Deflectometry System for Complex Freeform Surface Metrology
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Solution Overview
Problem
Current deflectometry techniques are limited in measuring complex and discontinuous freeform surfaces due to their inability to accurately capture local slopes and 3D shapes, and require complex setups or movement of components.
Innovation Solution
A compact and simple deflectometry system is developed, utilizing two display panels and multiple micro-cameras to provide structured illumination and capture reflected light, allowing for accurate measurement of complex and discontinuous surfaces without the need for component movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional deflectometry techniques are used to measure specular surfaces, then measurement capability is provided, but inability to measure discontinuous surfaces occurs
Solution Approach 1:
The patent divides the measurement task into multiple segments by using multiple cameras positioned at different locations. Each camera captures reflected light from different regions of the object, including discontinuous surfaces. The measurement data from multiple cameras are then integrated to achieve complete surface characterization, enabling reliable measurement of discontinuous surfaces that single-camera systems cannot capture.
Solution Approach 2:
The patent transitions from traditional single-plane deflectometry to a multi-dimensional measurement system by positioning cameras at multiple spatial locations and angles. This dimensional expansion allows the system to capture reflected light from complex geometries and discontinuous surfaces, providing comprehensive surface measurement capability that overcomes the limitations of conventional two-dimensional deflectometry approaches.
2Measurement precision
If interferometric methods are used to achieve nanometer accuracy, then measurement precision is improved, but dynamic range becomes quite small
Solution Approach 1:
The patent creates a universal measurement system that can handle multiple measurement scenarios within a single setup. By using multiple cameras with different fields of view and positioning capabilities, the system achieves both high precision measurement of fine surface features and large dynamic range for complex geometries. This multi-functional approach eliminates the need for separate measurement systems for different measurement ranges.
Solution Approach 2:
The patent introduces dynamic measurement capabilities by enabling the system to adaptively select and combine data from multiple cameras based on the specific measurement requirements. The system can dynamically adjust measurement parameters, camera selection, and processing algorithms to optimize both precision and dynamic range for different surface types and measurement conditions.
3Measurement precision
If interferometric testing is implemented to achieve high accuracy, then measurement precision is improved, but system complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical interferometric systems with an optical deflectometry system based on light reflection principles. Instead of using intricate interferometer optics requiring precise mechanical alignment, the system uses standard cameras and simple optical paths that naturally achieve high measurement precision through computational methods. This substitution dramatically reduces system complexity while maintaining or improving measurement accuracy.
Solution Approach 2:
The patent uses digital copying and computational reconstruction methods to achieve high measurement precision. Instead of relying on complex physical optics, the system captures reflected light patterns with simple cameras and reconstructs surface geometry through image processing algorithms. This digital approach eliminates the need for expensive, complex optical components and their precise mechanical adjustment.
4Device complexity
If current deflectometry techniques are used, then simple setup is provided, but inability to measure complex freeform surfaces occurs
Solution Approach 1:
The patent segments the measurement system into multiple independent camera units, each capable of capturing specific regions of complex freeform surfaces. This segmentation allows the system to maintain simple individual camera setups while achieving complex surface measurement capability through the combination of multiple views. Each camera remains simple to operate, but collectively they provide comprehensive measurement of complex geometries.
Solution Approach 2:
The patent extends the measurement capability to complex freeform surfaces by adding spatial dimensions through multiple camera positions and angles. This dimensional expansion transforms a simple two-dimensional measurement system into a multi-dimensional measurement capability that can capture complex three-dimensional surfaces, maintaining operational simplicity while dramatically increasing measurement versatility.
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 effectively measures complex shapes of freeform surfaces, including discontinuous surfaces, with high accuracy and without the complexity or cost of traditional methods, enabling precise surface characterization.
Implementation Method 1
the second panel is configured as a substantially transparent panel that allows the first structured illumination from the first panel to transmit therethrough toward the position of the object
Implementation Method 2
two or more cameras positioned on the second panel; the two or more cameras are positioned to receive reflected light from the object
Data Source
AI summary
Methods, devices and systems describe compact and simple deflectometry configurations that can measure complex shapes of freeform surfaces. One deflectometry system includes a first panel and a second panel positioned at an offset position from each other to provide illumination for an object. The second panel, positioned closer to the object, is operable as a substantially transparent panel, and as a pixelated panel to provide structured light patterns. The system also includes two or more cameras positioned on the second panel an is operable in a first mode where the first panel provides a first structured illumination and the second panel is configured as a substantially transparent panel that allows the first structured illumination from the first panel to transmit toward the object. The system is also operable in a second mode where the second panel is configured to provide a second structured illumination for illuminating the object.