Capacitive Touch Panel Coarse-Fine Scanning Method
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Solution Overview
Problem
Conventional capacitive touch panels face limitations in resolution due to increased driving duration and power consumption, particularly with the scan driving method and multi-line selection driving method, respectively.
Innovation Solution
A coarse/fine sensing method is introduced, dividing the scan into two phases: a first scan to determine a first analysis position and a second scan where the signal is applied only to the determined position, allowing for increased sampling and reduced power consumption by grouping transmission electrodes and performing multiple samplings at the first analysis position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the scan driving method is used to increase resolution, then measurement precision is improved, but driving duration increases
Solution Approach 1:
The patent divides the transmission electrodes into multiple groups and segments the scanning process into two phases: a first scan that covers all groups to identify a first analysis position, and a second scan that focuses only on the identified position to determine the second analysis position. This segmentation allows comprehensive coverage for accuracy while limiting the detailed scan duration.
Solution Approach 2:
The first scan serves as a preliminary action that quickly identifies the region of interest (first analysis position) before the second, more precise scan is performed. This preliminary identification step prevents the need for exhaustive scanning of all electrodes, thereby reducing overall driving duration while maintaining measurement precision.
2Measurement precision
If the multi-line selection driving method is used to increase resolution, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent segments the electrode scanning into two distinct phases with different power consumption characteristics. The first scan operates at lower power across all groups, while the second scan concentrates power only on the identified first analysis position, significantly reducing overall power consumption compared to simultaneous multi-line driving.
Solution Approach 2:
Instead of applying signals to all transmission electrodes simultaneously (excessive action), the patent applies signals only to the necessary subset of electrodes in the second scan (partial action). This partial action approach maintains measurement precision by focusing resources on the region of interest while reducing overall power consumption.
3Productivity
If signals are applied to all transmission electrodes simultaneously, then productivity is improved, but power consumption increases
Solution Approach 1:
The patent segments the high-speed scanning into two phases: the first scan maintains productivity by covering all groups, while the second scan reduces power consumption by limiting signal application to only the identified first analysis position. This segmentation allows the system to achieve both high productivity and low power consumption at different stages.
Solution Approach 2:
The patent implements periodic action by alternating between two scanning modes: a comprehensive first scan phase and a focused second scan phase. This periodic switching allows the system to maintain high productivity during the first scan while reducing power consumption during the second scan, achieving an overall balance between the two competing requirements.
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 method enhances touch position accuracy and reduces power consumption by allocating sufficient duration to each transmission electrode and minimizing the number of signals applied, resulting in improved performance compared to conventional methods.
Implementation Method 1
a touch sensor 100 senses coordinates corresponding to a touched portion using a capacitive change generated at a crossing between a transmission electrode and a receiving electrode due to a touch
Data Source
AI summary
In the touch panel device and the operating method for the same according to the present invention, an entire scan is divided into a first scan and a second scan for determining a touch position. In the first scan, a plurality of transmission electrodes are configured into groups, and a signal is applied sequentially or simultaneously such that a first analysis position is determined. In the second scan, since a signal is sequentially or simultaneously applied only to the first analysis position, a plurality of sampling durations can sufficiently be provided such that a second analysis position, which is the exact touch position, can be determined.