Pixel circuit, pixel driving method and display panel

Abstract

The present application belongs to the field of display driving technology, and specifically relates to a pixel circuit, a pixel driving method and a display panel. The pixel circuit includes: a first switch tube, a liquid crystal capacitor, a voltage neutralization unit and a reset unit; the first end of the voltage neutralization unit is connected to the first end of the liquid crystal capacitor, and the voltage neutralization unit is used to neutralize the voltage in the liquid crystal capacitor at the end of charging; the reset unit is used to reset the voltage in the voltage neutralization unit during the charging stage; the present application neutralizes the voltage in the liquid crystal capacitor after charging through the voltage neutralization unit, so that the liquid crystal molecules rotate multiple times within one frame, so that the emitted light can have different emission angles, which greatly improves the display viewing angle and also improves the transmittance of the display panel.

Description

Technical Field

[0001] The present disclosure belongs to the field of display driving technology, and in particular relates to a pixel circuit, a pixel driving method and a display panel. Background Art

[0002] At present, the 8domain sub-pixel design method is usually used to increase the viewing angle of the display screen, that is, one sub-pixel is divided into two parts: main (main sub-pixel) and sub (sub-sub-pixel). When driving, the main and sub are charged to different voltage levels, so that the main and sub brightness are different. When viewed from a wide viewing angle, the rotation angles of the main and sub liquid crystals in one sub-pixel are not in the same direction, the human eye has a better accumulation effect, and the problem of color shift is better solved, thereby increasing the viewing angle of the display screen; however, the 8 domain pixel design has the problem of low transmittance.

[0003] It can be seen that the pixel circuit design in the prior art reduces the problem of display panel transmittance while improving the display viewing angle. Summary of the invention

[0004] The present application provides a pixel circuit, a pixel driving method and a display panel, which solve the problem in the prior art of reducing the transmittance of the display panel while improving the display viewing angle.

[0005] In a first aspect, the present application provides a pixel circuit, which includes: a first switch tube, a liquid crystal capacitor, a voltage neutralization unit and a reset unit; the control end of the first switch tube is connected to a first scan line providing a first scan voltage, the first end of the first switch tube is connected to a data line providing a grayscale voltage, the second end of the first switch tube is connected to a first end of the liquid crystal capacitor, and the second end of the liquid crystal capacitor is connected to a first common electrode providing a first common voltage; the first end of the voltage neutralization unit is connected to the first end of the liquid crystal capacitor, and the second end of the voltage neutralization unit is connected to a second common electrode providing a second common voltage, and is used to neutralize the voltage in the liquid crystal capacitor at the end of charging, so that the liquid crystal molecules in the liquid crystal capacitor rotate multiple times within one frame; the control end of the reset unit is connected to the first scan line, the first end of the reset unit is connected to the third end of the voltage neutralization unit, and the second end of the reset unit is connected to the second common electrode, and the reset unit is used to reset the voltage in the voltage neutralization unit during the charging stage.

[0006] Optionally, the reset unit includes: a second switch tube, a control end of the second switch tube is connected to the first scan line, a first end of the second switch tube is connected to the third end of the voltage neutralization unit, and a second end of the second switch tube is connected to the second common electrode.

[0007] Optionally, the voltage neutralization unit includes: a first resistor and a first neutralization capacitor; the first end of the first resistor is connected to the first end of the liquid crystal capacitor, the second end of the first resistor is respectively connected to the first end of the first neutralization capacitor and the first end of the reset unit, and the second end of the first neutralization capacitor is connected to the second common electrode.

[0008] Optionally, the voltage neutralization unit includes: a third switch tube, and a second neutralization capacitor;

[0009] The control end of the third switch tube is connected to the second scan line providing a second scan voltage, the first end of the third switch tube is connected to the first end of the liquid crystal capacitor, the second end of the third switch tube is respectively connected to the first end of the second neutralization capacitor and the first end of the reset unit, and the second end of the second neutralization capacitor is connected to the second common electrode.

[0010] Optionally, the voltage neutralization unit further includes: a second resistor, a first end of the second resistor is connected to the second end of the third switch tube, and a second end of the second resistor is respectively connected to the first end of the second neutralization capacitor and the first end of the reset unit.

[0011] Optionally, the voltage neutralization unit performs voltage neutralization based on the following relationship:

[0012]

[0013] in, Indicates the voltage drop value of the liquid crystal capacitor, Indicates the voltage rise value of the first neutralizing capacitor or the second neutralizing capacitor, Represents the grayscale voltage, represents the second common voltage, Indicates the capacitance parameter of liquid crystal capacitor, Indicates the capacitance parameter of the first neutralization capacitor or the second neutralization capacitor.

[0014] Optionally, the pixel circuit further includes: a storage capacitor, a first end of the storage capacitor is connected to the first end of the liquid crystal capacitor, and a second end of the storage capacitor is connected to the second common electrode.

[0015] Optionally, an absolute value of the gray scale voltage is greater than that of the second common voltage.

