CN108681160B

CN108681160B - Liquid crystal display panel and driving method thereof

Info

Publication number: CN108681160B
Application number: CN201810196005.4A
Authority: CN
Inventors: 周学芹; 沈家军; 贺嘉伟; 张好好; 于德伟
Original assignee: InfoVision Optoelectronics Kunshan Co Ltd
Current assignee: InfoVision Optoelectronics Kunshan Co Ltd
Priority date: 2018-03-09
Filing date: 2018-03-09
Publication date: 2021-04-20
Anticipated expiration: 2038-03-09
Also published as: CN108681160A

Abstract

A liquid crystal display panel and a driving method thereof are provided, the liquid crystal display panel comprises a first substrate, a second substrate and a liquid crystal layer clamped between the first substrate and the second substrate, a common electrode and a pixel electrode are arranged on the first substrate, a visual angle control electrode is arranged on the second substrate, a plurality of sub-pixels arranged in an array are formed on the first substrate, the pixel electrode is arranged in each sub-pixel, the pixel electrode in each sub-pixel comprises a first pixel electrode part and a second pixel electrode part which are electrically connected together, the first pixel electrode part and the second pixel electrode part are respectively arranged in a first area and a second area, the liquid crystal alignment direction of the first area is a third direction, the liquid crystal alignment direction of the second area is a fourth direction, the third direction is vertical to the fourth direction, a first included angle formed between the first direction and the third direction and a second included angle formed between the second direction and the fourth direction are both larger than or equal to 5 degrees and smaller than or equal to 9 degrees.

Description

Liquid crystal display panel and driving method thereof

Technical Field

The invention relates to the technical field of liquid crystal display, in particular to a liquid crystal display panel and a driving method thereof.

Background

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.

The current display device gradually develops towards the direction of wide viewing angle, and no matter the application of mobile phone terminal, desktop display or notebook computer, besides the requirement of wide viewing angle, in many occasions, the display device is also required to have the function of switching between wide viewing angle and narrow viewing angle. At present, there are several ways to switch between a wide viewing angle and a narrow viewing angle of a liquid crystal display device.

The first is realized by attaching a shutter shielding film on the display screen, and when peep prevention is needed, the view angle can be reduced by shielding the screen by the shutter shielding film. However, in this method, an extra louver film is required to be prepared, which causes great inconvenience to a user, and one louver film can only realize one viewing angle, and once the louver film is attached, the viewing angle is fixed, and only a narrow viewing angle mode can be realized, and the wide viewing angle function cannot be displayed.

The second is to arrange a dual light source backlight system in the lcd device for adjusting the viewing angle of the lcd device, the dual light source backlight system is composed of two stacked light guide plates combined with an inverse prism sheet, the top light guide plate (LGP-T) combined with the inverse prism sheet changes the direction of the light so that the light is limited in a relatively narrow angular range, thereby realizing the narrow viewing angle of the lcd device, while the bottom light guide plate (LGP-B) combined with the inverse prism sheet functions to realize the wide viewing angle of the lcd device. However, such a dual-light source backlight system increases the thickness and cost of the liquid crystal display device, and is not suitable for the trend of thinning the liquid crystal display device.

The third is to apply a vertical electric field to the liquid crystal molecules by using a viewing angle control electrode on one side of a color filter substrate (CF), thereby realizing a narrow viewing angle mode. This mode can only realize the wide and narrow visual angle switching in the left and right direction, can not realize the wide and narrow visual angle switching in left and right direction and upper and lower direction simultaneously, can not realize all-round narrow visual angle promptly.

Disclosure of Invention

The invention aims to provide a liquid crystal display panel and a driving method thereof, which are used for realizing the visual angle switching between a wide visual angle and an omnibearing narrow visual angle according to different occasions.

The invention provides a liquid crystal display panel, which comprises a first substrate, a second substrate and a liquid crystal layer clamped between the first substrate and the second substrate, wherein a common electrode and a pixel electrode are arranged on the first substrate, a viewing angle control electrode is arranged on the second substrate, a plurality of sub-pixels which are arranged in an array manner are formed on the first substrate, the pixel electrode is arranged in each sub-pixel, the pixel electrode in each sub-pixel comprises a first pixel electrode part and a second pixel electrode part which are electrically connected together, the first pixel electrode part comprises a plurality of first pixel electrode strips which are arranged in parallel along a first direction at intervals, the second pixel electrode part comprises a plurality of second pixel electrode strips which are arranged in parallel along a second direction at intervals, the first pixel electrode part and the second pixel electrode part are respectively positioned in a first area and a second area, the liquid crystal alignment direction of the first area is a third direction, the liquid crystal alignment direction of the second region is a fourth direction, the third direction is perpendicular to the fourth direction, and a first included angle formed between the first direction and the third direction and a second included angle formed between the second direction and the fourth direction are both greater than or equal to 5 degrees and less than or equal to 9 degrees.

