Projected Capacitive Touch Panel Signal Transmission Line Shortening
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Solution Overview
Problem
Conventional projected capacitive touch panels face limitations in size enlargement due to overlong signal transmission lines, which lead to interference and restricted side frame width, hindering the expansion of touch panel size.
Innovation Solution
The implementation of X-axis and Y-axis conversion modules with flexible printed circuit boards and analog-to-digital converters, strategically positioned to shorten signal transmission lines, and a distal control module to process digital signals, reducing interference and allowing for increased touch panel size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the touch panel size is enlarged, then the touch panel area is increased, but the signal transmission lines become overlong and prone to interference
Solution Approach 1:
The patent divides the signal processing function into multiple A/D converters distributed at different locations (first A/D converter near X-axis signal transmission lines, second A/D converter near Y-axis signal transmission lines). This segmentation allows each converter to process signals from nearby electrodes, shortening the transmission distance for each signal path and reducing interference while maintaining the ability to process signals from the entire enlarged touch panel area.
2Device complexity
If the signal transmission lines are concentrated on one side of the touch panel, then the circuit board connection is simplified, but the side frame width cannot be reduced and the transmission lines become overlong
Solution Approach 1:
The patent transitions from concentrating all signal transmission lines on a single side (one-dimensional concentration) to distributing A/D converters at multiple locations around the touch panel (two-dimensional distribution). This dimensional change allows signal lines to be routed to nearby converters rather than all the way to a single concentration point, shortening transmission lengths while maintaining manageable circuit connections through multiple localized interfaces.
3Device complexity
If the A/D converter and controller are mounted adjacent to the signal transmission lines, then the signal processing is simplified, but the touch panel cannot be significantly enlarged due to wiring length limitations
Solution Approach 1:
The patent segments the signal processing architecture by placing multiple A/D converters at different locations around the touch panel rather than using a single centralized converter. Each converter handles signals from its nearby signal transmission lines, enabling the touch panel to be enlarged while keeping individual signal transmission lines short. The segmented architecture maintains simplified signal processing at each location while expanding the overall panel area.
Data Source
AI summary
A projected capacitive touch panel has a substrate, an X-axis electrode layer formed on a top of the substrate and a Y-axis electrode layer formed on a bottom of the substrate. The X-axis and the Y-axis electrode layers respectively have a plurality of X-axis electrodes and Y-axis electrodes arranged in a matrix form and respectively connected with a plurality of X-axis and Y-axis signal transmission lines. Each of the X-axis signal transmission lines and the Y-axis signal transmission lines is connected with a conversion module. The conversion modules is mounted to be adjacent to the X-axis and Y-axis signal transmission lines, converts analog signals into relatively stable digital signals, and transmits the digital signals to an external controller to determine coordinates being touch. Accordingly, lengths of the X-axis and Y-axis signal transmission lines can be shortened and the size of a control area of the touch panel can be enlarged.