Capacitive Touch Input Position Error Correction
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Solution Overview
Problem
Capacitive touch input devices experience non-linearity in capacitance variation with touch position, leading to inaccuracies in determining touch input positions due to non-uniform patterns and 'dead zones' in electrode arrangements.
Innovation Solution
A method and device that utilize a table of possible capacitance variation combinations at touch nodes to determine the touch input position by identifying the central touch node with the greatest capacitance variation and surrounding nodes, correcting capacitance values to accurately calculate the touch input position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitance variation at touch nodes is used to determine touch input position, then touch input detection is enabled, but non-linearity in capacitance variation causes position accuracy degradation
Solution Approach 1:
The patent pre-calculates and stores correction values in a lookup table before actual touch input occurs. During operation, the system simply retrieves the appropriate correction value based on detected capacitance variations, avoiding real-time complex calculations and ensuring accurate position correction despite non-linear capacitance behavior
Solution Approach 2:
The patent transforms the non-linear capacitance variation data into corrected linear position information by applying pre-computed correction values. This parameter transformation converts the problematic non-linear relationship between capacitance and position into an accurate linear mapping, resolving the measurement precision issue
2Reliability
If lines are added to connect electrodes, then electrical connection is improved, but dead zones with non-uniform line density cause linearity deterioration
Solution Approach 1:
The patent introduces a lookup table as an intermediary component that mediates between the non-uniform capacitance variations caused by line distributions and the required linear position output. This intermediary stores pre-computed correction data that compensates for the non-uniformities introduced by the line connections, allowing accurate position detection despite the physical constraints of electrical connections
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 corrects touch input position errors caused by non-linearity, enhancing touch input resolution to match or exceed display pixel resolution, allowing for real-time accurate touch input detection and correction.
Implementation Method 1
a capacitance may be formed between the two electrodes... When a finger approaches or makes contacts with the touch node, the value of the capacitance at the touch node varies
Data Source
AI summary
Disclosed is a method for determining a touch input position, comprising the steps of: receiving a table including possible combinations, which can be formed with capacitance change values at a plurality of touch nodes, and information mapped to the possible combinations; acquiring a first combination related to capacitance change values at the plurality of touch nodes, which are generated by a touch input; acquiring first information mapped to the first combination by searching the table on the basis of the first combination among the possible combinations; and determining an input position of the touch input by using the acquired first information.