KR100935851B1 - Liquid Crystal Display - Google Patents

Abstract

The present invention relates to a liquid crystal display device. The liquid crystal display of the present invention includes a first insulating substrate, a first electrode and a second electrode formed on one surface of the first insulating substrate and forming horizontal electric fields therebetween, and formed on the first electrode and the second electrode. A lower substrate including a first horizontal alignment layer having a rubbing axis in a predetermined direction; A third electrode disposed to face the lower substrate and formed on a second insulating substrate, a surface of the second insulating substrate and forming a vertical electric field with the first electrode and the second electrode, and formed on the third electrode; An upper substrate including a second horizontal alignment layer having a rubbing axis parallel to the rubbing axis of the first horizontal alignment layer; And a liquid crystal layer interposed between the lower substrate and the upper substrate and including liquid crystal molecules.

As described above, the liquid crystal display of the present invention can implement a wide viewing angle mode and a narrow viewing angle mode using horizontal switching in a splay state and vertical switching in a 180 ° twist state.

LCD, wide viewing angle, narrow viewing angle, splay, twist, horizontal electric field, vertical electric field

Description

Liquid Crystal Display

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that can adjust the viewing angle according to the nature of the information displayed on the screen.

Today, with the advent of the information age, the demand for high performance displays displaying various information such as images, graphics, and characters is rapidly increasing for the rapid delivery of various information. In response to such demands, the display industry is showing rapid growth.

In particular, liquid crystal displays (LCDs) have been greatly advanced for many years as next-generation advanced display devices that have lower power consumption, lighter weight, and no harmful electromagnetic waves than the cathode ray tube (CRT). Recently, in the era of high-definition digital broadcasting, a liquid crystal display device with a plasma display panel (PDP) as a large-screen display of 30 inches or more has attracted much attention.

A liquid crystal display device is a display device that displays an image by changing the arrangement of liquid crystal molecules by an electric field formed between an electrode disposed on two substrates by injecting a liquid crystal, which is an intermediate material between solid and liquid, between two substrates. It is widely used for applications such as electronic calculators, PCs, and TVs, and has been specially developed for its use. On the other hand, in recent years, in order to use a single liquid crystal display device for various purposes, efforts are being actively made to have all the performances corresponding to each use.

In particular, information that needs to be kept secret and not exposed to others, such as account information that appears in ATMs or text messages sent to and received from mobile phones, depending on the nature of the information, is only visible to the user and invisible to others around him. You'll need a display, and if you're watching a presentation, sporting event, or movie, you'll need a display that's visible to all viewers. Therefore, by properly adjusting the viewing angle according to the nature of the information displayed on the screen, it is possible to exclude the access to the surrounding information by narrowing the viewing angle in the case of information that needs to be kept secret, and widening the viewing angle in the case of information requiring performance. There is an increasing demand for liquid crystal display devices that can be viewed at.

The technical problem to be achieved by the present invention is to provide a liquid crystal display device that can implement a wide viewing angle and narrow viewing angle that can satisfy both the confidentiality and the performance of the information by adjusting the viewing angle according to the nature of the information displayed on the screen There is.

In order to achieve the above technical problem, the present invention is a first insulating substrate, a first electrode and a second electrode formed on one surface of the first insulating substrate and forming a horizontal electric field between each other, and the first electrode and the second A lower substrate including a first horizontal alignment layer having a rubbing axis in a predetermined direction formed on the electrode; A third electrode disposed to face the lower substrate and formed on a second insulating substrate, a surface of the second insulating substrate and forming a vertical electric field with the first electrode and the second electrode, and formed on the third electrode; An upper substrate including a second horizontal alignment layer having a rubbing axis parallel to the rubbing axis of the first horizontal alignment layer; And a liquid crystal layer interposed between the lower substrate and the upper substrate, the liquid crystal layer comprising liquid crystal molecules.

The liquid crystal display includes: a first polarizer disposed on a surface opposite to a surface on which the first and second electrodes are formed on the lower substrate and having a polarization axis parallel to the rubbing axis of the first alignment layer; And a second polarizer disposed on a surface opposite to a surface on which the third electrode of the upper substrate is formed and having a polarization axis perpendicular to the polarization axis of the first polarizer.