[0016] In the second aspect, the present application provides a pixel driving method, which is applied to the pixel circuit, and the driving method includes: in the charging stage, the first scanning line outputs a first scanning voltage to turn on the first switch tube, and charges the liquid crystal capacitor to the grayscale voltage output by the data line, and at the same time, the voltage in the voltage neutralization unit is reset by the reset unit; in the display stage, the first scanning line stops outputting the first scanning voltage to turn off the first switch tube, and the voltage in the liquid crystal capacitor is neutralized by the voltage neutralization unit until the voltage in the voltage neutralization unit is equal to the voltage in the liquid crystal capacitor.

[0017] Optionally, the voltage neutralization unit includes: a third switch tube, and a second neutralization capacitor; the control end of the third switch tube is connected to the second scan line providing the second scan voltage, the first end of the third switch tube is connected to the first end of the liquid crystal capacitor, the second end of the third switch tube is respectively connected to the first end of the second neutralization capacitor and the first end of the reset unit, and the second end of the second neutralization capacitor is connected to the second common electrode;

[0018] The driving method also includes: in the charging stage, the second scan line stops outputting the second scan voltage to turn off the third switch tube; in the display stage, within a preset time after the first scan line stops outputting the first scan voltage, the second scan line outputs the second scan voltage to turn on the third switch tube, and the voltage in the liquid crystal capacitor is neutralized by the second neutralization capacitor until the voltage in the second neutralization capacitor is equal to that in the liquid crystal capacitor.

[0019] In a third aspect, the present application provides a display panel, comprising a plurality of first scan lines providing a first scan voltage and a plurality of data lines providing a grayscale voltage, and the display panel further comprises the pixel circuit.

[0020] Optionally, when the voltage neutralization unit includes a third switch tube, the display panel further includes a plurality of second scan lines; wherein the control end of the third switch tube is connected to the second scan line.

[0021] The technical solution provided by this application has at least the following beneficial effects:

[0022] The present application neutralizes the voltage in the liquid crystal capacitor after charging through a voltage neutralization unit, so that the liquid crystal molecules rotate multiple times within one frame, so that the emitted light can have different emission angles, greatly improving the display viewing angle; therefore, compared with the 8domain pixel design, the present application improves the display viewing angle while improving the transmittance of the display panel; in addition, the voltage in the voltage neutralization unit in the charging stage is reset through a reset unit to prevent the residual voltage after the voltage neutralization of the previous frame from affecting the display of the current frame, thereby improving the display stability of the display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0024] Figure 1 Shown is a schematic structural diagram of a pixel circuit provided in an embodiment of the present application.

[0025] Figure 2 Shown is a circuit diagram of a first pixel circuit provided in an embodiment of the present application.

[0026] Figure 3 FIG. 1 is a schematic diagram showing the relationship between the voltage on the liquid crystal capacitor and the display brightness in the prior art.

[0027] Figure 4 FIG. 1 is a schematic diagram showing the relationship between the voltage on the first liquid crystal capacitor and the display brightness provided in an embodiment of the present application.

[0028] Figure 5 Shown is a circuit schematic diagram of a second pixel circuit provided in an embodiment of the present application.

[0029] Figure 6 FIG. 1 is a schematic diagram showing the relationship between the voltage on the second liquid crystal capacitor and the display brightness provided in an embodiment of the present application.

[0030] Figure 7 Shown is a circuit diagram of a third pixel circuit provided in an embodiment of the present application.

[0031] Figure 8 The figure is a schematic flow chart of a first pixel driving method provided in an embodiment of the present application.

[0032] Fig. 9 FIG. 1 is a flow chart of a second pixel driving method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more comprehensive and complete and fully convey the concept of example embodiments to those skilled in the art.

[0034] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the present application.

[0035] The present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be understood as limiting the present application.

[0036] In order to increase the display viewing angle of the display screen, the inventor proposed a method of adjusting the wide viewing angle through a driving method based on the conventional 4domain pixel design, so that adjacent sub-pixels have a brightness difference to simulate the effect of 8domain, and also spatially split the picture into two brightness mixtures. This method can improve the panel penetration rate while improving the panel viewing angle.

[0037] However, in the flip pixel architecture Column driven LCD (liquid crystal display) screen's flickering screen, only one polarity sub-pixel is lit in the same frame, such as all positive in the first frame, and the next frame the entire screen's polarity is reversed, making all negative sub-pixels lit. Even if the brightness is adjusted as much as possible to be the same at the same grayscale for positive and negative polarities, there is actually still a difference in brightness due to the stability and uniformity of the process and the influence of parasitic capacitance. This difference will be maximized when displaying the flickering screen, resulting in a flickering screen problem.

[0038] Based on this, the present application provides a pixel circuit, which specifically includes the following embodiments:

[0039] Embodiment 1

[0040] Figure 1 FIG. 1 is a schematic diagram of a pixel circuit structure provided in an embodiment of the present application; Figure 1 As shown, the pixel circuit 100 is applied to a display panel, which includes a plurality of first scan lines 300 providing a first scan voltage, a plurality of data lines 200 providing a grayscale voltage, and a plurality of pixel circuits 100 defined by the intersection of the plurality of first scan lines 300 and the plurality of data lines 200.

