Sharp Kabushiki Kaisha Corporation

Sharp Corporation

Hiroshi Nakauchi

Yasuhiko Inami

Hiroshi Hamada

Hisashi Uede

Tadanori Hishida

Kozo Yano

Hiroaki Kato

Hiroshi Kuwagaki

Sadatoshi Takechi

Katubumi Koyanagi

Yutaka Takafuji

Tomio Wada

Kohzo Yano

A method of driving an electrochromic display device and the electrochromic display device therefor the latter including an electrochromic display cell having two opposed substrates at least one of which is transparent, a plurality of electrodes respectively applied to the opposed substrates and an electrochromic substance held in contact with said plurality of electrodes between said opposed substrates so as to reversibly vary its light absorbing characteristics by an electric current applied to the electrodes, and a driving circuit coupled to the electrochromic display cell for driving the latter, wherein erasing the display of the electrochromic cell is done in such a manner that the erasing current will be stopped eventually by the electrochromic substance itself in order to secure complete erasure.

Method of driving electrochromic display device and electrochromic

A driving technique is provided for an electro-optical display which includes an electrochromic material and a predetermined number of display segments, combinations of the display segments each defining a different one of a desired number display patterns. The electrochromic phenomenon is developed within the electro-optical display upon a flow of current supplied through the display segments. In transition of a visual display from a specific display pattern to another, current is applied to only the one or more display segments which are not common to the two display patterns, while no current is supplied to the one or more display segments common to the two display patterns.

Driving technique for electrochromic displays of the segmented type

A porous separator is provided with an electrochromic display for containing an electrolyte, whereby a display electrode is continuously, electrically rotated to a counter electrode through the electrolyte. A filter separator is further provided together with the porous separator for urging the porous separator toward the display electrode and itself toward the counter electrode because of the elastic characteristic thereof. The filter separator can also contain the electrolyte. The porous separator provides a white background for the display electrode. The remaining electrolyte, except for the electrolyte in both the porous and the filter separators, is eliminated from the electrochromic display to provide a cavity within the electrolyte for cancelling the cubic expansion of the electrolyte when temperature rises. This cubic expansion cancelling cavity may be formed by injecting a bubble into the electrolyte. The cavity is settled at a fixed position by the provision of an electrolyte-impregnated separator means without any interference with the display and counter electrodes.

Electrochromic display with one porous separator

A constant-voltage circuit is interposed between a power source and a driver circuit for an electrochromic display. The constant-voltage circuit functions to compensate for variations of an output level of the power source in order to stabilize coloration and bleaching operations. Switching means are interposed between the power source and the constant-voltage circuit for placing the constant-voltage circuit in an operative condition only when the coloration operation or the bleaching operation is conducted.

Driver circuit for electrochromic displays

In an electrochromic display comprising a back plate electrode, a plurality of display electrodes, and a reference electrode available for maintaining the potential of the respective display electrodes at a fixed value, there is provided a detector for sensing the counter electromotive force which is developed between the display electrodes and the reference electrode in a manner such that there is created a remarkable difference in the output voltage signal thereof between in the colored state and in the bleached state. Therefore, the output signal from the detector indicates whether the electrochromic display is held in the colored state or the bleached state.

Electric memory detector in an ECD driver

A combined constant potential and constant voltage driving technique is utilized which is much more effective to drive an electrochromic display. The electrochromic display manifests the electrochromic phenomenon to place the display in a colored state or a bleached state in response to current applied thereto. A constant potential driving manner is employed in coloring the electrochromic display, while a constant voltage driving manner is employed in bleaching the same.

Combined constant potential and constant voltage driving technique for

Electrochromic display device employed in a liquid EC system in which an electrode and electrochromic material applied thereon are segmented to define segments corresponding to elements of a displaying pattern and electrode segment portions in excess of the area required to define the displaying pattern are coated with an insulator material, excess area portions of electrochromic material also being similarly coated if necessary, whereby there is reduced build-up of reverse EMF upon activation of the cell and longer color persistence is achieved without use of a complicated drive circuit. To simplify device manufacture for mass-production purposes electrochromic material may be applied in a single layer on an electrode and the display pattern is defined by insulator material applied on selected areas of the electrochromic material.

Electrochromic display device

A method of driving an electrochromic display means and the electrochromic display means therefor which includes an electrochromic display cell having a counter electrode and a plurality of display electrodes, and a constant voltage source coupled through switching means to the electrochromic display cell in such a manner that the display electrodes to be colored are maintained at the same potential as that of the counter electrode, while the display electrodes to be erased are impressed with a predetermined positive voltage with respect too the counter electrode.

Method of driving electrochromic display means and electrochromic

For an electro-optical display having an electrochromic material provided with a redox pair and sandwiched between a pair of electrodes, a first potential more negative than the threshold potential is applied and a second potential more positive than the first potential but more negative than the threshold potential is thereafter applied in a write mode.

Writing/erasing technique for an electrochromic display cell

A driving circuit is provided for an electro-optical display which includes an electrochromic material and a predetermined number of display segments, various combinations of display segments defining different desired display patterns. The electrochromic phenomenon is developed within the electro-optical display upon a flow of current supplied through the display segments. The driving circuit is constructed so as to supply a predetermined amount of the flow of current to the display segments during variations of the light absorption properties.

Constant current supply drive for electrochromic displays of the

An electro-optical display comprises an electrochromic material and a predetermined number of display segments, each combination of the display segments defining a different desired display pattern. Lead-in electrodes connected to the respective display segments for driving purposes are shaped in such a manner as to have resistance values inversely proportional to the size of the corresponding display segments.

Lead-in electrode structure for electrochromic displays of the segmented

A drive system is provided for an electrochromic display which includes an electrochromic material, a display pattern electrode and a counter electrode. The electrochromic phenomenon, or, reversible variations in the light absorption properties are developed when a predetermined voltage is applied between the display pattern electrode and the counter electrode. An erase pulse is applied to a bleached state display pattern electrode when a certain display pattern is held for a period longer than a memory period of the electrochromic display in order to regenerate the memory state and enhance the visibility.

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Nara, Japan

Hiroshi Nakauchi