OLED Touch Sensing Layer Thickness Modification
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Solution Overview
Problem
Existing organic light emitting display devices with integrated touch panels face challenges in maintaining thin thickness while effectively sensing touch position and force, often requiring mechanical elements that increase thickness and complexity.
Innovation Solution
The integration of a touch sensing layer with a first and second touch electrode layer and a thickness modification member between them, along with a touch driving circuit, allows for direct sensing of touch position and force without the need for additional mechanical elements, utilizing amorphous and crystalline transparent conductive materials for efficient capacitance variation detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical element is disposed between the OLED means and a mounting structure to sense force touch, then touch sensing capability is improved, but device thickness increases
Solution Approach 1:
The patent replaces the mechanical element-based force touch sensing system with an electrical field-based capacitive sensing system. The touch sensing layer includes first and second touch electrode layers that form a capacitor, where touch force is detected through capacitance changes rather than mechanical deformation. This substitution eliminates the need for thick mechanical sensing elements while maintaining touch sensing functionality.
Solution Approach 2:
The patent changes the sensing parameter from mechanical displacement to electrical capacitance. By measuring capacitance variations between the first and second touch electrode layers, the system can detect touch force without requiring the physical space needed for traditional mechanical sensing elements, thus reducing device thickness.
2Length of moving object
If multiple touch electrode layers are integrated directly on the encapsulation layer, then device thickness is reduced, but touch sensing accuracy may deteriorate
Solution Approach 1:
The patent introduces a thickness modification member as an intermediary between the first and second touch electrode layers. This member adjusts the spacing between electrodes to optimize capacitance sensitivity, ensuring accurate touch sensing even with the integrated thin-film structure. The thickness modification member acts as a mediator that maintains sensing accuracy while enabling the overall thin profile.
Solution Approach 2:
The patent applies different properties to different parts of the touch sensing structure. The first touch electrode layer uses amorphous transparent conductive material deposited at lower temperature, while the second layer uses crystalline transparent conductive material deposited at higher temperature. This local differentiation optimizes both the electrical performance for sensing accuracy and the thermal compatibility with the OLED structure.
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, efficient touch sensing in organic light emitting display devices, enhancing touch position and force detection accuracy while maintaining a slim form factor, and reducing the risk of damage from external factors like water and oxygen.
Implementation Method 1
a capacitive proximity sensing means that senses a force touch of a user by sensing a variation of a capacitance caused by a user touch
Data Source
AI summary
Disclosed is an organic light emitting display device including an encapsulation layer covering a pixel array layer provided on a substrate and a cover window coupled to a touch sensing layer. The touch sensing layer includes a first touch electrode layer provided on the encapsulation layer, a second touch electrode layer provided on the first touch electrode layer, and a thickness modification member between the first touch electrode layer and the second touch electrode layer.