Trifocal Ophthalmic Lens Diffractive Profile Phase Shift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current multifocal artificial ophthalmic lenses face limitations in providing clear vision at intermediate distances due to dependence on pupil size and light intensity distribution, leading to suboptimal performance and increased light loss and scatter, especially with the creation of higher diffraction orders.
Innovation Solution
A trifocal artificial ophthalmic lens design that enhances diffractive secondary peaks between the 0th and 1st diffraction orders, achieving three focal points without creating additional diffraction orders, with a maximum phase shift of the central zone greater than λ/2 but less than 3/4λ, ensuring sharp images at distant, near, and intermediate distances through constructive interference of side maxima.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffractive multifocal artificial ophthalmic lenses create multiple diffraction orders to provide multiple focal points, then near and distant vision are improved, but light loss and scatter increase significantly
Solution Approach 1:
The patent changes the diffraction grating parameters by using a blazed grating profile with asymmetric zone widths and optimized phase shifts. This redirects most diffracted light into the first diffraction order while creating a controlled secondary peak between orders, achieving trifocality with minimal light loss compared to conventional symmetric diffractive lenses
Solution Approach 2:
The patent applies different optical properties to different zones of the lens. The central zone has a specific phase shift range (0.25-0.5 wavelengths) optimized for intermediate focus, while outer zones follow the blazed grating pattern for near and distant focuses. This local differentiation optimizes light distribution across three focal points
2Ease of manufacture
If conventional diffractive lenses use maximum phase shift of λ/2 to create bifocal points, then manufacturing is simplified, but intermediate distance vision remains poor due to weak secondary peaks
Solution Approach 1:
The patent modifies the phase shift parameter from the conventional λ/2 maximum to a range of 0.25-0.5 wavelengths, with the central zone specifically optimized within this range. This parameter change enhances the secondary diffraction peak intensity, providing clear intermediate distance vision while remaining manufacturable
Solution Approach 2:
The patent introduces dynamic adaptability through the phase shift range rather than a fixed value. The central zone's phase shift can be optimized based on specific application requirements within the 0.25-0.5 wavelength range, allowing flexibility in designing for different pupil sizes and viewing conditions
3Reliability
If multifocal lenses use concentric zones with differing refractive power to provide multiple focuses, then near and far vision are achieved, but optical performance strongly depends on pupil size
Solution Approach 1:
The patent combines refractive and diffractive optical elements in a hybrid lens design. The refractive component provides the base optical power, while the diffractive blazed grating overlay creates the multifocal effect. This composite approach reduces pupil size dependence compared to purely refractive or purely diffractive designs
Solution Approach 2:
The patent segments the lens into functional zones: a central zone with optimized phase shift for intermediate focus and outer zones following the blazed grating pattern for near and distant focuses. This segmentation allows each zone to contribute optimally to specific distance ranges, improving overall adaptability
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 provides improved optical performance and extended depth of focus, especially at intermediate distances, with enhanced image quality and reduced light loss, even at small pupil diameters, effectively addressing the limitations of previous solutions.
Implementation Method 1
at least one of the anterior side optical surface and the posterior side optical surface contains an optics having three useful focal points and having at least a partially diffractive profile
Implementation Method 2
achieving three focal points without creating additional diffraction orders, with a maximum phase shift of the central zone greater than λ/2 but less than 3/4λ, ensuring sharp images at distant, near, and intermediate distances through constructive interference of side maxima
Data Source
AI summary
The invention relates to a trifocal artificial ophthalmic lens (20), which contains an anterior side optical surface (21), a posterior side optical surface (22) and an optical axis (23), at least one of the anterior side optical surface (21) and the posterior side optical surface (22) contains an optics having three useful focal points and having an at least partially diffractive profile. The three useful focal points correspond to focal points (31, 32) belonging to the 0th and 1st diffraction orders of the diffractive profile, and to a focal point (33) belonging to an enhanced diffractive secondary peaks between the 0th and the 1st diffraction orders. The invention also relates to a method of producing the aforementioned trifocal artificial ophthalmic lens.