Programmable Optoelectronic Lighting for Anisotropic Defect Detection
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Solution Overview
Problem
Existing devices for detecting defects and measuring optical properties in optical parts are limited by their rigid configuration, making them unsuitable for a wide range of applications and unable to effectively detect defects that interact anisotropically with light, such as deflecting and diffusing defects, especially on objects with variable surface characteristics.
Innovation Solution
A device with programmable optoelectronic lighting means and an artificial vision system that generates and shifts definition charts with high spatial frequency patterns, allowing for flexible and adaptable lighting configurations to detect and measure optical properties, including the use of a spatial light modulator (SLM) and image processing to combine images and enhance defect detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rigid configuration with fixed lighting and observation geometry is used, then the device structure is simple, but it cannot detect defects with anisotropic light interaction and cannot adapt to objects with variable surface characteristics
Solution Approach 1:
The patent implements dynamic adaptability by making the observation angle variable rather than fixed. The device can change the angle between the observation direction and the surface normal according to the specific defect type and surface characteristics being inspected, allowing the same device to adapt to multiple inspection scenarios without requiring multiple fixed-configuration systems
Solution Approach 2:
The patent changes the geometric parameters of the inspection system, specifically the observation angle relative to the surface normal. By varying this angle dynamically, the system can optimize defect detection for different surface characteristics and defect orientations, transforming a rigid fixed-angle system into a flexible variable-angle system
2Measurement precision
If multiple lighting configurations are used to detect various defect types, then defect detection capability is improved, but the device complexity increases
Solution Approach 1:
The patent employs dynamic lighting control where the illumination geometry can be adjusted in real-time based on the inspection requirements. Rather than having multiple fixed lighting systems operating simultaneously, the device dynamically reconfigures the lighting arrangement to match the specific defect type and surface characteristics, achieving high detection sensitivity with a more manageable system complexity
Solution Approach 2:
The inspection system performs periodic reconfiguration of lighting and observation angles for different defect categories. By cycling through optimized geometric configurations tailored to specific defect types (e.g., scratches, pits, inclusions), the system achieves comprehensive defect detection capability while managing complexity through systematic, repeatable reconfiguration sequences
3Difficulty of detecting and measuring
If the observation angle is fixed perpendicular to the surface, then the device structure is simple, but deflecting defects and diffusing defects cannot be effectively distinguished
Solution Approach 1:
The patent introduces asymmetric observation geometries by allowing the observation direction to be at varying angles relative to the surface normal, rather than always perpendicular. This asymmetric configuration enables the detection system to differentiate between defect types that appear similar under perpendicular observation, as deflecting defects and diffusing defects exhibit different angular scattering patterns
Solution Approach 2:
The patent adds the dimension of angular variation to the observation geometry. By introducing the angle between the observation direction and surface normal as a variable parameter, the system transforms a two-dimensional surface inspection problem into a three-dimensional spatial analysis, enabling better differentiation of defect types through their distinct angular light interaction characteristics
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 device provides precise and flexible detection of various defects and optical properties across a wide range, enabling high-quality defect classification and measurement, even for anisotropic interactions, with adjustable parameters for sensitivity and defect appearance, suitable for the ophthalmic industry.
Implementation Method 1
programmable optoelectronic lighting means... generate and shift definition charts with high spatial frequency patterns
Implementation Method 2
a reflective product is defined a priori as being a product with a surface that reacts to incident light according to the law of specular reflection
Implementation Method 3
measuring the optical properties of such optical parts (for example characteristics of divergence, refraction, transmission factor, power or vergence, curvature, diffusivity, etc.)
Implementation Method 4
image processing to combine images and enhance defect detection sensitivity
Data Source
AI summary
The invention relates to an appliance for measuring or controlling an optical element (3) comprising illumination means (1) and an associated artificial vision system (2), in which the optical element (3) can be inserted between the illumination means (1) and the artificial vision system (2), said illumination means (1) comprising programmable optoelectronic means for producing a luminous background with spatially and temporally variable brightness. The inventive appliance is characterised in that the programmable optoelectronic means are embodied in such a way as to consecutively generate a plurality of mires, each comprising a pattern which is repeated in a contrasted manner on a uniform background with a high spatial frequency of between 0.01 and 100 patterns/mm, or such that two adjacent patterns are separated by an angle between 0.1 and 30 degrees, said angle being measured from the point of the object on which the pattern is observed. Said generated mires are consecutively spatially staggered in such a way that a plurality of images corresponding to the mires is captured by the artificial vision system after reflection or transmission by the optical element (3), and recombined in the form of a single composed image.