Electrochromic device with nanoparticles and UV-absorbers in the protective coating

• US 7,190,506 B1
• Filed: 02/01/2000
• Issued: 03/13/2007
• Est. Priority Date: 02/12/1999
• Status: Expired due to Fees

• Current Assignee: Bayer AG
• Original Assignee: Bayer AG
• Inventors: Hoheisel, Werner, Womelsdorf, Hermann, Neigl, Ralf, Berneth, Horst
• Primary Examiner(s): Lester; Evelyn A.
• Application Number:
  US09/913,133
• Time in Patent Office: 2,597 Days
• Field of Search: 359265-275, 252/583, 252/586, 252/600
• US Class Current: 359/274
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: E06B 9/24 Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; Slat blindsoperating, guiding or securing devices or arrangements for roll-type closures E06B9/56; free-hanging flexible screens A47H23/00
• 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 2001/1536 additional, e.g. protective, layer inside the cell
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials

Abstract

An electrochromic device which carries a coating comprising at least one UV absorber and nanoparticles is effectively protected against destruction by UV light.

Claims

1. An electrochromic device consisting of a pair of glass or plastic plates or plastic films of which at least one plate or film are provided on in each case one side with an electrically conductive coating, of which at least one plate or film and its conductive coating is transparent, of which the other, optionally, is mirrored, and of which in the case of at least one of the two plates or films the electrically conductive layer is optionally, divided into separate, individually contacted area segments, where the plates or films are joined together via a sealing ring on the sides of their conductive coating, and the volume formed by the two plates or films and the sealing ring is filled with an electrochromic medium, wherein at least one of the two plates or films carries a coating which comprises nanoparticles and at least one UV absorber.

2. The electrochromic device as claimed in claim 1, wherein the at least one UV absorber of said coating comprises an organic UV absorber.

3. The electrochromic device as claimed in claim 1, wherein the coating comprises an organic UV absorber and inorganic nanoparticles.

4. The electrochromic device as claimed in claim 1, wherein the absorption edge of the nanoparticles is at a shorter wavelength than the long-wave absorption edge of the UV absorber.

5. The electrochromic device as claimed in claim 1, wherein it is a display device.

6. The electrochromic device as claimed claim 1, wherein it is a mirror.

7. The electrochromic device as claimed in claim 1, wherein it is a window.

8. The electrochromic device as claimed in claim 1, wherein the coating consists of an organic polymer.

9. The electrochromic device as claimed in claim 1, wherein the electrochromic medium comprises at least one pair of redox substances, one of which is reducible and the other is oxidizable, both being colorless or only weakly colored, and, after application of a voltage to the electrochromic device, the first substance is reduced and the other is oxidized, at least one becoming colored, and, after the voltage is switched off, the two original redox substances are reformed and the electrochromic device decolorizes.

10. The electrochromic device as claimed in claim 9, wherein

a) the reducible substance has at least one chemically reversible reduction waves in the cyclic voltammogram and the oxidizable substance correspondingly has at least one chemically reversible oxidation waves, or

b) the reducible substance and the oxidizable substance are covalently bonded to one another via a bridge B, or

c) the reducible and/or oxidizable substances selected are those in which the reversible transition between the oxidizable form and the reducible form or vice versa is associated with the breaking or forming of a σ

-bond, or

d) the reducible substance and/or the oxidizable substance are metal salts or metal complexes of metals which exist in at least two oxidation states, or

e) the reducible and/or oxidizable substances are oligomers and polymers containing at least one of said redox systems, but also pairs of such redox systems as defined under a) to d), or

f) the reducible and/or oxidizable substances employed are mixtures of the substances described in a) to e), provided that these mixtures contain at least one reducible and at least one oxidizable redox system.

11. The electrochromic device as claimed in claim 1, wherein the organic UV absorber used is at least one of the formulae

12. The electrochromic device as claimed in claim 3, wherein the inorganic nanoparticles are those based on SiC, AlSi, Ag, Fe₂O₃, Fe₃O₄, TiO₂, ZnO, GaP, CeO₂, ZnS, SnO₂, Si_yGe_1-y, W_xMo_1-xO₃, NiO, Bi₂O₃, In₂O₃, HfO₂, BaTiO₃, CaTiO₃, Ge, AlP, GaN, in which 0.7≦

y<

1 and 0≦

x≦

1.

13. An electrochromic device according to claim 1, wherein both plates or films are provided on in each case one side with an electrically conductive coating.

14. The electrochromic device as claimed in claim 9, wherein the reducible substance has at least two chemically reversible reduction waves in the cyclic voltammogram and the oxidizable substance correspondingly has at least two chemically reversible oxidation waves.