KR20090054194A - In-plane-switching mode liquid crystal display device and fabrication method thereof - Google Patents

Abstract

The present invention relates to a transverse electric field type liquid crystal display device capable of driving in a wide viewing angle mode and a narrow viewing angle mode. A liquid crystal display device according to the present invention comprises: a first substrate; A second substrate; Gate lines and data lines intersecting on the first substrate to define red, green, blue, and vision control subpixels; A thin film transistor disposed at an intersection of the gate line and the data line; A common electrode on the red, green, and blue subpixels, the pixel electrode being disposed, and a passivation layer disposed on the pixel electrode; A common electrode disposed in the field control subpixel, the pixel electrode being disposed on the pixel electrode, and having a plurality of spacer patterns formed to have a thickness higher than that of the passivation layer; A red, green, and blue color filter layer formed on the second substrate to correspond to the red, green, and blue subpixels of the first substrate, respectively; A white color filter layer formed on the second substrate to correspond to the subpixel for controlling the field of view of the first substrate; And a liquid crystal layer interposed between the first substrate and the second substrate.

LCD, spacer pattern, common electrode, pixel electrode, field of view control

Description

Transverse electric field type liquid crystal display device and its manufacturing method {In-Plane-Switching mode Liquid Crystal Display device and fabrication method

The present invention relates to a transverse electric field type liquid crystal display device capable of driving in a wide viewing angle mode and a narrow viewing angle mode.

Recently, the liquid crystal display device, which is one of the flat panel display devices that are continuously attracting attention, is a device for changing the optical anisotropy by applying an electric field to a liquid crystal that combines the liquidity and the optical properties of the crystal, which is applied to a conventional cathode ray tube. Compared with the low power consumption, small volume, large size, and high definition, it is widely used.

The LCD has a variety of modes depending on the nature of the liquid crystal and the structure of the pattern.

Specifically, TN mode (Twisted Nematic Mode) for arranging the liquid crystal directors to be twisted by 90 ° and controlling voltage by applying a voltage, and dividing one pixel into several domains to change the field of view angle of each domain. Multi-domain mode that realizes wide viewing angle, OCB mode (Optically Compensated Birefringence Mode) that compensates for the phase change of light according to the direction of light by attaching a compensation film to the outer peripheral surface of the substrate, and on one substrate In-plane switching mode in which two electrodes are formed in the liquid crystal to twist in parallel planes of the alignment layer, and the long axis of the liquid crystal molecules is vertically aligned with the alignment layer plane using a negative type liquid crystal and a vertical alignment layer. VA mode (Vertical Alignment) is various.

Among them, the transverse electric field type liquid crystal display device is generally composed of a color filter substrate (hereinafter referred to as an upper substrate) and a thin film array substrate (hereinafter referred to as a lower substrate) which are disposed to face each other and include a liquid crystal layer therebetween.

That is, a black matrix for preventing light leakage and a color filter layer of R, G, and B for implementing color on the black matrix are formed on the upper substrate.

The lower substrate includes gate wirings and data wirings defining unit pixels, switching elements formed at intersections of the gate wirings and data wirings, and a common electrode and a pixel electrode crossing each other to generate a transverse electric field.

However, the conventional transverse electric field type liquid crystal display device has an advantage of having a wide viewing angle. However, when a computer is used for personal reasons, such an advantage may cause a malfunction of privacy that may be infringed by neighboring people.

Thus, in the related art, a narrow viewing angle was realized by attaching a liquid crystal display panel for viewing angle control on the main liquid crystal display panel for security or privacy, causing excessive light leakage in the black state in the left and right viewing angle directions. In addition to additionally manufacturing a liquid crystal display panel for viewing angle control, there is a problem in that the thickness and weight of the product are more than doubled.

In particular, misalignment may occur when assembling the liquid crystal display panel and the main liquid crystal display panel for the field of view control, and when used in the wide viewing angle mode, the light incident from the backlight is further transmitted through the liquid crystal display panel for the field of view control. Since there is a problem that the front brightness can be significantly reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transverse electric field type liquid crystal display device and a method of manufacturing the same, which include a red, green, and blue subpixel and a view control subpixel, which facilitate the manufacturing process and improve security.

