JP2002341836A - Liquid crystal display device, image display application device, and portable information terminal device - Google Patents

Abstract

(57) [Problem] To reduce power consumption when displaying a binary video signal on a liquid crystal display device. SOLUTION: In an active matrix type liquid crystal display device in which pixels are arranged in a row direction and a column direction, when displaying a multi-tone image and a binary image, input multi-tone data and a pixel row of a liquid crystal panel are displayed. Display frame period TV1 from number
Is determined, the power consumption is reduced by enlarging the display frame cycle TV2 on the liquid crystal panel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device for reducing the power consumption of a liquid crystal panel by changing the frame frequency of a liquid crystal display in accordance with the amount of information of a video signal and the number of display lines. The present invention relates to a mounted image display application device and a portable information terminal device.

[0002]

2. Description of the Related Art In recent years, an active matrix type liquid crystal display device has been proposed as a display device for a portable terminal for displaying a color moving image or the like, from the viewpoints of improving image quality and shortening response speed by increasing viewing angle and definition. Is used.

FIG. 8 is a configuration diagram of a conventional active matrix type liquid crystal display device. The configuration and operation of the conventional liquid crystal display device will be described with reference to FIG. The liquid crystal panel 1 is an active matrix type liquid crystal panel, and includes a pixel electrode 10, a scanning signal line 11, and a data signal line 1.
2, a switching element 13 and a counter electrode 14.

The pixel electrode 10 is an electrode arranged in a matrix in the row direction and the column direction, and is in contact with each liquid crystal cell. The scanning signal lines 11 are row direction signal lines for selecting pixels in the same row direction, and it is assumed that p scanning signal lines 11 are provided along the column direction of the liquid crystal panel 1. The data signal lines 12 are column direction signal lines for transmitting an applied voltage corresponding to display data to pixels in the same column direction, and it is assumed that q data signal lines 12 are provided along the row direction of the liquid crystal panel. The switching element 13 is a switching element that transmits data of a data signal line to a pixel of a liquid crystal cell by a scanning signal. Switching element 13
Has a control output terminal connected to the pixel electrode 10, a first control input terminal to which a scanning signal is input, and a second control input terminal to which a pixel signal for row scanning is applied.
It is composed of T. The counter electrode 14 is an electrode for supplying a common voltage of each liquid crystal cell. A liquid crystal cell is held between the pixel electrode 10 and the counter electrode 14. One set of pixel electrodes 10
The liquid crystal cell sandwiched between the liquid crystal cell and the counter electrode 14 is called a pixel.

[0005] The liquid crystal cell functions as a shutter for adjusting the amount of light transmitted by the voltage applied between the pixel electrode 10 and the counter electrode 14. In the case of a normally white liquid crystal panel, the relationship between the applied voltage between the pixel electrode 10 and the counter electrode 14 and the luminance is as shown in FIG. R for each pixel
If RGB color filters are provided on the counter electrode 14 side for RGB, RGB light is synthesized by the human eye to recognize a color image. RGB pixel signals are assigned to the data signal lines 12 based on the RGB arrangement of the pixels.

The gate driver 2 is a row direction drive circuit for applying a scanning signal to the scanning signal line 11 in the liquid crystal panel 1. The source driver 3 is a column-direction drive circuit that generates a voltage applied to the data signal line 12 in the liquid crystal panel 1 according to display data and outputs this voltage as a pixel signal.

[0007] The video signal processing circuit 4 is a circuit for inputting a video signal from the outside and outputting display data to the source driver 3. The control signal generation circuit 5 is a circuit that outputs a control signal to the gate driver 2, the source driver 3, and the video signal processing circuit 4.

Next, the operation of displaying an image on the liquid crystal panel 1 will be described. When the control signal generation circuit 5 controls the gate driver 2 by the gate drive control signal, the gate driver 2 applies a scanning signal to the scanning signal line 11 on an arbitrary row of the liquid crystal panel 1. The switching element 13 connected to the scanning signal line 11 is turned on, and in the selected scanning signal line 11, the data line 12 and the pixel electrode 1 of each column are connected.
0 is conducted.

On the other hand, the video signal processing circuit 4 supplies display data corresponding to each pixel of the row to which the scanning signal is supplied to the source driver 3 in advance. And source driver 3
While the switching element 13 is in the on state,
The display data is converted into a voltage applied to each pixel electrode 10 and output. The control signal generating circuit 5 outputs a control signal for sequential scanning from the uppermost row (i = 1) to the lowermost row (i = p) of the liquid crystal panel 1, for example, so that the liquid crystal panel 1
Display information on the full screen of.

