STATIC SEMI-RETRO-REFLECTIVE DISPLAYS
Conventional retro-reflective static traffic signage is primarily constructed of either heavy metal containing high refractive index glass beads embedded in a film or narrow viewing angle corner cubes. Disclosed herein are embodiments of static display signage having polymer-based circularly symmetric convex protrusions absent of heavy metals which reflect light in a semi-retro-reflective manner with wider viewing angles.
1 . A. A semi-retro-reflective display, comprising:
a transparent front sheet having a first surface and a second surface;
a plurality of protrusions facing away from the second surface of the transparent front sheet, the plurality of protrusions having a first refractive index;
a second medium abutting the plurality of protrusions, the second medium having a second refractive index; and
a rear substrate positioned below the second medium;
wherein the semi-retro-reflective display reflects light within an angular range of about ±30 degrees of the incident direction.
2 . The display of claim 1 , wherein the display defines a static semi-retro-reflective display.
3 . The display of claim 1 , wherein the protrusions are convex and substantially circularly symmetric.
4 . The display of claim 1 , wherein the protrusions have a diameter in the range of about 2-500 microns.
5 . The display of claim 1 , wherein the rear substrate further comprises an adhesive layer and a release layer.
6 . The display of claim 1 , further comprising an image layer.
7 . The display of claim 1 , wherein the second medium comprises a clear medium.
8 . The display of claim 1 , further comprising a support spanning from one of a plurality of protrusions to the rear substrate.
9 . The display of claim 1 , wherein the second medium is a gas and wherein at least one support spans from one of the plurality of protrusions to the rear substrate.
10 . The display of claim 1 , further comprising a light reflective coating to conform to the surface of the plurality of protrusions.
11 . The display of claim 1 , wherein the ratio of the first refractive index to the second refractive index is about 1.05 to 2.20.
12 . A semi-retro-reflective display, comprising:
a transparent front sheet having a first surface and a second surface;
a plurality of hemispherical protrusions facing away from the second surface of the transparent front sheet, the plurality of hemispherical protrusions having a first refractive index;
a second medium abutting the plurality of protrusions, the second medium having a second refractive index; and
a rear substrate positioned below the second medium;
wherein the hemispherical protrusions comprise a ratio of hemispherical height to the hemispherical width and a tangent angle (α).
13 . The display of claim 12 , wherein the display defines a static semi-retro-reflective display.
14 . The display of claim 12 , wherein the tangent angle (α) is in the range of about 60-80 degrees.
15 . The display of claim 12 , wherein the protrusions have a diameter in the range of about 2-500 microns.
16 . The display of claim 12 , further comprising a pitch distance
17 . The display of claim 12 , wherein the rear substrate further comprises an adhesive layer and a release layer.
18 . The display of claim 12 , further comprising an image layer.
19 . The display of claim 12 , wherein the second medium comprises a clear medium.
20 . The display of claim 12 , further comprising a support spanning from one of a plurality of protrusions to the rear substrate.
21 . The display of claim 12 , wherein the second medium is a gas and wherein at least one support spans from one of the plurality of protrusions to the rear substrate.
22 . The display of claim 12 , further comprising a light reflective coating to conform to the surface of the plurality of protrusions.
23 . The display of claim 12 , wherein the ratio of the first refractive index to the second refractive index is about 1.05 to 2.20.