Eyeglass Lens Defocus Region Layout to Suppress False Focusing
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Solution Overview
Problem
Existing eyeglass lenses with hyperopia reducing functions suffer from false focusing in front of the retina, which hinders the hyperopia reducing effect and compromises wearing comfort.
Innovation Solution
The eyeglass lens design includes a base region for converging light at a predetermined position on the retina and defocus regions that converge light farther behind the retina, with a diameter ratio d1/d2 between 2 and 3, ensuring the defocus regions are spaced apart and have a specific area ratio, and a spherical shape to suppress false focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If defocus regions are provided in a normal prescribed lens surface to achieve hyperopia reducing function, then hyperopia reducing effect is improved, but false focusing in front of the retina occurs which hinders the hyperopia reducing effect and compromises wearing comfort
Solution Approach 1:
The patent applies local quality by creating defocus regions with specific local optical characteristics (spherical shape, controlled diameter) that differ from the base lens surface. These localized regions with radius of curvature R1 and diameter d2 are strategically positioned to provide hyperopic defocus while controlling false focusing through precise local geometry design.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the geometric parameters of defocus regions: the ratio d1/d2 between 2 and 3, the spherical shape with specific radius of curvature, and the spacing between regions. These parameter optimizations ensure that light converges at the desired position behind the retina while minimizing false focusing in front of the retina.
2Reliability
If defocus regions are made larger to enhance hyperopia reducing effect, then the hyperopia reducing function is improved, but the lens appearance is compromised and wearing comfort is reduced
Solution Approach 1:
The patent optimizes the size parameters of defocus regions by controlling the diameter d2 and the ratio d1/d2 within specific ranges. This parameter optimization ensures sufficient hyperopic defocus effect while keeping the defocus regions small enough to maintain natural lens appearance and wearing comfort, avoiding excessive visual distortion.
Solution Approach 2:
The patent applies spheroidality by designing defocus regions with spherical surfaces and specific radii of curvature. This curved geometry provides effective optical defocus while maintaining a smooth, natural appearance on the lens surface, avoiding the visual disruption that would result from flat or irregularly shaped regions.
3Reliability
If defocus regions are arranged closely together to increase the area ratio, then the hyperopia reducing effect is enhanced, but false focusing increases and wearing comfort deteriorates
Solution Approach 1:
The patent applies local quality by creating defocus regions with specific local optical characteristics (spherical shape, controlled diameter) that differ from the base lens surface. These localized regions with radius of curvature R1 and diameter d2 are strategically positioned to provide hyperopic defocus while controlling false focusing through precise local geometry design.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the geometric parameters of defocus regions: the ratio d1/d2 between 2 and 3, the spherical shape with specific radius of curvature, and the spacing between regions. These parameter optimizations ensure that light converges at the desired position behind the retina while minimizing false focusing in front of the retina.
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 effectively suppresses false focusing, enhances the hyperopia reducing effect, and improves wearing comfort by ensuring the defocus regions' arrangement and shape contribute to the main peak on the retina, reducing discomfort and maintaining lens appearance.
Implementation Method 1
a base region configured to cause light incident on an object-side surface to exit from an eye-side surface, enter an eye, and converge at a predetermined position A on a retina
Implementation Method 2
a plurality of defocus regions having a characteristic of causing light to converge at a position B farther from an object side than the position A is
Data Source
AI summary
An eyeglass lens including a base region that causes light incident on an object-side surface to exit from an eye-side surface, enter an eye, and converge at a predetermined position A on a retina, and a plurality of defocus regions having a characteristic of causing light to converge at a position B farther from an object side than the position A is. Also, d1/d2 is greater than 2 and less than 3, where d1, which is the diameter of a circle circumscribing a triangle connecting centers of three of the defocus regions closest to each other, is divided by d2, which is the diameter of the defocus regions.