Further, each sub-pixel is divided into an upper area and a lower area by a horizontal reference line to form a first area and a second area, a pixel electrode in each sub-pixel includes a first pixel electrode part and a second pixel electrode part, and the first pixel electrode part and the second pixel electrode part are respectively arranged in the first area and the second area.

Further, an included angle formed between the first direction and the horizontal reference line is changed within a range of 50 ° to 54 °, and an included angle formed between the second direction and the horizontal reference line is also changed within a range of 50 ° to 54 °; the angle formed between the third direction and the horizontal reference line is 45 degrees, and the angle formed between the fourth direction and the horizontal reference line is 45 degrees.

Further, the included angle between the first direction and the horizontal reference line is 52 degrees, and the included angle between the second direction and the horizontal reference line is also 52 degrees; the angle between the third direction and the horizontal reference line is 45 degrees, and the angle between the fourth direction and the horizontal reference line is 45 degrees.

Furthermore, the first direction forms an angle of 7 degrees with the horizontal reference line, the second direction forms an angle of 83 degrees with the horizontal reference line, the third direction is parallel to the horizontal reference line, and the fourth direction is perpendicular to the horizontal reference line.

Further, the first direction is parallel to the horizontal reference line, the second direction is perpendicular to the horizontal reference line, the included angle between the third direction and the horizontal reference line is 7 degrees, and the included angle between the fourth direction and the horizontal reference line is 83 degrees.

Furthermore, each sub-pixel is divided into four regions in a shape of a Chinese character 'tian' by a horizontal reference line and a vertical reference line to form two first regions and two second regions, the two first regions are in a diagonal relationship, the two second regions are in a diagonal relationship, a pixel electrode in each sub-pixel comprises two first pixel electrode parts and two second pixel electrode parts, the two first pixel electrode parts are respectively arranged in the two first regions, and the two second pixel electrode parts are respectively arranged in the two second regions.

The present invention also provides a driving method of the liquid crystal display panel as described above, the driving method comprising:

in a first visual angle mode, applying a reference common voltage to a common electrode on a first substrate, and applying a first voltage signal with a smaller voltage difference relative to the reference common voltage to a visual angle control electrode on a second substrate, so that the voltage difference between the common electrode and the visual angle control electrode is smaller than a preset value;

in a second viewing angle mode, a reference common voltage is applied to the common electrode on the first substrate, and a second voltage signal having a larger voltage difference with respect to the reference common voltage is applied to the viewing angle control electrode on the second substrate, so that the voltage difference between the common electrode and the viewing angle control electrode is greater than a preset value.

Further, in the first viewing angle mode, the first voltage signal applied to the viewing angle control electrode is the same as the reference common voltage applied to the common electrode, so that the voltage difference between the common electrode and the viewing angle control electrode is zero; in the second viewing angle mode, the second voltage signal applied to the viewing angle control electrode is an alternating voltage, so that the voltage difference between the common electrode and the viewing angle control electrode is greater than or equal to 3V.

Further, the liquid crystal layer adopts positive liquid crystal molecules, the first visual angle mode is a wide visual angle mode, and the second visual angle mode is a narrow visual angle mode; alternatively, the liquid crystal layer 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.

In the liquid crystal display panel and the driving method thereof provided by the embodiments of the present invention, the pixel electrode in each sub-pixel includes a first pixel electrode portion and a second pixel electrode portion, the pixel electrode strip in the first pixel electrode portion and the pixel electrode strip in the second pixel electrode portion adopt different extending directions, the first region where the first pixel electrode portion is located and the second region where the second pixel electrode portion is located adopt different liquid crystal alignment directions, when a first included angle formed between the pixel electrode strip direction in the first pixel electrode portion and the liquid crystal alignment direction of the first region and a second included angle formed between the pixel electrode strip direction in the second pixel electrode portion and the liquid crystal alignment direction of the second region are both greater than or equal to 5 ° and less than or equal to 9 °, a viewing angle switching between a wide viewing angle and an omnidirectional narrow viewing angle can be realized by applying different viewing angle control voltage signals to the viewing angle control electrode, and a better peep-proof display effect can be realized at a narrow viewing angle.

Drawings

Fig. 1 is a partial cross-sectional view of a liquid crystal display panel according to an embodiment of the invention.

Fig. 2 is a schematic circuit diagram of the array substrate in fig. 1.

Fig. 3 is a schematic plan view of a single sub-pixel according to a first embodiment of the present invention.

FIG. 4 is a wide viewing angle iso-contrast viewing angle diagram according to the first embodiment of the present invention.

FIG. 5a is a view of an iso-contrast viewing angle at a viewing angle control voltage of 3V for a narrow viewing angle according to the first embodiment of the present invention.

FIG. 5b is a view of an iso-contrast viewing angle at a viewing angle control voltage of 4V for a narrow viewing angle according to the first embodiment of the present invention.

FIG. 5c is a view of an iso-contrast viewing angle at a viewing angle control voltage of 5V for a narrow viewing angle according to the first embodiment of the present invention.

