KR19990038180A - Liquid crystal display device having a new liquid crystal driving method - Google Patents

Abstract

A liquid crystal display device having a different electrode arrangement. A transparent planar electrode is formed on the inner surface of the substrate in the lateral direction, and an insulating film covers the electrode. On the insulating film, a plurality of transparent or opaque stripe electrodes are formed parallel to each other in the longitudinal direction. When a voltage is applied between two electrodes to give a potential difference between the two electrodes, a parabolic or semi-elliptic electric force line symmetrical about the longitudinal center line on the stripe electrode and the longitudinal center line of the area between the stripe electrodes, Is formed. These lines of electric force have vertical and horizontal components on the boundary line between the two electrodes and the two electrodes, and the liquid crystal molecules are rearranged with the twist angle and the tilt angle by the electric field. Due to the rearrangement of the liquid crystal molecules, the polarization of the incident light changes, and the display operation becomes possible.

Description

Liquid crystal display device having a new liquid crystal driving method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new driving type liquid crystal display device and a driving method thereof.

2. Description of the Related Art In general, a liquid crystal display device is a display device having an electrode on the inner surface of both substrates or one substrate and having a layer of a liquid crystal material between two electrodes as an optical switching medium. When a potential difference is given to both electrodes, Arranged and rearranged liquid crystal molecules display an image by scattering light or changing the transmission characteristics of light.

As an example of a conventional liquid crystal display device, a nematic liquid crystal material is inserted between an upper electrode and a lower electrode formed on inner surfaces of two lower substrates, and liquid crystal molecules are aligned in parallel to the substrate And a twisted nematic liquid crystal display device disclosed in Japanese Patent No. 5,576,861. In this liquid crystal display device, when a voltage is applied to the lower electrode to give a potential difference, an electric field perpendicular to both substrates is formed, and a torque (the magnitude of this torque is an electric field The liquid crystal molecules are rearranged so that the elastic torque generated by the alignment treatment such as torque and rubbing due to the dielectric anisotropy and arranged to orient the major axis direction of the liquid crystal molecules in a specific direction is balanced.

Another example of a conventional liquid crystal display device is disclosed in U. S. Patent No. 5,598, 285 in which two line-shaped electrodes are arranged in parallel on one substrate, a liquid crystal material layer is interposed therebetween, and liquid crystal molecules are aligned in parallel to the substrate For example, a liquid crystal display device. In this liquid crystal display device, a potential difference is given between the electrodes to form an electric field essentially in parallel with the substrate and perpendicular to the two electrodes, and the liquid crystal molecules are aligned in the direction of the liquid crystal so that the torque due to the dielectric anisotropy of the liquid crystal material and the elastic torque The molecules rearrange.

These conventional liquid crystal display devices each have a problem.

The biggest problem of the twisted nematic liquid crystal display device is that the viewing angle is narrow. In this liquid crystal display device, as the angle between the direction of the eye of the person looking at the display device and the direction perpendicular to the surface of the display device becomes larger, the birefringence (n), which is the difference in refractive index between the long axis direction and the short axis direction, The value of the product of the thickness d of the liquid crystal layer, that is,? N · d becomes large, and the contrast is rapidly lowered as compared to the contrast (the value obtained by dividing the luminance in the brightest state by the luminance in the darkest state). In addition, the phenomenon of gradation reversal, in which the brightness is reversed, also appears. Therefore, the viewing angle (the angle at which the contrast is normally maintained at 10 is called a viewing angle) is very narrow, and when viewing the display device at an angle larger than the viewing angle, the image quality deteriorates sharply as compared with an image viewed from the front.

In order to compensate for the viewing angle, a method of widening the viewing angle by using a retardation compensating plate or the like is proposed as described in the above-mentioned U.S. Patent No. 5,576,861, but an additional step of attaching an additional compensating plate is required Not only are costs increased and processes increasing, but even with compensation plates, the limits of viewing angle remain.

In the second device, since the electric field located in the region between the two electrodes becomes smaller as the distance from the two electrodes increases, not only the minimum voltage (threshold voltage) for passing light in the normally black mode is high, (Saturation voltage) which is high enough to allow the power supply to pass through, or the power consumption increases as a whole. In addition, not only all the electrodes are formed on a single substrate but also a portion where the pixel electrode and the common electrode are overlapped with each other with the insulating film interposed therebetween, so that the aperture ratio through which the light passes is small.

