KR20110075187A - In-plane switching mode transflective type liquid crystal display device - Google Patents

Abstract

PURPOSE: An in-plane switching mode reflection and transmission type LCD device is provided to improve black brightness by restricting a twisting error. CONSTITUTION: The in-plane switching mode reflection and transmission type LCD device includes a first alignment layer, and a second alignment layer(189). The first alignment layer processed to a first direction which is included inside a surface of the first substrate. The second alignment layer processed to the first direction with the same alignment layer and is included inside a second substrate. A liquid crystal layer has a spiral structure in which a chiral nematic liquid crystal molecule is twisted numerically in a power off state in a common electrode and a pixel electrode. A spiral axis is parallel to an optical axis.

Description

In-plane switching mode transflective type liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, a transverse electric field mode reflection-transmitting liquid crystal in which the alignment direction is matched in the reflection area and the transmission area to suppress the formation of the disclination area, and at the same time improve the black and white luminance characteristics. It relates to a display device.

In general, a liquid crystal display device is a display device using characteristics of liquid crystal molecules that differ in arrangement depending on voltage application. The liquid crystal display device can be driven at a lower power than a cathode ray tube, and is advantageous in miniaturization and thinning. BACKGROUND ART There is a spotlight as a flat panel display device such as a television, and since it is easy to carry due to its lightweight and thin characteristics, it is used as a display element of a notebook or a personal portable terminal.

In the liquid crystal display, two substrates on which electrodes are formed are disposed so that the two electrodes face each other, and a liquid crystal is generated by an electric field generated by a voltage difference applied to the two electrodes through a liquid crystal between the two substrates. By controlling the movement of molecules, it is a device that expresses an image by controlling the transmittance of light that varies accordingly.

On the other hand, the liquid crystal display device is generally a passive element that does not emit light by itself, so a separate light source is required. Therefore, in addition to the liquid crystal panel (panel) consisting of the two substrates and the liquid crystal layer (backlight) for providing a light (light) to the rear side (light) and the light emitted from the backlight is incident on the liquid crystal panel, according to the arrangement of the liquid crystal The image is displayed by adjusting the amount.

Such a liquid crystal display device is called a transmission type liquid crystal display device. Since the liquid crystal display device uses an artificial light source such as a backlight, a bright image can be realized even in a dark external environment, but a portable device is required because power must be supplied to the backlight. When used as a display device of a relatively large power consumption (power consumption) is a disadvantage.

Accordingly, a reflection type liquid crystal display device using an external light source without using a backlight has been proposed to compensate for such a disadvantage.

Since the reflective liquid crystal display device operates by using external natural light or artificial light, it significantly reduces the amount of power consumed by the backlight, so the power consumption is relatively small compared to the transmissive type, and thus it can be used in a portable state for a long time. It is mainly used as a display element of a portable device such as an assistant.

However, such a reflective liquid crystal display device has an advantage of low power consumption because it does not have a separate light source, but there is a disadvantage that it can not be used in the place where the external light is weak or no.

Therefore, recently, a transflective liquid crystal display device having only the advantages of a reflective liquid crystal display device and a transmissive liquid crystal display device has been proposed. In the case of such a transflective liquid crystal display device, mainly an electrically controlled birefringence (ECB) mode or It is mainly implemented in VA (vertical alignment) mode, the ECB mode has a disadvantage of low viewing angle, and VA mode also requires a large number of viewing angle compensation film to further improve the viewing angle, causing a problem of increased manufacturing cost. Doing.

On the other hand, in the case of the liquid crystal display device, due to its lightweight and thin structure, it has recently escaped from a personal display device such as a portable notebook and is widely used as a mass media such as a TV, so that a large number of users can watch from various angles instead of only an individual. Therefore, viewing angle is becoming an important issue.

Therefore, in order to overcome the disadvantages of the low viewing angles of the above-described VA mode and ECB mode liquid crystal display devices, both the common electrode and the pixel electrode are formed on the same substrate and are driven by the transverse electric field, thereby improving the range of the viewing angle. Display devices have been proposed.

1 is a simplified cross-sectional view of a reflection area and a transmission area of a conventional transverse electric field mode reflection-transmissive liquid crystal display device. In this case, the pixel region is defined as a reflection region where a reflection plate is formed so that light does not pass from below and a transmission region in which the reflection plate is not formed.

