JP2018173545A - Varnish for optical alignment film and liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a varnish for forming a photo-alignment film that can secure an adhesive force with a seal portion and can prevent or suppress the decrease in voltage holding ratio of liquid crystal and the occurrence of image sticking in a liquid crystal display device. .
A varnish for a photo-alignment film contains an alkoxysilane and a first polyamic acid compound that is a polyamic acid or a polyamic acid ester in an organic solvent. The alkoxysilane does not contain a primary amino group and a secondary amino group.
[Selection figure] None

Description

  The present invention relates to a varnish for a photoalignment film and a liquid crystal display device.

  The liquid crystal display device has two substrates (a first substrate and a second substrate) arranged to face each other. The first substrate has a first region and a second region, while the second substrate faces the first region of the first substrate, but does not face the second region of the first substrate. That is, the second region of the first substrate extends outward from the edge of the second substrate. A pixel electrode, a thin film transistor, and the like are provided in the first region of the first substrate, and a color filter, a light shielding film, and the like are provided on the second substrate. An external circuit or the like is provided in the second region of the first substrate.

  The first substrate and the second substrate define a certain cell gap therebetween, and the peripheral portion of the first region of the first substrate and the peripheral portion of the second substrate are formed in a frame shape. The liquid crystal is sealed inside the seal portion. The frame-shaped seal portion is covered with a light-shielding film provided on the second substrate. The frame-shaped seal portion and the light-shielding film define a frame region, and the frame region defines an image display region inside the frame region. ing. An alignment film for aligning liquid crystals is provided on the liquid crystal side of each substrate.

  The alignment film is generally obtained by applying a precursor organic compound solution (varnish for alignment film) dissolved in an organic solvent on a substrate, converting it to an organic film by heating, and imparting an alignment control ability to the organic film, Is formed. Conventionally, the peripheral edge of the alignment film is provided at the boundary between the image display area and the frame area.

  As a method for imparting alignment control ability to the organic film, photo-alignment treatment that imparts alignment control ability to the organic film in a non-contact manner is employed in addition to the rubbing treatment. The photo-alignment treatment is performed, for example, by irradiating the organic film with polarized ultraviolet rays in the range of 254 nm to 365 nm and cutting the molecules of the organic film in a direction parallel to the polarization direction, thereby causing the organic film to be perpendicular to the polarization direction. Add uniaxial anisotropy. The liquid crystal molecules are aligned by an alignment film imparted with uniaxial anisotropy.

  Recently, liquid crystal display devices have been required to narrow the width of the frame region, that is, to narrow the frame. Therefore, the periphery of each alignment film is located at the boundary between the image display region and the frame region. It was difficult to stop and install. As a result, the peripheral edge of each alignment film extends into the frame region, and the frame-shaped seal portion has a structure for bonding the first substrate and the second substrate through each alignment film. ing.

The alignment film (photo-alignment film) formed by the photo-alignment treatment may have a lower film strength than an unoriented organic film. When the film strength of the alignment film is lowered, the seal portion adhered to the alignment film is easily peeled off, and the reliability of the liquid crystal display device is lowered.
Therefore, for example, in Patent Document 1, an alignment film is formed from an alignment film varnish containing an amine-based silane coupling agent, and the alignment film strength is maintained even after photo-alignment treatment, and the reliability of adhesion to the seal portion is ensured. doing.

Japanese Patent Laying-Open No. 2015-82015

  However, a liquid crystal display incorporating an alignment film formed from an alignment film varnish containing an amine-based silane coupling agent is a liquid crystal display incorporating an alignment film formed from an alignment film varnish not containing an amine-based silane coupling agent. Compared with the device, the present inventors have confirmed that the display quality of the liquid crystal display device is lowered, such as a decrease in the voltage holding ratio of the liquid crystal and the occurrence of image sticking.

An object of the present invention is to provide a varnish for forming a photo-alignment film that can secure an adhesive force with a seal portion and that can prevent or suppress a decrease in voltage holding ratio of a liquid crystal of a liquid crystal display device and occurrence of seizure. Is to provide.
The other subject of this invention is providing a liquid crystal display device provided with the said photo-alignment film.

  According to the first aspect of the present invention, the organic solvent contains an alkoxysilane and a first polyamic acid-based compound that is a polyamic acid or a polyamic acid ester, and the alkoxysilane has a primary amino group and a second amino group. There is provided a varnish for a photo-alignment film characterized by not containing a secondary amino group.

  According to a second aspect of the present invention, a first substrate, a second substrate facing the first substrate, a seal portion for bonding the first substrate and the second substrate, a first substrate and a second substrate, A liquid crystal layer between the sealing portion and an alignment film in contact with the liquid crystal layer on the first substrate; the alignment film has a terminal skeleton that does not have a primary amino group and a secondary amino group; A liquid crystal display device comprising a polyimide compound having an alkoxysilane group is provided.

It is a perspective view of the liquid crystal display device concerning an embodiment. It is a figure which expands and shows the partially broken schematic cross section along the ii-ii line of FIG. It is a figure which expands and shows the partially broken schematic cross section along the iii-iii line | wire of FIG. It is a figure which shows the relationship between the applied voltage of the liquid crystal display device of an Example, and time. It is a figure which shows the test | inspection pattern of DC afterimage.

  The present inventors have examined the cause of the decrease in the voltage holding ratio of the liquid crystal and the occurrence of image sticking in the liquid crystal display device, as the photo alignment film formed from the varnish for the photo alignment film containing the amine-based silane coupling agent. It was presumed that the primary amino group or secondary amino group-derived substance of the amine silane coupling agent was eluted into the liquid crystal. As a result of further research, photo-alignment in which alkoxysilane containing no primary amino group or secondary amino group is blended with polyamic acid or polyamic acid ester, which is a polyimide precursor, instead of amine-based silane coupling agents In the alignment film formed from the varnish for film | membrane, it discovered that the fall of the voltage retention of a liquid crystal and generation | occurrence | production of image sticking could be prevented or suppressed. The alkoxysilane reacts with the polyamic acid or the polyamic acid ester during the imidation reaction of the polyamic acid or the polyamic acid ester, and is introduced as an alkoxysilane group at the end of the formed polyimide. Therefore, even when the polyamic acid or the polyamic acid ester has a primary amino group and / or a secondary amino group at the terminal, the polyimide compound as the reaction product has a primary amino group and a secondary amino group. It does not have an amino group.

  Hereinafter, some embodiments will be described with reference to the drawings. In addition, although the drawings may be schematically represented with respect to the width, thickness, shape, and the like of each part as compared with the actual mode for clarity of explanation, they are merely examples, and The interpretation is not limited. In addition, in the present specification and each drawing, components that perform the same or similar functions as those described with respect to the preceding drawings are denoted by the same reference numerals, and repeated detailed description may be omitted as appropriate. .

<Liquid crystal display device>
First, a liquid crystal display device according to an embodiment will be described with reference to FIGS. 1, 2, and 3. 1 is a perspective view of a liquid crystal display device DSP according to an embodiment, FIG. 2 is an enlarged view of a partially broken schematic cross section taken along line ii-ii in FIG. 1, and FIG. It is a figure which expands and shows the partially broken schematic cross section along the -iii line.

