KR20080086267A - Liquid crystal display panel and fabricating method thereof - Google Patents

Abstract

An LCD(Liquid Crystal Display) panel and a method for manufacturing the same are provided to compensate an effective refractive index of a liquid crystal layer in synchronization with the change of a cell gap, thereby uniforming the retardation of the liquid crystal layer and minimizing the variation of transmittance. A thin film transistor substrate(200) includes pixel electrodes and common electrodes in each pixel region. The pixel electrodes and the common electrodes are configured to form a horizontal electric field. A color filter substrate(300) is bound to the thin film transistor substrate with a cell gap therebetween. The color filter substrate includes a common electrode pattern(310) for forming a vertical electric field together with the pixel electrode. A liquid crystal layer(400) is formed between the thin film transistor substrate and the color filter substrate. An effective refractive index of the liquid crystal layer is varied in proportion to an intensity of the vertical electric field according to change of the cell gap. The liquid crystal layer has uniform retardation by compensating the effective refractive index of the liquid crystal layer in inverse proportion to the change of the cell gap.

Description

Liquid Crystal Display Panel and Fabrication Method Thereof}

1 is a cross-sectional view of a conventional horizontal field type liquid crystal display device;

FIG. 2 is a diagram illustrating a change in transmittance according to a cell gap change between a conventional horizontal field type liquid crystal display device and a vertical field type liquid crystal display device.

3 is a cross-sectional view of a horizontal field type liquid crystal display panel according to the present invention;

4A and 4B are a plan view and a cross-sectional view of a thin film transistor substrate constituting a horizontal field type liquid crystal display panel according to the present invention.

5 is a view for explaining a compensation relationship between the cell gap and the effective refractive index of the liquid crystal layer when the cell gap change according to the present invention is set larger than the target value.

6 is a view for explaining a compensation relationship between a cell gap and an effective refractive index of a liquid crystal layer when the cell gap change is set smaller than a target value according to the present invention;

7A and 7B are cross-sectional views of a color filter substrate constituting a horizontal field type liquid crystal display panel according to the present invention;

8A to 8E are manufacturing process diagrams of a thin film transistor substrate constituting a horizontal field type liquid crystal display panel according to the present invention.

9A to 9F are manufacturing process diagrams of a color filter substrate constituting a horizontal field type liquid crystal display panel according to the present invention;

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

100 liquid crystal display panel 200 thin film transistor substrate

202: lower substrate 204: gate line

206: gate electrode 208: common line

210: common electrode 212: gate insulating film

214: data line 216: source electrode

218: drain electrode 220: pixel region

TR: thin film transistor 221: semiconductor pattern

221a: active layer 221b: ohmic contact layer

222: protective film 224: contact hole

226 pixel electrode 228 lower alignment layer

300: color filter substrate 302: upper substrate

304: black matrix 306: color filter

308: over coating layer 310: common electrode pattern

312: upper alignment layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel and a method of manufacturing the same. In particular, by compensating the effective refractive index of the liquid crystal layer due to the increase and decrease of the cell gap through a vertical electric field, the phase retardation value of the liquid crystal layer can be made uniform and the transmittance deviation can be minimized. A horizontal electric field type liquid crystal display panel and its manufacturing method.

Liquid crystal display (LCD) is a device that displays an image by controlling the light transmittance of the liquid crystal by using an electric field, and is implemented as an active matrix type in which switching elements are formed for each cell, so that a computer monitor, office work, etc. It is applied to display apparatuses, such as a device and a cellular phone.

Such liquid crystal displays are roughly classified into a vertical electric field type using a vertical electric field and a horizontal electric field type using a horizontal electric field according to the electric field direction for driving the liquid crystal.

In this case, in the vertical field type liquid crystal display, the common electrode formed on the upper substrate and the pixel electrode formed on the lower substrate face each other to drive the liquid crystal of TN (Twisted Nemastic) mode by a vertical electric field formed therebetween. do. Such a vertical field type liquid crystal display device has a large aperture ratio, but has a narrow viewing angle of about 90 degrees.

In a horizontal electric field type liquid crystal display, an in-plane switch (hereinafter, referred to as IPS) mode liquid crystal is driven by a horizontal electric field between a pixel electrode and a common electrode arranged side by side on a lower substrate. The horizontal field application type liquid crystal display device has a wide viewing angle of about 160 degrees while having a small aperture ratio.

