JP2007304522A - Electrooptical device and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical device capable of reducing power consumption in driving a display panel in the nondisplay state. <P>SOLUTION: The electrooptical device comprises a display part having a plurality of display regions, a plurality of signal lines, and a plurality of scanning lines; a scanning line driving circuit; a signal line driving circuit; and a control part. The plurality of signal lines are shared by the plurality of the display regions. The plurality of the scanning lines are provided to the plurality of the display regions, respectively. When a first display region of the plurality of the display regions is put into the display state, and a second display region is put into the nondisplay state, the control part of the electrooptical device supplies a predetermined voltage to all of the plurality of the signal lines simultaneously in the nondisplay period in one frame period, in which the second display region is in the nondisplay state, and supplies scanning signals to all of the plurality of the scanning lines in the other display region simultaneously. Thereby, power consumption can be reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electro-optical device suitable for displaying various information.

Recently, so-called double-sided display type mobile phones have become widespread. In a foldable mobile phone, a display unit (corresponding to the lid side in terms of structure) is generally attached to a main body provided with operation buttons and the like so as to be hinged. A large main display panel is provided on the inner side (side facing the operation buttons), and a small sub display panel is provided on the outer side (back side) of the display unit. That is, the main display panel and the sub display panel are provided back to back. For example, a liquid crystal display panel is used as the main display panel and the sub display panel.

The liquid crystal display panel has source lines and gate lines arranged in a matrix, and a switching element and a pixel electrode are provided at each intersection where the source line and the gate line intersect, and a counter electrode is opposed to the pixel electrode. The liquid crystal layer is provided between the pixel electrode and the counter electrode.

Conventionally, the main display panel and the sub display panel are each driven by separate drive circuits, but recently, a display device that drives both the main display panel and the sub display panel with one drive circuit has also appeared. .

Even when both the main and sub display panels are driven by such a single drive circuit, an image can be displayed on one display panel and the other display panel can be hidden.
Since the drive circuit is shared, the other display panel that is not displayed is charged with charge when one of the display panels is displayed. Therefore, it is necessary to drive the other display panel that is not displayed in order to discharge the charged electric charge.

In the conventional liquid crystal display device, since the counter electrode driving circuit drives both the counter electrodes of the main display panel and the sub display panel with the same control signal, the counter electrode of the main display panel is opposed to the sub display panel. The electrodes could not be controlled independently. For this reason, the counter electrode driving circuit always performs AC driving for each horizontal period, and power consumption increases even when a non-displayed display panel is driven.

In the liquid crystal display device described in Patent Document 1 below, the counter electrode driving circuit is driven by different control signals depending on whether the display panel that is displayed is driven or the display panel that is not displayed is driven. In the case of driving a non-displayed display panel, the driving frequency is reduced and the power consumption is suppressed by performing AC driving of the counter electrode every vertical period.

JP-A-2005-91629

However, in the liquid crystal display device described in Patent Document 1, when driving a non-displayed display panel, the gate line driving circuit sequentially supplies gate signals to the gate lines exclusively every horizontal period. The power consumption was not reduced enough.

The present invention has been made in view of the above points, and an object thereof is to provide an electro-optical device that can further suppress power consumption in driving a non-displayed display panel.

In one aspect of the present invention, an electro-optical device includes a plurality of display areas, a plurality of signal lines common to the plurality of display areas, and a plurality of scanning lines provided in each of the plurality of display areas. A display unit, a scanning line driving circuit for supplying scanning signals to the plurality of scanning lines for each of the plurality of display areas, a signal line driving circuit for supplying signals to the plurality of signal lines, and the scanning line driving A control unit that controls the circuit and the signal line driving circuit, and when the first display region is set to the display state and the second display region is set to the non-display state among the plurality of display regions, the control unit In the display period in which the first display area is in a display state during one frame period, the signals are sequentially supplied to the plurality of scanning lines in the first display area while supplying the signals to the plurality of signal lines. Supplying a scanning signal to the second display area; In the non-display period and non-display state, supplying simultaneously scan signals to the all of the plurality of scanning lines of said second display region is supplied simultaneously a predetermined voltage to all of said plurality of signal lines.

The electro-optical device includes a display unit including a plurality of display regions, a plurality of signal lines, and a plurality of scanning lines, a scanning line driving circuit, a signal line driving circuit, and a control unit. The plurality of signal lines are common to the plurality of display areas. The plurality of scanning lines are provided in each of the plurality of display areas. The scanning line driving circuit supplies a scanning signal to the plurality of scanning lines for each of the plurality of display areas. The signal line driver circuit supplies a signal to the plurality of signal lines. The control unit controls the scanning line driving circuit and the signal line driving circuit.

The electro-optical device is, for example, a double-sided display type liquid crystal display device. In this case, the plurality of display areas correspond to, for example, a sub display panel and a main display panel. The plurality of signal lines and the signal line driving circuit correspond to, for example, a plurality of source lines and a source line driving circuit, respectively, and the plurality of scanning lines and the scanning line driving circuit include, for example, a plurality of gate lines and gate line driving. Each corresponds to a circuit.

