JP2006330503A - Liquid crystal display element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element which has liquid crystal aligned uniformly in one direction outside a pixel part without making the pixel part small and also prevents alignment defects of the liquid crystal. <P>SOLUTION: The liquid crystal display element has a master substrate 2 and a slave substrate 1 which are opposed to each other and has electrodes and alignment films on opposite surface sides respectively and has the nematic liquid crystal held between those substrates, and is characterized in that pretilt angles of nematic liquid crystal molecules on the interface of a 1st alignment film 4 provided on a pixel part and a non-pixel part of the master substrate 2 are equal to pretilt angles of nematic liquid crystal molecules on the interface of a second alignment film 5 provided on a non-pixel part of the slave substrate 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display element and a method for manufacturing the same, and more particularly to a bistable liquid crystal display element using a nematic liquid crystal.

  2. Description of the Related Art Conventionally, liquid crystal display devices (liquid crystal display elements) manufactured by holding a liquid crystal such as a ferroelectric liquid crystal or a bistable liquid crystal between two substrates are used for personal computers, mobile phones, and the like.

  A substrate used in the liquid crystal display element is composed of a pixel portion (pixel area) for displaying video and characters and other non-pixel portions (non-pixel area). The pixel portion is provided with a transparent electrode, and the liquid crystal is driven by applying a pulse electric field by the transparent electrode, that is, the alignment of the liquid crystal is controlled. However, the transparent electrode is not provided in the non-pixel portion. Therefore, there is a problem that in this non-pixel portion, a plurality of alignment liquid crystals are mixed to form a madara pattern.

  On the other hand, in Patent Document 1, in a ferroelectric liquid crystal display element (FLCD), a new electrode is provided outside the pixel electrode, and a predetermined voltage is applied to align the liquid crystal around the pixel electrode in one direction. A ferroelectric liquid crystal display device is described that eliminates the spotted pattern around the pixels.

  Patent Document 2 describes a liquid crystal display device in which the rubbing conditions for the upper and lower substrates are the same in the picture element portion, while the rubbing conditions for the upper and lower substrates are greatly different in the non-picture element portion. In this liquid crystal display element, the asymmetry of the alignment of the upper and lower substrates at the non-picture element portion is increased, and the alignment of the liquid crystal can be made uniform.

  Further, Patent Document 3 discloses that at least one dummy electrode is formed outside the transparent electrode arranged at the endmost part of the display area (pixel part), so that the transparent electrode is also formed in all directions at the peripheral part in the display area. Describes a liquid crystal device that is adjacent to each other and has the same pattern as the central portion of the display region. As a result, it is possible to prevent deterioration in display quality caused by specific liquid crystal behavior resulting from the shape effect of the transparent electrode pattern in the peripheral portion of the display region (pixel portion). The liquid crystal device described in Patent Document 3 is a device using chiral nematic liquid crystal having a bistable state through a Fredericks transition.

Patent Document 4 discloses a liquid crystal element in which the pretilt angle of the pixel peripheral alignment film on the upper and lower substrates is larger than that in the pixel in the FLCD. Further, Patent Document 5 discloses a liquid crystal display element using a liquid crystal material that can move along the substrate surface by applying a voltage. The pretilt angle of the pixel peripheral alignment film on the upper and lower substrates is larger than that in the pixel, A liquid crystal element having a randomly oriented region on the outside is disclosed.
JP 62-102227 A (published May 12, 1987) JP-A-2-2212828 (published on September 4, 1990) JP 2001-166322 A (published on June 22, 2001) JP 7-13167 A (published on January 17, 1995) Japanese Patent Laid-Open No. 9-329790 (published on December 22, 1997)

  In the ferroelectric liquid crystal display device described in Patent Document 1, since the electrode for switching the liquid crystal around the pixel to a specific orientation is provided, the pixel portion becomes small. Further, the liquid crystal alignment cannot be aligned in one direction further outside the electrode.

  In the ferroelectric liquid crystal display device described in Patent Document 2, since the rubbing conditions of the picture element portion and the non-picture element portion of the upper and lower substrates are aligned, if the alignment deviation of the upper and lower substrates occurs, A portion of the ferroelectric liquid crystal to be sandwiched between the alignment films is sandwiched between the alignment films having different rubbing conditions. This induces alignment defects in the ferroelectric liquid crystal. Even when a bistable liquid crystal such as a chiral nematic liquid crystal that is not a ferroelectric liquid crystal is used, alignment defects are similarly induced. Further, since the resist is applied to the surface of the alignment film by using the mask rubbing method, the alignment disorder due to the interaction between the alignment film and the resist cannot be prevented. In addition, since the two-level alignment process is performed on one substrate, the cost is increased.

