Touch Panel Press Sensing Stage Height Design
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Solution Overview
Problem
Resistive in-cell touch panels face reduced touch sensing efficiency due to polyimide alignment layers, which increase active force requirements.
Innovation Solution
Designing a touch panel with a press sensing stage and spacer where the height difference between the press sensing stage and the alignment layer is greater than 0.05 μm, reducing the thickness of alignment layers and thereby decreasing contact resistance and active force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyimide alignment layers are used to arrange liquid crystal molecules, then liquid crystal alignment is achieved, but touch sensing efficiency is reduced and active force is increased
Solution Approach 1:
The patent applies local quality by creating different height regions in the pixel electrode structure. The press sensing stage is formed at a higher level than the pixel electrode surface, creating a localized height difference. This allows the alignment layer to be thinner or absent in the sensing region while maintaining proper liquid crystal alignment in display regions, thereby reducing contact resistance and active force in the touch sensing area.
2Reliability
If polyimide alignment layers are used to arrange liquid crystal molecules, then liquid crystal alignment is achieved, but active force is increased
Solution Approach 1:
The press sensing stage creates a localized elevated region where the alignment layer thickness is reduced. This local modification decreases the distance between the pixel electrode and the liquid crystal layer in the sensing area, reducing contact resistance and the active force required for touch sensing, while maintaining liquid crystal alignment functionality.
Solution Approach 2:
The patent introduces a vertical dimension (height difference) to the pixel electrode structure by forming the press sensing stage at a higher level. This dimensional change creates a height difference that reduces the thickness of the alignment layer in the sensing region, thereby decreasing active force while preserving alignment functionality through proper structural design.
3Ease of operation
If alignment layer thickness is reduced, then contact resistance is reduced and active force decreases, but liquid crystal alignment may be compromised
Solution Approach 1:
The patent applies local quality by creating different height regions in the pixel electrode structure. The press sensing stage is formed at a higher level than the pixel electrode surface, creating a localized height difference. This allows the alignment layer to be thinner or absent in the sensing region while maintaining proper liquid crystal alignment in display regions, thereby reducing contact resistance and active force in the touch sensing area.
Solution Approach 2:
The press sensing stage acts as an intermediary structure that mediates between the pixel electrode and the liquid crystal layer. By providing this intermediate elevated platform, the structure enables reduced alignment layer thickness and improved touch sensing while maintaining liquid crystal alignment through its geometric design and interaction with the liquid crystal molecules.
Data Source
AI summary
A touch panel is provided. The touch panel having a pixel area and a sensing area includes a first substrate and an opposite second substrate. A press sensing spacer is disposed on the sensing area of the first substrate. A press sensing stage is disposed on the sensing area of the second substrate, corresponding to the press sensing spacer. An alignment layer is disposed over the second substrate, covering the press sensing stage and the pixel area of the second substrate. In an embodiment, the height of the press sensing stage is greater than the height from the surface of the second substrate at the pixel area to the bottom of the alignment layer by at least 0.05 μm.