Diffractive Lens Manufacturing Method for Stable Multi-Focusing
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Solution Overview
Problem
Conventional diffraction lenses for presbyopia struggle to maintain multi-focusing effects due to aperture changes and lens eccentricity, leading to reduced contrast in intermediate vision ranges.
Innovation Solution
A diffraction lens with a novel manufacturing method featuring a relief pattern where first order diffracted lights from multiple reliefs overlap, with grating pitches synchronized to achieve distinct focal points for far, near, and intermediate vision, reducing stray light and glare.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple areas with different reliefs are formed in the lens radial direction to generate more foci, then the number of foci increases, but the focal effect becomes unstable when aperture or pupil diameter varies
Solution Approach 1:
The lens is divided into multiple radial areas, each containing reliefs with different grating pitches. Each area generates diffracted light for specific vision ranges (distance, intermediate, near), allowing multiple foci to be created while maintaining stable optical performance across varying aperture conditions.
2Ease of manufacture
If conventional diffraction lens design is used, then manufacturing is simple, but intermediate vision contrast is too low
Solution Approach 1:
Different radial areas of the lens are assigned different relief characteristics with specific grating pitches optimized for particular vision ranges. This local differentiation enhances intermediate vision contrast by directing appropriate amounts of diffracted light to the intermediate focus while maintaining overall manufacturing feasibility through systematic pattern design.
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 method ensures stable multi-focusing effects across varying apertures and lens positions, enhancing vision clarity and contrast in intermediate ranges while maintaining focus for far and near vision.
Implementation Method 1
a diffraction lens such as that disclosed in Patent Literature 1, for example, is provided with a diffraction grating having a relief on the lens surface, and is allowed to form two foci by the Oth order light and first order diffracted light taking advantage of the diffraction phenomenon of light that passes through the relief
Data Source
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AI summary
Provided is a novel manufacturing method for a diffraction lens, whereby aperture and eccentricity effects can be suppressed and any multi-focusing effect can also be obtained in a more stable manner. A synchronous structure is set up where at least two reliefs (32, 34) whose first order diffracted lights give respective focal distances different from one another are set to overlap with each other in at least a part of an area in a radial direction of a diffraction lens (10), and with respect to every grating pitches of one relief (34) having the maximum grating pitch among the reliefs (32, 34) set up in overlap, grating pitches of another relief (32) are overlapped periodically; and the resulting relief pattern (30) is formed on a surface (24) of an optical material (10).