Integrated Touch Sensor on Flexible Display Substrate
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Solution Overview
Problem
Flexible display devices with touch sensing sensors face challenges such as increased manufacturing costs, thickness, and durability issues due to the separate attachment of touch panels, which can lead to defects and reduced optical characteristics.
Innovation Solution
Integrating a touch sensing sensor directly onto the display device substrate with a touch driving circuit, encapsulation layer, and overlapping touch electrodes to simplify manufacturing and enhance durability, while preventing moisture and impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate touch panel is attached to the flexible display device, then touch sensing functionality is provided, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the touch sensing sensor and display device into a single integrated structure. The touch sensing sensor is formed directly on the flexible substrate in the same manufacturing process as the display device, eliminating the need for separate touch panel attachment. This integration resolves the contradiction by providing touch sensing functionality while simplifying the manufacturing process and reducing complexity.
2Adaptability or versatility
If a separate touch panel is attached to the flexible display device, then touch sensing functionality is provided, but device thickness increases
Solution Approach 1:
The touch sensing sensor and display device are merged into a single integrated structure formed on the same flexible substrate. This eliminates the need for additional layers from separate touch panel attachment, thereby maintaining thin profile while providing touch sensing functionality.
3Adaptability or versatility
If a separate touch panel is attached to the flexible display device, then touch sensing functionality is provided, but optical characteristics deteriorate
Solution Approach 1:
The integrated structure eliminates intermediate interfaces between separate touch panel and display device. The encapsulation layer directly covers the pixel driving circuit and touch sensing sensor are formed on the same substrate, reducing light scattering and reflection at interfaces, thereby maintaining superior optical characteristics including transmittance and reflectance.
4Adaptability or versatility
If a separate touch panel is attached to the flexible display device, then touch sensing functionality is provided, but durability deteriorates when bent
Solution Approach 1:
The touch sensing sensor and display device are formed as an integrated flexible structure on the same substrate. This unified construction eliminates interface delamination risks and ensures consistent mechanical properties throughout, maintaining durability and reliability when the device is bent or flexed.
5Quantity of substance
If metal electrodes are used in the touch sensing sensor, then electrical conductivity is provided, but corrosion occurs cutting off wires
Solution Approach 1:
The patent employs a composite electrode structure consisting of multiple layers including calcium, aluminum, and lithium fluoride. This composite material configuration provides the necessary electrical conductivity while the lithium fluoride layer protects against corrosion, thereby maintaining wire connectivity and reliability.
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 approach simplifies the manufacturing process, reduces device thickness, improves optical characteristics, and enhances durability by integrating touch sensing functionality directly into the display device, reducing defects and maintaining performance when bent.
Implementation Method 1
The capacitive type of touch sensing sensor includes a sensing capacitor including a plurality of sensing electrodes for transmitting a detection signal, and detects a change in capacitance of the sensing capacitor and/or an amount of charges that is caused when a conductor such as a finger approaches the touch sensing sensor
Data Source
AI summary
A display device includes: a substrate; a pixel driving circuit disposed in a first region on the substrate; an encapsulation layer disposed on the pixel driving circuit; a touch sensing layer formed on the encapsulation layer and including a touch sensing sensor; and a touch-driving layer including a touch driving circuit disposed in a second region on the substrate, integrally formed with the pixel driving circuit, and electrically connected to the touch sensing sensor to apply a signal thereto.