Birefringent Lens Group for Variable Position Inspection
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Solution Overview
Problem
Inspection devices face challenges in efficiently inspecting targets with variable positions due to the need for frequent lens tip changes, which decreases inspection efficiency and user convenience, as larger depth of field lenses result in darker images.
Innovation Solution
An optical system with a polarizer, light modulating element, and birefringent lens group that converts incident light into linearly polarized light and refracts or reflects it under different refractive indices to enable inspection of targets at various positions, allowing for switching between near and far field focal lengths without changing tips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a lens system with fixed focal length is designed to achieve large depth of field, then the inspection range is improved, but the image brightness deteriorates
Solution Approach 1:
The patent applies dynamics by making the focal length adjustable rather than fixed. The lens system can dynamically change its focal length based on the inspection requirements, allowing optimization between depth of field and image brightness for different inspection scenarios.
Solution Approach 2:
The patent changes the focal length parameter of the lens system to resolve the contradiction. By varying the focal length parameter, the system can achieve both large depth of field for broad inspection range and adequate image brightness when needed.
2Adaptability or versatility
If multiple lens tips with different DOF are used to inspect different fields, then the adaptability is improved, but the operation time increases
Solution Approach 1:
Instead of using multiple static lens tips, the patent implements a dynamic lens system that can change focal length during operation. This eliminates the need to physically change tips while maintaining adaptability to different inspection fields.
Solution Approach 2:
The patent creates a universal lens system that can perform multiple functions (inspecting different fields at different distances) through focal length adjustment, replacing the need for multiple specialized lens tips with a single multi-functional lens.
3Device complexity
If a single lens system is used for both near and far field inspection, then the device complexity is reduced, but the manufacturing precision requires higher focal length adjustment accuracy
Solution Approach 1:
The patent uses a dynamic focal length adjustment mechanism that can precisely change the focal length of the lens system. This dynamic control allows a single lens to achieve both near and far field inspection capabilities with high precision.
Solution Approach 2:
The patent replaces the mechanical approach of using multiple discrete lens tips with a controllable focal length adjustment mechanism, likely using optical elements whose focal length can be dynamically changed through non-mechanical means such as liquid crystals or deformable mirrors.
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
Enables efficient inspection of targets at varying positions by automatically adjusting focal lengths, improving image quality and convenience by maintaining clear images across different distances without the need for frequent lens changes.
Implementation Method 1
a polarizer configured to convert an incident light reflected or diffused from the target into linearly polarized light
Implementation Method 2
a lens group comprising at least one birefringent element, the birefringent element configured to refract or reflect the modulated linearly polarized light with a first polarization state under a first refraction index
Data Source
AI summary
An optical system configured to visually inspect a target having a variable position with respect to the optical system is provided. The optical system includes a polarizer configured to convert an incident light reflected or diffused from the target into linearly polarized light; a light modulating element configured to modulate a polarization state of the linearly polarized light in response to control signals; and a lens group comprising at least one birefringent element, the birefringent element configured to refract or reflect the modulated linearly polarized light with a first polarization state under a first refraction index to enable inspection of the target at a first object position, and the birefringent element further configured to refract or reflect the modulated linearly polarized light with a second polarization state under a second refraction index to enable inspection of the target at a second object position.