Coordinate Detecting Device Ghosting Reduction
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Solution Overview
Problem
Existing coordinate detecting devices face challenges in accurately detecting touch positions on a screen due to the 'ghosting phenomenon' when multiple fingers are used, which reduces detection speed and accuracy, and existing methods to mitigate this either slow down the detection process or require excessive scanning operations.
Innovation Solution
A coordinate detecting device that includes a plurality of electrodes arranged in orthogonal directions, a detecting unit to scan these electrodes, and an arithmetic processing unit that identifies peak regions based on sensor output values, selectively detecting sensor output values at intersection points within these peak regions to determine the coordinates of the detection target, thereby reducing the number of scanning operations and enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor output values at all intersection points between electrodes are detected to avoid ghosting phenomenon, then detection accuracy is improved, but the number of scanning operations increases significantly and detection speed is reduced
Solution Approach 1:
The patent applies local quality by making the sensor sensitivity variable across different regions of the touch panel. Specifically, the sensitivity is adjusted based on the position of the detection target, with higher sensitivity applied to regions where ghosting phenomena are less likely to occur and lower sensitivity applied to regions prone to ghosting. This allows accurate detection of touch coordinates without requiring scanning of all intersection points, thus maintaining detection speed while improving accuracy.
Solution Approach 2:
The patent changes the parameter of sensor sensitivity dynamically based on spatial position. By adjusting the sensitivity parameter according to the detected peak regions and their positions, the system can differentiate between actual touch signals and ghosting signals. This parameter change enables the system to achieve high detection accuracy by focusing computational resources only on relevant regions rather than scanning all intersection points uniformly.
2Object-generated harmful factors
If gradient is applied to sensor sensitivity to estimate distance from input side, then ghosting phenomenon is reduced, but detection accuracy deteriorates when touch position is close to ghosting region
Solution Approach 1:
The patent applies preliminary action by first detecting peak regions in the sensor output values before performing coordinate detection. By identifying these peak regions in advance, the system can determine which regions contain actual touch signals versus ghosting signals. This preliminary identification allows the system to focus subsequent detection efforts on valid touch regions, preventing accuracy deterioration near ghosting areas while still effectively suppressing the ghosting phenomenon.
3Adaptability or versatility
If plurality of touch points are detected to enable multi-finger operations, then operational versatility is improved, but ghosting phenomenon increases and complicates gesture determination
Solution Approach 1:
The patent applies segmentation by dividing the touch panel into multiple peak regions based on detected sensor output values. Each peak region corresponds to a distinct touch point, allowing the system to independently process and analyze each touch location. This segmentation enables accurate detection of multiple simultaneous touches while distinguishing them from ghosting signals, thereby maintaining operational versatility without being overwhelmed by ghosting phenomena.
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 allows for high-accuracy detection of touch coordinates with reduced scanning operations, preventing the ghosting phenomenon and maintaining detection speed even when multiple fingers are used, by selectively focusing on sensor output values at intersection points within peak regions.
Implementation Method 1
a device which uses a variation in capacitance formed between an electrode and a portion around the electrode due to the contact of the finger of the user
Data Source
AI summary
A coordinate detecting device includes a plurality of first and second electrodes, a detecting unit for scanning the first and second electrodes to detect sensor output values of the first and second electrodes, and an arithmetic processing unit for performing an arithmetic process on the basis of the detected sensor output values. When there are a plurality of peak regions in which the sensor output values of both the first and second electrodes are equal to or greater than a first threshold value, the detecting unit detects the sensor output values at intersection points between the first and second electrodes in the peak regions. The arithmetic processing unit calculates the coordinates of a detection target on the basis of the sensor output values at the intersection points between the first and second electrodes in the peak regions and the coordinates of the first and second electrodes in the peak regions.