WO2011108642A1

WO2011108642A1 - Liquid crystal display element and manufacturing method thereof

Info

Publication number: WO2011108642A1
Application number: PCT/JP2011/054908
Authority: WO
Inventors: 丞治河村; 雅夫浦山
Original assignee: Dic株式会社; シャープ株式会社
Priority date: 2010-03-04
Filing date: 2011-03-03
Publication date: 2011-09-09
Also published as: JP2013101163A

Abstract

Disclosed is a liquid crystal display element comprising a pair of mutually opposed substrates (100, 200); a seal material (301) disposed between the substrates; and a liquid crystal layer (303) sealed in a sealed region surrounded by the seal member (301). Protrusions (304) are disposed upon the substrate surfaces whereat the seal material (301) makes contact.

Description

Liquid crystal display element and manufacturing method thereof

The present invention relates to a liquid crystal display element.

In general, a liquid crystal panel (LCD) has a back substrate having a thin film transistor (TFT), a pixel electrode, an alignment film, and the like opposed to a front substrate having a color filter, an electrode, an alignment film, etc. It is configured to enclose. Further, a sealing material is generally used for the purpose of bonding the two substrates.
Glass is generally used as the substrate. Recently, the glass substrate has been made thinner for the purpose of weight reduction, and the stress due to the deformation of the glass tends to increase due to the thinner film. For this reason, the seal portion is required to have flexibility to withstand such increasing stress.
On the other hand, an attempt to use a plastic film such as a polyimide film instead of a conventional glass substrate as a substrate for the purpose of weight reduction or flexibility has been studied. In particular, recently, for the purpose of improving production efficiency, research on LCD production methods by a roll-to-roll method using a plastic film has been advanced. When such a flexible substrate is used, the seal portion is required to have high adhesion and flexibility that can follow the bending of the substrate.

Conventionally, as a sealing material for a liquid crystal panel, a thermosetting sealing material mainly composed of an epoxy thermosetting resin has been mainly used. However, such a sealing agent requires a long time when the substrates are bonded together to cure the sealing material. Therefore, there is a problem that it is not suitable for mass continuous production and a lateral shift occurs between two substrates aligned in advance. In addition, when the materials of the pair of substrates are different from each other, there is a problem that the alignment is likely to be inaccurate due to the difference in thermal expansion coefficient of each substrate in the heating process. Furthermore, there has been a problem that the thickness of the cell tends to be non-uniform. Due to these disadvantages, there is a drawback that the display quality of the obtained liquid crystal display panel is lowered.
On the other hand, a liquid crystal panel using an ultraviolet curable resin as a sealing material has been reported in Patent Document 1, Patent Document 2, and Patent Document 3. However, any of the sealing materials has insufficient adhesive strength at the interface with the glass surface or plastic surface serving as the substrate, and in particular, interface peeling may occur due to stress applied in a direction parallel to the substrate surface. there were.
In general, in the adhesive field, there are several methods for increasing the adhesive strength against interface peeling by examining the composition. However, when the LCD is manufactured by the liquid crystal dropping method (ODF method), the uncured sealing material and the liquid crystal are in direct contact with each other, so that the raw material for the sealing material is limited so as not to contaminate the liquid crystal.
Thus, the present condition has not yet obtained what satisfy | filled the said required characteristic only with a sealing material.

Japanese Patent Laid-Open No. 10-330717 JP 2004-004612 A JP 2005-171135 A

The problem to be solved by the present invention is that there is no peeling near the interface between the substrate and the sealing material, and in particular, there is no occurrence of interface peeling due to stress applied in the direction parallel to the substrate surface. Is to provide.

The present inventors solved the above problems by providing protrusions on the surface of the substrate in contact with the sealing material.

That is, the present invention includes two substrates facing each other, a sealing material provided between the substrates, and a liquid crystal sealed in a sealing region surrounded by the sealing material, and the substrate in contact with the sealing material Provided is a liquid crystal display element having projections on its surface.

The present invention also provides a method for producing the liquid crystal display element described above,
A step of simultaneously providing a spacer provided on a surface to be a sealing region on a front substrate provided with a color filter and a protrusion provided on a surface in contact with a sealing material by a photolithography method or a droplet discharge method;
A step of applying a sealing material to a surface provided with a protrusion on which the sealing material on the front substrate provided with the color filter comes into contact;
Dropping a liquid crystal on a sealing region of a front substrate provided with the color filter;
There is provided a method for producing a liquid crystal display element, comprising a step of bonding a front substrate provided with the color filter and a rear substrate provided with a TFT through a sealing material.
In other words, the method for manufacturing the liquid crystal display element described above,
On the surface provided with the color filter of the front substrate, which has a portion to be a sealing region and a portion on which a sealing material that forms the sealing region is provided.
A step of simultaneously providing a spacer in a portion to be the sealing region and a protrusion in a portion to be in contact with the sealing material by a photolithography method or a droplet discharge method;
A step of applying a sealing material to a portion where the protrusion is provided and the sealing material is provided;
Dropping liquid crystal on the sealing region of the front substrate;
Bonding the front substrate and the rear substrate provided with TFTs through a sealing material;
A method for manufacturing a liquid crystal display element, comprising:

According to the present invention, it is possible to provide a liquid crystal display element that does not peel near the interface between the substrate and the sealing material, and that does not cause interface peeling due to stress applied in a direction parallel to the substrate surface.
The protrusions are formed on the front substrate provided with the color filter by a photolithography method or a droplet discharge method, with a spacer on the surface to be a sealing region, and a protrusion on the surface to be in contact with the sealing material. By providing, it can be easily attached.
In addition, since the liquid crystal display element of the present invention can form a seal region with little variation in seal width, the area of the sealing region for sealing the liquid crystal can be formed stably, and liquid crystal injection by an ODF (one-drop-fill) method is possible. It also has features such as being suitable for the seal and excellent in narrowing the seal width.

It is sectional drawing which shows an example of the liquid crystal display element of this invention. It is a figure which shows an example of the protrusion pattern of this invention. It is a figure which shows the exposure process process using the pattern A which has both the spacer preparation pattern which forms a spacer on a black matrix as a photomask pattern, and the protrusion creation pattern which forms a protrusion in a sealing material application part. .

