JP6181396B2 - Liquid crystal composition - Google Patents

Description

The present invention relates to a liquid crystal composition, a polymer / liquid crystal composite, a liquid crystal element, and a liquid crystal display device.

In recent years, flat panel displays have been put into practical use, and are replacing conventional displays using cathode ray tubes. Flat panel displays include a liquid crystal display device having a liquid crystal display element, an EL display device having an electroluminescence element (EL element), a plasma display, and the like, and these are competing in the market. At present, liquid crystal display devices are in a dominant position in the market by overcoming the drawbacks of various technologies and controlling production costs.

One of the points that the above-mentioned liquid crystal display device is inferior to other flat panel displays is the response speed of the element (display switching speed). Various techniques have been proposed so far in order to overcome the drawback of response speed. In a conventional liquid crystal element adopting a so-called TN (twisted nematic) mode liquid crystal driving method, the response speed is about 10 ms. The response speed is improved up to about 1 ms by using.

As a technique that attracts attention along with such a liquid crystal driving method, there is a technique that uses a state called a blue phase for a liquid crystal display element. The blue phase is, for example, a liquid crystal phase that appears between a cholesteric phase and an isotropic phase, and has a feature that the response speed is extremely high. By using this blue phase, the response time of the liquid crystal display device can be set to 1 ms or less.

In the blue phase, the narrow temperature range is a major problem, but by forming a three-dimensional network structure of the polymer in the liquid crystal composition in which the blue phase is expressed, the temperature at which the blue phase appears Has been reported (for example, Patent Document 1).

In Patent Document 1, in order to form a three-dimensional network structure of a polymer in a liquid crystal composition, a polymerizable monomer is added to the liquid crystal composition, and this is polymerized by irradiation with ultraviolet rays.

JP 2003-327966 A

However, in order to polymerize the monomer by irradiating with ultraviolet rays, in addition to the monomer, a polymerization initiator that absorbs ultraviolet rays and initiates polymerization of the monomer needs to be added to the liquid crystal composition. Therefore, the manufacturing process of the liquid crystal element has increased.

In order to achieve the above object, an object of one embodiment of the present invention is to provide a liquid crystal composition using a monomer that also functions as a polymerization initiator.

One embodiment of the present invention is a liquid crystal composition including a liquid crystal material exhibiting a blue phase and a liquid crystal monomer represented by General Formula (G1) below.

However, in General Formula (G1), R ¹ and R ² each independently represent either hydrogen or a methyl group. In the general formula (G1), X ¹ and X ² each independently represent either hydrogen or a methyl group. In general formula (G1), n and m are each independently an integer of 2 to 20.

Another embodiment of the present invention is a liquid crystal composition including a liquid crystal material exhibiting a blue phase and a liquid crystal monomer represented by General Formula (G2) below.

However, in the general formula ^{(G2), R 1, R} 2 represents any one of the independently hydrogen or a methyl group. In general formula (G2), n and m are each independently an integer of 2 to 20.

Another embodiment of the present invention is a liquid crystal composition including a liquid crystal material exhibiting a blue phase and a liquid crystal monomer represented by General Formula (G3) below.

However, in general formula (G3), R < ¹ >, R < ² > represents either hydrogen or a methyl group each independently.

The liquid crystalline monomer represented by the general formula (G1), the general formula (G2), or the general formula (G3) is a liquid crystal composition including a liquid crystalline monomer represented by the following structural formula (100).

In the liquid crystalline monomer represented by the general formula (G1), general formula (G2), or general formula (G3), the wavelength of the light absorption edge is preferably larger than 320 nm, and more preferably larger than 365 nm.

In addition, the liquid crystalline monomer represented by the structural formula (100) can have a wavelength of light absorption edge larger than 365 nm.

Another embodiment of the present invention may include a non-liquid crystalline monomer in the above. Moreover, the chiral agent may be included.

Another embodiment of the present invention may be a liquid crystal composition including a mixture of the above liquid crystal monomer, a non-liquid crystal monomer, a liquid crystal material exhibiting a blue phase, and a chiral agent.

Another embodiment of the present invention is a polymer / liquid crystal composite including in its molecule a liquid crystal material that expresses the following structure (H1) and a blue phase.

Another embodiment of the present invention is a liquid crystal display device using the above polymer / liquid crystal composite.

According to one embodiment of the present invention, a liquid crystal composition using a liquid crystalline monomer that also functions as a polymerization initiator can be provided.

The conceptual diagram explaining a liquid crystal element. 8A and 8B illustrate one embodiment of a liquid crystal display device. 3A and 3B each illustrate one embodiment of an electrode structure of a liquid crystal display device. FIG. 6 illustrates a liquid crystal display module. 10A and 10B each illustrate an electronic device. ¹ H-NMR chart of Dac-PrEPrEP-O6. Absorption spectrum of a solution of Dac-PrEPrEP-O6 in dichloromethane. 6 is a diagram illustrating a relationship between applied voltage and transmittance in the liquid crystal element of Example 2. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and various changes can be made in form and details without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below. Note that in the structures described below, the same portions and portions having similar functions are denoted by the same reference numerals in different drawings, and description thereof is not repeated.

In this specification and the like, a liquid crystal display device refers to an image display device, a display device, or a light source (including a lighting device). In addition, a connector, for example, a module with a FPC (Flexible Printed Circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package), a module with a printed wiring board at the end of TCP, or a display element with COG ( It is assumed that the liquid crystal display device includes all modules on which an IC (integrated circuit) is directly mounted by a chip on glass (Chip On Glass) method. The liquid crystal display device in this specification and the like includes all electronic devices using liquid crystal characteristics, and includes, for example, a liquid crystal electro-optical device having no display function.

(Embodiment 1)
In the present embodiment, a liquid crystal composition that exhibits a polymer-stabilized blue phase and a polymer / liquid crystal composite obtained by polymer stabilization treatment (polymerization) of the liquid crystal composition will be described.

The liquid crystal composition described in this embodiment includes a liquid crystal material that exhibits a blue phase, a non-liquid crystal monomer, and a liquid crystal monomer. In addition to these, a chiral agent may be included. The monomer includes a liquid crystal monomer and a non-liquid crystal monomer.

The blue phase is an optically isotropic phase that does not substantially scatter light. Examples of the liquid crystal material exhibiting a blue phase include nematic liquid crystalline compounds and smectic liquid crystalline compounds, and nematic liquid crystalline compounds are preferable. The nematic liquid crystalline compound is not particularly limited, and is a biphenyl compound, a terphenyl compound, a phenylcyclohexyl compound, a biphenylcyclohexyl compound, a phenylbicyclohexyl compound, a phenylbenzoate compound, or a cyclohexylphenylbenzoate compound. Compounds, phenyl benzoic acid phenyl compounds, bicyclohexyl carboxylic acid phenyl compounds, azomethine compounds, azo and azooxy compounds, stilbene compounds, bicyclohexyl compounds, phenyl pyrimidine compounds, biphenyl pyrimidine compounds, pyrimidine compounds, And biphenylethyne compounds.

A chiral agent is one that causes a twisted structure in a liquid crystal material. The amount of chiral agent added affects the diffraction wavelength of a liquid crystal material that exhibits a blue phase. Therefore, it is preferable to adjust the addition amount of the chiral agent so that the diffraction wavelength of the liquid crystal material expressing the blue phase is outside the visible region (380 to 750 nm). As the chiral agent, S-811 (manufactured by Merck), S-1011 (manufactured by Merck), 1,4: 3,6-dianhydro-2,5-bis [4- (n-hexyl-1-oxy) Benzoic acid] sorbitol (abbreviation: ISO- (6OBA) ₂ ) (manufactured by Midori Chemical Co., Ltd.) and the like can be appropriately selected and used.

Note that, in the liquid crystal composition, a configuration using a chiral agent having a strong twisting force has a stripe pattern derived from the orientation of the polymer / liquid crystal composite in the imaging data by the confocal laser scanning microscope, and the plurality of orientations of the liquid crystal composition. A characteristic texture (hereinafter sometimes simply referred to as a characteristic texture) in which at least two regions where the stripe pattern exists adjacent to each other without a boundary is present in a range corresponding to 15 μm × 15 μm is shown. This is a preferable structure because it can provide a polymer / liquid crystal composite with little light leakage.

