High contrast retroreflective sheeting and license plates

Patent metadata

Field	Value
Publication number	US-9937879-B2
Application number	US-201514830421-A
Country	US
Kind code	B2
Filing date	Aug 19, 2015
Priority date	Oct 8, 2009
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

The present disclosure relates to the formation of high contrast, wavelength independent retroreflective sheeting made by including a light scattering material on at least a portion of the retroreflective sheeting. The light scattering material reduces the brightness of the retroreflective sheeting without substantially changing the appearance of the retroreflective sheeting when viewed under scattered light.

First claim

What is claimed is:

1. A retroreflective article comprising:
a retroreflective sheeting comprising indicia including a light scattering material, wherein the light scattering material is placed under the indicia; and wherein the light scattering material is the same color as the retroreflective sheeting.

2. A license plate comprising the retroreflective article of claim 1 .

3. An optical character recognition system, comprising:
an optical character recognition camera;
a light source emitting infra-red light that is coaxial with the optical character recognition camera; and
the retroreflective sheeting of claim 1 ;
wherein the retroreflective sheeting is irradiated using the light source and imaged using the optical character recognition camera thereby recognizing characters of the indicia.

4. The optical character recognition system of claim 3 , wherein the light scattering material is a surface-scattering material.

5. The optical character recognition system of claim 3 , wherein the light scattering material is one of an ink, a toner, a dye, and a tape.

6. The optical character recognition system of claim 3 , wherein the light scattering material is a surface that has been selectively roughened.

7. The optical character recognition system of claim 3 , wherein the light scattering material is one of colored, clear, and white.

8. The optical character recognition system of claim 3 , wherein the retroreflective sheeting is disposed on at least a portion of a license plate.

Assignees

• 3M Innovative Properties Co

Inventors

• Fleming Patrick R
• Dahlin Thomas J
• Kusilek Thomas V
• Smithson Robert L

Classifications

• Y10T428/24355

  Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.] · CPC title

• Y10T428/24802

  Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.] · CPC title

• B60R13/10 Primary

  Registration, licensing, or like devices · CPC title

• G09F13/16

  Signs formed of or incorporating reflecting elements or surfaces, e.g. warning signs having triangular or other geometrical shape · CPC title

• G06K9/18

  Physics · mapped topic