Patterned Polarization Converter for Spatially Varying Light
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Solution Overview
Problem
Conventional polarizers are inadequate for applications requiring spatially non-uniform polarizers with varying linear or circular polarization directions, as they are either cost-prohibitive, complex, or unsuitable for practical manufacturing due to issues like insufficient extinction ratios and thickness problems.
Innovation Solution
A patterned polarization converter comprising a quarter wave plate and a patterned quarter wave plate with multiple retardation and non-retardation domains, fabricated using a multi-step photoalignment process, which can convert linearly polarized light to light with spatially varying polarization states, including radial and azimuthal polarization, and can be used in polarization sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire grid polarizers are used for patterned polarizers, then polarization performance is improved, but manufacturing cost increases due to photolithography requirements
Solution Approach 1:
The invention changes the manufacturing parameters from photolithography-based wire grid fabrication to a simpler process using stretched polymer films with embedded dichroic particles. This parameter change maintains polarization performance while dramatically reducing manufacturing cost and complexity for multi-domain patterns.
Solution Approach 2:
The invention replaces expensive, complex wire grid structures with a cheaper alternative using stretched polymer films containing dichroic particles. This substitution achieves comparable polarization performance at significantly lower cost, making the solution economically viable for practical applications.
2Ease of manufacture
If photoaligned azo-dye polarizers are used, then manufacturing complexity is reduced, but extinction ratio deteriorates due to insufficient performance
Solution Approach 1:
The invention creates a composite material system by embedding dichroic particles within a stretched polymer film matrix. This composite structure combines the manufacturing simplicity of photoalignment with the superior extinction ratio performance of dichroic materials, resolving the contradiction between ease of manufacture and polarization performance.
3Adaptability or versatility
If liquid crystal micro polarizer arrays are used, then spatially varying polarization is achieved, but device thickness increases causing image sensing problems
Solution Approach 1:
The invention uses a thin stretched polymer film structure to achieve spatially varying polarization directions. This thin-film approach maintains the adaptability for multi-domain patterns while keeping the overall device thickness minimal, solving the image sensing application problems caused by thick liquid crystal arrays.
4Ease of manufacture
If conventional patterned polarizers are used, then manufacturing simplicity is improved, but device complexity increases due to multiple components
Solution Approach 1:
The invention merges the polarizing function and the spatial patterning function into a single integrated stretched polymer film structure. By combining these functions, the device achieves complex multi-domain polarization patterns without requiring multiple separate components, thereby reducing overall device complexity while maintaining manufacturing simplicity.
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
The solution provides a cost-efficient method for fabricating patterned polarizers that can convert linearly polarized light to spatially varying polarization states, suitable for applications like polarization sensors and optical tweezers, with the ability to detect polarization states and optimize performance across different wavelengths.
Implementation Method 1
application of a photoalignment layer to a substrate and exposure of the photoalignment layer through a template patterned polarization converter
Implementation Method 2
depositing of a layer of LCP onto the photoalignment layer and polymerizing the layer of LCP
Implementation Method 3
the patterned quarter wave plate comprises at least one retardation domain corresponding to an optical axis and at least one other retardation domain corresponding to a different optical axis
Data Source
AI summary
The present invention provides a patterned polarization converter having multiple domains that can be used to convert input linear polarized light to output light with spatially varying polarization states, including domains that produce linearly polarized light and domains that produce circular polarized light based on the patterning of the domains. A patterned polarization converter having multiple domains may be used in a polarization sensor application capable of detecting the polarization state of input light. The present invention further provides patterned radial and azimuthal polarization converters, which have utility in applications such as optical tweezers. Additionally, patterned polarization converters may be used to fabricate more patterned polarization converters having the same pattern using one-step photoalignment to copy the pattern of an existing patterned polarization converter to an unpatterned photoalignment layer.