[0041] The pixel circuit 100 includes: a first switch tube T1, a liquid crystal capacitor Clc, a voltage neutralization unit 110 and a reset unit 120; the control end of the first switch tube T1 is connected to a first scan line 300 providing a first scan voltage, the first end of the first switch tube T1 is connected to a data line 200 providing a grayscale voltage, the second end of the first switch tube T1 is connected to a first end of the liquid crystal capacitor Clc, and the second end of the liquid crystal capacitor Clc is connected to a first common electrode Vcom providing a first common voltage; the first end of the voltage neutralization unit 110 is connected to a first end of the liquid crystal capacitor Clc, and the second end of the voltage neutralization unit 110 is connected to a second common electrode AVcom providing a second common voltage, and is used to neutralize the voltage in the liquid crystal capacitor Clc at the end of charging, so that the liquid crystal molecules in the liquid crystal capacitor rotate multiple times within one frame; the control end of the reset unit 120 is connected to the first scan line 300, the first end of the reset unit 120 is connected to a third end of the voltage neutralization unit 110, and the second end of the reset unit 120 is connected to the second common electrode AVcom, and the reset unit 120 is used to reset the voltage in the voltage neutralization unit 110 during the charging stage.

[0042] It should be noted that the display panel also includes a liquid crystal layer ( Figure 1 (not shown in the figure), the two electrodes of the liquid crystal capacitor Clc in the pixel circuit 100 are respectively arranged on the upper and lower sides of the liquid crystal layer. When the first switch tube T1 is turned on under the loading of the first scanning voltage transmitted on the first scanning line 300, the two electrodes of the liquid crystal capacitor Clc form an electric field under the loading of the first common voltage transmitted by the first common electrode Vcom and the data signal transmitted on the data line 200, so as to control the rotation angle of the liquid crystal molecules in the liquid crystal layer, thereby adjusting the transmittance of the light emitted by the backlight source, and finally realizing the display function of the display panel.

[0043] The display panel also includes an array substrate, and the first common electrode Vcom and the second common electrode AVcom are respectively arranged on the array substrate; the voltage values ​​of the common voltage signals transmitted on the first common electrode Vcom and the second common electrode AVcom can be the same or different; the first switch tube T1 can be a P-type semiconductor metal oxide transistor or an N-type semiconductor metal oxide transistor, and the present application does not limit this. Figure 1 As shown, “Gn” represents the first scan line 300 of the nth row, and “Sn” represents the data line 200 of the nth column.

[0044] The working principle of the pixel circuit 100 provided in this embodiment is:

[0045] During the charging stage, the first scanning line 300 outputs the first scanning voltage to turn on the first switch tube T1, and charges the liquid crystal capacitor Clc to the grayscale voltage of the display data (that is, the data signal output on the data line 200); at the same time, the voltage in the voltage neutralization unit 110 is reset through the reset unit 120, that is, the voltage output from the third end of the voltage neutralization unit 110 is reset to a preset initial value to prevent the existence of a residual voltage; wherein the preset initial value can be the second common voltage.

[0046] In the display stage, when the first scanning line 300 stops outputting the first scanning voltage, it indicates that the charging stage of one row is over, and the normal picture is displayed in the display stage; when the charging of the liquid crystal capacitor Clc stops, the voltage on the liquid crystal capacitor Clc becomes higher than the voltage corresponding to the lower rotation angle of the liquid crystal, and the liquid crystal rotates to a brighter angle; at the same time, the liquid crystal capacitor Clc forms a loop with the voltage neutralization unit 110, and the charge stored in the liquid crystal capacitor Clc is transferred to the voltage neutralization unit 110 until the voltage in the liquid crystal capacitor Clc is equal to that in the voltage neutralization unit 110, and in this stage, the liquid crystal rotates to a darker angle as the voltage of the liquid crystal capacitor Clc gradually decreases, and the liquid crystal stops rotating at the moment when the voltage is neutralized; at the beginning of the next charging stage, the display of one frame is completed.

[0047] Therefore, the present application neutralizes the voltage in the liquid crystal capacitor Clc after charging through the voltage neutralization unit 110, so that the liquid crystal molecules rotate multiple times within one frame, so that the emitted light can have different emission angles, greatly improving the display viewing angle; and the present application makes improvements based on the 4domain pixel design, and compared with the 8 domain pixel design, the transmittance of the display panel is improved; in addition, the voltage in the voltage neutralization unit 110 in the charging stage is reset through the reset unit to prevent the residual voltage after the voltage neutralization of the previous frame from affecting the display of the current frame, thereby improving the stability of the display panel.

[0048] Embodiment 2

[0049] In one embodiment of the present application, Figure 2 As shown, the reset unit 120 includes:

[0050] The second switch tube T2, the control end of the second switch tube T2 is connected to the first scan line 300, the first end of the second switch tube T2 is connected to the third end of the voltage neutralization unit 110, and the second end of the second switch tube T2 is connected to the second common electrode AVcom.