As shown in the drawing, a gate line (not shown) and a data line (not shown) intersect with each other to define the pixel region P, and are parallel to the gate line (not shown). A common wiring (not shown) is formed to extend and penetrate the pixel region P. A thin film transistor, which is a switching element, is formed in each pixel region P. Referring to FIG.

In addition, a reflective plate 50 is formed of a metal material having good reflectance in the reflective region RA, and a pixel electrode 70 is formed in the pixel region P on the reflective plate 50.

In addition, a common electrode 80 is connected to the common wiring (not shown) through the insulating layer 72 and has a plurality of bar-shaped openings op1 and op2 over the pixel electrode 70. It is being formed. In this case, the plurality of openings op1 and op2 are divided into a plurality of first openings op1 and a plurality of second openings op2 and are provided in the transmission area TA and the reflection area RA, respectively. The first and second openings op1 and op2 are characterized by varying the directions of their major axes.

An overcoat layer 88 is formed on the front surface of the color filter layer 86 and the front surface of the color filter layer 86 so as to face the array substrate 2 having such a configuration and correspond to a black matrix (not shown) and each pixel region P at the boundary of the pixel region P. The provided color filter substrate 83 is provided, and the liquid crystal layer 90 is interposed between the array substrate 2 and the color filter substrate 83.

On the other hand, although the conventional transverse electric field mode reflection-transmissive liquid crystal display device 1 having the above-described configuration is not shown in the figure, the thickness of the liquid crystal layer 90 in the transmission area TA (hereinafter referred to as first cell gap d1). Is doubled to the cell gap d2 in the reflection area RA. This is to match the retardation that the light in the liquid crystal layer 90 feels. In the case of the transmission area TA, the user may receive light from the backlight unit (not shown) located under the array substrate 2. As it is seen, while passing through the liquid crystal layer 90 once, in the reflection area RA, external light is incident on the display area of the liquid crystal display device 1 and is reflected by the reflection plate 50 and comes out again. Since the user sees light, the light passes through the liquid crystal layer 90 twice.

Therefore, in this process, the light coming out of the reflection area RA and the light coming out of the transmission area TA have different retardation values, so that the reflection area RA forms a cell of λ / 4 to match the transmission area TA. Is configured to vary the thickness of the liquid crystal layer 90 to form a cell of λ / 2.

In the conventional transverse electric field mode reflection-transmissive liquid crystal display device 1 having such a configuration, the polarization axis of the second polarizing plate 95 and the director in the long axis direction of the liquid crystal molecules form 45 degrees in the λ / 4 cell. When black is realized, the transmission area TA has a double thickness of the liquid crystal layer compared to the reflection area RA, that is, λ / 2 cells, so when the polarization axes of the director and the second polarizing plate are arranged side by side, the black This is implemented.

However, the transverse electric field mode reflection-transmissive liquid crystal display device having the above-described configuration does not have an initial arrangement of the liquid crystal director for black and white expression due to the difference in the direction of the first and second openings in the reflection area and the transmission area in the array substrate. In order to change the initial arrangement of the liquid crystal director, the direction of orientation in the reflection area and the transmission area is different.

In order to change the orientation direction in the reflective and transmissive regions, the divisional alignment must be performed using a UV alignment apparatus, etc., so that the alignment time is longer than the orientation so as to have the same orientation direction, and productivity per unit time is reduced. An error occurs in the UV irradiation amount and irradiation angle for each pixel region during the segmentation alignment process, and a slight error in the orientation angle occurs for each pixel region, causing a misalignment of the alignment direction with the polarization axis of the polarizer to reduce the overall black brightness. It is the situation.

In addition, since the direction between the liquid crystal directors is rapidly changed at the boundary between the reflection area and the transmission area due to the difference in the alignment direction between the reflection area and the transmission area, a problem arises in the occurrence of a decrease in aperture ratio due to a sharp decrease in luminance. It is happening.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and does not require a divided orientation, and enables the orientation by rubbing to have the same orientation in the reflective and transmissive regions, thereby increasing the degree of freedom of the alignment process and the unit. It is an object of the present invention to provide a reflection-transmissive liquid crystal display device which can improve productivity per hour, and can improve black luminance by suppressing a polarization axis and a misalignment error generated during divisional alignment.

