CN107797343B - Liquid crystal display device with switchable viewing angle and driving method thereof - Google Patents
Liquid crystal display device with switchable viewing angle and driving method thereof Download PDFInfo
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- CN107797343B CN107797343B CN201711091555.1A CN201711091555A CN107797343B CN 107797343 B CN107797343 B CN 107797343B CN 201711091555 A CN201711091555 A CN 201711091555A CN 107797343 B CN107797343 B CN 107797343B
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1343—Electrodes
- G02F1/134309—Electrodes characterised by their geometrical arrangement
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/1323—Arrangements for providing a switchable viewing angle
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/13306—Circuit arrangements or driving methods for the control of single liquid crystal cells
Abstract
A liquid crystal display device with switchable visual angles comprises a first substrate, a second substrate and a liquid crystal layer, wherein a visual angle control electrode is arranged on the first substrate, a common electrode is arranged on the second substrate, a plurality of sub-pixels are limited by scanning lines and data lines on the second substrate, a thin film transistor and a pixel electrode are arranged in each sub-pixel, the pixel electrode comprises at least one first electrode part and at least one second electrode part connected with the first electrode part, the first electrode part comprises a plurality of first electrode strips, the second electrode part comprises a plurality of second electrode strips, and the first electrode strips are perpendicular to the second electrode strips. By applying a visual angle control voltage on the visual angle control electrode, a voltage difference is generated between the visual angle control electrode and the common electrode, a vertical electric field is formed in a region of the corresponding sub-pixel between the two substrates, liquid crystal molecules are deflected under the action of the vertical electric field, and the liquid crystal display device is switched between a wide visual angle and an omnibearing narrow visual angle.
Description
Technical Field
The present invention relates to the field of display technologies, and in particular, to a liquid crystal display device with switchable viewing angles and a driving method thereof.
Background
A Liquid Crystal Display (LCD) has advantages of good picture quality, small size, light weight, low driving voltage, low power consumption, no radiation, and relatively low manufacturing cost, and is dominant in the field of flat panel displays.
With the continuous progress of the liquid crystal display technology, the viewing angle of the display has been widened from about 120 ° to over 160 °, and people want to effectively protect business confidentiality and personal privacy while enjoying visual experience brought by a large viewing angle, so as to avoid business loss or embarrassment caused by the leakage of screen information.
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. Referring to fig. 1 and 2, the lcd device includes a first substrate 11, a second substrate 12, and a liquid crystal layer 13 disposed between the first substrate 11 and the second substrate 12, wherein a viewing angle control electrode 111 is disposed on the first substrate 11. As shown in fig. 1, in the wide viewing angle display, the viewing angle control electrode 111 on the first substrate 11 does not apply a voltage, and the liquid crystal display device realizes the wide viewing angle display. As shown in fig. 2, when a narrow viewing angle display is required, the viewing angle control electrode 111 on the first substrate 11 is applied with a voltage, the liquid crystal molecules in the liquid crystal layer 13 tilt up due to an electric field in a vertical direction (as shown by an arrow E in the figure) while rotating horizontally, and the contrast of the liquid crystal display device is reduced due to light leakage, thereby finally realizing a narrow viewing angle. However, this method can only switch the wide and narrow viewing angles in the left-right direction, and cannot simultaneously switch the wide and narrow viewing angles in the left-right direction and/or the up-down direction.
Disclosure of Invention
The invention aims to provide a liquid crystal display device, which solves the problem that the conventional liquid crystal display device can only realize the switching of wide and narrow visual angles in the left and right directions.
The technical problem to be solved by the invention is realized by adopting the following technical scheme.
The invention provides a liquid crystal display device with switchable visual angles, which comprises a first substrate, a second substrate arranged opposite to the first substrate and a liquid crystal layer positioned between the first substrate and the second substrate, wherein a visual angle control electrode is arranged on the first substrate, a common electrode is arranged on the second substrate, a plurality of sub-pixels are formed on the second substrate in a limited mode through scanning lines and data lines, a thin film transistor and a pixel electrode are arranged in each sub-pixel, the pixel electrode is connected with the corresponding scanning lines and the corresponding data lines through the thin film transistor, the pixel electrode comprises at least one first electrode part and at least one second electrode part connected with the first electrode part, the first electrode part comprises a plurality of first electrode strips, the second electrode part comprises a plurality of second electrode strips, and the plurality of first electrode strips are perpendicular to the plurality of second electrode strips.
