KR101001948B1 - Multi-domain liquid crystal display device - Google Patents

Abstract

The active matrix type multi-domain vertical alignment liquid crystal display device according to the present invention is arranged in a matrix form and includes a plurality of pixel electrodes including a first sub-pixel electrode and a second sub-pixel electrode, and a first switching connected to the pixel electrode It includes an element and a second switching element, a gate line connected to the switching element, a data line intersecting the gate line and connected to the switching element and transmitting a data voltage. A liquid crystal having a positive dielectric anisotropy is injected into a liquid crystal display device having such a structure, and initial vertical alignment is performed. The first subpixel electrode and the second subpixel electrode are driven by the first switching element and the second switching element, respectively. At this time, the voltage applied to the second switching element has the same magnitude as the voltage applied to the first switching element, but a voltage having the opposite polarity is applied. Therefore, although the magnitude of the voltage applied to each pixel is small, the potential difference between the two sub-pixel electrodes is doubled, so that a small voltage may have a large potential difference.

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Description

Multi-domain liquid crystal display {MULTI-DOMAIN LIQUID CRYSTAL DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-domain liquid crystal display device, and relates to a liquid crystal display device that induces stable movement of a liquid crystal using a liquid crystal mixture having a low viscosity and a high dielectric anisotropy while reducing the complexity of a process.

The display market has made great strides in recent years. The display industry, which occupies an important position in various fields such as mobile, laptop, monitor, and TV, has come to develop displays that are lighter, thinner, and sharper to meet the needs of consumers. In line with this trend, the demand for flat panel displays (FPDs) has increased rapidly, and compared to many other FPDs, TFT-LCD (thin film transistor-liquid crystal display) has high resolution, ultra light weight, ultra slim, low power consumption, etc. It has several advantages.
However, TFT-LCD has various problems such as low transmittance, which is a chronic problem, and uneven luminance and color characteristics according to viewing angle. To solve this problem, various modes such as a patterned vertical aligned (PVA) mode, a fringed field switching (FFS) mode, an in-plane switching (IPS) mode, a biased vertical aligned (BVA) mode, and a VA-IPS mode have been proposed.
In particular, the PVA mode has high visibility for each gradation and a high response speed, but the process is rather complicated and complicated because it is necessary to form patterns on both the upper substrate electrode and the lower substrate electrode. In addition, the PVA mode uses a liquid crystal with a negative dielectric anisotropy, so the rotational viscosity is fundamentally high, and the driving voltage is high and the response speed is limited. The PVA mode is disclosed in the document "Journal of Information Display. 1 3 (2000)". To improve the visibility of the PVA mode, an S-PVA (Super-patterned vertical aligned) mode was developed. In the S-PVA mode, a pixel electrode is divided into two sub-pixel electrodes, and different voltages are applied to make liquid crystal molecules between sub-pixels move differently so that optical compensation can be performed. As a result, although the degree of color change according to the viewing angle is reduced than the PVA mode, there is a disadvantage that two thin film transistors are used. The S-PVA mode is disclosed in the document "SID Symposium Digest Tech Papers 35 760 (2004)".

In addition, in the case of the IPS mode, although there is an effect of improving the motion and transmittance of the stable molecule, the difficulty of the process and various defect factors are potential due to the addition of the rubbing process. IPS mode is disclosed in the document "Appl. Phys. Lett. 67 26 (1995)".

Looking at the characteristics of the existing PVA mode, first of all, there is a pattern such as a slit on the common electrode of the upper plate, and a pattern is also formed on the pixel electrode of the lower substrate. Therefore, it is somewhat more difficult and complicated than other modes of manufacturing, and requires accuracy of the upper and lower plates when bonding.

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In addition, in the case of the IPS mode, a rubbing process for initial alignment of liquid crystal molecules on the upper and lower substrates is required. As this becomes a more difficult process toward a large area, it may cause defects such as rubbing mura.

Accordingly, an object of the present invention is to provide a liquid crystal display device having a simple manufacturing process, a fast response speed, and excellent visibility.
In addition, another object of the present invention is to provide a liquid crystal display device that does not form a pattern on the common electrode of the top plate and does not require a rubbing process.