Furthermore, another object of the present invention is to provide a transverse electric field mode reflective transmissive liquid crystal display device capable of suppressing the declining occurring at the boundary between the reflective region and the transmissive region to improve the aperture ratio and the luminance.

A transverse electric field mode reflection-transmissive liquid crystal display device according to the present invention includes a first substrate having a common electrode and a pixel electrode formed in a pixel region having a reflection region and a transmission region, a second substrate facing the color filter layer, and two substrates thereof. In the transverse electric field mode reflection-transmitting liquid crystal display device having a liquid crystal layer interposed therebetween, the first substrate is provided with a pixel electrode and a common electrode which are alternately disposed in the reflective region and the transmissive region with each other, A first alignment layer disposed on an inner surface of the first substrate and aligned in a first direction; A second alignment layer disposed on an inner surface of the second substrate and aligned in a first direction in the same direction as the first alignment layer, wherein the liquid crystal layer has a short pitch in a voltage-off state to the common electrode and the pixel electrode; A chiral nematic liquid crystal molecule having a pitch of (pitch) has a spiral structure twisted tens of times, and a spiral axis is parallel to an optical axis, and voltage is applied to the common electrode and the pixel electrode. In this state, the rearrangement of the liquid crystal molecules forming the spiral is generated, so that the optical axis is inclined with respect to the spiral axis, and the USH mode liquid crystal has a characteristic of expressing birefringence.

When the voltage is applied, the optical axis is inclined to have an angle of 20 degrees to 60 degrees with respect to the spiral axis, and the maximum inclination of the optical axis inclined with respect to the spiral axis in the reflection area and the transmission area is different from each other. to be.

A gate wiring and a data wiring formed on the inner surface of the first substrate by crossing the gate insulating film to define the pixel region; A common wiring formed in parallel with the gate wiring; A thin film transistor connected to the gate line and the data line in the pixel area; A first passivation layer covering the data line and the thin film transistor; A reflection plate formed in the reflection area over the first protective layer; A second protective layer formed over the reflecting plate; The pixel electrode in contact with the drain electrode through a drain contact hole exposing the drain electrode of the thin film transistor over the second passivation layer and formed in a plate shape in the pixel region; A third passivation layer formed over the pixel electrode; A plurality of first openings connected to the common protective layer through the common contact hole on the third passivation layer and spaced apart from each other in the transmissive area with a long axis in a second direction, and in the reflective area with a long axis in a third direction The common electrode includes a plurality of spaced apart second openings.

A gate wiring and a data wiring formed on the inner surface of the first substrate by crossing the gate insulating film to define the pixel region; A common wiring formed in parallel with the gate wiring; A thin film transistor connected to the gate line and the data line in the pixel area; A first passivation layer covering the data line and the thin film transistor; A reflection plate formed in the reflection area over the first protective layer; A second protective layer formed over the reflecting plate; Contact with the drain electrode through a drain contact hole exposing the drain electrode of the thin film transistor to the upper portion of the second protective layer, and have a plurality of bars in the second direction and spaced apart from each other in the transmissive region; A plurality of pixel electrodes formed in the reflection areas and spaced apart from each other in a third direction; A third passivation layer formed over the pixel electrode; And a plurality of common electrodes connected to the common protective layer through the common contact hole on the third passivation layer and alternately spaced apart from the plurality of pixel electrodes in the reflective and transmissive regions, respectively.

In addition, the first and second substrates respectively include first and second polarizing plates disposed on outer surfaces thereof and the polarization axes thereof are orthogonal to each other.

In addition, the liquid crystal layer is characterized in that the thickness is different in the reflective region and the transmission region, wherein the thickness of the liquid crystal layer in the transmission region is characterized by twice the thickness of the liquid crystal layer in the reflection region.

In addition, the liquid crystal layer is characterized in that the thickness is the same in the reflective region and the transmission region, the λ / 4 phase difference plate is provided in the reflective region of the first substrate.

In addition, the color filter layer is patterned and removed at a central portion thereof corresponding to the reflective region, so that a transmission hole is formed.

