Abstract: An image display device includes a display device driving circuit having a scanning signal driving section for outputting display scanning signals according to display data with respect to respective scanning signal lines for displaying an image which is in accordance with the display data with respect to pixels which are disposed in a matrix, and the display device driving circuit includes a control section for controlling the output of the display scanning signals from the scanning signal line driving section to the respective scanning signal lines based on a transition instruction signal for making a transition of output of the display scanning signals to the respective scanning signal lines from successive output to simultaneous output so that the display scanning signals are simultaneously outputted to the plurality of scanning signal lines.

Abstract: Adapting to load currents which differ by more than 100 times between a scanning mode and a hold mode, a frequency of pump operation is decided according to the maximum value of the load currents, and circuit elements of a power supply, for example, such as capacitance of a capacitor for pump operation or a smoothing capacitor, element configurations of switching elements, or capacitance or resistance value of a CR oscillator are set based on this frequency, so that a load current detector lowers the frequency of the pump operation under light load to reduce a self-loss of power in the power supply. This realizes a charge-pump power supply which is installed in a liquid crystal display device of a terminal device of a portable phone, with reduced power consumption under light load and a longer standby time.

Abstract: In a signal line drive circuit of an active-matrix type liquid-crystal display which is a voltage-controlled type display with a capacitive load, n selector switches (161 to 16n) are provided between buffer circuits (151 to 15n) to which voltages responsive to an image to be displayed are inputted from reference voltage selection circuits (131 to 13n), and output terminals (T1 to Tn) to which are connected image signal lines. These selector switches (161 to 16n), based on a shorting control signal (Csh) that is at a high level when the polarity is reversed to perform AC drive of the liquid-crystal panel, switch the output signals (OUT1 to OUTn of the image signal line drive circuit between the output signals of the buffer circuits (151 to 15n) and the common electrode signal (Vcom). By doing this, each of the image signal lines is, for a prescribed time only when the polarity is reversed, separated from the buffer circuits (151 to 15n) and shorted to the common electrode.

Abstract: In an active matrix type display device, a signal voltage is applied from a signal line driving circuit via an active element such as a TFT to display electrodes on a matrix substrate, and a common voltage is applied to a counter electrode on a facing substrate so that the common voltage is shared by respective display cells. A level of the common voltage is switched in every refresh period of a different length. Thus, it is possible to appropriately set a value of the common voltage which is a reference for specifying an effective voltage of positive polarity and an effective voltage of negative polarity according to the refresh periods. As a result, even when the refresh periods of a different length exist in a mixed manner, it is possible to equalize the effective voltage of positive polarity and the effective voltage of negative polarity so as to suppress an occurrence of a flicker.

Abstract: In a display, a first liquid crystal panel has gate bus lines, source bus lines, TFTs, and pixel electrodes, as well as a source driver. A second liquid crystal panel has gate bus lines, source bus lines, TFTs, and pixel electrodes. The source bus lines of the second liquid crystal panel are connected to the associated source bus lines of the first liquid crystal panel through switching TFTs. The source bus lines of the second liquid crystal panel are briefly and repeatedly fed with a predetermined potential when the switching TFTs are off. The invention reduces power consumption of dual panel structure displays and prevents occurrence of an unintended display on the second display panel which is not expected to produce any display.

Abstract: The sub panel 100, having a plurality of gate bus lines 14, source bus lines 16, TFTs 25 and pixel electrodes, is provided with a source driver 15. The main panel 200 has a plurality of gate bus lines 24, source bus lines 16, TFTs 25 and pixel electrodes, each of the source bus lines 16 being connected to the corresponding source bus lines 16 of the first liquid crystal panel 10 through a switching TFT 17. The main panel 200, sharing the source driver 15 with the first liquid crystal panel 10, is less frequently used for display than the first liquid crystal panel 10, and is disconnected by the switching TFT 17 when only the sub panel 100 is used. This makes it possible to device a twin-panel display device low in electric power consumption.

Abstract: A liquid crystal panel (2) includes scanning signal lines (31) for supplying scanning signals to gate electrodes (20) of TFTs (14), and data signal lines (32) for supplying data signals to data electrodes (24) of TFTs. The liquid crystal panel further includes auxiliary capacitive electrode pads (27a) for use in forming auxiliary capacitance and an auxiliary capacitive lines (33) so as not to generate a capacitive bond with the scanning signal lines. The liquid crystal panel is driven at a rewriting frequency of a screen of not more than 30 Hz. As a result, the liquid crystal panel can be driven at a low consumption power while maintaining a desirable display quality of the liquid crystal panel.