  In the liquid crystal device described in Patent Document 3, since the dummy electrode is provided outside the display area, the pixel portion is reduced by the amount of the dummy electrode. Further, Uniform orientation and Twist orientation cannot be prevented from existing in the madder further outside the dummy electrode. In the liquid crystal elements described in Patent Documents 4 and 5, when the upper and lower substrates are misaligned, the ferroelectric liquid crystal that should originally be sandwiched between the alignment films under the same rubbing conditions is sandwiched between the alignment films under different rubbing conditions. Occurs. This induces alignment defects in the ferroelectric liquid crystal.

  Furthermore, in any of the above-mentioned patent documents, since the orientation of the liquid crystal outside the pixel portion is randomly oriented, it is necessary to hide a random orientation region that does not look good as a display element form, leading to an increase in cost and a narrow frame. Is impossible.

  The present invention has been made to solve the above-described problems, and its purpose is (i) without reducing the size of the pixel portion, and (ii) aligning the orientation of the liquid crystal outside the pixel portion in one direction. And (iii) to provide a liquid crystal display element in which alignment defects of the liquid crystal are prevented and a method for manufacturing the same.

  In order to solve the above problems, the liquid crystal display element of the present invention has a first substrate and a second substrate that are opposed to each other and each provided with an electrode and an alignment film on the facing surface side. In the liquid crystal display element in which the nematic liquid crystal is sandwiched, the pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided in the pixel portion and the non-pixel portion of the first substrate is provided in the non-pixel portion of the second substrate. It is characterized by being equal to the pretilt angle of nematic liquid crystal molecules at the alignment film interface.

  The method for manufacturing a liquid crystal display element of the present invention includes a first substrate and a second substrate that are opposed to each other and each provided with an electrode and an alignment film on the facing surface side, and nematic liquid crystal is formed on these substrates. In the manufacturing method of the sandwiched liquid crystal display element, the pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided in the pixel portion and the non-pixel portion of the first substrate and the non-pixel portion of the second substrate are provided. It is characterized in that the pretilt angle of the nematic liquid crystal molecules at the interface of the alignment film is made equal.

  According to the above configuration, in the non-pixel portion, the pretilt angles of nematic liquid crystal molecules at the alignment film interface between the first substrate and the second substrate are equal to each other. Therefore, the alignment of nematic liquid crystal molecules arranged between these substrates is always aligned in one direction. That is, it is possible to prevent the presence of nematic liquid crystal molecules having two or more alignment states in the non-pixel portion.

  For example, when the rubbing direction of the alignment film (direction in which the rubbing treatment is performed) is reversed by 180 degrees between the first substrate and the second substrate, the alignment state of the nematic liquid crystal molecules is anti-parallel alignment (Uniform Orientation, homogeneous orientation). On the other hand, when the rubbing direction (direction in which the rubbing process is performed) is the same between the first substrate and the second substrate, the alignment state of the nematic liquid crystal molecules is Twist alignment. That is, in the non-pixel portion, only the Uniform orientation or the Twist orientation is provided.

  Accordingly, since the alignment of the liquid crystal in the non-pixel portion is aligned in one direction, it is not necessary to provide an electrode for aligning the alignment of the liquid crystal in the non-pixel portion. Therefore, the pixel portion can be enlarged and a narrow frame can be achieved.

  The first substrate has the same pretilt angle of the nematic liquid crystal molecules at the interface of the alignment film between the pixel portion and the non-pixel portion, and this pretilt angle is the same as that of the alignment film of the non-pixel portion of the second substrate. It is equal to the pretilt angle of the nematic liquid crystal molecules at the interface. Therefore, even when alignment misalignment occurs between the first substrate and the second substrate, the alignment relationship between the alignment films of the first substrate and the second substrate in the non-pixel portion does not change. That is, in the non-pixel portion, nematic liquid crystal sandwiched between alignment films having different rubbing conditions does not occur. Accordingly, it is possible to prevent the occurrence of alignment defects in the nematic liquid crystal even when alignment misalignment occurs.

  In the liquid crystal display element of the present invention, a chiral agent is injected into the nematic liquid crystal, and the pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided in the non-pixel portion of the second substrate is It is preferable that the pretilt angle of the nematic liquid crystal molecules at the interface of the alignment film provided in the pixel portion of the second substrate is larger.

