Multifocal Lens Design Eliminating Chromatic Aberration
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Solution Overview
Problem
Conventional multifocal lenses with refractive and diffractive powers suffer from longitudinal chromatic aberrations, particularly in the smallest principal powers, which affect vision quality, especially in ophthalmic applications, and are hindered by the presence of topographic or optical steps that complicate precision and comfort.
Innovation Solution
A multifocal lens design featuring multiple principal powers, where at least one is refractive and one is diffractive, with lens portions having annular zones and sub-zones that share the same averaged refractive power, eliminating diffractive longitudinal chromatic aberration in the smallest power by optimizing the configuration of main and phase sub-zones and their relative intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional diffractive lenses are used with topographic steps between zones, then diffractive powers can be achieved, but manufacturing precision deteriorates and wearing comfort is reduced
Solution Approach 1:
The patent removes the topographic steps from the lens surface, extracting the harmful element that caused manufacturing difficulties and comfort problems, while retaining the diffractive power through alternative zone design
Solution Approach 2:
The patent replaces the mechanical topographic steps with an optical solution using annular zones with different refractive indices, substituting a mechanical structure with an optical property-based approach
2Power
If conventional diffractive lenses are used with optical steps between zones, then diffractive powers can be achieved, but wearing comfort deteriorates
Solution Approach 1:
The patent removes the optical steps from the lens surface, extracting the harmful element that caused discomfort during wearing, while retaining the diffractive power through alternative zone design
Solution Approach 2:
The patent creates a homogeneous lens surface without steps or discontinuities, ensuring uniform optical properties across the lens that improve wearing comfort while maintaining functional performance
3Adaptability or versatility
If conventional multifocal lenses are used, then multiple principal powers can be achieved, but longitudinal chromatic aberration increases
Solution Approach 1:
The patent applies different refractive indices to different annular zones of the lens, creating local optical properties that compensate for chromatic aberration while maintaining multiple principal powers
Solution Approach 2:
The patent uses composite optical zones with different refractive indices within the same lens, combining materials or regions that have complementary optical properties to cancel chromatic aberration
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 enhances vision clarity across near, intermediate, and far ranges without longitudinal chromatic aberration, improving imaging characteristics and comfort by eliminating topographic steps and maintaining continuous optical surfaces.
Implementation Method 1
at least one principal power is refractive
Implementation Method 2
at least one further principal power is diffractive
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a multifocal lens (13, 18, 24) with a number n > 2 of principal powers, wherein at least one principal power is refractive and at least one principal power is diffractive, including a first lens portion (15, 16, 23, 25, 26) having at least one first annular zone (6, 10, 10, 27, 28) and at least a second lens portion (15, 16, 23, 25, 26) having at least one second annular zone (6, 10, 10, 27, 28), wherein the zones (6, 10, 10, 27, 28) each have at least one main sub-zone (7, 11, 20, 29, 31) and at least one phase sub-zone (8, 12, 21, 30, 32), wherein for forming the n principal powers, a maximum of n - 1 lens portions (15, 16, 23, 25, 26) are combined, and an averaged refractive power of a zone (6, 10, 10, 27, 28) of the first lens portion (15, 16, 23, 25, 26) is equal to an averaged refractive power of a zone (6, 10, 10, 27, 28) of the second lens portion (15, 16, 23, 25, 26).