KR20060006529A - LCD and its manufacturing method - Google Patents

Abstract

The present invention relates to a liquid crystal display device, comprising a common electrode layer formed on a first substrate material, the first substrate material, and having a first cutting pattern, and a conductive layer disposed between the first substrate material and the common electrode. A thin film transistor substrate comprising a color filter substrate including a second substrate material, a pixel electrode layer formed on the second substrate material, the pixel electrode layer having a second cutting pattern, and a thin film transistor switching the pixel electrode layer; And a liquid crystal layer positioned between the color filter substrate and the thin film transistor substrate. As a result, in the PVA mode liquid crystal display device, there is no need to coat the conductive layer on the polarizing plate, thereby reducing manufacturing cost and preventing occurrence of stains.

Description

Liquid crystal display and its manufacturing method {LIQUID CRYSTAL DISPLAY AND METHOD OF MANUFACTURING THE SAME}

1 is a cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention;

2A to 2F are cross-sectional views illustrating a method of manufacturing a color filter substrate according to a first embodiment of the present invention;

3 is a cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention.

Explanation of Signs of Major Parts of Drawings

Reference numeral 110: first substrate material 120a: black matrix 130: color filter layer 140: overcoat film 150: common electrode layer 151: second incision pattern

160: conductive particles

The present invention relates to a liquid crystal display device and a manufacturing method thereof. More specifically, the present invention relates to a liquid crystal display (PVA) and a method of manufacturing the same, wherein a conductive layer is disposed between the substrate material of the color filter substrate and the common electrode layer.

The liquid crystal display device includes a thin film transistor substrate on which a thin film transistor is formed, a color filter substrate on which a color filter layer is formed, and a liquid crystal panel on which a liquid crystal layer is positioned. Since the liquid crystal panel is a non-light emitting device, a backlight unit for irradiating light may be disposed on the rear surface of the thin film transistor substrate. Light transmitted from the backlight unit is adjusted according to the arrangement of the liquid crystal layer.

In addition, in order to drive each pixel of the liquid crystal panel, a driving circuit and a data driver and a gate driver for receiving a driving signal from the driving circuit and applying a voltage to the data line and the gate line in the display area are provided.

Such a liquid crystal display device is advantageous for thin, small size, and low power consumption, but has disadvantages in size, realization of full color, contrast enhancement, and wide viewing angle.

In order to compensate for the wide viewing angle, which is a disadvantage of the liquid crystal display, many researches such as multi-domain technology, phase compensation technology, IPS mode, VA mode, and optical path control technology have been applied. Further, PVA and SE (surrounding) combining partial etching slits of pixel electrodes and other techniques (e.g., cholesteric dopants, alignment control electrodes, orientation methods such as protrusions and rubbing) in VA mode, respectively. electrodes, ridge fringe field multidomain homeotropic (REFMH), and lateral field induced VA (LFIVA).                         

In the patterned vertically aligned (PVA) mode, an incision pattern is formed in each of the pixel electrode layer and the common electrode layer. It is a method of widening the viewing angle by controlling the direction in which the liquid crystal molecules lie down by using a fringe field formed by these incision patterns.

However, in the PVA mode, an incision pattern is formed in the common electrode layer, so that static electricity from the outside does not adequately escape to the outside of the liquid crystal panel. Static electricity that has not escaped to the outside may be applied to the liquid crystal layer, causing display quality defects.

Conventionally, in order to process such static electricity, a conductive layer including antimony tin oxide or the like is coated on a polarizing plate attached to a color filter substrate. However, when such a method is used, there is a problem that staining occurs easily by the conductive layer along with an increase in the unit cost due to the coating of the conductive layer.

Accordingly, an object of the present invention is to provide a PVA mode liquid crystal display device and a method of manufacturing the same, which do not require coating a conductive layer on a polarizing plate.

The above object is to provide a liquid crystal display device, comprising: a common electrode layer formed on a first substrate material, the first substrate material, and having a first cutting pattern; and a conductive layer disposed between the first substrate material and the common electrode layer. A thin film transistor substrate including a color filter substrate including a layer, a second substrate material, a pixel electrode layer formed on the second substrate material, and having a second cutting pattern, and a thin film transistor switching the pixel electrode layer; It is achieved by including a liquid crystal layer positioned between the color filter substrate and the thin film transistor substrate.

The conductive layer preferably includes a black matrix and a color filter layer imparted with conductivity.

The black matrix and the color filter layer preferably include conductive particles.

