GB257267A - Improvements in multifocal ophthalmic lenses - Google Patents
Improvements in multifocal ophthalmic lensesInfo
- Publication number
- GB257267A GB257267A GB20314/26A GB2031426A GB257267A GB 257267 A GB257267 A GB 257267A GB 20314/26 A GB20314/26 A GB 20314/26A GB 2031426 A GB2031426 A GB 2031426A GB 257267 A GB257267 A GB 257267A
- Authority
- GB
- United Kingdom
- Prior art keywords
- distance
- lens
- reading
- centre
- bifocal
- 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)
- Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
Abstract
257,267. American Optical Co., (Assignees of Hill, H. W., and Wheeler, R D.). Aug. 24, 1925, [Convention date]. Spectacle lenses.-Multifocal spectacle lenses having the distance and reading portions with a common optical axis and in which the line or division between the fields is free from a depression or raised shoulder are constructed by taking an ordinary one piece bifocal lens having separated optical axes and grinding thereon a second distance field at such an angle to the first distance field that it has the same optical axis. The various grinding operations are performed as follows :-A glass disc 21 sufficient for two lenses, moulded to the approximate shape of the lens and having on one side a distance portion 18 and a reading portion 20, is ground and polished on the bifocal side with a ring tool to produce the required distance portion 18, and the reading portion is then ground and polished to the radius 3. The disc is then divided into two blanks, each of which is made into a lens according to the invention by placing its bifocal side downwards on a table and centred. The table is then tilted to the angle which will make the distance portion coaxial with the reading portion, when the distance portion is reground. The lens is transferred to a'fresh lens holder, the centre of which is aligned with the centre of the table and the new distance portion 17 is ground and polished from the centre 6'. The finished side of the lens now comprises three surfaces, the new distance portion 17 co-axial with the reading portion 20, and an intermediate portion 18, which is bounded by a horizontal junction line 19 and a downwardly curved line where it joins the reading portion. The prescription side is subsequently ground from the centre 8 so that it is co-axial with the reading portion 20 and the new distance portion 17. If the prescription side is to be a toric surface the meridians are arranged to cross on the line 3, 1. Fig. 3, the common axis of the bifocal portions.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US257267XA | 1925-08-24 | 1925-08-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB257267A true GB257267A (en) | 1927-01-27 |
Family
ID=21827732
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB20314/26A Expired GB257267A (en) | 1925-08-24 | 1926-08-17 | Improvements in multifocal ophthalmic lenses |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB257267A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1135679B (en) * | 1956-04-13 | 1962-08-30 | Bozena Marie Phillips | One-piece bifocal spectacle lens and process for its manufacture |
| CN113732876A (en) * | 2021-09-11 | 2021-12-03 | 南京泰迅光学仪器有限公司 | Optical lens polishing device and polishing process |
-
1926
- 1926-08-17 GB GB20314/26A patent/GB257267A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1135679B (en) * | 1956-04-13 | 1962-08-30 | Bozena Marie Phillips | One-piece bifocal spectacle lens and process for its manufacture |
| CN113732876A (en) * | 2021-09-11 | 2021-12-03 | 南京泰迅光学仪器有限公司 | Optical lens polishing device and polishing process |
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