VARIABLE REFLECTANCE MIRROR SYSTEM

• US 20140036339A1
• Filed: 09/30/2013
• Published: 02/06/2014
• Est. Priority Date: 07/12/2004
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Tonar, William L., Luten, Henry A., Neuman, George A., Anderson, John S., Dozeman, Gary J., Morgan, Tammy G.
• Granted Patent: US 9,910,310 B2
• Time in Patent Office: Days
• US Class Current: 359/267
• 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 laminated film 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, the variable mirror system having a front and a rear opposite thereto and comprising:

at least one substrate comprising a plurality of surfaces;

at least one reflective polarizer rearward of at least one said substrate with respect to the front of the mirror system;

wherein said at least one reflective polarizer comprises at least one of an anisotropic film, a wire-grid, a linear polarizer, a circular polarizer, and an optical retarder;

wherein said at least one reflective polarizer is configured to transmit light having a first polarization and reflect light having a second polarization;

wherein the second polarization is different from the first polarization;

a display rearward of at least one said reflective polarizer with respect to the front;

wherein said display is configured to emit light having the first polarization that is transmitted by said reflective polarizer;

an opaque reflectance-enhancement layer (OREL) rearward of said at least one reflective polarizer with respect to the front; and

wherein said opaque reflectance-enhancement layer is opaque to light in a non-display portion of the mirror system, such that light transmitted through said at least one reflective polarizer is reflected in said non-display portion.

2. A mirror system according to claim 1, being a multi-zone reflector and having, in addition to an opaque zone in the non-display portion of the mirror system, a transflective zone corresponding to a display portion of the mirror system.

3. A mirror system according to claim 2, wherein the opaque zone has a reflectance value exceeding 45 percent measured in ambient light incident onto the first surface.

4. A mirror system according to claim 2, wherein a color difference defined between the transflective and opaque zones in reflection of light incident from a CIE standard D65 standard illuminant onto the first surface is less than 5 C* units of the CIELAB color system.

5. A mirror system according to claim 2, wherein a color difference defined between the transflective and opaque zones in reflection of light incident from a CIE standard D65 standard illuminant onto the first surface is less than 3 C* units of the CIELAB color system.

6. A mirror system according to claim 2, comprising a net quarter-wave thin-film stack reflectance enhancement layer (REL) such as to increase a reflectance value of the mirror system as measured from the front in at least the transflective zone of the mirror system.

7. A mirror system according to claim 6, wherein the reflectance value of the transflective zone exceeds 55 percent.

8. A mirror system according to claim 6, wherein the reflectance value of the transflective zone exceeds 60 percent.

9. A mirror system according to claim 6, further comprising alternating layers of high and low refractive index materials adjacent to the net quarter-wave thin-films stack REL.

10. A mirror system according to claim 9, wherein the reflectance value of the opaque zone exceeds 50 percent.

11. A mirror system according to claim 9, wherein the reflectance value of the opaque zone exceeds 55 percent.

12. A mirror system according to claim 7, wherein the reflectance value of the opaque zone exceeds 60 percent.

13. A mirror system according to claim 9, wherein the REL includes one or more of antimony trioxide, cadmium sulfide, cerium oxide, tin oxide, zinc oxide, titanium dioxide or various titanium oxides, lanthanum oxide, lead chloride, praseodymium oxide, scandium oxide, silicon, tantalum pentoxide, thallium chloride, thorium oxide, yttrium oxide, zinc sulfide, zirconium oxide, zinc tin oxide, silicon nitride, indium oxide, molybdenum oxide, tungsten oxide, vanadium oxide, barium titanate, halfnium oxide, niobium oxide, and strontium titanate, and

wherein a layer of low refractive index material includes one or more of aluminum fluoride, aluminum oxide, silicon oxide, silicon dioxide, calcium fluoride, cerium fluoride, lanthanum fluoride, lead fluoride, lithium fluoride, magnesium fluoride, magnesium oxide, neodymium fluoride, sodium fluoride, thorium fluoride and a porous film with high density of voids.

14. A mirror system according to claim 1, wherein the OREL includes Cr, Al, Ag, Rh, Pd, Au, Ru, Stainless Steel, Pt, Ir, Mo, W, Ti, Cd, Co, Cu, Fe, Mg, Os, Sn, W, Zn and alloys, mixtures or combinations thereof.