Hereinafter, the configuration and operation of a conventional horizontal field type liquid crystal display device will be described with reference to FIG. 1.

As shown in FIG. 1, the horizontal field type liquid crystal display includes a black matrix 4, a color filter 6, an overcoating layer 8, a spacer 13, and an upper alignment layer formed sequentially on the upper substrate 2. 12, a thin film transistor formed on the lower glass substrate 32, a thin film transistor substrate composed of the common electrode 10, the pixel electrode 56 and the lower alignment layer 52, and a cell formed between the two substrates. It is comprised including the liquid crystal layer dripped between the gaps, and oriented in a horizontal direction.

In the case of the horizontal field type liquid crystal display device configured as described above, as shown in FIG. 2, the transmittance variation of the liquid crystal layer due to the cell gap variation between the two substrates is larger than that of the vertical field type liquid crystal display device. Herein, the cell gap variation of ± 0.1 μm of the vertical field type liquid crystal display generates the same transmittance deviation as the cell gap variation of ± 0.02 μm to 0.04 μm of the horizontal field type liquid crystal display.

Accordingly, in the conventional horizontal field type liquid crystal display device, when the cell gap between two substrates is larger or smaller than the target value, the transmittance deviation is greatly changed as the phase retardation of the liquid crystal layer is changed, thereby causing staining in the panel. There was a problem that the gamma voltage is shifted.

Accordingly, an object of the present invention is to provide a horizontal field type liquid crystal display panel and a method of manufacturing the same, which compensate for the effective refractive index of the liquid crystal layer in association with the change of the cell gap, thereby minimizing the variation in transmittance while uniformizing the phase retardation value of the liquid crystal layer. To provide.

In order to achieve the above object, a horizontal field type liquid crystal display device according to the present invention comprises a thin film transistor substrate having a pixel electrode and a common electrode to form a horizontal electric field in the pixel region; A color filter substrate that is matched with the thin film transistor and the cell gap therebetween and has a common electrode pattern formed together with the pixel electrode to form a vertical electric field; And a liquid crystal layer in which an effective refractive index is changed in association with the magnitude of the vertical electric field that changes according to a cell gap change.

Here, the common electrode pattern according to the present invention is characterized in that the entire surface formed on the color filter substrate.

The common electrode pattern according to the present invention is characterized in that it is patterned on the color filter substrate in a form shifted from the pixel electrode.

When the cell gap between the two substrates according to the present invention is larger than the target value, the effective refractive index of the liquid crystal layer is reduced as the vertical electric field between the pixel electrode and the common electrode is increased.

When the cell gap between the two substrates according to the present invention is smaller than the target value, the effective refractive index of the liquid crystal layer is increased as the vertical electric field between the pixel electrode and the common electrode pattern decreases.

As the effective refractive index of the liquid crystal layer according to the present invention is compensated in the opposite direction to the change of the cell gap in conjunction with the vertical electric field, the liquid crystal layer has a uniform phase retardation.

In order to achieve the above object, a method of manufacturing a horizontal field type liquid crystal display device according to the present invention includes the steps of fabricating a thin film transistor substrate having a pixel electrode and a common electrode for forming a horizontal electric field in the pixel region; Manufacturing a color filter substrate that is matched with a thin film transistor and a cell gap therebetween and has a common electrode pattern formed together with a pixel electrode to form a vertical electric field; And dropping a liquid crystal layer having an effective refractive index variable in association with the magnitude of the vertical electric field that changes according to the cell gap change.

Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 3, the horizontal field type liquid crystal display device 100 according to the present invention includes a thin film transistor substrate 200 having a plurality of thin film patterns and thin film transistors for forming a horizontal electric field, and forming a vertical electric field. The liquid crystal layer 400 is disposed between a color filter substrate 200 having a plurality of thin film patterns and color filters formed thereon and a cell gap formed between the two substrates and aligned in a predetermined direction.

