Touch Sensor Electrode Driving to Reduce Y-OCTA Flicker
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Solution Overview
Problem
Conventional Y-OCTA touch screen panels suffer from Low Ground Mass (LGM) issues causing signal detection malfunctions and flickering on the display panel due to the operation of the touch sensor, which existing solutions like dithering and adjusting driving voltage do not fully address.
Innovation Solution
The touch input device employs a control unit that applies different driving signals with reversed phases to second electrodes, subtracts differential signals, and integrates them to detect touch positions, reducing noise and preventing flickering, while also supporting stylus pen detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If dithering is used for each frame or driving voltage is lowered to reduce flicker, then flicker is partially reduced, but the flicker problem is not completely solved and touch detection accuracy deteriorates
Solution Approach 1:
The patent applies periodic driving signals with specific frequencies to the touch sensor electrodes, synchronizing the touch sensing operation with the display refresh rate. This periodic action eliminates flicker by ensuring that touch sensing operations occur at optimal moments in the display refresh cycle, rather than using dithering or voltage reduction which compromise detection accuracy.
Solution Approach 2:
The patent changes the driving parameters of the touch sensor, specifically adjusting the frequency and phase of driving signals applied to different electrode groups. By optimizing these parameters, the system achieves flicker-free display operation while maintaining high touch detection accuracy, avoiding the need to lower voltage or use dithering techniques.
2Measurement precision
If touch sensor operates continuously to ensure accurate touch detection, then touch detection accuracy is maintained, but power consumption increases
Solution Approach 1:
The patent implements periodic touch sensing operations synchronized with display refresh cycles. The touch sensor operates at specific intervals rather than continuously, reducing power consumption while maintaining accurate touch detection. The system activates touch sensing only when needed in the display refresh timeline, eliminating unnecessary continuous operation.
Solution Approach 2:
The patent dynamically adjusts the operating state of the touch sensor based on display refresh rate and touch input requirements. The system transitions between different operating modes (full sensing, reduced sensing, or idle) depending on current conditions, optimizing the balance between detection accuracy and power consumption rather than maintaining a fixed continuous operation state.
3Loss of time
If driving signals are applied to all second electrodes simultaneously to reduce operation time, then touch operation time is shortened, but flicker occurs on the display panel
Solution Approach 1:
The patent divides the second electrodes into multiple groups and applies driving signals to different groups in sequence rather than simultaneously. This segmentation allows the system to maintain reduced operation time while avoiding display flicker, as each electrode group is driven during optimized time windows that prevent interference with display refresh operations.
Solution Approach 2:
The patent uses periodic driving signals with different phases for different electrode groups, synchronizing them with the display refresh rate. This periodic action enables the system to drive multiple electrode groups in a coordinated sequence that minimizes total operation time while preventing flicker, rather than driving all electrodes simultaneously or sequentially one at a time.
4Device complexity
If LGM state occurs with single or double layer electrodes, then device structure is simplified, but signal detection malfunctions and flicker occur
Solution Approach 1:
The patent segments the electrode structure into multiple independent groups (first electrodes and second electrodes divided into sub-groups) that can be driven with different signals. This segmentation maintains the simplified single or double layer structure while enabling differential driving schemes that eliminate LGM-related detection malfunctions and flicker, improving reliability without adding structural complexity.
Solution Approach 2:
The patent introduces asymmetric driving signals with different phases and frequencies for different electrode groups within the simplified layer structure. This asymmetric driving approach creates differential signal patterns that counteract LGM effects, allowing the system to maintain structural simplicity while achieving reliable signal detection and flicker-free operation.
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 reduces flickering, shortens touch operation time, and decreases power consumption, while ensuring accurate touch detection and stylus pen signal recognition even in LGM states.
Implementation Method 1
the control unit is configured to subtract differential signals and integrate the same to detect touch positions
Implementation Method 2
the user can input information by touching the touch sensor while viewing the image displayed on the screen
Data Source
AI summary
A touch input device includes a touch sensor; and a control unit that controls the touch sensor, wherein the touch sensor includes a plurality of first electrodes and a plurality of second electrodes, the first electrode is disposed along a first direction, and the second electrode is disposed along a second direction different from the first direction, a 2a electrode pattern disposed immediately adjacent to the first electrode, and a 2b electrode pattern disposed at a distance apart by an interval from the first electrode and not immediately adjacent to the first electrode. The control unit controls different driving signals to be applied simultaneously to two second electrodes, wherein the driving signal applied to the 2b electrode pattern is applied to the 2a electrode pattern. The control unit detects the touch position of the object located on the touch sensor based on the signals received from the first electrodes.