Gate Driver Circuit Stress Distribution in Display Devices
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Solution Overview
Problem
In-cell touch sensor technology in display devices experiences reduced image quality and shortened lifespan of gate driver circuits due to signal interference and DC gate bias stress, leading to line dim phenomena and reliability issues.
Innovation Solution
The display device employs a timing controller to synchronize the touch sensing unit with the display driving circuit by shifting the touch sensing period and display periods every predetermined time, distributing the stress across multiple stages of the gate driver circuit, thereby reducing DC gate bias stress and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the display panel is divided into multiple blocks with fixed touch sensing periods between display periods, then touch sensing functionality is achieved, but DC gate bias stress concentrates on specific gate driver stages causing line dim phenomena and reduced image quality
Solution Approach 1:
The patent implements dynamic adjustment of the touch sensing period position within the frame period. Instead of fixing the touch sensing period at a predetermined position, the controller shifts the touch sensing period to different positions in successive frames, causing different gate driver stages to experience the touch sensing operations. This dynamic redistribution prevents any single stage from bearing concentrated DC gate bias stress, thereby eliminating line dim phenomena and improving overall image quality.
2Device complexity
If touch sensors are embedded in the pixel array using in-cell touch sensor technology, then touch sensing is integrated without increasing panel thickness, but signal interference and crosstalk occur between pixels and touch sensors
Solution Approach 1:
The patent employs periodic time-division multiplexing to separate pixel driving operations from touch sensing operations. During display periods, pixel circuits are driven normally; during dedicated touch sensing periods, touch sensors are activated. This periodic alternation prevents simultaneous operation of both functions, thereby eliminating signal interference and crosstalk while maintaining the integrated in-cell touch sensor structure.
3Reliability
If the touch sensing period is fixed between display periods, then synchronized operation is achieved, but specific gate driver stages experience repeated DC gate bias stress leading to shortened lifespan
Solution Approach 1:
The patent dynamically shifts the position of the touch sensing period within the frame period across different frames. This causes the burden of DC gate bias stress to rotate among different gate driver stages rather than being permanently assigned to specific stages. Over time, this dynamic redistribution equalizes the stress exposure across all stages, preventing premature failure and extending the overall lifespan of the gate driver circuit.
Data Source
AI summary
A display device is provided that includes a display panel divided into a plurality of blocks, each of the blocks including a plurality of lines of pixels and configured to be driven in a time-division manner with a touch sensing period interposed between two display periods, the two display periods corresponding to display periods for two adjacent blocks of the plurality of blocks. The display device further includes a display driving circuit, and a touch sensing unit configured to receive a sync signal for synchronizing the display driving circuit with the touch sensing unit. The display device is configured to change the sync signal every predetermined period of time so as to shift the touch sensing period interposed between the two display periods.