Touch Sensor Etching Regions for Moiré Suppression
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Solution Overview
Problem
Touch sensors integrated with display devices often deteriorate image quality due to visible sensing electrodes and moiré patterns caused by overlapping with display panel electrodes, leading to reduced transmittance and user experience.
Innovation Solution
A touch sensor design featuring sensing electrodes with etching regions of specific shapes and tilting angles, which reduce the moiré phenomenon and enhance optical properties by minimizing regular overlapping with display panel pixel structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sensing electrodes are added to the display device, then touch sensing function is improved, but image quality deteriorates due to visible electrodes and moiré patterns
Solution Approach 1:
The sensing electrode is divided into multiple segments with etching regions that create non-uniform patterns. This segmentation prevents the formation of regular overlapping patterns with display pixels, thereby reducing moiré effects while maintaining touch sensing functionality.
Solution Approach 2:
The etching regions are designed with asymmetric shapes and orientations, including inclined patterns at specific angles (15-75 degrees). This asymmetry disrupts the regularity of electrode patterns, preventing moiré pattern formation while preserving the electrode's electrical functionality.
2Area of moving object
If sensing electrodes are made larger to improve touch detection, then sensing area is improved, but transmittance deteriorates due to increased electrode coverage
Solution Approach 1:
The sensing electrode incorporates etching regions that create a porous or perforated structure. This allows light to pass through the electrode areas where etching regions are present, maintaining high transmittance while the overall electrode pattern provides sufficient sensing area through its extended coverage.
3Ease of manufacture
If regular electrode patterns are used, then manufacturing is simplified, but moiré patterns are generated due to overlapping with display pixels
Solution Approach 1:
The etching regions incorporate curved shapes such as sine curves, cosine curves, conic sections, and other curved geometries. These curved patterns disrupt the linear regularity that causes moiré effects, while still allowing for systematic fabrication processes.
Solution Approach 2:
The electrode pattern is modified by adding etching regions that introduce dimensional variations within the electrode layer. This creates a multi-level structure that disrupts planar pattern overlap with display pixels, eliminating moiré while maintaining manufacturing feasibility through standard photolithography processes.
Data Source
AI summary
A touch sensor according to an embodiment of the present invention includes a substrate layer, and sensing electrodes which are disposed on the substrate layer, and have etching regions formed therein in a periodically repeated manner and respectively having a width of 5 to 15 μm. Through the etching regions, transmittance may be improved and optical interference with an image display device may be reduced. The present invention also provides a window stack structure and an image display device including the touch sensor.