In the electro-optical device, when the first display area is set to the display state and the second display area is set to the non-display state among the plurality of display areas, the control unit includes the first display area in the one frame period. 1
In the display period in which the display area is in the display state, the second display is performed by sequentially supplying scanning signals to the plurality of scanning lines in the first display area while supplying the signals to the plurality of signal lines. In a non-display period in which the area is in a non-display state, a predetermined voltage is supplied to all of the plurality of signal lines at the same time, and a scanning signal is supplied to all of the plurality of scanning lines in the second display area at the same time. To do.

As a result, the electro-optical device described above is compared with a general double-sided display type liquid crystal display device.
In one frame period, the time required for refreshing the charge can be shortened, and accordingly, a period for displaying an image in the display region to be displayed can be lengthened.
For example, in order to discharge the charge charged in the non-displayed display region, the charge refreshing is performed by using a scanning line to send a signal indicating that the potential of the pixel electrode in the non-displayed display region is off level. However, the present invention is not limited to this. Instead, a predetermined scanning signal is supplied to the scanning line, and a predetermined voltage is supplied to the signal line, so that the non-display state is established. It also means that the charge charged in the display area is made uniform throughout the display area in the non-display state.

By doing so, each drive of the scanning signal supplied to the plurality of scanning lines, the signal supplied to the plurality of signal lines, and the clock signal for displaying an image in the display area to be displayed is performed. The frequency can be lowered and the power consumption can be reduced.

In another aspect of the electro-optical device, the non-display period is a vertical blanking period, and the display period is a period other than the vertical blanking period in the one frame period. Accordingly, the electro-optical device can use a period other than the vertical blanking period in one frame period for displaying an image in the display area that is in the display state. Therefore, each drive frequency of the scanning signal supplied to the plurality of scanning lines, the signal supplied to the plurality of signal lines, and the clock signal for displaying an image in the display area to be displayed is maximized. Can be lowered.

In another aspect of the present invention, an electronic apparatus including the above liquid crystal display device in a display portion can be configured.

In still another aspect of the present invention, a display unit including a plurality of display areas, a plurality of signal lines common to the plurality of display areas, and a plurality of scanning lines provided in each of the plurality of display areas. A scanning line driving circuit for supplying a scanning signal to the plurality of scanning lines for each of the plurality of display areas;
An electro-optical device driving method comprising: a signal line driving circuit that supplies signals to the plurality of signal lines; and a control unit that controls the scanning line driving circuit and the signal line driving circuit. When the first display area is set to the display state and the second display area is set to the non-display state, the control unit is configured to display the first display area in the display period during one frame period. In a non-display period in which the scanning signal is sequentially supplied to the plurality of scanning lines in the first display region while the signal is supplied to the plurality of signal lines, and the second display region is in a non-display state. Supplies a predetermined voltage simultaneously to all of the plurality of signal lines and simultaneously supplies a scanning signal to all of the plurality of scanning lines in the second display area.

The driving method of the electro-optical device can also reduce the time required for refresh during one frame period, and accordingly, increase the period for displaying an image in the display area to be displayed. Can do. Therefore, it is possible to lower the respective driving frequencies of the scanning signal supplied to the plurality of scanning lines, the signal supplied to the plurality of signal lines, and the clock signal for displaying an image in the display area to be displayed. And power consumption can be reduced.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the present invention is applied to a liquid crystal display device. The liquid crystal display device 100 according to the present embodiment has the same configuration as that of a general double-sided display type liquid crystal display device except for the drive circuit.

[Liquid Crystal Display]
FIG. 1 is a side view showing a schematic configuration of a liquid crystal display device 100 according to the present embodiment. In FIG. 1, for convenience of explanation, each component is illustrated with a space therebetween, but actually, the liquid crystal display device 100 is configured in a state where they are stacked in the vertical direction in the drawing.

The liquid crystal display device 100 is a so-called double-sided display type panel, in which liquid crystal display panels 20 and 30 are arranged above and below one lighting device 9 constituted by a light source unit 15 and a light guide plate 11.
The light source unit 15 includes a plurality of LEDs 16 that are point light sources. The light L emitted from each LED 16 enters the light guide plate 11 as shown in the figure, and changes its direction by repeating reflection on the upper and lower surfaces of the light guide plate 11, and is externally applied as illumination lights La and Lb from the upper and lower surfaces of the light guide plate 11. To exit.

The liquid crystal display panel 20 corresponds to a main display panel in a double-sided display type mobile phone,
The display area is almost the same as the light emission area of the light guide plate 11. The liquid crystal display panel 20 is configured by laminating substrates 1a and 2a such as glass through a sealing material 3a to form a cell structure and enclosing the liquid crystal 4a therein.

