WO2014097979A1 - Liquid crystal display device - Google Patents

Abstract

The present invention provides a liquid crystal display device which is capable of achieving good display characteristics even if the pixels are reduced in size. A liquid crystal display device of the present invention is provided with: a first substrate; a second substrate; and a liquid crystal layer that is sandwiched between the first substrate and the second substrate. The liquid crystal layer contains a liquid crystal material having a positive dielectric anisotropy. The first substrate comprises a first hook-like electrode and a second hook-like electrode that are independent from each other, and the inner contour of the first hook-like electrode and the inner contour of the second hook-like electrode face each other when the first substrate is viewed in plan.

Description

Liquid crystal display

The present invention relates to a liquid crystal display device. More specifically, the present invention relates to a horizontal electric field type liquid crystal display device.

A liquid crystal display device is a device that controls transmission / blocking of light (display on / off) by controlling the orientation of liquid crystal molecules having birefringence. The liquid crystal alignment mode of the liquid crystal display device includes a TN (Twisted Nematic) mode in which liquid crystal molecules having positive dielectric anisotropy are aligned in a twisted state of 90 ° when viewed from the substrate normal direction, and a negative dielectric constant. Vertical alignment (VA) mode in which liquid crystal molecules having anisotropy are vertically aligned with respect to the substrate surface, and liquid crystal molecules having positive or negative dielectric anisotropy are horizontally aligned with respect to the substrate surface. Examples include an in-plane switching (IPS) mode in which a lateral electric field is applied to the layer and a fringe field switching (FFS) mode.

As a driving method of a liquid crystal display device, an active matrix driving method is widely used in which an active element such as a thin film transistor (TFT) is arranged for each pixel to realize high image quality. In an array substrate including a plurality of TFTs and pixel electrodes, a plurality of scanning signal lines and a plurality of data signal lines are formed so as to intersect each other, and a TFT is provided at each of these intersections. The TFT is connected to the pixel electrode, and the supply of an image signal to the pixel electrode is controlled by the switching function of the TFT. The array substrate or the counter substrate is further provided with a common electrode, and a voltage is applied to the liquid crystal layer through the pair of electrodes.

Among the methods for controlling the alignment of liquid crystal molecules by applying a lateral electric field, in the IPS mode, the pixel electrode and the common electrode are formed on the same substrate, and both electrodes are formed to have a plurality of comb teeth. The comb teeth of the pixel electrode and the comb teeth of the common electrode in one pixel are parallel to each other, and the orientation of the liquid crystal molecules is controlled based on the potential difference between the comb teeth of the pixel electrode and the comb teeth of the common electrode. The comb teeth of each electrode may be configured such that a part thereof is bent, whereby excellent viewing angle characteristics can be obtained (see, for example, Patent Documents 1 to 3).

Japanese Patent No. 3427611 Japanese Patent No. 3383205 JP 2003-280037 A

In view of the current trend toward higher pixel definition, the present inventors have conducted various studies on the design when the pixel size is reduced, and the conventional lateral electric field method (IPS mode, It has been found that there is a case where sufficient transmittance cannot be secured in the electrode structure of the FFS mode or the like. FIG. 69 is a schematic plan view showing an example of electrode arrangement of a conventional IPS mode liquid crystal display device. As shown in FIG. 69, in a conventional IPS mode liquid crystal display device, a pixel electrode 111 and a common electrode 115 are arranged in one pixel, and each of them is a bent (V-shaped) comb. Has multiple teeth. Thus, the wide viewing angle characteristic can be obtained by arranging the longitudinal directions of the comb teeth of the electrodes 111 and 115 to be oblique with respect to the wirings.

However, in the case of adopting such a V-shaped comb tooth, the number of comb teeth that can be formed is limited as the pixel size is reduced, so that transmission per pixel is limited. The rate drops. This is because the liquid crystal molecules located far away from the electrode are not sufficiently spread in the electric field, and the desired alignment cannot be obtained. As a result, the region located at the corner of the pixel is actually a dark region (the dotted region in the rightmost diagram in FIG. 69). If the pixel size is sufficiently large, even if a dark region occurs in some part, it is possible to obtain a bright display as a whole by supplementing the brightness in other regions, but as the pixel size decreases, Since the ratio of the area occupied by the dark region to the entire pixel becomes large, the influence of a decrease in transmittance appears more remarkably when the pixel has a higher definition.

On the other hand, in order to match the comb teeth of the pixel electrode 111 and the common electrode 115 to the shape of the pixel, it is conceivable to use a straight line instead of a square shape. The effect cannot be obtained sufficiently.

In the first place, it is conceivable to use another mode instead of the IPS mode. However, when the pixel size is reduced, a high transmittance is obtained only in the TN mode, and the TN mode has a problem in viewing angle characteristics. There is. Thus, at present, there is no means for achieving both high transmittance and wide viewing angle characteristics.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a liquid crystal display device capable of obtaining good display characteristics even when the pixel size is reduced.

The present inventors paid attention to the structure of the pixel electrode and the common electrode. As in the prior art, simply changing the shape of the comb teeth of the pixel electrode and the common electrode has a high transmittance and a wide viewing angle characteristic. Judging that balancing is difficult. In the past, attention was paid to the fact that one pixel was constituted by a combination of a pixel electrode having a plurality of comb teeth and a common electrode, and a liquid crystal material having a positive dielectric anisotropy was used. As a result of intensive studies on the use, the shape of each of the pixel electrode and the common electrode is adjusted so that a part of the pixel electrode and the common electrode have a square shape when the substrate is viewed in a plane, and These electrodes are arranged so that the inner lines at the corners of each of the electrode-like electrodes face each other, and the alignment of liquid crystal molecules is controlled by a pair of saddle-like electrodes. And it has been found that by arranging the electrodes in this way, the orientation of the liquid crystal molecules can be controlled with a small number of electrodes, and the case where the pixel size is small can be dealt with.

Thus, the present inventors have conceived that the above problems can be solved brilliantly, and have reached the present invention.

That is, one aspect of the present invention includes a first substrate, a second substrate, and a liquid crystal layer sandwiched between the first substrate and the second substrate, and the liquid crystal layer has a positive dielectric constant anisotropy. The first substrate has a first saddle-like electrode and a second saddle-like electrode independent of each other, and when the first substrate is viewed in plan view, The inner line of the first bowl-shaped electrode and the inner line of the second bowl-shaped electrode are liquid crystal display devices facing each other.

The liquid crystal display device includes a first substrate, a second substrate, and a liquid crystal layer sandwiched between the first substrate and the second substrate. The first substrate has a first hook-shaped electrode and a second hook-shaped electrode which are independent from each other. An electric field is formed in the liquid crystal layer based on the potential difference between the first and second bowl-shaped electrodes. Then, the orientation of the liquid crystal molecules changes according to the strength of the electric field, the amount of light transmission is adjusted, and the on / off of the display is adjusted. The magnitude of the potential supplied to the first and second saddle-shaped electrodes is not particularly limited and can be appropriately adjusted depending on the design.

In this specification, the “saddle-shaped electrode” refers to an electrode having a bent part (corner part) and parts (end parts) located on both sides so as to sandwich the corner part. Further, when the first substrate is viewed in a plane, a line constituting the outer edge of the side (acute angle side) bent to the inside of the “saddle electrode” is referred to as an “inner line”, The line that forms the outer edge of the side that is bent outward (obtuse angle side) is referred to as the “outline”.

The configuration of the liquid crystal display device is not particularly limited by other components as long as such components are essential. For example, an electrode different from the first and second saddle-shaped electrodes (for example, third and fourth electrodes) may be provided, and the other electrode is a saddle-shaped electrode. Also, it does not have to be a saddle electrode.

Hereinafter, preferred embodiments of the liquid crystal display device will be described in detail. In addition, the form which combined two or more each preferable form of the said liquid crystal display device described below is also a preferable one form of the said liquid crystal display device.

In order to further improve the alignment controllability of the liquid crystal molecules, it is preferable that the tip of at least one end of the first saddle-shaped electrode is pointed when the first substrate is viewed in plan. It is more preferable that the tip of the end portion of the is sharp. Further, when the first substrate is viewed in plan, it is preferable that the tip of at least one end of the second bowl-shaped electrode is sharp, and the tips of both ends are sharp. Is more preferable. Thereby, the alignment disorder of the liquid crystal hardly occurs in the vicinity of the end portion of each saddle-shaped electrode, and thereby, highly uniform liquid crystal orientation can be obtained in the entire region surrounded by the pair of saddle-shaped electrodes.

In order to further enhance the alignment controllability of the liquid crystal molecules, when the first substrate is viewed in plan, the inner line of the first saddle-shaped electrode is composed of at least three lines having different angles. Preferably it is. In addition, when the first substrate is viewed in plan, it is preferable that the inner lines of the second bowl-shaped electrode are composed of at least three lines having different angles. This makes it difficult for liquid crystal alignment to occur in the vicinity of the corners of each saddle-shaped electrode, whereby highly uniform liquid crystal alignment can be obtained in the entire region surrounded by the pair of saddle-shaped electrodes. Further, in order to further enhance the alignment controllability of the liquid crystal molecules, any one of at least three lines having different angles of the inner line of the first saddle-shaped electrode, and the first It is preferable that any one of at least three lines having different angles of the inner lines of the two hook-shaped electrodes is parallel.

In order to further increase the degree of design freedom, when the first substrate is viewed in plan, two of at least three lines having different angles of the inner contour line of the first saddle electrode Are preferably perpendicular to each other. In addition, when the first substrate is viewed in plan, at least two lines out of at least three lines having different angles of the inner line of the second bowl-shaped electrode may be perpendicular to each other. preferable. According to such an electrode arrangement, the influence of the enclosure on the liquid crystal molecules controlled by the electric field formed between the first and second saddle electrodes is increased, and as a result, the initial alignment Regardless of the orientation, the configuration is such that substantially the same transmittance and viewing angle characteristics can be obtained, and the degree of freedom in design is improved.

In order to further improve the alignment controllability of the liquid crystal molecules, it is preferable that the inner contour line of the first saddle-shaped electrode is curved when the first substrate is viewed in plan. In addition, when the first substrate is viewed in a plan view, it is preferable that the contour line of the second bowl-shaped electrode is curved. This makes it difficult for liquid crystal alignment to occur in the vicinity of the corners of each saddle-shaped electrode, whereby highly uniform liquid crystal alignment can be obtained in the entire region surrounded by the pair of saddle-shaped electrodes.