[0051] The voltage neutralization unit 110 includes: a first resistor R1 and a first neutralization capacitor Cz1; the first end of the first resistor R1 is connected to the first end of the liquid crystal capacitor Clc, the second end of the first resistor R1 is respectively connected to the first end of the first neutralization capacitor Cz1 and the first end of the reset unit 120, and the second end of the first neutralization capacitor Cz1 is connected to the second common electrode AVcom.

[0052] It should be noted that, taking the first scan line 300Gn in the nth row as an example, the working principle of the pixel circuit in this embodiment is as follows:

[0053] First, when Gn outputs a high level, the first switch tube T1 and the second switch tube T2 are turned on at the same time, and the liquid crystal capacitor Clc is charged to the grayscale voltage level (i.e., the data signal output by the data line) through the first switch tube T1, and the first neutralization capacitor Cz1 is charged to the second common voltage through the second switch tube T2; in addition, since the first switch tube T1 and the second switch tube T2 are turned on at the same time, the charge of the liquid crystal capacitor Clc will leak from the first resistor R1 to the second common electrode AVcom. Compared with charging, the leakage is so small that it can be ignored. Therefore, the liquid crystal capacitor Clc will eventually be charged to the grayscale voltage level of the display data, and the first neutralization capacitor Cz1 will be charged to the voltage level of the second common electrode AVcom. In addition, the purpose of charging the first neutralization capacitor Cz1 to the second common voltage each time is to reset the voltage at the second end of the first resistor R1 to prevent the display of this frame from being affected by the voltage left after the neutralization of the previous frame.

[0054] Then, when Gn outputs a low level, the charging time of the current row ends and the normal picture begins to be displayed. At the same time, during the remaining scanning time of several thousand rows in a frame, the liquid crystal capacitor Clc will neutralize the voltage with the first neutralization capacitor Cz1 through the first resistor R1. Since the voltage at the first end of the first resistor R1 is higher than the voltage at the second end, the voltage across the first resistor R1 will be neutralized until the voltage across the first resistor R1 is equal; since the voltage of the liquid crystal capacitor Clc has been changing from the end of charging to the completion of neutralization, the liquid crystal has been rotating continuously from the end of charging to the completion of neutralization, and the rotation stops at the position when neutralization is completed and the display is maintained until the next frame to charge this row again.

[0055] like Figure 3 As shown, t1-t3 represents the display duration of one frame. Since the grayscale voltage on the liquid crystal capacitor does not change within one frame, the liquid crystal is always kept at a certain rotation angle, thereby making the display brightness of the sub-pixel unchanged.

[0056] It should be noted that Figure 2 The schematic diagram of the relationship between voltage and brightness matching the pixel circuit in Figure 4As shown, at time t1, it represents the charging stage. The positive grayscale voltage on the liquid crystal capacitor becomes higher than the voltage corresponding to the current rotation angle of the liquid crystal, and the liquid crystal rotates to a brighter angle. Due to voltage neutralization, the voltage on the liquid crystal capacitor gradually approaches the second common voltage. At time t2, the reduced grayscale voltage is equal to the voltage corresponding to the increased rotation angle. Then, the grayscale voltage of the liquid crystal capacitor continues to be neutralized toward the first resistor, and the voltage becomes lower than the voltage corresponding to the rotation angle of the liquid crystal. Then, the liquid crystal rotates to a darker angle. Then, at time t23, the grayscale voltage is completely neutralized, and the voltage of the liquid crystal capacitor stays at a fixed voltage. Then, the liquid crystal also rotates to the corresponding angle and stops. Time t3 represents the charging stage of a new frame of display, and the subsequent working principle is the same as the previous frame. Among them, Figure 4 The solid line in represents the voltage on the liquid crystal capacitor Clc, and the dotted line represents the second common voltage Avcom.

[0057] through Figure 4 and Figure 3 By comparison, it can be seen that the present embodiment splits each frame of the image in time, so that the display brightness is different at different times within a frame, and the grayscale brightness of a frame is the average integral effect of a frame of time. Therefore, when the display brightness presented at the end of a frame of the image remains unchanged, since the liquid crystal molecules rotate continuously within a frame, the emitted light can have different emission angles, thereby greatly improving the display viewing angle.

[0058] Furthermore, since the pixel circuit provided in this embodiment does not require any additional scan line or data line routing, the aperture ratio of the display screen can be increased, thereby increasing the transmittance of the display screen, and the driving cost can also be reduced.

