Gradient Index Lens with Flattened Side for Planar Sensor Integration
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Solution Overview
Problem
Conventional lenses suffer from geometrical aberrations, making it difficult to create ideal optical devices, especially for wide-angle imaging systems, and gradient index lenses with favorable imaging characteristics are challenging to fabricate and integrate with planar CCD arrays.
Innovation Solution
A class of gradient index lenses with no geometrical aberrations is developed by applying transformation optics to modify the shape of a Luneburg lens, using metamaterials and quasi-conformal transformation optics to create a lens with a flattened side and a locus of focal points on a planar surface, achieved through laminating material layers with varying refractive indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lenses are used, then the lens structure is simple and easy to manufacture, but geometrical aberrations such as spherical aberration cannot be eliminated
Solution Approach 1:
The patent applies gradient index technology to create lenses with spatially varying refractive indices. Different regions of the lens have different refractive index values, allowing local optimization of light path control to eliminate spherical aberration while maintaining a relatively simple spherical lens structure that is easier to manufacture than complex multi-element lens systems.
Solution Approach 2:
The patent changes the refractive index parameter from a constant value in conventional lenses to a spatially varying gradient distribution. This parameter change enables the lens to control light paths more precisely, eliminating geometrical aberrations while maintaining a simple single-element structure that is easier to manufacture than traditional aberration-correcting lens systems.
2Reliability
If gradient index lenses with curved focal surfaces are used, then geometrical aberrations are reduced, but the focal surface is incompatible with planar CCD arrays
Solution Approach 1:
The patent introduces asymmetry by flattening one surface of the spherical gradient index lens while maintaining the gradient index distribution. This asymmetric modification changes the focal surface from curved to planar, making it compatible with planar CCD arrays while preserving the aberration-reduction benefits of the gradient index structure.
Solution Approach 2:
The patent modifies the lens geometry by flattening one surface, effectively changing the dimensional characteristics of the lens interface. This transformation from a fully spherical geometry to a plano-convex or plano-concave geometry with gradient index allows the focal surface to be rendered planar, enabling compatibility with planar sensor arrays.
3Reliability
If large index gradients are achieved in gradient index lenses, then imaging performance is improved, but fabrication control becomes difficult
Solution Approach 1:
The patent divides the gradient index lens into multiple discrete layers, each with a uniform refractive index. By stacking these layers with gradually changing indices, the continuous gradient is approximated in a manufacturable way. This segmentation approach enables precise control of the index distribution through layer thickness and material selection, improving fabrication control while maintaining imaging performance.
Solution Approach 2:
The patent uses composite material structures, combining multiple materials with different refractive indices in a layered configuration. This composite approach allows precise control of the effective refractive index distribution through material selection and layer design, enabling large index gradients to be achieved with controlled fabrication processes.
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 enables lenses with improved imaging capabilities, including wide field-of-view and reduced distortion, suitable for applications like automotive radar and communication satellites, without requiring advanced materials beyond current technology, and maintains performance across various frequencies.
Implementation Method 1
the index of refraction is varied throughout the body of the lens. Rays are no longer abandoned once entering the medium, but instead can be guided with far greater control to their ultimate destination.
Data Source
AI summary
Gradient index lenses with no aberrations and related methods for making such lenses are described. In one aspect, a gradient index lens can be a substantially spherically-shaped lens that has at least one side that is flattened such that a locus of focal points resides on a plane. A method for making a gradient index lens can include forming material layers, each of the material layers defining an effective refractive index, and laminating the material layers together to form a substantially spherically-shaped lens having at least one side that is flattened to a substantially planar surface. The material layers can have a gradient refractive index distribution such that a locus of focal points resides on the substantially planar surface.