The present invention does not require a divided orientation, and by allowing rubbing to have the same orientation in the reflective and transmissive regions, it is possible to increase the degree of freedom of the alignment process and improve productivity per unit time, There is an effect of improving the black brightness by suppressing the distortion error.

In addition, by matching the orientation directions in the reflection area and the transmission area, it is possible to suppress the discernment occurring at the boundary between the reflection area and the transmission area, thereby improving the aperture ratio and luminance.

In addition, since the liquid crystal layer is driven by a transverse electric field and has a USH mode liquid crystal, the liquid crystal layer is substantially VA driven based on the optical axis, and thus has a fast response speed, and the liquid crystal is twisted based on the optical axis. Since it achieves the advantage that has a wide viewing angle characteristics.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the reflective liquid crystal display device according to the present invention.

The most characteristic feature of the transflective liquid crystal display according to the present invention is that the alignment direction in the reflective region and the transmissive region is matched by including the uniformly standing helix (USH) mode liquid crystal.

First, the driving principle of the USH mode liquid crystal will be described with reference to the drawings.

2A and 2B are schematic views illustrating driving principles of USH mode liquid crystals in the reflection type liquid crystal display according to the present invention. Is a schematic diagram showing the driving principle of the USH mode liquid crystal in the reflective transmissive liquid crystal display device according to the present invention.

As shown, in the voltage-off state, the USH-mode liquid crystal has a helical structure in which a short pitch chiral nematic liquid crystal molecule is twisted several ten times, wherein the axis of the spiral structure, that is, The spiral axis Z is characterized by being parallel to the optical axis OAX.

Meanwhile, in the voltage applied state, the USH mode liquid crystal rearranges the liquid crystal molecules forming the spiral, thereby causing the optical axis OAX to be distorted with respect to the spiral axis Z, and birefringence is expressed.

As a result, almost perfect black is realized without voltage being applied, and the inclination of the optical axis OXA with respect to the spiral axis Z is changed by applying voltage, thereby implementing gray and white. In this case, the optical axis OXA is inclined in proportion to the voltage intensity applied in the voltage application direction.

In addition, the USH mode liquid crystal has a very fast response time because bimesogen liquid crystals are arranged in a structure having polarity.

On the other hand, the USH mode liquid crystal has a spiral structure in which chiral nematic liquid crystal molecules of short pitch are twisted several dozen times, and the axis of the spiral structure, that is, the spiral axis Z, is a direction in which light travels ( parallel to z direction). Moreover, it has the same refractive index with respect to the x and y direction perpendicular | vertical to a z direction. (n _x = n _y ), ie, optical isotropic properties in the front viewing angle.

In addition, the first and second polarizers (not shown) respectively provided on the outermost side of the reflection type liquid crystal display device (not shown) including the USH mode liquid crystal have polarization axes (not shown) perpendicular to each other. Due to the optical isotropy as described above, light leakage does not occur at the front viewing angle.

Therefore, when no voltage is applied, birefringence is not expressed at the frontal viewing angle, and it has an advantage of obtaining excellent black characteristics.

In addition, when no voltage is applied, the USH mode liquid crystals have the same liquid crystal array regardless of the reflection area and the transmission area since the optical axes OAX are arranged in the same direction. Therefore, the disclination phenomenon caused by the initial arrangement state of the different liquid crystals in the reflection region and the transmission region can be suppressed, and therefore, the black luminance and the aperture ratio characteristics are improved.

On the other hand, when the voltage is applied, the optical axis is inclined in the direction of the electric field generated by the voltage application, and thus gray and white are displayed according to the increase and decrease of the angle at which the optical axis OAX is inclined. By passing through the color filter layer (not shown), colors having various gray levels are realized.

FIG. 4 is a plan view of one pixel area of a transverse electric field mode reflection-transmissive liquid crystal display device according to a first embodiment of the present invention, and FIG. 5 is a cross-sectional view of a portion taken along the cutting line V-V of FIG. 4. . For convenience of description, a region in which the thin film transistor Tr, which is a switching element, is formed in the pixel region P is defined as a switching region TrA, and at the same time, a portion where the reflector is formed in the pixel region P is a reflection region RA. ) And the other areas are defined as the transmission area TA.