The first electrode and the second electrode may be formed in an electrode structure of the FFS mode. In this case, the first electrode is formed on the first insulating substrate in a plate-like structure, the second electrode is formed on the first electrode with an insulating film therebetween two or more branches arranged side by side at a predetermined interval It may include a connecting portion connecting the portion and the branch.

On the other hand, the first electrode and the second electrode may be formed in the electrode structure of the IPS mode. In this case, the first electrode is formed on the first insulating substrate and includes at least two branch portions arranged side by side at a predetermined interval and connecting portions connecting the branch portions, and the second electrode has an insulating film therebetween. It may include two or more branches and the connecting portion connecting the branches are arranged insulated from the first electrode and arranged side by side at a predetermined interval. Here, the branch portion of the first electrode and the branch portion of the second electrode are alternately arranged.

The liquid crystal molecules are arranged in a splay state when forming a horizontal electric field between the first electrode and the second electrode, and are arranged in a twisted state when forming a vertical electric field between the first electrode and the second electrode and the third electrode.

The liquid crystal layer may further include a chiral dopant.

The present invention also provides a first insulating substrate, a first electrode and a second electrode formed on one surface of the first insulating substrate and forming a horizontal electric field between each other, and a concave-convex pattern on the first electrode and the second electrode. A lower substrate formed thereon and including a first vertical alignment layer having a rubbing axis in a predetermined direction; A third electrode disposed to face the lower substrate and formed on one surface of the second insulating substrate, the second insulating substrate and forming a vertical electric field with the first electrode and the second electrode, and the third electrode; An upper substrate including a second vertical alignment layer having a rubbing axis in a direction parallel or perpendicular to a rubbing axis of the first vertical alignment layer; And a liquid crystal layer interposed between the lower substrate and the upper substrate, the liquid crystal layer comprising liquid crystal molecules.

The liquid crystal display is disposed on a surface opposite to a surface on which the first electrode and the second electrode are formed on the first insulating substrate, and has a polarization axis in a 45 ° direction or parallel to the rubbing axis of the first alignment layer. 1 polarizer; And a second polarizing plate disposed on a surface opposite to a surface on which the third electrode of the second insulating substrate is formed and having a polarization axis perpendicular to the polarization axis of the first polarizing plate.

The first electrode and the second electrode may be formed in an electrode structure of the FFS mode. In this case, the first electrode is formed on the first insulating substrate in a plate-like structure, the second electrode is formed on the first electrode with an insulating film therebetween, two or more arranged side by side at a predetermined interval It may include a branch portion and a connecting portion connecting the branch portion.

On the other hand, the first electrode and the second electrode may be formed in the electrode structure of the IPS mode. In this case, the first electrode is formed on the first insulating substrate, and includes two or more branches arranged side by side at a predetermined interval and a connecting portion connecting the branches, wherein the second electrode is formed between the insulating film. Two or more branches disposed at side by side with a predetermined distance and a connection part connecting the branches, wherein the branches of the first electrode and the branches of the second electrode alternate with each other. Can be deployed.

The liquid crystal molecules on the uneven pattern are vertically aligned when forming a positive vertical electric field between the first electrode and the second electrode, and are horizontally aligned when forming a negative vertical electric field.

In addition, the liquid crystal molecules are vertically aligned when a negative vertical electric field is formed between the lower substrate electrode, that is, the first electrode and the second electrode, and the upper substrate electrode, that is, the third electrode, and horizontally when the positive vertical electric field is formed. A negative vertical electric field is a case where a negative voltage is applied to the upper substrate, and a positive vertical electric field is a case where a positive voltage is applied to the upper substrate.

The present invention also provides a first insulating substrate, a first electrode and a second electrode formed on one surface of the first insulating substrate and forming a horizontal electric field between each other, and a concave-convex pattern on the first electrode and the second electrode. A lower substrate formed thereon and including a vertical alignment layer having a rubbing axis in a predetermined direction; A third electrode disposed to face the lower substrate and formed on a second insulating substrate, a surface of the second insulating substrate and forming a vertical electric field with the first electrode and the second electrode, and formed on the third electrode; An upper substrate including a horizontal alignment layer having a rubbing axis in a direction parallel or perpendicular to a rubbing axis of the vertical alignment layer; And a liquid crystal layer interposed between the lower substrate and the upper substrate, the liquid crystal layer comprising liquid crystal molecules.