[0059] In this embodiment, the voltage neutralization unit performs voltage neutralization based on the following relationship:

[0060]

[0061] in, Indicates the voltage drop value of the liquid crystal capacitor, Indicates the voltage rise value of the first neutralizing capacitor or the second neutralizing capacitor, Represents the grayscale voltage, represents the second common voltage, Indicates the capacitance parameter of liquid crystal capacitor, represents the capacitance parameter of the first neutralizing capacitor or the second neutralizing capacitor; wherein, Indicates the voltage neutralization stop point, that is Figure 4 The voltage point corresponding to time t23 can be calculated based on The relationship between the liquid crystal capacitor and the first neutralizing capacitor can be adjusted to determine the final stop position of the liquid crystal rotation. The dynamic grayscale sacrifices brightness, and the backlight brightness needs to be increased to display, so the liquid crystal rotation finally stops, which can determine the degree of sacrifice. Because the display screen now supports variable frequency display, when the refresh rate is high, the liquid crystal rotation is expected to increase the viewing angle, but if the display is low refresh, the frame time is long, and there is a lower limit of the grayscale voltage, so the brightness will not be sacrificed too much, so the capacitor voltage neutralization method is used. In addition, the first resistor value can be adjusted according to product requirements, and then the liquid crystal rotation speed can be adjusted to control the ratio of the liquid crystal rotation time to the non-rotation time within a frame.

[0062] Embodiment 3

[0063] In another embodiment of the present application, Figure 5 As shown, the reset unit 120 includes:

[0064] The second switch tube T2, the control end of the second switch tube T2 is connected to the first scan line 300, the first end of the second switch tube T2 is connected to the third end of the voltage neutralization unit 110, and the second end of the second switch tube T2 is connected to the second common electrode AVcom.

[0065] The voltage neutralization unit 110 includes: a third switch tube T3, and a second neutralization capacitor Cz2; the control end of the third switch tube T3 is connected to the second scan line 400 providing the second scan voltage, the first end of the third switch tube T3 is connected to the first end of the liquid crystal capacitor Clc, the second end of the third switch tube T3 is respectively connected to the first end of the second neutralization capacitor Cz2 and the first end of the reset unit 120, and the second end of the second neutralization capacitor Cz2 is connected to the second common electrode AVcom.

[0066] It should be noted that, taking the first scan line Gn in the nth row and the second scan line Kn in the nth row as an example, the working principle of the pixel circuit provided in this embodiment is:

[0067] First, Gn outputs a high level to turn on the first switch tube T1 and the second switch tube T2 at the same time, and Kn outputs a low level to turn off the third switch tube T3. The liquid crystal capacitor Clc is charged to the grayscale voltage level (i.e., the data signal output by the data line) through the first switch tube T1, and the second neutralization capacitor Cz2 is charged to the second common voltage through the second switch tube T2. The purpose of charging the second neutralization capacitor Cz2 to the second common voltage at this time is to reset the voltage of the second neutralization capacitor Cz2 to prevent the display of this frame from being affected by the voltage left after the neutralization of the previous frame.

[0068] Then, when Gn outputs a low level, the charging time of the current row ends and the normal picture begins to be displayed. At the same time, within the remaining scanning time of several thousand rows in a frame, the time when Kn outputs a high level can be selected; when Kn outputs a high level, the third switch tube T3 is turned on, and the liquid crystal capacitor Clc and the second neutralization capacitor Cz2 perform voltage neutralization, so that the voltage of the liquid crystal capacitor Clc is quickly reduced to the neutralization voltage, and then Kn outputs a low level, so that the voltage of the liquid crystal capacitor Clc remains at the neutralization voltage; since the voltage of the liquid crystal capacitor Clc changes from the end of charging to the completion of neutralization, the liquid crystal also changes in rotation angle from the end of charging to the completion of neutralization, and the rotation stops at the position when neutralization is completed and the display is maintained until the next frame to charge this row again.

[0069] like Figure 6 As shown, time t1 represents the charging stage, the positive grayscale voltage on the liquid crystal capacitor Clc becomes higher than the voltage corresponding to the current rotation angle of the liquid crystal, then the liquid crystal rotates to the brightening angle and stays at the rotation angle; time t2 is the stage where the second scanning line 400 outputs a high level, at this time, the third switch tube T3 is turned on, so that the liquid crystal capacitor Clc and the second neutralization capacitor Cz2 achieve voltage neutralization, thereby reducing the voltage of the liquid crystal capacitor Clc to the neutralization voltage, and the neutralization voltage is lower than the voltage corresponding to the current rotation angle of the liquid crystal, then the liquid crystal rotates to the darkening angle and stays at the rotation angle until time t3, and time t3 represents the charging stage of a new frame of display, and the subsequent working principle is the same as the previous frame.

[0070] It should be noted that Figure 6 The display brightness shown is that the voltage corresponding to the liquid crystal rotation angle when the third switch tube T3 is turned on is greater than the neutralization voltage, so at the moment t2 when the voltage suddenly changes, the liquid crystal rotates toward the darkened neutralization voltage angle; there is another situation that starting from the moment t1, when the liquid crystal rotates from the rotation angle of the previous frame to the angle corresponding to the grayscale voltage of the current frame, the third switch tube T3 is turned on before it rotates to the angle corresponding to the neutralization voltage. At this time, the liquid crystal stops rotating after reaching the angle corresponding to the neutralization voltage, and rotates again after the charging moment of the next frame, which can also achieve the effect of improving the display viewing angle; therefore, the opening time of the third switch tube T3 can be adjusted according to the actual display effect.

