Abstract: A level shifter 13 is provided for each of SR flip flops F1 constituting a shift register 11. The level shifter 13 increases a voltage of a clock signal CK. This arrangement reduces a distance for transmitting a clock signal whose voltage has been increased, as compared with a construction in which a voltage of a clock signal is increased by a single level shifter and the signal is transmitted to each of the flip flops; consequently, a load capacity of the level shifter can be smaller. Furthermore, each of the level shifters is operated during a pulse output of the previous level shifter 13, and the operation is suspended at the end of the pulse output. Thus, the level shifters 13 can operate only when it is necessary to apply a clock signal CK to the corresponding SR flip flop F1. As a result, even when an amplitude of a clock signal is small, it is possible to reduce power consumption of the shift resister under normal operation.

Abstract: In each horizontal period, by switching ON switches respectively provided for three data signal lines for R, G and B in a group at the same time only in a predetermined period, the data signal lines in the group are preliminary charged to a predetermined potential at the same time before a data signal supply period. In a subsequent data signal supply period, respective switches of data signal lines for R, G and B are switched ON sequentially, to sequentially supply respective data for R, G and B to pixels on a scanning signal line as selected are supplied via data signal lines. As a result, in a display device driven by time-division based on a group of sequentially provided data signal lines, it is possible to suppress up-throw potential fluctuations when display.

Abstract: A shift register circuit includes a plurality of latch circuits connected in series to sequentially transfer a pulse signal ST from one to another, a clock signal line transmitting a clock signal CLK, and a plurality of switching circuits performing electrical connection and disconnection between the clock signal line and the plurality of latch circuits. Upon turning on the shift register, at least one of the switching circuits electrically disconnects at least one of the latch circuits from the clock signal line. During an initialization period immediately after power has been turned on, the frequency of the clock signal CLK is lower than in a normal operation period and gradually increases toward the frequency used in the normal operation period.

Abstract: An image display device of this invention includes a pre-charging voltage stabilizing section having current controlling means and charge holding means which respectively include a resistor and a capacitor to stabilize a pre-charging voltage. The charge holding means holds a voltage to be supplied to data signal lines, and the current controlling means suppresses a current flow from a control signal generating circuit, thereby suppressing power fluctuation at the control signal generating circuit. This suppresses fluctuation in the pre-charging voltage and enables data signal lines to be charged to a predetermined voltage, thereby suppressing deterioration of image quality and an increase in power consumption of the image display device.

Abstract: A CMOS logical circuit comprises two electric current paths each of which has circuits consisting of n-type and p-type transistors. In a circuit consisting of n-type or p-type transistors, one electric current path is provided with a circuit having the same construction as that of a circuit having an n-type transistor of a CMOS logical circuit outputting a logical operation result similar to that of this logical circuit, and the other electric current path is provided with a circuit having the same construction as that of a circuit having a p-type transistor of the CMOS logical circuit outputting a logical operation result similar to that of this logical circuit. In another circuit consisting of the other channel type, a gate electrode of the transistor provided on the one electric current path and that of the transistor provided on the other electric current path are connected to drain electrodes of the counterparts.

Abstract: A shift register includes control circuits CNi (i=1 through n) corresponding to respective blocks, and a level shifter LSi+1 of the next stage is controlled by one of the outputs of the shift register and one of the outputs of flip-flops Fi. With this, a level shifter of the present stage operates only for a period minimum for outputting the shift output from the present block, so that the power consumption is reduced, Furthermore, it is possible to cause the outputs SL1 through SLn not to overlap each other.

Abstract: A digital-to-analog conversion circuit of charge distribution type includes a plurality of capacitors having respective capacitances that increase in a sequential order, one end of the capacitors being commonly connected electrically. The circuit also includes a plurality of analog switches each for electrically connecting a reference potential corresponding to a digital signal inputted from outside to the other end of the corresponding capacitor. These analog switches have respective driving capacities that increase in a sequential order.