The black matrix is made of metal, and the color filter layer preferably includes conductive particles.

The conductive particles preferably include nickel balls.

According to another aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising: forming a conductive black matrix and a color filter layer on a substrate material, and forming a common electrode layer having a cutout pattern on the overcoat layer. It can be achieved by including the step of forming.

The method may further include forming an overcoat layer on the black matrix and the color filter layer, wherein the common electrode layer is formed on the overcoat layer.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention. The liquid crystal display is largely positioned between the color filter substrate 100a and the thin film transistor substrate 200 coupled to the color filter substrate 100a and between the color filter substrate 100a and the thin film transistor substrate 200. It is divided into the liquid crystal layer 300.

Although not shown, the LCD may further include a backlight unit, a driving circuit, an external casing, and the like disposed on the rear surface of the thin film transistor substrate 200.

First, the color filter substrate 100a will be described.

The black matrix 120a is formed on the first substrate material 110. The black matrix 120a generally distinguishes between RGB cells and serves to block direct light irradiation to the thin film transistor positioned on the thin film transistor substrate 200.

The black matrix 120a according to the first embodiment is made of a photosensitive organic material to which black pigment is added. As the black pigment, carbon black or titanium oxide is used. Here, the black matrix 120a includes the conductive particles 160, and the conductive particles 160 provide conductivity to the black matrix 120a.

The color filter layer 130 is formed by repeating RGB with the black matrix 120a as a boundary. The color filter layer 130 serves to impart color to light emitted from the backlight unit (not shown) and passed through the liquid crystal layer 130.

The color filter layer 130 is formed of a photosensitive organic material and includes conductive particles 160 like the black matrix 120a. The conductive particles 160 impart conductivity to the color filter layer 130.

Since the black matrix 120a and the color filter layer 130 formed on the color filter substrate 100a include the conductive particles 160, both are conductive. The black matrix 120a and the color filter layer 130 form a conductive layer 170a. The conductive layer 170a thus formed is positioned on the front surface of the color filter substrate 100a without a substantially cut pattern. Therefore, the static electricity from the outside is not applied to the liquid crystal layer 300 through the first cutting pattern 151, and is discharged to the outside of the color filter substrate 100a along the conductive layer 170a.

The conductive particles 160 have a metallic ball shape, and are preferably nickel balls. The amount of the conductive particles 160 added is appropriate in that the conductivity can be imparted to the color filter layer 130 while not degrading the transparency of the color filter layer 130. In addition, the conductive particles 160 are preferably small in diameter and uniform.

An overcoat layer 140 is formed on the black matrix 120a which is not covered by the color filter layer 130 and the color filter layer 130. The overcoat layer 140 serves to protect the color filter layer 130, and an acrylic epoxy material is commonly used.

The common electrode layer 150 is formed on the overcoat layer 140. The common electrode layer 150 is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The common electrode layer 150 directly applies a voltage to the liquid crystal layer 300 together with the pixel electrode layer 270 of the thin film transistor substrate. The first cutting pattern 151 is formed on the common electrode layer 150. The first cutout pattern 151 is a characteristic configuration of the PVA mode, and serves to divide the liquid crystal layer 300 into a plurality of domains together with the second cutout pattern 271 of the pixel electrode layer 270 which will be described later.

Next, the thin film transistor substrate 200 will be described.                     

Gate wiring is formed on the second substrate material 210. The gate wirings are a plurality of gate lines (not shown) extending in the horizontal direction, gate pads (not shown) connected to the ends of the gate lines to receive the gate signals from the outside, and transferred to the gate lines, and are part of the gate lines. A gate electrode 220 that is part of the transistor is included.

At this time, the gate wiring may be formed in a single layer, but may be formed in a double layer or a triple layer. In the case of forming a single layer, it may be made of aluminum or aluminum-neodynium alloy, and in the case of forming a double layer, the lower layer is formed of a material having excellent physicochemical properties such as chromium, molybdenum or molybdenum alloy film, and made of aluminum or aluminum alloy. The upper layer may be formed of a material having a low specific resistance, such as the like.

A gate insulating film 230 made of silicon nitride (SiNx) or the like is formed on the gate wiring.

A semiconductor layer 240 made of a semiconductor such as hydrogenated amorphous silicon is formed on the gate insulating layer 230. The semiconductor layer 240 overlaps the gate electrode 220.