15. A mirror system according to claim 1, wherein a ratio of intensity of light transmitted from the display towards the front to intensity of ambient light incident onto the first surface and reflected by the mirror system is greater than 1.

16. A mirror system according to claim 1, wherein a ratio of intensity of light transmitted from the display towards the front to intensity of ambient light incident onto the first surface and reflected by the mirror system is greater than 1.25.

17. A mirror system according to claim 1 configured to be devoid of extended distortion.

18. A mirror system according to claim 17, wherein the extended distortion is optical distortion, caused by a distortion of a surface of the mirror system, and, when measured from the front, is characterized by one or more of:

a) a curvature unit, of ONDULO phase-shifting deflectometry that quantifies surface distortions, a modulus of which does not exceed 0.04, and

b) an optical power value that quantifies surface distortions of the mirror system, measured in reflection, which value does not exceed 1,000 millidiopters; and

c) SW and LW distortion metrics of a wave-scan dual scale, which metrics quantify surface distortions with frequencies corresponding to ranges from about 0.1 mm to about 1.2 mm and from about 1.2 to about 12 mm, respectively, and at least one of which is less than 3.

19. A mirror system according to claim 1, wherein the OREL comprises a graded thickness in a region of transition between the transflective and opaque zones.

20. A mirror system according to claim 1, further comprising at least one of an optical prism and an electro-optic medium.

21. A mirror system according to claim 20, being an electro-optic mirror system and comprising:

a first transparent substrate including;

a first surface corresponding to the front;

a second surface opposite the first surface and carrying the first electrode; and

a second substrate having a third surface that carries a second electrode thereon and a fourth surface opposite the third surface,

the second substrate positioned in a spaced-apart and parallel relationship with respect to the first surface with the second and third surfaces facing each other to define a gap therebetween, the electro-optical medium disposed in the gap such as to change a transmittance value thereof in response to a voltage differential applied between the first and second electrodes.

22. A mirror system according to claim 21, wherein the electro-optical medium includes electro-chromic medium.

23. A mirror system according to claim 1, further comprising a third transparent substrate at the rear of the at least one reflective polarizer with respect to the front.

24. A mirror system according to claim 23, wherein the OREL is disposed on the third substrate.

25. A mirror system according to claim 1 having a total transmittance value in the range between about 25% to about 47%.

26. A mirror system according to claim 1, having a polarized transmittance value in a range between about 25% and about 89.5%.

27. A mirror system according to claim 1, further comprising a depolarizing optical element in front of the at least one reflective polarizer.

28. A mirror system according to claim 1, comprising a first reflective polarizer and a second reflective polarizer an axis of polarization of which forms an angle with respect to an axis of polarization of the first reflective polarizer.

29. A mirror system according to claim 28, wherein the reflectance value of the opaque zone exceeds 60 percent.

30. A mirror system according to claim 1, wherein the at least one reflective polarizer includes a dual brightness enhancement film.

31. A mirror system according to claim 1, configured to enable a ratio of a polarized transmittance value to an overall reflectance value characterizing the mirror system to exceed 1.

32. A variable reflectance mirror system having a front, for use in a rearview mirror assembly, the mirror system comprising:

at least one substrate having a plurality of surfaces;

at least one reflective polarizer rearward of at least one said substrate with respect to the front of the mirror system;

wherein said at least one reflective polarizer comprising at least one of an anisotropic film, a wiregrid, a linear polarizer, an elliptical polarizer, a circular polarizer, and an optical retarder;

a light source configured to emit light of a first polarization towards the front of the mirror system and that transmits through at least one said reflective polarizer;

wherein said at least one reflective polarizer reflects light of a second polarization;

wherein the second polarization is different than the first polarization; and

a net quarter-wave thin-film stack reflectance-enhancing layer (REL) in front of said light source with respect to the front of the mirror system;

wherein said net quarter-wave thin-film stack reflectance-enhancing layer contributes to an increase in reflection of the mirror system.

33. A mirror system according to claim 32, further comprising at least one of an optical prism and an electrochromic medium.

