Touch Panel Event Detection With Sparse Sensing for Lower Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional touch screen panels face significant energy inefficiencies due to the continuous activation of all system elements to detect sparsely occurring signals, leading to unnecessary power consumption, especially in larger screens and mobile devices.
Innovation Solution
A signal processing method and device that utilizes compressed sensing to detect touch events first, followed by time division multiplexed sensing only in the detected event area, minimizing power consumption by continuous operation of the event detector and selective operation of the signal converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all system elements are continuously activated to detect sparsely occurring touch signals, then detection coverage is improved, but power consumption increases significantly
Solution Approach 1:
The patent divides the touch sensing system into two separate functional modules: an event detector using compressed sensing for sparse event detection, and a signal converter using TDM for precise coordinate measurement. This segmentation allows each module to operate optimally - the event detector consumes minimal power by only activating when touch events are detected, while the signal converter processes signals only in detected event areas, thereby resolving the contradiction between comprehensive detection coverage and power consumption.
Solution Approach 2:
The event detector performs preliminary detection of touch events using compressed sensing before the signal converter processes detailed coordinate information. This preliminary action filters out non-event periods, allowing the power-consuming signal converter to remain inactive during idle periods and only activate when actual touch events are detected, thus reducing overall power consumption while maintaining detection coverage.
2Use of energy by moving object
If compressed sensing is applied for touch detection, then power consumption is reduced, but reconstruction complexity increases
Solution Approach 1:
The patent extracts and separates the complex reconstruction process from the main detection workflow by implementing it as a dedicated reconstruction module that operates independently after the event detector and signal converter complete their functions. This extraction allows the main detection path to remain simple and power-efficient while confining the complex reconstruction algorithms to a separate module that only processes detected events, thereby reducing overall system complexity while maintaining power savings.
Solution Approach 2:
The patent introduces an event detector as an intermediary component between the touch screen and the reconstruction process. This intermediary uses compressed sensing to detect touch events and generates event maps that guide the subsequent signal processing, acting as a mediator that simplifies the overall system architecture by filtering and organizing information before it reaches the reconstruction module, thus managing complexity while preserving energy efficiency.
3Productivity
If time division multiplexed sensing is applied only in detected event areas, then processing speed is improved, but detection accuracy may be compromised
Solution Approach 1:
The patent applies different sensing methodologies to different spatial regions: compressed sensing is applied globally to detect touch events across the entire screen, while TDM is applied locally only in the detected event areas for precise coordinate measurement. This local quality approach ensures that processing speed is improved by limiting TDM to small event regions, while detection accuracy is maintained by using the more precise TDM method exactly where needed, rather than compromising accuracy across the entire screen.
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 approach reduces unnecessary power consumption and improves processing speed while minimizing complex reconstruction processes, optimizing energy efficiency for large touch screens.
Implementation Method 1
Touch information input by a user is recognized by reading changes in mutual capacitance (CM), which is a parasitic capacitance between the drive and sensor channels
Implementation Method 2
changes in mutual capacitance (CM), which is a parasitic capacitance between the drive and sensor channels
Data Source
AI summary
A signal processing apparatus for a touch input device is described. The apparatus includes: a plurality of drive channels arranged in an input area for a touch function; a plurality of sensor channels arranged to intersect the drive channels and configured to detect a change in capacitance of the input area according to a driving signal applied to the drive channels; and a readout IC configured to apply the driving signal to the drive channels and receive detection results from the sensor channels. The readout IC includes: an event detector configured to detect an event region and to enable a second driving signal; and a signal converter configured to measure a capacitance signal, convert the signal into a digital signal, and output the digital signal.