摘要:
A photometric device with a wide dynamic range. The photometric device includes a constant current generation circuit, a fixed clock signal generation circuit which generates a fixed clock signal having a fixed frequency, a photoelectric conversion element, a variable clock signal generation circuit, and a digital signal generation circuit. The fixed clock signal generation circuit generates a fixed clock signal that oscillates at a fixed frequency, from constant current. The variable clock signal generation circuit generates a variable clock signal that oscillates at a frequency proportional to the amount of photocurrent, from photocurrent generated in the photoelectric conversion element. The digital signal generation circuit sets a measurement period using the fixed clock signal, counts the number of pulses of the variable clock signal that oscillates for the measurement period, and outputs a digital signal including the count value as data.
摘要:
Objects are to accumulate electric charge in a capacitor so that light intensity can be detected even when the amount of incident light is small, and to operate a photoelectric conversion device without increasing the number of elements such as a constant current source or a switch. The photoelectric conversion device includes a photoelectric conversion circuit, a capacitor, and a comparator for comparing a potential of one electrode of the capacitor with a second potential. The photoelectric conversion circuit includes a photoelectric conversion element and an amplifier circuit for amplifying an output current from the photoelectric conversion element In the capacitor, a first potential is supplied through a first switch, and charging or discharging is performed through a second switch in accordance with the current amplified by the amplifier circuit.
摘要:
An object is to reduce power consumption of a display device and to suppress deterioration of display quality. As a transistor provided for each pixel, a transistor including an oxide semiconductor layer is used. Note that off-state current of the transistor can be decreased when the oxide semiconductor layer is highly purified. Therefore, variation in the value of a data signal due to the off-state current of the transistor can be suppressed. That is, display deterioration (change) which occurs when writing frequency of the data signal to the pixel including the transistor is reduced (when a break period is lengthened) can be suppressed. In addition, flickers in display which generates when the frequency of an alternating-current driving signal supplied to a signal line in the break period is reduced can be suppressed.
摘要:
To provide a display device with little signal delay and a display device that can operate with low power consumption, parasitic capacitance between a common wiring that applies a common potential to a plurality of pixels and signal lines that input signals for driving the pixels is avoided. Specifically, the common wiring is routed outwardly with respect to an external input terminal to which a signal is input from the, outside, to avoid intersections of the signal lines and the common wiring. Thus, parasitic capacitance between the common wiring and the signal lines is avoided, so that the display device can operate at high speed with low power consumption.
摘要:
An object is to provide a three-dimensional display device capable of displaying bright images with low power consumption. The display device includes: an image display portion including a pixel portion provided with a plurality of pixels; a light-blocking portion including a first shutter and a second shutter; a signal source outputting the common potential; and a controller controlling transmittances of the first shutter and the second shutter and level of the common potential output from the signal source to bring the transmittances and the level into synchronism with supply of an image signal, display of a right-eye image, or display of a left-eye image performed in the pixel portion.
摘要:
An object is to provide a liquid crystal display device capable of image display according to an environment around the liquid crystal display device, e.g., in a bright environment or a dim environment. Another object is to provide a liquid crystal display device capable of displaying an image in both modes of a reflective mode in which external light is used as a light source and a transmissive mode in which a backlight is used. In order to achieve at least one of the above objects, a liquid crystal display device is provided with a region (a reflective region) where display is performed with reflection of incident light through a liquid crystal layer and a region (a transmissive region) where display is performed with transmission of light from a backlight and can switch the transmissive mode and the reflective mode. In the case where a full-color image is displayed, a pixel portion includes at least a first region and a second region, a plurality of lights of different hues are sequentially supplied to the first region according to a first order, and a plurality of lights of different hues are also sequentially supplied to the second region according to a second order which is different from the first order.
摘要:
An object is at least one of a longer data retention period of a memory circuit, a reduction in power consumption, a smaller circuit area, and an increase in the number of times written data can be read to one data writing operation. The memory circuit has a first field-effect transistor, a second field-effect transistor, and a rectifier element including a pair of current terminals. A data signal is input to one of a source and a drain of the first field-effect transistor. A gate of the second field-effect transistor is electrically connected to the other of the source and the drain of the first field-effect transistor. One of the pair of current terminals of the rectifier element is electrically connected to a source or a drain of the second field-effect transistor.
摘要:
It is an object to provide a semiconductor display device having a touch panel, which can reduce power consumption. The semiconductor display device includes a panel which is provided with a pixel portion and a driver circuit which controls an input of the image signal to the pixel portion, and a touch panel provided in a position overlapping with the panel in the pixel portion. The pixel portion includes a display element configured to perform display in accordance with voltage of the image signal to be input, and a transistor configured to control retention of the voltage. The transistor includes an oxide semiconductor in a channel formation region. The driving frequency of the driver circuit, that is, the number of writing operations of the image signal for a certain period is changed in accordance with an operation signal from a touch panel.
摘要:
The silicon nitride layer 910 formed by plasma CVD using a gas containing a hydrogen compound such as silane (SiH4) and ammonia (NH3) is provided on and in direct contact with the oxide semiconductor layer 905 used for the resistor 354, and the silicon nitride layer 910 is provided over the oxide semiconductor layer 906 used for the thin film transistor 355 with the silicon oxide layer 909 serving as a barrier layer interposed therebetween. Therefore, a higher concentration of hydrogen is introduced into the oxide semiconductor layer 905 than into the oxide semiconductor layer 906. As a result, the resistance of the oxide semiconductor layer 905 used for the resistor 354 is made lower than that of the oxide semiconductor layer 906 used for the thin film transistor 355.
摘要:
The number of operation keys is normally on the order of 12 to 20, corresponding to numeral keys and specialized keys, even for a portable telephone device capable of sending signals to, and receiving signals from, the Internet. In order to input Japanese language characters, including kanji, and specialized characters as data, a complex operation is necessary for switching the input mode. With the present invention, display devices are formed in operation keys for inputting information to electronic devices such as portable information terminals, typically portable telephone devices, and information terminals, typically personal computer or stationary telephone devices. A user is able to recognize the operation keys by characters, symbols, and numerals displayed in the operation keys by the display devices. The user is able to recognize the operation keys even in a dark location in accordance with the present invention.