Further, the pixel electrode comprises a first electrode part and a second electrode part connected with the first electrode part, the first electrode part is correspondingly arranged on the upper half part of each sub-pixel, and the second electrode part is correspondingly arranged on the lower half part of each sub-pixel.
Furthermore, the pixel electrode comprises a first electrode part and two second electrode parts connected with the first electrode part, the first electrode part is correspondingly arranged in the middle of each sub-pixel, and the two second electrode parts are respectively correspondingly arranged at the upper part and the lower part of each sub-pixel.
Further, the plurality of first electrode stripes extend along the data line direction, and the plurality of second electrode stripes extend along the scan line direction.
Further, the liquid crystal molecules in the liquid crystal layer are positive liquid crystal molecules, the alignment direction of the positive liquid crystal molecules corresponding to the first electrode portion extends along the direction of the first electrode bars, and the alignment direction of the positive liquid crystal molecules corresponding to the second electrode portion extends along the direction of the second electrode bars.
Further, the liquid crystal molecules in the liquid crystal layer are negative liquid crystal molecules, the alignment direction of the negative liquid crystal molecules corresponding to each first electrode portion extends in a direction vertical to the first electrode strips, and the alignment direction of the negative liquid crystal molecules corresponding to each second electrode portion extends in a direction vertical to the second electrode strips.
Further, corresponding to each first electrode portion, the alignment direction on the first substrate is parallel or antiparallel to the alignment direction on the second substrate; the alignment direction on the first substrate is parallel or antiparallel to the alignment direction on the second substrate corresponding to each of the second electrode portions.
A driving method of a liquid crystal display device switchable in viewing angle as described above, the driving method comprising:
in a first visual angle mode, applying a common voltage to the common electrode, and applying a first voltage with a smaller amplitude relative to the common voltage to the visual angle control electrode, so that the voltage difference between the visual angle control electrode and the common electrode is smaller than a first preset value;
in a second viewing angle mode, a common voltage is applied to the common electrode, a second voltage with a larger amplitude than the common voltage is applied to the viewing angle control electrode, and the voltage difference between the viewing angle control electrode and the common electrode is larger than a second preset value, wherein the second preset value is larger than or equal to the first preset value.
Further, in the first viewing angle mode, the common voltage applied to the common electrode and the first voltage applied to the viewing angle control electrode are both dc voltages and the voltage difference between the two voltages is zero.
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.
The invention provides a liquid crystal display device with switchable visual angles, wherein a visual angle control electrode for controlling the visual angle is arranged on a first substrate, a thin film transistor and a pixel electrode are arranged in each sub-pixel, each pixel electrode comprises at least one first electrode part and at least one second electrode part, a plurality of first electrode strips of each electrode part are vertical to a plurality of second electrode strips of each second electrode part, a visual angle control voltage is applied to the visual angle control electrode, so that a voltage difference is generated between the visual angle control electrode and a common electrode, a vertical electric field is formed in the corresponding area of a plurality of sub-pixels between two substrates at the same time, liquid crystal molecules in a liquid crystal layer are deflected under the action of the vertical electric field, and the visual angle adjustment of the liquid crystal display device in the left-right direction and the up-down direction is realized.
Drawings
Fig. 1 is a schematic cross-sectional view of a conventional liquid crystal display device under wide viewing angle display.
Fig. 2 is a schematic cross-sectional view of the liquid crystal display device of fig. 1 under a narrow viewing angle display.
FIG. 3 is a schematic plan view of a liquid crystal display device according to a first embodiment of the present invention.
Fig. 4 is an exploded view of the lcd device shown in fig. 3.
FIG. 5 is a schematic plan view of the LCD device in FIG. 3 in a black state.
Fig. 6a to 6c are schematic diagrams illustrating the arrangement of positive liquid crystal molecules of the liquid crystal display device in fig. 3 under different voltages.
FIG. 7 is a schematic plan view of a liquid crystal display device according to a second embodiment of the present invention.
FIG. 8 is a schematic plan view of a liquid crystal display device in a black state according to a third embodiment of the present invention.
Fig. 9a to 9c are schematic diagrams of the arrangement of negative liquid crystal molecules of the liquid crystal display device in fig. 8 under different voltages.
FIG. 10 is a schematic plan view of a liquid crystal display device 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. 3 is a schematic plan view of a liquid crystal display device according to a first embodiment of the invention, and fig. 4 is a schematic exploded view of the liquid crystal display device in fig. 3. Referring to fig. 3 to 4, the lcd device includes a first substrate 21, a second substrate 22 disposed opposite to the first substrate 21, and a liquid crystal layer 23 disposed between the first substrate 21 and the second substrate 22.
