GB424321A - Multifocal ophthalmic lenses and method of making the same - Google Patents

Multifocal ophthalmic lenses and method of making the same

Info

Publication number
GB424321A
GB424321A GB17656/34A GB1765634A GB424321A GB 424321 A GB424321 A GB 424321A GB 17656/34 A GB17656/34 A GB 17656/34A GB 1765634 A GB1765634 A GB 1765634A GB 424321 A GB424321 A GB 424321A
Authority
GB
United Kingdom
Prior art keywords
minor
reading
lenticular surface
lens
major
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
GB17656/34A
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of GB424321A publication Critical patent/GB424321A/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

Abstract

424,321. Spectacle lenses. HUBBELL, D. D., 82, North High Street, Columbus, Ohio, U.S.A. June 14, 1934, No. 17656. Convention date, June 14, 1933. [Class 97 (i)] A one-piece ophthalmic lens blank has on one side a major lenticular surface, e.g. a distance portion, and a minor non-circular lenticular surface, e.g. a reading portion, the minor lenticular surface projecting above the major lenticular surface and the axis of generation of one surface being inclined with respect to that of the other. A blank is first moulded to have two surfaces of different curvatures on one side, the minor surface being raised and having an external contour of more than a half circle and less than a full circle as shown at 1, Fig. 2. The blank is mounted on a turntable and a grinding tool applied to the surface 2, i.e. the distance vision portion of the lens, the tool being moved to grind the top edge of the minor portion 1 as the table rotates. A protective collar of glass or hard wax may be fitted snugly and cemented round the minor portion 1 and with the axis of generation tilted from its former position the reading segment is ground, the remaining parts of the collar being then removed. A shoulder shaped like a double wedge thickest at the centre and pointed at the ends is present at the flat top of the reading segment. The size of this shoulder is reduced by extending the reading segment 1 above the horizontal diameter line 3-3. Fig. 7 shows a finished lens in which the size of the shoulder 8 has been further reduced by submerging the lower part of the reading segment giving rise to small shoulders at 10, 11. The shoulders 8, 10, 11, may be chamfered. The upper edge of the reading portion may be a straight line or flat arc joined to the circular edge by small arcs. The optical centre of the reading segment may be arranged at or near the dividing line in order to minimize jumping of the image as the vision passes over the dividing line. Fig. 17 shows a lens in which the minor lenticular surface 29 constitutes the distance portion and the major lenticular surface 27 the reading portion.
GB17656/34A 1933-06-14 1934-06-14 Multifocal ophthalmic lenses and method of making the same Expired GB424321A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US424321XA 1933-06-14 1933-06-14

Publications (1)

Publication Number Publication Date
GB424321A true GB424321A (en) 1935-02-19

Family

ID=21921908

Family Applications (1)

Application Number Title Priority Date Filing Date
GB17656/34A Expired GB424321A (en) 1933-06-14 1934-06-14 Multifocal ophthalmic lenses and method of making the same

Country Status (1)

Country Link
GB (1) GB424321A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013104887A2 (en) 2012-01-11 2013-07-18 Hesco Bastion Limited Gabion deployment platform

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013104887A2 (en) 2012-01-11 2013-07-18 Hesco Bastion Limited Gabion deployment platform

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