A non-liquid crystalline monomer is a monomer that does not exhibit liquid crystallinity and can be polymerized by light and has a rod-like molecular structure (for example, an alkyl group, a cyano group, fluorine, etc. at the end of a biphenyl group or a biphenylcyclohexyl group) Refers to a monomer having no molecular structure or the like. Specific examples include monomers containing a polymerizable group such as an acryloyl group, a methacryloyl group, a vinyl group, and an epoxy group in the molecular structure, but are not limited thereto.

The liquid crystalline monomer is a monomer that exhibits liquid crystallinity and can be polymerized by light. The liquid crystalline monomer in the liquid crystal composition of one embodiment of the present invention is a liquid crystalline monomer that absorbs light with a wavelength of 320 nm or more, more preferably 365 nm or more in order to serve as a polymerization initiator.

Photopolymerization can be used for the polymer stabilization treatment (polymerization) of the liquid crystal composition of one embodiment of the present invention. Photopolymerization can be performed, for example, by irradiating with ultraviolet rays. However, among ultraviolet rays, ultraviolet rays having a wavelength of 365 nm or less, particularly 320 nm or less, may damage other materials in the liquid crystal composition, and are not suitable for polymer stabilization treatment (polymerization). Therefore, it is preferable to perform a polymer stabilization treatment (polymerization) by irradiating ultraviolet rays obtained by cutting ultraviolet rays having a wavelength of 365 nm or less, particularly 320 nm or less.

Therefore, the liquid crystalline monomer used for the liquid crystal composition of one embodiment of the present invention absorbs light of 320 nm or more, more preferably 365 nm or more, so that other materials in the liquid crystal composition are not damaged. In addition, a polymer stabilization treatment (polymerization) can be performed.

In order to absorb light of 320 nm or more, more preferably 365 nm or more, the liquid crystalline monomer in the liquid crystal composition of one embodiment of the present invention has a skeleton represented by the following general formula (A).

However, in general formula (A), X < ¹ >, X < ² > represents either hydrogen or a methyl group each independently.

Therefore, the liquid crystalline monomer in the liquid crystal composition of one embodiment of the present invention is represented by the following general formula (G1).

However, in General Formula (G1), R ¹ and R ² each independently represent either hydrogen or a methyl group. In the general formula (G1), X ¹ and X ² each independently represent either hydrogen or a methyl group. In general formula (G1), n and m are each independently an integer of 2 to 20.

The liquid crystalline monomer in the liquid crystal composition of one embodiment of the present invention is represented by the following general formula (G2).

However, in the general formula ^{(G2), R 1, R} 2 represents any one of the independently hydrogen or a methyl group. In general formula (G2), n and m are each independently an integer of 2 to 20.

The liquid crystalline monomer in the liquid crystal composition of one embodiment of the present invention is represented by the following general formula (G3).

However, in general formula (G3), R < ¹ >, R < ² > represents either hydrogen or a methyl group each independently.

Specific examples of the liquid crystalline monomer represented by General Formula (G1) include liquid crystalline monomers represented by Structural Formula (100) to Structural Formula (159). However, the present invention is not limited to these.

As a method for synthesizing a liquid crystalline monomer in the liquid crystal composition of one embodiment of the present invention, various reactions can be applied. For example, it can be synthesized by performing a synthesis reaction shown in the following synthesis methods 1 to 4.

≪Synthesis method 1≫
In this synthesis method, a synthesis method of the liquid crystalline monomer represented by the general formula (G1) according to the following reaction formulas (g-1) and (g-2) will be described.

A terephthalic acid monoester (compound (p3)) can be obtained by conducting an esterification reaction of a phenol derivative (compound (p1)) and a terephthalic acid derivative (compound (p2)). (Reaction formula (g-1)). In Reaction Formula (g-1), X ¹ and X ² each independently represent any ^one of hydrogen and a methyl group, R ¹ represents any ^one of hydrogen and a methyl group, and n is an integer of 2 to 20 Indicates.

Examples of the esterification reaction include an esterification reaction (addition / elimination reaction) by dehydration condensation using an acid catalyst. When the dehydration condensation reaction is performed, an acid catalyst such as sulfuric acid or para-toluenesulfonic acid can be used. Alternatively, esterification can be performed using a diimide compound such as 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide · hydrochloride (abbreviation: EDC) or dicyclohexylcarbodiimide (abbreviation: DCC). When EDC or DCC is used, it is preferable to use EDC because removal of by-products is easy. The synthesis of compound (p3) is not limited to these reactions.

Next, an esterification reaction between the terephthalic acid monoester (compound (p3)) obtained in the reaction formula (g-1) and a phenol derivative (compound (p4)) is performed to obtain the target general formula (G1 ) Can be obtained (Reaction Formula (g-2)). In Reaction Formula (g-2), R ¹ and R ² each independently represent either hydrogen or a methyl group. In the general formula (G1), X ¹ and X ² each independently represent either hydrogen or a methyl group. Moreover, in general formula (G1), n and m show the integer of 2 thru | or 20.

Examples of the esterification reaction include an esterification reaction (addition / elimination reaction) by dehydration condensation using an acid catalyst. When the dehydration condensation reaction is performed, an acid catalyst such as sulfuric acid or para-toluenesulfonic acid can be used. Alternatively, esterification can be performed using a diimide compound such as 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide · hydrochloride (abbreviation: EDC) or dicyclohexylcarbodiimide (abbreviation: DCC). When EDC or DCC is used, it is preferable to use EDC because removal of by-products is easy. Note that the synthesis of the general formula (G1) is not limited to these reactions.

Through the above, the liquid crystalline monomer in the liquid crystal composition of one embodiment of the present invention can be synthesized.

The liquid crystal composition which is one embodiment of the present invention includes the above materials. Then, by subjecting the liquid crystal composition to polymer stabilization treatment (polymerization), a polymer-stabilized blue phase can be expressed.

Photopolymerization can be used for the polymer stabilization treatment (polymerization) of the liquid crystal composition as described above, and for example, it can be performed by irradiating with ultraviolet rays. In addition, what is necessary is just to adjust suitably about the time to superpose | polymerize according to the material contained in a liquid-crystal composition.

The treatment temperature during the polymer stabilization treatment (polymerization) is preferably such that the resulting polymer / liquid crystal composite exhibits a polymer stabilized blue phase. More preferably, the temperature is such that the liquid crystal composition and the polymer / liquid crystal composite can maintain an isotropic or blue phase state. Moreover, even if a liquid crystal composition is an isotropic phase, what is necessary is just the temperature which can maintain the polymer / liquid crystal composite after a polymer stabilization process (polymerization) in the state of a blue phase. Further, the temperature may be changed during the polymer stabilization treatment (polymerization). In this case, the polymerization starts at a temperature at which the liquid crystal composition develops an isotropic phase or a blue phase, and the polymer / liquid crystal composite is blue. Any treatment temperature that exhibits a phase may be used.

By performing the polymerization, the liquid crystalline monomer and the non-liquid crystalline monomer in the liquid crystal composition are copolymerized to form a three-dimensional network having the following structure (H1) in the molecule. As a result, a polymer / liquid crystal composite containing the structure (H1) shown below and a liquid crystal material expressing a blue phase in the molecule is formed.

<< Synthesis Method 2 >>
In this synthesis method, a synthesis method of the liquid crystalline monomer represented by General Formula (G2) will be described.

The liquid crystalline monomer represented by General Formula (G2) is the same as Synthesis Method 1 except that X ¹ and X ² in General Formula (G1) and Reaction Formulas (g-1) and (g-2) are hydrogen. Can be synthesized.

In addition, by the polymer stabilization treatment (polymerization), the liquid crystalline monomer represented by the general formula (G2) and the non-liquid crystalline monomer in the liquid crystal composition are copolymerized to have the following structure (H2) in the molecule. A three-dimensional network is formed. As a result, a polymer / liquid crystal composite containing the structure (H2) of the following structural description and a liquid crystal material expressing a blue phase in the molecule is formed.

≪Synthesis method 3≫
In this synthesis method, a method for synthesizing the liquid crystalline monomer represented by General Formula (G3) will be described.

In the liquid crystal monomer represented by the general formula (G3), X ¹ and X ² in the general formula (G1), reaction formulas (g-1) and (g-2) are hydrogen, and n and m are 6. Except for the above, it can be synthesized in the same manner as in Synthesis Method 1.

In addition, by the polymer stabilization treatment (polymerization), the liquid crystalline monomer represented by the general formula (G3) and the non-liquid crystalline monomer in the liquid crystal composition are copolymerized to have the following structure (H3) in the molecule. A three-dimensional network is formed. As a result, a polymer / liquid crystal composite including the structure (H3) shown below and a liquid crystal material that develops a blue phase in the molecule is formed.