As shown in the drawing, the gate wiring 103 and the data wiring 125 intersect with each other to define the pixel region P, and extend in parallel with the gate wiring 103. The common wiring 109 penetrating the pixel region P is formed. In this case, a first storage electrode 110 is formed in the reflective region RA by branching from the common wiring 109, and a second storage electrode is branched from the common wiring 109 on the data line 125. 111 is formed.

In addition, each pixel region P is connected to the gate wiring 103 and the data wiring 125 and has a gate electrode 106, a gate insulating film 115, an active layer 120a of pure amorphous silicon, and an impurity amorphous material. The semiconductor layer 120 including the ohmic contact layer 120b of silicon and the thin film transistor Tr including the source and drain electrodes 130 and 133 spaced apart from each other are formed.

In addition, the drain electrode 133 is formed to overlap with the first storage electrode 110 and the gate insulating layer 115 therebetween, and the first storage electrode 110 and the drain electrode overlapping each other ( 133 includes a gate insulating film 115 interposed between the two electrodes 110 and 133 to form a first storage capacitor StgC1. In addition, the second storage electrode 111 and the data line 125 overlapping each other with the gate insulating layer 115 interposed therebetween to form a second storage capacitor StgC2.

In addition, a first protective layer 136 is formed as an inorganic insulating material covering the thin film transistor Tr and the data line 125, and a second protective layer as an organic insulating material on the first protective layer 136. 140 is formed on the front surface. At this time, the second protective layer 140 is characterized in that the concave-convex irregularities are formed on the surface of the reflective region (RA).

In addition, a third passivation layer 142 is formed on the second passivation layer 140 as an inorganic insulating material, and a metal material having good reflectance on the reflecting region RA is formed on the third passivation layer 142. The reflecting plate 150 is formed. At this time, the third protective layer 142 and the reflective plate 150 is characterized in that the surface of the convex concave-convex shape due to the influence of the second protective layer 140 formed on the bottom.

In the first embodiment of the present invention, the first to third protective layers 136, 140, and 142 are shown as an example, but the first and third protective layers 136 and 142 may be omitted. have. Since the first protective layer 136 made of an inorganic insulating material is in contact with the active layer 120a, characteristics of channel contamination and thin film transistor (Tr) that may occur when the organic insulating material is in contact with the active layer 120a The third protective layer 142 may be formed to prevent degradation, and the third protective layer 142 may be formed of the third reflective layer 150 made of a metal material and the third organic material. It is formed between the protective layer 142.

Next, a fourth passivation layer 152 is formed on the reflective plate 150 to correspond to the reflective region RA as an organic insulating material. The fourth passivation layer 152 forms a step difference with the transmission area TA to form the double cell gaps d3 and d4 in the reflection area RA and the transmission area TA.

In addition, a fifth passivation layer 155 is formed on the entire surface of the fourth passivation layer 152 and the third passivation layer 142 as an inorganic insulating material. At this time, the fifth passivation layer 155 and the third passivation layer 142, the second and the first passivation layer (below) outside the end of the fourth passivation layer 152 in the pixel region P. 140 and 136 are patterned to have drain contact holes 158 exposing the drain electrode 133.

 Next, a plate-shaped pixel electrode 160 is formed for each pixel region P from the fifth passivation layer 155 and a transparent conductive material. In this case, the pixel electrode 160 is in contact with the drain electrode 133 of the thin film transistor Tr through the drain contact hole 158.

Meanwhile, the fifth protective layer 155 made of an inorganic insulating material is also formed to improve adhesion between the fourth protective layer 152 made of an organic insulating material and the pixel electrode 160 made of a transparent conductive material. Can be.

In addition, a sixth protective layer 163 is formed on the pixel electrode 160 as an inorganic insulating material, and a transparent conductive material is formed on each of the pixel areas P or on the sixth protective layer 163. The common electrode 170 is formed on the entire display area of the array substrate 102. In the drawing, the common electrode 170 is formed on the entire display area. In this case, although not shown, the common electrode 170 is in contact with the common wire 109 through a common contact hole (not shown).

Meanwhile, the major axis of the common electrode 170 has a first direction, and a plurality of first openings op1 are formed to be spaced apart at regular intervals. In the case of the reflective area RA, the major axis of the common electrode 170 has a plurality of major axes in the second direction. The second openings op2 are formed at regular intervals apart.

