CN1645195A - Adjustable viewing angle LCD display - Google Patents

Abstract

The invention provides a liquid crystal display with adjustable visual angle, which comprises a first substrate, a second substrate and a liquid crystal layer filled between the first substrate and the second substrate. The first substrate includes a first common electrode. The second substrate comprises a pixel electrode, a second common electrode and an insulating layer formed between the pixel electrode and the second common electrode. The liquid crystal display with adjustable visual angle provides a driving voltage on the pixel electrode to lead the first shared electrode to be grounded and lead the second shared electrode to be floated so as to provide a narrow visual angle mode. In addition, the liquid crystal display with adjustable visual angle provides a driving voltage on the pixel electrode, leads the second shared electrode to be grounded and leads the first shared electrode to be floated so as to provide a wide visual angle mode.

Description

Adjustable viewing angle LCD display

technical field

The invention relates to a liquid crystal display with an adjustable viewing angle, in particular to a liquid crystal display with an adjustable viewing angle which facilitates switching between two modes of a wide viewing angle and a narrow viewing angle.

Background technique

As the size of liquid crystal displays gradually increases, conventional twisted nematic type (TN type) liquid crystal displays generally have limitations in viewing angles, that is, images can only be seen from certain angles. In order to improve the limitation of the viewing angle of the liquid crystal display, so that users can watch clear and undistorted images from all angles, there have been many discussions about expanding the viewing angle in the prior art, such as attaching a viewing angle compensation film (viewing angle compensation film), forming different liquid crystal pre-tilt angle directions (pre-tilt angle direction) in a pixel area, and even the proposal of in-plane switching type (IPS type) liquid crystal display.

Although viewing angle expansion technology has become an inevitable trend to improve the contrast ratio of liquid crystal displays, it is desired to limit the viewing angle in some liquid crystal display applications, so that users must view images from specific angles. For example, when a user is manipulating a bank's automatic teller machine or using a notebook computer in an open place, in consideration of security or privacy, it is necessary to use the technology of narrowing the viewing angle to limit the user to only Useful information (clear images) can be seen directly in front of the display, and other people can be prevented from peeking at the image content from other angles such as the side or the top of the user.

Regarding the discussion of viewing angle narrowing technology, in US Patent No. 6,445,434 B2, it is proposed to control the orientation direction (orientation direction) in the liquid crystal display, such as dividing the alignment layer (alignment layer) into multiple regions, and forming in adjacent regions Different alignment directions lead to large differences in optical characteristics such as gray scale inversion, so the image observed by the observer at a large viewing angle becomes very blurred and cannot be recognized. In addition, in U.S. Patent No. 6,239,853 B1 and No. 6,398,370 B1, it is proposed to add a filter device to the liquid crystal display. Only light in a specific direction can pass through the filter device to achieve the purpose of narrow viewing angle.

Although the viewing angle narrowing technology can meet the safety and privacy requirements of users, it relatively sacrifices the viewable viewing angle range and the convenience of use. In order to provide users with more choices, US Patent No. 5,877,829 proposes a liquid crystal display with adjustable viewing angle, which utilizes two optical elements arranged on both sides of the liquid crystal display to control the light entering and exiting the liquid crystal display respectively. Direction, wherein the optical element close to the backlight will limit the direction of the backlight entering the liquid crystal display, the optical element close to the user is actually another liquid crystal layer, and the light transmittance (or scattering rate) can be adjusted to achieve adjustment purpose of perspective.

Although the aforementioned liquid crystal display with adjustable viewing angle allows the user to adjust the light transmittance according to the viewing angle, it needs to add an additional liquid crystal layer, which has certain difficulties in actual production and operation. Therefore, how to reduce the complexity of the liquid crystal display structure and provide a more convenient viewing angle adjustment method has become an important issue.

Contents of the invention

The object of the present invention is to provide a liquid crystal display with adjustable viewing angle, so that the viewing angle can be easily switched between two modes of wide viewing angle and narrow viewing angle.

