Touch Panel Driving Signal Offset Reduction
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Solution Overview
Problem
Conventional touch panels using Walsh-Hadamard codes for driving signals suffer from large offsets, which hinder accurate touch input detection and panel miniaturization.
Innovation Solution
A touch panel design that generates periodic driving signals with voltages not equal to zero, ensuring the sum of driving signals is zero during each time zone, reducing offsets and improving touch input accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Walsh-Hadamard codes are used for driving signals, then touch panel functionality is achieved, but large offsets occur reducing measurement precision
Solution Approach 1:
The patent modifies the driving signal parameters by ensuring the sum of driving signals is zero during each time zone while maintaining non-zero voltages. This parameter change eliminates AC offsets without compromising touch panel functionality, directly resolving the contradiction between reliability and measurement precision.
2Ease of operation
If conventional driving signals are used, then touch detection is possible, but AC offsets reduce signal-to-noise ratio
Solution Approach 1:
The patent converts the harmful AC offsets into beneficial zero-sum driving signals. By designing driving signals where the sum equals zero during each time zone, the previously harmful offset components become useful for eliminating noise and improving signal-to-noise ratio while maintaining touch detection capability.
3Ease of operation
If driving signals with offsets are used, then touch panel operation is maintained, but panel miniaturization is hindered
Solution Approach 1:
The patent changes the driving signal parameters to have zero sum during each time zone, which eliminates AC offsets. This parameter modification enables panel miniaturization by removing the need for offset compensation circuits, while maintaining full touch panel operational capability.
Data Source
AI summary
A touch panel includes a touch sensing circuit including a plurality of driving electrode lines and a plurality of sensing electrode lines, which intersect the driving electrode lines. The touch panel further includes a driving signal generation circuit that generates a plurality of driving signals and transmits the driving signals to the driving electrode lines, and a sensing circuit that receives a plurality of sensing signals from the sensing electrode lines. The driving signals have voltages that are not equal to zero during a first time zone, and the sum of driving signals generated at the same time is maintained to be equal to zero during the first time zone.