Electrochromic device with two thin glass elements and a gelled electrochromic medium

• US 6,545,794 B2
• Filed: 12/23/2000
• Issued: 04/08/2003
• Est. Priority Date: 04/02/1997
• Status: Expired due to Term

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Ash, Kevin L., Tonar, William L., Bauer, Frederick T., Theiste, David A., Roberts, Kathy E.
• Primary Examiner(s): Dang, Hung Xuan
• Assistant Examiner(s): TRA, TUYEN Q
• Application Number:
  US09/745,639
• Publication Number:
  US 20010005274A1
• Time in Patent Office: 836 Days
• Field of Search: 359/265, 359/266, 359/267, 359/270, 359/273, 359/274, 252/582, 252/583
• US Class Current: 359/270
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• 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: G02F 1/161 Gaskets; Spacers; Sealing of cells; Filling or closing of cells
• 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

An electrochromic device comprising: a first glass element having an electrically conductive material associated therewith, wherein said first element comprises a height (h₁), a width (w₁), a thickness (t₁), an inner surface, and an outer surface; a second element having an electrically conductive material associated therewith, wherein said second element comprises a height (h₂), a width (w₂) , and a thickness (t₂), an inner surface, and an outer surface; a cell spacing (c) which comprises a distance between said inner surface of said first element and said inner surface of said second element; a gelled electrochromic medium contained within a chamber positioned between said first and second elements; wherein (h₁), (w₁), (t₁), (h₂), (w₂), (t₂), and (c) are numerical values in millimeters; and wherein (h₁), (w₁), and (t₁) of said first element, and (h₂), (w₂), and (t₂) of said second element and (c) comprise numerical values such that the following inequality is satisfied: $\frac{2h_1^5\left(1-{}^{-2^{{\left(h_1/w_1\right)}^2}}\right)}{t_1^3\left(7.57\times {10}^{12}\right)}+\frac{2h_2^5\left(1-{}^{-2^{{\left(h_2/w_2\right)}^2}}\right)}{t_2^3\left(7.57\times {10}^{12}\right)}\ge \mathrm{.1}\left(c\right).$

Claims

1. An electrochromic device, comprising:

a first glass element having an electrically conductive material associated therewith, wherein said first element comprises a height (h₁) , a width (w₁) , a thickness (t₁), an inner surface, and an outer surface;

a second glass element having an electrically conductive material associated therewith, wherein said second element comprises a height (h₂) , a width (w₂), and a thickness (t₂), an inner surface, and an outer surface;

a cell spacing (c) which comprises a distance between said inner surface of said first element and said inner surface of said second element;

a gelled electrochromic medium contained within a chamber positioned between said first and second elements;

wherein (h₁), (w₁), (t₁), (h₂), (w₂), (t₂), and (c) are numerical values in millimeters, wherein (t₁) and (t₂) having thickness of at least 0.5 mm; and

wherein (h₁), (w₁), and (t₁) of said first element, and (h₂), (w₂), and (t₂) of said second element and (c) comprise numerical values such that the following inequality is satisfied;

$\frac{2<br><br>h_1^5<br><br>\left(1-{\mathrm{<br><br>}}^{-2^{{\left(h_1/w_1\right)}^2}}\right)}{t_1^3<br><br>\left(7.57\times <br><br>{10}^{12}\right)}+\frac{2<br><br>h_2^5<br><br>\left(1-{\mathrm{<br><br>}}^{-2^{{\left(h_2/w_2\right)}^2}}\right)}{t_2^3<br><br>\left(7.57\times <br><br>{10}^{12}\right)}\ge <br><br>\mathrm{.1}<br><br>\left(c\right).$

2. The electrochromic device according to claim 1, wherein said first and second elements are substantially linear.

3. The electrochromic device according to claim 1, wherein said first and second elements are bent to a convex shape.

4. The electrochromic device according to claim 1, wherein said first and second elements are bent to an aspheric shape.

5. The electrochromic device according to claim 1, wherein said gelled electrochromic medium comprises a crosslinked polymer matrix.