[0071] It can be seen that this embodiment divides each frame of the picture in time, so that the same sub-pixel displays two brightness levels in one frame, and the grayscale brightness of one frame is the average integral effect of one frame time. Therefore, when the display brightness finally presented in one frame of the picture remains unchanged, the viewing angle of the display screen can be increased because the liquid crystal molecules have two rotation angles in one frame; compared with the 8-domain pixel structure, the viewing angle of the display screen is improved while the transmittance is not reduced.

[0072] In another embodiment of the present application, the second scan line controls the third switch tube to be not fully opened, and the different voltages output by the second scan line make the third switch tube have different internal resistance values, so that the third switch tube is used as a variable resistor that can be adjusted at any time, so as to achieve the purpose of real-time adjustment of the liquid crystal rotation speed according to the actual application scenario.

[0073] Embodiment 4

[0074] In another embodiment of the present application, Figure 7 As shown, the reset unit 120 includes:

[0075] The second switch tube T2, the control end of the second switch tube T2 is connected to the first scan line 300, the first end of the second switch tube T2 is connected to the third end of the voltage neutralization unit 110, and the second end of the second switch tube T2 is connected to the second common electrode AVcom.

[0076] The voltage neutralization unit 110 includes: a third switch tube T3, a second resistor R2 and a second neutralization capacitor Cz2; the control end of the third switch tube T3 is connected to the second scan line 400 providing a second scan voltage, the first end of the third switch tube T3 is connected to the first end of the liquid crystal capacitor Clc, the second end of the third switch tube T3 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is respectively connected to the first end of the second neutralization capacitor Cz2 and the first end of the second switch tube T2, and the second end of the second neutralization capacitor Cz2 is connected to the second common electrode AVcom.

[0077] It should be noted that, taking the first scan line Gn in the nth row and the second scan line Kn in the nth row as an example, the working principle of the pixel circuit provided in this embodiment is:

[0078] First, Gn outputs a high level and turns on the first switch tube T1 and the second switch tube T2 at the same time, and charges the liquid crystal capacitor Clc to the grayscale voltage level (i.e., the data signal output by the data line) through the first switch tube T1, and charges the second neutralization capacitor Cz2 to the second common voltage through the second switch tube T2; at this time, the purpose of charging the second neutralization capacitor Cz2 to the second common voltage is to reset the voltage of the second neutralization capacitor Cz2 to prevent the display of this frame from being affected by the voltage left after the neutralization of the previous frame.

[0079] Then, when Gn outputs a low level, the charging time of the current row ends and the normal picture begins to be displayed; at the same time, the second scanning line Kn outputs a voltage to control the third switch tube T3 to be in a state between fully open and closed, so that the internal resistance of the third switch tube T3 is equivalent to a variable resistor. In the remaining scanning time of several thousand rows of a frame, the liquid crystal capacitor Clc will neutralize the voltage through the internal resistance of the third switch tube T3, the second resistor R2 and the second neutralization capacitor Cz2. Since the voltage of the first end of the third switch tube T3 is higher than the voltage of the second end of the second resistor R2, the voltage of the first end of the third switch tube T3 will be neutralized toward the second resistor R2 until the voltage of the first end of the third switch tube T3 is equal to the voltage of the second end of the second resistor R2; since the voltage of the liquid crystal capacitor Clc is constantly changing from the end of charging to the completion of neutralization, the liquid crystal is also constantly rotating from the end of charging to the completion of neutralization, and the rotation stops at the position when the neutralization is completed to maintain the display until the next frame charges this row again.

[0080] It can be seen from this that this embodiment uses a voltage neutralization unit composed of a third switch tube, a second resistor and a second neutralization capacitor, and uses the third switch tube as a variable resistor that can be adjusted at any time. The speed of voltage neutralization can be adjusted at any time, thereby achieving the purpose of adjusting the liquid crystal rotation speed in real time according to the actual application scenario.

[0081] In another embodiment of the present application, the pixel circuit 100 further includes: a storage capacitor Cst, a first end of the storage capacitor Cst is connected to a first end of the liquid crystal capacitor Clc, and a second end of the storage capacitor Cst is connected to the second common electrode AVcom.

[0082] It should be noted that the storage capacitor Cst is also charged while the liquid crystal capacitor Clc is charged. The storage capacitor Cst is used to maintain the voltage value on one side of the liquid crystal capacitor Clc after the data signal transmitted on the data line stops charging the liquid crystal capacitor Clc, thereby preventing the liquid crystal capacitor Clc from leaking.

[0083] The present application provides a pixel driving method, which specifically includes the following embodiments:

[0084] In one embodiment, if Figure 8 As shown, the pixel driving method specifically includes the following steps:

[0085] Step S110, in the charging stage, the first scanning line outputs the first scanning voltage to turn on the first switch tube, and charges the liquid crystal capacitor to the grayscale voltage output by the data line, and at the same time, the voltage in the voltage neutralization unit is reset through the reset unit;

[0086] Step S120: In the display stage, the first scan line stops outputting the first scan voltage to turn off the first switch tube, and the voltage in the liquid crystal capacitor is neutralized by the voltage neutralization unit until the voltage in the voltage neutralization unit is equal to the voltage in the liquid crystal capacitor.