FIG. 6a is a graph showing the relationship between the viewing angle and the contrast ratio in the Y-axis direction under different viewing angle control voltages for the narrow viewing angle in the first embodiment of the present invention.

FIG. 6b is a graph showing the relationship between the viewing angle and the contrast ratio in the X-axis direction under different viewing angle control voltages for the narrow viewing angle in the first embodiment of the present invention.

FIG. 7 is a diagram illustrating the relationship between the viewing angle and the contrast ratio in the Y-axis direction when the included angle between the pixel electrode bar direction and the liquid crystal alignment direction is different in the first embodiment of the present invention.

FIG. 8 is a diagram illustrating the relationship between the viewing angle and the contrast ratio in the X-axis direction when the included angle between the pixel electrode bar direction and the liquid crystal alignment direction is different in the first embodiment of the present invention.

FIG. 9 is a schematic plan view of a sub-pixel according to a second embodiment of the present invention.

FIG. 10 is a schematic plan view of a sub-pixel according to a third embodiment of the present invention.

FIG. 11 is a graph showing the relationship between the viewing angle and the contrast ratio in the Y-axis direction when the viewing angle is narrow according to the above three embodiments of the present invention.

FIG. 12 is a graph showing the relationship between the viewing angle and the contrast ratio in the X-axis direction when the viewing angle is narrow according to the three embodiments of the present invention.

FIG. 13 is a schematic plan view of a sub-pixel according to a fourth embodiment of the present invention.

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 ]

Fig. 1 is a partial cross-sectional view of a liquid crystal display panel according to an embodiment of the present invention, and referring to fig. 1, the liquid crystal display panel provided in this embodiment includes a first substrate 10, a second substrate 20, and a liquid crystal layer 30 sandwiched between the first substrate 10 and the second substrate 20, a first organic planarization layer 16, a common electrode 12, and a pixel electrode 140 are disposed on the first substrate 10, a viewing angle control electrode 21 and an organic planarization layer 26 are disposed on the second substrate 20, and the viewing angle control electrode 21 is used for controlling the liquid crystal display panel to switch between a wide viewing angle and a narrow viewing angle. It is to be understood that, in fig. 1, only the film layer structure related to the present invention is illustrated on the first substrate 10 and the second substrate 20, and other irrelevant structures are omitted. In each embodiment of the present invention, the liquid crystal molecules in the liquid crystal layer 30 are exemplified as positive liquid crystals.

Fig. 2 is a schematic circuit structure diagram of the array substrate in fig. 1, and referring to fig. 2, a plurality of sub-pixels 14 are defined on a first substrate 10 by scan lines 101 and data lines 102, and a pixel electrode 140 and a Thin Film Transistor (TFT)145 are disposed in each sub-pixel 14. The pixel electrode 140 is connected to the corresponding scan line 101 and data line 102 through a thin film transistor 145.

Fig. 3 is a schematic plan view of a single sub-pixel in the first embodiment of the present invention, please refer to fig. 3, each sub-pixel 14 is divided into two upper and lower regions, i.e., a first region K1 and a second region K2, by a horizontal reference line H, the pixel electrode 140 in each sub-pixel 14 includes a first pixel electrode portion 141 and a second pixel electrode portion 143 electrically connected together, and the first pixel electrode portion 141 and the second pixel electrode portion 143 are respectively disposed in the first region K1 and the second region K2. The first pixel electrode portion 141 includes a plurality of first pixel electrode bars 141a arranged in parallel along the first direction a1 at intervals, and the second pixel electrode portion 143 includes a plurality of second pixel electrode bars 143a arranged in parallel along the second direction a2 at intervals, specifically, each first pixel electrode bar 141a of the first pixel electrode portion 141 and each second pixel electrode bar 143a of the second pixel electrode portion 143 are electrically connected in a one-to-one correspondence manner. The liquid crystal alignment direction in the first region K1 of each sub-pixel 14 is the third direction B1, and the liquid crystal alignment direction in the second region K2 of each sub-pixel 14 is the fourth direction B2. Specifically, the alignment for initial alignment of the liquid crystals in the first and second regions K1 and K2 may be achieved by rubbing alignment, optical alignment, or the like.

As shown in fig. 3, in each sub-pixel 14, the plurality of first pixel electrode bars 141a are disposed along a first direction a1, the plurality of second pixel electrode bars 143a are disposed along a second direction a2, the liquid crystal alignment direction in the first region K1 is a third direction B1, and the liquid crystal alignment direction in the second region K2 is a fourth direction B2. The third direction B1 is perpendicular to the fourth direction B2, a first included angle is formed between the first direction a1 and the third direction B1, a second included angle is formed between the second direction a2 and the fourth direction B2, the first included angle and the second included angle are both greater than or equal to 5 degrees and less than or equal to 9 degrees, and when the first included angle and the second included angle are in the range, the liquid crystal display panel can achieve a good peep-proof display effect at a narrow viewing angle.