An optical sheet 12 a is provided between the illumination device 9 and the liquid crystal display panel 20. The optical sheet 12a is a diffusion sheet or a prism sheet. The diffusion sheet has a role of diffusing the light La emitted from the light guide plate 11, and the prism sheet is the light La emitted from the light guide plate 11.
Is emitted toward the liquid crystal display panel 20. The light La emitted from the light guide plate 11 illuminates the liquid crystal display panel 20 through the optical sheet 12a.

On the other hand, the liquid crystal display panel 30 is smaller than the liquid crystal display panel 20, and the liquid crystal display panel 2.
The panel has a display area smaller than zero. The liquid crystal display panel 30 corresponds to a sub display panel (a small display panel provided on the back of the main display panel) in terms of a double-sided display type mobile phone. The liquid crystal display panel 30 is also configured by bonding substrates 1b and 2b such as glass through a sealing material 3b and enclosing the liquid crystal 4b therein.

An optical sheet 12 b such as a diffusion sheet or a prism sheet is also provided between the liquid crystal display panel 30 and the light guide plate 10. The light Lb emitted from the light guide plate 11 illuminates the liquid crystal display panel 30 through the optical sheet 12b.

The liquid crystal display panel 20 is directly mounted with a driver IC 40 as a liquid crystal driving IC (driver) by COG (Chip On Glass) technology. In addition, an output terminal 17 a is mounted on the liquid crystal display panel 20, and an input terminal 17 b is mounted on the liquid crystal display panel 30. The liquid crystal display panel 30 includes an FPC (Flexible Printed Circuit) that connects the output terminal 17a and the input terminal 17b.
cuit) 13 and is electrically connected to the liquid crystal display panel 20. As will be described in detail later, the source lines of the liquid crystal display panel 30 are electrically connected to the source lines of the liquid crystal display panel 20 via the FPC 13, and the source lines of the liquid crystal display panels 20 and 30 are driven by the driver IC 40.

Next, the configuration of the drive circuit of the liquid crystal display panels 20 and 30 will be specifically described. FIG. 2 is a plan view schematically showing a schematic configuration of the liquid crystal display panels 20 and 30 according to the present embodiment. The liquid crystal display panels 20 and 30 are active matrix drive type liquid crystal display devices using switching elements such as TFT elements (Thin Film Transistors). In FIG. 2, the vertical direction (column direction) of the paper surface is defined as the Y direction, and the horizontal direction (row direction) of the paper surface is defined as the X direction.

First, the configuration of the drive circuit of the liquid crystal display panel 20 will be described. The liquid crystal display panel 20
As described above, the substrates 1a and 2a are bonded to each other through the sealing material 3a to form a cell structure, and the liquid crystal 4a is enclosed therein. In FIG. 2, the liquid crystal 4a and the sealing material 3
Illustration of a is omitted.

On the inner surface of the substrate 1a, a plurality of source lines 32a, a plurality of gate lines 33a, and a plurality of TFTs are provided.
An element 51, a plurality of pixel electrodes 52, a driver IC 40, a gate line driving circuit 21a, an output terminal 17a, and the like are formed or mounted.

The substrate 1a has a region extending outward from one end side of the substrate 2a, and a driver IC 40 is mounted on the region. The driver IC 40 is connected to an external electronic device via the wiring 35. The plurality of source lines 32a are formed so as to extend in the Y direction and at appropriate intervals in the X direction. One end of each of the plurality of source lines 32 a is electrically connected to the driver IC 40. Among the plurality of source lines 32a, some of the source lines 32
a is the other end of the source line 32 of the liquid crystal display panel 30 via the FPC 13 from the output terminal 17a.
electrically connected to b. Accordingly, the driver IC 40 includes the liquid crystal display panels 20 and 30.
Functions as a source line driver circuit.

The substrate 1a has a region extending in the X direction, and a gate line driving circuit 21a is mounted on the region. GA1, GA2,..., GAm (m: natural number)
The plurality of m gate lines 33a are formed so as to extend in the X direction and at appropriate intervals in the Y direction, and to be orthogonal to the plurality of source lines 32a. One end of each of the plurality of gate lines 33a is electrically connected to the gate line driving circuit 21a.

A TFT element 51 is provided at a position where each source line 32a and each gate line 33a intersect, and the TFT element 51 is electrically connected to each source line 32a, each gate line 33a, and the pixel electrode 52. The pixel electrode 52 is formed of a transparent conductive material such as ITO (Indium-Tin Oxide).

On the other hand, on the inner surface of the substrate 2a facing the substrate 1a, a color filter is formed at a position corresponding to the pixel electrode 52, and a light shielding layer is formed at a position partitioning the color filter.
A counter electrode 8a is formed on substantially one surface on the inner surface of the substrate 2a using ITO or the like. In FIG. 2, the color filter and the light shielding layer are not shown, and only the counter electrode 8a is indicated by a broken line.

Next, the configuration of the drive circuit of the liquid crystal display panel 30 will be described. The liquid crystal display panel 30 is
As described above, the substrates 1b and 2b are bonded to each other through the sealing material 3b to form a cell structure, and the liquid crystal 4b is sealed therein. In FIG. 2, the liquid crystal 4b and the sealing material 3
Illustration of b is omitted.

