Touch Pad Charging Calibration Using Reference Capacitance
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Solution Overview
Problem
Current touch pad testing methods fail to calibrate touch pads to meet environmental changes, leading to inconvenience in the usage of electronic devices equipped with these pads.
Innovation Solution
A charging calibration system that uses a reference touch pad with a higher capacitance value than operation touch pads, coupled with a power supply module and statistics module, to repeatedly charge and discharge the reference pad and adjust the operation touch pads' sensitivity by varying the capacitance value based on environmental changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If identical touch pads are used for testing under different environments, then the testing process is simple and consistent, but the calibration cannot meet environmental changes leading to usage inconvenience
Solution Approach 1:
A reference touch pad with known capacitance value is introduced as an intermediary standard for calibration. The reference touch pad serves as a mediator between the testing system and operation touch pads, enabling accurate calibration across different environments without requiring complex environmental adjustments. The reference touch pad's stable capacitance characteristics allow it to function as a reliable calibration benchmark.
Solution Approach 2:
The system changes the capacitance parameter by using a reference touch pad with a known, stable capacitance value that differs from operation touch pads. By measuring the charging/discharging characteristics of the reference touch pad under various environmental conditions, the system establishes calibration parameters that compensate for environmental variations, thereby improving calibration adaptability without increasing overall system complexity.
2Measurement precision
If a reference touch pad with higher capacitance value is used for calibration, then calibration accuracy under environmental changes is improved, but the device complexity increases due to multiple touch pads and measurement modes
Solution Approach 1:
The calibration system is segmented into distinct functional components: a reference touch pad for establishing calibration standards and operation touch pads for actual use. The testing process is divided into reference measurement mode (calibrating the reference touch pad) and calibration mode (applying calibration to operation touch pads). This segmentation allows each component to be optimized independently, improving measurement precision while managing complexity through functional separation.
Solution Approach 2:
The reference touch pad is pre-calibrated with a known capacitance value and used to establish charging/discharging time constants before actual operation touch pad testing. By performing preliminary calibration measurements on the reference touch pad under controlled conditions, the system derives calibration parameters in advance that are then applied to operation touch pads, improving measurement precision without requiring complex real-time adjustments during operation.
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 system effectively calibrates touch pads to adjust sensitivity according to environmental variations, ensuring accurate performance across different conditions.
Implementation Method 1
the touch pad to be tested is generally treated as a capacitor... a power supply module is applied to charge/discharge the touch pad... charge from an initial voltage value to a set voltage value... discharge from the set voltage value back to the initial voltage value
Data Source
AI summary
A method of a charging calibration system is mainly to charge/discharge a reference touch pad, then to compute a reference charging time needed for a number of accumulated reference supply duties to reach a reference charging number, then to base on the reference charging time to charge/discharge one of operation touch pads repeatedly by a calibration supply duty, finally to count a number of the experienced calibration supply duties within the reference charging time. Thereupon, a reference charged number of an individual operation touch pad within the reference charging time can be obtained. Thus, the operation touch pad can adjust the reference charging time to meet various environmental requirements. Also, the reference supply duty is greater than the calibration supply duty.