In addition, a first alignment layer 172 is provided on the common electrode 170 having the plurality of first and second openings op1 and op2.

The color filter substrate 181 is provided corresponding to the array substrate 102 having the above-described configuration.

On the inner surface of the color filter substrate 181 facing the array substrate 102, a black matrix 183 is formed to correspond to the boundary of each pixel region P, that is, the gate and data lines 103 and 125. And a color filter layer 185 formed of red, green, and blue color filter patterns (R, G, not shown) that cover the black matrix 183 and are sequentially repeated corresponding to each pixel region (P). It is. In this case, the color filter layer 185 is patterned and removed to correspond to the central portion of the reflection area RA in each pixel area P, so that the color filter layer 185 includes a transmission hole TH. The configuration of the transmission hole TH in the reflection area RA may be omitted to improve luminance in the reflection area RA.

An overcoat layer 187 is formed on the entire surface of the color filter substrate 181 and covers the color filter layer 185 having the transmission hole TH. Although not shown in the drawings, the overcoat layer 187 covers the overcoat layer 187. The alignment film 189 is provided.

In addition, first and second polarizing plates 193 and 195 having polarization axes orthogonal to each other are provided on the outer surfaces of each of the array substrate 102 and the color filter substrate 181.

Meanwhile, between the first and second alignment layers 172 and 189, a second thickness d4 corresponds to the transmission area TA, and a second thinner than the first thickness d4 in the reflection area RA. A USH mode liquid crystal layer 190 having a thickness d3 is provided. In this case, the second thickness d3 is 1/2 of the first thickness 4.

In the transverse electric field mode reflection-transmissive liquid crystal display 101 having the above-described configuration, the most characteristic configuration is that the first and second alignment layers 172 and 189 are independent of the reflection area RA and the transmission area TA. All of them are oriented in the same direction. In the drawing, the data line 125, which is the reference direction, is formed along the extension direction of the A degree, and in this case, the A degree is 0 to 360 degrees, characterized in that it can be oriented in any direction.

Thus, even though the first and second alignment layers 172 and 189 are aligned in the same direction irrespective of the reflection area RA and the transmission area TA, the USH mode liquid crystal is characterized in that the liquid crystal layer 190 This USH mode liquid crystal is not a problem because the optical axis is arranged in a direction perpendicular to the surface of the array substrate 101 in the state that no electric field is applied.

In addition, the initial alignment state of the USH-mode liquid crystals in the reflection area RA and the transmission area TA does not coincide to cause disclination at the boundary between the reflection area RA and the transmission area TA. It is characterized by not.

On the other hand, the operations in the reflection area RA and the transmission area TA are different in the directions of the first and second openings op1 and op2 in the reflection area RA and the transmission area TA, and the openings op1 and op2) the width of the optical axis is adjusted in the reflection area RA and the transmission area TA so as to be driven by adjusting the inclination direction and the inclination angle.

In this case, the alignment of the first and second alignment layers 172 and 189 is performed in the same direction so that rubbing is performed. Thus, in the first embodiment of the present invention, the rubbing is performed so that the orientation is performed in the same direction with respect to the entire surfaces of the substrates 102 and 181 without the distinction between the reflection area RA and the transmission area TA. This is because the orientation by rubbing is the simplest and the processing speed is also faster than the UV alignment irradiating the UV beam, thereby shortening the orientation processing time per unit time.

On the other hand, the inclination of the maximum optical axis of the USH mode liquid crystal made in the white driving can be freely selected in the range having an angle of about 20 degrees to 60 degrees with the initially arranged optical axis or spiral axis.

The transverse electric field mode reflection-transmissive liquid crystal display device 101 according to the first embodiment of the present invention having the above-described configuration is driven by a fringe field, which is a kind of transverse electric field, but has a USH mode liquid crystal and is substantially in VA mode. Since it operates, it has a fast response speed, which is a VA mode characteristic, and has a wide viewing angle characteristic at the same time because the liquid crystal forms a twisted array of 0 to 360 degrees based on the optical axis in the USH mode liquid crystal characteristics.

