Progressive Power Lens Thickness Distribution Design

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Solution Overview

Problem

The existing methods for manufacturing progressive power lenses using semi-finished lenses limit the degree of freedom in thickness distribution, as the shape of the object-side surface determines the eyeball-side surface, restricting the design of the correction surface and reducing the flexibility in lens thickness at various positions.

Innovation Solution

A method that calculates and adjusts the curve data for both the object-side and eyeball-side surfaces of progressive power lenses under specific prescription conditions to determine multiple sets of curve data, allowing for the calculation of thickness at various positions that satisfy predetermined thickness conditions, thereby increasing the freedom in lens thickness distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a semi-finished lens with a fixed object-side surface is used, then the manufacturing process is simplified, but the degree of freedom in lens thickness distribution is reduced

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidlens thickness distribution freedom

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The lens design is divided into two independent surfaces: the object-side surface and the eyeball-side surface. Each surface can be optimized separately, allowing the object-side surface to maintain its standardized semi-finished form while the eyeball-side surface is customized to achieve desired thickness distribution. This segmentation enables independent optimization of manufacturing simplicity and thickness adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from designing only the correction surface (eyeball-side) to independently designing both the object-side surface and correction surface. By adding the dimension of object-side surface design freedom, the system gains additional control over thickness distribution without compromising manufacturing simplicity, as standardized semi-finished lenses can still be used as starting materials.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If the object-side surface is fixed as a reference surface, then the design process is simplified, but the flexibility in correcting astigmatism and optimizing thickness is limited

Engineering Contradiction:

Improvedesign process complexityVSAvoidcorrection surface design flexibility

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The design approach evolves from a static reference surface model to a dynamic dual-surface optimization model. While the object-side surface can remain fixed for simplicity, the system dynamically adjusts the eyeball-side surface design based on specific prescription requirements, allowing flexible adaptation to different astigmatism corrections and thickness preferences without increasing overall design complexity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention introduces additional design parameters by allowing independent modification of the object-side surface curvature in addition to the correction surface. This parameter expansion provides more degrees of freedom for optimizing thickness distribution and astigmatism correction, while the systematic design methodology keeps the overall process complexity manageable.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If the eyeball-side surface is calculated based on a predetermined base curve section, then manufacturing standardization is improved, but the degree of freedom in thickness at each position is reduced

Engineering Contradiction:

Improvelens manufacturing standardizationVSAvoidthickness distribution freedom

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Standardized semi-finished lenses with predetermined base curve sections are prepared in advance as starting materials. This preliminary standardization maintains manufacturing precision and efficiency, while subsequent customization of the eyeball-side surface design provides the necessary flexibility for individual thickness distribution requirements without compromising the standardized foundation.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10386652B2Lens design method, lens manufacturing method, storage medium, and lens design system

Publication Date: 2019.08.20 NIKON ESSILOR

AI summary

A lens design method includes: changing curve data including a curve value of a distance vision part and a curve value of a near vision part of a progressive power lens on an object side and a curve value of a distance vision part and a curve value of a near vision part of the progressive power lens on an eyeball side so as to be suited to prescription values to calculate a plurality of sets of the curve data; and calculating, for each of the calculated sets of the curve data, a thickness at a second position on the progressive power lens that satisfies thickness conditions for a first position on the progressive power lens.