  Further, in the method for manufacturing a liquid crystal display element of the present invention, the first substrate and the second substrate that are opposed to each other and are each provided with an electrode and an alignment film are provided on the opposite surface side, and the nematic liquid crystal is formed on these substrates. In the manufacturing method of the sandwiched liquid crystal display element, the pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided in the pixel portion and the non-pixel portion of the first substrate and the non-pixel portion of the second substrate are provided. It is preferable to make the pretilt angle of the nematic liquid crystal molecules at the interface of the alignment film equal.

  According to the above configuration, the pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided in the non-pixel portion of the second substrate is equal to that of the nematic liquid crystal molecules at the alignment film interface provided in the pixel portion of the second substrate. It is larger than the pretilt angle. Therefore, in the pixel portion, the pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided on the first substrate is larger than the pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided on the second substrate. Yes. That is, in the pixel portion, the pretilt angle is different between the substrates facing each other.

  Therefore, in the initial state before applying the pulse electric field by the electrode, the alignment of the nematic liquid crystal molecules sandwiched between the first substrate and the second substrate is the Twist alignment. From this initial state, the liquid crystal disposed on the second substrate side is vertically aligned, but when a pulse electric field that does not vertically align the liquid crystal disposed on the first substrate side is applied by the electrode, the nematic liquid crystal molecules are substantially vertically aligned. Orientation.

  Here, when the electric field is gently lowered, the nematic liquid crystal molecules are in anti-parallel alignment. Conversely, when the electric field is suddenly lowered, the chiral agent injected into the nematic liquid crystal tries to twist the nematic liquid crystal molecules, and the liquid crystal tries to line up in the rubbing direction (pretilt angle direction) at the alignment film interface. Work. That is, the nematic liquid crystal molecules are in the Twist orientation. Therefore, in the pixel portion, switching between the Uniform orientation and the Twist orientation can be performed by appropriately applying a pulse electric field with the electrodes.

  In the liquid crystal display element of the present invention, the material of the alignment film in the non-pixel portion of the second substrate and the material of the alignment film in the pixel portion and the non-pixel portion of the first substrate are inorganic materials, The material of the pixel portion of the second substrate is preferably an organic material.

  In the liquid crystal display element of the present invention, it is preferable that the inorganic material is SiO while the organic material is polyimide.

  In the liquid crystal display element of the present invention, the pretilt angle of the alignment film in the non-pixel portion of the second substrate and the pretilt angle of the alignment film in the pixel portion and non-pixel portion of the first substrate are 3 ° or more. While the angle is 7 ° or less, the pretilt angle of the alignment film in the pixel portion of the second substrate is preferably 1 ° or less.

  As described above, according to the liquid crystal display element and the method for manufacturing the liquid crystal display element of the present invention, the pretilt angle of the nematic liquid crystal molecules at the interface between the alignment films provided in the pixel portion and the non-pixel portion of the first substrate is This is equal to the pretilt angle of nematic liquid crystal molecules at the interface of the alignment film provided on the non-pixel portion of the substrate.

  Therefore, it is possible to provide a liquid crystal display element in which the alignment of the liquid crystal outside the pixel portion is aligned in one direction and the alignment defect of the liquid crystal is prevented, and a method for manufacturing the same, without reducing the pixel portion. Play.

  An embodiment of the present invention will be described with reference to the drawings.

  The liquid crystal display element of this embodiment is a bistability liquid crystal display element using a nematic liquid crystal. FIG. 2A is a front view showing the liquid crystal display element of the present embodiment, and FIG. 2B is a cross-sectional view taken along the line A-A ′ of FIG.

  As shown in these drawings, the liquid crystal display element includes a slave substrate (second substrate) 1, a master substrate (first substrate) 2 facing the slave substrate 1, a seal 3, and a first orientation. The film 4, the second alignment film 5, the third alignment film 6, and the spacer 7 are included, and nematic liquid crystal (liquid crystal) is sealed inside. In addition, a chiral agent is preferably added to the liquid crystal so as to obtain a pitch that is 1/4 of the cell thickness (cell gap; distance between the slave substrate 1 and the master substrate 2). The liquid crystal display element has a transparent electrode (electrode) (not shown). The transparent electrode has a role of changing the alignment of liquid crystal molecules by applying a voltage to drive the liquid crystal.

  The slave substrate 1 and the master substrate 2 sandwich other members of the liquid crystal display element from both sides. The seal 3 mainly has a role of confining the liquid crystal inside the liquid crystal display element, and is disposed on the peripheral portion of the slave substrate 1 and the master substrate 2 on the opposite surface side. The first alignment film 4, the second alignment film 5, and the third alignment film 6 have a role of determining the alignment of the liquid crystal molecules, that is, determining the pretilt angle of the liquid crystal molecules at the interface between these alignment films. is doing.

