Alternating Diffractive Subzones for Intraocular Lens Scattering

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Solution Overview

Problem

Conventional diffractive-refractive intraocular lenses suffer from light scattering and dispersion due to vertical steps between diffractive zones, leading to reduced image contrast sensitivity and inefficiency.

Innovation Solution

A lens device with alternating positive and negative diffractive subzones arranged without vertical steps, featuring constant-sign curvature along the radial direction, which reduces light scattering and enhances diffraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional diffractive-refractive intraocular lenses use vertical steps between diffractive zones, then the lens structure is simple to manufacture, but light scattering and dispersion occur leading to reduced image contrast sensitivity

Engineering Contradiction:

Improvelight scattering lossVSAvoidlens structure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the vertical steps between diffractive zones that cause light scattering. By removing these harmful geometric features while retaining the diffractive zone structure, the lens reduces light scattering loss without completely redesigning the entire optical system.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using conventional vertical step profiles between diffractive zones, the patent inverts the approach by using continuous curved surfaces. This inversion of the geometric profile eliminates the scattering interfaces while maintaining the diffractive functionality through alternating positive and negative curvature zones.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If conventional diffractive-refractive intraocular lenses use vertical steps between diffractive zones, then the manufacturing process is simplified, but image contrast sensitivity is reduced due to light dispersion

Engineering Contradiction:

Improveimage contrast sensitivityVSAvoidlens fabrication ease

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies curvature to the diffractive zone interfaces, replacing vertical steps with continuous curved surfaces. This spheroidality principle smooths the transitions between zones, eliminating light scattering at sharp edges while maintaining manufacturability through standard curvilinear lens fabrication techniques.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Productivity

If alternating positive and negative diffractive subzones are used, then diffraction efficiency is enhanced and light distribution is improved, but the lens design complexity increases

Engineering Contradiction:

Improvediffraction efficiencyVSAvoiddiffractive zone configuration complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating alternating positive and negative curvature regions within the diffractive zones. Each local region has a specific curvature sign optimized for its function, with positive curvatures focusing light and negative curvatures dispersing it, thereby enhancing overall diffraction efficiency through localized optical properties.

Inventive Principle:

Principle #3Local quality

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 solution improves light distribution and image contrast sensitivity by minimizing light loss and dispersion, providing a more efficient multifocal capability with enhanced vision correction for near, intermediate, and far vision.

Implementation Method 1

Each of the diffractive zone may be demarcated by steps wherein base of each step may start from the base lens. For light incident at an angle 'θ ', fraction of light scattered at the step of lens is given by... The lens device comprises a base lens formed with a plurality of diffractive zones, each having a negative diffractive subzone and a positive diffractive subzone

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

The base lens is also formed with a plurality of refractive zones... the refractive zones are offset from the base lens to compensate a phase difference induced by light diffracted from the diffractive zones and refracted from the refractive zones

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS20230098580A1Lens providing both positive and negative diffraction

Publication Date: 2023.03.30 ROOP PRAKHYAT

AI summary

A lens device comprises a base lens formed with a plurality of diffractive zones, each having a negative diffractive subzone and a positive diffractive subzone. The negative and the positive diffractive subzones are optionally and preferably arranged alternately. Each diffractive subzone typically has a constant-sign curvature along a radial direction of the base lens.