The thin film transistor substrate 200 forms a horizontal electric field for driving the liquid crystal layer 400 dropped between the cell gaps in a predetermined direction. As shown in FIGS. 4A and 4B, the thin film transistor substrate 200 is disposed on the lower substrate 202. The gate line 204 formed at the same time, the common line 208 formed at the same time as the gate line 204 and connected to the common electrode 210, and intersecting with the gate line 204 with the gate insulating film 212 interposed therebetween. A data line 214 defining a pixel region, a thin film transistor TR formed at each intersection of the gate line 204 and the data line 214, a protective film 222 covering the thin film transistor TR, and a protective film. The pixel electrode 226 and the liquid crystal layer 400, which are connected to the thin film transistor TR through the contact hole 224 penetrating 222 and form a horizontal electric field in the pixel region together with the common electrode 210, are disposed in a predetermined direction. The lower alignment layer 228 is oriented.

The gate line 204 transfers a gate signal supplied from a gate driver (not shown) connected to the gate pad to the gate electrode 206 constituting the thin film transistor TR.

The common line 208 is formed in parallel with the gate line 204 with the pixel region interposed therebetween, and supplies a reference voltage for driving the liquid crystal to the common electrode 210.

The data line 214 includes a source electrode 216 and a drain constituting the thin film transistor TR by interlocking a data signal supplied from a data driver (not shown) connected to the data pad with ON / OFF of the gate electrode 206. Transfer to electrode 218.

In this case, the data line 214 crosses the gate line 204 with the gate insulating layer 212 interposed therebetween to define the pixel area.

The thin film transistor (TR) charges the pixel electrode of the data line 214 to the pixel electrode 226 in response to the gate signal of the gate line 204, and the gate electrode 206 connected to the gate line 204. And a source electrode 216 connected to the data line 214 and a drain electrode 218 opposed to the source electrode 216 with the channel interposed therebetween and connected to the pixel electrode 226 through the contact hole 224. ).

In this case, the thin film transistor TR is formed to correspond to the gate electrode 206 with the gate insulating layer 212 therebetween to form a channel, and is formed on the active layer 221a and the source electrode 216. And a semiconductor pattern 221 including an ohmic contact layer 221b for performing ohmic contact with the drain electrode 218.

The pixel electrode 226 is connected to the drain electrode 218 of the thin film transistor TR through a contact hole 224 penetrating through the passivation layer 222 and is crossed with the common electrode 210 connected to the common line 208. Is formed in the pixel region.

Here, the pixel electrode 226 is a common electrode 210 formed on the lower substrate 202 when the data voltage charged to the storage capacitor (not shown) is supplied through the drain electrode 218 of the thin film transistor TR. And a horizontal electric field in which the liquid crystals dropped between the cell gaps are aligned in a predetermined direction.

The pixel electrode 226 cooperates with the common electrode pattern 310 formed on the color filter substrate 300 to form a vertical electric field in the pixel region, and thereby uniformly phase the liquid crystal layer 400 dropped between the cell gaps. By forming the delay value serves to reduce the deviation of transmittance having the following relationship.

(Where T represents the transmittance of the liquid crystal layer, Δneff represents the effective refractive index, and d represents the cell gap in which the liquid crystal layer is dropped)

That is, when the data signal is supplied to the pixel electrode 226 while the cell gap d1 between the two substrates is set larger than the target value, as shown in FIG. 5, the pixel electrode 226 is the color filter substrate 300. A vertical electric field is formed to align the liquid crystal layer 400 dropped in the cell gap d in the vertical direction in conjunction with the common electrode pattern 310 formed at

As described above, when a large vertical electric field VE is formed between the pixel electrode 226 and the common electrode pattern 310 in association with the horizontal electric field HE, the liquid crystal layer 400 dropped between the cell gaps d. As the vertical alignment component of the?) Increases, the effective refractive index? Neff of the liquid crystal layer 400 is compensated in the decreasing direction.

Accordingly, the transmittance of the pixel region is compensated in a direction in which the cell gap d1 is increased while the effective refractive index Δneff of the liquid crystal layer 400 is decreased, and a uniform phase retardation value is applied to the liquid crystal layer 400. ) Is set so that the transmittance does not change, so that the phenomenon of shifting of the stain and gamma voltage generated in the panel does not occur.

