Glass-Ceramic Plate Nanometric Coating for Reflective Appearance

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Solution Overview

Problem

Current glass-ceramic cooking plates face challenges in achieving a balanced aesthetic and functional appearance with reflective zones in a simpler and more cost-effective manner, as existing coatings are either expensive, complex to manufacture, or limited to specific types of heating elements and temperatures.

Innovation Solution

A nanometric layer based on metallic materials with a refractive index higher than glass-ceramic, such as aluminum oxide, titanium dioxide, or iron oxide, is applied to the glass-ceramic plate before ceramization using a sol-gel composition, which can be deposited by screen printing and withstands high temperatures, providing a reflective appearance without compromising the plate's mechanical or thermal properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If reflective layers are deposited by magnetron sputtering, then reflective appearance is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvereflective appearanceVSAvoidmanufacturing complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent replaces expensive magnetron sputtering with a simpler, more cost-effective sol-gel process using commercially available effect pigments. This substitutes a complex industrial deposition process with a more accessible chemical coating method that achieves similar reflective effects without requiring specialized equipment or complex manufacturing infrastructure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent modifies the chemical composition parameters of glass-ceramic coatings by incorporating specific effect pigments (aluminum oxide flakes, mica coated with metallic oxides) at controlled concentrations. By adjusting pigment type, size, and concentration, the coating achieves desired reflective properties while maintaining compatibility with standard ceramization processes, thereby simplifying manufacturing.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If enamels are deposited before ceramization, then high temperature resistance is improved, but only single deposit is possible and thickness is limited

Engineering Contradiction:
Improvehigh temperature resistanceVSAvoiddeposit layer complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent creates a composite coating system combining glass frit, effect pigments, and organic vehicle in a sol-gel formulation. This composite structure allows multiple functional components to work together: the glass frit provides high-temperature stability and bonding, while the effect pigments deliver reflective properties. The sol-gel matrix enables controlled delivery and uniform distribution of these components during a single ceramization cycle.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent performs preliminary mixing and formulation of the sol-gel composition before application, incorporating all necessary components (glass frit, effect pigments, solvents, additives) in precise proportions. This pre-prepared composition ensures uniform distribution of reflective particles and proper stoichiometry for ceramization reactions, enabling successful single-step deposition without requiring multiple sequential coating operations.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If paint is applied after ceramization, then multiple layers can be applied, but additional firing is required and temperature resistance is limited

Engineering Contradiction:
Improvelayer thicknessVSAvoidtemperature resistance
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent merges the coating application and ceramization processes into a single integrated operation. The sol-gel composition is applied to the green-glass substrate before the first ceramization cycle, so that the coating forms and matures simultaneously with the glass-ceramic body. This eliminates the need for separate post-ceramization painting and additional firing operations, achieving both multi-layer capability and high-temperature resistance in one process.

Inventive Principle:
Principle #5Merging (Combining)

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 nanometric layer enhances the reflective appearance of glass-ceramic plates, offering improved mechanical resistance, thermal stability, and compatibility with various heating types, while maintaining the desired optical and safety properties, and can be used with sensitive keys and induction coils, providing a cost-effective alternative to existing coatings.

Implementation Method 1

a nanometric layer based on a metallic material... which can be deposited by screen printing and withstands high temperatures... using a sol-gel composition

Methodology Applied
Scientific EffectSol-gel process: Sol

Implementation Method 2

whose specific chemical composition makes it possible to cause controlled crystallization by suitable heat treatments, called ceramization

Methodology Applied
Scientific EffectCeramization: Crystallisation

Implementation Method 3

a nanometric layer based on a metallic material with a refractive index higher than that of glass-ceramic... enhancing the reflective appearance

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

metallic materials with a refractive index higher than glass-ceramic such as aluminum oxide, titanium dioxide, or iron oxide

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2086899B1Manufacturing process for a glass-ceramic plate
Publication Date: 2021.12.08 EUROKERA SOC & NOM COLLECTIF

AI summary

The present invention relates to a glass-ceramic plate, intended for example to cover or accommodate at least one heating element, in particular intended to serve as a hob, said plate being at least partly coated with at least one nanoscale layer (<100 nm) based on a metallic material having a refractive index greater than that of the glass-ceramic. The invention also relates to the process for manufacturing the plate, to the screen-printable composition deposited on the plate, and to the cooking appliance comprising said plate.