An object of the present invention is to secure a wide viewing angle.

Another object of the present invention is to drive a liquid crystal at a low voltage to lower power consumption.

Another object of the present invention is to increase the aperture ratio.

1 is a layout diagram showing an electrode of a liquid crystal display device according to a first embodiment of the present invention,

FIG. 2 is a cross-sectional view taken along the line II-II 'in FIG. 1, showing equipotential lines and electric lines of force between the upper substrate and the lower substrate,

3 is a view for explaining a twist angle change of liquid crystal molecules in the first embodiment of the present invention,

4 is a graph showing a twist angle change of liquid crystal molecules with respect to a line which is horizontal to the substrate and perpendicular to the stripe electrode in the first embodiment of the present invention,

5 is a graph showing a twist angle change of liquid crystal molecules with respect to a vertical line of the substrate in the first embodiment of the present invention,

6 is a view for explaining a change in the inclination angle of liquid crystal molecules in the first embodiment of the present invention,

7 is a graph showing a twist angle change of liquid crystal molecules with respect to a vertical line of the substrate in the first embodiment of the present invention,

8 is a graph showing a change in the inclination angle of the liquid crystal molecules with respect to a line that is horizontal to the substrate and perpendicular to the stripe electrode in the first embodiment of the present invention,

9 is a graph showing a change in transmittance according to a position in a liquid crystal display device according to the first embodiment of the present invention,

10 is a graph showing a change in transmittance according to an applied voltage in the liquid crystal display according to the first embodiment of the present invention,

11 is a graph showing a viewing angle in a liquid crystal display device according to the first embodiment of the present invention,

12 is a layout diagram of a liquid crystal display device according to a second embodiment of the present invention,

13 is a cross-sectional view cut along the line XIII-XIII 'of Fig. 12,

14 is a layout diagram of a liquid crystal display device according to the third embodiment of the present invention,

15 is a cross-sectional view taken along line XV-XV 'in Fig. 14,

16 is a cross-sectional view taken along line XV-XV 'in Fig.

In order to solve the above problems, the present invention renders the arrangement of electrodes.

That is, the first electrodes and the second electrodes, which are insulated from each other, are arranged so that their edges are overlapped with each other, and the second electrode has a structure of continuous surfaces between the first electrodes, The first electrode and the second electrode.

In such a liquid crystal display apparatus, an electric field is generated when a voltage is applied to the first electrode and the second electrode to give a potential difference. The shape of the electric force line is a semi-elliptic or parabolic shape centered on the boundary line or boundary region between the first electrode and the second electrode So that the electric field also has vertical and horizontal components on each electrode.

The liquid crystal molecules in the boundary region between the first electrode or the second electrode and between the two electrodes are rearranged with a torsional angle and a tilt angle due to the horizontal and vertical components of the electric field and the polarization of the light is changed by the rearranged liquid crystal material layer do.

Since the liquid crystal molecules are rearranged with both twist angle and inclination angle, the viewing angle is widened.

In addition, since the electric field has vertical and horizontal components on the first electrode and the second electrode as well as the boundary region between the two electrodes, the liquid crystal molecules on the first electrode and the second electrode are also involved in the display of the image.

Further, since the intensity of the electric field is large in the boundary region between the first electrode and the second electrode, power consumption is low because the threshold voltage and the saturation voltage for driving the liquid crystal layer thereon are low.

In addition, when a thin film transistor is provided as a switching element to apply a voltage to the first electrode and the second electrode, since the two electrodes overlap each other with the insulating film interposed therebetween, there is no need to separately provide a storage capacitor to secure the capacitance, Can be greatly increased.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains.

First, a first embodiment of the present invention will be described in detail with reference to Figs. 1 to 11. Fig.

FIG. 1 is a view showing the arrangement of electrodes in the liquid crystal display device according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II ' And the electric lines and equipotential lines are shown together.

First, the structure of the lower substrate on which the electrodes are formed will be described.