The magnitude of the first included angle may be equal to the magnitude of the second included angle, for example, the magnitudes of the first included angle and the second included angle are both 7 °, i.e., the first direction a1 forms an included angle of 7 ° with the third direction B1, and the second direction a2 forms an included angle of 7 ° with the fourth direction B2. The first angle may not be equal to the second angle, for example, the first angle is 6 °, i.e., the first direction a1 forms an angle of 6 ° with the third direction B1, and the second angle is 8 °, i.e., the second direction a2 forms an angle of 8 ° with the fourth direction B2. That is, in various embodiments of the present invention, the first angle and the second angle may be in the range of 5 ° or more and 9 ° or less, respectively.

In some embodiments, the angle β 1 between the first direction a1 and the horizontal reference line H varies from 50 ° to 54 °, and the angle β 2 between the second direction a2 and the horizontal reference line H also varies from 50 ° to 54 °; the third direction B1 forms an angle α 1 with the horizontal reference line H of 45 °, and the fourth direction B2 forms an angle α 2 with the horizontal reference line H of 45 °.

Specifically, in the present embodiment, an included angle β 1 between the first direction a1 and the horizontal reference line H is 52 °, and an included angle β 2 between the second direction a2 and the horizontal reference line H is also 52 °; the third direction B1 forms an angle α 1 with the horizontal reference line H of 45 °, and the fourth direction B2 forms an angle α 2 with the horizontal reference line H of 45 °. That is, in the present embodiment, the magnitude of the first included angle formed between the first direction a1 and the third direction B1 and the magnitude of the second included angle formed between the second direction a2 and the fourth direction B2 are both 7 °.

Fig. 4 is an iso-contrast viewing angle diagram of a wide viewing angle in the first embodiment of the present invention, in which the third direction B1 is taken as the positive X-axis direction in the viewing angle diagram, the direction parallel to and opposite to the third direction B1 is taken as the negative X-axis direction, the fourth direction B2 is taken as the negative Y-axis direction in the viewing angle diagram, and the direction parallel to and opposite to the fourth direction B2 is taken as the positive Y-axis direction in the viewing angle diagram. Referring to fig. 4, in the present embodiment, when wide viewing angle display is required, the reference common voltage applied to the common electrode 12 is 0V, the viewing angle control voltage applied to the viewing angle control electrode 21 is a first voltage signal and has a smaller voltage difference with respect to the reference common voltage, for example, the first voltage signal is 0V, at this time, the long axes of the liquid crystal molecules in the liquid crystal layer 30 are in a flat state, and the liquid crystal display panel can realize wide viewing angle display; when the reference common voltage applied to the common electrode 12 is 0V, the viewing angle control voltage applied to the viewing angle control electrode 21 is a second voltage signal and has a large voltage difference with respect to the reference common voltage, for example, the second voltage signal is greater than or equal to 3V, at this time, a strong vertical electric field is generated between the first substrate 10 and the second substrate 20 in the liquid crystal cell, the positive liquid crystal is deflected under the action of the vertical electric field, so that the long axes of the liquid crystal molecules in the liquid crystal layer 30 are erected, the liquid crystal molecules are changed from the lying posture to the inclined posture, the liquid crystal display panel has large-angle observation light leakage, the contrast is reduced in the oblique direction, the viewing angle is narrowed, and the liquid crystal display panel can realize narrow viewing angle display.

FIG. 5a is a view of an iso-contrast viewing angle at a viewing angle control voltage of 3V for a narrow viewing angle according to the first embodiment of the present invention. FIG. 5b is a view of an iso-contrast viewing angle at a viewing angle control voltage of 4V for a narrow viewing angle according to the first embodiment of the present invention. FIG. 5c is a view of an iso-contrast viewing angle at a viewing angle control voltage of 5V for a narrow viewing angle according to the first embodiment of the present invention. Table 1 shows the center contrast of the liquid crystal display panel at different viewing angle control voltages for a narrow viewing angle according to the first embodiment of the present invention. FIG. 6a is a graph showing the relationship between the viewing angle and the contrast ratio in the Y-axis direction under different viewing angle control voltages for a narrow viewing angle in the first embodiment of the present invention, and FIG. 6b is a graph showing the relationship between the viewing angle and the contrast ratio in the X-axis direction under different viewing angle control voltages for a narrow viewing angle in the first embodiment of the present invention.

TABLE 1

Operating mode voltage	3V	4V	5V
				Black state transmission rate	0.03％	0.06％	0.07％
White state transmittance	3.30％	2.04％	1.73％
				Center contrast ratio	110	34	24.7

With reference to fig. 5a to 5c, fig. 6a to 6B and table 1, when the included angle β 1 between the first direction a1 and the horizontal reference line H, the included angle β 2 between the second direction a2 and the horizontal reference line H are 52 °, and the included angle α 1 between the third direction B1 and the horizontal reference line H, and the included angle α 2 between the fourth direction B2 and the horizontal reference line H are 45 °, a reference common voltage of 0V is applied to the common electrode 12, and a viewing angle control voltage of 3V or more is applied to the viewing angle control electrode 21, so that the narrow viewing angle display of the liquid crystal display panel can be realized. The apparent angle control voltage is 3V in the curve I and the curve II, 4V in the curve II and the curve III, and 5V in the curve III and the curve III.