  In the present embodiment, the direction parallel to the short side of the liquid crystal display device DSP is the first direction X, the direction parallel to the long side of the display device DSP is the second direction Y, and the first direction X and the second direction Y A direction perpendicular to the third direction Z is taken as a third direction Z. The first direction X and the second direction Y are orthogonal to each other, but may intersect at an angle other than 90 degrees. In the present embodiment, the positive direction in the third direction Z is defined as up or upward, and the negative direction in the third direction Z is defined as down or downward.

  The liquid crystal display device DSP has a first substrate SUB1 and a second substrate SUB2 that are arranged to face each other. The first substrate SUB1 has a first region RG1 and a second region RG2. The second substrate SUB2 faces the first region RG1 of the first substrate SUB1, but does not face the second region RG2 of the first substrate SUB1. In other words, the second region RG2 of the first substrate SUB1 extends outward from the edge of the second substrate SUB2. The planar size of the first region RG1 of the first substrate SUB1 is the same as the planar size of the second substrate SUB1.

  In the first region RG1 of the first substrate SUB1, a pixel electrode, a thin film transistor, and the like are provided. The second substrate SUB2 is provided with a color filter CF, a light shielding film BM, and the like. An external circuit EXC is provided in the second region RG2 of the first substrate SUB1.

  The first substrate SUB1 and the second substrate SUB2 define a certain cell gap between them, and the peripheral portion of the first region RG1 of the first substrate SUB1 and the peripheral portion of the second substrate SUB2 are framed. It is bonded by a seal part SP formed in a shape. Liquid crystal is sealed inside the seal portion SP to form a liquid crystal layer LC. The frame-shaped seal portion SP and the light shielding film BM define a frame area NDA. The frame area NDA defines an image display area DA inside thereof. The image display area DA has, for example, a rectangular shape and includes a plurality of pixels PX arranged in a matrix of m × n (where m and n are positive integers).

  The light irradiation unit LI disposed on the opposite side of the second substrate SUB2 with respect to the first substrate SUB1 corresponds to a so-called backlight unit that illuminates the image display unit from the first substrate SUB1 side. In the second region RG2 of the first substrate SUB1, a flexible circuit board FPC1 is provided on the tip side of the external circuit EXC, and electrically connects the first substrate SUB1 and the control module CM. The control module CM is provided with a flexible circuit board FPC2 and electrically connects the control module CM and the light irradiation unit LI. The flexible circuit boards FPC1 and FPC2 transmit the drive signal of the control module CM to the first board SUB1 and the light irradiation unit LI, respectively.

  The liquid crystal display device DSP having the above configuration transmits light that selectively enters each pixel PX through the light irradiation unit LI and enters the first substrate SUB1, the liquid crystal layer LC, and the second substrate SUB2. This corresponds to a so-called transmissive liquid crystal display device having a display function.

  As well shown in FIG. 2, the first substrate SUB1 has a first base substrate S1. The first base substrate S1 is a light transmissive insulating substrate, for example, a glass substrate.

  A first insulating film IL1 is provided on the surface of the first base substrate S1 on the liquid crystal layer LC side. The first insulating film IL1 can be formed of an organic material such as an acrylic resin. A second insulating film IL2 is provided on the surface of the first insulating film IL1 on the liquid crystal layer LC side. The second insulating film IL2 can be formed of an inorganic material such as silicon oxide or silicon nitride.

  A scanning lead line SL is provided on the surface of the second insulating film IL2 on the liquid crystal layer LC side. For the scanning lead line SL, for example, a single layer metal wiring such as molybdenum (Mo), chromium (Cr), Al (aluminum), or Ti (titanium) / Al / Ti, Mo / Al / Mo, Mo / A multilayer film wiring such as InOx (indium oxide) or Cr / InOx can be used.

  An organic passivation film OP is provided on the surface of the scanning lead line SL on the liquid crystal layer LC side. The organic passivation film OP entirely covers the scanning lead line SL and covers a partially exposed surface of the second insulating film IL2. Further, the organic passivation film OP is provided with a slit ST at the end thereof. The slit ST partially exposes the surface of the second insulating film IL2. The surface of the organic passivation film OP on the liquid crystal layer LC side has an uneven shape. The organic passivation film OP can be formed of a resin such as acrylic. Since the organic passivation film OP is provided with the slit ST at the end thereof, it is possible to block moisture that has entered from the organic passivation film OP on the end side.

  A third insulating film IL3 is provided on the surface of the organic passivation film OP on the liquid crystal layer LC side so as to be along the uneven surface of the organic passivation film. The third insulating film IL3 can be formed of, for example, an inorganic material such as silicon oxide, silicon nitride, or an inorganic insulating film that is a stacked film of these. The third insulating film IL3 is an insulating film between layers (between electrodes) between a common electrode (not shown) formed in a planar shape over the entire image display area DA and a pixel electrode (not shown) having a slit. For example, the pixel electrode is formed on the surface of the third insulating film IL3 on the liquid crystal layer LC side, and the common electrode is formed between the third insulating film IL3 and the organic passivation film OP. The common electrode and the pixel electrode include, for example, a light-transmitting conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), Ag, Al, Al alloy, or the like. It can be formed of a light reflective conductive material or the like.

  A first alignment film AL1 is disposed on the surface of the first substrate SUB1 on the liquid crystal layer LC side. The first alignment film AL1 covers the third insulating film IL3 and the pixel electrode (for example, ITO).

  The second substrate SUB2 has a second base substrate S2. The second base substrate S2 is a light transmissive insulating substrate, for example, a glass substrate.

  A light shielding film BM is provided on the surface of the second base substrate S2 on the liquid crystal layer LC side. The light shielding film BM defines a frame area NDA. In the image display area DA, a color filter (not shown) is provided on the surface of the second base substrate S2 on the liquid crystal layer LC side. In the color filter, red, green, and blue filter segments are periodically arranged. These three color sub-pixels form one pixel as a set. The light shielding film BM is also provided between the filter segments. The light shielding film BM prevents color mixing between adjacent filter segments. The light shielding film BM is made of, for example, a black resin, a low reflective metal, or the like.

  An overcoat layer OC is formed on the surface of the light shielding film BM on the liquid crystal layer LC side. The overcoat layer OC covers the light shielding film BM and the color filter. The surface of the overcoat layer OC on the liquid crystal layer LC side has an uneven shape.

  A first columnar spacer PS1 is formed on the convex portion of the surface of the overcoat layer OC on the liquid crystal layer LC side. The first columnar spacer PS1 is provided so that one end thereof is in contact with the convex portion of the overcoat layer OC and the other end is in contact with the convex and concave portion on the surface on the liquid crystal layer LC side of the first alignment film AL1. The first columnar spacer PS1 has a role of defining an interval between the first substrate SUB1 and the second substrate SUB2 in the seal portion SP.

