Double-Sided PCB Inspection Preventing Light Leakage
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Solution Overview
Problem
Conventional board inspection apparatuses face challenges in achieving accurate and efficient double-sided inspection of printed circuit boards due to light leakage between the surface and rear faces, leading to reduced inspection accuracy and increased inspection time, especially when performing three-dimensional measurements.
Innovation Solution
A board inspection apparatus is designed with separate and independently controlled irradiation and imaging units for both the surface and rear faces, allowing for alternating image acquisition processes while one side's light is stopped, and optimizing the moving paths to overlap inspection periods, thereby preventing light leakage and enhancing inspection speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous light emission on both surface side and rear face side is performed, then inspection speed is improved, but light leakage to the opposite side occurs and inspection accuracy deteriorates
Solution Approach 1:
The patent implements periodic action by alternately emitting light from the surface-side irradiator and rear face-side irradiator in time-division manner. The control unit coordinates the irradiation and imaging processes so that only one side emits light at a time, eliminating light leakage while maintaining high inspection speed through rapid alternation and overlapping operations.
2Measurement precision
If sequential inspection of surface side and rear face side is performed, then light leakage is prevented and inspection accuracy is improved, but inspection time increases
Solution Approach 1:
The patent applies preliminary action by performing the image acquisition process on one side during the moving time period of the inspection units to the other side. This allows overlapping of inspection operations, where the surface-side inspection unit acquires images while the rear face-side inspection unit is moving into position, and vice versa, thereby reducing total inspection time while maintaining sequential light emission for accuracy.
Solution Approach 2:
The patent ensures continuity of useful action by coordinating the movement and inspection processes so that inspection operations continue without idle time. The image acquisition on one side is performed during the movement to the other side, eliminating waiting periods and maintaining continuous productive operation throughout the double-sided inspection process.
3Measurement precision
If three-dimensional measurement by phase shift method is performed, then inspection accuracy is improved, but light leakage from the other face side significantly affects measurement precision
Solution Approach 1:
For three-dimensional measurement by phase shift method, the patent implements periodic action by strictly alternating light emission between surface-side and rear face-side irradiators. This time-division control eliminates light leakage from the opposite side during phase shift measurements, ensuring high measurement precision while maintaining efficient inspection speed through rapid alternation.
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 configuration improves inspection accuracy and significantly increases the speed of double-sided inspections by preventing light leakage and allowing simultaneous image acquisition on both sides, reducing overall inspection time.
Implementation Method 1
a surface-side irradiator configured to irradiate a predetermined inspection area on a surface side of the board with predetermined light; a rear face-side irradiator configured to irradiate a predetermined inspection area on a rear face side of the board with predetermined light
Data Source
AI summary
A board inspection apparatus is disclosed, which includes a surface-side irradiator irradiating a surface of each inspection area of a board, a surface-side camera taking a surface-side image of the surface, a rear face-side irradiator irradiating a rear face of each inspection area, a rear face-side camera taking a rear face-side image of the rear face, and a controller moving the surface-side irradiator and the surface-side camera to a position corresponding to the surface of each inspection area, moving the rear face-side irradiator and the rear face-side camera to a position corresponding to the rear face of each inspection area, and inspecting the surface and the rear face of each inspection area based on the surface-side image and the rear face-side image, respectively.