Diffractive Multifocal IOL Relief Pattern for Pupil-Tolerant Vision
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Solution Overview
Problem
Existing multifocal intraocular lenses (IOLs) suffer from issues with image quality and pupil size variations, as they often rely on a single-valued diffractive optical power for near and intermediate vision, leading to defocused light on the retina and inadequate light distribution.
Innovation Solution
A multifocal implantable lens device with a diffractive surface featuring a sequence of annular concentric steps with varying primary and secondary widths, slopes, and alternating heights, allowing for two distinct sets of diffraction foci and a refractive focal point, optimized for near, intermediate, and far vision, using a combination of diffraction profiles to balance light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-valued diffractive optical power is used for near and intermediate vision, then the lens structure is simpler, but image quality deteriorates due to defocused light on the retina
Solution Approach 1:
The lens divides the aperture into multiple annular zones with different diffractive powers. Each zone is optimized for specific vision distances (near, intermediate, far), allowing light to be focused at multiple distinct points on the retina rather than a single focal point, thereby improving image quality across different viewing distances
Solution Approach 2:
Different regions of the lens are assigned different optical properties. The annular zones have varying step heights and diffractive powers tailored to their specific functional requirements, with inner zones optimized for near vision and outer zones for intermediate and far vision, creating local optimization of optical quality
2Device complexity
If conventional diffractive lenses are used, then the lens design is simpler, but performance deteriorates under pupil size variations
Solution Approach 1:
The lens design provides multiple diffractive orders that function across a range of pupil sizes. The multi-zone structure ensures that regardless of pupil diameter, appropriate annular zones remain active to provide the necessary diffractive power, making the lens universally effective across varying lighting conditions and pupil states
Solution Approach 2:
The lens performance dynamically adapts to pupil size changes through its multi-zone architecture. As the pupil constricts or dilates, different combinations of annular zones become active or inactive, automatically adjusting the effective diffractive power distribution to maintain optimal performance across dynamic pupil conditions
3Manufacturing precision
If multiple diffractive powers are used to improve vision quality, then light distribution improves, but the lens structure becomes more complex
Solution Approach 1:
The lens combines multiple diffractive profiles into a single integrated optical element. By superimposing different diffractive zone patterns on the same lens surface, the design achieves complex light distribution characteristics (multiple focal points with controlled intensity ratios) without requiring multiple separate lens components
Solution Approach 2:
The invention transitions from single-parameter optimization to multi-parameter control by varying not only the radial position of zones but also their step heights, widths, and diffractive orders independently. This adds dimensional complexity to the zone structure, enabling precise control over light distribution and focal point characteristics
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 lens provides improved vision quality by distributing light intensity effectively across multiple focal points, reducing defocused light and enhancing visual acuity for near, intermediate, and far vision, while maintaining tolerance to pupil size variations.
Implementation Method 1
A pair of diffraction orders is used to provide two lens powers simultaneously by using rigid implant. One power is used for distance vision and the other power is used for near vision.
Implementation Method 2
Generally, such lenses operate accordion to one two basic optical principles: refraction and diffraction.
Data Source
AI summary
An implantable lens device has a diffractive surface defining an optical axis. The diffractive surface comprises a relief pattern extending concentrically on the surface and having a sequence of annular concentric steps characterized by alternating heights, wherein an innermost step of the relief pattern has a largest height among all other steps.