IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0281637
(1988-12-09)
|
우선권정보 |
FR-0010269 (1988-07-29) |
발명자
/ 주소 |
- Prassas Michel (Avon FRX)
|
출원인 / 주소 |
- Corning Incorporated (Corning NY 02)
|
인용정보 |
피인용 횟수 :
16 인용 특허 :
4 |
초록
▼
The present invention is related to transparent, fast darkening and fading photochromic glasses. The glasses contain SiO2, B2O3, Al2O3, ZrO2, Li2O, Na2O, K2O, MgO, CaO, SrO, BaO, ZnO, La2O3, Nb2O5, TiO2 as base glass components, Ag, Br, Cl, CuO as photochromic elements, with, optionally, Sb2O3, As2O
The present invention is related to transparent, fast darkening and fading photochromic glasses. The glasses contain SiO2, B2O3, Al2O3, ZrO2, Li2O, Na2O, K2O, MgO, CaO, SrO, BaO, ZnO, La2O3, Nb2O5, TiO2 as base glass components, Ag, Br, Cl, CuO as photochromic elements, with, optionally, Sb2O3, As2O3, and SnO2 as colorants to impart a brown color at darkening. The glasses have a refractive index greater than 1.585, an Abbe number greater than 42, and a density lower than about 2.80 g/cm3.
대표청구항
▼
A photochromic glass having a refractive index greater than 1.585, an Abbe number greater than 42, a density lower than 2.80 g/cm3, a liquidus viscosity of at least 200 poises, and, at a thickness of 2 mm, exhibits photochromic properties of (I) a luminous transmission in the unexposed state greater
A photochromic glass having a refractive index greater than 1.585, an Abbe number greater than 42, a density lower than 2.80 g/cm3, a liquidus viscosity of at least 200 poises, and, at a thickness of 2 mm, exhibits photochromic properties of (I) a luminous transmission in the unexposed state greater than 84%, (II) a luminous transmission in the darkened state after 15 minutes\exposure to actinic radiation at a temperature between 0°-25°C. of less than 40%, (III) a fading rate at 20°-25°C. such that five minutes after removal from the actinic radiation the glass has a luminous transmission of at least 55%, and (IV) a difference between the luminous transmissions of the darkened state over the temperature range 25°-40°C. of less than 23 points of transmission, said glass consisting essentially of: (a) a base glass composition consisting essentially, expressed in terms of weight percent on the oxide basis, of ________________________________ -SiO2 33-50 MgO 0-5 B2O3 15-25 CaO 0-5 SiO2 +B2O3 58-66 SrO 0-10 Al2O3 2-9 BaO 0-10 ZrO2 1-5 ZnO 0-5 Al2O3 +ZrO2 4-10 MgO +CaO + 1-15 (XO) SrO +BaO + ZnO Li2O 1.5-6 X2O +XO 10-24 Na2O 0-4 La2O3 0-5 K2O 2-9 Nb2O5 8-16 Li2O +Na2O + 7-16 (X2O) TiO2 2-8 K2O Li2O/X2O 0.20-0.50 ZrO2 +TiO2 + 14-23 Nb2O5 +La2O3 ________________________________ and (b) photochromic elements consisting essentially, as analyzed in weight percent, of ________________________________ Ag 0.130-0.280 Br 0.130-0.220 Ag +Br > 0.270 Cl 0.170-0.360 CuO 0.0070-0.0350. ________________________________
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