Capacitive Touch Control Unit Switch Circuit Noise Reduction
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Solution Overview
Problem
Capacitive touch panels face issues with noise-generated errors and increased production costs due to the need for multiple current measurement, filter, and integrating circuits, which also result in a time difference between calculated and real touch coordinates.
Innovation Solution
The implementation of at least one switch circuit on the X and Y axes of the touch panel, along with a control unit that calculates current signals to determine coordinates, reduces the use of redundant circuits and minimizes noise, using sample and hold circuits and a single analogue/digital conversion circuit to enhance noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple current measurement circuits, filter circuits and integrating circuits are used to measure currents through external wires, then the touch coordinate can be determined, but the production cost increases and noise-generated errors occur
Solution Approach 1:
The patent combines multiple separate circuits (current measurement circuits, filter circuits, integrating circuits) into a single integrated controller. The controller performs all functions including current measurement, filtering, integration, and coordinate calculation in one unified device, thereby reducing the total number of discrete components while maintaining measurement precision and reducing noise-generated errors.
2Measurement precision
If multiple current measurement circuits, filter circuits and integrating circuits are used, then the touch coordinate can be determined, but production costs increase
Solution Approach 1:
The patent combines multiple separate circuits (current measurement circuits, filter circuits, integrating circuits) into a single integrated controller. The controller performs all functions including current measurement, filtering, integration, and coordinate calculation in one unified device, thereby reducing the total number of discrete components while maintaining measurement precision and reducing noise-generated errors.
3Measurement precision
If traditional circuit configuration is used to measure current changes, then touch coordinates can be calculated, but time difference between calculated and real coordinates occurs
Solution Approach 1:
The patent implements continuous real-time measurement and calculation of current changes through the integrated controller. The controller continuously monitors currents through all external wires, performs real-time filtering and integration, and immediately calculates touch coordinates without discrete measurement cycles, thereby eliminating time differences between calculated and actual touch positions.
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 solution effectively reduces noise-generated errors and decreases production costs by minimizing the number of circuits required, ensuring accurate and simultaneous current signal measurement for precise touch coordinate determination.
Implementation Method 1
capacitive touch panels having capacitive point-to-touch sensing means for example, all currents passing through a particular touch input location are sensed to determine the location of the touch point
Data Source
AI summary
A noise reducing device for a capacitive touch panel and a method of reducing noise for a capacitive touch panel are disclosed to solve problems related to noise generated by a conventional filter circuit and an integrating circuit or external noise. In the invention, at least one switch circuit is used so that the conventional filter circuit and integrating circuit used in the prior are omitted. Signals output from a current measurement circuit are transmitting to a control unit to calculate the location of a touch point, reducing any noise.