Rearview Mirror Assemblies With Anisotropic Polymer Laminates

• US 20090296190A1
• Filed: 07/01/2009
• Published: 12/03/2009
• Est. Priority Date: 07/12/2004
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Neuman, George A., Tonar, William L., Anderson, John S., Luten, Henry A., Dozeman, Gary J., Morgan, Tammy G.
• Granted Patent: US 8,545,030 B2
• Time in Patent Office: Days
• US Class Current: 359/247
• CPC Class Codes: B32B 2255/00 Coating on the layer surface
• CPC Class Codes: B32B 2307/41 Opaque
• CPC Class Codes: B32B 2307/416 Reflective
• CPC Class Codes: B32B 2307/42 Polarizing, birefringent, filtering
• CPC Class Codes: B32B 2307/704 Crystalline
• CPC Class Codes: B32B 2307/706 Anisotropic
• CPC Class Codes: B32B 2307/748 Releasability
• CPC Class Codes: B32B 2551/08 Mirrors
• CPC Class Codes: B32B 2605/00 Vehicles
• CPC Class Codes: B32B 2605/006 Transparent parts other than made from inorganic glass, e.g. polycarbonate glazings
• CPC Class Codes: B32B 27/06 as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a layer of a particular substance B32B9/045; next to a bituminous or tarry layer B32B11/046; next to a water setting substance layer B32B13/12; next to a metal layer B32B15/08; next to a glass layer B32B17/10; next to a layer formed of natural mineral fibres or particles B32B19/045; next to a wood layer B32B21/08; next to a cellulosic plastic layer B32B23/08; next to a natural or synthetic rubber layer B32B25/08
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/283 comprising polysiloxanes
• CPC Class Codes: B32B 27/286 comprising polysulphones; polysulfides
• CPC Class Codes: B32B 27/304 comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
• CPC Class Codes: B32B 27/308 comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 27/365 comprising polycarbonates
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: G02B 27/28 : for polarising used in stereoscopes G02B30/25
• CPC Class Codes: G02B 5/3058 : comprising electrically conductive elements, e.g. wire grids, conductive particles
• CPC Class Codes: G02B 5/3083 : Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02F 1/133509 : Filters, e.g. light shielding masks
• CPC Class Codes: G02F 1/133536 : Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133548 : Wire-grid polarisers
• CPC Class Codes: G02F 1/1339 : Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G02F 1/13439 : characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/137 : characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
• CPC Class Codes: G02F 1/13756 : the liquid crystal selectively assuming a light-scattering state G02F1/1334, G02F1/13718 take precedence
• CPC Class Codes: G02F 1/155 : Electrodes
• CPC Class Codes: G02F 1/157 : Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 1/161 : Gaskets; Spacers; Sealing of cells; Filling or closing of cells
• CPC Class Codes: G02F 2201/44 : Arrangements combining different electro-active layers, e.g. electrochromic, liquid crystal or electroluminescent layers
• CPC Class Codes: Y10T 156/10 : Methods of surface bonding and/or assembly therefor

Abstract

Anisotropic film laminates for use in image-preserving reflectors such as rearview automotive mirror assemblies, and related methods of fabrication. A film may comprise an anisotropic layer such as a light-polarizing layer and other functional layers. The film having controlled water content is heated under omnidirectional pressure and vacuum to a temperature substantially equal to or above a lower limit of a glass-transition temperature range of the film so as to be laminated to a substrate. The laminate is configured as part of a mirror structure so as to increase contrast of light produced by a light source positioned behind the mirror structure and transmitted through the mirror structure towards a viewer. The mirror structure is devoid of any extended distortion and is characterized by SW and LW values less than 3, more preferably less than 2, and most preferably less than 1.

Claims

1. A variable reflectance mirror system for use in a rearview mirror assembly having a light source transmitting light of a first polarization through the mirror system, the mirror system comprising:

a first substrate having a first electrode disposed on a surface thereof;

a second substrate having a second electrode disposed on a surface thereof, the first and second substrates placed in a spaced-apart relationship to define a gap therebetween;

an electro-optic medium deployed in the gap, the electro-optic medium characterized by transmittance changing in response to a voltage difference applied between the first and second electrodes;

a reflective polarizer including an anisotropic film, the reflective polarizer positioned between the second substrate and the light source such that the light emitted by the light source passes through the reflective polarizer, and where the reflective polarizer reflects light of a second polarization, the second polarization being opposite the first polarization,

wherein the mirror system is substantially devoid of any extended distortion.