The liquid crystal display device may include a first polarization axis disposed on a surface opposite to a surface on which the first electrode and the second electrode are formed on the first insulating substrate and having a polarization axis in a 45 ° direction or parallel to the rubbing axis of the vertical alignment layer. Polarizers; And a second polarizing plate disposed on a surface opposite to a surface on which the third electrode of the second insulating substrate is formed, and having a polarizing axis perpendicular to the polarizing axis of the first polarizing plate.

The first electrode and the second electrode may be formed in an electrode structure of the FFS mode. In this case, the first electrode is formed on the first insulating substrate in a plate-like structure, the second electrode is formed on the first electrode with an insulating film therebetween, two or more arranged side by side at a predetermined interval It may include a branch portion and a connecting portion connecting the branch portion.

The first electrode and the second electrode may be formed in the electrode structure of the IPS mode. In this case, the first electrode is formed on the first insulating substrate, and includes two or more branches arranged side by side at a predetermined interval and a connecting portion connecting the branches, wherein the second electrode is formed between the insulating film. Two or more branches disposed at side by side with a predetermined distance and a connection part connecting the branches, wherein the branches of the first electrode and the branches of the second electrode alternate with each other. Can be deployed.

The liquid crystal molecules are vertically aligned when forming a positive vertical electric field between the first electrode and the second electrode and a third electrode, and are horizontally aligned when forming a negative vertical electric field.

In addition, the liquid crystal molecules are vertically aligned when the negative vertical electric field is formed between the first electrode and the second electrode and the third electrode, and are horizontally aligned when the positive vertical electric field is formed.

As described above, the liquid crystal display device of the present invention can implement the wide viewing angle mode and the narrow viewing angle mode by using the bistable stability of the liquid crystal. Therefore, when confidentiality is required, such as account information, the user can switch to narrow viewing angle mode to exclude other people's information access, and when demanding performance such as presentation or movie, switch to wide viewing angle mode to view from a wide angle. As a result, information can be used more efficiently.

Hereinafter, the present invention will be described in more detail with reference to the drawings. In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

When an element or layer is referred to as being "on" or "on" another element or layer, it encompasses both the case directly above another element or layer as well as intervening another layer or element. On the other hand, when an element is referred to as "directly" or "directly above", it means that no other element or layer is interposed in between.

The spatially relative terms "bottom", "bottom", "top", "top", "between", and the like, as shown in the figure, correlate one device or component with another device or components. Can be used to easily describe the relationship. These terms include not only when the elements or components are in direct contact, but also when other elements or components are interposed therebetween. Since such terms indicate relative positional relations, they should be understood to include various other directions such as elements in use or operation in addition to the directions shown in the drawings.

First, the liquid crystal molecule arrangement state of the liquid crystal display according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1 and 2 are views schematically showing an arrangement state of liquid crystal molecules of a liquid crystal display according to a first embodiment of the present invention, in which FIG. 1 shows a splay state and FIG. 2 shows a twist state.

1 and 2, the liquid crystal display according to the first exemplary embodiment of the present invention includes an alignment layer having the same rubbing axis D1 on the upper substrate 200 and the lower substrate 100. Accordingly, in the liquid crystal display according to the present exemplary embodiment, two stable alignment states of the liquid crystal molecules 310, that is, a splay state in which the liquid crystal molecules 310 are not twisted and the liquid crystal molecules 310 are twisted 180 ° are arranged. Has a twisted state. The liquid crystal display according to the present exemplary embodiment implements a wide viewing angle mode and a narrow viewing angle mode by using the two liquid crystal molecule arrangement states.

Next, a liquid crystal display according to a first embodiment of the present invention will be described with reference to FIG. 3. 3 is a perspective view schematically showing a liquid crystal display according to a first embodiment of the present invention.

The liquid crystal display of the present embodiment includes an upper substrate 200, a lower substrate 100, and a liquid crystal layer interposed therebetween.

The lower substrate 100 may include a first insulating substrate 110 formed of glass or a transparent polymer material, a first electrode 130 and a second electrode 150 formed on one surface of the first insulating substrate 110, and a first insulating substrate 110. The first horizontal alignment layer 170 is formed on the first electrode 130 and the second electrode 150.

