OLED Touch Panel Reusing Cathodes for Synchronized Display and Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current OLED display products face challenges in integrating effective touch control with display functionality, particularly in realizing simultaneous control of touch and display operations without compromising the display performance.
Innovation Solution
A touch panel design incorporating cathodes, touch wires, and touch driving chips, along with pixel circuits that reuse cathodes as touch electrodes, allowing for time-division driving to manage both display and touch functions synchronously, thereby eliminating coupling voltage differences and minimizing the influence of coupling capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If cathodes are reused as touch electrodes in OLED display products, then device complexity is reduced and manufacturing cost is lowered, but coupling capacitance effects arise that interfere with touch control performance
Solution Approach 1:
The patent segments the operating time into distinct display stages and touch control stages. During display stages, the cathode functions as a display electrode; during touch control stages, it functions as a touch electrode. This time-division segmentation allows the same physical structure to serve multiple functions without permanent coupling capacitance interference, resolving the contradiction between structural simplicity and touch control reliability.
Solution Approach 2:
The patent implements periodic switching between display operation and touch control operation. By periodically alternating the function of the cathode between display electrode and touch electrode through time-division driving, the system eliminates continuous coupling capacitance effects while maintaining both display quality and touch sensitivity. This periodic action enables reliable touch control performance despite the shared electrode structure.
2Reliability
If time-division driving is used to control both display and touch functions, then synchronized control is achieved and display effect is improved, but the system requires complex driving coordination
Solution Approach 1:
The patent merges the display driving circuit and touch control circuit into a unified system that shares common components including the cathode, pixel circuits, and control signal terminals. By combining these functions and using time-division multiplexing of the same hardware resources, the patent achieves synchronized control of display and touch operations without requiring entirely separate driving systems, thus improving reliability while managing complexity.
Solution Approach 2:
The patent designs the cathode and pixel circuits to serve multiple functions: they act as display electrodes during display stages and as touch electrodes during touch control stages. This multi-functionality allows the same hardware to support both display and touch operations, achieving synchronized control through universal components rather than dedicated separate systems.
3Ease of manufacture
If cathodes serve dual functions as both display and touch electrodes, then manufacturing cost is reduced and process compatibility is improved, but coupling voltage differences affect touch sensitivity
Solution Approach 1:
The patent applies preliminary compensation for coupling voltage differences by introducing compensation signals during touch control stages. Before actual touch measurement, the system pre-compensates for the voltage effects caused by the shared cathode structure, ensuring that touch sensitivity measurements are not degraded by the dual-function electrode design. This preliminary action maintains high touch sensitivity despite the manufacturing advantages of shared electrodes.
Solution Approach 2:
The patent implements feedback mechanisms where the touch driving chip receives feedback signals from the pixel circuits and adjusts touch control signals accordingly. This feedback loop compensates for coupling voltage differences in real-time, maintaining accurate touch sensitivity detection despite the shared electrode structure. The feedback ensures that touch measurement precision is preserved even though the same cathode serves both display and touch functions.
Data Source
AI summary
The present disclosure relates to a touch panel and a touch screen. In the touch panel, the cathode is reused. In the touch control stage, each of the cathodes serves as a touch electrode, and normal display and touch functions of the touch panel can be realized by a time-division driving manner. Specifically, in the display stage, the pixel circuit controls the light emitting state of each pixel point (each pixel point has a light emitting device including a cathode); in the touch control stage, touch control signals are applied onto all control signal terminals of the pixel circuit and the cathodes at the same time. By doing so, on the basis that the touch control function can be realized, the synchronous driving of the touch control electrodes and the electrodes corresponding to the touch control electrodes can be realized.