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The present invention for solving the above object, in a liquid crystal display device, a liquid crystal layer initially vertically oriented and having a positive dielectric anisotropy, a plurality of pixel electrodes positioned under the liquid crystal layer and arranged in a predetermined pattern, and the liquid crystal A common electrode which is located on the upper layer and has no pattern or is arranged in a different pattern from the pixel electrode, and a switching element connected to the pixel electrode and the common electrode, wherein the pixel electrode and the switching element are one pixel. It is characterized by being provided with a plurality.
In addition, the present invention in the liquid crystal display device, the liquid crystal layer is vertically oriented initially and the dielectric constant anisotropy is positive, a lower alignment layer positioned below the liquid crystal layer and vertically aligning the liquid crystal layer, and located above the liquid crystal layer An upper alignment layer vertically aligning the liquid crystal layer, a plurality of pixel electrodes positioned below the lower alignment layer and arranged in a predetermined pattern, and having a pattern located above the liquid crystal layer or having a different pattern from the pixel electrode Arranged common electrode, the pixel electrode and a switching element connected to the common electrode, a lower polarizing plate positioned below the pixel electrode, and perpendicular to the transmission axis of the lower polarizing plate located above the common electrode An upper polarizing plate having an axis is provided, and a plurality of the pixel electrode and the switching element are provided for one pixel. Alternating voltages of opposite polarities are alternately applied to the plurality of pixel electrodes, and the common electrode of the pixel electrode Another feature is that it is not arranged in the same pattern as the pattern.
In the multi-domain liquid crystal display device according to the present invention, liquid crystal molecules having a positive dielectric anisotropy are initially vertically oriented and do not form a pattern on the upper common electrode to compensate for the disadvantages of the PVA mode. If the pattern is not formed on the upper common electrode, the intensity of the inclined electric field is relatively weak during driving, resulting in unstable and slow movement of liquid crystal molecules. As a result, the response speed and transmittance of the liquid crystal molecules decrease due to the strength of the weak gradient electric field. In the present invention, in order to increase the strength of the gradient electric field, the lower pixel electrode is divided into two sub-pixels and alternately positioned. In addition, horizontal electric fields between sub-pixel electrodes were strongly formed by applying voltages having the same size but opposite polarity to each sub-pixel electrode. As a result, when driving, a weak gradient electric field is formed between the lower pixel electrode and the upper common electrode, and a strong horizontal electric field is formed between the sub-pixel electrodes, and as a result, a strong gradient electric field that is a vector sum of the two electric fields is formed in the cell. However, in order to apply voltages of different polarities to the two sub-pixel electrodes, it is inevitable to use two thin film transistors per pixel.

The multi-domain liquid crystal display device according to the present invention is characterized by having a simple manufacturing process by forming a pattern on the upper common electrode and also removing the rubbing process, having a fast response speed and improved transmittance when driving, and excellent visibility according to viewing angles. do.

The multi-domain vertically aligned liquid crystal display device according to the present invention is arranged in a matrix form, and includes a plurality of pixel electrodes each including a first sub-pixel electrode and a second sub-pixel electrode, which are connected to the first sub-pixel electrode. 1 switching element, a gate line connected to the switching element, and a data line crossing the gate line and connected to the first switching element and transmitting a data voltage. And a second switching element connected to the second sub-pixel electrode, a gate line connected to the switching element and connected to the first switching element, intersecting the gate line, connected to the second switching element, and transmitting a data voltage. It includes the data line. The pixel structure includes first and second switching elements in one pixel, and includes one gate line and a plurality of data lines or a plurality of gate lines and one data line, and is composed of a total of two sub-pixel electrodes. The first and second subpixel electrodes are connected to the first and second switching elements, respectively. Basically, a voltage transmitted from one image information is applied, and data signals having the same potential difference but opposite polarities are given. A horizontal electric field between sub-pixel electrodes was strongly formed by applying a voltage having the same size but opposite polarity to each sub-pixel electrode. As a result, when driving, a weak gradient electric field is formed between the lower pixel electrode and the upper common electrode, and a strong horizontal electric field is formed between the sub-pixel electrodes, and as a result, a strong gradient electric field that is a vector sum of the two electric fields is formed in the cell.

The switching element means a thin film transistor (TFT), which is composed of a gate through which a signal is transmitted from a gate line, a drain through which a signal is transmitted from a data line, and a source through which a signal is transmitted to a pixel electrode. The on/off of the signal transmitted from the source to the source is determined by the gate.

When the present invention is achieved, a rubbing process is also eliminated without forming a pattern on the upper common electrode, thereby realizing a multi-domain liquid crystal display device having a simple manufacturing process and a fast response speed and improved transmittance when driving.

 Hereinafter, a configuration and an operation principle of an embodiment of the liquid crystal display device according to the present invention will be described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described below.

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1 is a block diagram of an overall pixel structure according to the present invention, and one pixel includes a plurality of data lines and one gate line, and positions of the gate line and the data lines may be changed according to a single pixel structure. Data ma and Data mb shown in FIG. 1 are included in one pixel, determine on/off of a voltage transmitted to each sub-pixel electrode, and are obtained from one image information. Data ma is connected to the sub-pixel electrode 101, Data mb is connected to the sub-pixel electrode 103. The gate line and the data line are perpendicular to each other, and they form a gate electrode, a drain electrode, and a source electrode of a switching element connected to one pixel electrode, so that a desired voltage can be applied to the pixel.

