CN107505782B

CN107505782B - Array substrate, liquid crystal display device and driving method

Info

Publication number: CN107505782B
Application number: CN201710787179.3A
Authority: CN
Inventors: 乔艳冰; 赵哲; 朱欢欢
Original assignee: InfoVision Optoelectronics Kunshan Co Ltd
Current assignee: InfoVision Optoelectronics Kunshan Co Ltd
Priority date: 2017-09-04
Filing date: 2017-09-04
Publication date: 2021-01-15
Anticipated expiration: 2037-09-04
Also published as: CN107505782A

Abstract

The invention discloses an array substrate, a liquid crystal display device and a driving method, wherein the array substrate is provided with a plurality of scanning lines, a plurality of data lines and a plurality of pixel units which are arranged in an array, the array substrate is also provided with a first voltage line, a second voltage line, a plurality of common electrode strips and a plurality of control switches, each common electrode strip extends along the scanning line direction, the plurality of common electrode bars include a plurality of first common electrode bars and a plurality of second common electrode bars, the plurality of first common electrode bars and the plurality of second common electrode bars are disposed at intervals from each other in a data line direction, the plurality of control switches include a plurality of first control switches and a plurality of second control switches, each of the first common electrode bars is connected to the first voltage line and a corresponding one of the scanning lines through one of the first control switches, and each of the second common electrode bars is connected to the second voltage line and a corresponding one of the scanning lines through one of the second control switches.

Description

Array substrate, liquid crystal display device and driving method

Technical Field

The invention relates to the technical field of liquid crystal display, in particular to an array substrate, a liquid crystal display device and a driving method.

Background

A Liquid Crystal Display (LCD) has advantages of good picture quality, small size, light weight, low driving voltage, low power consumption, no radiation, and relatively low manufacturing cost, and is dominant in the field of flat panel displays.

With the continuous progress of the liquid crystal display technology, the viewing angle of the display has been widened from about 120 ° to over 160 °, and people want to effectively protect business confidentiality and personal privacy while enjoying visual experience brought by a large viewing angle, so as to avoid business loss or embarrassment caused by the leakage of screen information. There is therefore a need for a display device that can be switched to a narrow viewing angle in addition to a wide viewing angle.

At present, the switching between the wide viewing angle and the narrow viewing angle is generally realized by the shielding function of the shutter, which requires an additional shielding film outside the display device, and is inconvenient to use.

Recently, it has been proposed to apply a vertical electric field to liquid crystal molecules by using a viewing angle control electrode on the color filter substrate (CF) side to switch between a wide viewing angle and a narrow viewing angle. Referring to fig. 1 and 2, the lcd device includes an upper substrate 11, a lower substrate 12, and a liquid crystal layer 13 disposed between the upper substrate 11 and the lower substrate 12, wherein the upper substrate 11 is provided with a viewing angle control electrode 111, and the lower substrate 12 is provided with a common electrode 121 and a pixel electrode 122. As shown in fig. 1, in the wide viewing angle display, the viewing angle control electrode 111 of the upper substrate 11 does not apply a voltage, and the liquid crystal display device realizes the wide viewing angle display. As shown in fig. 2, when a narrow viewing angle display is required, the viewing angle control electrode 111 of the upper substrate 11 applies a large voltage, the liquid crystal molecules in the liquid crystal layer 13 tilt due to the vertical electric field E (as shown by the arrow in the figure), and the contrast of the liquid crystal display device is reduced due to light leakage, thereby finally realizing a narrow viewing angle.

In order to prevent polarization of liquid crystal molecules, the voltage applied to the viewing angle control electrode 111 is generally an ac voltage in narrow viewing angle display. The viewing angle control electrode 111 is a planar electrode on the whole surface, that is, the viewing angle control electrode 111 covers all the pixel units on the whole surface, for the liquid crystal display device, only one row of pixel units is charged at each moment, the rest uncharged pixel units are in a suspended state for holding charges, the voltage change on the viewing angle control electrode 111 can change the voltage of the pixel electrode in the suspended state through capacitive coupling, and the voltage difference between the pixel electrode 122 and the common electrode 121 and the viewing angle control electrode 111 respectively changes, so that the arrangement state of liquid crystal molecules is changed, that is, the transmittance of the pixel unit in which the capacitive coupling occurs is correspondingly changed. In addition, as shown in fig. 3, in order to realize the polarity inversion display, the polarities of the data voltages (Vdata) applied to the two adjacent pixel cells P1 and P2 are different, but in the narrow viewing angle display, since the viewing angle control electrode 111 is a planar electrode of the whole surface, the voltage difference between the pixel electrode 122 and the viewing angle control electrode 111 of the two adjacent pixel cells is different at the same time, so that the vertical electric field voltage difference generated by the two adjacent pixel cells P1 and P2 with different polarities is different, which easily causes the brightness of the two adjacent pixel cells P1 and P2 to be different, and as shown in fig. 4, the pixel cell on the left side is darker than the pixel cell on the right side. Therefore, at the same time, the difference of the transmittance of the pixel units at different positions can cause uneven brightness of the display panel; at different times, the display panel flickers due to the difference of the penetration rates of the same pixel unit, and the image quality of the panel is reduced due to the superposition of the difference of the penetration rates in space and time, so that the display panel is prone to display unevenness, flickers and other problems.

In order to solve this problem, the prior art optimizes the driving waveform and driving voltage of the ac voltage applied to the viewing angle control electrode 111 to reduce the influence of the display unevenness, but the effect of improving the image quality is limited; alternatively, the flicker of the picture is reduced by doubling the frame frequency of the liquid crystal display device (i.e., increasing the frame frequency from 60Hz to 120Hz), but this increases the logic power consumption, and the time for turning on each scan line is halved, which reduces the pixel charging time and affects the pixel charging effect.

Disclosure of Invention

The invention aims to provide an array substrate, a liquid crystal display device and a driving method, which can realize wide and narrow visual angle switching in different occasions and solve the problems of uneven picture display and flicker.

