Touch Sensing Coil Structure for Compact Force Input
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Solution Overview
Problem
Existing touch sensing devices in wearable electronics face challenges with mechanical switches, including large size, non-sleek design, susceptibility to electric shock, and difficulty in implementing dust and water protection, which limits their integration and functionality.
Innovation Solution
A touch sensing device featuring a force sensing unit with a sensing coil and a metal portion that changes its overlapping region with the coil in response to touch, allowing for both position and size adjustments, enabling efficient use of internal space and hybrid capacitive and inductive sensing for contact and force touch inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical switch is used in wearable devices, then switch function is implemented, but device size increases and design becomes non-sleek
Solution Approach 1:
The patent replaces the mechanical switch system with a touch sensing device that uses capacitive or resistive sensing elements. This substitution eliminates the need for mechanical moving parts, reducing the overall device volume while maintaining the switch function through touch-based actuation. The sensing element can be integrated directly into the display or case structure, achieving a sleek, minimalist design.
Solution Approach 2:
The patent merges the switch function with the display structure or case body by integrating the sensing element into these existing components. This consolidation eliminates separate switch mechanisms, reducing device volume while maintaining functionality. The touch-sensitive region is combined with the display surface or case structure, creating a unified, sleek appearance without protruding mechanical elements.
2Ease of operation
If a mechanical switch is used in wearable devices, then switch function is implemented, but protection against dust and water becomes difficult
Solution Approach 1:
The patent replaces mechanical switches with touch sensing elements that have no moving parts or gaps. This eliminates pathways for dust and water infiltration, enabling IP68 or similar high-level protection ratings. The sensing element can be fully sealed within the device structure, maintaining reliability in harsh environments while preserving switch functionality through touch actuation.
Solution Approach 2:
The patent employs thin-film sensing elements that can be sealed within protective enclosures. These flexible or rigid thin films serve as both the sensing medium and a barrier against environmental contaminants. The sealed structure prevents dust and water penetration while allowing touch input to be detected through the protective layer.
3Ease of operation
If a mechanical switch is used in wearable devices, then switch function is implemented, but risk of electric shock increases
Solution Approach 1:
The patent replaces mechanical switches with capacitive or resistive touch sensing elements that operate at low voltages and currents. This eliminates the high-voltage switching contacts that pose electric shock risks in mechanical switches. The touch sensing mechanism detects user input through changes in electrical properties (capacitance or resistance) without requiring direct contact with high-voltage circuitry, thereby reducing electric shock risk while maintaining switch functionality.
4Volume of moving object
If touch sensing device with metal portion and sensing coil is used, then sensitivity and space efficiency are improved, but device complexity increases
Solution Approach 1:
The patent employs a metal portion that serves multiple functions: it acts as a structural support element, a shielding layer for electromagnetic interference, and an active component in the inductive sensing mechanism. The sensing coil serves dual purposes as both the excitation source and the detection element. This multi-functionality reduces the number of separate components needed, thereby reducing overall device complexity despite the advanced sensing capabilities.
Solution Approach 2:
The patent implements a nested structure where the sensing coil is positioned within or adjacent to the metal portion, which itself is integrated into the device housing or internal structure. This nesting arrangement maximizes space utilization while minimizing the number of discrete components. The sensing coil, metal portion, and housing are arranged in concentric or layered configurations that reduce overall device volume and simplify assembly.
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 sensitivity and reduces the required internal space in electronic devices, allowing for more compact and protective touch sensing capabilities, including simultaneous detection of contact and force touches without the need for mechanical switches.
Implementation Method 1
a force sensing unit including a sensing coil; and a metal portion. At least a portion of the metal portion is in contact with the force sensing unit, and the touch sensing device is configured such that a region of the metal portion overlapping with the sensing coil changes in response to a touch being applied
Data Source
AI summary
A touch sensing device includes: a force sensing unit including a sensing coil; and a metal portion. At least a portion of the metal portion is in contact with the force sensing unit, and the touch sensing device is configured such that a region of the metal portion overlapping with the sensing coil changes in response to a touch being applied to the touch sensing device.