Spectacle Lens Edge Rounding for Wet Coating

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Solution Overview

Problem

Conventional wet coating processes for spectacle lenses often result in paint accumulation and defects due to sharp edges between optical surfaces and cylinder edges, leading to reduced usable optical area and cosmetic failures.

Innovation Solution

The method involves rounding the transitions between the optical surfaces and the cylinder edge surfaces, allowing for smoother paint flow and gas circulation, which prevents paint accumulation and defects during coating processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional wet coating processes are used on spectacle lenses with sharp edges, then the coating process is simple and fast, but paint accumulation occurs at the edges reducing usable optical area

Engineering Contradiction:

Improvecoating process speedVSAvoidusable optical area

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

The patent applies curvature by rounding the sharp edges of spectacle lenses to create a rounded transition between the optical surface and the cylinder edge surface. This curvature prevents paint accumulation by eliminating the sharp corner effect that causes coating material to pool at edges, thereby maintaining the full usable optical area while preserving coating process efficiency

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Ease of manufacture

If conventional wet coating processes are used on spectacle lenses with sharp edges, then the coating process is simple, but defects such as air bubbles and paint cracks occur

Engineering Contradiction:

Improvecoating process simplicityVSAvoidcoating quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

By rounding the lens edges to create a curved transition zone, the patent eliminates sharp corners where air bubbles and paint cracks typically form during coating. This curvature allows for smoother paint flow and more uniform coating distribution, significantly reducing defects while maintaining process simplicity

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Manufacturing precision

If sharp edges are maintained on spectacle lenses, then manufacturing precision is easier to achieve, but paint flow is impaired causing accumulation

Engineering Contradiction:

Improveedge sharpness controlVSAvoidpaint flow behavior

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent deliberately introduces curvature at the lens edges to improve paint flow behavior. The rounded transition between optical surface and cylinder edge surface creates a smooth path for coating material, preventing accumulation and ensuring uniform distribution, thereby overriding the need for sharp edges

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 enhances manufacturing tolerance by ensuring even coating distribution, reducing paint residue, and minimizing defects such as air bubbles and paint cracks, thereby increasing the usable optical area and maintaining the lens's cosmetic quality.

Implementation Method 1

allowing for smoother paint flow and gas circulation, which prevents paint accumulation and defects during coating processes

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

allowing for smoother paint flow and gas circulation, which prevents paint accumulation and defects during coating processes

Methodology Applied

Scientific EffectGas circulation:

Data Source

PatentEP2848395B1Method for manufacturing spectacle glass semi-finished or finished product.

Publication Date: 2023.11.01 CARL ZEISS VISION INTERNATIONAL GMBH

Figure 1a~1c
Figure 1d
Figure 2

AI summary

The invention relates to a semi-finished or finished spectacle lens (200) comprising a front surface (201), a rear surface (202), a cylindrical edge surface (203), a front edge surface (204) with a front surface transition (204a) to the front surface (201) and a front cylindrical edge surface transition (204b) to the cylindrical edge surface (203), and/or a rear edge surface (205) with a rear surface transition (205a) to the rear surface (202) and a rear cylindrical edge surface transition (205b) to the cylindrical edge surface (203). The invention is characterized in that the front surface transition (204a) is rounded and/or that the rear surface transition (205a) is rounded.The invention further relates to a method for coating a semi-finished or finished spectacle lens (200) with a front surface (201), a back surface (202), a cylinder edge surface (203), a front edge surface (204) with a front surface transition (204a) to the front surface (201) and a front cylinder edge surface transition (204b) to the cylinder edge surface (203) and/or a rear edge surface (205) with a back surface transition (205a) to the back surface (202) and a rear cylinder edge surface transition (205b) to the cylinder edge surface (203), comprising the method step: wet coating the semi-finished or finished spectacle lens (200).The invention is characterized in that the front surface transition (204a) is provided with a rounding before wet coating and/or that the back surface transition (205a) is provided with a rounding before wet coating, wherein the semi-finished or finished spectacle lens product (200) is wet-coated with the front surface transition (204a) designed as a rounding and/or with the back surface transition (205a) designed as a rounding.