The embodiment of the invention provides an array substrate, which is provided with a plurality of scanning lines, a plurality of data lines and a plurality of pixel units arranged in an array, it is characterized in that the array substrate is also provided with a first voltage wire, a second voltage wire, a plurality of common electrode strips and a plurality of control switches, each common electrode strip extends along the direction of the scanning line, the plurality of common electrode bars include a plurality of first common electrode bars and a plurality of second common electrode bars, the plurality of first common electrode bars and the plurality of second common electrode bars are disposed at intervals from each other in a data line direction, the plurality of control switches include a plurality of first control switches and a plurality of second control switches, each of the first common electrode bars is connected to the first voltage line and a corresponding one of the scanning lines through one of the first control switches, and each of the second common electrode bars is connected to the second voltage line and a corresponding one of the scanning lines through one of the second control switches.

The embodiment of the invention also provides a liquid crystal display device, which comprises an array substrate, a color film substrate arranged opposite to the array substrate and a liquid crystal layer positioned between the array substrate and the color film substrate, wherein the array substrate is the array substrate, and the color film substrate is provided with an upper electrode on the whole surface.

An embodiment of the present invention further provides a driving method for driving the liquid crystal display device, including:

in a first viewing angle mode, applying a reference voltage to the upper electrode, applying a first common voltage having a smaller magnitude than the reference voltage to each first common electrode bar through the first voltage lines and the first control switches, and applying a second common voltage having a smaller magnitude than the reference voltage to each second common electrode bar through the second voltage lines and the second control switches, so that voltage differences between all the common electrode bars and the upper electrode are smaller than a first preset value;

in a second viewing angle mode, applying a reference voltage to the upper electrode, applying a first common voltage having a larger magnitude than the reference voltage to each first common electrode bar through the first voltage lines and the first control switches, and applying a second common voltage having a larger magnitude than the reference voltage to each second common electrode bar through the second voltage lines and the second control switches, so that voltage differences between all the common electrode bars and the upper electrode are larger than a second preset value; wherein the second preset value is greater than or equal to the first preset value.

The array substrate, the liquid crystal display device and the driving method provided by the embodiment of the invention are realized by switching the voltage for controlling the switching of the wide and narrow visual angles from the visual angle control electrode on the color film substrate side to the common electrode strip on the array substrate side, the common electrode on the array substrate is divided into a plurality of mutually independent common electrode strips, each common electrode strip is correspondingly connected with one scanning line through one control switch, whether the common electrode strip is opened or not is controlled through the control switch, when each row of scanning lines is opened, the control switch connected with the scanning line is also opened simultaneously, each row of pixel units and the common electrode strip covering the row of pixel units are charged, the common electrode strips are independently endowed with voltage signals during pixel scanning, the charged common electrode strips of each row are not influenced with the common electrode strips to be charged, and the voltage signals endowed by each row of common electrode strips are not influenced by the charging of the adjacent row of common electrode strips, therefore, the problems of display unevenness and flicker in the display panel caused by the coupling effect are solved, and the display image quality is improved.

Drawings

Fig. 1 is a partial cross-sectional view of a conventional liquid crystal display device at a wide viewing angle.

Fig. 2 is a partial cross-sectional view of the liquid crystal display device of fig. 1 at a narrow viewing angle.

Fig. 3 is a voltage diagram of two pixel units of the liquid crystal display device in fig. 1 under a narrow viewing angle.

Fig. 4 is a diagram illustrating display effects of two pixel units of the liquid crystal display device in fig. 1 under a narrow viewing angle.

Fig. 5 is a schematic circuit diagram of a liquid crystal display device according to a first embodiment of the invention.

Fig. 6 is a schematic plan view of the common electrode bar on the liquid crystal display device of fig. 5.

Fig. 7 is a schematic partial cross-sectional view of the liquid crystal display device of fig. 5 taken along line VII-VII.

Fig. 8 is a schematic view of the liquid crystal display device in fig. 7 at a narrow viewing angle.

Fig. 9 is a schematic diagram of driving waveforms of the liquid crystal display device in fig. 7 at a narrow viewing angle.

Fig. 10 is a voltage diagram of two pixel units of the liquid crystal display device in fig. 7 under a narrow viewing angle.

Fig. 11 is a diagram of display effects of two pixel units of the liquid crystal display device in fig. 7 under a narrow viewing angle.

Fig. 12a and 12b are schematic plan views of the lcd device of fig. 7.

Fig. 13 is a schematic circuit diagram of a liquid crystal display device according to a second embodiment of the invention.

Fig. 14 is a schematic circuit diagram of a liquid crystal display device according to a third embodiment of the invention.

Fig. 15 is a schematic circuit diagram of a liquid crystal display device according to a fourth embodiment of the invention.

Fig. 16 is a schematic circuit diagram of a liquid crystal display device according to a fifth embodiment of the invention.

Fig. 17 is a schematic circuit diagram of a liquid crystal display device according to a sixth embodiment of the invention.

Fig. 18 is a schematic plan view illustrating a structure of a common electrode bar on the liquid crystal display device of fig. 17.

FIG. 19 is a partial cross-sectional view of a liquid crystal display device in a seventh embodiment of the present invention.

Fig. 20 is a schematic view of the liquid crystal display device in fig. 19 at a wide viewing angle.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description of the embodiments, structures, features and effects of the present invention will be made with reference to the accompanying drawings and examples.

[ first embodiment ]

Referring to fig. 5 to 7, a liquid crystal display device according to a first embodiment of the invention includes a display panel 50, where the display panel 50 includes an array substrate 20, a color filter substrate 30 disposed opposite to the array substrate 20, and a liquid crystal layer 40 disposed between the array substrate 20 and the color filter substrate 30.

The array substrate 20 is provided with a plurality of scan lines 21 and a plurality of data lines 22. The plurality of scanning lines 21 and the plurality of data lines 22 are insulated and crossed to define a plurality of pixel units arranged in an array. Each pixel unit is provided with a pixel electrode 23 and a thin film transistor 26, and the pixel electrode 23 is connected to the scanning line 21 and the data line 22 adjacent to the thin film transistor 26 through the thin film transistor 26. Specifically, the thin film transistor 26 includes a gate electrode, a source electrode and a drain electrode, wherein the gate electrode is electrically connected to the corresponding scan line 21, the gate electrode may be independently disposed or may be a part of the scan line 21, the source electrode is electrically connected to the corresponding data line 22, and the drain electrode is electrically connected to the corresponding pixel electrode 23.

