KR101056014B1 - Liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

In the liquid crystal display, when the black matrix of the edge portion does not have sufficient light blocking ability or a foreign substance or the like enters through the black matrix forming process, a pinhole is formed, light leakage occurs in the outer portion of the active area of the liquid crystal display. Problems degrading have occurred.

According to the present invention, a polarizing plate is formed by forming an outer electrode in a region where an edge black matrix is formed so as to pass through the liquid crystal layer without changing a phase of light passing through the liquid crystal layer by a voltage applied to the outer electrode and the upper common electrode. Provided is a liquid crystal display device which prevents light leakage in a black matrix forming region of the edge by preventing transmission.

COT, Border Black Matrix, Light Spring, Normally Black

Description

Liquid crystal display device and method of fabricating the same             

1 is an exploded perspective view of a general liquid crystal display device.

2 is a cross-sectional view of a general liquid crystal display device.

3 is a plan view showing a part of a planar structure of a liquid crystal display according to a first embodiment of the present invention;

4 is a cross-sectional view taken along line IV-IV of FIG. 3.

5A and 5B are diagrams illustrating light propagation in upper and lower polarizers and liquid crystal panels when voltage is not applied and when voltage is maximized, respectively, in the NW mode liquid crystal display device.

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

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

FIG. 8 is a view partially showing a planar structure of a liquid crystal display device according to still another modification of the first and second embodiments of the present invention; FIG.

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

100 liquid crystal display device 101 array substrate

103: gate wiring 110: gate electrode

113: gate pad electrode 120: semiconductor layer

125: data wiring 130: source electrode

132: drain electrode 135: data pad electrode

142: drain contact hole 150: pixel electrode

153: gate auxiliary pad electrode 154: data auxiliary pad electrode

157: outer electrode 158: voltage applied contact

171: color filter substrate 180a, 180b, 180c: red, green, blue color filter pattern

AA: active area DPA: data pad part

GPA: Gate pad portion P: Pixel area

SBMA: border black matrix area

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having an electrode structure for preventing light leakage in the outer portion and a manufacturing method thereof.

In recent years, as the society enters the information age, the display field that processes and displays a large amount of information has been rapidly developed, and recently, the thin film transistor (Thin) having excellent performance of thinning, light weight, and low power consumption has recently been developed. Film Transistor (TFT) type liquid crystal display (TFT-LCD) has been developed to replace the existing cathode ray tube (CRT).

The image realization principle of the liquid crystal display device uses the optical anisotropy and polarization property of the liquid crystal. As is well known, the liquid crystal has a thin and long molecular structure and optical anisotropy having an orientation in an array, and when placed in an electric field, the liquid crystal has an orientation of molecular arrangement depending on its size. This change is polarized. The liquid crystal display is an essential component of a liquid crystal panel formed by bonding an array substrate and a color filter substrate formed with pixel electrodes and common electrodes facing each other with the liquid crystal layer interposed therebetween. In addition, it is a non-light emitting device which artificially adjusts the arrangement direction of liquid crystal molecules through the electric field change between these electrodes and displays various images by using the light transmittance which is changed at this time.

Recently, the active matrix type, in which pixels, which are the basic units of image expression, are arranged in a matrix manner, and switching elements are arranged in each pixel, is independently noticed for its excellent resolution and video performance. In addition, thin film transistors (TFTs) are well known as TFT-LCDs (Thin Firm Transistor Liquid Crystal Display Devices).

As shown in FIG. 1, which is an exploded perspective view of a general liquid crystal display, the array substrate 10 and the color filter substrate 20 face to face with the liquid crystal layer 30 interposed therebetween. 10 includes a plurality of gate wirings 14 and the data wirings 16 arranged vertically and horizontally to define a plurality of pixel regions P, and the switching points of the two wirings 14 and 16 are switching elements. The thin film transistor T is provided and is connected in one-to-one correspondence with the pixel electrode 18 provided in each pixel region P. FIG.

In addition, in the upper color filter substrate 20 facing the array substrate, the gate wiring 14, the data wiring 16, the thin film transistor T, and the like are not displayed on the surface facing the array substrate 10. A grid-like black matrix 25 is formed around the pixel region P so as to cover an area, and is sequentially and repeatedly arranged to correspond to each pixel region P in the grid of the black matrix 25. Red, green, and blue color filter patterns 26 are formed, and a transparent common electrode 28 is provided over the black matrix 25 and the entire red, green, and blue color filter patterns 26.

2 is a cross-sectional view of a general liquid crystal display device.

As illustrated, in the array substrate 10, which is a lower substrate, a gate insulating film 50 is formed on the entire surface on the transparent substrate 12, and an active region AA displaying an image on the gate insulating film 50. In the non-display area, the data line 55, which is one of the wirings defining the pixel region P, is formed at a predetermined interval. The gate line GPA is disposed below the gate insulating film 50 in the non-display area. A gate pad electrode 47 connected to the substrate 14 is formed, and a passivation layer 60 is formed on the entire surface of the data line 55 and the exposed gate insulating layer 50. The pixel electrode 18 is formed for each pixel region P. As shown in FIG. In this case, the pixel electrode 18 is formed in each pixel area P of the active area AA. In the gate pad part GPA or the data pad part (not shown), the pixel electrode 18 is formed. A sub pad electrode 72 (not shown) is formed in contact with each of the pad electrodes 47 (not shown).

