Capacitive Touch Panel with Depression Detection for Rain Error Prevention
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Solution Overview
Problem
Electrostatic-capacitance touch panels face challenges in distinguishing between hover operations and water droplet adhesion, leading to erroneous detection of water droplets as hover operations, especially in rainy conditions.
Innovation Solution
An electronic device with an electrostatic-capacitance touch panel and a depression detecting section that validates only the latest pair of two-dimensional coordinates during a predetermined time period after deformation is detected, while ignoring coordinates detected before this time, to differentiate between genuine touch or hover operations and water droplet adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the touch panel detects capacitance changes to identify hover operations, then operation versatility is improved (supporting both bare hand and gloved hand operations), but measurement precision deteriorates (water droplets are erroneously detected as hover operations)
Solution Approach 1:
The detection process is segmented into multiple stages: initial capacitance change detection, subsequent depression detection within a predetermined time period, and final coordinate validation. This multi-stage segmentation allows the system to distinguish between genuine hover operations and water droplet adhesion by requiring both capacitance change and depression detection to validate coordinates.
Solution Approach 2:
Depression detection serves as an intermediary verification mechanism between capacitance change detection and final coordinate validation. The depression detecting section acts as a mediator that confirms whether a detected capacitance change corresponds to a genuine user operation or water droplet adhesion, thereby improving measurement precision while maintaining operation versatility.
2Speed
If all detected coordinates are validated to ensure responsiveness, then operation responsiveness is improved, but reliability deteriorates (erroneous operations from water droplets are executed)
Solution Approach 1:
The system performs preliminary depression detection within a predetermined time period after initial capacitance change detection, before final coordinate validation. This preliminary action filters out erroneous detections from water droplets while maintaining responsiveness to genuine operations by validating coordinates that meet both detection criteria.
Solution Approach 2:
The depression detection result provides feedback to the coordinate validation process. Coordinates are validated only when both capacitance change and depression are detected within the predetermined time period, creating a feedback mechanism that enhances reliability without compromising responsiveness to legitimate user operations.
3Measurement precision
If depression detection is added to distinguish hover operations from water droplet adhesion, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The depression detection function is merged with the existing touch panel structure by integrating the depression detecting section with the touch panel layers. This merging approach enables enhanced detection precision without significantly increasing device complexity, as the depression detection utilizes the existing structural layers and control circuitry.
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 solution effectively prevents erroneous detection of water droplets as operations, ensuring reliable operation with both bare hands and gloved hands by validating only the immediate coordinates after deformation is detected, thereby enhancing the accuracy of touch and hover operations.
Implementation Method 1
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. This change in the lines of electric force appears as a change in electrical charge in reception electrode 102.
Implementation Method 2
the present invention relates to an electronic device provided with a touch panel and also to a coordinate detecting method... an electrostatic-capacitance touch panel, which can receive 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
Data Source
AI summary
An electronic device includes a housing, a display that displays predetermined information, an electrostatic-capacitance touch panel that allows visible light corresponding to display contents of the display to pass through the touch panel, a transparent member that protects the touch panel and that allows the visible light to pass through the transparent member, and a detector that detects deformation of the transparent member. The touch panel detects a pair of two-dimensional coordinates indicated by an indicator, wherein when the touch panel detects a plurality of pairs of two-dimensional coordinates and when the detector detects a predetermined deformation amount; at least one pair of two-dimensional coordinates detected during a predetermined time period prior to a time when the deformation is detected is validated.