In a preferred embodiment of the present invention, the liquid crystal display with adjustable viewing angle includes a first substrate, a second substrate, and a liquid crystal layer filled between the first substrate and the second substrate. The first substrate includes a first common electrode. The second substrate includes a pixel electrode, a second shared electrode and an insulating layer formed between the pixel electrode and the second shared electrode. Wherein, in the narrow viewing angle mode, the adjustable viewing angle liquid crystal display provides a driving voltage on the pixel electrode, grounds the first shared electrode, and makes the second shared electrode float; The electrodes provide a driving voltage to ground the second common electrode and float the first common electrode.

Since the present invention can utilize the potential switching between the first common electrode and the second common electrode to select the narrow viewing angle mode or the wide viewing angle mode, the operation is very convenient. Moreover, compared with other adjustable viewing angle liquid crystal displays requiring two layers of liquid crystal layers, the liquid crystal display of the present invention obviously has advantages in structure simplification and manufacturing cost, which is beneficial to the development and application of adjustable viewing angle liquid crystal displays.

Description of drawings

1 is a schematic cross-sectional view of an adjustable viewing angle liquid crystal display of the present invention;

2 is a schematic diagram of the light polarization direction and alignment direction of a liquid crystal display with an adjustable viewing angle according to the present invention;

3 is a schematic diagram of the light polarization direction and alignment direction of a liquid crystal display with an adjustable viewing angle according to another embodiment of the present invention;

FIG. 4 and FIG. 5 are schematic diagrams of bright and dark state operations of a liquid crystal display with an adjustable viewing angle in a narrow viewing angle mode according to the present invention;

FIG. 6 and FIG. 7 are schematic diagrams of bright and dark state operations of an adjustable viewing angle liquid crystal display in a wide viewing angle mode according to the present invention;

FIG. 8 is a schematic diagram of alignment directions of an adjustable viewing angle liquid crystal display according to another embodiment of the present invention.

Explanation of reference signs

10, 20 Substrate

12, 26 Shared electrodes

22 Pixel electrode

24 Insulation layer

30 Liquid crystal layer

32, 34 Light polarization direction

36, 38, 40, 42, 44, 46 alignment direction

a, b area

Detailed ways

Please refer to FIG. 1 . FIG. 1 is a schematic cross-sectional view of a liquid crystal display with an adjustable viewing angle according to the present invention. As shown in FIG. 1 , the liquid crystal display with adjustable viewing angle of the present invention includes two parallel substrates 10 and 20 , and a liquid crystal layer 30 filled between the substrates 10 and 20 . In a preferred embodiment of the present invention, the substrate 10 is a color filter substrate, which includes a plurality of red filters, green filters, blue filters and black matrix structures (not shown in the figure) , so that light can penetrate it to produce three primary colors such as red, green and blue, and then form a color image. The substrate 20 is a thin film transistor substrate, which includes elements such as thin film transistors arranged in an array, capacitors, scanning lines and signal lines (not shown in the figure) vertically interlaced to drive pixel electrodes and control liquid crystal steering. However, the present invention is not limited thereto, and the substrate 20 can also be a COA (color filter on array) substrate or an AOC (array on color filter) substrate, that is, the substrate 20 can include structures such as color filters and thin film transistors, As for the substrate 10, it can be a glass or plastic substrate without color filters.

In addition, the surface of the substrate 10 includes a shared electrode 12 , the surface of the substrate 20 includes a pixel electrode 22 , an insulating layer 24 covers the surface of the pixel electrode 22 , and a shared electrode 26 is disposed on the insulating layer 24 . In a preferred embodiment of the present invention, the shared electrode 12 , the pixel electrode 22 and the shared electrode 26 are all transparent electrodes formed of transparent conductive layers such as indium tin oxide (ITO) or indium zinc oxide (IZO). The insulating layer 24 can be a transparent protective layer, such as silicon dioxide, silicon nitride or an organic material layer. Since the adjustable viewing angle liquid crystal display of the present invention provides a wide viewing angle mode similar to the plane switching type, the preferred configuration of the shared electrode 26 is only formed on a part of the pixel electrode 22. For example, the shared electrode 26 may include a plurality of edges along a first Protrusions are arranged in a direction, and two adjacent shared electrodes 26 are separated by a predetermined distance, so as to expose part of the surface of the pixel electrode 22 .