<< Synthesis Method 4 >>
In this synthesis method, a synthesis method of the liquid crystalline monomer represented by the structural formula (100) according to the following reaction formula (g-3) will be described.

By conducting an esterification reaction of 4- (6-acryloyloxy-n-hexyl-1-oxy) phenol with terephthalic acid, bis- [4- (6-acryloyloxy-n-hexyl-1) terephthalate is obtained. -Oxy) phenyl] (abbreviation: Dac-PrEPrEP-O6) is a reaction formula (g-3).

As the esterification reaction, the method described in Synthesis Example 1 can be applied.

Further, by the polymer stabilization treatment (polymerization), the liquid crystalline monomer represented by the structural formula (100) and the non-liquid crystalline monomer in the liquid crystal composition are copolymerized to have the following structure (H4) in the molecule. A three-dimensional network is formed. As a result, a polymer / liquid crystal composite including the structure (H4) shown below and a liquid crystal material that develops a blue phase in the molecule is formed.

By using the liquid crystal composition which is one embodiment of the present invention, a liquid crystal composition using a liquid crystalline monomer also serving as a polymerization initiator can be obtained. Therefore, it is not necessary to add a polymerization initiator, and the manufacturing process of the liquid crystal element can be reduced.

The structures, methods, and the like described in this embodiment can be combined as appropriate with any of the structures, methods, and the like described in the other embodiments.

(Embodiment 2)
In this embodiment, a liquid crystal element and a liquid crystal display device to which the liquid crystal composition described in the above embodiments is applied will be described with reference to drawings.

Examples of the liquid crystal element and the liquid crystal display device according to this embodiment are illustrated in FIGS.

Note that in this specification and the like, a liquid crystal element is an element that controls transmission or non-transmission of light by an optical modulation action of liquid crystal, and includes at least a pair of electrode layers and a liquid crystal composition sandwiched therebetween. Consists of. In this embodiment, the liquid crystal element includes the liquid crystal composition 208 capable of expressing the blue phase described in Embodiment 1 between at least a pair of electrode layers (the pixel electrode layer 230 and the common electrode layer 232 having different potentials). Have.

1A and 1B illustrate a liquid crystal in which a first substrate 200 and a second substrate 201 are arranged to face each other with a liquid crystal composition 208 expressing a blue phase interposed therebetween. It is a display device. The liquid crystal element and the liquid crystal display device in FIGS. 1A and 1B are examples in which the arrangement of the pixel electrode layer 230 and the common electrode layer 232 with respect to the liquid crystal composition 208 is different.

In the liquid crystal display device in FIG. 1A, a pixel electrode layer 230 and a common electrode layer 232 are provided adjacent to each other between a first substrate 200 and a liquid crystal composition 208. With the structure in FIG. 1A, a method can be used in which an electric field substantially parallel (that is, in a horizontal direction) to the substrate is generated and liquid crystal molecules are moved in a plane parallel to the substrate to control gradation. .

Such a structure in FIG. 1A can be preferably applied to the case where the above liquid crystal composition that expresses a blue phase, which is a liquid crystal composition according to one embodiment of the present invention, is used for the liquid crystal composition 208. .

A liquid crystal is controlled by forming an electric field between the pixel electrode layer 230 and the common electrode layer 232. Since a horizontal electric field is formed in the liquid crystal, the liquid crystal molecules can be controlled using the electric field. Since the liquid crystal composition that exhibits a blue phase can respond at high speed, the performance of the liquid crystal element and the liquid crystal display device can be improved. In addition, since the liquid crystal molecules aligned to exhibit a blue phase can be controlled in a direction parallel to the substrate, the viewing angle can be expanded.

For example, since a high-speed response is possible, an RGB light emitting diode (LED) or the like is arranged in the backlight device, and a continuous additive color mixing method (field sequential method) in which color display is performed by time division, or for left eye by time division. The present invention can be suitably applied to a three-dimensional display method using a shutter glasses method in which images and right-eye images are alternately viewed.

In the liquid crystal element and the liquid crystal display device in FIG. 1B, the pixel electrode layer 230 is provided on the first substrate 200 side and the common electrode layer 232 is provided on the second substrate 201 side with the liquid crystal composition 208 interposed therebetween. . With the structure in FIG. 1B, a method can be used in which a gray scale is controlled by generating an electric field substantially perpendicular to a substrate and moving liquid crystal molecules in a plane perpendicular to the substrate. Further, an alignment film 202 a and an alignment film 202 b may be provided between the liquid crystal composition 208 and the pixel electrode layer 230 and the common electrode layer 232. The liquid crystal composition according to one embodiment of the present invention can be used for liquid crystal elements with a variety of structures and liquid crystal display devices with a variety of display modes.

The distance between the pixel electrode layer 230 adjacent to the liquid crystal composition 208 and the common electrode layer 232 is determined by applying a predetermined voltage to the pixel electrode layer 230 and the common electrode layer 232, respectively. It is a distance to which the liquid crystal of the liquid crystal composition 208 interposed between the layers 232 responds. The voltage to be applied is appropriately controlled according to the distance.

The maximum value of the thickness (film thickness) of the liquid crystal composition 208 is preferably 1 μm or more and 20 μm or less.

As a method for injecting the liquid crystal composition 208, a dispensing method (a dropping method) or an injection method in which a liquid crystal is injected by using a capillary phenomenon after the first substrate 200 and the second substrate 201 are bonded to each other is used. Can do. Thereafter, the liquid crystal composition 208 is irradiated with light to perform polymerization.

Although not illustrated in FIGS. 1A and 1B, an optical film such as a polarizing plate, a retardation plate, or an antireflection film can be provided as appropriate. For example, circularly polarized light using a polarizing plate and a retardation plate may be used. Further, a backlight or the like can be used as the light source.

In this specification, a substrate on which a semiconductor element (eg, a transistor), a pixel electrode layer, and a common electrode layer are formed is referred to as an element substrate (first substrate), and faces the element substrate with a liquid crystal composition interposed therebetween. The substrate is referred to as a counter substrate (second substrate).

As a liquid crystal display device according to one embodiment of the present invention, a transmissive liquid crystal display device that performs display by transmitting light from a light source, a reflective liquid crystal display device that performs display by reflecting incident light, or transmission A transflective liquid crystal display device having both a mold and a reflection type can be provided.

In the case of a transmissive liquid crystal display device, a pixel electrode layer, a common electrode layer, a first substrate, a second substrate, other insulating films, a conductive film, and the like that exist in a pixel region through which light is transmitted are in a visible light wavelength region It is made translucent with respect to the light. In the liquid crystal display device having the structure of FIG. 1A, the pixel electrode layer and the common electrode layer are preferably light-transmitting. However, in the case of having an opening pattern, a non-light-transmitting material such as a metal film is used depending on the shape. Also good.

On the other hand, in the case of a reflective liquid crystal display device, a reflective member (such as a reflective film or substrate) that reflects light transmitted through the liquid crystal composition is provided on the side opposite to the viewing side with respect to the liquid crystal composition. Just do it. Therefore, the substrate, the insulating film, and the conductive film which are provided from the viewing side to the reflective member and transmit light are made transparent to light in the visible wavelength range. In this specification, translucency refers to a property of transmitting at least light in the visible wavelength region. In the liquid crystal display device having the structure of FIG. 1B, the pixel electrode layer or the common electrode layer on the side opposite to the viewing side can be made reflective and used as a reflective member.

The pixel electrode layer 230 and the common electrode layer 232 include indium tin oxide (ITO), indium zinc oxide obtained by mixing zinc oxide (ZnO) with indium oxide, conductive material obtained by mixing silicon oxide (SiO 2) with indium oxide, organic Indium, organic tin, indium oxide including tungsten oxide, indium zinc oxide including tungsten oxide, indium oxide including titanium oxide, indium tin oxide including titanium oxide, graphene, tungsten (W), molybdenum (Mo ), Zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), cobalt (Co), nickel (Ni), titanium (Ti), platinum (Pt) ), Metals such as aluminum (Al), copper (Cu), silver (Ag), or Alloys, or it can be formed using one or more species from the metal nitride thereof.

As the first substrate 200 and the second substrate 201, a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, a plastic substrate, or the like can be used.

By applying the liquid crystal composition of one embodiment of the present invention to a liquid crystal element or a liquid crystal display device, a liquid crystal element or a liquid crystal display device with reduced manufacturing steps can be obtained.

