The liquid crystal display device includes an island-shaped first semiconductor film 102 which is formed over a base insulating film 101 and in which a source 102d, a channel forming region 102a, and a drain 102b are formed; a first electrode 102c which is formed of a material same as the first semiconductor film 102 to be the source 102d or the drain 102b and formed over the base insulating film 101; a second electrode 108 which is formed over the first electrode 102c and includes a first opening pattern 112; and a liquid crystal 110 which is provided over the second electrode 108.

An object of the invention is to improve the reliability of a light-emitting device. Another object of the invention is to provide flexibility to a light-emitting device having a thin film transistor using an oxide semiconductor film. A light-emitting device has, over one flexible substrate, a driving circuit portion including a thin film transistor for a driving circuit and a pixel portion including a thin film transistor for a pixel. The thin film transistor for a driving circuit and the thin film transistor for a pixel are inverted staggered thin film transistors including an oxide semiconductor layer which is in contact with a part of an oxide insulating layer.

A transistor whose channel region includes an oxide semiconductor is used as a pull down transistor. The band gap of the oxide semiconductor is 2.0 eV or more, preferably 2.5 eV or more, more preferably 3.0 eV or more. Thus, hot carrier degradation in the transistor can be suppressed. Accordingly, the circuit size of the semiconductor device including the pull down transistor can be made small. Further, a gate of a pull up transistor is made to be in a floating state by switching of onion of the transistor whose channel region includes an oxide semiconductor. Note that when the oxide semiconductor is highly purified, the off-state current of the transistor can be 1 aA/μm (1×10.sup.−18 A/μm) or less. Therefore, the drive capability of the semiconductor device can be improved.

To improve field-effect mobility and reliability of a transistor including an oxide semiconductor film. A semiconductor device includes an oxide semiconductor film, a gate electrode, an insulating film over the gate electrode, the oxide semiconductor film over the insulating film, and a pair of electrodes over the oxide semiconductor film. The oxide semiconductor film includes a first oxide semiconductor film and a second oxide semiconductor film over the first oxide semiconductor film. The first oxide semiconductor film and the second oxide semiconductor film, include the same element. The first oxide semiconductor film includes a region having lower crystallinity than the second oxide semiconductor film.

An object is to shorten the time for rewriting data in memory cells. A memory module includes a first memory cell, a second memory cell, a selection transistor, and a wiring WBL1. The first memory cell includes a first memory node. The second memory cell includes a second memory node. One end of the first memory cell is electrically connected to the wiring WBL1 through the selection transistor. The other end of the first memory cell is electrically connected to one end of the second memory cell. The other end of the second memory cell is electrically connected to the wiring WBL1. When the selection transistor is on, data in the first memory node is rewritten by a signal supplied through the selection transistor to the wiring WBL1. When the selection transistor is off, data in the first memory node is rewritten by a signal supplied through the second memory node to the wiring WBL1.

A display apparatus having a noncontact input function is provided. The display apparatus has a first function of detecting, with a light-receiving device, light irradiated from a light source outside a display portion and blocked by a pointing object to recognize the position pointed by the pointing object, and a second function of detecting, with the light-receiving device, light irradiated from a light source inside or outside the display portion and reflected by the pointing object to recognize the position pointed by the pointing object. The display apparatus can operate by switching the first function and the second function in accordance with the intensity of the light irradiated from the light source outside the display portion.

A display device may include a plurality of pixels each including a light emitting element. A first scan line and a second scan line, are disposed in each of the pixels. A data line is disposed in each of the pixels. A power line is disposed in each of the pixels. A reference voltage line is disposed in each of the pixels. A first transistor controls a current of the light emitting element. A second transistor is connected between the data line and a first gate electrode of the first transistor. A third transistor is connected between the reference voltage line and a first electrode of the first transistor. A fourth transistor is connected between the power line and a second electrode of the first transistor. The fourth transistor may be a transistor of a type different from that of the first to third transistors.

A semiconductor substrate manufacturing method and a semiconductor substrate. The manufacturing method includes: forming a first semiconductor layer on the base substrate at a first temperature with a first oxide semiconductor material; forming the second semiconductor layer directly on the first semiconductor layer with a second oxide semiconductor material; and performing a patterning process such that the first semiconductor layer and the second semiconductor layer are respectively patterned into a seed layer and a first channel layer. Both the first oxide semiconductor material and the second oxide semiconductor material are capable of forming crystalline phases at a second temperature, the second temperature is less than or equal to 40° C., and the first temperature is greater than or equal to 100° C.

An object of one embodiment of the present invention is to propose a memory device in which a period in which data is held is ensured and memory capacity per unit area can be increased. In the memory device of one embodiment of the present invention, bit lines are divided into groups, and word lines are also divided into groups. The word lines assigned to one group are connected to the memory cell connected to the bit lines assigned to the one group. Further, the driving of each group of bit lines is controlled by a dedicated bit line driver circuit of a plurality of bit line driver circuits. In addition, cell arrays are formed on a driver circuit including the above plurality of bit line driver circuits and a word line driver circuit. The driver circuit and the cell arrays overlap each other.

An electronic device including a flexible display panel is provided. The electronic device includes a display panel, a first component, a movable module, and a housing. The housing includes a first movable portion, a second component, and a third component. The third component includes a first space where the first component is stored. The display panel includes a flexible display portion. The display portion includes a first region, a second region, and a third region. The first region is fixed to the second component. The second region is fixed to the first component stored in the third component. The movable module has a function of holding a first angle that is formed between the second component and the third component by the first movable portion. The third region positioned between the first region and the second region has a function of forming a curved surface according to the first angle. The first component slides in the first space according to the first angle.