OPTICALLY ACTIVE MATERIALS AND ARTICLES AND SYSTEMS IN WHICH THEY MAY BE USED

• US 20100151213A1
• Filed: 12/15/2008
• Published: 06/17/2010
• Est. Priority Date: 12/15/2008
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Smithson, Robert L.W., Biernath, Rolf W.
• Granted Patent: US 8,865,293 B2
• Time in Patent Office: Days
• US Class Current: 428/195.100
• 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. 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.

2. The optically active article of claim 1, wherein the optically active substrate is retroreflective or reflective.

3. The optically active article of claim 2, wherein the retroreflective substrate includes prismatic sheeting or beaded sheeting.

4. The optically active article of claim 1, wherein the infrared-reflecting material is a multilayer optical film.

5. The optically active article of claim 1, wherein the infrared-reflecting material is transparent to visible light.

6. The optically active article of claim 1, wherein the optically active substrate is substantially transparent to visible light.

7. The optically active article of claim 1, further comprising an underlying pattern that is visible in the visible light spectrum through the optically active substrate.

8. The optically active article of claim 1, wherein the pattern includes at least one of machine readable information, graphics, images, alphanumeric characters, bar codes, or other indicia.

9. The optically active article of claim 1, wherein the visibility of the pattern differs based on the angle at which the license plate is viewed.

10. The optically active article of claim 1, wherein the article is a signage selected from a group consisting essentially of a license plate, a validation sticker, a usage permit, an identification label, or a tag.

11. A method of manufacturing a retroreflective article, comprising:

obtaining a retroreflective sheeting; and

positioning an infrared-reflecting material on the retroreflective sheeting to form a pattern.

12. The method of claim 11, wherein the article is a license plate, a validation sticker, a usage permit, an identification label, or a tag.

13. The method of claim 11, further comprising:

affixing the retroreflective sheeting to a license plate base.

14. The method of claim 11, further comprising illuminating the retroreflective sheeting with an infrared light source to facilitate reading of the pattern by an infrared sensor.

15. The method of claim 11, wherein the retroreflective sheeting is one of prismatic sheeting or beaded sheeting.

16. The method of claim 11, wherein the infrared-reflecting material is a multilayer optical film.

17. The method of claim 11, wherein the infrared-reflecting material is substantially transparent to visible light.

18. The method of claim 11, wherein the pattern includes at least one of machine readable information, graphics, images, alphanumeric characters, bar code, or other indicia.

19. A retroreflective article, comprising:

a multilayer optical film covering at least a portion of a retroreflective sheeting; and

wherein the multilayer optical film exhibits a relatively high reflectance for light within a first spectral range and a relatively low reflectance for light within a second spectral range.

20. The retroreflective article of claim 19, 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.