In such a liquid crystal display device, the image display frame frequency on the liquid crystal panel 1 is set to a frequency at which flickering of the screen is not perceived by human eyes. Therefore, a frequency of about 60 Hz or more is used. The scanning frequency at which the control signal generating circuit 5 controls the gate driver 2 and the source driver 3 to perform sequential scanning is determined by the number p of scanning signal lines of the liquid crystal display panel 1 and the video display frame frequency ftv on the liquid crystal panel 1. The source driver 3 and the switching element 13 sufficiently charge the pixel electrode 10 during one scanning period TH (the reciprocal of the scanning frequency). The pixel electrode 10 holds the signal charge written in one scanning period TH for one frame period TV (reciprocal of the frame frequency ftv) until updating to the next display data.

FIG. 10 is a drive timing chart of a conventional liquid crystal display device. Xi (i = 1, 2, 3,...,
p) indicates an output signal of the gate driver 2. Yj (j =
.., Q) indicate output signals of the source driver 3. Vgon indicates the voltage of the scanning signal line 11 at which the switching element 13 is turned on. Vgoff indicates the voltage of the scanning signal line 11 at which the switching element 13 is completely turned off. V
ij (i = 1, 2, 3,..., p, j = 1, 2, 3,.
.., Q) indicate pixel voltages applied to the data signal line Yj by the source driver 3 when the gate driver 2 scans the scanning signal line Xi. TV scans the entire screen sequentially,
One frame period until the charging voltage to each pixel electrode 10 is updated to data based on the next video signal is shown. TH indicates one scanning period for scanning one scanning signal line.

[0012]

SUMMARY OF THE INVENTION Assuming a liquid crystal display device for a portable terminal, in order to reduce power consumption,
It is conceivable to change the information amount according to the video to be displayed. For example, when displaying natural image information or the like as a multi-tone image signal, for example, a 6-bit image signal is assigned to each of RGB, and approximately 260,000 colors can be displayed on a liquid crystal panel. In addition, when displaying characters or simple character information as a binary video signal, a 1-bit video signal is assigned to each of RGB, so that eight colors can be displayed on the liquid crystal panel.

Consider a case in which a liquid crystal panel 1 displaying a 6-bit video signal at a frame frequency of 60 Hz displays a binary video signal in eight colors. The relationship between the voltage applied by the pixel electrode and the counter electrode and the panel luminance is as follows.
Have characteristics as shown in FIG.

In the conventional active matrix type liquid crystal display device, no matter what kind of image information is displayed on the entire surface of the liquid crystal panel or when only one part of the liquid crystal panel displays information, the image on the liquid crystal panel is displayed. The display frame frequency was fixed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has been made in view of the above-mentioned problems. It is an object of the present invention to realize a liquid crystal display device that can reduce power consumption by lowering the operating frequency of a circuit, and an image display application device and a portable information terminal device equipped with the liquid crystal display device.

[0016]

According to a first aspect of the present invention, there is provided a liquid crystal cell sandwiched between a plurality of pixel electrodes arranged in a row direction and a column direction in pixel units, the pixel electrode and a counter electrode, and A plurality of switching elements having a control output terminal connected to the pixel electrode, a first control input terminal to which a scanning signal is input, a second control input terminal to which a pixel signal for row scanning is applied, A liquid crystal panel provided with a plurality of row direction signal lines connected to one control input terminal, a plurality of column direction signal lines connected to a second control input terminal of the switching element, and the plurality of row direction signal lines A row-direction drive circuit for sequentially outputting the scanning signal, a column-direction drive circuit for outputting a pixel signal corresponding to display data to the plurality of column-direction signal lines, and display data for the column-direction drive circuit. Output movie A liquid crystal comprising: a signal processing circuit; and a control signal generation circuit that outputs a drive control signal to the row direction drive circuit and the column direction drive circuit and outputs a video control signal to the video signal processing circuit. A display device, wherein the control signal generating circuit is configured to, when displaying a multi-gradation video signal on the liquid crystal panel, determine a frame frequency of the multi-gradation video signal and a pixel electrode arranged in a column direction of the liquid crystal panel. , The frequency of the scanning signal and the video display frame frequency are determined, and when displaying a binary video signal on the liquid crystal panel, the frequency of the scanning signal and the video display frame frequency are multi-grayscale, respectively. It is characterized in that the video signal is changed to a lower one when displaying the video signal.

