Touch Panel Scan Method for Power Reduction
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Solution Overview
Problem
Conventional touch panels face increased power consumption and scan time as the size of display devices grows, necessitating a method to reduce these inefficiencies while maintaining accurate touch detection.
Innovation Solution
Implementing a method that performs a limited scan to detect coarse touch positions by activating only a portion of driving and sensing lines, followed by a local scan to detect fine positions, thereby reducing the number of active lines and minimizing power consumption and scan time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all driving lines and sensing lines are activated to scan all touch points, then complete touch detection coverage is achieved, but power consumption and scan time increase
Solution Approach 1:
The patent divides the touch panel into multiple regions and activates only the driving lines and sensing lines corresponding to the region where a touch is detected during the limited scan. This segmentation approach ensures complete detection coverage when needed while significantly reducing power consumption by leaving other regions inactive during each scan cycle.
Solution Approach 2:
The patent performs a limited scan that activates only a partial set of driving lines and sensing lines (specifically, lines with indices that are multiples of a predetermined value) to detect touch points. This partial action reduces power consumption and scan time while maintaining sufficient detection accuracy for most applications.
2Reliability
If all driving lines and sensing lines are activated to scan all touch points, then complete touch detection coverage is achieved, but scan time increases
Solution Approach 1:
The patent segments the scan process into a limited scan phase (activating only necessary lines) and a local scan phase (activating lines around the detected touch). This segmentation reduces overall scan time by avoiding unnecessary scans of empty regions while maintaining complete detection coverage when required.
Solution Approach 2:
The patent performs a preliminary limited scan to quickly identify the region containing the touch point before performing a more detailed local scan. This preliminary action significantly reduces scan time by avoiding unnecessary scanning of the entire panel, while still ensuring complete touch detection coverage.
3Use of energy by stationary object
If a limited scan activates only a portion of driving and sensing lines, then power consumption and scan time are reduced, but touch detection accuracy may be compromised
Solution Approach 1:
The patent activates only driving lines and sensing lines with indices that are multiples of a predetermined value during the limited scan. This partial action reduces power consumption and scan time while maintaining sufficient detection accuracy through the subsequent local scan that refines the touch position.
Solution Approach 2:
The limited scan serves as a preliminary action that quickly identifies the touch region with reduced power consumption. The subsequent local scan then provides precise touch position measurement. This two-stage approach ensures measurement precision is maintained while significantly reducing overall power consumption compared to scanning all lines.
4Use of energy by stationary object
If a local scan activates only driving lines and sensing lines adjacent to the coarse position, then power consumption is reduced, but scan time for the entire panel increases
Solution Approach 1:
The patent performs a preliminary limited scan across the entire panel to identify the touch region before performing the local scan. This preliminary action ensures that the subsequent local scan can be performed efficiently only in the relevant region, reducing total scan time while maintaining low power consumption during the local scan phase.
Data Source
AI summary
A method of operating a touch panel including a plurality of driving lines and a plurality of sensing lines includes performing a first limited scan by activating only a first portion of the plurality of driving lines and only a first portion of the plurality of sensing lines, such that a first coarse position of a first touch by a user is detected, and performing a first local scan by activating only driving lines and sensing lines adjacent to the detected first coarse position of the first touch, such that a first fine position of the first touch by the user is detected.