The liquid crystal display device according to the present embodiment is suitable for use in a liquid crystal display device of an in-plane switching (IPS) mode, a Fringe Field Switching (FFS) mode, or the like, in which the common electrode and the pixel electrode are formed on the same substrate (that is, a thin film transistor array substrate), and when an electric field for display is applied between the common electrode and the pixel electrode, liquid crystal molecules rotate in a plane substantially parallel to the substrate to obtain a wide viewing angle. In this embodiment, the liquid crystal display device will be described by taking a Fringe Field Switching (FFS) mode as an example.
The first substrate 21 is, for example, a color filter substrate, and the second substrate 22 is, for example, a thin film transistor array substrate. The first substrate 21 is provided with a first polarizer 211 at a side facing away from the liquid crystal layer 23, the second substrate 22 is provided with a second polarizer 221 at a side facing away from the liquid crystal layer 23, and a transmission axis X1 of the first polarizer 211 is perpendicular to a transmission axis X2 of the second polarizer 221.
Fig. 5 is a schematic plan view of the liquid crystal display device in fig. 3 in a black state, and fig. 6a to 6c are schematic arrangement diagrams of positive liquid crystal molecules of the liquid crystal display device in fig. 3 under different voltages. Referring to fig. 5 and fig. 6a to 6c, the first substrate 21 has a viewing angle control electrode 212 on a side facing the liquid crystal layer 23, and the second substrate 22 has a scan line 222, a data line 223, a Thin Film Transistor (TFT)224, a common electrode 225(common electrode), an insulating layer 226, and a pixel electrode 227(pixel electrode) on a side facing the liquid crystal layer 23.
Wherein the plurality of scan lines 222 and the plurality of data lines 223 cross each other to define a plurality of sub-pixels SP (sub-pixels) distributed in an array. In this embodiment, each sub-pixel SP is, for example, a red (R), green (G), and blue (B) sub-pixel, and a plurality of adjacent sub-pixels SP form a pixel p (pixel) for display. For example, one pixel P may include three sub-pixels SP of red (R), green (G), and blue (B), but the present invention is not limited thereto.
Each sub-pixel SP is provided with a thin film transistor 224 and a pixel electrode 227, the pixel electrode 227 is connected with the corresponding scan line 222 and data line 223 through the thin film transistor 224, and the pixel electrode 227 comprises at least one first electrode portion 227a and at least one second electrode portion 227b connected with the first electrode portion 227 a.
In the present embodiment, taking as an example that each pixel electrode 227 includes one first electrode portion 227a and one second electrode portion 227b, the first electrode portion 227a is correspondingly disposed at the upper half portion of each sub-pixel SP, the second electrode portion 227b is correspondingly disposed at the lower half portion of each sub-pixel SP, and the thin film transistor 224 is electrically connected to the first electrode portion 227a, and in other embodiments, the thin film transistor 224 may be electrically connected to the second electrode portion 227 b.
Specifically, the thin film transistor 224 is located near a position where the scan line 222 and the data line 223 cross. The thin film transistor 224 is electrically connected to the corresponding scan line 222, data line 223 and first electrode portion 227 a. Each tft 224 includes a gate electrode, a semiconductor layer, a source electrode and a drain electrode (not shown), wherein the gate electrode is electrically connected to the corresponding scan line 222, the source electrode and the drain electrode are spaced apart from each other and are in contact with the semiconductor layer, one of the source electrode and the drain electrode is electrically connected to the corresponding data line 223, one of the source electrode and the drain electrode is electrically connected to the corresponding first electrode portion 227a, for example, the source electrode is electrically connected to the corresponding data line 223, and the drain electrode is electrically connected to the corresponding first electrode portion 227 a.
The first electrode portion 227a includes a plurality of first electrode bars 2271 spaced apart from each other, and a first slit 2274 is formed between adjacent first electrode bars 2271. The second electrode portion 227b includes a plurality of second electrode bars 2272 spaced apart from each other, and a second slit 2275 is formed between adjacent second pixel electrode bars 2272. The first electrode portion 227a and the second electrode portion 227b are electrically connected, that is, the first electrode portion 227a and the second electrode portion 227b receive the same data voltage signal for displaying at every moment.
Further, the plurality of first electrode strips 2271 and the plurality of second electrode strips 2272 are perpendicular to each other. In this embodiment, the plurality of first pixel electrode strips 2271 extend along the data line 223, and the plurality of second pixel electrode strips 2272 extend along the scan line 222.
