OLED Module Touch Detection Using Electrode Integration
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Solution Overview
Problem
The integration of a touch sensor with an organic electroluminescent device poses challenges due to the interference of the anode, cathode, or metal foil layer with capacitance detection, necessitating a separate touch panel, which hinders device thinning and production efficiency.
Innovation Solution
An organic electroluminescent module is designed with a luminescent-device driving circuit and a touch-position detection circuit, utilizing the lower electrode as a detection electrode to perform capacitive touch detection, allowing for integrated touch functionality without a separate touch sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate touch panel is installed to enable capacitive touch detection on the organic electroluminescent device, then touch detection precision is improved, but device thickness increases and production complexity increases
Solution Approach 1:
The patent merges the touch detection function with the organic electroluminescent device by using the device's existing electrode structure as the detection electrode. The lower electrode serves dual purposes: as part of the luminescence generation structure and as the detection electrode for capacitive touch sensing. This integration eliminates the need for a separate touch panel, thereby reducing device complexity and production steps while maintaining touch detection capability.
Solution Approach 2:
The lower electrode of the organic electroluminescent device is designed to serve multiple functions simultaneously: it acts as an electrical electrode for luminescence generation and as a detection electrode for capacitive touch sensing. This multi-functionality approach allows the same component to fulfill both display and touch interaction roles, reducing the overall number of components needed.
2Reliability
If a separate touch panel is installed to enable capacitive touch detection, then touch detection function is achieved, but device thinning is hindered
Solution Approach 1:
The patent combines the touch detection function within the organic electroluminescent device structure itself, using the lower electrode as the detection electrode. This integration eliminates the need for an additional separate touch panel layer, thereby enabling device thinning while maintaining reliable capacitive touch detection functionality.
3Device complexity
If the lower electrode is used as detection electrode for capacitive touch detection, then device thinning is achieved and production is simplified, but parasitic capacitance interference occurs
Solution Approach 1:
The patent extracts or removes the parasitic capacitance component from the detection circuit by separating the luminescence driving circuit from the touch detection circuit. The lower electrode is electrically connected to the touch detection circuit rather than the luminescence driving circuit during detection, thereby eliminating the parasitic capacitance introduced by the luminescence driving circuit and improving detection precision.
Solution Approach 2:
The patent introduces a switch as an intermediary component to control the electrical connection of the lower electrode. The switch enables dynamic reconfiguration: during touch detection, the lower electrode is connected to the touch detection circuit while disconnected from the luminescence driving circuit, thereby eliminating parasitic capacitance interference. During luminescence operation, the switch reverses the connection. This intermediary switch resolves the conflict between the two functions.
4Ease of operation
If the luminescence driving circuit is connected to the lower electrode during touch detection, then luminescence control is maintained, but parasitic capacitance interferes with detection precision
Solution Approach 1:
The patent employs dynamic switching to change the electrical connection state of the lower electrode based on operational requirements. During touch detection, the switch disconnects the lower electrode from the luminescence driving circuit and connects it to the touch detection circuit, eliminating parasitic capacitance interference. During luminescence operation, the switch reverses the connection. This dynamic reconfiguration allows the system to optimize for either detection precision or luminescence control depending on the current operation mode.
Solution Approach 2:
The patent implements periodic switching between luminescence mode and detection mode. The switch alternately connects the lower electrode to different circuits in synchronization with the operational requirements: during detection periods, the lower electrode is connected to the touch detection circuit; during luminescence periods, it is connected to the luminescence driving circuit. This periodic action ensures that parasitic capacitance only interferes during brief transition periods rather than continuously.
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
This configuration enables thin device designs and reduced production hours by eliminating the need for a separate touch sensor, while enhancing touch-position detection precision by canceling parasitic capacitance and preventing interference from the luminescent-device driving circuit.
Implementation Method 1
an organic electroluminescent device having an organic luminescent functional layer provided between a pair of electrodes
Implementation Method 2
capacitance detection by the sensor electrode
Data Source
AI summary
Provided is an organic electroluminescent module with: an organic electroluminescent device in which an organic luminescent functional layer is provided between a pair of electrodes; a luminescent-device driving circuit unit that is connected to the pair of the electrodes and controls the luminescence of the organic electroluminescent device; and a touch-position detection circuit unit that is connected to both ends of a detection electrode in a touch-position detection direction, which is either of the pair of electrodes, wherein the touch-position detection circuit unit performs the touch-position detection by detecting electrical characteristics at both ends of the detection electrode.