In order to further improve the alignment controllability of the liquid crystal molecules, when the first substrate is viewed in plan, the first saddle-like electrode and the second saddle-like electrode are the first saddle-like shape. It is preferable that they have a line-symmetric relationship with respect to a straight line passing between the electrode and the second saddle electrode. Thereby, the symmetry of the electric field formed by the pair of bowl-shaped electrodes is improved, and highly uniform liquid crystal alignment can be obtained.

In order to further improve the alignment controllability of the liquid crystal molecules, when the first substrate is viewed in plan, the first saddle-like electrode and the second saddle-like electrode are the first saddle-like shape. It is preferable that they have a point-symmetric relationship with respect to a point located between the electrode and the second saddle electrode. Thereby, the symmetry of the electric field formed by the pair of bowl-shaped electrodes is improved, and highly uniform liquid crystal alignment can be obtained.

It is preferable that the first hook-shaped electrode and the second hook-shaped electrode are arranged on the same layer. Even when the first saddle-shaped electrode and the second saddle-shaped electrode are formed on different layers, it is possible to form a horizontal electric field, but the vertical component is partially included. In fact, an oblique electric field is formed. In this case, some liquid crystal molecules may rotate obliquely according to the electric field, thereby reducing the transmittance and viewing angle characteristics. By arranging the first saddle-shaped electrode and the second saddle-shaped electrode on the same layer, it becomes difficult to form such an oblique component electric field, so that a more uniform lateral electric field can be formed. It is possible to prevent a decrease in transmittance and viewing angle characteristics.

In order to further improve the viewing angle characteristics, the first substrate has a plurality of electrode pairs including the first saddle-shaped electrode and the second saddle-shaped electrode, and is included in each of two adjacent electrode pairs. It is preferable that the first saddle-shaped electrode and the second saddle-shaped electrode are arranged so as to be line-symmetric with respect to each other with a straight line passing between the electrode pairs as a reference axis. Here, the saddle electrode located farther from the reference axis is the “first saddle electrode”, and the saddle electrode located closer is the “second saddle electrode”. To do. A signal having the same potential is supplied to each first saddle-shaped electrode and each second saddle-shaped electrode respectively included in two adjacent electrode pairs. With such an electrode arrangement, even if the pixel size is reduced, the electric field formed by each electrode pair can be symmetrical, and a wide viewing angle characteristic can be obtained without reducing the transmittance. Can do.

It is preferable that the liquid crystal display device further includes a scanning signal line passing between the second saddle-shaped electrodes included in the two adjacent electrode pairs. The region between the second saddle-shaped electrodes included in the two electrode pairs adjacent to each other cannot be used as a display because no potential difference occurs. Therefore, an efficient configuration can be obtained by arranging scanning signal lines using this region.

Preferably, the liquid crystal display device further includes a switching element connected to each of the second bowl-shaped electrodes included in the two adjacent electrode pairs. Since these two second saddle electrodes are supplied with the same potential, this provides an efficient configuration. In particular, when the pixel size is reduced, the effect is great because the size of the switching element is directly linked to the size of the aperture ratio.

The first substrate further includes a first polarizing plate, the second substrate further includes a second polarizing plate, the polarization axis of the first polarizing plate, and the second polarizing plate The polarization axis is orthogonal, and when the first substrate is viewed in plan, the inner line of the first saddle-shaped electrode is the polarization axis of the first polarizing plate and the second polarization axis. Preferably, the polarizing plate is disposed so as to form an angle with respect to the polarization axis of the polarizing plate, and when the first substrate is viewed in plan, the inner line of the second bowl-shaped electrode is It is preferable that the first polarizing plate and the second polarizing plate are arranged so as to form an angle with respect to the polarization axis of the first polarizing plate. That is, in this embodiment, the first polarizing plate and the second polarizing plate are in a crossed Nicols arrangement relationship with each other. Since an electric field is formed between the first bowl-shaped electrode and the second bowl-shaped electrode, by adjusting the axis of each polarizing plate so as to form an angle with respect to the direction of the electric field, Good gradation display and white display can be obtained.

When the first substrate is viewed in plan, the outline of the first bowl-shaped electrode, the extended lines from both ends of the outline of the first bowl-shaped electrode, and the second bowl-shaped It is preferable that the aspect ratio of the shape of the region surrounded by the outer line of the electrode and the extended lines from both ends of the outer line of the second saddle electrode is 1. The obtained viewing angle characteristics vary depending on the shape of a certain range of regions virtually formed by the first saddle-shaped electrode and the second saddle-shaped electrode. The design that provides the best viewing angle characteristics is when the shape of the region is square, that is, when the vertical and horizontal ratio of the region is 1: 1. In the present specification, “rectangular” or “square” refers to a shape that can recognize four sides that are substantially orthogonal to or parallel to each other, and a minute unevenness may be formed in part.

According to the present invention, it is possible to obtain a liquid crystal display device capable of obtaining good display characteristics even when the pixel size is reduced.

It is a cross-sectional schematic diagram of the liquid crystal display device of Embodiment 1, and represents when no voltage is applied. It is a cross-sectional schematic diagram of the liquid crystal display device of Embodiment 1, and represents the time of white voltage application. 3 is a schematic plan view of a TFT substrate of the liquid crystal display device of Embodiment 1. FIG. FIG. 3 is a schematic plan view in which the position of a black matrix is added to the schematic plan view of the TFT substrate of Embodiment 1. FIG. 2 is a schematic diagram illustrating a configuration of a pixel assumed in Example 1 and represents a TFT substrate side. FIG. 2 is a schematic diagram illustrating a configuration of a pixel assumed in Example 1 and represents a counter substrate side. FIG. 3 is a plan view (half pixel portion) showing pixel electrodes and common electrodes extracted in Example 1-1. 2 is a simulation plane image (half pixel) showing the behavior of liquid crystal molecules in Example 1-1. In Example 1-1, it is a planar image (for half pixels) in which the light transmittance is expressed in monochrome gradation. FIG. 10 is a planar image obtained by removing the black matrix in FIG. 9 and adding electrode positions. FIG. 6 is a graph showing viewing angle characteristics in Example 1-1. It is a simulation image (for 1 pixel) which shows the behavior of the liquid crystal molecule in Example 1-2, and represents a cross-sectional image when no voltage is applied (0 V). It is a simulation image (for 1 pixel) which shows the behavior of the liquid crystal molecule in Example 1-2, and represents a planar image when no voltage is applied (0 V). It is a simulation image (for 1 pixel) which shows the behavior of the liquid crystal molecule | numerator in Example 1-2, and represents the cross-sectional image at the time of white voltage application (6.5V). It is a simulation image (for 1 pixel) which shows the behavior of the liquid crystal molecule | numerator in Example 1-2, and represents the planar image at the time of white voltage application (6.5V). In Example 1-2, it is a planar image (for one pixel) in which light transmittance is expressed in monochrome gradation. 6 is a graph showing viewing angle characteristics in Example 1-2. 6 is a schematic plan view of a TFT substrate of a liquid crystal display device of Embodiment 2. FIG. It is a cross-sectional image showing the simulation image which shows the behavior of the liquid crystal molecule at the time of white voltage application (6.5V) of Example 2. It is a plane image showing the simulation image which shows the behavior of the liquid crystal molecule at the time of white voltage application (6.5V) of Example 2. In Example 2, it is the plane image which represented the light transmittance with the monochrome gradation. The black matrix in FIG. 21 is excluded, and the position of the electrode is added. 10 is a graph showing viewing angle characteristics in Example 2. 6 is a schematic plan view of a TFT substrate of a liquid crystal display device according to Embodiment 3. FIG. It is a cross-sectional image showing the simulation image which shows the behavior of the liquid crystal molecule at the time of the white voltage application of Example 3 (11.3V). It is a plane image showing the simulation image which shows the behavior of the liquid crystal molecule at the time of the white voltage application of Example 3 (11.3V). In Example 3, it is the plane image which represented the light transmittance with the monochrome gradation. The black matrix in FIG. 27 is excluded, and the position of the electrode is added. 10 is a graph showing viewing angle characteristics in Example 3. 6 is a schematic plan view of a TFT substrate of a liquid crystal display device of Embodiment 4. FIG. 6 is a schematic plan view in which the position of a black matrix is added to the schematic plan view of a TFT substrate of Embodiment 4. FIG. FIG. 10 is a plan view showing extracted pixel electrodes and common electrodes in Example 4. 6 is a simulation plane image showing the behavior of liquid crystal molecules in Example 4. In Example 4, it is the plane image which represented the transmittance | permeability of light with the monochrome gradation. FIG. 35 is a planar image obtained by removing the black matrix in FIG. 34 and adding electrode positions. FIG. 10 is a graph showing viewing angle characteristics in Example 4. 6 is a schematic plan view of a TFT substrate of a liquid crystal display device of Embodiment 5. FIG. FIG. 10 is a schematic plan view in which the position of a black matrix is added to the schematic plan view of the TFT substrate of Embodiment 5. FIG. 10 is a plan view showing extracted pixel electrodes and common electrodes in Example 5. 10 is a simulation plane image showing the behavior of liquid crystal molecules in Example 5. In Example 5, it is the plane image which represented the light transmittance with the monochrome gradation. FIG. 42 is a planar image obtained by removing the black matrix in FIG. 41 and adding electrode positions. FIG. 10 is a graph showing viewing angle characteristics in Example 5. 7 is a schematic plan view of a TFT substrate of a liquid crystal display device according to Embodiment 6. FIG. FIG. 10 is a schematic plan view in which the position of a black matrix is added to the schematic plan view of the TFT substrate of Embodiment 6. FIG. 10 is a plan view showing extracted pixel electrodes and common electrodes in Example 6. 10 is a simulation plane image showing the behavior of liquid crystal molecules in Example 6. In Example 6, it is the plane image which represented the light transmittance with the monochrome gradation. FIG. 49 is a planar image obtained by removing the black matrix in FIG. 48 and adding electrode positions. FIG. 10 is a graph showing viewing angle characteristics in Example 6. FIG. 10 is a schematic plan view of a TFT substrate of a liquid crystal display device according to a seventh embodiment. FIG. 10 is a schematic plan view in which the position of a black matrix is added to the schematic plan view of the TFT substrate of Embodiment 7. FIG. 10 is a plan view showing extracted pixel electrodes and common electrodes in Example 7-1. It is a simulation plane image which shows the behavior of the liquid crystal molecule in Example 7-1. In Example 7-1, it is the plane image which expressed the light transmittance with the monochrome gradation. FIG. 56 is a planar image obtained by removing the black matrix in FIG. 55 and adding electrode positions. FIG. It is a graph showing the viewing angle characteristic in Example 7-1. It is a simulation plane image which shows the behavior of the liquid crystal molecule in Example 7-2. In Example 7-2, this is a planar image in which light transmittance is expressed in monochrome gradation. FIG. 60 is a planar image obtained by removing the black matrix in FIG. 59 and adding electrode positions. FIG. It is a graph showing the viewing angle characteristic in Example 7-2. FIG. 10 is a schematic plan view of a TFT substrate of a liquid crystal display device according to an eighth embodiment. 10 is a schematic plan view in which the position of a black matrix is added to the schematic plan view of the TFT substrate of Embodiment 8. FIG. FIG. 10 is a plan view showing extracted pixel electrodes and common electrodes in Example 8. 10 is a simulation plane image showing the behavior of liquid crystal molecules in Example 8. In Example 8, it is the plane image which represented the light transmittance with the monochrome gradation. 66 is a planar image obtained by removing the black matrix in FIG. 66 and adding electrode positions. FIG. 10 is a graph showing viewing angle characteristics in Example 8. It is a plane schematic diagram which shows an example of the electrode arrangement | positioning of the liquid crystal display device of the conventional IPS mode.