On the inner surface of the lower substrate 10 made of transparent insulating material such as glass or quartz, a planar electrode 2 having a certain width is formed in a transverse direction and made of a transparent conductive material such as ITO (indium tin oxide). A plurality of striped electrodes 1 having a narrow width are formed on the insulating layer 3 on the surface electrode 2 in parallel with each other in the longitudinal direction. The striped electrode 1 can be used as a transparent or opaque material and its width is smaller than the distance between the stripe electrodes 1, i.e. the distance between the adjacent border lines of the adjacent two stripe electrodes 1. [ An alignment film 30 made of a material such as polyimide is applied on the stripe electrode 1. On the other hand, a polarizing plate 20 is attached to the outer surface of the lower substrate 10.

On the inner surface of the upper substrate 11 made of transparent insulating material such as glass or quartz, an orientation film 31 made of a material such as polyimide is formed, and a polarizer 21 is attached to the outer surface.

Finally, a liquid crystal material layer having optical anisotropy is inserted between the alignment films 30 and 31 of the two substrates 10 and 11.

The liquid crystal display device may perform a display operation by adjusting the transmittance of light from a backlight unit (not shown) located below the lower substrate 10, The display operation can be performed using natural light. In this case, the lower polarizer 20 is not necessary. In the case of a reflection type liquid crystal display device using natural light, it is preferable that the striped electrode 1 and the surface electrode 2 are made of a material such as opaque and high reflectance material such as aluminum (Al).

Hereinafter, a general form of the electric field of the liquid crystal display device will be described in detail with reference to FIG.

When a voltage is applied to the two electrodes 1 and 2 to give a potential difference between the two electrodes 1 and 2, an electric field as shown in FIG. 2 is generated. The solid line in Fig. 2 shows the equipotential line, and the dotted line shows the electric line of force.

2, the shape of the electric field is formed by a longitudinal center line C (actually corresponding to the plane) of the narrow region NR on the stripe electrode 1 and a wide region WR between the stripe electrodes 1, (In actuality, the face) of the center line B in FIG. The area between the center line C of the narrow area NR and the center line B of the wide area WR is divided into a narrow area NR and a wide area WR by a boundary line A (actually, An electric field having the form of an electric force line of an elliptical shape or a parabolic shape (hereinafter referred to as semi-elliptical shape for convenience) is formed. The tangential line of the electric force line is substantially parallel to the substrate 10 on the boundary line A of the narrow region NR and the wide region WR and is parallel to the substrate 10 in the central region of the narrow region NR and the wide region WR. Lt; / RTI > The center and vertical vertices of the ellipse are located on the boundary line A between the narrow region NR and the wide region WR and the two vertices in the horizontal direction are located in the wide region WR and the narrow region NR, do. At this time, since the distance from the center of the ellipse is shorter than the horizontal vertex located in the wide region (WR), the ellipse is not symmetrical with respect to the boundary line (A). Also, the density of the electric lines varies with the position, and the intensity of the electric field also changes proportionally. Therefore, the electric field strength is greatest on the boundary line AA between the narrow region NR and the wide region WR, and the intensity of the electric field becomes larger toward the center lines CC and BB of the narrow region NR and the wide region WR, And becomes smaller toward the substrate 11.

The state in which the liquid crystal molecules are rearranged by the electric field is divided into a horizontal component and a vertical component.

First, an initial state will be described.

The two alignment films 30 and 31 are aligned by rubbing or ultraviolet irradiation so that all of the liquid crystal molecules are arranged in one direction but are almost horizontal although they have a slight angle of inclination with respect to the substrates 10 and 11, And 11 are arranged so as to form an angle with respect to the direction of the stripe electrode 1 and the direction perpendicular thereto. The polarization axes of the polarizers 20 and 21 are arranged to be orthogonal to each other, and the polarization axes of the lower polarizers 20 substantially coincide with the rubbing direction. The liquid crystal material contained between the two alignment films 30 and 31 is a nematic liquid crystal having a positive dielectric anisotropy.

Next, a voltage is applied to the stripe electrode 1 and the surface electrode 2, respectively, and a high voltage is applied to the stripe electrode 1. In this case, the arrangement of the liquid crystal molecules is determined by the equilibrium between the force due to the electric field (depending on the direction and intensity of the electric field) and the elastic restoring force caused by the alignment treatment.