Please refer to FIG. 2 . FIG. 2 is a schematic diagram of the light polarization direction and the alignment direction of a liquid crystal display with an adjustable viewing angle according to the present invention. The left part of the figure shows the liquid crystal turning of the liquid crystal display in a dark state, and the right part of the figure shows the liquid crystal turning of the liquid crystal display in a bright state. 4 to 7 of the present invention. As shown in Figure 2, in a preferred embodiment of the present invention, the substrate 10 provides a light polarization direction (polarizing direction) 32 indicated by a solid line and an alignment direction (rubbing direction) 36 indicated by a dotted line, and the substrate 20 provides a A light polarization direction 34 marked with a solid line and an alignment direction 38 marked with a dotted line, and wherein the light polarization direction 32 and the light polarization direction 34 are parallel to each other, the alignment direction 36 is parallel to the alignment direction 38 but in opposite directions, and the alignment direction 36 is parallel to the alignment direction 38 The light polarization directions 32 form an included angle, preferably between 0-90 degrees, and the alignment direction 38 and the light polarization direction 34 also form an included angle, preferably between 0-90 degrees.

Please refer to FIG. 3 . FIG. 3 is a schematic diagram of light polarization directions and alignment directions of an adjustable viewing angle liquid crystal display according to another embodiment of the present invention. The left part of the figure shows the liquid crystal turning when the liquid crystal display is in a bright state, and the right part of the figure shows the liquid crystal turning when the liquid crystal display is in a dark state. 4 to 7 of the present invention. The difference between this embodiment and the embodiment shown in FIG. 2 is that the light polarization direction 32 and the light polarization direction 34 shown in FIG. 3 are perpendicular to each other, while the light polarization direction 32 and the light polarization direction 34 shown in FIG. 2 are parallel to each other. , this difference also causes the liquid crystal to change when it is in the bright state and the dark state.

The narrow viewing angle mode provided by the adjustable viewing angle liquid crystal display of the present invention is an inverted viewing angle mode, which forms serious differences in optical characteristics such as grayscale inversion at large viewing angles, making the images observed by observers at large viewing angles very blurred and cannot be identified. In order to achieve the above object, the adjustable viewing angle liquid crystal display of the present invention utilizes the shared electrode 12 and the pixel electrode 22 to provide a vertical electric field direction in the narrow viewing angle mode, for example, a driving voltage V is provided at the pixel electrode 22, so that the shared electrode 12 is grounded, and The common electrode 26 is floated to control the steering of the liquid crystal.

Please refer to FIG. 4 and FIG. 5 . FIG. 4 and FIG. 5 are schematic diagrams for further illustrating the bright and dark state operation of the adjustable viewing angle liquid crystal display in the narrow viewing angle mode of the present invention. As shown in FIG. 4 , under the condition that no electric field is applied, since the liquid crystal molecules of the liquid crystal layer 30 are arranged according to the alignment directions 36 and 38, and the alignment direction 36 and the light polarization direction 32, and the alignment direction 38 and the light polarization direction 34 They all have included angles, so controlling the included angles so that the alignment direction 36 is not parallel to the light polarization direction 32 and the alignment direction 38 is not parallel to the light polarization direction 34 will cause phase delay and change the linear polarization state of light. In the case where the light polarization directions 32 and 34 are parallel (i.e. the embodiment shown in FIG. 2 ), the light can not pass through the polarizer (not shown in the figure) outside the substrate 10 after passing through the substrate 20 and the liquid crystal layer 30, so , the observer above the substrate 10 cannot see any light, which is the dark state of the liquid crystal display. As shown in Figure 5, since the liquid crystal layer 30 is a positive type liquid crystal, it tends to be vertically arranged in accordance with the direction of the electric field under the supply of an external electric field. , the alignment direction of the liquid crystal will be perpendicular to the light polarization directions 32, 34, so that the light will not cause phase delay and change of the linear polarization state of the light after passing through the substrate 20 and the liquid crystal layer 30, so it can pass through the polarizer on the outside of the substrate 10 (not shown in the figure), so that the observer located above the substrate 10 can see the light, which is the bright state of the liquid crystal display. In addition, when the light polarization directions 32 and 34 are perpendicular to each other as shown in FIG. 3 , the bright and dark states are just opposite, that is, the situation in FIG. 4 is a bright state, and the situation in FIG. 5 is a dark state. However, due to factors such as the pre-tilt angle of the liquid crystal molecules and the uniformity of the electric field distribution, the observer can only recognize the image directly in front of the LCD in the bright state, and cannot recognize the image at a large viewing angle due to serious grayscale inversion. , which is the narrow viewing angle mode, also known as the inverse viewing angle mode.

