| 摘要 |
<p>PCT No. PCT/US96/12916 Sec. 371 Date Feb. 13, 1998 Sec. 102(e) Date Feb. 13, 1998 PCT Filed Aug. 7, 1996 PCT Pub. No. WO97/09278 PCT Pub. Date Mar. 13, 1997The present invention relates to a method of making a rectangular bar have a gradient composition. In optical or ophthalmic applications, the gradient of composition ensures formation of a corresponding gradient of optical property, such as refractive index or optical density. The glass material is manufactured using a device containing several reservoirs, all designed to contain glass in the fluid state. According to the invention, the composition of the glass varies from one reservoir to the other so that the refractive indices, for example, of the three compositions are different, with an incremental progression. The fluid glass is deposited one composition on top of the next and then heated, creating a certain degree of interdiffusion between the layers. The glass is then heat-treated to create the desired property profile.</p> |