Embodiments will be described below, and the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited only to these embodiments.

The liquid crystal display devices of the following embodiments 1 to 8 are specifically applicable to televisions, personal computers, mobile phones, car navigation systems, information displays, and the like.

In this specification, a region in which the orientation of liquid crystal molecules is controlled by a pixel electrode controlled by one switching element and a common electrode facing the pixel electrode is defined as one “pixel”. When one switching element contributes simultaneously to the control of a plurality of pixel electrodes, the orientation of liquid crystal molecules is controlled by each of the plurality of pixel electrodes and each of the common electrodes facing each of the plurality of pixel electrodes. The entire area becomes one “pixel”.

The effect of the present invention is noticeable when the pixel size is small. However, the present invention may be applied when the pixel size is large by providing a plurality of electrode pairs in one pixel. However, as one reference of the pixel size that can efficiently obtain the effect of the present invention, there is a case where at least one side of the pixel is 20 μm or less, and further, 17 μm or less.

Embodiment 1
1 and 2 are schematic cross-sectional views of the liquid crystal display device of Embodiment 1. FIG. FIG. 1 shows the time when no voltage is applied, and FIG. 2 shows the time when a white voltage is applied. The liquid crystal display device of Embodiment 1 includes a TFT substrate (first substrate) 10, a counter substrate (second substrate) 20, and a liquid crystal layer 40 sandwiched between the TFT substrate 10 and the counter substrate 20. The liquid crystal layer 40 contains liquid crystal molecules 41 having positive dielectric anisotropy, and the liquid crystal molecules 41 are horizontal to the surfaces of the substrates 10 and 20 when no voltage is applied and when a voltage is applied. Oriented in various directions. The TFT substrate 10 includes a support substrate 61, a TFT (switching element), a scanning signal line, a data signal line, a common signal line, a pixel electrode (second bowl-shaped electrode) 11, and a common electrode (first bowl-shaped electrode) 15. In addition, an insulating film, an alignment film, and the like that isolate each electrode and each wiring into different layers are provided. The counter substrate 20 includes a support substrate 62, a color filter, a black matrix, an alignment film, and the like. The pixel electrode 11 and the common electrode 15 are independent electrodes, and signals having different potentials are supplied to the pixel electrode 11 and the common electrode 15, respectively. Thereby, a voltage can be applied in the liquid crystal layer 40.

The pixel electrode 11 is further divided into a first pixel electrode 11a and a second pixel electrode 11b. The first pixel electrode 11a and the second pixel electrode 11b are arranged on the same layer, and an image signal (pixel potential) having the same potential is supplied to each of them. In the first embodiment, one TFT is connected to each of the first pixel electrode 11a and the second pixel electrode 11b. The first pixel electrode 11a and the second pixel electrode 11b may or may not be connected to each other by a member other than the TFT.

The common electrode 15 is further divided into a first common electrode 15a and a second common electrode 15b. The first common electrode 15a and the second common electrode 15b are arranged on the same layer, and a common signal having the same potential is supplied to each of them. The first common electrode 15a and the second common electrode 15b may or may not be connected to each other by other members.

The first pixel electrode 11a, the second pixel electrode 11b, the first common electrode 15a, and the second common electrode 15b are all disposed on the same layer. As a result, an electric field having an oblique component with respect to the substrate surface is hardly formed, so that a uniform lateral electric field can be formed, and deterioration of transmittance and viewing angle characteristics can be prevented. Examples of the member positioned in the lower layer include an insulating film formed on the support substrate 61. The insulating film may be formed of an organic material or an inorganic material, and may be a single film. There may be a plurality of films.

On the surface of the TFT substrate 10 opposite to the liquid crystal layer 40 side, a polarizing plate (first polarizing plate) is attached. A polarizing plate (second polarizing plate) is attached to the surface of the counter substrate 20 opposite to the liquid crystal layer 40 side.

The first polarizing plate attached on the surface of the TFT substrate 10 and the second polarizing plate attached on the surface of the counter substrate 20 are arranged so that their polarization axes are orthogonal to each other. Yes. The first polarizing plate and the second polarizing plate have respective polarization axes that are the first pixel electrode 11a, the second pixel electrode 11b, the first common electrode 15a, and the second common electrode 15b. It arrange | positions so that an angle may be made with respect to each inner contour line. Further, the alignment films formed on both substrates are subjected to an alignment process in a direction parallel or orthogonal to the respective polarization axes of the first polarizing plate and the second polarizing plate. As a result, when no voltage is applied, the light transmitted through the liquid crystal molecules is blocked by the polarizing plate, resulting in black display, but by applying a voltage higher than the threshold and adjusting the magnitude of the voltage, the liquid crystal molecules The amount of transmitted light can be adjusted by changing the orientation direction, and gradation display and white display can be realized. Here, “parallel” or “orthogonal” includes not only completely parallel or orthogonal, but also substantially parallel or orthogonal, for example, the direction of the alignment treatment of the polarizing plate By tilting the polarizing axis by several degrees, there are cases where advantages such as uniform alignment of liquid crystal molecules can be obtained.

3 and 4 are schematic plan views of the liquid crystal display device according to the first embodiment. FIG. 3 is a schematic plan view of the TFT substrate, and FIG. 4 is a schematic plan view of the TFT substrate with the position of the black matrix added. As shown in FIG. 3, when the TFT substrate 10 in Embodiment 1 is viewed in plan, the scanning signal lines 12 and the data signal lines 13 are arranged so as to cross each other. Near the contact point between the scanning signal line 12 and the data signal line 13, a TFT (thin film transistor) 53 is provided. A common signal line 14 extending in parallel with the scanning signal line 12 is provided between the scanning signal lines 12. The direction of the initial alignment of the liquid crystal molecules 41 is parallel to the extending direction of the scanning signal line 12 and the common signal line 14 and is orthogonal to the extending direction of the data signal line 13. The double-headed arrow in FIG. 3 represents the direction of the polarization axis of the polarizing plate.

The TFT 53 is a switching element including a semiconductor layer 54, a gate electrode 55a, a source electrode 55b, a first drain electrode 55c, and a second drain electrode 55d. A part of the scanning signal line 12 is used as it is for the gate electrode 55a. The source electrode 55 b is branched from the data signal line 13. The drain electrode is divided into a first drain electrode 55c extended toward the first pixel electrode 11a and a second drain electrode 55d extended toward the second pixel electrode 11b. The first drain electrode 55c is formed wide at a position overlapping the first pixel electrode 11a, and is connected to the first pixel electrode 11a via a first contact portion 31a penetrating the insulating film. . The second drain electrode 55d is formed wide at a position overlapping the second pixel electrode 11b, and is connected to the second pixel electrode 11b via a second contact portion 31b penetrating the insulating film. . The gate electrode 55a and the semiconductor layer 54 overlap each other with a gate insulating film interposed therebetween. The source electrode 55b is connected to the drain electrodes 55c and 55d through the semiconductor layer 54, and the amount of current flowing through the semiconductor layer 54 is adjusted by the scanning signal input to the gate electrode through the scanning signal line 12, and the data signal Transmission of image signals inputted in order of the source electrode 55b, the semiconductor layer 54, the first drain electrode 55c or the second drain electrode 55d, and the first pixel electrode 11a or the second pixel electrode 11b through the line 13 is performed. Be controlled.

As shown in FIG. 3, each of the first pixel electrode 11a and the second pixel electrode 11b has a bowl shape, and each has a line-symmetric shape with respect to an axis. Further, both the first pixel electrode 11a and the second pixel electrode 11b have pointed tips. Further, in both the first pixel electrode 11a and the second pixel electrode 11b, the inner line is composed of at least three lines (five lines in FIG. 3) having different angles, and is located in the middle. The line to be cut is orthogonal to the bisector (axisymmetric axis of symmetry) of each electrode. In addition, the inner lines of the first pixel electrode 11a and the second pixel electrode 11b are curved as a whole.

As shown in FIG. 3, the first common electrode 15a and the second common electrode 15b are both bowl-shaped, and each has a line-symmetric shape with respect to a certain axis. In addition, both the first common electrode 15a and the second common electrode 15b have pointed ends. Furthermore, the inner line of each of the first common electrode 15a and the second common electrode 15b is composed of at least three lines (five lines in FIG. 3) having different angles, and is located in the middle. The line to be cut is orthogonal to the bisector (axisymmetric axis of symmetry) of each electrode. Further, the inner lines of the first common electrode 15a and the second common electrode 15b are curved as a whole.

As shown in FIG. 3, the first pixel electrode 11 a and the first common electrode 15 a are opposed to each other, and the respective contour lines have portions parallel to each other. . The second pixel electrode 11b and the second common electrode 15b are opposed to each other in outline lines, and each outline line has a portion parallel to each other.

The scanning signal line 12 is formed so as to pass between the first pixel electrode 11a and the second pixel electrode 11b. The first common electrode 15a is arranged to overlap the first common signal line 14a with an insulating film interposed therebetween. The first common electrode 15a is connected to the first common signal line 14a through a first contact portion 32a that penetrates the insulating film. The second common electrode 15b is disposed so as to overlap the second common signal line 14b with an insulating film interposed therebetween. The second common electrode 15b is connected to the second common signal line 14b through a second contact portion 32b that penetrates the insulating film. The first common signal line 14a and the second common signal line 14b may be connected to each other through, for example, a common bus line, but are connected to each other as long as the same potential is supplied. It does not have to be. In the first embodiment, it is not always necessary to provide a common signal line separately from the common electrode.