In addition, the present invention forms a spacer pattern on the subpixel for view control, and forms a common electrode on the spacer pattern to form a vertical vertical field between the common electrode and the pixel electrode, thereby selectively selecting the narrow viewing angle mode and the wide viewing angle mode. Another object of the present invention is to provide a liquid crystal display and a method of manufacturing the same.

In order to achieve the above object, a liquid crystal display device according to the present invention, the first substrate;

A second substrate; Gate lines and data lines intersecting on the first substrate to define red, green, blue, and vision control subpixels; A thin film transistor disposed at an intersection of the gate line and the data line; A common electrode on the red, green, and blue subpixels, the pixel electrode being disposed, and a passivation layer disposed on the pixel electrode; A common electrode disposed in the field control subpixel, the pixel electrode being disposed on the pixel electrode, and having a plurality of spacer patterns formed to have a thickness higher than that of the passivation layer; A red, green, and blue color filter layer formed on the second substrate to correspond to the red, green, and blue subpixels of the first substrate, respectively; A white color filter layer formed on the second substrate to correspond to the subpixel for controlling the field of view of the first substrate; And a liquid crystal layer interposed between the first substrate and the second substrate.

Method of manufacturing a transverse electric field type liquid crystal display device according to another embodiment of the present invention,

Providing a substrate; Forming gate lines and data lines on the substrate to define red, green, blue, and field of view subpixels; Forming a pixel electrode in the red, green, blue, and visual control subpixel regions; A passivation layer and a compensation layer are successively formed on the substrate on which the pixel electrode is formed, and a mask process is performed to remove the compensation layer of the red, green, and blue subpixel regions, while protecting the pattern and compensation of the passivation layer on the visual control subpixel region. Forming a spacer pattern composed of a layer pattern; And forming a common electrode having a plurality of slit structures in the red, green, and blue subpixel regions, and forming a common electrode on the spacer pattern of the visual control subpixel region.

As described in detail above, the present invention includes the red, green, and blue subpixels and the subpixels for view control to facilitate the manufacturing process and to improve security.

In addition, the present invention forms a spacer pattern on the subpixel for view control, and forms a common electrode on the spacer pattern to form a vertical vertical field between the common electrode and the pixel electrode, thereby selectively selecting the narrow viewing angle mode and the wide viewing angle mode. There is an effect that can be implemented.

The present invention is not limited to the above-described embodiments, and various changes can be made by those skilled in the art without departing from the gist of the present invention as claimed in the following claims.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. First, it should be noted that the same components or parts in the drawings represent the same reference numerals as much as possible. In describing the embodiments, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the gist of the embodiments.

In addition, in the description of the embodiments, each layer (film), region, pattern or structures may be on or below the "on / above / over / upper" of the substrate, each layer (film), region, pad or patterns. (down / below / under / lower) ", the meaning is that each layer (film), region, pad, pattern or structure is a substrate, each layer (film), region, pad or It may be interpreted as being formed in contact with the patterns, or may be interpreted as another layer (film), another region, another pad, another pattern, or another structure formed in between. Therefore, the meaning should be determined by the technical spirit of the invention.

Hereinafter, a transverse electric field type liquid crystal display device and a manufacturing method thereof according to the present invention will be described with reference to the accompanying drawings.

1 is a plan view illustrating pixels of a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention, and FIGS. 2A and 2B are cross-sectional views illustrating a wide viewing angle mode operation along the line II ′ of FIG. 1. 4A and 4B illustrate a wide viewing angle mode and a narrow viewing angle mode of a liquid crystal display according to the present invention.

The liquid crystal display according to the present invention includes a lower substrate 101, an upper substrate 201, and a liquid crystal layer 131 interposed therebetween, and includes a red sub-pixel (Pr) and a green sub. A pixel (green sub-pixel: Pg), a blue sub-pixel (Pb), and a viewing angle controlling sub-pixel (Pv) are provided.