Abstract: The present invention includes: a shift register section, including multiple-stage flip-flops operating in synchronism with a clock signal, for switching a shift direction in accordance with an externally supplied direction instruct signal; a waveform change section for changing in waveform a signal output of one of the flip-flops which is in a first predetermined stage; and an inspection signal switching section for switching, in accordance with the direction instruct signal, an output between the signal output which has been changed in waveform in the waveform change section and a signal output of one of the flip-flops which is in a second predetermined stage.

Abstract: A precharge control circuit constituted by (1) a latch circuit mounted in a precharge circuit and (2) a level shifter circuit of a current drive type controlled through an output of the latch circuit is included. The precharge control circuit changes the latch circuit to an active state to cause the level shifter circuit of a current drive type to operate only during a precharge period and also during immediately preceding and succeeding periods, and outside these periods, changes the latch circuit in a non-active state and the level shifter circuit of a current drive type in an operating state to save power consumption in the level shifter circuit. This enables a low-power-consuming precharge circuit, as well as a low-power-consuming image display device with a high quality display capability, to be offered.

Abstract: A shift register is provided with a shift register section composed of a plurality of stages of flip-flops that operate in synchronization with a clock signal, and level shifters for boosting a start signal lower than a driving voltage and for applying the same to both ends of the shift register section, and the shift register is capable of switching the shift direction in accordance with the switching signal. The foregoing level shifters are current-driving-type level shifters that can operate even in the case where the transistor characteristics are inferior or in the case of fast operations, and that can carry out level shifting even with a start signal having a small amplitude. Furthermore, the foregoing level shifters are provided at both ends of the shift register section, respectively, and one of the same stops operating in accordance with a switching signal, so that consumed power should decrease.

Abstract: In a shift register provided with flip-flops that operate in synchronism with a clock signal, and a switching means, which is opened and closed in response to an output of the preceding stage of each of the flip-flops, is installed. The clock signal is selectively inputted by the switching means, and the selected clock signal is inverted and used as a shift register output from each of the stages. Moreover, two kinds of clock signals, each of which has a duty ratio of not more than 50% and which have no overlapped portions in their low-level periods, are used so as to prevent the outputs of the shift-register from overlapping each other. Thus, it is possible to provide a shift register which is preferably used for a driving circuit of an image display device, can miniaturize the driving circuit, and can desirably change the pulse width of the output signal, and also to provide an image display device using such a shift register.

Abstract: The data signal line driving circuit of the present invention is arranged so that data signal line groups, each of which is made up of two data signal lines sequentially disposed, are connected to two video signal lines, each of which allows a two-phased video signal to be forwarded. A shift resister SR, a drive switching circuit, and a waveform shaping circuit, that constitute a video signal fetching section, collect the data signal line groups via the two video signal lines as a single block. At this time, the data signal lines are respectively driven so as to fetch the video signal from the video signal lines into the data signal lines of the data signal line groups in each block. Thus, in performing multiphase development, it is possible to provide the data signal line driving circuit which can reduce power consumption in low resolution driving compared with a case of high resolution driving.

Abstract: In a structure in which a plurality of signals related to each other are supplied to a driving circuit in such a manner that at least one of the signals is supplied also to the other circuit, the present invention prevents change of phase relation between the plural signals due to difference in wiring load, without directly processing the signals with higher power consumption. The first and second clock signals SCK1 and SCK2 are supplied to the first data signal line driving circuit SD1, while the first clock signal SCK1 is also supplied to the second data signal line driving circuit SD2 in parallel. The wirings 1 and 2 for the respective signals are adjusted to have equal wiring load with a dummy wiring 2 provided in the wiring 2, for solving uneven wiring load caused by difference of leading manner, the dummy wiring 2 constituting an additional capacitor section 7, together with a liquid crystal layer and a counter electrode.

