WO2006126494A1

WO2006126494A1 - Liquid crystal display

Info

Publication number: WO2006126494A1
Application number: PCT/JP2006/310161
Authority: WO
Inventors: Kengo Kanii
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2005-05-24
Filing date: 2006-05-22
Publication date: 2006-11-30
Also published as: TWI336414B

Abstract

Disclosed is a liquid crystal display having good display characteristics which is used in a display part of an electronic device. Specifically disclosed is a liquid crystal display comprising a pixel electrode (16) formed on a TFT substrate (2) and electrically connected with a TFT (20) which is also formed on the TFT substrate (2), a pixel electrode (17) electrically insulated from the TFT (20), an alignment film (50) formed on a surface of the TFT substrate (2) facing a counter substrate (4), and a polymer layer (52) for preventing image burn-in which is formed by thermally or optically polymerizing a monomer contained in a liquid crystal layer (6) near the interface with the TFT substrate (2) so as to cover the alignment film (50) on the pixel electrode (17).

Description

Specification

Liquid crystal display

Technical field

The present invention relates to a liquid crystal display device used for a display unit or the like of an electronic device.

Background art

In recent years, liquid crystal display devices have come to be used as television receivers, personal computer monitor devices, and the like. In these applications, a wide viewing angle that allows the display screen to be viewed from all directions is required. As a liquid crystal display device capable of obtaining a wide viewing angle, an MVA (Multi-domain Vertical Alignment) type liquid crystal display device is known. The MVA liquid crystal display device includes a liquid crystal having negative dielectric anisotropy sealed between a pair of substrates and a vertical alignment film that aligns liquid crystal molecules almost perpendicularly to the substrate surface. An MVA-type liquid crystal display device can provide a wider viewing angle than a conventional TN liquid crystal display device by providing a plurality of regions with different orientation directions of liquid crystal molecules in one pixel. In addition, the MVA liquid crystal display device can control the alignment orientation of liquid crystal molecules when a voltage is applied without subjecting the vertical alignment film to rubbing treatment.

By the way, in the vertical alignment type liquid crystal display device in which liquid crystal molecules are aligned perpendicularly to the substrate as in the MVA method, light switching is performed mainly utilizing the birefringence of the liquid crystal. In general, in a vertically aligned liquid crystal display device, the phase difference caused by birefringence differs between light traveling in the normal direction of the display screen and light traveling in an oblique direction. However, in the diagonal direction of the screen, the gradation luminance characteristic (γ characteristic) deviates from the set value for all gradations. Therefore, the transmittance characteristics (ΤV characteristics) with respect to the voltage applied to the liquid crystal are different between the normal direction and the diagonal direction of the display screen, so even if the ΤV characteristic in the screen normal direction is optimally adjusted, the diagonal direction From the viewpoint of Τ, there is a phenomenon power S that the V characteristic is distorted and the color of the screen changes whitish. This phenomenon is called “Wash Out”.

[0004] As a means of improving white-out, sub-pixel A having a pixel electrode (direct connection portion) in which a pixel region is electrically connected to a switching element (for example, TFT: thin film transistor), and TFT V subdivided into a sub-pixel B in which a pixel electrode (capacitive coupling part) is formed that forms a capacitance between the TFT source electrode and the control capacitor electrode that is equipotentially insulated. The so-called capacitive coupling HT method (halftone grayscale method) has been proposed. In a liquid crystal display device using the capacitive coupling HT method, by providing a direct coupling portion and a capacitive coupling portion in the pixel electrode, the pixel has different γ characteristics, so that the phase difference due to birefringence in the oblique direction is different from the front. It becomes possible to suppress the deviation, and it is possible to suppress white mist.