Referring to fig. 3 and 4, in the present embodiment, the viewing angle control electrode 212 may be a planar electrode, and the sub-pixels SP are respectively arranged in a row along the direction of the scan line 222 and the data line 223.
The viewing angle control electrode 212, the common electrode 225 and the pixel electrode 227 can be made of transparent conductive materials such as Indium Tin Oxide (ITO) and Indium Zinc Oxide (IZO) as transparent electrodes. The viewing angle control electrode 212 is used to control the viewing angle switching. The common electrode 225 is used to apply a common voltage (Vcom) for picture display. The pixel electrode 227 is used for receiving a data signal to control the display of a picture.
In this embodiment, the pixel electrode 227 is located above the common electrode 225, and the insulating layer 226 is disposed therebetween, but the invention is not limited thereto, and in other embodiments, the pixel electrode 227 may also be located below the common electrode 225. In addition, when the liquid crystal display device employs an in-plane switching mode (IPS), the common electrode 225 and the pixel electrode 227 may also be located in the same layer and insulated and spaced apart from each other, for example, the common electrode 225 and the pixel electrode 227 may be respectively made into a comb-like structure having a plurality of electrode stripes and inserted and fitted to each other.
Liquid crystal molecules are generally classified into positive liquid crystal molecules and negative liquid crystal molecules. In this embodiment, the liquid crystal molecules in the liquid crystal layer 23 are preferably positive liquid crystal molecules, and the positive liquid crystal molecules have the advantage of fast response. The alignment direction of the position on the first substrate 21 corresponding to each first electrode portion 227a is a1, the alignment direction of the position on the second substrate 22 corresponding to each first electrode portion 227a is B1, the alignment direction of the position on the first substrate 21 corresponding to each second electrode portion 227B is a2, and the alignment direction of the position on the second substrate 22 corresponding to each second electrode portion 227B is B2. In the present embodiment, the alignment directions a1 and B1 of the positions corresponding to each of the first electrode portions 227a on the first and second substrates 21 and 22 extend along the direction of the first electrode bar 2271, and the alignment directions a2 and B2 of the positions corresponding to each of the second electrode portions 227B on the first and second substrates 21 and 22 extend along the direction of the second electrode bar 2272. The liquid crystal molecules in the liquid crystal layer 23 are aligned along the alignment directions on the first and second substrates 21 and 22, and the initial alignment directions of the liquid crystal molecules within the first and second electrode portions 227a and 227b are perpendicular to each other.
The first substrate 21 and the second substrate 22 may be aligned by photo-alignment, and the photo-alignment may be achieved by using a mask or the like to align the first electrode portion 227a and the second electrode portion 227 b.
Further, the alignment direction a1 on the first substrate 21 is parallel or antiparallel (antiparallel in the present embodiment) to the alignment direction B1 on the second substrate 22 corresponding to each of the first electrode portions 227 a; the alignment direction a2 on the first substrate 21 is parallel or antiparallel (antiparallel in the present embodiment) to the alignment direction B2 on the second substrate 22 corresponding to each of the second electrode portions 227B.
By applying a voltage to the viewing angle control electrode 212, a voltage difference can be generated between the viewing angle control electrode 212 and the common electrode 225, so that the liquid crystal display device can be switched between a wide viewing angle mode and a narrow viewing angle mode, as shown in fig. 6a to 6 c.
Referring to fig. 6a, in an initial state of the lcd device without any voltage applied, the positive liquid crystal molecules in the liquid crystal layer 23 are aligned along the alignment direction and in a lying posture parallel to the first and second substrates 21 and 22, wherein the liquid crystal molecules between the first and second substrates 21 and 22 corresponding to the area of each first electrode portion 227a are aligned along the alignment directions a1 and B1, and the liquid crystal molecules between the first and second substrates 21 and 22 corresponding to the area of each second electrode portion 227B are aligned along the alignment directions a2 and B2. The long axis direction of the positive liquid crystal molecules is substantially parallel to the surfaces of the first and second substrates 21 and 22. In practical applications, the positive liquid crystal molecules in the liquid crystal layer 23 and the first and second substrates 21 and 22 may have a small initial pretilt angle, which may range from less than or equal to 5 degrees, that is: 0 DEG ≦ theta ≦ 5 deg. At this time, since no display voltage is applied to the pixel electrode 227, the liquid crystal molecules do not rotate in a plane parallel to the first substrate 21 and the second substrate 22, and the liquid crystal display device exhibits a black state.