As shown in FIG. 3, the combination of the first pixel electrode 11a and the first common electrode 15a and the combination of the second pixel electrode 11b and the second common electrode 15b each constitute one set of electrode pairs. A plurality of such electrode pairs are formed on the TFT substrate 10.

The combination of the first pixel electrode 11a and the first common electrode 15a is in a line-symmetric relationship with respect to a straight line passing between the electrodes 11a and 15a, and between the electrodes 11a and 15a. They are point-symmetric with respect to the point located.

The combination of the second pixel electrode 11b and the second common electrode 15b is in a line symmetrical relationship with respect to a straight line passing between the electrodes 11b and 15b, and between the electrodes 11b and 15b. They are point-symmetric with respect to the point located.

Further, with respect to these electrode pairs, the first pixel electrode 11a, the second pixel electrode 11a, the second pixel electrode 11a, and the second pixel electrode 11b are symmetrical with respect to each other about a straight line passing between the first pixel electrode 11a and the second pixel electrode 11b. The arrangement of the pixel electrode 11b, the first common electrode 15a, and the second common electrode 15b is determined. In the first embodiment, all of the first pixel electrode 11a, the second pixel electrode 11b, the first common electrode 15a, and the second common electrode 15b are different in direction and have the same dimensions. is there.

The length from one end to the other end of each of the first pixel electrode 11a, the second pixel electrode 11b, the first common electrode 15a, and the second common electrode 15b (the length of the outline) The length of the contour line) varies depending on the pixel size to be set, but is set in the range of 10 to 20 μm, for example. Further, the width of each of the first pixel electrode 11a, the second pixel electrode 11b, the first common electrode 15a, and the second common electrode 15b varies depending on the size and location of the pixel to be set. The part is set in a range of 2 μm.

As shown in FIG. 3, each pixel includes an outline of the first pixel electrode 11a, an extension line from both ends of the outline of the first pixel electrode 11a, and an outline of the first common electrode 15a. A region surrounded by extended lines from both ends of the contour line of the first common electrode 15a (hereinafter also referred to as a first divided region D1), a contour line of the second pixel electrode 11b, A region surrounded by an extension line from both ends of the outline of the second pixel electrode 11b, an outline of the second common electrode 15b, and an extension line from both ends of the outline of the second common electrode 15b ( Hereinafter, it is also referred to as a second divided region D2.). An area located between the first divided area D1 and the second divided area D2 (hereinafter also referred to as an intermediate area D3) is also a part of the pixel.

In FIG. 3, the first pixel electrode 11a is located at the lower right of the first divided region D1, the first common electrode 15a is located at the upper left of the first divided region D1, and the second pixel electrode 11b. Is located on the upper right side of the second divided region D2 and the second common electrode 15b is located on the lower left side of the second divided region D2. The position is not particularly limited as long as the contour lines face each other.

As shown in FIG. 4, the black matrix 51 is provided with openings in accordance with regions where the orientation of liquid crystal molecules is controlled by the respective electrodes. That is, the black matrix 51 is formed so that the outer edge of the opening is formed along the first divided region D1 and the second divided region D2. As a result, the black matrix 51 forms a lattice shape when viewed as a whole. The intermediate region D3 is also covered with the black matrix 51. The plurality of openings formed so as to be surrounded by the black matrix 51 thus serve as a region that transmits display light.

As shown in FIG. 4, notches are provided at the four corners of the opening of the black matrix 51. Specifically, each corner of the opening of the black matrix 51 has an outline of the adjacent first pixel electrode 11a, first common electrode 15a, second pixel electrode 11b, or second common electrode 15b. It has a part parallel to.

In the example shown in FIG. 4, the opening of the black matrix 51 is set slightly smaller than the first divided region D1 and the second divided region D2. Preferably, the length of one side of the first divided region D1 and the second divided region D2 is not less than 110% and not less than one side of the opening formed along these.

As shown in FIGS. 3 and 4, when no voltage is applied, the liquid crystal molecules 41 are composed of the first pixel electrode 11a, the second pixel electrode 11b, the first common electrode 15a, and the second common electrode. It is oriented to form an angle with respect to each bisector of 15b. 3 and 4, the white dotted arrow indicates the orientation direction (major axis direction) of the liquid crystal molecules when no voltage is applied.

On the other hand, as shown in FIG. 3 and FIG. 4, when white voltage is applied, the liquid crystal molecules are the first pixel electrode 11a, the second pixel electrode 11b, the first common electrode 15a, and the second common electrode. The electrodes 15b are oriented in directions parallel or perpendicular to the bisectors. The black arrows in FIGS. 3 and 4 indicate the orientation direction (major axis direction) of the liquid crystal molecules when a white voltage is applied.

In the first embodiment, both the first divided region D1 and the second divided region D2 have a rectangle or a square. Thereby, excellent transmittance and wide viewing angle characteristics can be obtained.

Furthermore, in the first embodiment, (i) the point of the end of each electrode is pointed, (ii) each electrode itself has a line-symmetric shape with respect to a certain axis, (iii) ) The inner line of each electrode is composed of at least three lines having different angles, and the line located in the middle is orthogonal to the bisector of each electrode, (iv) Pixel The combination of the electrode and the common electrode has a symmetrical structure (specifically, line symmetry, point symmetry), (v) the electrode pair constituting the first divided region D1, and the second divided The electrode pair constituting the region D2 has a symmetrical structure (specifically, line symmetry), (vi) the size of each electrode constituting one pixel is the same, etc. It contributes to high transmittance and wide viewing angle characteristics. Furthermore, in the first embodiment, the lengths of the contour lines at both ends and corners of each electrode are shorter than in the embodiments described later. Moreover, the outline of each electrode is curved as a whole. When a liquid crystal material having a positive dielectric anisotropy is used, the most uniform orientation can be obtained under such conditions.

When a specific simulation was actually performed assuming the liquid crystal display device of Embodiment 1, the following results were obtained (Example 1). 5 and 6 are schematic diagrams illustrating the configuration of the pixel assumed in the first embodiment. FIG. 5 illustrates the TFT substrate side, and FIG. 6 illustrates the counter substrate side. The simulation conditions of Example 1 were set as follows. As the dielectric anisotropy of the liquid crystal material, a positive type (Δε = + 10) was used. The pixel size was 15 μm × 45 μm. The lengths of the outlines at both ends of the pixel electrode and the common electrode were 2 μm, respectively. Each inner line of the pixel electrode and the common electrode is composed of five lines having different angles, and the angles formed by the lines are all obtuse. Thereby, the area | region which an electric field radiates | emits locally can be eliminated. More specifically, among the five lines, the angle formed by the line located in the middle (hereinafter also referred to as the corner outline) and the lines located on both sides thereof was 157 °. In addition, the corner outline line connecting the outline lines at each end and the outline line at each end form an angle of 30 °. The distance between the pixel electrode and the common electrode (specifically, the length of a straight line connecting the innermost corner of the pixel electrode and the innermost corner of the common electrode) is 8.5 (= 6√2) μm. A margin of 2 μm was taken from the outer edge of the pixel to the outline of each electrode. The length of the vertical side and the length of the horizontal side of the first divided region D1 and the second divided region D2 were both 11 μm. Therefore, the aspect ratio of each divided region D1 and D2 is 1: 1. The size of the opening of the black matrix was 7 μm × 7 μm, and four corners were chamfered with right-angled isosceles triangles having a base of 1 μm. That is, the aspect ratio of the opening of the black matrix is 1: 1.

In this way, the pixel electrode and the common electrode are shaped like bowls and arranged so as to surround the opening of the black matrix with a certain interval therebetween, so that the pixel electrode, the common electrode, and the tips of these ends are arranged. In a virtual region formed by being surrounded by lines formed by connecting each other, the direction of the electric field can be controlled to a desired direction while preventing the generation of a local electric field. Furthermore, by gradually changing the inclinations of the inner lines of the pixel electrode and the common electrode, the rate of change in the direction of the electric field can be reduced, and the occurrence of liquid crystal alignment disorder can be suppressed.

When a specific simulation was actually performed assuming the liquid crystal display device of Embodiment 1, the following results were obtained (Example 1). 7 to 17 are images or graphs showing the simulation results of Example 1. FIG. As the liquid crystal material, a material having positive dielectric anisotropy is used. 7 to 11 show the results (Example 1-1) in which only half-pixels are extracted and simulated.

As shown in FIG. 7, when a voltage is applied between the pixel electrode and the common electrode, lines of electric force are generated from the common electrode toward the pixel electrode. Compared with the case of Example 1, the electrode itself is small and the region surrounded by the electrode is narrow, but in the range surrounded by the extension line connecting the ends of each electrode, each of the lines of electric force is substantially straight. Has occurred. For this reason, an electric field with excellent uniformity is formed, and the liquid crystal molecules are aligned according to this, so that alignment with excellent uniformity can be obtained.

FIG. 8 is a simulation plane image showing the behavior of the liquid crystal molecules in Example 1-1. As shown in FIG. 8, most of the liquid crystal molecules included in the first divided region D1 are aligned in a direction of about 45 ° with respect to the initial alignment direction, and the change in angle is smooth. And it is uniform. Similarly, most of the liquid crystal molecules included in the second divided region D2 are aligned in a direction of about 45 ° with respect to the initial alignment direction, and the change in angle is smooth and uniform. It has become. In addition, as shown in FIG. 8, the boundary of the equipotential region is formed in an elliptical shape for the electric field in the vicinity of each electrode.

FIG. 9 is a plane image in which light transmittance is expressed in monochrome gradation in Example 1-1, and FIG. 10 is obtained by excluding the black matrix in FIG. 9 and adding electrode positions. FIG. 11 is a graph showing viewing angle characteristics in Example 1-1. As shown in FIG. 9 and FIG. 10, in Example 1-1, light is uniformly transmitted over the entire area serving as the opening of the black matrix, and high transmittance can be secured. Recognize. As for the viewing angle characteristics, as shown in FIG. 11, although there is a slight difference in the change in luminance depending on the angle, the end portions of each curve converge at the same place, so that the lower order is particularly low. It can be seen that in the tone and the high gradation, a substantially uniform display is obtained no matter what angle the viewing angle is inclined. Note that the graph shown in FIG. 11 is a simulation result focusing only on one set of the combination of the pixel electrode and the common electrode. The combination of the pixel electrode and the common electrode is taken as one electrode pair, and two sets of electrode pairs are used. When simulation is performed, better viewing angle characteristics can be obtained. This will be described in detail below.