The structures, methods, and the like described in this embodiment can be combined as appropriate with any of the structures, methods, and the like described in the other embodiments.

(Embodiment 3)
As a liquid crystal display device according to one embodiment of the present invention, a passive matrix liquid crystal display device and an active matrix liquid crystal display device can be provided. In this embodiment, an example of an active matrix liquid crystal display device according to one embodiment of the present invention will be described with reference to FIGS.

FIG. 2A is a plan view of the liquid crystal display device and shows one pixel. FIG. 2B is a cross-sectional view taken along line X1-X2 in FIG.

In FIG. 2A, a plurality of source wiring layers (including the wiring layer 405a) are arranged in parallel to each other (extending in the vertical direction in the drawing) and separated from each other. The plurality of gate wiring layers (including the gate electrode layer 401) extend in a direction substantially orthogonal to the source wiring layer (the left-right direction in the drawing) and are arranged so as to be separated from each other. The common wiring layer 408 is disposed at a position adjacent to each of the plurality of gate wiring layers, and extends in a direction substantially parallel to the gate wiring layer, that is, a direction substantially orthogonal to the source wiring layer (the left-right direction in the drawing). ing. A substantially rectangular space is surrounded by the source wiring layer, the common wiring layer 408, and the gate wiring layer, and the pixel electrode layer and the common electrode layer of the liquid crystal display device are disposed in this space. The transistor 420 for driving the pixel electrode layer is arranged at the upper left corner in the drawing. A plurality of pixel electrode layers and transistors are arranged in a matrix.

In the liquid crystal display device in FIG. 2, the first electrode layer 447 electrically connected to the transistor 420 functions as a pixel electrode layer, and the second electrode layer 446 electrically connected to the common wiring layer 408 is a common electrode layer. Function as. Note that a capacitor is formed by the first electrode layer and the common wiring layer. The common electrode layer can be operated in a floating state (electrically isolated state), but may be set to a fixed potential, preferably a level at which no flicker occurs in the vicinity of an intermediate potential of an image signal sent as data.

A method can be used in which an electric field substantially parallel (that is, in a horizontal direction) is generated on the substrate and liquid crystal molecules are moved in a plane parallel to the substrate to control gradation. As such a system, an electrode configuration used in the IPS mode as shown in FIGS. 2 and 3 can be applied.

The horizontal electric field mode shown in the IPS mode or the like includes a first electrode layer (for example, a pixel electrode layer whose voltage is controlled for each pixel) and a second electrode layer (for example, all pixels) having an opening pattern below the liquid crystal composition. A common electrode layer to which a common voltage is supplied. Accordingly, a first electrode layer 447 and a second electrode layer 446, one of which is a pixel electrode layer and the other is a common electrode layer, are formed over the first substrate 441, and at least the first electrode layer and the second electrode layer 446 are formed. One of the two electrode layers is formed on the interlayer film. The first electrode layer 447 and the second electrode layer 446 have various opening patterns instead of a planar shape, and include bent portions and branched comb-teeth shapes. The first electrode layer 447 and the second electrode layer 446 are arranged in the same shape and do not overlap with each other in order to generate an electric field between the electrodes.

Alternatively, an electrode structure used in an FFS mode may be used as the first electrode layer 447 and the second electrode layer 446. The transverse electric field mode shown in the FFS mode is a first electrode layer having an opening pattern below the liquid crystal composition (for example, a pixel electrode layer in which voltage is controlled for each pixel) and a flat plate below the opening pattern. A second electrode layer (for example, a common electrode layer to which a common voltage is supplied to all pixels) is disposed. In this case, a first electrode layer and a second electrode layer, one of which is a pixel electrode layer and the other is a common electrode layer, are formed over the first substrate 441. The pixel electrode layer, the common electrode layer, Are arranged so as to be laminated via an insulating film (or an interlayer insulating layer). One of the pixel electrode layer and the common electrode layer is formed below the insulating film (or interlayer insulating layer) and has a flat plate shape, and the other is formed above the insulating film (or interlayer insulating layer), and It has various opening patterns and has a shape including a bent portion and a branched comb-teeth shape. The first electrode layer 447 and the second electrode layer 446 are arranged in the same shape and do not overlap with each other in order to generate an electric field between the electrodes.

As the liquid crystal composition 444, the liquid crystal composition described in Embodiment 1 is used. In addition, the liquid crystal composition 444 may include an organic resin. In this embodiment, as the liquid crystal composition 444, the liquid crystal composition capable of expressing the blue phase described in Embodiment 1 is used, and the blue phase is expressed by polymer stabilization treatment (the blue phase is changed). (Also referred to as a state exhibiting or a blue phase).

By forming an electric field between the first electrode layer 447 that is a pixel electrode layer and the second electrode layer 446 that is a common electrode layer, the liquid crystal of the liquid crystal composition 444 is controlled. Since a horizontal electric field is formed in the liquid crystal, the liquid crystal molecules can be controlled using the electric field. Since the liquid crystal molecules aligned to exhibit a blue phase can be controlled in a direction parallel to the substrate, the viewing angle is widened.

Another example of the first electrode layer 447 and the second electrode layer 446 is illustrated in FIG. As shown in the top views of FIGS. 3A to 3D, the first electrode layers 447a to 447d and the second electrode layers 446a to 446d are formed to be staggered, and FIG. In FIG. 3B, the first electrode layer 447a and the second electrode layer 446a have wavy shapes, and in FIG. 3B, the first electrode layer 447b and the second electrode layer 446b have concentric openings. In FIG. 3C, the first electrode layer 447c and the second electrode layer 446c are comb-shaped and partly overlapped. In FIG. 3D, the first electrode layer 447d is formed. The second electrode layer 446d is comb-shaped and has a shape in which the electrodes are engaged with each other. 3A to 3C, when the first electrode layers 447a, 447b, and 447c overlap with the second electrode layers 446a, 446b, and 446c, the first electrode layer 447 and An insulating film is formed between the second electrode layer 446 and a first electrode layer 447 and a second electrode layer 446 are formed over different films.

Note that the first electrode layer 447 and the second electrode layer 446 have a shape having an opening pattern, and thus are illustrated as a plurality of divided electrode layers in the cross-sectional view of FIG. The same applies to the other drawings of this specification.

The transistor 420 is an inverted staggered thin film transistor which is formed over a first substrate 441 which is a substrate having an insulating surface and serves as a gate electrode layer 401, a gate insulating layer 402, a semiconductor layer 403, and a source electrode layer or a drain electrode layer. It includes wiring layers 405a and 405b that function.

There is no particular limitation on the structure of the transistor that can be applied to the liquid crystal display device disclosed in this specification. For example, a staggered type or a planar type with a top gate structure or a bottom gate structure can be used. The transistor may have a single gate structure in which one channel formation region is formed, a double gate structure in which two channel formation regions are formed, or a triple gate structure in which three channel formation regions are formed. Alternatively, a dual gate type having two gate electrode layers arranged above and below the channel region with a gate insulating layer interposed therebetween may be used.

An insulating film 407 and an insulating film 409 which cover the transistor 420 and are in contact with the semiconductor layer 403 are provided, and an interlayer film 413 is stacked over the insulating film 409.

The first substrate 441 and the second substrate 442 which is a counter substrate are fixed to each other with a sealant with the liquid crystal composition 444 interposed therebetween. As a method for forming the liquid crystal composition 444, a dispensing method (a dropping method) or an injection method in which liquid crystal is injected using a capillary phenomenon after the first substrate 441 and the second substrate 442 are bonded to each other is used. Can do.

As the sealing material, it is typically preferable to use a visible light curable resin, an ultraviolet curable resin, or a thermosetting resin. Typically, an acrylic resin, an epoxy resin, an amine resin, or the like can be used. Further, it may contain a light (typically ultraviolet) polymerization initiator, a thermosetting agent, a filler, and a coupling agent.

The sealing material may be cured by a light irradiation process of polymer stabilization treatment, for example, when a photocurable resin such as ultraviolet rays is used for the sealing material and a liquid crystal composition is formed by a dropping method.

In this embodiment, a polarizing plate 443a is provided outside the first substrate 441 (on the side opposite to the liquid crystal composition 444), and a polarizing plate 443b is provided outside the second substrate 442 (on the side opposite to the liquid crystal composition 444). . In addition to the polarizing plate, an optical film such as a retardation plate or an antireflection film may be provided. For example, circularly polarized light using a polarizing plate and a retardation plate may be used. Through the above steps, a liquid crystal display device can be completed.