  The first alignment film 4 is laminated in the pixel area (pixel portion; display area; pixel region; display region) and non-pixel area (non-pixel portion; non-pixel region) on the master substrate 2 while avoiding the seal 3. ing. Therefore, the liquid crystal molecules arranged on the master substrate 2 side are aligned by the first alignment film 4. The first alignment film 4 is formed so as to avoid the seal 3, but is not necessarily limited to this configuration, and the first alignment film 4 is provided on the master substrate 2, and the seal 3 is formed thereon. It may be provided.

  The second alignment film 5 is stacked on the pixel portion on the slave substrate 1. On the other hand, the third alignment film 6 is stacked on the non-pixel portion of the slave substrate 1. Therefore, the liquid crystal molecules arranged at the interface on the slave substrate 1 side are aligned by the second alignment film 5 in the pixel portion, and are aligned by the third alignment film 6 in the non-pixel portion.

  In particular, in the liquid crystal display element of the present embodiment, the pretilt angle of the liquid crystal molecules at the interface of the first alignment film 4 and the pretilt angle of the liquid crystal molecules at the interface of the third alignment film 6 are equal. If the pretilt angles are equal in this way, different materials may be used for the first alignment film 4 and the third alignment film 6. The pretilt angles of the liquid crystal molecules arranged in the non-pixel portion are equal on the slave substrate 1 side and the master substrate 2 side.

  Specifically, the pretilt angles of the liquid crystal molecules at the interface between the first alignment film 4 and the third alignment film 6 are preferably about 3 ° to 7 °. The pretilt angle of the liquid crystal molecules at the interface between the first alignment film 4 and the third alignment film 6 is more preferably about 5 °. In order to realize such a pretilt angle, the first alignment film 4 and the third alignment film 6 are preferably an STN alignment film material made of polyimide, for example.

  FIG. 3 is a schematic diagram showing the rubbing direction on the master substrate side and the slave substrate side and the alignment state of the liquid crystal molecules in the non-pixel portion of the liquid crystal display element of the present embodiment.

  The alignment film in the non-pixel portion is subjected to an alignment process so that the alignment of the liquid crystal molecules takes an anti-parallel direction (homogeneous direction). That is, the rubbing direction between the master substrate 2 side and the slave substrate 1 side is opposite by 180 ° as shown in FIG. As a result, the liquid crystal molecules are in uniform alignment as shown in FIG.

  However, the present invention is not limited to this, and the alignment film in the non-pixel portion may be subjected to an alignment process so as to take a parallel direction. That is, the rubbing directions on the master substrate 2 side and the slave substrate 1 side may be the same as shown in FIG. In this case, as shown in FIG. Therefore, as shown in FIG. 3C, the liquid crystal molecules are in the Twist orientation.

  Further, the pretilt angle of the liquid crystal molecules at the interface of the first alignment film 4 and the pretilt angle of the liquid crystal molecules at the interface of the third alignment film 6 are larger than the pretilt angle of the liquid crystal molecules at the interface of the second alignment film 5. It is desirable. In the present embodiment, for example, the pretilt angle of the second alignment film 5 is preferably 0 ° to 1 °. In order to realize such a pretilt angle, the second alignment film 5 is preferably made of an inorganic material such as SiO. The spacer 7 is disposed in order to make the cell gap uniform.

  Next, the alignment state in the non-pixel portion of the liquid crystal display element, which is the most important part of the present invention, will be described in more detail.

  As described above, in the liquid crystal display element of the present embodiment, in the non-pixel portion, the alignment films are arranged on the master substrate 2 and the slave substrate 1 so that the pretilt angles of the liquid crystal molecules are equal to each other. Further, in the non-pixel portion, the first alignment film 4 disposed on the master substrate 2 and the third alignment film 6 disposed on the slave substrate 1 are antiparallel or rubbing in which the rubbing direction is reversed by 180 °. Orientation treatment is performed so that the directions are parallel to each other.

  1A is a plan view showing a liquid crystal display element in which the rubbing direction is anti-parallel and a pulse electric field is applied by an electrode, and FIG. 1B is a plan view of B in FIG. It is -B 'sectional drawing. In addition, between the board | substrates of Fig.1 (a), the orientation mode of a liquid crystal molecule is shown by the line segment.