According to a second aspect of the present invention, there are provided a plurality of pixel electrodes arranged in a row direction and a column direction on a pixel basis, a liquid crystal cell sandwiched between the pixel electrode and a counter electrode, and connected to the pixel electrode. A plurality of switching elements having a control output terminal, a first control input terminal to which a scanning signal is input, a second control input terminal to which a pixel signal of row direction scanning is applied, and a first control input terminal of the switching element. A liquid crystal panel provided with a plurality of row direction signal lines connected thereto and a plurality of column direction signal lines connected to a second control input terminal of the switching element; and sequentially applying the scanning signal to the plurality of row direction signal lines. A row direction driving circuit, a column direction driving circuit that outputs a pixel signal corresponding to display data to the plurality of column direction signal lines, and a video signal processing circuit that outputs display data to the column direction driving circuit When A control signal generation circuit that outputs a drive control signal to the row direction drive circuit and the column direction drive circuit and outputs a video control signal to the video signal processing circuit. When the video signal is displayed in a part of the liquid crystal panel in the row direction, the control signal generation circuit controls to change the frequency of the scanning signal according to the number of display rows.

According to a third aspect of the present invention, there are provided a plurality of pixel electrodes arranged in a row direction and a column direction in a pixel unit, a liquid crystal cell sandwiched between the pixel electrode and a counter electrode, and connected to the pixel electrode. A plurality of switching elements having a control output terminal, a first control input terminal to which a scanning signal is input, a second control input terminal to which a pixel signal of row direction scanning is applied, and a first control input terminal of the switching element. A liquid crystal panel provided with a plurality of row direction signal lines connected thereto and a plurality of column direction signal lines connected to a second control input terminal of the switching element; and sequentially applying the scanning signal to the plurality of row direction signal lines. A row direction driving circuit, a column direction driving circuit that outputs a pixel signal corresponding to display data to the plurality of column direction signal lines, and a video signal processing circuit that outputs display data to the column direction driving circuit When A control signal generation circuit that outputs a drive control signal to the row direction drive circuit and the column direction drive circuit and outputs a video control signal to the video signal processing circuit. The control signal generating circuit, when displaying a binary video signal on the liquid crystal panel, outputs a multi-gradation video signal during a period when the switching element turns on the column direction signal line and the pixel electrode. It is characterized in that it is held in the same state as in the case of displaying, and the generation timing of the scanning signal with respect to the row signal lines adjacent to each other is delayed as compared with the case of displaying a multi-tone video signal.

According to a fourth aspect of the present invention, there is provided an image display application apparatus comprising the liquid crystal display device according to any one of the first to third aspects.

According to a fifth aspect of the present invention, there is provided an information portable terminal device comprising the liquid crystal display device according to any one of the first to third aspects.

[0021]

(Embodiment 1) A liquid crystal display device according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the liquid crystal display device of the present invention, and the same parts as those of the conventional example are denoted by the same reference numerals. The internal configurations of the liquid crystal panel 1, the gate driver 2, the source driver 3, and the video signal processing circuit 4 are the same as in the conventional example.

The control signal generation circuit 5A outputs a gate drive control signal to the gate driver 2, outputs a source drive control signal to the source driver 3, and outputs a video circuit control signal to the video signal processing circuit 4. The control signal generation circuit 5A of the present embodiment determines the timings of the gate drive control signal and the source drive control signal based on the information amount of the video signal and the liquid crystal panel 1.
, The drive timing of the entire liquid crystal display device is changed. Specifically, when displaying a multi-tone video signal on the liquid crystal panel 1, the control signal generating circuit 5 </ b> A determines the frame frequency of the multi-tone video signal and the number of pixel electrodes arranged in the column direction of the liquid crystal panel 1. From the above, the frequency of the scanning signal and the video display frame frequency are determined, and when displaying the binary video signal on the liquid crystal panel 1, the frequency of the scanning signal and the video display frame frequency are respectively displayed as the multi-gradation video signal. Change to lower than case.