Although not shown, a backlight, a sidelight, or the like may be used as the light source. The light source is irradiated so as to transmit from the first substrate 441 side which is an element substrate to the second substrate 442 which is the viewing side.

The first electrode layer 447 and the second electrode layer 446 include indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, A light-transmitting conductive material such as ITO, indium zinc oxide, indium tin oxide to which silicon oxide is added, or graphene can be used.

The first electrode layer 447 and the second electrode layer 446 are formed using tungsten (W), molybdenum (Mo), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta). ), Chromium (Cr), cobalt (Co), nickel (Ni), titanium (Ti), platinum (Pt), aluminum (Al), copper (Cu), silver (Ag), or an alloy thereof, or The metal nitride can be formed using one or more kinds.

Alternatively, the first electrode layer 447 and the second electrode layer 446 can be formed using a conductive composition including a conductive high molecule (also referred to as a conductive polymer).

An insulating film serving as a base film may be provided between the first substrate 441 and the gate electrode layer 401. The base film has a function of preventing diffusion of an impurity element from the first substrate 441 and is formed using one or a plurality of films selected from a silicon nitride film, a silicon oxide film, a silicon nitride oxide film, and a silicon oxynitride film. A single layer or a stacked structure can be used. The material of the gate electrode layer 401 can be formed using a metal material such as molybdenum, titanium, chromium, tantalum, tungsten, aluminum, copper, neodymium, or scandium, or an alloy material containing any of these materials as its main component. As the gate electrode layer 401, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus, or a silicide film such as nickel silicide may be used. The gate electrode layer 401 may have a single-layer structure or a stacked structure. Note that when a conductive film having a light-blocking property is used for the gate electrode layer 401, light from the backlight (light which enters from the first substrate 441) can be prevented from entering the semiconductor layer 403.

The gate insulating layer 402 is formed using a silicon oxide film, a gallium oxide film, an aluminum oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum oxynitride film, a silicon nitride oxide film, or the like by a plasma CVD method, a sputtering method, or the like. Can be formed. Alternatively, the material of the gate insulating layer 402 may be hafnium oxide, yttrium oxide, lanthanum oxide, hafnium silicate (HfSi _x O _y (x> 0, y> 0)), hafnium aluminate (HfAl _x O _y (x> 0, y > 0)), high-k materials such as nitrogen-added hafnium silicate and nitrogen-added hafnium aluminate may be used. The gate leakage current can be reduced by using these high-k materials. Note that the gate insulating layer 402 may have a single-layer structure or a stacked structure.

The material used for the semiconductor layer 403 is not particularly limited and may be set as appropriate depending on characteristics required for the transistor 420. Examples of materials that can be used for the semiconductor layer 403 are described.

As a material for forming the semiconductor layer 403, for example, amorphous silicon, polycrystalline silicon, single crystal silicon, or the like can be used. For the semiconductor layer 108, an oxide semiconductor may be used. The oxide semiconductor is an In-M-Zn oxide containing at least indium (In), zinc (Zn), and M (metal such as Al, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf). It is preferable to include the indicated layer. Or it is preferable that both In and Zn are included.

For example, as an oxide semiconductor, indium oxide, tin oxide, zinc oxide, In—Zn oxide, Sn—Zn oxide, Al—Zn oxide, Zn—Mg oxide, Sn—Mg oxide, In—Mg oxide In-Ga oxide, In-Ga-Zn oxide, In-Al-Zn oxide, In-Sn-Zn oxide, Sn-Ga-Zn oxide, Al-Ga-Zn oxide, Sn- Al—Zn oxide, In—Hf—Zn oxide, In—La—Zn oxide, In—Ce—Zn oxide, In—Pr—Zn oxide, In—Nd—Zn oxide, In—Sm— Zn oxide, In-Eu-Zn oxide, In-Gd-Zn oxide, In-Tb-Zn oxide, In-Dy-Zn oxide, In-Ho-Zn oxide, In-Er-Zn oxide , In-Tm-Zn oxide, In-Yb-Zn oxidation In-Lu-Zn oxide, In-Sn-Ga-Zn oxide, In-Hf-Ga-Zn oxide, In-Al-Ga-Zn oxide, In-Sn-Al-Zn oxide, In -Sn-Hf-Zn oxide and In-Hf-Al-Zn oxide can be used.

Note that here, for example, an In—Ga—Zn oxide means an oxide containing In, Ga, and Zn as its main components, and there is no limitation on the ratio of In, Ga, and Zn. Moreover, metal elements other than In, Ga, and Zn may be contained.

Note that the semiconductor layer 403 is a semiconductor layer which is etched only partly and has a groove (concave portion).

As a material of the wiring layers 405a and 405b functioning as the source electrode layer or the drain electrode layer, an element selected from Al, Cr, Ta, Ti, Mo, and W, or an alloy containing the above-described element as a component, or the above-described element is used. Examples include alloy films combining elements. In the case where heat treatment is performed, it is preferable that the conductive film has heat resistance enough to withstand the heat treatment. For example, Al alone is inferior in heat resistance and easily corroded, so it is formed in combination with a heat resistant conductive material. The heat-resistant conductive material combined with Al is an element selected from titanium (Ti), tantalum (Ta), tungsten (W), molybdenum (Mo), chromium (Cr), neodymium (Nd), and scandium (Sc). Or an alloy containing the above elements as a component, an alloy film combining the above elements, or a nitride containing the above elements as a component.

As the insulating film 407 and the insulating film 409 which cover the transistor 420, an inorganic insulating film or an organic insulating film formed by a dry method or a wet method can be used. For example, a silicon nitride film, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, a tantalum oxide film, or the like obtained by a CVD method, a sputtering method, or the like can be used. Alternatively, an organic material such as polyimide, acrylic, benzocyclobutene resin, polyamide, or epoxy can be used. In addition to the above organic materials, a low dielectric constant material (low-k material), a siloxane resin, PSG (phosphosilicate glass), BPSG (boron phosphosilicate glass), or the like can be used. Alternatively, a gallium oxide film may be used as the insulating film 407.

Note that the insulating film 407 and the insulating film 409 may be formed by stacking a plurality of insulating films formed using these materials. For example, an organic resin film may be stacked on the inorganic insulating film.

As described above, by applying the liquid crystal composition described in Embodiment 1 to a liquid crystal display device, a liquid crystal display device in which a manufacturing process is reduced can be provided.

In addition, the liquid crystal element including the liquid crystal composition exhibiting a blue phase described in Embodiment Mode 1 can respond at high speed, so that the performance of the liquid crystal display device can be improved.

The structures, methods, and the like described in this embodiment can be combined as appropriate with any of the structures, methods, and the like described in the other embodiments.

(Embodiment 4)
In this embodiment, a liquid crystal display device including the liquid crystal composition described in the above embodiment will be described. The liquid crystal display device includes a transistor in a pixel portion and further in a driver circuit. In addition, part or the whole of the driver circuit can be formed over the same substrate as the pixel portion by using a transistor, so that a system-on-panel can be formed.

A liquid crystal display device includes a liquid crystal element (also referred to as a liquid crystal display element) as a display element.

Further, the liquid crystal display device includes a panel in which the display element is sealed, and a module in which an IC or the like including a controller is mounted on the panel. Furthermore, in the process of manufacturing the liquid crystal display device, an element substrate corresponding to one embodiment before the display element is completed, the element substrate includes means for supplying current to the display element in each of the plurality of pixels. . Specifically, the element substrate may be in a state where only the pixel electrode of the display element is formed, or after the conductive film to be the pixel electrode is formed, the pixel electrode is formed by etching. The previous state may be used, and all forms are applicable.

The appearance and a cross section of a liquid crystal display panel, which is an embodiment of a liquid crystal display device, will be described with reference to FIGS. 4A1 and 4A2 illustrate that the transistor 4010, the transistor 4011, and the liquid crystal element 4013 which are formed over the first substrate 4001 are sealed with a sealant 4005 between the second substrate 4006. 4B is a top view of the panel, and FIG. 4B corresponds to a cross-sectional view taken along line MN in FIGS. 4A1 and 4A2.

A sealant 4005 is provided so as to surround the pixel portion 4002 provided over the first substrate 4001 and the scan line driver circuit 4004. A second substrate 4006 is provided over the pixel portion 4002 and the scan line driver circuit 4004. Therefore, the pixel portion 4002 and the scan line driver circuit 4004 are sealed together with the liquid crystal composition 4008 by the first substrate 4001, the sealant 4005, and the second substrate 4006.