However, the conventional liquid crystal display device using the capacitive coupling method has a problem that although the viewing angle characteristics are improved, seizure occurs so that good display characteristics cannot be obtained. . FIG. 9 is a diagram for explaining image sticking that occurs in a conventional liquid crystal display device using the capacitive coupling method. Figure 9 (a) shows the black and white checker pattern displayed on the screen during the seizure test. In the burn-in test, immediately after the checker pattern shown in Fig. 9 (a) is continuously displayed for a certain period of time (for example, 48 hours), a halftone of the same gradation (32Z64 gradation) is displayed on the entire screen, and the checker pattern is displayed. Inspect whether the pattern is visually recognized. When the checker pattern is seen, measure the screen brightness along one direction of the checker pattern and calculate the burn-in rate. Here, bZa is defined as the burn-in rate when the luminance of the low luminance region of the checker pattern to be viewed is a and the luminance of the high luminance region is a + b (> a).

[0006] Fig. 9 (b) shows a screen displaying halftones on a liquid crystal display device that does not use the capacitively coupled HT method, and Fig. 9 (c) shows a conventional liquid crystal display device that uses the capacitively coupled HT method. Shows a screen displaying halftones. As shown in Fig. 9 (b), in the liquid crystal display device that does not use the capacitively coupled HT method, the checker pattern was almost invisible during halftone display. When the luminance was measured along the YY 'line in Fig. 9 (b), the luminance had a distribution as shown by the line c in Fig. 9 (d). The seizure rate was only 0-5%. On the other hand, in the liquid crystal display using the capacitively coupled HT method, a checker pattern as shown in Fig. 9 (c) was visually recognized. When the luminance was measured along the YY 'line in Fig. 9 (c), the luminance had a distribution as shown by the line d in Fig. 9 (d). The seizure rate was 10% or more. In this way, when the capacitively coupled HT method is used, liquid crystal display devices hardly cause seizure, whereas liquid crystal display devices using the capacitively coupled HT method exhibit relatively high density and seizure. appear.

[0007] Results of evaluation and analysis of characteristic distribution in pixels of liquid crystal display device where burn-in occurred It was found that burn-in occurred in subpixel B where the pixel electrode in the electrically floating state was formed. The pixel electrode of the sub-pixel B is connected to the control capacitor electrode through a silicon nitride film (SiN film) having a very high electric resistance, and is connected to the common electrode through a liquid crystal layer having a very high electric resistance. For this reason, the electric charge charged in the pixel electrode of the sub-pixel B is not easily discharged. On the other hand, a predetermined potential is written to the pixel electrode of the subpixel A electrically connected to the TFT source electrode for each frame, and the pixel electrode of the subpixel A is extremely different from the SiN film or the liquid crystal layer. Low electrical resistance! ヽ It is connected to the drain bus line through the TFT operating semiconductor layer. For this reason, the charge charged in the pixel electrode will not be discharged.

[0008] Patent Document 1: Japanese Patent No. 3076938

Patent Document 2: Japanese Patent Laid-Open No. 2003-149647

Disclosure of the invention

Problems to be solved by the invention

[0009] As described above, the conventional liquid crystal display device using the capacitively coupled HT method has a problem that although the viewing angle characteristics are improved, seizure occurs, and thus good display characteristics cannot be obtained. .

An object of the present invention is to provide a liquid crystal display device capable of obtaining good display quality. Means for Solving the Problems

[0011] The object is to provide a pair of opposed substrates, a liquid crystal layer sandwiched between the pair of substrates, a switching element formed on one of the substrates and formed on the one substrate, and A pixel electrode having a directly coupled portion electrically connected, a capacitive coupling portion electrically insulated from the switching element, and a static coupling between the capacitive coupling portion and electrically connected to the switching element. A control capacitor electrode for forming a capacitance, an alignment film formed on the opposing surfaces of the pair of substrates, and a polymerizable component contained in the liquid crystal layer are polymerized by heat or light to be near the interface with the substrate. And a polymer layer for preventing seizure that covers the entire alignment film on the capacitive coupling portion. [0012] The liquid crystal display device of the present invention is characterized in that the alignment film is completely covered with the polymer layer.