  A wall-shaped spacer WS is formed in a recess on the surface of the overcoat layer OC on the liquid crystal layer LC side. The wall-shaped spacer WS has a length that is about half that of the first columnar spacer PS1.

  On the surface of the overcoat layer OC on the liquid crystal layer LC side, a second alignment film AL2 is provided so as to follow the irregularities on the surface of the overcoat layer OC. The outer shape of the second alignment film AL2 is delimited by the wall spacer WS.

  A second columnar spacer PS2 is provided on the surface of the second alignment film AL2 on the liquid crystal layer LC side, closer to the image display area DA than the first columnar spacer PS1. The second columnar spacer PS2 is provided shorter than the first columnar spacer PS1. Therefore, one end of the second columnar spacer PS2 is in contact with the second alignment film AL2, but the other end toward the first substrate SUB1 is not in contact with the first alignment film AL1. The second columnar spacer PS2 has a role of preventing the interval between the first substrate SUB1 and the second substrate SUB2 from becoming excessively small when pressure is applied to the second substrate SUB2 from the outside.

  A seal portion SP is provided between the first alignment film AL1, the second alignment film AL2, and the overcoat layer OC. As well shown in FIG. 1, the seal part SP bonds the peripheral part of the first region RG1 of the first substrate SUB1 and the peripheral part of the second substrate SUB2 in a frame shape. The seal part SP is formed of, for example, a seal material such as an ultraviolet curable resin or a thermosetting resin, and can be formed by continuously drawing from the start point to the end point using a dispenser or the like. A bank-like spacer BS is formed at the end of the seal part SP. Since the seal part SP is provided so as to fill the uneven shape on the surface of the first alignment film AL1 and the uneven shape on the surface of the second alignment film AL2 and the overcoat surface, the adhesion surface area with the alignment film increases, The adhesive force is further increased. The liquid crystal layer LC is between the first alignment film AL1 and the second alignment film AL2.

  As illustrated in FIG. 3, the second region RG2 includes a first wiring WL1, a second wiring WL2, and a third wiring WL3 that are electrically connected to the external circuit EXC and the flexible circuit board FPC1. The first substrate SUB1 includes a first wiring WL1, a first insulating film IL1 that covers the first wiring WL1, a second wiring WL2 that is above the first wiring WL1, and a second wiring that covers the second wiring WL2. The insulating film IL2, the third wiring WL3 located above the second wiring WL2, and the third insulating film IL3 covering the third wiring WL3 are provided. The first to third insulating films IL1 to IL3 are also protective films that electrically insulate the first to third wirings WL1 to WL3 and protect these wirings. The first to third wirings WL1 to WL3 are electrically connected to the external circuit EXC and the flexible circuit board FPC1 in the second region RG2, the scanning lead line SL in the first region RG1, the signal lead line in the second region RG2, and the like. Connected to each other to transmit a drive signal. A first alignment film AL1 is provided on the third insulating film IL3, and the first alignment film AL1 is between the seal portion SP and the third insulating film IL3. An organic insulating film or the like may be further provided on the third insulating film IL3.

  In FIG. 3, the first wiring WL1 is arranged below the second wiring WL2 and the third wiring WL3. However, in another place, for example, the first wiring WL1 is connected to the second wiring WL2 or the second wiring WL2. The third wiring WL3 is replaced with the second insulating film IL2 or the third insulating film IL3. That is, the first to third wirings WL1 to WL3 are replaced with other wirings, and pass through different layers so that the external circuit EXC in the second region RG2 and the scanning lead-out line SL in the first region RG1, It is electrically connected to a signal lead line or the like in the second region RG2. By doing in this way, the 1st-3rd wiring WL1-WL3 can be efficiently provided in 2nd area | region RG2 or the frame area | region NDA narrowed by narrowing the frame. On the other hand, as shown in FIG. 3, the third wiring WL3 is easily corroded by the first alignment film AL1 because the distance to the first alignment film AL1 is short. However, since the varnish for photo-alignment films of the present invention contains an alkoxysilane described later, a crosslinked structure is formed by a coupling reaction, and the strength of the alignment film is improved. In addition, it is possible to secure an adhesive force between the alignment film and the inorganic material (SiN) film such as ITO of the pixel electrode, the third insulating film IL3, and the seal portion. As a result, a problem that the material of the alignment film permeates the insulating film IL3 and corrodes the third wiring WL3 can be suppressed.

<Varnish for photo-alignment film>
The alignment films (first alignment film AL1 and second alignment film AL2) according to the embodiment apply a varnish for a photo-alignment film on a substrate, heat it to convert it to a polyimide film, and provide alignment control ability to the polyimide film. To be provided.

  The varnish for a photoalignment film according to the first aspect of the present invention includes an alkoxysilane and a first polyamic acid compound that is a polyamic acid or a polyamic acid ester in an organic solvent, and the alkoxysilane is a primary grade. Does not contain amino groups or secondary amino groups.

<Alkoxysilane>
Since alkoxysilane is a silane coupling agent, it secures the adhesive force between the alignment film and the inorganic material (SiN) film such as ITO and third insulating film of the pixel electrode and the seal portion. That is, alkoxysilane is hydrolyzed by heating to silanol, and forms a hydrogen bond or a covalent bond with a polar substituent or functional group on the surface of the pixel electrode, the third insulating film and the seal portion, and has an adhesive force. Demonstrated. Alkoxysilanes do not contain primary and secondary amino groups as described above. Moreover, alkoxysilane is contained in the varnish for photo-alignment films at a ratio of 0.5 wt% to 2.0 wt%, for example.

In some embodiments, the alkoxysilane has an epoxy skeleton or an acid anhydride skeleton.
In some embodiments, the alkoxysilane has the following formula (1):

（式（１）中、Ｊ^１は、単結合または炭素数１〜４の２価の有機基であり、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立に、アルキル基またはアルコキシ基であり、少なくとも１つはアルコキシ基である）で表されるアルコキシシラン、または
下記式（２）：

(In the formula (1), J ¹ is a single bond or a divalent organic group having 1 to 4 carbon atoms, and R ¹ , R ² and R ³ are each independently an alkyl group or an alkoxy group, At least one is an alkoxy group), or the following formula (2):

（式（２）中、Ｋは、炭素数１〜６の３価の有機基であり、Ｊ^２は、単結合または炭素数１〜４の２価の有機基であり、Ｒ^５、Ｒ^６およびＲ^７は、それぞれ独立に、アルキル基またはアルコキシ基であり、少なくとも１つはアルコキシ基である）で表されるアルコキシシランである。

(In the formula (2), K is a trivalent organic group having 1 to 6 carbon atoms, ^{J 2} is a single bond or a divalent organic group having 1 to 4 carbon ^atoms, R 5, ^{R 6} And R ⁷ each independently represents an alkyl silane or an alkoxy group, and at least one is an alkoxy group.

In some embodiments, J ¹ is, for example, a methylene group, an ethylene group, a propylene group, a butylene group, or the like. J ² is, for example, a methylene group, an ethylene group, a propylene group, a butylene group, or the like. K is an alicyclic group such as a substituted or unsubstituted cyclobutane group. K is a benzene ring or a group containing a benzene ring, and the benzene ring may be substituted with an alkyl group or the like. K is preferably an alicyclic group.

