Multifocal Diffractive Lens Using Negative-Order Far Focus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multifocal diffractive lenses experience a mismatch in focal positions between monochromatic and polychromatic performance evaluations, leading to inefficient use of light as the focal point for far vision is often located behind the retina, causing misalignment and reduced efficiency in polychromatic conditions.
Innovation Solution
A multifocal diffractive lens design that includes a diffraction grating with negative-order light producing a focal point for far vision closer to the lens than 0-order light, allowing efficient light use by aligning the focal point for far vision in polychromatic performance closer to the lens than in monochromatic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional multifocal diffractive lenses are designed based on monochromatic performance evaluation at 546±10 nm wavelength, then the focal position for far vision is determined for monochromatic light, but the focal position shifts in polychromatic conditions causing the focal point to be located behind the retina and light to be used inefficiently
Solution Approach 1:
The patent changes the optical design parameters by using negative-order diffracted light instead of conventional positive-order light for far vision focus. This parameter change causes the focal position in polychromatic conditions to shift toward the lens, bringing it closer to the retina and improving light utilization efficiency while maintaining monochromatic measurement accuracy
2Reliability
If the focal position for far vision is set based on monochromatic evaluation, then the lens meets specification requirements for monochromatic performance, but the focal position mismatch causes hyperopia in white light environments and reduces actual performance
Solution Approach 1:
The patent inverts the conventional approach by using negative-order diffracted light (−1 order) instead of positive-order light for far vision focus. This inversion changes the direction of chromatic aberration, causing the focal position in polychromatic light to shift toward the lens rather than away from it, thereby preventing hyperopia while maintaining monochromatic specification compliance
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 ensures that the focal point for far vision in polychromatic conditions is located nearer to the lens than in monochromatic conditions, enabling efficient light use and preventing hyperopia in white light environments by aligning focal positions correctly.
Implementation Method 1
Conventional multifocal diffractive lenses are often configured to focus 0-order light (refracted light) at a focal point for far vision and focus +1-order light (diffracted light) at a focal point for near vision or intermediate vision
Implementation Method 2
A multifocal diffractive lens according to the present invention includes a diffraction grating. Negative-order light produces a focal point for far vision while 0-order light produces a focal point nearer to the multifocal diffractive lens than that of the far vision
Implementation Method 3
Conventional multifocal diffractive lenses are often configured to focus 0-order light (refracted light) at a focal point for far vision and focus +1-order light (diffracted light) at a focal point for near vision or intermediate vision
Data Source
AI summary
A multifocal diffractive lens is provided which achieves efficient use of light. The multifocal diffractive lens 100 includes a diffraction grating 1c. Negative-order light L2 produces a focal point f2 for far vision and 0-order light L1 produces a focal point f1 nearer to that for far vision. The number of focal points is two or more. The focal position fc for far vision in polychromatic performance evaluation is located nearer to the multifocal diffractive lens than the focal position fs for far vision in monochromatic performance evaluation.