solution Approach 1:
The patent replaces the mechanical sewing process with a printing process. Conductive ink is printed directly onto the substrate to form sensing loops, eliminating the need for physical wire stitching. This substitution of printing technology for mechanical sewing reduces manufacturing complexity and time while maintaining the electrical connectivity function of the sensor loops.
Solution Approach 2:
The patent changes the physical state and form of the conductive element from discrete wires to a continuous printed ink pattern. By controlling the printing parameters (ink composition, deposition method, drying conditions), the sensor mat can be manufactured more efficiently with reduced steps and lower labor intensity compared to traditional wire sewing methods.
2Reliability
If separate sensor mat and shield mat are used, then shielding can be provided, but the device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The patent combines the sensor loop and shield into a single integrated mat structure. The conductive ink is printed to form both sensing elements and shielding elements within the same substrate layer, eliminating the need for separate sensor and shield mats. This integration reduces device complexity while maintaining shielding effectiveness through proper spatial arrangement of the printed conductive patterns.
Solution Approach 2:
The printed conductive ink pattern serves multiple functions simultaneously: it creates the sensing loops for hand detection and provides shielding against electromagnetic interference. The same printing process and conductive material are used for both sensor and shield functions, simplifying the overall device architecture while achieving reliable signal protection.
3Manufacturing precision
If fixed wire stitch layout is used, then the sensor mat can be manufactured consistently, but adaptability to different steering wheel specifications is limited
Solution Approach 1:
The patent transitions from a fixed, static wire stitch layout to a dynamic, programmable printed pattern. The conductive ink can be deposited in varying configurations using digital printing control, allowing the sensor mat design to be easily adapted to different steering wheel specifications. The printing process enables rapid reconfiguration of sensor loops and shields without requiring new physical templates or fixtures.
Solution Approach 2:
The patent uses variable printing parameters (pattern geometry, trace width, spacing, loop size) to adapt the sensor mat design to different steering wheel configurations. By controlling the printing process parameters, the same manufacturing system can produce diverse sensor patterns with consistent precision, achieving both manufacturing repeatability and design versatility.
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 solution enhances the manufacturing efficiency and flexibility of sensor mats, reduces signal interference, and allows for more precise and efficient installation around the complex steering wheel shape, improving the overall performance and reliability of hand-sensing systems.
Implementation Method 1
The printed sensing loops are made with conductive ink that is disposed upon the base substrate or the insulating layer from a print head, for example, and adheres thereto.
Implementation Method 2
The sensor mats include one or more printed shielding loops adjacent the sensing loops and separated from the sensing loops by a layer of insulating material.
Implementation Method 3
This configuration allows shielding for the sensing loops as part of the sensing mat, which may reduce unwanted electrical interference with the electrical signal(s) carried by the sensor mat caused by the sensor mats proximity with the steering wheel rim
Data Source
AI summary
Systems and methods of printing sensor loops on a sensor mat for use in a steering wheel are disclosed herein. For example, the sensor mat may include a base substrate, one or more printed sensing loops, and an insulating material. The printed sensing loops are made with conductive ink that is disposed upon the base substrate or the insulating layer from a print head and adheres thereto. These sensor mats are versatile with respect to the type of base substrate and insulating materials that may be used, the shape of the sensing loops, and the area each loop may occupy. Shielding loop(s) may also be printed adjacent the sensing loop(s). This configuration allows shielding for the sensing loops as part of the sensing mat, which may reduce the thickness of the steering wheel rim and manufacturing and installation times.