Prism-Enhanced Diffractive Lenses for Chromatic Aberration
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Solution Overview
Problem
Conventional diffractive lenses suffer from reduced diffraction efficiency due to their intrinsic wavelength dependence, as they can only be optimized for a single wavelength, leading to performance degradation across the visible spectrum.
Innovation Solution
Incorporating additional prismatic structures at the phase wrap regions of diffractive lenses to mitigate destructive interference, enhancing diffraction efficiency across a broader range of wavelengths, particularly beneficial for ophthalmic lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional diffractive lens is optimized for a single design wavelength, then diffraction efficiency is maximized at that wavelength, but diffraction efficiency decreases at other wavelengths
Solution Approach 1:
The patent combines diffractive optics with prismatic structures to create a hybrid optical element. The diffractive phase wraps provide wavelength-selective focusing, while the prismatic structures redirect light to compensate for chromatic dispersion, merging two optical mechanisms to achieve both high efficiency at design wavelength and improved performance across broader wavelength ranges
Solution Approach 2:
The prismatic structures are strategically placed at specific locations corresponding to phase wrap regions rather than uniformly across the entire lens. This localized modification allows the lens to maintain optimal diffractive performance at the design wavelength while providing chromatic compensation only where needed to improve overall wavelength adaptability
2Loss of energy
If phase reset is set to integer number of wavelengths for perfect constructive interference, then diffraction efficiency reaches 100% at design wavelength, but performance degrades when wavelength deviates from design wavelength
Solution Approach 1:
The prismatic structures act as intermediary elements that modify light paths between the diffractive phase wraps and the focal point. By introducing these intermediate refractive elements, the system can maintain constructive interference conditions more robustly across varying wavelengths, mediating between the wavelength-specific diffractive effect and the need for consistent performance
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 prism-enhanced lenses demonstrate improved average diffraction efficiency and reduced wavelength sensitivity, maintaining high Strehl ratios over the visible spectrum, making them suitable for vision correction applications.
Implementation Method 1
the optical power induced via constructive interference at the focal point via diffraction
Implementation Method 2
constructive interference at the focal point
Implementation Method 3
additional prismatic structures at the phase wrap regions to mitigate unwanted destructive interference
Data Source
AI summary
An electro-active lens is presented which utilizes a surface relief structures and an electro-active material, with a change in refractive index facilitating the change in optical properties. A molded structure and a liquid crystal are used to form a diffractive lens. In addition to the classical approach of utilizing diffractive optics and multiple Fresnel zones to form a lens, an additional structure is placed between Fresnel zones in order to improve the diffraction efficiency across the visible spectrum and reduce chromatic aberration.