Display Device Touch Sensing Noise Isolation via Signal Timing
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Solution Overview
Problem
Display devices with input sensors face noise interference from signals used for driving the display, which complicates touch sensing due to overlapping signal periods.
Innovation Solution
A display device design that includes a driving controller and an input controller, with separate synchronization signal lines and a touch driving signal system that avoids overlapping periods with scan and data signals, using a vertical synchronization signal voltage regulator and horizontal synchronization signal voltage regulator to adjust signal amplitudes based on driving frequency, ensuring the touch driving signal does not coincide with scan or data signal periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the display device uses a single fixed driving frequency, then the touch sensing can be performed at a stable frequency, but the power consumption increases and noise interference occurs when scan and data signals are active
Solution Approach 1:
The patent implements dynamic frequency adjustment by varying the driving frequency of the display device according to different operating conditions. The controller changes the frequency at which scan signals and data signals are supplied to the display, thereby dynamically avoiding overlap with touch sensing operations and reducing power consumption during low-activity periods.
Solution Approach 2:
The patent employs periodic timing adjustments where touch sensing operations are scheduled at specific periods that do not overlap with scan and data signal periods. By periodically alternating between display driving and touch sensing at optimized intervals, the system achieves accurate touch detection while minimizing power consumption and noise interference.
2Use of energy by moving object
If the display device changes driving frequency to reduce power consumption, then energy efficiency improves, but noise interference increases affecting touch sensing accuracy
Solution Approach 1:
The system dynamically adjusts the driving frequency based on real-time operating conditions, selecting optimal frequencies that minimize noise interference during touch sensing operations. The controller monitors the state of scan and data signals and adapts the driving frequency accordingly to maintain touch sensing accuracy while achieving power savings.
Solution Approach 2:
The controller preliminarily schedules touch sensing operations at time periods that are predetermined to be free from scan and data signal activity. By advance planning the timing of touch sensing relative to display driving operations, the system prevents noise interference before it occurs, ensuring accurate touch detection even when operating at variable frequencies.
3Productivity
If scan signals and data signals are supplied simultaneously with touch driving signals, then the display operates efficiently, but noise from display signals interferes with touch sensing
Solution Approach 1:
The patent segments the operation timeline into distinct periods: display driving periods (when scan and data signals are supplied) and touch sensing periods (when touch driving signals are supplied). By temporally separating these operations into non-overlapping segments, the system maintains display efficiency while eliminating noise interference during touch sensing.
Solution Approach 2:
The system employs periodic alternation between display driving mode and touch sensing mode. During display periods, scan and data signals operate at full efficiency; during dedicated touch sensing periods, the display signals are suspended and touch driving signals are supplied. This periodic switching maintains overall productivity while preventing signal overlap and noise interference.
Data Source
AI summary
A display device includes a display including a plurality of pixels and an input sensor for sensing an input of a user. The display device includes: a driving controller for providing the display with a scan signal and a data signal according to a driving frequency; an input controller for providing a touch driving signal to the input sensor; a horizontal synchronization signal information line connecting the driving controller and the input controller, the horizontal synchronization signal information line transmitting a horizontal synchronization signal therethrough; and a vertical synchronization signal information line connecting the driving controller and the input controller, the vertical synchronization signal information line transmitting a vertical synchronization signal therethrough. Amplitude of the vertical synchronization signal or the horizontal synchronization signal varies according to the driving frequency.