In the upper substrate 201, the red subpixel Pr, the green subpixel Pg, and the blue subpixel Pb include red, green, and blue color filter layers 123, respectively, and the sub-view control sub The pixel Pv does not include the color filter layer, and only the overcoat layer 129 is formed between the black matrices 122.

In the lower substrate 101, the red subpixel, the green subpixel, the blue subpixel, and the view control subpixel are applied to the plurality of common electrodes 124 and the pixel electrode 117 disposed under the common electrode 124. The lateral electric field and the vertical electric field are generated according to the on-off of the voltage. In particular, in the visual control subpixel of the present invention, the pixel electrode 117 and the common electrode 124 are vertically spaced apart by the spacer pattern 116c to form a vertical electric field between the two electrodes.

In addition, when the field of view control subpixel is in an off state (black state), the liquid crystal display is driven in a wide viewing angle mode by the operation of the red, green, and blue subpixels. In the on-state (white state), the liquid crystal display generates light leakage at the side viewing angle and drives the narrow viewing angle mode.

When the liquid crystal display is driven in the narrow viewing angle mode, a data voltage that maintains a white state is continuously applied to the pixel electrode 117 formed in the viewing pixel subpixel area. A data voltage that maintains a black state is continuously applied to the pixel electrode 117 formed in the pixel region.

As shown in FIGS. 1, 2A, and 2B, the lower substrate 101 of the transverse electric field type liquid crystal display device according to the present invention includes a plurality of gate wirings arranged in a row on the first transparent substrate 111. Subpixels Pr, Pg, Pb, and Pv are defined by a plurality of data lines 115 intersecting the 112 and the gate lines 112, and the red, green, blue, and visual control subpixels Pr. , Pg, Pb, and Pv are formed at intersections of the two wires to switch voltages, and are connected to the common wire 125 parallel to the gate wire 112 and vertically connected to the unit pixel. A plurality of common electrodes Vcom electrodes 124 branched into each other and a pixel electrode 117 connected to the thin film transistor TFT are formed in a plate shape in the entire unit pixel area. 125a is a fringe electrode which is branched from the common wiring 125 and disposed in the pixel edge region.

In this case, as shown in FIGS. 2A and 2B, an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx) is deposited between the gate wiring 112 and the data wiring 115 by PECVD. The formed gate insulating layer 113 is further formed. In addition, the pixel electrode 117 is disposed on the gate insulating layer 113 in the form of a plate in units of subpixels Pr, Pg, Pb, and Pv.

An inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx), or BCB (Benzocyclobutene) or acryl (Acryl) is formed on the entire surface of the first transparent substrate 111 on which the pixel electrode 117 and the data line 115 are formed. An organic insulating material, such as a base material, is applied to form the protective film 116, which serves to planarize the surface and protect the pattern. In the view control sub-pixel Pv region, an additional protective layer 116 is further formed on the protective layer 116 and patterned to form a spacer including a protective pattern 116a and a compensation pattern 116b on the pixel electrode 117. Pattern 116c was formed. A plurality of common electrodes 124 are formed on the passivation layer 116 at predetermined intervals in the red, green, and blue subpixel regions, and in the field control subpixel region, the common electrodes are disposed on the spacer pattern 116c. 124 is formed.

Guide grooves 180 are formed in the region between the spacer patterns 116c of the subpixel region for view control so that the liquid crystal molecules 132 of the liquid crystal layer 131 may be vertically arranged. In addition, the height of the spacer pattern 116c is formed to have a height of half or more of the cell gap between the upper substrate 201 and the lower substrate 101. In addition, the width of the guide hole 180 is preferably designed to be the same as the electrode width of the common electrode 124.

In this case, the TFT may include a gate electrode 112a branched from the gate line 112, a gate insulating layer 113 formed on the entire surface including the gate electrode 112a, and an upper portion of the gate electrode 112a. A semiconductor layer 114 formed by sequentially depositing amorphous silicon (a-Si) and amorphous silicon (n + a-Si) ion-implanted with impurities into the gate insulating layer 113 of the gate insulating film 113 and branching from the data line 115. And the source / drain electrodes 115a and 115b formed on the edges of the semiconductor layer 114 to control the voltage applied to the unit pixel P.