The first electrode 130 is disposed on the first insulating substrate 110 in a plate shape, and the second electrode 150 is disposed in a stripe shape on the first electrode 130 with the insulating layer 140 interposed therebetween. do. That is, the second electrode 150 includes two or more branch parts 150b arranged side by side at predetermined intervals and a connection part 150a connecting the branch parts 150b. The first electrode 130 and the second electrode 150 horizontally switch the liquid crystal molecules 310 through horizontal electric fields formed therebetween. The first electrode 130 and the second electrode 150 may be formed of a transparent conductive material such as ITO and IZO.

The first electrode 130 employs the structure of the pixel electrode and the counter electrode of the FFS mode liquid crystal display. However, the structures of the first electrode 130 and the second electrode 150 are not limited thereto, and the structures of the pixel electrode and the counter electrode of the conventional IPS mode liquid crystal display may be adopted, as well as the horizontal electric field. It can be employed without limitation as long as it is a structure capable of forming a horizontal switching.

When employing the pixel electrode and counter electrode structures of the IPS mode liquid crystal display, the first electrode is formed on the first insulating substrate to include two or more branches arranged side by side at a predetermined interval and a connecting portion connecting the branches. The second electrode is insulated from the first electrode with an insulating film interposed therebetween so as to include at least two branch parts arranged side by side at a predetermined interval and a connection part connecting the branch parts. Here, the branch portion of the first electrode and the branch portion of the second electrode are alternately arranged to form a horizontal electric field therebetween.

Gate lines (not shown) and data lines (not shown) formed of a metal such as aluminum, chromium, tantalum, or molybdenum are alternately arranged on the first insulating substrate 110, and at the intersections of the gate lines and the data lines, a switching element is provided. A thin film transistor (not shown) is disposed. The thin film transistor includes a gate electrode, a drain electrode, a source electrode, an active layer, and an ohmic contact layer for switching.

On the second electrode 150, a first horizontal alignment layer 170 is formed of a polymer material such as polyimide or polyamide. The first horizontal alignment layer 170 is rubbed to have a rubbing axis in a predetermined direction D2.

The second substrate having a polarization axis in a direction D2 parallel to the rubbing axis of the first horizontal alignment layer 170 on the surface opposite to the surface on which the first electrode 130 and the second electrode 150 are formed. 1 polarizer 180 is disposed. The first polarizer may be formed of a polyvinyl alchol (PVA) film, a triacetyl cellulose (TAC) film, or the like.

The upper substrate 200 is disposed to face the lower substrate 100, and the second insulating substrate 210 formed of glass or a transparent polymer material and the third electrode 230 formed on one surface of the second insulating substrate 210. And a second horizontal alignment layer 270 formed on the third electrode 230.

The third electrode 230 is disposed on the second insulating substrate 210 in a plate shape to form a vertical electric field together with the first electrode 130 and the second electrode 150. The third electrode 230 may be formed of a transparent conductive material such as ITO or IZO.

A black matrix (not shown) and a color filter (not shown) for realizing color may be formed between the second insulating substrate 210 and the third electrode 230.

The black matrix blocks light transmitted through an uncontrollable area of the liquid crystal molecules and prevents light leakage current of the thin film transistor by blocking direct light irradiation to the channel of the thin film transistor, and is an opaque organic material or an opaque material. It may be formed of a metal.

The color filter is formed in the area partitioned by the black matrix for realizing color. Color filters include red, green, and blue color filters (R, G, B) and include red, green, and blue colors by absorbing or transmitting light of a particular wavelength through the red, green, and blue pigments they contain. Implement a variety of colors.

An overcoat layer (not shown) may be provided on the black matrix and the color filter to protect the color filter and reduce the step difference generated between the black matrix and the color filter.

The second horizontal alignment layer 270 is formed on the third electrode 230 by using a polymer material such as polyimide or polyamide. The second horizontal alignment layer 270 is rubbed to have a rubbing axis in a direction D2 parallel to the rubbing axis of the first horizontal alignment layer 170. By making the rubbing axes of the first horizontal alignment layer 170 and the second horizontal alignment layer 270 parallel to each other, the liquid crystal molecules 310 may be arranged in a splay or twisted state of 180 °.

