Dark Field Illuminator Light Pipe for Large Inspection Areas
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Solution Overview
Problem
Existing illumination systems for optical image processing, particularly in large inspection areas, face challenges with uniformity, consistent illumination direction, efficiency, and size, leading to measurement errors and inefficiencies.
Innovation Solution
A light pipe with a reflective sidewall and multiple light sources configured to provide spatially uniform dark field illumination from consistent angles, allowing illumination from all azimuth angles and a selected elevation angle, which is compact and energy-efficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional illumination systems are used for large inspection areas, then the illumination area increases, but illumination uniformity deteriorates
Solution Approach 1:
The illumination system is segmented into multiple independent light pipes, each responsible for illuminating a specific portion of the inspection area. This segmentation allows each light pipe to maintain uniform illumination characteristics while collectively covering a large area, resolving the contradiction between inspection area size and illumination uniformity.
Solution Approach 2:
Each light pipe is designed with specific local optical properties including reflective sidewalls and carefully positioned light sources to achieve optimal illumination uniformity in its local region. The reflective sidewalls redirect light to ensure uniform distribution across the illuminated area, while the local quality of each segment contributes to overall system performance.
2Area of stationary object
If traditional illumination systems are used for large inspection areas, then the inspection area increases, but illumination direction consistency deteriorates
Solution Approach 1:
The system segments the illumination function across multiple light pipes, each maintaining consistent illumination direction characteristics. The reflective sidewalls and light source positioning in each segment ensure that light rays travel in controlled directions, preserving illumination direction consistency across the entire large inspection area.
Solution Approach 2:
The reflective sidewalls act as intermediaries that redirect light from the light sources in a controlled manner. These reflective surfaces ensure that light reaches the inspection area with consistent directional properties, mediating between the light sources and the inspected objects to maintain illumination direction consistency.
3Area of stationary object
If traditional illumination systems are used for large inspection areas, then the coverage area increases, but system efficiency deteriorates
Solution Approach 1:
The reflective sidewalls serve as efficient intermediaries that redirect light multiple times within each light pipe, maximizing the utilization of light from each source. This intermediary mechanism reduces energy loss by ensuring that light is efficiently distributed across the inspection area without requiring excessive light source power.
Solution Approach 2:
The system optimizes illumination parameters including light source positioning, reflective surface angles, and light pipe dimensions to achieve efficient light distribution. By carefully controlling these parameters, the system maximizes illumination efficiency while covering large areas, reducing energy loss through optimized optical path design.
4Area of stationary object
If traditional illumination systems are used for large inspection areas, then the inspection area increases, but illuminator size increases
Solution Approach 1:
The illumination system is divided into multiple compact light pipe segments rather than using a single large illuminator. Each light pipe is a compact unit that can be independently positioned, allowing the system to cover large inspection areas through strategic placement of multiple small units rather than requiring one large illuminator, thus reducing overall system volume.
Solution Approach 2:
The light sources are positioned within the light pipe structures in a nested arrangement, with reflective sidewalls containing and directing light within the pipe boundaries. This nested configuration allows the illumination functionality to be contained within compact light pipe volumes, enabling large area coverage without proportionally increasing illuminator size.
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 solution achieves spatially uniform and consistent illumination across large inspection areas, reducing measurement errors and improving efficiency while maintaining a smaller size compared to traditional solutions.
Implementation Method 1
The light pipe also has at least one reflective sidewall
Data Source
AI summary
An illuminator is described which may be used with large inspection areas and which provides a dark field illumination pattern that is spatially uniform, illuminates from consistent angles, has high efficiency, and is smaller than existing solutions. A light pipe has a first end proximate an object to be illuminated and a second end opposite the first end and spaced from the first end. The light pipe also has at least one reflective sidewall. The first end of the light pipe includes an exit aperture and the second end has at least one opening to allow at least one image acquisition device to view the surface therethrough. At least one light source is configured to provide illumination in the light pipe. The object is illuminated by the first end of the light pipe by illumination at a selected elevation angle and substantially all azimuth angles.