[0013] In the liquid crystal display device of the present invention, the polymer layer has a thickness of 130 Am or more.

In the liquid crystal display device of the present invention, the concentration of the polymerizable component is 0.2% or more.

The invention's effect

[0015] According to the present invention, it is possible to realize a liquid crystal display device capable of obtaining good display quality.

BEST MODE FOR CARRYING OUT THE INVENTION

A liquid crystal display device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of the liquid crystal display device according to the present embodiment. As shown in FIG. 1, a liquid crystal display device includes a gate bus line and a drain bus line that are formed to cross each other with an insulating film interposed therebetween, and a thin film transistor (TFT) and a pixel electrode that are formed for each pixel. It has a TFT substrate 2 provided. In addition, the liquid crystal display device includes a counter substrate 4 on which a color filter (CF) and a common electrode are formed and disposed opposite to the TFT substrate 2. Both the substrates 2 and 4 are bonded together via a sealing material formed on the outer peripheral portion of their facing surfaces. Between the substrates 2 and 4, vertically aligned liquid crystal having negative dielectric anisotropy is sealed, and a liquid crystal layer 6 (not shown in FIG. 1) is formed.

[0017] On the TFT substrate 2, a gate nos drive circuit 80 on which a driver IC for driving a plurality of gate bus lines is mounted, and a drain bus line drive circuit 82 on which a driver IC for driving a plurality of drain nos lines is mounted. And are connected. These drive circuits 80 and 82 are configured to output a scanning signal and a data signal to a predetermined gate bus line or drain bus line based on a predetermined signal output from the control circuit 84. A polarizing plate 87 is disposed on the surface of the TFT substrate 2 opposite to the TFT element forming surface, and a polarizing plate 86 is crossed with respect to the polarizing plate 87 on the surface of the counter substrate 4 opposite to the common electrode forming surface. It is placed in the col. A backlight unit 88 is disposed on the surface of the polarizing plate 87 opposite to the TFT substrate 2.

FIG. 2 shows a configuration of one pixel of the liquid crystal display device according to the present embodiment, and FIG. The cross-sectional structure of the liquid crystal display device cut | disconnected by A line is shown. As shown in FIG. 2 and FIG. 3, the TFT substrate 2 of the liquid crystal display device includes a plurality of gate bus lines 12 formed on a transparent insulating substrate (for example, a glass substrate) 10 and a gate bus via an insulating film 30. And a plurality of drain bus lines 14 formed so as to intersect the line 12. A storage capacitor bus line 18 extending in parallel with the gate bus line 12 is formed across the pixel region surrounded by the gate bus line 12 and the drain bus line 14. In the vicinity of the intersection position of the gate bus line 12 and the drain bus line 14, a TFT 20 is formed as a switching element arranged for each pixel. The drain electrode 21 of the TFT 20 is electrically connected to the drain bus line 14. A part of the gate bus line 12 functions as a gate electrode of the TFT 20. A protective film 31 is formed on the entire surface of the substrate on the drain bus line 14 and the TFT 20. On the front surface of the substrate on the protective film 31, an alignment film 50 for aligning liquid crystal molecules almost perpendicularly to the substrate surface is formed. At the interface between the alignment film 50 and the liquid crystal layer 6, a polymer layer 52 that controls the alignment direction of the liquid crystal molecules is formed.

[0019] Each pixel region on the protective film 31 has a pixel electrode 16 made of a transparent conductive film such as ITO, for example.

A (directly connected portion) and a pixel electrode 17 (capacitive coupling portion) are formed. As shown in FIG. 2, each pixel region of the liquid crystal display device according to the present embodiment includes a sub-pixel A arranged in the center and two sub-pixels B arranged above and below the sub-pixel A in the figure. And have. The ratio of the area of subpixel A and the area of subpixel B (the sum of the areas of two subpixels B) in one pixel is, for example, 5: 5. The first pixel electrode 16 is formed in the subpixel A, and the second pixel electrode 17 in which the pixel electrode 16 force is separated is formed in the subpixel B, for example, in the same layer as the pixel electrode 16 in the same layer. . In the pixel region, a control capacitor electrode 26 that is electrically connected to the source electrode 22 and the storage capacitor electrode 19 and extends in the vertical direction in the figure is formed. The control capacitor electrode 26 is disposed to face at least a part of the pixel electrode 17 with an insulating film interposed therebetween.

