PRODUCTION OF INFRARED OPTICAL MEMBER

摘要

PURPOSE:To obtain an inexpensive IR optical member having excellent power resistance to laser of high energy by pressurizing the IR optical member, for which a metallic halide is used, at the m.p. thereof or below. CONSTITUTION:TlBr-TlI mixed crystals (KRS-5) are used as a polycrystalline IR optical member and a lens 4 is made by a hot press method. A preform crystal cut out to a suitable size is put in a die 2 and is heated at a specified speed up to 200 deg.C. After said temp. is maintained for about 20-30min, the crystal is pressurized under 7-10 ton/cm<2>. The pressurizing surface of a pressurizing bar 1 and the surface of a receiving bar 3 are subjected to mirror polishing and are finished to 2,000Angstrom specular finish. The fine crystal in the optical lens is sized 10-20mum right after the pressurization and the crystal grows to about 250mum when held for about 30min. The grain boundaries of the crystal does not act as the boundary for optical reflection and scattering in the medium infrared region (2-20mum).