Patterned adhesives for reflectors

Abstract

A reflector laminate, and backlights and displays incorporating such reflector laminates are disclosed. The reflector laminate includes a substrate and a reflector that are adhered together by a plurality of adhesive protrusions. The adhesive protrusions provide for a plurality of voids between the reflector and the substrate, so that a free reflector surface is adjacent to an air gap between the reflector and substrate. The reflector can include a multilayer interference reflector, and the presence of the air gap ensures high reflectivity for the laminate. The reflector can be adhered to a solid lightguide, a frame enclosing a portion of a backlight, a frame enclosing a hollow lightguide cavity, or an optical sheet positioned at the output surface of a backlight.

1 . A reflective laminate, comprising:
 a substrate having a first surface;   an optically thick adhesive layer in contact with the first surface of the substrate, the optically thick adhesive layer comprising a plurality of protrusions; and   an interference reflector having a second surface disposed facing the first surface of the substrate,   wherein a portion of the second surface is in contact with the protrusions.   
     
     
         2 . The reflective laminate of  claim 1 , wherein a void is defined between the second surface of the interference reflector, the protrusions, and the first surface of the substrate. 
     
     
         3 . The reflective laminate of  claim 1 , wherein the portion of the second surface of the interference reflector in contact with the protrusions comprises less than 10% of the second surface. 
     
     
         4 . The reflective laminate of  claim 1 , wherein the portion of the second surface of the interference reflector in contact with the protrusions comprises less than 5% of the second surface. 
     
     
         5 . The reflective laminate of  claim 1 , wherein the portion of the second surface of the interference reflector in contact with the protrusions comprises less than 1% of the second surface. 
     
     
         6 . The reflective laminate of  claim 1 , wherein a refractive index of the optically thick adhesive layer is less than a lowest refractive index of the interference reflector over a wavelength range of interest 
     
     
         7 . The reflective laminate of  claim 1 , wherein the interference reflector comprises a multilayer interference reflector. 
     
     
         8 . The reflective laminate of  claim 7 , wherein the multilayer interference reflector comprises a polymeric multilayer interference reflector. 
     
     
         9 . The reflective laminate of  claim 8 , wherein the polymeric multilayer interference reflector comprises a broadband mirror for visible light. 
     
     
         10 . The reflective laminate of  claim 1 , wherein the optically thick adhesive layer in contact with the first surface is a continuous layer. 
     
     
         11 . The reflective laminate of  claim 1 , wherein the optically thick adhesive layer in contact with the first surface is a discontinuous layer. 
     
     
         12 . The reflective laminate of  claim 11 , wherein the discontinuous layer is uniformly discontinuous. 
     
     
         13 . The reflective laminate of  claim 1 , wherein the optically thick adhesive layer in contact with the first surface comprises at least one microstructured surface. 
     
     
         14 . The reflective laminate of  claim 1 , wherein the protrusions comprise a plurality of ridges. 
     
     
         15 . The reflective laminate of  claim 1 , wherein the protrusions comprise a plurality of islands. 
     
     
         16 . The reflective laminate of  claim 1 , wherein the optically thick adhesive layer comprises a plurality of particles. 
     
     
         17 . The reflective laminate of  claim 1 , wherein the substrate comprises a diffuser. 
     
     
         18 . The reflective laminate of  claim 17 , wherein the interference reflector includes a third surface opposite the second surface, and further comprising:
 a second optically thick adhesive layer in contact with the third surface of the interference reflector; and   a second substrate having a fourth surface in contact with the second optically thick adhesive layer.   
     
     
         19 . The reflective laminate of  claim 18 , wherein the second optically thick adhesive layer comprises a second plurality of protrusions projecting from the fourth surface of the second substrate. 
     
     
         20 . The reflective laminate of  claim 18 , wherein the second optically thick adhesive layer comprises a second plurality of ridges. 
     
     
         21 . The reflective laminate of  claim 18 , wherein the second substrate comprises an optically transparent plate. 
     
     
         22 . The reflective laminate of  claim 18 , wherein the second substrate comprises a diffuser.