4A1 is formed using a single crystal semiconductor film or a polycrystalline semiconductor film over a separately prepared substrate in a region different from the region surrounded by the sealant 4005 over the first substrate 4001. A signal line driver circuit 4003 is mounted. 4A2 illustrates an example in which part of the signal line driver circuit is formed using a transistor provided over the first substrate 4001. The signal line driver circuit 4003b is formed over the first substrate 4001. In addition, a signal line driver circuit 4003a formed of a single crystal semiconductor film or a polycrystalline semiconductor film is mounted on a separately prepared substrate.

Note that a connection method of a driver circuit which is separately formed is not particularly limited, and a COG method, a wire bonding method, a TAB method, or the like can be used. 4A1 illustrates an example in which the signal line driver circuit 4003 is mounted by a COG method, and FIG. 4A2 illustrates an example in which the signal line driver circuit 4003 is mounted by a TAB method.

The pixel portion 4002 and the scan line driver circuit 4004 provided over the first substrate 4001 include a plurality of transistors. In FIG. 4B, the transistor 4010 included in the pixel portion 4002 and the scan line driver circuit 4004 are scanned. The transistor 4011 included in the line driver circuit 4004 is illustrated. An insulating layer 4020 and an interlayer film 4021 are provided over the transistors 4010 and 4011.

The transistor described in Embodiment 4 can be applied to the transistors 4010 and 4011.

Alternatively, a conductive layer may be provided over the interlayer film 4021 or the insulating layer 4020 so as to overlap with a channel formation region of the semiconductor layer of the transistor 4011 for the driver circuit. The potential of the conductive layer may be the same as or different from that of the gate electrode layer of the transistor 4011, and the conductive layer can function as a second gate electrode layer. Further, the potential of the conductive layer may be GND, 0 V, or the conductive layer may be in a floating state.

In addition, a pixel electrode layer 4030 and a common electrode layer 4031 are formed over the interlayer film 4021, and the pixel electrode layer 4030 is electrically connected to the transistor 4010. The liquid crystal element 4013 includes a pixel electrode layer 4030, a common electrode layer 4031, and a liquid crystal composition 4008. Note that a polarizing plate 4032a and a polarizing plate 4032b are provided outside the first substrate 4001 and the second substrate 4006, respectively.

As the liquid crystal composition 4008, the liquid crystal composition described in Embodiment 1 is used. The pixel electrode layer 4030 and the common electrode layer 4031 can have the structure of the pixel electrode layer and the common electrode layer as described in the above embodiment modes.

In this embodiment mode, the liquid crystal composition 4008 uses a liquid crystal composition that expresses a blue phase, and is in a state where a blue phase is expressed (a state that exhibits a blue phase or a state that exhibits a blue phase) by polymer stabilization treatment. It is provided in the liquid crystal display device. Therefore, in this embodiment mode, the pixel electrode layer 4030 and the common electrode layer 4031 as illustrated in FIGS. 1A and 3 have a shape having an opening pattern.

By forming an electric field between the pixel electrode layer 4030 and the common electrode layer 4031, the liquid crystal of the liquid crystal composition 4008 is controlled. Since a horizontal electric field is formed in the liquid crystal, the liquid crystal molecules can be controlled using the electric field. Since the liquid crystal molecules aligned to exhibit a blue phase can be controlled in a direction parallel to the substrate, the viewing angle is widened.

Note that the first substrate 4001 and the second substrate 4006 can be formed using light-transmitting glass, plastic, or the like. As the plastic, an FRP (Fiberglass-Reinforced Plastics) plate, a PVF (polyvinyl fluoride) film, a polyester film, or an acrylic resin film can be used. A sheet having a structure in which an aluminum foil is sandwiched between PVF films or polyester films can also be used.

A columnar spacer 4035 is a columnar spacer obtained by selectively etching an insulating film and is provided to control the film thickness (cell gap) of the liquid crystal composition 4008. A spherical spacer may be used. In a liquid crystal display device using the liquid crystal composition 4008, the cell gap which is the thickness of the liquid crystal composition is preferably 1 μm or more and 20 μm or less. In the present specification, the thickness of the cell gap is the maximum value of the thickness (film thickness) of the liquid crystal composition.

Although FIG. 4 shows an example of a transmissive liquid crystal display device, this embodiment can be applied to a transflective liquid crystal display device or a reflective liquid crystal display device.

4 shows an example in which a polarizing plate is provided on the outer side (viewing side) of the substrate, the polarizing plate may be provided on the inner side of the substrate. What is necessary is just to set suitably according to the material and preparation process conditions of a polarizing plate. Further, a light shielding layer functioning as a black matrix may be provided.

A color filter layer or a light shielding layer may be formed as part of the interlayer film 4021. FIG. 4 illustrates an example in which a light-blocking layer 4034 is provided on the second substrate 4006 side so as to cover the upper portions of the transistors 4010 and 4011. By providing the light-blocking layer 4034, the effects of improving contrast and stabilizing the transistor can be further increased.

The transistor may be covered with an insulating layer 4020 functioning as a protective film, but is not particularly limited.

Note that the protective film is for preventing entry of contaminant impurities such as organic substances, metal substances, and water vapor in the atmosphere, and a dense film is preferable. The protective film is formed by a sputtering method using a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon nitride oxide film, an aluminum oxide film, an aluminum nitride film, an aluminum oxynitride film, or an aluminum nitride oxide film, Alternatively, a stacked layer may be formed.

In the case where a light-transmitting insulating layer is further formed as the planarizing insulating film, a heat-resistant organic material such as polyimide, acrylic, benzocyclobutene resin, polyamide, or epoxy can be used. In addition to the above organic materials, a low dielectric constant material (low-k material), a siloxane resin, PSG (phosphosilicate glass), BPSG (boron phosphosilicate glass), or the like can be used. Note that the insulating layer may be formed by stacking a plurality of insulating films formed using these materials.

The method of forming the insulating layer to be stacked is not particularly limited, and depending on the material, sputtering method, spin coating, dipping method, spray coating method, droplet discharge method (inkjet method, etc.), printing method (screen printing, offset) Printing), roll coat, curtain coat, knife coat and the like.

The pixel electrode layer 4030 and the common electrode layer 4031 include indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, ITO, and indium zinc oxide. Further, a light-transmitting conductive material such as an oxide, indium tin oxide to which silicon oxide is added, or graphene can be used.

The pixel electrode layer 4030 and the common electrode layer 4031 include tungsten (W), molybdenum (Mo), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr ), Cobalt (Co), nickel (Ni), titanium (Ti), platinum (Pt), aluminum (Al), copper (Cu), silver (Ag), or a metal thereof, an alloy thereof, or a metal nitride thereof One or a plurality of types can be used.

The pixel electrode layer 4030 and the common electrode layer 4031 can be formed using a conductive composition including a conductive high molecule (also referred to as a conductive polymer).

In addition, a variety of signals and potentials are supplied to the signal line driver circuit 4003 which is formed separately, the scan line driver circuit 4004, or the pixel portion 4002 from an FPC 4018.

Further, since the transistor is easily broken by static electricity or the like, it is preferable to provide a protective circuit for protecting the driver circuit over the same substrate for the gate line or the source line. The protection circuit is preferably configured using a non-linear element.

In FIG. 4, the connection terminal electrode 4015 is formed using the same conductive film as the pixel electrode layer 4030, and the terminal electrode 4016 is formed using the same conductive film as the source and drain electrode layers of the transistors 4010 and 4011.

The connection terminal electrode 4015 is electrically connected to a terminal included in the FPC 4018 through an anisotropic conductive film 4019.

FIG. 4 illustrates an example in which the signal line driver circuit 4003 is separately formed and mounted on the first substrate 4001; however, the present invention is not limited to this structure. The scan line driver circuit may be separately formed and then mounted, or only part of the signal line driver circuit or part of the scan line driver circuit may be separately formed and then mounted.

As described above, by applying the liquid crystal composition described in Embodiment 1 to a liquid crystal display device, a liquid crystal display device in which a manufacturing process is reduced can be provided.

In addition, the liquid crystal element including the liquid crystal composition exhibiting a blue phase described in Embodiment Mode 1 can respond at high speed, so that the performance of the liquid crystal display device can be improved.

The structures, methods, and the like described in this embodiment can be combined as appropriate with any of the structures, methods, and the like described in the other embodiments.

(Embodiment 5)
In this embodiment, examples of electronic devices using a liquid crystal display device to which one embodiment of the present invention is applied will be described with reference to FIGS.