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which interface peeling or the like hardly occurs at a seal portion even when a thin film substrate or a flexible substrate is used.
Hereinafter, preferred embodiments of a liquid crystal display device according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these examples, and changes, additions, omissions, and the like may be made without departing from the present invention, such as the number, position, size, and type of material. In the drawings, the scale, number, and the like may be different from the actual structure in order to make each configuration easy to understand.
1 and 2 include two substrates facing each other, a sealing material provided between the substrates, and liquid crystal sealed in a sealing region surrounded by the sealing material, and the sealing material is in contact with each other. It is a fragmentary sectional view which shows the liquid crystal display element by which the processus | protrusion is provided in the one or both board | substrate surface.
Specifically, a specific mode of the liquid crystal display element is shown. In these drawings, a substrate having members with reference numerals 100 to 105 is referred to as a “back substrate”, and a substrate having members having reference numerals 200 to 205 is referred to as a “front substrate”. More specifically, the rear substrate is obtained by providing the TFT layer 102 and the pixel electrode 103 on the substrate a100 provided with the barrier film 101, and providing the passivation film 104 and the alignment film a105 thereon. The front substrate facing the rear substrate is obtained by providing a black matrix 202, a color filter 203, and a transparent electrode 204 on a substrate b200 provided with a barrier film 201, and an alignment film b205 thereon. Between the two substrates, a sealing material 301 and a liquid crystal layer 303 sealed in a sealing region surrounded by the sealing material are provided, and one of the substrate surfaces of the two substrates in contact with the sealing material 301 is provided. Or, both are provided with protrusions 304. 1 is a cross-sectional view in which the protrusions 304 are provided on the front substrate, and FIG. 2 is a cross-sectional view in which the protrusions 304 are provided on both the front substrate and the back substrate.

The material of the substrate a or the substrate b is not particularly limited as long as it is substantially transparent. For example, glass, ceramics, plastics, etc. can be used. Examples of plastic substrates include cellulose derivatives such as cellulose, triacetyl cellulose, diacetyl cellulose, polycycloolefin derivatives, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polypropylene, Polyolefins such as polyethylene, polycarbonate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyamide, polyimide, polyimide amide, polystyrene, polyacrylate, polymethyl methacrylate, polyether sulfone, polyarylate, and glass fiber -An inorganic-organic composite material such as epoxy resin, glass fiber-acrylic resin, or the like can be used.
When a plastic substrate is used, it is preferable to provide a barrier film (101 and 201 in FIG. 1). The function of the barrier film is to reduce the moisture permeability of the plastic substrate and to improve the reliability of the electrical characteristics of the liquid crystal display element. The

barrier films

101 and 201 are not particularly limited as long as they have high transparency and low water vapor permeability. In general, a thin film formed by vapor deposition, sputtering, or a chemical vapor deposition method (CVD method) using an inorganic material such as silicon oxide can be used.
In the present invention, the same material or different materials may be used as the substrate a and the substrate b, and there is no particular limitation. The plastic substrate is preferable because it is suitable for a production method by a roll-to-roll method and is suitable for weight reduction and flexibility. In the present invention, a plastic substrate and a glass substrate may be combined for the purpose of imparting flatness and heat resistance.
In the examples described later, a composite material of glass cloth and curable resin is used as the material of the substrate a100 or the substrate b200, and silicon oxide is used as the material of the

barrier films

101 and 201.

In the rear substrate, a TFT layer 102 and a pixel electrode 103 are provided on a substrate a100 provided with a barrier film 101. These layers are manufactured by a normal array process. A passivation film 104 and an alignment film a105 are provided thereon to obtain a back substrate.
A passivation film 104 (also referred to as an inorganic protective film) is a film for protecting the TFT layer. Usually, a nitride film (SiNx), an oxide film (SiOx), or the like is formed by a chemical vapor deposition (CVD) technique or the like.
The alignment film a105 is a film having a function of aligning liquid crystals, and a polymer material such as polyimide is usually used in many cases. As the coating liquid (alignment agent solution) for forming the alignment film, an alignment agent solution composed of a polymer material and a solvent is usually used. Since the alignment film may hinder the adhesive force with the sealing material, a pattern is applied in the sealing region. For the application, a printing method such as a flexographic printing method or a droplet discharge method such as an ink jet method can be used. The applied alignment agent solution is crosslinked and cured by baking after the solvent is evaporated by temporary drying to obtain a polymer film. Thereafter, an alignment process is performed to provide an alignment function.
A rubbing method is usually used for the alignment treatment. The polymer film formed as described above is rubbed in one direction using a rubbing cloth made of fibers such as rayon, thereby producing liquid crystal alignment ability.
Moreover, the photo-alignment method may be used. The photo-alignment method is a method of generating alignment ability by irradiating polarized light onto a film containing an organic material having photosensitivity, and does not cause damage to the substrate or dust due to the rubbing method. Examples of the organic material in the photo-alignment method include a material containing a dichroic dye. Dichroic dyes include molecular orientation induction or isomerization reaction (eg azobenzene group), dimerization reaction (eg cinnamoyl group), photocrosslinking reaction (eg benzophenone group) due to Weigert effect due to photodichroism. Alternatively, a dye having a group (hereinafter abbreviated as a photo-alignment group) that causes a photoreaction that causes liquid crystal alignment ability, such as a photodecomposition reaction (eg, polyimide group) can be used. When using the photo-alignment method, the applied alignment agent solution is irradiated with light (polarized light) having an arbitrary deflection after the solvent is evaporated by temporary drying, thereby obtaining an alignment film having an alignment ability in an arbitrary direction. be able to.

On the other hand, the front substrate is provided with a black matrix 202, a color filter 203, a transparent electrode 204, and an alignment film b205 on a substrate b200 provided with a barrier film 201.
The black matrix 202 is produced by, for example, a pigment dispersion method. Specifically, a color resin solution in which a black colorant is uniformly dispersed for forming a black matrix is applied on a substrate b200 provided with a barrier film 201, thereby forming a colored layer. Subsequently, the colored layer is baked and cured. A photoresist is applied on this and prebaked. The pre-baked photoresist is exposed through a mask pattern having holes having a desired shape and pattern, and then developed to remove unnecessary portions, thereby patterning the colored layer. Thereafter, the photoresist layer on the patterned colored layer is peeled off, and the colored layer is baked to complete the black matrix 202.
Alternatively, a photoresist type pigment dispersion may be used. In this case, a photoresist-type pigment dispersion is applied, pre-baked, exposed through a mask pattern, and then developed to pattern the colored layer. Thereafter, the colored layer is baked to complete the black matrix 202.