FIG. 2 shows Xi (i = 1, 2, 3,...,
(p) is a timing chart showing an output signal of the gate driver 2. FIG. 3 is a timing chart showing output signals of the source driver 3 where Yj (j = 1, 2, 3,..., Q). Vgon in FIG. 2 indicates the voltage of the scanning signal line 11 at which the switching element 13 is turned on, and Vgoff indicates the voltage of the scanning signal line 11 at which the switching element 13 is completely turned off. Vij (i = 1, 2, 3,..., P, j = 1, 2,
,..., Q) indicate that the gate driver 2 uses the scanning signal line Xi.
Shows the pixel voltage applied to the data signal line Yj by the source driver 3 when scanning is performed.

TH1 indicates one scanning line selection period in which the gate driver 2 outputs Vgon to any one scanning signal line 11 when the video signal is multi-gradation data, and has a reciprocal relationship with the frequency of the scanning signal. is there. TV1 indicates one frame period from the time when an arbitrary scanning signal line is selected until the next time the same scanning signal line is selected when the video signal is multi-gradation data, and has a reciprocal relationship with the video display frame frequency. . The gate driver 2 selectively scans all the scanning signal lines 11 sequentially during one frame period.

TH2 indicates that when the video signal is binary data,
The gate driver 2 applies Vgo to any one scanning signal line 11.
n indicates one scanning line selection period, and TH2> TH1
It is. TV2 indicates one frame period from selection of an arbitrary scanning signal line to selection of the next scanning signal line when the video signal is binary data, and TV2> TV1.

The control signal generating circuit 5A operates the gate driver 2 and the source driver 3 in accordance with the identification information indicating which of the multi-gradation data and the binary data is supplied in synchronization with the video signal. To change. When the video signal is multi-gradation data, one scanning period is TH
The control signal is output to the gate driver 2 and the source driver 3 so as to be 1 for one frame period.
TV1 is determined by the frame frequency of the video signal input to the liquid crystal display device, and TH1 is determined by TV1 and the number of rows of pixel electrodes in the column direction of the liquid crystal panel 1.

When the video signal is binary data, 1
Assuming that the scanning period is TH2 and one frame period is TV2, a control signal is output to the gate driver 2 and the source driver 3 so that their values are longer than TH1 and TV1, respectively. In this case, if two values of VL and VH are used as the applied voltage to each of the RGB pixels, it can be said that even if the frame frequency is reduced to about 30 Hz, the effect on the display is small. That is, when displaying a binary video signal, even if the signal charge in the liquid crystal cell is slightly reduced, this can be ignored, so that the frame frequency can be reduced.

As described above, when displaying binary data, the frame frequency to be displayed on the liquid crystal panel 1 is changed in accordance with the video signal by lowering the frame frequency as compared with displaying multi-gradation data. be able to. Therefore, the frequency of the input video signal of the liquid crystal display device can be reduced, and the power consumption can be reduced.

When the liquid crystal panel 1 has the characteristics shown in FIG. 9, the pixel applied voltage is V
If the output voltage of the source driver 3 is determined so as to be L and VH, no display problem will occur even if the frame frequency is set to about 1/2 of the multi-gradation data.

(Embodiment 2) Next, a liquid crystal display device according to Embodiment 2 of the present invention will be described. The configuration of the liquid crystal display device is the same as that of FIG.
Is different from the operation of the control signal generation circuit 5. The control signal generation circuit 5B performs control to change the frequency of the scanning signal in accordance with the number of display rows when displaying a video signal in a part of the liquid crystal panel 1 in the row direction.

Here, the operation in the case where an image is displayed only on a part of the liquid crystal panel 1 in the row direction will be described. 4 and 5 are drive timing diagrams of the liquid crystal display device in such a case, and show a case where an image is displayed only between i rows from the display start position. Xi (i = 1, 2, 3,...) In FIG.
, P) and Yj (j = 1, 2, 3,...,
The meanings of q), Vgon, Vgoff, Vij, TH1, and TV1 are the same as those used in the first embodiment.

TH3 indicates that the video signal is binary data,
This is one scanning line selection period when the gate driver 2 outputs Vgon to any one scanning signal line 11 when an image is displayed only on a part of the liquid crystal panel 1 in the row direction. TH
3 can be set to the number obtained by dividing TV1 by the number of partial display lines.
Therefore, the number of gate drive control signals and source drive control signals output from the control signal generation circuit 5B to the gate driver 2 and the source driver 3 can be reduced, and the power consumption of the liquid crystal display device can be reduced.

