Measurement of mechanical warpage in CR-39 lenses.
The warpage of CR-39 ophthalmic spherical lenses of a variety of powers and compressed in the radial direction is measured as a function of the applied tangential force. The lenses are cut with circular shape and then mounted on a frame specially designed to measure the tangential force by means of a calibrated coil spring. The measurements are performed with a high resolution micrometer at different points on the lens surfaces. The warpage of the two surfaces of each lens is calculated and then a quantitative value of surface power variation is given. From these data, vertex power and oblique astigmatism variation are shown. Departure of the surfaces from sphere as a function of the applied tangential force is analysed.
Alonso
J
J
Optics Department, Universidad Complutense de Madrid, School of Optics, Spain.
Peral
A
A
Sanz
J C
JC
Bernabeu
E
E
D005139:Eyeglasses / Q000592:standards*; D008962:Models, Theoretical; D055095:Optics and Photonics