Touch Sensor Dummy Lines for Reduced Electrode Visibility
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Solution Overview
Problem
Current touch sensors face challenges in achieving high sensitivity and optical properties while minimizing optical interference, which degrades image quality in display devices, especially with increasing resolution demands.
Innovation Solution
The implementation of a touch sensor design featuring a substrate with sensing electrodes and dummy lines that match the boundary shape of the electrodes, arranged in specific directions, and including slits to reduce visibility and enhance transmittance, along with bridge electrodes for improved signal speed and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conductive patterns are made visible to improve sensing electrode functionality, then sensitivity is improved, but image quality is degraded
Solution Approach 1:
The dummy line is positioned in the third dimension (above or below the sensing electrode plane) rather than directly on the sensing electrode, allowing it to provide shielding effects without interfering with the optical path. This spatial separation resolves the contradiction by enabling electromagnetic interference protection while maintaining optical transparency.
Solution Approach 2:
The dummy line acts as an intermediary element that provides electromagnetic shielding without directly interfering with the sensing function. It mediates between the need for sensitivity (by not blocking the sensing electrode) and the need to reduce visibility (by providing shielding in a different spatial location).
2Measurement precision
If sensing electrode patterns are increased in density to improve resolution, then measurement precision is improved, but optical interference is increased
Solution Approach 1:
By placing the dummy line in a different spatial dimension (above or below the electrode plane), the invention allows higher density electrode patterns to be used without increasing optical interference. The dummy line provides shielding in the vertical dimension while the electrode patterns maintain their horizontal density for high resolution.
Solution Approach 2:
The dummy line is strategically positioned only in specific regions (above or below the sensing electrode) where it can provide local shielding without affecting the overall optical properties. This localized approach allows high-density patterns to maintain resolution while reducing optical interference in critical areas.
3Object-generated harmful factors
If dummy line is added to reduce electrode visibility, then optical properties are improved, but device complexity is increased
Solution Approach 1:
The dummy line serves multiple functions simultaneously: it provides electromagnetic interference shielding, reduces electrode visibility, and can be integrated with existing electrode patterns. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The dummy line is merged with the existing electrode structure and positioned in the same device layer, combining multiple functions (shielding, visibility reduction) into a single integrated element rather than adding separate components, thus limiting complexity increase.
Data Source
AI summary
A touch sensor includes a substrate layer, a plurality of sensing electrodes on the substrate layer, and a dummy line between the sensing electrodes, the dummy line extending along a boundary of the sensing electrode. Electrode visibility is reduced by the dummy line, and touch sensitivity of the touch sensor is also improved.