In the present embodiment, the timing when an image is displayed only in a part of the liquid crystal panel 1 in the row direction with binary data has been described. However, the frame frequency for displaying binary data is reduced as shown in FIG. Alternatively, the timing may be as shown in FIG. 3 or an image may be displayed on only a part of the liquid crystal panel 1 in the row direction using multi-tone data. When displaying a binary video signal on the liquid crystal panel 1, the signal generating circuit 5B may change the frequency of the scanning signal and the video display frame frequency to lower values than when displaying a multi-gradation video signal.

(Embodiment 3) Next, a liquid crystal display device according to Embodiment 3 of the present invention will be described. The configuration of the liquid crystal display device is the same as that of FIG.
Is different from the operation of the control signal generation circuit 5. When displaying a binary video signal on the liquid crystal panel 1, the control signal generating circuit 5C displays a multi-gradation video signal during a period in which the switching element 13 conducts between the column direction signal line and the pixel electrode 10. In this case, the same timing is maintained, and the generation timing of the scanning signal for the adjacent row direction signal lines is delayed as compared with the case of displaying the multi-gradation video signal.

FIGS. 6 and 7 show timings of the present embodiment in which a video signal is displayed by switching between multi-tone data and binary data. Xi (i = 1, 2, 3,...,
p), Yj (j = 1, 2, 3,..., q) in FIG. 7 and the meanings of Vgon, Vgoff, Vij, TH1, TV1, and TV2 are the same as those in the first or second embodiment. is there. As shown in FIG. 7, when the video signal is binary data, the pixel electrode 10 is charged only for one scanning period (TH1) in the case of multi-gradation data. During the period of (TH2-TH1), the switching element 13 controls the data signal line 12 and the pixel electrode 10 to be in a non-conductive state and to cut off the drive output from the source driver 3 to the data signal line 12. Power consumption can be reduced.

When an image is displayed only in a part of the liquid crystal panel 1 in the row direction, when one scanning period is determined according to the number of display rows, the timing for setting the charging period of the pixel electrode 10 to only TH1 is set. It can also be.

As described above, the control signal generation circuits 5A to 5A
C indicates the frequency of the scanning signal and the video display based on the frame frequency of the multi-tone video signal and the number of pixel electrodes arranged in the column direction of the liquid crystal panel when displaying the multi-tone video signal on the liquid crystal panel 1. Determine the frame frequency.

The liquid crystal display device as described above can be used for an image display application device or a portable information terminal device. In an image display application device such as a notebook personal computer driven by a battery, or an information portable terminal device such as a PDA or a mobile phone, 1
The battery life for each charge is an evaluation target of the portable device. In such a case, the present invention is an effective means for extending the life of the battery.

[0039]

According to the present invention, the power consumption of the liquid crystal display device can be reduced by changing the scanning line selection time and the frame frequency in accordance with the amount of video information and the number of display lines.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a liquid crystal display device according to Embodiments 1 to 3 of the present invention.

FIG. 2 is a timing chart showing an operation (1) of the liquid crystal display device in Embodiment 1.

FIG. 3 is a timing chart showing an operation (part 2) of the liquid crystal display device in Embodiment 1.

FIG. 4 is a timing chart showing an operation (No. 1) of the liquid crystal display device in Embodiment 2.

FIG. 5 is a timing chart showing an operation (part 2) of the liquid crystal display device in Embodiment 2.

FIG. 6 is a timing chart showing an operation (1) of the liquid crystal display device in Embodiment 3.

FIG. 7 is a timing chart showing an operation (part 2) of the liquid crystal display device in Embodiment 3.

FIG. 8 is an overall configuration diagram of a conventional liquid crystal display device.

FIG. 9 is a characteristic diagram illustrating a relationship between a voltage applied to a pixel electrode and luminance in a liquid crystal display panel.