However, when the data signal is supplied to the pixel electrode 226 while the cell gap d2 between the two substrates is set smaller than the target value, as illustrated in FIG. 6, the pixel electrode is formed on the color filter substrate 300. An electric field for aligning the liquid crystal layer 400 dropped in the cell gap d2 in the vertical direction is formed in cooperation with the common electrode pattern.

As described above, when a small vertical electric field is formed between the pixel electrode 226 and the common electrode pattern 310 in association with the horizontal electric field, the vertical alignment component of the liquid crystal layer 400 dropped between the cell gap d2 As it decreases, the effective refractive index Δneff of the liquid crystal layer 400 is compensated in the increasing direction.

Accordingly, the transmittance of the pixel region is compensated in a direction in which the cell gap d2 is reduced while the effective refractive index Δneff of the liquid crystal layer 400 is increased, whereby a uniform phase delay value is obtained in the liquid crystal layer 400. At the same time as (Retardation) is set, the transmittance does not fluctuate, so that the phenomenon of shifting of the stain and gamma voltage generated in the panel does not occur.

The color filter substrate 300 forms various colors using light incident through the liquid crystal layer 400. As shown in FIG. 7A, the color filter substrate 300 includes a black matrix 304 formed on the upper substrate 302, and A color filter 306 formed in the pixel region partitioned by the black matrix 304, an overcoating layer 308 to planarize the upper substrate 302 by removing a step formed by the color filter 306, and an overcoating layer A common electrode pattern 310 and an overcoating layer 308 on which the common electrode pattern 310 is formed are formed on the entire surface of the substrate 308 to form a vertical electric field for driving the liquid crystal layer 400 in conjunction with the pixel electrode 226. And an upper alignment layer 312 formed to cover the liquid crystal layer and aligning the liquid crystal layer 400 in a predetermined direction.

In this case, in order to effectively form a vertical electric field in which the color filter substrate 300 aligns the liquid crystal layer in a predetermined direction, as shown in FIG. 7B, the common electrode pattern 310 may include the thin film transistor TR in the overcoat layer 308. The pixel electrode 226 may be formed in a predetermined deviation rather than a symmetrical shape, specifically, symmetrical with the common electrode 210.

The black matrix 304 is formed in a matrix form on the upper substrate 302 to partition a plurality of cell regions in which the color filters 306 are to be formed and to prevent optical interference between adjacent cell regions. The thin film transistor substrate 200 Is overlapped with the gate line 204, the data line 214, and the thin film transistor TR, which are regions excluding the pixel electrode 226.

In this case, the black matrix 304 is deposited on the upper substrate 302 with an opaque metal such as chromium (Cr or CrOx) to have a thickness of about 1500 to 2000 1500 and a line width of 5 to 25 μm. It is formed by patterning it through a photolithography process and an etching process.

In addition, the black matrix 304 may be formed by forming an insulating resin on the upper substrate 302 so as to have a thickness of 1.0 to 1.5 μm and a line width of 5 to 25 μm, and then pattern it through a photolithography process and an etching process. It may be.

The color filter 306 is formed in a plurality of cell regions partitioned by the black matrix 304. In this case, the color filter 306 is sequentially sprayed on the upper substrate 302 by a photo-pigmented color resin having a red, green and blue color by a pigment spray method, and then patterned through a photolithography process and an etching process using a mask, A red color filter 306R for implementing red, a green color filter 306G for implementing green, and a blue color filter 306B for implementing blue.

In this case, the method of implementing the color filter 306 is not limited to the pigment spraying method using the photosensitive color resin, and in addition to the pigment spraying method, various methods such as dyeing, electrodeposition and printing, It is preferred that it be interpreted that it can be formed.

The overcoating layer 308 removes the step formed on the upper substrate 302 by the color filter 306, so that the upper alignment layer 312 formed by the subsequent process can be formed in a flat shape.

The common electrode pattern 310 is formed on the overcoat layer 308, and the vertical electric field for driving the liquid crystal layer 400 dropped in the cell gap in a predetermined direction together with the pixel electrode 226 formed on the thin film transistor substrate 200. To form.

Here, the common electrode pattern 310 is formed on the entire surface of the overcoating layer 308 or in a form that is alternated with the pixel electrode 226 in order to more effectively increase or decrease the effective refractive index of the liquid crystal layer 400 according to the cell gap change. .

