Touch Sensing Film With High Sheet Resistance for Multi-Touch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current touch sensitive films face challenges in accurately detecting multiple simultaneous touches and achieving optical transparency while maintaining electrical conductivity, with complex electrode configurations and visibility issues due to high refractive index materials like ITO.
Innovation Solution
A touch sensitive film with a conductive layer having a sheet resistance of 3.0 kΩ or higher, formed from High Aspect Ratio Molecular Structures (HARMS) networks, enabling capacitive and inductive sensing capabilities, and a non-patterned, solid structure for simplified manufacturing and electronics, allowing for multi-touch detection and optical transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional transparent conductive oxides like ITO are used with patterned sensing electrodes, then optical transparency is achieved, but the patterned electrodes become visible due to high refractive index and manufacturing complexity increases
Solution Approach 1:
The invention extracts the patterned electrode structure from the conductive layer, using instead a solid non-patterned conductive layer. The sensing electrodes are formed by routing drive and sense signals to specific contact regions around the sensing area, eliminating the need for complex patterning of the conductive layer itself while maintaining touch sensing functionality.
Solution Approach 2:
Instead of patterning the conductive layer to create sensing electrodes, the invention inverts the approach by using a solid conductive layer and creating electrodes through signal routing to contact regions. This reverses the conventional method and eliminates the visibility and manufacturing issues associated with patterned transparent conductive oxides.
2Measurement precision
If multiple separate sensing electrodes are used to achieve accurate touch location determination, then measurement precision improves, but device complexity and electronics complexity increase
Solution Approach 1:
The solid conductive layer serves multiple functions simultaneously: it provides electrical conduction, acts as the sensing element, and eliminates the need for separate patterned electrodes. The contact regions around the sensing area enable both drive signal input and sense signal output through the same continuous conductive structure, reducing overall device complexity while maintaining measurement precision.
3Reliability
If transparent conductive oxides with high refractive index are used, then electrical conductivity is achieved, but visibility of the touch sensitive film increases
Solution Approach 1:
The invention uses a solid conductive layer that can be made from materials with refractive indices matched to the substrate, creating an optical copy or match that eliminates visibility. The conductive layer is optically matched to the substrate material, making the touch sensitive film invisible while maintaining electrical conductivity through the solid structure.
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 high sheet resistance and HARMS network structure enhance sensitivity and touch location resolution, enabling effective multi-touch detection and optical transparency, simplifying manufacturing and electronics while reducing visibility issues.
Implementation Method 1
Capacitive touch sensing is based on the principle that a touch on a touch sensitive film means, from electrical point of view, coupling an external capacitance to the measurement circuitry to which the touch sensitive film is connected.
Implementation Method 2
the conductive layer comprises a High Aspect Ratio Molecular Structure (HARMS) network
Implementation Method 3
capacitive and inductive sensing capabilities
Data Source
AI summary
A capacitive touch sensitive film comprises a conductive layer having a sensing region. According to the present invention, the sheet resistance of the conductive layer in the sensing region is higher than or equal to 3 kΩ.