The array substrate 20 is further provided with a plurality of common electrode strips 24 arranged in parallel at intervals, each common electrode strip 24 extends along the direction of the scanning line 21, and in this embodiment, each common electrode strip 24 correspondingly covers a whole row of pixel units. The plurality of common electrode bars 24 include a plurality of first common electrode bars 24a and a plurality of second common electrode bars 24b, and the plurality of first common electrode bars 24a and the plurality of second common electrode bars 24b are disposed to be spaced apart from each other in the direction of the data line 22. In the embodiment, in the direction of the data line 22, each of the first common electrode stripes 24a and each of the second common electrode stripes 24b are alternately disposed, wherein the plurality of first common electrode stripes 24a correspondingly cover the pixel cells in the odd-numbered rows (i.e., rows 1, 3, 5, …), and the plurality of second common electrode stripes 24b correspondingly cover the pixel cells in the even-numbered rows (i.e., rows 2, 4, 6, …).

As shown in fig. 7, on the array substrate 20, the pixel electrode 23 and the common electrode bar 24 may be located at different layers with an insulating layer 29 interposed therebetween, and the pixel electrode 23 may be located above the common electrode bar 24, so that the liquid crystal display device forms a Fringe Field Switching (FFS) structure. In the liquid crystal display device, during normal display, a fringe electric field is generated between the common electrode stripes 24 and the pixel electrodes 23, so that liquid crystal molecules rotate in a plane substantially parallel to the substrate to obtain a wide viewing angle.

The color filter substrate 30 is provided with a color resist layer 31, a Black Matrix (BM)32, and an upper electrode 33. The color resist layer 31 is, for example, R, G, B color resist. The upper electrode 33 is a planar electrode over the entire surface, i.e., the entire surface of the upper electrode 33 covers the display region. The color resist layer 31 and the black matrix 32 are disposed on the surface of the color filter substrate 30 facing the liquid crystal layer 40, and other film structures are disposed on the color resist layer 31 and the black matrix 32. At least one insulating layer or planarization layer may be further disposed on the color filter substrate 30. In this embodiment, a planarization layer 35 is further disposed on the color filter substrate 30, the planarization layer 35 covers the color resist layer 32 and the black matrix 31, and the upper electrode 33 is formed on the planarization layer 35.

As shown in fig. 5, the array substrate 20 is further provided with a first voltage line 201, a second voltage line 202 and a plurality of control switches 25, the plurality of control switches 25 include a plurality of first control switches 25a and a plurality of second control switches 25b, each first common electrode bar 24a is connected to the first voltage line 201 and a corresponding scanning line 21 through one first control switch 25a, and each second common electrode bar 24b is connected to the second voltage line 202 and a corresponding scanning line 21 through one second control switch 25 b. The first voltage line 201, the second voltage line 202, and the plurality of

control switches

25a, 25b are disposed in the non-display area of the display panel 50. In this embodiment, the first voltage line 201, the second voltage line 202, and the plurality of

control switches

25a and 25b are disposed on the same side of the display panel 50.

Each of the

control switches

25a, 25b includes a control end, a first path end and a second path end, the control end of each of the first control switches 25a is connected to the corresponding scan line 21, the first path end of each of the first control switches 25a is connected to the first voltage line 201, the second path end of each of the first control switches 25a is connected to the corresponding first common electrode bar 24a, the control end of each of the second control switches 25b is connected to the corresponding scan line 21, the first path end of each of the second control switches 25b is connected to the second voltage line 202, and the second path end of each of the second control switches 25b is connected to the corresponding second common electrode bar 24 b. The control switches 25a and 25b may be thin film transistors, the control terminal is a gate, one of the first and second via terminals is a source, and the other is a drain.

In this embodiment, each pixel unit in each row is respectively connected to two scanning lines 21 on the upper and lower sides of the pixel unit in the row, and the common electrode strip 24 in each row is connected to the scanning line 21 on the upper side or the lower side of the pixel unit in the row through the corresponding control switch 25. In this embodiment, the common electrode bar 24 of each row is connected to the scan line 21 on the lower side of the pixel units of the row through the corresponding control switch 25, as shown in fig. 5, but not limited thereto, in other embodiments, the common electrode bar 24 of each row may also be connected to the scan line 21 on the upper side of the pixel units of the row through the corresponding control switch 25 (not shown).

In this embodiment, each pixel unit in each row is alternately connected to two scan lines 21 located at the upper and lower sides of the pixel unit in the row, and each pixel unit in each column is alternately connected to two data lines 22 located at the left and right sides of the pixel unit in the column. For example, for the first row of pixel cells, each pixel cell at the odd number position is connected to the scan line Gate0 at the upper side, and each pixel cell at the even number position is connected to the scan line Gate1 at the lower side; for the second row of pixel units, each pixel unit at the odd number position is connected with the scanning line Gate1 at the upper side, and each pixel unit at the even number position is connected with the scanning line Gate2 at the lower side; the above arrangement is repeated every two subsequent rows. For the pixel units in the first column, the pixel units in the odd number are connected with the Data line Data1 on the left side, and the pixel units in the even number are connected with the Data line Data2 on the right side; for the second column of pixel units, each pixel unit at the odd number position is connected with the Data line Data3 at the right side, and each pixel unit at the even number position is connected with the Data line Data2 at the left side; the above arrangement is repeated every two subsequent columns.

Also, the respective pixel cells in each row are charged through only the data lines 22 of the odd-numbered columns or only the even-numbered columns. For example, each pixel cell in the first row is connected to only the odd-numbered Data line 22(Data1, Data3, Data5, etc.), so each pixel cell in the first row is charged only through the Data line 22 of the odd-numbered column, and the pixel cells in the remaining odd-numbered rows are also charged only through the Data line 22 of the odd-numbered column; each pixel cell in the second row is connected to only the Data line 22 of the even bit (Data2, Data4, Data6, etc.), so each pixel cell in the second row is charged only through the Data line 22 of the even column, and the pixel cells in the remaining even rows are also charged only through the Data line 22 of the even column. In this way, the polarity of the Data voltage (Vdata) applied to each Data line 22 can be maintained in the same frame, and for example, in the same frame, the Data1 applies the Data voltage (Vdata-) of negative polarity and the Data2 applies the Data voltage (Vdata +), thereby realizing row inversion display by driving the Data lines and columns, and saving power consumption.