A second polarizer 280 having a polarization axis in a direction D3 perpendicular to the polarization axis of the first polarizer 180 is disposed on a surface opposite to the surface on which the third electrode 230 is formed on the upper substrate 200. It may be formed of a PVA (PolyVinyl Alchol) film, TAC (Tri Acetyl Cellulose) film.

Hereinafter, a method of implementing the wide viewing angle mode and the narrow viewing angle mode will be described with reference to FIGS. 4 to 7. 4 to 7 are diagrams for describing an operating principle of the liquid crystal display according to the first embodiment of the present invention.

4 and 5 illustrate a wide viewing angle mode using horizontal switching in the splay state. FIG. 4 illustrates a case where the first electrode 130 and the second electrode 150 are turned off. The case where ON is made between 130 and the second electrode 150 is shown. The vertical electric field is removed by turning OFF between the first and second electrodes 130 and 150 of the lower substrate 100 and the third electrode 230 of the upper substrate 200, and the first electrode 130 and the second electrode ( When the horizontal electric field is applied by turning ON, the liquid crystal molecules 310 are arranged in a splay state as shown in FIG. 4 to operate in the wide viewing angle mode. In this state, the splay state is maintained until the ON between the first and second electrodes 130 and 150 and the third electrode 230 is turned on, and the electric field between the first and second electrodes 130 and 150 is adjusted. The light transmittance can be adjusted by changing the rotation angle of the liquid crystal molecules 310. As shown in FIGS. 4 and 5, the horizontal switching in the splay state is the same as the FFS mode of the normally black, so that very good dark and bright characteristics can be obtained to show a wide viewing angle. give.

6 and 7 illustrate a narrow viewing angle mode using vertical switching in a 180 ° twisted state, and FIG. 6 illustrates a case where the first and second electrodes 130 and 150 and the third electrode 230 are turned off. FIG. 7 illustrates a case where the first and second electrodes 130 and 150 and the third electrode 230 are turned on. When the first electrode 130 and the second electrode 150 are connected, and the electric field is applied by turning ON between them and the third electrode 230, the liquid crystal molecules 310 are twisted in a 180 ° state as shown in FIG. 6. Arranged to switch from wide viewing angle mode to narrow viewing angle mode. Here, the first electrode 130 and the second electrode 150 may be short-circuited and used as one electrode, but only one of the first electrode 130 and the second electrode 150 may be used to form the third electrode 230. A vertical electric field may be formed between and. In this state, the twisted state is maintained before the vertical electric field is removed and the horizontal electric field is applied, and the light transmittance can be adjusted by changing the rotation angle of the liquid crystal molecules 310 by adjusting the vertical electric field. As shown in FIGS. 6 and 7, the vertical switching in the twisted state is normally white, and the dark characteristic at the front side is excellent, but the liquid crystal molecules 310 are in a standing state. The characteristic shows a narrow viewing angle characteristic.

As described above, when switching to the wide viewing angle mode and switching to the narrow viewing angle mode, a vertical electric field is applied to create a twisted state, and when switching from the narrow viewing angle mode to the wide viewing angle mode, a horizontal electric field is applied to create a splay state. However, since the 180 ° twisted state is a metastable state, a stable 180 ° twisted state can be maintained by refreshing every predetermined time or by mixing a small amount of chiral dopant in the liquid crystal layer.

8A and 8B show photographs of horizontal switching in the splay state when the cell gap is 5 μm and the birefringence is 0.1. 8A shows an excellent dark characteristic with an optical image before applying voltage, and FIG. 8B shows a good bright characteristic with an optical image when applying a voltage of 4V. 9A and 9B show photographs vertically switched in a 180 ° twist state when the cell gap is 5 μm and the birefringence is 0.1. 9A shows an optical image before applying voltage and does not show good bright characteristics, while FIG. 9B shows a good dark characteristic with an optical image when applying a voltage of 1.5V, but the dark characteristic is not good from the side, and thus shows a narrow viewing angle. give.

Until now, the liquid crystal display device that implements the narrow viewing angle and the wide viewing angle by using the bistable stability of the liquid crystal splay and twisted state has been described. Hereinafter, the liquid crystal display device which can realize the narrow viewing angle and the wide viewing angle in a different manner is described. Look at it.

