Circuit Board Inspecting Apparatus Using Low-Voltage Screening
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Solution Overview
Problem
Existing circuit board inspection methods inaccurately detect insulation failures between wiring patterns, leading to erroneous determination of insulated patterns and potential burnout during high-voltage inspections.
Innovation Solution
A circuit board inspecting apparatus and method that employs a low-voltage inspection to identify potential insulation failures, followed by a resistance measurement to determine the need for a high-voltage inspection, which applies a larger potential difference to accurately detect insulation failures without causing burnout, using a four-terminal measurement method for precise resistance calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high voltage is applied between wiring patterns to detect insulation failures, then the detection capability is improved, but burnout of the portion where insulation failure occurs is caused
Solution Approach 1:
The patent applies a low voltage inspection before the high voltage inspection to preliminarily identify wiring patterns with insulation failures. This preliminary action allows the system to determine which wiring pattern pairs have insulation failures and should not be subjected to high voltage, thereby preventing burnout while maintaining detection capability.
Solution Approach 2:
The patent changes the voltage parameter from low voltage to high voltage in a sequential manner. First, a low voltage is applied to identify insulation failures without causing burnout. Then, based on the low voltage inspection results, a high voltage is applied only to wiring patterns that did not show insulation failures, ensuring both detection accuracy and prevention of damage.
2Object-affected harmful factors
If a low voltage is applied between wiring patterns to avoid burnout, then burnout is prevented, but insulation failures are erroneously determined as favorable insulation
Solution Approach 1:
The low voltage inspection serves as a preliminary screening step to identify wiring patterns with insulation failures. By examining all wiring pattern pairs at low voltage first, the system can distinguish between those with insulation failures and those with favorable insulation, ensuring accurate subsequent high voltage application.
Solution Approach 2:
The low voltage inspection acts as an intermediary step between the wiring patterns and the high voltage inspection. It provides intermediate information about the insulation status of each wiring pattern pair, enabling the system to make informed decisions about which pairs should undergo high voltage inspection and which should be protected from high voltage to avoid burnout.
3Measurement precision
If a high voltage is applied to wiring patterns determined to have no insulation failure at low voltage, then the accuracy of insulation inspection is improved, but the complexity of the inspection process increases
Solution Approach 1:
The low voltage inspection is performed as a preliminary action to simplify the overall process. By identifying and excluding wiring patterns with insulation failures before high voltage application, the system reduces the number of high voltage inspections needed, thereby managing complexity while improving accuracy.
Solution Approach 2:
The inspection process is segmented into two distinct phases: low voltage inspection phase and high voltage inspection phase. This segmentation allows each phase to serve a specific purpose - the low voltage phase identifies insulation failures, and the high voltage phase confirms favorable insulation - making the complex process more manageable and systematic.
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 enhances the accuracy of insulation inspections by reducing the likelihood of incorrectly identifying insulated patterns as failed and preventing burnout, thereby improving the reliability of the inspection process.
Implementation Method 1
a low-voltage inspection part configured to conduct a low-voltage insulation inspection that involves causing a potential difference between the adjacent wiring patterns defined as a wiring pattern pair among the three or more wiring patterns, and determining whether or not an insulation failure occurs between the wiring patterns of each wiring pattern pair, based on a current flowing between the wiring patterns of each wiring pattern pair
Implementation Method 2
a resistance measurement part configured to execute a resistance measurement process that involves measuring a resistance value between the wiring patterns of the wiring pattern pair determined in the low-voltage insulation inspection that the insulation failure occurs
Implementation Method 3
a high-voltage inspection part configured to conduct a high-voltage insulation inspection that involves causing a potential difference, which is larger than the potential difference caused in the low-voltage insulation inspection, between the wiring patterns of the different wiring pattern pair including one of the wiring patterns of the wiring pattern pair having the measured resistance value falling below a preset reference value in the resistance measurement process, the different wiring pattern pair determined in the low-voltage insulation inspection that no insulation failure occurs, and determining whether or not an insulation failure occurs between the wiring patterns of the different wiring pattern pair, based on a current flowing between the wiring patterns of the different wiring pattern pair
Data Source
AI summary
A circuit board inspecting apparatus is disclosed for inspecting a circuit board having wiring patterns separated from each other and forming a plurality of wiring pattern pairs. The apparatus includes a low-voltage inspection part to apply a first low-potential difference below a threshold voltage between wiring patterns in a first of the plurality of wiring pattern pairs, and to detect a first current flowing therebetween. A resistance measurement part is provided to measure a first resistance value between the wiring patterns of the first wiring pattern pair upon detection of the first current and a high-voltage inspection part is configured to selectively apply, based on the first resistance value, a high-potential difference above said threshold voltage, between the wiring patterns in a second of said plurality of wiring pattern pairs.