LIQUID CRYSTAL DISPLAY DEVICE AND ELECTRONIC DEVICE INCLUDING THE LIQUID CRYSTAL DISPLAY DEVICE
In a liquid crystal display device including a plurality of pixels in a display portion and configured to performed display in a plurality of frame periods, each of the frame periods includes a writing period and a holding period, and after an image signal is input to each of the plurality of pixels in the writing period, a transistor included in each of the plurality of pixels is turned off and the image signal is held for at least 30 seconds in the holding period. The pixel includes a semiconductor layer including an oxide semiconductor layer, and the oxide semiconductor layer has a carrier concentration of less than 1×10 14 /cm 3 .
1 . (canceled)
2 . A display device comprising:
a transistor comprising a source, a drain and a channel formation region, the channel formation region comprising an oxide semiconductor;
a pixel electrode electrically connected to the source or the drain of the transistor; and
a liquid crystal material adjacent to the pixel electrode,
wherein a specific resistance of the liquid crystal material measured at 20° C. is 1×10 12 Ω·cm or more.
3 . A display device comprising:
a transistor comprising a source, a drain and a channel formation region, the channel formation region comprising an oxide semiconductor; and
a pixel electrode electrically connected to the source or the drain of the transistor,
wherein an energy gap of the oxide semiconductor is 2 eV or more, and
wherein a current per micrometer of a channel width of the channel formation region is 1×10 −17 A or less.
4 . A display device comprising a plurality of pixels in a display portion and configured to perform display in a plurality of frame periods, each of the plurality of pixels comprising:
a transistor comprising a source, a drain and a channel formation region, the channel formation region comprising an oxide semiconductor; and
a pixel electrode electrically connected to the source or the drain of the transistor,
wherein each of the plurality of frame periods includes a writing period and a holding period,
wherein the holding period is variable, and
wherein the pixel electrode is a reflective electrode.
5 . A display device comprising a plurality of pixels in a display portion and configured to perform display in a plurality of frame periods, each of the plurality of pixels comprising:
a transistor comprising a source, a drain and a channel formation region, the channel formation region comprising an oxide semiconductor; and
a pixel electrode electrically connected to the source or the drain of the transistor,
wherein each of the plurality of frame periods includes a writing period and a holding period,
wherein the holding period is within a range such that an image burn-in does not occur, and
wherein the pixel electrode is a reflective electrode.
6 . A display device comprising a plurality of pixels in a display portion and configured to perform display in a plurality of frame periods, each of the plurality of pixels comprising:
a transistor comprising a source, a drain and a channel formation region, the channel formation region comprising an oxide semiconductor; and
a pixel electrode electrically connected to the source or the drain of the transistor,
wherein each of the plurality of frame periods includes a writing period and a holding period,
wherein the holding period is at least 10 seconds, and
wherein the pixel electrode is a reflective electrode.
7 . A display device comprising:
a transistor comprising a source, a drain and a channel formation region, the channel formation region comprising an oxide semiconductor; and
a pixel electrode electrically connected to the source or the drain of the transistor,
wherein a frequency of signal writing of a still image is lower than that of a moving image.
8 . The display device according to claim 2 , wherein the oxide semiconductor includes indium.
9 . The display device according to claim 3 , wherein the oxide semiconductor includes indium.
10 . The display device according to claim 4 , wherein the oxide semiconductor includes indium.
11 . The display device according to claim 5 , wherein the oxide semiconductor includes indium.
12 . The display device according to claim 6 , wherein the oxide semiconductor includes indium.
13 . The display device according to claim 7 , wherein the oxide semiconductor includes indium.
14 . The display device according to claim 2 , wherein the oxide semiconductor includes a microcrystalline portion with a grain diameter of 1 nm to 20 nm.
15 . The display device according to claim 3 , wherein the oxide semiconductor includes a microcrystalline portion with a grain diameter of 1 nm to 20 nm.
16 . The display device according to claim 4 , wherein the oxide semiconductor includes a microcrystalline portion with a grain diameter of 1 nm to 20 nm.
17 . The display device according to claim 5 , wherein the oxide semiconductor includes a microcrystalline portion with a grain diameter of 1 nm to 20 nm.
18 . The display device according to claim 6 , wherein the oxide semiconductor includes a microcrystalline portion with a grain diameter of 1 nm to 20 nm.
19 . The display device according to claim 7 , wherein the oxide semiconductor includes a microcrystalline portion with a grain diameter of 1 nm to 20 nm.
20 . The display device according to claim 3 , wherein the display device is a liquid crystal display device, an electroluminescent display device, or a display device using electronic ink.
21 . The display device according to claim 4 , wherein the display device is a liquid crystal display device, an electroluminescent display device, or a display device using electronic ink.
22 . The display device according to claim 5 , wherein the display device is a liquid crystal display device, an electroluminescent display device, or a display device using electronic ink.
23 . The display device according to claim 6 , wherein the display device is a liquid crystal display device, an electroluminescent display device, or a display device using electronic ink.
24 . The display device according to claim 7 , wherein the display device is a liquid crystal display device, an electroluminescent display device, or a display device using electronic ink.
