Glass-Ceramic Plate Composition for Hidden Elements and Clear Displays
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Solution Overview
Problem
Current lithium aluminosilicate glass-ceramic cooking plates face issues with high light transmission due to vanadium oxide, leading to visibility of heating elements when not in use, and contain toxic arsenic and antimony, causing darkening and toxicity concerns.
Innovation Solution
A glass-ceramic plate with optimized chemical composition and processing, featuring reduced vanadium oxide content, absence of arsenic and antimony, and controlled light transmission between 0.2 and 4% for wavelengths between 400 and 500 nm, utilizing metal sulfides and tin oxide for refining and reduction, and specific heat treatment cycles to achieve low thermal expansion and visibility of blue and green displays without distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high light transmission glass-ceramic is used, then displays are visible, but heating elements become visible when not in use
Solution Approach 1:
The patent applies different optical properties to different wavelength ranges: high transmission for blue-green light (450-550 nm) to ensure display visibility, while maintaining low transmission for red light and infrared to prevent heating element visibility. This selective wavelength-dependent optical filtering resolves the contradiction between display visibility and heating element concealment.
2Illumination intensity
If vanadium oxide is used for coloring, then red range wavelengths pass through, but the plate darkens over time due to continuous reduction
Solution Approach 1:
The patent changes the chemical composition parameters by replacing vanadium oxide with alternative coloring agents such as iron oxide, manganese oxide, or cobalt oxide that do not undergo continuous reduction. This compositional substitution maintains light transmission properties while eliminating the darkening issue, achieving both transmission and stability requirements.
3Ease of manufacture
If arsenic and antimony are used in glass-ceramic composition, then melting process is improved, but toxicity problems arise
Solution Approach 1:
The patent extracts and removes toxic arsenic and antimony from the glass-ceramic composition entirely, replacing them with non-toxic alternative materials such as iron oxide, manganese oxide, or organic melting agents. This extraction eliminates toxicity while maintaining or improving the melting process through the use of these safer alternative substances.
4Object-affected harmful factors
If low optical transmission is achieved, then heating elements are hidden, but display visibility is reduced
Solution Approach 1:
The patent implements wavelength-selective optical filtering where the glass-ceramic composition is designed to transmit blue-green light (450-550 nm) for display visibility while blocking red light and infrared radiation to conceal heating elements. This local quality approach applies different transmission properties to different parts of the spectrum, simultaneously achieving both concealment and visibility requirements.
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 solution provides controlled light transmission to hide heating elements when off, maintains display visibility without color distortion, and eliminates toxicity risks, ensuring safety and esthetic performance.
Implementation Method 1
Vanadium oxide is added to the batch materials of the mother glass before melting, and it gives, after ceramization, a very deep orange-brown color, linked to a reduction of the vanadium
Implementation Method 2
crystals of ⊕-quartz or β-spodumene structure (depending on the ceramization temperature), which have the distinctive feature of possessing negative coefficients of thermal expansion
Implementation Method 3
The glass-ceramic must also have good energy transmission properties, in particular for transmitting the infrared radiation produced by the heating elements
Data Source
AI summary
A glass-ceramic plate of lithium aluminosilicate free of arsenic and antimony, the optical transmission of which, for a thickness of 4 mm, is between 0.2 and 4% for at least one wavelength between 400 and 500 nm.