Dynamic Threshold Touch Sensor for Drag Operation Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Capacitive touch sensor devices face erroneous touch-off determinations during drag operations due to variations in capacitance caused by changes in contact pressure and proximity of objects other than the intended pointer, leading to incorrect input detection.
Innovation Solution
A touch sensor device with a signal calculation unit that updates a threshold based on signal changes during a drag operation, using a first threshold for touch-on and touch-off determinations, and a difference calculation unit to determine pointer separation by analyzing signal changes over specific time periods, thereby preventing erroneous touch-off determinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed threshold is used for touch-off determination, then the device structure remains simple, but erroneous touch-off determinations occur during drag operations due to capacitance variations
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed threshold to a dynamic threshold that automatically adjusts based on detected signal characteristics. The threshold calculation unit modifies the touch-off determination threshold according to the rate of change of the detection signal, allowing the system to adapt to varying capacitance conditions during drag operations and prevent erroneous determinations.
Solution Approach 2:
The patent changes the parameter of the determination threshold based on the rate of change of the detection signal. By introducing a variable threshold that depends on the signal's rate of change rather than using a constant value, the system can distinguish between legitimate touch-off events and false signals during drag operations, improving reliability without requiring complex additional hardware.
2Measurement precision
If the threshold is lowered to detect light touches, then sensitivity increases, but false touch-off determinations increase during drag operations
Solution Approach 1:
The patent applies preliminary action by evaluating the rate of change of the detection signal before making a touch-off determination. The threshold calculation unit预先 (in advance) adjusts the threshold based on the signal's rate of change, so that during drag operations when the rate of change is high, a higher threshold is used to prevent false determinations, while during normal touches when the rate of change is low, a lower threshold maintains sensitivity.
Solution Approach 2:
The patent implements feedback by continuously monitoring the rate of change of the detection signal and using this information to dynamically adjust the touch-off determination threshold. This feedback mechanism allows the system to learn from the current signal characteristics and adapt the threshold accordingly, preventing false determinations during drag operations while maintaining accuracy for legitimate touches.
3Reliability
If a high threshold is used for touch-off determination, then false determinations during drag operations are reduced, but legitimate touch-off detections may be missed
Solution Approach 1:
The patent applies dynamics by making the threshold adaptive rather than static. The threshold calculation unit adjusts the touch-off determination threshold based on the rate of change of the detection signal in real-time. During drag operations when the rate of change is high, a higher threshold prevents false determinations, while during normal touch-off events when the rate of change is low, the threshold automatically lowers to ensure accurate detection, thus resolving the contradiction between reducing false determinations and maintaining detection accuracy.
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 effectively reduces erroneous touch-off determinations during drag operations by dynamically adjusting the threshold based on signal changes, ensuring accurate detection of pointer presence and absence.
Implementation Method 1
a touch panel on which a capacitance is formed with a pointer
Data Source
AI summary
A touch sensor device includes: a touch panel on which a capacitance is formed with a pointer; a signal calculation unit calculating a signal output value based on a magnitude of the capacitance; a contact determination unit comparing the signal output value with a threshold and determining whether the pointer has been brought into contact with or separated from the touch panel; and a threshold calculation unit updating a first threshold used for determining whether the pointer has been brought into contact with the touch panel, if an increase of the signal output value is detected during a first unit time within a time period from a determination that the pointer has been brought into contact with the touch panel until a determination that the pointer has been separated from the touch panel.