Circuit Measuring Device Calibration for LCD Testing Accuracy
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Solution Overview
Problem
Conventional measuring devices for liquid crystal display devices require a long time to generate results and often contain errors due to insufficient input power and inaccurate voltage sensing.
Innovation Solution
A circuit measuring device with current sensing circuits, including current-voltage converters and voltage sensing circuits, that provides a common voltage and current source for calibration and measurement modes, allowing for real-time adjustment of tested currents based on calculated differences between sensed and actual data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measuring devices are used for liquid crystal display devices, then the measurement process is simple, but the measurement time is long and the results contain errors due to insufficient input power
Solution Approach 1:
The patent performs calibration measurements before actual product measurements to establish accurate voltage-to-current conversion relationships. The calibration mode pre-determines the characteristics of light-emitting diodes, storing reference data that enables accurate measurements without requiring extended measurement times during actual testing.
Solution Approach 2:
The patent introduces a microcontroller as an intermediary component that manages the complex measurement process. The microcontroller coordinates between the voltage source, current sensing circuits, and data processing, enabling accurate measurements while maintaining simple operation and reducing overall measurement time through efficient control.
2Measurement precision
If multiple voltage sources and current sources are used to improve measurement accuracy, then the measurement precision improves, but the device complexity and hardware requirements increase
Solution Approach 1:
The patent employs a single voltage source that serves multiple functions: it provides calibration voltages during calibration mode and measurement voltages during actual testing. The same voltage source is used for both establishing reference characteristics and performing product measurements, eliminating the need for separate voltage sources and reducing hardware complexity.
Solution Approach 2:
The patent combines the calibration function and measurement function into a single integrated system. The calibration mode and measurement mode share common hardware components including the voltage source, current sensing circuits, and microcontroller, merging multiple functions into one cohesive device that reduces overall complexity while maintaining precision.
3Reliability
If conventional current sensing methods are used, then the device complexity is low, but the measured results contain errors
Solution Approach 1:
The patent performs preliminary calibration to establish accurate current-voltage conversion relationships before actual measurements. By pre-determining the characteristics of light-emitting diodes and storing reference data, the system ensures reliable measurements without requiring complex real-time calculations or additional sensing hardware during actual testing.
Solution Approach 2:
The patent implements a feedback mechanism where the microcontroller processes sensed voltage data, compares it against calibration references, and adjusts measurements accordingly. This feedback loop compensates for variations in light-emitting diode characteristics, ensuring reliable results while using straightforward circuitry rather than complex sensing arrangements.
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 device reduces measurement time, minimizes hardware requirements by eliminating the need for multiple voltage and current sources, and accurately determines if the tested current matches the target current, adjusting it when necessary.
Implementation Method 1
The current-voltage converter converts the calibration current into a calibration voltage in the calibration mode. The current-voltage converter receives a tested current from the tested circuit and converts the tested current into a tested voltage in the measurement mode.
Implementation Method 2
The voltage sensing circuit is configured to sense a voltage between an input terminal of the current-voltage converter and an output terminal of the current-voltage converter to output sensed calibration data in the calibration mode.
Data Source
AI summary
A circuit measuring device and a method thereof are provided. A voltage source supplies a common voltage such that a calibration current having a preset current value flows from a current-voltage converter to a final test machine. The current-voltage converter converts the calibration current into a calibration voltage. At this time, a voltage sensing component senses a voltage between an input terminal and an output terminal of the current-voltage converter to output sensed calibration data. The current-voltage converter converts a tested current outputted by a tested circuit into a tested voltage. At this time, the voltage sensing component senses the voltage between the input terminal and the output terminal of the current-voltage converter to output actual sensed data. When the final test machine determines that a difference between the sensed calibration data and the actual sensed data is larger than a threshold, the tested circuit is adjusted.