3D Optical Inspection of Laser Defects in Transparent Materials
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Solution Overview
Problem
Existing methods for characterizing laser defects in transparent workpieces are destructive, time-consuming, and costly, and they can only sample a small fraction of the total number of damage tracks.
Innovation Solution
A method involving directing light from an illumination source onto a plurality of defects in a transparent workpiece, detecting a scattering image signal using an imaging system at a non-zero imaging angle, and generating a three-dimensional image of the defects based on the scattering signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If destructive sampling methods (dicing and polishing) are used to inspect defects, then measurement precision can be improved, but productivity decreases and loss of time increases
Solution Approach 1:
The patent replaces mechanical destruction (dicing, polishing, ablation) with optical detection methods. Light scattering measurements are taken through the intact glass substrate to characterize defects, eliminating the need for mechanical sample preparation while maintaining defect detection capability
Solution Approach 2:
The patent creates optical copies (images) of the defect characteristics through light scattering measurements. The scattering pattern serves as an optical fingerprint that reproduces defect information without physical contact or destruction of the original sample
2Measurement precision
If destructive sampling methods are used, then measurement precision can be improved, but loss of time increases
Solution Approach 1:
The patent performs defect characterization before the glass substrate undergoes subsequent processing steps. By measuring light scattering through the intact substrate, defect information is obtained in advance, eliminating the need for time-consuming post-processing sample preparation
Solution Approach 2:
The patent replaces time-consuming mechanical operations (dicing, polishing, ablation) with rapid optical measurements. Light scattering detection provides immediate defect information without the sequential mechanical steps required by traditional methods
3Measurement precision
If conventional destructive methods are used, then measurement precision can be improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical sample preparation equipment (dicing saws, polishing machines, ion beam systems) with simpler optical measurement equipment. A light source and detector are sufficient to characterize defects through the intact substrate
Solution Approach 2:
The patent extracts only the necessary information (light scattering characteristics) from the defect without removing any physical material. This selective information extraction eliminates the need for material removal steps while maintaining measurement capability
4Measurement precision
If destructive sampling is used, then measurement precision can be improved, but quantity of substance inspected decreases
Solution Approach 1:
The patent makes the inspection method universal by enabling measurement through the intact substrate without destruction. This allows the same method to be applied to any defect location and orientation in the glass, increasing the fraction of defects that can be inspected compared to targeted sampling
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
This method allows for efficient and non-destructive inspection of defects, enabling the characterization of defects prior to chemical etching and providing feedback for improving the laser processing system.
Implementation Method 1
detecting a scattering image signal from light scattered by the plurality of defects using an imaging system
Data Source
AI summary
A method for inspecting a transparent workpiece comprises: directing light from an illumination source onto a plurality of defects formed in the transparent workpiece, wherein the plurality of defects extends in a defect direction, wherein the transparent workpiece comprises a first surface and a second surface; detecting a scattering image signal from light scattered by the plurality of defects using an imaging system, wherein an imaging axis of the imaging system extends at a non-zero imaging angle relative to the defect direction, wherein entireties of at least a subset of the plurality of defects are within a depth of field of the imaging system; and generating a three-dimensional image of at least one of the plurality of defects based on the scattering signal.