摘要 |
A retroreflective sheet structure (10) comprising a transparent layer (20) having a front light-receiving surface (30) and a rear retroreflecting surface (32). Light incident on the front surface (30) will pass through the layer (20), impinge on the rear retroreflective surface (32) and reflect back out through the front surface (30) in a predetermined direction. An identifying indicia (44) is chosen and then formed on the retroreflecting surface (32). This indicia (44) can be used for identification purposes, even years after an end product incorporating the reflective sheet structure (10) has been out in the field. |