Electrochromic Rearview Mirror Incorporating a Third Surface Reflector

• US 20090040588A1
• Filed: 08/12/2008
• Published: 02/12/2009
• Est. Priority Date: 05/14/1999
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Cammenga, David J., Tonar, William L., Anderson, John S., Forgette, Jeffrey A., Stam, Joseph S., Bechtel, Jon H., Carter, John W.
• Granted Patent: US 7,663,798 B2
• Time in Patent Office: Days
• US Class Current: 359/267
• CPC Class Codes: B60Q 1/2665 on rear-view mirrors lighting devices for vehicle interior on or for rear-view mirrors B60Q3/258
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic 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: G02B 2027/0114 comprising dichroic elements
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02F 1/1506 caused by electrodeposition, e.g. electrolytic deposition of an inorganic material on or close to an electrode
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• 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 2001/1502 complementary cell
• CPC Class Codes: G02F 2001/1536 additional, e.g. protective, layer inside the cell
• CPC Class Codes: G02F 2201/34 reflector
• CPC Class Codes: G02F 2203/02 reflective
• CPC Class Codes: H10K 50/87 Arrangements for heating or cooling
• CPC Class Codes: H10K 59/8794 Arrangements for heating and cooling

Abstract

The inventive electrochromic mirror may be used in a vehicle rearview mirror assembly having a light source positioned behind the electrochromic mirror for selectively projecting light through the mirror and/or a light sensor positioned behind the electrochromic mirror for selectively receiving light through the mirror. The electrochromic mirror includes front and rear spaced elements each having front and rear surfaces and being sealably bonded together in a spaced-apart relationship to define a chamber, a layer of transparent conductive material disposed on the rear surface of the front element, an electrochromic material is contained within the chamber, and a second electrode overlies the front surface of the rear element in contact with the electrochromic material. The second electrode includes a layer of reflective material and a partially transmissive coating of and is disposed over substantially all of the front surface of the rear element. The second electrode further includes a region in front of the light source and/or light sensor that is at least partially transmissive.

Claims

1. A rearview mirror assembly for use in a vehicle, the assembly comprising:

a first substantially transparent substrate and a second substantially transparent substrate secured behind the first substrate, said second substrate including

a layer of reflective material being proximate a surface of said second substrate that is closest to said first substantially transparent substrate, and

a first layer of substantially transparent conductive material positioned between the layer of reflective material and the first substantially transparent substrate,

wherein the assembly exhibits a transmittance of at least about 5 percent in at least portions of the visible spectrum, and relative color neutrality.

2. A rearview mirror assembly according to claim 1, wherein the assembly is characterized by a value of C* of less than about 20.

3. A rearview mirror assembly according to claim 1 further comprising a second layer of substantially transparent conductive material positioned between said layer of reflective material and said second substrate.

4. A rearview mirror assembly according to claim 3, wherein the second layer of substantially transparent conductive material comprises zinc.

5. A rearview mirror assembly according to claim 1, wherein said first layer of substantially transparent conductive material comprises zinc.

6. A rear view mirror assembly according to claim 1, wherein said layer of reflective material is made of a silver allow including a combination of silver and an element selected from a group consisting of gold, platinum, rhodium, and palladium.

7. A rearview mirror assembly according to claim 1, wherein the electrochromic mirror has a reflectance of at least 35 percent.

8. A method for operating a rearview mirror assembly, the method comprising:

transmitting light, from a light source within the assembly, through an optical system to a field of view outside the assembly, wherein the optical system includes a first substrate having first and second surfaces, the first surface corresponding to an outside portion of the assembly, and a second substrate having a third surface, the second substrate secured to the first substrate, the third surface facing the second surface and

partially transmitting light incident on the third surface in such a manner as to provide for transmittance, by the optical system, of the light from the light source, of at least 5 percent in at least portions of the visible spectrum,

wherein the assembly exhibits relative color neutrality perceived in reflected ambient light.

9. A method according to claim 8, wherein the assembly is characterized by a C* value of less than about 20.

10. A method according to claim 8, wherein the assembly is characterized by minimized yellow hue perceived in reflection.

11. A method according to claim 10, wherein the assembly is characterized by a b* value of less than about 15.

12. A method according to claim 8, further comprising:

partially reflecting light incident on the third surface in such a manner as to provide for reflectance, by the optical system, of ambient light incident onto the assembly from the field of view outside the assembly, of at least 35 percent.

13. A method according to claim 8, wherein said assembly has a reflectance of at least about 65 percent.

14. A method according to claim 8, wherein the transmittance of light from the light source through the optical system is at least 10 percent.

15. A method according to claim 8, wherein the light source is a display.

16. A method according to claim 8, wherein reflecting light incident on the third surface includes reflecting light with an electrode overlying the third surface, said electrode comprising:

a first layer of a first material having a relatively high refractive index;

a second layer of a second material having a relatively low refractive index, the second layer being disposed on the first layer; and

a third layer of a third material having a relatively high refractive index, the third layer being disposed on the second layer.

17. A method according to claim 16, wherein the second material is a silver alloy including a combination of silver and an element selected from the group consisting of gold, platinum, rhodium, and palladium.

18. A method according to claim 16, wherein the second material is a silver alloy including about 94 percent silver and about 6 percent gold.

19. A method according to claim 16, wherein the electrode further comprises a forth layer of a transparent conductive material, the forth layer being deposited on the third layer.