| 摘要 |
<p>1,206,908. Protective films for lenses. LEYBOLD-HERAEUS-VERWALTUNG. June 26, 1969 [July 11, 1968] , No.32480/69. Heading G2J. [Also in Division C7] An optical component comprises a synthetic transparent thermoplastic base coated by vapour deposition with a glass comprising B 2 O 3 and Si0 2 , the coating being produced by melting particles of the tow components of size < 50 Á in vacuo and directing a jet of the vapour against the base, preferably at substantially 90 degrees to the surface thereof, the glass having from 0% to not more than 5% of any Na 2 O component and having its B 2 O 3 content adjusted to adapt the co-efficient of expansion thereof to that of the base material so that formation of hairline cracks is avoided when the component is subjected to temperature changes.</p> |
