Lead Tip Illumination Layout for Accurate PCB Component Detection
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Solution Overview
Problem
Current vision systems in automated electronics assembly systems face challenges in accurately determining the position of component attachment points, particularly due to inadequate illumination that can lead to incorrect orientation and defective printed circuit boards.
Innovation Solution
A pick and place machine equipped with a vision system and an illumination device featuring a plurality of light sources that produce light with controlled thickness and angle, non-normal to the direction of the image capture device, ensuring precise illumination of component features without illuminating background elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If normal illumination is used to illuminate component features, then the illumination intensity is sufficient, but stray light illuminates the background causing detection errors
Solution Approach 1:
The illumination device directs light at an oblique angle specifically onto the component features (lead tips) while using baffles to block stray light from reaching the background. This creates localized illumination quality that highlights only the relevant features without illuminating the background, thereby maintaining both sufficient illumination intensity and high detection accuracy.
Solution Approach 2:
The illumination is applied asymmetrically at an oblique angle rather than normally (perpendicularly). This asymmetric illumination direction, combined with strategically positioned baffles, creates a lighting configuration where light reaches the component features from a specific angle while preventing stray light from scattering onto the background, thus improving measurement precision without sacrificing illumination intensity.
2Measurement precision
If oblique angle illumination is used to prevent stray light, then detection accuracy improves, but illumination intensity decreases
Solution Approach 1:
Baffles are introduced as intermediary elements between the light source and the background. These baffles intercept and block stray light that would otherwise travel from the obliquely illuminated features to the background. This intermediary structure allows the system to maintain oblique angle illumination for accurate feature detection while preventing the harmful stray light from reaching the background, thus preserving both detection accuracy and effective illumination intensity.
3Area of stationary object
If multiple light sources are used to improve illumination coverage, then the illumination area increases, but the complexity of the illumination device increases
Solution Approach 1:
Instead of adding multiple light sources in the same plane (which would increase complexity), the invention utilizes the angular dimension by directing illumination from multiple directions at oblique angles. This dimensional approach allows comprehensive coverage of component features from different angles while maintaining a relatively simple illumination device structure, as each light source can be positioned and angled to illuminate specific feature areas effectively.
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 solution enhances the accuracy of feature detection, preventing incorrect placement and ensuring correct orientation of components on printed circuit boards by effectively illuminating only the component features while avoiding stray light that could mislead the vision system.
Implementation Method 1
an illumination device comprising a plurality of light sources each configured to produce light having a controlled thickness and at a controlled angle
Data Source
AI summary
A pick and place machine includes a feeder system configured to feed components to a picking location, a dispensing head configured to pick fed components from the picking location, a vision system configured to detect features of components picked by the dispensing head. The vision system includes an image capture device pointed in a direction. The pick and place machine further includes an illumination device that includes a plurality of light sources each configured to produce light having a controlled thickness and at a controlled angle relative to the direction. The controlled angle is configured to be non-normal with respect to the direction at which the image capture device is pointed.