In the common electrode pattern 310 configured as described above, when the data signal is supplied to the pixel electrode 226 while the cell gap between the two substrates is set larger than the target value, the pixel electrode 226 as shown in FIG. 5. ) And a large vertical electric field for orienting the liquid crystal layer dropped in the cell gap in the vertical direction.

In this case, when a large vertical electric field is formed between the pixel electrode 226 and the common electrode pattern 310 in association with the horizontal electric field, the vertical alignment component of the liquid crystal layer 400 dropped between the cell gaps d increases. Accordingly, the effective refractive index Δneff of the liquid crystal layer 400 is compensated in the decreasing direction.

When the data signal is supplied to the pixel electrode 226 while the cell gap between the two substrates is set smaller than the target value, the common electrode pattern 310 interlocks with the pixel electrode 226 as shown in FIG. 6. A vertical electric field is formed to orient the liquid crystal layer 400 dropped in the gap in the vertical direction.

In this case, when a small vertical electric field is formed between the pixel electrode 226 and the common electrode pattern 310 in association with the horizontal electric field, the vertical alignment component of the liquid crystal layer 400 dropped between the cell gaps d is reduced. Accordingly, the effective refractive index Δneff of the liquid crystal layer 400 is compensated in the increasing direction.

As described above, the common electrode pattern 310, together with the pixel electrode 226, forms a vertical electric field that compensates the effective refractive index Δneff of the liquid crystal layer 400 in the opposite direction in response to the increase or decrease of the cell gap d. To form a uniform phase retardation in the liquid crystal layer 400, and thus, a phenomenon in which stains and gamma voltages generated in the panel are not generated as the transmittance of the liquid crystal layer 400 is not changed. .

The upper alignment layer 312 covers the overcoat layer 308 on which the common electrode pattern 310 is formed and serves to orient the liquid crystal layer 400 dropped in the cell gap in a predetermined direction. In this case, the upper alignment layer 312 is formed through a rubbing process using an organic alignment layer such as polyimide, and an alignment groove (not shown) for aligning the liquid crystal in a predetermined direction is formed.

Hereinafter, a method of manufacturing a horizontal field type liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

A thin film transistor substrate 200 having a pixel electrode and a common electrode forming a horizontal electric field according to the present invention is manufactured.

As shown in FIG. 8A, a gate line 204, a gate electrode 206, a common line 208, and a common electrode 210 are included on a lower substrate 202 through a first mask process according to the present invention. A first conductive pattern is formed.

In detail, the gate metal layer is formed on the substrate 202 through a deposition method such as sputtering. Here, the gate metal layer is made of aluminum (Al) -based metal, copper (Cu), chromium (Cr), molybdenum, or the like.

After the photoresist is entirely formed on the gate metal layer, a photoresist pattern is formed through the photolithography process using the first mask to expose the remaining regions except for the region where the first conductive pattern is to be formed.

At this time, by etching the region exposed by the photoresist pattern in the gate metal layer, the remaining photoresist pattern is ashed to the gate line 204 and the gate line 204 on the lower substrate 202 according to the present invention. A first conductive pattern including a gate electrode 206 connected to each other, a common line 208 parallel to the gate line 204 with the pixel region interposed therebetween, and a common electrode 210 connected thereto is formed.

As shown in FIG. 8B, the semiconductor pattern 221, the data line 214, and the source electrode 216 perform channel and ohmic contact on the gate insulating layer 212 through the second mask process according to the present invention. And a second conductive pattern including the drain electrode 218.

In more detail, the gate insulating film 212 is coated on the lower substrate 202 on which the first conductive pattern is formed.

Thereafter, the first semiconductor layer, the second semiconductor layer, and the data metal layer are sequentially formed on the gate insulating layer 212 through a deposition method such as PECVD or sputtering.

Herein, amorphous silicon without doping impurities is used as the first semiconductor layer, and amorphous silicon doped with N type or P type impurities is used as the second semiconductor layer, and the data metal layer is molybdenum (Mo) or copper (Cu). ) And the like.

After the photoresist is applied onto the data metal layer, a photolithography process using a second mask is performed to form a photoresist pattern having a predetermined step in the channel region of the data metal layer. Here, a diffraction exposure mask or a transflective mask is used as a 2nd mask.

