Water-Soluble Lens Coating for Displacement-Free Processing

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Solution Overview

Problem

High-functionality lenses with low dynamic frictional coefficients pose challenges in lens processing as conventional adhesive tapes struggle to maintain the holding position, leading to displacement issues, and existing solutions fail to meet requirements of solubility in water, transparency, and preservation of water repellency.

Innovation Solution

A displacement prevention coating agent composed of an aqueous solution with a hydrophilic resin, a surfactant having a perfluoro group, and a particulate transparent resin composition, which forms a membrane that enhances holding stability and is soluble in water, maintaining transparency and water repellency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a normal adhesive tape is used to hold the lens, then the holding position is maintained, but the lens displacement cannot be prevented due to low dynamic frictional coefficient and adhesion-preventing properties of the coat layer

Engineering Contradiction:
Improveholding position stabilityVSAvoidlens handling during processing
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention changes the surface parameters of the lens by forming a displacement prevention coat layer with specific properties: surface tension of 20 mN/m or more (higher than the water-repellent coat layer), and dynamic frictional coefficient of 0.30 or more (higher than the water-repellent coat layer). These parameter changes enable the adhesive tape to effectively hold the lens without displacement while maintaining the functionality of the underlying coat layer.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure consisting of two distinct coat layers: a water-repellent coat layer (with low surface tension and low dynamic frictional coefficient) and a displacement prevention coat layer (with higher surface tension and higher dynamic frictional coefficient). This composite material approach allows both layers to coexist and perform their respective functions simultaneously.

Inventive Principle:
Principle #40Composite materials

2Reliability

If an adhesive tape with enhanced adhesion is used to prevent lens displacement, then the holding position stability improves, but cost and handleability deteriorate

Engineering Contradiction:
Improveholding position stabilityVSAvoidcost and handleability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of changing the adhesive tape properties, the invention changes the lens surface properties by forming a displacement prevention coat layer with controlled surface tension (20-40 mN/m) and dynamic frictional coefficient (0.30-0.60). This allows the use of normal adhesive tapes with standard adhesion, cost, and handleability characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The displacement prevention coat layer acts as an intermediary between the water-repellent coat layer and the adhesive tape. It provides the necessary friction and adhesion for the adhesive tape to hold the lens effectively, while allowing the water-repellent coat layer to maintain its functionality underneath.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the coat layer functionality is enhanced with water repellency, oil repellency, low frictional properties, and adhesion-preventing properties, then lens performance improves, but the difficulty of adhering tape increases and dynamic frictional coefficient decreases

Engineering Contradiction:
Improvelens performanceVSAvoidtape adhesion and lens handling
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention applies different properties to different layers: the water-repellent coat layer provides water repellency, oil repellency, and low frictional properties for lens performance; the displacement prevention coat layer provides higher surface tension and higher dynamic frictional coefficient for tape adhesion and handling. Each layer has localized quality optimized for its specific function.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention creates a composite coat structure where the water-repellent coat layer and displacement prevention coat layer work together. The water-repellent coat layer provides high-functionality lens performance, while the displacement prevention coat layer provides improved tape adhesion and handling characteristics.

Inventive Principle:
Principle #40Composite materials

4Object-affected harmful factors

If a coating agent soluble in water is used to avoid staining and damage, then the lens and processing equipment are protected, but the coating agent must be removed after processing which adds operational steps

Engineering Contradiction:
Improvestaining and damage preventionVSAvoidprocessing steps
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention uses a water-soluble coating agent (with water solubility of 10 g/L or more) for the displacement prevention coat layer. This parameter change allows the coating to be easily removed by washing with water after processing, preventing staining and damage to the lens and equipment, though it does require an additional removal step.

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

The coating agent effectively prevents lens displacement during processing by forming a stable, elastic membrane that maintains transparency and water repellency, ensuring accurate lens shaping without compromising the lens's optical properties.

Implementation Method 1

A surface tension on a water-repellent lens surface is lowered to show sufficient wettability

Methodology Applied
Scientific EffectSurface tension reduction: Surface Tension

Implementation Method 2

A surface tension on a water-repellent lens surface is lowered to show sufficient wettability

Methodology Applied
Scientific EffectWettability enhancement: Wetting

Implementation Method 3

a coat layer is provided which has... low frictional properties for further reducing the resistance of a lens surface at the time of wiping

Methodology Applied
Scientific EffectFriction enhancement: Friction

Implementation Method 4

a particulate transparent resin composition that is insoluble in water and exhibits a transparent appearance at least after the formation of the membrane

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 5

When the coating agent formed as a membrane is insoluble in water, since this becomes a factor for staining the interior of a cutting device at the time of cutting or damaging the lens, the coating agent needs to be soluble in water

Methodology Applied
Scientific EffectSolubility: Solvation

Data Source

PatentUS9963612B2Displacement prevention coating agent
Publication Date: 2018.05.08 TOKAI OPTICAL CO LTD

AI summary

A displacement prevention coating agent is provided which can prevent a displacement in lens processing, which is soluble in water and which exhibits a transparent appearance at least after being cured. The displacement prevention coating agent may coat the front and rear surfaces of a lens so that when cutting processing is performed on an end surface of the lens, a holding position of the front and rear surfaces of the lens held by a chuck device is prevented from being displaced. A water-repellent coat layer may be formed as a membrane such that the end surface has a shape corresponding to a frame. The displacement prevention coating agent may be formed of an aqueous solution whose main components are a hydrophilic resin, a surfactant having a perfluoro group and an emulsion.