Very thin highly light reflectant surface and method for making and using same

• US 6,015,610 A
• Filed: 11/14/1997
• Issued: 01/18/2000
• Est. Priority Date: 01/06/1995
• Status: Expired due to Term

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Inventors: Minor, Raymond B., Wu, Huey Shen, McGregor, Gordon L., Lash, Daniel J.
• Primary Examiner(s): Copenheaver, Blaine
• Application Number:
  US08/970,490
• Time in Patent Office: 795 Days
• Field of Search: 428/315.7, 428/317.9, 428/339, 428/421, 428/422, 428/318.4, 428/319.1, 359/515, 359/597, 362/341
• US Class Current: 428/315.7
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: G02B 1/04 made of organic materials, e.g. plastics G02B1/08 takes precedence
• CPC Class Codes: G02B 5/0221 the surface having an irregular structure G02B5/0226 takes precedence
• 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 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: Y10T 428/249979 Specified thickness of void-containing component [absolute or relative] or numerical cell dimension
• 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 428/269 including synthetic resin or polymer layer or component

Abstract

The present invention provides and employs a very thin yet highly light reflective material for use in providing diffuse reflectivity of light, especially in tightly confined applications such as in laptop computer displays. The present invention uses an expanded polytetrafluoroethylene (PTFE) comprising a microstructure of polymeric nodes and fibrils combined with a coating or filler of material having a high index of refraction, such as titanium dioxide. The material of the present invention demonstrates exceptional diffuse reflectivity across a wide spectrum of visible and infrared light. Additionally, the material of the present invention provides many properties that have been previously unavailable in thin, highly diffuse reflective material, including a high degree of malleability, moldability and flexibility, and effective reflectivity even at very thin cross-sections.

Claims

1. A light reflective material comprising

an expanded polytetrafluoroethylene having a micro structure of polymeric nodes, fibrils, and voids;

a coating on the nodes and fibrils of the expanded polytetrafluoroethylene comprising particles with an index of refraction greater than 1.5;

wherein the light reflective material has a total thickness of no more than 0.3 mm; and

wherein the light reflective material provides diffuse reflectivity of at least 96% of visible light with a wavelength between at least 450 to 750 nm striking the reflectant material.

2. The light reflective material of claim 1 wherein the coating comprises particle with an index of refraction of greater than 2.

3. The light reflective material of claim 2 wherein the coating comprises titanium dioxide.

4. A light reflective material comprising an expanded polvetrafluoroethylene having a microstructure of polymer nodes, fibrils, and voids;

a coating on the nodes and fibrils of the expanded polytetraflouroethylene comprising particles with an index of refraction greater than 1.5;

wherein the light reflective material has a total thickness of no more than 0.2 mm; and

the light reflective material provides diffuse reflectivity of at least 95% of visible light with a wavelength between at least 450 to 750 nm striking the light reflective material.

5. A light reflective material comprising an expanded polyetrafluoroethylene having a microstructure of polymer nodes, fibrils, and voids;

a coating on the nodes and fibrils of the expanded polytetraflouroethylene comprising particles with an index of refraction greater than 1.5;

wherein the light reflective material has a total thickness of no more than 0.15 mm; and

the light reflective material provides diffuse reflectivity of at least 93% of visible light with a wavelength between at least 450 to 750 nm striking the light reflective material.

6. A light reflective material comprising an expanded polvetrafluoroethylene having a microstructure of polymer nodes, fibrils, and voids;

a coating on the nodes and fibrils of the expanded polytetraflouroethylene comprising particles with an index of refraction greater than 1.5;

wherein the light reflective material has a total thickness of no more than 0.3 mm; and

wherein the light reflective material provides diffuse reflectivity of at least 97% of visible light with a wavelength between at least 450 to 750 nm striking the light reflective material.

7. A method of providing improved diffuse reflectivity of light comprising

providing a reflectant material comprising an expanded polytetrafluoroethylene having polymeric nodes interconnected by fibrils defining microporous voids therein;

wherein the expanded PTFE is combined with a high index of refraction material, the reflectant material is equal to or less than 0.30 mm in thickness;

mounting the reflectant material to cause light energy to reflect off it; and

using the reflectant material to provide diffuse reflectivity with equal to or greater than 97% of visible light with a wavelength between at least 450 to 750 nm striking the reflectant material.

8. The method of claim 7 wherein said high index of refraction material is a coating on the expanded PTFE nodes and fibrils.

9. The method of claim 8 that further comprises providing a reflectant material with a thickness of equal to or less than 0.3 mm.

10. The method of claim 8 that further comprises providing a reflectant material with a thickness of less than 0.20 mm.

11. The method of claim 8 that further comprises providing a reflectant material with a thickness of less than 0.1 mm.

12. The method of claim 7 wherein said high index of refraction material is particles in the microporous voids in the reflectant material.

13. A method of providing improved diffuse reflectivity of light comprising

providing a reflectant material comprising an expanded polytetrafluoroethylene having polymeric nodes interconnected by fibrils defining microporous voids therein;

wherein the expanded PTFE is combined with a high index of refraction material, the reflectant material is equal to or less than 0.25 mm in thickness;

mounting the reflectant material to cause light energy to reflect off it; and

using the reflectant material to provide diffuse reflectivity with equal to or greater than 96% of visible light with a wavelength between at least 450 to 750 nm striking the reflectant material.

14. A method of providing improved diffuse reflectivity of light comprising

providing a reflectant material comprising an expanded polytetrafluoroethylene having polymeric nodes interconnected by fibrils defining microporous voids therein;

wherein the expanded PTFE is combined with a high index of refraction material, the reflectant material is equal to or less than 0.20 mm in thickness;

mounting the reflectant material to cause light energy to reflect off it; and

using the reflectant material to provide diffuse reflectivity with equal to or greater than 95% of visible light with a wavelength between at least 450 to 750 nm striking the reflectant material.

15. A method of providing improved diffuse reflectivity of light comprising

providing a reflectant material comprising an expanded polytetrafluoroethylene having polymeric nodes interconnected by fibrils defining microporous voids therein;

wherein the expanded PTFE is combined with a high index of refraction material, the reflectant material is equal to or less than 0.15 mm in thickness;

mounting the reflectant material to cause light energy to reflect off it; and

using the reflectant material to provide diffuse reflectivity with equal to or greater than 93% of visible light with a wavelength between at least 450 to 750 nm striking the reflectant material.