Multi-touch Sensor Coordinate Calculation Using Spatial Frequency Analysis
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Solution Overview
Problem
Existing multi-touch sensors face challenges in accurately determining input points, especially when input points are close together or when using tools like stylus pens, due to limitations in signal separation and coordinate calculation processes.
Innovation Solution
The introduction of a peak analysis processing step within the coordinate calculation procedure, which includes one-dimensional data generation, peak detection, threshold calculation, and spatial frequency distribution analysis, allows for improved separation of adjacent input points and accurate coordinate calculation, even at close distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional coordinate calculation methods are used for multi-touch sensors, then the basic touch detection function is achieved, but the accuracy of coordinate detection deteriorates when input points are close together or when using stylus pens
Solution Approach 1:
The patent segments the detection signal distribution into multiple peaks by analyzing spatial frequency characteristics. By dividing the continuous signal into discrete peak components through frequency domain analysis, the system can accurately identify and separate adjacent input points that would otherwise be merged in conventional methods.
Solution Approach 2:
The patent introduces spatial frequency domain analysis as an additional dimension beyond conventional signal processing. By transforming the detection signal from the spatial domain to the frequency domain and back, the system gains enhanced ability to resolve closely spaced input points without increasing computational complexity.
2Adaptability or versatility
If the number of detectable input points is increased to support multi-touch functions, then the functionality of the touch sensor is improved, but the difficulty of detecting and measuring adjacent input points worsens
Solution Approach 1:
The patent performs preliminary frequency domain analysis on the detection signal distribution before executing the coordinate calculation. By pre-processing the signal to identify peak components in the frequency domain, the system prepares the data structure needed for accurate multi-point separation, making the subsequent coordinate calculation more effective.
Solution Approach 2:
The system uses the spatial frequency distribution as feedback information to guide the peak detection and separation process. The frequency domain characteristics provide feedback about the spatial arrangement of input points, enabling the system to adaptively identify and separate multiple touch points accurately.
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 approach enables highly accurate coordinate calculation for multi-point inputs, regardless of the distance between points, supporting precise input determination with tools like stylus pens and multiple fingers, enhancing performance in devices with complex input requirements.
Implementation Method 1
a capacitive coupling system in which a change in capacitance value is detected
Implementation Method 2
a resistive film system in which a change in resistance value caused by touch is detected
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A sensor apparatus for detecting contact or proximity of an object includes a calculation section for separating a plurality of points of the contact or the proximity that are generated simultaneously, and calculating individual sets of positional coordinates, and the calculation section includes an analysis section for determining, based on a spatial distribution of signal intensity obtained through detection, a condition for separating the spatial distribution of the signal intensity into a plurality of regions.