Referring to FIG. 2, this is another block diagram of the overall pixel structure according to the present invention, and one pixel includes one data line and two different gate lines. The position of the gate lines may be changed according to the structure of a single pixel. Gate na and Gate nb shown in FIG. 2 are included in one pixel and determine on/off of a voltage transmitted to each sub-pixel electrode, and are obtained from one image information. Gate na is connected to the sub-pixel electrode 101, and Gate nb is connected to the sub-pixel electrode 103. The gate line and the data line are perpendicular to each other, and they form a gate electrode, a drain electrode, and a source electrode of a switching element connected to one pixel electrode, so that a desired voltage can be applied to the pixel.

3A and 3B are pixel equivalent circuit diagrams of an embodiment according to the present invention. FIG. 3A shows a method (1gate-2data) in which two sub-pixels each have a separate data line and shares a gate line, and FIG. 3B shows two sub-pixels sharing one data line and two gate lines. The driving method (2gate-1data) is shown. As illustrated, one pixel is composed of two sub-pixel electrodes (Pixel A, Pixel B), two switching elements directly connected to each sub-pixel electrode (Pixel A, Pixel B), and each of the sub-pixel electrodes And a liquid crystal capacitor (C _lc (A), C _lc (B)) connected to (Pixel A, Pixel B). Also includes two switching elements and a storage capacitor (C _st (A), C _st (B)) connected to the sustain electrode line 500.

The 1gate-2data type liquid crystal panel assembly shown in FIG. 4A includes sub-pixel electrodes 101 and 103 located on the lower substrates of FIGS. 5A and 6A and a common electrode 102 located on the upper substrate of FIG. 7. The 2gate-1data type liquid crystal panel assembly shown in FIG. 4B includes sub-pixel electrodes 101 and 103 located on the lower substrates of FIGS. 5B and 6B and a common electrode 102 located on the upper substrate of FIG. 7.

FIG. 8 is a cross-sectional view of the liquid crystal panel assembly of FIG. 4A taken along line III to III', FIG. 9 is a cross-sectional view of the liquid crystal panel assembly of FIG. 4B along line V to V', and FIG. 10 is of FIG. 4B It is a cross-sectional view of the liquid crystal panel assembly cut along lines IV to IV'.

11 is a view showing the arrangement of liquid crystal molecules before and after the voltage is applied to the multi-domain liquid crystal display device according to the present invention. As shown in FIG. 11, the liquid crystal molecules are initially vertically oriented, pixel electrodes 101 and 103 arranged in a predetermined pattern are positioned on the lower substrate, and a common electrode 102 without a pattern is formed on the upper substrate. In the off-state, since the liquid crystal molecules are vertically oriented in the cell, the polarized light passing through the lower polarizer 1a does not feel a phase delay in the liquid crystal layer 4 in the cell, and the polarized light is lowered. It does not pass by the upper analyzer 1b located crossing the polarizer 1a. When a voltage is applied, an inclined electric field is formed in the cell and liquid crystal molecules lie accordingly. Therefore, the polarized light passing through the lower polarizer 1a passes through the liquid crystal layer 4 in the cell and feels a phase delay, and the polarized light passes through the upper analyzer 1b positioned crossing the lower polarizer 1a. Is done. At this time, the liquid crystal molecules located close to the lower substrate lie down a lot under the influence of a relatively strong gradient electric field, and the intensity of the gradient electric field decreases toward the upper substrate, so that the liquid crystal molecules lie down. In addition, between the electrodes, the lying direction of liquid crystal molecules is different, and thus a double domain is automatically formed. Due to the movement of the liquid crystal molecules, the liquid crystal display according to the present invention has a very improved visibility according to a viewing angle. This is because the less lying liquid crystal molecules on the upper substrate side compensate for the liquid crystal molecules on the lower substrate side.

12 is a diagram illustrating a voltage application method of a multi-domain liquid crystal display device according to the present invention. A horizontal electric field between sub-pixel electrodes was strongly formed by applying a voltage having the same size but opposite polarity to each sub-pixel electrode. Accordingly, when driving, a weak gradient electric field is formed between the lower pixel electrode and the upper common electrode, and a strong horizontal electric field is formed between the sub-pixel electrodes, and as a result, a strong gradient electric field is formed in the cell, which is a vector sum of the two electric fields.

13 is a graph showing the relationship between voltage and transmittance of a conventional VA-IPS and a liquid crystal display device according to the present invention (Voltage-Transmittance Curve), and through the graph, the multi-domain liquid crystal display device according to the present invention has a high transmittance and a relatively low It can be seen that the driving voltage is applied. In the above graph, a liquid crystal having a positive dielectric anisotropy (Δε=7.4, Δn=0.09) was inserted into the liquid crystal layer 4, and the thickness of the liquid crystal layer was formed to 5µm, and the phase delay of the liquid crystal layer was formed. It is the result of the experiment when the value is 0.45 µm.

