Electrochromic media for producing a preselected color and devices comprising same

• US 6,661,559 B2
• Filed: 08/02/2001
• Issued: 12/09/2003
• Est. Priority Date: 04/02/1997
• Status: Expired due to Term

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Winkle, Derick D., Guarr, Thomas F., Byker, Harlan J.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/920,686
• Publication Number:
  US 20020051278A1
• Time in Patent Office: 859 Days
• Field of Search: 359/265, 359/272, 359/273, 359/275, 359/321, 359/322, 252/583, 252/600, 546/257, 544/347
• US Class Current: 359/265
• CPC Class Codes: C07D 213/22 containing two or more pyridine rings directly linked together, e.g. bipyridyl
• CPC Class Codes: C07D 241/36 condensed with carbocyclic rings or ring systems
• CPC Class Codes: C07D 241/46 Phenazines
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions

Abstract

Electrochromic compositions suitable for use in electrochromic media in electrochromic devices contain minimally two electrochromic compounds of the same redox type, whose redox potentials are greater than 30 mV. The lower redox potential electrochromic compounds makes a large contribution to the absorbancy of the electrochromic medium despite being present in only minor concentration.

Claims

1. An electrochromic device, comprising:

a first substantially transparent substrate having an electrically conductive material associated therewith;

a second substrate having an electrically conductive material associated therewith; and

an electrochromic medium contained within a chamber positioned between the first and second substrates which comprises;

at least one solvent;

a first electroactive compound;

a second electroactive compound;

a third electroactive compound;

wherein at least two of the first, second, and third electroactive compounds are electrochromic;

wherein at least two of the first, second, and third electroactive compounds are of the same redox type; and

wherein at least two of the first, second, and third electroactive compounds cooperatively interact to, in turn, generate an electrochromic medium having a preselected color.

2. The electrochromic device according to claim 1 wherein the electrochromic medium comprises at least two anodic electroactive compounds and at least one cathodic electroactive compound.

3. The electrochromic device according to claim 1, wherein the electrochromic medium comprises at least two cathodic electroactive compounds and at least one anodic electroactive compound.

4. The electrochromic device according to claim 1, wherein the electrochromic medium does not exhibit staging.

5. An electrochromic device, comprising:

a first substantially transparent substrate having an electrically conductive material associated therewith;

a second substrate having an electrically conductive material associated therewith; and

an electrochromic medium contained within a chamber positioned between the first and second substrates which is capable of producing a preselected color comprising at least three electroactive compounds, two of which are of the same redox type and another which is of a complementary redox type, where one of the two electroactive compounds of the same redox type has a more easily accessible electrochemically activated redox state than the other by minimally 20 mV, and where two of the at least three electroactive compounds are electrochromic.

6. The electrochromic device according to claim 5, wherein the at least three electroactive compounds comprise at least two anodic electroactive compounds and at least one cathodic electroactive compound.

7. The electrochromic device according to claim 5, wherein the at least three electroactive compounds comprise at least two cathodic electroactive compounds and at least one anodic electroactive compound.

8. The electrochromic device according to claim 5, wherein the electroactive compound of the same redox type whose redox state is more easily accessible is present in the amount of 28 mol percent or less of the total electrochromic compounds of the same type.

9. The electrochromic device according to claim 5, wherein the electroactive compound of the same redox type whose redox state is more easily accessible is present in the amount of 25 mol percent or less of the total electrochromic compounds of the same type.

10. The electrochromic device according to claim 5, wherein the electroactive compound of the same redox state is more easily accessible is present in the amount of 20 mol percent or less of the total electrochromic compounds of the same type.

11. The electrochromic device according to claim 5, wherein the electrochromic medium does not exhibit staging.

12. An electrochromic device, comprising:

a first substantially transparent substrate having an electrically conductive material associated therewith;

a second substrate having an electrically conductive material associated therewith; and

an electrochromic medium contained within a chamber positioned between the first and second substrates which comprises;

at least one solvent;

a first electroactive compound;

a second electroactive compound;

a third electroactive compound;

wherein at least two of the first, second, and third electroactive compounds are electrochromic;

wherein at least two of the first, second, and third electroactive compounds are of the same redox type; and

means associated with the medium for controllably preselecting the color of the electrochromic medium with first, second, and third electroactive compounds.