PMOLED Display Touch Sensing via Time-Sharing Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Passive matrix organic light emitting diode (PMOLED) displays face challenges in implementing a touch function due to residual capacitance between electrode patterns, which affects smooth touch sensing and requires separate touch sensors, making it difficult to achieve both display output and touch sensing effectively.
Innovation Solution
A method involving time-sharing of control periods for bottom and transparent electrode patterns, using a driving node for communication between these patterns and a touch sensing unit, and applying pulse-type driving voltages to reduce the impact of residual capacitance, allowing for integrated display output and touch sensing without separate touch sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate touch sensor is added to PMOLED display, then touch function is implemented, but device complexity increases
Solution Approach 1:
The patent combines the display electrode patterns with touch sensing electrode patterns into a single integrated structure. The same transparent electrode patterns used for display also serve as touch sensing electrodes, eliminating the need for separate touch sensor layers and reducing device complexity while maintaining touch functionality
Solution Approach 2:
The transparent electrode patterns are designed to perform dual functions: displaying images during the display control period and sensing touch inputs during the touch-sensor control period. This multi-functionality allows a single component to replace what would traditionally require separate dedicated elements
2Illumination intensity
If residual capacitance between electrode patterns is present, then display output is maintained, but touch sensing accuracy deteriorates
Solution Approach 1:
The patent employs periodic time-sharing control, alternating between display control periods and touch-sensor control periods. During touch-sensor control periods, pulse-type driving voltages are applied to minimize residual capacitance effects, while during display control periods, normal display operation proceeds. This periodic switching allows both functions to operate optimally at different times
Solution Approach 2:
The patent changes the voltage parameters by applying pulse-type driving voltages with specific characteristics (short duration, high amplitude) during touch sensing periods. This parameter change temporarily reduces the impact of residual capacitance, enabling accurate touch detection without compromising overall display performance
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
Enables effective implementation of a touch function in PMOLED displays by minimizing residual capacitance effects, allowing for simultaneous display output and touch sensing while maintaining the display's performance conditions.
Implementation Method 1
When a voltage is applied to the cathode and the anode, electrons and holes are injected into each electrode and the injected electrons and holes pass through an electron transport layer and a hole transport layer, respectively, to be coupled to each other in the emission layer. A light emitting material of the emission layer is excited by energy due to the coupling and the light is generated when the light emitting material returns from the excited state to a ground state again.
Implementation Method 2
Passive matrix organic light emitting diode (PMOLED) displays face challenges in implementing a touch function due to residual capacitance between electrode patterns
Data Source
AI summary
A method of controlling a PMOLED display, which includes a plurality of lower electrode patterns arranged in parallel, a plurality of transparent electrode patterns arranged in parallel and being perpendicular to the lower electrode patterns, and an organic compound layer interposed between lower electrode patterns and transparent electrode patterns, to perform a display output and touch sensing by time-sharing a control period for the lower electrode patterns and the transparent electrode patterns into a display control period and a touch-sensor control period in every display frame time, including providing a driving node formed on a line for communication between the transparent electrode patterns and a display driving circuit and a touch sensing unit connecting the driving node and a touch sensing circuit; performing the display output by connecting the transparent electrode patterns and the display driving circuit in the display control period; and performing the touch sensing by connecting the transparent electrode patterns and the touch sensing circuit by the touch sensing unit in the touch-sensor control period.