Abstract: An object is to provide a pulse signal output circuit capable of operating stably and a shift register including the pulse signal output circuit. A pulse signal output circuit according to one embodiment of the disclosed invention includes first to tenth transistors. The ratio W/L of the channel width W to the channel length L of the first transistor and W/L of the third transistor are each larger than W/L of the sixth transistor. W/L of the fifth transistor is larger than W/L of the sixth transistor. W/L of the fifth transistor is equal to W/L of the seventh transistor. W/L of the third transistor is larger than W/L of the fourth transistor. With such a structure, a pulse signal output circuit capable of operating stably and a shift register including the pulse signal output circuit can be provided.

Abstract: A pixel is divided into m (m is an integer of m?2) sub-pixels, and an area ratio of an s-th (s is an integer of 1 to m) sub-pixel is to be 2s-1. Also, k (k is an integer of k?2) sub-frame groups including a plurality of sub-frames are provided in one frame, along with dividing one frame into n (n is an integer of n?2) sub-frames, so that a ratio of a lighting period length of a t-th (t is an integer of 1 to n) sub-frame is 2(t-1)m. Further, each of the n sub-frames is divided into k sub-frames each having a lighting period length that is about 1/k of each of the n sub-frames, and one of these is provided in each of the k sub-frame groups.

Abstract: To suppress variation of a signal in a semiconductor device. By suppressing the variation, formation of a stripe pattern in displaying an image on a semiconductor device can be suppressed, for example. A distance between two adjacent signal lines which go into a floating state in different periods (G1) is longer than a distance between two adjacent signal lines which go into a floating state in the same period (G0, G2). Consequently, variation in potential of a signal line due to capacitive coupling can be suppressed. For example, in the case where the signal line is a source signal line in an active matrix display device, formation of a stripe pattern in a displayed image can be suppressed.

Abstract: To reduce a pseudo contour which occurs when displaying by a time gray scale method. When gradation is expressed with an n bit, bits each of which is shown by a binary of the gray scales are divided into three bit groups, and one frame is divided into two subframe groups. Then, a (0<a<n) subframes corresponding to bits belonging to a first bit group are divided into three or more, each about half of which is arranged in each subframe group; b (0<b<n) subframes corresponding to bits belonging to a second bit group are divided into two, each one of which is arranged in each the subframe group; and c (0?c<n and a+b+c=n) subframes corresponding to bits belonging to a third bit group are arranged in at least one of the subframe groups. And then, an overlapped time gray scale method is applied in each subframe group to express gradation.

Abstract: A liquid crystal display device is provided in which the aperture ratio can be increased in a pixel including a thin film transistor in which an oxide semiconductor is used. In the liquid crystal display device, the thin film transistor including a gate electrode, a gate insulating layer and an oxide semiconductor layer which are provided so as to overlap with the gate electrode, and a source electrode and a drain electrode which overlap part of the oxide semiconductor layer is provided between a signal line and a pixel electrode which are provided in a pixel portion. The off-current of the thin film transistor is 1×10?13 A or less. A potential can be held only by a liquid crystal capacitor, without a capacitor which is parallel to a liquid crystal element, and a capacitor connected to the pixel electrode is not formed in the pixel portion.

Abstract: A pixel is divided into m (m is an integer of m?2) sub-pixels, and an area ratio of an s-th (s is an integer of 1 to m) sub-pixel is to be 2s?1. Also, k (k is an integer of k?2) sub-frame groups including a plurality of sub-frames are provided in one frame, along with dividing one frame into n (n is an integer of n?2) sub-frames, so that a ratio of a lighting period length of a t-th (t is an integer of 1 to n) sub-frame is 2(t?1)m. Further, each of the n sub-frames is divided into k sub-frames each having a lighting period length that is about 1/k of each of the n sub-frames, and one of these is provided in each of the k sub-frame groups.

Abstract: An object is to provide a light-emitting display device in which a pixel including a thin film transistor using an oxide semiconductor has a high aperture ratio. The light-emitting display device includes a plurality of pixels each including a thin film transistor and a light-emitting element. The pixel is electrically connected to a first wiring functioning as a scan line. The thin film transistor includes an oxide semiconductor layer over the first wiring with a gate insulating film therebetween. The oxide semiconductor layer is extended beyond the edge of a region where the first wiring is provided. The light-emitting element and the oxide semiconductor layer overlap with each other.

Abstract: An object is to provide a liquid crystal display device in which a pixel including a thin film transistor using an oxide semiconductor has a high aperture ratio. The liquid crystal display device includes a plurality of pixels each including a thin film transistor and a pixel electrode. The pixel is electrically connected to a first wiring functioning as a scan line. The thin film transistor includes an oxide semiconductor layer over the first wiring with a gate insulating film therebetween. The oxide semiconductor layer is extended beyond the edge of a region where the first wiring is provided. The pixel electrode and the oxide semiconductor layer overlap with each other.

Abstract: The present invention has a photodiode and a circuit used to amplify the output of the photodiode. Two terminals are formed over the photodiode and circuit with an insulating layer interposed therebetween, and a dummy electrode with a larger area than that of either of the two terminals is formed thereover, adjacent to the two terminals. The dummy electrode is not connected to the photodiode or to the circuit of the semiconductor device. Because the dummy electrode has a wide area, damage due to electrostatic discharge occurs in the dummy electrode more easily than in the two terminals; thus, damage due to electrostatic discharge can be prevented from occurring in the semiconductor device.

Abstract: Disclosed is a semiconductor device which consumes low power and has high reliability and tolerance for electrostatic discharge. The semiconductor device includes, over a first substrate, a pixel portion and a driver circuit portion both of which have a thin film transistor having an oxide semiconductor layer. The semiconductor device further possesses a second substrate to which a first counter electrode layer and a second counter electrode layer are provided, and a liquid crystal layer is interposed between the first and second substrates. The first and second counter electrode layers are provided over the pixel portion and the driver circuit portion, respectively, and the second counter electrode layer has the same potential as the first counter electrode layer.