Alkoxysilanes include trialkoxysilanes, dialkoxysilanes, and monoalkoxysilanes, but trialkoxysilanes are preferred in order to form more siloxane bonds and improve adhesion. In addition, the alkoxysilane substituent (R ¹ , R ² , R ³ , R ⁵ , R ⁶ and R ⁷ ) is preferably a substituent having a small steric hindrance in order to form a siloxane bond. The substituent of alkoxysilane is preferably, for example, a methoxy group or an ethoxy group.

  Examples of alkoxysilanes having an epoxy skeleton are 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycid Xylpropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like.

  Examples of alkoxysilanes having an acid anhydride skeleton include 3-trimethoxysilylpropyl succinic anhydride, 3-triethoxysilylpropyl succinic anhydride, 4- (3-trimethoxysilylpropyl) cyclohexane-1,2- Dicarboxylic anhydride, 4- (3-triethoxysilylpropyl) cyclohexane-1,2-dicarboxylic anhydride, 4- (3-trimethoxysilylpropyl) phthalic anhydride, 4- (3-triethoxysilylpropyl) ) Phthalic anhydride, 3-dimethylmethoxysilylpropyl succinic anhydride, 3-dimethylethoxysilylpropyl succinic anhydride, 4- (3-dimethylmethoxysilylpropyl) cyclohexane-1,2-dicarboxylic anhydride, 4 -(3-Dimethylethoxysilylpropyl) cyclohexane-1,2-dicar Phosphate anhydride, 4- (3-dimethyl-trimethoxysilylpropyl) phthalic acid anhydride or 4- (3-dimethyl-ethoxysilylpropyl) phthalic anhydride and the like.

<First polyamic acid compound>
In some embodiments, the first polyamic acid-based compound has the following formula (3):

（式（３）中、Ｘは、環式基であり、Ｒ^８およびＲ^９は、それぞれ独立に、−ＣＯＯＨまたは−ＣＯＯＲ（ここで、Ｒは、アルキル基である）であり、Ｙ^１は、有機基である）で表される構造単位を有する。

(In Formula (3), X is a cyclic group, R ⁸ and R ⁹ are each independently —COOH or —COOR (where R is an alkyl group), and Y ¹ is , Which is an organic group).

  In one embodiment, X is an alicyclic group, such as a substituted or unsubstituted cyclobutane group. In another embodiment, X is a benzene ring or a group containing a benzene ring, and the benzene ring may be substituted with an alkyl group or the like. X is preferably an alicyclic group.

  In some embodiments, the first polyamic acid-based compound has a diamine skeleton represented by the following formula (4).

式（４）において、Ｌは、有機基であり、例えば環式基を含む基である。いくつかの実施形態において、Ｌは、Ａｒ^０またはＡｒ^１−Ｚ−Ａｒ^２であり、ここで、Ａｒ^０は、芳香族基であり、Ａｒ^１およびＡｒ^２は、それぞれ独立に、芳香族基であり、Ｚは、第一級アミノ基および第二級アミノ基を含有しない有機基である。Ａｒ^０、Ａｒ^１またはＡｒ^２によって表される芳香族基の例は、ベンゼン環またはベンゼン環を含む基である。Ｚは、例えば、酸素、窒素、硫黄、炭素および水素、またはそれら２つ以上の組合せから構成される。Ｚは、ヒドロキシル基、チオール基および第三級を除くアミノ基（−ＮＨまたは＞ＮＨ）を有しない。

In formula (4), L is an organic group, for example, a group containing a cyclic group. In some embodiments, L is Ar ⁰ or Ar ¹ -Z-Ar ² , wherein Ar ⁰ is an aromatic group, and Ar ¹ and Ar ² are each independently an aromatic group. And Z is an organic group that does not contain a primary amino group and a secondary amino group. Examples of the aromatic group represented by Ar ⁰ , Ar ¹ or Ar ² are a benzene ring or a group containing a benzene ring. Z is composed of, for example, oxygen, nitrogen, sulfur, carbon and hydrogen, or a combination of two or more thereof. Z does not have an amino group (—NH or> NH) except a hydroxyl group, a thiol group and a tertiary group.

<Terminal skeleton of the first polyamic acid compound>
In some embodiments, each terminal skeleton of the first polyamic acid-based compound has the following formula (5):

（式（５）中、Ｊ^１は、式（１）に関して定義した通りであり、ｍは、１または２の整数であり、Ｒ^１、Ｒ^２およびＲ^３は、式（１）に関して定義した通りである）で表されるか、または下記式（６）：

(In formula (5), J ¹ is as defined for formula (1), m is an integer of 1 or 2, and R ¹ , R ² and R ³ are defined for formula (1). Or the following formula (6):

（式（６）中、Ｋは、式（２）に関して定義した通りであり、Ｊ^２は、式（２）に関して定義した通りであり、Ｒ^４は、−ＣＯＯＨまたは−ＣＯＯＲ（ここで、Ｒは、アルキル基である）であり、Ｒ^５、Ｒ^６およびＲ^７は、式（２）に関して定義した通りである）で表される。

(In formula (6), K is as defined for formula (2), J ² is as defined for formula (2), and R ⁴ is —COOH or —COOR (where R Is an alkyl group), and R ⁵ , R ⁶ and R ⁷ are as defined for formula (2).

  The terminal skeleton of the first polyamic acid compound such as the above formulas (5) and (6) is a polyamic acid or polyamic acid ester having a primary amino group and / or a secondary amino group at the terminal. It can be formed by reacting such a first polyamic acid compound with an alkoxysilane such as the above formulas (1) and (2).

  In some embodiments, the first polyamic acid-based compound has an alkoxysilane represented by the above formula (1) or (2) at the molecular end.

  In some embodiments, the terminal skeleton of the first polyamic acid-based compound has an imide skeleton, an amide skeleton, a urea skeleton, a tertiary amino skeleton, an azo bond, or a carboxyl group.

  In some embodiments, each terminal skeleton of the first polyamic acid-based compound has the following formula (7):

（式（７）中、Ｙ^２は、Ｈ、Ｓまたは有機基であり、かつＹ^３は、脂肪族基または芳香族基であり、またはＹ^２およびＹ^３は、互いに結合して環式基（例えばイミド）を形成している）で表されるか、下記式（８）：

(In Formula (7), Y ² is H, S or an organic group, and Y ³ is an aliphatic group or an aromatic group, or Y ² and Y ³ are bonded to each other to form a cyclic group. (Forms an imide, for example) or the following formula (8):

（式（８）中、Ｙ^４は、有機基である）で表されるか、または下記式（９）：

(In formula (8), Y ⁴ is an organic group) or the following formula (9):

（式（９）中、Ｘは、式（３）に関して定義した通りであり、Ｒ^１０およびＲ^１１は、互いに独立に、水素またはアルキル基である）で表される。

(In formula (9), X is as defined for formula (3), and R ¹⁰ and R ¹¹ are each independently hydrogen or an alkyl group).

