Electro-optical device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsJun Koyama, Kazutaka Inukai, Shunpei Yamazaki, Mai Osada
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Abstract
An electro-optical device having a plurality of pixels including a plurality of EL elements, wherein the electro-optical device provides a gray scale display by controlling a period of time at which the plurality of the EL elements emit light in one frame period; the plurality of the EL elements have a first electrode and a second electrode; the first electrode is held at a constant potential; and a potential of the second electrode changes in such a manner that a polarity of an EL driving voltage, which is a difference between the potentials applied to the first and second electrodes, is inverted for each one frame period.
Claims45
An electro-luminescence display device comprising a plurality of pixels including a plurality of EL elements, wherein:
- said electro-luminescence display device provides a gray scale display by controlling a sum of lengths of sub-frame periods in which said plurality of EL elements emit light;
- and
- said plurality of EL elements comprise a first electrode, a second electrode, and an organic EL material interposed between the first electrode and the second electrode,
- wherein the plurality of EL elements are arranged to repeat a display state and a non-display state alternatively by inverting a plurality of an EL driving voltage for each one sub-frame period that is included in one frame period, and
- wherein said EL driving voltage is a difference between potentials applied to said first and said second electrodes.
An electro-luminescence display device comprising a plurality of pixels, said device including a plurality of EL elements, a plurality of EL driving TFTs for controlling light emission of said plurality of EL elements, a plurality of switching TFTs for controlling driving of said plurality of EL driving TFTs, wherein:
- said electro-luminescence display device provides a gray scale display by controlling a sum of lengths of sub-frame periods;
- and
- said plurality of EL elements comprise a first electrode, a second electrode, and an organic EL material interposed between the first electrode and the second electrode,
- wherein the plurality of EL elements are arranged to repeat a display state and a non-display state alternatively, by inverting a polarity of an EL driving voltage for each one sub-frame period that is included in one frame period, and
- wherein said EL driving voltage is a difference between potentials applied to said first and said second electrodes.
An electro-luminescence display device comprising a plurality of pixels including a plurality of EL elements, wherein:
- said electro-luminescence display device provides a gray scale display by controlling a sum of lengths of sub-frame periods in which said plurality of EL elements emit light;
- and
- said plurality of EL elements comprise a first electrode, a second electrode, and an organic EL material interposed between the first electrode and the second electrode,
- wherein the plurality of EL elements are arranged to repeat a display state and a non-display state alternatively by inverting a polarity of an EL driving voltage for each one sub-frame period that is included in one frame period,
- wherein adjacent pixels of said plurality of pixels share a power source supply line for supplying a voltage applied to said second electrode, and
- wherein said EL driving voltage is a difference between potentials applied to said first and said second electrodes.
An electro-luminescence display device comprising a plurality of pixels, said device including a plurality of EL elements, a plurality of EL driving TFTs for controlling light emission of said plurality of EL elements, a plurality of switching TFTs for controlling driving of said plurality of EL driving TFTs, wherein:
- said electro-luminescence display device provides a gray scale display by controlling a sum of lengths of sub-frame periods in which said plurality of EL elements emit light;
- and
- said plurality of EL elements comprise a first electrode, a second electrode, and an organic EL material interposed between the first electrode and the second electrode,
- wherein the plurality of EL elements are arranged to repeat a display stale and a non-display state alternatively by inverting a polarity of an EL driving voltage for each one sub-frame period that is included in one frame period,
- wherein adjacent pixels of said plurality of pixels share a power source supply line for supplying a voltage applied to said second electrode, and
- wherein said EL driving voltage is a difference between potentials applied to said first and said second electrodes.
An active matrix-type display device comprising:
- an EL driving thin film transistor over a substrate;
- a switching thin film transistor over the substrate;
- an EL element comprising a first electrode, an organic EL material over the first electrode, and a second electrode over the organic EL material, wherein the EL element is electrically connected to the EL driving thin film transistor;
- a driver circuit comprising a plurality of first thin film transistors over the substrate for driving the switching thin film transistor;
- and
- a time division gray-scale data signal generating circuit comprising a plurality of second thin film transistors over the substrate for dividing one frame period into a plurality of sub-frame periods,
- wherein a gray scale display is provided by controlling a sum of lengths of sub-frame periods in which the EL element emits light,
- wherein the EL element is arranged to repeat a display state and a non-display state alternatively by inverting a polarity of an EL driving voltage for each one sub-frame period that is included in one frame period, and
- wherein the EL driving voltage is a difference between potentials applied to the first and the second electrodes.
An active matrix-type display device comprising:
- an EL driving thin film transistor over a substrate;
- a switching thin film transistor over the substrate;
- and
- an EL element comprising a first electrode, an organic EL material over the first electrode, and a second electrode over the organic EL material, wherein the EL element is electrically connected to the EL driving thin film transistor,
- wherein a gray scale display is provided by controlling a sum of lengths of sub-frame periods in which the EL element emits light,
- wherein a potential of the second electrode is held constant and a potential of the first electrode is arranged to be changed in such a manner that a polarity of an EL driving voltage is inverted for each one sub-frame period,
- wherein the EL element repeats a display state and a non-display state alternatively by the inversion of the polarity of the EL driving voltage for each one sub-frame period that is included in one frame period, and
- wherein the EL driving voltage is a difference between potentials applied to the first and the second electrodes.
An active matrix-type display device comprising:
- an EL driving thin film transistor over a substrate;
- a switching thin film transistor over the substrate;
- a first insulating film comprising a resin material over the EL driving thin film transistor and the switching thin film transistor;
- a second insulating film on a portion of the first insulating film;
- and
- an EL element comprising a first electrode formed on the first insulating film, an organic EL material over the first electrode, and a second electrode over the organic EL material, wherein the EL element is electrically connected to the EL driving thin film transistor,
- wherein a gray scale display is provided by controlling a sum of lengths of sub-frame periods in which the EL element emits light,
- wherein a potential of the first or the second electrode are arranged to be changed in such a manner that a polarity of an EL driving voltage is inverted for each one sub-frame period,
- wherein the EL element repeats a display state and a non-display state alternatively by the inversion of the polarity of the EL driving voltage for each one sub-frame period that is included in one frame period, and
- wherein the EL driving voltage is a difference between potentials applied to the first and the second electrodes.
Dependencies are inferred from the claim text.