In addition, the wide viewing angle mode of the adjustable viewing angle liquid crystal display of the present invention utilizes the shared electrode 26 and the pixel electrode 22 to provide a lateral electric field direction, for example, a driving voltage V is provided at the pixel electrode 22 to make the shared electrode 12 float, and to make the shared electrode 26 is grounded to control the steering of the liquid crystal.

Please refer to FIG. 6 and FIG. 7 . FIG. 6 and FIG. 7 are schematic diagrams for further illustrating the bright and dark state operation of the adjustable viewing angle liquid crystal display in the wide viewing angle mode of the present invention. As shown in FIG. 6 , in the case of no electric field applied, since the liquid crystal molecules of the liquid crystal layer 30 are arranged according to the alignment directions 36 and 38, and between the alignment direction 36 and the light polarization direction 32, and between the alignment direction 38 and the light polarization direction 34 They all have included angles, so controlling the included angles so that the alignment direction 36 is not parallel to the light polarization direction 32 and the alignment direction 38 is not parallel to the light polarization direction 34 will cause phase delay and change the linear polarization state of light. In the case where the light polarization directions 32 and 34 are parallel (that is, the embodiment shown in FIG. 2 ), after the light passes through the substrate 20 and the liquid crystal layer 30, it cannot pass through the polarizer (not shown in the figure) outside the substrate 10, Therefore, the observer above the substrate 10 cannot see any light, which is the dark state of the liquid crystal display. As shown in Figure 7, since the liquid crystal layer 30 is a positive type liquid crystal, it tends to be aligned in parallel with the direction of the electric field under the supply of an external electric field. , the liquid crystal alignment direction will be parallel to the light polarization direction 32 or 34, so that the light will not cause phase delay and linear polarization state change after passing through the substrate 20 and the liquid crystal layer 30, so it can pass through the polarizer on the outside of the substrate 10 (not shown in the figure), so that the observer located above the substrate 10 can see the light, which is the bright state of the liquid crystal display. In addition, when the light polarization directions 32 and 34 are arranged perpendicular to each other as shown in FIG. 3 , the bright and dark states are just opposite, that is, the situation in FIG. 6 is a bright state, and the situation in FIG. 7 is a dark state. Since the shared electrode 26 is designed similar to the electrode structure of the in-plane switching mode to change the alignment direction of the liquid crystal molecules and provide a wide viewing angle effect similar to the in-plane switching mode, the observer can watch clear and undistorted images from various angles.

Furthermore, in addition to arranging the light polarization direction and the alignment direction of the liquid crystal layer according to the designs shown in Fig. 2 and Fig. 3, the liquid crystal display with adjustable viewing angle of the present invention can also use a twisted nematic mode similar to other embodiments of the present invention. Designed to arrange the light polarization direction and the alignment direction of the liquid crystal layer. Please refer to FIG. 8 . FIG. 8 is a schematic diagram of an alignment direction of an adjustable viewing angle liquid crystal display according to another embodiment of the present invention. As shown in FIG. 8 , in this embodiment, the surface of the substrate 10 is divided into a plurality of different regions a and b, and each region a and its adjacent regions b have different alignment directions, for example, the alignment of region a The direction 40 is parallel to but opposite to the alignment direction 42 of the region b, and the light polarization direction (not shown) of the substrate 10 is parallel to the alignment directions 40 , 42 . Similarly, the surface of another substrate 20 is also divided into a plurality of different regions a and b, and each region a and its adjacent region b have different alignment directions, for example, the alignment direction 44 of region a is different from that of region b. The alignment directions 46 are parallel but opposite, and the light polarization direction (not shown) of the substrate 20 is parallel to the alignment directions 44 , 46 . According to the theory of the twisted nematic mode, the light polarization direction of the substrate 10 and the light polarization direction of the substrate 20 are perpendicular to each other, that is to say, the alignment directions 40, 42 on the substrate 10 and the alignment directions 44, 46 on the substrate 20 are perpendicular to each other. Therefore, this embodiment can arrange the light polarization direction and the alignment direction of the liquid crystal layer according to the design similar to the twisted nematic mode, which is applied to the electrode structure design shown in Figure 1, and utilizes the potential switching between the shared electrode 12 and the shared electrode 26 , to achieve the purpose of selecting a narrow viewing angle mode (twisted nematic mode) or a wide viewing angle mode (plane switching mode).