In a frame of picture, when all the scanning lines 21 are sequentially turned on to charge the pixel units in each row, because each first common electrode bar 24a is connected with the first voltage line 201 through one first control switch 25a, each first common electrode bar 24a is charged with the first common voltage in the charging time period of the pixel units in the row covered correspondingly; since each of the second common electrode bars 24b is connected to the second voltage line 202 through one of the second control switches 25b, each of the second common electrode bars 24b will be charged with the second common voltage during the charging period of the pixel cells of the corresponding covered row.

For example, when the scan lines Gate0 and Gate1 are sequentially turned on to charge the pixel cells in the first row, the first control switch 25a connected to the scan line Gate1 is also turned on, and the first voltage line 201 charges the first common electrode bar 24a covering the pixel cells in the first row through the turned-on first control switch 25a and charges the first common voltage. When the scan line Gate1 is turned off, the first control switch 25a connected to the scan line Gate1 is also turned off, and the first common voltage charged in the first common electrode bar 24a of the first row is in a charge holding state until the scan line Gate1 of the next frame is turned on again. When the scan lines Gate1 and Gate2 are sequentially turned on to charge the pixel cells in the second row, the second control switch 25b connected to the scan line Gate2 is also turned on, and the second voltage line 202 charges the second common electrode bar 24b covering the pixel cells in the second row through the turned-on second control switch 25b and charges the second common voltage. When the scan line Gate2 is turned off, the second control switch 25b connected to the scan line Gate2 is also turned off, and the second common voltage charged in the second common electrode bar 24b of the second row is in the charge holding state until the scan line Gate2 of the next frame is turned on again.

In this embodiment, the liquid crystal molecules in the liquid crystal layer 40 are positive liquid crystal molecules, and the positive liquid crystal molecules have the advantage of fast response. As shown in fig. 7, in an initial state (i.e., a state where no voltage is applied to the liquid crystal display device), the positive liquid crystal molecules in the liquid crystal layer 40 assume a lying posture substantially parallel to the

substrates

20, 30, i.e., a long axis direction of the positive liquid crystal molecules is substantially parallel to the surfaces of the

substrates

20, 30. In practical applications, however, the positive liquid crystal molecules in the liquid crystal layer 40 and the

substrates

20 and 30 may have a small initial pretilt angle, which may range from 10 degrees or less, that is: 0 DEG ≦ theta ≦ 10 deg.

In this embodiment, the liquid crystal display device can be switched between the wide viewing angle mode and the narrow viewing angle mode by controlling the voltage signals applied to the upper electrode 33 of the color film substrate 30 and the common electrode stripes 24 of the array substrate 20.

Wide view angle mode: referring to fig. 5 and 7, in the embodiment, in the wide viewing angle mode, a reference voltage is applied to the upper electrode 33 of the color filter substrate 30, a first common voltage having a smaller amplitude than the reference voltage is applied to each first common electrode stripe 24a on the array substrate 20 through the first voltage line 201 and the first control switch 25a, and a second common voltage having a smaller amplitude than the reference voltage is applied to each second common electrode stripe 24b on the array substrate 20 through the second voltage line 202 and the second control switch 25b, so that voltage differences between all the common electrode stripes 24 and the upper electrode 33 are smaller than a first preset value (for example, smaller than 1V). At this time, since the voltage difference between all the common electrode bars 24 and the upper electrodes 33 is small, the tilt angle of the liquid crystal molecules in the liquid crystal layer 40 hardly changes, and the liquid crystal display device still maintains the lying posture, so that the liquid crystal display device realizes normal wide viewing angle display.

Specifically, in the wide viewing angle mode, the reference voltage applied to the upper electrode 33 may be a constant 0V, and the voltages applied to the first voltage line 201 and the second voltage line 202 may also be a constant 0V, so that the first common voltage applied to each first common electrode bar 24a and the second common voltage applied to each second common electrode bar 24b are both the same as the reference voltage, that is, both are 0V, so that the voltage difference between each common electrode bar 24 and the upper electrode 33 is zero, and a good wide viewing angle effect can be achieved. However, the present embodiment is not limited thereto, and in the wide viewing angle mode, the voltages applied on the first and

second voltage lines

201 and 202 may be a direct current voltage or an alternating current voltage other than 0V as long as the voltage difference between each first common electrode bar 24a and the upper electrode 33 and the voltage difference between each second common electrode bar 24b and the upper electrode 33 are made smaller than the first preset value.

Narrow view angle mode: referring to fig. 5 and 8, in the embodiment, in the narrow viewing angle mode, a reference voltage is applied to the upper electrode 33 of the color filter substrate 30, a first common voltage having a larger amplitude than the reference voltage is applied to each first common electrode stripe 24a on the array substrate 20 through the first voltage line 201 and the first control switch 25a, and a second common voltage having a larger amplitude than the reference voltage is applied to each second common electrode stripe 24b on the array substrate 20 through the second voltage line 202 and the second control switch 25b, so that voltage differences between all the common electrode stripes 24 and the upper electrode 33 are greater than a second preset value (for example, greater than 2V), where the second preset value is greater than or equal to the first preset value. At this time, since the voltage difference between all the common electrode stripes 24 and the upper electrodes 33 is large, a strong vertical electric field E (as shown by arrows in fig. 8) is generated between the array substrate 20 and the color film substrate 30 in the liquid crystal cell, and the positive liquid crystal molecules rotate in a direction parallel to the electric field lines under the action of the electric field, so that the positive liquid crystal molecules are deflected under the action of the vertical electric field E, the tilt angle between the liquid crystal molecules and the

substrates

20 and 30 is increased and tilted, the liquid crystal molecules are changed from the lying posture to the inclined posture, the liquid crystal display device generates large-angle observation light leakage, the contrast is reduced and the viewing angle is narrowed in the oblique viewing direction, and the liquid crystal display device finally realizes narrow viewing angle display.