As can be seen from fig. 5a to 5c, fig. 6a to 6b and table 1, when the viewing angle control voltage applied to the viewing angle control electrode 21 is 3V, a good omni-directional narrow viewing angle cannot be achieved; when the viewing angle control voltage applied to the viewing angle control electrode 21 is 4V and 5V, a good omnidirectional narrow viewing angle effect can be achieved, and particularly, when the viewing angle control voltage applied to the viewing angle control electrode 21 is 4V, the omnidirectional narrow viewing angle effect can be achieved, and a high contrast ratio can also be achieved.

Table 2 shows the contrast ratio when the included angle between the pixel electrode strip direction and the liquid crystal alignment direction is different in the first embodiment of the present invention, and table 3 shows the center contrast ratio when the included angle between the pixel electrode strip direction and the liquid crystal alignment direction is different in the first embodiment of the present invention. The liquid crystal alignment directions are all selected to form 45 degrees with a horizontal reference line H, namely, the included angles alpha 1 and alpha 2 between the third direction B1 and the fourth direction B2 and the horizontal reference line H are both 45 degrees; the pixel electrode bar directions are selected to be changed within a range of 50 ° to 54 °, that is, included angles β 1 and β 2 between the first direction a1 and the second direction a2 and the horizontal reference line H are changed within a range of 50 ° to 54 °, so that an included angle between the pixel electrode bar directions and the liquid crystal alignment direction (i.e., a first included angle formed between the first direction a1 and the third direction B1 and a second included angle formed between the second direction a2 and the fourth direction B2) is changed within a range of 5 ° or more and 9 ° or less.

TABLE 2

TABLE 3

FIG. 7 is a diagram illustrating the relationship between the viewing angle and the contrast ratio in the Y-axis direction when the included angle between the pixel electrode bar direction and the liquid crystal alignment direction is different in the first embodiment of the present invention. FIG. 8 is a diagram illustrating the relationship between the viewing angle and the contrast ratio in the X-axis direction when the included angle between the pixel electrode bar direction and the liquid crystal alignment direction is different in the first embodiment of the present invention. As can be seen from fig. 7 to 8 and tables 2 and 3, when the reference common voltage applied to the common electrode 12 is 0V, and the viewing angle control voltage applied to the viewing angle control electrode 21 is 4V, and the first angle formed between the first direction a1 and the third direction B1 and the second angle formed between the second direction a2 and the fourth direction B2 are 9 °, 8 °, 7 °, 6 °, and 5 °, respectively, the liquid crystal display panel can achieve a better narrow viewing angle display effect.

Referring to fig. 7 and 8, an included angle α 1 between the third direction B1 and the horizontal reference line H and an included angle α 2 between the fourth direction B2 and the horizontal reference line H are both set to be 45 °, and when an included angle β 1 between the first direction a1 and the horizontal reference line H and an included angle β 2 between the second direction a2 and the horizontal reference line H are both set to be 52 °, please refer to a curve (c) and a curve (B) for the relationship between the viewing angle and the transmittance at this time; when the included angle beta 1 between the first direction A1 and the horizontal datum line H and the included angle beta 2 between the second direction A2 and the horizontal datum line H are both 54 degrees, the relationship between the visual angle and the contrast is referred to a curve I and a curve II; when the included angle β 1 between the first direction a1 and the horizontal reference line H and the included angle β 2 between the second direction a2 and the horizontal reference line H are both 53 °, the relationship between the viewing angle and the contrast is referred to by a curve (c) and a curve (c); when the included angle beta 1 between the first direction A1 and the horizontal datum line H and the included angle beta 2 between the second direction A2 and the vertical datum line H are both 51 degrees, the relationship between the visual angle and the contrast is referred to as a curve (r) and a curve (ninu); when the angle β 1 between the first direction a1 and the horizontal reference line H and the angle β 2 between the second direction a2 and the horizontal reference line H are both 50 °, the relationship between the viewing angle and the contrast ratio shall be referred to by the curves (fif) and (r) in curve (r).

Referring to fig. 7 to 8 and tables 2 and 3, when the viewing angle control voltage applied to the viewing angle control electrode 21 is 4V, and the first angle between the first direction a1 and the third direction B1 and the second angle between the second direction a2 and the fourth direction B2 are 9 °, 8 °, 7 °, 6 °, and 5 °, respectively, a good peep-proof effect is obtained at a narrow viewing angle. Particularly, when the included angles β 1 and β 2 between the first direction a1 and the second direction a2 and the horizontal reference line H are both 52 °, and the included angles α 1 and α 2 between the third direction B1 and the fourth direction B2 and the horizontal reference line H are both 45 °, that is, when the first included angle between the first direction a1 and the third direction B1 and the second included angle between the second direction a2 and the fourth direction B2 are both 7 °, the contrast ratios of the upper part, the lower part, the left part and the right part are consistent, an omnidirectional narrow viewing angle can be realized, and the optimal peeping prevention effect and the optimal brightness are achieved at the narrow viewing angle.