Abstract: The subject invention discloses a scanning direction control circuit, which includes a bidirectional shift register in which shifting direction is switched in accordance with a switching signal L/R, which is step-upped by a level shifter when having lower amplitude than the driving voltage. The scanning direction control circuit includes a latch circuit between the level shifter and the bidirectional shift register, and a control circuit causes the latch circuit to carry out latching operation after shifting operation of flip-flops constituting the bidirectional shift register is completed in response to output signals of the flip-flops. The control circuit brings the level shifter into active state in a period before, at and after the latching timing, and brings the level shifter into inactive state in the remaining period. With this arrangement, the switching signal L/R can be supplied at a predetermined timing regardless of external input timing thereof, with low power consumption.

Abstract: In a shift register block according to the present invention, a plurality of flip-flops F/F(1), F/F(2), . . . F/F(n) constitute a shift register SR, and each adjacent ones of these flip-flops are therebetween having a corresponding one of waveform processing circuits WR(1) through WR(n), so that the shift register SR and the waveform processing circuits WR(1) and WR(n) are linearly aligned. With such an arrangement, it is possible to reduce area occupied by a signal line driving circuit including the sift register block, thereby narrowing the frame area of a display device.

Abstract: A shift register is provided with a shift register section composed of a plurality of stages of flip-flops that operate in synchronization with a clock signal, and level shifters for boosting a start signal lower than a driving voltage and for applying the same to both ends of the shift register section, and the shift register is capable of switching the shift direction in accordance with the switching signal. The foregoing level shifters are current-driving-type level shifters that can operate even in the case where the transistor characteristics are inferior or in the case of fast operations, and that can carry out level shifting even with a start signal having a small amplitude. Furthermore, the foregoing level shifters are provided at both ends of the shift register section, respectively, and one of the same stops operating in accordance with a switching signal, so that consumed power should decrease.

Abstract: In a shift register provided with flip-flops that operate in synchronism with a clock signal, and a switching means, which is opened and closed in response to an output of the preceding stage of each of the flip-flops, is installed. The clock signal is selectively inputted by the switching means, and the selected clock signal is inverted and used as a shift register output from each of the stages. An output pulse having the same width as the pulse of the clock signal is generated.

Abstract: The surface area occupied by a digital type signal line driver circuit in an image display device is large, and this is an impediment to reducing the size of the display device. A memory circuit within a signal line driver circuit is made common among n signal lines (where n is a natural number greater than or equal to 2). One horizontal scan period is divided into n divisions, and all signal lines can be driven by performing processing with respect to signal lines differing by memory circuit and D/A converter circuit, respectively, during the period of each division. It thus becomes possible to make 1/n as many memory circuits and D/A conversion circuits within the signal line driver circuit as in a conventional example.

Abstract: A data signal line drive circuit is provided with: a shift register belonging to a system, whose stages correspond to respective sampling units for driving odd-number-th data signal lines; and a shift register belonging to another system, whose stages correspond to respective sampling units for driving even-number-th data signal lines. On the occasion of low-resolution mode, only either of the shift registers is operated, and in accordance with the outputs from the respective stages of the shift register which has been operated, timing signals, which are supplied to the sampling units corresponding to the stages of both shift registers, are generated. With this arrangement, even if one of input signals each having different signal line resolution is inputted, a signal line drive circuit which consumes a small amount of electric power can be realized, while it is possible to specify the timings of the operation of signal line drive sections for driving signal lines, in accordance with the input signal.

Abstract: A driver circuit for a display device includes a plurality of set-reset flip-flops and switch circuits, and is arranged so that a timing pulse for sampling outputted from the flip-flop is supplied to the switch circuit, so as to cause the switch circuit to receive a clock signal. The clock signal operates as a set signal of the next stage flip-flop and outputted as a control signal for carrying out pre-charging of a data signal line and a selected pixel connected to the data signal line, with a switch. Thus, in case of performing pre-charging of a signal supplying line with an internal pre-charging circuit by using a pre-charging power source having small driving ability, this arrangement can provide a driver circuit for a display device capable of preventing fluctuation of a signal supplied to a different signal supplying line, while keeping the circuit scale of the shift register small.