Referring to fig. 5 and 9, in the narrow viewing angle mode, the reference voltage applied by the top electrode 33 may be a constant 0V, the first ac control voltage V1 is applied to the first voltage line 201, and the second ac control voltage V2 is applied to the second voltage line 202. In fig. 9, Gate (2N-1) represents the odd-numbered scan lines 21, Gate (2N) represents the even-numbered scan lines 21, V1 represents the first ac control voltage applied to the first voltage line 201, V2 represents the second ac control voltage applied to the second voltage line 202, Vcom1_ (2N-1) represents the first common voltage waveform charged to each first common electrode bar 24a, and Vcom2_ (2N) represents the second common voltage waveform charged to each second common electrode bar 24 b.

As shown in fig. 9, in the present embodiment, the first ac control voltage V1 and the second ac control voltage V2 are in a complementary relationship with opposite phases, wherein the low potential is Vcom + and the high potential is Vcom +. When the scan signals are applied to the scan lines 21, the first control switches 25a output a first common voltage to the first common electrode stripes 24a, and the second control switches 25b output a second common voltage to the second common electrode stripes 24b, respectively, with the polarities of the first common voltage and the second common voltage being opposite. For example, in the nth frame, the polarity of the first common voltage charged into each first common electrode bar 24a is Vcom +, and the polarity of the first common voltage charged into each second common electrode bar 24b is Vcom +, which are opposite.

Also, the polarities of the first ac control voltage V1 and the second ac control voltage V2 are inverted every frame between Vcom-and Vcom +. Therefore, in the (N + 1) th frame, the charged first common voltage of each first common electrode stripe 24a is converted into Vcom +, and the charged first common voltage of each second common electrode stripe 24b is converted into Vcom-, with opposite polarities. And repeating the process of the N frame picture again by the N +2 frame picture, and circulating the process.

Specifically, in the narrow viewing angle mode, the magnitudes of the first common voltage applied to each first common electrode bar 24a and the second common voltage applied to each second common electrode bar 24b can be selected to be greater than 3V (i.e., | Vcom- | ≧ 3V, | Vcom + | ≧ 3V), e.g., Vcom-equal to-3.6V, Vcom + equal to +3.6V, so that the voltage difference between each common electrode bar 24 and the upper electrode 33 is greater than 3V, and a good narrow viewing angle effect can be achieved.

As shown in fig. 5 and 9, the liquid crystal display device adopts row inversion (row inversion) during displaying, and the polarity of the data voltage applied to the pixel cells in a row covered by each first common electrode bar 24a is the same as the polarity of the first common voltage charged on the first common electrode bar 24a, and the polarity of the data voltage charged to the pixel cells in a row covered by each second common electrode bar 24b is the same as the polarity of the second common voltage charged on the second common electrode bar 24 b. Specifically, in the nth frame, when the first common electrode bar 24a is charged with the first common voltage Vcom-, which is a negative polarity, the data line 22 is used to apply the data voltage with the negative polarity to the pixel units in the odd-numbered rows, and when the second common electrode bar 24b is charged with the second common voltage Vcom +, which is a positive polarity, the data line 22 is used to apply the data voltage with the positive polarity to the pixel units in the even-numbered rows; in the (N + 1) th frame, when the positive first common voltage Vcom + is charged in each of the first common electrode stripes 24a, the positive data voltage is also applied to the pixel cells in the odd-numbered rows through the data lines 22, and when the negative second common voltage Vcom-is charged in each of the second common electrode stripes 24b, the negative data voltage is also applied to the pixel cells in the even-numbered rows through the data lines 22. And repeating the process of the N frame picture again by the N +2 frame picture, and circulating the process.

As shown in fig. 10, in the present embodiment, each common electrode bar 24 arranged along the row direction is displayed by using row inversion, and the polarity of the common voltage applied to each common electrode bar 24 is the same as the polarity of the data voltage applied to the pixel unit in the row correspondingly covered by the common electrode bar 24, so that the voltage difference between the pixel electrode 23 and the common electrode bar 24 in two adjacent pixel units with different polarities is the same in the upper and lower rows, thereby improving the problem of inconsistent brightness between the two adjacent pixel units. As shown in fig. 11, the display brightness of two adjacent pixel units with different polarities is relatively uniform.

As shown in fig. 7 and 8, the liquid crystal display device further includes a driving circuit 60, and the driving circuit 60 applies required voltage signals to the upper electrode 33 of the color filter substrate 30 and the common electrode stripes 24 of the array substrate 20, respectively. In order to apply voltage signals to the upper electrodes 33 of the color filter substrate 30, the array substrate 20 may be conducted to the color filter substrate 30 through the conductive adhesive 70 in the peripheral non-display region of the display panel 50, the driving circuit 60 provides the voltage signals to the array substrate 20, and the array substrate 20 applies the voltage signals to the upper electrodes 33 of the color filter substrate 30 through the conductive adhesive 70.

As shown in fig. 12a and 12b, the liquid crystal display device is further provided with a viewing angle switching key 80 for switching different viewing angle modes of the liquid crystal display device. The view angle switching key 80 may be a mechanical key (as shown in fig. 12a) or a virtual key (as shown in fig. 12b, set by software control or application program). When a user needs to switch the wide and narrow viewing angles, a viewing angle switching request can be sent to the liquid crystal display device by operating the viewing angle switching key 80, and finally the driving circuit 60 controls voltage signals applied to the upper electrode 33 of the color film substrate 30 and the common electrode strips 24 of the array substrate 20 to realize the switching of the wide and narrow viewing angles, so that the user can freely select and switch the wide and narrow viewing angles according to different peep-proof requirements.