Abstract: A semiconductor laser device includes a resonant cavity formed on a GaAs substrate, the resonant cavity including a quantum well (QW) active layer structure having a GaInNAs(Sb) well layer and a pair of barrier layers. The QW structure has a conduction band offset energy (?Ec) equal to or higher than 350 milli-electron-volts (meV) between the well layer and the barrier layers, and each of the barrier layers a tensile strain equal to or lower than 2.5%.

Abstract: An active matrix liquid crystal display drives liquid crystal by writing through TFTs, etc. a source signal from a signal line drive circuit to display electrodes in display cells on a matrix substrate and applying a common signal supplied from a common signal generator to common electrodes on an opposite substrate, the common signal changing in polarity in each frame. After scanning is completed for scan lines corresponding to one frame, a controller controls the interval between scan periods and the cycle of change in polarity of the common signal so as to provide a non-scan period that is longer than the scan period. The provision of the non-scan period extends the duration in which a specified voltage is retained by the display cell. This reduces the effects of variations in retained voltages caused by parasitic capacitance which develops in reflective electrode structures in which the display electrodes partly overlook scan lines and signal lines.

Abstract: A liquid crystal display apparatus and a data driver of the present invention is provided with a sampling pulse generating circuit. The sampling pulse generating circuit is provided with a shift register for shift operation having a plurality of set-reset type flip-flops, and analog switches whose opening and closing of each analog switch is controlled in response to each output of the respective flip-flops so that a clock signal is outputted during the opening as a sampling pulse. Sampling of the image signal is carried out in accordance with the sampling pulses. The pulse width of the sampling pulse varies depending on the duty ratio of the clock signal, thereby ensuring to avoid that active periods of the adjoining sampling pulses overlap with each other.

Abstract: An image display according to the present invention includes a driving device which performs pulse width modulation drive, restrains power consumption, and produces a good multi-tone display. The image display makes the difference between the scan line voltage and the signal line voltage equal in positive polarity writing and negative polarity writing by which pixels are AC driven, so as to make the on-resistances of transistors equal. This allows a maximum pulse width, the size of switching elements, etc. to be determined first so that they match positive polarity writing in which the resistances value of the switching elements rise. No high frequency clock is required to produce subtle differences of charge ratio in negative polarity writing in which the resistances of the switching elements fall. Power consumption which depends on the clock frequency drops too.

Abstract: In a signal line drive circuit of an active-matrix type liquid-crystal display which is a voltage-controlled type display with a capacitive load, n selector switches (161 to 16n) are provided between buffer circuits (151 to 15n) to which voltages responsive to an image to be displayed are inputted from reference voltage selection circuits (131 to 13n), and output terminals (T1 to Tn) to which are connected image signal lines. These selector switches (161 to 16n), based on a shorting control signal (Csh) that is at a high level when the polarity is reversed to perform AC drive of the liquid-crystal panel, switch the output signals (OUT1 to OUTn of the image signal line drive circuit between the output signals of the buffer circuits (151 to 15n) and the common electrode signal (Vcom). By doing this, each of the image signal lines is, for a prescribed time only when the polarity is reversed, separated from the buffer circuits (151 to 15n) and shorted to the common electrode.

Abstract: A semiconductor laser device includes a resonant cavity formed on a GaAs substrate, the resonant cavity including a quantum well (QW) active layer structure having a GaInNAs(Sb) well layer and a pair of barrier layers. The QW structure has a conduction band offset energy (&Dgr;Ec) equal to or higher than 350 milli-electron-volts (meV) between the well layer and the barrier layers, and each of the barrier layers a tensile strain equal to or lower than 2.5%.

Abstract: A liquid crystal panel (2) includes scanning signal lines (31) for supplying scanning signals to gate electrodes (20) of TFTs (14), and data signal lines (32) for supplying data signals to data electrodes (24) of TFTs. The liquid crystal panel further includes auxiliary capacitive electrode pads (27a) for use in forming auxiliary capacitance and an auxiliary capacitive lines (33) so as not to generate a capacitive bond with the scanning signal lines. The liquid crystal panel is driven at a rewriting frequency of a screen of not more than 30 Hz. As a result, the liquid crystal panel can be driven at a low consumption power while maintaining a desirable display quality of the liquid crystal panel.