Meanwhile, in the above-described first embodiment of the present invention, the common electrode 170 having a plurality of first and second openings op1 and op2 is formed on the entire display area in the array substrate 102, and the pixel electrode The 160 is formed in each pixel region P in the form of a plate to generate a fringe field by the first and second openings op1 and op2 of the common electrode 170 and the pixel electrode 160. However, as a modification thereof, the pixel electrode and the common electrode may be formed to have a finger shape and alternately arranged so that the common electrode and the pixel electrode adjacent to each other generate a transverse electric field. .

In addition, although not shown in the drawing, as a further modification of the first embodiment, in order to change the cell gap in the reflection area and the transmission area, the fourth protection layer 152 only for the reflection area RA of the array substrate 102 in the case of the embodiment. The double cell gaps d3 and d4 are formed by forming a reference numeral, but instead of the fourth protective layer 152 formed on the array substrate 102, the double cell gaps d3 and d4 are omitted, and the reflective area RA is formed on the inner surface of the color filter substrate 181. By forming the second overcoat (not shown) corresponding to the above, the reflection area RA and the transmission area TA may be formed to have different cell gaps.

6 is a cross-sectional view of one pixel area of a transverse electric field mode reflective transmissive liquid crystal display according to a second embodiment of the present invention. For convenience of description, the same reference numerals are added to 100 to correspond to the same components as the first embodiment.

In the second embodiment of the present invention, the reflective region RA and the transmission region TA are both configured to have a single cell gap d5.

Therefore, the part different from the first embodiment is that the fourth protective layer 252 provided for the step difference between the reflection area RA and the transmission area TA is not only reflected in the reflection area RA but also in the transmission area TA. It is characterized by being formed, and other components have the same structure as 1st Embodiment.

As described above, in the case of the second embodiment of the present invention having a single cell gap d5, only in response to the reflection area RA in order to overcome the phase difference between the reflection area RA and the transmission area TA. The common electrode 270 may be provided with a 1 / λ retardation plate (not shown) on the upper side, or the maximum inclination angle with respect to the initially arranged optical axis of the optical axis of the USH liquid crystal may reflect the reflection area RA and the transmission area TA. In this case, the phase difference between the reflection area RA and the transmission area TA may be overcome by driving differently.

Meanwhile, in the above-described second embodiment of the present invention, the common electrode 270 having a plurality of first and second openings op1 and op2 is formed on the entire display area in the array substrate 202, and the pixel electrode ( 260 is formed in each pixel region P in a plate shape to generate a fringe field by the first and second openings op1 and op2 of the common electrode 270 and the pixel electrode 260. However, this configuration also has the same shape as the pixel electrode and the common electrode arranged alternately with each other with the finger shape, as in the modification of the first embodiment, so that the common electrode and the pixel electrode adjacent to each other generate a transverse electric field. It may be formed to have a configuration.

 The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit of the present invention.

1 is a simplified cross-sectional view of a reflection area and a transmission area of a conventional transverse electric field mode reflection type liquid crystal display device.

2A and 2B are schematic views showing the driving principle of the USH mode liquid crystal in the reflective transmissive liquid crystal display device according to the present invention.

3B and 3C are schematic views illustrating driving principles of the USH mode liquid crystal in the reflective transmissive liquid crystal display device according to the present invention.

4 is a plan view of one pixel area of a transverse electric field mode reflective transmissive liquid crystal display device according to a first embodiment of the present invention;

FIG. 5 is a cross-sectional view of one pixel area of a transverse electric field mode reflective transmission liquid crystal display device according to a first embodiment of the present invention; FIG.

6 is a cross-sectional view of one pixel area of a transverse electric field mode reflective transmissive liquid crystal display device according to a second embodiment of the present invention;

<Description of Symbols for Main Parts of Drawings>

101: transverse electric field mode reflection transmission type liquid crystal display device

102 array substrate 106 gate electrode

110: first storage electrode 115: gate insulating film

120: semiconductor layer 120a: active layer

120b: ohmic contact layer 125: data wiring

130: source electrode 133: drain electrode

136: first protective layer 140: second protective layer

142: third protective layer 150: reflecting plate

152: fourth protective layer 160: pixel electrode

163: fifth protective layer 170: common electrode

172: first alignment layer 181: color filter substrate

183: Black matrix 185: color filter layer

187: overcoat layer 189: second alignment layer

190: USH mode liquid crystal layer 193: first polarizing plate

195: second polarizing plate

op1, op2: first and second openings P: pixel area

RA: reflection area TA: transmission area

Tr: Thin Film Transistor TrA: Device Area

Claims (11)

