Diffractive Waveplate Lens Fabrication via Replication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for fabricating diffractive waveplate lenses and mirrors are limited in size, focal length, and grating spacing, and often result in imperfections that prevent their use in applications requiring close tolerances.
Innovation Solution
The methods involve using a replication technique with a photoaligned alignment layer, where a collimated laser beam is propagated through a master diffractive waveplate lens to create a replica with half the focal length and twice the grating spacing, and stacking multiple lenses to achieve shorter focal lengths and larger sizes, along with the use of birefringent media and interferometric methods for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If prior art fabrication techniques are used, then manufacturing simplicity is maintained, but manufacturing precision deteriorates due to imperfections in fabricated parts
Solution Approach 1:
The fabrication process is segmented into distinct stages: master lens fabrication, alignment layer deposition, photolithographic patterning, and replica fabrication. Each stage is optimized independently to achieve cumulative precision that exceeds what single-step prior art methods could deliver.
Solution Approach 2:
The invention uses a master diffractive waveplate lens as a template to create replica lenses. The master lens serves as a precise master pattern that is copied onto replicas through photolithographic processes, ensuring that replica parts achieve the same high precision as the master without requiring each to be fabricated independently from scratch.
2Length of moving object
If prior art techniques are used, then device simplicity is maintained, but focal length cannot be sufficiently shortened
Solution Approach 1:
The invention transitions from conventional single-element lens design to multi-element stacked lens systems. By stacking multiple diffractive waveplate lenses with different focal lengths and orientations, the system achieves ultra-short effective focal lengths that cannot be obtained with single elements, while each individual element maintains manufacturable grating spacing precision.
Solution Approach 2:
The patent employs composite optical systems combining multiple diffractive waveplate lenses made from birefringent materials with different optical properties. These composite lens stacks enable focal length control through material selection and stacking configuration, achieving short focal lengths without compromising the manufacturing precision of individual grating structures.
3Manufacturing precision
If prior art methods are used, then ease of manufacture is maintained, but grating lines cannot be sufficiently closely spaced
Solution Approach 1:
The invention replaces mechanical direct-write or e-beam lithography methods with photolithographic techniques using UV or visible light. This substitution enables mass production of closely spaced grating lines through optical projection methods, achieving finer grating spacing that is easier to manufacture at scale compared to mechanical or electron-beam approaches.
Solution Approach 2:
The patent utilizes changes in photolithographic parameters including wavelength of exposure light, numerical aperture of projection optics, and photoresist material properties to achieve different grating spacing resolutions. By optimizing these parameters, the process can produce closely spaced grating lines that would be difficult to achieve with fixed mechanical fabrication methods.
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 the fabrication of diffractive waveplate lenses and mirrors with larger sizes, shorter focal lengths, and more precise grating patterns, overcoming the limitations of prior art and enabling their use in applications such as imaging systems, astronomy, and photonics.
Implementation Method 1
diffractive waveplate lens in close proximity to the alignment layer of the replicated diffractive waveplate lens
Implementation Method 2
an initially collimated laser beam is propagated through a birefringent medium such as a nematic liquid crystal
Implementation Method 3
with the birefringent medium confined in a nearly planar region in which one boundary of the confined region is bounded on one side by a solid transparent material having the shape of a Fresnel lens
Implementation Method 4
interferometric methods for precise alignment
Data Source
AI summary
Methods of fabricating optical lenses and mirrors, systems and composite structures based on diffractive waveplates, and fields of application of said lenses and mirrors that include imaging systems, astronomy, displays, polarizers, optical communication and other areas of laser and photonics technology. Diffractive lenses and mirrors of shorter focal length and larger size, with more closely spaced grating lines, and with more exacting tolerances on the optical characteristics, can be fabricated than could be fabricated by previous methods.