Touch Panel Adhesive Index Matching for Invisible Electrodes
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Solution Overview
Problem
The visibility of the electrode pattern in touch display devices due to differences in reflectivity between patterned and non-patterned regions, degrading the appearance of the device.
Innovation Solution
A touch display device with a first transparent adhesive layer having a refractive index between 1.65 and 1.72, positioned between the touch panel and the display panel, which equalizes the reflectivity of the patterned and non-patterned portions, reducing the visibility of the electrode pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a patterned electrode layer is used for touch sensing, then touch detection function is improved, but the electrode pattern becomes visible and appearance is degraded
Solution Approach 1:
A transparent adhesive layer with refractive index of 1.65-1.72 is introduced between the touch panel and display panel to act as an optical intermediary. This layer matches the refractive index of the electrode material, reducing reflectivity differences between patterned and non-patterned regions, thereby making the electrode pattern invisible while maintaining touch detection function
Solution Approach 2:
The refractive index parameter of the transparent adhesive layer is specifically optimized to be between 1.65 and 1.72, which matches the refractive index of the electrode material. This parameter change equalizes the reflectivity of light between the patterned electrode regions and non-patterned regions, eliminating the visible pattern effect
2Object-affected harmful factors
If multiple optical films are used to reduce electrode pattern visibility, then appearance is improved, but device thickness and weight increase
Solution Approach 1:
The transparent adhesive layer is designed to perform multiple functions simultaneously: it serves as both the bonding adhesive between touch panel and display panel, and as an optical film for refractive index matching. This merging of functions eliminates the need for separate optical films, reducing device thickness and weight while maintaining appearance quality
3Object-affected harmful factors
If multiple optical films are used to reduce electrode pattern visibility, then appearance is improved, but manufacturing complexity increases
Solution Approach 1:
The transparent adhesive layer is designed as a multi-functional component that simultaneously provides bonding adhesion and optical refractive index matching. This universal component replaces multiple specialized films (adhesive film + optical film), simplifying the manufacturing process and reducing assembly steps while achieving the same appearance improvement effect
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 improves the appearance of the touch display device by making the electrode pattern less or completely invisible, while also simplifying manufacturing and reducing the device's thickness and weight by eliminating the need for multiple optical films.
Implementation Method 1
The refractive index of the first transparent adhesive layer is greater than or equal to 1.65 and less than or equal to 1.72, wherein reflectivity of the patterned portion is substantially the same as reflectivity of the non-patterned portion
Data Source
AI summary
A touch display device comprises a touch panel, a display panel and a first transparent adhesive layer. The touch panel includes a first patterned electrode layer including a patterned portion and a non-patterned portion. The first transparent adhesive layer is disposed between the touch panel and the display panel. The refractive index of the first transparent adhesive layer is greater than or equal to 1.65 and less than or equal to 1.72, wherein reflectivity of the patterned portion is substantially the same as the reflectivity of the non-patterned portion.