Electrochromic device

Information storage and display apparatus comprising as an information storage and display medium an electrochromic device comprising:

• a first electrode including a layer of a transparent electrically conducting material;
• a layer of an electrochromic material including a metal-sensitive compound which is capable of dissolving metal atoms and which changes color in so doing;
• a layer of solid electrolyte, the solid electrolyte being a fast ion conductor in which a fast ion is an ion of the metal which dissolves in the metal-sensitive compound to change the colour thereof, the layer of metal-sensitive compound being in contact with the first electrode and being in contact with the fast ion conductor;
• a second electrode, the second electrode being in contact with said fast ion conductor and being capable of providing and accepting ions the same as said fast ions of the fast ion conductor, in which the mobility of the fast ions or corresponding atoms in at least one of said electrolyte, said second electrode and said electrochromic layer, is or are temperature dependent, there being substantially no mobility at room temperature but the mobility increasing substantially with increase of temperature, whereby the device may be written into or erased by application of a potential difference across the two electrodes at a substantially raised temperature, the display being stable and non-changeable by application of similar potential differences at room temperature, and in which said first electrode and said second electrode each extend over a substantial display area of the device on which display area information is to be written, and both electrodes are provided with electrical contacts for applying a general electrical potential difference across the first electrochromic layer and the solid electrolyte layer over the whole display area of the device, the arrangement of the device being such that information can be written at different locations within said display area by localized heating of the device during application of the general potential difference over the whole display area and comprising as means for writing information into or erasing information from said device;
• an enclosure;
• an aperture allowing insertion of the device into the enclosure;
• and
• means for applying a general electrical potential difference across the device over the whole of the display area of the device, and means for selectively applying heat to individual locations in the display area.

Information storage and display apparatus comprising as an information storage and display medium an electrochromic device comprising:

• a first electrode including a layer of a transparent electrically conducting material;
• a layer of an electrochromic material including a metal-sensitive compound which is capable of dissolving metal atoms and which changes color in so doing;
• a layer of solid electrolyte, the solid electrolyte being a fast ion conductor in which a fast ion is an ion of the metal which dissolves in the metal-sensitive compound to change the color thereof, the layer of metal-sensitive compound being in contact with the first electrode and being in contact with the fast ion conductor;
• a second electrode, the second electrode being in contact with said fast ion conductor and being capable of providing and accepting ions the same as the said fast ions of the fast ion conductor, in which the mobility of the fast ions or corresponding atoms in at least one of said electrolyte, said second electrode and said electrochromic layer, is or are temperature dependent, there being substantially no mobility at room temperature but the mobility increasing substantially with increase of temperature whereby the device may be written into or erased by application of a potential difference across the two electrodes at a substantially raised temperature, the display being stable and non-changeable by application of similar potential differences at room temperature, and in which the device has a display area on which information is to be displayed, and there are provided a plurality of electrical contacts leading to different locations within the display area, whereby different required potentials can be applied to different selected locations of the display area during an overall heating of the whole display are, to effect writing and erasing of information in the diaplay area, and comprising as means for writing information into or erasing information from said device;
• an enclosure;
• an aperture allowing insertion of the display device into the enclosure;
• and
• means for applying a general, overall heating effect over the whole of a display area of the device, and means for selectively applying a potential difference across the device at individual locations in the display area.