The color filter 203 is created by, for example, a pigment dispersion method, an electrodeposition method, a printing method, or a staining method. Taking the pigment dispersion method as an example, it can be obtained by the following steps. A color resin liquid in which a pigment (for example, red) is uniformly dispersed is applied onto a substrate b200 provided with a barrier film 201, and this is baked and cured. Thereafter, a photoresist is further applied on the obtained cured film and prebaked. The pre-baked photoresist is exposed through a mask pattern and then developed and patterned. Thereafter, the patterned photoresist layer on the cured film is peeled off and baked again to complete the (red) color filter 203. There is no particular limitation on the color order to be created. Similarly, the green color filter 203 and the blue color filter 203 can be formed.

The transparent electrode 204 is provided on the color filter 203 (if necessary, on an overcoat layer (not shown) provided on the color filter 203 for surface flattening). The transparent electrode 204 preferably has a high transmittance, and preferably has a low electrical resistance. As the transparent electrode 204, an oxide film such as ITO is formed by sputtering or the like.
In addition, a passivation film may be provided on the transparent electrode 204 for the purpose of protecting the transparent electrode 204.
The description of the alignment film b205 can be the same as that of the alignment film a105 described above.

Although specific embodiments of the back substrate and the front substrate used in the present invention have been described above, the present invention is not limited to the specific embodiments as described above, and the liquid crystal display element is desired. The change of the aspect which respond | corresponds is free. For example, when glass is used for the substrates a and b, the

barrier films

101 and 201 need not be used.

The liquid crystal element of the present invention includes the back substrate and the front substrate facing each other, a sealing material provided between the substrates, and a liquid crystal sealed in a sealing region surrounded by the sealing material, The material is in contact with the rear substrate and the front substrate, and a protrusion is provided at one or both of the inner surface of the rear substrate and the inner surface (substrate surface) of the front substrate where the sealing material contacts. .
The position where the sealing material contacts the substrate surface is usually located at the end of the substrate. The position is not particularly limited, but is usually provided with a width in the range of 0.5 mm to 5 mm from the edge of the substrate. For example, when the liquid crystal element to be formed has a square shape, sealing materials having a width of 0.5 mm to 5 mm are provided on the upper, lower, left and right ends of the shape, that is, on the four sides. The protrusion provided at this position is preferably provided such that the bottom area thereof is in a ratio of 0.1% to 16% with respect to the area of the substrate surface (one surface) where the sealing material is in contact with the substrate. . If it is less than 0.1%, the anti-peeling action may be weak, and if it exceeds 16%, the coating amount of the sealing material may be too small.
Specifically, with respect to an area 1 mm ² of the substrate surface on which the sealing member is in contact with one substrate, protrusions footprint per one projection is 100μm ^² ~ 1600μm ² is provided approximately 10-100 It is preferable that the strength is increased with respect to the stress applied in the direction parallel to the substrate surface. Here, the projection installation area is the area of the projection installation surface (projection bottom surface) on the substrate surface (sealing material region) on which the projection is installed.
The substrate surface of the substrate on which the protrusion is provided may be on either the back substrate or the front substrate. However, in the case of the back substrate, since the process of providing the protrusion in the manufacturing process of providing the TFT or the like causes the process to be complicated, the back substrate is often provided on the front substrate capable of relatively simplifying the manufacturing process. .
Further, the surface on which the protrusion is directly provided is on the transparent electrode 204 of the front substrate in the specific embodiment of FIG. Alternatively, when a passivation film is provided on the transparent electrode 204 (not shown), the surface directly touched by the bottom surface of the protrusion 304 is the surface of the passivation film 104.
The height of the protrusion is preferably a height that does not exceed the cell gap (interval between the substrates).

The shape of the protrusion is not particularly limited and can be arbitrarily selected. The horizontal cross section of the protrusion relative to the substrate can be various shapes such as a circle, a polygon such as a quadrangle. In consideration of a misalignment margin during the process, it is particularly preferable that the horizontal cross section is a circle or a regular polygon. The protrusion shape is preferably a truncated cone or a truncated pyramid. Arrangement positions of the protrusions can be arbitrarily selected.

The material of the protrusion is not particularly limited as long as it is a material that can be used for the sealing material, an organic solvent that can be used for forming the sealing material, or a material that does not dissolve in the liquid crystal. From the viewpoint of processing and weight reduction, a synthetic resin (curable resin) is preferable. Specific examples include (meth) acrylic polymers and urethane polymers.
The protrusions can be formed by any method. To give a preferable example, the protrusions can be provided on the portion where the sealing material on the first substrate (front substrate) should come into contact by a photolithography method or a droplet discharge method. is there. For this reason, it is preferable to use a photocurable resin suitable for the photolithography method or the droplet discharge method for forming the protrusions. If the specific example of a photocurable resin is given, the (meth) acrylic-type monomer which has an unsaturated group, a urethane-type monomer, a polyol monomer etc. will be mentioned.

As described above, the height of the protrusion is preferably a height that does not exceed the cell gap. The spacer has a function of keeping the distance between the substrates constant. For this reason, the height of the protrusion may be equal to or lower than that of the spacer. For these reasons and from the viewpoint of simplification of work, it is preferable that the protrusion is formed at a predetermined position on the substrate together with the spacer when the spacer is provided.