In addition, in the color filter substrate 10 that is the upper substrate facing the array substrate 10 described above, the active region AA has an opening corresponding to each pixel region P on the transparent substrate 22. The black matrix 25 is formed to correspond to the data line 55 and the gate line (not shown), and the black matrix 25 may be formed only at one outer side of the drawing, but the edge black matrix 24 may surround the active area AA. Is formed.

In addition, red, green, and blue color filter patterns (not shown) 26b and 26c are sequentially formed in the openings of the black matrix 25 in the active area AA, and the lower portion of the color filter pattern 26 is formed. The common electrode 28 is formed on the entire surface.

In addition, a liquid crystal layer is formed between the array substrate 10 and the color filter substrate 20 to form the liquid crystal layer 30, and the two substrates 10 and 20 are bonded to the active region AA. The seal pattern 42 for maintaining the panel state is provided in contact with the common electrode 28 and the protective layer 60 corresponding to the edge black matrix 24.

In the above-described configuration, the black matrix 25 and the edge black matrix 24 formed to block light emitted from a backlight unit (not shown) positioned below the array substrate 10, which is a lower substrate, are generally chromium. Metal materials such as (Cr) or black resins are formed using black resins. Recently, in order to regulate the environment and increase productivity, the black matrix is formed using black resins rather than metals such as chromium (Cr). Products are becoming commonplace.

However, the black matrix using the black resin is reduced in the ability to block light compared to the black matrix of the metal material, and in order to exhibit the light blocking ability of the black mattress made of the metal material, the thickness is thicker than the thickness of the black matrix of the metal material. Due to the formation of a black matrix having a thick thickness using the black resin, an increase in the level difference of the color filter pattern formed by overlapping with the thick black matrix is intensified, which ultimately increases the thickness of the liquid crystal panel. It becomes the thickening factor.

In addition, in a liquid crystal display for a TV which requires a higher luminance than a liquid crystal display used for a notebook and a monitor, light leakage may occur outside the active area of the liquid crystal panel when the black matrix of the edge portion does not have sufficient light blocking ability. There is a problem of lowering the display quality. Furthermore, when the black matrix is formed using the black resin, pinholes and the like are easily generated when the black resin is applied, and when such pinholes occur in the edge black matrix area, light leaks through the pinholes. This occurs and the display quality is lowered.

In order to solve the above-described problem, the present invention, when forming a black matrix using an organic material such as black resin in place of a metal material such as chromium, in the edge black matrix region formed around the active region, a pinhole or It is an object of the present invention to provide a liquid crystal display device capable of solving the problem of light leakage caused by the light blocking ability being lower than that of a metal such as chromium.

A liquid crystal display according to an embodiment of the present invention for achieving the above object includes a first substrate including an active region for displaying an image as a first feature, and a non-display region surrounding the active region; An outer electrode disposed around the active area in the non-display area; A second substrate facing the first substrate; A common electrode formed under the second substrate; A liquid crystal layer interposed between the first and second substrates; A seal pattern formed along an edge of the non-display area to bond the first and second substrates; And first and second polarizing plates provided on the outer surfaces of the first and second substrates.

A gate line and a data line formed on the first substrate and extending to the non-display area and defining pixel regions crossing each other in the active area; A switching element formed at an intersection point of the gate line and the data line; A protective layer formed over the switching element, the gate wiring and the data wiring; The display device further includes a pixel electrode contacting the switching element on the passivation layer and formed in each pixel area.

In addition, a first black matrix having an opening on the common electrode of the second substrate, the opening corresponding to each pixel area of the active area; A second black matrix bordering the active region; Further comprising a red, green, blue color filter pattern is formed repeatedly in the opening sequentially.

The liquid crystal display of the first aspect may further include gate wiring and data wiring formed on the first substrate so as to extend to the non-display region, and to define pixel regions crossing each other in the active region; A switching element formed at an intersection point of the gate line and the data line; A protective layer formed over the switching element, the gate wiring and the data wiring; A first black matrix having an opening corresponding to each pixel area on the passivation layer; A second black matrix bordering the active region on the passivation layer; Red, green, and blue color filter patterns sequentially formed in the openings; The red, green, and blue color patterns may be configured for each pixel area and further include a pixel electrode connected to the switching element.

In this case, the outer electrode is formed on the second black matrix.

The liquid crystal display device of the first aspect may further include gate lines and data lines formed on the first substrate so as to extend to the non-display area, and to define pixel areas crossing each other in the active area; A switching element formed at an intersection point of the gate line and the data line; A first black matrix covering the switching element, the gate wiring, and the data wiring; A second black matrix surrounding the active area in the non-display area; A red, green, and blue color filter pattern that is sequentially repeated in each pixel area on the basis of the first black matrix; A protective layer provided on an entire surface of the red, green, and blue color filter patterns; The pixel electrode further includes a pixel electrode connected to the switching element for each pixel region.

At this time, the outer electrode is characterized in that formed on the second black matrix.

The liquid crystal display of the first feature may further include a pad portion connected to an external driving circuit in a non-display area of the first substrate, and the pad portion may be formed in the pad electrode in the non-display area of the first substrate. In order to receive a voltage from the driving circuit, a contact pattern extending from the outer electrode is further provided.

The protective layer may be formed of an organic insulating material, and the first and second black matrices may be formed of black resin.

In addition, the first and second polarizing plates are disposed to have polarization axes perpendicular to each other, and are driven in a normally white mode. A voltage that has a maximum voltage difference between the outer electrode and the common electrode is applied to the outer electrode. And the light incident on the liquid crystal layer through the first polarizing plate does not pass through the second polarizing plate having a polarization axis perpendicular to the polarization axis of the first polarizing plate so that the outer electrode always maintains a normally black state in the forming region. It is characteristic to keep. At this time, the application of the voltage to the outer electrode is characterized in that the inversion driving is applied by alternately applying a voltage having a different polarity.