Referring to fig. 6b, when a voltage for display is applied to the pixel electrode 227, and no voltage difference or a small voltage difference (e.g. less than 0.5v) is applied between the viewing angle control electrode 212 and the common electrode 225, the tilt angle of the positive liquid crystal molecules in the liquid crystal layer 23 is almost unchanged and still lies flat, the liquid crystal molecules are driven by the in-plane electric field formed between the pixel electrode 227 (including the first electrode portion 227a and the second electrode portion 227b) and the common electrode 225 on the same substrate (i.e. the second substrate 22) in a conventional in-plane electric field driving manner, and the liquid crystal molecules rotate in a plane parallel to the first substrate 21 and the second substrate 22, so that the liquid crystal molecules realize a wide viewing angle under the action of the strong in-plane electric field.
Referring to fig. 6c, when a voltage for display is applied to the pixel electrode 227 and a voltage difference of a certain magnitude is applied between the viewing angle control electrode 212 and the common electrode 225, since there is a voltage difference between the viewing angle controlling electrode 212 on the first substrate 21 and the common electrode 225 on the second substrate 22, a vertical electric field (as indicated by an arrow E in the figure) is formed between the two substrates 21, 22 in a region corresponding to each first electrode portion 227a and each second electrode portion 227b, since the long axis direction of the positive liquid crystal molecules tends to rotate in a direction parallel to the electric field lines under the action of an electric field, the positive liquid crystal molecules corresponding to each of the first electrode portions 227a and each of the second electrode portions 227b are deflected by the vertical electric field, the inclination angle with the first substrate 21 and the second substrate 22 increases, and the tilt angle is changed from the lying posture to the inclined posture. The positive liquid crystal molecules in each of the first electrode portions 227a and each of the second electrode portions 227b are deflected by the vertical electric field, so that the viewing angle of the liquid crystal display device is reduced in both the left-right direction and the up-down direction, thereby switching the liquid crystal display device to a narrow viewing angle in both the left-right direction and the up-down direction.
In this embodiment, the voltage output to the common electrode 225 is a DC common voltage (i.e., DC Vcom), and the voltage output to the viewing angle control electrode 212 is a periodic alternating voltage that fluctuates up and down around the DC common voltage. The waveform of the ac voltage may be a square wave, a sine wave, a triangular wave, a sawtooth wave, or the like.
In order to apply voltage to the viewing angle control electrode 212 on the first substrate 21, in the peripheral non-display area of the liquid crystal display device, the viewing angle control electrode 212 is electrically conducted from the first substrate 21 to the second substrate 22 through a conductive adhesive (not shown), a driving chip (not shown) provides voltage to the second substrate 22, and the second substrate 22 applies voltage to the viewing angle control electrode 212 of the first substrate 21 through the conductive adhesive.
[ second embodiment ]
FIG. 7 is a schematic plan view of a liquid crystal display device according to a second embodiment of the present invention. Referring to fig. 7, in the present embodiment, the liquid crystal molecules in the liquid crystal layer 23 are negative liquid crystal molecules, each sub-pixel SP includes a thin film transistor 224 and a pixel electrode 227, each pixel electrode 227 includes a first electrode portion 227a and two second electrode portions 227b, the two second electrode portions 227b are both connected to the first electrode portion 227a, the first electrode portion 227a is correspondingly disposed in the middle of each sub-pixel SP, and the two second electrode portions 227b are correspondingly disposed in the upper portion and the lower portion of each sub-pixel SP. The thin film transistor 224 is electrically connected to the second electrode portion 227b, and in other embodiments, the thin film transistor 224 may be electrically connected to the first electrode portion 227 a.
Specifically, the thin film transistor 224 is located near a position where the scan line 222 and the data line 223 cross. The thin film transistor 224 is electrically connected to the corresponding scan line 222, data line 223 and second electrode portion 227 b. Each tft 224 includes a gate electrode, a semiconductor layer, a source electrode and a drain electrode (not shown), wherein the gate electrode is electrically connected to the corresponding scan line 222, the source electrode and the drain electrode are spaced apart from each other and are in contact with the semiconductor layer, one of the source electrode and the drain electrode is electrically connected to the corresponding data line 223, one of the source electrode and the drain electrode is electrically connected to the corresponding second electrode portion 227b, for example, the source electrode is electrically connected to the corresponding data line 223, and the drain electrode is electrically connected to the corresponding second electrode portion 227 b.
The difference between the present embodiment and the first embodiment is that each pixel electrode 227 includes one first electrode portion 227a and two second electrode portions 227b, and the present embodiment also includes other structures please refer to the first embodiment.
