Circuit Board Inspection Device for Capacitive Touchscreen Testing
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Solution Overview
Problem
The inspection of capacitive touchscreens requires separate operations for measuring capacitance and resistance, increasing the number of steps and complexity.
Innovation Solution
A circuit board inspection device and method that combines the measurement of capacitance and resistance by using AC voltage output, current detection, and calculating units to determine these values based on current magnitude and phase information, reducing the number of steps and facilitating inspection of capacitive touchscreens with intersecting electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate devices are used for capacitance measurement and resistance measurement, then measurement accuracy is maintained, but the number of inspection steps increases and inspection efficiency decreases
Solution Approach 1:
The patent combines capacitance measurement and resistance measurement into a single integrated inspection process. By applying AC voltage to the electrodes and simultaneously measuring both the current magnitude (for capacitance calculation) and current phase (for resistance calculation), the system eliminates the need for separate measurement operations, thereby reducing inspection steps and improving efficiency
Solution Approach 2:
The inspection device is designed to perform multiple measurement functions using a single setup. The same AC voltage source and current detection system are used to obtain both capacitance and resistance values through different calculation methods based on the measured current characteristics, making the device multi-functional and reducing the need for multiple specialized measurement operations
2Measurement precision
If multiple separate measurement operations are performed, then comprehensive electrical parameters are obtained, but the time required for inspection increases
Solution Approach 1:
The patent implements continuous measurement by performing capacitance and resistance measurements in a single uninterrupted operation. The AC voltage is applied continuously, and both current magnitude and phase are measured simultaneously, allowing both electrical parameters to be obtained in one continuous action rather than through separate sequential measurements that would consume additional time
3Measurement precision
If traditional separate measurement methods are used, then measurement accuracy is maintained, but the risk of electrode damage increases due to repeated connections
Solution Approach 1:
The patent merges capacitance and resistance measurements into a single operation that requires only one connection setup. By simultaneously obtaining both electrical parameters from a single AC voltage application and current measurement, the system minimizes the number of times electrodes need to be connected and disconnected, thereby reducing mechanical stress and the risk of electrode damage
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 simplifies the inspection process by calculating capacitance and resistance values simultaneously, reducing the number of steps and improving accuracy by accounting for internal and stray parameters, while also reducing the risk of electrode damage.
Implementation Method 1
supplying the AC voltage to the second connection terminals by means of the AC voltage output unit and detecting electric current flowing in the first connection terminals by means of the current detection unit
Implementation Method 2
calculating capacitance and resistance values corresponding to each of the combinations based on the magnitude of the currents detected by the current detecting unit in the measuring process and on information indicating the currents' phases
Data Source
AI summary
A measuring process unit for executing a measuring process of, in correspondence with a plurality of combinations obtained by respectively combining a plurality of connection terminals Tx and a plurality of connection terminals Ty, and in respect of the connection terminals Tx, Ty corresponding to each of the combinations, supplying an AC voltage SA to the connection terminals Ty by means of an AC current source 2 and detecting electric current flowing in the connection terminals Tx by means of an ammeter 3, to thereby acquire currents corresponding to each of the combinations; and a calculating unit for executing a calculating process of, based on the size of the currents detected by the ammeter 3 in the measuring process and on information indicating the currents' phases, calculating capacitance and resistance values corresponding to each of the combinations.