12 to 17 show the results of simulation for one pixel (Example 1-2). 12 and 13 show the case when no voltage is applied (0 V), and FIGS. 14 and 15 show the case when a white voltage is applied (6.5 V). 12 and 14 represent cross-sectional images, and FIGS. 13 and 15 represent planar images. FIG. 16 is a planar image showing the light transmittance in monochrome gradation in Example 1-2, and FIG. 17 is a diagram showing the viewing angle characteristics in Example 1-2. Is a reference plane, the polar angle is fixed at 45 °, and each azimuth value is expressed as a luminance.

As shown in FIGS. 12 and 13, when no voltage is applied, the liquid crystal molecules 41 are uniformly oriented in the short side direction of the pixel. On the other hand, as shown in FIGS. 14 and 15, when a voltage equal to or higher than the threshold is applied, the liquid crystal molecules 41 located in the region between the first pixel electrode 11a and the second pixel electrode 11b The initial alignment is maintained in the vicinity of the TFT substrate 10 on which the electrode 11a and the second pixel electrode 11b are arranged, but the alignment changes in the vicinity of the counter substrate 20. In addition, the liquid crystal molecules 41 positioned between the pixel electrodes 11a and 11b and the common electrodes 15a and 15b facing the pixel electrodes 11a and 11b have different angles depending on the distance from each electrode. Oriented to face. In FIG. 14 and FIG. 15, each region is indicated by gradation according to the strength of the electric field.

As shown in FIGS. 13 and 15, the outline of the first pixel electrode 11a, the extended line from both ends of the first pixel electrode 11a, the outline of the first common electrode 15a, and the first Although the liquid crystal molecules 41 included in the first divided region D1 surrounded by the extended lines from both ends of the outer line of the common electrode 15a have different angles depending on the region, most of them are orthogonal to the inner line of each electrode. That is, it is oriented in a direction of about 45 ° with respect to the initial orientation, and the change in angle is smooth and uniform. Similarly, both the outer line of the second pixel electrode 11b, the extended line from both ends of the second pixel electrode 11b, the outer line of the second common electrode 15b, and the outer line of the second common electrode 15b. Although the liquid crystal molecules 41 included in the second divided region D2 surrounded by the extended line from the end are different in angle depending on the region, most of them are perpendicular to the inner line of each electrode, that is, with respect to the initial alignment. Is oriented in a direction of about 45 °, and the change in the angle is smooth and uniform. Note that most of the liquid crystal molecules 41 included in the intermediate region D3 surrounded by the first divided region D1 and the second divided region D2 maintain the initial alignment, but some of the liquid crystal molecules 41 are in the initial state. It is oriented obliquely with respect to the orientation.

Further, a characteristic point here is that the alignment distribution (director distribution) of the liquid crystal molecules 41 is a straight line passing between the first pixel electrode 11a and the second pixel electrode 11b, more specifically, In other words, the lines are symmetrical with respect to each other about a straight line that bisects one pixel. As a result, in a region corresponding to one pixel in the liquid crystal layer, two regions including a plurality of liquid crystal molecules having alignment orientations in different directions and having a symmetrical alignment pattern around a certain reference axis ( Multidomain) can be formed.

As described above, according to the configuration of the first embodiment, the alignment of the liquid crystal molecules can be made uniform in the portion used as the display region, and two regions having alignment orientations in different directions can be formed. Therefore, it is possible to efficiently use light and obtain excellent viewing angle characteristics. In addition, according to the configuration of the first embodiment, even if the pixel size is designed to be small, an excellent effect that the characteristics are not deteriorated can be exhibited.

With respect to the transmittance, as shown in FIG. 16, it can be seen that light is uniformly transmitted through the entire region serving as the opening of the black matrix 51, and a high transmittance can be secured. As for the viewing angle characteristics, as shown in FIG. 17, since there is no great difference in luminance depending on the angle and the end portions of the curves converge at the same place, the viewing angle can be set at any angle. Even if it is tilted, it can be seen that there is no change in appearance and that excellent viewing angle characteristics can be obtained.

In the first embodiment, the aspect ratio of the first divided area D1 and the second divided area D2 and the aspect ratio of the opening of the black matrix 51 are not necessarily matched as shown in the first embodiment. There is no need. The shape of the opening of the black matrix 51 may be determined according to a region suitable for display, and is not limited to a rectangle or a square. Further, the magnitude relationship between the size of the first divided region D1 and the second divided region D2 and the size of the opening of the black matrix 51 is not particularly limited.

Hereinafter, materials and manufacturing methods of other members will be described.

As the material of the support substrates 61 and 62, a transparent material such as glass or plastic is preferably used. As a material for the insulating film, a transparent material such as silicon nitride, silicon oxide, or photosensitive acrylic resin is preferably used. As the insulating film, for example, a silicon nitride film is formed by a plasma-enhanced chemical vapor deposition (PECVD) method, and a photosensitive acrylic resin film is formed on the silicon nitride film by a die coating (coating) method. It is formed by film formation. The holes provided in the insulating film for forming the contact portions 31 and 32 can be formed by performing dry etching (channel etching).

Various electrodes constituting the scanning signal line 12, the data signal line 13, and the TFT 53 are formed of a single layer or a plurality of layers of a metal such as titanium, chromium, aluminum, molybdenum, or an alloy thereof by a sputtering method or the like. The film can be formed and then patterned by photolithography or the like. For these various wirings and electrodes formed on the same layer, the same material is used to make the manufacturing more efficient.

As the semiconductor layer 54 of the TFT 53, for example, a high resistance semiconductor layer (i layer) made of amorphous silicon, polysilicon or the like, and a low resistance semiconductor layer made of n ⁺ amorphous silicon or the like in which amorphous silicon is doped with an impurity such as phosphorus or the like ( n ⁺ layer), but the can be used as a laminate of, as the other, IGZO (indium - gallium - zinc - oxygen) oxide semiconductor such as is preferably used.

By using an oxide semiconductor such as IGZO as the material of the semiconductor layer 54, the electron mobility is high and the size of the TFT 53 can be reduced, so that a large aperture ratio can be secured. Therefore, an oxide semiconductor using IGZO is advantageous when reducing the size of a pixel. In addition, since the off-leakage characteristic is low, the charge can be held for a long time, and the advantage that low frequency driving is possible can be obtained.

The pixel electrode 11 and the common electrode 15 are formed by sputtering a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), tin oxide (SnO), or an alloy thereof. After a single layer or a plurality of layers are formed by a method or the like, patterning can be performed using a photolithography method or the like.

As a material for the color filter, a photosensitive resin (color resist) that transmits light corresponding to each color is preferably used. The material of the black matrix 51 is not particularly limited as long as it has a light shielding property, and a resin material containing a black pigment or a metal material having a light shielding property is preferably used. The color filter and the black matrix 51 may be arranged not on the counter substrate 20 side but on the TFT substrate 10 side.

The TFT substrate 10 and the counter substrate 20 manufactured in this way are provided with a plurality of columnar spacers made of an insulating material on one substrate, and then bonded to each other using a sealing material. A liquid crystal layer 40 is formed between the TFT substrate 10 and the counter substrate 20, but when the dropping method is used, the liquid crystal material is dropped before the substrates are bonded, and the vacuum injection method is used. The liquid crystal material is injected after the substrates are bonded.

And a liquid crystal display device is completed by affixing a polarizing plate, retardation film, etc. on the surface on the opposite side to the liquid crystal layer 40 side of each board | substrate. Furthermore, a gate driver, a source driver, a display control circuit, and the like are mounted on the liquid crystal display device, and a liquid crystal display device corresponding to the application is completed by combining a backlight and the like.

Embodiment 2
The second embodiment is the same as the first embodiment except that the initial alignment direction of the liquid crystal molecules is different. Specifically, the direction of the initial alignment of the liquid crystal molecules in the second embodiment is exactly opposite to the direction of the initial alignment of the liquid crystal molecules in the first embodiment. FIG. 18 is a schematic plan view of a TFT substrate of the liquid crystal display device according to the second embodiment. In FIG. 18, each electrode is not a single electrode pair made up of a pixel electrode and a common electrode, but two pairs of electrode pairs made up of a pixel electrode and a common electrode (that is, one pixel).

When simulation was performed assuming the liquid crystal display device of Embodiment 2, the following results were obtained (Example 2). The simulation conditions of Example 2 are the same as those of Example 1 except for the orientation of the initial orientation. In Example 2, the initial orientation is 180 ° different from that in Example 1. That is, in Example 1, the initial orientation is set to the right direction, but in Example 2, the initial orientation is set to the left direction. 19 and 20 show simulation images showing the behavior of liquid crystal molecules when white voltage is applied (6.5 V) in Example 2, FIG. 19 is a cross-sectional image, and FIG. 20 is a planar image. FIG. 21 is a plane image in which light transmittance is expressed in monochrome gradation in the second embodiment, and FIG. 22 is obtained by excluding the black matrix in FIG. 21 and adding electrode positions. FIG. 23 is a graph showing viewing angle characteristics in Example 2, and represents each luminance when the polar angle is fixed at 45 ° and the value of the azimuth angle is changed with the display screen as a reference plane.

As shown in FIG. 19 and FIG. 20, when a voltage equal to or higher than the threshold is applied, the liquid crystal molecules 41 located in the region between the first pixel electrode 11a and the second pixel electrode 11b are changed to the first pixel electrode 11a. The initial orientation is maintained in the vicinity of the TFT substrate 10 on which the second pixel electrode 11b is disposed, but the orientation changes in the vicinity of the counter substrate 20. In addition, the liquid crystal molecules 41 positioned between the pixel electrodes 11a and 11b and the common electrodes 15a and 15b facing the pixel electrodes 11a and 11b have different angles depending on the distance from each electrode. Oriented to face. In FIG. 19 and FIG. 20, each region is indicated by gradation according to the strength of the electric field.

As shown in FIGS. 19 and 20, as in the first embodiment, the orientation distribution (director distribution) of the liquid crystal molecules 41 passes between the first pixel electrode 11a and the second pixel electrode 11b. The lines are symmetrical with respect to each other about a straight line, more specifically, a straight line that bisects one pixel. As a result, in a region corresponding to one pixel in the liquid crystal layer, two regions including a plurality of liquid crystal molecules having alignment orientations in different directions and having a symmetrical alignment pattern around a certain reference axis ( Multidomain) can be formed.