[ third embodiment ]
Fig. 8 is a schematic plane structure of a liquid crystal display device in a black state according to a third embodiment of the present invention, and fig. 9a to 9c are schematic arrangement diagrams of negative liquid crystal molecules of the liquid crystal display device in fig. 8 under different voltages. Please refer to fig. 8 and fig. 9a to 9c, each sub-pixel SP has a thin film transistor 224 and a pixel electrode 227, the pixel electrode 227 is connected to the corresponding scan line 222 and the data line 223 through the thin film transistor 224, and the pixel electrode 227 includes at least one first electrode portion 227a and at least one second electrode portion 227b connected to the first electrode portion 227 a.
In the present embodiment, taking as an example that each pixel electrode 227 includes one first electrode portion 227a and one second electrode portion 227b, the first electrode portion 227a is correspondingly disposed at the upper half portion of each sub-pixel SP, the second electrode portion 227b is correspondingly disposed at the lower half portion of each sub-pixel SP, and the thin film transistor 224 is electrically connected to the first electrode portion 227a, and in other embodiments, the thin film transistor 224 may be electrically connected to the second electrode portion 227 b.
Liquid crystal molecules are generally classified into positive liquid crystal molecules and negative liquid crystal molecules. In this embodiment, the liquid crystal molecules in the liquid crystal layer 23 are negative liquid crystal molecules. The alignment direction of the position on the first substrate 21 corresponding to each first electrode portion 227a is a1, the alignment direction of the position on the second substrate 22 corresponding to each first electrode portion 227a is B1, the alignment direction of the position on the first substrate 21 corresponding to each second electrode portion 227B is a2, and the alignment direction of the position on the second substrate 22 corresponding to each second electrode portion 227B is B2. In this embodiment, the alignment directions a1 and B1 of the positions of the first and second substrates 21 and 22 corresponding to each of the first electrode portions 227a extend perpendicular to the direction of the first electrode bars 2271, and the alignment directions a2 and B2 of the positions of the first and second substrates 21 and 22 corresponding to each of the second electrode portions 227B extend perpendicular to the direction of the second electrode bars 2272. The liquid crystal molecules in the liquid crystal layer 23 are aligned along the alignment directions on the first and second substrates 21 and 22, and the initial alignment directions of the liquid crystal molecules within the first and second electrode portions 227a and 227b are perpendicular to each other.
Please refer to the first embodiment specifically for other components included in this embodiment.
In this embodiment, a voltage difference can be generated between the viewing angle control electrode 212 and the common electrode 225 by applying a voltage to the viewing angle control electrode 212, so that the liquid crystal display device can be switched between a wide viewing angle mode and a narrow viewing angle mode, as shown in fig. 9a to 9 c.
Referring to fig. 9a, when a voltage for display is not applied to the pixel electrode 227 and a voltage difference of a certain magnitude is simultaneously applied between the viewing angle control electrode 212 and the common electrode 225, a vertical electric field (as shown by an arrow E in the figure) is formed between the two substrates 21 and 22 in a region corresponding to each first electrode portion 227a and each second electrode portion 227b, and negative liquid crystal molecules tend to rotate along a direction perpendicular to an electric field line under the action of the electric field, so that the negative liquid crystal molecules are deflected under the action of the vertical electric field, and an inclination angle between the negative liquid crystal molecules and the first substrate 21 and the second substrate 22 is reduced, so that the negative liquid crystal molecules are deflected from an inclined posture to a lying posture. At this time, since no display voltage is applied to the pixel electrode 227, the liquid crystal molecules do not rotate in a plane parallel to the first substrate 21 and the second substrate 22, and the liquid crystal display device displays a black state.
Referring to fig. 9b, when a voltage for display is applied to the pixel electrode 227 and a voltage difference of a certain magnitude is simultaneously applied between the viewing angle control electrode 212 and the common electrode 225, a vertical electric field (as shown by an arrow E in the figure) is formed between the two substrates 21 and 22 in a region corresponding to each of the first electrode portion 227a and each of the second electrode portion 227b, and under the action of the vertical electric field, the negative liquid crystal molecules are deflected, so that the tilt angle between the negative liquid crystal molecules and the first substrate 21 and the second substrate 22 is reduced, and the negative liquid crystal molecules are deflected from the tilted posture to the lying posture. At this time, since a voltage for display is applied to the pixel electrode 227, the negative liquid crystal molecules rotate in a plane parallel to the substrates 21 and 22, and the liquid crystal display device exhibits wide viewing angle display with a reduced light leakage phenomenon and an optimal viewing angle in the oblique viewing direction of the screen.