In addition, the first and second polarizing plates are disposed to have polarization axes parallel to each other, and are driven in a normally black mode. In this case, the common electrode is applied to the common electrode such that the voltage difference is 0V between the outer electrode and the common electrode. The voltage is applied to the outer electrode so that light incident on the liquid crystal layer through the first polarizing plate does not pass through the second polarizing plate having a polarizing axis parallel to the polarizing axis of the first polarizing plate, thereby maintaining a black state at all times. Is characteristic.

In addition, at least one recess is formed at a predetermined interval in a region corresponding to the seal pattern of the outer electrode.

In the method of manufacturing a liquid crystal display according to the present invention, a gate wiring and a data wiring are formed on an active region displaying an image and a first substrate on which a non-display region is defined at an edge of the active region to define a pixel region. Making a step; Forming a switching element at each intersection of the gate line and the data line in each pixel area; Forming a pixel electrode connected to the switching element in each pixel region in the active region, and forming an outer electrode surrounding the active region in the non-display region; Forming a common electrode on an inner surface of the second substrate facing the first substrate; Forming a liquid crystal layer between the first and second substrates; Bonding the first and second substrates to form a seal pattern at edges of the first and second substrates; And forming first and second polarizing plates on outer surfaces of the first and second substrates, respectively.

Forming a first black matrix on the second substrate corresponding to the boundary of each pixel region on the first substrate and a second black matrix bordering the active region on the outer electrode; The method may further include forming red, green, and blue color filter patterns that are sequentially repeated in the first black matrix corresponding to each pixel area, or first bordering each pixel area on the first substrate. Forming a black matrix and a second black matrix bordering the active region corresponding to the outer electrode; The method may further include forming red, green, and blue color filter patterns which are sequentially repeated corresponding to the pixel areas.

The forming of the outer electrode may further include forming one or more recesses having a predetermined interval in the outer electrode.

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

<First Embodiment>

3 is a plan view showing a part of a planar structure of a liquid crystal display according to a first embodiment of the present invention.

As shown, the liquid crystal display device 100 is divided into an active area AA that displays a large image and a non-display area around the active area AA, and the non-display area includes an external driving circuit again. Pads (DPA, GPA) and the active area (AA) for connecting to a printed circuit board (PCB) and the like border having a predetermined width and border with a black matrix (not shown) to prevent light from below It consists of a black matrix area (EBMA).

Although not shown in the drawings other than the gate wiring 103 and the data wiring 125 on the array substrate 101 corresponding to the edge black matrix region EBMA, various wirings for operating the liquid crystal display device 100 (not shown) For example, a Vcom wiring (not shown) is formed, and a seal pattern 195 is formed to bond the array substrate 101 and the color filter substrate 171 at a constant interval therebetween. It is.

In addition, an outer electrode 157 is formed on the array substrate 101 in the edge black matrix region EBMA as the most characteristic of the present invention.

In more detail, the planar structure of the liquid crystal display according to the present invention will be described. In the active area AA, the gate wiring 103 is formed in the horizontal direction, and the gate wiring 103 is the gate of the non-display area. A gate pad electrode 113 is formed at one end of the gate line 103 extending to the pad portion GPA and extending to the gate pad portion GPA.

In addition, the pixel area P is defined by crossing the gate line 103 in the active area AA, and the data line 125 is formed in the vertical direction, and the data line 125 has a data pad portion ( DPA), and a data pad electrode 135 is formed at one end thereof.

In the active region AA, a thin film transistor Tr, which is a switching element, is formed at a portion where the data line 125 and the gate line 103 cross each other, and the thin film transistor P is formed in each pixel region P. As shown in FIG. The pixel electrode 150 connected through the drain electrode 132 and the drain contact hole 142 of the Tr is formed.

In addition, although not shown in the drawing, red, green, and blue color filter patterns (not shown, 180b and 180c) are formed in the color filter substrate 171 corresponding to each pixel area P of the array substrate 101. An opaque organic layer between the color filter patterns (not shown, 180b and 180c) and the patterns (not shown, 180b and 180c), that is, an area corresponding to the gate line 103 and the data line 125. One of the materials, black resin (black resin) is formed of a black matrix (not shown).

Although not shown in the drawings, polarization axes are perpendicular to the outer surface of the array substrate 101 and the color filter substrate 171, that is, the lower surface of the array substrate 101 and the upper surface of the color filter substrate 171. As a structure, the 1st, 2nd polarizing plate (not shown) is formed.

In the above-described structure, the outer electrode 157 formed in the edge black matrix area EBMA is partially extended to the gate pad part GPA or the data pad part DPA, so that the gate pad electrode 113 or the data pad is as described above. As the electrode 135 is formed, the voltage application contact portion 158 is formed, so that the specific voltage can be applied from an external driving circuit like the pad electrodes 113 and 135.

Next, a cross-sectional structure taken along line IV-IV of FIG. 3 will be described with reference to FIG. 4.

First, the cross-sectional structure of the array substrate 101 as the lower substrate will be described. In the active region AA, the gate wiring 103 in FIG. 3 is formed on the first substrate 102, and each pixel region ( The gate electrode 110 branched from the gate wiring (not shown) is formed at P).