There are two types of methods for driving two sub-pixels of a multi-domain liquid crystal display device according to the present invention depending on whether a gate line or a data line is shared. In the first case, the two sub-pixels each have a separate data line and share the gate line (1gate-2data). In the second case, the two sub-pixels share one data line and are driven as two gate lines. This is the method (2gate-1data).

Next, the liquid crystal assembly according to the present invention will be described in detail with reference to FIGS. 4A, 4B, 8, and 9. Embodiments 1 and 2 of the multi-domain liquid crystal display device according to the present invention basically have the same electrode structure and describe differences in driving methods. Example 1 describes the 1gate-2data method, and Example 2 describes the 2gate-1data method.

4A and 8, Embodiment 1 of a multi-domain liquid crystal display device according to the present invention will be described in detail.

-Example 1-

A gate line 300a and a storage electrode line 500 are formed on the lower glass insulating substrate 2a made of transparent glass or the like, and under the lower glass insulating substrate 2a, a polarizing plate 1a ) Is located. The polarization plate 1a of the lower substrate and the polarization plate 1b of the upper substrate are positioned perpendicular to each other, and they are located on both outer surfaces of the liquid crystal assembly.

The gate line 300a is connected to a switching element of each pixel electrode to transfer a gate signal, and is usually positioned perpendicular to the data lines 200a and 200b in the horizontal direction. The portion of the gate line connected to the switching element protrudes easily to be connected to the switching element and has a slightly large area.

The storage electrode line 500 is usually positioned in a horizontal direction parallel to the gate line, and each storage electrode line 500 may have a different shape and position according to a single pixel structure.

The gate line 300a and the sustain electrode line 500 are preferably made of a material having low specific resistance and high conductivity in order to reduce a delay in a transmitted signal and reduce a voltage drop due to structural characteristics. However, the gate line 300a and the storage electrode line 500 may be made of various different metals or conductors.

A gate insulating layer 3a is formed on the gate line 300a and the storage electrode line 500. The gate insulating layer 3a is formed to insulate the gate line 300a from other metallic conductors over the sustain electrode line 500.

On the gate insulating film 3a, semiconductor layers 4a and 4b made of amorphous silicon (a-Si:H) or the like are formed. The semiconductor layer is mainly located on the gate electrode of the switching element to form a semiconductor layer of a thin film transistor (TFT).

Island-like ohmic contacts 5a and 5b are formed on the semiconductor layers 4a and 4b. The island-type contact resistance member is formed on the semiconductor layer to assist the activation of the thin film transistor.

First and second data lines 200a and 200b and first and second drain electrodes, respectively, on the gate insulating film 3a and the island-type ohmic contacts 5a and 5b, respectively. 201a, 201b), first and second source electrodes are formed.

The data lines 200a and 200b are mainly positioned vertically to the gate line 300 and the storage electrode line 500 in the vertical direction and transmit a data voltage. Each data line 200a, 200b includes drain electrodes 201a, 201b and source electrodes 401a, 401b of the first and second switching elements, and their shape and position may vary depending on the shape of the switching element. .

The data lines 200a and 200b and the drain electrodes 201a and 201b are preferably made of a material having low specific resistance and high conductivity. However, the gate lines 300a and 300b and the sustain electrode line 500 may be made of various different metals or conductors.

The island-shaped resistive contact members 5a and 5b are only present between the semiconductor layers 4a and 4b below them and the source electrodes 401a and 401b and the drain electrodes 201a and 201b of the data lines 200a and 200b above them. And it serves to help the operation of the switching element by lowering the contact resistance between these electrodes and the semiconductor layers (4a, 4b).

A passivation layer 3b is formed on the data lines 200a and 200b and the drain electrodes 201a and 201b, the source electrodes 401a and 401b, and portions of the semiconductor layers 4a and 4b exposed between the electrodes. Is formed. The passivation layer 3b is made of a material having a low dielectric constant and a high degree of flatness, and protects the semiconductor layers 4a and 4b exposed between the electrodes and prevents a short circuit between the electrodes.

The first and second subpixel electrodes 101 and 103 are positioned on the passivation 3b, and they are made of transparent metal such as indium tin oxide (ITO).

A vertical alignment layer 3c capable of aligning the liquid crystal layer 4 into which liquid crystal molecules are to be inserted is coated on top of the subpixel electrodes 101 and 103 and the passivation 3b, and a vertical alignment layer is formed. (3c) is made of a material that can give an alignment force to the liquid crystal layer 4 such as PI (poly imid) or PIA (poly imid).

