Transparent coloured lithium aluminium silicate glass ceramic and process for production and use of the glass ceramic
AssigneeSchott AG
InventorsFriedrich SIEBERS, Oliver HOCHREIN
Life of this patent
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Abstract
A transparent coloured lithium aluminium silicate glass ceramic and method of producing are provided. The glass ceramic has a brightness Y of 0.1% to 80% at thickness 4 mm. The glass ceramic has a D65 standard illuminant light, after passing through the glass ceramic with thickness 4 mm, with a colour locus in a white region W1 determined by coordinates in a chromaticity diagram CIExyY-2°: White region W1 x y 0.27 0.21 0.22 0.25 0.32 0.37 0.45 0.45 0.47 0.34 0.36 0.29.
Claims18
A transparent coloured lithium aluminium silicate glass ceramic, comprising:
- a brightness Y of 0.1% to 80% at thickness 4 mm;
- and
- a D65 standard illuminant light has a colour locus in the white region W1 determined by coordinates in a chromaticity diagram CIExyY-2°:
- White region W1
- x
- Y
- 0.27
- 0.21
- 0.22
- 0.25
- 0.32
- 0.37
- 0.45
- 0.45
- 0.47
- 0.34
- 0.36
- 0.29.
A process for producing an article from a transparent coloured lithium aluminium silicate glass ceramic, comprising:
- providing a batch recipe for industrial raw materials containing 20% to 80% by weight of shards;
- melting the batch recipe and refining at temperatures of at least 1600° C. to form a glass melt;
- establishing a reduced state in the glass melt in which no crystals are formed;
- cooling the glass melt and shaping at temperatures close to a working temperature to produce the article of a desired shape of crystallizable glass;
- cooling the article in an annealing oven to room temperature so as to remove unwanted stresses;
- increasing a temperature of the crystallizable glass to the temperature region of about 680° C. within 3 to 60 minutes;
- increasing the temperature of the crystallizable glass within the temperature range of nucleation of 680 to 800° C. over a period of about 10 to 100 minutes to produce crystallization nuclei in the crystallizable glass;
- increasing the temperature of the crystallizable glass containing the crystallization nuclei to the temperature range of high crystal growth rate of 850 to 980° C. within a period of 5 to 80 minutes;
- holding within the temperature range of high crystal growth rate for up to 60 minutes;
- and
- cooling the glass ceramic obtained to room temperature within less than 150 minutes, with a total duration for the ceramization of the glass of less than 300 minutes.
Dependencies are inferred from the claim text.