Retroreflecting optical construction

• US 9,551,816 B2
• Filed: 03/21/2016
• Issued: 01/24/2017
• Est. Priority Date: 04/15/2009
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Coggio, William D., Huizinga, John S., Steiner, Michael L., Watkins, Robert F., Hao, Encai, Kolb, William B., Zhu, Peiwang, Free, Michael Benton, Kolb, Brant U., Chen-Ho, Kui, Humpal, Paul E., Tapio, Scott M., Smith, Kenneth L.
• Primary Examiner(s): CHERRY, EUNCHA P
• Application Number:
  US15/076,149
• Publication Number:
  US 20160202398A1
• Time in Patent Office: 309 Days
• Field of Search: 359/529, 359/530, 359534-537, 359/539, 428/156, 428/163, 428/167, 428/172, 362/615
• US Class Current: 1/1
• CPC Class Codes: G02B 5/0236 the diffusion taking place within the volume of the element
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0247 by means of voids or pores
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet

Abstract

Retroreflecting optical constructions are disclosed. A disclosed retroreflecting optical construction includes a retroreflecting layer that has a retroreflecting structured major surface, and an optical film that is disposed on the retroreflecting structured major surface of the retroreflecting layer. The optical film has an optical haze that is not less than about 30%. Substantial portions of each two neighboring major surfaces in the retroreflecting optical construction are in physical contact with each other.

Claims

1. A retroreflecting optical construction comprising:

a retroreflecting layer having a retroreflecting structured major surface; and

an optical film disposed on a first portion of the retroreflecting structured major surface and comprising a binder, a plurality of particles and a plurality of voids.

2. The retroreflecting optical construction of claim 1, wherein the retroreflecting structured major surface exhibits a coefficient of retroreflection R_A that is not less than about 50 cd/(lux·

m²) for an observation angle of 0.2 degrees and an entrance angle of −

4 degrees.

3. The retroreflecting optical construction of claim 1, wherein the plurality of particles includes fumed silica.

4. The retroreflecting optical construction of claim 1, wherein the binder is at least one of radiation-curable and polymerizable.

5. The retroreflecting optical construction of claim 1, wherein the retroreflecting structured major surface exhibits a total light return that is not less than about 5% for incident visible light at an entrance angle of −

4 degrees.

6. The retroreflecting optical construction of claim 1, wherein the optical film has an effective index of refraction that is less than about 1.3.