Capacitive Force and Biometric Input Surface for Non-Binary Touch
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Solution Overview
Problem
Existing input devices operate in a binary manner, limiting them to only two states, which restricts the ability to detect and measure force inputs effectively, making it advantageous to incorporate force sensing capabilities to enable non-binary inputs.
Innovation Solution
Incorporating one or more force sensors in input devices, such as capacitive force sensors with multiple electrodes and compliant materials, to detect force inputs applied to a cover element, allowing for the correlation of force signals with varying amounts of applied force, and potentially integrating biometric sensors and switch elements for additional functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If binary input operation is used, then device simplicity is maintained, but force detection capability is limited
Solution Approach 1:
The patent replaces traditional mechanical binary switches with capacitive sensing technology that measures force as continuous electrical signals. The capacitive sensor detects changes in capacitance caused by applied force, enabling continuous force measurement instead of binary on/off states, thus improving measurement precision while maintaining relatively simple device structure.
Solution Approach 2:
The patent changes the operational parameter from binary states to continuous force measurement by utilizing capacitance variations. The capacitive sensor measures different capacitance values corresponding to different force magnitudes, allowing the system to distinguish between multiple force levels rather than just presence or absence of pressure.
2Adaptability or versatility
If force sensing capability is added, then input versatility is improved, but device complexity increases
Solution Approach 1:
The patent integrates the capacitive sensor to serve multiple functions: it detects force magnitude, determines touch location, and can distinguish between different touch patterns (tap, press, hold). This single sensor component provides versatile input capabilities that would otherwise require multiple separate sensors or input mechanisms.
Solution Approach 2:
The patent combines the force sensing functionality with the existing input device structure by integrating the capacitive sensor into the cover element or underlying substrate. This merging approach allows force detection without adding separate, complex sensor systems, thus improving versatility while controlling complexity.
3Measurement precision
If capacitive force sensor is used, then force measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
The patent replaces complex mechanical force measurement mechanisms with capacitive sensing that can be fabricated using standard PCB or flexible circuit board techniques. The capacitive electrodes can be printed or etched onto substrates, enabling precise force measurement while maintaining ease of manufacturing through established electronic fabrication processes.
Solution Approach 2:
The patent changes the measurement approach from mechanical displacement to electrical capacitance measurement. This parameter change allows the use of electrical fabrication methods rather than precision mechanical assembly, improving measurement precision while simplifying manufacturing through electronic circuit production techniques.
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 the detection of force inputs across a continuum of values, allowing for non-binary input functionality, enhancing user interaction with electronic devices by associating different forces with distinct inputs or actions, such as controlling device functions or operations.
Implementation Method 1
The force sensor is a capacitive force sensor. The force sensor is formed with a first circuit layer that includes a first set of one or more electrodes and a second circuit layer that includes a second set of one or more electrodes... Each electrode in the first set is aligned in at least one direction (e.g., vertically) with a respective electrode in the second set to produce one or more capacitors. When a force is applied to the cover element, the cover element bends or deflects which causes at least one electrode in the first set to move closer to a respective electrode in the second set. The capacitance of the capacitor formed by the two electrodes varies as the distance between the electrodes decreases.
Data Source
AI summary
An input device can be integrated within an electronic device and/or operably connected to an electronic device through a wired or wireless connection. The input device can include one or more force sensors positioned below a cover element of the input device or an input surface of the electronic device. The input device can include other components and/or functionality, such as a biometric sensor and/or a switch element.