Abstract: A protection circuit used for a semiconductor device is made to effectively function and the semiconductor device is prevented from being damaged by a surge. A semiconductor device includes a terminal electrode, a protection circuit, an integrated circuit, and a wiring electrically connecting the terminal electrode, the protection circuit, and the integrated circuit. The protection circuit is provided between the terminal electrode and the integrated circuit. The terminal electrode, the protection circuit, and the integrated circuit are connected to one another without causing the wiring to branch. It is possible to reduce the damage to the semiconductor device caused by electrostatic discharge. It is also possible to reduce faults in the semiconductor device.

Abstract: A cooling device is provided, where an LED backlight can be efficiently cooled in order to suppress display unevenness caused by heat generated from the LED backlight. In addition, a display device including the cooling device is also provided. A display device is provided, where the LED backlight can be cooled by arranging a coolant pipe on a back surface side of the LED backlight and supplying a coolant to a coolant pipe. Further, a display device is provided, where cooling efficiency of the LED backlight can be more improved by arranging a thermal conductor between the LED backlight and the cooling device.

Abstract: One feature of the present invention includes first to third steps of holding a voltage, corresponding to a difference between a voltage applied to a first power supply line and a threshold voltage of a first transistor, between both electrodes of first and second storage capacitors; holding a voltage, corresponding to a difference between a voltage applied to the first power supply line and a gate-source voltage of the first transistor, which is necessary to supply a light-emitting element with a current equivalent to a video signal current inputted into a signal line, between both the electrodes of the second storage capacitor; and applying a voltage based on the voltage held in the first and second storage capacitors in the first and second steps to a gate electrode of the first transistor; therefore, a current is supplied to the light-emitting element through the first transistor.

Abstract: The threshold voltage is shifted in a negative or positive direction in some cases by an unspecified factor in a manufacturing process of the thin film transistor. If the amount of shift from 0 V is large, driving voltage is increased, which results in an increase in power consumption of a semiconductor device. Thus, a resin layer having good flatness is formed as a first protective insulating film covering the oxide semiconductor layer, and then a second protective insulating film is formed by a sputtering method or a plasma CVD method under a low power condition over the resin layer. Further, in order to adjust the threshold voltage to a desired value, gate electrodes are provided over and below an oxide semiconductor layer.

Abstract: It is an object to provide a protection circuit and a semiconductor device to which a countermeasure against ESD is applied. The protection circuit includes a signal line electrically connected to an integrated circuit; a first diode provided between the signal line and a first power supply line; a second diode provided in parallel to the first diode; and a third diode provided between the first power supply line and a second power supply line. The first diode is a diode formed by diode-connecting a transistor, and the second diode is a diode having a PIN junction or a PN junction. The protection circuit is particularly effective when applied to a semiconductor device manufactured using a thin film transistor.

Abstract: A cooling device is provided, where an LED backlight can be efficiently cooled in order to suppress display unevenness caused by heat generated from the LED backlight. In addition, a display device including the cooling device is also provided. A display device is provided, where the LED backlight can be cooled by arranging a coolant pipe on a back surface side of the LED backlight and supplying a coolant to a coolant pipe. Further, a display device is provided, where cooling efficiency of the LED backlight can be more improved by arranging a thermal conductor between the LED backlight and the cooling device.

Abstract: One feature of the present invention includes first to third steps of holding a voltage, corresponding to a difference between a voltage applied to a first power supply line and a threshold voltage of a first transistor, between both electrodes of first and second storage capacitors; holding a voltage, corresponding to a difference between a voltage applied to the first power supply line and a gate-source voltage of the first transistor, which is necessary to supply a light-emitting element with a current equivalent to a video signal current inputted into a signal line, between both the electrodes of the second storage capacitor; and applying a voltage based on the voltage held in the first and second storage capacitors in the first and second steps to a gate electrode of the first transistor; therefore, a current is supplied to the light-emitting element through the first transistor.

Abstract: To reduce a pseudo contour which occurs when displaying by a time gray scale method. When gradation is expressed with an n bit, bits each of which is shown by a binary of the gray scales are divided into three bit groups, and one frame is divided into two subframe groups. Then, a (0<a<n) subframes corresponding to bits belonging to a first bit group are divided into three or more, each about half of which is arranged in each subframe group; b (0<b<n) subframes corresponding to bits belonging to a second bit group are divided into two, each one of which is arranged in each the subframe group; and c (0?c<n and a+b+c=n) subframes corresponding to bits belonging to a third bit group are arranged in at least one of the subframe groups. And then, an overlapped time gray scale method is applied in each subframe group to express gradation.

Abstract: An object is to provide a photoelectric conversion device which can correct a difference between a measured light intensity and an actual light intensity, which occurs when output current decreases due to the fact that a strong light is received, and outputs the corrected current. The photoelectric conversion device includes a photoelectric conversion element; a photocurrent output circuit for providing a first current corresponding to the amount of incident light on the photoelectric conversion element; a photocurrent correcting circuit which includes a corrective photoelectric conversion element for providing a second current, the corrective photoelectric conversion element including a light shield film for blocking part of light; a photocurrent adder circuit which includes a circuit for providing a fourth current; and an amplifier circuit including a circuit which amplifies a current corresponding to the sum of the first current and the fourth current and outputs the amplified current.

Abstract: The present invention provides a driving method of a display device for expressing gray scales with n bits (n is an integer) by dividing one frame into a plurality of subframes. By this driving method, pseudo contours which occur in displaying images by a time gray scale method can be reduced.