Multi-Contact Diffractive Spectacle Lens for Chromatic Aberration
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Solution Overview
Problem
Conventional diffractive optical elements in spectacle lenses are limited by high manufacturing costs and are not suitable for mass production, as they often result in reduced image quality due to flare issues at wavelengths other than the specified design wavelength.
Innovation Solution
A multi-contact diffractive optical element is designed with specific refractive index differences and diffraction efficiencies for d-, g-, and C-lines, combined with a meniscus lens system, where the multi-contact diffractive optical element is formed on either the object or pupil side to correct chromatic aberration, and the materials are selected to optimize diffraction efficiency and mass producibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional diffractive optical elements are used in spectacle lenses, then chromatic aberration can be corrected at a specified wavelength, but flare occurs at other wavelengths resulting in reduced image quality
Solution Approach 1:
The patent divides a single diffractive optical element into multiple diffractive optical elements with different design wavelengths. Each element is optimized for a specific wavelength range, and their combined effect covers a broader spectral band while minimizing flare across all wavelengths.
Solution Approach 2:
The patent changes the design parameters of multiple diffractive optical elements to target different wavelengths. By varying the grating depth, period, and material properties across elements, the system achieves wideband chromatic aberration correction without the flare issues of single-wavelength designs.
2Measurement precision
If conventional diffractive optical elements are used to correct chromatic aberration, then image quality improves at the design wavelength, but manufacturing cost increases making mass production difficult
Solution Approach 1:
The patent combines multiple diffractive optical elements into a single integrated spectacle lens structure. This merging approach maintains the chromatic aberration correction benefits while enabling mass production through standardized manufacturing processes for ophthalmic lenses.
Solution Approach 2:
The patent uses composite material structures where diffractive patterns are integrated into lens materials with specific refractive index profiles. This allows the diffractive elements to be manufactured using standard lens fabrication techniques rather than requiring separate, expensive manufacturing processes.
3Weight of moving object
If a single lens is used for the spectacle, then size and weight are reduced, but achromatism (correction of chromatic aberration) cannot be achieved
Solution Approach 1:
The patent makes a single spectacle lens perform multiple functions: refractive correction, chromatic aberration correction across wide bandwidth, and flare reduction. The diffractive optical elements embedded in the single lens provide achromatism without requiring additional separate optical components.
Solution Approach 2:
The patent adds diffractive optical features to the traditional refractive lens design. By incorporating micro-scale diffraction gratings into the lens structure, the system achieves chromatic aberration correction in the optical dimension while maintaining the physical simplicity of a single lens element.
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 provides a spectacle lens with high performance and excellent mass producibility, effectively correcting chromatic aberration and reducing flare across a wide spectral band, while maintaining a compact and lightweight design.
Implementation Method 1
a diffraction efficiency Ed with respect to a d-line of the multi-contact diffractive optical element, a diffraction efficiency Eg with respect to a g-line, and a diffraction efficiency EC with respect to a C-line satisfy (Eg+EC)/2>0.9×Ed
Implementation Method 2
a refractive index difference ΔNd with respect to a d-line between two layers of the multi-contact diffractive optical element in close contact with each other satisfy
Data Source
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AI summary
The present invention has an object to provide a spectacle lens with high performance and excellent in mass producibility. To achieve this, a spectacle lens of the present invention includes a multi-contact diffractive optical element formed on at least one surface (SA or SB) of a overall lens system (L1) that is arranged from an object to a pupil, in which an apparent Abbe number Vd when the overall lens system including the multi-contact diffractive optical element is regarded as a single lens satisfies Vd>60 ... (1). The spectacle lens in which the multi-contact diffractive optical element is used in this manner has high performance and also high mass producibility.