Ophthalmic Lens Debloating Using Warm Gas and Pushing Strain

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Solution Overview

Problem

The existing methods for deblocking ophthalmic lenses from thermoplastic blocks are time-consuming and can introduce defects, particularly due to the need for a hammering step which may crack the lens interface.

Innovation Solution

A method involving a pushing strain of 0.1 to 1 MPa combined with a warm gas flow at the interface between the lens component and the thermoplastic block, with temperatures between 30°C and 70°C and humidity between 75% and 100%, allowing for progressive decohesion without the need for a lens impact damper.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional hammering method is used for deblocking, then the lens component can be removed from the thermoplastic block, but the lens interface may be cracked and the process is time-consuming

Engineering Contradiction:

Improvedeblocking speedVSAvoidlens interface quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces the traditional mechanical hammering system with a thermal system. A heating element is inserted through the lens component into the thermoplastic block, and heat is applied to soften the thermoplastic material, enabling automatic deblocking without mechanical impact. This substitution eliminates the harmful hammering action while maintaining effective lens removal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the temperature parameter of the thermoplastic block by applying localized heat through a heating element. By raising the temperature above the glass transition temperature of the thermoplastic material, the material transitions from a rigid state to a softened state, allowing the lens component to be deblocked without mechanical force that could cause cracking.

Inventive Principle:

Principle #35Parameter changes

2Strength

If low temperature metal alloys are used for lens blocking, then the lens blank can be securely held, but environmental and health hazards are created during preparation and reclamation

Engineering Contradiction:

Improvelens holding strengthVSAvoidenvironmental and health hazards

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent employs a disposable thermoplastic blocking material that is molded into a lens block form. This material is used for a single blocking operation and then discarded after the lens is processed and removed. The disposable nature eliminates the need for complex reclamation processes associated with metal alloys, thereby eliminating environmental and health hazards related to alloy preparation and recovery.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses thermoplastic materials, which are organic polymers, as an alternative to metal alloy composites. These thermoplastic blocking materials provide sufficient holding strength through adhesion and mechanical interlocking, while being environmentally benign and safe for worker health during preparation and disposal.

Inventive Principle:

Principle #40Composite materials

3Strength

If glues or pitch are used for lens blocking, then the lens blank can be adhered to the lens block, but the materials are messy and non-reusable

Engineering Contradiction:

Improvelens adhesion strengthVSAvoidmaterial cleanliness and reusability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent utilizes the temperature-dependent properties of thermoplastic materials. At room temperature, the thermoplastic blocking material is solid and provides strong adhesion to the lens blank. During the deblocking process, localized heating softens the thermoplastic material, reducing its adhesion strength and allowing the lens to be easily removed. This parameter change enables both strong initial adhesion and easy subsequent removal without mess or damage.

Inventive Principle:

Principle #35Parameter changes

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 approach enables soft deblocking with preserved lens quality, avoiding the defects and time consumption associated with traditional methods, and allows for rapid and low-strain deblocking of the lens component.

Implementation Method 1

providing a warm gas flow at the interface between the lens component and the thermoplastic block, with temperatures between 30°C and 70°C

Methodology Applied

Scientific EffectThermal heating: Heating

Data Source

PatentUS9174321B2Lens blocking and deblocking method and related device

Publication Date: 2015.11.03 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

A method of deblocking a lens component (1) fixed on a thermoplastic block (2) of an ophthalmic lens block comprising the steps of: a) applying a pushing strain on the surface (14) of the lens component fixed on the thermoplastic block; b) providing a warm gas flow at the interface between the lens component (1) and the thermoplastic block; and maintaining the pushing strain during the step of providing the warm gas flow at the interface between the lens component and the thermoplastic block, wherein the stress applied to obtain the pushing strain of step a) is greater or equal to 0.1 MPa and/or less or equal to 1 Mpa, and wherein the temperature of the warm gas flow of step b) is greater or equal to 30° and/or less or equal to 70° C.