In this embodiment, the voltage for controlling the switching of the wide and narrow viewing angles is switched from the viewing angle control electrode on the color film substrate side to the common electrode strip 24 on the array substrate side, the common electrode on the array substrate 20 is divided into a plurality of mutually independent common electrode strips 24, each common electrode strip 24 is correspondingly connected with one scanning line 21 through one

control switch

25a, 25b, whether the common electrode strip 24 is opened or not is controlled through the

control switches

25a, 25b, when each row of scanning lines 21 is opened, the

control switches

25a, 25b connected with the scanning line 21 are also simultaneously opened, each row of pixel units and the common electrode strip 24 covering the row of pixel units are charged, so that the common electrode strips 24 are independently given voltage signals during pixel scanning, and the charged common electrode strips 24 and the common electrode strips 24 to be charged do not affect each other, the voltage signal given to each row of the common electrode strips 24 is not influenced by the charging of the adjacent row of the common electrode strips 24, so that the problems of display unevenness and flicker in the display panel caused by the coupling effect are solved, and the display image quality is improved.

In this embodiment, the polarity of the first common voltage charged in each first common electrode bar 24a is opposite to the polarity of the second common voltage charged in each second common electrode bar 24b, and the polarity of the common voltage applied to each common electrode bar 24 is the same as the polarity of the data voltage (Vdata) applied to the pixel unit in the row covered by the common electrode bar 24, so that when the row inversion is used in combination for displaying, the voltage difference between the pixel electrode 23 and the common electrode bar 24 in two adjacent pixel units with different polarities can be the same, thereby improving the problem of inconsistent brightness of the two adjacent pixel units.

[ second embodiment ]

Referring to fig. 13, the difference between the liquid crystal display device provided in this embodiment and the first embodiment is that, in this embodiment, the plurality of first common electrode bars 24a and the plurality of second common electrode bars 24b are disposed at intervals in the direction of the data line 22: in the direction of the data line 22, every two first common electrode strips 24a and every two second common electrode strips 24b are alternately arranged, that is, the pixel units in the 1 st and 2 nd rows are covered by the first common electrode strips 24a, the pixel units in the 3 rd and 4 th rows are covered by the second common electrode strips 24b, and so on, and the above arrangement is repeated every four subsequent rows.

Other structures of this embodiment can be seen from the first embodiment, and are not described herein again.

[ third embodiment ]

Referring to fig. 14, the difference between the liquid crystal display device provided in this embodiment and the first embodiment is that, in this embodiment, each pixel unit in each row is connected to the same scan line 21 and controlled by the same scan line 21, and the common electrode bar 24 in each row is connected to the scan line 21 controlling the pixel units in the row through the corresponding control switch 25. For example, each pixel cell in the first row is connected to the scan line Gate0 located at the upper side of the pixel cell in the row, and the common electrode bar 24a located in the first row is connected to the scan line Gate0 controlling the pixel cells in the row through the control switch 25 a; each pixel unit in the second row is connected to the scanning line Gate1 located at the upper side of the pixel unit in the row, and the common electrode bar 24b located in the second row is connected with the scanning line Gate1 for controlling the pixel unit in the row through the control switch 25 b; the connection mode of the pixel units in other rows is similar.

[ fourth embodiment ]

Referring to fig. 15, the liquid crystal display device provided in this embodiment is different from the first embodiment in that in this embodiment, the first voltage line 201 and the plurality of first control switches 25a are disposed on one side of the display panel 50, the second voltage line 202 and the plurality of second control switches 25b are disposed on the opposite side of the display panel 50, for example, the first voltage line 201 and the plurality of first control switches 25a are disposed on the left side of the display panel 50, and the second voltage line 202 and the plurality of second control switches 25b are disposed on the right side of the display panel 50. By disposing the voltage line and the control switch separately, the two side frames of the display panel 50 can be designed more reasonably.

[ fifth embodiment ]

Referring to fig. 16, the difference between the liquid crystal display device provided in this embodiment and the first embodiment is that the common electrode bar 24 in the nth row is connected to the nth-x scanning lines 21 through the corresponding control switches 25, where n is an integer greater than or equal to 1, and n > x, where x may be 1,2, or 3. In the present embodiment, the value of x is taken as 1 for example, that is, the control terminal of each control switch 25 is connected to the scan line of the previous stage, that is, Gn-1 (the control switch 25 of the front row may be controlled by the STV signal). Thus, when the scan line Gn-1 is at a high level, the control switch 25 connected to the scan line Gn-1 is turned on, the common electrode bar 24 in the nth row is charged with the common voltage, and when the scan line Gn-1 is at a low level, the control switch 25 connected to the scan line Gn-1 is turned off, and the charged common voltage of the common electrode bar 24 in the nth row is maintained. Before each pixel unit in the nth row is charged, the Gn-1 scanning line is adopted to control the common electrode strip 24 in the nth row to be charged with the common voltage in advance, so that the coupling influence on the charging voltage of the pixel units in the nth row when the common electrode strip 24 in the nth row is charged with the common voltage after the pixel units in the nth row are charged can be avoided.

That is, the present invention can select to synchronously complete the charging of the common electrode bar 24 of the nth row with the common voltage when the pixel cells of the nth row are charged (as shown in fig. 5 and 13-15), or complete the charging of the common electrode bar 24 of the nth row with the common voltage in advance before the pixel cells of the nth row are charged (as shown in fig. 16), so as to avoid the coupling influence on the charging voltage of the pixel cells of the nth row when the common electrode bar 24 of the nth row is charged with the common voltage after the pixel cells of the nth row are charged.

[ sixth embodiment ]

Referring to fig. 17, the difference between the liquid crystal display device provided in this embodiment and the first embodiment is that, in this embodiment, the first common electrode strip 24a covers the pixel units located at the even-numbered positions in a row correspondingly, and the second common electrode strip 24b covers the pixel units located at the odd-numbered positions in a row correspondingly; alternatively, the first common electrode bar 24a covers the pixel units located at odd bits in one row correspondingly, and the second common electrode bar 24b covers the pixel units located at even bits in one row correspondingly. That is, the pixel cells of an entire row are collectively covered by one first common electrode bar 24a and one second common electrode bar 24 b. For example, for a first row of pixel units, the first common electrode bar 24a corresponds to and covers the pixel units located at even-numbered positions in the first row, and the second common electrode bar 24b corresponds to and covers the pixel units located at odd-numbered positions in the first row; for the second row of pixel units, the first common electrode strip 24a correspondingly covers the pixel units positioned at odd bits in the second row, and the second common electrode strip 24b correspondingly covers the pixel units positioned at even bits in the second row; and so on, repeating the arrangement every two subsequent rows.

