(19)
(11) EP 0 453 094 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
01.04.1992 Bulletin 1992/14

(43) Date of publication A2:
23.10.1991 Bulletin 1991/43

(21) Application number: 91302299.2

(22) Date of filing: 18.03.1991
(51) International Patent Classification (IPC)5: B24B 13/04, B24B 13/06
(84) Designated Contracting States:
AT BE CH DE DK ES FR GB IT LI NL SE

(30) Priority: 18.04.1990 US 510834

(71) Applicant: COBURN OPTICAL INDUSTRIES, INC.
Tulsa Oklahoma 74146 (US)

(72) Inventor:
  • Kulan, Stephen
    Fort Gibson, Oklahoma 74434 (US)

(74) Representative: Dunnett, Julie Elizabeth 
c/o Booth & Co. P.O. Box 8 Sovereign House South Parade
Leeds LS1 1HQ
Leeds LS1 1HQ (GB)


(56) References cited: : 
   
       


    (54) Lens grinding method and apparatus


    (57) The invention provides a method of generating a lens having desired base and cross curvatures by means of a circular cup shaped diamond tool (42), which is rotated about an axis and is swept repeatedly over a lens blank (68) to remove material so as to generate the required surface, the tool being positioned so as to produce the desired combination of base and cross curvatures on the blank, the method comprising positioning the diamond tool by means of a cross slide (24) and a base slide (22), both of which slides are free to move during the generation of the surface;
    sweeping the rotating tool over the lens blank and adjusting the cross slide and/or the base slide during the sweep thereby to vary the head angle of the tool during the sweep such that at any position in the sweep the instantaneous head angle is at a value whereby the desired cross curvature produced is constant over the sweep. The invention also relates to a lens generating machine.






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