The electronic device of this embodiment includes the liquid crystal display device of one embodiment of the present invention in the display portion.

As an electronic device to which a liquid crystal display device is applied, for example, a television device (also referred to as a television or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (a mobile phone, Large-sized game machines such as portable telephones, portable game machines, portable information terminals, sound reproduction apparatuses, and pachinko machines. Specific examples of these electronic devices are shown in FIGS.

FIG. 5A illustrates an example of a television device. In the television device 7100, a display portion 7102 is incorporated in a housing 7101. The display portion 7102 can display an image. A liquid crystal display device to which one embodiment of the present invention is applied can be used for the display portion 7102. Here, a structure in which the housing 7101 is supported by a stand 7103 is shown.

The television device 7100 can be operated with an operation switch included in the housing 7101 or a separate remote controller 7111. Channels and volume can be operated with operation keys included in the remote controller 7111, and an image displayed on the display portion 7102 can be operated. Further, the remote controller 7111 may be provided with a display unit that displays information output from the remote controller 7111.

Note that the television device 7100 is provided with a receiver, a modem, and the like. General TV broadcasts can be received by a receiver, and connected to a wired or wireless communication network via a modem, so that it can be unidirectional (sender to receiver) or bidirectional (sender and receiver). It is also possible to perform information communication between each other or between recipients).

FIG. 5B illustrates an example of a computer. A computer 7200 includes a main body 7201, a housing 7202, a display portion 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. Note that the computer is manufactured using the liquid crystal display device of one embodiment of the present invention for the display portion 7203.

FIG. 5C illustrates an example of a portable game machine. The portable game machine 7300 includes two housings, a housing 7301a and a housing 7301b, which are connected with a joint portion 7302 so that the portable game machine 7300 can be opened and closed. A display portion 7303a is incorporated in the housing 7301a, and a display portion 7303b is incorporated in the housing 7301b. 5C includes a speaker portion 7304, a recording medium insertion portion 7305, operation keys 7306, a connection terminal 7307, and a sensor 7308 (force, displacement, position, speed, acceleration, angular velocity, rotation speed). , Distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, smell, or infrared) LED lamp, microphone, etc. are provided. Needless to say, the structure of the portable game machine is not limited to the above, and the liquid crystal display device of one embodiment of the present invention may be used for at least one of the display portion 7303a and the housing 7301b, or one of the other accessories. Can be provided as appropriate. The portable game machine shown in FIG. 5C shares the information by reading a program or data recorded in a recording medium and displaying the program or data on a display unit or by performing wireless communication with another portable game machine. It has a function. Note that the function of the portable game machine illustrated in FIG. 5C is not limited to this, and the portable game machine can have a variety of functions.

FIG. 5D illustrates an example of a mobile phone. A mobile phone 7400 is provided with a display portion 7402 incorporated in a housing 7401, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone 7400 is manufactured using the liquid crystal display device of one embodiment of the present invention for the display portion 7402.

A cellular phone 7400 illustrated in FIG. 5D can input information by touching the display portion 7402 with a finger or the like. In addition, operations such as making a call or creating a mail can be performed by touching the display portion 7402 with a finger or the like.

There are mainly three screen modes of the display portion 7402. The first mode is a display mode mainly for displaying an image. The first is a display mode mainly for displaying images, and the second is an input mode mainly for inputting information such as characters. The third is a display + input mode in which the display mode and the input mode are mixed.

For example, when making a call or creating a mail, the display portion 7402 may be set to a character input mode mainly for inputting characters, and an operation for inputting characters displayed on the screen may be performed.

In addition, by providing a detection device having a sensor for detecting inclination, such as a gyro sensor or an acceleration sensor, in the mobile phone 7400, the orientation (vertical or horizontal) of the mobile phone 7400 is determined, and the screen of the display portion 7402 The display can be switched automatically.

Further, the screen mode is switched by touching the display portion 7402 or operating the operation button 7403 of the housing 7401. Further, switching can be performed depending on the type of image displayed on the display portion 7402. For example, if the image signal to be displayed on the display unit is moving image data, the mode is switched to the display mode, and if it is text data, the mode is switched to the input mode.

Further, in the input mode, when a signal detected by the optical sensor of the display unit 7402 is detected and there is no input by a touch operation of the display unit 7402 for a certain period, the screen mode is switched from the input mode to the display mode. You may control.

The display portion 7402 can function as an image sensor. For example, personal authentication can be performed by touching the display portion 7402 with a palm or a finger and capturing an image of a palm print, a fingerprint, or the like. In addition, if a backlight that emits near-infrared light or a sensing light source that emits near-infrared light is used for the display portion, finger veins, palm veins, and the like can be imaged.

FIG. 5E illustrates an example of a tablet terminal that can be folded in half (opened state). The tablet terminal 7500 includes a housing 7501a, a housing 7501b, a display portion 7502a, and a display portion 7502b. The housing 7501a and the housing 7501b are connected by a shaft portion 7503, and an opening / closing operation can be performed using the shaft portion 7503 as an axis. The housing 7501a includes a power source 7504, operation keys 7505, a speaker 7506, and the like. Note that the tablet terminal 7500 is manufactured using the liquid crystal display device of one embodiment of the present invention for either or both of the display portion 7502a and the display portion 7502b.

At least part of the display portion 7502a and the display portion 7502b can be a touch panel region, and data can be input by touching displayed operation keys. For example, keyboard buttons can be displayed on the entire surface of the display portion 7502a to form a touch panel, and the display portion 7502b can be used as a display screen.

This embodiment can be combined with any of the other embodiments as appropriate.

In this example, bis- [4- (6-acryloyloxy) terephthalate, which is a liquid crystalline monomer contained in the liquid crystal composition that is one embodiment of the present invention and represented by the chemical formula (100) in Embodiment 1, is used. A synthesis example of (n-hexyl-1-oxy) phenyl] (abbreviation: Dac-PrEPrEP-O6) is illustrated. The structural formula of Dac-PrEPrEP-O6 is shown below.

≪Synthesis example≫
In a 500 mL eggplant flask, 2.0 g (7.6 mmol) of 4- (6-acryloyloxy-n-hexyl-1-oxy) phenol, 0.60 g (3.6 mmol) of terephthalic acid, 0.28 g ( 2.3 mmol) 4-dimethylaminopyridine (DMAP), 1.5 g (7.6 mmol) 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), 100 mL N, N -Dimethylformamide (DMF) was added and the solution was stirred under air at room temperature for 27 hours. After confirming the completion of the reaction by thin layer chromatography (TLC), the obtained solution was concentrated, chloroform, saturated aqueous sodium hydrogen carbonate solution and saturated brine were added, the organic layer was taken out, The layer was extracted 3 times with chloroform. The organic layer and the extract were combined, washed with saturated brine, dried over magnesium sulfate, and the mixture was separated by gravity filtration. The filtrate was concentrated, and the resulting solution was purified by silica gel column chromatography (developing solvent: chloroform) to obtain a white solid substance. The obtained white solid material was further purified by high performance liquid chromatography (HPLC) to obtain 0.5 g of white solid in a yield of 22%. This synthesis scheme is shown in (a-1).

≪NMR≫
¹ H NMR data of the obtained substance is shown below. Further, the ¹ H NMR chart is shown in FIG.

¹ H NMR (CDCl ₃ , 300 MHz): δ (ppm) = 1.45-1.59 (m, 8H), 1.68-1.87 (m, 8H), 3.98 (t, J = 6) .3 Hz, 4H), 4.18 (t, J = 6.6 Hz, 4H), 5.82 (dd, J1 = 10.4 Hz, J2 = 1.7 Hz, 2H), 6.13 (dd, J1 = 10.5 Hz, J2 = 17.4 Hz, 2H), 6.41 (dd, J1 = 1.4 Hz, J2 = 17.6 Hz, 2H), 6.94 (d, J = 6.9 Hz, 4H), 7 .15 (d, J = 9.3 Hz, 4H), 8.32 (s, 4H).

≪UV absorption≫
Next, an ultraviolet-visible absorption spectrum (hereinafter, simply referred to as “absorption spectrum”) of Dac-PrEPrEP-O6 was measured. The measurement results are shown in FIGS. 7 (A) and (B). FIG. 7B is an enlarged view of the light absorption intensity on the vertical axis of FIG. For the measurement of the absorption spectrum, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. FIG. 7 shows an absorption spectrum obtained by subtracting a spectrum obtained by placing only dichloromethane in a quartz cell from a spectrum obtained by placing a dichloromethane solution of Dac-PrEPrEP-O6 in a quartz cell.

