JP2008233925A - Method for driving display device, display device using same and portable device mounted with display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To drive a matrix type display device while sufficient power reduction and high display quality sufficiently suppressive in flickering are made compatible. <P>SOLUTION: In a pause period T2, the potentials of data signal lines and a counter electrode of a liquid crystal panel are made almost equal to the respective centers of the voltage amplitudes in a scanning period T1. Thus, the effective voltages applied to the liquid crystal layer are almost equalized both in the scanning period T1 and the pause period T2. Moreover, in the pause period T2, AC-driving of the counter electrode is stopped first (point d), and then a source driver is brought into high impedance state (point 3). Thus, a steady-state current flowing through an amplifier in the source driver in the pause period T2 can be reduced. Therefore, low power consumption can be achieved while keeping favorable display quality by eliminating the flickers generated in each scanning period T1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to low power consumption of a matrix display device.

  In recent years, application of liquid crystal display devices to word processors, laptop personal computers, pocket televisions, and the like is rapidly progressing. In particular, a reflective liquid crystal display device that displays light by reflecting light incident from the outside among liquid crystal display devices does not require a backlight, so it consumes less power, is thin, and can be reduced in weight. Attention has been paid.

  Conventional reflective liquid crystal display devices can be used for segment display systems that can display only simple numbers and pictograms used in watches and the like, as well as complex displays such as personal computers and portable information terminals. As a thing, it is divided roughly into a simple multiplex drive system and an active matrix drive system using an active element such as a TFT (thin film transistor). It is desirable to reduce power consumption in each method.

  Among the matrix type liquid crystal display devices, those of the simple multiplex drive type are basically 2 sized and have a sufficiently low power consumption of about 10 mW to 15 mW, but are basically low in brightness and contrast and low in response speed. There is a problem with the display quality. On the other hand, in the active drive method using TFT or the like, the brightness and contrast are high, the response speed is large and the basic display quality is sufficient, but the peripheral drive circuit is complicated, so the power consumption is about 2 type. Even the size was about 100 mW to 150 mW, which was not satisfactory.

  On the other hand, research and development for sufficiently low power consumption and good display quality have been energetically performed so far.

  For example, SID '95 Proceedings p249-p252 and published patent publication "Japanese Patent Laid-Open No. 3-271895 (published date: December 3, 1991)" describe a technique for reducing the power consumption of a TFT liquid crystal driver. As a result, a multi-field driving method has been proposed. This is because the scanning of one screen is divided into a plurality of times every other scanning signal line or every other scanning signal line, and the polarity of the voltage of the data signal line is not reversed during one scanning. The power consumption of the line driver is reduced. Another object of the present invention is to realize a display without flickering as a whole by offsetting the change in brightness, i.e. flickering, generated in each line with the flickering of adjacent lines of opposite polarity.

Further, for example, a ferroelectric liquid crystal is used for the liquid crystal panel as in a method disclosed in a published patent publication “Japanese Patent Laid-Open No. 6-342148 (published date: December 13, 1994)”. There is also a method of reducing power consumption by providing memory characteristics and reducing the drive frequency (refresh rate).
Japanese Patent Laid-Open No. 3-271895 (Publication date: December 3, 1991) JP-A-6-342148 (publication date: December 13, 1994) H. Okumura, G. Ito (Toshiba R & D Center, Yokohama, Japan) SID '95 Proceedings p249-p252, May 21, 1995

  However, even if multi-field driving is performed, flickering occurs for each line, and flickering is actually perceived even if offset by adjacent lines, and the visibility is significantly reduced. In addition, the drive frequency is only slightly reduced, and the reduction in power consumption is not sufficient. Further, in the multi-field driving method, since one screen is divided into a plurality of subfields and scanning is performed every other line or every other scanning signal line, an image is temporarily stored in a frame memory and then driven to scan. It is necessary to read a signal corresponding to the signal line, and the circuit configuration is inevitably complicated. Therefore, there is a drawback that the peripheral circuit is enlarged and the cost is increased.

  Further, in the method disclosed in “JP-A-6-342148”, since the ferroelectric liquid crystal is basically a binary (monochrome) display, gradation display cannot be performed, and a natural image cannot be displayed. . In addition, in order to make a ferroelectric liquid crystal into a panel, an advanced panel production technique is required, so that it is difficult to realize it and has not been put into practical use until today.

  As described above, in the driving method of the conventional matrix type liquid crystal display device, sufficient power consumption can be easily reduced while satisfying basic display quality such as brightness, contrast, response speed, and gradation. I couldn't. Furthermore, the conventional driving method of the matrix type liquid crystal display device cannot achieve both a sufficiently low power consumption and a high display quality without flickering. These problems are not limited to liquid crystal display devices, but can also be said for matrix display devices in general.

  The present invention has been made to solve the above-described problems, and its purpose is to provide a matrix type display capable of achieving both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed. An object of the present invention is to provide a method for driving a device, a display device using the method, and a portable device equipped with the display device.

  In order to solve the above-described problem, the display device driving method of the present invention selects and scans each scanning signal line on a screen in which pixels are arranged in a matrix, and outputs data signals to the pixels on the selected line. In a driving method of a display device that performs display by supplying a data signal from a line, following a scanning period for scanning one screen, a pause period is provided in which all scanning signal lines are in a non-scanning state longer than the scanning period, In addition, when the potential of the data signal line is fixed to a predetermined data signal line pause potential during the pause period, the predetermined data signal line pause potential is set to the data signal line supplied to the data signal line during the scan period. It is characterized by being set at the center of amplitude.

  In the driving method of the display device of the present invention, the potential of the counter electrode may be fixed to a predetermined counter electrode pause potential during the pause period.

  In the driving method of the display device of the present invention, the counter electrode rest potential of the counter electrode in the rest period may be set within the voltage range of the counter electrode drive signal supplied to the counter electrode in the scan period.

  According to the above method, the data signal line driver (source driver) that increases in direct proportion to the supply frequency of the data signal is provided by providing a rest period longer than the scanning period as the non-scanning period after the scanning period for rewriting one screen. Power consumption can be easily reduced.

  Further, by fixing the potential of the data signal line in the pause period to the data signal line pause potential, the potential of the data signal line in the pause period can be optimally controlled. That is, the influence of the potential of the data signal line on the pixel electrode can be made substantially equal in the scanning period and the pause period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The data signal line pause potential that fixes the potential of the data signal line in the pause period is set to the amplitude center of the data signal supplied to the data signal line in the scan period.

  In the case of an active matrix liquid crystal display device, practically flicker-free display can be realized even when the potential of the data signal line in the pause period is changed within the range of the amplitude center ± 1.5 V in the scanning period.

  Further, in order to solve the above-described problem, the display device driving method of the present invention selects and scans each scanning signal line on the screen in which pixels are arranged in a matrix, and the pixels on the selected line are scanned. In a driving method of a display device that performs display by supplying a data signal from a data signal line, a rest period in which all the scanning signal lines are in a non-scanning state is longer than the scanning period, following a scanning period for scanning one screen. And when the potential of the counter electrode is fixed to a predetermined counter electrode pause potential during the pause period, the predetermined counter electrode pause potential is set to the amplitude of the counter electrode drive signal supplied to the counter electrode during the scanning period. It is characterized by being set at the center.

  In the driving method of the display device of the present invention, the potential of the counter electrode may be fixed to a predetermined counter electrode pause potential during the pause period.

  In the driving method of the display device of the present invention, the counter electrode rest potential of the counter electrode in the rest period may be set within the voltage range of the counter electrode drive signal supplied to the counter electrode in the scan period.

  Even when the counter electrode is AC driven to reduce the amplitude of the output voltage of the data signal driver by the above method, a non-scanning period longer than the scanning period after the scanning period for rewriting one screen Thus, the power consumption of the counter electrode driver (common driver) that increases in direct proportion to the supply frequency of the data signal can be easily reduced.

  In addition, by fixing the potential of the counter electrode in the rest period to the counter electrode rest potential, the potential of the counter electrode in the rest period can be optimally controlled. That is, the influence of the potential of the counter electrode on the pixel electrode can be made almost equal in the scanning period and the rest period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The counter electrode pause potential that fixes the potential of the counter electrode during the pause period is set to the amplitude center of the counter electrode drive signal supplied to the counter electrode during the scanning period.

  Note that, in the case of an active matrix liquid crystal display device, a practically flicker-free display can be realized even if the potential of the counter electrode in the pause period is changed within the range of the amplitude center ± 1.0 V in the scanning period.

  In addition, in order to solve the above-described problem, the display device driving method of the present invention fixes the potential of the data signal line to the data signal line resting potential in the resting period, and the counter electrode in the resting period. It is characterized in that the potential is fixed to the counter electrode rest potential.

  By the above method, a non-scanning period longer than the scanning period is provided after the scanning period for rewriting one screen, so that the frequency increases in direct proportion to the frequency of the drive signal supplied to the data signal line and the counter electrode. Power consumption can be easily reduced.

  Further, by fixing the potentials of the data signal line and the counter electrode in the pause period to the data signal line pause potential and the counter electrode pause potential, respectively, the potentials of the data signal line and the counter electrode in the pause period can be optimally controlled. It becomes possible. That is, the influence of the potential of the data signal line and the counter electrode on the pixel electrode can be made almost equal in the scanning period and the rest period. Here, the data signal line rest potential and the counter electrode rest potential may be set so that the effective voltage between the pixel electrode and the counter electrode is substantially equal between the scanning period and the rest period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  In order to solve the above-described problem, the display device driving method of the present invention is configured such that, in the pause period, the potential of the data signal line and the potential of the counter electrode are set to a data signal line pause potential and a counter electrode pause potential. Then, the data signal line is set to a high impedance state with respect to the data signal driver that supplies the data signal to the data signal line.

  By the above method, all the data signal lines are further disconnected from the data signal driver during the idle period so that the data signal driver is in a high impedance state, so that the potential of each data signal line is kept constant during the idle period. can do.