Next, a gate insulating layer 117 is formed on an entire surface of the gate line (not shown) and the gate electrode 110, and the gate electrode 110 corresponds to the gate electrode 110 on the gate insulating layer 117. A semiconductor layer 120 having a larger area and having an active layer 120a and an ohmic contact layer 120b is formed.

In addition, a data line 125 is formed on the gate insulating layer 117 to cross the gate line (not shown) in the active region AA. In each pixel area P, the data line 125 is formed in the data line 125. A source electrode 130 which branches and partially overlaps with one end of the ohmic contact layer 120b of the semiconductor layer 120, and is spaced apart from the source electrode 130 by a predetermined distance, and is separated from the ohmic contact layer 120b. A drain electrode 132 is formed in contact with the tip. In this case, the active layer 120a is exposed in the spaced apart regions of the source and drain electrodes 130 and 132. The sequentially stacked gate electrode 110, the gate insulating layer 117, the semiconductor layer 120, and the source and drain electrodes 130 and 132 constitute a thin film transistor Tr as a switching element.

Next, a protective layer 140 made of an organic insulating material such as benzocyclobutene (BCB) or photo acryl is formed on the entire surface of the thin film transistor Tr and the data line 125. In this case, the protective layer 140 includes a drain contact hole 142 and a pad contact hole 144 (143 of FIG. 3), so that the lower drain electrode 132, the gate pad electrode 113, and the data pad electrode (not shown). H) are exposed respectively.

Next, a pixel electrode 150 in contact with the drain electrode 132 through the drain contact hole 142 as a transparent conductive material is formed in each pixel area P of the active area AA on the passivation layer 140. In the gate and data pad part GPA (DPA of FIG. 3), the auxiliary pad electrode 153 (154 of FIG. 3) is used to prevent corrosion of the exposed pad electrode 113 (135 of FIG. 3). It is formed in contact with the pad electrode 113 (135 of FIG. 3) through the pad contact hole 144 (143 of FIG. 3). In addition, an area between the pad part GPA (DPA of FIG. 3) and the active area AA, more precisely, an edge black matrix 175 of the color filter substrate 171, which is an upper substrate surrounding the active area AA, is formed. In the region on the array substrate 101 corresponding to the formed edge black matrix region EBMA, the pixel electrode 150 and the auxiliary pad electrode 153 (154 of FIG. 3) are formed of the same material, and the outer electrode 157 is formed on the same layer. ) Is formed. The use of the outer electrode 157 will be described after explaining the cross-sectional structure of the upper color filter substrate.

Next, in the color filter substrate 171, which is an upper substrate, the color filter substrate 171 corresponds to an area where a gate wiring (not shown), a data wiring 125, and a thin film transistor Tr are formed on the array substrate 101 under the transparent substrate 172. The black matrix 173 is formed, and the edge black matrix 175 is formed outside the active area AA by enclosing the active area AA with a predetermined width. In addition, the openings formed between the black matrices 173 in the active area AA, that is, the areas corresponding to the pixel areas P of the array substrate 101 are sequentially repeated red, green, and blue color filter patterns 180a, 180b and 180c overlap with the upper black matrix 173 and are partially formed. In addition, a common electrode 185 is formed on the entire surface under the red, green, and blue color filter patterns 180a, 180b, and 180c.

Next, the liquid crystal layer 190 is formed in the spaced apart regions of the array substrate 101 and the color filter substrate 171 facing each other, and the two substrates 101 and 171 have a border black matrix 175 formed thereon. The liquid crystal layer 190 is encapsulated without leaking to the outside by the seal pattern 195 provided in the region EBMA, and the two substrates 101 and 171 are bonded to each other to maintain a panel state.

In addition, a first polarizing plate 163 is provided on an outer surface of the liquid crystal display device 100, that is, a lower surface of the array substrate 101, and a second polarizing plate 188 is provided on an upper surface of the color filter substrate 171. At this time, the first and second polarizing plates 163 and 188 are characterized in that the polarization axis is provided so as to have a structure perpendicular to each other.

Next, although not shown in the drawing, in the active region AA, the pixel electrode 150 and the exposed protective layer 140 of the array substrate 101 and the common electrode 185 of the color filter substrate 171 are disposed. First and second alignment layers (not shown) are formed below the backlight unit, and a backlight unit (not shown) includes various optical sheets (not shown) and lamps (not shown) under the first polarizing plate 163. It is provided.

In the structure of the liquid crystal display device 100 of the present invention described above, the most characteristic is that the outer electrode 157 is formed on the protective layer 140 in the array substrate 101 corresponding to the edge black matrix region EBMA. will be. In this case, a part of the outer electrode 157 extends to the data pad part (not shown) or the gate pad part (GPA) in the form of a wire and is formed in the same shape as the pad electrode 113 (not shown). A specific voltage may be applied from a PCB (not shown) attached to a GPA (not shown).

Accordingly, an electric field is formed when the liquid crystal display device 100 is driven by the common electrode 185 formed in the color filter substrate 171 and the outer electrode 157 formed in the array substrate 101. Light passing through the first polarizing plate 163 from the bottom phase of the liquid crystal layer 190 is arranged so that the liquid crystal molecules in the liquid crystal layer 190 positioned between 157 and 185 are specifically arranged by the applied voltage. The light is passed through the edge black matrix 175 through the pinhole of the edge black matrix 175 such that the light does not pass through the second polarizing plate 188, that is, the black matrix region ( EBMA) is always kept black to prevent light leakage.