10A and 10B are diagrams for explaining an arrangement state of the liquid crystal 310 in the vertical alignment layers 170a and 170b having the uneven pattern. As shown in FIGS. 10A and 10B, when the uneven pattern, that is, the expression pattern having the curvature, is formed on the surfaces of the vertical alignment layers 170a and 170b having vertical alignment characteristics, the liquid crystals on the vertical alignment layers 170a and 170b may be formed. 310 has two stable orientation states, vertical or horizontal. Since this surface has a flexoelectric effect, two states can be selected by the direction of the electric field (+,-). Therefore, by using the uneven pattern, a liquid crystal display device capable of realizing both a narrow viewing angle and a wide viewing angle can be manufactured.

11A and 11B schematically illustrate a liquid crystal arrangement state of a liquid crystal display according to a second exemplary embodiment of the present invention. 11A and 11B, when the vertical alignment layer having the uneven pattern is disposed on the lower substrate 100 and the vertical alignment layer is disposed on the upper substrate 200, the surface having the bistable stability of the lower substrate 100 is provided. When the vertical alignment is performed, the liquid crystal 310 is initially vertically aligned as in the VA (vertical alignment) mode, and when the surface having the bistable stability of the lower substrate 100 is horizontally aligned, the liquid crystal 310 is initially HAN ( As in Hybrid aligned nematic mode, the top is vertically down and the horizontal bulk is in medium oblique orientation.

In the VA mode using positive liquid crystals, horizontal switching is used together with a VA compensation film to achieve a wide viewing angle, and a vertical viewing angle is used together with a VA compensation film in a HAN mode to achieve a narrow viewing angle. On the other hand, when the horizontal switching is used together with the HAN-only compensation film in VA mode using positive liquid crystal, narrow viewing angle can be realized, and when the vertical switching is used together with the HAN-only compensation film in the HAN mode, wide viewing angle can be realized.

The lower substrate 100 of the liquid crystal display according to the present exemplary embodiment includes a first electrode and a second electrode forming a horizontal electric field, and are formed to have an uneven pattern on the first electrode and the second electrode, and rubbing in a predetermined direction. And a first vertical alignment layer having an axis. In addition, the upper substrate 200 includes a first electrode and a third electrode forming a vertical electric field with the second electrode, and a second axis having a rubbing axis in a direction parallel or perpendicular to the rubbing axis of the vertical alignment layer formed on the third electrode. It includes a vertical alignment layer.

A first polarizing plate having a polarization axis in a 45 ° direction or parallel to the rubbing axis of the first vertical alignment layer is disposed on a surface opposite to a surface on which the first electrode and the second electrode are formed on the first insulating substrate. A second polarizing plate having a polarization axis perpendicular to the polarization axis of the first polarizing plate is disposed on a surface opposite the surface on which the third electrode is formed.

The first electrode and the second electrode may be formed in an electrode structure of the FFS mode. In this case, the first electrode is formed on the first insulating substrate in a plate-like structure, the second electrode is formed on the first electrode with an insulating film therebetween, two or more arranged side by side at a predetermined interval It may include a branch portion and a connecting portion connecting the branch portion.

On the other hand, the first electrode and the second electrode may be formed in the electrode structure of the IPS mode. In this case, the first electrode is formed on the first insulating substrate, and includes two or more branches arranged side by side at a predetermined interval and a connecting portion connecting the branches, wherein the second electrode is formed between the insulating film. Two or more branches disposed at side by side with a predetermined distance and a connection part connecting the branches, wherein the branches of the first electrode and the branches of the second electrode alternate with each other. Can be deployed.

The liquid crystal molecules on the uneven pattern are vertically aligned when forming a positive vertical electric field between the first electrode and the second electrode and the third electrode, and are horizontally aligned when forming a negative vertical electric field. In addition, the liquid crystal molecules are vertically aligned when forming a negative vertical electric field between the first electrode and the second electrode and the third electrode, and are horizontally aligned when forming a positive vertical electric field.

