Metrology Lighting Configuration for Non-Planar Workpiece Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Precision non-contact metrology systems face limitations in providing uniform and efficient illumination for imaging non-planar workpieces at different focus positions, particularly due to the inefficiencies of conventional lighting configurations such as ring lights, which result in inadequate intensity and non-uniform illumination.
Innovation Solution
A metrology system with a lighting configuration comprising multiple lighting portions, each with an imaging lens portion, is distributed to direct light toward a central volume, providing uniform and dense illumination. This configuration includes a telecentric arrangement and an optical homogenizer to ensure consistent illumination across the X, Y, and Z axes, enabling efficient imaging of non-planar surfaces by controlling light distribution and using pulsed illumination synchronized with focus position modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional lighting configurations (ring light, stage light, coaxial light) are used, then the system structure is simple, but the illumination intensity and uniformity are insufficient for imaging non-planar workpieces at different focus positions
Solution Approach 1:
The lighting system is divided into multiple independent lighting portions (first lighting portion, second lighting portion, etc.) arranged around the optical axis. Each lighting portion contains its own light source and imaging lens portion, allowing independent control and optimization of illumination characteristics for different regions of the workpiece.
Solution Approach 2:
The patent transitions from conventional planar illumination (ring light in one plane) to three-dimensional illumination by arranging lighting portions around the optical axis in multiple dimensions. This creates volumetric illumination that uniformly covers non-planar workpiece surfaces at various focus positions.
2Stability of the object's composition
If conventional lighting configurations are used, then the device complexity is low, but the illumination uniformity across different focus positions is poor
Solution Approach 1:
Each lighting portion is equipped with an imaging lens portion that specifically directs light toward the central volume where the workpiece is positioned. This local optimization ensures that each lighting portion contributes uniformly to the overall illumination, compensating for variations in light paths and achieving consistent illumination uniformity across the entire field of view and at different focus positions.
Solution Approach 2:
The imaging lens portion acts as an intermediary optical element between each light source and the workpiece. It conditions and directs the light from each lighting portion to contribute uniformly to the illumination of the central volume, mediating the light paths to achieve overall illumination uniformity.
3Productivity
If ring light configuration is used, then the structure is simple, but the efficiency of illumination is low due to light loss and non-uniform distribution
Solution Approach 1:
The patent replaces the mechanical ring light structure with an optical system using multiple lighting portions combined with imaging lens portions. This substitution allows for more precise control of light distribution, reducing energy loss and improving illumination efficiency through optimized optical paths.
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 high-efficiency and uniform illumination, allowing for accurate determination of 3D positions of surface points on non-planar workpieces by maintaining consistent intensity across focus positions, enhancing the precision of dimensional measurements and surface inspections.
Implementation Method 1
each lighting portion comprises an imaging lens portion and the lighting portions are distributed in an arrangement in which the imaging lens portion of each lighting portion is configured to direct light toward a central volume
Implementation Method 2
The objective lens has an optical axis and is configured to input image light arising from a workpiece, and to transmit the image light along an imaging optical path
Implementation Method 3
The camera is configured to receive image light transmitted along the imaging optical path and to provide images of the workpiece
Data Source
AI summary
A lighting configuration is provided for utilization with a metrology system. The metrology system includes a camera that provides images of a workpiece at different focus positions (e.g., through operation of a variable focal length lens). The lighting configuration includes a plurality of lighting portions which illuminate the workpiece for the imaging. The lighting portions are distributed in an arrangement (e.g., an annular arrangement) in which an imaging lens portion of each lighting portion directs light toward a central volume (e.g., for which illumination in the central volume may be relatively uniform in X, Y and Z axis directions). Each imaging lens portion may include at least two lenses in a telecentric arrangement. Each lighting portion may comprise an optical homogenizer. The camera acquires a stack of images of the workpiece, from which focus curve data may be determined which indicates 3 dimensional positions of surface points on the workpiece.