The pixel electrode 117 is formed in each of the red, green, blue, and visual control subpixels, and is in electrical contact with the drain electrode 115b of the thin film transistor.

In addition, the gate wiring 112 and the data wiring 115 include copper (Cu), aluminum (Al), aluminum alloy (AlNd: AluminumNeodymium), molybdenum (Mo), chromium (Cr), titanium (Ti), and tantalum ( A low resistance metal such as Ta) and molybdenum-tungsten (MoW) may be formed, and the common wiring 125 and the fringe electrode 125a are formed simultaneously with the gate wiring 112.

However, the common electrode 124 and the pixel electrode 117 are transparent conductive materials having excellent light transmittance, such as indium tin oxide (ITO) or indium zinc oxide (IZO). It is formed using metal as a material.

That is, the common electrode 124 is formed of ITO or IZO, which is a transparent conductive film that transmits light, and is formed on the passivation layer 116 formed on the pixel electrode 117 in the red, green, and blue subpixel regions. In the field control subpixel, the pixel is formed on the spacer pattern 116c.

An end of the common electrode 124 is electrically connected to the common wiring 125 by the contact hole 119 to receive a voltage from the common wiring 125, and the pixel electrode 117 is a subpixel. The region is formed in a plate shape having a structure similar to that of the pixel region, and receives a data signal supplied from the data line 115 through the thin film transistor TFT.

As shown in FIGS. 2A and 2B, signals are not supplied to the red, green, and blue subpixels Pr, Pg, and Pb, and signals of a black state are continuously supplied to the visual control subpixel Pv. At this time, the display screen of the liquid crystal display device is in a black state. Thereafter, as shown in FIG. 2B, when a data signal is supplied to the red, green, and blue subpixels to display an image, and a black signal is continuously supplied to the visual control subpixel, the liquid crystal display device is continuously supplied. The display screen of is in the wide viewing angle mode.

2B illustrates a state in which a data signal is supplied to the red, green, and blue subpixels to generate an electric field in the pixel region. At this time, the control signal is supplied to the visual control subpixel so as to continuously maintain the black state. At this time, a signal for controlling the subpixel for visual field control is supplied through the data line 115.

 As illustrated in FIG. 2B, when the visual control subpixel is in a black state and is in the wide viewing angle mode, the wide viewing angle characteristic shown in FIG. 4A is obtained. As shown in the figure, it can be seen that the viewing angle is secured in a wide area.

3A and 3B are cross-sectional views illustrating the narrow viewing angle mode operation along the line II ′ of FIG. 1.

2A and 2B, the same components use the same reference numerals, and detailed description of the structure is omitted.

As shown in FIG. 3A, no signal is supplied to the red, green, and blue subpixels Pr, Pg, and Pb, and a signal in a white state is continuously supplied to the visual control subpixel Pv. After that, as shown in FIG. 3B, when the data signal is supplied to the red, green, and blue subpixels to display an image, and the white state signal is continuously supplied to the visual control subpixel, the display of the liquid crystal display device is displayed. The screen is in narrow viewing angle mode. As shown in the figure, an electric field is formed between the common electrode 124 and the pixel electrode 117 of the subpixel for view control, and is formed between the common electrode 124 and the pixel electrode 117 by the spacer pattern 116c. Vertical electric field is formed. Therefore, all of the liquid crystal molecules 132 are arranged in a direction perpendicular to the region of the guide groove 180 formed by the spacer pattern 116c. This is similar to the operation of liquid crystal molecules in the TN mode. That is, in the state lying horizontally, the liquid crystal molecules 132 stand in the vertical direction and transmit light.

However, in the red, green, and blue subpixel regions, since the common electrode 123 and the pixel electrode 117 are formed with a single passivation layer 116 interposed therebetween, a horizontal electric field is generated between the two electrodes to form the liquid crystal molecules 132. ) Is arranged in the horizontal direction.

