Multi-Focal Lens With Interlaced Zones for Extended Depth of Focus
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Solution Overview
Problem
Existing imaging lenses lack an effective method to extend the depth of focus, particularly in applications requiring imaging of objects from multiple distances, such as medical and ophthalmic lenses.
Innovation Solution
A multi-focal lens design with interlaced lens zones of different optical functions, arranged in a non-diffractive pattern, where adjacent zones are spaced apart by a distance greater than the coherence length to prevent interference and diffraction, allowing light components to add in intensity rather than phase, thereby enhancing imaging clarity across various distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi-focal lenses with concentric annular rings of different optical powers are used, then extended depth of focus is achieved, but interference and diffraction patterns are created that reduce imaging clarity
Solution Approach 1:
The lens aperture is segmented into multiple zones with different optical powers (first, second, and third optical powers). These zones are arranged in an interlaced pattern rather than concentric rings, with each zone contributing to different focal planes. This segmentation allows the light to be divided into multiple beams that focus at different distances, extending the depth of focus while the specific geometric arrangement minimizes interference effects between the zones.
Solution Approach 2:
The patent employs an interlaced asymmetric arrangement of zones with different optical powers, breaking the conventional symmetric concentric ring pattern. The zones are positioned at specific angular intervals (e.g., 0°, 45°, 90°, 135°) creating an asymmetric distribution that prevents the formation of regular diffraction patterns while maintaining balanced optical performance across different focal planes.
2Adaptability or versatility
If conventional multi-focal lens designs are used, then imaging at multiple distances is enabled, but the structural complexity increases with multiple concentric regions
Solution Approach 1:
The lens design integrates multiple optical functions within a unified zone structure. Each zone can contribute to different focal planes (near, intermediate, and far vision), and the interlaced arrangement allows all zones to work simultaneously across the entire aperture. This multi-functional design eliminates the need for separate concentric regions with strict boundaries, simplifying the overall structure while maintaining the capability to image at multiple distances.
Solution Approach 2:
The patent merges the functions of multiple concentric annular rings into a single interlaced zone pattern. Instead of having distinct nested regions (inner ring, middle ring, outer ring), the zones are combined into an integrated pattern where boundaries are less pronounced and functions are overlapping. This merging reduces structural complexity while preserving the multi-focal capability.
3Measurement precision
If lens zones of different optical powers are placed in adjacent regions, then extended depth of focus is achieved, but diffraction effects increase at zone boundaries
Solution Approach 1:
The patent transitions from a one-dimensional radial arrangement (concentric rings) to a two-dimensional interlaced pattern distributed across the aperture plane. Zones are positioned at specific angular and radial coordinates, creating a spatial distribution that reduces the concentration of diffraction effects at simple circular boundaries. This dimensional change in zone arrangement disperses diffraction patterns and reduces their impact on imaging quality.
Solution Approach 2:
The lens design applies different optical properties to specific local zones rather than uniform concentric regions. Each zone is optimized with its specific optical power and positioning to minimize local diffraction effects while contributing to the overall extended depth of focus. The local optimization of zone characteristics reduces harmful diffraction at boundaries while maintaining global optical performance.
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 achieves extended depth of focus by preventing interference and diffraction, enabling sharp imaging of objects at multiple distances without creating interference patterns, thus improving imaging clarity and contrast.
Implementation Method 1
adjacent zones are spaced apart by a distance greater than the coherence length to prevent interference and diffraction
Implementation Method 2
adjacent zones are spaced apart by a distance greater than the coherence length to prevent interference and diffraction
Data Source
AI summary
An imaging lens structure and method of imaging are presented. The imaging lens structure comprising a lens region defining an effective aperture of the lens structure. The lens region comprises an arrangement of lens zones distributed within the lens region and comprising zones of at least two different optical functions differently affecting light passing therethrough. The zones of at least two different optical functions are arranged in an interlaced fashion along said lens region corresponding to a surface relief of the lens region such that adjacent lens zones of different optical functions are spaced apart from one another along an optical axis of the lens structure a distance larger than a coherence length of light at least one spectral range for which said lens structure is designed.