Retroreflector for use in touch screen applications and position sensing systems

摘要

A touch screen system and prismatic film includes a retroreflective substrate having a plurality of retroreflective elements having triangular cube corners. A metallized layer is disposed over at least a portion of the retroreflective elements. In one embodiment, the prismatic film includes two colored substrates mounted over the retroreflective elements. In another embodiment, a single substrate is mounted over the retroreflective elements. It is often desired that a color of the substrate(s) be chosen that is highly transparent in the infrared spectrum, but is also non-transparent in the visible light spectrum, giving the prismatic film a dark appearance. The prismatic film includes a plurality of retroreflective elements having triangular cube corners with a cant in a range between about 4 degrees in a face more parallel direction to 18 degrees in an edge more parallel direction and a cube depth between about 0.002 and 0.008 inches or with a cant of about 5.5 to 22 degrees in an edge more parallel direction and a cube depth between about 0.0005 and 0.004 inches, or with a cant of about 8 to 35 degrees in a face more parallel direction and a cube depth between 0.001 and 0.012 inches.

主权项

1. A prismatic film positionable along a periphery of at least a portion of the viewing area of a display, comprising:
an unpinned prismatic film having a retroreflective substrate, the retroreflective substrate having a plurality of triangular cube corner retroreflective elements formed in a first surface and a smooth second surface opposite the first surface, a first substrate disposed over at least a portion of the smooth second surface, a second substrate disposed between the first substrate and the smooth second surface, and a metallized layer disposed over at least a portion of the retroreflective substrate; wherein the retroreflective elements have a cant in a range of between about 4 degrees in a face more parallel direction to 18 degrees in an edge more parallel direction and a cube depth between about 0.002 and 0.008 inches, wherein base edges of the cube corner reflective elements are linear and in common plane, wherein each cube corner reflective elements forms an isosceles triangle cube shape with two of the base edges being approximately the same length, and wherein cube corner depth is determined by a constant (K) multiplied by a size of the viewing area of the display.