Liquid crystal display device and method of driving the same
First Claim
Patent Images
1. A liquid crystal display device wherein n-bit digital picture signals are used to represent gradation where n is a natural number of 2 or more, comprising:
- k pixels wherein k is a natural number of 2 or more, each of the k pixels comprising n memory circuits and a liquid crystal element, and the k pixels comprising a D/A converter circuit;
means for memorizing the n-bit digital picture signals in the n memory circuits;
means for selecting one out of the k pixels and then inputting the n-bit digital picture signals memorized in the selected pixel to the D/A converter circuit; and
means for inputting analogue signals outputted from the D/A converter circuit to the liquid crystal element of the selected pixel.
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Abstract
An object of the present invention is to provide a liquid crystal display device making it possible to lower the power consumption thereof when a still image is displayed. In a liquid crystal display device having memory circuits in each of the pixel, and each group of the pixels shares one D/A converter circuit. In this way, the area of the D/A converter circuit per pixel can be reduced. Accordingly, the number of the memory circuits arranged in each of the pixels can be made large.
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Citations
60 Claims
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1. A liquid crystal display device wherein n-bit digital picture signals are used to represent gradation where n is a natural number of 2 or more, comprising:
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k pixels wherein k is a natural number of 2 or more, each of the k pixels comprising n memory circuits and a liquid crystal element, and the k pixels comprising a D/A converter circuit;
means for memorizing the n-bit digital picture signals in the n memory circuits;
means for selecting one out of the k pixels and then inputting the n-bit digital picture signals memorized in the selected pixel to the D/A converter circuit; and
means for inputting analogue signals outputted from the D/A converter circuit to the liquid crystal element of the selected pixel. - View Dependent Claims (2, 3, 4, 5, 7, 8, 9, 10, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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6. A liquid crystal display device wherein n-bit digital picture signals are used to represent gradation where n is a natural number of 2 or more, comprising:
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k pixels wherein k is a natural number of 2 or more;
a gate signal line driving circuit;
a source signal line driving circuit, the k pixels comprising a D/A converter circuit, and each of the k pixels comprising n memory circuits, a liquid crystal element, and n switching elements which can be in a conductive state by output signals from the gate signal line driving circuit;
means for inputting output signals from the source signal line driving circuit, through each of the n switching elements, to each of the n memory circuits;
means for selecting one out of the k pixels and then inputting the n-bit digital picture signals memorized in the selected pixel to the D/A converter circuit; and
means for inputting analogue signals outputted from the D/A converter circuit to the liquid crystal element of the selected pixel. - View Dependent Claims (11, 12, 13, 14, 16, 17, 18, 19, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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15. A method of driving a liquid crystal display device wherein n-bit digital picture signals are used to represent gradation where n is a natural number of 2 or more,
the liquid crystal display device comprising k pixels wherein k is a natural number of 2 or more, each of the k pixels comprising n memory circuits and a liquid crystal element, and the k pixels comprising a D/A converter circuit, and the method comprising: -
the first step of memorizing the n-bit digital picture signals in the n memory circuits;
the second step of selecting one out of the k pixels and then inputting the n-bit digital picture signals memorized in the selected pixel to the D/A converter circuit; and
the third step of inputting analogue signals outputted from the D/A converter circuit to the liquid crystal element of the selected pixel.
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20. A method of driving liquid crystal display device wherein n-bit digital picture signals are used to represent gradation where n is a natural number of 2 or more,
the liquid crystal display device comprising k pixels wherein k is a natural number of 2 or more, a gate signal line driving circuit, and a source signal line driving circuit, the k pixels comprising a D/A converter circuit, and each of the k pixels comprising n memory circuits, a liquid crystal element, and n switching elements which can be in a conductive state by output signals from the gate signal line driving circuit, and the method comprising: -
the first step of inputting output signals from the source signal line driving circuit, through each of the n switching elements, to each of the n memory circuits;
the second step of selecting one out of the k pixels and then inputting the n-bit digital picture signals memorized in the selected pixel to the D/A converter circuit; and
the third step of inputting analogue signals outputted from the D/A converter circuit to the liquid crystal element of the selected pixel. - View Dependent Claims (21, 22, 23, 24, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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Specification
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Current AssigneeSemiconductor Energy Laboratory Co., Ltd.
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Original AssigneeSemiconductor Energy Laboratory Co., Ltd.
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InventorsKoyama, Jun
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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current345/87
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CPC Class CodesG09G 2300/0809 Several active elements per...G09G 2300/0842 forming a memory circuit, e...G09G 2300/0857 Static memory circuit, e.g....G09G 2310/027 Details of drivers for data...G09G 2310/0294 Details of sampling or hold...G09G 2330/021 Power management, e.g. powe...G09G 3/3648 using an active matrix G09G...G09G 3/3688 suitable for active matrice...
