OLED TDDI Chip Isolation Pads Reduce Coupling Capacitance
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Solution Overview
Problem
OLED touch and display driver integration chips face interference between display driving pads and touch pads due to adjacent arrangements, leading to reduced Signal-to-Noise Ratio (SNR) and multi-band phenomena, as well as increased load on touch electrodes and data lines caused by coupling capacitance.
Innovation Solution
Incorporating isolation pads between display driving pads and touch pads, connected to lead wires, and applying specific signals or maintaining a floating state to reduce interference and load, thereby improving signal integrity and touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If display driving pads and touch pads are adjacently arranged on the OLED TDDI chip, then integration of touch and display driver is improved, but mutual interference occurs between lead wires causing reduced SNR and multi-band phenomena
Solution Approach 1:
The patent introduces isolation pads as intermediary elements positioned between display driving pads and touch pads. These isolation pads serve as mediators that electrically decouple the two functional groups, preventing mutual interference through their lead wires while maintaining the adjacently arranged integrated structure on the OLED TDDI chip.
Solution Approach 2:
The patent segments the pad array into distinct functional zones by inserting isolation pads between display driving pads and touch pads. This segmentation divides the continuous lead wire paths into separate groups, reducing capacitive coupling and interference between display and touch signal lines while preserving overall integration.
2Device complexity
If display driving pads and touch pads are adjacently arranged on the OLED TDDI chip, then integration of touch and display driver is improved, but coupling capacitance increases causing large load on touch electrodes and data line
Solution Approach 1:
The isolation pads act as intermediary elements that break the direct capacitive coupling between display driving pad lead wires and touch pad lead wires. By inserting these isolation structures, the parasitic coupling capacitance is significantly reduced, thereby decreasing the total load on touch electrodes and data lines while maintaining the integrated chip architecture.
Solution Approach 2:
The patent segments the lead wire routing into separate isolated groups by positioning isolation pads between display and touch pad groups. This segmentation reduces the overlapping area and proximity between lead wires from different functional groups, thereby minimizing coupling capacitance and the associated electrical load.
3Object-affected harmful factors
If time division driving manner is adopted for LCD TDDI chip, then interference between display and touch pads is avoided, but OLED TDDI chip cannot avoid display bright and dark bands problem
Solution Approach 1:
The patent employs isolation pads as intermediary structures that enable simultaneous operation of display and touch functions without mutual interference. Unlike time division driving that sequentially activates display and touch, the isolation pads provide continuous electrical decoupling, allowing overlapping operation periods while preventing interference and avoiding display artifacts like bright and dark bands.
Solution Approach 2:
The patent segments the electrical pathways into isolated groups using isolation pads, enabling independent simultaneous operation of display driving pads and touch pads. This spatial and electrical segmentation removes the need for time division multiplexing, allowing continuous display operation without the bright and dark band artifacts that occur during touch activation in time division schemes.
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 reduces interference and load on touch electrodes and data lines, enhancing the SNR and display quality by isolating the pads and optimizing signal characteristics.
Implementation Method 1
there is a coupling capacitance between a touch pad lead wire and a display driving pad lead wire that are adjacent in the fanout area
Data Source
AI summary
An OLED touch and display driver integration chip is provided, including: a group of display driving pads for providing display driving signals to the OLED touch display panel; a group of touch pads for providing touch driving signals to touch electrodes on the OLED touch display panel and/or receiving touch sensing signals from the touch electrodes, and adjacently arranged with the group of display driving pads; and at least one isolation pad arranged between the group of display driving pads and the group of touch pads.