Optical glass with varying refraction index

Details Optical glass with varying refraction index Optical glass with varying refraction index

1997-10-28

1999-09-28

Bell, Mark L.

Compositions: ceramic

Ceramic compositions

Glass compositions, compositions containing glass other than...

501 66, 501 69, 501 72, 501 75, 501 77, 501900, 65 3013, C03C 3064, C03C 3072, C03C 3085, C03C 3091

Patent

active

059588101

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL AREA

The invention relates to an optical glass or lens with a refractive index that varies as a function of at least one coordinate and is produced from a starting material with a constant refractive index by ion exchange.


PRIOR ART

Optical glasses with varying refractive indexes according to the preamble of the secondary claims have bene known for a long time. In the known optical glasses, the variation in refractive index is too narrow for many applications such as spectacle lenses. Moreover, known materials produced by ion exchange have comparatively low stability in aggressive media such as "sea air." This means that aggressive media can cause the lens to cloud and/or lead to an undesired variation in refractive index.


EXPLANATION OF INVENTION

A goal of the invention is to further the development of optical glasses in such a manner that, for ophthalmologic applications for example, they have sufficient stability with a variation in refractive index of at least 0.07.
One method of achieving this goal according to the invention is provided in the secondary claims. Further embodiments of the invention are subjects of the dependent claims.
According to one aspect of the present invention the optical glass is produced from a starting material containing the following substances


______________________________________ SiO.sub.2 56 wt. % .+-. 5 wt. % Na.sub.2 O 23.5 wt. % .+-. 2 wt. % TiO.sub.2 17 wt. % .+-. 2 wt. % SnO.sub.2 4.5 wt. % .+-. 2.5 wt. % Sb.sub.2 O.sub.3 0.01 . . . 0.7 wt. % NaCl 0.05 . . . 1 wt. % ______________________________________
According to another aspect of the invention alternative material is provided.
With this material, the starting material contains the following substances:


______________________________________ SiO.sub.2 45 wt. % .+-. 2.5 wt. % Al.sub.2 O.sub.3 30 wt. % .+-. 3 wt. % Na.sub.2 O 16.5 wt. % .+-. 1.5 wt. % B.sub.2 O.sub.3 7.5 wt. % .+-. 1.5 wt. % Li.sub.2 O 1.0 wt. % .+-. 0.2 wt. % ______________________________________ silver melt.
According to another aspect of the invention third starting material is disclosed. With this material, the starting material consists of the following substances:


______________________________________ SiO.sub.2 40 wt. % .+-. 5 wt. % Al.sub.2 O.sub.3 30 wt. % .+-. 5 wt. % Na.sub.2 O 14.5 wt. % .+-. 5 wt. % B.sub.2 O.sub.3 12 wt. % .+-. 2.5 wt. % Li.sub.2 O 3 wt. % .+-. 1.5 wt. % ______________________________________
Another starting material contemplated by the present invention includes the following composition:


______________________________________ SiO.sub.2 39 wt. % .+-. 5 wt. % Al.sub.2 O.sub.3 30 wt. % .+-. 5 wt. % Na.sub.2 O 15 wt. % .+-. 2 wt. % B.sub.2 O.sub.3 12 wt. % .+-. 2.5 wt. % Li.sub.2 O 2 wt. % .+-. 0.8 wt. % BaO 2 wt. % .+-. 0.8 wt. % ______________________________________
An additional alternative for the optical glass is given by the starting material containing the following substances:


______________________________________ SiO.sub.2 37 wt. % .+-. 3 wt. % Al.sub.2 O.sub.3 28.5 wt. % .+-. 3 wt. % Na.sub.2 O 15 wt. % .+-. 2 wt. % B.sub.2 O.sub.3 11.5 wt. % .+-. 2 wt. % Li.sub.2 O 2 wt. % .+-. 0.5 wt. % PbO 6 wt. % .+-. 1.5 wt. % ______________________________________
Although percentages and specific tolerance ranges are listed above, it is understood that changes can be made.
Further embodiments are the subject of other claims, including the following:
With the materials according to the invention, not only can the variation in the refractive index amount to approximately 0.1, but the refractive index can also can vary over a range of approximately 10 mm from the peripheries.
The present invention is further directed to methods for producing the optical glasses according to the invention are given:
one aspect of the invention is a method for varying the refractive index, in which ion exchange of the starting material takes place in a salt melt, is characterized in that, with a starting material containing SiO.sub.2, 56 wt. % (.+-.5 wt. %); Na.sub.2 O,

REFERENCES:
patent: 3873408 (1975-03-01), Hensler
patent: 4038090 (1977-07-01), Gliemeroth
patent: 4076544 (1978-02-01), Kerko et al.
patent: 4405672 (1983-09-01), Araujo et al.
patent: 4576104 (1986-03-01), Wu
patent: 4756733 (1988-07-01), Houde-Walter et al.
patent: 4812423 (1989-03-01), Kodama et al.
patent: 5007948 (1991-04-01), Araujo
patent: 5145757 (1992-09-01), Smoot et al.
patent: 5674790 (1997-10-01), Araujo
French, William G., et al., Refractive Index Changes Produced in Glass by Ion Exchange, Ceramic Bulletin, vol. 49, No. 11 (1970), pp. 974-977. No Month .
Livshits, V. Ya., Elastic and Optical Properties of Alkali Titanium Tin Silicate . . . , Glass Physics and Chemistry, Jul./Aug. 1994, vol. 20, No. 4, New York. pp. 340-344.
Maksimov, V.M., Aplanatic Radial Gradient-Index Lenses Produced . . . , Glass Physics and Chemistry, Jan./Feb., vol. 20, No. 1, New York, pp. 52-58.
Fujii, Kiyosumi, Selective Adsorption of Lithium Ions From Molten Salt . . . , Journal of the Ceramic Society of Japan, 102 (1994) Oct., No. 10, Tokyo, Japan, pp. 900-904.
Houde-Walter, Susan N., et al., Delta-n Control in Grin Glass by . . . , Applied Optics, 25(1986) Oct. 1, No. 19, New York, pp. 3373-3378.

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