The rearrangement state of the liquid crystal molecules is divided into a component parallel to the substrate and a component perpendicular to the substrate. For convenience of explanation, let the direction perpendicular to the substrate be the z-axis, the direction perpendicular to the substrate and perpendicular to the direction of the stripe electrode 1 be the x-axis, and the direction parallel to the direction of the stripe electrode 1 be the y-axis. 1, the direction from left to right is referred to as x-axis, the direction from bottom to top along the stripe electrode 1 is referred to as y-axis, and the direction from the lower substrate 11 to the upper substrate 10 in Fig. 2 is z Let's take the axis.

First, the twist angle of the liquid crystal molecules, that is, the angle formed by the long axis of the liquid crystal on the plane parallel to the substrate, that is, the xy plane with respect to the x axis or the initial alignment direction will be described with reference to FIGS. 3, 4 and 5.

As shown in Fig. 3, the rubbing direction is a vector , The xy plane component of the electric field is vector And the optical axis of the lower polarizer 20 is a vector , And an angle formed between the rubbing direction and the x axis is represented by? _R , and an angle between the long axis of the liquid crystal molecule and the x axis is represented by? _LC . Here, the optical axis of the lower polarizer 20 corresponds to the rubbing direction, and therefore the angle ψ _P = ψ _R that the optical axis of the lower polarizer 20 makes with the x-axis.

Xy plane component of electric field Direction from the boundary line A to the center line B of the wide area WR and the negative x direction from the center line B to the next boundary line D of the wide area WR. The intensity of the electric field component is greatest on the boundary lines A and D, becomes smaller toward the center line BB, and becomes zero on the center line BB.

The magnitude of the elastic restoring force by the alignment treatment is constant regardless of the position on the xy plane.

As shown in FIG. 4, in the boundary lines (A and D), the liquid crystal molecules are arranged such that the major axis direction of the liquid crystal molecules is parallel to the electric field component (? _{R -} ? _LC ) formed by the long axis of the liquid crystal molecules with respect to the rubbing direction toward the center lines C and B of the regions NR and WR is approximately parallel to the rubbing direction, And the long axis and the rubbing direction of the liquid crystal molecules become the same in the center lines B and C, respectively. Since the optical axis of the lower polarizing plate 20 is parallel to the rubbing direction, the angle formed by the optical axis of the lower polarizing plate 20 and the long axis of the liquid crystal molecules also has the same distribution, and this value is closely related to the light transmittance.

Various types of electric fields can be produced by changing the ratio of the widths of the narrow region NR and the wide region WR. When the stripe electrode 1 is an opaque electrode, a narrow region NR on the stripe electrode 1 can not be used as a display region. However, when the stripe electrode 1 is made of a transparent material, a narrow region NR can also be used as a display region .

On the other hand, the xy plane component The elastic restoring force due to the alignment is greatest on the surface of the alignment films 30 and 31 and the alignment films 30 and 31 ) Of the liquid crystal layer.

5, the twist angle of the liquid crystal molecules in the direction from the lower alignment layer 30 to the upper alignment layer 31, that is, along the z axis and along the major axis direction of the liquid crystal molecule with the x axis is shown in Fig. And the cell interval is d. Here, the horizontal axis represents the height from the lower alignment layer 30, and the vertical axis represents the twist angle.

5, the twist angle is large on the surface of the alignment films 30 and 31 because the force due to the alignment force is strong, and becomes smaller toward the center of the liquid crystal layer and becomes closer to the direction of the electric field. 31), the long axes of the liquid crystal molecules are aligned in the same direction as the rubbing direction. Here, when the difference in twist angle of adjacent liquid crystal molecules is referred to as twist, the twist in FIG. 5 corresponds to the slope of the curve, which is larger at the surface of the alignment films 30 and 31 and smaller toward the center of the liquid crystal layer.

Next, with reference to FIGS. 6, 7, and 8, the change in angle formed on the plane perpendicular to the substrate, such as the zx plane, with respect to the inclination angle of the liquid crystal molecules, that is, the x axis or the initial alignment direction, Explain. 6 shows only the substrates 10 and 11 for the sake of convenience, and is a vector showing the rubbing direction shown in Fig. 3 The component for the zx plane of the vector , The zx plane component of the electric field is the vector , And the zx plane component of the electric field The x-axis and the angle θ is to _E, shows the inclination angle of the major axis of liquid crystal molecules constituting the x-axis to the θ _LC. However, (The ignition angle is ignored) Is in the x direction.

