Variable transmittance electrochromic devices

• US 6,211,994 B1
• Filed: 01/04/2000
• Issued: 04/03/2001
• Est. Priority Date: 03/31/1986
• Status: Expired due to Fees

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Byker, Harlan J.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Lester, Evelyn A.
• Application Number:
  US09/477,470
• Time in Patent Office: 455 Days
• Field of Search: 359/265-275
• US Class Current: 359/272
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: C07D 498/04 Ortho-condensed systems
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G01R 13/40 using modulation of a light beam otherwise than by mechanical displacement, e.g. by Kerr effect visual indication of correct tuning H03J3/14
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• 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 2001/15145 the electrochromic layer comprises a mixture of anodic and cathodic compounds

Abstract

Single-compartment, self-erasing, solution-phase electrochromic devices, solutions of electrochromic compounds for use as media of variable transmittance in such devices, and electrochromic compounds for such solutions are provided. The devices of the invention are surprisingly stable to cycling between light and dark states, have continuously variable transmittance to light as a function of electrical potential applied across the solution in a device, and have transmittance that can be varied over more than a factor of 10, from clear to dark or from dark to clear, in several seconds. Thus, the devices are especially suitable as variable transmittance components of variable transmission light filters, including windows, and variable reflectance mirrors, including anti-glare rearview mirrors in automobiles. Also provided are improved variable reflectance mirrors, wherein transmittance of reflected light is varied by thermochromic, photochromic or electro-optic means and wherein the reduction in transmittance which is required to eliminate perceptible reflection of an object to the eyes of an observer is reduced by disposing the plane of the highly reflective surface of the mirror at an angle with respect to the plane of the surface through which light from the object enters the mirror.

Claims

1. An electrochromic device, comprising a single-compartment, self-erasing, solution-phase variable transmittance component that provides continuously variable transmittance over a range of transmittance as a function of a potential difference applied, and wherein the continuously variable transmittance component comprises an acrylic material and a UV stabilizer.

2. The electrochromic device according to claim 1, wherein said acrylic material is a thickening material.

3. The electrochromic device according to claim 1, wherein said acrylic material is a gel.

4. The electrochromic device according to claim 1, wherein the sheet resistance of a transparent electrode layer of the electrochromic device is less than 40 ohms per square.

11. An electrochromic device according to any of claims 1, 5, 7, and 10, wherein said device is an electrochromic window that has an area of at least about 162 square centimeters.

5. An electrochromic device, comprising a solution-phase, single-compartment, self-erasing continuously variable transmittance component, where said electrochromic device is gray-scale controllable over a range of transmittance and wherein the continuously variable transmittance component comprises a gel and a UV stabilizer.

6. The electrochromic device according to claim 5, where the device is gray-scale controllable by applying a potential difference of between 0.2 and 1.4 volts to the variable transmittance component.

7. An electrochromic device, comprising a variable transmittance component, where said electrochromic device provides continuously variable transmittance over a range of transmittance as a function of a potential difference applied, and wherein the electrochromic device comprises a UV stabilizer.

8. The electrochromic device according to claim 7, wherein the electrochromic device further comprises one of an acrylic material, a gel and a thickening material.

9. The electrochromic device according to claim 7, wherein the sheet resistance of a transparent electrode layer of the electrochromic device is less than 40 ohms per square.

10. An electrochromic device, comprising a variable transmittance component, where said electrochromic device provides continuously variable transmittance over a range of transmittance as a function of a potential difference applied, and wherein the sheet resistance of a transparent electrode layer of the electrochromic device is less than 40 ohms per square.

12. An electrochromic device, comprising a variable transmittance component, where said electrochromic device provides continuously variable transmittance over a range of transmittance as a function of a potential difference applied, where the current flow during normal device operation is 20 milliamperes per square centimeter or less, and wherein the continuously variable transmittance component comprises a gel and a UV stabilizer.