As can be seen by comparing the result of Example 1 and the result of Example 2, the same characteristics can be obtained regardless of the horizontal direction as long as the initial orientation is horizontal. Further, by using two electrode pairs each including a pixel electrode and a common electrode, display characteristics can be improved as compared with a case where only a pair of electrode pairs each including a pixel electrode and a common electrode is used. Specifically, the alignment of the liquid crystal molecules can be made uniform in the portion that becomes the transmission region, and two regions having alignment orientations in different directions can be formed, so that light can be used efficiently. In addition, excellent viewing angle characteristics can be obtained. Further, even if the pixel size is designed to be small, an excellent effect that the characteristics are not deteriorated can be exhibited.

With respect to the transmittance, as shown in FIG. 21, it can be seen that light is uniformly transmitted through the entire region serving as the opening of the black matrix 51, and a high transmittance can be secured. Further, as shown in FIG. 22, even if the black matrix is not taken into consideration, a circular transmission region occupying a certain range is formed. With respect to the viewing angle characteristics, as shown in FIG. 23, since there is no great difference in luminance depending on the angle, and the end portion of each curve converges at the same location, the viewing angle is inclined to any angle. However, it can be seen that there is no change in appearance and that excellent viewing angle characteristics can be obtained.

As described above, according to the second embodiment, it was confirmed that excellent transmittance and viewing angle characteristics equivalent to those of the first embodiment can be obtained.

Embodiment 3
Embodiment 3 is the same as Embodiment 1 or 2 except that the orientation of the initial alignment of liquid crystal molecules is different. Specifically, the direction of the initial alignment of the liquid crystal molecules in the third embodiment is orthogonal to the direction of the initial alignment of the liquid crystal molecules in the first or second embodiment. FIG. 24 is a schematic plan view of a TFT substrate of the liquid crystal display device according to the third embodiment. In FIG. 24, each electrode is not a single electrode pair consisting of a pixel electrode and a common electrode, but represents two electrode pairs consisting of a pixel electrode and a common electrode (that is, one pixel).

When a specific simulation was actually performed assuming the liquid crystal display device of Embodiment 3, the following results were obtained (Example 3). The simulation conditions of Example 3 are the same as those of Example 1 or 2 except for the orientation of the initial orientation. In Example 3, the initial orientation is 90 ° different from that in Examples 1 and 2. That is, in Example 1, the initial orientation is set to the right direction, and in Example 2, the initial orientation is set to the left direction. In Example 3, the initial orientation is set to the upward direction. 25 and 26 show simulation images showing the behavior of liquid crystal molecules when white voltage is applied (11.3 V) in Example 3, FIG. 25 is a cross-sectional image, and FIG. 26 is a planar image. FIG. 27 is a planar image in which light transmittance is expressed in monochrome gradation in Example 3, and FIG. 28 is obtained by excluding the black matrix in FIG. 27 and adding electrode positions. FIG. 29 is a graph showing viewing angle characteristics in Example 3, and shows each luminance when the polar angle is fixed at 45 ° and the value of the azimuth angle is changed with the display screen as a reference plane.

As shown in FIGS. 25 and 26, when a voltage equal to or higher than the threshold value is applied, the liquid crystal molecules 41 located in the region between the first pixel electrode 11a and the second pixel electrode 11b are changed to the first pixel electrode 11a. The initial orientation is maintained in the vicinity of the TFT substrate 10 on which the second pixel electrode 11b is disposed, but the orientation changes in the vicinity of the counter substrate 20. In addition, the liquid crystal molecules 41 positioned between the pixel electrodes 11a and 11b and the common electrodes 15a and 15b facing the pixel electrodes 11a and 11b have different angles depending on the distance from each electrode. Oriented to face. In FIG. 25 and FIG. 26, each region is indicated by gradation according to the strength of the electric field.

25 and 26, the outline of the first pixel electrode 11a, the extended line from both ends of the first pixel electrode 11a, the outline of the first common electrode 15a, and the first Although the liquid crystal molecules 41 included in the first divided region D1 surrounded by the extended lines from both ends of the outer line of the common electrode 15a have different angles depending on the region, most of them are along the inner line of each electrode. That is, it is oriented in a direction of about 45 ° with respect to the initial orientation, and the change in angle is smooth and uniform. Similarly, both the outer line of the second pixel electrode 11b, the extended line from both ends of the second pixel electrode 11b, the outer line of the second common electrode 15b, and the outer line of the second common electrode 15b. Although the liquid crystal molecules 41 included in the second divided region D2 surrounded by the extension line from the end have different angles depending on the region, most of them are along the inner line of each electrode, that is, with respect to the initial alignment. It is oriented in the direction of about 45 °, and the change in angle is smooth and uniform. Note that most of the liquid crystal molecules 41 included in the intermediate region D3 surrounded by the first divided region D1 and the second divided region D2 maintain the initial alignment, but some of the liquid crystal molecules 41 are in the initial state. It is oriented obliquely with respect to the orientation.

As for the transmittance, as shown in FIG. 27, there is a region that is slightly dark at a part of the opening of the black matrix 51. As can be seen from FIG. 28, this is because the region surrounded by the pair of electrodes and the portion that becomes the transmission region are slightly different. However, it can be seen that sufficient transmittance can be secured when viewed as the entire region of the opening.

With respect to the viewing angle characteristics, as shown in FIG. 29, compared to Example 1, there is a slight difference in the change in luminance depending on the angle, and at the high gradation, the end portion of each curve is located at the same place. Since it is not converged, disturbance may occur when the angle is changed, but it is acceptable as a whole.On the other hand, with low gradation, almost uniform display can be obtained regardless of the angle of view. You can see that

From the above, it was confirmed that sufficient transmittance and viewing angle characteristics can be obtained also in the third embodiment.

Embodiment 4
The fourth embodiment is the same as the first embodiment except that the shapes of the pixel electrode and the common electrode are different. In the fourth embodiment, the ratio of the end portion in each electrode is larger than that in the first embodiment. The outline of each electrode is curved as a whole. FIG. 30 is a schematic plan view of the TFT substrate of the liquid crystal display device according to the fourth embodiment, and FIG.

When a specific simulation was actually performed assuming the liquid crystal display device of Embodiment 4, the following results were obtained (Example 4). FIG. 32 is a plan view illustrating pixel electrodes and common electrodes extracted from the fourth embodiment. The simulation conditions of Example 4 are the same as those of Example 1 except for the shapes of the pixel electrode and the common electrode. The lengths of the outlines at both ends of the pixel electrode and the common electrode were 4 μm, respectively. Each inner line of the pixel electrode and the common electrode is composed of five lines having different angles, and the angles formed by the lines are all obtuse. More specifically, among the five lines, the angle formed by the line located in the middle (inner corner line) and the lines located on both sides thereof was 152 °. In addition, the corner outline line connecting the outline lines at each end and the outline line at each end form an angle of 30 °. The distance between the pixel electrode and the common electrode (specifically, the length of a straight line connecting the innermost corner of the pixel electrode and the innermost corner of the common electrode) is 8.5 (= 6√2) μm.

FIG. 33 is a simulation plane image showing the behavior of liquid crystal molecules in Example 4. As shown in FIG. 33, the liquid crystal molecules contained in the first divided region D1 are oriented in a direction of about 45 ° with respect to the orientation of the initial orientation, although the angles differ depending on the region. The change in angle is smooth and uniform. Similarly, although the liquid crystal molecules contained in the second divided region D2 vary in angle depending on the region, most of them are aligned in a direction of about 45 ° with respect to the initial alignment direction, and the change in angle is smooth. And it is uniform. As shown in FIG. 33, the boundary of the equipotential region is formed in a triangular shape for the electric field near each electrode.

FIG. 34 is a plane image in which light transmittance is expressed in monochrome gradation in Example 4, and FIG. 35 is obtained by excluding the black matrix in FIG. 34 and adding electrode positions. FIG. 36 is a graph showing viewing angle characteristics in Example 4. As shown in FIGS. 34 and 35, it can be seen that in Example 4, light is uniformly transmitted through the entire region serving as the opening of the black matrix, and high transmittance can be secured. As for the viewing angle characteristics, as shown in FIG. 36, compared with Example 1, although the luminance changes slightly depending on the angle, the end portions of the curves converge to the same place. From this, it can be seen that, in particular, in the low gradation and the high gradation, almost uniform display is obtained regardless of the angle of view. The graph shown in FIG. 36 is a simulation result paying attention to only one combination of the pixel electrode and the common electrode. Also in Example 4, the combination of the pixel electrode and the common electrode is set as one electrode pair, and two sets are obtained. When the simulation is performed using the electrode pair, the same result as the simulation result shown in FIG. 17 shown in the first embodiment can be obtained.

From the above, it was confirmed that excellent transmittance and viewing angle characteristics can be obtained also in the fourth embodiment. In the fourth embodiment, the description has been made on the assumption that the alignment process is performed in the horizontal direction. However, the alignment process may be performed in the vertical direction as in other embodiments.

Embodiment 5
The fifth embodiment is the same as the first embodiment except that the shapes of the pixel electrode and the common electrode are different and that the distance between the pixel electrode and the common electrode is shortened. That is, the outline of each electrode is curved as a whole. FIG. 37 is a schematic plan view of the TFT substrate of the liquid crystal display device of Embodiment 5, and FIG. 38 is a view in which the position of the black matrix is further added.

When a specific simulation was actually performed assuming the liquid crystal display device of Embodiment 5, the following results were obtained (Example 5). FIG. 39 is a plan view showing pixel electrodes and common electrodes extracted from the fifth embodiment. The simulation conditions of Example 5 are the same as those of Example 1 except for the distance between the pixel electrode and the common electrode. The lengths of the contour lines at both ends of the pixel electrode and the common electrode were 3 μm, respectively. Each inner line of the pixel electrode and the common electrode is composed of five lines having different angles, and the angles formed by the lines are all obtuse. More specifically, among the five lines, the angle formed by the line located in the middle (the contour line of the corner) and the lines located on both sides thereof was 157 °. In addition, the corner outline line connecting the outline lines at each end and the outline line at each end form an angle of 30 °. The distance between the pixel electrode and the common electrode (specifically, the length of the line segment connecting the innermost corner of the pixel electrode and the innermost corner of the common electrode) is 7.1 ( = 5√2) μm.

40 is a simulation plane image showing the behavior of liquid crystal molecules in Example 5. FIG. As shown in FIG. 40, the liquid crystal molecules included in the first divided region D1 are partially disclinated along the inner line of each electrode, but most of them are formed. It is oriented in a direction of about 45 ° with respect to the initial orientation direction, and the change in angle is smooth and uniform. Similarly, some of the liquid crystal molecules included in the second divided region D2 have disclinations along the inner lines of the electrodes, but most of them are in the initial alignment direction. Is oriented in a direction of about 45 °, and the change in the angle is smooth and uniform. As shown in FIG. 40, the boundary between equipotential regions is formed in a triangular shape for the electric field near each electrode.

