GB191210129A - Improvements in Bifocal Spectacle Lenses. - Google Patents
Improvements in Bifocal Spectacle Lenses.Info
- Publication number
- GB191210129A GB191210129A GB191210129DA GB191210129A GB 191210129 A GB191210129 A GB 191210129A GB 191210129D A GB191210129D A GB 191210129DA GB 191210129 A GB191210129 A GB 191210129A
- Authority
- GB
- United Kingdom
- Prior art keywords
- lens
- spherical
- wafer
- cylindrical
- toric
- 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)
- Eyeglasses (AREA)
Abstract
10,129. Jameson, A. April 29. Spectacle lenses.-In a bifocal, cylindrical, or toric spectacle lens for the correction of astigmatisms, an insertion D, Fig. 1, of dense glass is made at the astigmatic surface B, and a spherical depression C of the same size and shape is made at the spherical surface of the lens to reduce excess spherical power. This insertion or wafer has the same curvature as the external astigmatic curvature of the lens. The spherical depression C may be filled by glass having a lower index of refraction than that of the spectacle lens. The excess spherical power occasioned by the convex spherical curve A given to the wafer can be reduced or avoided by fusing or cementing it into a cylindrically curved depression, and by so choosing the index of refraction of the glass wafer that the added cylindrical effect may be divided between the outer and inner surface of the wafer. If the seating of the wafer is made cylindrical or toric, the lens is applicable to the correction of astigmatic presbyopes, provided that the cylindrical curvature of the seating be made at right-angles to the convex surface of the lens so that the two cylindrical powers may act together to produce a spherical power. A stopper or plug A, Fig. 2, of high refractive index may be inserted instead of the wafer and serves to increase the cylindricity of the reading portion of a deep periscopic toric lens, the concave surface A compensating for increase of spherical power at the toric surface B. In manufacture, the lens blank A, F, Fig. 3, may be made large enough to provide for making both lenses at one operation, the blank being cut across at the line D-D after the insertion E E has been made. A larger number of bifocal blanks may be made in the form of an annulas which may be cut up radially. For the modification of prismatic power and to correct errors in centration without introducing a spherical effect, a supplementary lens may be inserted in a manner similar to that already described. A compound lens may he inserted in stopper form, the lenses forming the compound stopper A B, Fig. 6, being decentred before being fused together.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB191210129T | 1912-04-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB191210129A true GB191210129A (en) | 1913-04-24 |
Family
ID=32368194
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB191210129D Expired GB191210129A (en) | 1912-04-29 | 1912-04-29 | Improvements in Bifocal Spectacle Lenses. |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB191210129A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2460648A1 (en) * | 2010-12-06 | 2012-06-06 | Opto Tech Optikmaschinen GmbH | Method for producing low-cost spectacle lenses |
WO2013072507A1 (en) * | 2011-11-16 | 2013-05-23 | Essilor International (Compagnie Générale d'Optique) | Method for providing an optical system of an ophthalmic spectacle lens and method for manufacturing an ophthalmic spectacle lens |
EP3301505A1 (en) * | 2016-09-29 | 2018-04-04 | Hoya Lens Thailand Ltd. | Spectacle lenses and methods for producing the same from a single semi finished lens |
-
1912
- 1912-04-29 GB GB191210129D patent/GB191210129A/en not_active Expired
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2460648A1 (en) * | 2010-12-06 | 2012-06-06 | Opto Tech Optikmaschinen GmbH | Method for producing low-cost spectacle lenses |
WO2013072507A1 (en) * | 2011-11-16 | 2013-05-23 | Essilor International (Compagnie Générale d'Optique) | Method for providing an optical system of an ophthalmic spectacle lens and method for manufacturing an ophthalmic spectacle lens |
CN103930821A (en) * | 2011-11-16 | 2014-07-16 | 埃西勒国际通用光学公司 | Method for providing an optical system of an ophthalmic spectacle lens and method for manufacturing an ophthalmic spectacle lens |
EP3301505A1 (en) * | 2016-09-29 | 2018-04-04 | Hoya Lens Thailand Ltd. | Spectacle lenses and methods for producing the same from a single semi finished lens |
WO2018062574A1 (en) * | 2016-09-29 | 2018-04-05 | Hoya Lens Thailand Ltd. | Spectacle lenses and methods for producing the same from a single semi finished lens |
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