On the semiconductor layer 240, contact layers 241 and 242 made of a material such as n + hydrogenated amorphous silicon, which are heavily doped with n-type impurities, are formed. The contact layer 241 is separated at both sides with respect to the gate electrode 220.

Data wirings are formed on the contact layers 241 and 242. The data line is connected to the source electrode 252 and the source electrode 252 formed on the source contact layer 241 and to one end of the data line 251 and the data line 251 extending in the vertical direction. And a data pad (not shown) receiving an image signal from the outside, and a drain electrode 253 positioned opposite to the source electrode 252 with respect to the gate electrode 220.

In this case, the data line may be formed of a single layer like the gate line, but may be formed of a double layer or a triple layer. In the case of forming a single layer, it may be made of aluminum or aluminum-neodynium alloy, and in the case of forming a double layer, an under layer made of a material having excellent physicochemical properties such as chromium, molybdenum or molybdenum alloy film is formed, and aluminum or aluminum An upper layer made of a material having a low specific resistance such as an alloy can be formed.

The protective film 260 is formed on the data line. The passivation layer 260 covers and protects the channel portion between the source electrode 252 and the drain electrode 253. In the first embodiment, the passivation layer 260 exposes not only the channel portion but also the drain electrode 253. All data lines are covered except for a contact hole (not shown) that exposes the data pad.

A pixel electrode layer 270 made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the passivation layer 260, and a pixel electrode layer (on the gate pad, the sustain electrode pad, and the data pad) is formed on the passivation layer 260. An auxiliary pad (not shown) made of the same material as 270 is formed. The second cutout pattern 271 is formed on the pixel electrode layer 270.                     

If the liquid crystal display device is a reflective type, the pixel electrode layer 270 may be made of a metal having good reflectance rather than a transparent conductive material.

The first cutting pattern 151 and the second cutting pattern 271 may be formed in various shapes. For example, both the first cutout pattern 151 and the second cutout pattern 271 may be formed diagonally and orthogonally to each other. In this case, the direction of the fringe field is evenly distributed in four directions.

The liquid crystal layer 300 is positioned between the color filter substrate 100a and the thin film transistor substrate 200. The liquid crystal molecules of the liquid crystal layer 300 are vertical in the length direction when no voltage is applied. When voltage is applied, the liquid crystal molecules lie perpendicular to the electric field because the dielectric anisotropy is negative. However, when the first incision pattern 151 and the second incision pattern 271 are not formed, the liquid crystal molecules are arranged randomly in various directions because the azimuth angles of the lying down are not determined, and the foreground lines at the boundary planes having different orientation directions. ) The first incision pattern 151 and the second incision pattern 271 form a fringe field when a voltage is applied to the liquid crystal layer 300 to determine the azimuth angle of the liquid crystal alignment. In addition, the liquid crystal layer 300 is divided into multiple regions according to the arrangement of the first cutting pattern 151 and the second cutting pattern 271.

2A to 2F are cross-sectional views illustrating a method of manufacturing the color filter substrate 100a according to the first embodiment of the present invention.

First, as shown in FIG. 2A, a black matrix 120a is formed on the first substrate material 110. The black matrix 120a is generally located above the gate line and the data line, and in some cases, the black matrix 120a may also be located above the first cutout pattern 151.                     

The process of forming the black matrix 120a is as follows. First, the black matrix and the conductive particles 160 are added to the photosensitive organic material to form a black matrix photoresist. Carbon black or titanium oxide may be used as the black pigment, and nickel balls may be used as the conductive particles 160. The black matrix composition is applied onto the first substrate material 110, exposed, developed, and baked to complete the black matrix 120a. The completed black matrix 120a includes conductive particles 160, thereby providing conductivity.

FIG. 2B shows that the color filter photosensitive liquid is applied to the upper portion of the first substrate material 110 on which the black matrix 120a and the black matrix 120a are not formed. The color filter photoresist is prepared by mixing the conductive particles 160 with a photosensitive organic material having any one color of RGB. The color filter layer 130 is manufactured by applying, exposing, developing, and baking the color filter composition.

2C shows that one color filter layer 130 of RGB is formed, and FIG. 2D shows a completed color filter layer 130 in which RGB is alternately formed. In manufacturing the color filter layer 130, each of the RGB may be exposed while moving the same mask.

2E shows that the overcoat layer 140 is further formed on the black matrix 120a and the color filter layer 130. The overcoat layer 140 serves to protect the color filter layer 130, and an acrylic epoxy material is commonly used.