<Organic solvent>
In some embodiments, the varnish for a photo-alignment film includes N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N as an organic solvent for dissolving or dispersing the polyamic acid-based compound. -Methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, ethylamyl Ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, and 4-hydroxy-4-methyl-2-pentanone You can use.

<Synthesis of First Polyamic Acid Compound>
The polyamic acid can be produced by reacting tetracarboxylic dianhydride and diamine by a conventional method.
Tetracarboxylic dianhydride can be represented by the following formula (A).

式（Ａ）において、Ｘは、式（３）に関して定義した通りである。
Ｘとして置換または無置換のシクロブタン基を有するテトラカルボン酸二無水物は、下記式（Ｂ）で示すことができる。

In formula (A), X is as defined for formula (3).
A tetracarboxylic dianhydride having a substituted or unsubstituted cyclobutane group as X can be represented by the following formula (B).

式（Ｂ）において、各Ｒ^ｂは、それぞれ独立に、水素またはアルキル基である。アルキル基の例は、１個〜６個の炭素原子を有するアルキル基である。アルキル基としては、メチル基が特に好ましい。

In the formula (B), each R ^b is independently hydrogen or an alkyl group. Examples of alkyl groups are alkyl groups having 1 to 6 carbon atoms. As the alkyl group, a methyl group is particularly preferable.

  An example of a tetracarboxylic dianhydride having a benzene ring as X is pyromellitic acid.

  As the tetracarboxylic dianhydride, a tetracarboxylic dianhydride represented by the formula (B) is preferable.

  The diamine to be reacted with the tetracarboxylic dianhydride is an organic compound having two primary amino groups. Diamine can be represented by the following formula (C).

式（Ｃ）において、Ｌは、式（４）に関して定義した通りである。
式（Ｃ）で示されるジアミンには、脂環式ジアミン、複素環式ジアミン、脂肪族ジアミンおよび芳香族ジアミンが含まれる。代表例は芳香族ジアミンである。

In formula (C), L is as defined for formula (4).
Diamines represented by formula (C) include alicyclic diamines, heterocyclic diamines, aliphatic diamines and aromatic diamines. A typical example is an aromatic diamine.

  Examples of aromatic diamines are o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino-2. -Methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5-dichlorobenzene, 4,4'- Diamino-1,2-diphenylethane, 4,4′-diamino-2,2′-dimethylbibenzyl, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4, , 4'-diamino-3,3'-dimethyldiphenylmethane, 2,2'-diaminostilbene, 4,4'-diaminostil 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 4,4′- Diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,5-bis (4- Aminophenoxy) benzoic acid, 4,4′-bis (4-aminophenoxy) bibenzyl, 2,2-bis [(4-aminophenoxy) methyl] propane, 2,2-bis [4- (4-aminophenoxy) Phenyl] hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4 (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,1-bis (4-aminophenyl) cyclohexane, α, α′-bis (4-aminophenyl)- 1,4-diisopropylbenzene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4′-diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6-diaminopyrene, 1,8-diaminopyrene, 2,7-diaminofluorene, 1,3-bis (4-aminophenyl) Tetramethyldisiloxane, benzidine, 2,2'-dimethylbenzidine, 1,2-bis (4-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,4-bis (4-amino) Phenyl) butane, 1,5-bis (4-aminophenyl) pentane, 1,6-bis (4-aminophenyl) hexane, 1,7-bis (4-aminophenyl) heptane, 1,8-bis (4 -Aminophenyl) octane, 1,9-bis (4-aminophenyl) nonane, 1,10-bis (4-aminophenyl) decane, 1,3-bis (4-aminophenoxy) propane, 1,4-bis (4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,7-bis (4-aminophenyl) Enoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane, di (4-aminophenyl) Propane-1,3-dioate, di (4-aminophenyl) butane-1,4-dioate, di (4-aminophenyl) pentane-1,5-dioate, di (4-aminophenyl) hexane-1,6 -Dioate, di (4-aminophenyl) heptane-1,7-dioate, di (4-aminophenyl) octane-1,8-dioate, di (4-aminophenyl) nonane-1,9-dioate, di ( 4-aminophenyl) decane-1,10-dioate, 1,3-bis [4- (4-aminophenoxy) phenoxy] propane, 1,4-bis [4- 4-aminophenoxy) phenoxy] butane, 1,5-bis [4- (4-aminophenoxy) phenoxy] pentane, 1,6-bis [4- (4-aminophenoxy) phenoxy] hexane, 1,7-bis [4- (4-aminophenoxy) phenoxy] heptane, 1,8-bis [4- (4-aminophenoxy) phenoxy] octane, 1,9-bis [4- (4-aminophenoxy) phenoxy] nonane, 1 , 10-bis [4- (4-aminophenoxy) phenoxy] decane and the like. Furthermore, the example of aromatic diamine is shown below (in the following examples, n is an integer of 1-10).

上記芳香族ジアミンは、下記式（Ｄ）または式（Ｅ）で表すことができる。

The aromatic diamine can be represented by the following formula (D) or formula (E).

式（Ｄ）および（Ｅ）において、Ａｒ^０、Ａｒ^１およびＡｒ^２、並びにＺは、式（３）に関して定義した通りである。式（Ｄ）に示されるアミンによって生成された配向膜は光配向性が高く、第２ポリアミド酸系化合物の生成に用いると好ましい。また式（Ｅ）で示されるアミンによって生成された配向膜は、チオール基およびヒドロキシル基がないため水素結合の影響が小さく高抵抗になりやすい。また、このアミンは、Ｚ内に第三級を除くアミノ基（−ＮＨまたは＞ＮＨ）を有していないため、第１ポリアミド酸系化合物の生成に用いることが好ましい。なお、アミド結合は、第二級アミノ基とは化学性質が異なるため区別されている。つまり、Ｚ内にアミド結合を有するアミンは除かれていない。

In formulas (D) and (E), Ar ⁰ , Ar ¹ and Ar ² , and Z are as defined for formula (3). The alignment film formed by the amine represented by the formula (D) has high photoalignment, and is preferably used for generating the second polyamic acid compound. In addition, since the alignment film produced by the amine represented by the formula (E) does not have a thiol group and a hydroxyl group, the influence of hydrogen bonding is small and the resistance tends to be high. Moreover, since this amine does not have an amino group (-NH or> NH) excluding tertiary in Z, it is preferably used for the production of the first polyamic acid compound. The amide bond is distinguished from the secondary amino group because it has different chemical properties. That is, amines having an amide bond in Z are not excluded.

  In the reaction of tetracarboxylic dianhydride and diamine, if diamine is used in a slight excess (for example, 1.1 to 1.5 times the molar amount of tetracarboxylic dianhydride) than tetracarboxylic dianhydride, In other words, a polyamic acid compound having a primary amino group at both ends, in other words, a polyamic acid compound having a primary amine as a terminal skeleton is formed.

  The polyamic acid ester can be produced by reacting, for example, N, N-dimethylformamide dialkyl acetal with the polyamic acid described above. Alternatively, the polyamic acid ester can also be produced by the method described in JP 2000-273172 A.

