Touch Sensing Noise Mitigation via Sub-Burst Size Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High integration of proximity sensor devices and display devices in input-display devices leads to parasitic capacitances, causing touch-to-display noise due to capacitive coupling, which disrupts display artifacts, particularly in OLED displays.
Innovation Solution
A display controller with a touch sensing controller that drives sensing electrodes with a touch sensing waveform synchronized to a horizontal sync signal, using multiple modulations limited by a selected sub-burst size to mitigate interference, shifting the effective frequency away from ambient noise frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If high integration is used to combine proximity sensor device and display device, then device compactness is improved, but parasitic capacitances increase causing touch-to-display noise
Solution Approach 1:
The patent applies periodic action by using a touch sensing waveform that includes multiple modulations synchronized to horizontal sync signal instances. The waveform is structured in sub-bursts with specific numbers of modulations (e.g., 6, 12, 24 modulations per sub-burst) repeated periodically throughout the frame period. This periodic structure allows the sensing signal to be rhythmically applied and halted, creating predictable timing patterns that can be synchronized with display operations to mitigate parasitic capacitance effects.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the number of modulations in each sub-burst of the touch sensing waveform. Different sub-bursts can contain different numbers of modulations (e.g., alternating between 6 and 12 modulations), and the total number of sub-bursts can be configured based on frame period requirements. This flexibility in parameter adjustment allows optimization of the sensing signal characteristics to reduce interference with display operations while maintaining integration.
2Measurement precision
If touch sensing waveform with multiple modulations is used, then sensing precision is improved, but capacitive coupling onto display signals increases causing display artifacts
Solution Approach 1:
The patent applies segmentation by dividing the touch sensing waveform into multiple sub-bursts, where each sub-burst contains a specific number of modulations. The waveform is further segmented by synchronizing it to horizontal sync signal instances, creating distinct time segments within the frame period. This segmentation allows the sensing operation to be broken into manageable portions that can be timed to avoid interfering with critical display signal periods, thereby reducing capacitive coupling effects while maintaining sensing precision through the cumulative effect of multiple sub-bursts.
Solution Approach 2:
The patent uses periodic action by repeating the pattern of sub-bursts with specific numbers of modulations throughout the frame period. The waveform follows a periodic structure where sub-bursts are regularly spaced and synchronized to horizontal sync signals. This periodic repetition allows the sensing system to accumulate precision data over multiple cycles while the regular timing pattern enables synchronization with display operations to minimize artifacts.
3Object-affected harmful factors
If touch sensing signals are synchronized to horizontal sync signal, then interference with ambient noise is reduced, but flexibility in sensing waveform configuration is constrained
Solution Approach 1:
The patent implements dynamics by making the touch sensing waveform configuration adaptive rather than fixed. While the waveform is synchronized to horizontal sync signal instances, the system can dynamically adjust parameters such as the number of modulations per sub-burst (e.g., 6, 12, or 24 modulations), the number of sub-bursts per frame, and the distribution of modulations across sub-bursts. This dynamic configurability allows the system to optimize performance for different operating conditions and noise environments while maintaining synchronization with the display timing structure.
Solution Approach 2:
The patent applies parameter changes by allowing flexible configuration of multiple waveform parameters including the number of modulations in each sub-burst, the total number of sub-bursts, and the timing distribution within the frame period. These parameters can be adjusted to optimize the sensing waveform for specific ambient noise conditions while maintaining synchronization with horizontal sync signals. The ability to change parameters provides adaptability within the constraints of synchronization.
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
Effectively reduces display artifacts by synchronizing touch sensing signals with the horizontal sync signal and adjusting sub-burst sizes to minimize interference from ambient noise, thereby improving the display quality by reducing touch-to-display noise.
Implementation Method 1
The high integration may result in parasitic capacitances between components of the proximity sensor device and components of the display device. As a result, a sensing waveform, emitted by the proximity sensor device, may capacitively couple onto signals of the display device, thereby causing display artifacts.
Data Source
AI summary
A display controller includes a touch sensing controller configured to drive sensing electrodes with a touch sensing waveform that includes multiple modulations. The touch sensing controller is further configured to halt driving the plurality of sensing electrodes when a number of the modulations satisfies a selected sub-burst size. The touch sensing waveform is synchronized to an instance of a horizontal sync signal.