Abstract:
A display system in which the luminance of light-emitting elements in a light-emitting device is adjusted based on information on an environment. A sensor obtains information on an environment as an electrical signal. A CPU converts, based on comparison data set in advance, the information signal into a correction signal for correcting the luminance of EL elements. Upon receiving this correction signal, a voltage changer applies a predetermined corrected potential to the EL elements. Thus, this display system enables control of the luminance of the EL elements.
Abstract:
When a pixel portion and a driver circuit are formed over one substrate and a counter electrode is formed over an entire surface of a counter substrate, the driver circuit may be adversely affected by an optimized voltage of the counter electrode. A semiconductor device according to the present invention has a structure in which: a liquid crystal layer is provided between a pair of substrates; one of the substrates is provided with a pixel electrode and a driver circuit; the other of the substrates is a counter substrate which is provided with two counter electrode layers in different potentials; and one of the counter electrode layers overlaps with the pixel electrode with the liquid crystal layer therebetween and the other of the counter electrode layers overlaps with the driver circuit with the liquid crystal layer therebetween. An oxide semiconductor layer is used for the driver circuit.
Abstract:
In the case where a still image is displayed on a pixel portion having a pixel, for example, a driver circuit for controlling writing of an image signal having image data to the pixel portion stops by stopping supply of power supply voltage to the driver circuit, and writing of an image signal to the pixel portion is stopped. After the driver circuit stops, supply of power supply voltage to a panel controller for controlling the operation of the driver circuit and an image memory for storing the image data is stopped, and supply of power supply voltage to a CPU for collectively controlling the operation of the panel controller, the image memory, and a power supply controller for controlling supply of power supply voltage to a variety of circuits in a semiconductor display device is stopped.
Abstract:
Write in of lower significant bits of a digital video signal to a memory is eliminated by a memory controller of a signal control circuit in a display device during a second display mode in which the number of gray scales is reduced, as compared to a first display mode. Further, read out of the lower significant bits of the digital video signal from the memory is also eliminated. The amount of information of digital image signals input to a source signal line driver circuit is reduced. Corresponding to this operation, a display controller functions to make start pulses and clock pulses input to each driver circuit have a lower frequency, and write in periods and display periods of sub-frame periods participating in display are set longer.
Abstract:
A liquid crystal display device capable of consuming less power and a method for driving the liquid crystal display device are provided. The liquid crystal display device includes a pixel portion, a light supply portion sequentially supplying lights of a plurality of hues to the pixel portion, a counter counting the number of frame periods, a signal generator determining timing of inverting the polarity of an image signal every plural consecutive frame periods by using data on the number of frame periods counted by the counter, and a controller inverting the polarity of the image signal in accordance with the timing. A plurality of pixels are provided in the pixel portion. The image signal whose polarity is inverted every plural frame periods is input to the plurality of pixels.
Abstract:
To provide a highly accurate temperature sensor circuit. The temperature sensor circuit includes a first constant current circuit; a first diode in which a first voltage reflecting the temperature of an object to be detected is generated between an anode and a cathode in accordance with a first current supplied from the first constant current circuit; a second constant current circuit; a second diode which includes an oxide semiconductor and in which a second voltage is generated between an anode and a cathode in accordance with a second current supplied from the second constant current circuit; and an amplifier circuit which amplifies a difference between the first voltage and the second voltage.
Abstract:
A semiconductor device includes first and second transistors having the same conductivity type and a circuit. One of a source and a drain of the first transistor is electrically connected to that of the second transistor. First and third potentials are supplied to the circuit through respective wirings. A second potential and a first clock signal are supplied to the others of the sources and the drains of the first and second transistors, respectively. A second clock signal is supplied to the circuit. The third potential is higher than the second potential which is higher than the first potential. A fourth potential is equal to or higher than the third potential. The first clock signal alternates the second and fourth potentials and the second clock signal alternates the first and third potentials. The circuit controls electrical connections between gates of the first and second transistors and the wirings.
Abstract:
A semiconductor device capable of wireless communication, which has high reliability in terms of resistance to external force, in particular, pressing force and can prevent electrostatic discharge in an integrated circuit without preventing reception of an electric wave. The semiconductor device includes an on-chip antenna connected to the integrated circuit and a booster antenna which transmits a signal or power included in a received electric wave to the on-chip antenna without contact. In the semiconductor device, the integrated circuit and the on-chip antenna are interposed between a pair of structure bodies formed by impregnating a fiber body with a resin. One of the structure bodies is provided between the on-chip antenna and the booster antenna. A conductive film having a surface resistance value of approximately 106 to 1014 Ω/cm2 is formed on at least one surface of each structure body.
Abstract:
An object of the present invention is to provide a driver circuit including a normally-on thin film transistor, which driver circuit ensures a small malfunction and highly reliable operation. The driver circuit includes a static shift register including an inverter circuit having a first transistor and a second transistor, and a switch including a third transistor. The first to third transistors each include a semiconductor layer of an oxide semiconductor and are depletion-mode transistors. An amplitude voltage of clock signals for driving the third transistor is higher than a power supply voltage for driving the inverter circuit.
Abstract:
To stably control a threshold voltage of a functional circuit using an oxide semiconductor. A variable bias circuit, a monitoring oxide semiconductor transistor including a back gate, a current source, a differential amplifier, a reference voltage source, and a functional circuit which includes an oxide semiconductor transistor including a back gate are provided. The current source supplies current between a source and a drain of the monitoring oxide semiconductor transistor to generate a gate-source voltage in accordance with the current. The differential amplifier compares the voltage with a voltage of the reference voltage source, amplifies a difference, and outputs a resulting voltage to the variable bias circuit. The variable bias circuit is controlled by an output of the differential amplifier and supplies voltage to the back gate of the monitoring oxide semiconductor transistor and the back gate of the oxide semiconductor transistor included in the functional circuit.