Compared with the existing wide viewing angle liquid crystal display or narrow viewing angle liquid crystal display that cannot provide viewing angle switching options, the present invention can use the switching of the shared electrode potential of the two substrates to select the narrow viewing angle mode or wide viewing angle mode, such as providing on the liquid crystal display housing One is electrically connected to the button for controlling the above-mentioned common electrode potential switching circuit, so that the user can switch between the wide viewing angle mode and the narrow viewing angle mode according to the viewing angle requirement, so the operation is very convenient. Moreover, compared with other adjustable viewing angle liquid crystal displays that require two layers of liquid crystal layers, the liquid crystal display of the present invention obviously has the advantages of simplified structure and manufacturing cost, which is conducive to the development and application of adjustable viewing angle liquid crystal displays.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention shall fall within the scope of the patent of the present invention.

Claims (11)

1. liquid crystal displaying device with adjustable visual angle, it comprises:

One first substrate, this first substrate comprises one first shared electrode;

One second substrate, this second substrate is parallel to this first substrate, and this second substrate comprises a pixel electrode, and one second shared electrode be located at this first electrode top, wherein this second shared electrode comprises many thrusts of arranging along first direction, and respectively all comprises a spacing distance between this thrust; And

One liquid crystal layer is filled between this first substrate and this second substrate;

Wherein this first shared electrode and this pixel electrode can provide a vertical electric field direction under a narrow field-of-view mode, and this second shared electrode and this pixel electrode can produce a transverse electric field under a wide viewing angle pattern, turn to the liquid crystal molecule that drives in this liquid crystal layer down respectively at different field-of-view modes.

2. liquid crystal displaying device with adjustable visual angle as claimed in claim 1, wherein this first substrate comprises a colored filter substrate.

3. liquid crystal displaying device with adjustable visual angle as claimed in claim 1, wherein this second substrate comprises a thin film transistor base plate.

4. liquid crystal displaying device with adjustable visual angle as claimed in claim 1, wherein this first substrate provides one first light polarization direction, and this second substrate provides one second light polarization direction, and this first light polarization direction is parallel to this second light polarization direction.

5. liquid crystal displaying device with adjustable visual angle as claimed in claim 4, wherein this first substrate provides one first alignment direction, and this second substrate provides one second alignment direction, and this first alignment direction is parallel to this second alignment direction.

6. liquid crystal displaying device with adjustable visual angle as claimed in claim 5, wherein the angle between this first alignment direction and this first light polarization direction is between the 0-90 degree.

7. liquid crystal displaying device with adjustable visual angle as claimed in claim 1, wherein this first shared electrode, this second shared electrode and this pixel electrode are a transparency electrode.

8. liquid crystal displaying device with adjustable visual angle as claimed in claim 1, wherein this first substrate provides one first light polarization direction, and this second substrate provides one second light polarization direction, and this first light polarization direction is perpendicular to this second light polarization direction.

9. liquid crystal displaying device with adjustable visual angle as claimed in claim 8, wherein this first substrate provides one first alignment direction, and this first alignment direction is parallel to this first light polarization direction.

10. liquid crystal displaying device with adjustable visual angle as claimed in claim 8, wherein this second substrate provides one second alignment direction, and this second alignment direction is parallel to this second light polarization direction.

11. liquid crystal displaying device with adjustable visual angle as claimed in claim 1, it comprises an insulation course in addition and is formed between this pixel electrode and this second shared electrode.

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