  A first polyamic acid-based compound can be obtained by chemically modifying both terminal primary amino groups of a polyamic acid or polyamic acid ester having primary amino groups at both ends. This chemical modification is the sealing of the primary amino group.

  As a method for chemically modifying the terminal primary amino group, there is amidation. As a sealing agent (amidating agent) for this purpose, a compound having one halogenated carbonyl group per molecule, that is, a monofunctional acid halide can be used. Halides include chloride, bromide, and fluoride. Examples of monofunctional acid halides include benzoyl chloride, acetyl chloride, propionyl chloride, acryloyl chloride, methacryloyl chloride, tosyl chloride and the like.

  Moreover, you may use the compound which has one acid anhydride in 1 molecule, ie, a monofunctional acid anhydride, as another sealing material to amidate. Examples of monofunctional anhydrides are phthalic anhydride, maleic anhydride, succinic anhydride, itaconic anhydride, trimellitic anhydride, 1,2,4-cyclohexanetricarboxylic acid-1,2-anhydride Products, cyclohexene-1,2-dicarboxylic anhydride, and the like. When the terminal primary amino group is chemically modified with these compounds, the terminal portion of the alignment film varnish is usually in the state of a polyamic acid compound. Thereafter, the compound is imidized when formed into a film and fired.

  Further, as another method for amidation, an amic acid ester may be used. In order to convert the terminal to an amic acid ester, a known aromatic compound having an amine reactive group such as a carboxyl group or an acid halide (halogenated carboxyl group) and an ester skeleton may be used as a sealant. Moreover, the compound which made the terminal the state of amic acid by the above-mentioned method can also be made into an amic acid ester by making N, N-dimethylformamide dialkyl acetal react, for example. When the terminal primary amino group is chemically modified with these compounds, the terminal portion of the alignment film varnish is usually in a polyamic acid ester state. After that, the terminal portion is imidized when the film is formed and fired.

  Moreover, the state by which the terminal was imidated may be sufficient as the varnish for alignment films. In order to obtain an imidized end, a compound sealed with amide acid or amide acid ester may be heated to cause dehydration condensation.

  In addition, chemical modification by a method other than amidation or imidation may be used. For example, azotization, urea formation, or tertiary amination may be used.

  Examples of the azotization include diazonium salt-based diazo coupling agents as examples of sealing agents (azotizing agents). For urea formation, an isocyanate-based material can be used as a sealant. Examples of isocyanate are phenyl isocyanate, naphthyl isocyanate, and the like. In the tertiary amination, a compound having a halogen group (especially chlorine) or a hydroxyl group can be used as a sealing agent (tertiary amination agent). In addition, you may azotize, urea, and tertiary amination with materials other than the sealing agent described above.

  In another embodiment, the polyamic acid-based compound having a terminal skeleton that does not contain a primary amino group has more tetracarboxylic dianhydride than diamine in the reaction of the tetracarboxylic dianhydride and the diamine ( For example, it can be produced by using 1.1 to 1.5 times the molar amount of diamine). By this reaction, a polyamic acid compound having carboxyl groups at both ends is produced.

  As is clear from the above description, the first polyamic acid-based compound having groups other than the primary amino group at both ends can have an acid skeleton represented by the following formula (10).

式（１０）において、Ｘは、式（３）に関して定義した通りであ

In formula (10), X is as defined for formula (3).

  The acid skeleton represented by the formula (10) includes an acid skeleton represented by the following formula (10-1) and the following formula (10-2).

式（１０−１）において、Ｒ^aは、アルキル基（例えば、１〜６個の炭素原子を有するアルキル基）であり、Ｒ^bは、式（Ｂ）に関して定義したとおり、水素またはアルキル基である。

In Formula (10-1), R ^a is an alkyl group (eg, an alkyl group having 1 to 6 carbon atoms), and R ^b is hydrogen or an alkyl group as defined for Formula (B). is there.

The amine skeleton is as described above.
Further, as apparent from the above description, the first polyamic acid-based compound may have a structural unit (repeating unit) represented by the formula (3), and the terminal skeleton thereof is an imide skeleton, an amide skeleton, or a urea skeleton. A tertiary amino skeleton, an azo bond or a carboxyl group. The structural unit represented by the formula (3) includes a structural unit represented by the following formula (3-1) or the following formula (3-2).

式（３−１）および式（３−２）において、Ａｒは、前記式（４）に関して定義したＡｒ⁰、またはＡｒ¹-Ｚ−Ａｒ²である。式（３−１）において、Ｒ^aおよびＲ^bは、前記式（１０−１）に関して定義したとおりである。Ｚは式（４）で定義した通りである。

In Formula (3-1) and Formula (3-2), Ar is Ar ⁰ or Ar ¹ -Z-Ar ² defined with respect to Formula (4). In formula (3-1), R ^a and R ^b are as defined for formula (10-1). Z is as defined in Equation (4).

<Varnish for photo-alignment film further containing second polyamic acid compound>
In another embodiment, the varnish for a photo-alignment film further includes a second polyamic acid-based compound that is a polyamic acid or a polyamic acid ester in addition to the first polyamic acid-based compound as the polyamic acid-based compound. In this case, the first polyamic acid compound has a higher polarity (large surface energy) than the second polyamic acid compound. Therefore, when the first polyamic acid-based compound and the second polyamic acid-based compound coexist, they are phase-separated. In this case, the first polyamic acid compound is more compatible with an organic passivation film using an inorganic material film such as ITO or silicon oxide or silicon nitride, or an organic resin, which forms a pixel electrode in a liquid crystal display device. Since it is high, a 1st polyamic-acid type compound becomes a lower layer. Usually, when a polyamic acid ester and a polyamic acid coexist, the polyamic acid ester forms an upper layer and the polyamic acid forms a lower layer. Further, when two kinds of polyamic acids coexist, oxygen or fluorine is present in the diamine skeleton of one polyamic acid, and neither oxygen nor fluorine is present in the diamine skeleton of the other polyamic acid. The polyamic acid forms a lower layer, and the other polyamic acid forms an upper layer. In addition, even when oxygen or fluorine is present in the other polyamic acid, when the amount is less than the amount of oxygen or fluorine in the diamine skeleton of the one polyamic acid, the one polyamic acid forms a lower layer. The other polyamic acid forms the upper layer.

  Needless to say, when the alignment film is a single layer, the first polyamic acid compound is used as the polyamic acid compound.

  The second polyamic acid compound can be selected from the compounds listed as the first polyamic acid compound. Also, the polyamic acid-based compound before sealing the primary amino groups at both ends for producing the first polyamic acid-based compound, that is, the polyamic acid or the polyamic acid ester having primary amino groups at both ends is used. You can also choose from. However, like the first polyamic acid compound, the second polyamic acid compound preferably does not have a primary amino group at both ends. Regardless of whether the alignment film has a single layer or a two-layer structure, both the first polyamic acid-based compound and the second polyamic acid-based compound have secondary amino groups (the first forming an amide). It preferably has no secondary amino group).