[ second embodiment ]

Fig. 9 is a schematic plan view of a sub-pixel in a second embodiment of the present invention, please refer to fig. 9, in this embodiment, each sub-pixel 14 is divided into an upper area and a lower area by a horizontal reference line H, that is, a first area K1 and a second area K2, a pixel electrode 140 in each sub-pixel 14 includes a first pixel electrode portion 141 and a second pixel electrode portion 143, and the first pixel electrode portion 141 and the second pixel electrode portion 143 are electrically connected together and respectively disposed in the first area K1 and the second area K2. The first pixel electrode part 141 includes a plurality of first pixel electrode bars 141a arranged in parallel at intervals, the second pixel electrode part 143 includes a plurality of second pixel electrode bars 143a arranged in parallel at intervals, the plurality of first pixel electrode bars 141a are disposed along the first direction a1, the plurality of second pixel electrode bars 143a are disposed along the second direction a2, the liquid crystal alignment direction in the first region K1 is the third direction B1, and the liquid crystal alignment direction in the second region K2 is the fourth direction B2. The third direction B1 is perpendicular to the fourth direction B2, a first included angle is formed between the first direction a1 and the third direction B1, a second included angle is formed between the second direction a2 and the fourth direction B2, the first included angle and the second included angle are both greater than or equal to 5 degrees and less than or equal to 9 degrees, and when the first included angle and the second included angle are in the range, the display panel can achieve a good display effect at both a wide viewing angle and a narrow viewing angle.

Specifically, in the present embodiment, the included angle β 1 between the first direction a1 and the horizontal reference line H is 7 °, the included angle β 2 between the second direction a2 and the horizontal reference line H is 83 °, the third direction B1 is parallel to the horizontal reference line H, and the fourth direction B2 is perpendicular to the horizontal reference line H, that is, the first included angle between the first direction a1 and the third direction B1 and the second included angle between the second direction a2 and the fourth direction B2 are both 7 °.

[ third embodiment ]

Fig. 10 is a schematic plan view of a sub-pixel in a third embodiment of the present invention, please refer to fig. 10, in this embodiment, each sub-pixel 14 is divided into an upper area and a lower area by a horizontal reference line H, i.e., a first area K1 and a second area K2, a pixel electrode 140 in each sub-pixel 14 includes a first pixel electrode portion 141 and a second pixel electrode portion 143, and the first pixel electrode portion 141 and the second pixel electrode portion 143 are electrically connected together and respectively disposed in the first area K1 and the second area K2. The first pixel electrode part 141 includes a plurality of first pixel electrode bars 141a arranged in parallel at intervals, the second pixel electrode part 143 includes a plurality of second pixel electrode bars 143a arranged in parallel at intervals, the plurality of first pixel electrode bars 141a are disposed along the first direction a1, the plurality of second pixel electrode bars 143a are disposed along the second direction a2, the liquid crystal alignment direction in the first region K1 is the third direction B1, and the liquid crystal alignment direction in the second region K2 is the fourth direction B2. The third direction B1 is perpendicular to the fourth direction B2, a first included angle is formed between the first direction a1 and the third direction B1, a second included angle is formed between the second direction a2 and the fourth direction B2, the first included angle and the second included angle are both greater than or equal to 5 degrees and less than or equal to 9 degrees, and when the first included angle and the second included angle are in the range, the display panel can achieve a good display effect at both a wide viewing angle and a narrow viewing angle.

Specifically, in the present embodiment, the first direction a1 is parallel to the horizontal reference line H, the second direction a2 is perpendicular to the horizontal reference line H, the included angle α 1 between the third direction B1 and the horizontal reference line H is 7 °, the included angle α 2 between the fourth direction B2 and the horizontal reference line H is 83 °, that is, the first included angle formed between the first direction a1 and the third direction B1 and the second included angle formed between the second direction a2 and the fourth direction B2 are both 7 °.

FIG. 11 is a graph showing the relationship between the viewing angle and the contrast ratio in the Y-axis direction when the viewing angle is narrow according to the above three embodiments of the present invention. FIG. 12 is a graph showing the relationship between the viewing angle and the contrast ratio in the X-axis direction when the viewing angle is narrow according to the three embodiments of the present invention. Table 4 shows the viewing angle and contrast data of three different structures of the sub-pixels in the Y-axis direction and the X-axis direction, wherein the first structure is the first embodiment of the present invention, the second structure is the second embodiment of the present invention, and the third structure is the third embodiment of the present invention. Here, in the narrow viewing angle, the viewing angle control voltage applied to the viewing angle control electrode 21 is 4V.