In this case, the data metal layer exposed by the photoresist pattern is removed by wet etching, and then sequentially dried through etching the first and second semiconductor layers exposed as the data metal layer is removed. To remove it.

As described above, the data metal layer and the first and second semiconductor layers are sequentially removed, and then the photoresist pattern formed in the diffraction exposure region is removed through an ashing process using an oxygen (O ₂ ) plasma to form the channel region. Expose the data metal layer. At this time, the height of the photoresist pattern formed in the blocking region is lowered by an ashing process using an oxygen (O ₂ ) plasma.

Thereafter, the data metal layer exposed to the channel region is removed through wet etching, and then the second semiconductor layer is removed through dry etching, thereby exposing the first semiconductor layer and separating the data metal layer into a source electrode and a drain electrode, respectively.

Here, the first semiconductor layer present on the channel forms the active layer 221a, and the second semiconductor layer formed on the first semiconductor layer includes the data line 214, the source electrode 216, and the drain electrode 218. An ohmic contact layer 221b for ohmic contact with the electrode is formed.

Subsequently, the semiconductor pattern 221 including the active layer 221a and the ohmic contact layer 221b for performing channel and ohmic contact according to the present invention is removed by removing the photoresist pattern 250 remaining on the data metal layer through a strip process. ) And a data line 214 formed to intersect the gate line 204 to define a pixel region, a source electrode 216 connected to the data line 214, and a source electrode 216 facing each other. A second conductive pattern including the drain electrode 218 is formed.

As illustrated in FIG. 8C, a contact hole for covering the second conductive pattern formed on the lower substrate 202 and exposing the drain electrode 218 of the thin film transistor TR through a third mask process according to the present invention ( A protective film 222 having a 224 is formed.

In more detail, the passivation layer 222 is entirely formed on the gate insulating layer 212 on which the semiconductor pattern and the second conductive pattern are formed.

As the material of the passivation layer 222, an inorganic insulating material such as the gate insulating layer 125, an acryl-based organic compound having a low dielectric constant, or an organic insulating material such as BCB or PFCB is used.

Thereafter, the photoresist PR is applied on the passivation layer 222 and then a photolithography process using a third mask is performed, thereby exposing a region of the passivation layer 222 in which the contact hole 224 is to be formed. Form a pattern.

At this time, the contact hole 224 exposing the drain electrode 218 of the thin film transistor TR according to the present invention is removed by removing the remaining photoresist pattern after nicking the passivation layer 222 exposed by the photoresist pattern. The protective film 222 which has is formed.

As shown in FIG. 8D, the pixel electrode 226 connected to the drain electrode 218 through the contact hole 224 is formed on the passivation layer 222 through the fourth mask process according to the present invention.

In more detail, the transparent conductive layer is entirely formed on the passivation layer 222 through a deposition method such as sputtering.

After the photoresist is applied onto the transparent conductive layer, a photolithography process using a fourth mask is performed to form a photoresist pattern exposing the remaining regions of the transparent conductive layer except for the region where the pixel electrode 226 is to be formed.

In this case, the transparent conductive layer exposed by the photoresist pattern is etched and the remaining photoresist pattern is ashed, thereby being connected to the thin film transistor TR on the protective layer 222 through the contact hole 224. The pixel electrode 226 forming a horizontal electric field in the pixel area is formed in cooperation with the common electrode 210.

The pixel electrode 226 configured as described above is dropped between the cell gap together with the common electrode 210 when the data voltage charged to the storage capacitor is supplied through the drain electrode 218 of the thin film transistor TR. A horizontal electric field is formed to orient the liquid crystal in a predetermined direction.

In addition, the pixel electrode 226 forms a vertical electric field in the pixel region in conjunction with the common electrode pattern 310 formed on the color filter substrate 300, thereby compensating the effective refractive index of the liquid crystal layer in response to the cell gap variation. Thereby reducing the transmittance variation of the liquid crystal layer.

As illustrated in FIG. 8E, the lower alignment layer 228 having an alignment groove covering the passivation layer 222 on which the pixel electrode 226 according to the present invention is formed and orientating the liquid crystal layer 400 dropped in the cell gap in a predetermined direction is formed. ) To finally complete the thin film transistor substrate 200.