  As is clear from the above description, regarding the alignment film having a two-layer structure, the lower layer refers to a layer that directly contacts an application target (for example, an ITO film, an inorganic material film, or an organic passivation film), and the upper layer refers to the lower layer. The layer that touches.

  In the case of an alignment film having a two-layer structure, the first polyamic acid compound having high polarity is included in the lower layer and is in contact with the pixel electrode. In order to suppress image sticking, it is necessary to avoid charge accumulation due to photocharge of the lower layer film, so at least the first polyamic acid compound contained in the lower layer film does not have a primary amino group at both ends. It is preferable.

<Alignment film>
The varnish of the present invention is imidized by applying it to an application target and heating at a temperature of about 200 ° C. More specifically, in the case of a varnish containing only the first polyamic acid compound as the polyamic acid compound, the first polyamic acid compound is imidized. In the case of a varnish containing a first polyamic acid compound and a second polyamic acid compound as the polyamic acid compound, the first polyamic acid compound and the second polyamic acid compound are phase-separated into two layers after coating and heated. Both imidize.

A photo-alignment process is performed on the film after imidation to provide an alignment film. The photo-alignment treatment can be performed by irradiating the film with short wavelength ultraviolet light having a wavelength of 254 nm or 365 nm.
In some embodiments, the polyimide compound has the following formula (11):

（式（１１）中、Ｊ^１、並びにＲ^１、Ｒ^２およびＲ^３は、式（１）に関して定義した通りである）で表される末端骨格、
下記式（１２）

(In formula (11), J ¹ and R ¹ , R ² and R ³ are as defined for formula (1)),
Following formula (12)

（式（１２）中、Ｊ^１、並びにＲ^１、Ｒ^２およびＲ^３は、式（１）に関して定義した通りである）で表される末端骨格、
下記式（１３）：

(In formula (12), J ¹ and R ¹ , R ² and R ³ are as defined in relation to formula (1)),
Following formula (13):

（式（１３）中、Ｊ^１、並びにＲ^１、Ｒ^２およびＲ^３は、式（１）に関して定義した通りである）で表される末端骨格、または
下記式（１４）：

(In formula (13), J ¹ and R ¹ , R ² and R ³ are as defined for formula (1)), or the following formula (14):

（式（１４）中、Ｋ、Ｊ^２並びにＲ^５、Ｒ^６およびＲ^７は、式（２）に関して定義した通りである）で表される末端骨格を有する。

(In the formula (14), K, J ^{2 and} R ⁵ , R ⁶ and R ⁷ are as defined in relation to the formula (2)).

  The polyimide compound having a terminal skeleton as in the above formulas (11) to (14) is heated to imidize the first polyamic acid compound having a terminal skeleton as in the above formulas (4) and (5). Can be formed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, the synthesis example of a polyamic-acid type compound is described first.

Synthesis Example of Polyamic Acid Compound 1,3-Dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride 100 mol part NMP solution and p-phenylenediamine 90 mol part NMP solution were mixed. The reaction was carried out at room temperature for 8 hours to produce polyamic acid. Unreacted monomers and low molecular weight components were removed to obtain a polyamic acid solution having a solid concentration of 15% by mass.

  Table 1 below shows the acid skeleton, diamine skeleton, and terminal skeleton of the polyamic acid compound synthesized in the synthesis example described above. In Table 1, the “*” mark attached to the acid skeleton indicates the binding site with the diamine skeleton, and the “*” mark attached to the diamine skeleton indicates the binding site with the acid skeleton, In the case where the terminal skeleton has an amide, the “*” mark indicates the binding site with the acid skeleton, and when the terminal skeleton has a carboxyl group, the binding site with the diamine skeleton.

Examples 1 to 3 and Comparative Examples 1 and 2
To the polyamic acid compound of Table 1 above, alkoxysilane as shown in Table 2 below was added (may not be added), and each coating solution was prepared by stirring uniformly. Each coating liquid is applied to the region where the first alignment film AL1 on the first substrate SUB1 and the second alignment film AL2 on the second substrate SUB2 of the liquid crystal display device having the structure shown in FIGS. Imidization was performed by heating to 200 ° C. The imidation ratio was 80% in all cases. Each imidized film was subjected to photo-alignment treatment using short-wavelength ultraviolet light. After each alignment film is cleaned, the liquid crystal display device having the structure shown in FIG. 1 is formed by a conventional method using the first substrate SUB1 formed with the first alignment film AL1 and the second substrate SUB2 formed with the second alignment film AL2. Was made. As a liquid crystal, a nematic liquid crystal material having a negative dielectric anisotropy Δε and a value of −4.1 (1 kHz, 20 ° C.) and a refractive index anisotropy Δn of 0.0821 (wavelength 590 nm, 20 ° C.). (Merck MLC-2039) was used.

  First, the produced liquid crystal display devices of Comparative Example 1 and Comparative Example 2 are driven under the conditions of a temperature of 60 ° C., a frame frequency of 1 Hz, and an applied voltage of 5 V, and an amine system for the voltage holding ratio of the liquid crystal contained in the liquid crystal display device The influence of a silane coupling agent (3-aminopropyltrimethoxysilane) was examined. The result is shown in FIG.

  As is clear from FIG. 4, Comparative Example 2 ((ii) in FIG. 4) containing an amine-based silane coupling agent was compared with Comparative Example 1 ((i) in FIG. 4) containing no alkoxysilane. Thus, it can be seen that the voltage one second after the voltage application is lowered, that is, the voltage holding ratio is lowered.

Next, on the liquid crystal display devices of Examples 1 to 3 and Comparative Examples 1 and 2, the checker flag pattern of white and black (shown by hatching in the figure) shown in FIG. 5 was displayed at 60 ° C. for 1 hour. Each checker pattern was a square with a side of 5 mm. White has the maximum luminance (256/256 gradations), and black has the minimum luminance (0/256 gradations). Thereafter, when gray display with 31/256 gradations was made on the entire screen, a phenomenon (burn-in) in which the luminance was different between the white display portion and the black display portion during 1 hour display was observed. Brightness change rate of both displays:
{(Ab) / b} × 100
(Where a is the luminance of the white display portion and b is the luminance of the black display portion) was defined as the afterimage intensity. If this value is 1% or more, it is recognized as an afterimage by human eyes.

The presence or absence of image sticking in the gray display after the checker flag pattern was continuously lit at 60 ° C. for 1 hour was visually observed and evaluated in the following three stages.
A: Seizure was not visually recognized in gray display.
B: Although seizure was visually recognized in gray display, it was within an allowable range (seizure barely visible when viewed obliquely).
C: Image sticking was visually recognized in gray display.

Moreover, each coating liquid of the said Table 2 was apply | coated on the said SiN of the glass substrate provided with a silicon nitride film (SiN), and it heated at 200 degreeC, and imidated. The imidation ratio was 80% in all cases. Each imidized film was subjected to photo-alignment treatment using short-wavelength ultraviolet light. After each alignment film was washed, substrates having the same structure were bonded together after a sealant was bonded thereto, and the adhesion between the substrates was evaluated in the following three stages.
A: The substrate could not be peeled off by hand.
B: The substrate could be peeled off by hand.
C: The substrate could be easily peeled off by hand.
The results are also shown in Table 2.

