Dark Field Illuminator Uniform Intensity LED Segmentation
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Solution Overview
Problem
Existing dark field illumination methods are inefficient in providing uniform illumination over a field of view, especially in machine-vision applications like optical inspection systems for electrical circuits, as they fail to maintain consistent intensity and angular incidence across the inspection area.
Innovation Solution
A dark field illuminator system that includes a light source providing a ring of light with uniform intensity distribution, a collimating ring to direct collimated light beams as identical cones, and a series of reflectors and refracting rings to ensure consistent illumination angles across the inspection area, with all components co-centric to the optical axis, allowing for uniform and efficient dark field illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional dark field illumination methods are used, then uniform illumination can be achieved, but the system becomes very inefficient
Solution Approach 1:
The light source is segmented into multiple independent LED chips arranged in a circular pattern, allowing individual control of each segment to achieve uniform illumination while maintaining high efficiency. This segmentation enables precise control over light distribution without requiring inefficient traditional dark field illumination methods.
Solution Approach 2:
The patent changes the parameters of the light source by using multiple LED chips with adjustable current and voltage, allowing dynamic control of light intensity and distribution. This enables the system to achieve uniform illumination efficiency that traditional methods cannot attain.
2Manufacturing precision
If traditional illumination methods are used, then simple structure can be maintained, but consistent intensity and angular incidence cannot be maintained across the inspection area
Solution Approach 1:
The illumination system is divided into multiple independently controllable LED segments arranged in circles at different heights. Each segment can be controlled to provide consistent intensity and angular incidence, achieving high illumination uniformity across the inspection area while maintaining a modular and manageable structure.
Solution Approach 2:
The patent introduces a vertical dimension by arranging LED chips in multiple circular levels at different heights above the inspection surface. This multi-level arrangement enables precise control over angular incidence and light distribution, achieving consistent illumination without excessive complexity in any single plane.
3Illumination intensity
If multiple LED chips are used to improve illumination uniformity, then illumination consistency improves, but device complexity increases
Solution Approach 1:
Multiple LED chips are merged into circular arrangements that function as integrated illumination units. The circular geometry and coordinated control of chips within each circle allow them to work as a unified system, achieving uniform illumination while reducing the complexity of controlling individual components separately.
Solution Approach 2:
The circular arrangement of LED chips serves multiple functions simultaneously: it provides uniform illumination, controls angular incidence, and enables dynamic intensity adjustment. This multi-functionality reduces the need for separate components, achieving illumination consistency without proportionally increasing device complexity.
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 system achieves uniform illumination both in intensity and angular incidence over a large field of view, enhancing the effectiveness of machine vision applications, particularly in automatic optical inspection of semiconductor wafers and other electrical circuits.
Implementation Method 1
a collimating ring adapted to receive the ring of light and to direct collimated light beams towards an area of an inspected object such that different points within the area are illuminated by light beams that form substantially identical cones of light
Implementation Method 2
a folding ring reflector adapted to receive the ring of light and to direct reflected light beams towards a collimating ring
Implementation Method 3
a refracting ring that alters an angle of incidence of reflected light beams such as to illuminate the different points by substantially identical cones of light characterized by an incidence angle
Data Source
AI summary
A dark field illuminator that includes: (i) a light source adapted to provide ring of light characterized by uniform intensity distribution; (ii) a collimating ring adapted to receive the ring of light and to direct collimated light beams towards an area of an inspected object such that different points within the area are illuminated by identical cones of light characterized by an incidence angle; and wherein the collimating ring and the light source are co-centric to an optical axis of the dark field illuminator.