  When the rubbing direction of the alignment film in the non-pixel portion is anti-parallel, as shown in FIG. 1A, in the non-pixel portion, the liquid crystal molecules are always homogeneously aligned (0 ° Uniform alignment). On the other hand, when the rubbing direction is parallel, the liquid crystal molecules are always in the Twist orientation in the non-pixel portion (see FIG. 3C). In other words, the liquid crystal molecules arranged in the non-pixel portion always take either the Uniform orientation or the Twist orientation, and the Uniform orientation and the Twist orientation are not mixed. Therefore, nonuniformity due to the mixture of Uniform orientation and Twist orientation does not occur in the non-pixel portion. That is, it is possible to prevent a non-pixel portion from becoming a madara pattern. Therefore, it is not necessary to provide an electrode for aligning the alignment in the non-pixel portion, and the pixel portion can be enlarged and the frame can be narrowed.

  Since the master substrate 2 is subjected to the same alignment process in both the pixel portion and the non-pixel portion, the master substrate 2 is provided in the non-pixel portion of the slave substrate 1 even if the slave substrate 1 and the master substrate 2 are misaligned. The relationship between the third alignment film 6 thus formed and the first alignment film 4 provided on the master substrate 2 facing the slave substrate 1 does not change. Therefore, alignment defects do not occur.

  In addition, when a polarizing plate (not shown) is provided on the slave substrate 1 and the master substrate 2, and the liquid crystal panel (liquid crystal display element) is arranged so that the polarizing plate and the alignment axis of the liquid crystal panel form an angle of 45 °, The color tone of the liquid crystal differs between Uniform orientation and Twist orientation. In addition, the appearance of black is different between the case where the polarizing plate is parallel and the Uniform orientation, and the case where the polarizing plate is orthogonal and the Twist orientation is used (see Table 1).

  FIG. 7A is a plan view of a conventional liquid crystal display element, and FIG. 7B is a cross-sectional view taken along line E-E ′ in FIG.

  With reference to these drawings, the difference from the conventional one in the non-pixel portion of the liquid crystal display element will be briefly described. Conventionally, in the non-pixel portion, there has been no effort to make the pretilt angle at the alignment film interface on the master substrate side equal to the pretilt angle at the alignment film interface on the slave substrate side. Therefore, as shown in FIG. 7B, Uniform orientation and Twist orientation are mixed in the non-pixel portion.

  Next, the alignment state of the pixel portion will be described. Note that the alignment state of the pixel portion described below is not necessarily an essential configuration.

  In the pixel portion, the pretilt angle of the first alignment film 4 provided on the master substrate 2 side is 3 ° to 7 °, while the pretilt angle of the second alignment film 5 provided on the slave substrate 1 side is It is 0 ° or more and 1 ° or less. Therefore, the liquid crystal molecules arranged in the pixel portion can take both Uniform orientation and Twist orientation by the pulse electric field.

  A liquid crystal display element is applied with a pulse electric field in which liquid crystals on the slave substrate 1 side are vertically aligned but liquid crystal molecules on the master substrate 2 side are not vertically aligned. By this application, the liquid crystal is substantially vertically aligned except for the interface on the master substrate 2 side. Next, when the electric field is gently lowered, the vertically aligned liquid crystal molecules become anti-parallel alignment (Uniform alignment).

  On the other hand, when the electric field is suddenly lowered (that is, the electric field is reduced to 0) after applying the pulse voltage, the added chiral agent twists the liquid crystal molecules in the vertical alignment state, and the rubbing direction at the interface of the alignment film. The action to try to line up works. As a result, the liquid crystal molecules in the pixel portion have a Twist orientation twisted by 180 ° between the slave substrate 1 and the master substrate 2 as shown in FIG.

  In other words, in the pixel portion, the anchoring energy of the second alignment film 5 provided on the slave substrate 1 side is smaller than the anchoring energy of the first alignment film 4 provided on the master substrate 2 side. With this configuration, the following phenomenon occurs.

  The liquid crystal at the interface of the second alignment film 5 provided on the slave substrate 1 side tends to line up in the voltage direction with a weaker voltage. Accordingly, by vertically turning off the voltage, the vertically aligned liquid crystal molecules tend to be in the Uniform alignment or the Twist alignment while the anchoring energy of the alignment film and the twisting force of the chiral agent inside the liquid crystal molecules are balanced. When the voltage is slowly lowered with respect to the vertically aligned liquid crystal molecules, the liquid crystal molecules aligned with the voltage slowly return to the alignment direction, resulting in uniform alignment. On the other hand, when the voltage is suddenly lowered (shut off), the twisting force of the chiral agent inside the liquid crystal molecules is transmitted from the master substrate 2 side, and the Twist orientation is obtained.

