Patent ID: 7958746

Claim:
A method for producing a light conversion material, the method comprising producing a glass ceramic for light conversion comprising the steps of providing a homogeneous starting glass comprising (on an oxide basis) 5-50% by weight of SiO 2 , 5-50% by weight of Al 2 O 3 and 10-80% by weight of at least one oxide selected from the group formed by Y 2 O 3 , Lu 2 O 3 , Sc 2 O 3 , Gd 2 O 3 , Yb 2 O 3 , Ce 2 O 3 , as well as 0.1-30% by weight of at least one oxide selected from the group formed by B 2 O 3 , Th 2 O 3 , and oxides of the lanthanoids, except Lu 2 O 3 , Gd 2 O 3 , Yb 2 O 3 , Ce 2 O 3 ; heating-up said starting glass for ceramization at a heating rate of at least 500 K/min to a first temperature T 1 in the range of 1000° C. to 1400° C.; holding said first temperature for a first period of time t 1 up to a maximum of 4 minutes; cooling said starting glass to a second temperature T 2 which is 50 to 200 K lower than said first temperature T 1 ; holding said second temperature T 2 for a second period of time t 2 up to a maximum of 1 to 20 minutes until crystallites are formed; and cooling down to room temperature.