  Accordingly, each variation caused by the potential variation of the data signal line such as the potential variation of the pixel electrode caused by capacitive coupling between the data signal line and the pixel electrode, which occurs in the display device having the pixel electrode connected to the data signal line. The change in the data holding state of the pixel is suppressed, and the flickering of the screen is sufficiently suppressed.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

Further, in order to solve the above-described problem, the display device driving method of the present invention selects and scans each scanning signal line on the screen in which pixels are arranged in a matrix, and the pixels on the selected line are scanned. In a driving method of a display device that performs display by supplying a data signal from a data signal line, a rest period in which all the scanning signal lines are in a non-scanning state is longer than the scanning period, following a scanning period for scanning one screen. In the pause period, a DC drive signal of the predetermined counter electrode pause potential set at the amplitude center of the counter electrode drive signal supplied to the counter electrode during the scanning period is applied to the counter electrode. At the same time, the DC drive signal is also applied to the data signal line.

  By the above method, a non-scanning period longer than the scanning period is provided after the scanning period for rewriting one screen, so that the frequency increases in direct proportion to the frequency of the drive signal supplied to the data signal line and the counter electrode. Power consumption can be easily reduced.

  Further, the data signal line and the counter electrode are driven with the DC drive signal having the predetermined counter electrode pause potential set at the amplitude center of the counter electrode drive signal supplied to the counter electrode during the scanning period in the pause period. Thus, it is possible to optimally control the potential difference between the data signal line and the counter electrode during the pause period. That is, the influence of the potential of the data signal line and the counter electrode on the pixel electrode can be made substantially equal in the scanning period and the rest period.

  Therefore, since the amplitude and phase of the drive signal supplied to the data signal line and the counter electrode coincide in the pause period, even if the pause period is provided, the effective value of the potential of the pixel electrode is made substantially constant, and display without flicker is achieved. realizable.

  In addition, since the drive signal of the data signal line can be supplied from the AC signal generation circuit (common driver) that supplies the drive signal to the counter electrode in the idle period, the data signal driver is disconnected from the data signal line during the idle period. The power consumption can be reduced by separating and suspending the data signal driver.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  In the case of an active matrix liquid crystal display device, a practically flicker-free display can be realized even when the potentials of the data signal line and the counter electrode in the pause period are changed within a range of the amplitude center of ± 1.0 V in the scanning period. .

  In order to solve the above-described problems, a display device according to the present invention includes a control unit that executes the above-described driving method.

  With the above structure, it is possible to achieve both low power consumption and high display quality in which flicker is sufficiently suppressed in a matrix display device. For example, according to a liquid crystal display device, low power consumption can be achieved while maintaining good display quality in a configuration having active elements.

  In order to solve the above-described problems, the portable device of the present invention is equipped with the display device.

  As described above, the driving method of the display device of the present invention selects and scans each scanning signal line on the screen in which the pixels are arranged in a matrix, and the data signal is transmitted from the data signal line to the pixels of the selected line. In the method of driving a display device that supplies a display, a pause period in which all the scanning signal lines are in a non-scanning state is provided longer than the scan period, following the scan period for scanning one screen, and the pause is performed. When the potential of the data signal line is fixed to a predetermined data signal line pause potential during the period, the predetermined data signal line pause potential is set to the amplitude center of the data signal supplied to the data signal line during the scanning period. It is a method to do.

  According to the above method, the data signal line driver (source driver) that increases in direct proportion to the supply frequency of the data signal is provided by providing a rest period longer than the scanning period as the non-scanning period after the scanning period for rewriting one screen. Power consumption can be easily reduced.

  Further, by fixing the potential of the data signal line in the pause period to the data signal line pause potential, the potential of the data signal line in the pause period can be optimally controlled. That is, the influence of the potential of the data signal line on the pixel electrode can be made substantially equal in the scanning period and the pause period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The data signal line pause potential that fixes the potential of the data signal line in the pause period is set to the amplitude center of the data signal supplied to the data signal line in the scan period.

  In the case of an active matrix liquid crystal display device, practically flicker-free display can be realized even when the potential of the data signal line in the pause period is changed within the range of the amplitude center ± 1.5 V in the scanning period.

  Further, as described above, the driving method of the display device of the present invention selects and scans each scanning signal line of the screen in which the pixels are arranged in a matrix, and the data signal line is applied to the pixels of the selected line. In a method for driving a display device that performs display by supplying a data signal, following a scanning period for scanning one screen, a pause period is provided in which all scanning signal lines are in a non-scanning state longer than the scanning period; and In the case where the potential of the counter electrode is fixed to a predetermined counter electrode pause potential during the pause period, the predetermined counter electrode pause potential is set to the amplitude center of the counter electrode drive signal supplied to the counter electrode during the scanning period. Is the method.

  Even when the counter electrode is AC driven to reduce the amplitude of the output voltage of the data signal driver by the above method, a non-scanning period longer than the scanning period after the scanning period for rewriting one screen Thus, the power consumption of the counter electrode driver (common driver) that increases in direct proportion to the supply frequency of the data signal can be easily reduced.

  In addition, by fixing the potential of the counter electrode in the rest period to the counter electrode rest potential, the potential of the counter electrode in the rest period can be optimally controlled. That is, the influence of the potential of the counter electrode on the pixel electrode can be made almost equal in the scanning period and the rest period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The counter electrode pause potential that fixes the potential of the counter electrode during the pause period is set to the amplitude center of the counter electrode drive signal supplied to the counter electrode during the scanning period.

  Note that, in the case of an active matrix liquid crystal display device, a practically flicker-free display can be realized even if the potential of the counter electrode in the pause period is changed within the range of the amplitude center ± 1.0 V in the scanning period.

  According to the above, a driving method of a matrix type display device capable of achieving both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed, a display device using the same, and a display device thereof The effect of providing the mounted portable device is achieved.

  The embodiment of the present invention will be described with reference to FIGS. 1 to 13 as follows.

  In the following embodiments, an active matrix liquid crystal display device will be described as an example of a display device driving method and a display device using the same according to the present invention. However, the present invention is not limited to this, and can also be applied to an EL (electroluminescence) display device that performs addressing using TFT elements. The display device can be mounted on a mobile phone, a pocket game machine, a PDA (personal digital assistants), a mobile TV, a remote control, a notebook personal computer, and other mobile terminals. These portable devices are often driven by a battery and can be driven for a long time by mounting a display device that can reduce power consumption while maintaining good display quality without flickering.

  FIG. 6 shows a system block diagram of a liquid crystal display device (display device) 1 as a display device according to the present embodiment. The liquid crystal display device 1 is a reflective liquid crystal display device, and includes a liquid crystal panel (screen) 2, a gate driver 3, a source driver (data signal driver) 4, a control (control means) IC 5, an image memory 6, and a common driver 7. It is prepared for.

  As shown in FIG. 7, the liquid crystal panel 2 includes a screen composed of pixels arranged in a matrix, a plurality of scanning signal lines for selecting and scanning the screen in a line-sequential manner, and pixels on the selected line. And a plurality of data signal lines for supplying data signals. The scanning signal line and the data signal line are orthogonal to each other.

  Here, a specific configuration example of the liquid crystal panel 2 will be described with reference to FIGS. 8 and 9. 8 is a cross-sectional view taken along line AA in FIG. FIG. 9 is a plan view showing the configuration of the liquid crystal layer 13 and the subsequent parts shown in FIG.

  As shown in FIG. 8, the liquid crystal panel 2 is a reflective active matrix liquid crystal panel, and a liquid crystal layer 13 such as a nematic liquid crystal is sandwiched between two glass substrates 11 and 12, and active elements are formed on the glass substrate 12. The TFTs 14 are formed in a basic configuration. In this embodiment, a TFT is used as an active element, but an MIM (metal insulator metal) or an FET other than a TFT can also be used. On the upper surface of the glass substrate 11, a phase difference plate 15, a polarizing plate 16, and an antireflection film 17 for controlling the state of incident light are provided in this order. On the lower surface of the glass substrate 11, an RGB color filter 18 and a transparent common electrode (counter electrode) 19 as a counter electrode are provided in this order. The color filter 18 enables color display.

In each TFT 14, a part of the scanning signal line provided on the glass substrate 12 is used as a gate electrode 20, and a gate insulating film 21 is formed thereon. An i-type amorphous silicon layer 22 is provided at a position facing the gate electrode 20 with the gate insulating film 21 interposed therebetween, and two n ⁺ -type amorphous silicon layers 23 are formed so as to sandwich the channel region of the i-type amorphous silicon layer 22. ing. The upper surface of one n ⁺ -type amorphous silicon layer 23 data electrode 24 forming a part of the data signal lines are formed, the drain over the flat upper surface of the gate insulating film 21 from the upper surface of the other n + -type amorphous silicon layer 23 The electrode 25 is formed by being drawn out. As shown in FIG. 9, one end of the drain electrode 25 on the side opposite to the extraction start position is connected to a rectangular auxiliary capacitance electrode pad 27a facing the auxiliary capacitance wiring 33. An interlayer insulating film 26 is formed on the upper surface of the TFTs 14, and reflective electrodes 27 b are provided on the upper surface of the interlayer insulating film 26. The reflective electrodes 27b are reflective members for performing reflective display using ambient light. In order to control the direction of light reflected by the reflective electrodes 27b, fine irregularities are formed on the surface of the interlayer insulating film 26.

  Further, each reflective electrode 27 b is electrically connected to the drain electrode 25 through a contact hole 28 provided in the interlayer insulating film 26. That is, the voltage applied from the data electrode 24 and controlled by the TFT 14 is applied from the drain electrode 25 to the reflective electrode 27b through the contact hole 28, and the liquid crystal layer is applied by the voltage between the reflective electrode 27b and the transparent common electrode 19. 13 is driven. That is, the auxiliary capacitor electrode pad 27 a and the reflective electrode 27 b are electrically connected to each other, and liquid crystal is interposed between the reflective electrode 27 b and the transparent common electrode 19. As described above, the auxiliary capacitor electrode pad 27 a and the reflective electrode 27 b constitute the pixel electrode 27. In the case of a transmissive liquid crystal display device, pixel electrodes arranged so as to correspond to the electrodes are transparent electrodes.