25 . The display device according to claim 2 ,
wherein an energy gap of the oxide semiconductor is 2 eV or more, and
wherein a current per micrometer of a channel width of the channel formation region is 1×10 −17 A or less.
26 . The display device according to claim 4 ,
wherein an energy gap of the oxide semiconductor is 2 eV or more, and
wherein a current per micrometer of a channel width of the channel formation region is 1×10 −17 A or less.
27 . The display device according to claim 5 ,
wherein an energy gap of the oxide semiconductor is 2 eV or more, and
wherein a current per micrometer of a channel width of the channel formation region is 1×10 −17 A or less.
28 . The display device according to claim 6 ,
wherein an energy gap of the oxide semiconductor is 2 eV or more, and
wherein a current per micrometer of a channel width of the channel formation region is 1×10 −17 A or less.
29 . The display device according to claim 7 ,
wherein an energy gap of the oxide semiconductor is 2 eV or more, and
wherein a current per micrometer of a channel width of the channel formation region is 1×10 −17 A or less.
30 . The display device according to claim 2 , wherein the pixel electrode is a reflective electrode.
31 . The display device according to claim 3 , wherein the pixel electrode is a reflective electrode.
32 . The display device according to claim 7 , wherein the pixel electrode is a reflective electrode.
33 . The display device according to claim 4 , wherein the pixel electrode includes at least one selected from a group consisting of tungsten, molybdenum, zirconium, hafnium, vanadium, niobium, tantalum, chromium, cobalt, nickel, titanium, platinum, aluminum, copper, and silver.
34 . The display device according to claim 5 , wherein the pixel electrode includes at least one selected from a group consisting of tungsten, molybdenum, zirconium, hafnium, vanadium, niobium, tantalum, chromium, cobalt, nickel, titanium, platinum, aluminum, copper, and silver.
35 . The display device according to claim 6 , wherein the pixel electrode includes at least one selected from a group consisting of tungsten, molybdenum, zirconium, hafnium, vanadium, niobium, tantalum, chromium, cobalt, nickel, titanium, platinum, aluminum, copper, and silver.
36 . The display device according to claim 3 , further comprising a liquid crystal layer,
wherein the liquid crystal layer comprises a twisted nematic mode.
37 . The display device according to claim 6 , further comprising a liquid crystal layer,
wherein the liquid crystal layer comprises a twisted nematic mode.
38 . The display device according to claim 7 , further comprising a liquid crystal layer,
wherein the liquid crystal layer comprises a twisted nematic mode.
39 . The display device according to claim 3 , wherein the oxide semiconductor has a carrier concentration of less than 1×10 14 /cm 3 .
40 . The display device according to claim 4 , wherein the holding period is variable in accordance with a holding rate of a voltage applied to a display element during the holding period.
41 . The display device according to claim 5 , wherein a polarity of a voltage applied to a display element is inverted in each of the plurality of frame periods.
42 . The display device according to claim 2 ,
wherein the display device is configured to perform display in a plurality of frame periods,
wherein each of the plurality of frame periods includes a writing period and a holding period, and
wherein the holding period is within a range such that an image burn-in does not occur.
43 . The display device according to claim 3 ,
wherein the display device is configured to perform display in a plurality of frame periods,
wherein each of the plurality of frame periods includes a writing period and a holding period, and
wherein the holding period is within a range such that an image burn-in does not occur.
44 . The display device according to claim 7 ,
wherein the display device is configured to perform display in a plurality of frame periods,
wherein each of the plurality of frame periods includes a writing period and a holding period, and
wherein the holding period is within a range such that an image burn-in does not occur.
45 . The display device according to claim 3 , further comprising a liquid crystal material adjacent to the pixel electrode,
wherein a specific resistance of the liquid crystal material measured at 20° C. is 1×10 12 Ω·cm or more.
46 . The display device according to claim 4 , further comprising a liquid crystal material adjacent to the pixel electrode,
wherein a specific resistance of the liquid crystal material measured at 20° C. is 1×10 12 Ω·cm or more.
47 . The display device according to claim 5 , further comprising a liquid crystal material adjacent to the pixel electrode,
wherein a specific resistance of the liquid crystal material measured at 20° C. is 1×10 12 Ω·cm or more.
48 . The display device according to claim 6 , further comprising a liquid crystal material adjacent to the pixel electrode,
wherein a specific resistance of the liquid crystal material measured at 20° C. is 1×10 12 Ω·cm or more.
49 . The display device according to claim 7 , further comprising a liquid crystal material adjacent to the pixel electrode,
wherein a specific resistance of the liquid crystal material measured at 20° C. is 1×10 12 Ω·cm or more.
50 . The display device according to claim 2 , wherein the specific resistance of the liquid crystal material measured at 20° C. is 1×10 14 Ω·cm or more.
51 . The display device according to claim 4 , wherein a refresh operation is performed at a timing when a voltage applied to a display element is decreased to a predetermined level with respect to an initial value.
52 . The display device according to claim 5 , wherein the display device is driven by dot inversion driving.
53 . The display device according to claim 6 , wherein the display device is driven by dot inversion driving.
54 . The display device according to claim 7 , wherein the display device is driven by dot inversion driving.