Row-Based Matrix Sensor Frequency Optimization
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Solution Overview
Problem
Existing input devices using capacitive sensing technologies face limitations in efficiently detecting input objects due to the constraints imposed by the electrical time constants of sensor electrodes, particularly when sensing along columns, where the longest time constant limits the frequency of capacitive sensing signals, leading to reduced accuracy and increased time required for detection.
Innovation Solution
The implementation of a matrix sensor with sensor electrodes arranged in rows on a common surface, where each row has a unique electrical time constant, allowing for the use of different frequencies of capacitive sensing signals based on the row's proximity to the substrate, enabling faster sensing on rows closer to the sensor modules and slower sensing on rows further away, thereby optimizing detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If capacitive sensing signals are sensed along columns using the same frequency for all rows, then the sensing system is simple to implement, but the detection accuracy and speed are limited by the longest time constant in the column
Solution Approach 1:
The patent applies local quality by assigning different frequencies to different rows based on their specific time constants. Each row is configured with a frequency optimized for its distance from the substrate, allowing rows closer to the substrate to use higher frequencies while rows farther away use lower frequencies. This resolves the contradiction by maintaining implementation simplicity through row-based organization while significantly improving detection accuracy through localized frequency optimization.
Solution Approach 2:
The patent changes the frequency parameter dynamically based on row position. By varying the frequency of capacitive sensing signals according to the time constant characteristics of each row, the system optimizes detection performance for each row's specific electrical characteristics. This parameter change enables higher frequencies for rows with shorter time constants (closer to substrate) and lower frequencies for rows with longer time constants (farther from substrate).
2Device complexity
If a single frequency is used for all rows in the sensor array, then the system is easier to control, but the detection time increases due to the longest time constant in the array
Solution Approach 1:
The patent segments the sensor array into multiple rows, each with its own optimized frequency. This segmentation allows independent frequency control for each row based on its time constant characteristics. By dividing the array into rows and applying different frequencies to each segment, the system reduces overall detection time without significantly increasing control complexity, as the frequency assignment follows a systematic pattern based on row position.
Solution Approach 2:
The patent introduces dynamic frequency adjustment based on row position. Instead of using a static single frequency for all rows, the system dynamically selects frequencies that match the time constant characteristics of each row. This dynamic approach optimizes detection speed for each row while maintaining manageable control through systematic frequency assignment based on the row's distance from the substrate.
3Speed
If higher frequency signals are used for rows closer to the substrate, then sensing speed and accuracy improve, but the system must handle varying time constants which increases complexity
Solution Approach 1:
The patent applies local quality by tailoring frequency selection to each row's specific time constant characteristics. Rows closer to the substrate, which have shorter time constants, are assigned higher frequencies to maximize sensing speed. Rows farther from the substrate, with longer time constants, use lower frequencies. This localized optimization improves overall sensing speed while managing complexity through systematic frequency assignment based on spatial position.
4Measurement precision
If row-based sensing with different frequencies is implemented, then detection accuracy and speed improve, but the sensor electrode arrangement and signal processing become more complex
Solution Approach 1:
The patent implements local quality by organizing sensor electrodes into rows with distinct frequency assignments based on their time constant characteristics. This row-based organization with differentiated frequencies significantly improves detection accuracy. The complexity increase is managed by leveraging the natural spatial structure of the sensor array, where rows are already positioned at different distances from the substrate, allowing frequency differentiation to directly reflect physical geometry rather than requiring complex additional 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 approach enhances the accuracy and speed of capacitive sensing by allowing higher frequency signals to be used on rows closer to the sensor modules, reducing overall detection time and improving noise resistance, while maintaining flexibility in sensing order and frequency variation.
Implementation Method 1
the sensor modules are configured to, during a first time period, measure first capacitive sensing signals using a first row of the plurality of rows
Data Source
AI summary
This disclosure generally provides an input device that includes a matrix sensor that includes a plurality of sensor electrodes arranged in rows on a common surface or plane. The input device may include a plurality of sensor modules coupled to the sensor electrodes that measure capacitive sensing signals corresponding to the electrodes. Instead of measuring sensor electrodes that are in the same column, the embodiments herein simultaneously measure capacitive sensing signals on at least two sensor electrodes that are in the same row. In one example, the sensor electrodes in the row being measured are spaced the same distance from a side of a substrate coupling the electrodes to the sensor modules and may have approximately the same electrical time constant.