Multifocal Eyeglass with Alternating Vision Zones
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Solution Overview
Problem
Current multifocal and progressive eyeglasses are inadequate for situations requiring vision correction at varying distances, particularly causing poor visual perception of objects on the ground or at different heights, due to chromatic aberrations and inefficient light convergence, leading to potential accidents.
Innovation Solution
A method for producing multifocal eyeglasses with a principal vision zone for optimal correction at a primary distance and a secondary vision zone divided into alternating regions for multiple secondary distances, eliminating chromatic aberrations by ensuring all light converges appropriately, providing clear vision across different distances without the need for head or eye orientation adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional multifocal or progressive eyeglasses are used to provide ophthalmic correction for multiple vision distances, then the wearer can see clearly at near vision distance (e.g., reading a book), but the wearer experiences poor visual perception of objects at intermediate distances (e.g., ground obstacles, wall scripts) and must constantly adjust head and eye orientation
Solution Approach 1:
The lens is divided into multiple distinct zones: a first zone for near vision correction, a second zone for intermediate distance correction, and a third zone for far vision correction. Each zone contains specific optical power values tailored to its intended viewing distance, allowing the wearer to access appropriate correction for different distances without constant head or eye orientation adjustments.
Solution Approach 2:
Different regions of the lens are assigned different optical properties (power values) according to their function. The first zone has optical powers optimized for near vision, the second zone has powers for intermediate distances, and the third zone has powers for far vision. This local differentiation ensures each area of the lens provides the appropriate correction for its specific viewing distance.
2Adaptability or versatility
If diffractive effects are used to provide multiple focal distances simultaneously, then the eyeglass can correct vision at different distances, but significant chromatic aberrations occur and contrast is reduced
Solution Approach 1:
Instead of using diffractive effects that inherently produce chromatic aberration, the patent segments the lens into distinct zones with different optical powers. Each zone is designed with specific spherical and cylindrical power values appropriate for its viewing distance, avoiding the chromatic separation problems associated with diffraction while still providing multiple focal corrections.
Solution Approach 2:
The patent replaces the optical mechanism of diffraction (which causes chromatic aberration) with a zonal power distribution system. Rather than relying on light diffraction to create multiple focal points, the lens uses spatially varying refractive powers in different zones, substituting a refractive mechanism for a diffractive one to eliminate chromatic problems while maintaining multifocal functionality.
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 eyeglasses offer clear and optimal vision for multiple distances without significant chromatic aberrations, enhancing safety and comfort by ensuring maximum contrast and clarity for presbyopic wearers, regardless of the object's distance or direction, similar to unifocal correction.
Implementation Method 1
multifocal or progressive eyeglasses which have different optical powers between distinct parts of these eyeglasses
Data Source
AI summary
A multifocal ophthalmic eyeglass (1) corrects a wearer's vision for a first vision distance in a principal vision zone (10) of the eyeglass, and for at least two different second vision distances in a secondary vision zone (20) of said eyeglass. For this purpose, the secondary vision zone is divided into at least two series of alternating regions, each producing an ophthalmic correction suitable for one of the second vision distances. A presbyopic wearer provided with such an eyeglass can both read a book and view an obstacle on the ground equally well, for the same direction of his gaze through the secondary vision zone.