Referring to fig. 9c, when a voltage for display is applied to the pixel electrode 227, and no voltage difference or a small voltage difference (e.g., less than 0.5v) is applied between the viewing angle control electrode 212 and the common electrode 225, there is no vertical electric field in the corresponding region between the first electrode portion 227a and the second electrode portion 227b between the first substrate 21 and the second substrate 22, and the tilt angle of the negative liquid crystal molecules in the region is almost unchanged and remains in a tilted state. Thereby, the viewing angle of the liquid crystal display device in the left-right direction and the up-down direction is reduced, and the liquid crystal display device is switched to a narrow viewing angle in the left-right direction and the up-down direction.
[ fourth embodiment ]
FIG. 10 is a schematic plan view of a liquid crystal display device according to a fourth embodiment of the present invention. Referring to fig. 10, in the present embodiment, each sub-pixel SP includes a thin film transistor 224 and a pixel electrode 227, each pixel electrode 227 includes a first electrode portion 227a and two second electrode portions 227b, the two second electrode portions 227b are both connected to the first electrode portion 227a, the first electrode portion 227a is correspondingly disposed in the middle of each sub-pixel SP, and the two second electrode portions 227b are correspondingly disposed in the upper portion and the lower portion of each sub-pixel SP. The thin film transistor 224 is electrically connected to the second electrode portion 227b, and in other embodiments, the thin film transistor 224 may be electrically connected to the first electrode portion 227 a.
Specifically, the thin film transistor 224 is located near a position where the scan line 222 and the data line 223 cross. The thin film transistor 224 is electrically connected to the corresponding scan line 222, data line 223 and second electrode portion 227 b.
The difference between the present embodiment and the third embodiment is that each pixel electrode 227 includes one first electrode portion 227a and two second electrode portions 227b, and the present embodiment also includes other structures please refer to the third embodiment.
The invention controls the voltage applied on the visual angle control electrode 212 to generate a certain voltage difference between the first electrode 212 and the common electrode 225, and a vertical electric field is formed between the first substrate 21 and the second substrate 22 corresponding to the area of each first electrode part 227a and each second electrode part 227b, so that liquid crystal molecules in the liquid crystal layer 23 are deflected under the action of the vertical electric field, the light leakage phenomenon is caused to occur, the contrast of a screen is reduced, the visual angles of the liquid crystal display device in the left-right direction and the up-down direction are reduced, and free switching between a wide visual angle and a narrow visual angle in the up-down direction and the left-right direction is realized, and the invention has stronger operation flexibility and convenience.
As used herein, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, including not only those elements listed, but also other elements not expressly listed.
In this document, the terms front, back, upper and lower are used to define the components in the drawings and the positions of the components relative to each other, and are used for clarity and convenience of the technical solution. It is to be understood that the use of the directional terms should not be taken to limit the scope of the claims.
The features of the embodiments and embodiments described herein above may be combined with each other without conflict.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A liquid crystal display device with switchable visual angles, which comprises a first substrate (21), a second substrate (22) arranged opposite to the first substrate (21), and a liquid crystal layer (23) arranged between the first substrate (21) and the second substrate (22), wherein a visual angle control electrode (212) is arranged on the first substrate (21), a common electrode (225) is arranged on the second substrate (22), a plurality of sub-pixels (SP) are defined and formed on the second substrate (22) by scanning lines (222) and data lines (223), a thin film transistor (224) and a pixel electrode (227) are arranged in each sub-pixel (SP), and the pixel electrode (227) is connected with the corresponding scanning lines (222) and data lines (223) through the thin film transistor (224), and is characterized in that the pixel electrode (227) comprises at least one first electrode part (227a) and at least one second electrode part (227) connected with the first electrode part (227a) A portion (227b), the first electrode portion (227a) including a plurality of first electrode bars (2271), the second electrode portion (227b) including a plurality of second electrode bars (2272), the plurality of first electrode bars (2271) and the plurality of second electrode bars (2272) being perpendicular to each other, the first electrode portion (227a) and the second electrode portion (227b) receiving the same data voltage signal for display at every moment.
2. The switchable viewing angle liquid crystal display device of claim 1, wherein the pixel electrode (227) comprises a first electrode portion (227a) and a second electrode portion (227b) connected to the first electrode portion (227a), the first electrode portion (227a) is correspondingly disposed at an upper half portion of each sub-pixel (SP), and the second electrode portion (227b) is correspondingly disposed at a lower half portion of each sub-pixel (SP).