12A and 12B are views schematically illustrating a liquid crystal arrangement state of the liquid crystal display according to the third embodiment of the present invention. 12A and 12B, when the vertical alignment layer having the uneven pattern is disposed on the lower substrate 100 and the horizontal alignment layer is disposed on the upper substrate 200, the surface having the bistable stability of the lower substrate 100 is provided. When the vertical alignment is performed, the liquid crystal 310 is initially in a horizontal aligned nematic (HAN) mode, and the horizontal bulk is vertically below the vertical bulk, and when the bistable surface of the lower substrate 100 is horizontally aligned. Liquid crystals are initially oriented horizontally below latitude and horizontally, such as in twisted nematic (TN) or electrically controlled birefringence (ECB) mode. Whether TN or ECB is determined by the uneven direction below.

Vertical switching with HAN-specific compensation films in HAN mode achieves wide viewing angles, while vertical viewing with HAN-specific compensation films in ECB mode enables narrow viewing angles. In addition, when using horizontal switching together with the HAN-only compensation film in HAN mode, wide viewing angle can be realized, and when using vertical switching together with the HAN-only compensation film in TN mode, narrow viewing angle can be realized.

The lower substrate of the liquid crystal display according to the present exemplary embodiment includes a first electrode and a second electrode forming a horizontal electric field, and are formed to have an uneven pattern on the first electrode and the second electrode, and have a rubbing axis in a predetermined direction. An alignment film is included. In addition, the upper substrate includes a first electrode, a third electrode forming a vertical electric field with the second electrode, and a horizontal alignment layer having a rubbing axis in a direction parallel or perpendicular to the rubbing axis of the vertical alignment layer formed on the third electrode. .

The liquid crystal display device may include a first polarization axis disposed on a surface opposite to a surface on which the first electrode and the second electrode are formed and having a polarization axis in a 45 ° direction or parallel to the rubbing axis of the vertical alignment layer. Polarizers; And a second polarizing plate disposed on a surface opposite to a surface on which the third electrode of the second insulating substrate is formed and having a polarization axis perpendicular to the polarization axis of the first polarizing plate.

The first electrode and the second electrode may be formed in an electrode structure of the FFS mode. In this case, the first electrode is formed on the first insulating substrate in a plate-like structure, the second electrode is formed on the first electrode with an insulating film therebetween, two or more arranged side by side at a predetermined interval It may include a branch portion and a connecting portion connecting the branch portion.

The first electrode and the second electrode may be formed in the electrode structure of the IPS mode. In this case, the first electrode is formed on the first insulating substrate, and includes two or more branches arranged side by side at a predetermined interval and a connecting portion connecting the branches, wherein the second electrode is formed between the insulating film. It is disposed insulated from the first electrode, and the two or more branches arranged side by side at a predetermined interval and the connecting portion for connecting the branch, wherein the branch portion of the first electrode and the branch portion of the second electrode alternately mutually Can be arranged.

The liquid crystal molecules on the uneven pattern are vertically aligned when the positive vertical electric field is formed between the first electrode and the second electrode and the third electrode, and are horizontally aligned when the negative vertical electric field is formed. In addition, the liquid crystal molecules on the uneven pattern are vertically aligned when the negative vertical electric field is formed between the first electrode and the second electrode and the third electrode, and are horizontally aligned when the positive vertical electric field is formed.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art or those with ordinary knowledge in the art, the spirit and scope of the present invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope thereof.

Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

FIG. 1 is a view schematically showing a liquid crystal arrangement state of a liquid crystal display according to a first embodiment of the present invention, in which liquid crystals are arranged in a splay state.

FIG. 2 is a view schematically showing a liquid crystal arrangement state of the liquid crystal display according to the first embodiment of the present invention, in which the liquid crystals are arranged in a twisted state by 180 °.

3 is a perspective view schematically showing a liquid crystal display according to a first embodiment of the present invention.

4 to 7 are views for explaining the operation principle of the liquid crystal display according to the first embodiment of the present invention. FIGS. 4 and 5 illustrate a wide viewing angle mode using horizontal switching in the splay state. 7 shows a narrow viewing angle mode using vertical switching in a 180 ° twist state.

8A and 8B show photographs horizontally switched in a splay state when the cell gap is 5 μm and the birefringence is 0.1.

9A and 9B show photographs vertically switched in a 180 ° twist state when the cell gap is 5 μm and the birefringence is 0.1.

10A and 10B are diagrams for explaining an arrangement state of liquid crystals in a vertical alignment film on which an uneven pattern is formed.