Accordingly, a data signal is supplied to each of the red, green, and blue subpixels to form an electric field in the pixel area, and in the field control subpixel area, the state is turned on (white state), and thus the display image has a narrow viewing angle characteristic.

 As shown in FIG. 3B, when the sub-pixel for controlling the field of view is in the white state and is in the narrow viewing angle mode, the liquid crystal display is in the narrow viewing angle mode as shown in FIG. 4B. As shown in the figure, it can be seen that the viewing angle is secured in a narrower region than in FIG. 4A.

Therefore, the front viewing angle is generally white, but in the left and right viewing angle directions, the retardation is largely generated by the liquid crystal molecules 132 that rise in the viewing control subpixels, thereby reducing contrast. The right angle of view becomes worse, and the angle of view becomes narrower.

Therefore, the user can adjust the viewing angle to view the screen as desired.

This provides flexibility to the security range for the user of the liquid crystal display device, and can be used not only for one person, but also when using more than one person, the screen can be seen in high quality without any inconvenience and security can be secured.

Meanwhile, the transverse electric field type liquid crystal display device according to the present invention may have various arrangement forms with respect to the arrangement order of the red, green, and blue subpixels Pr, Pg, and Pb and the view control subpixel Pv. The red, green and blue subpixels and the view control subpixels may be arranged horizontally.

Therefore, the wide viewing angle mode and the narrow viewing angle mode for security may be driven respectively. To switch the wide viewing angle mode and the narrow viewing angle mode, the viewing angle mode switching uses a selection signal, and the selection signal When the wide viewing angle mode is selected, the viewing control subpixel Pv is turned off. When the narrow viewing angle mode is selected, the viewing control subpixel Pv is turned on.

5A to 5D are views illustrating a lower substrate manufacturing process of the liquid crystal display according to the present invention. 5A through 5D illustrate a manufacturing process along a region corresponding to line II ′ of FIG. 1, but also a process of forming a thin film transistor formed in a pixel region.

5A and 5B, when the gate wiring, the gate electrode, the common wiring, and the fringe electrode 125a are formed on the first transparent substrate 111, the gate insulating layer 113 is formed on the first transparent substrate ( 111) Form in all areas.

Thereafter, an ITO or IZO film, which is a transparent conductive film, is formed on the first transparent substrate 111, and then a pixel electrode 117 having a plate structure is formed in the subpixel region.

When the pixel electrode 117 is formed as described above, an amorphous silicon, a doped (N +, P +) amorphous silicon, and a metal film are formed on the first transparent substrate 111, and then the mask process is sequentially performed to each pixel area. The semiconductor layer (114 in FIG. 1) and the source / drain electrodes (115a and 115b in FIG. 1) of the channel layer and the ohmic contact layer are formed on the substrate. At this time, the data line 115 is also formed.

When the data line 115 is formed on the first transparent substrate 111 as described above, the protection layer 116 and the compensation layer 116 ′ made of the same material (organic or inorganic layer) as the protection layer 116 are formed. .

When the passivation layer 116 and the compensation layer 116 ′ are formed on the first transparent substrate 111 as described above, as illustrated in FIG. 5C, compensation of the red, green, and blue subpixel regions during the contact hole process is performed. The layer 116 ′ is removed and patterned in the subpixel area for view control to form the guide grooves 180. In this case, the passivation layer 116c including the passivation layer pattern 116a and the compensating pattern 116b is formed in the subpixel region for the field control while the passivation layer 116 and the compensation layer 116 ′ are patterned.

The guide groove 180 functions to allow the liquid crystal molecules to be erected in a vertical direction along the inside of the guide groove 200 when the liquid crystal molecules are rearranged by an electric field. This is because the height of the spacer pattern 116c is perpendicular between the common electrode 124 formed on the spacer pattern 116c and the pixel electrode 117 disposed under the common electrode 124. This is because an electric field is formed.