34. A mirror system according to claim 33, being an electrochromic mirror system and comprising:

a first transparent substrate including;

a first surface corresponding to the front;

a second surface opposite the first surface and carrying the first electrode;

a second substrate having a third surface that carries a second electrode thereon and a fourth surface opposite the third surface,

the second substrate positioned in a spaced-apart and parallel relationship with respect to the first surface with the second and third surfaces facing each other to define a gap therebetween, the electro-optical medium disposed in the gap such as to change a transmittance value thereof in response to a voltage differential applied between the first and second electrodes.

35. A mirror system according to claim 32, wherein the surface of the mirror system that carries the REL is in front of the reflective polarizer as seen from the front.

36. A mirror system according to claim 32, wherein a ratio of intensity of light transmitted from the light source towards the front to intensity of ambient light incident onto the first surface and reflected by the mirror system is greater than 1.

37. A mirror system according to claim 32, wherein a ratio of intensity of light transmitted from the light source towards the front to intensity of ambient light incident onto the first surface and reflected by the mirror system is greater than 1.25.

38. A mirror system according to claim 32, wherein the reflectance value of the transflective zone exceeds 50 percent.

39. A mirror system according to claim 32, wherein the reflectance value of the transflective zone exceeds about 60 percent.

40. A mirror system according to claim 32, configured to be devoid of extended distortion.

41. A mirror system according to claim 38, wherein the extended distortion is optical distortion, caused by a distortion of a surface of the mirror system, and, when measured from the front, is characterized by at least one of:

a) a curvature unit, of ONDULO phase-shifting deflectometry that quantifies surface distortions, a modulus of which does not exceed 0.04; and

b) an optical power value that quantifies surface distortions of the mirror system, measured in reflection, which value does not exceed 1,000 millidiopters; and

c) SW and LW distortion metrics of a wave-scan dual scale, which metrics quantify surface distortions with frequencies corresponding to ranges from about 0.1 mm to about 1.2 mm and from about 1.2 to about 12 mm, respectively, and at least one of which is less than 3.

42. A mirror system according to claim 32, further comprising an auxiliary lite of glass at the rear of the at least one reflective polarizer with respect to the front.

43. A mirror system according to claim 32, further comprising an opaque reflectance-enhancement layer (OREL) rearward of said at least one reflective polarizer with respect to the front;

wherein said opaque reflectance-enhancement layer is opaque to light in a non-display portion of the mirror system, such that light transmitted through the at least one reflective polarizer is reflected in the non-display portion.

44. A mirror system according to claim 43, wherein the OREL is disposed on an auxiliary lite of glass disposed at the rear of the at least one reflective polarizer with respect to the front the third substrate.

45. A mirror system according to claim 32, being a multi-zone reflector and including an opaque zone and a transflective zone.

46. A mirror system according to claim 45, wherein a color difference defined between the transflective and opaque zones in reflection of light incident from a CIE standard D65 standard illuminant onto the first surface is less than 5 C* units of the CIELAB color system.

47. A mirror system according to claim 46, wherein the at least one reflective polarizer includes a dual brightness enhancement film.

48. A variable reflectance mirror system having a front, for use in a rearview mirror assembly, the mirror system comprising:

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

a second substrate rearward of said first substrate with respect to the front of the mirror system, said second substrate comprising a second electrode disposed on a surface thereof;

wherein said first substrate and said second substrate are in a spaced-apart relationship to define a gap therebetween;

an electrochromic medium deployed in said gap;

wherein a transmittance of said electrochromic medium changes in response to a potential difference applied thereto;

at least one light source rearward of said second substrate, said light source adapted to emit light of a first polarization towards the front of the mirror system;

at least one reflective polarizer comprising a dual brightness enhancement film and positioned between said second substrate and said light source;

wherein light of the first polarization transmits through at least one said reflective polarizer;

wherein light of a second polarization is reflected by at least one said reflective polarizer;

wherein said second polarization is orthogonal to said first polarization;

an opaque reflectance-enhancement layer disposed rearward of said at least one reflective polarizer with respect to the front of the mirror system;

wherein said opaque reflectance-enhancement layer is configured to reflect light that transmits through at least one said reflective polarizer;

wherein said opaque reflectance-enhancement layer defines a transmissive zone and an opaque zone of the mirror system;

and

a net quarter-wave thin-film stack reflectance-enhancing layer in front of the light source with respect to the front of the mirror system;

wherein said net quarter-wave thin-film stack reflectance-enhancing layer contributes to an increase in reflection of the mirror system.