Carl-zeiss-stiftung

Otto Trotscher

Meinrad Machler

Horst Stacklies

Erwin Wiedmann

The invention contemplates a method and apparatus for automatically performing digital measurement of vertex dioptric powers in the principal planes of toric spectacle lenses. A spectacle lens is transilluminated by a parallel-ray bundle of monochromatic light which, after passage through the spectacle lens, is limited by an annular stop in the immediate vicinity of the vertex of the spectacle lens. A beamsplitter divides the light which passes through the spectacle lens into two individual light beams. As a result, an elliptical figure is projected to two planes, in each of which is located at least one self-scanning diode line. Diode-line scanning develops intercepts of the projected elliptical figure, and from the positional locations of these intercepts (in relation to the local intercept of the optical axis) a computer performs a selected one of a plurality of evaluation procedures (a) to develop projected-figure reorientation or displacement as necessary to permit it then (b) to perform a desired measurement evaluation. Provision is made for automatic detection of whether a given spectacle lens is or is not within the currently set range of measurement capability and, if determined to be outside such range, the fact of such detection is operative to change optical elements of the apparatus for optimum measurement-range accommodation of the particular spectacle lens.

Digital focimeter and method

The invention contemplates a refractometer that images a test mark on the retina and is automatic in its determination of both refractive-power and astigmatism parameters, for the eye under examination. An imaging lens serves both (1) to project the test mark to the retina and (2) to convey that image for refocus external to the eye, to a scanner having the ability to digitally establish the eye's focal length. In the process of establishing the eye's focal length, the instrument automatically positions the imaging lens to best serve infinity viewing by the eye, and a prism then rotates the test mark while the scanner photoelectrically tracks the refocused image for the angles at which response is at a maximum, thus establishing astigmatism parameters. The instrument provides selective direct indication or print-out of the automatically determined parametric values.

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Aalen, Germany

Otto Trotscher