The pixel electrode 16 formed in the sub-pixel A is arranged so as to overlap the storage capacitor bus line 18 and the storage capacitor electrode 19 and extends substantially parallel to the gate bus line 12. The drain electrode 14 And a linear electrode 16b extending substantially in parallel. In addition, the pixel electrode 16 is formed between a plurality of linear electrodes 16c that branch obliquely from the linear electrode 16a or 16b and extend in stripes in four orthogonal directions within the subpixel A, and adjacent linear electrodes 16c. And a fine slit 16d. The width 1 of the linear electrode 16c is, for example, 6 m, and the width s of the fine slit 16d is, for example, 3. The pixel electrode 16 is electrically connected to the storage capacitor electrode 19 and the source electrode 22 through the contact hole 25.

The pixel electrodes 17 respectively formed on the two subpixels B are arranged so as to overlap the control capacitance electrode 26 via the protective film 31 and extend linearly parallel to the drain bus line 14; A plurality of linear electrodes 17b extending obliquely branched from the linear electrodes 17a and fine slits 17c formed between the adjacent linear electrodes 17b are provided. The widths of the linear electrode 17b and the fine slit 17c are substantially the same as the widths of the linear electrode 16c and the fine slit 16d.

On the other hand, the counter substrate 4 has a CF resin layer 40 formed on the glass substrate 11. Each pixel has a CF resin layer 40 of one of red, green, and blue. A common electrode 41 made of a transparent conductive film is formed on the entire surface of the substrate on the CF resin layer 40. On the entire surface of the common electrode 41, an alignment film 51 for aligning the liquid crystal molecules 8 substantially perpendicular to the substrate surface is formed. A polymer layer 53 is formed at the interface between the alignment film 51 and the liquid crystal layer 6 in the same manner as the polymer layer 52 on the TFT substrate 2 side. The polymer layers 52 and 53 are formed, for example, by polymerizing a polymerizable component such as a monomer contained in the liquid crystal from light or heat in a state where a predetermined voltage is applied to the liquid crystal layer 6.

FIG. 4 shows an equivalent circuit of one pixel of the liquid crystal display device according to this example. As shown in FIG. 4, the source electrode 22 (S) of the TFT 20 is electrically connected to the pixel electrode 16, the storage capacitor electrode 19, and the control capacitor electrode 26. A first liquid crystal capacitor Clcl is formed by the pixel electrode 16, the common electrode 41 on the opposite substrate 4 side facing the pixel electrode 16, and the liquid crystal layer 6 sandwiched between the pixel electrode 16 and the common electrode 41. Yes. The storage capacitor Cs is composed of the storage capacitor electrode 19, the storage capacitor bus line 18 facing the storage capacitor electrode 19, and the insulating film (insulating film 30) sandwiched between the storage capacitor electrode 19 and the storage capacitor nos line 18. Formed. The control capacitor Cc (control capacitor portion) is composed of the control capacitor electrode 26, the pixel electrode 17 facing the control capacitor electrode 26, and the insulating film (protective film 31) sandwiched between the control capacitor electrode 26 and the pixel electrode 17. ) Is formed. Further, the second liquid crystal capacitor Clc2 is formed by the pixel electrode 17, the common electrode 41 on the counter substrate 4 side facing the pixel electrode 17, and the liquid crystal layer 6 sandwiched between the pixel electrode 17 and the common electrode 41. Has been. In this example, it is shared with the storage capacitor bus line 18. The same potential is applied to the through electrode 41.