[0087] It should be noted that the first scanning voltage is a voltage that can turn on the first switch tube. When the first scanning line outputs the first scanning voltage, it is a charging stage, and the grayscale voltage output by the data line is used to charge the liquid crystal capacitor; at the same time, the voltage in the voltage neutralization unit is reset by the reset unit to prevent the residual voltage in the voltage neutralization unit from affecting the subsequent voltage neutralization; when the first scanning line stops outputting the first scanning voltage, it enters the display stage. When the liquid crystal capacitor stops charging, the voltage on the liquid crystal capacitor becomes higher than the voltage corresponding to the next rotation angle of the liquid crystal, and the liquid crystal rotates to a brightening angle; at the same time, the liquid crystal capacitor forms a loop with the voltage neutralization unit, and the charge stored in the liquid crystal capacitor is transferred to the voltage neutralization unit until the voltage in the liquid crystal capacitor is equal to that in the voltage neutralization unit. At this stage, the liquid crystal rotates to a darkening angle as the voltage of the liquid crystal capacitor gradually decreases, until it stops rotating at the moment when the voltage neutralization is completed; at the beginning of the next charging stage, a frame of display is completed.

[0088] In this embodiment, the reset unit may be a second switch tube; wherein the control end of the second switch tube is connected to the first scan line, the first end of the second switch tube is connected to the third end of the voltage neutralization unit, and the second end of the second switch tube is connected to the second common electrode;

[0089] In this embodiment, the voltage neutralization unit can be a first resistor and a first neutralization capacitor; wherein the first end of the first resistor is connected to the first end of the liquid crystal capacitor, the second end of the first resistor is respectively connected to the first end of the first neutralization capacitor and the first end of the reset unit, and the second end of the first neutralization capacitor is connected to the second common electrode.

[0090] In another embodiment, when the voltage neutralization unit in the pixel circuit includes: a third switch tube, and a second neutralization capacitor, wherein the control end of the third switch tube is connected to the second scanning line providing the second scanning voltage, the first end of the third switch tube is connected to the first end of the liquid crystal capacitor, the second end of the third switch tube is respectively connected to the first end of the second neutralization capacitor and the first end of the reset unit, and the second end of the second neutralization capacitor is connected to the second common electrode; Fig. 9 As shown, the pixel driving method specifically includes the following steps:

[0091] Step S210, in the charging stage, the first scan line outputs the first scan voltage to turn on the first switch tube, the second scan line stops outputting the second scan voltage to turn off the third switch tube, the liquid crystal capacitor is charged to the grayscale voltage output by the data line, and the voltage in the voltage neutralization unit is reset by the reset unit;

[0092] Step S220, in the display stage, the first scan line stops outputting the first scan voltage to turn on the first switch tube, and within a preset time after the first scan line stops outputting the first scan voltage, the second scan line outputs the second scan voltage to turn on the third switch tube, and the voltage in the liquid crystal capacitor is neutralized by the second neutralization capacitor until the voltage in the second neutralization capacitor is equal to that in the liquid crystal capacitor.

[0093] It should be noted that, first, the first scan line outputs the first scan voltage to turn on the first switch tube, and the second scan line turns off the third switch tube, and the liquid crystal capacitor is charged to the grayscale voltage through the first switch tube; then, after the first scan line turns off the first switch tube, the charging time of the current row ends and the normal picture begins to be displayed, and a period of time after the first scan line turns off the first switch tube, the second scan line turns on the third switch tube, and the liquid crystal capacitor and the second neutralization capacitor perform voltage neutralization, so that the voltage of the liquid crystal capacitor is quickly reduced to the neutralization voltage, and then the third switch tube is turned off, so that the voltage of the liquid crystal capacitor remains at the neutralization voltage; since the voltage of the liquid crystal capacitor changes from the end of charging to the completion of neutralization, the liquid crystal also changes in rotation angle from the end of charging to the completion of neutralization, and the rotation stops at the position when neutralization is completed and the display is maintained until the next frame when the row is charged again.

[0094] The pixel driving method provided in the present application divides each frame into stages in time so that the display brightness at different times within a frame is different, and the grayscale brightness of a frame is the average integral effect of the frame time. Therefore, when the display brightness presented at the end of a frame remains unchanged, the liquid crystal molecules rotate within a frame, resulting in different output angles of the emitted light, which greatly improves the display viewing angle.

[0095] The present application provides a display panel, which includes a plurality of first scan lines providing a first scan voltage and a plurality of data lines providing a grayscale voltage. The display panel also includes the pixel circuit of the above embodiment.

[0096] Furthermore, when the voltage neutralization unit includes a third switch tube, the display panel further includes a plurality of second scan lines; wherein the control end of the third switch tube is connected to the second scan line.