For example, when the spacer is obtained on the front substrate by photolithography, the protrusion can be provided on the surface of the front substrate that contacts the sealing material at the same time.
The following processes are mentioned as a specific example which produces a spacer and protrusion simultaneously. First, a resin solution for spacer formation (not containing a colorant) is applied on the transparent electrode 204 of the front substrate. Subsequently, the resin layer is baked and cured. A photoresist is applied on this and prebaked. After the prebaked photoresist layer is exposed through a predetermined mask pattern, development is performed to remove unnecessary portions of the resin layer and the photoresist layer, and the resin layer is patterned. Thereafter, the photoresist layer left on the patterned resin layer is peeled off, and the resin layer is baked to complete the spacer.
The formation position of the spacer can be determined at a desired position by selecting a mask pattern. Therefore, if necessary, spacers can be simultaneously formed in both the sealing region and the outside of the sealing region (sealing material application portion) of the liquid crystal display element. In the present invention, a spacer formed outside the sealing region can be used as the protrusion. The spacer formed in the sealing region is preferably formed so as to be positioned on the black matrix so that the quality of the sealing region does not deteriorate. In the present invention, a spacer manufactured by a photolithography method in this way may be referred to as a column spacer or a photo spacer. Note that the droplet discharge method is a method in which spherical spacers are dispersed in a solvent in which an adhesive is dissolved, and are arranged at predetermined positions by inkjet, and the same spherical spacers as the scattering spacers are formed.

Further, for example, even when a spacer is obtained on the front substrate by a droplet discharge method, the protrusion can be provided at a predetermined position on the surface of the front substrate that contacts the sealing material.
Specifically, in the specific mode of FIG. 1, a droplet dispersion spacer liquid dispersion composed of a gap material, a binder resin, and a solvent having a desired size is discharged onto the transparent electrode 204 of the front substrate, Place the gap material at a fixed point. When the solvent is dried and then heated to a temperature equal to or higher than the curing temperature of the binder resin to cure the resin, a spacer including the binder resin and a gap material having a desired shape such as a sphere or fiber is completed.
The formation position of the spacer can be determined as desired according to the droplet discharge position. Therefore, spacers can be simultaneously formed both in the sealing region of the liquid crystal display element and outside the sealing region (sealing material application portion). As described above, the spacer formed outside the sealing region can be used as a protrusion. The spacer in the sealing region is preferably formed so as to be positioned on the black matrix so that the quality of the sealing region does not deteriorate.

The material of the spacer can be arbitrarily selected. For example, a negative water-soluble resin such as a PVA-stilbazo photosensitive resin, a mixture containing a polyfunctional acrylic monomer, an acrylic acid copolymer, a triazole-based initiator, or the like is used for spacer formation. Alternatively, there is a method using a color resin in which a colorant is dispersed in a polyimide resin.
In the present invention, there is no particular limitation, and the spacer can be obtained from a known material according to the compatibility with the liquid crystal or the sealing material to be used.
Therefore, when the protrusion is provided on the substrate together with the spacer, the protrusion is also formed of the same material as the spacer.

When the protrusions are provided on the substrate simultaneously with the spacers in this way, after providing the protrusions (spacers) in the portions that become the sealing regions on the front substrate surface and the protrusions in the portions that are outside the sealing regions, A sealing material (301 in FIG. 1) is applied to the portion of the front substrate surface that is in contact with the sealing material and has a projection (outside the sealing region).
The material for the sealing material is not particularly limited. For example, a curable resin composition in which a polymerization initiator is added to a photocurable, thermosetting, or photothermal combination curable resin such as an epoxy resin or an acrylic resin is used. In order to control moisture permeability, elastic modulus, viscosity, and the like, fillers made of inorganic or organic substances may be added. The shape of these fillers is not particularly limited, and includes a spherical shape, a fiber shape, and an amorphous shape. Furthermore, in order to control the cell gap satisfactorily, a spherical or fibrous gap material having a monodisperse diameter is mixed, or a fibrous material that tends to get entangled with the protrusions on the substrate in order to further strengthen the adhesion to the substrate. May be mixed. The diameter of the fibrous material used at this time is desirably about 1/5 to 1/10 or less of the cell gap, and the length of the fibrous material is desirably shorter than the seal coating width.
The material of the fibrous substance is not particularly limited as long as a predetermined shape can be obtained, and synthetic fibers such as cellulose, polyamide, or polyester, and inorganic materials such as glass or carbon can be appropriately selected. is there.
The method for applying the sealing material can be arbitrarily selected. For example, there are a printing method and a dispensing method, but a dispensing method with a small amount of sealant used is desirable. The application position of the sealing material is usually on the black matrix outside the sealing area so as not to adversely affect the sealing area. In order to form a liquid crystal dropping region used in the next step (so that the liquid crystal does not leak), the sealing material application shape is a closed loop shape. The specific shape of the closed loop shape, the arrangement of the closed loop, and the like can be arbitrarily set.

The liquid crystal is dropped on the inside (sealing region) of the closed loop shape of the front substrate formed by applying the sealing material. Although dripping is performed by arbitrary methods, a dispenser is usually used. The amount of liquid crystal to be dropped is basically the same as the volume obtained by multiplying the height of the spacer (column spacer) and the area of the closed loop shape (sealing region) coated with the seal in order to match the liquid crystal cell volume. . However, in order to optimize liquid crystal leakage and display characteristics in the cell bonding step, the amount of liquid crystal to be dropped may be appropriately adjusted or the liquid crystal dropping position may be dispersed.

Next, the back substrate is bonded to the front substrate on which the sealing material is applied and the liquid crystal is dropped. Specifically, the front substrate and the back substrate are adsorbed on a stage having a mechanism for adsorbing a substrate such as an electrostatic chuck, and the alignment film b on the front substrate and the alignment film a on the back substrate face each other. And it arrange | positions so that the position (distance) which a sealing material and another board | substrate (back substrate) may not contact may be maintained. In this state, the system is depressurized. After completion of the decompression, the positions of both substrates are adjusted while confirming the bonding position of the front substrate and the rear substrate (alignment operation). When the adjustment of the bonding position is completed, the two substrates are brought close to a position where the sealing material on the front substrate and the rear substrate are in contact with each other so that the bonding is correctly performed. In this state, the system is filled with an inert gas, and the pressure is gradually returned to normal pressure while releasing the reduced pressure. At this time, the front substrate and the rear substrate are bonded together by atmospheric pressure, and a cell gap is formed at the height position of the spacer (column spacer). In this state, a liquid crystal cell can be formed by irradiating the sealing material with ultraviolet rays and curing the sealing material. After this, a heating step is added depending on the case to accelerate the sealing material curing. A heating process is often added to enhance the adhesive strength of the sealing material and improve the reliability of electrical characteristics.

Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

(Formation of substrate (1))
After impregnating the glass fiber with the polyfunctional acrylate resin, it is continuously cured by an ultraviolet curing device to obtain a resin base material having a resin weight of 60%, glass fiber of 40%, width of 30 cm, length of 100 m, and thickness of 100 μm. It was. The linear expansion coefficient of this resin base material from 30 ° C. to 150 ° C. was 14 ppm. When the glass transition temperature of this resin substrate was evaluated by tan δmax, it was 300 ° C. or higher. The total light transmittance of this resinous substrate was 90%. The linear expansion coefficient is a value obtained by measuring a range of 30 to 150 ° C. using TMA (Thermal Mechanical Analyzer). The glass transition temperature was measured using DMA (Dynamic Mechanical Analyzer).
The total light transmittance was measured according to JIS K7361-1 (Plastic—Testing method for the total light transmittance of transparent materials).

This resin base material is loaded into a sputter roll coater, and by using DC magnetron sputtering, reactive sputtering using oxygen as a reactive gas and Si as a target, SiOx having a film thickness of 60 nm is formed on the resin base material. A barrier layer was formed by forming a film (x = 1.8, based on XPS) to obtain a substrate (1).

(Preparation of front substrates A and B)
(Formation of black matrix)
On the barrier layer of the substrate (1), a black matrix forming composition having the following composition was applied in a wet state using a die coater so as to have a thickness of 10 μm, dried, and then at a temperature of 90 ° C. For 2 minutes to form a black matrix layer having a thickness of 2 μm.

(Black matrix forming coating composition)
Benzyl methacrylate / methacrylic acid copolymer (molar ratio = 73/27) 300 parts Dipentaerythritol hexaacrylate 160 parts Carbon black dispersion 300 parts Photopolymerization initiator (2-benzyl-2-dimethylamino-1 -(4-morpholinophenyl) butanone-1) 5 parts, propylene glycol monomethyl ether acetate 1200 parts * All parts are based on mass

Thereafter, for exposure, the substrate (1) with the black matrix layer obtained above was passed through an exposure apparatus provided with an unwinding device on the upstream side and a winding device on the downstream side. At this time, a pair of nip rollers installed on the entrance side and the exit side of the exposure apparatus were driven to transport the continuous substrate (1) with the black matrix layer. In this transport state, the tension applied to the substrate (1) with the black matrix layer was 2 kg / 300 mm width.
The temperature of the main body of the exposure apparatus was adjusted to 23 ° C. ± 0.1 ° C., and the relative humidity was adjusted to 60% ± 1%.

In the exposure, after a part of the substrate (1) with the black matrix layer is adsorbed and fixed on the exposure table, the gap (gap) between the coating surface of the substrate (1) and the prepared pattern (photomask). Was automatically adjusted to 100 μm. The exposure position of the substrate (1) is automatically detected by automatically detecting the distance from the surface of the substrate (1) and automatically adjusting the distance from the substrate (1) to the photomask pattern position, and then intermittently exposing. Went. As a light source, a high-pressure mercury lamp was used, the exposure area was 200 mm × 200 mm, I-line (wavelength: 365 nm) was used, and exposure was performed at an illuminance of 15 mW / cm ² for 20 seconds to obtain an exposure amount of 300 mJ / cm ² . .

The developing process was performed by installing a developing device downstream of the exposure machine. The resin base material after the exposure treatment was conveyed at a constant speed of 400 mm / min to obtain a substrate (1) with a black matrix layer on which a black matrix having a predetermined pattern was laminated.

The alignment mark formed of the black matrix is measured with a dimension measuring machine (NEXIV VMR-6555 manufactured by Nikon) at a temperature of 23 ° C. ± 0.1 ° C., a relative humidity of 60% ± 1%, and in the conveying direction (MD). The dimensional change in the direction (TD) perpendicular to the transport direction was measured. As a result, the size of the pattern of the black matrix (alignment mark) actually formed on the resin base material is MD: 99.000 mm with respect to the photomask dimension values MD: 100.000 mm and TD: 100.000 mm. It was 998 mm and TD: 100.001 mm.
Then, the black matrix was thermally cured by post-baking at 200 ° C. for 30 minutes in a baking furnace. When the obtained black matrix was measured under the same conditions (temperature; 23 ° C. ± 0.1 ° C., relative humidity; 60% ± 1%), the pattern of the black matrix formed on the substrate (1) was measured. The dimensions after baking were MD: 99.998 mm and TD: 100.001 mm.

[Formation of RGB colored layer]
On the substrate (1) with the black matrix layer, a colored pattern forming composition having the following composition was applied in a wet state using a die coater so that the distance from the barrier layer was 10 μm. . This was dried and then pre-baked at a temperature of 90 ° C. for 2 minutes to obtain a black matrix layer and a substrate (1) with a colored pattern forming composition each having a thickness of 2 μm.

The composition of the red colored pattern forming composition is shown below. When the red pigment is an arbitrary green pigment, a GREEN colored pattern forming composition is obtained, and when a blue pigment is used, a BLUE colored pattern forming composition is obtained.

(Coloring pattern forming composition)
Benzyl methacrylate / methacrylic acid copolymer (molar ratio = 73/27) 50 parts Trimethylolpropane triacrylate 40 parts Red pigment (CI Pigment Red 177) 90 parts Photopolymerization initiator (2-methyl -1- [4- (Methylthio) phenyl] -2-morpholinopropanone-1) 1.5 parts ・ Propylene glycol monomethyl ether acetate 600 parts * All parts are based on mass

