Carl-Zeiss-Stiftung

Hans Lahres

Gerhard Kelch

Helmut Wietschorke

Gerhard Furter

Hubert Bammert

Konrad Saur

Egon Mosch

A multifocal spectacle lens has two optically effective surfaces with powers in the far reference point from -4.0 dpt to +4.0 dpt in the stronger principal section. The spectacle lens has cylinders from 0.0 dpt to 4.0 dpt and an addition of 1.00 dpt to 3.00 dpt. The multifocal area is at least aspherical and can be differentiated continuously at least twice and is not axial symmetrical. The multifocal surface includes a far vision zone, a near vision zone and a progression zone lying between the near and far vision zones. The lens body is configured to incorporate a plurality of features within an elliptical region on the surface of the lens body extending 50 mm measured horizontally and 40 mm measured vertically from the measurement point. These features are all satisfied together within the elliptical region. One of the features is that the near-reference point is at most 21 mm perpendicularly below the far-reference point and displaced by about 2.5 mm toward the edge. Also, a principal viewing line interconnects the far-vision zone and the near-vision zone and the principal viewing line defines a curve swung toward the edge more or less in dependence upon the dioptric power of the far-vision zone and the addition. A predetermined region is formed in the progression zone on both sides of the principal viewing line wherein astigmatic deviation is less than 0.75 dpt.

Multifocal spectacle lens

The invention is directed to a spectacle lens having a multifocal surface and a prescription surface. The prescription surface is a general aspheric surface without point and axis symmetry. Of the individual use conditions, at least the dioptric power is considered within an area when determining the geometry of the prescription surface. The prescription surface is provided exclusively for generating the dioptric power in the reference points and additionally for eliminating the increase of imaging errors.

Spectacle lens

The invention is directed to a multifocal surface for a multifocal lens which, for a short progression zone between a far-vision zone and near-vision zone, has a large usable width of this zone and the near-vision zone, and for which the maximum value, which the surface astigmatism reaches on the multifocal surface, is less than the 1.1 multiple of the surface increment. Such a multifocal surface is obtained when this surface is configured as twice continuously differentiable and satisfies a combination of six features which relate to the distribution of surface astigmatism and mean surface refractive power across the multifocal surface.

Multifocal surface for a multifocal spectacle lens

In eyeglass lenses which have a center thickness greater than the edge thickness in at least one cross section and different dioptric powers in different sections, round-blanks lead to ground eyeglass lenses which are of relatively high weight. The weight of such an eyeglass lens, and thus its center and edge thickness, is reduced if the blank is imparted a substantially elliptical edge curve. In order to reduce cost and expense, the dioptric range of the series of eyeglass lenses is divided into a predetermined number of ranges and a given type of edge curve is associated with each range. Within each range there are a number of centrally similar edge curves of different height and width for such type of edge curve. All edge curves are so selected that the eyeglass lens blanks provided with them have an edge thickness over the elliptical portion of their periphery which varies by less than 1.5 mm. An easily operated device is provided in order to select the optimal blank for mounting in an eyeglass frame.

Blank for eyeglass lenses having ellipse-like edge curves and means and

Eyeglass lenses for persons suffering from severe ametropia. The lenses have a convexly shaped object-side front surface (4) and an eye-side rear surface (3) which is aspherically corrected in the central region (6) which comprises at least the main field of view. From this region the rear surface passes into a region in which its meridional inclination approaches the inclination of the front surface. The entire rear surface of the lens is continuously differentiable twice. Such a lens has an appearance which is fully satisfactory esthetically and makes it possible to keep the overall magnification of the system consisting of the eye and the eyeglass lens closer to 1 than in the case of previously known lenses. Aberrations are optimally corrected within a sufficiently large region, and no disturbing discontinuities in the fields of view occur.

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Aalen-Wasseralfingen, Germany

Hans Lahres