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GB221415A - Improvements in bifocal lenses - Google Patents

Improvements in bifocal lenses

Info

Publication number
GB221415A
GB221415A GB172824A GB172824A GB221415A GB 221415 A GB221415 A GB 221415A GB 172824 A GB172824 A GB 172824A GB 172824 A GB172824 A GB 172824A GB 221415 A GB221415 A GB 221415A
Authority
GB
United Kingdom
Prior art keywords
glass
refractive index
blank
small
fusing
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
Application number
GB172824A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GEN OPTICAL Co
Original Assignee
GEN OPTICAL Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by GEN OPTICAL Co filed Critical GEN OPTICAL Co
Priority to GB172824A priority Critical patent/GB221415A/en
Publication of GB221415A publication Critical patent/GB221415A/en
Expired legal-status Critical Current

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

221,415. Pattison, E. W., (General Optical Co.). Jan. 22, 1924. Spectacle lenses.-A set of bifocal lens blanks, each of which is formed by fusing a small piece of glass having a relatively high refractive index to a major piece of glass of lower refractive index, is made up of a number of series according to the base curve of the semi-finished blank. Each series comprises a number of units having the small insert of different refractive indices. Corresponding units of the several series have therefore different base curves but the same refractive index of the small insert. The invention is described in connection with bifocal lens blanks formed by fusing a small piece of glass having a plane under surface to a major lens blank having a flat 3 formed on its surface to receive the glass 2. The exterior of the lens is then ground to the selected base curve. Numerical data and tables are given in the Specification. from which the optician may determine the curvature to which the back surface must be ground to fulfil the prescription, and the extent to which it may be necessary to modify the curvature of the finished surface of the blank.
GB172824A 1924-01-22 1924-01-22 Improvements in bifocal lenses Expired GB221415A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB172824A GB221415A (en) 1924-01-22 1924-01-22 Improvements in bifocal lenses

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB172824A GB221415A (en) 1924-01-22 1924-01-22 Improvements in bifocal lenses

Publications (1)

Publication Number Publication Date
GB221415A true GB221415A (en) 1924-09-11

Family

ID=9726956

Family Applications (1)

Application Number Title Priority Date Filing Date
GB172824A Expired GB221415A (en) 1924-01-22 1924-01-22 Improvements in bifocal lenses

Country Status (1)

Country Link
GB (1) GB221415A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150153589A1 (en) * 2013-11-29 2015-06-04 Carl Zeiss Vision International Gmbh Spectacle lens and method for making the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150153589A1 (en) * 2013-11-29 2015-06-04 Carl Zeiss Vision International Gmbh Spectacle lens and method for making the same
US10663764B2 (en) * 2013-11-29 2020-05-26 Carl Zeiss Vision International Gmbh Spectacle lens and method for making the same

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