  Further, as shown in FIG. 9 in which a portion below the liquid crystal layer 13 in FIG. 8 is viewed from above, the liquid crystal panel 2 includes a scanning signal line 31 for supplying a scanning signal to the gate electrode 20 of the TFT 14 and the TFT 14. The data signal lines 32 for supplying data signals to the data electrodes 24 are provided on the glass substrate 12 so as to be orthogonal to each other. Further, auxiliary capacity wirings 33 as auxiliary capacity electrodes for forming auxiliary capacity of the pixels are provided between the auxiliary capacity electrode pads 27a. The auxiliary capacitance wirings 33 are located on the glass substrate 12 at positions other than the scanning signal lines 31 and are partially paired with the auxiliary capacitance electrode pads 27a with the gate insulating film 21 interposed therebetween. It is provided in parallel. Not only in this case, the auxiliary capacitance lines 33... Need only be provided avoiding the positions of the scanning signal lines 31. In the figure, the reflective electrodes 27b are partially omitted so that the positional relationship between the auxiliary capacitance electrode pads 27a and the auxiliary capacitance wirings 33 is clarified. Further, the irregularities on the surface of the interlayer insulating film 26 in FIG. 8 are not shown in FIG. In the present embodiment, the panel size of the liquid crystal panel 2 is described as a diagonal of 0.1 m, the scanning signal lines 31 are 240 lines, and the data signal lines are 320 × 3 lines.

Further, FIG. 10 shows an equivalent circuit for one pixel in the liquid crystal panel 2 having the above configuration. As shown in FIG. 10, the gate insulating film 21 is composed of the liquid crystal capacitor _CLC formed by sandwiching the liquid crystal layer 13 between the transparent common electrode 19 and the reflective electrode 27b, the auxiliary capacitor electrode pad 27a, and the auxiliary capacitor wiring 33. with the auxiliary capacitance C _CS formed by sandwiching connected to TFT14 to DC via a buffer (not shown) to the storage capacitor wiring 33 of the transparent common electrode 19 and the auxiliary capacitance C _CS of the liquid crystal capacitance C _LC Alternatively, an AC common electrode voltage _VCOM is applied.

Subsequently, the control IC (control means) 5 shown in FIG. 6 receives the image data stored in the image memory 6 inside a computer or the like, and receives the gate start pulse signal GSP and the gate clock to the gate driver 3. The signal GCK is distributed, and RGB gradation data, the source start pulse signal SSP, the source latch strobe signal SLS, and the source clock signal SCK are distributed to the source driver 4. All these signals are synchronized, and when the frequency of each signal is expressed by adding f in front of the signal name, the relationship between these frequencies is generally
fGSP <fGCK = fSSP <fSCK
It has become. In the case of so-called pseudo double speed drive, fGCK> fSSP. The image data stored in the image memory 6 as the image data storage means is data that is the basis of the data signal. The control IC 5 has a function as control means for executing a driving method of the liquid crystal display device 1 described later.

  The gate driver 3 is a scanning signal line driver, and outputs a voltage corresponding to each of the selection period and the non-selection period to each scanning signal line of the liquid crystal panel 2. Specifically, the gate driver 3 starts scanning the liquid crystal panel 2 in response to the gate start pulse signal GSP received from the control IC 5, and sequentially applies the selection voltage to each scanning signal line according to the gate clock signal GCK. .

  The source driver 4 is a data signal line driver, outputs a data signal to each data signal line of the liquid crystal panel 2, and supplies image data to each pixel on the selected scanning signal line. Specifically, based on the source start pulse signal SSP received from the control IC 5, the source driver 4 stores the received gradation data of each pixel in a register in accordance with the source clock signal SCK, and the next source latch strobe signal. Gradation data is written to each data signal line of the liquid crystal panel 2 in accordance with SLS.

  The control IC 5 is provided with a GSP conversion circuit 5A for setting the pulse interval of the gate start pulse signal GSP. The pulse interval of the gate start pulse signal GSP is about 16.7 msec when the display frame frequency is a normal 60 Hz. The GSP conversion circuit 5A can increase the pulse interval of the gate start pulse signal GSP to 167 msec, for example. Assuming that the scanning period T1 for one screen remains normal, about 9/10 of the above-described pulse interval is a period during which all scanning signal lines are in a non-scanning state. As described above, in the GSP conversion circuit 5A, the non-scanning period until the gate start pulse signal GSP is input to the gate driver 3 again after the scanning period T1 ends may be set to be longer than the scanning period T1. it can. A non-scanning period longer than the scanning period T1 is referred to as a pause period T2.

Here, FIG. 1 shows the waveforms of the scanning signals supplied to the scanning signal lines G _{1 to} G _n (n = 240) when the pause period T2 is set as the non-scanning period. If a pause period T2 longer than the scanning period T1 is set, the pause period T2 takes the place of the normal vertical blanking period (non-scanning period), and therefore the vertical period representing the frame or field becomes longer.

  When the idle period T2 is set as the non-scanning period in the GSP conversion circuit 5A, one vertical period is the sum of the scanning period T1 and the idle period T2. For example, when the scanning period T1 is set to a time equivalent to a normal 60 Hz, there is a pause period T2 longer than that, and thus the vertical frequency is lower than 30 Hz. The scanning period T1 and the non-scanning period may be appropriately set according to the degree of movement in an image to be displayed such as a still image or a moving image, and the GSP conversion circuit 5A sets a plurality of non-scanning periods according to the content of the image. Be able to. At least one of the non-scanning periods is a pause period T2. In the figure, the GSP conversion circuit 5A changes the setting of the non-scanning period in accordance with the non-scanning period setting signal M input from the outside. Although the format of the non-scanning period setting signal M may be arbitrary, for example, if it is a 2-bit logic signal, the non-scanning period can be set in four ways.

  In this manner, by providing the pause period T2, the number of times of rewriting the screen, that is, the supply frequency of the data signal output from the source driver 4 can be reduced, so that the power for charging the pixels can be reduced. Therefore, when the liquid crystal display device 1 is an active matrix type liquid crystal display device capable of ensuring basic display quality such as brightness, contrast, response speed, and gradation, the rest period T2 is set as the non-scanning period. Is set, the power consumption of the data signal line driver, which increases in direct proportion to the data signal supply frequency, can be easily and sufficiently reduced without sacrificing the display quality.

  For this reason, the non-scanning period may be set to the long pause period T2 for a display with no movement such as a still image or a display with little movement even with a moving image. For a moving image with a lot of movement, the non-scanning period may be set to a short pause period T2 or a non-scanning period shorter than the pause period T2. For example, if a non-scanning period that is sufficiently short with respect to a scanning period of 16.7 msec is set, the drive frequency is equivalent to a normal 60 Hz, so that a sufficiently fast moving image can be displayed. On the other hand, if the non-scanning period is set to a long pause period T2 of 3333 msec, it is possible to reduce the power consumption by rewriting the screen while maintaining the basic display quality for still images and moving images with little movement. it can. That is, the liquid crystal panel 2 can be used by switching between a moving image display and a low power consumption display. As described above, since the cycle of rewriting the screen can be changed in accordance with the type of display image such as a still image or a moving image, it is possible to achieve optimum low power consumption for each type of display image.

In addition, when the shortest of the plurality of non-scanning periods is T01 and any other than T01 is T02,
(T1 + T02) = (T1 + T01) × N (N is an integer of 2 or more)
In other words, the frame period using each of the plurality of non-scanning periods is preferably an integer multiple of the frame period using the shortest non-scanning period T01. For example, when driving at normal 60 Hz, T1 is 16.7 msec or less. If T01 is a vertical blanking period and T02 is set in accordance with the relationship of the above equation, the screen data signal transferred at 60 Hz may be sampled once every integer. Therefore, the reference synchronization signal can be used in common for each non-scanning period, and low frequency driving can be achieved by adding a simple circuit, and the newly generated power consumption can be made extremely small. Can do.

  Furthermore, there are logic circuits inside the gate driver 3 and the source driver 4, and each consumes power to operate the internal transistors. For this reason, the power consumption is proportional to the number of times the transistor operates, and is proportional to the clock frequency. Since all the scanning signal lines are in a non-scanning state during the pause period T2, signals other than the gate start pulse signal GSP such as the gate clock signal GCK, the source start pulse signal SSP, and the source clock signal SCK are sent to the gate driver 3 and the source driver. By not inputting to 4, it becomes unnecessary to operate the logic circuit inside the gate driver 3 and the source driver 4, so that power consumption can be reduced accordingly.

  On the other hand, when the source driver 4 is a digital driver that handles a digital data signal, an analog circuit in which a constant current flows, such as a gradation generation circuit and a buffer, exists inside the source driver 4. When the source driver 4 is an analog driver that handles analog data signals, a sampling hold circuit and a buffer exist as analog circuits. Further, there may be an analog circuit inside the control IC 5.

  Since the power consumption of the analog circuit does not depend on the driving frequency, the power consumption cannot be reduced only by stopping the operation of the logic circuit in the gate driver 3 and the source driver 4. Therefore, by stopping these analog circuits during the suspension period T2 and disconnecting the analog circuits from the power source, the power consumption of the analog circuits can be reduced, and the power consumption of the entire liquid crystal display device 1 can be further reduced. . When the liquid crystal display device 1 is an active matrix liquid crystal display device, a non-selection voltage is applied to the pixel from the gate driver 3 during the pause period T2, and therefore, an analog circuit to be stopped is associated with the gate driver 3 at a minimum. What is not to be performed, that is, what is unrelated to the display in the suspension period T2 may be used. By stopping at least the analog circuit of the source driver 4, the operation of the analog circuit with the largest power consumption is stopped, so that the power consumption of the entire liquid crystal display device 1 can be efficiently reduced.

  In addition, since no data is written to the pixels in the pause period T2, power consumption for image data transfer in the pause period T2 can be reduced by stopping the transfer of the image data from the image memory 6 in the pause period T2. it can. When stopping the transfer of image data, for example, the control IC 5 requests the image memory 6 to stop the transfer of image data based on the non-scanning period setting signal M described above. Thereby, the power consumption of the entire liquid crystal display device 1 can be further reduced while the transfer stop control is easy.

  In setting the non-scanning period, a plurality of non-scanning period setting signals may be input to the GSP conversion circuit 5A as in this example, or the non-scanning period adjustment signal may be input to the GSP conversion circuit 5A. A volume, a switch for selection, and the like may be provided. Of course, a volume for adjusting the non-scanning period, a switch for selection, and the like may be provided on the outer peripheral surface of the housing of the liquid crystal display device 1 so that the user can easily set. The GSP conversion circuit 5A may have any configuration that can change the non-scanning period to a desired setting according to at least an instruction from the outside.