A color filter substrate 300 having a common electrode pattern and a color filter forming a vertical electric field according to the present invention is manufactured.

As shown in FIG. 9A, a black matrix 304 is formed on the upper substrate 302 according to the present invention to partition the cell region.

In more detail, an opaque metal such as chromium (Cr or CrOx) is deposited on the upper substrate 302 to have a thickness of about 1500 to 2000 microns and a line width of 5 to 25 μm.

Subsequently, by performing a photolithography process using a mask on the opaque metal, a plurality of cell regions formed in a matrix form on the upper substrate 302 and on which the color filters 306 are to be formed are partitioned and light between adjacent cell regions is simultaneously formed. A black matrix 302 is formed to prevent interference.

As shown in FIG. 9B, the color filter 306 is formed in the cell region partitioned by the black matrix 304 according to the present invention.

In more detail, on the upper substrate 302 on which the black matrix 304 is formed, photosensitive color resins having red, green, and blue colors are sequentially formed through a pigment spraying method.

Thereafter, a photolithography process using a mask is sequentially performed on the photosensitive color filter, so that the red color filter 306R, the green color filter 306G, and the blue color filter 306B in the cell region partitioned by the black matrix 304. A color filter consisting of) is formed.

As shown in FIG. 9C, an overcoat layer 308 is formed on the upper substrate 302 according to the present invention to remove the step formed by the color filter 306.

In more detail, the thermosetting resin such as polydimethyl siloxane is formed on the upper substrate 302 on which the color filter 306 is formed.

Thereafter, a photolithography process using a mask is performed on the thermosetting resin to form an overcoating layer 308 that removes a step formed on the upper substrate 302 by the color filter 306. In this case, when forming the overcoating layer 308, a spacer may be formed at the same time to fill the liquid crystal.

As shown in FIG. 9D, a common electrode pattern 310 is formed on the overcoat 308 according to the present invention to generate a vertical electric field together with the pixel electrode 226.

In more detail, the common electrode material is entirely formed on the overcoat layer 308 through a deposition process such as PECVD.

After the entire photoresist is formed on the common electrode material, a photoresist pattern exposing the remaining regions except for the region where the common electrode pattern 310 is to be formed is formed by a photolithography process using a mask according to the present invention.

By nicking the common electrode material exposed by the photoresist pattern, the liquid crystal layer dropped in the cell gap in conjunction with the pixel electrode 226 formed on the thin film transistor substrate 200 on the overcoat layer 308 of the present invention is disposed in a predetermined direction. A common electrode pattern 310 for generating a vertical electric field to be driven is formed.

Here, the common electrode pattern 310 is formed on the entire surface of the overcoating layer 308 or in a form that is alternated with the pixel electrode 226 to more effectively increase or decrease the effective refractive index of the liquid crystal layer according to the cell gap change.

In the common electrode pattern 310 configured as described above, when the data signal is supplied to the pixel electrode 226 while the cell gap between the two substrates is set larger than the target value, the pixel electrode 226 as shown in FIG. 5. ) And a large vertical electric field for orienting the liquid crystal layer dropped in the cell gap in the vertical direction.

In this case, when a large vertical electric field is formed between the pixel electrode 226 and the common electrode pattern 310 in association with the horizontal electric field, the vertical alignment component of the liquid crystal layer 400 dropped between the cell gaps d1 is increased. Accordingly, the effective refractive index Δneff of the liquid crystal layer 400 is compensated in the decreasing direction.

When the data signal is supplied to the pixel electrode 226 while the cell gap between the two substrates is set smaller than the target value, the common electrode pattern 310 interlocks with the pixel electrode 226 as shown in FIG. 6. A small vertical electric field is formed to orient the liquid crystal layer dropped in the cell gap in the vertical direction.

In this case, when a small vertical electric field is formed between the pixel electrode 226 and the common electrode pattern 310 in association with the horizontal electric field, the vertical alignment component of the liquid crystal layer 400 dropped between the cell gaps d2 is reduced. Accordingly, the effective refractive index Δneff of the liquid crystal layer 400 is compensated in the increasing direction.

