Touch Screen Reference Value Update for Low Temperature Point Elimination
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Solution Overview
Problem
Capacitive touch screens experience a phenomenon known as 'point elimination' at low temperatures due to temperature drift, where the difference between the reference and sensed values decreases as the touch object heats the screen, leading to incorrect touch coordinate reporting.
Innovation Solution
An update method for the touch screen's reference value is implemented, which involves acquiring environmental temperature, collecting and calculating feature values of continuously touched areas, and updating reference values using these features to maintain a stable difference between reference and sensed values, thereby preventing point elimination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reference value is established before touch detection using code sampling, then the initial state of sensing nodes is captured, but the reference value changes with temperature drift causing point elimination in cold environments
Solution Approach 1:
The patent implements dynamic reference value adjustment by continuously monitoring temperature changes and updating the reference value accordingly. The touch control chip detects temperature variations and adjusts the reference original value in real-time to compensate for thermal drift, transforming the static reference value into a dynamic parameter that adapts to environmental changes.
Solution Approach 2:
The patent changes the reference value parameter based on temperature conditions. When temperature exceeds a threshold or continuous touch is detected, the system updates the reference original value to the current sensed value, effectively changing the reference parameter to match new thermal conditions and prevent measurement errors.
2Reliability
If the finger continuously touches the screen in cold environment, then heat is conducted to the touch screen, but the original value increases causing difference to decrease and point elimination to occur
Solution Approach 1:
The patent implements a feedback mechanism where the touch control chip continuously monitors the sensed values and compares them against the reference value. When the difference between reference and sensed values falls below a threshold (indicating point elimination), the system triggers a reference value update, creating a closed-loop control system that maintains detection reliability.
Solution Approach 2:
The patent performs preliminary reference value updates before point elimination occurs by detecting continuous touch patterns and temperature changes. The system proactively adjusts the reference value when it detects prolonged finger contact in cold environments, preventing the measurement error from developing rather than correcting it after the fact.
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 ensures that the difference between the reference and sensed values does not decrease with temperature rises, effectively preventing point elimination at low temperatures and maintaining accurate touch coordinate reporting.
Implementation Method 1
The capacitive touch screen detects a user's touch operation through a capacitive sensor... the capacitance of a sensing node at a corresponding position will be changed
Implementation Method 2
the temperature of the position will gradually be increased due to the heat conducted by the finger
Data Source
AI summary
An electronic device, a touch detection circuit and an update method for a reference value of a touch screen are provided. The update method includes: acquiring a temperature value of an environment of the touch screen; when determining that the acquired temperature value is less than a preset temperature threshold and determining that a continuously touched area exists in the touch screen, collecting N data frames of the continuously touched area; calculating N feature values of the N data frames; and updating N reference values corresponding to the N data frames according to the N feature values; wherein, N is greater than 1 and N is an integer. A difference between a reference value and a sensed value of the continuously touched area may not be decreased with a temperature rise due to the heat transferred by a touched object, thus point elimination at a low temperature is avoided.