OLED Touch Electrode Timing to Reduce LGM Flicker Noise

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Solution Overview

Problem

Conventional touch input devices with Y-OCTA touch screen panels experience issues with Low Ground Mass (LGM) state malfunctions and display flicker due to the direct deposition of touch sensors on OLED panels, leading to signal disruptions and noise.

Innovation Solution

A touch input device design featuring a touch sensor with cross-disposed first and second electrodes, controlled by a touch controller that synchronizes with display panel synchronization signals, adjusts driving times, and employs differential amplification to minimize noise and flicker, improving touch accuracy and reducing LGM state errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a touch sensor is directly deposited on an OLED panel (Y-OCTA technology), then manufacturing cost is reduced and panel thickness is minimized, but display flicker and noise occur due to interference between touch sensor driving signals and display panel signals

Engineering Contradiction:

Improvemanufacturing costVSAvoiddisplay flicker and noise

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The touch sensor electrodes are divided into multiple groups (first electrode group and second electrode group) that are driven at different time periods. This temporal segmentation allows the touch sensing function to be maintained while avoiding simultaneous interference with the display panel driving signals, thereby reducing display flicker and noise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The touch sensor employs periodic driving with multiple time periods, where different electrode groups are activated in alternating periods. This periodic action synchronizes touch sensing operations with the display refresh cycle, minimizing interference and eliminating flicker effects while maintaining continuous touch functionality.

Inventive Principle:

Principle #19Periodic action

2Speed

If touch sensor driving frequency is increased to improve touch responsiveness, then touch detection speed is improved, but display flicker and noise are exacerbated

Engineering Contradiction:

Improvetouch detection speedVSAvoiddisplay flicker and noise

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The touch sensor uses periodic driving with multiple time periods, where different electrode groups are activated in alternating periods. This periodic action synchronizes touch sensing operations with the display refresh cycle, minimizing interference and eliminating flicker effects while maintaining continuous touch functionality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The driving frequency and timing of the touch sensor electrodes are dynamically adjusted based on the display refresh rate and touch interaction requirements. This dynamic adjustment allows optimal touch responsiveness while synchronizing with the display panel to minimize flicker and noise.

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If dithering or variable refresh rate techniques are used to reduce flicker, then some flicker mitigation is achieved, but the flicker problem is not completely solved and touch accuracy may be compromised

Engineering Contradiction:

Improveflicker mitigationVSAvoidtouch detection accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The touch sensing operation continues uninterrupted through continuous alternating driving of different electrode groups. This continuous useful action ensures that touch detection accuracy is maintained while the periodic segmentation eliminates flicker, unlike dithering techniques that may introduce gaps or reduce sensing precision.

Inventive Principle:

Principle #20Continuity of useful action

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

The solution effectively minimizes display noise and flicker, enhances touch sensitivity, and improves touch functionality in the Low Ground Mass state by synchronizing touch sensor operations with display panel signals and using differential amplification to filter out noise.

Implementation Method 1

the touch controller is configured to drive the touch sensor in synchronization with at least one horizontal synchronization signal applied to the display panel

Methodology Applied

Scientific EffectSynchronization:

Implementation Method 2

employs differential amplification to minimize noise and flicker

Methodology Applied

Scientific EffectDifferential amplification:

Data Source

PatentUS20240393901A1Touch input device

Publication Date: 2024.11.28 HIDEEP INC

AI summary

A touch input device according to the present invention is a touch input device including a display panel, and the touch input device comprises a plurality of first electrodes and a plurality of second electrodes disposed to cross the plurality of first electrodes. A touch sensor and a touch controller are electrically connected to the plurality of the first electrodes and the plurality of the second electrodes. The touch controller is configured to control the touch sensor, wherein the second electrode comprises a pair of electrode portions, one electrode portion of the pair of electrode portions is disposed adjacent to at least one part of the plurality of first electrodes, and the other one of the pair of electrode portions of the second electrode is disposed adjacent to the plurality of electrode portions. At least one of the first electrodes is disposed adjacent to the remaining portion of electrodes.