Ophthalmic Lens Trimming Setpoint Generation for Spectacle Frames

Solution Overview

Problem

The existing methods for mounting ophthalmic lenses in circular or half-rim spectacle frames face difficulties due to non-uniform pressure distribution on elongate frames, leading to fitting issues and the need for remachining or thread modification, which is tedious and prone to errors.

Innovation Solution

A method is proposed to generate a trimming setpoint by acquiring the shape of the frame's surround, constructing and adjusting geometrical figures, calculating differences, and selecting the closest target figure to determine the trimming setpoint, which ensures uniform pressure distribution and avoids remachining or thread modification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional machining methods are used for elongate frames, then the lens can be mounted in the surround, but non-uniform pressure distribution causes fitting issues and requires remachining or thread modification

Engineering Contradiction:

Improvefitting reliabilityVSAvoidmounting ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by characterizing the surround shape and calculating compensation values before the actual machining operation. The method determines the longitudinal profile of the surround, compares it with reference profiles, and pre-calculates the trimming setpoint with compensation values that account for non-uniform pressure distribution. This preliminary characterization and compensation calculation ensures that the lens is machined with the correct adjustments from the first attempt, eliminating the need for remachining or thread modification and ensuring proper fit on elongate frames.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If conventional trimming methods are used, then standard machining can be applied, but mounting difficulties arise due to frame shape variations

Engineering Contradiction:

Improveadaptability to frame shapesVSAvoidtrimming precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by determining that different zones of the lens edge require different trimming parameters based on the local characteristics of the surround. The method divides the surround into longitudinal zones and calculates specific compensation values for each zone based on the deviation from reference profiles. This allows the machining process to apply locally optimized trimming parameters to different segments of the lens edge, ensuring precise adaptation to the specific frame shape while maintaining overall trimming precision.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies parameter changes by dynamically adjusting the trimming setpoint parameters based on the characterized surround shape. The system acquires the longitudinal profile of the surround, compares it with reference profiles, and modifies the trimming parameters (such as edge thickness, bevel angles, and groove dimensions) according to the calculated compensation values. This parameter adaptation allows the same machining process to accurately accommodate various frame shapes while maintaining high trimming precision.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If remachining or thread modification is performed to resolve fitting issues, then proper fit can be achieved, but the process becomes tedious and error-prone

Engineering Contradiction:

Improvefitting reliabilityVSAvoidmounting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by characterizing the surround shape and calculating compensation values before the actual machining operation. The method determines the longitudinal profile of the surround, compares it with reference profiles, and pre-calculates the trimming setpoint with compensation values that account for non-uniform pressure distribution. This preliminary characterization and compensation calculation ensures that the lens is machined with the correct adjustments from the first attempt, eliminating the need for remachining or thread modification and ensuring proper fit on elongate frames.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8352065B2Method for generating a trimming setpoint for an ophthalmic lens

Publication Date: 2013.01.08 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

A method for generating a trimming setpoint for an ophthalmic lens for it to be mounted in a surround of a spectacle frame, includes:a) acquiring the shape of a first longitudinal profile of the surround,b) constructing, on a two-dimensional projection of the first longitudinal profile, at least two predetermined geometrical figures, by adjusting their dimensions to those of the two-dimensional projection,c) calculating differences between the two-dimensional projection of the first longitudinal profile and each of the predetermined geometrical figures,d) from the target geometrical figures, each of which has an associated trimming parameter, selecting the target geometrical figure that is closest to the first longitudinal profile according to the differences,e) calculating the trimming setpoint according to the shape of the first longitudinal profile and the trimming parameter associated with the selected target geometrical figure.