6. An electrochromic device, comprising:

a first glass element having an electrically conductive material associated therewith, wherein said first element comprises a height (h₁), a width (w₁), a thickness (t₁), an inner surface, and an outer surface;

a second glass element having an electrically conductive material associated therewith, wherein said second element comprises a height (h₂) , a width (w₂) , and a thickness (t₂), an inner surface, and an outer surface;

a cell spacing (c) which comprises a distance between said inner surface of said first element and said inner surface of said second element;

a gelled electrochromic medium contained within a chamber positioned between said first and second elements;

wherein (h₁), (w₁), (t₁), (h₂), (w₂), (t₂), and (c) are independent numerical values in millimeters, wherein (t₁) and (t₂) having thickness of at least 0.5 mm; and

wherein (h₁), (w₁), and (t₁) of said first element, and (h₂), (w₂), and (t₂) of said second element and (c) comprise numerical values such that the following inequality is satisfied;

$\frac{2<br><br>h_1^5<br><br>\left(1-{\mathrm{<br><br>}}^{-2^{{\left(h_1/w_1\right)}^2}}\right)}{t_1^3<br><br>\left(7.57\times <br><br>{10}^{12}\right)}+\frac{2<br><br>h_2^5<br><br>\left(1-{\mathrm{<br><br>}}^{-2^{{\left(h_2/w_2\right)}^2}}\right)}{t_2^3<br><br>\left(7.57\times <br><br>{10}^{12}\right)}\approx <br><br>0.1<br><br>\left(c\right).$

7. The electrochromic device according to claim 6, wherein said first and second elements are substantially linear.

8. The electrochromic device according to claim 6, wherein said first and second elements are bent to a convex shape.

9. The electrochromic device according to claim 6, wherein said first and second elements are bent to an aspheric shape.

10. The electrochromic device according to claim 6, wherein said gelled electrochromic medium comprises a crosslinked polymer matrix.

11. An electrochromic device, comprising:

thin front and rear spaced glass elements, each having front and rear surfaces, wherein said front element comprises a height (h₁), a width (w₁), a thickness (t₁) and said rear element comprises a height (h₂), a width (w₂), and a thickness (t₂);

a layer of transparent conductive material disposed on said rear surface of said front element and on said front surface of said rear element;

a reflector disposed on one side of said rear element provided that, if said reflector is on said rear surface of said rear element, then said front surface of said rear element contains a layer of a transparent conductive material;

a perimeter sealing member bonding together said front and rear spaced elements in a spaced-apart relationship to define a chamber therebetween, where said chamber contains a free-standing gel comprising a solvent and a crosslinked polymer matrix, and wherein said chamber further contains at least one electrochromic material in solution with said solvent and, as part of said solution, interspersed in said crosslinked polymer matrix;

wherein said polymer matrix cooperatively interacts with said front and rear elements to form one thick, strong unitary member, and where said reflector is effective to reflect light through said chamber and said front element when said light reaches said reflector after passing through said front element and said chamber;

a cell spacing (c) which comprises a distance between said rear surface of said front element and said front surface of said rear element;

wherein (h₁), (w₁), (t₁), (h₂), (w₂), (t₂), and (c) are numerical values in millimeters, wherein (t₁) and (t₂) having thickness of at least 0.5 mm; and

wherein (h₁), (w₁), and (t₁) of said first element, and (h₂), (w₂), and (t₂) of said second element and (c) comprise numerical values such that the following inequality is satisfied;

$\frac{2<br><br>h_1^5<br><br>\left(1-{\mathrm{<br><br>}}^{-2^{{\left(h_1/w_1\right)}^2}}\right)}{t_1^3<br><br>\left(7.57\times <br><br>{10}^{12}\right)}+\frac{2<br><br>h_2^5<br><br>\left(1-{\mathrm{<br><br>}}^{-2^{{\left(h_2/w_2\right)}^2}}\right)}{t_2^3<br><br>\left(7.57\times <br><br>{10}^{12}\right)}\ge <br><br>0.1<br><br>\left(c\right).$

12. The electrochromic device according to claim 11, wherein said first and second elements are substantially linear.

13. The electrochromic device according to claim 11, wherein said first and second elements are bent to a convex shape.

14. The electrochromic device according to claim 11, wherein said first and second elements are bent to an aspheric shape.

15. The electrochromic device according to claim 11, wherein said polymer matrix results from crosslinking polymer chains and where said polymer chains are formed by polymerizing at least one monomer selected from the group consisting of:

methyl methacrylate;

methyl acrylate;

2-isocyanatoethyl methacrylate;

2-isocyanatoethyl acrylate;

2-hydroxyethyl methacrylate;

2-hydroxyethyl acrylate;

3-hydroxypropyl methacrylate;

vinyl ether n-butyl methyl methacrylate;

tetraethylene glycol vinyl ether;

glycidyl methacrylate;

4-vinylphenol;

acetoacetoxyethyl methacrylate and acetoacetoxyethyl acrylate.