2. A mirror system according to claim 1, wherein the mirror system is characterized by SW and LW values that are less than 3.

3. A mirror system according to claim 2, wherein the mirror system is characterized by SW and LW values that are less than 2.

4. A mirror system according to claim 3, wherein the mirror system is characterized by SW and LW values that are less than 1.

5. A mirror system according to claim 1, wherein the anisotropic film is birefringent.

6. A mirror system according to claim 1, wherein the anisotropic film is part of a laminate disposed within the mirror system.

7. A mirror system according to claim 1, wherein the anisotropic film is laminated between the second substrate and a superstrate.

8. A mirror system according to claim 7, wherein the mirror system includes a coating configured to increase an overall reflectance of the mirror system, the coating disposed on at least one of the second substrate and the superstrate.

9. A mirror system according to claim 7, wherein the superstrate is releasably adhered to the anisotropic film.

10. A mirror system according to claim 7, wherein the light source is the superstrate of the laminate.

11. A mirror system according to claim 7, further comprising an opacifying layer adjacent a surface of one of the second substrate and superstrate, the opacifying layer substantially completely covering the surface outside of a transflective zone of the mirror system.

12. A mirror system according to claim 9, wherein the opacifying layer is characterized by a graded thickness.

13. A variable reflectance mirror system for use in a rearview mirror assembly having a light source transmitting light of a first polarization through the mirror system, the mirror system comprising

an optical element having a proximal side and a distal side, the mirror element reflecting ambient light incident upon the proximal side;

and

a laminate including an anisotropic plastic film structure, the anisotropic plastic film structure substantially transmitting light of the first polarization and substantially reflecting light of a second polarization, the second polarization being opposite the first polarization, the anisotropic plastic film structure disposed between the distal side of the optical element and the light source such that the light emitted by the light source passes through the laminate,

wherein the mirror system is substantially devoid of any extended distortion.

14. A mirror system according to claim 13, wherein the optical element includes at least one of an electro-optic medium and an optical prism.

15. A mirror system according to claim 13, wherein the anisotropic film is laminated between the optical element and a superstrate.

16. A mirror system according to claim 15, wherein the light source is the superstrate of the laminate.

17. A mirror system according to claim 13, wherein the mirror system is characterized by SW and LW values that are less than 3.

18. A mirror system according to claim 17, wherein the mirror system is characterized by SW and LW values that are less than 2.

19. A mirror system according to claim 18, wherein the mirror system is characterized by SW and LW values that are less than 1.

20. A mirror system according to claim 13, wherein the laminate is a stand-alone element.

21. A mirror system according to claim 13, wherein the light source includes an LCD.

22. A mirror system according to claim 13, wherein the mirror system is a multi-zone reflector.

23. A mirror system according to claim 22, further comprising an opacifying layer disposed on a surface of one of the optical element and the superstrate substantially outside of a transflective zone of the mirror system, the opacifying layer characterized by a non-uniform thickness.

24. A mirror system according to claim 22, further comprising a layer of material configured to increase an overall reflectance of the mirror system, the layer of material disposed on at least one of the optical element and the superstrate.

25. An optical element for increasing a contrast of light generated by a light source and transmitted through a mirror structure of an automotive rearview mirror assembly, the optical element comprising:

an optical substrate having a surface; and

a layered structure adhered to the surface, the layered structure including an anisotropic layer transmitting light of a first polarization and reflecting light of a second polarization that is opposite to the first polarization, the layered structure characterized by a range of glass transition temperatures,

wherein the optical element is characterized by SW and LW values that are less than 3.

26. The optical element according to claim 25, wherein the optical element is substantially devoid of any extended distortion.

27. An optical element according to claim 25, wherein the optical element is characterized by SW and LW values that are less than 2.

28. An optical element according to claim 25, wherein the optical element is characterized by SW and LW values that are less than 1.

29. An optical element according to claim 25, wherein the optical element is fabricated according to a method comprising:

forming a composite including the anisotropic film structure disposed between a first substrate and a second substrate, the anisotropic film structure characterized by water content less than about 0.6 weight-percent; and

applying heat and pressure to the composite to form a laminate that is substantially devoid of any extended distortion, the heat being defined by a range of glass transition temperatures characterizing the film structure, the pressure being between about 50 psi and about 500 psi.

30. An optical element according to claim 28, further comprising at least one of a first layer and a second layer disposed adjacent the surface, the first layer configured to render the surface substantially opaque and the second layer configured to increase the reflectance of the optical element.