Display device
First Claim
Patent Images
1. A passive matrix display device, comprising:
- a set of pixel cells arranged in a matrix,wherein each of the pixel cells includes,a first pixel layer including an electronically conducting electrochromic and electrochemically active organic polymer material being electrochemically switchable between different visually detectable coloring states,a second pixel layer facing said first pixel layer, anda third pixel layer of solidified electrolyte, said solidified electrolyte being a polycationic or polyanionic electrolyte, wherein said third pixel layer is arranged spatially between, and in ionic contact with, said first and second pixel layers, and said third pixel layer is free of electrochromic material,wherein the coloring of each pixel cell is provided by a change in redox state of said electrochromic and electrochemically active organic polymer material of said first pixel layer, and the color of the third pixel layer remains unchanged during a color switching of the pixel,wherein said second pixel layer of each of said pixel cells is formed of a material including electrically conductive carbon, which in combination with the materials in the first and third pixel layers in all pixel cells provides a threshold voltage at least in response to a potential difference applied across said pixel cell, andwherein the potential difference is set so that a sum of potential differences distributed in a non-addressed cell by cross-talk from addressed pixel cells is lower than the threshold voltage of the pixel cell.
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Abstract
There is disclosed an electrochromic passive-matrix display, wherein each passively addressed pixel cell comprises an electrolyte ionically connecting an electrochromic and electrochemically active polymer and a layer of electrically conducting carbon. Thus, each pixel has a pronounced threshold voltage sufficient for reducing cross talk in an electrochromic display.
32 Citations
22 Claims
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1. A passive matrix display device, comprising:
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a set of pixel cells arranged in a matrix, wherein each of the pixel cells includes, a first pixel layer including an electronically conducting electrochromic and electrochemically active organic polymer material being electrochemically switchable between different visually detectable coloring states, a second pixel layer facing said first pixel layer, and a third pixel layer of solidified electrolyte, said solidified electrolyte being a polycationic or polyanionic electrolyte, wherein said third pixel layer is arranged spatially between, and in ionic contact with, said first and second pixel layers, and said third pixel layer is free of electrochromic material, wherein the coloring of each pixel cell is provided by a change in redox state of said electrochromic and electrochemically active organic polymer material of said first pixel layer, and the color of the third pixel layer remains unchanged during a color switching of the pixel, wherein said second pixel layer of each of said pixel cells is formed of a material including electrically conductive carbon, which in combination with the materials in the first and third pixel layers in all pixel cells provides a threshold voltage at least in response to a potential difference applied across said pixel cell, and wherein the potential difference is set so that a sum of potential differences distributed in a non-addressed cell by cross-talk from addressed pixel cells is lower than the threshold voltage of the pixel cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of controlling a passive matrix display device including a set of pixel cells arranged in a matrix, wherein each pixel cell includes,
a first pixel layer including an electronically conducting electrochromic and electrochemically active organic polymer material being electrochemically switchable between different visually detectable coloring states, a second pixel layer facing said first pixel layer, and a third pixel layer of solidified electrolyte, said solidified electrolyte being a polycationic or polyanionic electrolyte, wherein said third pixel layer is arranged spatially between, and in ionic contact with, said first and second pixel layers, and said third pixel layer is free of electrochromic material, the method comprising: -
applying and maintaining a potential difference between said first pixel layer and said second pixel layer, wherein said potential difference causes said first pixel layer to change color, wherein the coloring of each pixel cell is provided by a change in redox state of said electrochromic and electrochemically active organic polymer material of said first pixel layer, and the color of the third pixel layer remains unchanged during a color switching of the pixel, wherein said second pixel layer of each of the pixel cells is formed of, or includes, electrically conductive carbon, which in combination with the materials in the first and third pixel layers in all pixel cells provides a threshold voltage at least in response to a potential difference applied across said pixel cell, and wherein the potential difference is set so that a sum of potential differences distributed in a non-addressed cell by cross-talk from addressed pixel cells is lower than the threshold voltage of the pixel cell.
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21. A passive matrix display device, comprising:
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a set of pixel cells arranged in a matrix, wherein each of the pixel cells includes, a first pixel layer including an electronically conducting electrochromic and electrochemically active organic polymer material being electrochemically switchable between different visually detectable coloring states, a second pixel layer facing said first pixel layer, and a third pixel layer of solidified electrolyte, said solidified electrolyte being a polycationic or polyanionic electrolyte, wherein said third pixel layer is arranged spatially between, and in ionic contact with, said first and second pixel layers, and said third pixel layer is free of electrochromic material, wherein; said third pixel layer is patterned so as to form discontinuous islands, wherein each island is confined to one pixel cell, the coloring of each pixel cell is provided by a change in redox state of said electrochromic and electrochemically active organic polymer material of said first pixel layer, and the color of the third pixel layer remains unchanged during a color switching of the pixel, and said second pixel layer of each of said pixel cells is formed of a material including electrically conductive carbon, which in combination with the materials in the first and third pixel layers in all pixel cells provides a threshold voltage at least in response to a potential difference applied across said pixel cell, and wherein the potential difference is set so that a sum of potential differences distributed in a non-addressed cell by cross-talk from addressed pixel cells is lower than the threshold voltage of the pixel cell.
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22. A passive matrix display device, comprising:
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a set of first electrodes, each of the first electrodes includes an electrochromic and electrochemically active organic polymer material that is electrochemically switchable between different visually detectable coloring states; and a set of second electrodes, wherein the set of first electrodes and the set of second electrodes are electronically isolated from each other and arranged such that each of the first electrodes intersects each of the second electrodes at only one intersection, and at each intersection there is arranged a pixel cell, and the pixel cells are arranged in a matrix, wherein each pixel cell includes; a first pixel layer which is the portion of the respective first electrode located at the intersection; a second pixel layer facing the first pixel layer, and a third pixel layer of solidified electrolyte which is arranged spatially between, and in ionic contact with, the first and second pixel layers, wherein the second pixel layer of each pixel cell is formed of a material including electrically conductive carbon, and the solidified electrolyte is a polycationic electrolyte or a polyanionic electrolyte, thereby providing a threshold voltage in response to a potential difference applied across the pixel cell, wherein the coloring of each pixel cell is provided by a change In redox state of the electrochromic and electrochemically active organic polymer material, and the color of the electrolyte remains unchanged during a color switching of the pixel cell, wherein the second pixel layer of each pixel cell is either the portion of the respective second electrode located at the intersection, or a separate layer in electronic contact with the respective second electrode at the intersection, and wherein the potential difference is set so that a sum of potential differences distributed in a non-addressed cell by cross-talk from addressed pixel cells is lower than the threshold voltage of the pixel cell.
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Specification