The liquid crystal display has a normally black mode (hereinafter referred to as NB mode) and a normally white mode (hereinafter referred to as NW mode), and the difference between the NB mode and the NW mode is the lower portion of the array substrate. And the angles of installation of the first and second polarizing plates provided on the color filter substrate, respectively. When the polarization axes of the first and second polarizing plates are arranged to be perpendicular to each other, the NW mode is arranged. In general, the NW mode is excellent in terms of luminance, so that a typical liquid crystal display device is almost manufactured in NW mode.

Here, the movement of the liquid crystal due to the application of voltage in the NW mode liquid crystal display device and the light propagation accordingly will be described for a while.

FIG. 5A illustrates the progress of light in the upper and lower polarizers and the liquid crystal panel when no voltage is applied in the NW mode liquid crystal display. FIG. 5B illustrates the upper and lower polarizers and the liquid crystal panel when the maximum voltage is applied. This is a diagram showing the progress of light in.                     

As shown in FIG. 5A, when the liquid crystal display device operating in the NW mode does not apply a voltage, when the light from the backlight unit (not shown) passes through the lower polarizing plate 415, the first polarization axis 417 may be used. Since only light vibrating in parallel to the first polarization axis 417 passes through the lower substrate 410 and enters the liquid crystal layer 470, no voltage is applied to the liquid crystal layer 470. The polymer chain of the alignment layer (not shown) has almost no inclination angle due to the encapsulation energy of the alignment layer (not shown) by the alignment layer (not shown) provided on the inner side of the liquid crystal panel. In this arranged direction, the state is almost lying, and the encapsulation energy becomes smaller toward the center of the liquid crystal layer, so that the inclination angle is almost perpendicular to the alignment layer. At this time, the liquid crystals near the first alignment layer (not shown) of the lower substrate 410 and the liquid crystals near the second alignment layer (not shown) of the upper substrate 450 are polarization axes 417 and 457 of each polarizer 415 and 455. Since the light is incident in the liquid crystal layer 470 having the above-described structure, the light is incident on the liquid crystal layer 470 to rotate along the liquid crystal, thereby causing a phase change. When reaching 455, since the light vibrates in a direction parallel to the second polarization axis 457 of the second polarizing plate 455, the light passes through the second polarization axis and thus displays a white state.

On the other hand, as shown in FIG. 5B, when the maximum voltage (Vmax) is applied to the liquid crystal display, the inclination angles of all liquid crystal molecules in the liquid crystal layer 470 are perpendicular to the first and second alignment layers (not shown). When the light passing through the first polarizing plate 415 of the lower substrate 410 enters the liquid crystal layer 470 arranged in this state, the first polarizing plate 415 of the first polarizing plate 415 is not changed in phase. It passes through the first polarization axis 417 and passes through the liquid crystal layer 470, and the light passing through the liquid crystal layer 470 passes through the first polarization axis 417 in the drawing. Since the light vibrates parallel to the polarization axis 417, the light may not pass through the second polarization plate 455 having the second polarization axis 457 perpendicular to the first polarization axis 417 of the lower first polarization plate 415. It will stay black.

At this time, it is preferable to alternately apply + and-to the maximum voltage to the outer electrode. In order to prevent deterioration of a liquid crystal, a liquid crystal display typically adopts an inversion driving method, for example, a line inversion, a dot inversion, or a frame inversion driving method by applying a voltage having a different polarity periodically. In addition, it is preferable to perform inversion driving to the outer electrode by periodically changing a voltage having the same absolute value and the opposite polarity with respect to the upper common voltage.

In the present invention, when the liquid crystal display device is driven in the NW mode, the maximum voltage for driving the liquid crystal display device is always applied to the outer electrode formed on the array substrate and the common electrode under the upper color filter substrate. When a voltage is applied to the outer electrode, an electric field is formed in the two electrodes so that the liquid crystal is positioned in a long line in the traveling direction of the light so that the light polarized by the lower polarizer plate passes through the liquid crystal layer without a phase change. The lower polarizing plate and the polarizing axis reach the upper polarizing plate formed vertically in the state of the light vibrating in the direction of the lower polarizing axis, which does not change, thereby preventing passing through the upper polarizing plate to maintain the constant black state. Therefore, it is possible to completely prevent light leakage in the edge black matrix forming region.

In the first exemplary embodiment of the present invention, an outer electrode is formed on an array substrate corresponding to the black matrix forming unit, and a maximum voltage for driving the liquid crystal is applied from a driving circuit through a pad unit to drive the liquid crystal display. The light passing through the liquid crystal layer is prevented from passing through the liquid crystal layer due to the normal black state, i.e., the maximum voltage difference between the common electrode and the outer electrode. When the light reaches the light beam, the light passes through the polarization axis of the lower polarizing plate as it is, that is, light having the characteristic of vibrating in a direction perpendicular to the polarization axis in the upper polarizing plate without phase change, so the light in this state does not transmit through the upper polarizing plate. In order to maintain the black state, thereby preventing It is due to a hole or a light blocking ability of OD (optical density) value is low correct the problem that light leakage occurs.

In the black matrix formed between the pixel areas in the active area, even though a pinhole occurs, light is emitted mainly from the surrounding pixel areas, so the surroundings are bright. In the case of the black matrix, the width of formation is more than a few mm, so the surroundings remain black. However, when light leakage occurs due to a pinhole, the black matrix is immediately recognized, which greatly affects the display quality. Therefore, the liquid crystal display device according to the first embodiment of the present invention can solve the problems mentioned in the prior art by effectively preventing the generation of light leakage in the edge portion outside the active area.                     