  Further, as shown in FIG. 6, the control IC 5 is provided with an amplifier control circuit 5B for controlling an output amplifier connected to the data signal line. Then, the amplifier control circuit 5B sets the output amplifier in the high impedance state during the suspension period T2 and disconnects all the data signal lines from the source driver 4, thereby suppressing flickering of the screen and achieving high display quality.

  That is, the amplifier control circuit 5B can keep the potential of each data signal line constant during the pause period T2. Therefore, the data signal line such as the potential fluctuation of the pixel electrode caused by the capacitive coupling between the data signal line and the pixel electrode, which occurs when the liquid crystal display device 1 has the pixel electrode connected to the data signal line. The change in the data holding state of each pixel caused by the potential fluctuation is suppressed, and flicker is sufficiently suppressed. Therefore, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  As described above, when the operation of the analog circuit in the buffer of the source driver 4 is stopped in order to reduce power consumption, the buffer becomes the ground potential. Then, the data signal line connected to the buffer also becomes the ground potential at the same time, and when the liquid crystal display device 1 has a pixel electrode connected to the data signal line, the potential of the pixel electrode due to capacitive coupling. Variations occur. Therefore, after all the data signal lines are set to the high impedance state, the operation of the analog circuit unrelated to the display in the pause period T2 is stopped. Thereby, while reducing the power consumption of the analog circuit, it is possible to suppress a change in the data holding state of the pixel and achieve a high display quality in which flicker is further suppressed.

  Furthermore, it is more preferable that all the data signal lines are set to a high impedance state after the potential at which the change in the data holding state of all the pixels is on average is substantially minimized. For example, if the liquid crystal display device 1 has a configuration in which a liquid crystal is interposed between a pixel electrode connected to a data signal line and the counter electrode, all data signal lines are applied to an AC voltage applied to the counter electrode. The potential at the amplitude center of the AC voltage is set to the same potential as the counter electrode when a DC voltage is applied to the counter electrode. In this case, even if a pixel having a positive potential and a pixel electrode having a negative potential are mixed in AC driving, the change in the charge retention state of all the pixels due to capacitive coupling between the data signal line and the pixel electrode, that is, the data retention state The average change is almost minimal. As a result, even when the pixel data retention state differs from line to line, the change in the data retention state of the entire screen is substantially minimized, and a high display quality in which flicker is further suppressed can be achieved.

  Further, as shown in FIG. 1, when an AC voltage is applied to the transparent common electrode 19 (COM potential) during the scanning period T1, the transparent common electrode 19 is set to a potential at the amplitude center of the AC voltage during the rest period T2. . In this way, by setting the potential of the transparent common electrode 19 as described above during the rest period T2, fluctuations in the potential of the pixel electrode 27 due to capacitive coupling between each pixel and the counter electrode are suppressed. Accordingly, it is possible to achieve high display quality in which changes in the data holding state of the pixels are suppressed and flickering is suppressed.

  Here, a driving method in the case where the suspension period T2 is provided for the liquid crystal panel 2 having the above configuration will be described.

In the equivalent circuit shown in FIG. 10, by applying a selection voltage to the scanning signal line 31 and the TFT14 an ON state, and applies the data signals from the data signal line 32 to the auxiliary capacitance C _CS to the liquid crystal capacitance C _LC. Then, by the TFT14 the OFF state by applying a non-selection voltage to the scanning signal line 31, to hold the charge written in the liquid crystal capacitor C _LC and the storage capacitance C _CS. Since it is provided to avoid the position of the scanning signal line 31 auxiliary capacitance line 33 to form the auxiliary capacitance C _CS of the pixel as described above, in these equivalent circuits, for the scanning signal line 31 auxiliary capacitance Capacitive coupling with the electrode pad 27a can be ignored. Therefore, if the liquid crystal panel 2 is driven by setting the pause period T2 by the control IC 5 in this state, unlike the case where the auxiliary capacitor is formed with the Cs on-gate structure, the pixel electrode 27 of the pixel electrode 27 due to the potential fluctuation of the scanning signal line in the previous stage is formed. No potential fluctuation occurs.

  Therefore, by setting the idle period T2 and driving at a low frequency, the polarity inversion frequency of the data signal is reduced, and the power consumption of the data signal driver, in this case, the source driver 4 is sufficiently reduced. Further, by suppressing the potential fluctuation of the pixel electrode 27, it is possible to obtain a high display quality in which flickering is suppressed even when a long pause period T2 is set.

  Hereinafter, the driving method of the liquid crystal display device 1 will be described in more detail. Specifically, two driving waveforms of the pixel electrode 27 and the transparent common electrode (counter electrode) 19 in the rest period T2 will be described.

  [1] First, a driving method for fixing the potential of the data signal line 32 and / or the transparent common electrode 19 in the rest period T2 will be described with reference to FIGS.

FIG. 2 shows scanning signals (G _{1 to} G ₂₄₀ ) supplied to the scanning signal line 31 in accordance with the control of the gate driver 3 and supplied to the data signal line 32 in accordance with the control of the source driver 4 in the scanning period T 1 and the pause period T 2. Data signal (S potential), the drive waveform of the counter electrode signal (COM potential) supplied to the transparent common electrode 19 according to the control of the common driver 7, the potential of the pixel electrode 27 (D potential), and the pixel electrode 27 and the transparent common electrode 5 is a timing chart showing a potential difference (D-COM potential difference) with an electrode 19 and an optical response of the liquid crystal layer 13;

As shown in FIG. 2, in the scanning period T1, the scanning signal (G _{1 to} G ₂₄₀ ) and the data signal (S potential) corresponding to the display image are applied in an alternating waveform. Further, the case where the transparent common electrode 19 is driven with a direct current (COM potential) is shown in order to eliminate the influence of the amplitude of the potential of the transparent common electrode 19.

  Here, in the scanning period T1, the data signal line 32 is driven by the source driver 4 by 1H inversion driving in which the polarity is inverted at a sufficiently high frequency every horizontal scanning period (1H). The potential of the pixel electrode 27 (D potential) vibrates under the influence of the potential amplitude of the data signal line 32. At this time, the liquid crystal molecules of the liquid crystal layer 13 sandwiched between the transparent common electrode 19 and the pixel electrode 27 do not respond to an effective voltage V1, which is an effective value of the applied voltage in the scanning period T1, rather than a voltage oscillation in one horizontal period. To do.

  In FIG. 2, in the idle period T2, a non-selection signal is input for every scanning signal, and image data written in the scanning period T1 is held. Note that FIG. 2 shows a state where the potential of the data signal line 32 is not controlled in the pause period T2.

  In this way, by repeating the scanning period T1 and the pause period T2 in which all the data signal lines 32 are in the non-scanning state longer than the scanning period T1 for each vertical period, the supply frequency of the data signal required for one vertical period Can be reduced. Therefore, in an active matrix type liquid crystal display device, such as a matrix type display device that can ensure basic display quality such as brightness, contrast, response speed, and gradation, it is directly proportional to the data signal supply frequency. Thus, the increased power consumption of the source driver 4 can be easily and significantly reduced without sacrificing the display quality.

  Here, since the TFT 14 is in the OFF state during the idle period T2, even if the S potential as shown in FIG. 2 is applied to the data signal line 32 in theory, between the data signal line 32 and the pixel electrode 27, theoretically. No current flows, and the potential (D potential) of the pixel electrode 27 should be kept constant.

However, actually, as shown in FIG. 10, since the data signal line 32 is capacitively coupled (C _sd ) to the pixel electrode 27, the potential (D potential) of the pixel electrode 27 is the same as that of the data signal line 32. It fluctuates according to the fluctuation of the potential (S potential). As a result, the potential of the pixel electrode 27 varies every pause period T2, and flicker may occur.

  FIG. 3 is another timing chart showing each drive signal and optical response of the liquid crystal panel 2 in the scanning period T1 and the rest period T2. In FIG. 3, unlike FIG. 2, in order to reduce the amplitude of the output voltage of the source driver 4, the transparent common electrode 19 is AC driven by the drive signal (counter electrode drive signal) supplied by the common driver. In addition to the S potential, the common driver 7 performs 1H inversion driving in which the polarity of the potential of the transparent common electrode 19 is inverted every horizontal scanning period (1H period).

  Further, in the pause period T2, the potential of the data signal line 32 is changed to a potential within the voltage range of the drive signal in the scanning period T1 (data signal line pause potential) (low potential as an example in FIG. 3) under the control of the source driver 4. It is fixed with. Similarly, in the pause period T2, the common driver 19 controls the potential of the transparent common electrode 19 to be within the voltage range of the drive signal in the scanning period T1 (counter electrode pause potential) (in FIG. 3, as an example, the Low potential). It is fixed with. Specifically, by continuing to supply a predetermined potential to the source driver 4 and the common driver 7 respectively, fluctuations in the potentials of the data signal line 32 and the transparent common electrode 19 are suppressed.

Here, the potential (D potential) of the pixel electrode 27 vibrates under the influence of the respective potential amplitudes of the data signal line 32 and the transparent common electrode 19. For simplicity, a waveform is shown in which the influence of the potential fluctuation of the data signal line 32 on the potential of the pixel electrode 27 via C _sd (FIG. 10) is ignored. In actual display, the waveforms of the S potential, the D potential, and the D-COM potential difference change according to the image data included in the S potential. The liquid crystal molecules of the liquid crystal layer 13 sandwiched between the transparent common electrode 19 and the pixel electrode 27 respond to an effective voltage that is an effective value of the applied voltage in the scanning period T1, not to a voltage oscillation in one horizontal period. .

  The potential of the pixel electrode 27 at the time of non-selection is determined according to the drive waveform of the transparent common electrode 19, and theoretically, the potential difference (D-COM potential difference) between the pixel electrode 27 and the transparent common electrode 19 is all. It should be kept constant in the rest period T2.

However, in actuality, as shown in FIG. 10, the pixel electrode 27 is capacitively coupled to the scanning signal line 31 (C _gd ) and the data signal line 32 (C _sd ). Does not completely match the potential of the transparent common electrode 19.