Thus, in the pixel of the liquid crystal display device according to the present embodiment, the second liquid crystal capacitor Clc2 and the control capacitor Cc are connected in series, and these, the first liquid crystal capacitor Clcl, and the storage capacitor Cs. Each has a circuit configuration connected in parallel. When the TFT 20 is turned on, the potential applied to the drain bus line 14 is applied to the pixel electrode 16, the storage capacitor electrode 19 and the control capacitor electrode 26, while the storage capacitor bus line 18 and the common electrode 41 have a common potential. Applied. As a result, the pixel electrode 17 is maintained at a potential lower than the potential applied to the pixel electrode 16 by a predetermined amount. If the voltage applied to the liquid crystal layer 6 of the subpixel A is Vpxl, the voltage Vpx2 applied to the liquid crystal layer 6 of the subpixel B is

Vpx2 = (Cc / (Clc2 + Cc)) XVpxl

It becomes. Here, 0 (CcZ (Clc2 + Cc)) is 1. Therefore, when Vpxl = Vpx2 = 0, the voltage Vpx2 is smaller than the voltage Vpxl by a force / J (I Vpx2 | <|

Thus, in the liquid crystal display device according to the present embodiment, the voltage Vpxl applied to the liquid crystal layer 6 of the subpixel A and the voltage Vpx2 applied to the liquid crystal layer 6 of the subpixel B are included in one pixel. You can make them different from each other. When the liquid crystal display device is driven, different voltages are applied to the liquid crystal layers 6 of the sub-pixels A and B, so that the distortion of the TV characteristics in the oblique direction is dispersed within one pixel. . Therefore, a phenomenon that the image color becomes whitish when viewed from an oblique direction (white-brown) can be suppressed, and a wide viewing angle liquid crystal display device with improved viewing angle characteristics can be obtained. .

In the liquid crystal display device according to the present embodiment, polymer layer 52 and polymer layer 53 are formed on alignment film 50 and alignment film 51. By the polymer layer 52 and the polymer layer 53, the orientation direction of liquid crystal molecules is reliably controlled in a direction parallel to the fine slit 16d and the fine slit 17c.

Furthermore, in the liquid crystal display device according to the present embodiment, as shown in FIG. 3, the entire upper part of the pixel electrode 17 is covered with the polymer layer 52 via the alignment film 50. Further, the entire upper part of the alignment film 50 is similarly covered with the polymer layer 52. The entire surface of the pixel electrode 17 and the alignment film 50, which are capacitive coupling portions, is completely covered with a polymer layer 52 having a predetermined thickness to prevent charge charging in the capacitive coupling portion and reduce image sticking. Can do. Ma The polymer layer 52 having a predetermined thickness can be formed by setting the concentration of the monomer contained in the liquid crystal to a certain level or more.

Hereinafter, the liquid crystal display device according to the present embodiment will be described more specifically with reference to examples.

[0028] (Example 1)

First, Example 1 of the present embodiment will be described. Two types of liquid crystal, an n-type liquid crystal containing a monomer (polymerizable component) that can be polymerized by UV light (MJ011412 manufactured by Merck) and an n-type liquid crystal containing a monomer (MJ011412 manufactured by Merck) Prepared. Three types of materials for vertical alignment films (polyimide or polyamic acid) PI1 to PI3 with different electrical characteristics were prepared.

[0029] Next, the 15-inch TFT substrate 2 and the counter substrate 4 as shown in FIGS. 2 and 3 were produced for 6 panels each. On the two substrates 2 and 4, the above three kinds of alignment film materials PI1 to PI3 were printed for two panels each. Both substrates 2 and 4 were heated at 200 ° C. for 10 minutes to fully cure the alignment film material, and alignment films 50 and 51 were formed. As a result, two sets of three types of substrates 2 and 4 were produced.