In the above-described structure, referring to FIG. 3, the outer electrode 157 is positioned on the passivation layer 140, and the gate pad part GPA or the data pad is disposed in the active area AA under the passivation layer 157. Gate (link) wiring (not shown) or data (link) wiring (not shown) extending to a negative portion (not shown) and other wiring for driving, for example, Vcom wiring (not shown), etc. are formed. The parasitic capacitance is generated by forming a capacitor between the outer electrode 157, the gate link wiring (not shown), the data link wiring (not shown), and a protective layer 140 therebetween, thereby generating the gate wiring (not shown). ) Or the data wiring 125, which may cause problems such as signal delay. Thus, the protective layer 140 may be benzocyclobutene (BCB) or photo acryl, which is an organic insulating material having a low dielectric constant. Formed from materials selected from It is preferred, and such a case may be formed to have a high aperture ratio structure formed so as to overlap the pixel electrode 150 and the gate wiring (not shown) and data line (125).

&Lt; Embodiment 2 >

The first embodiment described above relates to a liquid crystal display device having a general array substrate, a color filter substrate, and a liquid crystal layer interposed between the two substrates. In the second embodiment of the present invention, a switching element and a color are applied to the array substrate. The present invention relates to a color filter on TFT (COT) structure liquid crystal display, in which all filter layers are formed.

The most characteristic part of the present invention is to form an outer electrode in an area corresponding to the edge black matrix outside the active area so that the area is always black when the LCD is driven. In this case, the outer electrode is Since the parasitic capacitance is formed by overlapping the gate or data line extending to the gate pad portion or the data pad portion, the protective layer is formed of an organic insulating material having a low dielectric constant to prevent this. However, even when the protective layer is formed of an organic insulating material having a low dielectric constant, a small parasitic capacitance is formed, and in order to make it small enough so as not to affect the gate wiring or the data wiring, there is a problem that the thickness of the protective layer must be formed thick. .

However, the second embodiment of the present invention provides a liquid crystal display device having a structure having a sufficiently small parasitic capacitance of the outer electrode and the gate wiring or the data wiring without increasing the thickness of the protective layer.

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

As illustrated, the first substrate 202, which is the lower substrate 201, includes the thin film transistor Tr as a switching element to cover the thin film transistor Tr and to form an organic insulating material such as benzocyclobutene (BCB). Alternatively, a passivation layer 240 made of one of photo acryl is formed on the front surface, and red, green, and blue color filter patterns 280a, 280b, and 280c are formed on each pixel area P on the passivation layer 240. ) Are sequentially formed repeatedly. In this case, a black matrix 273 is formed in an area corresponding to each data line 225 or a gate line (not shown) between the passivation layer 240 and the red, green, and blue color filter patterns (not shown, 280b and 280c). Is formed, and an edge black matrix 275 having a predetermined width surrounding the active area AA is formed on the protective layer 240 outside the active area AA.

Further, in the active area AA, the thin film transistor Tr and the drain contact hole 242 are disposed on the red, green, and blue color filter patterns (not shown, 280b and 280c) in each pixel area P. A pixel electrode 250 is formed in contact with each other, and an upper portion of the color filter pattern 280 overlapping the edge matrix matrix 275 and an outside of the color filter pattern 280 are formed in the edge black matrix area EBMA. The outer electrode 257 is formed on the edge black mattress 275 exposed by the same material as the pixel electrode 250. In this case, the outer electrode 257 is formed on the edge black matrix 275 formed of the protective layer 240 and the black resin on the upper portion thereof, so that the distance between the lower gate or the data line (not shown) is lower than that of the first embodiment. The thickness of the black resin is further increased by at least the edge black matrix thickness of the black resin than that formed on the upper portion of the protective layer, and this difference in distance has the same effect as thickening the thickness of the protective layer in the first embodiment.

The black matrix can prevent the signal delay of the wiring due to parasitic capacitance even if the material forming the material has a high resistance and a low dielectric constant, even when the lower protective layer is formed to a thin thickness.

Accordingly, in the liquid crystal display device according to the second embodiment of the present invention having the above-described structure, the gate line (not shown) and the data line 225 are hardly affected by the parasitic capacitance, and the outer electrode ( The light passing through the liquid crystal layer 290 from the lower portion passes through the liquid crystal layer 290 without changing the phase by applying a voltage that drives the liquid crystal to the maximum by the common electrode 285 257 and the upper portion. The display quality can be improved by preventing the upper second polarizer 288 from passing through the pinhole (not shown) in the black matrix 275.

7 is a cross-sectional view of a liquid crystal display device having a COT structure, showing a modification of the second embodiment of the present invention.

All components including the outer electrode are the same as the COT structure liquid crystal display device of the second embodiment of FIG. 6 described above, and only red, green, and blue color filters sequentially formed for each pixel area are provided under the protective layer. It is characterized by being located. At this time, the protective layer is characterized in that to form a planarization film that serves as a step compensation of the red, green, blue color filter pattern of the lower.

The structure thereof will be described in detail. First, the first substrate 301, which is a lower substrate, includes a gate wiring (not shown) and a data wiring 325 defining a pixel region P on the transparent substrate 302. The thin film transistor Tr, which is a switching element, is formed at an intersection point of the gate line (not shown) and the data line 325. In the pad part GPA (not shown), the gate pad electrode 313 and the data are formed. A pad electrode (not shown) is formed. In the active region AA, a black matrix 373 is formed covering the gate wiring (not shown), the data wiring 325, and the thin film transistor Tr. In addition, an edge black matrix 375 is formed on the edge black matrix area EBMA outside the active area AA in which the pixel area P is defined and surrounds the active area AA. In this case, the edge black matrix 375 is characterized in that formed of a black resin (black resin).

