Polarized Light Substrate Hole Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical systems that rely on polarized light for detecting through holes in substrates struggle with substrates having rough surfaces or thin, translucent materials, as light passing through holes can be confused with surface features, making it difficult to discern hole existence, location, and perimeter.
Innovation Solution
The use of a first polarization filter directing polarized light towards a substrate, where unscattered light passing through holes is blocked by a second polarization filter with an angularly offset axis, allowing scattered light to be detected by a sensor, thereby identifying holes based on the absence of unscattered light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical systems detect light passing through holes in substrates, then hole detection is enabled, but holes are confused with surface features making it difficult to discern hole existence, location, and perimeter
Solution Approach 1:
The patent changes the polarization parameter of light to distinguish between light passing through holes and light interacting with surface features. By using polarized light and detecting polarization state changes, the system can accurately identify holes even on rough surfaces where conventional optical systems fail.
Solution Approach 2:
The patent introduces a polarization filter as an intermediary element between the light source and the substrate. This filter selectively transmits polarized light, creating a controlled illumination that interacts differently with holes versus surface features, enabling clear distinction between the two.
2Adaptability or versatility
If conventional optical systems are used on rough surfaces, then detection is attempted, but the systems do not work well with substrates having relatively rough surfaces
Solution Approach 1:
The patent changes the polarization parameter of the incident light to make the detection system adaptable to rough surfaces. Polarized light maintains its orientation through the substrate, allowing the system to distinguish holes from surface irregularities regardless of surface roughness.
3Measurement precision
If systems illuminate substrate surfaces to detect light passing through holes, then hole detection is enabled, but light from holes is confused with surface features scattering or absorbing light
Solution Approach 1:
The patent changes the polarization state parameter of light to create a detection signature that is unique to holes. Polarized light passing through holes maintains its polarization state, while light interacting with surface features becomes depolarized or scattered, providing clear information differentiation.
Solution Approach 2:
The patent introduces a second polarization filter as an intermediary detection element. This filter is oriented to block depolarized light from surface features while allowing polarized light from holes to pass through, eliminating the confusion between holes and surface features.
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 effectively detects through holes in substrates with improved accuracy, even on rough or translucent materials, by distinguishing unscattered light from scattered light, enhancing the ability to monitor and control manufacturing processes in high-speed production environments.
Implementation Method 1
a light source directs light through a first polarization filter having a first polarization axis, wherein polarized light travels from the first polarization filter and toward a first surface of a substrate
Implementation Method 2
the orientation of the polarized light traveling through substrate material changes, and thus is scattered
Implementation Method 3
The second polarization filter includes a second polarization axis that is angularly offset from and not parallel with the first polarization axis. Thus, the second polarization filter blocks the advancement of some or all the unscattered light while the scattered light travels through the second polarization filter
Data Source
AI summary
The methods herein utilize polarized light for detecting through holes in substrates. A light source directs light through a first polarization filter having a first polarization axis, wherein polarized light travels from the first polarization filter and toward a substrate. The orientation of the polarized light is changed while traveling through substrate material, and is scattered. However, polarized light traveling through a hole in the substrate remains unscattered. A second polarization filter receives unscattered light and scattered light traveling away from the substrate. The second polarization filter includes a second polarization axis angularly offset from and not parallel with the first polarization axis. As such, the second polarization filter blocks the advancement of unscattered light while the scattered light is not blocked by the second polarization filter. The hole is detected based on an absence of unscattered light surrounded by light traveling from the second polarization filter.