  By appropriately switching and applying such a pulse electric field, as shown in FIG. 4B, an alignment state in which uniform alignment and twist alignment are mixed can be produced in the pixel portion. FIG. 4A is a plan view of the liquid crystal display element showing a state in which the pulse electric field is appropriately switched, and FIG. 4B is a cross-sectional view taken along the line D-D ′ in FIG.

  Further, according to the liquid crystal display element of the present embodiment, the pixels do not have to be in a matrix shape, and can be used for displaying Japanese characters such as a clock, a calculator, an IC card, and a character icon.

  An embodiment of the liquid crystal display element will be described. A transparent electrode ITO made of ITO (Indium Tin Oxide) is formed on the surface of a glass substrate having a thickness of 0.7 mm, and the transparent electrode ITO is formed according to a normal liquid crystal display element process. The thickness of ITO as the transparent electrode is preferably about 130 nm to 140 nm. In this way, two substrates, a master substrate 2 and a slave substrate 1, are produced.

  A method for producing the first alignment film 4 on the master substrate 2 will be described. A liquid crystal alignment film SE3510 (alignment film SE3510) manufactured by Nissan Chemical is formed with a thickness of 50 nm on the pixel portion (display area) on the substrate surface of the master substrate 2. As this forming method, a general flexographic printing method may be used, or a spin coating method or an ink jet method may be used. In this embodiment, general flexographic printing is used. After the alignment film SE3510 is printed on the master substrate 2, baking is performed at 250 ° C. for 60 minutes. Thereafter, the master substrate 2 is subjected to an orientation treatment (rubbing treatment) by rubbing at 0.5 mm per hair using a rayon rubbing cloth Yoshikawa Kako YA-18-R. By this rubbing treatment, the alignment film SE3510 is configured such that the pretilt angle of the liquid crystal molecules arranged at the interface of the alignment film SE3510 is about 5 degrees. This manufacturing method is based on a general method for forming a STN liquid crystal display element.

  Next, a method for producing the second alignment film 5 and the third alignment film 6 on the slave substrate 1 will be described. FIG. 5A is a plan view showing the slave substrate 1.

  As shown in FIG. 5 (b), the thickness of SiO is increased on the surface of the slave substrate 1 from a direction that forms an angle of 60 degrees with the normal direction of the slave substrate 1 (in the z-axis direction in the figure) to the + x direction. Diagonal vapor deposition is performed so as to be 10 nm (initial vapor deposition). In the figure, the vapor deposition direction is indicated by arrows.

  Next, as shown in FIG. 5C, SiO is continuously deposited from the direction forming an angle of 85 degrees to the normal direction of the slave substrate 1 and the + y direction so as to have a thickness of 1 nm (second deposition). In the figure, the vapor deposition direction is indicated by arrows.

  Thereby, the second alignment film 5 can be produced on the slave substrate 1.

  The pretilt angle of the second alignment film 5 disposed on the slave substrate 1 forms an angle of 1 ° or less (pretilt angle of 1 ° or less) with respect to the + y axis. Therefore, the orientation of the liquid crystal molecules arranged on the slave substrate 1 is in the + y axis direction.

  Next, an alignment film SE3510 is applied to a thickness of 50 nm using a general flexographic printing method on a portion other than the pixel portion (non-pixel portion) of the slave substrate 1 and baked at 250 ° C. Then, using a cotton rubbing cloth Yoshikawa Kako YA-25CL, alignment treatment is performed by a rubbing method at 0.5 mm per hair. This alignment film SE3510 becomes the third alignment film 6, and the pretilt angle of the liquid crystal molecules arranged at the interface of the third alignment film is about 5 degrees.

  Thereby, as shown in FIGS. 6A and 6B, the slave substrate 1 on which the second alignment film 5 and the third alignment film are formed can be manufactured.

  In this slave substrate 1, the pre-tilt angles of the alignment film (second alignment film 5) in the pixel portion, the alignment film (third alignment film 6) in the non-pixel portion, and the liquid crystal molecules arranged in these alignment films are mutually equal. Is different.

  Next, the master substrate 2 and the slave substrate 1 on which the alignment film is formed are bonded so as to have a cell thickness of 2 μm. As the spacer 7 for adjusting the cell thickness, Ube Nitto Kasei High Plessica UFN3N was used. The master substrate 2 and the slave substrate 1 were bonded together using a Mitsui Chemicals sealing agent XN21 (Seal 3).

  After the master substrate 2 and the slave substrate 1 are bonded together, a liquid crystal prepared by adding a chiral agent S811 to a Merck liquid crystal 5CB with a pitch of 8 μm is injected. Thereby, a liquid crystal panel (liquid crystal display element) can be obtained.

