Pressure Sensor Touch Driver Contradiction Resolution
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Solution Overview
Problem
Existing pressure sensors in display devices struggle to distinguish intended touch inputs from accidental ones and are affected by variations in load resistance between touch cells, leading to inconsistent touch signal generation.
Innovation Solution
A pressure sensor system with touch cells having driving and sensing electrodes on separate substrates, a pressure sensing layer in between, and a touch driver that compares touch pressures across multiple areas, ignoring inputs based on pressure magnitude and distance criteria, and adjusts signal gain based on load resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure sensors are used to detect touch inputs, then touch functionality is enabled, but the sensor cannot distinguish intended touch inputs from accidental ones
Solution Approach 1:
The touch detection function is segmented into multiple independent touch cells arranged in a matrix pattern. Each touch cell independently detects touch pressure at its location. By dividing the detection area into discrete cells, the system can analyze spatial distribution patterns of touch pressure to distinguish between intentional touches (concentrated on specific cells) and accidental touches (diffuse across multiple cells), thereby improving touch input accuracy while filtering out false inputs.
2Area of stationary object
If multiple touch cells are used to improve detection coverage, then touch area increases, but load resistance varies between cells causing inconsistent signal output
Solution Approach 1:
The system dynamically adjusts the gain parameter for each touch cell based on its load resistance characteristics. By measuring or estimating the load resistance of each individual touch cell and applying compensatory gain adjustments, the system equalizes the output signal magnitude across all cells despite variations in their electrical characteristics. This ensures consistent touch signal output throughout the entire detection area, maintaining measurement precision while preserving large detection coverage.
3Measurement precision
If touch pressure magnitude threshold is set low to detect light touches, then sensitivity increases, but accidental touches are more likely to be detected
Solution Approach 1:
The system initially detects all touch pressures above a low threshold to ensure no intentional light touches are missed, then applies a second filtering stage that evaluates the spatial pattern and magnitude distribution across multiple touch cells. Touches that activate only a single cell or show inconsistent pressure distribution are flagged as potential false detections and filtered out, while genuine touches showing coherent spatial patterns are confirmed. This two-stage approach maintains high sensitivity while reducing false detection rates.
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
Accurately differentiates intended touch inputs from accidental ones and maintains consistent touch signal output across varying load resistances, enhancing user input reliability and sensitivity.
Implementation Method 1
a pressure sensing layer interposed between the plurality of driving electrodes and the plurality of sensing electrodes
Data Source
AI summary
A pressure sensor for a display device, includes: a plurality of touch cells having a plurality of driving electrodes disposed on a first substrate, a plurality of sensing electrodes disposed on a second substrate overlapping the first substrate, and a pressure sensing layer interposed between the plurality of driving electrodes and the plurality of sensing electrodes, the driving electrodes and sensing electrodes overlapping each other; and a touch driver to drive the plurality of touch cells and to detect touch pressure of the plurality of touch cells; wherein, when a plurality of touch areas including at least one touch cell are detected, the touch driver is configured to compare magnitude of touch pressures of the plurality of touch areas and to ignore at least one touch input in at least one touch area.