For exposure, the substrate (1) with the black matrix layer and the composition for forming a colored pattern obtained above was passed through an exposure apparatus provided with an unwinding apparatus on the upstream side and a winding apparatus on the downstream side. At this time, a pair of nip rollers installed on the entrance side and the exit side of the exposure apparatus were driven to transport the substrate (1) with a continuous black matrix layer and a composition for forming a colored pattern. In this transport state, the tension applied to the substrate (1) with the black matrix layer and the colored pattern forming composition was 2 kg / 300 mm width.
The temperature of the main body of the exposure apparatus was adjusted to 23 ° C. ± 0.1 ° C., and the relative humidity was adjusted to 60% ± 1%.
In the exposure, a part of the substrate (1) with the black matrix layer and the composition for forming a colored pattern is adsorbed and fixed on the exposure table, and then the substrate (1) with the black matrix layer and the composition for forming a colored pattern (1). Automatic adjustment was performed so that the gap (gap) between the coating surface and the prepared pattern (photomask) was 100 μm. Moreover, the exposure position of the board | substrate (1) with a black matrix layer and the composition for coloring pattern formation was determined as follows. That is, the distance from the surface of the substrate (1) with the black matrix layer and the colored pattern forming composition is automatically detected, and the photomask pattern position is detected from the substrate (1) with the black matrix layer and the colored pattern forming composition. Was automatically adjusted so as to be a constant distance, and then alignment with a RED photomask was performed using an alignment mark formed with a black matrix formed simultaneously with the formation of the black matrix layer, and then exposure was performed. As a light source, a high-pressure mercury lamp was used, the exposure area was 200 mm × 200 mm, I-line (wavelength: 365 nm) was used, and exposure was performed at an illuminance of 15 mW / cm ² for 20 seconds to obtain an exposure amount of 100 mJ / cm ² . .

Development was performed by installing a developing device downstream of the exposure machine. The substrate (1) with the black matrix layer and the composition for forming a colored pattern after the exposure process is conveyed at a constant speed of 400 mm / min, and as a result, at a predetermined position of the opening of the black matrix on the resin substrate, That is, a substrate (1) was obtained in which a RED colored layer having a predetermined pattern was laminated at a location where no black matrix was formed. Thereafter, post baking was performed at 200 ° C. for 30 minutes in a baking furnace, and the RED colored layer was cured.

The same method as RED is repeated to form a colored layer of GREEN and BLUE, and a color filter having a black matrix and a desired colored layer of RGB (RED, GREEN, and BLUE) formed on the substrate (1) Obtained.

In addition, when the alignment mark formed with the black matrix after the post-baking treatment of the BLUE colored layer was measured under the same conditions (temperature; 23 ° C. ± 0.1 ° C., relative humidity; 60% ± 1%), The dimensions of the pattern formed on the plastic film were MD: 99.999 mm and TD: 100.002 mm.

The dimensional change of the black matrix was 10 ppm in the production process from the development of the first layer (black matrix layer) to the post-baking of the fourth layer (BLUE layer). In this way, by arranging the RED layer, BLUE layer, and GREEN layer in a rectangular shape and in a predetermined position, the resolution is 200 ppi (BM (black matrix) line width) on a resin substrate with a 4-inch size. A color filter having a stripe structure of 7 μm and a pitch of 42 μm was able to be formed without causing a pixel shift.

(Formation of ITO electrode layer)
Subsequently, this color filter is loaded into a sputter roll coater, and a film is formed on the black matrix and RGB colored layers by using ITO (indium tin oxide) as a target by reactive sputtering using oxygen as a reactive gas by DC sputtering. An ITO film having a thickness of 150 nm was formed and used as an ITO electrode layer.

(Formation of spacers and protrusions)
(Preparation of dry film for forming pattern spacer)
A pattern spacer forming composition made of a negative photosensitive resin was applied on a PET base film (long roll) having a width of 300 mm and a thickness of 25 μm using a die coater so as to have a thickness of 20 μm in a wet state. . After the coating film was dried, it was prebaked for 2 minutes at a temperature of 90 ° C. to obtain a coating film having a thickness of 5 μm. Thereafter, a PET cover film having a thickness of 25 μm was laminated thereon to obtain a dry film for forming a pattern spacer.

(Creation of laminated raw material)
On the substrate (1) on which the black matrix, the RGB colored layer, and the ITO electrode layer obtained above were formed, the pattern spacer forming composition was prepared by removing the dry film for forming the pattern spacer from which the PET cover film was previously peeled off. Lamination was performed so as to face the ITO electrode layer. Thereafter, the composition layer for pattern spacer formation was continuously transferred under the conditions of roller pressure: 5 kg / cm ² , roller surface temperature: 120 ° C., and speed: 800 mm / min. At this time, the base film was not peeled off, and proceeded to the next exposure step in a state of being attached on the pattern spacer forming composition.

(Exposure process)
For exposure, the laminated raw material obtained above was passed through an exposure apparatus provided with an unwinding device on the upstream side and a winding device on the downstream side. At this time, a pair of nip rollers installed on the entrance side and the exit side of the exposure apparatus were driven to transport the laminated raw material having a continuous shape. In this conveying state, the tension applied to the laminated original fabric was 2 kg / 300 mm width.
The temperature of the main body of the exposure apparatus was adjusted to 23 ° C. ± 0.1 ° C., and the relative humidity was adjusted to 60% ± 1%.
In exposure, after a portion of the stack is sucked and fixed on the exposure table, the gap (gap) between the base film of the stack and the prepared photomask pattern (photomask) is automatically adjusted to 30 μm. did. As a photomask pattern used at this time, a pattern A (see FIG. 3) having both a spacer creation pattern for forming a spacer on a black matrix and a projection creation pattern for forming a projection on a sealing material application portion, and comparison For this purpose, a pattern B having only a spacer forming pattern for forming a spacer on a black matrix was prepared.
Moreover, the exposure position of the pattern of the laminated original fabric was determined as follows. In other words, after automatically detecting the distance from the surface of the laminated original fabric and automatically adjusting the photomask pattern position from the laminated original fabric to a certain distance according to this detection result, it was simultaneously formed when forming the black matrix After alignment with a photomask for spacers using a black matrix alignment mark, exposure was performed. As a light source, a high-pressure mercury lamp was used, the exposure area was 200 mm × 200 mm, I-line (wavelength: 365 nm) was used, and exposure was performed at an illuminance of 15 mW / cm ² for 20 seconds to obtain an exposure amount of 300 mJ / cm ² . . Exposure was performed using each pattern.

(Development and post-baking process)
The development process was performed while a developing device was installed on the downstream side of the exposure machine and the film was transported at a constant speed of 400 mm / min while peeling the base film of the laminated original film after exposure in this developing device. As a result, on the substrate (1) on which the black matrix, the RGB colored layer, and the ITO electrode layer are formed, and in a predetermined position on the lattice pattern portion of the black matrix, A color filter having protrusions was obtained. Thereafter, post-baking treatment was performed at 200 ° C. for 30 minutes in a baking furnace, and the spacers or spacers and protrusions having a predetermined pattern were thermally cured.