  Here, the optical response of the pixel on the n-th line in FIG. 3 will be specifically described. First, when the pause period T2 ends (point a), scanning of the first line is started, and alternating current is applied to the transparent common electrode 19, so that the effective voltage applied to the liquid crystal layer 13 is V1, and the liquid crystal The molecule responds. When the scanning of the final line (240th line) is completed (point b), the potential of the transparent common electrode 19 is fixed at Low, so the effective voltage becomes V2, and the liquid crystal molecules respond again. Further, since the influence of the potential of the transparent common electrode 19 acts in a direction corresponding to the polarity of the potential of the pixel electrode 27 in the pause period T2, the effective voltage between the pixel electrode 27 and the transparent common electrode 19 is the point c. Effective voltage V3.

  Thus, the effective voltage applied to the liquid crystal layer 13 becomes “the difference (Vl) between the center of the potential amplitude of the pixel electrode 27 and the center of the potential amplitude of the transparent common electrode 19” in the scanning period T1. On the other hand, in the rest period T2, since the potentials of the data signal line 32 and the transparent common electrode 19 are both fixed at Low, the effective voltage applied to the liquid crystal layer 13 is “the potential of the pixel electrode 27 in the scanning period T1”. Difference between the lower limit value of the amplitude and the lower limit value of the potential amplitude of the transparent common electrode 19 (V2) ”. Moreover, the effective voltage of the rest period T2 differs in the absolute value of the effective voltage (V2 ≠ V3) between the states holding the potentials having different polarities.

  That is, when the driving is performed as shown in FIG. 3 and the potentials of the data signal line 32 and the transparent common electrode 19 in the pause period T2 are fixed at the low potential of the scanning period T1, the effective voltage applied to the liquid crystal layer 13 is changed to the scanning period. There is a difference between T1 and the rest period T2. In addition, the absolute value of the effective voltage differs between the pause periods T2 having different polarities. Therefore, every time the scanning period T1 and the rest period T2 are switched, the voltage applied to the liquid crystal layer 13 fluctuates, and the liquid crystal molecules respond each time. Therefore, although it is suppressed as compared with FIG. 2, flickering occurs. Sometimes.

  FIG. 1 is another timing chart showing each drive signal and optical response of the liquid crystal panel 2 in the scanning period T1 and the rest period T2. 1 and FIG. 3 is that the potentials of the data signal line 32 and the transparent common electrode 19 in the rest period T2 are controlled by the source driver 4 and the common driver 7, and the voltage amplitudes in the scanning period T1. Is almost equal to the center of

  Thereby, the effective voltage applied to the liquid crystal layer 13 becomes substantially equal in the scanning period T1 and the rest period T2. Therefore, flicker that occurs every scanning period T1 can be eliminated.

  Thus, in the driving method of the liquid crystal display device 1, the potentials of the data signal line 32 and the transparent common electrode 19 are stopped at the center of the potential amplitude in the scanning period T1, respectively. As a result, the influence of the potential of the data signal line 32 and the transparent common electrode 19 on the pixel electrode 27 can be made substantially equal in the scanning period T1 and the rest period T2. Therefore, even when the rest period T2 is provided, the effective value of the potential of the pixel electrode 27 can be made substantially constant and display without flicker can be realized.

  Note that the potentials of the data signal line 32 and the transparent common electrode 19 in the pause period T2 are not limited to the centers of the respective voltage amplitudes in the scanning period T1. In other words, even if the value of the data signal line 32 is changed in the range of the amplitude center ± 1.5 V and the potential of the transparent common electrode 19 is changed in the range of the amplitude center ± 1.0 V, practically flicker-free display is realized. it can.

  Here, the reason why the potential of the data signal line 32 in the pause period T2 can be set near the center of the voltage amplitude in the scanning period T1 as described above will be briefly described.

In TFT driving, the scanning signal line varies in voltage from, for example, −10 V → + 15 V → −10 V due to “scanning”, and the drain potential also varies due to the gate / drain capacitance (C _gd ). More specifically, the drain written when the scanning signal line is +15 V (gate on) changes ΔV = (− 25 V) × C _gd / (C by changing the scanning signal line to −10 V (gate off). _LC + C _CS + C _gd ). Therefore, in the TFT driving, the pull-in voltage ΔV is given as a DC offset to the counter voltage.

Of the capacitance that determines the pull-in voltage ΔV, C _CS and C _gd do not change. On the other hand, _CLC changes depending on the alignment state (gradation) of the liquid crystal. For example, in a certain positive type liquid crystal (liquid crystal that rises when a voltage is applied), the relative dielectric constant ε is about 3 at a white voltage (liquid crystal molecules are almost parallel to the substrate), and the relative dielectric constant is at a black voltage (liquid crystal molecules are almost perpendicular to the substrate). ε = about 8. In response to this change in dielectric constant, _CLC also changes.

Thus, according to the display state, i.e., because the C _LC changes every gradation, also pull the voltage ΔV varies for each gradation, because the counter electrode is a common electrode, the optimum ΔV for each pixel It is impossible to set Therefore, a voltage obtained by shifting the “amplitude center of the data signal line” in advance for each gradation is supplied to each pixel, thereby correcting the pull-in voltage ΔV that differs for each gradation.

  As described above, the center of the voltage amplitude of the data signal line 32 in the scanning period T1 differs for each gradation and depends on the display content. However, in reality, since the liquid crystal panel displays in various gradations in the entire displayable region, the average of the amplitude centers in the scanning period T1 is considered to be close to the value at the time of halftone display.

  Further, in the driving method of the liquid crystal display device 1, as shown in FIG. 1, when the suspension period T <b> 2 is entered (point d), the AC driving of the transparent common electrode 19 is stopped and controlled by the control of the common driver 7. The potential is fixed to the potential (in FIG. 1, the amplitude center of the scanning period T1), and then the source driver 4 is set to a high impedance state by the control of the amplifier control circuit 5B at a predetermined time t0 (point e). As a result, after time t0, the potential of the data signal line 32 is in a floating state. Thereafter, since the potential of the transparent common electrode 19 does not change, the potential of the data signal line 32 does not change, and the potential of the pixel electrode 27 does not change. Therefore, a display without flicker can be obtained.

  In this way, under the control of the common driver 7 and the amplifier control circuit 5B, the AC drive of the transparent common electrode 19 is first stopped in the idle period T2, and then the source driver 4 is set in the high impedance state, thereby the idle period. By reducing the steady current flowing through the amplifier in the source driver 4 at T2, power consumption can be reduced and a flicker-free display can be obtained.

  Here, in FIG. 4, as a comparative example of FIG. 1, the drive waveform and optical when the AC drive of the transparent common electrode 19 is stopped after the data signal line 32 is first set in the high impedance state in the idle period T2. The timing chart which showed the response is shown.

  That is, in FIG. 4, when the source driver 4 is set to the high impedance state at the time of entering the suspension period T2 (point f), the potential of the data signal line 32 is in a floating state. Subsequently, when the AC drive of the transparent common electrode 19 is stopped and fixed at a constant potential at a predetermined time t1 (point g), the potential of the data signal line 32 varies due to the potential of the transparent common electrode 19. The potential of the pixel electrode 27 is changed by being pulled by the potential of the data signal line 32. Therefore, when driven in this way, a flicker occurs every time the scanning period T1 and the pause period T2 are switched.

  Finally, in the liquid crystal display device 1, when the driving shown in FIG. 1 was performed, no flicker occurred and a good display was obtained. Note that the potential of the transparent common electrode 19 in the pause period T2 is 1.5 V (the amplitude of the scanning period T1 is −1 V to 4 V), and the potential of the data signal line 32 is 2 V (the amplitude of the scanning period T1 is 0 V to 4 V). .

  [2] Second, with reference to FIGS. 5 and 11 to 13, an AC voltage having a frequency lower than that in the scanning period T 1 is applied to the data signal line 32 and / or the transparent common electrode 19 in the pause period T 2. A driving method will be described.

  FIG. 5 is another timing chart showing each drive signal and optical response of the liquid crystal panel 2 in the scanning period T1 and the rest period T2.

As shown in FIG. 5, in the scanning period T1, an AC waveform corresponding to a display image is applied as a scanning signal (G _{1 to} G ₂₄₀ ) and a data signal (S potential). Further, in order to reduce the amplitude of the output voltage of the source driver 4, the transparent common electrode 19 is AC driven by the common driver 7. In addition to the S potential, the common driver 7 performs 1H inversion driving in which the polarity of the potential of the transparent common electrode 19 is inverted every horizontal scanning period (1H period).

  Further, in the pause period T2, the potential of the data signal line 32 and the transparent common electrode 19 within the voltage range of the scanning period T1 (between the maximum potential and the minimum potential) is low and low by the control of the source driver 4 and the common driver 7. Each frequency AC voltage is applied.

  Thereby, since the effective value of the voltage applied to the liquid crystal layer 13 becomes equal in the scanning period T1 and the rest period T2, the flicker that has occurred every scanning period T1 can be eliminated.

  The frequency of the AC voltage supplied to the data signal line 32 and the transparent common electrode 19 in the pause period T2 is equal to or lower than the frequency of the scanning period T1 in order to reduce power consumption. However, if the frequency is too low, the liquid crystal molecules respond to the electrode inversion and cause a new flicker. In addition, the frequency of the drive signal applied to the data signal line 32 and the transparent common electrode 19 in the idle period T2 is generally 30 Hz or higher, more preferably about 45 Hz or higher, so that a flicker-free display can be obtained. Has been confirmed.

  Finally, when the driving shown in FIG. 5 was performed in the liquid crystal display device 1, no flickering occurred and a good display was obtained. It should be noted that the potential of the transparent common electrode 19 in the rest period T2 is the same as the amplitude −1V to 4V in the scanning period T1, the frequency is 60 Hz, and the potential of the data signal line 32 is the same as the amplitude 0V to 4V in the scanning period T1. The potential was 60 Hz and the frequency.

  Here, the amplitude of the AC voltage supplied to the data signal line 32 and the transparent common electrode 19 in the pause period T2 is desirably set to a potential within the voltage range of the scanning period T1, as shown in FIG. However, the amplitude of the AC voltage supplied to the data signal line 32 in the pause period T2 can be set to a potential exceeding the maximum amplitude in the scanning period T1, as shown in FIG.

