LIQUID CRYSTAL DISPLAY DEVICE AND ELECTRONIC DEVICE
First Claim
1. A liquid crystal display device comprising:
- a plurality of pixels arranged in a matrix form, each includinga transistor, switching of which is controlled by a scan line driver circuit;
a liquid crystal element including one terminal to which an image signal is input from a signal line driver circuit through the transistor and the other terminal to which a common potential is supplied, so that voltage corresponding to the image signal is applied; and
a capacitor which stores voltage applied to the liquid crystal element,wherein a control circuit which controls operation of the scan line driver circuit and the signal line driver circuit and selects input of the image signal to each pixel is included,wherein the transistor includes a channel formation region comprising an oxide semiconductor layer, andwherein an amount of leakage of the image signal through the transistor in an off state is smaller than an amount of leakage of the image signal through the liquid crystal element.
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Accused Products
Abstract
To reduce power consumption and suppress display degradation of a liquid crystal display device. To suppress display degradation due to an external factor such as temperature. A transistor whose channel formation region is formed using an oxide semiconductor layer is used for a transistor provided in each pixel. Note that with the use of a high-purity oxide semiconductor layer, off-state current of the transistor at a room temperature can be 10 aA/μm or less and off-state current at 85° C. can be 100 aA/μm or less. Consequently, power consumption of a liquid crystal display device can be reduced and display degradation can be suppressed. Further, as described above, off-state current of the transistor at a temperature as high as 85° C. can be 100 aA/μm or less. Thus, display degradation of a liquid crystal display device due to an external factor such as temperature can be suppressed.
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Citations
24 Claims
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1. A liquid crystal display device comprising:
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a plurality of pixels arranged in a matrix form, each including a transistor, switching of which is controlled by a scan line driver circuit; a liquid crystal element including one terminal to which an image signal is input from a signal line driver circuit through the transistor and the other terminal to which a common potential is supplied, so that voltage corresponding to the image signal is applied; and a capacitor which stores voltage applied to the liquid crystal element, wherein a control circuit which controls operation of the scan line driver circuit and the signal line driver circuit and selects input of the image signal to each pixel is included, wherein the transistor includes a channel formation region comprising an oxide semiconductor layer, and wherein an amount of leakage of the image signal through the transistor in an off state is smaller than an amount of leakage of the image signal through the liquid crystal element. - View Dependent Claims (4, 7, 10, 13, 16, 19, 22)
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2. A liquid crystal display device comprising:
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a pixel portion including a plurality of pixels arranged in a matrix form, each including a transistor, switching of which is controlled by a scan line driver circuit; a liquid crystal element including a first electrode to which an image signal is input from a signal line driver circuit through the transistor and a second electrode to which a common potential is applied, so that voltage corresponding to the image signal is applied; and a capacitor which stores the image signal inputted to the first electrode, wherein the pixel portion comprises a memory circuit which stores an image signal for forming a first image to an image signal for forming an n-th image (n is a natural number greater than or equal to
2);a comparison circuit which compares an image signal for forming a k-th image (k is a natural number less than n) and an image signal for forming a (k+1)-th image and detects a difference between the image signals; a selection circuit which selects output of the image signal for forming the (k+1)-th image to the pixel portion based on the difference; and a display control circuit which can perform supply of a control signal to the scan line driver circuit and the signal line driver circuit when the difference is detected, and stop supply of the control signal to the scan line driver circuit and the signal line driver circuit when the difference is not detected, wherein the transistor includes a channel formation region comprising an oxide semiconductor layer, and wherein an amount of leakage of the image signal through the transistor in an off state is smaller than an amount of leakage of the image signal through the liquid crystal element. - View Dependent Claims (5, 8, 11, 14, 17, 20, 23)
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3. A liquid crystal display device comprising:
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a plurality of pixels arranged in a matrix form, each including a transistor; a liquid crystal element electrically connected to the transistor, the liquid crystal element including a terminal which is configured to be supplied with an image signal through the transistor; and a capacitor configured to store a voltage applied to the liquid crystal element; wherein the transistor includes a channel formation region comprising an oxide semiconductor layer, and wherein an amount of leakage of the image signal through the transistor in an off state of the transistor is smaller than an amount of leakage of the image signal through the liquid crystal element. - View Dependent Claims (6, 9, 12, 15, 18, 21, 24)
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Specification