FIG. 41 is a planar image in which light transmittance is expressed in monochrome gradation in Example 5, and FIG. 42 is obtained by excluding the black matrix in FIG. 41 and adding electrode positions. FIG. 43 is a graph showing viewing angle characteristics in Example 5. As shown in FIGS. 41 and 42, in Example 5, the transmittance is slightly reduced near the corner of the region serving as the opening of the black matrix. However, as a whole, sufficient transmittance is obtained. It can be seen that it is secured. Further, as shown in FIG. 43, the viewing angle characteristics are slightly different in luminance change depending on the angle as compared with the first embodiment, but the end portions of the curves converge to the same place. From this, it can be seen that, in particular, in the low gradation and the high gradation, almost uniform display is obtained regardless of the angle of view. The graph shown in FIG. 43 is a simulation result paying attention to only one combination of the pixel electrode and the common electrode. Also in Example 5, the combination of the pixel electrode and the common electrode is set as one electrode pair, and two sets are obtained. When the simulation is performed using the electrode pair, the same result as the simulation result shown in FIG. 17 shown in the first embodiment can be obtained.

From the above, it was confirmed that sufficient transmittance and viewing angle characteristics can be obtained also in the fifth embodiment. In the fifth embodiment, the description is given on the assumption that the alignment process is performed in the horizontal direction. However, the alignment process may be performed in the vertical direction as in other embodiments.

Embodiment 6
The sixth embodiment is the same as the first embodiment except that the shapes of the pixel electrode and the common electrode are different. In the sixth embodiment, the contour lines at the ends of the electrodes are designed to be perpendicular to each other and along the opening of the black matrix. Thereby, the inner line of each electrode is bent as a whole. FIG. 44 is a schematic plan view of the TFT substrate of the liquid crystal display device of Embodiment 6, and FIG. 45 is a view in which the position of the black matrix is further added.

When a specific simulation was actually performed assuming the liquid crystal display device of Embodiment 6, the following results were obtained (Example 6). FIG. 46 is a plan view illustrating pixel electrodes and common electrodes extracted from the sixth embodiment. The simulation conditions of Example 6 are the same as those of Example 1 except for the shapes of the pixel electrode and the common electrode. The lengths of the outlines at both ends of the pixel electrode and the common electrode were each 4.5 μm. Each inner line of the pixel electrode and the common electrode is composed of five lines having different angles, and the angles formed by the lines are all obtuse. More specifically, among the five lines, the angle formed by the line located in the middle (inner corner line) and the lines located on both sides thereof was set to 135 °. In addition, the corner outline line connecting the outline lines at each end and the outline line at each end form an angle of 45 °. The distance between the pixel electrode and the common electrode (specifically, the length of a straight line connecting the innermost corner of the pixel electrode and the innermost corner of the common electrode) is 8.5 (= 6√2) μm.

FIG. 47 is a simulation plane image showing the behavior of liquid crystal molecules in Example 6. As shown in FIG. 47, the liquid crystal molecules included in the first divided region D1 include two lines in which the inner lines of the respective electrodes are substantially perpendicular to each other. In comparison, although the range in which the desired orientation could be obtained was small, most of the orientation was oriented in the direction of about 45 ° with respect to the orientation of the initial orientation, and the change in angle was smooth and uniform. ing. Similarly, the liquid crystal molecules contained in the second divided region D2 are formed so that the inner lines of the respective electrodes are substantially perpendicular to each other. Although the range in which the orientation could be obtained is small, most are oriented along the inner line of each electrode in the direction of about 45 ° with respect to the orientation of the initial orientation, and the change in angle is smooth, And it is uniform. In addition, as shown in FIG. 47, the boundary of the equipotential region is formed in a triangular shape for the electric field near each electrode.

FIG. 48 is a planar image in which light transmittance is expressed in monochrome gradation in Example 6, and FIG. 49 is obtained by excluding the black matrix in FIG. 48 and adding electrode positions. FIG. 50 is a graph showing viewing angle characteristics in Example 6. As shown in FIG. 48 and FIG. 49, in Example 6, the transmittance is slightly decreased near the corner of the region serving as the opening of the black matrix. However, when viewed as a whole, sufficient transmittance is obtained. It can be seen that it is secured. In addition, as shown in FIG. 50, the viewing angle characteristics are slightly different in luminance change depending on the angle as compared with Example 1, but the end portions of the curves converge to the same place. Therefore, it can be seen that, in particular, in the low gradation and the high gradation, almost uniform display is obtained regardless of the angle of view. The graph shown in FIG. 50 is a simulation result paying attention to only one set of the pixel electrode and the common electrode. Also in Example 5, the combination of the pixel electrode and the common electrode is one electrode pair, and two sets are obtained. When the simulation is performed using the electrode pair, the same result as the simulation result shown in FIG. 17 shown in the first embodiment can be obtained.

From the above, it was confirmed that sufficient transmittance and viewing angle characteristics can be obtained also in the sixth embodiment. In the sixth embodiment, since the inner lines of each electrode include two lines that are perpendicular to each other, substantially the same display characteristics can be obtained regardless of whether the initial alignment of the liquid crystal molecules is set in the vertical direction or the horizontal direction. And the advantage that the degree of freedom in design is high can be obtained. Details will be described in Embodiment 7 below.

Embodiment 7
The seventh embodiment is the same as the first embodiment except that the shapes of the pixel electrode and the common electrode are different. In the seventh embodiment, the contour lines at the ends of the electrodes are designed to be perpendicular to each other and along the opening of the black matrix, and the length of the end of each electrode is the same as in the first embodiment. It is longer than that. The inner line of each electrode is bent as a whole. FIG. 51 is a schematic plan view of the TFT substrate of the liquid crystal display device according to the seventh embodiment, and FIG. 52 is obtained by further adding the position of the black matrix.

When a specific simulation was actually performed assuming the liquid crystal display device of Embodiment 7, the following results were obtained (Example 7-1). FIG. 53 is a plan view illustrating pixel electrodes and common electrodes extracted from Example 7-1. The simulation conditions of Example 7-1 are the same as those of Example 1 except for the shapes of the pixel electrode and the common electrode. The lengths of the outlines at both ends of the pixel electrode and the common electrode were each 6.7 μm. Each inner line of the pixel electrode and the common electrode is composed of five lines having different angles, and the angles formed by the lines are all obtuse. More specifically, among the five lines, the angle formed by the line located in the middle (inner corner line) and the lines located on both sides thereof was set to 135 °. In addition, the corner outline line connecting the outline lines at each end and the outline line at each end form an angle of 45 °. The distance between the pixel electrode and the common electrode (specifically, the length of a straight line connecting the innermost corner of the pixel electrode and the innermost corner of the common electrode) is 8.5 (= 6√2) μm.

FIG. 54 is a simulation plane image showing the behavior of liquid crystal molecules in Example 7-1. As shown in FIG. 54, since the liquid crystal molecules included in the first divided region D1 include two lines in which the inner lines of the electrodes are substantially perpendicular, In comparison, although the range in which the desired orientation could be obtained was small, most of the orientation was oriented in the direction of about 45 ° with respect to the orientation of the initial orientation, and the change in angle was smooth and uniform. ing. Similarly, the liquid crystal molecules included in the second divided region D2 include two lines in which the inner lines of the respective electrodes are substantially perpendicular, and therefore, compared with the cases of the first to fourth embodiments. Although the range in which this orientation could be obtained is small, the orientation is approximately 45 ° with respect to the orientation of the initial orientation so that most of the orientation is along the contour line of each electrode, and the change in angle is smooth. And uniform. As shown in FIG. 54, for the electric field in the vicinity of each electrode, the boundary of the equipotential region is formed in a triangular shape.

FIG. 55 is a planar image in which light transmittance is expressed in monochrome gradation in Example 7-1. FIG. 56 is obtained by excluding the black matrix in FIG. 55 and adding the electrode positions. FIG. 57 is a graph showing viewing angle characteristics in Example 7-1. As shown in FIG. 55 and FIG. 56, in Example 7-1, the transmittance is slightly reduced near the corner of the region serving as the opening of the black matrix. It can be seen that the rate is secured. As for the viewing angle characteristics, as shown in FIG. 57, compared with Example 1, although the luminance changes slightly depending on the angle, the end portions of the curves converge at the same place. Therefore, it can be seen that, in particular, in the low gradation and the high gradation, almost uniform display is obtained regardless of the angle of view. The graph shown in FIG. 57 is a simulation result paying attention to only one combination of the pixel electrode and the common electrode. In Example 7-1, the combination of the pixel electrode and the common electrode is one electrode pair, When a simulation is performed using two sets of electrode pairs, a result similar to the simulation result shown in FIG.

From the above, it was confirmed that sufficient transmittance and viewing angle characteristics can be obtained also in the seventh embodiment. In the seventh embodiment, since the inner lines of each electrode include two lines that are perpendicular to each other, substantially the same display characteristics can be obtained regardless of whether the initial alignment of the liquid crystal molecules is set in the vertical direction or the horizontal direction. Can be obtained, and there is an advantage that the degree of freedom in design is increased.

The embodiment 7 is further tested (Example 7-2) to verify the case where the orientation of the initial orientation is changed. Specifically, in Example 7-1, the orientation of the initial orientation was set to the lateral direction (rightward) as in Example 1. However, in Example 7-2, as in Example 3, The initial orientation is set to the vertical direction (upward).

FIG. 58 is a simulation plane image showing the behavior of liquid crystal molecules in Example 7-2. As shown in FIG. 58, the liquid crystal molecules included in the first divided region D1 include two lines in which the inner lines of the respective electrodes are substantially perpendicular. Compared to the above, although the range in which the desired orientation could be obtained is small, most are oriented in the direction of about 45 ° with respect to the orientation of the initial orientation so as to be along the inner line of each electrode, The change in angle is smooth and uniform. Similarly, the liquid crystal molecules included in the second divided region D2 include two lines in which the inner lines of the respective electrodes are substantially perpendicular, and therefore, compared with the cases of the first to fourth embodiments. Although the range in which this orientation could be obtained is small, the orientation is approximately 45 ° with respect to the orientation of the initial orientation so that most of the orientation is along the contour line of each electrode, and the change in angle is smooth. And uniform. As shown in FIG. 58, for the electric field near each electrode, the boundary of the equipotential region is formed in a triangular shape.

