Structured-light modulation analysis technique for contamination and defect detection of specular surfaces and...

Area of Science:

• Optical Engineering
• Surface Metrology
• Industrial Inspection

Background:

• Increasing demands for high surface quality in electronic device optical components.
• Limitations of existing methods in detecting subtle defects and contamination.
• Need for advanced techniques for whole-field inspection.

Purpose of the Study:

• To analyze and establish the mechanisms and mathematical models of Structured-Light Modulation Analysis Technique (SMAT).
• To design and validate a novel transmission system for defect detection using SMAT.
• To compare SMAT's performance against uniform planar illumination for surface inspection.

Main Methods:

• Theoretical analysis based on photometry and optical characteristics of defects.
• Development of a novel transmission system for SMAT.
• Simulations and experimental validation for both reflection and transmission modes.
• Comparative analysis with uniform planar illumination techniques.

Main Results:

• SMAT effectively eliminates ambient light interference, unlike uniform planar illumination.
• Significantly lower modulation values detected at contamination and defect sites.
• Clear distinction of defects and contamination using SMAT, which were indiscernible with uniform illumination.
• Successful whole-field inspection of specular and transparent optical components.

Conclusions:

• SMAT provides a robust and accurate method for detecting surface contamination and defects.
• The developed transmission system enhances SMAT's applicability to transparent objects.
• SMAT is a superior technique for industrial optical component inspection compared to uniform planar illumination.