As described above, the common electrode pattern 310 together with the pixel electrode 226 forms a vertical electric field that compensates the effective refractive index Δneff of the liquid crystal layer 400 in the opposite direction in response to the increase or decrease of the cell gap. A uniform phase retardation is set in the layer 400, and thus, a phenomenon in which stains and gamma voltages generated in the panel are prevented from occurring is generated as the transmittance of the liquid crystal layer 400 is not changed.

In this case, as shown in FIG. 9E, the common electrode pattern 310 and the pixel electrode 226 are formed on the overcoat layer 308 to increase or decrease the effective refractive index of the liquid crystal layer 400 according to the cell gap change. It may be formed in a staggered form.

As shown in FIG. 9F, the upper alignment layer 312 covers the overcoat layer 308 on which the common electrode pattern 310 according to the present invention is formed, and the liquid crystal layer 400 dropped in the cell gap is aligned in a predetermined direction. And finally the color filter substrate 300 is completed.

As shown in FIG. 3, the thin film transistor substrate 200 and the color filter substrate 300 completed through the above process are bonded to each other with the liquid crystal layer 400 dropped therebetween. Uniform phase delay in the liquid crystal layer 400 by compensating the effective refractive index Δneff of the liquid crystal layer 400 according to the cell gap variation through a vertical electric field formed between the electrode 226 and the common electrode pattern 310. Finally, the horizontal field type liquid crystal display panel 100 capable of setting a retardation is completed.

As described above, the present invention forms a common electrode pattern on the color filter substrate to generate a vertical electric field in conjunction with the pixel electrode, thereby compensating the effective refractive index? Neff of the liquid crystal layer due to the increase or decrease of the cell gap d. By forming a uniform phase retardation (minimum) while minimizing transmittance variation, it is possible to prevent the phenomenon of shift of the stain and gamma voltage in the panel.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (12)

A thin film transistor substrate having a pixel electrode and a common electrode forming a horizontal electric field in the pixel region; A color filter substrate matched with the thin film transistor and a cell gap therebetween and having a common electrode pattern formed together with the pixel electrode to form a vertical electric field; And And a liquid crystal layer in which an effective refractive index is changed in proportion to the intensity of the vertical electric field according to the cell gap change. The method of claim 1, And the common electrode pattern is entirely formed on the color filter substrate. The method of claim 1, And the common electrode pattern is patterned on the color filter substrate in a form that is displaced from the pixel electrode. The method of claim 1, If the cell gap is larger than the target value, the effective refractive index of the liquid crystal layer is reduced as the vertical electric field between the pixel electrode and the common electrode increases. The method of claim 1, If the cell gap is smaller than the target value, the effective refractive index of the liquid crystal layer is increased as the vertical electric field between the pixel electrode and the common electrode pattern is reduced. The method according to claim 4 or 5, And the liquid crystal layer has a uniform phase retardation as the effective refractive index of the liquid crystal layer is compensated in the opposite direction to the change of the cell gap in conjunction with the vertical electric field. Manufacturing a thin film transistor substrate on which a pixel electrode and a common electrode are formed to form a horizontal electric field in the pixel region; Manufacturing a color filter substrate that is matched with the thin film transistor and a cell gap therebetween and has a common electrode pattern formed with a pixel electrode to form a vertical electric field; And And dropping a liquid crystal layer having an effective refractive index variable in association with the size of the vertical electric field that changes according to the cell gap change. The method of claim 7, wherein And the common electrode pattern is entirely formed on the color filter substrate. The method of claim 7, wherein And the common electrode pattern is patterned on the color filter substrate in a form that is displaced from the pixel electrode. The method of claim 7, wherein And when the cell gap is larger than a target value, the effective refractive index of the liquid crystal layer decreases as the vertical electric field between the pixel electrode and the common electrode increases. The method of claim 7, wherein And when the cell gap is smaller than a target value, the effective refractive index of the liquid crystal layer is increased as the vertical electric field between the pixel electrode and the common electrode pattern decreases. The method of claim 10 or 11, As the effective refractive index of the liquid crystal layer is compensated in the opposite direction to the change of the cell gap in conjunction with the vertical electric field, the liquid crystal layer has a uniform phase retardation value (retardation) of the horizontal field type liquid crystal display panel Manufacturing method.

Images