Specifically, referring to fig. 18, each first common electrode strip 24a and each second common electrode strip 24b are composed of a plurality of electrode blocks 240 that are spaced from each other in series, two adjacent electrode blocks 240 of each first common electrode strip 24a or each second common electrode strip 24b are spaced by a width of one pixel unit, and each electrode block 240 correspondingly covers one pixel unit.

In this embodiment, the first common electrode bar 24a and the second common electrode bar 24b are charged with the common voltages with opposite polarities, so that the dot inversion driving of the pixel unit can be realized, thereby better improving the display image quality.

[ seventh embodiment ]

Referring to fig. 19 and 20, the difference between the liquid crystal display device of the present embodiment and the first embodiment is that the liquid crystal layer 40 of the present embodiment uses negative liquid crystal molecules. With the technical progress, the performance of the negative liquid crystal is remarkably improved, and the application is more and more extensive. In the present embodiment, as shown in fig. 19, in the initial state (i.e., the liquid crystal display device is not applied with any voltage), the negative liquid crystal molecules in the liquid crystal layer 40 have a large initial pretilt angle with respect to the

substrates

20 and 30, i.e., the negative liquid crystal molecules are in an inclined posture with respect to the

substrates

20 and 30 in the initial state.

Narrow view angle mode: referring to fig. 19, in the narrow viewing angle mode, in the embodiment, a reference voltage is applied to the upper electrode 33 of the color filter substrate 30, a first common voltage having a smaller amplitude than the reference voltage is applied to each first common electrode stripe 24a on the array substrate 20 through the first voltage line 201 and the first control switch 25a, and a second common voltage having a smaller amplitude than the reference voltage is applied to each second common electrode stripe 24b on the array substrate 20 through the second voltage line 202 and the second control switch 25b, so that voltage differences between all the common electrode stripes 24 and the upper electrode 33 are smaller than a first preset value (for example, smaller than 1V). At this time, since the voltage difference between all the common electrode bars 24 and the upper electrodes 33 is small, the tilt angle of the liquid crystal molecules in the liquid crystal layer 40 is almost unchanged and remains in a tilt posture, so that the liquid crystal display device has large-angle viewing light leakage, the contrast ratio is reduced in the oblique viewing direction, and the viewing angle is narrowed, and at this time, the liquid crystal display device realizes narrow viewing angle display.

Specifically, in the narrow viewing angle mode, the reference voltage applied by the upper electrode 33 may be a constant 0V, and the first common voltage applied to each first common electrode bar 24a and the second common voltage applied to each second common electrode bar 24b may both be the same as the reference voltage, that is, both are 0V, so that the voltage difference between each common electrode bar 24 and the upper electrode 33 is zero, and a good narrow viewing angle effect may be achieved.

Wide view angle mode: referring to fig. 20, in the embodiment, in the wide viewing angle mode, a reference voltage is applied to the upper electrode 33 of the color filter substrate 30, a first common voltage having a larger amplitude than the reference voltage is applied to each first common electrode stripe 24a on the array substrate 20 through the first voltage line 201 and the first control switch 25a, and a second common voltage having a larger amplitude than the reference voltage is applied to each second common electrode stripe 24b on the array substrate 20 through the second voltage line 202 and the second control switch 25b, so that voltage differences between all the common electrode stripes 24 and the upper electrode 33 are greater than a second preset value (for example, greater than 2V), where the second preset value is greater than or equal to the first preset value. At this time, because the voltage difference between all the common electrode stripes 24 and the upper electrodes 33 is large, a strong vertical electric field E (as shown by arrows in fig. 20) is generated between the array substrate 20 and the color film substrate 30 in the liquid crystal cell, and because the negative liquid crystal molecules are deflected in the direction perpendicular to the electric field lines under the action of the electric field, the negative liquid crystal molecules are deflected under the action of the vertical electric field E, so that the inclination angle between the liquid crystal molecules and the

substrates

20 and 30 is reduced, the light leakage phenomenon of the liquid crystal display device at an oblique angle is correspondingly reduced, the contrast is improved and the viewing angle is increased in the oblique viewing direction, and the liquid crystal display device finally realizes wide viewing angle display.

Specifically, in the wide viewing angle mode, the reference voltage applied by the upper electrode 33 may be a constant 0V, the first ac control voltage V1 may be applied to the first voltage line 201, the second ac control voltage V2 may be applied to the second voltage line 202, and the magnitudes of the first common voltage applied to each first common electrode bar 24a and the second common voltage applied to each second common electrode bar 24b may be selected to be greater than 3V (i.e., | Vcom- | ≧ 3V, | Vcom + | 3V), for example, Vcom-equals to-3.6V, and Vcom + equals to +3.6V, so that the voltage difference between each common electrode bar 24 and the upper electrode 33 is greater than 3V, and a good wide viewing angle effect can be achieved.

Although the present invention has been described with reference to the preferred embodiments, it is to be understood that the present invention is not limited to the disclosed embodiments, and that various changes, modifications and equivalents may be made by those skilled in the art without departing from the scope of the invention.

Claims

1. A liquid crystal display device comprises a display panel (50), wherein the display panel (50) comprises an array substrate (20), a color film substrate (30) arranged opposite to the array substrate (20) and a liquid crystal layer (40) positioned between the array substrate (20) and the color film substrate (30), the array substrate (20) is provided with a plurality of scanning lines (21), a plurality of data lines (22) and a plurality of pixel units arranged in an array manner, the display panel (50) is provided with a display area and a non-display area, and the liquid crystal display device is characterized in that the array substrate (20) is further provided with a first voltage line (201), a second voltage line (202), a plurality of common electrode bars (24) and a plurality of control switches (25), the plurality of common electrode bars (24) are arranged in the display area of the display panel (50), and the first voltage line (201), the second voltage line (202) and the plurality of control switches (25) are arranged in the non-display area of the display panel (50), each common electrode bar (24) extends along a scanning line (21), the plurality of common electrode bars (24) includes a plurality of first common electrode bars (24a) and a plurality of second common electrode bars (24b), the plurality of first common electrode bars (24a) and the plurality of second common electrode bars (24b) are arranged at intervals from each other in a data line (22) direction, the plurality of control switches (25) include a plurality of first control switches (25a) and a plurality of second control switches (25b), each first common electrode bar (24a) is connected to the first voltage line (201) and a corresponding scanning line (21) through one first control switch (25a), and each second common electrode bar (24b) is connected to the second voltage line (202) and a corresponding scanning line (21) through one second control switch (25 b); the color film substrate (30) is provided with an upper electrode (33) which is arranged on the whole surface and is used for being matched with the common electrode strip (24) to switch different visual angle modes.