On the inner surface of the substrate 1b, a plurality of source lines 32b, a plurality of gate lines 33b, and a plurality of TFTs
An element 51, a plurality of pixel electrodes 52, a gate line driving circuit 21b, an input terminal 17b, and the like are formed or mounted.

The plurality of source lines 32b are formed so as to extend in the Y direction and at appropriate intervals in the X direction. One end of each of the plurality of source lines 32b is connected to a part of the source lines 32a of the liquid crystal display panel 20 through the FPC 13 from the input terminal 17b. The substrate 1b has a region extending in the X direction, and a gate line driving circuit 21b is mounted on the region. A plurality of gate lines 33b indicated by GB1, GB2,..., GBn (n: natural number).
Are formed so as to extend in the X direction and at an appropriate interval in the Y direction, and to be orthogonal to the plurality of source lines 32b. One end of each of the plurality of gate lines 33b is electrically connected to the gate line driving circuit 21b.

A TFT element 51 is also provided at a position where each source line 32 b and each gate line 33 b intersect. The TFT element 51 is electrically connected to each source line 32 b, each gate line 33 b, and the pixel electrode 52. On the inner surface of the substrate 2b facing the substrate 1b, a color filter is formed at a position corresponding to the pixel electrode 52, and a light shielding layer is formed at a position partitioning the color filter. A counter electrode 8b is formed on substantially one surface on the inner surface of the substrate 2b using ITO or the like. In FIG. 2, the color filter and the light shielding layer are not shown, and only the counter electrode 8b is indicated by a broken line.

The counter electrodes 8a and 8b are electrically connected to the driver IC 40 by wiring, and the driver IC supplies a drive signal VCOM to the counter electrodes 8a and 8b. Therefore, the driver IC also functions as a counter electrode driving circuit.

The driver IC 40 is electrically connected to the gate line driving circuit 21a and the gate line driving circuit 21b through various wirings (not shown). The driver IC 40 supplies various control signals to the gate line driving circuits 21a and 21b based on signals supplied from external electronic devices. That is, the driver IC 40 functions as a control circuit that controls driving of the liquid crystal display device 100, that is, a control unit in the present invention.

Specifically, the driver IC 40 sends the clock signal CLK to the gate line driving circuits 21a, 2
To 1b. The driver IC 40 supplies the start signal STV1 to the gate line driving circuit 21b and the start signal STV2 to the gate line driving circuit 21a. The start signal here is a start signal of one frame.

The gate line drive circuits 21a and 21b are also electrically connected by wiring, and the gate line drive circuits 21a and 21b can exchange the cascade signal CAS with each other. Specifically, the gate line driving circuit of one liquid crystal display panel finishes supplying the gate signals to all the gate lines in the one liquid crystal display panel, and then sends the cascade signal CAS to the gate line of the other liquid crystal display panel. Supply to the drive circuit. After receiving the cascade signal CAS, the gate line driving circuit of the other liquid crystal display panel starts supplying a gate signal to the gate line of the other liquid crystal display panel. That is, the cascade signal CAS is a signal for notifying the gate line driving circuit of the other liquid crystal display panel that the image display on one liquid crystal display panel is finished.

As a feature of the liquid crystal display device 100 according to the present embodiment, the driver IC 40 supplies the all gate on signal AON1 to the gate line driving circuit 21b and supplies the all gate on signal AON2 to the gate line driving circuit 21a. As will be described in detail later, all gate-on signal AON here
1 is a control signal for instructing the gate line drive circuit 21b to supply gate signals to all the gate lines 33b all at once, and the all gate-on signal AON2 is all for the gate line drive circuit 21a. This is a control signal for instructing the simultaneous supply of gate signals to the gate line 33a.

(Driving method for two-screen display)
Next, a driving method in the liquid crystal display device 100 having the above configuration will be described.

First, when the liquid crystal display device 100 performs two-screen display, that is, the liquid crystal display panels 20 and 3.
A driving method in the case of displaying an image on both 0 will be described. FIG. 3 shows a liquid crystal display device 100.
Shows a driving sequence when two-screen display is performed.

In FIG. 3, the source line 3 is driven by a driver IC 40 that functions as a source line driving circuit.
The source signal supplied to 2a and 32b is shown as SCE. In the liquid crystal display device 100 according to the present embodiment, line inversion driving that inverts the potentials of the counter electrodes 8a and 8b for each line is employed, and VCOM is inverted for each line. Therefore, along with this, SCE
Invert every line. In FIG. 3, GB1, GB2,..., GBn, GA1, GA
2..., GAm drive signal waveforms are GB1, GB2,..., GBn in FIG.
, GA1, GA2,..., GAm indicate whether or not a gate signal is supplied to each gate line, and the waveform when the gate signal is supplied to each gate line is shown as a rectangular wave.