Hereinafter, the upper display panel of the liquid crystal assembly will be described with reference to FIGS. 3, 6, and 7.

Under the upper insulating substrate 2b made of transparent glass or the like, a polarizing plate 1b for polarization of light is located, and a light blocking member (black matrix: BM) 700 is positioned on the upper insulating substrate 2b. This leak is prevented, and the position thereof is located on the upper side of the switching element and the data lines 200a and 200b and the gate line 300a where the orientation of the liquid crystal molecules tends to be disturbed. , It is a little larger than the size of the gate line. However, the light blocking member 700 may have a different position or shape to improve visibility and performance of the liquid crystal assembly.

A color filter 700 is formed on the upper insulating substrate 2b and the light blocking member 700. The color filter 700 is located after the light blocking member 700, but is located inside the area surrounded by the light blocking member 700, so that the overlapping portions are very narrow. The color filter 700 is composed of red, green, and blue, and a color filter 700 of one color is located in one pixel, and these red, green And blue (blue) color filter 700 is arranged in sequence, but this may also be changed to improve visibility and performance.

A protective film 5 is formed on the light blocking member 600 and the color filter 700, which prevents the color filter 700 and the light blocking member 600 from being exposed and increases the flatness as a whole.

A common electrode 102 without a pattern is positioned on the passivation layer 5. The common electrode consists of a transparent electrode such as indium tin oxide (ITO), and corrects that the voltage of the + frame and-frame of the alternating voltage applied to the pixel electrode is slightly changed by other factors. Voltage is applied.

A vertical alignment layer 3c capable of aligning the liquid crystal layer 4 into which liquid crystal molecules are to be inserted is coated on the common electrode 102, and the vertical alignment layer 3c is a liquid crystal such as PI (poly imid) or PIA (poly imid). It is made of a material that can give an orientation to the layer (4).

In the liquid crystal layer 4 into which liquid crystal molecules are inserted, liquid crystals having a positive value of dielectric anisotropy (Δε=7.4, Δn=0.09) are inserted, and the thickness of the liquid crystal layer is formed to 5㎛. Therefore, the phase delay value of the liquid crystal layer is 0.45 μm. When the liquid crystal assembly is driven, an electric field is formed perpendicular to the surface inside the liquid crystal layer, and the liquid crystal molecules show motion accordingly. In more detail, when an electric field is formed inside the liquid crystal layer 4, it is not formed completely perpendicular to the surface, and the electric field and the sub speed electrode between the pixel electrodes 101, 103 and the upper common electrode 102 A strong gradient electric field with tilt is formed by the electric field formed in the liver. As a result, the liquid crystal molecules do not collide with each other and have a stable arrangement, and have a fast response speed. These are physically divided into a total of four domains by vertically and symmetrically arranging around the sustain electrode line 500 in the center of the pixel. . When a signal is transmitted from another image through the data lines 200a and 200b, the signal is moved to the drain electrodes 201a and 201b of each switching element through the data lines 200a and 200b, which are gate electrodes of the switching element. The on/off of the voltage delivered to the source electrodes 401a and 401b of each switching element is determined by (300a), and the potential difference transferred to the source electrodes 401a and 401b of each switching element is the same, Voltages having opposite polarities are directly connected to the sub-pixel electrodes 101 and 103. As a result, one pixel is divided into four domains.

The basic structure and driving method of the embodiment according to the present invention have been described above, and the operation principle will be described in detail next.

Looking at the operating principle of the embodiment according to the present invention are as follows.

When a signal is transmitted from one image through the data lines 200a and 200b, the signal is moved through the data lines 200a and 200b to the drain electrodes 201a and 201b of each switching element, which is the gate electrode of each switching element. The on/off of the voltage transmitted to the source electrodes 401a and 401b of each switching element is determined by (300a), and the potential difference transferred to the source electrodes 401a and 401b of each switching element is The same but different polarity voltage is directly connected to each of the sub-pixel electrodes 101 and 103 through the drain electrode. As a result, a signal having the same potential difference but opposite polarity is applied to each of the sub-pixel electrodes 101 and 103 from one image information, so that a horizontal electric field between the sub-pixel electrodes is strongly formed. Accordingly, when driving, a weak gradient electric field is formed between the lower pixel electrode and the upper common electrode, and a strong horizontal electric field is formed between the sub-pixel electrodes, and as a result, a strong gradient electric field is formed in the cell, which is a vector sum of the two electric fields.

Next, Embodiment 2 of the multi-domain liquid crystal display device according to the present invention will be described in detail with reference to FIGS. 4B and 9.

-Example 2-

A first gate line 300a, a second gate line 300b, and a storage electrode line 500 are formed on the lower glass insulating substrate 2a made of transparent glass or the like. The polarizing plate 1a is positioned under the lower glass insulating substrate 2a. The polarization plate 1a of the lower substrate and the polarization plate 1b of the upper substrate are positioned perpendicular to each other, and they are located on both outer surfaces of the liquid crystal assembly.