FIG. 10 is an operation timing chart of a conventional liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Gate driver 3 Source driver 4 Video signal processing circuit 5A, 5B, 5C Control signal generation circuit 10 Pixel electrode 11 Scan signal line 12 Data signal line 13 Switching element 14 Counter electrode X1, X2, Xi, Xp Scan signal line Y1, Y2, Yj, Yq Data signal lines V11, V21, Vij, V12, V22, Vi2, Vij, V2j, V
ij, V1q, V2q, Viq Output voltage of source driver TH1 One scan line selection period for multi-level data TH2 One scan line selection period for multi-level data TV1 One frame period for multi-level data TV2 For two-level data One frame period

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) G09G 3/20 621 G09G 3/20 621A 622 622D 660 660V (72) Inventor Takashi Tsukada Kazuma Kadoma, Osaka Prefecture 1006 F-term in Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] A plurality of pixel electrodes arranged in a row direction and a column direction in pixel units; a liquid crystal cell sandwiched between the pixel electrode and a counter electrode; a control output terminal connected to the pixel electrode;
A plurality of switching elements having a first control input terminal to which a scanning signal is input, a second control input terminal to which pixel signals for row scanning are applied, and a plurality of switching elements connected to a first control input terminal of the switching element A liquid crystal panel provided with a plurality of column direction signal lines connected to a row direction signal line and a second control input terminal of the switching element; and a row for sequentially outputting the scanning signal to the plurality of row direction signal lines. A direction driving circuit; a column direction driving circuit that outputs a pixel signal corresponding to display data to the plurality of column direction signal lines; a video signal processing circuit that outputs display data to the column direction driving circuit; A control signal generating circuit that outputs a driving control signal to the direction driving circuit and the column direction driving circuit and outputs a video control signal to the video signal processing circuit. The control signal generating circuit, when displaying a multi-gradation video signal on the liquid crystal panel, determines a frame frequency of the multi-gradation video signal and the number of pixel electrodes arranged in a column direction of the liquid crystal panel. Determining a frequency of the scanning signal and a video display frame frequency, and displaying a multi-gradation video signal by displaying the frequency of the scanning signal and the video display frame frequency when displaying a binary video signal on the liquid crystal panel. A liquid crystal display device characterized by changing to a lower value than when performing the above. 2. A plurality of pixel electrodes arranged in a row direction and a column direction in a pixel unit, a liquid crystal cell sandwiched between the pixel electrode and a counter electrode, a control output terminal connected to the pixel electrode,
A plurality of switching elements having a first control input terminal to which a scanning signal is input, a second control input terminal to which pixel signals for row scanning are applied, and a plurality of switching elements connected to a first control input terminal of the switching element A liquid crystal panel provided with a plurality of column direction signal lines connected to a row direction signal line and a second control input terminal of the switching element; and a row for sequentially outputting the scanning signal to the plurality of row direction signal lines. A direction driving circuit; a column direction driving circuit that outputs a pixel signal corresponding to display data to the plurality of column direction signal lines; a video signal processing circuit that outputs display data to the column direction driving circuit; A control signal generating circuit that outputs a driving control signal to the direction driving circuit and the column direction driving circuit and outputs a video control signal to the video signal processing circuit. Wherein the control signal generating circuit controls the frequency of the scanning signal in accordance with the number of display rows when displaying the video signal in a part of the liquid crystal panel in a row direction. Display device. 3. A plurality of pixel electrodes arranged in a row direction and a column direction on a pixel basis, a liquid crystal cell sandwiched between the pixel electrode and a counter electrode, a control output terminal connected to the pixel electrode,
A plurality of switching elements having a first control input terminal to which a scanning signal is input, a second control input terminal to which pixel signals for row scanning are applied, and a plurality of switching elements connected to a first control input terminal of the switching element A liquid crystal panel provided with a plurality of column direction signal lines connected to a row direction signal line and a second control input terminal of the switching element; and a row for sequentially outputting the scanning signal to the plurality of row direction signal lines. A direction driving circuit; a column direction driving circuit that outputs a pixel signal corresponding to display data to the plurality of column direction signal lines; a video signal processing circuit that outputs display data to the column direction driving circuit; A control signal generating circuit that outputs a driving control signal to the direction driving circuit and the column direction driving circuit and outputs a video control signal to the video signal processing circuit. The control signal generating circuit, when displaying a binary video signal on the liquid crystal panel, sets a period during which the column-direction signal line and the pixel electrode are electrically connected by the switching element, as a multi-gradation video signal. Wherein the display signal is held in the same state as in the case of displaying, and the generation timing of the scanning signal with respect to the adjacent row direction signal lines is delayed as compared with the case of displaying the multi-gradation video signal. 4. An image display application device comprising the liquid crystal display device according to claim 1. 5. An information portable terminal device equipped with the liquid crystal display device according to claim 1.