Edge Force-Sensitive Interface Using Strain Gauge Sensors
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Solution Overview
Problem
Current electronic devices lack effective mechanisms for receiving force- or pressure-dependent user inputs, such as swipe, tap, and squeeze gestures, and do not adjust input mechanisms based on external contexts or environments.
Innovation Solution
The implementation of a force-sensitive interface using multiple strain gauge sensors disposed along the edge of an electronic device, which can detect the magnitude, location, and duration of applied forces, allowing for various user inputs and context recognition, such as being held or placed in a pocket, by normalizing input signals based on substrate deflection properties and analyzing force distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple strain gauge sensors are used to detect force inputs, then user input capability is improved, but device complexity increases
Solution Approach 1:
The housing is divided into multiple discrete sensor regions along the edge, each with its own strain gauge sensor. This segmentation allows the system to detect force inputs at multiple locations independently, enabling differentiated user interactions (e.g., squeezing left edge vs. right edge) while using simple, standardized sensor units that can be manufactured and integrated efficiently.
Solution Approach 2:
The strain gauge sensors serve multiple functions: they detect the presence of force, determine force magnitude, locate the position of applied force, and measure duration of contact. This multi-functionality is achieved through a single sensor type and processing approach, eliminating the need for separate sensor systems for each function and thereby reducing overall device complexity.
2Ease of operation
If strain gauge sensors are disposed at the edge rather than using physical buttons, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
Physical buttons that protrude from the housing are replaced with strain gauge sensors integrated into the housing structure itself. This substitution eliminates the need for mechanical button components, their associated mounting features, and moving parts. The strain gauges detect force directly through the housing material, providing a flush, sleek design while simplifying the manufacturing process by reducing the number of discrete components and assembly steps.
3Measurement precision
If force distribution analysis is performed to determine contact location, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The system performs force distribution analysis selectively rather than continuously. Processing is triggered only when force inputs are detected by the strain gauge sensors, allowing the device to enter a low-power state between user interactions. This approach maintains high measurement precision when needed while minimizing energy consumption during normal operation.
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
Enables a wide range of force-dependent user inputs and context awareness, reducing the need for physical buttons and minimizing power consumption, while providing a more intuitive and user-friendly interaction method.
Implementation Method 1
multiple strain gauge sensors disposed along the edge of an electronic device, which can detect the magnitude, location, and duration of applied forces
Implementation Method 2
normalizing parameter values of the received input signals based on a first deflection property of the first substrate layer, and a second deflection property of the second substrate layer
Data Source
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AI summary
A method includes one or more processors of an electronic device receiving signals from multiple sensors located along an edge of the device. The signals are received in response to external contact being provided to the edge of the device. At least one processor determines a distribution of forces applied to the sensors based on the input signals. Based on the determined distribution of forces, the processor determines: i) a location of the external contact that is offset from a location of each of the multiple sensors, and ii) a magnitude of the force of the external contact. The processor detects whether sensing criteria has been satisfied based on an analysis of: i) the location of the external contact and ii) the magnitude of the force of the external contact. Responsive to detecting that sensing criteria has been satisfied, the processor executes a user input action.