Gate Driver Q-Node Reset for Touch Sensing Displays
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Solution Overview
Problem
In touch sensing display devices, Q node holding stress occurs during the touch period due to the non-discharge of pull-up elements, particularly when using oxide transistors, leading to adverse operations.
Innovation Solution
A gate driving circuit design that includes odd and even reset dummy stages to reset Q nodes to a reset level during the touch period, and odd and even set dummy stages to set Q nodes to a set level during alternate display periods, ensuring all Q nodes maintain a reset level during touch sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If time-divisional driving is implemented with display periods and touch periods, then touch sensing function is enabled, but Q node holding stress increases during touch period
Solution Approach 1:
The patent applies preliminary action by resetting Q nodes to a reset level before the touch period begins and maintaining them at this level during the touch period. This preliminary reset action prevents the harmful charging state from developing during touch sensing, thereby enabling touch functionality while avoiding Q node holding stress.
Solution Approach 2:
The patent introduces an intermediary mechanism (the reset circuitry and control logic) that acts as a mediator between the display driving circuit and the touch sensing period. This intermediary actively manages the Q node states during the transition between display and touch periods, preventing direct harmful effects.
2Ease of manufacture
If pull-up element is implemented as oxide transistor, then manufacturing is simplified, but Q node holding stress causes adverse operation
Solution Approach 1:
The patent applies preliminary anti-action by implementing a reset mechanism that counteracts the harmful charging effect before it can cause adverse operations. The reset circuitry actively prevents the oxide transistor pull-up element from accumulating excessive charge during the touch period, thereby maintaining reliability while preserving manufacturing simplicity.
Solution Approach 2:
The patent uses preliminary action by resetting Q nodes before the touch period starts, preventing the harmful charging state from developing in oxide transistor pull-up elements during touch sensing operations.
3Productivity
If Q node is not discharged during touch period, then display driving is maintained, but pull-up element degradation increases
Solution Approach 1:
The patent applies preliminary action by resetting Q nodes to a safe level before the touch period begins, preventing the harmful charging state from developing during touch sensing. This maintains display driving continuity while protecting pull-up elements from degradation.
Solution Approach 2:
The patent converts the potentially harmful charging state during touch periods into a beneficial controlled state by using the reset mechanism. The Q nodes are deliberately set to a reset level during touch periods, transforming what would be a harmful accumulation into a protective measure that extends pull-up element lifetime.
Data Source
AI summary
A gate driving circuit includes a plurality of first odd main stages configured to drive first odd gate lines of a first display block in a first display period, a plurality of second odd main stages configured to drive second odd gate lines of a second display block adjacent to the first display block in a second display period, an odd reset dummy stage configured to reset a Q node included in a first lower-priority operation stage that is relatively late in operation order among the plurality of first odd main stages in the first display period; and an odd set dummy stage configured to set a Q node included in a first higher-priority operation stage that is relatively advanced in operation order among the plurality of second odd main stages in the second display period.