In addition, red, green, and blue color filter patterns 380a, 380b, and 380c are sequentially formed in each pixel area P exposed to the outside of the black matrix 373 in the active area AA. The protective layer 340 is formed on the entire surface of the substrate 302 including the red, green, and blue color filter patterns 380a, 380b, and 380c.

The color filter pattern (the green color filter pattern 380b in the drawing) corresponding to the drain electrode 332 of the thin film transistor Tr in each pixel region P and the protective layer 340 thereon are drain contact holes 342. ) Is provided to expose the drain electrode 332, and the pixel electrode 350, which contacts the drain electrode 332 through the drain contact hole 342, is formed on each pixel area (top) of the passivation layer 340. It is formed every P). In addition, an outer electrode 357 is formed in the edge black matrix area outside the active area AA that displays an image using the material on which the pixel electrode 350 is formed, corresponding to the edge black matrix 375.

In addition, in the pad part GPA (not shown), a pad contact hole 344 (not shown) is provided in the protective layer 340 to expose each pad electrode 313 (not shown), and the pixel electrode 350 An auxiliary pad electrode 353 (not shown) contacting the pad electrode 313 (not shown) is formed through the pad contact hole 344 (not shown).

Next, in the second substrate 371, which is an upper substrate, a common electrode 385 is formed on the entire lower surface of the transparent substrate 372, and liquid crystal is formed between the first substrate 301 and the second substrate 371. The liquid crystal layer 390 is interposed therebetween, and the interposed liquid crystal is encapsulated between the outer electrode 357 and the common electrode 385 so that the first and second substrates 301 and 371 have a suitable gap. A seal pattern 395 is formed to maintain the state of the panel while being adhered to each other.

Also in the above-described liquid crystal display of the COT structure, in the edge black matrix forming region (EBMA) having the outer electrode 357 to which a voltage for always inducing a black state is applied when the liquid crystal display 300 is driven, Due to the characteristic of the COT structure, the black is disposed above the gate line (not shown) (see 103 in FIG. 3) or the data line 325 (see 125 in FIG. 3) extending from the active region AA to the pad portion GPA (not shown). The black matrix 357 of the resin and the protective layer 340 is formed on the upper portion, and the outer electrode 357 is formed on the protective layer 340, so that the protective layer 340 is not thickly formed. Even if the black resin 357 is formed by further stacking the edge black matrix 357, the distance between the outer electrode and the gate or data wiring is increased so that the gate wiring (see 103 in FIG. 3) or the data wiring (FIG. 3). To 125) Only parasitic doses low enough to have little effect will be present. In this case, the black matrix 357 may form a thinner thickness of the protective layer 340 as the material forming the material has a higher resistance and a lower dielectric constant, and may cause a signal delay phenomenon of the gate wiring or the data wiring due to parasitic capacitance. It can prevent. Accordingly, when the liquid crystal display 300 is driven by the outer electrode 357 and the common electrode 385 on the upper side, a maximum voltage for driving the liquid crystal is applied to the outer electrode 357 so that a backlight unit (not shown) is provided. Light passing through the first polarizing plate 363 below the first substrate 301 passes through the liquid crystal layer 390 without a phase change, and thus the second polarizing plate 388 above the second substrate 371. It prevents the light leakage in the edge black matrix area (EBMA) by maintaining the black state by not passing through.

According to the present invention, the outer electrode is formed in a general liquid crystal display device as in the first embodiment, or the parasitic capacitance due to the outer electrode is effectively reduced or protected while the outer electrode is formed as in the second embodiment. Although the COT structure liquid crystal display device does not need to form a thick layer separately, the present invention is not limited to the liquid crystal display device according to this embodiment, and it is obvious that the present invention can also be applied to a TFT on color filter (TOC) structure liquid crystal display device. Various changes and modifications are possible without departing from the spirit of the invention.

In the first and second embodiments and modified examples of the present invention, a liquid crystal display device for driving normally white driving by configuring the polarization axes of the first and second polarizers to be perpendicular to each other is described as an example. In the liquid crystal display device operating in the normally black mode by providing the polarization axes in parallel, the outer electrode is formed in the edge black matrix region as in the first and second embodiments and the modifications described above, and the The black state can be maintained by receiving the same voltage as the common electrode, that is, the common voltage, through the voltage applying contact portion formed to extend to the pad portion.

In addition, in the above-described first and second embodiments and modified examples, a seal pattern is formed on the outer electrode formed of the transparent conductive material, and according to the first and second embodiments of the present invention, Referring to FIG. 8 (parts the same as in FIG. 3, the same reference numerals are shown), a portion of the seal pattern (not shown) may be used to improve contact characteristics between the outer electrode 157 and the seal pattern 195. In the outer electrode 157 of the portion where the 195 is formed, the concave portion 159 is formed at a predetermined interval to improve contact characteristics between the outer electrode 157 and the seal pattern 195.

In the liquid crystal display according to the present invention, the liquid crystal layer is formed without changing the phase of light passing through the liquid crystal layer by a voltage applied to the outer electrode and the upper common electrode by forming the outer electrode in the region where the edge black matrix is formed. By passing through the polarizing plate, it is possible to prevent the light leakage in the black matrix forming region of the edge.

In addition, even if a black matrix is formed using a black resin having a light blocking ability that is lower than a metal material such as chromium, it is not necessary to form a thick black matrix to increase the light blocking ability, thereby reducing manufacturing costs.

