Electrochromic display

• US 4,139,275 A
• Filed: 03/02/1977
• Issued: 02/13/1979
• Est. Priority Date: 03/02/1976
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Uede, Hisashi, Yano, Kozo, Inami, Yasuhiko
• Primary Examiner(s): Padgett, Benjamin R.
• Assistant Examiner(s): Gron, T. S.
• Application Number:
  US05/773,774
• Time in Patent Office: 713 Days
• Field of Search: 252/500, 252/518, 252/408, 350/357
• US Class Current: 359/270
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1525 characterised by a particular ion transporting layer, e.g. electrolyte

Abstract

In an electro-optic display which utilizes the electrochromism phenomenon of a transition metal oxide, an organic solvent for an electrolyte in contact with the transition metal oxide comprises at least one member selected from the group consisting of ketones represented by the chemical formula of C_n H_2n+1 COC_m H_2m+1 wherein n = 1, 2 and m = 2 ˜ 4; alkyl acetates represented by the chemical formula of CH₃ COOC_n H_2n+1 wherein n = 2, 3; ethylene glycol monoalkoxy acetates represented by the chemical formula of CH₃ COOCH₂ CH₂ OC_n H_2n+1 wherein n = 1, 2; and diethylene glycol monoalkoxy acetates represented by the chemical formula of CH₃ COOCH₂ CH₂ OCH₂ CH₂ OC_n H_2n+1 wherein n = 1 ˜ 4.

Claims

1. An electrochromic display comprising an electrochromic transition metal oxide said electrochromic display deposited on a transparent display electrode, and a counter electrode, containing an electrolyte in solution in an organic solvent, which solution is in contact with the transition metal oxide, said organic solvent comprising at least one member selected from the group consisting of ketones represented by the chemical formula C_n H_2n+1 COC_m H_2m+1 wherein n = 1, 2 and m = 2 ˜

4;

alkyl acetates represented by the chemical formula of CH₃ COOC_m H_2m+1 wherein m = 2, 3;

ethylene glycol monoalkoxy acetates represented by the chemical formula of CH₃ COOCH₂ CH₂ OC_n H_2n+1 wherein n = 1, 2; and

diethylene glycol monoalkoxy acetates represented by the chemical formula of CH₃ COOCH₂ CH₂ OCH₂ CH₂ OC_n H_2n+1 wherein n = 1 ˜

4.

2. An electrochromic display as defined in claim 1 wherein the transition metal oxide is tungsten oxide.

3. The electrochromic display as defined in claim 1 wherein the transition metal oxide deposited on the transparent display electrode comprises tungsten oxide deposited on an indium oxide film and the counter electrode comprises a transparent film of indium oxide.

4. A reflective electrochromic display cell comprising an electrochromic transition metal oxide deposited on a transparent display electrode, and a counter electrode, said electrodes defining therebetween reflective, white background electrolyte paste, said electrolyte paste containing a mixture of an electrolyte in solution in an organic solvent and an inorganic white powder, said organic solvent comprising at least one member selected from the group consisting of ketones represented by the chemical formula of C_n H_2n+1 COC_m H_2m+1 wherein n = 1, 2 and m = 2 ˜

4;

alkyl acetates represented by the chemical formula CH₃ COOC_m H_2m+1 wherein m = 2, 3;

ethylene glycol monoalkoxy acetates represented by the chemical formula of CH₃ COOCH₂ CH₂ OC_n H_2n+1 wherein n = 1, 2; and

diethylene glycol monoalkoxy acetates represented by the chemical formula of CH₃ COOCH₂ CH₂ OCH₂ CH₂ OC_n H_2n+1 wherein n = 1 ˜

4.

5. The reflective electrochromic display cell of claim 4, wherein the electrolyte is lithium perchlorate and the inorganic white powder is barium sulfate.

6. The reflective electrochromic display cell of claim 4, wherein both the electrochromic transition metal oxide deposited on the transparent display electrode and the counter electrode comprise an electrochromic transition metal oxide film deposited on a film of transparent transition metal oxide.

7. The reflective electrochromic display cell of claim 6, wherein both the electrochromic transition metal oxide deposited on the display electrode and the counter electrode comprise a tungsten oxide film deposited on a film of indium oxide.