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Abstract

An improved lensmeter comprising a conventional optical system and a novel displaying system. The displaying system includes a linear encoder producing two sets of pulse signals equivalent to the distance and direction of linear movement of the target and circuitry for converting the two sets of pulse signals to a dioptral number of digits, and displaying it. The dioptral number has a plus or minus sign and precision of 0.125 or 0.06 diopters. The displaying system also includes two circuits for displaying at the same time 'the power of the sphere' (S) and 'the power of the cylinder' (C) of an astigmatic lens respectively as a dioptral number of digits, a rotary encoder and circuitry for displaying 'the direction of axis of the cylinder' (Ax) as an angular degree of digits, a (C) sign transposing circuit, and a cylinder form transposing circuit.

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First Claim