Touch Display Device Current Path Switching for Flicker Reduction
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Solution Overview
Problem
Micro LED touch display devices experience screen flickering due to signal interference during the touch phase, which affects the user experience and can cause the light emitting elements to change brightness or emit light erroneously.
Innovation Solution
The touch display device is configured with a current path that is enabled during the display phase to provide a driving current to the light emitting elements and disabled during the touch phase to prevent signal interference. This is achieved by using power electrodes and pixel circuits with a switch that controls the current path, ensuring that the light emitting elements do not emit or flicker during the touch phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the touch display device uses a touch signal with oscillating waveform to detect touch events during the touch phase, then the touch detection sensitivity is improved, but the light emitting element may be interfered by the touch signal and cause brightness change or erroneous light emission
Solution Approach 1:
The patent implements periodic switching between display phase and touch phase, where the touch phase uses oscillating touch signals for detection while the display phase updates the screen. This periodic action allows the system to achieve both sensitive touch detection and stable light emission by separating these functions in time.
Solution Approach 2:
The patent pauses updating the display screen before the touch phase begins, preparing the system in advance to avoid signal interference during touch detection. This preliminary action ensures that the light emitting elements are in a stable state before the oscillating touch signal is applied.
2Reliability
If the display screen pauses updating during the touch phase to reduce signal interference, then the light emitting element stability is improved, but the display refresh rate is reduced causing visible flickering
Solution Approach 1:
The patent implements periodic switching between display phase and touch phase, where the display phase updates the screen at high refresh rates while the touch phase performs touch detection. This periodic action allows the system to achieve both stable light emission during touch detection and high display refresh rates during display updates, eliminating visible flickering.
3Adaptability or versatility
If separate electrodes are used for power supply and touch detection, then the functional independence is improved, but the number of power supplies increases leading to higher power consumption
Solution Approach 1:
The patent merges the power electrode with the touch electrode, allowing the same electrode to serve dual functions: providing power to the light emitting elements during the display phase and detecting touch events during the touch phase. This merging reduces the number of power supplies needed and lowers overall power consumption while maintaining functional independence through temporal separation.
Solution Approach 2:
The patent makes the power electrode universal by enabling it to perform multiple functions: it acts as a power supply electrode during the display phase and as a touch detection electrode during the touch phase. This multi-functionality reduces the total number of electrodes and power supplies required, thereby reducing power consumption.
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 solution effectively prevents screen flickering during the touch phase, while also reducing the number of power supplies needed by sharing the same electrode for both the first electrode and the touch electrode, thereby saving power consumption.
Implementation Method 1
The light emitting element is set on the current path. The touch display device is configured to enable the current path during a display phase to let the current path provide a driving current, the driving current is transmitted to the corresponding one of the plurality of power electrodes through the light emitting element to light up the light emitting element.
Data Source
AI summary
A touch display device comprises a plurality of first electrodes and a plurality of pixel circuits. Each of the plurality of first electrodes provides a first signal. Each of the plurality of pixel circuits comprises a current path and a light emitting element. The current path is coupled to a corresponding one of the plurality of first electrodes. The light emitting element is set on the current path. The touch display device is configured to enable the current path in a display phase to let the current path provide a driving current, the driving current flows through the light emitting element and to the corresponding one of the plurality of first electrodes to light up the light emitting element. The touch display device is further configured to disable the current path in a touching phase to let the current path stop providing the driving current.