Thin-Film Coatings, Electro-Optic Elements and Assemblies Incorporating These Elements

• US 20110002028A1
• Filed: 06/21/2010
• Published: 01/06/2011
• Est. Priority Date: 03/03/2006
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Anderson, John S., Forgette, Jeffrey A., Neuman, George A., Luten, Henry A.
• Granted Patent: US 8,274,729 B2
• Time in Patent Office: Days
• US Class Current: 359/267
• CPC Class Codes: B60R 1/00 Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
• CPC Class Codes: B60R 1/04 mounted inside vehicle B60R1/025, B60R1/08 take precedence
• CPC Class Codes: B60R 1/06 mounted on vehicle exterior B60R1/025, B60R1/08 take precedence
• CPC Class Codes: B60R 1/083 Anti-glare mirrors, e.g. "day-night" mirrors
• CPC Class Codes: B60R 1/085 using a combination of interchangeable reflecting surfaces, e.g. reversible mirrors
• CPC Class Codes: B60R 1/1207 with lamps; with turn indicators
• CPC Class Codes: B60R 2001/1215 with information displays
• CPC Class Codes: B60R 2001/1223 with sensors or transducers
• CPC Class Codes: B60R 2001/1253 with cameras, video cameras or video screens
• CPC Class Codes: B60R 2300/108 using 'non-standard' camera systems, e.g. camera sensor used for additional purposes i.a. rain sensor, camera sensor split in multiple image areas
• CPC Class Codes: E06B 3/6722 with adjustable passage of light
• CPC Class Codes: G02F 1/157 Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 2201/34 reflector

Abstract

Electro-optic elements are becoming commonplace in a number of vehicular and architectural applications. Various electro-optic element configurations provide variable transmittance and or variable reflectance for windows and mirrors. The present invention relates to various thin-film coatings, electro-optic elements and assemblies incorporating these elements.

Claims

1. A mirror system for use in a vehicular rearview assembly equipped with a light source generating light that is transmitted from within the rearview assembly through said mirror system to a field of view (FOV) outside the assembly, the generated light having a generated spectrum, the mirror system comprising an electrochromic (EC) element, the EC-element including:

a first substantially transparent substrate having first and second surfaces, the second surface including a transparent electrode carried thereon, the first substrate corresponding to an outside portion of said assembly;

a second substrate having third and fourth surfaces, the second and first substrates being mutually secured in a parallel and space-apart relationship thereby defining a gap between the second and third surfaces, the third surface having a spectrally-selective transflective thin-film stack carried thereon, said spectrally-selective transflective stack having a multi-band transmission spectrum; and

an electrochromic medium inside said gap,

wherein said mirror system is characterized by a C* value not exceeding 20, as measured in light produced by a standard D₆₅ illuminant and reflected by said mirror system.

2. A mirror system according to claim 1, wherein said C* value does not exceed 20 as measured in specular reflection at any angle between zero and thirty degrees.

3. A mirror system according to claim 1, further comprising a liquid-crystal display (LCD) positioned between the light source and the mirror system, the LCD having an optical transmission spectrum, the spectrally-selective transflective stack being configured to have said multi-band transmission spectrum match said optical transmission spectrum.

4. A mirror system according to claim 3, wherein multiple spectral bands of said multi-band transmission spectrum align with spectral bands of said generated spectrum.

5. A mirror system according to claim 1, wherein said transflective thin-film stack comprises a sequence of adjoining layers including a first metallic layer, a first dielectric layer, a second metallic layer, a second dielectric layer, and a third metallic layer thereby rendering said mirror system to have an overall photopic reflectance of at least 55 percent measured in light produced by a standard D₆₅ illuminant.

6. A mirror system according to claim 1, wherein a first b* value, measured in light produced by a D₆₅ illuminant and reflected by a peripheral area of the mirror system, matches a second b* value measured in light produced by the D₆₅-illuminant and reflected by a central area of the mirror system, the central area being enclosed by the peripheral area.

7. A mirror system according to claim 6, wherein the second surface further includes a thin-film band of chrome circumferentially disposed in a peripheral area thereof.

8. A mirror system according to claim 1, wherein said mirror system is characterized by an overall photopic reflectance greater than 65 percent measured in light produced by a standard D₆₅ illuminant.

9. A mirror system according to claim 1, wherein said mirror system is characterized by an overall photopic reflectance greater than 75 percent measured in light produced by a standard D₆₅ illuminant.

10. A mirror system according to claim 1, wherein said mirror system is characterized by a C* value not exceeding 15, as measured in light produced by a standard D₆₅ illuminant and specularly reflected by said mirror system at any angle in a range of zero to thirty degrees.

11. A mirror system according to claim 1, wherein said mirror system is characterized by a C* value not exceeding 5, as measured in light produced by a standard D₆₅ illuminant and specularly reflected by said mirror system at any angle in a range of zero to thirty degrees.

12. A mirror system according to claim 1, further including a seal sealably bonding the second and third surfaces, wherein said spectrally-selective transflective stack extends beyond the seal towards a perimeter of the second substrate and is configured so as to make the seal visible from the fourth surface.

13. A mirror system for use in a vehicular rearview assembly equipped with a light source generating light that is transmitted from within the rearview assembly through said mirror system to a field of view (FOV) outside the assembly, the generated light having a generated spectrum, the mirror system comprising an electrochromic element, the electrochromic (EC) element including:

a first substantially transparent substrate having first and second surfaces, the second surface including a transparent electrode carried thereon, the first substrate corresponding to an outside portion of said assembly;

a second substrate having third and fourth surfaces, the second and first substrates being mutually secured in a parallel and space-apart relationship thereby defining a gap between the second and third surfaces, the third surface having a spectrally-selective transflective thin-film stack carried thereon, said spectrally-selective transflective stack having a multi-band transmission spectrum; and

an electrochromic medium inside said gap,

wherein said mirror system is characterized by a C* value not exceeding 20, as measured in light produced by a standard D₆₅ illuminant and specularly reflected by said mirror system at any angle within a range of zero to thirty degrees, and

wherein at least one of the transparent electrode and the spectrally-selective transflective stack is characterized by a mean peak-to-valley surface roughness less than or equal to approximately 150 Å

.

14. A mirror system according to claim 13, wherein said transflective thin-film stack comprises a sequence of adjoining layers including a first metallic layer, a first dielectric layer, a second metallic layer, a second dielectric layer, and a third metallic layer thereby rendering said mirror system to have an overall photopic reflectance of at least 55 percent measured in light produced by a standard D₆₅ illuminant.

15. A mirror system according to claim 13, wherein said C* value does not exceed 15.

16. A mirror system according to claim 15, wherein said C* value does not exceed 5.

17. A mirror system according to claim 14, wherein the second surface further includes a thin-film band of chrome circumferentially disposed in a peripheral area thereof.

18. A mirror system according to claim 15, further including a seal sealably bonding the second and third surfaces, wherein said spectrally non-uniform transflective stack extends beyond the seal towards a perimeter of the second substrate and is configured so as to make the seal visible from the fourth surface.

19. A mirror system according to claim 14, further comprising a liquid-crystal display (LCD) positioned between the light source and the mirror system, the LCD having an optical transmission spectrum, the spectrally-selective transflective stack being configured to have said multi-band transmission spectrum match said optical transmission spectrum.

20. A mirror system according to claim 14, wherein the transparent electrode is characterized by a bulk resistance of 200 microOhm-cm.