leads 21 are electrically isolated from the patterned electrode 13 and are connected to the common electrode 14 the dimensions of the liquid crystal lens 1 are given below by way of example though they are not specifically limited to the values given here the glass substrates 11 and 12 each measure 10 millimeters square but the size can range from several millimeters to a dozen or so millimeters for the glass substrate 11 on which the patterned electrode 13 is formed however this dimension excludes the portion that covers the electrode leads 21 of the patterned electrode 13 the thickness of each of the glass substrates 11 and 12 is 300 u03bcm but thickness in the range of several hundred microns is allowable the thickness of the liquid crystal layer 14 is 23 u03bcm but can range from a dozen or so microns to several tens of microns the diameter of the lens area 18 is 2 4 mm but a diameter in the range of a few millimeters is allowable fig4 is a front view schematically showing the structure of the patterned electrode 13 as shown in fig4 the patterned electrode 13 has a pattern comprising a plurality of c shaped ring electrodes 24 which are formed in concentric circles of different radii around a circular shaped center electrode 23 an insulating space is provided between the center electrode 23 and the innermost ring electrode 24 as well as between each pair of adjacent ring electrodes 24 for reasons of illustration the number of ring electrodes 24 shown in fig4 is different from the actual number a plurality of leader electrodes 25 extend radially outward from the center electrode 23 and the plurality of ring electrodes 24 in such a manner as to be electrically isolated from.