摘要 |
A METHOD OF FORMING AN OPTICALLY VARIABLE SECURITY DEVICE IS PROVIDED. IN THE METHOD, A PHOTONIC CRYSTAL MATERIAL IS PROVIDED AND A PROCESS IS PERFORMED UPON THE MATERIAL WHICH CAUSES DEFORMATION OF THE MATERIAL SO AS TO FORM A FIRST REGION (A) FOR WHICH INCIDENT LIGHT RECEIVED BY THE CRYSTAL MATERIAL IS SELECTIVELY REFLECTED OR TRANSMITTED TO GENERATE A FIRST OPTICALLY VARIABLE EFFECT, AND A SECOND REGION (B) FOR WHICH INCIDENT LIGHT RECEIVED GENERATES AN OPTICAL EFFECT, DIFFERENT FROM THE FIRST OPTICALLY VARIABLE EFFECT. CORRESPONDING DEVICES HAVING FIRST AND SECOND REGIONS ARE ALSO DISCLOSED. |