Thus, using the pattern A, the front substrate A on which the black matrix, the RGB colored layer, the ITO electrode layer, the pattern spacer, and the protrusions were formed on the substrate (1), and the pattern B were used. A front substrate B having a black matrix, an RGB colored layer, an ITO electrode layer, and a pattern spacer formed on the substrate (1) was obtained.

(Create back substrate)
(Formation of TFT electrode layer)
A quartz glass substrate was used as the transparent substrate, and a TFT electrode layer was formed on the transparent substrate according to the method described in JP-A-2004-140381.
That is, after forming an amorphous Si layer with a thickness of 100 nm on a quartz glass substrate, an oxide Si layer (SiOx) was formed thereon by a vacuum film forming method. Thereafter, a TFT layer and a pixel electrode were formed on the oxidized Si layer by using a photolithography method and an etching method, respectively.
Next, a water-soluble adhesive was applied on the TFT layer and the pixel electrode, and a separately prepared glass substrate was attached. After that, XeCl excimer laser was irradiated from the first quartz glass substrate side to peel off at the interface between the amorphous Si layer and the oxidized Si layer.
By such a method, a TFT array layer in which a TFT layer and a pixel electrode were formed on an SiOx layer having a thickness of 0.1 μm was formed. A TFT layer and a pixel electrode exist between the SiOx layer and the glass substrate.

(Preparation of resin substrate with TFT)
The TFT array layer is sandwiched between two substrates on the glass substrate on which the TFT array layer is formed, that is, another substrate is disposed on the surface of the SiOx layer that is in contact with the amorphous Si layer. A substrate (1) similar to that used for the front substrates A and B was bonded.
Here, a low curing shrinkage type curable adhesive (Luxtrac LCR0629B manufactured by Toagosei Co., Ltd.) was used. The adhesive is applied to the SiOx side on which the substrate (1) is bonded, and then the TFT array layer and the substrate (1) are bonded on the bonding apparatus using alignment marks previously formed on the respective substrates. After the alignment was performed in a state where the distance from the substrate was separated by 100 μm, bonding was performed. Thereafter, the glass substrate and the water-soluble adhesive formed on the TFT array layer were peeled off to obtain a resin substrate with a TFT array as a back substrate.

(Creation of liquid crystal cell A for Example)
(Alignment film formation)
A liquid crystal alignment film was formed as follows in a portion corresponding to the sealing region of the front substrate A and the back substrate manufactured as described above.
After washing both substrates with pure water, a liquid crystal aligning agent was applied to a portion corresponding to the sealing region using a printer for applying a liquid crystal alignment film and dried in an oven at 180 ° C. for 20 minutes. In this way, a thin coating film having a dry average film thickness of 600 mm was formed on the surface of the front substrate A on which the ITO was formed and on the surface of the rear substrate on which the TFT electrode layer was formed. A rubbing machine having a roll in which a rayon cloth is wound around this coating film is rubbed at a roll rotation speed of 400 rpm, a stage moving speed of 30 mm / second, and a hair foot indentation length of 0.4 mm, and then washed with water. It was. Then, it dried for 10 minutes on 120 degreeC oven.

The sealant was applied to the portion of the front substrate A where the sealant was to be applied using a dispenser so as to draw a closed loop.
As the sealing material, a photo-curing type sealing material was used, and 1% by weight of spherical spacers having the same size as the spacer (column spacer) were mixed in the sealing material. In order to evaluate the difference due to the difference in seal width, three types of sample cells A1 to A3 were prepared. That is, the application width of the sealing material was set to three types of seal widths suitable for an evaluation test described later (1.2 mm, 2 mm, and 3 mm).

Subsequently, an appropriate amount of liquid crystal was dropped using a dispenser at a predetermined position in the closed loop formed by the sealing material.
Subsequently, the front substrate A and the rear substrate after dropping the liquid crystal were adsorbed to the electrostatic chuck. The front substrate A and the rear substrate were disposed so as to face each other, and the rear substrate was slowly lowered to stand still at a distance of 300 μm from the front substrate A. In this state, the pressure in the vacuum chamber was reduced to 100 Pa. The alignment position of the front substrate A and the rear substrate was adjusted using an alignment mark formed in advance. After the alignment was completed, the front substrate A and the rear substrate were brought closer to each other, and both base materials were held at a height where the sealing material and the TFT electrode layer were in contact with each other. In this state, an inert gas was introduced into the vacuum chamber, and the system was returned to atmospheric pressure. The front substrate A and the back substrate were pressed by atmospheric pressure, and a cell gap was formed at the height of the spacer (column spacer) including the liquid crystal alignment film. Subsequently, the sealing material application portion was irradiated with ultraviolet rays (365 nm, 30 kJ / m ² ) to cure the sealing material, and liquid crystal cells A (A1 to A3) were obtained.

(Creation of liquid crystal cell C for Example)
In the liquid crystal cell A, liquid crystal cells C (C2 to C3) were obtained in the same manner as in the above method except that a sealing material to which a fibrous substance was added was used. The amount of the fibrous substance added was 1 part by weight with respect to 100 parts by weight of the sealing material. As the fibrous material, cellulose ultrafine fibers were used, and the fibers themselves were produced according to the method described in Japanese Patent Application Laid-Open No. 2008-266828. The obtained ultrafine cellulose fibers had an average fiber diameter of about 1 μm and an average fiber length of about 0.2 mm.

(Comparative liquid crystal cell B)
Liquid crystal cells B (B1 to B3) were obtained in the same manner as the liquid crystal cell A except that the front substrate B was used instead of the front substrate A. Considering that no column spacers (protrusions) are formed in the seal formation region in the liquid crystal cell B, the sealing material has approximately the same size as the column spacer so that a cell gap equivalent to that in the liquid crystal filling region can be maintained. 1% by weight of a spherical spacer was mixed.

<Seal width evaluation>
(Measurement method of seal width)
The seal width of the liquid crystal cell was measured using a digital microscope (KH-7700, manufactured by Hilox). The measurement interval of the seal width was set to 2 mm, 64 points were measured, and the average value and the standard deviation were obtained. The variation in the seal width was evaluated by 3σ / average value × 100 (%) (σ = standard deviation).