  Hereinafter, the configuration of the liquid crystal display device 1 that applies an AC signal exceeding the maximum amplitude of the scanning period T1 to the data signal line 32 in the pause period T2 will be described with reference to FIGS.

  First, the liquid crystal display device 1 shown in FIG. 12 is provided with an AC voltage generation circuit 8 and switches 9 in addition to the configuration shown in FIG.

  The AC voltage generation circuit 8 is a circuit that generates an AC voltage to be supplied to the data signal line 32 in the idle period T2. The frequency of the generated AC voltage is equal to or lower than the frequency of the scanning period T1, as in FIG. The amplitude of the AC voltage is a drive signal for the transparent common electrode 19 in the pause period T2 so that the effective value of the potential of the pixel electrode 27 due to the D-COM potential difference is substantially constant during the scan period T1 and the pause period T2. Is set according to

  The switch 9 is provided for each data signal line 32 between the source driver 4 and the liquid crystal panel 2. The switch 9 applies a drive signal from the source driver 4 to the data signal line 32 during the scanning period T1 and a drive signal from the AC voltage generation circuit 8 during the idle period T2 according to the amplifier control signal from the amplifier control circuit 5B. It is switched to supply.

  As a result, it is possible to supply the drive signal in the pause period T2 of the data signal line 32 from the AC voltage generation circuit 8 and to pause the source driver 4 in the pause period T2. Therefore, power consumption required for the source driver 4 during the suspension period T2 can be reduced.

  Further, by setting the output voltage amplitude of the AC signal generation circuit 8 to the reference power supply voltage, that is, the existing amplitude of 0V-3V or 0V-5V, it is not necessary to generate a new intermediate potential (for example, 4V). . Therefore, since there is no boost loss that occurs when the intermediate potential is created, it is possible to suppress the power loss and realize further reduction in power consumption.

  Further, as shown in FIG. 11, after the scanning of one screen is completed and the suspension period T2 is entered, the same drive signal as that in the scanning period T1 is input to the data signal line 32 for a certain period (continuation period). Also good. Here, in FIG. 11, there is a continuation period in which the input of the same drive signal as the scanning period T1 is continued at the beginning of the pause period T2 until the signals input to the data signal line 32 and the transparent common electrode 19 are the same. There are two types (between h-i: t2 = 4H, j-k: t3 = 3H). That is, in the driving method according to the timing chart of FIG. 11, the two durations are changed for each frame. Here, the two durations are both sufficiently smaller than the pause period T2, and the difference (| t2-t3 |) is an odd multiple of one horizontal scanning period (n × H (n = 1, 3, 3). 5, ...)), it can be set arbitrarily.

  As described above, the liquid crystal display device 1 supplies the timing for switching the drive signal for driving the data signal line 32 and the transparent common electrode 19 to the same voltage while shifting by an odd multiple of one horizontal period. As a result, it was confirmed that a stable display without flicker could be obtained. In FIG. 11, when the drive signal for driving the data signal line 32 and the transparent common electrode 19 is switched to the same voltage, the frequency is switched to a low frequency at the same time, but the timing for switching the frequency is the same as the voltage switching. It may be sufficient and may be shifted back and forth.

  When the liquid crystal display device 1 was driven as shown in FIG. 11, a flicker-free display was obtained. In the rest period T2, the data signal line 32 is disconnected from the source driver, connected to the AC voltage generation circuit 8, and an AC signal having a frequency of 30 Hz or more, preferably 45 Hz or more is applied. In the present embodiment, the frequency is set to 60 Hz by using a clock signal having one vertical cycle during scanning, and the amplitude is set to 0 V and 5 V whose potentials are reference power supply voltages.

  Further, as shown in FIG. 13, the AC signal generation circuit 8 may be shared by a common driver 7. That is, in the idle period T2, the drive signal from the common driver 7 may be supplied to the data signal line 32 together with the transparent common electrode 19 (counter electrode). Note that the amplitude of the drive signal in the pause period T2 may be the same as the amplitude of the drive signal applied to the transparent common electrode 19 in the scanning period T1, or less than the maximum amplitude (that is, within the voltage range of the drive signal). It may be. Of course, it is also possible to supply the drive signal from the AC signal generation circuit 8 to the data signal line 32 and the transparent common electrode 19 in the pause period T2 to pause the source driver 4 and the common driver 7 (not shown). )

Thus, a common drive signal can be applied from the common driver 7 to the transparent common electrode 19 (counter electrode) and the data signal line 32 during the idle period T2. Therefore, since it is not necessary to newly provide the AC signal generation circuit 8 for driving the data signal line 32 during the suspension period T2, it is possible to prevent the circuit of the liquid crystal display device 1 from becoming large and complicated. Further, since a common drive signal is input to the data signal 32 and the transparent common electrode 19, charging / discharging to the capacity (C _{cd in} FIG. 10) between the transparent common electrode 19 and the data signal line 32 is eliminated. It becomes possible to reduce power consumption.

  Here, in FIG. 11, when the drive signal applied to the data signal line 32 in the pause period T2 is the same as the drive signal applied to the transparent common electrode 19, the potential of the data signal line 32 is changed between the scanning period T1 and the pause period T2. Strictly speaking, there is a slight shift in the effective value of the D-COM potential difference.

However, in general, since C _sd / (C _gd + C _sd + C _LC + C _CS ) in FIG. 10 is about 1/20, the above-described effective value fluctuation is practically a level that causes no problem. Therefore, even if the potentials of the data signal line 32 and the transparent common electrode 19 in the pause period T2 are changed in the range of the amplitude center ± 1.0 V in the scanning period T1, a display with no flicker can be realized practically.

  In order to further reduce flicker, it is effective to increase the frequency of the drive signal applied during the pause period T2. In the above driving method, since a common potential is input to the source and the common, no charge is charged / discharged between the source / common, but a charge / discharge is generated between the gate / source and between the gate / common. When the frequency is increased, the power consumption reduction effect is reduced.

  Then, when the detailed examination was performed about the relationship between the drive frequency in the idle period T2 and the perception limit of flickering, the results shown in Table 1 were obtained. Therefore, in the present embodiment, the driving frequency applied to the data signal line 32 and the transparent common electrode 19 in the pause period T2 is set to 500 Hz, which is the lowest frequency at which flicker cannot be perceived completely.

Since the parameters (C _LC , C _{CS, etc.} ) of the liquid crystal panel 2 are different for each type of the liquid crystal panel 2, the optimum driving frequency is different for each type of liquid crystal panel. The drive frequency is preferably large for display quality, but small for power saving. Therefore, the driving frequency in the pause period T2 is optimized based on the parameters, usage, and the like of the liquid crystal panel 2. For example, the driving signal in the pause period T2 may be a driving signal having a driving frequency of 0, that is, a DC signal.

  As described above, according to the liquid crystal display device 1, in the configuration having active elements, the rest period T2 longer than the scan period T1 is provided after the scan period T1 for rewriting one screen, and the data signal lines 32 and By optimally controlling the potential of the transparent common electrode 19, low power consumption can be achieved while maintaining display quality without flickering.

  The driving method of the liquid crystal display device 1 is such that when image data having a general gradation distribution is input in the scanning period T1, the potentials of the data signal line 32 and the transparent common electrode 19 in the pause period T2 are set respectively. This is realized by setting the center of the scanning period T1. However, the combination of the potentials of the data signal line 32 and the transparent common electrode 19 may be obtained from the potential of the scanning period T1 immediately before or before. Furthermore, when the polarity is reversed, it may be set every other rest period T2.

  The present embodiment does not limit the scope of the present invention, and various modifications are possible within the scope of the present invention, and can be configured as follows.

  For example, in the driving method of the display device according to this embodiment, a plurality of active elements are provided on one of a pair of substrates arranged to face each other, and a desired voltage is applied between the substrates through the active elements. In the method for driving a display device for controlling the transmittance or reflectance of light, a pause period in which all scanning signal lines longer than the scan period are non-scanned is provided after the scan period for scanning one screen, and the pause period Alternatively, the potential of the counter electrode may be fixed (not AC driven).

  In the display device driving method, the potential of the counter electrode in the pause period may be selected from the amplitude of the counter signal voltage supplied in the scanning period.

  Further, in the above driving method of the display device, the potential of the counter electrode during the pause period is in the vicinity of the amplitude center of the counter signal voltage supplied during the scanning period (in the case of a liquid crystal display device, the amplitude center is within ± 1 V). It may be set. Thereby, a favorable display device with low power consumption can be realized.

  The display device driving method includes providing a plurality of active elements on one of a pair of substrates arranged opposite to each other, applying a desired voltage between the substrates through the active elements, and transmitting light. In the driving method of the display device for controlling the rate or the reflectance, after the scanning period for scanning one screen, there is provided a resting period in which all scanning signal lines are in a non-scanning state for a period longer than the scanning period. The potential of the data signal wiring may be fixed (not AC driven).

  Further, in the driving method of the display device, the potential of the data signal wiring in the idle period may be selected from the amplitude of the data signal voltage supplied in the scanning period.

  Further, in the above driving method of the display device, the potential of the data signal wiring in the pause period is in the vicinity of the amplitude center of the data signal wiring voltage supplied in the scanning period (in the case of a liquid crystal display device, the amplitude center ± 1. 5V or less). Thereby, a favorable display device with low power consumption can be realized.

  In the driving method of the display device, the output amplifier of the data signal driver may be in a high impedance state after the AC driving of the counter electrode signal and the data signal wiring is stopped during the pause period.

  In addition, in the driving method of the display device according to this embodiment, a plurality of active elements are provided on one of a pair of substrates arranged to face each other, and a desired voltage is applied between the substrates through the active elements. In the method for driving a display device for controlling the light transmittance or reflectance, a pause period is provided after the scanning period for scanning one screen for a period longer than the scanning period in which all scanning signal lines are in a non-scanning state. The voltage is substantially equal to the driving signal supplied to the counter electrode in the period during the scanning period and the frequency is smaller than the driving signal (in the case of a liquid crystal display device, the frequency is ½ or less of the driving signal, In addition, an alternating current of 45 Hz or more may be applied. Thereby, a favorable display device with low power consumption can be realized.