Next, both the substrates 2 and 4 were cleaned, and a sealing material was applied to the entire outer periphery of the TFT substrate 2 without any breaks. Subsequently, two types of liquid crystal were dropped into the regions surrounded by the sealing material of the three types of TFT substrate 2 respectively. Next, the TFT substrate 2 and the counter substrate 4 are bonded together in a vacuum and returned to atmospheric pressure to fill the liquid crystal between the substrates 2 and 4 to form the liquid crystal layer 6, and then heat treatment is performed to seal the sealing material. Cured.

Next, an alternating voltage of 17 V was applied to the liquid crystal layer 6 between each pixel electrode 16 and the common electrode 41. At the same time, an AC voltage of less than 17 V was applied to the liquid crystal layer 6 between each pixel electrode 17 and the common electrode 41. It was irradiated with UV light irradiation energy density LOOOmjZcm ² to the liquid crystal layer 6 in this state. As a result, the monomer contained in the liquid crystal was polymerized to form polymer layers 52 and 53 at the interfaces between the liquid crystal layer 6 and the alignment films 50 and 51, respectively. After the polymer layers 52 and 53 were formed, polarizing plates 86 and 87 were attached to the outer sides of the substrates 2 and 4 in a cross-coll. Through the above steps, six types of liquid crystal display panels were produced by combining three types of liquid crystals and two types of alignment film materials. [0032] After preparing six types of liquid crystal display panels, a rectangular black and white checker pattern of about 2cm x about 5cm was continuously displayed on each liquid crystal display panel at room temperature for 48 hours. Displays halftone (32Z64 gradation) and displays black for each LCD panel. Brightness of low brightness area, which is the halftone display area, and high brightness area, which is the halftone display area from white display The brightness was measured, and the burn-in rate was determined for each of the measured brightness power liquid crystal display panels.

FIG. 5 is a graph showing the burn-in rate of six types of liquid crystal display panels. The horizontal direction of the graph represents the type of alignment film, and the vertical axis represents the burn-in rate (unit:%) of the liquid crystal display panel. In Fig. 5, the types of liquid crystal display panels are divided into the alignment film material types PI1 to PI3, and then according to the presence or absence of liquid crystal monomers. As shown in FIG. 5, each of the alignment films having different electrical characteristics has a burn-in rate of the liquid crystal display panel in which the monomer is polymerized and does not contain the monomer! It is lower than the burn-in rate of the liquid crystal display panel. As a result, seizure is improved.

[0034] Fig. 6 is an exploded view of the liquid crystal display panel, and the alignment film 50 and its periphery are

It is the figure observed using the Electron Microscope (scanning electron microscope). FIG. 6 (a) is a diagram observing the alignment film 50 of the liquid crystal display panel in which the monomer is polymerized and its peripheral portion, and FIG. 6 (b) is an alignment film 50 of the liquid crystal display device that does not contain the monomer and It is the figure which observed the peripheral part. As shown in FIG. 6, the liquid crystal display panel obtained by polymerizing the monomer does not contain the monomer, and the liquid crystal display panel is formed with the polymer layer 52, and the pixel electrode 17 and the alignment film which are capacitive coupling portions. It was confirmed that it covered the entire surface of 50. Further, it has been found that the film thickness of the polymer layer 52 is 130 Am or more, and that the film thickness is 130 Am or more, the formation of the polymer layer 52 improves the image sticking of the liquid crystal display panel.

[0035] (Example 2)

In Example 2 of the present embodiment, four types of n-type liquid crystals (MJ011412 manufactured by Merck) having monomer concentrations of 0.05%, 0.1%, 0.2%, and 0.3% were prepared. . In addition, nine sets of 15-inch TFT substrate 2 and counter substrate 4 as shown in FIGS. 2 and 3 were produced.

Next, both the substrates 2 and 4 were cleaned, and a sealing material was applied to the entire outer periphery of the TFT substrate 2 without any breaks. Next, the liquid crystal containing four types of monomers is surrounded by the sealing material of TFT substrate 2. Each was dropped in the area. Next, the TFT substrate 2 and the counter substrate 4 are bonded together in a vacuum and returned to atmospheric pressure to fill the liquid crystal between the substrates 2 and 4 to form the liquid crystal layer 6 and then heat-treat and seal The material was cured.