2. The liquid crystal display device according to claim 1, wherein a control terminal of each of the first control switches (25a) is connected to the corresponding scanning line (21), a first pass terminal of each of the first control switches (25a) is connected to the first voltage line (201), and a second pass terminal of each of the first control switches (25a) is connected to the corresponding first common electrode bar (24 a); the control end of each second control switch (25b) is connected with the corresponding scanning line (21), the first path end of each second control switch (25b) is connected with the second voltage line (202), and the second path end of each second control switch (25b) is connected with the corresponding second common electrode strip (24 b).

3. A liquid crystal display device as claimed in claim 1, characterized in that each common electrode strip (24) covers a respective entire row of pixel cells.

4. A liquid crystal display device according to claim 3, characterized in that each of the first common electrode stripes (24a) and each of the second common electrode stripes (24b) are alternately arranged with each other in the data line (22) direction; or, in the direction of the data line (22), every two first common electrode stripes (24a) and every two second common electrode stripes (24b) are arranged alternately.

5. The LCD device of claim 1, wherein the first common electrode bar (24a) corresponds to the pixels in an even numbered position in a row, and the second common electrode bar (24b) corresponds to the pixels in an odd numbered position in a row; or the first common electrode strip (24a) correspondingly covers the pixel units positioned at odd numbers in one row, and the second common electrode strip (24b) correspondingly covers the pixel units positioned at even numbers in one row.

6. A liquid crystal display device as claimed in claim 1, characterized in that the pixel cells in each row are connected to two scanning lines (21) on the upper and lower sides of the pixel cell in the row, respectively, and the common electrode strip (24) in each row is connected to the scanning line (21) on the upper or lower side of the pixel cell in the row via a corresponding control switch (25).

7. A liquid crystal display device as claimed in claim 1, characterized in that the individual pixel cells in each row are connected to the same scanning line (21), and the common electrode strip (24) of each row is connected to the scanning line (21) controlling the pixel cells of the row via a corresponding control switch (25).

8. The lcd device of claim 1, wherein the common electrode bar (24) in the nth row is connected to the (n-x) th scan line (21) through a corresponding control switch (25), wherein n is an integer greater than or equal to 1, and x is 1,2, or 3.

9. A liquid crystal display device as claimed in claim 1, characterized in that the pixel cells in each row are alternately connected to two scanning lines (21) on the upper and lower sides of the pixel cell in the row, the pixel cells in each column are alternately connected to two data lines (22) on the left and right sides of the pixel cell in the column, and the pixel cells in each row are charged only by the data lines (22) in the odd columns or only by the data lines (22) in the even columns.

10. A driving method for driving the liquid crystal display device according to any one of claims 1 to 9, characterized in that the driving method comprises:

in a first viewing angle mode, applying a reference voltage to the upper electrode (33), applying a first common voltage having a smaller magnitude than the reference voltage to each first common electrode bar (24a) through the first voltage line (201) and the first control switch (25a), and applying a second common voltage having a smaller magnitude than the reference voltage to each second common electrode bar (24b) through the second voltage line (202) and the second control switch (25b), so that a voltage difference between all the common electrode bars (24) and the upper electrode (33) is less than a first preset value;

in a second viewing angle mode, applying a reference voltage to the upper electrode (33), applying a first common voltage having a larger magnitude than the reference voltage to each first common electrode bar (24a) through the first voltage line (201) and the first control switch (25a), and applying a second common voltage having a larger magnitude than the reference voltage to each second common electrode bar (24b) through the second voltage line (202) and the second control switch (25b), so that a voltage difference between all the common electrode bars (24) and the upper electrode (33) is greater than a second preset value; wherein the second preset value is greater than or equal to the first preset value.

11. A driving method according to claim 10, wherein in the first viewing angle mode, the first common voltage applied to each of the first common electrode stripes (24a) and the second common voltage applied to each of the second common electrode stripes (24b) are the same as the reference voltage.

12. The driving method according to claim 10, wherein in the second viewing angle mode, a first ac control voltage (V1) is applied to the first voltage line (201), a second ac control voltage (V2) is applied to the second voltage line (202), the first ac control voltage (V1) and the second ac control voltage (V2) are in an inverse-phase complementary relationship, when the plurality of scanning lines (21) respectively apply the scanning signals, a first common voltage is respectively outputted to the plurality of first common electrode bars (24a) through the plurality of first control switches (25a), a second common voltage is respectively outputted to the plurality of second common electrode bars (24b) through the plurality of second control switches (25b), and polarities of the first common voltage and the second common voltage are opposite.

13. The driving method as claimed in claim 12, wherein the polarities of the first ac control voltage (V1) and the second ac control voltage (V2) are inverted every frame.

14. A driving method according to claim 12, wherein the polarity of the charged data voltage of the pixel cell covered by each first common electrode stripe (24a) is the same as the polarity of the first common voltage, and the polarity of the charged data voltage of the pixel cell covered by each second common electrode stripe (24b) is the same as the polarity of the second common voltage.

15. The driving method according to claim 10, wherein the liquid crystal layer (40) employs positive liquid crystal molecules, the first viewing angle mode is a wide viewing angle mode, and the second viewing angle mode is a narrow viewing angle mode; alternatively, the liquid crystal layer (40) uses negative liquid crystal molecules, and the first viewing angle mode is a narrow viewing angle mode and the second viewing angle mode is a wide viewing angle mode.