  The display device driving method includes providing a plurality of active elements on one of a pair of substrates arranged opposite to each other, applying a desired voltage between the substrates through the active elements, and transmitting light. In the method of driving a display device for controlling the rate or the reflectance, after the scanning period for scanning one screen, there is provided a pause period in which all scanning signal lines are in a non-scanning state for a period longer than the scan period, and the data signal of the pause period The voltage is an arbitrary halftone potential with respect to the drive signal supplied to the line during the scanning period, and the frequency is smaller than that of the drive signal. The alternating current of 45 Hz or more may be applied. As a result, a display device with low power consumption and good display performance without flickering can be realized.

  In the driving method of the display device described above, the AC voltage supplied to the counter electrode and the data signal wiring may be vibrated synchronously during the pause period. Thereby, flicker can be reduced more effectively.

  Further, in the driving method of the display device according to this embodiment, each line of the screen in which pixels are arranged in a matrix is selected and scanned by a plurality of scanning signal lines, and the pixels of the selected line are scanned. In a driving method of a display device that performs display by supplying a data signal from a data signal line, a rest period in which all the scanning signal lines are in a non-scanning state is longer than the scanning period, following a scanning period for scanning one screen. In the idle period, the data signal line is disconnected from the data signal driver by a switch, and the data signal line is connected to an AC signal generating circuit, and has an arbitrary amplitude (for example, the same as the AC signal generating circuit). (Amplitude), and an AC drive signal having a frequency equal to or lower than the frequency of the data signal may be applied. Note that the amplitude of the drive signal supplied to the data signal line in the pause period is not limited to the voltage range in the scanning period. By the above method, the data signal driver can be paused by disconnecting the data signal line from the data signal driver by the switch and connecting it to the AC signal generating circuit during the pause period. In addition, the drive signal for the data signal line in the idle period may be supplied from an AC voltage generation circuit (common driver) that supplies the drive signal to the counter electrode.

  Note that in the driving method of the display device of the present invention, each scanning signal line on the screen in which pixels are arranged in a matrix is selected and scanned, and a data signal is supplied from the data signal line to the pixels on the selected line. In the driving method of a display device that performs display, a pause period in which all the scanning signal lines are in a non-scanning state is provided longer than the scan period, followed by a scan period in which one screen is scanned. The potential of the data signal line may be fixed to a predetermined data signal line pause potential.

  In the driving method of the display device of the present invention, the data signal line pause potential of the data signal line in the pause period may be set within the voltage range of the data signal supplied to the data signal line in the scan period. .

  In the driving method of the display device of the present invention, the data signal line pause potential of the data signal line in the pause period may be set at the amplitude center of the data signal supplied to the data signal line in the scan period.

  According to the above method, the data signal line driver (source driver) that increases in direct proportion to the supply frequency of the data signal is provided by providing a rest period longer than the scanning period as the non-scanning period after the scanning period for rewriting one screen. Power consumption can be easily reduced.

  Further, by fixing the potential of the data signal line in the pause period to the data signal line pause potential, the potential of the data signal line in the pause period can be optimally controlled. That is, the influence of the potential of the data signal line on the pixel electrode can be made substantially equal in the scanning period and the pause period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The data signal line pause potential that fixes the potential of the data signal line in the pause period is preferably set within the voltage range of the data signal supplied to the data signal line in the scan period. Further, the data signal line rest potential is more preferably set at the amplitude center of the data signal supplied to the data signal line during the scanning period.

  In the case of an active matrix liquid crystal display device, practically flicker-free display can be realized even when the potential of the data signal line in the pause period is changed within the range of the amplitude center ± 1.5 V in the scanning period.

  The display device driving method of the present invention selects and scans each scanning signal line on a screen in which pixels are arranged in a matrix, and supplies a data signal from the data signal line to the pixels on the selected line. In the driving method of a display device that performs display, a pause period in which all the scanning signal lines are in a non-scanning state is provided longer than the scan period, followed by a scan period in which one screen is scanned. The potential of the counter electrode may be fixed to a predetermined counter electrode rest potential.

  In order to solve the above problems, the display device driving method of the present invention further uses the counter electrode rest potential of the counter electrode in the rest period as the voltage of the counter electrode drive signal supplied to the counter electrode in the scan period. It is characterized by setting within the range.

  In the driving method of the display device of the present invention, the counter electrode pause potential of the counter electrode in the pause period may be set to the amplitude center of the counter electrode drive signal supplied to the counter electrode in the scan period.

  Even when the counter electrode is AC driven to reduce the amplitude of the output voltage of the data signal driver by the above method, a non-scanning period longer than the scanning period after the scanning period for rewriting one screen Thus, the power consumption of the counter electrode driver (common driver) that increases in direct proportion to the supply frequency of the data signal can be easily reduced.

  In addition, by fixing the potential of the counter electrode in the rest period to the counter electrode rest potential, the potential of the counter electrode in the rest period can be optimally controlled. That is, the influence of the potential of the counter electrode on the pixel electrode can be made almost equal in the scanning period and the rest period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The counter electrode pause potential that fixes the potential of the counter electrode during the pause period is preferably set within the voltage range of the counter electrode drive signal supplied to the counter electrode during the scanning period. Furthermore, the counter electrode rest potential is more preferably set at the amplitude center of the counter electrode drive signal supplied to the counter electrode during the scanning period.

  Note that, in the case of an active matrix liquid crystal display device, a practically flicker-free display can be realized even if the potential of the counter electrode in the pause period is changed within the range of the amplitude center ± 1.0 V in the scanning period.

  Further, the display device driving method of the present invention is based on the above-described display device driving method, and the potential of the data signal line is fixed to the data signal line rest potential in the idle period, and the above display device driving method is used. During the pause period, the counter electrode potential may be fixed at the counter electrode pause potential.

  By the above method, a non-scanning period longer than the scanning period is provided after the scanning period for rewriting one screen, so that the frequency increases in direct proportion to the frequency of the drive signal supplied to the data signal line and the counter electrode. Power consumption can be easily reduced.

  Further, by fixing the potentials of the data signal line and the counter electrode in the pause period to the data signal line pause potential and the counter electrode pause potential, respectively, the potentials of the data signal line and the counter electrode in the pause period can be optimally controlled. It becomes possible. That is, the influence of the potential of the data signal line and the counter electrode on the pixel electrode can be made almost equal in the scanning period and the rest period. Here, the data signal line rest potential and the counter electrode rest potential may be set so that the effective voltage between the pixel electrode and the counter electrode is substantially equal between the scanning period and the rest period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  In the display device driving method of the present invention, the potential of the data signal line and the potential of the counter electrode are fixed to the data signal line pause potential and the counter electrode pause potential, respectively, in the pause period. The data signal line may be in a high impedance state with respect to the data signal driver that supplies the data signal to the data signal line.

  By the above method, all the data signal lines are further disconnected from the data signal driver during the idle period so that the data signal driver is in a high impedance state, so that the potential of each data signal line is kept constant during the idle period. can do.

  Accordingly, each variation caused by the potential variation of the data signal line such as the potential variation of the pixel electrode caused by capacitive coupling between the data signal line and the pixel electrode, which occurs in the display device having the pixel electrode connected to the data signal line. The change in the data holding state of the pixel is suppressed, and the flickering of the screen is sufficiently suppressed.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The display device driving method of the present invention selects and scans each scanning signal line on a screen in which pixels are arranged in a matrix, and supplies a data signal from the data signal line to the pixels on the selected line. In the driving method of a display device that performs display, a pause period in which all the scanning signal lines are in a non-scanning state is provided longer than the scan period, followed by a scan period in which one screen is scanned. An AC drive signal having a frequency equal to or lower than the frequency of the data signal supplied to the data signal line during the scanning period may be applied to the data signal line.

  In the display device driving method of the present invention, the amplitude of the driving signal applied to the data signal line during the pause period is further set within the voltage range of the data signal supplied to the data signal line during the scanning period. Also good.

  By the above method, after a scanning period in which one screen is rewritten, a non-scanning period longer than the scanning period is provided, and the frequency of the drive signal supplied to the data signal line is made smaller than the scanning period, whereby the data signal The power consumption of the data signal line driver (source driver) that increases in direct proportion to the supply frequency can be easily reduced.

  The upper limit of the frequency of the drive signal supplied to the data signal line in the pause period is preferably smaller than the drive signal in the scanning period, preferably 1/2 or less of the frequency of the drive signal, and 1/10 or less. More preferably. In addition, the lower limit of the frequency of the drive signal supplied to the data signal line during the pause period may be 30 Hz or more, more preferably 45 Hz. According to this setting, a flicker-free display can be obtained.

  In addition, the drive signal supplied to the data signal line in the pause period is set in the pause state by setting the amplitude within the voltage range of the data signal supplied to the data signal line in the scanning period and the frequency equal to or lower than the frequency of the data signal. It is possible to optimally control the potential of the data signal line in the period. That is, the influence of the potential of the data signal line on the pixel electrode can be made substantially equal in the scanning period and the pause period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The display device driving method of the present invention selects and scans each scanning signal line on a screen in which pixels are arranged in a matrix, and supplies a data signal from the data signal line to the pixels on the selected line. In the driving method of a display device that performs display, a pause period in which all the scanning signal lines are in a non-scanning state is provided longer than the scan period, followed by a scan period in which one screen is scanned. An AC drive signal having a frequency within the voltage range of the counter electrode drive signal supplied to the counter electrode during the scanning period and having a frequency equal to or lower than the frequency of the counter electrode drive signal may be applied to the counter electrode.

  Even when the counter electrode is AC driven to reduce the amplitude of the output voltage of the data signal driver by the above method, a non-scanning period longer than the scanning period after the scanning period for rewriting one screen By reducing the frequency of the drive signal supplied to the counter electrode shorter than the scanning period, the power consumption of the counter electrode driver (common driver) that increases in direct proportion to the supply frequency of the counter electrode drive signal can be easily achieved. Can be reduced.