3. The switchable viewing angle liquid crystal display device of claim 1, wherein the pixel electrode (227) comprises a first electrode portion (227a) and two second electrode portions (227b) connected to the first electrode portion (227a), the first electrode portion (227a) is correspondingly disposed at a middle portion of each sub-pixel (SP), and the two second electrode portions (227b) are correspondingly disposed at an upper portion and a lower portion of each sub-pixel (SP), respectively.
4. A liquid crystal display device switchable between viewing angles as claimed in claim 1, wherein the plurality of first electrode stripes (2271) extend along the data line (223) direction, and the plurality of second electrode stripes (2272) extend along the scan line (222) direction.
5. The viewing-angle switchable liquid crystal display device of claim 1, wherein the liquid crystal molecules in the liquid crystal layer (23) are positive liquid crystal molecules, the alignment directions (a1, B1) of the positive liquid crystal molecules corresponding to the first electrode portions (227a) extend in the direction of the first electrode bars (2271), and the alignment directions (a2, B2) of the positive liquid crystal molecules corresponding to the second electrode portions (227B) extend in the direction of the second electrode bars (2272).
6. The viewing-angle switchable liquid crystal display device of claim 1, wherein the liquid crystal molecules in the liquid crystal layer (23) are negative liquid crystal molecules, an alignment direction (a1, B1) of the negative liquid crystal molecules corresponding to each of the first electrode parts (227a) extends in a direction perpendicular to the first electrode bar (2271), and an alignment direction (a2, B2) of the negative liquid crystal molecules corresponding to the second electrode parts (227B) extends in a direction perpendicular to the second electrode bar (2272).
7. A liquid crystal display device switchable in viewing angle according to claim 1, characterized in that, in correspondence with each first electrode portion (227a), an alignment direction (a1) on the first substrate (21) is parallel or antiparallel to an alignment direction (B1) on the second substrate (22); an alignment direction (a2) on the first substrate (21) is parallel or antiparallel to an alignment direction (B2) on the second substrate (22) corresponding to each second electrode portion (227B).
8. A driving method of a viewing angle switchable liquid crystal display device according to any one of claims 1 to 7, wherein the driving method comprises:
in a first viewing angle mode, applying a common voltage to the common electrode (225), and applying a first voltage with a smaller amplitude relative to the common voltage to the viewing angle control electrode (212), so that the voltage difference between the viewing angle control electrode (212) and the common electrode (225) is smaller than a first preset value;
in a second viewing angle mode, a common voltage is applied to the common electrode (225), a second voltage having a larger magnitude than the common voltage is applied to the viewing angle control electrode (212), and a voltage difference between the viewing angle control electrode (212) and the common electrode (225) is greater than a second preset value, wherein the second preset value is greater than or equal to the first preset value.
9. A method of driving a liquid crystal display device with switchable viewing angle according to claim 8, wherein in the first viewing angle mode, the common voltage applied to the common electrode (225) and the first voltage applied to the viewing angle control electrode (212) are both dc voltages and the voltage difference between the two voltages is zero.
10. The driving method of a switchable viewing angle liquid crystal display device of claim 8, wherein the liquid crystal layer (23) 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 (23) 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.
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| CN108563048B (en) * | 2018-04-04 | 2021-09-21 | 昆山龙腾光电股份有限公司 | Peep-proof display panel |
| CN108490696B (en) * | 2018-05-11 | 2021-03-23 | 昆山龙腾光电股份有限公司 | Liquid crystal display device and visual angle switching method thereof |
| CN108519704A (en) * | 2018-05-22 | 2018-09-11 | 昆山龙腾光电有限公司 | Display panel and narrow viewing angle display methods |
| JP2019211568A (en) * | 2018-06-01 | 2019-12-12 | 株式会社ジャパンディスプレイ | Display device |
| CN110673406B (en) * | 2019-09-17 | 2022-07-01 | 昆山龙腾光电股份有限公司 | Liquid crystal display panel with switchable viewing angle and driving method thereof |
| CN110673407B (en) * | 2019-10-11 | 2022-04-22 | 昆山龙腾光电股份有限公司 | Liquid crystal display device having a plurality of pixel electrodes |
| CN111025694B (en) * | 2019-12-11 | 2022-09-23 | 昆山龙腾光电股份有限公司 | Display panel and display device |
| CN111240107A (en) * | 2020-03-18 | 2020-06-05 | 合肥鑫晟光电科技有限公司 | Pixel structure, array substrate, display panel and manufacturing method of display panel |
| CN112748611B (en) * | 2021-01-19 | 2023-07-07 | 北京京东方显示技术有限公司 | Display assembly and electronic equipment |
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