Abstract: An active matrix liquid crystal display drives liquid crystal by writing through TFTs, etc. a source signal from a signal line drive circuit to display electrodes in display cells on a matrix substrate and applying a common signal supplied from a common signal generator to common electrodes on an opposite substrate, the common signal changing in polarity in each frame. After scanning is completed for scan lines corresponding to one frame, a controller controls the interval between scan periods and the cycle of change in polarity of the common signal so as to provide a non-scan period that is longer than the scan period. The provision of the non-scan scan period extends the duration in which a specified voltage is retained by the display cell. This reduces the effects of variations in retained voltages caused by parasitic capacitance which develops in reflective electrode structures in which the display electrodes partly overlook scan lines and signal lines.

Abstract: An n-type modulation-doped multi quantum well semiconductor laser device having a multi quantum well structure composed of a hetero-junction structure including well layers and barrier layers, characterized in that each of the well layers and each of the barrier layers are formed of an undoped semiconductor material and a semiconductor material modulation-doped with an n-type dopant, respectively, an anti-reflection film and a high-reflection film are formed on the front and rear facets, respectively, the resonator length is not shorter than 800 &mgr;m, and mirror loss (&agr;m) given by &agr;m=(1/2L)ln{1/(Rf×Rr)}, where L, Rf and Rr are the cavity length (cm), reflectance of the front facet, and reflectance of the rear facet, respectively, is not higher than 15 cm−1. The output of this laser device is higher than that of a conventional undoped MQW semiconductor laser device.

Abstract: In an active matrix type display device, a signal voltage is applied from a signal line driving circuit via an active element such as a TFT to display electrodes on a matrix substrate, and a common voltage is applied to a counter electrode on a facing substrate so that the common voltage is shared by respective display cells. A level of the common voltage is switched in every refresh period of a different length. Thus, it is possible to appropriately set a value of the common voltage which is a reference for specifying an effective voltage of positive polarity and an effective voltage of negative polarity according to the refresh periods. As a result, even when the refresh periods of a different length exist in a mixed manner, it is possible to equalize the effective voltage of positive polarity and the effective voltage of negative polarity so as to suppress an occurrence of a flicker.

Abstract: Adapting to load currents which differ by more than 100 times between a scanning mode and a hold mode, a frequency of pump operation is decided according to the maximum value of the load currents, and circuit elements of a power supply, for example, such as capacitance of a capacitor for pump operation or a smoothing capacitor, element configurations of switching elements, or capacitance or resistance value of a CR oscillator are set based on this frequency, so that a load current detector lowers the frequency of the pump operation under light load to reduce a self-loss of power in the power supply. This realizes a charge-pump power supply which is installed in a liquid crystal display device of a terminal device of a portable phone, with reduced power consumption under light load and a longer standby time.

Abstract: The signal line drive circuit is provided with: a reference voltage chooser circuit for choosing one of incoming voltages in accordance with tones represented by an image signal to output the chosen voltage as a signal line drive signal; and a reference voltage line for directly transmitting first reference voltages VB1 (inclusive of a maximum voltage value VB1max and a minimum voltage value VB1min) supplied by an external reference power supply circuit to the reference voltage chooser circuit. The arrangement eliminates the need to provide a buffer circuit to a reference voltage line over which the first reference voltage is directly transmitted, thereby reducing that electric current which would otherwise flow through the buffer circuit.

Abstract: A drive circuit for use in a liquid crystal display supplies source signals from a source driver to pixel electrodes through switching by means of TFTs according to scan signals from a gate driver, includes a reference voltage generator circuit for adjusting potential differences between the pixel electrodes and a common electrode so as to compensate for the effects of variations in drain voltages caused by parasitic capacity in the TFTs and compensate for irregularities in DC voltage caused by asymmetry in properties between an active matrix substrate and an opposite substrate sandwiching a liquid crystal layer. The reference voltage generator circuit is composed of a reference voltage generator circuit for shifting the voltage levels of the source signals supplied by the source driver equally for all the pixel electrodes.