Multifocal Lens with Slanted Steps for Aberration Control
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Solution Overview
Problem
Conventional multifocal intraocular lenses face challenges in providing optimal vision correction by evenly distributing refractive and diffractive powers across the lens, often resulting in aberrations, halos, and reduced light transmission.
Innovation Solution
A multifocal lens design featuring a lens body with concentric annular zones separated by slanted steps, where the zones provide both diffraction and refraction, while the steps are devoid of optical power, ensuring uniform refractive power and high light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional multifocal intraocular lenses evenly distribute refractive and diffractive powers across the lens, then multiple focal points are achieved, but aberrations and halos increase
Solution Approach 1:
The lens is divided into distinct functional zones: a central refractive zone for distance vision and surrounding diffractive zones for near and intermediate vision. This segmentation allows each zone to perform its specific optical function without interfering with others, reducing aberrations and halos while maintaining multiple focal points
Solution Approach 2:
Different regions of the lens are assigned different optical properties: the central zone has refractive power optimized for distance vision, while the peripheral zones have diffractive structures optimized for near and intermediate vision. This local differentiation enables optimal vision correction at each focal distance without compromising overall image quality
2Adaptability or versatility
If conventional multifocal lenses use both refractive and diffractive zones, then vision range is extended, but light transmission is reduced
Solution Approach 1:
By segmenting the lens into refractive and diffractive zones with clearly defined boundaries, the design minimizes overlapping optical paths that would otherwise cause light loss. The slanted steps between zones are optimized to reduce light scattering while maintaining sharp focal separation
Solution Approach 2:
The diffractive zones are designed to capture only the necessary portion of incident light for near and intermediate vision, leaving the majority of light transmission intact for distance vision through the central refractive zone. This partial action approach ensures sufficient light reaches the retina for all focal distances without excessive light loss
3Adaptability or versatility
If diffractive zones are used to provide multiple focal powers, then near and distance vision are achieved, but the zeroth order power causes defocused light on the retina
Solution Approach 1:
The design extracts and isolates the zeroth order diffractive power by assigning it specifically to the central refractive zone, while the first and higher order diffractive powers are directed to the peripheral diffractive zones. This separation ensures that defocused light from the zeroth order is minimized and does not interfere with the focused images from other zones
Solution Approach 2:
The zeroth order diffractive power, which would normally cause defocused light and reduce image quality, is converted into a beneficial component by aligning it with the central refractive zone to enhance distance vision. The defocused light is redirected to non-critical areas of the retina where it does not interfere with the focused images from the diffractive zones
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 design enhances vision correction by reducing aberrations and halos, allowing for clear intermediate, near, and distance vision with high light transmission, suitable for intraocular and contact lenses.
Implementation Method 1
The concentric zones effect refraction of incident light
Implementation Method 2
The concentric zones effect diffraction of incident light
Data Source
AI summary
A multifocal lens device is disclosed. The device comprises a lens body being formed with a plurality of concentric annular zones separated by slanted steps. The concentric zones effect both diffraction and refraction of incident light, while the steps are substantially devoid of any diffractive or refractive power.