Diffractive Lens Layout for Transverse Multiple Focal Points
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Solution Overview
Problem
Conventional diffractive optical elements (DOEs) are limited in their ability to simultaneously form multiple focal points along a surface transverse to the optical axis, preventing simultaneous imaging without additional beam-splitting arrangements, especially when dealing with polychromatic or monochromatic light.
Innovation Solution
A diffractive lens with a spatial material pattern on an optical substrate, divided into contiguous areas, introduces distinct phase changes to different portions of the light wavefront, allowing multiple focal points to be formed at predetermined distances along the lens surface, regardless of light spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional Fresnel lenses are used to create multiple focal points, then the focal points are distributed along the optical axis, but this prevents simultaneous imaging in non-overlapping areas without additional beam-splitting arrangements
Solution Approach 1:
The patent transitions the focal point distribution from the optical axis (one-dimensional arrangement) to the transverse plane (two-dimensional arrangement). By distributing focal points across multiple dimensions in the transverse plane rather than along a single axis, the system enables simultaneous imaging in non-overlapping areas without requiring additional beam-splitting components, thus resolving the contradiction between ease of operation and device complexity
2Ease of operation
If multiple Fresnel lens elements are combined to achieve transverse focal point distribution, then simultaneous imaging is enabled, but the manufacturing complexity increases
Solution Approach 1:
The patent merges multiple Fresnel lens elements into a single monolithic optical component. The transverse focal point distribution is achieved by integrating multiple phase-modulating regions within one continuous substrate, eliminating the need to assemble separate lens elements. This merging approach maintains the simultaneous imaging capability while significantly simplifying manufacturing processes and reducing alignment requirements
3Device complexity
If conventional diffractive lenses are used, then the structure is simple, but the ability to create spatially separated focal points transverse to the optical axis is limited
Solution Approach 1:
The patent applies local quality by assigning different phase modulation characteristics to different regions within the lens aperture. Each local region is designed with specific phase profiles that collectively produce the desired transverse focal point distribution. This regional differentiation enables the lens to achieve versatile transverse focal point arrangement while maintaining an overall simple diffractive structure, resolving the contradiction between device complexity and adaptability
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 simultaneous imaging of multiple focal points without beam-splitting, enhancing imaging capabilities and allowing for higher resolution image reconstruction in a single snapshot, particularly in Fourier ptychography systems.
Implementation Method 1
A diffractive lens with multiple contiguous areas on an optical substrate, where each area introduces a specific phase change to the light wavefront
Implementation Method 2
a first area of the multiple contiguous areas is configured to introduce a first phase change in a first portion of a light wavefront incident onto the incident surface
Data Source
AI summary
A diffractive optical element configured as a lens having such an aperture function that causes light incident onto such lens to form a multiplicity of focal points (whether real or virtual) that do not lie along the same axis transverse to the surface of such lens, thereby simultaneously forming a multiplicity of spatially-independent optical images distributed transversely to a normal drawn to a surface of such lens. A method of using such diffractive optical element.