TABLE 4

Referring to fig. 11 and 12, curves (r) and (r) are graphs showing the relationship between the viewing angle and the contrast of the display panel in the Y-axis direction and the X-axis direction, respectively, according to the first embodiment of the present invention. Curve c and curve c in the figure are the relationship diagrams of the viewing angle and the contrast of the display panel in the Y-axis direction and the X-axis direction, respectively, in the second embodiment of the present invention. It can be seen that the contrast ratios in the Y-axis direction and the X-axis direction of the display panels in the first embodiment and the second embodiment have good symmetry at a narrow viewing angle, and can achieve a better display effect. In the figure, the curve (c) and the curve (c) are the relationship between the viewing angle and the contrast of the display panel in the Y-axis direction and the X-axis direction, respectively, according to the third embodiment of the present invention. It can be seen that the contrast ratio between the Y-axis direction and the X-axis direction of the display panel in the third embodiment has no symmetry at the narrow viewing angle, but a certain narrow viewing angle display effect can be achieved.

[ fourth embodiment ]

FIG. 13 is a schematic plan view of a sub-pixel according to a fourth embodiment of the present invention. In this embodiment, each sub-pixel 14 includes two first pixel electrode portions 141 and two second pixel electrode portions 143, and the two first pixel electrode portions 141 and the two second pixel electrode portions 143 are electrically connected to each other. Each sub-pixel 14 is provided with a horizontal reference line H and a vertical reference line V, the horizontal reference line H and the vertical reference line V have an intersection, the two first pixel electrode portions 141 are centrosymmetric with respect to the intersection, and the two second pixel electrode portions 143 are centrosymmetric with respect to the intersection. Each sub-pixel 14 is divided into four regions in a shape of "tian" by a horizontal reference line H and a vertical reference line V, and includes two first regions K1 and two second regions K2, the two first regions K1 are in a diagonal relationship, the two second regions K2 are in a diagonal relationship, the two first pixel electrode portions 141 are respectively disposed in the two first regions K1, and the two second pixel electrode portions 143 are respectively disposed in the two second regions K2. Each of the first pixel electrode parts 141 includes a plurality of first pixel electrode bars 141a arranged in parallel at intervals in the first direction a1, each of the second pixel electrode parts 143 includes a plurality of second pixel electrode bars 143a arranged in parallel at intervals in the second direction a2, the liquid crystal alignment direction in each of the first regions K1 is the third direction B1, and the liquid crystal alignment direction in each of the second regions K2 is the fourth direction B2.

The third direction B1 is perpendicular to the fourth direction B2, a first included angle is formed between the first direction a1 and the third direction B1, a second included angle is formed between the second direction a2 and the fourth direction B2, the first included angle and the second included angle are both greater than or equal to 5 ° and less than or equal to 9 °, that is, the included angle between the pixel electrode bar direction and the liquid crystal alignment direction in each region is greater than or equal to 5 ° and less than or equal to 9 °, and when the included angle is within the range, the liquid crystal display panel can achieve a good peep-proof display effect at a narrow viewing angle.

[ fifth embodiment ]

The present invention also provides a driving method of the liquid crystal display panel, including:

in a first viewing angle mode, a reference common voltage is applied to the common electrode 12 on the first substrate 10, and a first voltage signal having a smaller voltage difference with respect to the reference common voltage is applied to the viewing angle control electrode 21 on the second substrate 20, so that the voltage difference between the common electrode 12 and the viewing angle control electrode 21 is smaller than a preset value;

in the second viewing angle mode, a reference common voltage is applied to the common electrode 12 on the first substrate 10, and a second voltage signal having a large voltage difference with respect to the reference common voltage is applied to the viewing angle control electrode 21 on the second substrate 20, so that the voltage difference between the common electrode 12 and the viewing angle control electrode 21 is greater than a preset value.

Preferably, in the first viewing angle mode, the first voltage signal applied to the viewing angle control electrode 21 is the same as the reference common voltage applied to the common electrode 12, for example, 0V, and the voltage difference between the common electrode 12 and the viewing angle control electrode 21 is zero.

Preferably, in the second viewing angle mode, the reference common voltage applied to the common electrode 12 is, for example, 0V, and the second voltage signal applied to the viewing angle control electrode 21 is, for example, an ac voltage greater than or equal to 3V, and at this time, the voltage difference between the common electrode 12 and the viewing angle control electrode 21 is large, and the liquid crystal display panel can achieve a good narrow viewing angle display effect.

As described above, when the liquid crystal layer 30 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.

