In-cell Touch Water Mode Detection via Dummy Scan Segmentation
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Solution Overview
Problem
Conventional in-cell touch panels fail to accurately detect water touches when combined with a touch medium, leading to incorrect rejection of touch inputs due to their palm rejection function, which is not suitable for water detection mode.
Innovation Solution
The method involves operating normal and dummy touch detection operations on touch detection unit groups to generate first and second detection results, with the common voltage of non-scanned units set to reference ground during the dummy scan, allowing for the generation of a water mode detection result that distinguishes between water and touch medium interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the in-cell touch panel uses palm rejection function to reject large touch areas, then false touches from palms can be rejected, but water touches combined with touch medium cannot be accurately detected
Solution Approach 1:
The touch detection is divided into multiple scan periods (first scan period, second scan period, third scan period) with different detection modes. Normal touch detection operates during first and third scan periods, while water mode detection operates during the second scan period, allowing the system to segment detection functions to resolve the contradiction between palm rejection and water mode detection.
Solution Approach 2:
The system dynamically switches between normal touch detection mode and water mode detection mode based on the scan period. The controller activates different detection algorithms at different times, making the detection system adaptable to different operational requirements and resolving the contradiction between fixed palm rejection behavior and needed water mode detection.
2Area of stationary object
If normal touch detection is performed on all touch detection unit groups during normal scan periods, then comprehensive touch coverage is achieved, but water mode detection accuracy deteriorates
Solution Approach 1:
The touch detection units are divided into first touch detection unit groups (scanned during first and third scan periods) and second touch detection unit groups (scanned during second scan period). This segmentation allows different groups to serve different detection purposes at different times, achieving both comprehensive coverage and precise water mode detection.
Solution Approach 2:
The system employs periodic scanning with alternating patterns: normal scan periods for comprehensive coverage followed by water mode scan periods for precision detection. This periodic switching between detection modes ensures that all areas are covered while maintaining high precision for water touch detection during dedicated water mode scan periods.
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 enables accurate detection of touch points on an in-cell touch panel in water mode, allowing the system to operate normally even when water is present with a touch medium, effectively disabling palm rejection when necessary.
Implementation Method 1
a touch detector... configured to operate a normal touch detection operation... to obtain a first detection result; and operate a dummy touch detection operation
Data Source
AI summary
A water mode detection method includes: operating a normal touch detection operation on each of a plurality of touch detection unit groups during each of a plurality of normal scan periods to obtain a first detection result; operating a dummy touch detection operation on a first touch detection group of the touch detection unit groups to obtain a second detection result during a dummy scan period, and setting a common voltage of a second touch detection group of a plurality of non-scanned touch detection unit groups to a reference ground during the dummy touch detection operation; and generating a water mode detection result according to the first detection result and the second detection result.