Single-Layer Capacitive Touch Panel Design for Insulator-Free Manufacturing
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Solution Overview
Problem
Capacitive touch panels require insulators between conductive lines of different directions, which affects manufacturing complexity and panel speed, especially as panel size increases.
Innovation Solution
Designing a touch panel with all electrodes on the same layer, utilizing self-capacitance and mutual capacitance to determine touch locations, and adjusting electrode dimensions for optimal signal-to-noise ratio by varying the frequency of the input signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulators are added between conductive lines of different directions, then manufacturing complexity increases and panel speed decreases, but touch detection functionality is maintained
Solution Approach 1:
The patent removes the insulator layer from the traditional capacitive touch panel structure. By eliminating the insulator between orthogonal conductive lines, the device complexity and manufacturing steps are reduced while touch detection functionality is maintained through alternative electrode configuration and signal processing methods
2Reliability
If insulators are added between conductive lines of different directions, then manufacturing complexity increases and panel speed decreases, but electrical insulation is maintained
Solution Approach 1:
The insulator layer is completely removed from the structure. Electrical insulation is no longer provided by a separate insulator layer but is achieved through the spatial arrangement of electrodes, timing of signal application, and signal processing techniques that prevent cross-talk between orthogonal conductive lines
Solution Approach 2:
The patent employs dynamic signal application where electrodes are activated in sequential time slots rather than simultaneously. This temporal separation dynamic approach prevents electrical interference between orthogonal lines without requiring physical insulators, thereby maintaining insulation while enabling faster panel response
3Area of stationary object
If panel size increases, then coverage area increases but panel speed decreases due to charging time
Solution Approach 1:
The large panel is divided into multiple smaller electrode segments arranged in orthogonal grids. Each segment can be independently activated and measured, allowing parallel processing of multiple touch zones simultaneously. This segmentation enables large panel coverage while maintaining fast response times by reducing the capacitance charging time for each individual segment
4Ease of manufacture
If all electrodes are placed on the same layer, then manufacturing complexity decreases, but electrode insulation becomes more difficult
Solution Approach 1:
The patent uses dynamic time-division multiplexing where electrodes on the same layer are activated in sequential time slots. During each time slot, only specific electrode pairs are active, preventing simultaneous current flow between orthogonal electrodes. This temporal separation provides effective electrical insulation without requiring physical barriers, enabling simple single-layer manufacturing while maintaining reliability
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
Eliminates the need for insulators, maintains panel speed regardless of size, and enhances touch detection accuracy and speed by maximizing signal-to-noise ratio.
Implementation Method 1
Multiple touch projective capacitive touch panels detect the change in current or voltage due to change in capacitance when an object touches the touch panel
Implementation Method 2
all electrodes are placed on the same layer of a substrate and self capacitance and mutual capacitance between the electrodes and between electrodes and earth are used to determine the location of a touch
Implementation Method 3
self capacitance and mutual capacitance between the electrodes and between electrodes and earth are used to determine the location of a touch
Implementation Method 4
When a current is applied to an electrode of a capacitive touch panel all the capacitances on those electrodes are charged and this charging takes some time
Data Source
AI summary
The present invention is a touch detection panel that uses capacitance changes between electrodes and changes thereof to determine a position of touch. The touch panel can be used in commercial applications where using a finger, stylus, or other object is the desired method of interface with an electronic system. The touch panel includes conductive electrodes and conductive lines connecting the conductive electrodes. The conductive electrodes themselves can be made of opaque conductive material, substantially transparent conductive material, or transparent conductive material depending on the requirements of an application. The Touch panel is connected to a controller that applies current and/or voltage to the touch panel and senses current and/or voltage from the touch panel to determine either single or multiple touch locations.