GB422593A - Improvements in multi-focal or bifocal lenses - Google Patents
Improvements in multi-focal or bifocal lensesInfo
- Publication number
- GB422593A GB422593A GB8934A GB8934A GB422593A GB 422593 A GB422593 A GB 422593A GB 8934 A GB8934 A GB 8934A GB 8934 A GB8934 A GB 8934A GB 422593 A GB422593 A GB 422593A
- Authority
- GB
- United Kingdom
- Prior art keywords
- parts
- glass
- na2o
- sio2
- cao
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
- G02C7/00—Optical parts
- G02C7/02—Lenses; Lens systems ; Methods of designing lenses
- G02C7/06—Lenses; Lens systems ; Methods of designing lenses bifocal; multifocal ; progressive
Landscapes
- Health & Medical Sciences (AREA)
- Ophthalmology & Optometry (AREA)
- Physics & Mathematics (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Glass Compositions (AREA)
Abstract
422,593. Glass manufacture. BRITISH A. O. CO., Ltd., 39, Hatton Garden, London.- (American Optical Co. ; Southbridge, Massachusetts, U.S.A.) Jan. 1, 1934, No. 89. Drawings to Specification. [Class 56] [See also Group XX] In a fused bifocal &c. spectacle lens, the glass for the distance portion is composed of 71À6 parts SiO2, 11À6 parts Na2O, 2À5 parts K2O, 11.5 parts CaO, 1À0 part Sb2O5, 0À8 parts Na2SO4, and 1.0 part Al2O3, and that for the reading portion of 40À9 parts SiO2, 3À7 parts Na2O, 2À7 parts K2O, 29À1 parts BaO, 8À0 parts PbO, 3À9 parts CaO, 2À3 parts ZnO, 1.8 parts Sb2O3, 2À7 parts B2O3, 0.5 parts Fe2O3, and 0À4 parts Al2O3. The button to be fused into the major lens blank may be made in two parts, the upper part having the same optical properties as the major lens. This upper part may be made of the same glass as the blank, or of a different kind of glass with a slightly lower melting point and composed of 68À4 parts SiO2, 0À4 parts B2O3, 15À8 parts Na2O, 0À1 parts K2O, 4À4 parts CaO, 3À2 parts MgO, 1À8 parts PbO, 5À4 parts ZnO, and 0-6 parts Sb2O3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8934A GB422593A (en) | 1934-01-01 | 1934-01-01 | Improvements in multi-focal or bifocal lenses |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8934A GB422593A (en) | 1934-01-01 | 1934-01-01 | Improvements in multi-focal or bifocal lenses |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB422593A true GB422593A (en) | 1935-01-15 |
Family
ID=9698215
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8934A Expired GB422593A (en) | 1934-01-01 | 1934-01-01 | Improvements in multi-focal or bifocal lenses |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB422593A (en) |
-
1934
- 1934-01-01 GB GB8934A patent/GB422593A/en not_active Expired
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