Transparent Touch Display Electrode Layout for Low-Noise Sensing
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Solution Overview
Problem
Existing touch display devices with integrated touch sensors and self-emissive capabilities, such as OLEDs, face challenges in achieving both high transmittance and accurate touch sensing while maintaining reduced thickness and complexity in the manufacturing process.
Innovation Solution
A transparent touch display device with a touch sensor integrated display panel featuring two or more cathode electrodes separated in a cathode electrode layer, and a touch shield structure to reduce coupling noise between touch lines and display driving patterns, enabling accurate touch sensing and high transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a touch sensor is integrated into a display panel to reduce thickness and improve image quality, then the device thickness is reduced and image quality is improved, but it becomes challenging to satisfy both self-emission characteristics and high transmittance characteristics simultaneously
Solution Approach 1:
The touch sensor electrodes are segmented into multiple regions: a first transparent electrode in the pixel area for self-emission display, and a second transparent electrode in the non-pixel area for touch sensing. This segmentation allows each region to be optimized for its specific function, enabling the display panel to simultaneously achieve both self-emission and high transmittance characteristics.
Solution Approach 2:
Different regions of the display panel are assigned different optical properties: the pixel area maintains self-emission characteristics with appropriate electrode transparency, while the non-pixel area is designed with high transmittance for touch sensing. This local differentiation allows the overall device to satisfy both self-emission and high transmittance requirements.
2Device complexity
If touch electrodes and touch lines are integrated into the display panel, then manufacturing complexity is reduced, but coupling noise between touch lines and display driving patterns increases
Solution Approach 1:
A shield electrode is introduced as an intermediary element between the touch lines and display driving patterns. This shield electrode acts as a mediator that blocks electromagnetic coupling noise while maintaining the integrated structure's manufacturing simplicity. The shield electrode is connected to a reference potential, effectively isolating the touch sensing circuit from display driving interference.
3Quantity of substance
If transparent electrodes are used in the touch sensor, then transmittance is improved, but touch sensing accuracy deteriorates due to increased noise
Solution Approach 1:
The transparent electrodes are segmented into functionally distinct regions: the first transparent electrode in the pixel area optimized for display with appropriate transparency, and the second transparent electrode in the non-pixel area optimized for touch sensing. This segmentation allows the touch sensing region to achieve both high transmittance and low noise by being spatially separated from high-frequency display driving patterns.
Solution Approach 2:
The shield electrode serves as an intermediary that protects the transparent touch sensing electrode from electromagnetic noise generated by display driving patterns. This shielding mechanism maintains the transparency of the touch electrode while improving touch sensing accuracy by reducing noise interference.
Data Source
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AI summary
The present disclosure relates to a transparent touch display device including: a substrate including a pixel area, a first transmission area located on a first side of the pixel area, and a second transmission area located on a second side of the pixel area; a display cathode electrode to which a base voltage for display driving is applied; a first touch cathode electrode located on a first side of the display cathode electrode and including a same material as the display cathode electrode; a second touch cathode electrode located on a second side of the display cathode electrode and including the same material as the display cathode electrode; a first touch bridge that runs across the pixel area and electrically connects the first touch cathode electrode and the second touch cathode electrode; a first touch line intersecting the first touch bridge and electrically connected to at least one of the first touch cathode electrode and the second touch cathode electrode; and a first upper touch shield disposed over the first touch line and overlapped with at least a portion of the first touch line, wherein the first upper touch shield has an equipotential with the first touch line.