Touch Sensor Controller Frequency Selection for Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensor controllers face challenges in efficiently managing electromagnetic noise levels in transmission signals to touch sensors, leading to potential frequency adjustments that may increase noise levels, thereby affecting detection accuracy and increasing circuit complexity and cost.
Innovation Solution
A sensor controller that includes a transmission circuit to transmit signals in alternating periods for noise measurement and position detection, using a processor to measure noise levels and selectively adjust frequencies based on these measurements to minimize noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor controller analyzes the frequency to analyze the noise components, then the noise components can be detected and analyzed, but the circuit scale and the manufacturing cost increase
Solution Approach 1:
The patent extracts only the necessary noise measurement functionality from full frequency analysis. Instead of implementing a complete frequency analysis circuit, the invention measures noise components at specific frequencies of interest, removing unnecessary circuit complexity while retaining essential noise detection capability
Solution Approach 2:
The patent changes the measurement approach from analyzing all frequency components to measuring only specific frequency parameters. By focusing measurement on predetermined frequencies where noise is most likely to occur, the system achieves effective noise detection without the complexity of broad frequency analysis
2Reliability
If the sensor controller changes the frequency of the transmission signal to another frequency based on frequency analysis at one frequency, then the noise components can be avoided, but the sensor controller may change to a frequency with a high level of noise
Solution Approach 1:
The patent performs preliminary noise measurement at multiple candidate frequencies before making a frequency selection decision. By measuring noise levels at several frequencies in advance and selecting the frequency with the lowest noise, the system ensures reliable operation without the risk of switching to a noisier frequency
Solution Approach 2:
The patent implements a feedback mechanism where noise measurement results from multiple frequencies are continuously monitored and used to dynamically select the optimal transmission frequency. The system measures noise at candidate frequencies, compares the results, and adjusts the transmission frequency based on the measured noise levels, ensuring continuous operation at the least noisy frequency
3Object-affected harmful factors
If the sensor controller measures noise at multiple frequencies and selects the frequency with the lowest noise level, then the electromagnetic noise level can be reduced, but the measurement time and processing complexity increase
Solution Approach 1:
The patent applies partial measurement by selecting and measuring only the most critical frequency points where noise is most likely to occur, rather than measuring all possible frequencies. This selective approach achieves effective noise reduction while minimizing measurement time and processing requirements
Solution Approach 2:
The patent implements periodic frequency switching where the transmission frequency is changed at predetermined intervals based on noise measurements. Instead of continuously measuring and adjusting frequency, the system periodically switches between candidate frequencies, reducing measurement overhead while maintaining noise mitigation effectiveness
Data Source
AI summary
Provided is a sensor controller that controls an operation of a touch sensor that detects a position of a passive pointer. The sensor controller includes a transmission circuit transmitting a transmission signal in a third period at a predetermined cycle, the third period including a first period and a second period, a processor that measures a level of electromagnetic noise at a frequency associated with each period in the first period and the second period, and that selects, as a scan frequency of the transmission signal in the second period, one of a first predetermined number of frequencies and selects, as backup frequencies of the transmission signal in the first period, a second predetermined number of frequencies fewer than the first predetermined number of frequencies different from the scan frequency, in each third period and according to a measurement result.