  In addition, by setting the drive signal supplied to the counter electrode in the pause period within the voltage range of the counter electrode drive signal supplied to the counter electrode in the scanning period, the frequency is equal to or lower than the frequency of the counter electrode drive signal. In addition, it is possible to optimally control the potential of the counter electrode during the rest period. That is, the influence of the potential of the counter electrode on the pixel electrode can be made almost equal in the scanning period and the rest period. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The upper limit of the frequency of the drive signal supplied to the counter electrode during the pause period is preferably smaller than the drive signal during the scanning period, preferably 1/2 or less of the frequency of the drive signal, and 1/10 or less. More preferable. In addition, the lower limit of the frequency of the drive signal supplied to the counter electrode during the pause period may be 30 Hz or more, more preferably 45 Hz. According to this setting, a flicker-free display can be obtained.

  Further, the display device driving method of the present invention applies the AC drive signal to the data signal line during the pause period by the display device drive method, and the display device drive method. During the period, an AC drive signal may be applied to the counter electrode, and the frequency and phase of both of the drive signals may match.

  By the above method, a non-scanning period longer than the scanning period is provided after the scanning period for rewriting one screen, so that the frequency increases in direct proportion to the frequency of the drive signal supplied to the data signal line and the counter electrode. Power consumption can be easily reduced.

  In addition, the data signal line and the counter electrode are driven in the idle period by the drive signal whose amplitude is equal to or less than the frequency of the drive signal in the voltage range of the drive signal supplied in the scanning period. It is possible to optimally control the potentials of the data signal line and the counter electrode. That is, the influence of the potential of the data signal line and the counter electrode on the pixel electrode can be made almost equal in the scanning period and the rest period. Here, the amplitude and frequency of each drive signal supplied to the data signal line and the counter electrode in the pause period are such that the effective voltage between the pixel electrode and the counter electrode is substantially the same in the scan period and the pause period. You can set it. Note that it is desirable that the phases of the drive signals supplied to the data signal line and the counter electrode in the rest period coincide. Therefore, even when the rest period is provided, the effective value of the potential of the pixel electrode can be made substantially constant and display without flicker can be realized.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  The driving method of the display device of the present invention may fix the potential of the data signal line to the data signal line pause potential and the potential of the counter electrode to the counter electrode pause potential in the pause period. An AC drive signal may be applied to the data signal line and an AC drive signal may be applied to the counter electrode. Further, the driving method of the display device of the present invention may fix the potential of the data signal line to the data signal line resting potential and apply an AC driving signal to the counter electrode in the resting period. An alternating drive signal may be applied to the data signal line, and the counter electrode potential may be fixed to the counter electrode rest potential.

  The display device driving method of the present invention selects and scans each scanning signal line on a screen in which pixels are arranged in a matrix, and supplies a data signal from the data signal line to the pixels on the selected line. In the driving method of a display device that performs display, a pause period in which all the scanning signal lines are in a non-scanning state is provided longer than the scan period, followed by a scan period in which one screen is scanned. The AC drive signal is applied to the counter electrode while the amplitude is within the voltage range of the counter electrode drive signal supplied to the counter electrode during the scanning period, and the frequency is equal to or less than the frequency of the counter electrode drive signal. A signal may also be applied to the data signal line.

  The display device driving method of the present invention selects and scans each scanning signal line on a screen in which pixels are arranged in a matrix, and supplies a data signal from the data signal line to the pixels on the selected line. In the driving method of a display device that performs display, a pause period in which all the scanning signal lines are in a non-scanning state is provided longer than the scan period, followed by a scan period in which one screen is scanned. In addition, a direct current drive signal having a potential within the voltage range of the common electrode drive signal supplied to the common electrode during the scanning period is applied to the common electrode, and the direct current drive signal is also applied to the data signal line. Also good.

  By the above method, a non-scanning period longer than the scanning period is provided after the scanning period for rewriting one screen, so that the frequency increases in direct proportion to the frequency of the drive signal supplied to the data signal line and the counter electrode. Power consumption can be easily reduced.

  In addition, the data signal line and the counter electrode in the pause period may be an AC drive signal whose amplitude is within the voltage range of the counter electrode drive signal supplied to the counter electrode in the scanning period and the frequency is equal to or less than the frequency of the counter electrode drive signal, or By driving with a DC drive signal having a potential within the voltage range of the counter electrode drive signal, the potential difference between the data signal line and the counter electrode in the idle period can be optimally controlled. That is, the influence of the potential of the data signal line and the counter electrode on the pixel electrode can be made substantially equal in the scanning period and the rest period.

  Therefore, since the amplitude and phase of the drive signal supplied to the data signal line and the counter electrode coincide in the pause period, even if the pause period is provided, the effective value of the potential of the pixel electrode is made substantially constant, and display without flicker is achieved. realizable.

  In addition, since the drive signal of the data signal line can be supplied from the AC signal generation circuit (common driver) that supplies the drive signal to the counter electrode in the idle period, the data signal driver is disconnected from the data signal line during the idle period. The power consumption can be reduced by separating and suspending the data signal driver.

  Therefore, in a matrix display device, it is possible to achieve both a sufficiently low power consumption and a high display quality in which flicker is sufficiently suppressed.

  In the case of an active matrix liquid crystal display device, a practically flicker-free display can be realized even when the potentials of the data signal line and the counter electrode in the pause period are changed within a range of the amplitude center of ± 1.0 V in the scanning period. .

  The display device of the present invention may include control means for executing the above driving method.

  With the above structure, it is possible to achieve both low power consumption and high display quality in which flicker is sufficiently suppressed in a matrix display device. For example, according to a liquid crystal display device, low power consumption can be achieved while maintaining good display quality in a configuration having active elements.

4 is a timing chart illustrating each driving signal and optical response of the liquid crystal panel during a scanning period and a rest period, for explaining a driving method of the display device according to the embodiment of the present invention. 4 is a timing chart illustrating each driving signal and optical response of the liquid crystal panel during a scanning period and a rest period, for explaining a driving method of the display device according to the embodiment of the present invention. 4 is a timing chart illustrating each driving signal and optical response of the liquid crystal panel during a scanning period and a rest period, for explaining a driving method of the display device according to the embodiment of the present invention. 3 is a timing chart for explaining a comparative example of a method for driving the display device illustrated in FIG. 1. 4 is a timing chart illustrating each driving signal and optical response of the liquid crystal panel during a scanning period and a rest period, for explaining a driving method of the display device according to the embodiment of the present invention. It is a block diagram which shows the outline of a structure of the liquid crystal display device using the drive method of the display device shown in FIG.1, FIG.5, FIG.11. It is a block diagram which shows the outline of a structure of the liquid crystal panel which the liquid crystal display device shown in FIG. 6 comprises. It is sectional drawing which shows the outline of a structure of the liquid crystal panel which the liquid crystal display device shown in FIG. 6 comprises. FIG. 7 is a perspective plan view illustrating an outline of a configuration of a liquid crystal panel included in the liquid crystal display device illustrated in FIG. 6. FIG. 7 is a circuit diagram showing an equivalent circuit of the liquid crystal panel shown in FIG. 6. 4 is a timing chart illustrating each driving signal and optical response of the liquid crystal panel during a scanning period and a rest period, for explaining a driving method of the display device according to the embodiment of the present invention. It is a block diagram which shows the outline of the other structure of the liquid crystal panel which the liquid crystal display device shown in FIG. 6 comprises. FIG. 7 is a block diagram illustrating an outline of still another configuration of the liquid crystal panel included in the liquid crystal display device illustrated in FIG. 6.

Explanation of symbols

1 Liquid crystal display device (display device)
2 LCD panel (screen)
4 Source driver (data signal driver)
5 Control IC (control means)
19 Transparent common electrode (counter electrode)
31 Scanning signal line 32 Data signal line T1 Scanning period T2 Rest period

Claims (11)

In a driving method of a display device that performs scanning by selecting and scanning each scanning signal line of a screen in which pixels are arranged in a matrix, and supplying a data signal from the data signal line to the pixels of the selected line,
Following the scanning period for scanning one screen, a pause period is provided in which all scanning signal lines are in a non-scanning state longer than the scanning period,
And in the case of fixing the potential of the data signal line to a predetermined data signal line resting potential in the resting period,
A display device driving method, wherein the predetermined data signal line rest potential is set at the amplitude center of a data signal supplied to the data signal line during the scanning period.   The display device driving method according to claim 1, wherein the potential of the counter electrode is fixed to a predetermined counter electrode rest potential during the rest period.   2. The display device driving method according to claim 1, wherein a counter electrode pause potential of the counter electrode in the pause period is set within a voltage range of a counter electrode drive signal supplied to the counter electrode in the scanning period. . In a driving method of a display device that performs scanning by selecting and scanning each scanning signal line of a screen in which pixels are arranged in a matrix, and supplying a data signal from the data signal line to the pixels of the selected line,
Following the scanning period for scanning one screen, a pause period is provided in which all scanning signal lines are in a non-scanning state longer than the scanning period,
And, in the case of fixing the potential of the counter electrode to a predetermined counter electrode pause potential in the pause period,
A display device driving method, wherein the predetermined counter electrode rest potential is set at an amplitude center of a counter electrode drive signal supplied to the counter electrode during the scanning period.   5. The method of driving a display device according to claim 4, wherein the potential of the data signal line is fixed to a predetermined data signal line pause potential during the pause period.   5. The display device drive according to claim 4, wherein a data signal line pause potential of the data signal line in the pause period is set within a voltage range of a data signal supplied to the data signal line in the scanning period. Method.   In the pause period, a DC drive signal having the predetermined counter electrode pause potential set at the amplitude center of the counter electrode drive signal supplied to the counter electrode in the scanning period is applied to the counter electrode, and the DC 5. The method of driving a display device according to claim 4, wherein the driving signal is also applied to the data signal line.   A display device comprising control means for executing the method for driving the display device according to claim 1.   A portable device comprising the display device according to claim 8. According to the driving method of the display device according to claim 1, the potential of the data signal line is fixed to the data signal line pause potential during the pause period,
5. The display device driving method according to claim 4, wherein the potential of the counter electrode is fixed to the counter electrode rest potential during the rest period. In the above suspension period,
After fixing the potential of the data signal line and the potential of the counter electrode to the data signal line rest potential and the counter electrode rest potential, respectively,
11. The method of driving a display device according to claim 10, wherein the data signal line is set to a high impedance state with respect to a data signal driver that supplies a data signal to the data signal line.

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