[0097] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third" may explicitly or implicitly include one or more of the feature. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0098] In the description of this specification, the description with reference to the terms "some embodiments", "exemplarily", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0099] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. Therefore, any changes or modifications made in accordance with the claims and description of the present application should fall within the scope of the patent of this application.

Claims

1. A pixel circuit, characterized in that: The pixel circuit comprises: A first switch tube, a liquid crystal capacitor, a voltage neutralization unit and a reset unit; The control end of the first switch tube is connected to a first scan line providing a first scan voltage, the first end of the first switch tube is connected to a data line providing a grayscale voltage, the second end of the first switch tube is connected to a first end of the liquid crystal capacitor, and the second end of the liquid crystal capacitor is connected to a first common electrode providing a first common voltage, so that the liquid crystal molecules in the liquid crystal capacitor rotate multiple times within one frame; The first end of the voltage neutralization unit is connected to the first end of the liquid crystal capacitor, and the second end of the voltage neutralization unit is connected to the second common electrode providing the second common voltage, so as to neutralize the voltage in the liquid crystal capacitor after charging is completed; The control end of the reset unit is connected to the first scan line, the first end of the reset unit is connected to the third end of the voltage neutralization unit, the second end of the reset unit is connected to the second common electrode, and the reset unit is used to reset the voltage in the voltage neutralization unit during the charging stage; The voltage neutralization unit includes: a first resistor and a first neutralization capacitor, wherein a first end of the first resistor is connected to a first end of the liquid crystal capacitor, a second end of the first resistor is respectively connected to a first end of the first neutralization capacitor and a first end of the reset unit, and a second end of the first neutralization capacitor is connected to the second common electrode; Or, the voltage neutralization unit includes: a third switch tube, and a second neutralization capacitor; the control end of the third switch tube is connected to the second scan line providing the second scan voltage, the first end of the third switch tube is connected to the first end of the liquid crystal capacitor, the second end of the third switch tube is respectively connected to the first end of the second neutralization capacitor and the first end of the reset unit, and the second end of the second neutralization capacitor is connected to the second common electrode; The voltage neutralization unit performs voltage neutralization based on the following relationship: in, Indicates the voltage drop value of the liquid crystal capacitor, Indicates the voltage rise value of the first neutralizing capacitor or the second neutralizing capacitor, Represents the grayscale voltage, represents the second common voltage, Indicates the capacitance parameter of liquid crystal capacitor, Indicates the capacitance parameter of the first neutralization capacitor or the second neutralization capacitor.

2. The pixel circuit according to claim 1, characterized in that: The reset unit comprises: A second switch tube, wherein a control end of the second switch tube is connected to the first scan line, a first end of the second switch tube is connected to the third end of the voltage neutralization unit, and a second end of the second switch tube is connected to the second common electrode.

3. The pixel circuit according to claim 1, characterized in that: The voltage neutralization unit further includes: A second resistor, wherein a first end of the second resistor is connected to a second end of the third switch tube, and a second end of the second resistor is respectively connected to a first end of the second neutralization capacitor and a first end of the reset unit.

4. A pixel driving method, applied to the pixel circuit according to claim 1, characterized in that: The driving method comprises: In the charging stage, the first scanning line outputs the first scanning voltage to turn on the first switch tube, charging the liquid crystal capacitor to the grayscale voltage output by the data line, and at the same time resetting the voltage in the voltage neutralization unit through the reset unit; In the display stage, the first scan line stops outputting the first scan voltage to turn off the first switch tube, and the voltage in the liquid crystal capacitor is neutralized by the voltage neutralization unit until the voltage in the voltage neutralization unit is equal to the voltage in the liquid crystal capacitor.

5. The pixel driving method according to claim 4, characterized in that: The voltage neutralization unit includes: a third switch tube and a second neutralization capacitor; The control end of the third switch tube is connected to the second scan line providing the second scan voltage, the first end of the third switch tube is connected to the first end of the liquid crystal capacitor, the second end of the third switch tube is respectively connected to the first end of the second neutralization capacitor and the first end of the reset unit, and the second end of the second neutralization capacitor is connected to the second common electrode; The driving method further comprises: In the charging stage, the second scanning line stops outputting the second scanning voltage to turn off the third switch tube; In the display stage, within a preset time after the first scan line stops outputting the first scan voltage, the second scan line outputs the second scan voltage to turn on the third switch tube, and the voltage in the liquid crystal capacitor is neutralized by the second neutralization capacitor until the voltage in the second neutralization capacitor is equal to that in the liquid crystal capacitor.

6. A display panel, comprising a plurality of first scan lines providing a first scan voltage and a plurality of data lines providing a grayscale voltage, wherein: The display panel further comprises a pixel circuit as claimed in any one of claims 1 to 3.

7. The display panel according to claim 6, characterized in that: When the voltage neutralization unit includes a third switch tube, the display panel further includes a plurality of second scan lines; wherein the control end of the third switch tube is connected to the second scan line.

Images