UV-protected electrochromic solution

• US 6,545,793 B2
• Filed: 01/03/2002
• Issued: 04/08/2003
• Est. Priority Date: 08/18/1997
• Status: Expired due to Fees

• Current Assignee: Bayer AG
• Original Assignee: Bayer AG
• Inventors: Heuer, Helmut-Werner, Neigl, Ralf, Berneth, Horst
• Primary Examiner(s): Schwartz, Jordan M.
• Assistant Examiner(s): STULTZ, JESSICA T
• Application Number:
  US10/037,398
• Publication Number:
  US 20020145790A1
• Time in Patent Office: 460 Days
• Field of Search: 359/265-75, 345/49, 345/105, 252/582, 252/583, 252/586, 348/817
• US Class Current: 359/265
• CPC Class Codes: C07C 49/83 polycyclic
• CPC Class Codes: C07C 49/84 containing ether groups, groups, groups, or groups
• CPC Class Codes: C09K 15/06 containing oxygen
• CPC Class Codes: C09K 15/20 containing nitrogen and oxygen
• 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
• CPC Class Codes: Y10T 428/23 Sheet including cover or casing
• CPC Class Codes: Y10T 428/239 Complete cover or casing
• CPC Class Codes: Y10T 428/249995 Constituent is in liquid form
• CPC Class Codes: Y10T 428/249997 Encapsulated liquid
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]

Abstract

This invention relates to electrochromic devices containing UV-protected electrochromic solutions comprising at least one oxidizable substance RED₁ and at least one reducible substance OX₂ linked by a bridging group and a UV absorber component.

Claims

1. A method for providing variable transmission in an electrochromic device comprising introducing into an electrochromic device a UV-protected electrochromic solution comprising

(a) an electrochromic redox component comprising a weakly colored or colorless combination of at least one oxidizable substance RED₁ that releases electrons at an anode and in so doing undergoes transition into a substance OX₁ and at least one reducible substance OX₂ that accepts electrons at a cathode and in so doing undergoes transition into a substance RED₂, wherein at least one of OX₁ or RED₂ is accompanied by an increase in the absorbance in the visible region of the spectrum and thereby becomes colored and the combination is restored to the weakly colored or colorless form after charge equalization,

with the proviso that at least one of the substances RED₁ is linked covalently to at least one of the substances OX₂ by a bridge;

and

(b) at least one UV absorber selected from the group consisting of unsubstituted and substituted cinnamic esters and unsubstituted and substituted 2-hydroxy-benzophenones.

2. An electrochromic device containing a variable transmission medium comprising a UV-protected electrochromic solution comprising

(a) an electrochromic redox component comprising a weakly colored or colorless combination of at least one oxidizable substance RED₁ that releases electrons at an anode and in so doing undergoes transition into a substance OX, and at least one reducible substance OX₂ that accepts electrons at a cathode and in so doing undergoes transition into a substance RED₂, wherein at least one of OX₁ or RED₂ is accompanied by an increase in the absorbance in the visible region of the spectrum and thereby becomes colored and the combination is restored to the weakly colored or colorless form after charge equalization,

with the proviso that at least one of the substances RED₁ is linked covalently to at least one of the substances OX₂ by a bridge;

and

(b) at least one UV absorber selected from the group consisting of unsubstituted and substituted cinnamic esters and unsubstituted and substituted 2-hydroxy-benzophenones.

3. An electrochromic device according to claim 2 configured as a cell, a window pane, a mirror, a sunroof, or a display device having electrically separate segments with individual electrical contacts.

4. An electrochromic device according to claim 2 consisting of two facing transparent glass or plastic plates in which the facing sides carry an electroconductive coating and between which is contained a UV-protected electrochromic solution comprising

(a) an electrochromic redox component comprising a weakly colored or colorless combination of at least one oxidizable substance RED₁ that releases electrons at an anode and in so doing undergoes transition into a substance OX₁ and at least one reducible substance OX₂ that accepts electrons at a cathode and in so doing undergoes transition into a substance RED₂, wherein at least one of OX₁ or RED₂ is accompanied by an increase in the absorbance in the visible region of the spectrum and thereby becomes colored and the combination is restored to the weakly colored or colorless form after charge equalization,

with the proviso that at least one of the substances RED₁ is linked covalently to at least one of the substances OX₂ by a bridge; and

(b) at least one UV absorber selected from the group consisting of unsubstituted and substituted cinnamic esters and unsubstituted and substituted 2-hydroxy-benzophenOnes.

5. An electrochrOmiC device according to claim 4 wherein one of the plates is mirrored.

6. An electrochromiC device according to claim 4 if that is subdivided into electrically separate segments, each of which contains the electrochromic solution.