Diffuse reflective articles

• US 6,780,355 B2
• Filed: 10/17/2002
• Issued: 08/24/2004
• Est. Priority Date: 10/24/1997
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Kaytor, Scott R, Kretman, Wade D
• Primary Examiner(s): Eashoo, Mark
• Application Number:
  US10/274,339
• Publication Number:
  US 20030118805A1
• Time in Patent Office: 677 Days
• Field of Search: 264/41, 264/49, 264/173.1, 264/175, 264/280
• US Class Current: 264/41
• CPC Class Codes: C08J 2323/02 not modified by chemical after treatment
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: F21S 41/37 characterised by their material, surface treatment or coatings
• CPC Class Codes: F21V 7/24 characterised by the material
• CPC Class Codes: F21V 7/28 characterised by coatings
• CPC Class Codes: G02B 5/021 the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
• CPC Class Codes: G02B 5/0247 by means of voids or pores
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249954 With chemically effective material or specified gas other than air, N, or carbon dioxide in void-containing component
• CPC Class Codes: Y10T 428/249958 Void-containing component is synthetic resin or natural rubbers
• CPC Class Codes: Y10T 428/249978 Voids specified as micro
• CPC Class Codes: Y10T 428/249986 Void-containing component contains also a solid fiber or solid particle
• CPC Class Codes: Y10T 428/24999 Inorganic
• CPC Class Codes: Y10T 428/249995 : Constituent is in liquid form
• CPC Class Codes: Y10T 428/249997 : Encapsulated liquid

Abstract

Diffuse reflective materials proximate to a structure formed by thermally induced phase separation of a thermoplastic polymer and a diluent providing enhanced flexibility and reflectivity especially in the visible wavelengths of 380-730 nanometers are described. Such materials find a wide variety of application among combinations with other reflective layers. The diffuse reflective articles are useful in backlight units of liquid crystal displays, lights, copy machines, projection system displays, facsimile apparatus, electronic blackboards, diffuse white standards, photographic lights and the like.

Claims

1. A method of making an article comprising a diffuse reflective material configured for positioning proximate to a structure, the method comprising:

providing a polymer component;

providing a diluent component, said diluent component being miscible with the polymer component at a temperature above the melting point of the polymer component or liquid-liquid phase separation temperature of the total solution of polymer and diluent;

combining the polymer component and diluent component to form a porous polymeric sheet having a first thickness; and

applying a force to the porous polymeric sheet to form a sheet having a second thickness.

2. The method of making an article according to claim 1, wherein the step of applying a force to the porous polymeric sheet comprises applying a mechanical force.

3. The method of making an article according to claim 1, wherein the step of applying a force to the porous polymeric sheet comprises calendering the porous polymeric sheet.

4. The method of making an article according to claim 1, wherein the article has a second thickness that 70 to 85 percent of the first thickness.

5. The method of making an article according to claim 1, wherein the article has a second thickness of from 150 to 300 μ

m.

6. The method of making an article according to claim 1, wherein the article has one or more elements configured to reduce optical coupling with a substrate.