OLED Panel Shielding Layer for Touch Display Interference
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Solution Overview
Problem
The integration of touch and display driving in OLED panels using time-sharing methods leads to interference issues such as bright and dark bands, display multi-band, gate driver output signal glitches, and touch malfunctions due to the overlap of display driving and touch sensing operations, causing mutual interference between the OLED and touch sensing layers.
Innovation Solution
Incorporating a first shielding layer between the OLED and touch sensing layers, which can be electrically floating or connected to a reference voltage, to block mutual interference and allow simultaneous display driving and touch sensing operations without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time-sharing driving method is used to drive OLED panel, then display driving operation can be performed, but touch sensing operation is suspended causing bright and dark bands
Solution Approach 1:
The patent merges display driving operation and touch sensing operation into a simultaneous dual-mode driving approach. The TDDI chip is configured to perform both display driving and touch sensing operations at the same time, eliminating the need to suspend either operation. This resolves the technical contradiction by combining previously separate operations into a unified simultaneous execution model, preventing bright and dark bands while maintaining display functionality.
2Productivity
If simultaneous display driving operation and touch sensing operation are performed, then both operations can run concurrently, but display multi-band and gate driver output signal glitch occur
Solution Approach 1:
The patent segments the pin assignments into distinct groups: display driving pins (including ELVDD, ELVSS, GIP clock, GIP data, and GIP control pins) and touch sensing pins (including TX/RX differential pairs). This segmentation isolates the signal paths to prevent interference between display and touch operations, resolving the signal stability issues while maintaining simultaneous operation capability.
Solution Approach 2:
The patent introduces an interleaved pin arrangement as an intermediary structure between display and touch circuits. By alternating the placement of display driving pins and touch sensing pins on the TDDI chip, the design creates physical separation and reduces electromagnetic interference, preventing display multi-band and gate driver output signal glitch while enabling concurrent operations.
3Object-affected harmful factors
If display driving pins and touch sensing pins are arranged in interleaving groups, then fan-out impedance is reduced, but mutual interference between adjacent pins occurs causing color shift
Solution Approach 1:
The patent applies local quality differentiation by assigning specific voltage levels and shielding configurations to different pin groups. Display driving pins are provided with appropriate voltage levels and local shielding, while touch sensing pins have different voltage configurations. This localized optimization maintains low fan-out impedance while preventing color shift through differentiated local characteristics.
Solution Approach 2:
The patent implements equipotentiality by providing reference voltage connections and shielding structures for both display and touch pin groups. By maintaining proper reference potentials and reducing potential differences between adjacent interleaved pins, the design minimizes electromagnetic interference and prevents color shift while preserving the low impedance benefit of interleaved arrangement.
4Productivity
If GIP clock signal overlaps with touch sensing signal, then simultaneous operation is achieved, but GIP output signal glitch occurs
Solution Approach 1:
The patent segments the signal paths by providing dedicated GIP clock pins and dedicated touch sensing pins with separate signal routing. This physical segmentation of signal paths prevents the overlap and interference that causes GIP output signal glitch, while the simultaneous operation capability is maintained through independent parallel signal channels.
Data Source
AI summary
An organic light-emitting display (OLED) panel, including an OLED layer, a touch sensing layer, and a shielding layer, is provided. The OLED layer is suitable for displaying an image. The touch sensing layer is suitable for sensing a touch event of the OLED panel. The shielding layer is disposed between the OLED layer and the touch sensing layer. The shielding layer is suitable for blocking a mutual interference between the OLED layer and the touch sensing layer.