It is to be understood that the liquid crystal layer 30 may also employ negative liquid crystal molecules. When the liquid crystal layer 30 uses negative liquid crystal molecules, the first viewing angle mode is a narrow viewing angle mode, and the second viewing angle mode is a wide viewing angle mode.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A liquid crystal display panel comprises a first substrate (10), a second substrate (20) and a liquid crystal layer (30) clamped between the first substrate (10) and the second substrate (20), wherein a common electrode (12) and a pixel electrode (140) are arranged on the first substrate (10), a viewing angle control electrode (21) is arranged on the second substrate (20), a plurality of sub-pixels (14) are formed on the first substrate (10) in an array arrangement, the pixel electrode (140) is arranged in each sub-pixel (14), each sub-pixel (14) is divided into an upper area and a lower area by a horizontal reference line (H) to form a first area (K1) and a second area (K2), and the pixel electrode (140) in each sub-pixel (14) comprises a first pixel electrode part (141) and a second pixel electrode part (143), the first pixel electrode portion (141) and the second pixel electrode portion (143) are respectively disposed within the first region (K1) and the second region (K2); or, each sub-pixel (14) is divided into four regions in a shape of a Chinese character 'tian' by a horizontal reference line (H) and a vertical reference line (V) to form two first regions (K1) and two second regions (K2), the two first regions (K1) are in a diagonal relationship, the two second regions (K2) are in a diagonal relationship, the pixel electrode (140) in each sub-pixel (14) comprises two first pixel electrode parts (141) and two second pixel electrode parts (143), the two first pixel electrode parts (141) are respectively arranged in the two first regions (K1), and the two second pixel electrode parts (143) are respectively arranged in the two second regions (K2);

the first pixel electrode part (141) comprises a plurality of first pixel electrode strips (141a) arranged in parallel at intervals along a first direction (A1), the second pixel electrode part (143) comprises a plurality of second pixel electrode strips (143a) arranged in parallel at intervals along a second direction (A2), the liquid crystal alignment direction of the first region (K1) is a third direction (B1), the liquid crystal alignment direction of the second region (K2) is a fourth direction (B2), the third direction (B1) is perpendicular to the fourth direction (B2), and a first included angle formed between the first direction (A1) and the third direction (B1) and a second included angle formed between the second direction (A2) and the fourth direction (B2) are both greater than or equal to 5 degrees and less than or equal to 9 degrees.

2. The liquid crystal display panel according to claim 1, wherein an angle formed between the first direction (a1) and the horizontal reference line (H) varies within a range of 50 ° to 54 °, and an angle formed between the second direction (a2) and the horizontal reference line (H) also varies within a range of 50 ° to 54 °; an angle formed between the third direction (B1) and the horizontal reference line (H) is 45 °, and an angle formed between the fourth direction (B2) and the horizontal reference line (H) is 45 °.

3. The liquid crystal display panel according to claim 2, wherein the first direction (a1) makes an angle of 52 ° with the horizontal reference line (H), and the second direction (a2) makes an angle of 52 ° with the horizontal reference line (H); the third direction (B1) forms an angle of 45 degrees with the horizontal reference line (H), and the fourth direction (B2) forms an angle of 45 degrees with the horizontal reference line (H).

4. The liquid crystal display panel of claim 1, wherein the first direction (a1) makes an angle of 7 ° with the horizontal reference line (H), the second direction (a2) makes an angle of 83 ° with the horizontal reference line (H), the third direction (B1) is parallel to the horizontal reference line (H), and the fourth direction (B2) is perpendicular to the horizontal reference line (H).

5. The lcd panel of claim 1, wherein the first direction (a1) is parallel to the horizontal reference line (H), the second direction (a2) is perpendicular to the horizontal reference line (H), the third direction (B1) forms an angle of 7 ° with the horizontal reference line (H), and the fourth direction (B2) forms an angle of 83 ° with the horizontal reference line (H).

6. A driving method of the liquid crystal display panel according to any one of claims 1 to 5, characterized by comprising:

in a first viewing angle mode, applying a reference common voltage to a common electrode (12) on the first substrate (10), and applying a first voltage signal with a smaller voltage difference relative to the reference common voltage to a viewing angle control electrode (21) on the second substrate (20), so that the voltage difference between the common electrode (12) and the viewing angle control electrode (21) is smaller than a preset value;

in a second viewing angle mode, a reference common voltage is applied to the common electrode (12) on the first substrate (10), and a second voltage signal with a larger voltage difference relative to the reference common voltage is applied to the viewing angle control electrode (21) on the second substrate (20), so that the voltage difference between the common electrode (12) and the viewing angle control electrode (21) is larger than a preset value.

7. The driving method according to claim 6, wherein in the first viewing angle mode, the first voltage signal applied to the viewing angle control electrode (21) is the same as the reference common voltage applied to the common electrode (12), so that the voltage difference between the common electrode (12) and the viewing angle control electrode (21) is zero; in a second viewing angle mode, a second voltage signal applied to the viewing angle control electrode (21) is an alternating voltage, so that a voltage difference between the common electrode (12) and the viewing angle control electrode (21) is greater than or equal to 3V.

8. The driving method according to claim 6, wherein the liquid crystal layer (30) 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; or, the liquid crystal layer (30) adopts negative liquid crystal molecules, the first visual angle mode is a narrow visual angle mode, and the second visual angle mode is a wide visual angle mode.