Optical Lens Machining Using Reference Elements for Surface Alignment

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Solution Overview

Problem

Existing methods for manufacturing optical lenses fail to accurately maintain the relative position of the optical surfaces during machining, leading to potential optical errors due to issues like blocker adjustment, wear, and clearance, especially for asymmetrical designs.

Innovation Solution

A method involving a semi-finished lens with a reference element on the second optical surface, detectable optically or mechanically, and a machining device with a position tool to determine and maintain the precise positioning of the first and second optical surfaces using a machining reference system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If engraved markings are used on the finished face to define the reference system during blocking, then the reference system is established, but the positioning accuracy deteriorates due to blocker adjustment, wear, and clearance issues

Engineering Contradiction:
Improvereference system establishmentVSAvoidrelative position of optical surfaces
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent creates a digital copy of the reference system by detecting the engraved markings with a position tool and transferring their coordinates to a computer. This digital replica allows precise positioning without being affected by physical wear or adjustment errors of the blocking device, resolving the contradiction between establishing a reference system and maintaining positioning accuracy

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical reference system (physical blocking device with engraved markings) with a computerized system that detects and processes the markings digitally. This substitution eliminates mechanical wear and adjustment errors, maintaining measurement precision while improving manufacturing precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the blocking device is used to maintain the position of the semi-finished lens, then the lens is secured during manufacturing, but positioning accuracy deteriorates due to wear of reference components and clearance between housing and insert

Engineering Contradiction:
Improvelens securingVSAvoidposition of optical surfaces
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent creates a digital copy of the lens position relative to the blocking device by detecting reference markings and transferring coordinates to a computer. This digital replica allows precise positioning without being affected by physical wear or clearance issues in the mechanical blocking system

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent implements a feedback loop where the position tool detects the actual position of reference markings on the lens, the computer processes this information, and the machining tool adjusts accordingly. This closed-loop feedback compensates for wear and clearance in the blocking device, maintaining both reliability and precision

Inventive Principle:
Principle #23Feedback

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

Enhances the accuracy of surface positioning, reducing optical errors and ensuring the desired refractive properties of the final lens.

Implementation Method 1

a reference element 20 on the second optical surface 14 to be manufactured, wherein the reference element 20 is detectable by a position tool of the machining device

Methodology Applied
Scientific EffectOptical detection:

Data Source

PatentEP3628441B1Method and device for manufacturing an optical lens
Publication Date: 2026.02.11 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP3628441B1 patent drawingFigure 1~2
  • EP3628441B1 patent drawingFigure 3~4
  • EP3628441B1 patent drawingFigure 5~6

AI summary

The invention concerns a semi-finished lens (10) comprising a first optical surface (12) comprising a surface design associated with a first reference system and a second optical surface (14) to be manufactured, the first and second optical surfaces are connected by an external periphery surface (16), the semi-finished lens further comprising a reference element (20) provided on the second optical surface (14) and/or on the external periphery surface (16), the position of the reference element (20) being defined with respect to the first reference system. The invention also relates to a method and a device for manufacturing an optical lens from such a semi-finished lens.