  The liquid crystal orientation of the liquid crystal display element thus obtained will be described separately for the pixel portion and the non-pixel portion.

  In the pixel portion, the pretilt angle of the liquid crystal molecules provided at the interface of the first alignment film 4 of the master substrate 2 is about 5 degrees, while the liquid crystal provided at the interface of the second alignment film 5 of the slave substrate 1. The pretilt angle of the molecule is 1 degree or less. Therefore, in the pixel portion, the alignment of the liquid crystal molecules becomes the Twist alignment in a state where no pulse electric field is applied.

  On the other hand, in the non-pixel portion, the pretilt angle of the liquid crystal molecules provided at the interface of the first alignment film 4 of the master substrate 2 is about 5 degrees, while it is provided at the interface of the third alignment film 6 of the slave substrate 1. The pretilt angle of the obtained liquid crystal molecules is also about 5 degrees. Therefore, in the non-pixel portion, the alignment of the liquid crystal molecules is always homogeneous alignment. Here, the reason why the orientation of the liquid crystal molecules in the non-pixel portion is always constant is that no voltage is applied to the non-pixel portion because no electrode is provided in the non-pixel portion.

  When this liquid crystal panel is sandwiched between orthogonal polarizing plates (not shown), the transmitted light is black in the pixel portion and white in the non-pixel portion. In other words, in the initial state where no pulse electric field is applied, the liquid crystal molecules are uniformly twisted in the pixel portion, and homogeneously aligned in the non-pixel portion. Here, when a pulse electric field is applied to the slave substrate 1 and the master substrate 2 to gently drop the electric field, the liquid crystal molecules in the pixel portion are in uniform alignment.

  In the present embodiment, for the sake of convenience of explanation, differences from the first embodiment will be described.

  In Example 1, the formation of the second alignment film 5 in the pixel portion of the slave substrate 1 was performed by initial vapor deposition and second vapor deposition. On the other hand, in this example, firing is performed at 150 ° C. using polysilazane manufactured by Tonen Chemical. Thereafter, Nissan Chemical SE3510 is applied to the non-pixel portion of the slave substrate 1 and the master substrate 2 and baked at 250 ° C. After that, the master substrate 2 is rubbed at 0.5 mm per hair using the rayon rubbing cloth Yoshikawa Chemical YA-18-R, while the slave substrate 1 is cotton rubbing cloth Yoshikawa Chemical YA-25-CL. . At this time, the pretilt angle of the pixel portion of the slave substrate 1 is 0.5 degrees.

  In this example, instead of polysilazane made by Tonen Chemical in Example 2, Nissan Chemical Hard Coat AT-201 was used. Others are the same as in the second embodiment.

  In this example, MOF Tl-Si made by Tokyo Ohka was used instead of polysilazane made by Tonen Chemical in Example 2. Others are the same as in the second embodiment.

  In the first embodiment, the rubbing applied to the slave substrate 1 and the master substrate 2 is made parallel. Thereby, the alignment in the initial state before applying the pulse electric field is the Twist alignment in both the pixel portion and the non-pixel portion.

Below, the comparative example with respect to a present Example is shown. Needless to say, this comparative example is not included in the technical idea of the present invention.
[Comparative Example 1]
When the horizontal alignment film SE1410 made by Nissan Chemical is used as the alignment film (second alignment film 5) of the pixel portion on the slave substrate 1 side in Example 2 above, the alignment of liquid crystal molecules is 180 ° Twist on the slave substrate 1 side. The orientation state is maintained. For this reason, it is impossible to switch between the homogeneous alignment (Uniform alignment) and the Twist alignment by applying a pulse electric field, and the bistability in the pixel portion cannot be expressed.
[Comparative Example 2]
In Example 2 above, a liquid crystal display panel (liquid crystal display element) was prepared with the same configuration except that the horizontal alignment film SE1410 manufactured by Nissan Chemical was used as the alignment film (first alignment film 4) on the master substrate 2 side. It was. However, it is impossible to switch between the homogeneous alignment (Uniform alignment) and the Twist alignment by applying the pulse electric field, and the bistability in the pixel portion cannot be expressed.
[Comparative Example 3]
In Example 2 above, the same alignment film (second alignment film 5) in the pixel portion on the master substrate 2 side as the alignment film (third alignment film 6) in the non-pixel portion on the master substrate 2 side is manufactured by Nissan Chemical Industries, Ltd. SE3510 was used. In this case, the alignment of the liquid crystal molecules on the slave substrate 1 side in the pixel portion maintains 180 ° Twist alignment. For this reason, it is impossible to switch between the homogeneous alignment (Uniform alignment) and the Twist alignment by applying a pulse electric field, and the bistability in the pixel portion cannot be expressed.
[Comparative Example 4]
In Example 2, the alignment film (second alignment film 5) was not formed on the pixel portion on the slave substrate 1 side, and the alignment process was performed by exposing the transparent electrode ITO. However, the pixel portion is a gray liquid crystal display element in which a Twist orientation and a homogeneous orientation are generated microscopically.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The liquid crystal display element of the present invention can be particularly suitably used for personal computers, mobile phones and the like.

