Subsurface Defect Detection in Optical Components
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Solution Overview
Problem
Current methods for detecting subsurface defects in high-precision optical components are inadequate in terms of nondestructive testing, particularly in positioning, sensitivity, and physical property detection, posing a challenge for quality control and industrial competitiveness.
Innovation Solution
A device and method utilizing a wide-spectrum light source, excitation and detection lasers, dispersion lens set, spectrum detection, and laser interference technology, combined with a motion platform and optical fiber optical path system, to focus lasers at different depths and record ultrasonic vibrations, enabling multi-dimensional defect analysis through spectral confocal technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional subsurface defect detection methods are used, then detection capability is limited, but device complexity and cost increase when improving detection precision
Solution Approach 1:
The detection device is divided into multiple independent functional modules: laser source module, optical path module with adjustable lenses, spectrum analysis module, and data processing module. Each module performs a specific function and can be independently optimized, allowing high detection precision without proportionally increasing overall system complexity.
Solution Approach 2:
The detection device is designed with multi-functionality to detect various types of subsurface defects (cracks, inclusions, voids) across different depth ranges and material types using a single integrated system. The adjustable optical path and multiple detection modes enable one device to replace multiple specialized devices, improving precision without linearly increasing complexity.
2Reliability
If nondestructive testing is implemented for subsurface defects, then quality control improves, but detection sensitivity and physical property detection capability are insufficient
Solution Approach 1:
The device changes detection parameters dynamically by adjusting laser wavelength, pulse duration, and optical path configuration based on the specific defect type and material being inspected. This allows the system to optimize sensitivity for different physical properties (acoustic impedance, density, elasticity) without requiring multiple specialized devices, thereby improving both reliability and detection precision.
Solution Approach 2:
The spectrum analysis module detects variations in reflected light spectrum characteristics caused by different defect physical properties. By analyzing spectral changes rather than just intensity changes, the device can identify and characterize multiple physical properties of subsurface defects simultaneously, enhancing both quality control reliability and measurement precision.
3Measurement precision
If multiple detection methods are combined for comprehensive defect analysis, then detection accuracy improves, but operation complexity increases
Solution Approach 1:
Multiple detection methods (optical reflection, spectrum analysis, acoustic signal detection) are merged into a single integrated detection head that simultaneously collects multiple types of signals. The unified data processing module automatically correlates and analyzes these signals together, providing comprehensive defect characterization without requiring the operator to manually coordinate multiple separate devices or procedures.
Solution Approach 2:
The device incorporates automatic defect characterization functionality that processes raw detection signals and generates comprehensive defect reports without requiring manual intervention or interpretation by the operator. The system automatically identifies defect types, dimensions, depth, and physical properties, making the complex multi-method detection system as easy to operate as a simple single-method device.
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 approach allows for accurate detection and identification of subsurface defects by providing spatial and spectral information, enhancing the ability to characterize defects and improve the quality control of ultra-precision optical components.
Implementation Method 1
the excitation laser generates a transient thermal expansion effect on a subsurface of the optical component
Implementation Method 2
the laser interference detection device is used for observing and recording ultrasonic vibration induced by the excitation laser
Implementation Method 3
the dispersion lens set focuses the white light, the excitation laser and the detection laser to different depths of the optical component
Data Source
AI summary
Disclosed are a device and method for detecting a subsurface defect of an optical component. According to the device and method, a spectral confocal technology, a laser scattering technology and a laser-induced ultrasonic technology are combined, excitation laser and detection laser are simultaneously focused to different depths of the optical component through a dispersion lens set, the excitation laser generates a transient thermal expansion effect on a subsurface of the optical component, the detection laser is used for observing and analyzing ultrasonic vibration of the subsurface defect under an action of the thermal expansion effect, and spatial distribution information and scattered spectral information of scattered light at a position of the subsurface defect are acquired by the spectral confocal technology. The device and method are suitable for nondestructive testing of a finished product of an ultra-precise optical component with a strict requirement on the subsurface defect.