First, in the liquid crystal display panel 30, when the gate line driving circuit 21b receives the start signal STV1 from the driver IC 40, the gate line 33b sequentially and exclusively selects the gate lines 33b in the order of GB1, GB2,..., GBn−1, GBn. A gate signal is supplied to the selected gate line 33b. Specifically, the gate line drive circuit 21b includes the selected gate line 33b.
A gate signal of a selection voltage is supplied, and a gate signal of a non-selection voltage is supplied to the other non-selection gate line 33b. That is, supplying a gate signal to the gate line means supplying a gate signal of a selection voltage to the gate line. That is, in FIG. 3, the waveform of the gate signal of the selection voltage is shown as a rectangular wave.

The driver IC 40 functioning as a source line driving circuit sends a source signal corresponding to the display content to each of the source lines 3 for the pixel electrode 52 existing at a position corresponding to the selected gate line 33b.
2b, supplied through the TFT element 51. Thereby, the display state of the liquid crystal 4b in the liquid crystal display panel 30 is switched to the non-display state or the intermediate display state, and the alignment state of the liquid crystal molecules in the liquid crystal 4b is controlled. Can be displayed. The driving sequence at this time is shown as a display period of the liquid crystal display panel 30 in FIG.

After the gate line driving circuit 21b finishes supplying the gate signal to the gate line 33b of GBn,
That is, after displaying a desired image on the liquid crystal display panel 30, the gate line driving circuit 21.
A cascade signal CAS is supplied to a. When the gate line driving circuit 21a receives the cascade signal CAS, the gate line 33a in the order of GA1, GA2,..., GAm−1, GAm.
Are sequentially selected and a gate signal is supplied to the selected gate line 33a.
Then, the driver IC 40 functioning as a source line driving circuit is connected to the selected gate line 33.
A source signal corresponding to the display content is supplied to the pixel electrode 52 located at a position corresponding to a through each source line 32 a and the TFT element 51. As a result, the display state of the liquid crystal 4a in the liquid crystal display panel 20 is switched to the non-display state or the intermediate display state, and the alignment state of the liquid crystal molecules in the liquid crystal 4a is controlled. Can be displayed. The driving sequence at this time is shown in FIG.
It is shown as a display period.

The operation described above is performed for one frame period (for example, 16.7 msec (60H in FIG. 3).
z) is performed during one frame period), the liquid crystal display device 100 can display a desired image on both the liquid crystal display panels 20 and 30.

(Driving method for displaying only the sub display panel)
Next, when the liquid crystal display device 100 performs one-screen display, that is, the liquid crystal display panels 20 and 30.
A driving method in the case where an image is displayed on only one of them will be described. First, a driving method for displaying an image only on the liquid crystal display panel 30 as a sub display panel will be described. FIG. 4 shows a driving sequence of the liquid crystal display device 100 when an image is displayed only on the liquid crystal display panel 30 and the liquid crystal display panel 20 is not displayed.

In this case, in the liquid crystal display panel 30, the gate line driving circuit 21b is connected to the driver IC 4
When the start signal STV1 is received from 0, GB1, GB2,..., GBn−1, GBn
The gate lines 33b are selected exclusively in this order, and a gate signal is supplied to the selected gate line 33b. Then, the driver IC 40 functioning as a source line driving circuit sends a source signal corresponding to the display content to the pixel electrode 52 existing at the position corresponding to the selected gate line 33 b via each source line 32 b and the TFT element 51. Supply. As a result, the display state of the liquid crystal 4b in the liquid crystal display panel 30 is switched to the non-display state or the intermediate display state, and the alignment state of the liquid crystal molecules in the liquid crystal 4b is controlled.
A desired image can be displayed at. The drive sequence at this time is shown in FIG.
The display period of the liquid crystal display panel 30 is shown.

Here, the source line 32 a of the liquid crystal display panel 20 and the source line 32 of the liquid crystal display panel 30.
Since b is electrically connected by the FPC 13 as described above, even when the liquid crystal display panel 20 is not displayed, the source signal supplied to the source line 32b of the liquid crystal display panel 30 is It is also supplied to the source line 32a of the liquid crystal display panel 20. For this reason, the charge is also charged to the pixel electrode 52 and the counter electrode 8a of the liquid crystal display panel 20 that is not displayed. Therefore, the pixel electrode 52 is also applied to the liquid crystal display panel 20 that is not displayed.
And since it is necessary to refresh the charge charged in the counter electrode 8a, it is necessary to drive.

To refresh the charge, for example, in order to discharge the charge charged in the non-displayed liquid crystal display panel, a predetermined gate signal is applied to the gate line so that the potential of the pixel electrode 52 becomes an off level. This means that the source signal set to the level is supplied to the source line, but is not limited to this. Instead, a predetermined gate signal is supplied to the gate line, and a source signal of a predetermined voltage is supplied to the source line. By doing so, it also means that the charge charged to the non-displayed liquid crystal display panel is made uniform throughout the non-displayed liquid crystal display panel as a whole.

