Touch Sensing Signal Timing for Display Noise Cancellation
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Solution Overview
Problem
Touch sensing technologies face challenges in minimizing noise interference from display panels, which affects the accuracy of touch sensing due to synchronization requirements and limited sensing time during display panel operation.
Innovation Solution
A touch sensing device and system that utilize a driving unit to supply alternating driving signals with phase differences and adjust gap times to coincide with noise cycles, allowing for noise reduction by processing reaction signals from sensing electrodes, thereby generating accurate sensing data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If time-division scheme is used to separate display time and touch sensing time, then noise interference is reduced, but synchronization complexity increases and sensing time is limited
Solution Approach 1:
The patent applies periodic action by dividing the driving signal into multiple parts (first part driving signal, second part driving signal) that are supplied alternately during different time periods within each frame. This periodic modulation allows the touch sensing to operate throughout the entire frame period rather than only during blanking intervals, thereby increasing sensing time while maintaining noise rejection through the periodic structure that can be synchronized with or independent from display refresh cycles.
Solution Approach 2:
The patent implements dynamics by making the gap time adjustable and variable. The control unit can dynamically adjust the duration of gap time between the first and second part driving signals to coincide with noise cycles. This dynamic adjustment allows the system to adapt to different noise patterns and display refresh rates, enabling unsynchronized operation between display and touch sensing while optimizing noise cancellation performance.
2Measurement precision
If sensing time is extended beyond blanking intervals, then touch sensing accuracy improves, but noise interference increases
Solution Approach 1:
The patent applies segmentation by dividing the driving signal into distinct parts (first part driving signal and second part driving signal) separated by an adjustable gap time. This segmentation allows the system to collect reaction signals during active display periods while using the gap time to align with noise cycles, thereby extending effective sensing time beyond traditional blanking intervals while managing noise interference through structured signal division.
Solution Approach 2:
The patent implements parameter changes by making the gap time duration variable and adjustable. The control unit dynamically modifies the gap time parameter to coincide with noise cycles, allowing the system to optimize the balance between extending sensing time for improved accuracy and minimizing noise interference. This parameter adjustment enables the touch sensing to operate during periods when display noise characteristics are favorable.
3Productivity
If driving signals are supplied continuously, then productivity increases, but noise influence on sensing data increases
Solution Approach 1:
The patent applies periodic action by introducing a structured pattern of driving signal supply with periodic gap times. Instead of continuous driving, the system periodically interrupts the driving signal to create gap times that align with noise cycles. This periodic interruption maintains high productivity by keeping the overall duty cycle high while strategically removing driving during periods when noise would most interfere with sensing accuracy.
Solution Approach 2:
The patent implements skipping by strategically omitting the driving signal during specific gap time periods when noise interference would be most problematic. Rather than continuously supplying driving signals, the system skips driving during critical noise periods while maintaining driving during safer periods, thereby rushing through the frame period efficiently while avoiding noise contamination of sensing data.
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 effectively minimizes noise influence on touch sensing, improving accuracy and allowing for unsynchronized operation with display driving, even during overlapping cycles.
Implementation Method 1
The display panel is positioned close to the touch panel and thus may be coupled to electrodes (driving electrodes and sensing electrodes) disposed on the touch panel by a capacitance
Data Source
AI summary
An embodiment provides a touch sensing device configured to divide one driving cycle into two parts and to summate or subtract touch sensing data regarding respective parts, thereby removing periodic noise.