| 摘要 |
<p>A unitary sign panel including a transparent, preferably phosphorescent, plastic sheet (12) having a opposed forward and rearward planar surface (22, 24) and grooves (14) in the rearward planar surface (24) of the sheet to form outlines (16) of desired indicia viewable from the forward planar surface (22) of the sheet. Additional grooves (18) are provided in the rearward planar surface forming hatch patterns with the outlines of the selected indicia, which are also viewable from the forward planar surface of the sheet. The additional grooves preferably have a depth less than a depth of the grooves. The unitary sign panel is free of materials at the forward and rearward surfaces of the sheet such that light is transferable through the sheet in a direction perpendicular to the forward and rearward planar surfaces of the sheet. The sheet has a thickness sufficient for viewing through the sheet in the direction perpendicular to the forward and rearward planar surfaces of the sheet so that a viewer can see objects on the other side of the sign panel. The grooves and the additional grooves are preferably each V-shaped in cross-section. The grooves are preferably formed by engraving so that the sheet is substantially translucent at the grooves and is opaque at an apex of the V-shaped grooves. The sign panel utilized ambient light or can be provided with an artificial light source (50) disposed at an edge of the sheet.</p> |
