Optical Lens Blank Positioning Ring for Rear-Face Machining Accuracy

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Solution Overview

Problem

Existing methods for manufacturing optical lenses face challenges in accurately positioning the rear face relative to the front face during machining, leading to potential positioning errors that can affect the quality of the lens.

Innovation Solution

The method employs mechanical positioning and control markers on the puck and ring to securely position the puck without the need for subsequent verification by an operator or camera, ensuring precise alignment in all directions of translation and rotation, thereby eliminating or minimizing positioning errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visual control markers and camera verification are used to position the puck on the ring, then positioning accuracy can be verified, but the process becomes more complex and time-consuming

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpositioning process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces optical verification systems (camera and visual markers) with a purely mechanical positioning system. The puck includes mechanical positioning markers (circular edge, chamfered portion) that directly engage with corresponding mechanical control markers on the ring (internal contour, shoulder). This mechanical engagement automatically ensures precise positioning without requiring camera verification or complex visual alignment procedures.

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

Solution Approach 2:

The positioning system is designed to be self-aligning and self- verifying through mechanical constraints. The circular edge of the puck fits into the internal contour of the ring, and the chamfered portion engages with the shoulder, creating automatic geometric constraints that ensure correct positioning. The system self-verifies through the physical fit of these mechanical markers without requiring external verification devices.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If mechanical positioning markers are used to secure the puck on the ring, then positioning precision is improved, but the device complexity increases

Engineering Contradiction:
Improvepositioning precisionVSAvoidmarker system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of using complex positioning mechanisms across the entire puck surface, the patent applies localized geometric features at specific positions. The circular edge and chamfered portion are localized mechanical markers on the puck that engage with corresponding localized features (internal contour and shoulder) on the ring. This localized approach achieves precise positioning without requiring complex systems throughout the entire device.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses asymmetric geometric features to achieve precise positioning. The chamfered portion with its specific angle creates a unique asymmetric engagement with the shoulder of the ring, preventing rotation and ensuring correct orientation. The circular edge provides symmetric radial positioning, while the chamfer provides asymmetric angular constraint, together achieving complete six-degree-of-freedom positioning through simple geometric asymmetry rather than complex mechanisms.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP2914399B1Method for manufacturing optical lenses and assembly for manufacturing such lenses
Publication Date: 2022.03.02 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP2914399B1 patent drawingFigure 1~3
  • EP2914399B1 patent drawingFigure 4~8
  • EP2914399B1 patent drawingFigure 9~10

AI summary

The invention relates to a method for manufacturing an optical lens, comprising the steps of providing a blank (1) which comprises an upper surface and a lower surface (33) for forming first and second lens surfaces (2), an edge surface (4) forming a first mechanical positioning reference point and a ramp portion (5) provided between said edge surface and said upper surface, which forms a second positioning reference point; providing a positioning ring (10) comprising a cavity defining an inner contour (20) concentric with said edge surface which forms a first complementary control reference point and a shoulder (21) forming a second complementary control reference point; fitting said blank into said cavity, said edge surface being in contact with said inner contour and said ramp portion being in contact with said shoulder; and locking said blank in position on a locking and supporting pin, said ring then being positioned therebetween.