Electrochromic display and method for making same
First Claim
1. A process for making an electrochromic display comprising the steps of:
- (a) providing a front substrate having transparent electrodes and image-forming electrochromic layers thereon;
(b) providing a rear substrate for carrying a counter electrode, the front and rear substrates being positioned in spaced working relation;
(c) forming a counter electrode on said rear substrate by1. forming a layer of tungsten trioxide on said substrate;
2. converting a major portion of said tungsten trioxide layer to alkali tungstate to provide a first mixture of alkali tungstate and tungsten trioxide;
3. heating the first mixture to a sufficiently high temperature for a selected time to form a second mixture comprising a major portion of alkali tungsten bronze and a controlled minor portion of tungsten trioxide, the alkali tungsten bronze being in the high temperature heat treated condition which exhibits high electronic mobility for counter electrode purposes;
(d) filling the space between the substrates with electrolyte containing sufficient cationic coloring centers to impart coloration to said electrochromic layers; and
(e) sealing the front and rear substrates together.
1 Assignment
0 Petitions
Accused Products
Abstract
Disclosed is an electrochromic display having an electrolyte of optimized cationic mobility and a counter electrode of optimized electronic mobility. Preferably the display comprises (a) a front substrate with selectively actuable transparent electrodes and image-forming electrochromic layers thereon, (b) an acidified aqueous electrolyte containing a sufficient quantity of highly mobile hydrogen ions for coloration of the electrochromic layers and (c) a rear substrate spaced from the front substrate carrying a counter electrode in contact with the electrolyte, the counter electrode being in the form of a layer comprising predominantly an alkali tungsten bronze, preferably sodium and or potassium tungsten bronze, in the high temperature heat treated condition which exhibits enhanced electronic mobility. A process for making the display is also disclosed.
7 Citations
32 Claims
-
1. A process for making an electrochromic display comprising the steps of:
-
(a) providing a front substrate having transparent electrodes and image-forming electrochromic layers thereon; (b) providing a rear substrate for carrying a counter electrode, the front and rear substrates being positioned in spaced working relation; (c) forming a counter electrode on said rear substrate by 1. forming a layer of tungsten trioxide on said substrate; 2. converting a major portion of said tungsten trioxide layer to alkali tungstate to provide a first mixture of alkali tungstate and tungsten trioxide; 3. heating the first mixture to a sufficiently high temperature for a selected time to form a second mixture comprising a major portion of alkali tungsten bronze and a controlled minor portion of tungsten trioxide, the alkali tungsten bronze being in the high temperature heat treated condition which exhibits high electronic mobility for counter electrode purposes; (d) filling the space between the substrates with electrolyte containing sufficient cationic coloring centers to impart coloration to said electrochromic layers; and (e) sealing the front and rear substrates together. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. In making a counter electrode useful in electrochromic displays, the steps of:
-
(a) forming a layer of tungsten trioxide by vacuum deposition on a substrate; (b) converting a major portion of said tungsten trioxide layer to alkali tungstate to provide a first surface mixture of alkali tungstate and tungsten trioxide; (c) heating the first mixture to a sufficiently high temperature for a selected time to form a second mixture comprising a major portion of alkali tungsten bronze and a controlled minor portion of tungsten trioxide, the alkali tungsten bronze being in the high temperature heat treated condition which exhibits high electronic mobility for counter electrode purposes. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
-
-
19. In making a counter electrode useful in electrochromic displays, the steps of:
-
(a) forming a layer of tungsten trioxide by surface oxidizing a tungsten substrate; (b) converting a major portion of said tungsten trioxide layer to alkali tungstate to provide a first surface mixture of alkali tungstate and tungsten trioxide; (c) heating the first mixture to a sufficiently high temperature for a selected time to form a second mixture comprising a major portion of alkali tungsten bronze and a controlled minor portion of tungsten trioxide, the alkali tungsten bronze being in the high temperature heat treated condition which exhibits high electronic mobility for counter electrode purposes. - View Dependent Claims (20, 21, 22, 23, 24)
-
-
25. An electrochromic display of sandwich construction, comprising:
-
(a) a front substrate with selectively actuable transparent electrodes and image-forming electrochromic layers thereon; (b) an electrolyte having sufficient cationic coloring centers therein to impart coloration to said layers when the display is actuated; (c) a rear substrate spaced from the front substrate for carrying a counter electrode layer in contact with the electrolyte, said counter electrode layer comprising a major portion of high temperature heat treated alkali tungsten broze and a controlled minor portion of tungsten trioxide, said heat treated alkali tungsten bronze functioning as a highly mobile electronic center during actuation of the display. - View Dependent Claims (26, 27, 28, 29)
-
-
30. An electrochromic display of sandwich construction, comprising:
-
(a) a front substrate with selectively actuable transparent electrodes and image forming electrochromic layers thereon; (b) an acidified aqueous electrolyte having sufficient hydrogen ion coloring centers therein to impart coloration to said electrochromic layers when the display is actuated; (c) a rear substrate spaced from the front substrate for carrying a counter electrode layer in contact with the electrolyte, said counter electrode layer comprising alkali tungsten bronze in the high temperature heat treated condition which exhibits high electronic mobility for counter electrode purposes. - View Dependent Claims (31, 32)
-
Specification