When the common electrode layer 150 is formed on the overcoat layer 140, the color filter substrate 100a is completed as shown in FIG. 2E. The common electrode layer 150 is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). After the transparent conductive material is deposited on the overcoat layer 140 by the sputtering method, the first cutting pattern 151 is formed through development and etching. Although there is no limitation on the shape, density, and position of the first cutting pattern 151 of the common electrode layer 150, preferably, the common electrode layer 150 is formed under oxygen of 200 ° C. or higher before forming the first cutting pattern 151. Annealing to grow the common electrode layer crystals to enhance the film quality, improve the light transmittance and then form a pattern.

Unlike the above embodiment, it is also possible to omit the overcoat film 140 in some cases. In addition, a protrusion layer (column spacer or photo spacer) may be formed in place of the bead-shaped spacer introduced to maintain a cell gap, which is a gap between the color filter substrate 100a and the thin film transistor substrate 200. Preferably, the protrusion layer may be formed by forming a photosensitive organic material into a protrusion having a predetermined height on the black matrix 120a and then baking the same.

3 is a cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention. The differences from the first embodiment are as follows.

The black matrix 120b in the second embodiment does not include the conductive particles 160 unlike the first embodiment. Instead, the black matrix 120b is made of a conductive metal material. Specifically, the black matrix 120b includes a metal oxide layer 121 positioned below and a metal layer 122 positioned above.                     

As in the first embodiment, the conductive layer 170b includes the color filter layer 130 including the black matrix 120b and the conductive particles 160. The static electricity from the outside is not applied to the liquid crystal layer 300 through the first cutout pattern 151, and exits to the outside of the color filter substrate 100b along the conductive layer 170b.

The manufacturing method of the color filter substrate 100b according to the second embodiment is similar to the manufacturing method of the color filter substrate 100a according to the first embodiment. Referring to the manufacturing process of the different black matrix 120b in both embodiments is as follows.

The metal oxide layer 121 and the metal layer 122 are continuously deposited on the entire surface of the first substrate material 110. Preferably, a chromium oxide layer is used as the metal oxide layer 121 and a chromium layer is used as the metal layer 122. The metal oxide layer 121 and the metal layer 122 may be deposited by a sputtering method. Accordingly, the metal oxide layer 121 and the metal layer 122 are sequentially positioned on the first substrate material 110. Thereafter, the black matrix 120b is completed through a known phenomenon and an etching process. In the case of using chromium oxide and chromium, since chromium oxide is generally etched by the chromium etchant, it can be etched using the same etchant in the etching process.

Unlike the first embodiment, since the black matrix 120b itself includes the conductive metal layer 122, the conductive particles 160 do not need to be additionally introduced into the black matrix 120b.

According to the manufacturing method of the liquid crystal display device according to the present invention, there is no process change other than adding conductive particles to the black matrix photosensitive liquid and the color filter photosensitive liquid. Therefore, the existing process can be used as it is.

In the above embodiment, separate black matrices 120a and 120b are used, but the present invention may also be applied to a configuration in which the color filter layer 130 of an adjacent color serves as a black matrix.

As described above, according to the present invention, in the PVA mode liquid crystal display device in which the incision pattern is formed in the common electrode layer, static electricity from the outside can be appropriately processed without coating a separate conductive layer on the polarizing plate. As a result, cost is saved, and stains that may be caused by the conductive layer of the polarizing plate do not occur.

Claims (7)

In the liquid crystal display device, A color filter substrate comprising a first substrate material, a common electrode layer formed on the first substrate material and having a first cutting pattern, and a conductive layer disposed between the upper substrate material and the common electrode; A thin film transistor substrate comprising a second substrate material, a pixel electrode layer formed on the second substrate material, the pixel electrode layer having a second cutting pattern, and a thin film transistor switching the pixel electrode layer; And a liquid crystal layer disposed between the color filter substrate and the thin film transistor substrate. The method of claim 1, The conductive layer includes a black matrix and a color filter layer imparted with conductivity. The method of claim 2, And the black matrix and the color filter layer comprise conductive particles. The method of claim 2, The black matrix is made of metal, And the color filter layer comprises conductive particles. The method according to claim 3 or 4, And the conductive particles comprise nickel balls. In the manufacturing method of the liquid crystal display device, Forming a black matrix and a color filter layer imparted with conductivity on the substrate material; And forming a common electrode having an incision pattern on the overcoat layer. The method of claim 6, Forming an overcoat layer on the black matrix and the color filter layer; And the common electrode is formed on the overcoat layer.

Images