A first substrate having a common electrode and a pixel electrode formed in a pixel region having a reflection region and a transmission region, a second substrate facing the color filter layer, and a liquid crystal layer interposed between the two substrates; In the transverse electric field mode reflection-transmitting liquid crystal display device having a pixel electrode and a common electrode which are alternately disposed in the reflection area and the transmission area, and alternate with each other, A first alignment layer disposed on an inner surface of the first substrate and aligned in a first direction; A second alignment layer disposed on an inner surface of the second substrate and aligned in a first direction in the same manner as the first alignment layer; The liquid crystal layer has a spiral structure in which chiral nematic liquid crystal molecules of short pitch are twisted several times in a voltage-off state to the common electrode and the pixel electrode, and the spiral axis is an optical axis. and an optical axis inclined with respect to the spiral axis by rearranging liquid crystal molecules forming a spiral in a voltage-on state of the common electrode and the pixel electrode. A transverse electric field mode reflective transmission liquid crystal display device characterized by comprising a USH mode liquid crystal having a birefringence characteristic. The method of claim 1, And the optical axis is inclined to have an angle of 20 degrees to 60 degrees with respect to the spiral axis when the voltage is applied. The method of claim 2, And wherein the maximum inclination of the optical axis inclined with respect to the spiral axis in the reflection area and the transmission area is different from each other. The method of claim 1, A gate wiring and a data wiring formed on the inner surface of the first substrate to define the pixel region by crossing each other with a gate insulating film interposed therebetween; A common wiring formed in parallel with the gate wiring; A thin film transistor connected to the gate line and the data line in the pixel area; A first passivation layer covering the data line and the thin film transistor; A reflection plate formed in the reflection area over the first protective layer; A second protective layer formed over the reflecting plate; The pixel electrode in contact with the drain electrode through a drain contact hole exposing the drain electrode of the thin film transistor over the second passivation layer and formed in a plate shape in the pixel region; A third passivation layer formed over the pixel electrode; A plurality of first openings connected to the common protective layer through the common contact hole on the third passivation layer and spaced apart from each other in the transmissive area with a long axis in a second direction, and in the reflective area with a long axis in a third direction The common electrode including a plurality of spaced apart second openings Transverse electric field mode reflective transmission liquid crystal display device comprising a. The method of claim 1, A gate wiring and a data wiring formed on the inner surface of the first substrate to define the pixel region by crossing each other with a gate insulating film interposed therebetween; A common wiring formed in parallel with the gate wiring; A thin film transistor connected to the gate line and the data line in the pixel area; A first passivation layer covering the data line and the thin film transistor; A reflection plate formed in the reflection area over the first protective layer; A second protective layer formed over the reflecting plate; Contacting the drain electrode through a drain contact hole exposing the drain electrode of the thin film transistor to the upper portion of the second passivation layer, and having a plurality of bars in each of the transmissive areas in a second direction and spaced apart from each other; A plurality of pixel electrodes formed in the reflection areas and spaced apart from each other in a third direction; A third passivation layer formed over the pixel electrode; A plurality of common electrodes connected to the common pass through the common wiring through the common contact hole on the third passivation layer, and alternately spaced apart from the plurality of pixel electrodes in the reflection area and the transmission area, respectively; Transverse electric field mode reflective transmission liquid crystal display device comprising a. The method according to claim 4 or 5, And a first polarizing plate and a second polarizing plate disposed on outer surfaces of the first and second substrates, respectively, and having polarization axes perpendicular to each other. 6. The method according to any one of claims 1 to 5, And the liquid crystal layer has a thickness different in a reflection area and a transmission area. The method of claim 7, wherein And the thickness of the liquid crystal layer in the transmission region is twice the thickness of the liquid crystal layer in the reflection region. 6. The method according to any one of claims 1 to 5, And the liquid crystal layer has the same thickness in the reflection area and the transmission area. The method of claim 9, And a λ / 4 phase difference plate on the reflective plate in the reflective region of the first substrate. The method of claim 1, And wherein the color filter layer is patterned and removed at a central portion of the color filter layer to form a transmission hole.

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