Optically active materials and articles and systems in which they may be used

• US 10,417,534 B2
• Filed: 02/21/2017
• Issued: 09/17/2019
• Est. Priority Date: 12/15/2008
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Smithson, Robert L. W., Biernath, Rolf W.
• Primary Examiner(s): Powers, Laura C
• Application Number:
  US15/437,880
• Publication Number:
  US 20170161593A1
• Time in Patent Office: 938 Days
• CPC Class Codes: B60R 13/10 Registration, licensing, or like devices
• CPC Class Codes: G02B 5/0816 Multilayer mirrors, i.e. having two or more reflecting layers G02B5/0883, G02B5/0891 take precedence
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: G02B 5/128 transparent spheres being embedded in matrix
• CPC Class Codes: G02B 5/136 plural reflecting elements forming part of a unitary body G02B5/124 takes precedence
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: G02B 5/26 Reflecting filters G02B5/28 takes precedence
• CPC Class Codes: G06V 10/143 Sensing or illuminating at different wavelengths
• CPC Class Codes: G06V 20/625 License plates
• CPC Class Codes: G09F 13/16 Signs formed of or incorporating reflecting elements or surfaces, e.g. warning signs having triangular or other geometrical shape
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Abstract

The inventors of the present application developed novel optically active materials, methods, and articles. One embodiment of the present application is an optically active article, comprising: an infrared-reflecting material positioned adjacent to an optically active substrate such that the infrared-reflecting material forms a pattern that can be read by an infrared sensor when the optically active substrate is illuminated by an infrared light source.

Another embodiment of the present application relates to a method of manufacturing an optically active article, comprising: obtaining an optically active sheeting; and positioning an infrared-reflecting material on the optically active sheeting to form a pattern. The optically active article may be, for example, a license plate.

Claims

1. A retroreflective article, comprising:

a multilayer optical film covering at least a portion of a retroreflective sheeting, which retroreflects incident light; and

wherein the multilayer optical film exhibits a relatively high reflectance for light within a first spectral range and a relatively low reflectance and high transmission for light within a second spectral range, wherein the multilayer optical film forms a pattern that can be read by a sensor;

wherein the first spectral range is between about 700 nm to about 1100 nm and the second spectral range is between about 400 nm to about 700 nm.

2. The retroreflective article of claim 1, wherein the retroreflective article is one of a license plate and a traffic sign.

3. The retroreflective article of claim 1, wherein the pattern includes one of a machine readable information, bar code, character, graphic and image.

4. The retroreflective article of claim 1, wherein the retroreflective sheeting is one of beaded sheeting or prismatic sheeting.

5. The retroreflective article of claim 1, wherein the multilayer optical film is attached to the retroreflective sheeting by one of lamination, bonding, mechanical fixation and use of an adhesive.