Touch Panel Controller Dynamic Code Correlation for Distant Detection
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Solution Overview
Problem
Existing touch panel systems face difficulties in accurately detecting touch inputs when the object is positioned slightly away from the surface, as the change in electrostatic capacitances between sense lines and drive lines becomes small, making detection challenging.
Innovation Solution
A touch panel controller that includes a capacitance driving unit to output linear sum signals from sense lines with parallel drive lines, a driving signal generation unit to generate driving signals using code sequences, and a correlation control unit to adjust the correlation of code sequences based on the detection distance between the touch panel surface and the object, allowing for improved detection of touch inputs at varying distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the object is positioned slightly away from the touch panel surface, then the detection range is improved, but the detection accuracy deteriorates because the change in electrostatic capacitances becomes small
Solution Approach 1:
The patent dynamically adjusts the correlation of code sequences based on the detection distance between the touch panel surface and the object. When the object is away from the surface, the system switches to code sequences with higher correlation to enhance signal strength and maintain detection accuracy, thereby resolving the contradiction between extended detection range and preserved detection accuracy.
Solution Approach 2:
The patent changes the parameter of code sequence correlation according to the detection distance. By switching between different correlation levels of code sequences based on the object's position, the system adapts to varying detection conditions and maintains accurate detection whether the object is close to or far from the touch panel surface.
2Power
If code sequences with high correlation are used, then the signal strength is improved for distant objects, but the noise influence increases
Solution Approach 1:
The system dynamically selects code sequences with appropriate correlation levels based on the detection distance. When objects are distant, high-correlation code sequences are used to boost signal strength. When objects are close, low-correlation code sequences are used to minimize noise influence, thus dynamically balancing signal strength and noise rejection.
Solution Approach 2:
The correlation parameter of code sequences is adjusted according to detection conditions. By changing this parameter adaptively, the system optimizes the balance between signal strength and noise influence for different object positions, achieving better overall detection performance.
3Speed
If multiple drive lines are driven in parallel, then the detection speed is improved, but the complexity of the driving signal increases
Solution Approach 1:
The patent uses code sequences (such as M-sequences) to drive multiple lines in parallel in a periodic manner. This allows simultaneous driving of multiple drive lines with structured signal patterns that facilitate later signal processing and capacitance calculation, thereby achieving fast parallel detection while managing signal complexity through regular, repeatable signal structures.
Solution Approach 2:
The system uses the known code sequences as reference signals for correlation computation. By comparing the received signals with the transmitted code sequences, the system can accurately extract capacitance information from parallel drive lines, managing the complexity of parallel driving signals through feedback-based signal processing.
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 configuration enables more accurate detection of touch inputs at positions slightly away from the surface by reducing noise influence and enhancing signal correlation, thereby improving detection accuracy.
Implementation Method 1
a touch panel device which detects distribution of capacitance values of respective electrostatic capacitances of an electrostatic capacitance matrix formed in a vicinity of intersections of M drive lines (M is an integer of 2 or more) and L sense lines (L is an integer of 2 or more)
Implementation Method 2
The differential amplifiers 55 receive linear sum signals X1, X2, X3 and X4 which are output from sense lines having electrostatic capacitances driven by the driving unit 54, and amplifies differences thereof
Data Source
AI summary
Provided is a driving control unit (93) which performs control to switch high and low of correlation of code sequences output by driving signal generation units (4a to 4d) according to a detection distance which is a distance between a surface of a touch panel (2) and an object to be detected.