Zx plane component of electric field The smaller the angle θ _E is from the lower substrate 10 toward the upper substrate 11, and the smaller the angle θ _{E from} the lower substrate 10 toward the upper substrate 11.

As described above, the magnitude of the elastic restoring force due to the alignment treatment is the largest on the surfaces of the two substrates 10 and 11, and becomes smaller toward the center of the liquid crystal layer.

The liquid crystal molecules should be arranged so that these two forces are in equilibrium. As shown in Figure 7, because the substrate 10 surface, the alignment force down the river in size because the liquid crystal molecules are gradually arranged in parallel with the x axis, but higher than the top of the force due to the electric field is relatively larger as the inclination angle (θ _LC) which And then it is decreased again and arranged on the surface of the upper substrate 11 again in parallel with the x-axis. At this time, the apex of the curve appears near the lower substrate 10.

On the other hand, the zx plane component The angle &thetas; _E with respect to the x axis is close to 0 on the boundary lines A and D and becomes larger toward the center line BB, and the zx plane component of the electric field Is the largest on the boundary lines (A, D) and becomes smaller toward the center line (BB) side,

The magnitude of the elastic restoring force by the alignment treatment is constant regardless of the position on the x-axis.

8, the inclination angle of the liquid crystal molecules is almost zero at the boundary lines A and D, but becomes larger toward the center lines C and B, so that the zx plane component of the electric field Has a distribution similar to the angle (? _E ) with the x-axis. However, it changes more slowly than θ _E.

When a voltage is applied to the two electrodes 1 and 2, the liquid crystal molecules are rearranged with a twist angle and a tilt angle, and the transmittance of light changes due to the change of the twist angle and the tilt angle. On the boundary lines (A, D), there is little change in the tilt angle when viewed along the z-axis, but the change in twist angle is large. On the other hand, there is little change in the twist angle along the z-axis on the center lines B and C, but the tilt angle slightly changes. Therefore, in the region between the boundary lines A and D and the center lines B and C, the torsion angle and the tilt angle both change. As a result, the transmittance curve according to the position is similar to the shape of the electric line of force.

The transmittance and the viewing angle characteristics of the liquid crystal display device according to the first embodiment of the present invention will be described with reference to FIGS. 9, 10, and 11. FIG.

In this experimental example, the stripe electrode 1 is made of an opaque material, the width of the narrow region NR is 5 占 퐉, the width of the wide region is 17 占 퐉, the voltage applied to the planar electrode 2 is 0V, 1) was 5 V, ψ _R was 80 °, the pretilt angle was about 1.5 °, and the cell spacing was 4.5 μm.

FIG. 9 is a graph of transmittance according to this experimental example. In FIG. 3, the leftmost stripe electrode 1 of FIG.

9, the transmittance becomes 0 in the opaque narrow region NR, decreases in the vicinity of the center line B of the wide region WR, decreases in the region between the boundary lines A and D and the center line B, It becomes the maximum in the center.

As shown in FIG. 10, which shows the abscissa as the applied voltage and the ordinate as the transmittance, the threshold voltage is about 1.5V and the saturation voltage is about 3V. Therefore, the liquid crystal display device according to the present invention can be driven with a low voltage.

FIG. 11 is a graph showing the viewing angle characteristics according to the direction of the liquid crystal display device according to the present embodiment, and it can be seen that the boundary of the area of contrast 10 or more is almost 60 degrees above and below and left and right.

In the present experimental example, a wider viewing angle can be obtained by using an optical retardation compensation plate between the polarizing plate and the substrate.

In the foregoing Examples and Experimental Examples, the kind of the liquid crystal material, the kind of the orientation film, the orientation method, the angle of incidence, the direction of the polarizer, the cell spacing, the kind and presence of the retardation compensator, Can be changed according to the design of the liquid crystal display device.

For example, when the striped electrode 1 is formed of a transparent material, liquid crystal molecules on the striped electrode 1 are also used for controlling light, so that a higher transmittance can be obtained.

Next, a liquid crystal display device according to a second embodiment of the present invention will be described with reference to Figs. 12 and 13. Fig.