In the liquid crystal display device 100 according to the present embodiment, the driver IC 40 includes the liquid crystal display panel 30.
In the case of discharging a charge as a refresh of the charge, for example, during a predetermined period after the display of the desired image, that is, a predetermined period after the display period of the liquid crystal display panel 30 is finished. The drive signal for the counter electrode 8a of the liquid crystal display panel 20 is set to the off level, and the source signals set to the off level for refreshing all the source lines 32a are supplied all at once. At this time, the driver IC 40 supplies the all gate on signal AON2 to the gate line driving circuit 21a. When the gate line drive circuit 21a receives the all-gate-on signal AON2, it supplies all the gate lines 33a with gate signals for performing refresh all at once. In this way, the charges charged in the pixel electrode 52 and the counter electrode 8a of the liquid crystal display panel 20 are refreshed. In FIG. 4, for example, the charge refresh is performed in the vertical blanking period, and the driving sequence at this time is shown in the vertical blanking period.

In a general double-sided display type liquid crystal display device, in order to refresh charges, the gate lines 33a are selected exclusively in order of GA1, GA2,. In contrast, the refresh gate signal is supplied to the selected gate line 33a. In the liquid crystal display device 100 according to the present embodiment, the refresh gate signal is simultaneously applied to all the gate lines 33a. By supplying, the charges charged in the pixel electrode 52 and the counter electrode 8a of the liquid crystal display panel 20 are refreshed. Therefore, the liquid crystal display device 100 according to the present embodiment can reduce the time required for refreshing as compared with a general double-sided display type liquid crystal display device.

By doing in this way, the liquid crystal display device 100 according to the present embodiment can reduce the time required for refresh in one frame period as compared with a general double-sided display type liquid crystal display device. Accordingly, the period for displaying an image on the liquid crystal display panel 30 can be increased. Therefore, the liquid crystal display device 100 according to the present embodiment has a gate line 33b for displaying an image on the liquid crystal display panel 30 as compared with a general double-sided display type liquid crystal display device.
Each drive frequency of the gate signal supplied to the source signal, the source signal supplied to the source line 32b, and the clock signal can be lowered. Therefore, the liquid crystal display device 100 according to the present embodiment can realize a reduction in power consumption as compared with a general double-sided display type liquid crystal display device.

As shown in FIG. 4, as a period for refreshing the charges charged in the pixel electrode 52 and the counter electrode 8a of the liquid crystal display panel 20, a vertical blanking period that is not a display period of the liquid crystal display panel is desirable. By doing in this way, the liquid crystal display device 100 according to the present embodiment is
A period other than the vertical blanking period in one frame period, that is, the entire image display period can be used for display of the liquid crystal display panel 30, and each drive of the gate signal, source signal, and clock signal at that time is performed. The frequency can be reduced to the maximum. However, the period in which the charge refresh is performed is not limited to the vertical blanking period, but may be performed in a predetermined period other than the vertical blanking period instead.

(Driving method when only the main display panel is displayed)
Next, a driving method for displaying an image only on the liquid crystal display panel 20 as the main display panel will be described. In FIG. 5, an image is displayed only on the liquid crystal display panel 20, and the liquid crystal display panel 30 is displayed.
The drive sequence of the liquid crystal display device 100 in the case of non-displaying is shown.

In this case, in the liquid crystal display panel 20, the gate line driving circuit 21b is connected to the driver IC 4
When the start signal STV2 is received from 0, GA1, GA2,..., GAm-1, GAm
The gate lines 33a are selected exclusively in this order, and a gate signal is supplied to the selected gate line 33a. Then, the driver IC 40 functioning as a source line driving circuit sends a source signal corresponding to the display content to the pixel electrode 52 existing at a position corresponding to the selected gate line 33 a via each source line 32 a and the TFT element 51. Supply. Thereby, the display state of the liquid crystal 4a in the liquid crystal display panel 20 is switched to the non-display state or the intermediate display state, and the alignment state of the liquid crystal molecules in the liquid crystal 4a is controlled.
A desired image can be displayed at. The drive sequence at this time is shown in FIG.
The display period of the liquid crystal display panel 20 is shown.

The driver IC 40 performs charge refresh during a predetermined period after displaying a desired image on the liquid crystal display panel 20, that is, during a predetermined period after finishing the display period of the liquid crystal display panel 20. For example, when discharging electric charges, the drive signal of the counter electrode 8b of the liquid crystal display panel 30 is set to, for example, an off level, and source signals set to an off level for refreshing all the source lines 32b are set. Supply all at once. At this time, driver I
C40 supplies the entire gate-on signal AON1 to the gate line driving circuit 21b. When the gate line driving circuit 21b receives the all gate-on signal AON1, all the gate lines 33b are received.
The gate signals for refreshing are supplied all at once. In this way, the charges charged in the pixel electrode 52 and the counter electrode 8b of the liquid crystal display panel 30 are refreshed. FIG.
Then, as an example, the refresh is performed in the vertical blanking period, and the driving sequence at this time is shown in the vertical blanking period.

