Multifunction Keyboard With Embedded Capacitive Sensing Layer
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Solution Overview
Problem
Users of portable computing devices often need to switch between different input devices, such as keyboards and touchpads, to perform mechanical and touch inputs, which can be inconvenient and disrupt workflow.
Innovation Solution
A multifunction input device, such as a keyboard, incorporating a capacitive sensing layer with drive and sense electrodes, allows for both mechanical and touch inputs on a single surface, enabling users to provide inputs like cursor movement and icon selection without removing their hands from the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a keyboard includes separate mechanical input and touch input devices, then each input type can be detected accurately, but the user must move hands between devices disrupting workflow
Solution Approach 1:
The patent combines mechanical input capability (through keycaps) and touch input capability (through capacitive sensing layer) into a single keyboard device. The capacitive sensing layer is integrated beneath the keycaps and frame, allowing the same physical surface to detect both mechanical key presses and touch gestures, eliminating the need for separate input devices and maintaining workflow continuity
2Adaptability or versatility
If a capacitive sensing layer is integrated under keycaps, then touch input is enabled on the keyboard surface, but void spaces around electrical contacts create detection dead spots
Solution Approach 1:
The patent applies local quality by making the capacitive sensing layer non-uniform in its electrode arrangement. Drive electrodes and sense electrodes are strategically positioned to account for the presence of electrical contacts and void spaces. The electrode density and configuration are adjusted locally in different regions to compensate for areas where detection would otherwise be compromised by the underlying electrical contact structure
3Measurement precision
If drive and sense electrodes are arranged around void spaces, then touch detection is maintained across the surface, but capacitance variations require normalization processing
Solution Approach 1:
The patent implements feedback through a normalization process that uses detected capacitance values from various electrode pairs to adjust and equalize the sensitivity across the entire keyboard surface. The system measures baseline capacitance characteristics during manufacturing or initial use, then uses this information to normalize subsequent touch detections, compensating for variations introduced by the non-uniform electrode arrangement around void spaces
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 enables seamless transitions between input types on a single device, enhancing user experience by allowing continuous input without hand movement, and calibrates capacitance changes to normalize detection across the surface, reducing disruptions and improving accuracy.
Implementation Method 1
detecting a first change in capacitance in response to received input at a first location on the touch-sensitive keyboard and detecting a second change in capacitance in response to input received at a second location on the touch-sensitive keyboard
Data Source
AI summary
Disclosed herein is a multifunction input device, such as, a keyboard. The multifunction input device has a capacitive sensing layer that enables a user to use the multifunction input device as standard keyboard and also as a touch sensitive surface such as, for example, a trackpad.