Claims (21)

A first substrate comprising an active area for displaying an image and a non-display area surrounding the active area; An outer electrode disposed around the active area in the non-display area; A second substrate facing the first substrate; A common electrode formed under the second substrate; A liquid crystal layer interposed between the first and second substrates; A seal pattern formed around the active region to bond the first and second substrates; First and second polarizing plates provided on outer surfaces of the first and second substrates. Liquid crystal display comprising a. The method of claim 1, A gate wiring and a data wiring formed on the first substrate and extending to the non-display area, and defining pixel regions crossing each other in the active region; A switching element formed at an intersection point of the gate line and the data line; A protective layer formed over the switching element, the gate wiring and the data wiring; A pixel electrode formed in each pixel region in contact with the switching element on the protective layer; Liquid crystal display further comprising. The method of claim 2, A first black matrix having an opening on the common electrode of the second substrate, the opening corresponding to each pixel area of the active area; A second black matrix surrounding the active region; Red, green, and blue color filter patterns sequentially formed in the openings Liquid crystal display further comprising. The method of claim 1, A gate wiring and a data wiring formed on the first substrate and extending to the non-display area, and defining pixel regions crossing each other in the active region; A switching element formed at an intersection point of the gate line and the data line; A protective layer formed over the switching element, the gate wiring and the data wiring; A first black matrix having an opening corresponding to each pixel area on the passivation layer; A second black matrix surrounding the active region over the protective layer; Red, green, and blue color filter patterns sequentially formed in the openings; A pixel electrode configured for each pixel region on the red, green, and blue color filter patterns and connected to the switching element Liquid crystal display further comprising. The method of claim 4, wherein And the outer electrode is formed on the second black matrix. The method of claim 1, A gate wiring and a data wiring formed on the first substrate so as to extend to the non-display area and define a pixel area crossing each other in the active area; A switching element formed at an intersection point of the gate line and the data line; A first black matrix covering the switching element, the gate wiring, and the data wiring; A second black matrix surrounding the active area in the non-display area; A red, green, and blue color filter pattern that is sequentially repeated in each pixel area with respect to the first black matrix; A protective layer provided on an entire surface of the red, green, and blue color filter patterns; A pixel electrode connected to the switching element for each pixel region on the passivation layer; Liquid crystal display further comprising. The method of claim 6, And the outer electrode is formed on the second black matrix. The method of claim 1, And a pad portion connected to an external driving circuit in the non-display area of the first substrate. The method of claim 8, And a contact pattern in the non-display area of the first substrate, the pad part further including a contact pattern extending from the outer electrode to receive a voltage from the driving circuit to the outer electrode. The method according to any one of claims 2 and 4 and 6, And the protective layer is formed of an organic insulating material. The method according to any one of claims 3 and 4 and 6, And the first and second black matrices are formed of black resin. The method of claim 1, And the first and second polarizers are arranged to have polarization axes perpendicular to each other and are driven in a normally white mode. 13. The method of claim 12, A voltage having a maximum voltage difference is applied between the outer electrode and the common electrode to the outer electrode such that light incident on the liquid crystal layer through the first polarizing plate is perpendicular to the polarizing axis of the first polarizing plate. And preventing the outer electrode from being normally passed through the second polarizing plate, thereby maintaining the normally black state in the forming region. The method of claim 13, The voltage is applied to the outer electrode is a liquid crystal display characterized in that the inversion driving is applied by alternately applying a voltage having a different polarity. The method of claim 1, And the first and second polarizers are arranged to have polarization axes parallel to each other and are driven in a normally black mode. The method of claim 15, The common voltage applied to the common electrode is applied to the outer electrode such that the voltage difference is 0V between the outer electrode and the common electrode, and the light incident on the liquid crystal layer through the first polarizing plate is parallel to the polarization axis of the first polarizing plate. A liquid crystal display device characterized by maintaining a black state at all times by not passing through a second polarizing plate having a polarization axis in one state. The method of claim 1, And at least one yaw portion is formed at a predetermined interval in a region corresponding to the seal pattern of the outer electrode. Forming a gate wiring and a data wiring on the first substrate having an active region displaying an image and a non-display region defined at an edge of the active region to define a pixel region; Forming a switching element at each intersection of the gate line and the data line in each pixel area; The active region and forming a pixel electrode connected to the switching element in each pixel area, and forming an outer electrode Kwak surrounding the active region in the non-display area; Forming a common electrode on an inner surface of the second substrate facing the first substrate; Forming a liquid crystal layer between the first and second substrates; Bonding the first and second substrates by forming a seal pattern outside the active region of the first substrate; Forming first and second polarizing plates on outer surfaces of the first and second substrates, respectively. Method of manufacturing a liquid crystal display device comprising a. The method of claim 18, Forming a first black matrix on the second substrate corresponding to the boundary of each pixel region on the first substrate and a second black matrix surrounding the active region corresponding to the outer electrode; Forming red, green, and blue color filter patterns that are sequentially repeated in the first black matrix corresponding to each pixel area. Method of manufacturing a liquid crystal display device further comprising. The method of claim 18, Forming a first black matrix surrounding each pixel region on the first substrate and a second black matrix surrounding an active region corresponding to the outer electrode; Forming red, green, and blue color filter patterns that are sequentially repeated corresponding to the pixel areas Method of manufacturing a liquid crystal display device further comprising. The method of claim 18, The forming of the outer electrode may further include forming at least one recess portion having a predetermined interval on the outer electrode.

Images