In the liquid crystal display device 100 according to the present embodiment, even when an image is displayed only on the liquid crystal display panel 20 as a main display panel, the time required for refresh can be shortened during one frame period. The period for displaying an image on the display panel 20 can be extended, and the drive frequency of the gate signal supplied to the gate line 33a of the liquid crystal display panel 20, the source signal supplied to the source line 32a, and the clock signal is lowered. Can do.

(Flowchart for driving method of liquid crystal display device)
Next, a driving method of the liquid crystal display device 100 according to the present embodiment will be described based on the flowchart shown in FIG. FIG. 6 is a flowchart showing a driving method of the liquid crystal display device 100, specifically, a flowchart showing a driving method of the liquid crystal display device 100 in the vertical blanking period.

First, the driver IC 40 determines whether or not the current time in one frame period is in the vertical blanking period (step S11). When the driver IC 40 determines that the current time is not in the vertical blanking period (step S11: No), the drive sequence in the display period of the liquid crystal display panels 20 and 30 shown in FIGS. As shown in (5), driving for normal display is performed (step S18). When the driver IC 40 determines that the time is in the vertical blanking period (step S11: Yes), the driving mode of the liquid crystal display device 100 performs a two-screen display based on a signal from an external electronic device. It is determined whether or not the mode is set (step S12).

If the driver IC 40 determines that the driving mode of the liquid crystal display device 100 is a driving mode for performing two-screen display (step S12: Yes), the driver IC 40 does not need to be refreshed, and thus ends the process. If the driver IC 40 determines that the driving mode of the liquid crystal display device 100 is not the driving mode for performing the two-screen display (step S12: No).
) Based on a signal from an external electronic device, it is determined whether or not the driving mode of the liquid crystal display device 100 is a driving mode for displaying only the sub display panel (step S13).

If the driver IC 40 determines that the driving mode of the liquid crystal display device 100 is a driving mode for displaying only the sub display panel (step S13: Yes), whether or not to refresh the main display panel is determined. Judgment based on signals from external electronic devices (
If it is determined that there is no need to perform (step S16) (step S16: No), the process is terminated. If the driver IC 40 determines that the main display panel needs to be refreshed (step S16: Yes), the liquid crystal display panel 2 as the main display panel
A source signal for refreshing and a drive signal VCOM are supplied to all of the zero source lines 32a and the counter electrode 8a, respectively, and an all-gate on signal AON2 is supplied to the gate line drive circuit 21a, so that the main display panel After refreshing (step S17)
The process is terminated.

On the other hand, if the driver IC 40 determines in step S13 that the driving mode of the liquid crystal display device 100 is not the driving mode for displaying only the sub display panel (step S13: No), only the main display panel is displayed. Therefore, it is determined whether or not the sub display panel is to be refreshed (step S14).
), When it is determined that it is not necessary (step S14: No), the process is terminated. If the driver IC 40 determines that the sub display panel needs to be refreshed (step S14: Yes), the driver IC 40 refreshes all the source lines 32b and the counter electrode 8b of the liquid crystal display panel 30 as the sub display panel. Source signal and drive signal VCOM for performing
And the gate line drive circuit 21b is supplied with the entire gate-on signal AON1 to refresh the sub display panel (step S15), and then the process is terminated.

As described above, the liquid crystal display device 100 according to the present embodiment is a vertical display in one frame period in the drive mode for displaying either the sub display panel or the main display panel. A period other than the blanking period can be used for driving the display panel that performs display out of the main display panel or the sub display panel, and a gate signal for driving the display panel that performs display, Each drive frequency of the source signal and the clock signal can be reduced to the maximum.

[Modification]
The present invention can be variously modified without departing from the spirit of the present invention. For example, in the above-described embodiment, the gate line driving circuit and the source line driving circuit of the main display panel and the sub display panel are shown separately, but the present invention is not limited to this, and instead, the driver I
Needless to say, C may have all the drive circuits for the main display panel and the sub display panel.

Further, in the above-described embodiment, a two-screen display liquid crystal display device having a separated main display panel and sub display panel is shown. However, the present invention is not limited to this, and instead in a single-screen liquid crystal display device. Needless to say, the present invention can also be applied to the case of so-called partial driving in which the screen is driven by being divided into a display area and a non-display area.

[Electronics]
Next, with reference to FIGS. 7 and 8, an embodiment of an electronic apparatus including the liquid crystal display device 100 will be described.

Here, the control means 1100 of the drive circuit of the liquid crystal display panels 20 and 30 will be described. FIG. 7 is a block diagram showing the control means 1100 in the liquid crystal display panels 20 and 30. The control means 1100 is controlled by a central control unit 1000 composed of a microcomputer or the like installed in an electronic device on which the liquid crystal display panels 20 and 30 are mounted. The drive circuit 110D corresponds to the gate line drive circuit in the liquid crystal display panels 20 and 30 described above, the source line drive circuit in the driver IC 40, and the counter electrode drive circuit. Control means 1100
Includes a display information output source 1110, a display processing circuit 1120, a power supply circuit 1130, and a timing generator 1140.