In this embodiment, unlike the first embodiment, portions where the two electrodes overlap are removed. However, the surface electrodes 2 of two neighboring pixels must be connected to each other. This connection portion may overlap the striped electrode 1 as shown in FIG. 12, but may be formed outside the striped electrode 1 so as not to overlap It is possible. 12, only the middle portion of the portion of the surface electrode 2 which overlaps with the stripe electrode 1 is removed to form the opening portion 5, and the lower portion of the overlapped portion for signal transmission is left as it is. The region on the stripe electrode 1 is defined as a narrow region NR and the region where the opening 5 is located is referred to as a boundary region BR and the region occupied by the portion of the surface electrode 2 between the two adjacent openings 5 is referred to as Let the width of the narrow region NR be c, the width of the boundary region BR be b, and the width of the wide region WR be b.

13, which is a cross-sectional view taken along line XIII-XIII 'in FIG. 12, the electric line of force is generated in the form of a parabola or semi-ellipse between the center line C of the narrow region NR and the center line B of the wide region WR. When the width c of the boundary region BR is constant, a parabolic line of electric force is obtained in which the apex is located on the center line I of the boundary region BR substantially in accordance with the value of a / b. The shape of a parabola is asymmetric when a and b are different, but is almost symmetric when a and b are the same. Here, when c is 0, an electric field substantially similar to that of the first embodiment is formed. Even if c is not 0, an electric field having horizontal and vertical components is formed on the surface electrode 2 or the stripe electrode 1.

Accordingly, in a transmissive display device in which one or both electrodes are formed of a transparent material, light passing through the transparent electrode is controlled by twisting and tilting of the liquid crystal layer located on the electrode. At this time, the threshold voltage of the liquid crystal material becomes lower as the c value becomes smaller.

In the case of a reflection type in which both the electrodes (1, 2) are used as a metal having a high reflectance, for example, a metal such as Al, the smaller the c, the higher the reflectance. In this case, as described above, the liquid crystal layer on the rearranged electrode with the twist angle and the tilt angle change changes the polarization of the light incident on the electrode and the light reflected on the electrode to display an image.

Next, as a third embodiment of the present invention, a liquid crystal display device in which a thin film transistor is added as a switching element to the structure of the electrode shown in the first and second embodiments is described with reference to Figs. 14 to 16 do.

Fig. 14 is a layout diagram of one pixel formed on the lower substrate of the liquid crystal display device according to the present embodiment. In a liquid crystal display device, hundreds of thousands of such pixels are arranged in a matrix structure.

A horizontal scanning signal line 40 is formed on a transparent insulating substrate 10 and a horizontal common electrode 2 is formed between the scanning signal lines 40.

The scanning signal line 40 and the common electrode 2 are covered with a gate insulating film 3. A part of the gate insulating film 3 located on the scanning signal line 40 (Not shown). On the amorphous silicon layer 60, amorphous silicon layers 71 and 72 doped at a high concentration with n-type impurities are formed on both sides of the gate electrode 41, respectively.

On the other hand, a data line 80 is formed in the longitudinal direction on the gate insulating film 3 so as to intersect with the gate line 40, and a part of the data line 80 is formed to be formed on the doped amorphous silicon layer 71 And a drain electrode 82 is formed on the doped amorphous silicon layer 72 located on the opposite side of the source electrode 81 with respect to the gate electrode 41. The gate electrode 41, the source electrode 81 and the drain electrode 82 constitute each electrode of the thin film transistor. A channel through which the electrons move is formed in the amorphous silicon layer 60, and a doped amorphous silicon layer, Drain electrodes 81 and 82 and the amorphous silicon layer 60. In this case,

The drain electrode 82 extends to form a plurality of striped pixel electrodes 1 and the data lines 80 and the source and drain electrodes 81 and 82 and the pixel electrode 1 are covered with a protective film 90, and an alignment film 30 is formed thereon.

Here, the common electrode 2 must be connected to the common electrode of the neighboring pixel since the common electrode signal must be received from the common electrode of the neighboring pixel. In order to do so, the common electrode 2 and the data line 80 are superimposed, and this overlapping portion generates a parasitic capacitance, thereby increasing the RC delay of the image signal. In order to reduce this, the overlapping area of the common electrode 2 and the data line 80 should be minimized, and a portion of the common electrode 2 positioned below the data line 80 overlapping the data line 80 is removed . However, the lower part of the overlapped portion is left as it is so that the connection with the common electrode of the neighboring pixel is not cut off.

Further, the protective film 90 is removed in the display region, that is, the portion where the pixel electrode 1 and the common electrode 2 are located, so that a sufficient electric field can be generated.

