Dual-Layer Touch Pad for Consistent Sleep-Mode Vibration
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Solution Overview
Problem
Existing touch pads in electronic devices provide inconsistent tactile feedback when in sleep mode due to capacitive sensors being in a low current state, leading to unpredictable user responses.
Innovation Solution
A touch pad system incorporating a capacitive sensing layer and a pressure sensing layer, with a processor controlling a vibration device to provide tactile feedback through both capacitance and pressure signals, ensuring consistent response even in sleep mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the capacitive sensor is used in low current state during sleep mode, then energy consumption is reduced, but tactile feedback consistency deteriorates
Solution Approach 1:
The touch pad is divided into two independent sensing layers: a capacitive sensing layer for detecting finger contact and a pressure sensing layer for detecting applied force. This segmentation allows each layer to function independently, with the pressure sensing layer providing reliable tactile feedback even when the capacitive sensor is in low current state during sleep mode.
Solution Approach 2:
The pressure sensing layer acts as an intermediary mechanism that bridges the gap between user interaction and tactile feedback. When a user touches the touch pad during sleep mode, the pressure sensing layer detects the applied force and triggers the vibration device to provide consistent tactile feedback, regardless of the capacitive sensor's power state.
2Ease of operation
If the capacitive sensor is activated to produce capacitance change, then touch detection is enabled, but response predictability deteriorates in sleep mode
Solution Approach 1:
The sensing system is segmented into two independent layers: capacitive sensing layer for touch detection and pressure sensing layer for force detection. The pressure sensing layer provides predictable and consistent response in sleep mode because it directly detects applied force without requiring capacitive sensor activation.
Solution Approach 2:
The system changes the detection parameter from capacitance (which requires sensor activation) to pressure (which can be detected in low current state). By switching to pressure sensing for touch pad activation during sleep mode, the system achieves more predictable and reliable responses while maintaining ease of operation.
3Device complexity
If only capacitive sensing is used, then device complexity is reduced, but tactile feedback reliability deteriorates in low current state
Solution Approach 1:
The sensing system is divided into two independent sensing layers with distinct functions. The capacitive sensing layer handles touch detection while the pressure sensing layer handles force detection and provides reliable tactile feedback in low current state. This segmentation allows the system to maintain reliability without requiring a complete redesign of the sensing architecture.
Solution Approach 2:
The pressure sensing layer serves multiple functions: it detects applied force, provides consistent touch detection in sleep mode, and enables reliable tactile feedback. This multi-functionality allows the system to improve reliability without proportionally increasing overall device complexity.
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
Ensures consistent tactile feedback by utilizing both capacitance and pressure signals to activate the vibration device, enhancing user experience by providing reliable tactile responses regardless of the device's power state.
Implementation Method 1
capacitive sensors comprising a plurality of conductive electrodes, which, in response to the touch or press from a user's finger, a change in capacitance is generated across the conductive electrodes
Implementation Method 2
a processor to drive a vibration device to vibrate when a change in capacitance is registered by the processor
Data Source
AI summary
A touch pad, comprises a housing comprising a vibration device, a cover, a capacitive sensing layer electrically connected to a processor and a pressure sensing layer arranged in the housing, also electrically connected to the processor. The capacitive sensing layer is positioned between the cover and the pressure sensing layer. The processor is configured to utilize a signal output from either the capacitive sensing layer or the pressure sensing layer to activate the vibration device.