16. The electrochromic device according to claim 15, wherein said polymer chains are cross-linked by reaction with a compound having a functional group selected from the group consisting of aromatic and aliphatic hydroxyl;

aromatic and aliphatic cyanato;

aromatic and aliphatic isocyanato;

aliphatic and aromatic isothiocyanato, with a functionality of at least 2.

17. The electrochromic device according to claim 15, wherein said polymer chains results from the polymerization of at least two distinct monomers.

18. The electrochromic device according to claim 15, wherein said at least two monomers are selected from the group consisting of:

methyl methacrylate;

methyl acrylate;

2-isocyanatoethyl methacrylate;

2-isocyanatoethyl acrylate;

2-hydroxyethyl methacrylate;

2-hydroxyethyl acrylate;

3-hydroxypropyl methacrylate;

vinyl ether n-butyl methyl methacrylate;

tetraethylene glycol divinyl ether;

glycidyl methacrylate;

4-vinylphenol;

acetoacetoxyethyl methacrylate and acetoacetoxyethyl acrylate.

19. The electrochromic device according to claim 18, wherein said at least two monomers are selected from the group consisting of:

methyl methacrylate;

2-isocyanatoethyl methacrylate;

2-hydroxyethyl methacrylate; and

glycidyl methacrylate.

20. The electrochromic device according to claim 19, wherein said at least two monomers comprise 2-hydroxyethyl methacrylate and methyl methacrylate.

21. The electrochromic device according to claim 20, wherein the ratio of 2-hydroxyethyl methacrylate to methyl methacrylate is about 1:

10.

22. The electrochromic device according to claim 20, wherein said polymer chains formed from at least 2-hydroxyethyl methacrylate and methyl methacrylate are crosslinked by a compound having more than one functional group that will react with an active hydrogen.

23. The electrochromic device according to claim 19, wherein said at least two monomers comprise isocyanatoethyl methacrylate and methyl methacrylate.

24. The electrochromic device according to claim 23, wherein the ratio of isocyanatoethyl methacrylate to methyl methacrylate ranges from about 1:

3 to about 1;

50.

25. The electrochromic device according to claim 24, wherein the ratio of isocyanatoethyl methacrylate to methyl methacrylate is about 1:

20.

26. The electrochromic device according to claim 24, wherein said polymer chains formed from at least isocyanatoethyl methacrylate and methyl methacrylate are crosslinked by a compound having a functional group containing more than one active hydrogen.

27. The electrochromic device according to claim 15, wherein said polymer matrix is formed from at least two distinct polymer chains, each of said at least two distinct polymer chains comprise at least one monomer selected from the group consisting of methyl methacrylate and methyl acrylate polymerized with at least one monomer selected from the group consisting of 2-isocyanatoethyl methacrylate;

2-isocyanatoethyl acrylate;

2-hydroxyethyl methacrylate;

2-hydroxyethyl acrylate;

3-hydroxypropyl methacrylate;

glycidyl methacrylate;

4-vinylphenol;

acetoacetoxyethyl methacrylate;

vinyl ether n-butyl methyl methacrylate and acetoacetoxyethyl acrylate, where said first and second polymer chains may be the same or different.

28. The electrochromic device according to claim 27, wherein said first of said at least two polymer chains comprises a copolymer of isocyanatoethyl methacrylate and methyl methacrylate and where said second of said at least two polymer chains comprises a copolymer of 2-hydroxyethyl methacrylate and methyl methacrylate.

29. The electrochromic device according to claim 28, wherein where the ratio of isocyanatoethyl methacrylate and methyl methacrylate ranges from about 1:

3 to about 1;

50 and where the ratio of 2-hydroxyethyl methacrylate and methyl methacrylate ranges from about 1;

3 to about 1;

50.

30. The electrochromic device according to claim 11, wherein said cooperative interaction between said free standing gel and said front and rear elements makes said device resistant to bending and breaking.

31. The electrochromic device according to claim 11, further comprising polymeric beads disposed within said chamber.

32. The electrochromic device according to claim 31, wherein said beads comprise a material that will dissolve within an electrochromic device at ambient or near-ambient temperatures within about 24 hours.

33. The electrochromic device according to claim 32, wherein said beads comprise a copolymer selected from the group consisting of:

MMA/methacrylic acid, MMA/ethylacrylate, MMA/n-butylacrylate, and poly(propylene carbonate).

34. The electrochromic device according to claim 32, wherein said beads do not impart any refractive imperfections to said device.

35. The electrochromic device according to claim 11, wherein said layer of transparent conductive material disposed on said rear surface of said front element is a multi-layer stack having a first layer with a high refractive index, a second layer with a low refractive index and a third layer with a high refractive index.