Touch Panel Deformation Detection for Water Droplet Interference
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Solution Overview
Problem
Electrostatic-capacitance touch panels face erroneous detection issues when a water droplet adheres to the panel, as the change in capacitance value is similar to that of a hover operation, leading to incorrect identification of water droplet adhesion as hover operation, especially in rainy conditions or with a hand wearing a glove.
Innovation Solution
An electronic device with an electrostatic-capacitance touch panel and a depression detecting section that uses a transparent member to differentiate between a water droplet and a finger by detecting deformation, validating coordinates only when a predetermined amount of deformation is detected, ensuring accurate operation without erroneous detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrostatic-capacitance touch panel detects capacitance change to identify hover operation, then hover operation detection capability is improved, but erroneous detection of water droplet adhesion as hover operation occurs
Solution Approach 1:
The patent introduces a depression detecting section as an intermediary component that detects deformation of the transparent member. This mediator distinguishes between genuine hover operations (which cause deformation) and false positives from water droplets (which do not cause deformation), thereby resolving the contradiction between hover detection capability and detection accuracy.
Solution Approach 2:
The patent changes the detection parameter from solely capacitance change to a combination of capacitance change and depression amount. By adding the depression amount parameter, the system can differentiate between hover operations (capacitance change + deformation) and water droplet adhesion (capacitance change only), thus improving reliability while maintaining hover detection capability.
2Speed
If touch panel validates coordinates based on capacitance change alone, then operation response speed is improved, but coordinate validation accuracy deteriorates due to water droplet interference
Solution Approach 1:
The patent performs preliminary depression detection before validating coordinates. The depression detecting section预先 checks for deformation, and only coordinates corresponding to deformed regions are validated. This preliminary action prevents water droplet-induced false coordinates from being validated, improving accuracy without significantly impacting response speed.
3Ease of operation
If touch panel accepts operation with hand in glove through hover detection, then ease of operation in various conditions is improved, but erroneous detection increases due to similar capacitance change pattern
Solution Approach 1:
The depression detecting section serves as an intermediary that verifies genuine user interaction. Since gloved finger hover operations cause deformation while water droplet adhesion does not, the mediator distinguishes between legitimate operations and false positives, maintaining ease of operation with gloves while eliminating erroneous detections.
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
The solution allows for accurate operation without erroneous detection of a bare hand or a hand in a glove, even when a conductive material like a water droplet adheres to the touch panel, by validating coordinates based on deformation, thus preventing misidentification.
Implementation Method 1
an electrostatic-capacitance touch panel, which can accept not only 'touch operation' performed by finger(s) of a bare hand directly touching the surface of the touch panel, but also 'hover operation' performed by the finger at a predetermined height from the surface of the touch panel
Implementation Method 2
A drive pulse is applied to transmission electrode 101 from drive buffer 103 to generate an electric field. When a finger enters this electric field, the number of lines of electric force between transmission electrode 101 and reception electrode 102 decreases.
Implementation Method 3
a depression detecting section that detects deformation of the transparent member
Data Source
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AI summary
Disclosed is an electronic device including: a display section that displays information; an electrostatic-capacitance touch panel layer that allows visible light corresponding to display contents of the display section to pass through the touch panel layer and that determines a two-dimensional coordinate indicated by an indicator having conductivity; glass that protects the touch panel layer and that allows visible light corresponding to display contents of the display section to pass through the glass; a depression sensor that detects deformation of the glass; and a control section that validates a two-dimensional coordinate when a plurality of two-dimensional coordinates are determined by the touch panel layer and when deformation is detected by the depression sensor, the two-dimensional coordinate being determined last among the plurality of two-dimensional coordinates.