Hereinafter, a method for manufacturing the liquid crystal display device according to the third embodiment of the present invention will be described in detail.

First, a transparent conductive material such as ITO is laminated and patterned to form a common electrode 2. Then, a Cr, Al, Mo, Ti, or Ta film or an alloy film thereof is deposited and patterned to form the scanning signal line 40 and the gate electrode (41). A gate insulating film 3 made of a material such as a nitride film is stacked to cover the common electrode 2 and the gate electrode 41 and the scanning signal line 40 and the amorphous silicon layer 60 and the n + The silicon layers 71 and 72 are successively laminated. The n + type amorphous silicon layers 71 and 72 and the amorphous silicon layer 60 are patterned to deposit the Cr, Al, Mo, Ta, or their alloys and pattern them to form the data lines 80, the source electrodes 81, The drain electrode 82 and the pixel electrode 10 are formed and then the n + type amorphous silicon layers 71 and 72 exposed by using them as masks are etched to complete the ohmic contact layers 71 and 72. [ Next, a protective film 80 is deposited and patterned to form an opening on the pixel electrode 1, and then the alignment film 30 is applied to complete the substrate for a liquid crystal display according to the present embodiment.

The present invention is not limited to the embodiments described above, and technical contents that can be modified or improved by those skilled in the art based on these embodiments are also included in the present invention.

In such a liquid crystal display device, by renewing the electrode structure, the viewing angle can be widened, the driving voltage can be lowered, and the aperture ratio can be increased.

Claims (13)

The first and second substrates facing each other, A first electrode formed on the first substrate, And a second electrode formed on the first substrate so as to be insulated from the first electrode and overlapped at least partially with the first electrode and having a continuous surface between the first electrodes, And one pixel includes at least one of the first electrodes and the second electrode. The method of claim 1, And the second electrode is connected to adjacent pixels. 3. The method of claim 2, Wherein the first electrode and the second electrode are formed of a transparent conductor. The method of claim 1, Wherein the first electrode or the second electrode is formed of a transparent conductor. First and second substrates facing each other, A liquid crystal material layer sealed between the first and second substrates, And first and second electrodes formed on the first substrate and electrically insulated from each other, At least a portion of the liquid crystal molecule region in which the liquid crystal molecules of the liquid crystal material layer are rearranged by an electric field generated by applying a voltage to the first and second electrodes is formed on the first electrode or the second electrode, And the liquid crystal molecular region formed on the second electrode is a part of the image display region. The method of claim 5, Wherein the liquid crystal molecules in the liquid crystal molecule region have a twist angle and an inclination angle. The method of claim 5, Wherein the first electrode and the second electrode are overlapped at least partially. The method according to claim 5 or 6, Wherein the electric field has a parabolic electric line of force located between the first electrode and the second electrode, and the electric line of force has vertical and horizontal components on the first electrode or the second electrode. The method according to claim 5 or 6, Wherein a line width of the first electrode is larger than a line width of the second electrode and a liquid crystal molecular region on the first electrode is a part of the image display region. The method of claim 9, Wherein the first electrode is made of a transparent conductive material. 11. The method of claim 10, And a polarizer attached to an outer surface of the first and second substrates, respectively, wherein light passing through one of the polarizers passes through the image display area to reach another polarizer. The first and second substrates facing each other, A liquid crystal material layer sealed between the first and second substrates, A plurality of scanning signal lines and data lines formed to be electrically insulated from each other on the first substrate and intersecting with each other, A plurality of thin film transistors each having a gate electrode connected to the scan signal line, a source electrode connected to the data line, and a drain electrode, A pixel electrode connected to the drain electrode of the thin film transistor, And a common electrode electrically insulated from the pixel electrode, Wherein the thin film transistor switches a voltage from the data line by a signal from the scanning signal line and sends the voltage to the pixel electrode and generates a liquid crystal molecule of the liquid crystal material layer by an electric field generated by applying a voltage to the pixel electrode and the common electrode Wherein at least a portion of the liquid crystal molecule region in which the liquid crystal molecules are rearranged is formed on the first electrode or the second electrode and the liquid crystal molecule region formed on the first electrode or the second electrode is a part of the image display region. The method of claim 12, Wherein the pixel electrode and the common electrode are partially overlapped to form a storage capacitor.