Next, an alternating voltage of 17 V was applied to the liquid crystal layer 6 between each pixel electrode 16 and the common electrode 41. At the same time, an AC voltage of less than 17 V was applied to the liquid crystal layer 6 between each pixel electrode 17 and the common electrode 41. It was irradiated with UV light irradiation energy density LOOOmjZcm ² to the liquid crystal layer 6 in this state. As a result, the monomer contained in the liquid crystal was polymerized to form polymer layers 52 and 53 at the interfaces between the liquid crystal layer 6 and the alignment films 50 and 51, respectively. After the polymer layers 52 and 53 were formed, polarizing plates 86 and 87 were attached to the outer sides of the substrates 2 and 4 in a cross-coll. Through the above process, nine liquid crystal display panels were produced, two for each liquid crystal with four monomer concentrations (however, only three for liquid crystal display panels with a monomer concentration of 0.2%).

In this example, an n-type liquid crystal (MJ011412 manufactured by Merck Co., Ltd.) that contains a monomer was prepared. Furthermore, a 15-inch TFT substrate 2 that does not use the capacitively coupled HT method and a counter substrate 4 were produced. Figure 7 shows the configuration of one pixel in a liquid crystal display device that does not use the capacitively coupled HT method. In the liquid crystal display device shown in FIG. 7, components having the same functions and operations as those of the liquid crystal display device shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in FIG. 7, the pixel electrode 16 formed in the pixel is electrically directly connected to the source electrode 22 of the TFT 20 via the contact hole 24. Further, the pixel electrode 17 which is a capacitive coupling portion as shown in FIG. 2 is formed.

[0039] Both substrates 2 and 4 without using the capacitive coupling HT method were cleaned, and a sealing material was applied to the entire outer periphery of the TFT substrate 2 without any gaps. Subsequently, the monomer was contained! /,!, And the liquid crystal was dropped into the area surrounded by the sealing material of the TFT substrate 2. Next, the TFT substrate 2 and the counter substrate 4 are bonded together in a vacuum, and the liquid crystal is filled between the substrates 2 and 4 by returning to atmospheric pressure to form a liquid crystal layer 6, and heat treatment is performed to seal the sealing material. Cured. Polarizers 86 and 87 were attached to the outside of the substrates 2 and 4 in a cross-coll. Through the above process, one liquid crystal display panel was produced.

[0040] Nine liquid crystal display panels using the liquid crystal containing the capacitive coupling HT method and the monomer, and one sheet using the liquid crystal without using the capacitive coupling HT method and containing the monomer. After making the LCD panel, about 2cm X about 5cm Immediately after displaying the rectangular black and white checker pattern at room temperature for 48 hours, halftones (32Z64 gradations) with the same gradation were displayed on the entire screen, and halftones were displayed from black to each LCD panel. The brightness of the low brightness area, which is the area, and the brightness of the high brightness area, which is the halftone display area, were measured from the white display, and the burn-in rate was determined for each liquid crystal display panel based on the measured brightness.

FIG. 8 is a graph showing the image sticking rate of nine liquid crystal display panels in which monomers are polymerized. The horizontal axis of the graph represents the liquid crystal monomer concentration (unit:%), and the vertical axis represents the image sticking ratio (%) of the liquid crystal display panel. The diamond points in Fig. 8 indicate the burn-in rate of each liquid crystal display panel. The dotted line in Fig. 8 shows the burn-in rate (approximately 4.2%) of a liquid crystal display panel using liquid crystal without using the capacitively coupled HT method and containing no monomer.