(A) is a top view which shows the liquid crystal display element before a rubbing direction is antiparallel and applies a pulse electric field, (b) is B-B 'sectional drawing in Fig.1 (a). In addition, the line segment between the board | substrates of Fig.1 (a) shows the orientation mode of a liquid crystal molecule. (A) is a front view which shows a liquid crystal display element, (b) is A-A 'sectional drawing of Fig.2 (a). (A) is sectional drawing which shows the non-pixel part in which the rubbing directions of the master substrate side and the slave substrate side are reversed by 180 °, and (b) is the rubbing direction between the master substrate side and the slave substrate side. It is sectional drawing which shows the non-pixel part which has the same direction, (c) is sectional drawing which shows the non-pixel part from which the orientation state changed from FIG.3 (b). (A) is a top view of the liquid crystal display element which shows the state which switched the pulse electric field appropriately, FIG.4 (b) is D-D 'sectional drawing of Fig.4 (a). (A) is a top view which shows a slave substrate, (b) is a side view of the slave substrate which shows the mode of initial vapor deposition, (c) is a side view of the slave substrate which shows the mode of 2nd vapor deposition. (A) is a top view which shows the slave substrate in which the alignment film was formed, (b) is C-C 'sectional drawing of Fig.6 (a). (A) is a top view which shows the conventional liquid crystal display element, (b) is E-E 'sectional drawing of Fig.7 (a).

Explanation of symbols

1 Slave board (second board)
2 Master substrate (first substrate)
4 1st alignment film (alignment film provided in the pixel part and non-pixel part of the 1st substrate)
5 Second alignment film (alignment film provided in the pixel portion of the second substrate)
6 Third alignment film (alignment film provided in the non-pixel portion of the second substrate)

Claims (7)

In a liquid crystal display element having a first substrate and a second substrate that are opposed to each other and each provided with an electrode and an alignment film on the opposite surface side, and nematic liquid crystal is sandwiched between these substrates,
The pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided in the pixel portion and the non-pixel portion of the first substrate is equal to the pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided in the non-pixel portion of the second substrate. A liquid crystal display element characterized by being equal.   A chiral agent is injected into the nematic liquid crystal, and the pretilt angle of nematic liquid crystal molecules at the alignment film interface provided in the non-pixel portion of the second substrate is provided in the pixel portion of the second substrate. The liquid crystal display element according to claim 1, wherein the liquid crystal display element is larger than a pretilt angle of nematic liquid crystal molecules at the interface of the alignment film.   The material of the alignment film in the non-pixel portion of the second substrate and the material of the alignment film in the pixel portion and non-pixel portion of the first substrate are inorganic materials, while the material of the pixel portion of the second substrate is The liquid crystal display element according to claim 1, wherein the liquid crystal display element is an organic material.   The liquid crystal display element according to claim 3, wherein the inorganic material is SiO while the organic material is polyimide.   The pretilt angle of the alignment film in the non-pixel portion of the second substrate and the pretilt angle of the alignment film in the pixel portion and non-pixel portion of the first substrate are 3 ° or more and 7 ° or less, while the second The liquid crystal display element according to claim 1, wherein a pretilt angle of the alignment film in the pixel portion of the substrate is 1 ° or less. In a method for manufacturing a liquid crystal display element having a first substrate and a second substrate that are opposed to each other and each provided with an electrode and an alignment film on the opposite surface side, and nematic liquid crystal is sandwiched between these substrates,
The pretilt angle of the nematic liquid crystal molecules at the alignment film interface provided in the pixel portion and the non-pixel portion of the first substrate, and the pretilt angle of the nematic liquid crystal molecules at the interface of the alignment film provided in the non-pixel portion of the second substrate. And a method for manufacturing a liquid crystal display element.   A chiral agent is injected into the nematic liquid crystal, and the pretilt angle of the nematic liquid crystal molecules at the interface of the alignment film provided in the non-pixel portion of the second substrate is set to the alignment film interface provided in the pixel portion of the second substrate. The method for producing a liquid crystal display element according to claim 6, wherein the pretilt angle of the nematic liquid crystal molecules is larger.