Single ITO Touch Sensor Index Matching Layer Alignment
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Solution Overview
Problem
Touch sensors with a single ITO layer face challenges in identifying sensor cutting marks and binding regions during the shadow elimination process due to the lack of a metallic layer, making it difficult to align and bind individual sensors accurately.
Innovation Solution
A method involving the formation of an index matching layer with a peelable adhesive on a glass substrate, where portions corresponding to sensor cutting marks and binding regions are partially removed, allowing for the easy identification of these areas during the etching process of the ITO layer, thereby enhancing visibility and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If shadow elimination is performed on a single ITO layer touch sensor, then visual clarity is improved, but sensor cutting marks and binding regions become difficult to identify
Solution Approach 1:
A high-refractive-index marker layer is formed on the glass substrate before the ITO layer is deposited. This preliminary action ensures that cutting marks and binding regions are pre-marked with high visibility, which remains visible even after shadow elimination is performed on the ITO layer, thus solving the identification problem while maintaining visual clarity
Solution Approach 2:
The marker layer uses a high refractive index material that creates a visible contrast difference compared to the surrounding areas. This optical property change allows the marker layer to remain visible after shadow elimination, enabling easy identification of cutting marks and binding regions while maintaining overall visual clarity of the display
2Ease of manufacture
If a single ITO layer is used without metallic layer, then manufacturing cost is reduced and multi-touch capability is achieved, but alignment during cutting and binding becomes difficult
Solution Approach 1:
The marker layer is formed on the glass substrate before ITO deposition, pre-establishing visible reference marks for cutting and binding operations. This preliminary marking ensures precise alignment can be achieved even without metallic layers that would otherwise provide natural contrast for alignment
Solution Approach 2:
The high refractive index marker layer creates visible optical contrast that serves as alignment references during manufacturing processes. This optical contrast enables precise alignment for cutting and binding operations while maintaining the cost-effective single ITO layer structure without metallic layers
3Difficulty of detecting and measuring
If index matching layer is completely removed, then cutting marks and binding regions are highly visible, but visual clarity of the touch sensor is degraded
Solution Approach 1:
The marker layer is selectively removed only at specific locations where cutting marks and binding regions are needed, while the rest of the index matching layer remains intact. This local removal approach provides high visibility at critical areas without degrading the overall visual clarity of the touch sensor
Solution Approach 2:
The index matching layer removal is segmented into specific regions rather than complete removal. The marker layer is removed only at areas requiring cutting marks and binding region visibility, while other areas maintain the index matching layer to preserve visual clarity, thus resolving the contradiction between visibility and visual quality
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
The solution ensures that sensor cutting marks and binding regions can be easily identified and aligned, facilitating accurate cutting and binding of touch sensors with a single ITO layer, improving the manufacturing process and visual clarity.
Implementation Method 1
since a refractive index of the ITO differs largely from that of the glass substrate (the refractive index of the ITO is on the order of 1.9-2.0, while the refractive index of the glass substrate is about 1.52), resulting in a significant difference in the reflectivity between an ITO area and an ITO-free area
Data Source
AI summary
A method for manufacturing a touch sensor having a single ITO layer is disclosed by the invention, including steps of: a) performing cleaning processing on a glass substrate; b) forming an index matching layer on the glass substrate, portions of the index matching layer corresponding to sensor cutting marks and sensor binding regions being at least partially removed, via a peelable adhesive disposed at sites corresponding to the sensor cutting marks and the sensor binding regions on the glass substrate or the index matching layer; c) forming an ITO layer on the partially removed index matching layer; and d) etching the ITO layer so as to form an pattern of the single ITO layer of the touch sensor. A touch sensor having a single ITO layer manufactured by the method and a touch screen including the touch sensor are further disclosed by the invention.