FIG. 59 is a plane image in which light transmittance is expressed in monochrome gradation in Example 7-2, and FIG. 60 is obtained by excluding the black matrix in FIG. 59 and adding electrode positions. FIG. 61 is a graph showing viewing angle characteristics in Example 7-2. As shown in FIG. 59 and FIG. 60, in Example 7-2, the transmittance is slightly reduced near the corner of the region serving as the opening of the black matrix. It can be seen that the rate is secured. In addition, as shown in FIG. 61, the viewing angle characteristics are slightly different in luminance change depending on the angle as compared with Example 1, but the end portions of the curves converge to the same place. From this, it can be seen that, in particular, in the low gradation and the high gradation, almost uniform display is obtained regardless of the angle of view. The graph shown in FIG. 61 is a simulation result paying attention to only one combination of the pixel electrode and the common electrode. Also in Example 7-2, the combination of the pixel electrode and the common electrode is set as one electrode pair. When a simulation is performed using two sets of electrode pairs, a result similar to the simulation result shown in FIG.

As can be seen by comparing FIG. 55 and FIG. 59 and FIG. 56 and FIG. 60, they form substantially the same transmittance distribution, although their initial orientations are different. From this, according to Embodiment 7, it can be seen that, regardless of whether the initial alignment of the liquid crystal molecules is set in the vertical direction or the horizontal direction, substantially the same transmittance can be obtained and the degree of freedom in design is high. .

Embodiment 8
The eighth embodiment is the same as the first embodiment except that the shapes of the pixel electrode and the common electrode are different and that the distance between the pixel electrode and the common electrode is short. In the eighth embodiment, the contour lines at the ends of the electrodes are designed to be perpendicular to each other and along the opening of the black matrix, and the length of the contour lines at the corners of the electrodes. Is longer than that of the first embodiment, and the distance between the pixel electrode and the common electrode is shorter. The inner line of each electrode is bent as a whole. FIG. 62 is a schematic plan view of the TFT substrate of the liquid crystal display device of Embodiment 8, and FIG. 63 is a view in which the position of the black matrix is further added.

When a specific simulation was actually performed assuming the liquid crystal display device of Embodiment 8, the following results were obtained (Example 8). FIG. 64 is a plan view showing pixel electrodes and common electrodes extracted from the eighth embodiment. The simulation conditions of Example 8 are the same as those of Example 1 except for the shapes of the pixel electrode and the common electrode. The lengths of the outlines at both ends of the pixel electrode and the common electrode were each 4.5 μm. Each inner line of the pixel electrode and the common electrode is composed of five lines having different angles, and the angles formed by the lines are all obtuse. More specifically, among the five lines, the angle formed by the line located in the middle (inner corner line) and the lines located on both sides thereof was set to 135 °. In addition, the corner outline line connecting the outline lines at each end and the outline line at each end form an angle of 45 °. The distance between the pixel electrode and the common electrode (specifically, the length of a straight line connecting the innermost corner of the pixel electrode and the innermost corner of the common electrode) is 7.1 (= 5√2) μm.

FIG. 65 is a simulation plane image showing the behavior of liquid crystal molecules in Example 8. As shown in FIG. 65, the liquid crystal molecules included in the first divided region D1 include two lines in which the inner lines of the respective electrodes are substantially perpendicular. Compared with, the range in which the desired orientation could be obtained is small, but most of them are oriented in the direction of about 45 ° with respect to the orientation of the initial orientation, and the change in angle is smooth and uniform. It has become. Similarly, the liquid crystal molecules included in the second divided region D2 include two lines in which the inner lines of the respective electrodes are substantially perpendicular, and therefore, compared with the cases of the first to fourth embodiments. However, most of them are oriented in the direction of about 45 ° with respect to the initial orientation direction, and the change of the angle is smooth and uniform. As shown in FIG. 65, the boundary between equipotential regions is formed in a triangular shape for the electric field near each electrode.

FIG. 66 is a planar image in which light transmittance is expressed in monochrome gradation in Example 8, and FIG. 67 is obtained by excluding the black matrix in FIG. 66 and adding electrode positions. FIG. 68 is a graph showing viewing angle characteristics in Example 8. As shown in FIGS. 66 and 67, in Example 8, the transmittance is slightly reduced near the corner of the region serving as the opening of the black matrix. However, when viewed as a whole, sufficient transmittance is obtained. It can be seen that it is secured. As for the viewing angle characteristics, as shown in FIG. 68, compared with Example 1, although the luminance changes slightly depending on the angle, the end portions of the curves converge to the same place. Therefore, it can be seen that, in particular, in the low gradation and the high gradation, almost uniform display is obtained regardless of the angle of view. The graph shown in FIG. 68 is a simulation result paying attention to only one combination of the pixel electrode and the common electrode. Also in Example 8, the combination of the pixel electrode and the common electrode is one electrode pair, When the simulation is performed using the electrode pair, the same result as the simulation result shown in FIG. 17 shown in the first embodiment can be obtained.

From the above, it was confirmed that sufficient transmittance and viewing angle characteristics can be obtained also in the eighth embodiment. Also in the eighth embodiment, since the inner lines of each electrode include two lines that are perpendicular to each other, the same display is achieved regardless of whether the initial alignment of the liquid crystal molecules is set in the vertical direction or the horizontal direction. The characteristics can be obtained, and the advantage that the degree of freedom of design is increased can be obtained.

10: TFT substrate 11: Pixel electrode (second bowl-shaped electrode)
11a: first pixel electrode 11b: second pixel electrode 12: scanning signal line 13: data signal line 14: common signal line 14a: first common signal line 14b: second common signal line 15: common electrode ( First saddle electrode)
15a: first common electrode 15b: second common electrode 20: counter substrate 31, 32: contact part 31a, 32a: first contact part 31b, 32b: second contact part 40: liquid crystal layer 41: liquid crystal molecules 51: Black matrix 53: TFT
54: Semiconductor layer 55a: Gate electrode 55b: Source electrode 55c: First drain electrode 55d: Second drain electrode 61, 62: Support substrate 111: Pixel electrode (comb shape)
115: Common electrode (comb shape)
D1: First divided area D2: Second divided area D3: Intermediate area

Claims (18)

A first substrate, a second substrate, and a liquid crystal layer sandwiched between the first substrate and the second substrate,
The liquid crystal layer contains a liquid crystal material having a positive dielectric anisotropy,
The first substrate has a first hook-shaped electrode and a second hook-shaped electrode that are independent from each other,
When the first substrate is viewed in plan, the inner line of the first hook-shaped electrode and the inner line of the second hook-shaped electrode are opposed to each other. Liquid crystal display device. The liquid crystal display device according to claim 1, wherein when the first substrate is viewed in a plan view, a tip of at least one end of the first bowl-shaped electrode is pointed. 3. The liquid crystal display device according to claim 1, wherein a tip of at least one end of the second bowl-shaped electrode is pointed when the first substrate is viewed in a plan view. The inner line of the first saddle-shaped electrode is composed of at least three lines having different angles when the first substrate is viewed in a plane. The liquid crystal display device according to any one of the above. 5. The inner line of the second saddle-shaped electrode is composed of at least three lines having different angles when the first substrate is viewed in a plan view. The liquid crystal display device according to any one of the above. When the first substrate is viewed in plan, any one of at least three lines having different angles of the inner line of the first saddle-shaped electrode, and the second saddle-shaped 6. The liquid crystal display device according to claim 1, wherein any one of at least three lines having different angles among the inner lines of the electrodes is parallel. When the first substrate is viewed in a plane, two of at least three lines having different angles of the inner line of the first saddle-shaped electrode are perpendicular to each other. The liquid crystal display device according to claim 4. When the first substrate is viewed in plan, two of at least three lines having different angles of the inner line of the second bowl-shaped electrode are perpendicular to each other. The liquid crystal display device according to claim 5. The liquid crystal display device according to any one of claims 1 to 3, wherein an inner line of the first bowl-shaped electrode is curved when the first substrate is viewed in a plan view. The liquid crystal display device according to any one of claims 1 to 3, wherein an inner line of the second bowl-shaped electrode is curved when the first substrate is viewed in a plan view. When the first substrate is viewed in a plane, the first hook-shaped electrode and the second hook-shaped electrode are between the first hook-shaped electrode and the second hook-shaped electrode. 11. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is in a line-symmetric relationship with respect to a straight line passing therethrough. When the first substrate is viewed in plan, the first hook-shaped electrode and the second hook-shaped electrode are between the first hook-shaped electrode and the second hook-shaped electrode. 11. The liquid crystal display device according to claim 1, wherein the liquid crystal display device has a point-symmetrical relationship with respect to the position of the point. 13. The liquid crystal display device according to claim 1, wherein the first bowl-shaped electrode and the second bowl-shaped electrode are arranged on the same layer. The first substrate has a plurality of electrode pairs including the first hook-shaped electrode and the second hook-shaped electrode,
The first saddle-shaped electrode and the second saddle-shaped electrode respectively included in two adjacent electrode pairs are arranged so as to be symmetrical with respect to each other with a straight line passing between each electrode pair as a reference axis. ,
A saddle-like electrode located farther from the reference axis is the first saddle-like electrode, and a saddle-like electrode located closer to the reference axis is the second saddle-like electrode. 14. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is provided. 15. The liquid crystal display device according to claim 14, further comprising a scanning signal line passing between each second saddle-shaped electrode included in the two electrode pairs adjacent to each other. 16. The liquid crystal display device according to claim 14, further comprising a switching element connected to each of the second bowl-shaped electrodes included in the two electrode pairs adjacent to each other. The first substrate further includes a first polarizing plate, and the second substrate further includes a second polarizing plate,
The polarization axis of the first polarizing plate and the polarization axis of the second polarizing plate are perpendicular to each other,
When the first substrate is viewed in plan, the inner line of the first bowl-shaped electrode makes an angle with the polarization axis of the first polarizer and the polarization axis of the second polarizer. Are located in
When the first substrate is viewed in plan, the inner line of the second bowl-shaped electrode makes an angle with the polarization axis of the first polarizer and the polarization axis of the second polarizer. The liquid crystal display device according to any one of claims 1 to 16, wherein the liquid crystal display device is disposed on the surface. When the first substrate is viewed in plan, the outline of the first bowl-shaped electrode, the extended lines from both ends of the outline of the first bowl-shaped electrode, and the second bowl-shaped 18. The aspect ratio of the shape of the region surrounded by the outer line of the electrode and the extended lines from both ends of the outer line of the second saddle-shaped electrode is 1. A liquid crystal display device according to claim 1.

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