[0042] In the liquid crystal display panel using the capacitive coupling HT method and using a liquid crystal containing a monomer, the image sticking ratio of the liquid crystal display panel decreases as the monomer concentration increases. A liquid crystal display panel with a monomer concentration of 0.05% or 0.1% has a seizure rate of 6% or more, does not use the capacitively coupled HT method, and the liquid crystal contains a monomer. With a liquid crystal display panel with a monomer concentration of 0.2% or 0.3%, the image sticking rate is less than that, and it does not use the capacitively coupled HT method and contains a monomer. Image sticking is improved compared to liquid crystal display panels using liquid crystals. From the above, it was found that image sticking of the liquid crystal display device was improved by using a liquid crystal having a monomer concentration of 0.2% or more.

[0043] The present invention is not limited to the above-described embodiment, and various modifications can be made.

For example, although the transmissive liquid crystal display device has been described as an example in the above embodiment, the present invention is not limited to this and can be applied to other liquid crystal display devices such as a reflective type and a transflective type.

In the above embodiment, the liquid crystal display device in which the CF resin layer 40 is formed on the counter substrate 4 is taken as an example. However, the present invention is not limited to this, and the CF substrate on the TFT substrate 2 is used. The present invention can also be applied to a so-called CF-on-TFT liquid crystal display device in which an oil layer is formed.

Brief Description of Drawings

FIG. 1 is a diagram showing a schematic configuration of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of one pixel of a liquid crystal display device according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a configuration of a liquid crystal display device according to an embodiment of the present invention. FIG. 4 is a diagram showing an equivalent circuit of one pixel of the liquid crystal display device according to one embodiment of the present invention.

FIG. 5 is a graph showing the burn-in rate of each liquid crystal display panel of the liquid crystal display device according to Example 1 of one embodiment of the present invention.

FIG. 6 is an enlarged view showing a part of a liquid crystal display panel.

FIG. 7 is a diagram showing a configuration of one pixel of a liquid crystal display device according to Example 2 of one embodiment of the present invention.

FIG. 8 is a graph showing the burn-in rate of each liquid crystal display panel of the liquid crystal display device according to Example 2 of one embodiment of the present invention.

FIG. 9 is a diagram illustrating a seizure phenomenon that occurs in a conventional liquid crystal display device using the capacitively coupled HT method.

Explanation of symbols

2 TFT substrate

4 Counter substrate

6 Liquid crystal layer

10, 11 Glass substrate

12 Gate bus line

14 Drain bus line

16, 17 pixel electrode

16a, 16b, 16c, 17a, 17b linear electrode

16d, 17c fine slit

18 Storage capacity bus line

19 Storage capacitor electrode

20 TFT

21 Drain electrode

22 Source electrode

24, 25 contact hole

26 Control capacitor electrode Insulation film

Protective film

CF resin layer

Common electrode

51 Alignment film

, 53 polymer layer

Gate bus line drive circuit Drain bus line drive circuit Control circuit

, 87 Polarizer

Knock light unit

Claims

The scope of the claims

[1] a pair of substrates arranged opposite to each other;

A liquid crystal layer sandwiched between the pair of substrates;

A pixel electrode formed on one of the substrates, having a direct coupling portion electrically connected to the switching element formed on the one substrate, and a capacitive coupling portion electrically insulated from the switching element When,

A control capacitance electrode electrically connected to the switching element and forming a capacitance with the capacitive coupling portion;

An alignment film formed on each of the opposing surfaces of the pair of substrates;

A polymerizable layer contained in the liquid crystal layer is polymerized by heat or light and formed in the vicinity of the interface with the substrate, and a polymer layer for preventing seizure covering the entire alignment film on the capacitive coupling portion;

A liquid crystal display device comprising:

[2] The liquid crystal display device according to claim 1,

The entire surface of the alignment film is covered with the polymer layer.

A liquid crystal display device.

[3] In the liquid crystal display device according to claim 1 or 2,

The polymer layer has a thickness of 130 Am or more.

A liquid crystal display device.

[4] The liquid crystal display device according to any one of claims 1 to 3,

The polymerizable component has a concentration of 0.2% or more.

A liquid crystal display device.