(Seal width variation and controllability evaluation)
In the liquid crystal cell preparation method, the liquid crystal cell A1 and the liquid crystal cell A2, and the liquid crystal cell B1 and the liquid crystal cell B2 for comparison, which were set to have a seal width of 1.2 mm or 2 mm, were used.
Table 4 shows the measurement results of the seal widths of the liquid crystal cell A and the liquid crystal cell B.

When the seal width was 1.2 mm, the variation in the seal width of the liquid crystal cell A (A1) was as small as about one third compared with the variation of the liquid crystal cell B (B1). Even when the seal width was 2 mm, the liquid crystal cell A (A2) had small seal width variations, and was able to achieve almost the target seal width. In contrast, in the liquid crystal cell B (B2), when the seal width was 2 mm, the target seal width was greatly exceeded.
From this result, it can be seen that by providing a protrusion on the seal application part, it is possible to suppress the variation in the seal width and to improve the controllability of the seal width.

In addition, as a result of observing the seal portion of both types of liquid crystal cells by magnifying them about 100 to 200 times using a transmission type optical microscope, the spherical spacers dispersed in the seal material are narrower than the seal width. It was confirmed that they were unevenly distributed. In particular, in the liquid crystal cell B having no protrusion, the sealing material tends to extend in the seal width direction, which is considered to be because the sealing material easily flows on the side where the spherical spacers are not dispersed. As a result, the seal width was wide and the variation was large. In the liquid crystal cell A provided with the protrusions, the provided protrusions or spacers suppress excessive flow of the sealing material, and thus it is considered that the variation in the seal width is suppressed to a small value. From this, it was shown that by forming a spacer (column spacer) in the sealant application portion, the seal width controllability is improved and effective for narrowing the frame of the liquid crystal panel.

(Adhesion evaluation 1)
According to the method according to JIS-K-6854, a 90 ° peel test of the liquid crystal cell was performed using a tensile tester (Tensilon, manufactured by A & D), and the stress when the substrate peeled was measured.
Specifically, the end (mimi) of the substrate of the produced liquid crystal cell A, B or C was fixed to a tensilon air chuck, and the other substrate was fixed to a 90 ° peel test dedicated jig.
The air chuck side was pulled upward at a pulling speed of 100 mm / min. At this time, the other substrate moved horizontally on the dedicated jig.
The apparatus was stopped when the air chuck was lifted by about 50 mm while peeling the cell substrate.
From the stress when the cell substrate started to peel to the stress when the apparatus was stopped, the average value was obtained.
The stress was normalized by the seal width, and the stress per 1 m of the seal width was defined as the peel strength.

(Peel strength 1)
The peel strength of the liquid crystal cells A (A1 to A3) was about 5 × 10 ² N / m on average. At the time of peeling, the seal was not peeled off at the cell substrate interface, and was destroyed from the inside of the substrate. In contrast, the peel strength of the liquid crystal cells B (B1 to B3) was about 1 × 10 ² N / m on average, and the seal peeled off at the cell substrate interface at the time of peeling.
From this result, it was proved that it is possible to greatly increase the breaking strength of the cell by providing the protrusion on the sealing material application portion.

(Peel strength 2)
The peel strength in the liquid crystal cells C (C1 to C3) is about 7 × 10 ² N / m on average, and by mixing a fibrous substance in the sealing material, the breaking strength of the cells can be increased. I knew it would be possible.

Provided is a liquid crystal display element that is free from peeling near the interface between a substrate and a sealing material, and that does not cause peeling especially due to stress applied in a direction parallel to the substrate surface.

100: Substrate a
101: barrier film 102: TFT layer 103: pixel electrode 104: passivation film 105: alignment film a
200: Substrate b
201: Barrier film 202: Black matrix 203: Color filter 204: Transparent electrode 205: Alignment film b
301: Sealing material 302: Column spacer 303: Liquid crystal layer 304: Protrusion 401: Pattern A
402: Composition for forming pattern spacer 403: Base film

Claims

Two substrates facing each other, a sealing material provided between the substrates, and a liquid crystal sealed in a sealing region surrounded by the sealing material, and a protrusion is provided on a substrate surface in contact with the sealing material A liquid crystal display element characterized by comprising:
Two substrates facing each other, a sealing material provided between the substrates, and a spacer disposed in a sealing region surrounded by the sealing material,
The liquid crystal display element according to claim 1, wherein a protrusion is provided on at least one substrate surface of the two substrates in contact with the sealing material, and the protrusion is obtained from the same material as the spacer.
The liquid crystal display device according to claim 1 or 2 footprint per the projections is in the range of 100 [mu] m 2 ~ 1600 .mu.m 2.
4. The liquid crystal display element according to claim 1, wherein the protrusions are provided at a rate of 0.1% to 16% per unit area of the substrate surface in contact with the sealing material.
5. The liquid crystal display element according to claim 1, wherein the shape of the protrusion is a truncated cone or a truncated pyramid.
6. The liquid crystal display element according to claim 1, wherein the sealing material contains a fibrous substance.
The liquid crystal display element according to any one of claims 1 to 6, wherein the sealing material is photocurable.
The liquid crystal display element according to claim 1, wherein the spacer is a column spacer.
A method for producing a liquid crystal display element according to any one of claims 1 to 7,
On the surface provided with the color filter of the front substrate, which has a portion to be a sealing region and a portion on which a sealing material that forms the sealing region is provided.
A step of simultaneously providing a column spacer in the portion to be the sealing region and a protrusion in a portion to be in contact with the sealing material by a photolithography method or a droplet discharge method;
A step of applying a sealing material to a portion where the protrusion is provided and the sealing material is provided;
Dropping liquid crystal on the sealing region of the front substrate;
Bonding the front substrate and the rear substrate provided with TFTs through a sealing material;
A method for producing a liquid crystal display element, comprising:
The liquid crystal display element according to claim 9, wherein the sealing material is a photocurable type, and includes a step of performing light irradiation after the front substrate and a rear substrate provided with TFTs are bonded together via the sealing material. Production method.
The method for manufacturing a liquid crystal display element according to claim 9, wherein the spacer is a column spacer.