System having a telecommunications element being concealed by a reflective structure comprising a polymer optical multilayer film

Patent metadata

Field	Value
Publication number	US-10720698-B2
Application number	US-201515525364-A
Country	US
Kind code	B2
Filing date	Dec 9, 2015
Priority date	Dec 9, 2014
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

A system having a concealed communications element like a telecommunication antenna is described. More specifically, The system has a communications element that is concealed by a highly reflective multilayer polymer optical film 200 . The first element of the multilayer polymer optical film is a core layer 202 that is made up of a multilayer optical stack. The multilayer optical stack of core layer 202 includes two alternating polymeric layers. The multilayer polymer optical film may optionally also include a protective layer 204 (for example, a hardcoat or an over laminate) that is positioned between the viewer and the core layer. The protective layer 204 may include one or more UV absorbers to aid in durability of the multilayer polymer optical film against UV-degradation. Multilayer polymer optical film 200 may optionally also include an adhesive layer 208 that is positioned between the core layer 202 and a surface onto which the multilayer polymer optical film is to be adhered.

First claim

What is claimed is:

1. A method of concealing an outdoor communications element, wherein the communications element positioned on one of the top of a building, the side of a building, a light pole, a telephone pole, a ceiling, and an interior wall comprises at least one of an antenna, a radio, and a small cell antenna, comprising at least partially surrounding the outdoor communications element with a reflective non-metallic multilayer optical film, such that the multilayer optical film conceals the outdoor communications element from viewers, and reflects ambient light towards viewers, the multilayer optical film comprising a core layer that comprises a multilayer optical stack comprising two alternating polymeric layers, and a UV stable protective layer.

2. The method of claim 1 , wherein the first polymeric layer comprises a birefringent material and the second polymeric layer comprises one of an acrylic-based polymer blended with a fluoropolymer or an acrylic-containing copolymer.

3. The method of claim 1 , wherein a specular reflectivity of light at 660 nm as reflected by the multilayer polymer optical film decreases less than 10% from its first exposure until after 12,750 hours of ISO 4892-2:2013 Cycle 4 weathering procedure.

4. The method of claim 1 , wherein a b* yellowness index of the multilayer polymer optical film changes by less than 3 from its first exposure until after 12,750 hours of ISO 4892-2:2013 Cycle 4 weathering procedure.

5. The method of claim 1 , wherein an average reflectance along each stretch direction of the multilayer polymer optical film at normal incidence over the wavelength range from 380-1500 nm is greater than 50 percent and less than 90 percent.

6. The method of claim 1 , further comprising a textured layer formed on top of the multilayer polymer optical film.

7. The method of claim 1 , wherein the multilayer optical film comprises multiple gaps, wherein a gap pattern comprises a closed area to open area ratio of about 70:30 or less.

8. The method of claim 1 , wherein the multilayer polymer optical film is formed into a non-planar three-dimensional shape.

9. The method of claim 1 , wherein the multilayer polymer optical film has a specular reflectivity in the visible spectrum of greater than 80%.

Assignees

• 3M Innovative Properties Co

Inventors

• Larson Donald K
• Schardt Craig R
• King Stephen C
• Treadwell Daniel J
• Yemelong Constand E
• Carls Joseph C
• Kipke Cary A

Classifications

• G02B5/08 Primary

  Mirrors {(vehicle mirrors involving special optical features B60R1/08)} · CPC title

• B32B2307/418

  Refractive · CPC title

• B32B2571/00

  Protective equipment · CPC title

• B32B2250/246

  All polymers belonging to those covered by groups B32B27/32 and B32B27/30 · CPC title

• B32B27/322

  comprising halogenated polyolefins, e.g. PTFE · CPC title