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AssigneeOptoTech Optikmaschinen GmbH
InventorRoland MANDLER
Estimating the term…
The invention relates to a method for the production of spectacle lenses from raw lenses prefabricated in a non-cutting manner. The raw lenses have a front side that is not to be reworked and an opposing back side to be reworked with a CNC machine, which sides have at least one optical focal point in common. In order to rework the back side a prescription surface is calculated on the basis of a prescription describing a visual error and of the geometry of the front side. This surface forms a prescription lens in common with the front side, the focal points of which lens correct the visual error. The front side is shaped in such a manner that it is a convex and rotationally symmetrical first freeform surface. This freeform surface is composed in a rotationally symmetrical manner about a middle axis by at least two spherical sections with different radii, whereby the spherical sections border each other tangentially. Furthermore, the spectacle lens has an optical center through which an eyeglass wearer looks when looking straight ahead (zero view direction). The spectacle lens is manufactured in such a manner by an adaptation of the raw lens to an eyeglasses frame that the middle axis of the raw lens lies outside of the optical center of the spectacle lens.
A method for producing spectacle lenses (1) from raw lenses (10) prefabricated in a non-cutting manner and that have a central axis (M) standing vertically on the raw lens (10), whereby the raw lenses (10) comprise a convex front side (11) that is formed in a rotationally symmetrical manner about the central axis (M) and is not to be reworked and comprises an opposing back side (12) that is to be reworked with a CNC machine, which sides have in common at least one optical focal point, whereby in order to rework the back side (12) a prescription surface (13) is calculated in such a manner on the basis of a prescription of prescription holder that describes a visual error that the worked back side (12) forms together with the front side (11) a prescription lens (14) whose focal points correct the visual error of the prescription holder, whereby a spectacle glass (1) with an optical center (Z) through which an eyeglasses wearer looks when looking straight ahead (zero view direction) is manufactured from the prescription lens (14) by adaptation to an eyeglass frame (2), characterized in that the front side (11) of the raw lens (10) is formed as a first freeform surface (21) that is composed from the middle axis (M) outward by at least two spherical sections with different radii (RBH1-RBHn), that the spherical sections tangentially border on one another in a sphere transition (40), and whereby the prescription lens (14) is adapted in such a manner to the eyeglass frame (2) that the middle axis (M) of the raw lens (10) lies outside of the optical center (Z) of the spectacle lens (1).
Dependencies are inferred from the claim text.