Composite Diffractive Multifocal Intraocular Lens With Smooth Phase Changes
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Solution Overview
Problem
The complexity of manufacturing multifocal diffractive lenses increases with the number of focal points, leading to issues like light scattering and visual disturbances such as blur and halo due to the challenging surface-relief shape requirements.
Innovation Solution
A combined diffractive multifocal intraocular lens design featuring a first sawtooth-shaped structure with increasing phase change and a second sawtooth-shaped structure with decreasing phase change, alternately combined to form a phase profile that gradually changes in the radial direction, reducing abrupt phase value transitions at boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of focal points in multifocal diffractive lenses increases, then the vision correction capability is improved, but the manufacturing complexity increases and leads to incomplete manufacturing
Solution Approach 1:
The lens surface is divided into multiple radial regions, with each region containing a diffractive lens structure with a specific sawtooth shape. This segmentation allows different focal points to be created in different regions, achieving multifocal vision correction while maintaining manageable manufacturing complexity for each individual region.
Solution Approach 2:
Each radial region is assigned a specific diffractive lens structure with a sawtooth shape tailored to create the desired focal point. This local customization of optical properties enables precise control over light distribution to multiple focal points without requiring the entire lens surface to have uniform complex structures.
2Adaptability or versatility
If the surface-relief shape complexity increases to achieve multiple focal points, then the multifocal vision capability is improved, but light scattering increases causing visual disturbances
Solution Approach 1:
By segmenting the lens into radial regions with distinct diffractive structures, each region can be optimized to minimize light scattering while contributing to a specific focal point. This segmentation prevents the cumulative scattering effects that would occur with a single complex surface-relief structure.
Solution Approach 2:
Instead of using a single complex surface-relief structure that causes scattering, the invention inverts the approach by using multiple simpler sawtooth-shaped diffractive structures in different radial regions. This inverted strategy achieves the same multifocal capability with reduced scattering by distributing the optical function across multiple simpler elements.
3Manufacturing precision
If the surface-relief shape is precisely processed to achieve multiple focal points, then the optical performance is improved, but the manufacturing difficulty increases
Solution Approach 1:
The manufacturing process is simplified by dividing the lens into radial regions that can be processed independently with standard techniques. Each region's sawtooth-shaped diffractive structure can be manufactured with conventional precision, avoiding the need for extremely complex single-step processing while maintaining overall optical performance.
Solution Approach 2:
The invention changes the manufacturing parameters from requiring a single complex surface-relief profile to creating multiple simpler sawtooth structures with controlled phase changes. This parameter change allows the use of existing manufacturing capabilities to achieve the desired optical function without pushing the limits of current precision manufacturing.
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
This design simplifies manufacturing, reduces light scattering, and minimizes visual disturbances while maintaining multiple focal points, achieving clear vision with reduced manufacturing complexity.
Implementation Method 1
diffractive lenses with multifocal or multiple focal points are widely used in optical lenses, especially intraocular lenses (IOLs) for ophthalmic purposes
Implementation Method 2
a first diffractive lens structure with a sawtooth shape, configured to increase a phase change value, a second diffractive lens structure with a sawtooth shape, configured to decrease a phase change value
Data Source
AI summary
The present invention relates to a composite diffractive intraocular lens having at least one optical magnification or focal length. The composite diffractive intraocular lens comprises and combines a first diffractive lens structure having a saw-tooth shape and an increasing phase change values in a plurality of regions divided in the radial direction from the center of the lens, and a second diffractive lens structure having a saw-tooth shape and a decreasing phase change values in the same regions as the plurality of regions, and has a composite phase profile structure in which phase values at the boundaries of the regions do not sharply increase or decrease vertically.