Touch Screen Pen Detection With Region-Specific Sensitivity And Palm Rejection
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Solution Overview
Problem
Conventional capacitive writing devices face challenges with large pen heads blocking the view and misjudging palm touches as pen locations, leading to writing inaccuracies and palm rejection issues when the pen temporarily moves away from the touch screen.
Innovation Solution
A detection system for touch screens that records the location of a pen and ignores other objects within a predetermined area, setting a flag to true when the pen is detected and false when it is not, ensuring only the pen's location is provided, even if it temporarily leaves the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pen head area is made large to ensure sufficient capacitive coupling signal, then the detection reliability is improved, but the pen head blocks the user's view and reduces writing precision
Solution Approach 1:
The patent divides the touch screen into multiple detection regions (first region and second region) with different detection sensitivities. The first region uses normal detection for general touch input, while the second region uses enhanced detection specifically for pen input. This segmentation allows the system to maintain reliable pen detection with a small pen head area while avoiding the view-blocking issue of large pen heads.
2Reliability
If the system switches to hand-detection mode when the pen temporarily moves away from the touch screen, then the palm rejection capability is improved, but the system misjudges palm locations as pen positions causing writing errors
Solution Approach 1:
The patent implements a flag mechanism that is set in advance when pen input is detected in the second region. This flag maintains the pen-input state even when the pen temporarily moves away from the touch screen. The system only switches to hand-detection mode when the flag is reset after a predetermined period without pen detection. This preliminary action prevents premature mode switching and ensures accurate location tracking during temporary pen absences.
3Measurement precision
If the system uses a small pen head area to avoid blocking the user's view, then the writing precision is improved, but the capacitive coupling signal becomes insufficient for reliable detection
Solution Approach 1:
The patent applies different detection qualities to different regions of the touch screen. The second region where pen input occurs has enhanced detection sensitivity and dedicated detection mechanisms, while the first region maintains normal detection settings. This local quality enhancement ensures that even with a small pen head area, the system achieves reliable detection in the specific pen-input zone without compromising overall system performance.
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
Enables accurate writing by maintaining palm rejection during pen movement, preventing misjudgment of palm locations as pen positions and ensuring precise touch detection.
Implementation Method 1
signals from all of the second conductive strips are detected, which represent capacitive coupling signals at the intersections between the first conductive strip provided with the driving signal and all the second conductive strips
Data Source
AI summary
A detection method and device for a touch screen is provided. When a pen touching or approaching the touch screen is detected, only the location of the pen in a predetermined range is provided, and the locations of all other objects within the predetermined range are not provided, such as the location of a palm. Only when the pen is no longer detected over a predetermined period of time, then the locations of objects other than the pen in the predetermined range are provided again.