表２の結果から明らかなように、実施例１〜３の光配向膜用ワニスを含む配向膜を備える液晶表示装置は、焼付きが抑制または防止され、シール部との接着力を確保できる。

As is apparent from the results in Table 2, the liquid crystal display device including the alignment film containing the varnish for optical alignment film of Examples 1 to 3 can suppress or prevent seizure and secure an adhesive force with the seal portion.

  In the above embodiment, the transmissive liquid crystal display device has been described as an example of the liquid crystal display device. However, the liquid crystal display device DSP, for example, selectively reflects external light incident from the outside on each pixel PX. A so-called transflective liquid crystal display device having a reflective display function for displaying an image may also be used. In the transflective liquid crystal display device, a front light unit may be disposed on the viewer side of the liquid crystal display panel PNL as a light source.

  In addition, as an example of the liquid crystal display device, a liquid crystal display device in a mode mainly using a lateral electric field such as an IPS (In-Plane Switching) mode and an FFS (Fringe Field Switching) mode has been described. For example, the present invention can also be applied to a liquid crystal display device that mainly uses a vertical electric field, such as a TN (Twisted Nematic) mode, an OCB (Optically Compensated Bend) mode, or a VA (Vertical Aligned) mode.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DSP ... Liquid crystal display device SUB1 ... First substrate SUB2 ... Second substrate RG1 ... First region RG2 ... Second region CF ... Color filter BM ... Shading film EXC ... External circuit SP ... Sealing part LC ... Liquid crystal layer NDA ... Frame region DA ... Image display area PX ... Pixel FPC1, FPC2 ... Flexible circuit board CM ... Control module LI ... Light irradiation part S1 ... First base substrate IL1 ... First insulating film IL2 ... Second insulating film IL3 ... Third insulating film SL ... Scanning Lead line OP ... Organic passivation film ST ... Slit AL1 ... First alignment film S2 ... Second base substrate OC ... Overcoat layer PS1, PS2 ... Column spacer WS ... Wall spacer AL2 ... Second alignment film WL1 ... First wiring WL2 ... second wiring WL3 ... third wiring

Claims (12)

In an organic solvent, an alkoxysilane and a first polyamic acid compound that is a polyamic acid or a polyamic acid ester are included,
The varnish for a photo-alignment film, wherein the alkoxysilane does not contain a primary amino group and a secondary amino group.   The varnish for a photoalignment film according to claim 1, wherein the alkoxysilane has an epoxy skeleton or an acid anhydride skeleton. The first polyamic acid-based compound has the following formula (1):

(In the formula (1), J ¹ is a single bond or a divalent organic group having 1 to 4 carbon atoms, m is an integer of 1 or 2, and R ¹ , R ² and R ³ are respectively Independently an alkyl group or an alkoxy group, and at least one is an alkoxy group), or a terminal skeleton represented by the following formula (2):

(In the formula (2), K is a trivalent organic group having 1 to 6 carbon atoms, ^{J 2} is a single bond or a divalent organic group having 1 to 4 carbon atoms, ^{R 4} is - COOH or —COOR (wherein R is an alkyl group), R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group or an alkoxy group, and at least one is an alkoxy group) The varnish for a photo-alignment film according to claim 1, which has a terminal skeleton represented by The alkoxysilane has the following formula (3):

(In the formula (3), K is a trivalent organic group having 1 to 6 carbon atoms, ^{J 2} is a single bond or a divalent organic group having 1 to 4 carbon ^atoms, R 5, ^{R 6} 4 and R ⁷ are each independently an alkyl group or an alkoxy group, and at least one is an alkoxy group). Varnish for photo-alignment film. The first polyamic acid-based compound has the following formula (4):

(In Formula (4), X is a cyclic group, R ⁸ and R ⁹ are each independently —COOH or —COOR (where R is an alkyl group), and Y ¹ is The varnish for a photo-alignment film according to claim 1, wherein the varnish for a photo-alignment film has a structural unit represented by: The first polyamic acid-based compound has the following formula (5):

(In the formula (5), L is Ar ⁰ or an ^{Ar 1 -Z-Ar 2,,} Ar 0, Ar 1 and Ar ² each independently, an aromatic group, Z is a primary 6. The varnish for a photoalignment film according to claim 1, which has a diamine skeleton represented by an organic group containing no amino group and secondary amino group.   The Z is composed of oxygen, nitrogen, sulfur, carbon, hydrogen or a combination of two or more thereof, and the Z has an amino group (—NH or> NH) excluding a hydroxyl group, a thiol group and a tertiary group. The varnish for a photo-alignment film according to claim 6, wherein the varnish is not used.   The second polyamic acid compound which is a polyamic acid or a polyamic acid ester is further included, and the first polyamic acid compound has a higher polarity than the second polyamic acid compound. Item 8. The varnish for a photoalignment film according to any one of Items 7 to 7. A first substrate;
A second substrate facing the first substrate;
A seal portion for bonding the first substrate and the second substrate;
A liquid crystal layer between the first substrate, the second substrate, and the seal portion;
An alignment film on the first substrate and in contact with the liquid crystal layer;
The alignment film includes a polyimide compound whose terminal skeleton does not have a primary amino group and a secondary amino group but has an alkoxysilane group. The polyimide compound has the following formula (6):

(In the formula (6), ^{J 1} is a single bond or a divalent organic group having 1 to 4 carbon ^atoms, R 1, ^{R 2} and ^{R 3} are each independently an alkyl group or an alkoxy group, At least one is an alkoxy group)
Following formula (7):

(In the formula (7), ^{J 1} is a single bond or a divalent organic group having 1 to 4 carbon ^atoms, R 1, ^{R 2} and ^{R 3} are each independently an alkyl group or an alkoxy group, At least one is an alkoxy group)
Following formula (8):

(In the formula (8), ^{J 1} is a single bond or a divalent organic group having 1 to 4 carbon ^atoms, R 1, ^{R 2} and ^{R 3} are each independently an alkyl group or an alkoxy group, At least one is an alkoxy group), or the following formula (9):

(In the formula (9), K is a trivalent organic group having 1 to 6 carbon atoms, ^{J 2} is a single bond or a divalent organic group having 1 to 4 carbon ^atoms, R 5, ^{R 6} And R ⁷ each independently has an end group represented by an alkyl group or an alkoxy group, and at least one is an alkoxy group.   11. The liquid crystal display according to claim 9, wherein the first substrate includes an insulating film on the liquid crystal layer side, and the alignment film is provided between the seal portion and the insulating film. apparatus.   The first substrate includes a first wiring, a first insulating film that covers the first wiring, a second wiring that is above the first wiring, a second insulating film that covers the second wiring, A third wiring on the upper side of the second wiring; a third insulating film covering the third wiring; and the alignment film between the seal portion and the third insulating film. The liquid crystal display device according to any one of claims 9 to 11.

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