Electro-optic device

• US 5,202,787 A
• Filed: 01/10/1992
• Issued: 04/13/1993
• Est. Priority Date: 01/10/1992
• Status: Expired due to Term

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Barrett, Larry L., Tonar, William L., Byker, Harlan J.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): Lester, Evelyn A.
• Time in patent office: 459 Days
• Field of Search: 359/265, 359/267, 359/602, 359/604, 359/74
• US Class Current: 359/267
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: G02F 1/133502 Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/155 Electrodes

Abstract

Electro optic devices incorporating an improved configuration of elements which dramatically reduces light scattering and haziness with relatively inexpensive coated glass. The devices are liquid or gel containing electro optic devices, such as an electrochromic automatic rearview mirror for automotive vehicles, which has for at least one of its walls a sheet of glass coated with a transparent conductive coating. The combination of the coated glass, which has a tendency to have an optically rough surface, and the liquid or gel electro optic material reduces the scattering of any incident light by wetting out the rough optical surface of the coated glass, thereby improving the optical quality. The coated glass scatters between 0.2 and 4.0% of visible white light prior to assembly into the device.

Claims

1. An electro-optic device including a plurality of walls defining a compartment, at least one of said walls comprising a sheet of glass coated with a transparent electronic conductive layer such that the coated glass scatters between 0.2 and 4.0% of the visible white light passing through the coated glass when it is in contact with air.

2. A device according to claim 1 wherein the device is a solution-phase electrochromic device.

3. A device according to claim 1 wherein the device is a variable reflectance rearview mirror for use with a motor vehicle.

4. A device according to claim 3 wherein the sheet resistance of the transparent electronic conductive layer is 1-40 ohms per square.

5. A device according to claim 1 wherein the device is a solution-phase electrochromic, variable reflectance rearview mirror for automotive vehicles.

6. A device according to claim 5 wherein the sheet resistance of the transparent electronic conductive layer is 1-40 ohms per square.

7. A device according to claim 1 wherein the device is a dynamic scattering liquid crystal device.

8. A variable reflectance electro-optic device comprising as a variable transmittance component a single-compartment, self-erasing, solution-phase electrochromic device wherein the compartment is defined by at least one wall comprising a sheet of glass coated with a transparent electronic conductive layer such that the coated glass scatters between 0.2 and 4.0% of the visible white light passing through the coated glass when it is in contact with air.

9. A variable reflectance rearview mirror for automotive vehicles, said mirror comprising as a variable transmittance component a single-compartment, self-erasing, solution-phase electrochromic device wherein the compartment is defined by at least one wall including a sheet of glass coated with a transparent electronic conductive layer such that the coated glass scatters between 0.2 and 4.0% of the white light passing through the coated glass when it is in contact with air.

10. A device according to claim 9 wherein the sheet resistance of the transparent electronic conductive layer is 1-40 ohms per square.

11. A mirror according to claim 9 which has a range of reflectance from greater than 70% to less than 10%.

12. A mirror according to claim 9 wherein the electrochromic device includes electronic conductive layers and is gray-scale controllable over a range of reflectance by applying electrical potential differences between the electrode layers.

13. A mirror according to claim 9 wherein the electrochromic device comprises two planar, parallel spaced-apart electrode layers to which DC current is provided through leads connected to a DC power source.

14. A variable reflectance rearview mirror for an automotive vehicle comprising as a variable transmittance component a single-compartment, self-erasing, solution-phase electrochromic device, the compartment being defined by a plurality of walls, at least one of the walls of the compartment comprising a sheet of glass coated with a transparent electronic conductive layer such that the coated glass scatters between 0.2 and 4.0% of the visible white light passing through the coated glass when it is in contact with air, said electrochromic device including two planar, parallel spaced-apart electronic conductive layers to which electrical current is provided through leads connected to a power source, said transparent electronic conductive layer being in contact with a solution having an index of refraction higher than air, the difference in the index of refraction between the coated surface and air being larger than the difference in the index of refraction between the coated surface and the electrochromic solution.

15. A rearview mirror as set forth in claim 14 wherein said mirror has a range of reflectance from greater than 70% to less than 10%, said electrochromic device being gray-scale controllable over a range of reflectance by applying electrical potential differences between the electrode layers of the device.