Digital gauge for measuring sagittal depth and thickness of lens, and

Abstract

A digital gauge for measuring the sagittal depth and thickness of a lens comprises an encoder for deriving electrical signals corresponding to the saggital depth and thickness of the lens, a first digital circuit responsive to the electrical signals corresponding to the sagittal depth of the lens for producing a first digital output representing the sagittal depth, a second digital circuit responsive to the electrical signals corresponding to the thickness of the lens for producing a second digital output representing the thickness, and a display unit responsive to the first and second digital outputs for displaying the sagittal depth and thickness, respectively, of the lens. A first embodiment employs dual encoders and associated dual moveable plungers, while a second embodiment employs a single encoder and associated moveable plunger, together with a fixed stop in alignment with the plunger. According to the related methods, various sequences of a minimum number of steps are executed to manipulate the lens so as to obtain numerical display of the sagittal depth and thickness of the lens. Other features of the digital gauge include provision for retaining one or both displays of sagittal depth and thickness, and provision for calibration of the circuitry which measures the sagittal depth and thickness, respectively, of the lens. The related system automatically computes the sagittal depth and thickness by obtaining measurement data from the digital gauge on request, or by manual input of the measurement data by the operator.