Ophthalmic Lens Deblocking via Controlled Pushing Force

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Solution Overview

Problem

The deblocking process of ophthalmic lenses from thermoplastic blocking materials is time-consuming and can introduce defects, particularly due to the need for a hammering step that may crack the interface between the thermoplastic and the lens blank or tape, requiring improvement to enhance lens quality.

Innovation Solution

Applying a pushing force of 100 N to 1000 N at a distance of at least 17.5 mm from the fitting or prism reference point of the lens, with optional warming of the thermoplastic layer to reduce the moment applied and minimize stress, allowing for efficient separation without damaging the lens.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a hammering step is used to separate the lens blank from the thermoplastic blocking material, then the deblocking process can be completed, but cracks may be generated at the interface between the thermoplastic and the lens blank or tape

Engineering Contradiction:
Improvedeblocking speedVSAvoidlens quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces the traditional mechanical hammering method with a thermal field method. By applying heat to the thermoplastic blocking material, the material softens and releases the lens blank automatically, eliminating the need for mechanical impact that causes cracks. This substitution of mechanical action with thermal action resolves the contradiction between deblocking efficiency and lens quality.

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

Solution Approach 2:

The patent changes the physical state of the thermoplastic blocking material by altering its temperature parameter. Heating the thermoplastic material above its glass transition temperature transforms it from a rigid state to a soft, pliable state, enabling automatic release of the lens blank without mechanical force. This parameter change allows deblocking to occur without the harmful hammering step.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the pushing force is applied close to the fitting point or prism reference point, then the separation may be more effective, but the moment applied to the lens increases causing deformation

Engineering Contradiction:
Improveseparation effectivenessVSAvoidlens deformation
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical pushing force system with a thermal field system. Instead of applying force at various locations on the lens, heat is applied to the thermoplastic material, which then releases the lens uniformly. This eliminates the moment creation problem entirely by removing the mechanical force application point, thus preventing lens deformation while achieving effective separation.

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

Solution Approach 2:

The patent introduces thermal energy as an intermediary between the operator and the lens blank. Rather than directly applying mechanical force to the lens, heat serves as the intermediary that acts on the thermoplastic material, which in turn releases the lens. This indirect action through a thermal intermediary avoids creating harmful moments on the lens.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the thermoplastic layer is not warmed before deblocking, then the process is simpler, but the moment applied to the lens increases causing more stress and potential damage

Engineering Contradiction:
Improvedeblocking process complexityVSAvoidlens integrity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies a controlled temperature parameter change to the thermoplastic blocking material. By heating the material to above its glass transition temperature, the material's physical properties change, allowing it to release the lens blank without requiring high mechanical forces. This controlled parameter change enhances lens integrity while adding only minimal process complexity through simple heating.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs a preliminary heating action on the thermoplastic blocking material before the actual deblocking occurs. This preliminary thermal treatment softens the material in advance, so that when deblocking happens, the material is already in a state that minimizes stress on the lens. This preliminary action prevents damage while maintaining process simplicity.

Inventive Principle:
Principle #10Preliminary action

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

This method improves the deblocking process by reducing the risk of deformation and defects, enabling faster and more precise separation of the lens from the thermoplastic block while maintaining the optical quality of the lens.

Implementation Method 1

with optional warming of the thermoplastic layer to reduce the moment applied and minimize stress

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

Applying a pushing force of 100 N to 1000 N at a distance of at least 17.5 mm from the fitting or prism reference point

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP2498950B1Lens deblocking method
Publication Date: 2014.12.03 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP2498950B1 patent drawingFigure 1~3
  • EP2498950B1 patent drawingFigure 4~5

AI summary

A method of deblocking an ophthalmic lens component (100) blocked on a thermoplastic layer (310) arranged on the holding surface (210) of a lens holding block (200) comprising the step of applying a pushing force on the thermoplastic layer (310), wherein the pushing force is greater or equal to 100 N and smaller or equal to 1000 N and wherein the pushing force is applied in a region of the thermoplastic layer (310) situated at a distance of at least 17.5 mm from the fitting point or prism reference point of the ophthalmic lens component (100).