Patent ID: 7220690

Claim:
An optical component comprising a substrate, said substrate comprising a glass ceramics which has a coefficient of thermal expansion CTE of from −0.5×10 −6 /K to +0.5×10 −6 /K in a temperature range of from 0 to 50° C., which is free of BaO, which is free of arsenic, and which has a composition, in % by weight based on oxide content, comprising: SiO 2 50–70 Al 2 O 3 17–32 P 2 O 5 3–12 Li 2 O 2.5–5 Na 2 O 0–2 K 2 O 0–2 MgO 0–2 CaO 0.1–4 SrO 0–2 ZnO 0–4 TiO 2 1.5–5 ZrO 2 0–2.5.