In addition, when forming the spacer pattern 116c as described above, a common hole (125 in FIG. 1) formed on the first transparent substrate 111 and a contact hole (119 in FIG. 1) are simultaneously formed for electrical contact. .

Then, as shown in FIG. 5D, a transparent conductive film such as ITO or IZO is formed on the first transparent substrate 111 on which the spacer pattern 116c and the protective film 116 are formed, and then a mask process is performed to perform red, Common electrodes 124 are formed in the green and blue subpixel regions, and common electrodes 124 are formed on the spacer pattern 116c, respectively.

Accordingly, an electric field in which the common electrode 124 and the pixel electrode 117 are vertically vertical is formed by the spacer pattern 116c so that the liquid crystal molecules are arranged in the vertical direction along the guide groove 180. do.

As described above, in the present invention, the red, green, and blue subpixels are distinguished from the visual control subpixels, and in the visual control subpixel region, the liquid crystal molecules are rotated by a vertical electric field unlike the other subpixel regions so that the wide viewing angle mode or the narrow viewing angle is achieved. Mod can be implemented.

1 is a plan view illustrating pixels of a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention.

2A and 2B are cross-sectional views illustrating a wide viewing angle mode operation along the line II ′ of FIG. 1.

3A and 3B are cross-sectional views illustrating the narrow viewing angle mode operation along the line II ′ of FIG. 1.

4A and 4B illustrate a wide viewing angle mode and a narrow viewing angle mode of a liquid crystal display according to the present invention.

5A to 5D are views illustrating a lower substrate manufacturing process of the liquid crystal display according to the present invention.

* Description of the symbols for the main parts of the drawings *

111: first transparent substrate 121: second transparent substrate

112: gate wiring 115: data wiring

117: pixel electrode 119: contact hole

122: black matrix 123: color filter layer

124: common electrode 125: common wiring

116c: spacer pattern 180: guide groove

Claims (7)

A first substrate; A second substrate; Gate lines and data lines intersecting on the first substrate to define red, green, blue, and vision control subpixels; A thin film transistor disposed at an intersection of the gate line and the data line; A common electrode on the red, green, and blue subpixels, the pixel electrode being disposed, and a passivation layer disposed on the pixel electrode; A common electrode disposed in the field control subpixel, the pixel electrode being disposed on the pixel electrode, and having a plurality of spacer patterns formed to have a thickness higher than that of the passivation layer; A red, green, and blue color filter layer formed on the second substrate to correspond to the red, green, and blue subpixels of the first substrate, respectively; A white color filter layer formed on the second substrate to correspond to the subpixel for controlling the field of view of the first substrate; And A transverse electric field liquid crystal display device comprising a liquid crystal layer interposed between the first substrate and the second substrate. The transverse electric field liquid crystal display device according to claim 1, wherein the common electrode is formed in a plurality of slits. The transverse electric field liquid crystal display device according to claim 1, wherein the common electrode of the field control subpixel is formed on the plurality of spare patterns, respectively. The transverse electric field liquid crystal display device according to claim 1, wherein the spacer pattern is formed to have a thickness higher than half of a cell gap between the first substrate and the second substrate. The transverse electric field liquid crystal display device according to claim 1, wherein a guide groove is formed between the spacer patterns to align the liquid crystal molecules of the liquid crystal layer in a direction perpendicular to the surface of the first substrate. The transverse electric field liquid crystal display device according to claim 1, wherein the white color filter layer is an overcoat layer formed on the second substrate. Providing a substrate; Forming gate lines and data lines on the substrate to define red, green, blue, and field of view subpixels; Forming a pixel electrode in the red, green, blue, and visual control subpixel regions; A passivation layer and a compensation layer are successively formed on the substrate on which the pixel electrode is formed, and a mask process is performed to remove the compensation layer of the red, green, and blue subpixel regions, while protecting the pattern and compensation of the passivation layer on the visual control subpixel region. Forming a spacer pattern composed of a layer pattern; And Forming a common electrode having a plurality of slit structures in the red, green, and blue subpixel regions, and forming a common electrode on the spacer pattern of the subpixel region for the field of view control. .

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