The gate lines 300a and 300b are connected to a switching element of each pixel electrode to transfer a gate signal, and are usually positioned perpendicular to the data lines 200a and 200b in the horizontal direction. The portion of the gate line connected to the switching element protrudes easily to be connected to the switching element and has a slightly large area.

The storage electrode line 500 is usually positioned in a horizontal direction parallel to the gate line, and each storage electrode line 500 may have a different shape and position according to a single pixel structure.

The gate lines 300a and 300b and the storage electrode line 500 are aluminum (Al), silver (Ag), and chromium (low resistivity and high conductivity materials) in order to reduce the delay of the transmitted signal and reduce the voltage drop due to the structural characteristics. Cr) or an alloy of the above material is preferable. However, the gate lines 300a and 300b and the sustain electrode line 500 may be made of various different metals or conductors.

A gate insulating film 3a made of silicon nitride (SiNx) or the like is formed on the gate lines 300a and 300b and the storage electrode line 500. The gate insulating film 3a is formed to insulate the gate lines 300a and 300b from other metallic conductors over the sustain electrode line 500.

On the gate insulating film 3a, semiconductor layers 4a and 4b made of amorphous silicon (a-Si:H) or the like are formed. The semiconductor layer is mainly located on the gate electrode of the switching element to form a semiconductor layer of a thin film transistor (TFT).

On the top of the semiconductor layers 4a, 4b, island-like ohmic contacts 5a, 5b formed of n-type doped amorphous silicon (n ⁺ a-Si:H) or the like are formed. The island-type contact resistance member is formed on the semiconductor layer to assist the activation of the thin film transistor.

First and second data lines 200a and 200b and first and second drain electrodes, respectively, on the gate insulating film 3a and the island-type ohmic contacts 5a and 5b, respectively. 201a, 201b), first and second source electrodes are formed.

The data lines 200a and 200b are mainly positioned vertically to the gate lines 300a and 300b and the storage electrode line 500 in the vertical direction and transmit a data voltage. Each data line 200a, 200b includes drain electrodes 201a, 201b and source electrodes 401a, 401b of the first and second switching elements, and their shape and position may vary depending on the shape of the switching element. .

The data lines 200a and 200b and the drain electrodes 201a and 201b are preferably made of materials such as aluminum (Al), silver (Ag), chromium (Cr) or alloys of the above materials having low specific resistance and high conductivity. Do. However, the gate lines 300a and 300b and the sustain electrode line 500 may be made of various different metals or conductors.

The island-shaped resistive contact members 5a and 5b are only present between the semiconductor layers 4a and 4b below them and the source electrodes 401a and 401b and the drain electrodes 201a and 201b of the data lines 200a and 200b above them. And it serves to help the operation of the switching element by lowering the contact resistance between these electrodes and the semiconductor layers (4a, 4b).

A passivation layer 3b is formed on the data lines 200a and 200b and the drain electrodes 201a and 201b, the source electrodes 401a and 401b, and portions of the semiconductor layers 4a and 4b exposed between the electrodes. Is formed. The passivation layer 3b is made of a material having a low dielectric constant and a high degree of flatness, and protects the semiconductor layers 4a and 4b exposed between the electrodes and prevents a short circuit between the electrodes.

The first and second subpixel electrodes 101 and 103 are positioned on the passivation 3b, and they are made of a transparent metal such as indium tin oxide (ITO).

A vertical alignment layer 3c capable of aligning the liquid crystal layer 4 into which liquid crystal molecules are to be inserted is coated on the pixel electrodes 101 and 103 and the passivation 3b, and the vertical alignment layer 3c ) Is made of a material that can give an alignment force to the liquid crystal layer 4 such as PI (poly imid) or PIA (poly imid).

Hereinafter, the upper display panel of the liquid crystal assembly will be described with reference to FIGS. 3, 6, and 7.

Under the upper insulating substrate 2b made of transparent glass or the like, a polarizing plate 1b for polarization of light is located, and a light blocking member (black matrix: BM) 700 is positioned on the upper insulating substrate 2b. To prevent leakage, the position is located on the top of the switching element and the data lines 200a, 200b and the gate lines 300a, 300b where the orientation of the liquid crystal molecules tends to be disturbed, the size of which is the above switching element, data line , It is a little larger than the size of the gate line. However, the light blocking member 700 may have a different position or shape to improve visibility and performance of the liquid crystal assembly.

A color filter 700 is formed on the upper insulating substrate 2b and the light blocking member 700. The color filter 700 is located next to the light blocking member 700, but is located inside the area surrounded by the light blocking member 700, so the overlapping portion is very narrow. The color filter 700 is composed of red, green, and blue, and a color filter 700 of one color is located in one pixel, and these red, green And blue (blue) color filter 700 is arranged in sequence, but this may also be changed to improve visibility and performance.