The display information output source 1110 is a ROM (Read Only Memory) or a RAM (Random Access Me).
mory), a storage unit composed of a magnetic recording disk, an optical recording disk, and the like, and a tuning circuit that tunes and outputs a digital image signal. Based on various clock signals generated by the timing generator 1140, The display information is supplied to the display information processing circuit 1120 in the form of a predetermined format image signal or the like.

The display information processing circuit 1120 includes various known circuits such as a serial-parallel conversion circuit, an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit, and executes processing of input display information to obtain image information. Are supplied to the driver circuit together with the clock signal as a source signal and a gate signal. The power supply circuit 1130 supplies a predetermined voltage to each component described above. The display information processing circuit 1120 corresponds to a control circuit in the driver IC 40.

Next, a specific example of an electronic apparatus to which the liquid crystal display device 100 according to this embodiment can be applied will be described with reference to FIG.

FIG. 8 shows a mobile phone 2000 which is an embodiment of an electronic apparatus according to the present invention. The cellular phone 2000 includes a main body 2001 having various operation buttons and a built-in microphone, and a display unit 2002 having a display screen and an antenna and a built-in speaker. The main body 2001 and the display 2002 are mutually connected. It is configured to be foldable. The display unit 100 incorporates the above-described display device 100. The display screen 110 of the main-side liquid crystal display panel 20 is configured to be visible on the inner surface, and the sub-side liquid crystal display panel is disposed on the outer surface. 30 display screens 130 are configured to be visible.

In the present embodiment, as shown in FIG. 8A, by opening the display unit 2002 from the main body unit 2001, the liquid crystal display panel 20 on the main side in response to a command from the central control unit 1000.
Lights up and a predetermined image is displayed. Further, as shown in FIG. 8B, by folding the display unit 2002 onto the main body unit 2001, the liquid crystal display panel 20 on the main side is turned off, and instead, the liquid crystal display panel 30 on the sub side is turned on. It can also be configured to display an image.

It is a side view which shows the structure of the liquid crystal display device which concerns on this embodiment. It is a top view of the liquid crystal display panel which concerns on this embodiment. It is a drive sequence figure in 2 screen display. It is a drive sequence figure in the case of displaying only a sub display panel. It is a drive sequence diagram in the case of displaying only the main display panel. 4 is a flowchart illustrating a driving method of the liquid crystal display device according to the embodiment. It is a figure which shows the circuit structure of the electronic device to which the liquid crystal display device of this embodiment is applied. It is a figure which shows the example of the electronic device to which the liquid crystal display device of this embodiment is applied.

Explanation of symbols

32a, 32b source line, 33a, 33b gate line, 21a, 21b gate line drive circuit, 40 driver IC, 20, 30 liquid crystal display panel, 100 liquid crystal display device

Claims (4)

A display unit comprising a plurality of display areas, a plurality of signal lines common to the plurality of display areas, and a plurality of scanning lines provided in each of the plurality of display areas;
A scanning line driving circuit for supplying a scanning signal to the plurality of scanning lines for each of the plurality of display areas;
A signal line driving circuit for supplying signals to the plurality of signal lines;
A control unit for controlling the scanning line driving circuit and the signal line driving circuit,
When the first display area is set to the display state and the second display area is set to the non-display state among the plurality of display areas, the control unit displays the first display area during one frame period. In the display period, a scanning signal is sequentially supplied to the plurality of scanning lines in the first display region while the signal is supplied to the plurality of signal lines, and the second display region is set to a non-display state. In the non-display period, a predetermined voltage is simultaneously supplied to all of the plurality of signal lines, and a scanning signal is simultaneously supplied to all of the plurality of scanning lines in the second display region. Electro-optic device. The electro-optical device according to claim 1, wherein the non-display period is a vertical blanking period, and the display period is a period other than the vertical blanking period in the one frame period.   An electronic apparatus comprising the liquid crystal display device according to claim 1 in a display unit. A display unit comprising a plurality of display areas, a plurality of signal lines common to the plurality of display areas, and a plurality of scanning lines provided in each of the plurality of display areas;
A scanning line driving circuit for supplying a scanning signal to the plurality of scanning lines for each of the plurality of display areas;
A signal line driving circuit for supplying signals to the plurality of signal lines;
A control unit that controls the scanning line driving circuit and the signal line driving circuit, and a driving method of an electro-optical device,
When the first display area is set to the display state and the second display area is set to the non-display state among the plurality of display areas, the control unit displays the first display area during one frame period. In the display period, a scanning signal is sequentially supplied to the plurality of scanning lines in the first display region while the signal is supplied to the plurality of signal lines, and the second display region is set to a non-display state. In the non-display period, driving of the electro-optical device that supplies a predetermined voltage to all of the plurality of signal lines all at once and supplies a scanning signal to all the plurality of scanning lines in the second display area at the same time Method.

Images