11A and 11B schematically illustrate a liquid crystal arrangement state of a liquid crystal display according to a second exemplary embodiment of the present invention.

12A and 12B are views schematically illustrating a liquid crystal arrangement state of the liquid crystal display according to the third embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: lower substrate 200: upper substrate

110: first insulating substrate 130: first electrode

140: insulating film 150: second electrode

150a: connection portion 150b: branch portion

170: first horizontal alignment layer 180: first polarizing plate

210: second insulating substrate 230: third electrode

270: second horizontal alignment layer 280: second polarizing plate

Claims (22)

A first insulating substrate, a first electrode and a second electrode formed on one surface of the first insulating substrate and forming a horizontal electric field between each other, and a first having a rubbing axis in a predetermined direction formed on the first electrode and the second electrode A lower substrate including a horizontal alignment layer; A third electrode disposed to face the lower substrate and formed on a second insulating substrate, a surface of the second insulating substrate and forming a vertical electric field with the first electrode and the second electrode, and formed on the third electrode; An upper substrate including a second horizontal alignment layer having a rubbing axis parallel to the rubbing axis of the first horizontal alignment layer; And And a liquid crystal layer interposed between the lower substrate and the upper substrate and including liquid crystal molecules. When the vertical electric field is removed between the first electrode and the second electrode and the third electrode and a horizontal electric field is formed between the first electrode and the second electrode, the liquid crystal molecules are arranged in a splay state and rotated according to the horizontal electric field adjustment. The angle is changed to operate in wide viewing angle mode, When the horizontal electric field is removed and a vertical electric field is formed between the first electrode, the second electrode, and the third electrode, the liquid crystal molecules are arranged in a twisted state, and the rotation angle is changed according to the vertical electric field adjustment to operate in the narrow viewing angle mode. Liquid crystal display characterized in that. The method of claim 1, A first polarizer disposed on a surface opposite to a surface on which the first and second electrodes of the first insulating substrate are formed, and having a polarization axis parallel to the rubbing axis of the first alignment layer; And A second polarizer disposed on a surface opposite to a surface on which the third electrode of the second insulating substrate is formed and having a polarization axis perpendicular to the polarization axis of the first polarizer; Liquid crystal display device further comprising. The method of claim 1, And the first electrode and the second electrode have an electrode structure in an FFS mode. delete The method of claim 1, And the first electrode and the second electrode have an electrode structure in an IPS mode. delete delete delete A first insulating substrate, a first electrode and a second electrode formed on one surface of the first insulating substrate and forming a horizontal electric field therebetween, and formed with a concave-convex pattern on the first electrode and the second electrode, and in a predetermined direction A lower substrate comprising a first vertical alignment layer having a rubbing axis of; A third electrode disposed to face the lower substrate and formed on a second insulating substrate, a surface of the second insulating substrate and forming a vertical electric field with the first electrode and the second electrode, and formed on the third electrode; An upper substrate including a second vertical alignment layer having a rubbing axis in a direction parallel or perpendicular to a rubbing axis of the first vertical alignment layer; And A liquid crystal layer interposed between the lower substrate and the upper substrate and including liquid crystal molecules; The liquid crystal molecules have a first array state and a second array state selected according to the inversion of the electric field direction of the vertical electric field between the first electrode, the second electrode, and the third electrode, wherein the first array state is the lower substrate. A liquid crystal molecule arranged vertically on the surface, the second arrangement state includes liquid crystal molecules arranged horizontally on the lower substrate surface, The liquid crystal molecules in the first array state and the liquid crystal molecules in the second array state are respectively rotated according to the horizontal electric field or the vertical electric field adjustment between the first electrode and the second electrode, so that the wide viewing angle mode or the narrow viewing angle mode. Liquid crystal display that operates exclusively. The method of claim 9, And the first alignment layer and the second alignment layer are vertical alignment layers. The method of claim 9, Wherein the first alignment layer is a vertical alignment layer, and the second alignment layer is a horizontal alignment layer. The method of claim 9, And the first electrode and the second electrode have an electrode structure in an FFS mode. delete The method of claim 9, And the first electrode and the second electrode have an electrode structure in an IPS mode. delete delete delete delete delete delete delete delete

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