A protective film 5 is formed on the light blocking member 600 and the color filter 700, which prevents the color filter 700 and the light blocking member 600 from being exposed and increases the flatness as a whole.

A common electrode 102 without a pattern is positioned on the passivation layer 5. The common electrode is made of a transparent electrode such as indium tin oxide (ITO) and corrects that the voltage of the + frame and-frame of the AC voltage applied to the pixel electrode is slightly changed by other factors. The voltage to do is applied.

On the common electrode 102, a vertical alignment layer 3c capable of aligning the liquid crystal layer 4 into which liquid crystal molecules are to be inserted is coated, and the vertical alignment layer 3c is formed of polyimid (PI) or polyimid (PIA). It is made of a material that can give an alignment force to the liquid crystal layer 4.

In the liquid crystal layer 4 into which liquid crystal molecules are inserted, a liquid crystal having a positive value of dielectric anisotropy (Δε=7.4, Δn=0.09) is inserted, and the thickness of the liquid crystal layer is formed to 5㎛. Therefore, the phase delay value of the liquid crystal layer is 0.45 µm. When the liquid crystal assembly is driven, an electric field is formed perpendicular to the surface inside the liquid crystal layer, and the liquid crystal molecules show motion accordingly. In more detail, when an electric field is formed inside the liquid crystal layer 4, it is not formed completely perpendicular to the surface, but is formed between the electric field between the pixel electrodes 101, 103 and the upper common electrode 102 and the sub-speed electrode. A strong inclined electric field with a tilt is formed by the electric field. As a result, the liquid crystal molecules do not collide with each other and have a stable arrangement, and have a fast response speed. These are physically divided into four domains by vertically and symmetrically arranging around the sustain electrode line 500 in the center of the pixel. . When a signal is transmitted from another image through the data lines 200a and 200b, the signal is moved through the data lines 200a and 200b to the drain electrodes 201a and 201b of each switching element, which is the gate of each switching element. The on/off of the voltage transmitted to the source electrodes 401a and 401b of each switching element is determined by the electrodes 300a and 300b, and the potential difference transmitted to the source electrodes 401a and 401b of each switching element is the same but the polarity is the same. The opposite voltage is directly connected to each sub-pixel electrode (101, 103). As a result, one pixel is divided into four domains.

The basic structure and driving method of the embodiment according to the present invention has been described above. Although the above embodiments have two sub-pixel electrodes and two TFFs for one pixel, they do not limit that additional sub-pixel electrodes and TFTs are provided as needed.

Hereinafter, the operation principle of the embodiment according to the present invention will be described in detail.

When a signal is transmitted from one image through the data lines 200a and 200b, the signal is moved through the data lines 200a and 200b to the drain electrodes 201a and 201b of each switching element, which is the gate electrode of each switching element. The on/off of the voltage transmitted to the source electrodes 401a, 401b of each switching element is determined by (300a, 300b), and the potential difference transmitted to the source electrodes 401a, 401b of each switching element is the same but the polarity is the same. The other voltage is directly connected to each of the sub-pixel electrodes 101 and 103 through the drain electrode. As a result, a signal having the same potential difference but opposite polarity is applied to each of the sub-pixel electrodes 101 and 103 from one image information, so that a horizontal electric field between the sub-pixel electrodes is strongly formed. As a result, when driving, a weak gradient electric field is formed between the lower pixel electrode and the upper common electrode, and a strong horizontal electric field is formed between the sub-pixel electrodes, and as a result, a strong gradient electric field that is a vector sum of the two electric fields is formed in the cell.

A first gate line 300a and a second gate line 300b are formed on the lower glass insulating substrate 2a made of transparent glass or the like, and under the lower glass insulating substrate 2a. The polarizing plate 1a is located. The polarizing plate 1a of the lower substrate and the polarizing plate 1b of the upper substrate are positioned perpendicular to each other, and they are located on both outer surfaces of the liquid crystal assembly.

The gate lines 300a and 300b are connected to a switching element of each pixel electrode to transfer a gate signal, and are usually positioned perpendicular to the data lines 200a and 200b in the horizontal direction. The gate electrode portion of the gate line connected to the switching element protrudes easily to be connected to the switching element, and has a slightly larger area.

