Differential Interference Optical Film Defect Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting optical film defects are limited to surface defects on single-sided films and fail to effectively detect internal defects like bubbles and impurities, and are susceptible to the reflective properties of the film surface, leading to false detection and missed inspections.
Innovation Solution
A method using differential interference, where a planar light wave passes through an optical film, forming parallel beams that create a differential interference image, allowing for the detection of both superficial and internal defects by analyzing phase changes, independent of surface reflective properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If machine vision method is used to detect surface defects, then detection of surface defects is achieved, but internal defects such as bubbles and impurities cannot be detected
Solution Approach 1:
The patent introduces light as an intermediary to penetrate the optical film and reveal internal defects. By using light transmission and interference patterns, the method enables detection of both surface and internal defects without direct contact, solving the limitation of machine vision which can only detect surface defects.
Solution Approach 2:
The patent replaces the mechanical/optical imaging system (machine vision) with a light interference-based detection system. This substitution allows the detection method to penetrate the optical film and detect internal defects through light transmission and interference patterns, achieving comprehensive defect detection.
2Measurement precision
If machine vision method is used, then surface defect detection is possible, but detection results are susceptible to surface reflective properties causing false detection and missed inspection
Solution Approach 1:
The patent uses light transmission through the optical film as an intermediary mechanism, allowing detection of defects without being affected by surface reflectivity. The light passes through the film and interacts with defects internally, creating interference patterns that reveal defect locations and characteristics independent of surface reflective properties.
Solution Approach 2:
The patent changes the detection parameter from reflected light (susceptible to surface reflectivity) to transmitted light interference patterns. By measuring phase changes and interference fringes caused by light transmission through the film, the method achieves defect detection that is independent of surface reflective properties.
3Adaptability or versatility
If differential interference method is used, then both surface and internal defects can be detected with clear stereoscopic images, but the detection system becomes more complex
Solution Approach 1:
The patent segments the optical detection system into distinct functional modules: light source, optical path components (beam splitter, mirrors, lenses), interference chamber, and detection system. This segmentation allows each component to perform its specific function while maintaining overall system manageability and reducing complexity through modular design.
Solution Approach 2:
The patent employs universal optical components such as beam splitters, mirrors, and lenses that serve multiple functions within the differential interference system. These components facilitate light division, path manipulation, and interference pattern generation simultaneously, reducing the need for specialized components and simplifying the overall system architecture.
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 provides clear, stereoscopic images of defects, enabling reliable detection of bubbles and irregularities on both surfaces and inside the film, with high resolution and low cost, suitable for factory production lines.
Implementation Method 1
the planar light wave sequentially passes through a diaphragm, the optical film, a first collimating lens and a lenticular lens, and then form two parallel outgoing beams by differential interference
Implementation Method 2
two parallel outgoing beams pass through a second collimating lens to form a differential interference image on a photodetector
Data Source
AI summary
A method for detecting optical film defects based on differential interference, comprising: an incident light is adjusted into a planar light wave, and the surface of an optical film to be detected is adjusted to be perpendicular to the planar light wave; the planar light wave sequentially passes through a diaphragm, the optical film, a first collimating lens and a lenticular lens, and then form two parallel outgoing beams by differential interference; the two parallel outgoing beams pass through a second collimating lens to form a differential interference image on a photodetector; and the differential interference image is analyzed to detect both superficial and internal defects of the optical film.