Multi-Touch Detection Using Anisotropic Conductive Films
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Solution Overview
Problem
Conventional resistive touch panels cannot support multi-touch detection, and while capacitive type touch panels can, the methods for determining multiple touched points are complex, lacking simplicity and efficiency.
Innovation Solution
A multi-touch detecting method utilizing two conductive films with electric anisotropy, where the first film has lower resistivity in one direction and the second in a perpendicular direction, allowing for accurate detection of touched points by measuring voltage changes across these films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional capacitive type touch panels are used to support multi-touch detection, then multi-touch capability is achieved, but the detection method becomes complicated
Solution Approach 1:
The touch panel is divided into two separate conductive films (first and second conductive films) with different orientations of electric anisotropy. Each film independently detects touch information in specific directions, and the controller processes their combined data to determine multiple touched points. This segmentation simplifies the detection method while maintaining multi-touch capability.
Solution Approach 2:
Each conductive film is designed with specific local properties: the first conductive film has lower resistivity in the first direction, while the second conductive film has lower resistivity in the second direction. This local quality differentiation enables simple voltage measurements to reveal touch locations in different orientations, simplifying the overall detection process.
2Device complexity
If conventional resistive type touch panels are used, then the structure is simple, but multi-touch detection cannot be supported
Solution Approach 1:
The touch panel uses a composite structure of two conductive films with different electric anisotropy orientations. This composite design maintains structural simplicity similar to conventional resistive panels while enabling multi-touch detection capability through the combined information from both films.
Solution Approach 2:
The two conductive films work together to provide multiple functions: each film can independently detect touch pressure and location in its preferred direction, and their combination enables full multi-touch detection capability. This multi-functionality is achieved within a simple layered 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
This method simplifies the detection of multiple touched points on a touch panel, improving accuracy and enabling intuitive multi-touch functions like zoom, translation, and rotation with a straightforward structure and signal processing.
Implementation Method 1
The first conductive film exhibits electric anisotropy, and has a lower resistivity in a first direction
Implementation Method 2
The second conductive film exhibits electric anisotropy, and has a lower resistivity in a second direction perpendicular to the first direction
Implementation Method 3
first and second conductive films insulated from each other and coupled electrically to each other through touch
Data Source
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AI summary
A multi-touch detecting method is adapted for detecting touched points on a touch panel that includes first and second conductive films (113, 123). The first conductive film (113) exhibits electric anisotropy, and has a lower resistivity in a first direction. The multi-touch detecting method includes: applying a first voltage (Va) to the first conductive film; applying a second voltage (Vb) greater than the first voltage to the second conductive film; measuring sequentially voltages at different measuring points (Xu) of the first conductive film; obtaining a first local maximum voltage, a second local maximum voltage and a local minimum voltage from the measured voltages; determining a first location (Xa) of the touched points based on a location of the measuring point (Xn)corresponding to the first local maximum voltage; and determining a second location (Xb) of the touched points based on a location of the measuring point (Xm) corresponding to the second local maximum voltage.