1 is a block diagram of a 1gate-2data method of a multi-domain liquid crystal display device according to an embodiment of the present invention,

2 is a block diagram of a 2gate-1data method of a multi-domain liquid crystal display device according to an embodiment of the present invention,

3A is an equivalent circuit diagram of one pixel for a 1gate-2data method of a multi-domain liquid crystal display device according to an embodiment of the present invention,

3B is an equivalent circuit diagram of one pixel for a 2gate-1data method of a multi-domain liquid crystal display device according to an embodiment of the present invention,

4A is a layout view of a liquid crystal panel assembly for a 1gate-2data method of a liquid crystal display device according to an embodiment of the present invention,

4B is a layout view of a liquid crystal panel assembly for a 2gate-1data method of a liquid crystal display device according to an embodiment of the present invention,

5A is a layout view of a first subpixel electrode of a lower panel for a 1gate-2data method of a liquid crystal display device according to an embodiment of the present invention;

5B is a layout view of a first subpixel electrode of a lower panel for a 2gate-1data method of a liquid crystal display according to an embodiment of the present invention,

6A is a layout view of a second sub-pixel electrode of a lower display panel for a 1gate-2data method of a liquid crystal display device according to an embodiment of the present invention;

6B is a layout view of a second sub-pixel electrode of a lower display panel for a 2gate-1data method of a liquid crystal display device according to an embodiment of the present invention,

7 is a layout view of an upper panel of a liquid crystal display according to an exemplary embodiment of the present invention,

8 is a cross-sectional view of the liquid crystal panel assembly of FIG. 4A taken along lines III to III',

9 is a cross-sectional view of the liquid crystal panel assembly of FIG. 4B taken along line IV to IV',

10 is a cross-sectional view of the liquid crystal panel assembly of FIG. 4B taken along line VV to V',

11 is a view showing the arrangement of liquid crystal molecules before and after the voltage is applied to the multi-domain liquid crystal display according to the present invention,

12 is a diagram illustrating a voltage application method of a multi-domain liquid crystal display device according to the present invention,

13 is a graph showing the relationship between the voltage and transmittance of the multi-domain liquid crystal display according to the present invention.
* Names of major parts used in drawings
1a,1b: Polarizing plate 2a,2b: Glass insulating substrate
3a: gate insulating film 3b: passivation layer
3c, 3d: vertical alignment film 4: liquid crystal layer
4a, 4b: activated semiconductor layer 5: passivation layer
5a, 5b: resistive contact member 101: first subpixel electrode
102: common electrode located on the upper substrate
103: second sub-pixel electrode 200a: first data line
200b: second data line 201a: drain of the switching element
300a: first gate line 300b: second gate line
301a,301b: gate of the switching element 401a,401b: source of the switching element
600: color filter 700: light blocking member (back matrix: BM)

Claims (9)

In the liquid crystal display device, A liquid crystal layer initially vertically oriented and having a positive dielectric anisotropy, A plurality of pixel electrodes positioned under the liquid crystal layer and arranged in a predetermined pattern, A common electrode located on the liquid crystal layer and having no pattern, And a switching element connected to the pixel electrode and the common electrode, The pixel electrode and the switching element are provided with a plurality of one pixel, a liquid crystal display device. According to claim 1, A liquid crystal display device, characterized in that voltages having opposite polarities are alternately applied to the plurality of pixel electrodes. According to claim 2, A liquid crystal display device, characterized in that a voltage having the same magnitude is applied to the plurality of pixel electrodes. According to claim 2, A liquid crystal display device characterized in that a voltage having a different size is applied to the plurality of pixel electrodes. According to claim 1, The switching element is a thin film transistor, In a plurality of thin film transistors provided for one pixel, a data line is connected to the pixel electrode and shares a gate line. According to claim 1, The switching element is a thin film transistor, A plurality of thin film transistors provided for one pixel, wherein a gate line is connected to the pixel electrode and shares a data line. According to claim 1, The plurality of pixel electrodes are different in size or shape, characterized in that the liquid crystal display device. According to claim 1, A vertical alignment layer vertically aligning the liquid crystal layer is provided on the liquid crystal layer, The common electrode is positioned on the vertical alignment layer, A liquid crystal display device further comprising a dielectric between the vertical alignment layer and the common electrode. In the liquid crystal display device, A liquid crystal layer initially vertically oriented and having a positive dielectric anisotropy, A lower alignment layer positioned under the liquid crystal layer and vertically aligning the liquid crystal layer; An upper alignment layer positioned on the liquid crystal layer and vertically aligning the liquid crystal layer; A plurality of pixel electrodes positioned under the lower alignment layer and arranged in a predetermined pattern, A common electrode located on the liquid crystal layer and having no pattern, A switching element connected to the pixel electrode and the common electrode, A lower polarizing plate positioned under the pixel electrode; The upper polarizing plate is disposed on the common electrode and has a transmission axis perpendicular to the transmission axis of the lower polarizing plate. A plurality of the pixel electrode and the switching element are provided for one pixel, A liquid crystal display device, characterized in that voltages having opposite polarities are alternately applied to the plurality of pixel electrodes.

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