Visibly transparent, infrared radiation retroreflective articles

Patent metadata

Field	Value
Publication number	US-11726243-B2
Application number	US-201816957911-A
Country	US
Kind code	B2
Filing date	Dec 27, 2018
Priority date	Dec 31, 2017
Publication date	Aug 15, 2023
Grant date	Aug 15, 2023

Abstract

A retroreflective article including a retroreflective layer including a structured surface that is opposite a major surface, a pressure sensitive adhesive that contacts at least a portion of the structured surface to form an optically inactive area that does not substantially retroreflect incident light and at least one low refractive index layer forming an optically active area that retroreflects incident light, wherein the optically active area comprises about 25% or less of the structured surface.

First claim

We claim:

1. A retroreflective article comprising:
a. a retroreflective layer including a structured surface that is opposite a major surface;
b. a wavelength selective absorbing layer adjacent the major surface of the retroreflective layer,
c. a pressure sensitive adhesive that contacts at least a portion of the structured surface to form an optically inactive area that does not substantially retroreflect incident light; and
d. at least one low refractive index layer forming an optically active area that retroreflects incident light;
wherein the optically active area comprises about 25% or less of the structured surface, and
wherein the wavelength selective absorbing layer comprises one or both of a black dye and a black pigment and visible light retroreflected from the article is not perceptible to the human eye.

2. The retroreflective article of claim 1 wherein the optically active area defines a plurality of first regions and the optically inactive area defines one or more second regions.

3. The retroreflective article of claim 2 wherein the plurality of first regions comprise a barrier layer having sufficient structural integrity to substantially prevent flow of the pressure sensitive adhesive into the low refractive index layer.

4. The retroreflective article of claim 2 wherein the plurality of first regions form a pattern of discrete first regions.

5. The retroreflective article of claim 1 wherein the pressure sensitive adhesive is substantially clear.

6. The retroreflective article of claim 1 , wherein the wavelength selective absorbing layer has visible absorption at 400 nm-700 nm greater than about 30% and a near infrared transmittance at 830 nm-900 nm greater than about 30%.

7. The retroreflective article of claim 6 wherein the wavelength selective absorbing layer is adjacent only the first regions.

8. The retroreflective article of claim 1 wherein the structured surface comprises cube corner elements.

9. The retroreflective article of claim 1 wherein the article is flexible or conformable.

10. The retroreflective article of claim 1 wherein the optically active area comprises about 20% or less of the structured surface.

11. The retroreflective article of claim 10 wherein the optically active area comprises about 10% or less of the structured surface.

12. A LiDAR system comprising a LiDAR source, an IR sensor and the retroreflective article of claim 1 .

13. An automotive component comprising a pigmented fascia, painted fascia or window, and the retroreflective article of claim 1 .

Assignees

• 3M Innovative Properties Company

Inventors

• Lamb David J
• Du Guanglei
• Kopp Scotty A
• Patel Suman K
• Wheatley John A

Classifications

• G02B5/20 Primary

  Filters (polarising elements G02B5/30) · CPC title

• G01S7/481

  Constructional features, e.g. arrangements of optical elements · CPC title

• G01S17/02

  Systems using the reflection of electromagnetic waves other than radio waves (G01S17/66 takes precedence) · CPC title

• G02B5/124 Primary

  plural reflecting elements forming part of a unitary plate or sheet · CPC title

• G02B5/208

  for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation · CPC title