In the absorption spectrum, an absorption peak was observed at 243 nm. As shown in FIGS. 7A and 7B, it was found that the absorption edge of Dac-PrEPrEP-O6 has a wavelength longer than 320 nm. It was also found that the absorption edge of Dac-PrEPrEP-O6 has a wavelength longer than 365 nm, particularly as shown in FIG.

In this example, two types of liquid crystal compositions as a liquid crystal composition which is one embodiment of the present invention and one type of liquid crystal composition as a comparative example are manufactured, and the characteristics of a liquid crystal element manufactured using the liquid crystal compositions are evaluated.

Table 1 shows the structure of the liquid crystal composition used in the liquid crystal element 1, the liquid crystal element 2, and the comparative liquid crystal element manufactured in this example. In Table 1, the mixing ratio is expressed as a weight ratio.

In the liquid crystal element 1, the liquid crystal element 2, and the comparative liquid crystal element of this example, mixed liquid crystal E-8 (manufactured by LCC Co., Ltd.), 4- (trans-4-n-propylcyclohexyl) is used as a liquid crystal material exhibiting a blue phase. -3 ′, 4′-difluoro-1,1′-biphenyl (abbreviation: CPP-3FF) (manufactured by Taidate Polymer Industries), and 4-cyano-3-fluorophenyl 4-n-pentylbenzoate (abbreviation) : PEP-5CNF) (manufactured by Taidate Polymer Industries Co., Ltd.). Further, 1,4: 3,6-dianhydro-2,5-bis [4- (n-hexyl-1-oxy) benzoic acid] sorbitol (abbreviation: ISO- (6OBA) ₂ ) (Midori Chemical Co., Ltd.) as a chiral agent Company). Further, dodecyl methacrylate (abbreviation: DMeAc) was used as the non-liquid crystalline monomer.

As the liquid crystal monomer, in the liquid crystal element 1, bis- [4- (6-acryloyloxy-n-hexyl-1-oxy) phenyl] terephthalate prepared in Example 1 (abbreviation: Dac-PrEPrEP-O6) Was used. As the liquid crystal monomer, in the liquid crystal element 2, Dac-PrEPrEP-O6 prepared in Example 1 and 1,4-bis [4- (6-acryloyloxy-n-hexyl-1-oxy) benzoyloxy]- 2-methylbenzene (abbreviation: RM257-O6) was used. As a liquid crystal monomer, RM257-O6 was used in the comparative liquid crystal element.

As a polymerization initiator, 2,2-dimethoxy-2-phenylacetophenone (abbreviation: DMPAP) (manufactured by Tokyo Chemical Industry Co., Ltd.) was used in the comparative liquid crystal element. In the liquid crystal element 1 and the liquid crystal element 2, DMPAP, which is a polymerization initiator, was not used.

Liquid crystal materials that exhibit a blue phase used in this example: CPP-3FF and PEP-5CNF, chiral agent: ISO- (6OBA) ₂ , non-liquid crystalline monomer: DMeAc, liquid crystalline monomer: Dac-PrEPrEP-O6 and RM257 -O6, polymerization initiator: Structural formula of DMPAP is shown below.

In the liquid crystal element 1, the liquid crystal element 2, and the comparative liquid crystal element, a glass substrate in which a pixel electrode layer and a common electrode layer are formed in a comb shape as shown in FIG. After bonding with a sealing material having a gap (4 μm), each liquid crystal composition shown in Table 1 was injected between substrates in an isotropic phase state by an injection method.

The pixel electrode layer and the common electrode layer were formed by sputtering using indium tin oxide containing silicon oxide. The film thickness was 110 nm, the widths of the pixel electrode layer and the common electrode layer, and the distance between the pixel electrode layer and the common electrode layer were 5 μm. Further, as the sealing material, an ultraviolet ray and a thermosetting sealing material were used, and as a curing treatment, an ultraviolet ray (irradiance: 100 mW / cm ² ) irradiation treatment was performed for 90 seconds, and then a heat treatment was performed at 120 ° C. for 1 hour.

Further, in each of the liquid crystal element 1, the liquid crystal element 2, and the comparative liquid crystal element, the temperature is constant at a temperature at which a blue phase is developed (30 ° C. for the liquid crystal element 1 and liquid crystal element 2 and 41 ° C. for the comparative liquid crystal element), and ultraviolet light (light source metal halide lamp) The polymer was stabilized by irradiation with a wavelength of 365 nm and an irradiance of 9 mW / cm ² . In addition, an optical filter (LU0350, manufactured by Asahi Spectroscopic Co., Ltd.) that cuts a wavelength of 350 nm or less was provided between the light source and the liquid crystal element, and ultraviolet rays from the light source irradiated to the liquid crystal element were adjusted. By the polymer stabilization treatment, monomers contained in the liquid crystal element 1, the liquid crystal element 2, and the comparative liquid crystal element are polymerized, and the liquid crystal element 1, the liquid crystal element 2, and the comparative liquid crystal element are liquid crystal elements having a polymer / liquid crystal composite. It becomes.

A voltage was applied to the liquid crystal element 1, the liquid crystal element 2, and the comparative liquid crystal element, and the transmittance was evaluated for the applied voltage. The characteristic evaluation was performed under the condition where the liquid crystal element 1, the liquid crystal element 2, and the comparative liquid crystal element were sandwiched between crossed Nicol polarizers under the measurement condition that the light source was a halogen lamp and the temperature was room temperature.

FIG. 8 shows the relationship between the applied voltage and the transmittance of the liquid crystal element 1, the liquid crystal element 2, and the comparative liquid crystal element. In FIG. 8, the liquid crystal element 1 is indicated by black rhombus dots, the liquid crystal element 2 is indicated by white circle dots, and the comparative liquid crystal element is indicated by cross marks.

As shown in FIG. 8, like the comparative liquid crystal element using the polymerization initiator, the liquid crystal element 1 and the liquid crystal element 2 that did not use the polymerization initiator also showed good element characteristics.

From the above Example 1 and Example 2, it is understood that Dac-PrEPrEP-O6 used as the liquid crystal monomer in the liquid crystal element 1 and the liquid crystal element 2 is a liquid crystal monomer that can also function as a polymerization initiator. It was.

This is considered to be because the wavelength of the light absorption edge of Dac-PrEPrEP-O6 is longer than 365 nm, and the light irradiated during the polymer stabilization treatment can be absorbed. Polymerization is possible because part of Dac-PrEPrEP-O6 absorbs ultraviolet rays and generates radicals, thereby functioning also as a polymerization initiator.

108 Semiconductor layer 200 Substrate 201 Substrate 202a Alignment film 202b Alignment film 208 Liquid crystal composition 230 Pixel electrode layer 232 Common electrode layer 401 Gate electrode layer 402 Gate insulating layer 403 Semiconductor layer 405a Wiring layer 405b Wiring layer 407 Insulating film 408 Common wiring layer 409 Insulating film 413 Interlayer film 420 Transistor 441 Substrate 442 Substrate 443a Polarizing plate 443b Polarizing plate 444 Liquid crystal composition 446 Electrode layer 446a Electrode layer 446b Electrode layer 446c Electrode layer 446d Electrode layer 447 Electrode layer 447a Electrode layer 447b Electrode layer 447c Electrode layer 447d Electrode Layer 4001 Substrate 4002 Pixel portion 4003 Signal line driver circuit 4003a Signal line driver circuit 4003b Signal line driver circuit 4004 Scan line driver circuit 4005 Sealant 4006 Substrate 4008 Liquid crystal composition 4010 Transition Star 4011 transistor 4013 liquid crystal element 4015 connection terminal electrode 4016 terminal electrode 4018 FPC
4019 Anisotropic conductive film 4020 Insulating layer 4021 Interlayer film 4030 Pixel electrode layer 4031 Common electrode layer 4032a Polarizing plate 4032b Polarizing plate 4034 Light blocking layer 7100 Television apparatus 7101 Housing 7102 Display portion 7103 Stand 7111 Remote control device 7200 Computer 7201 Main body 7202 Case 7203 Display portion 7204 Keyboard 7205 External connection port 7206 Pointing device 7300 Portable game machine 7301a Case 7301b Case 7302 Connection portion 7303a Display portion 7303b Display portion 7304 Speaker portion 7305 Recording medium insertion portion 7306 Operation key 7307 Connection terminal 7308 Sensor 7400 Cellular phone 7401 Housing 7402 Display unit 7403 Operation button 7404 External connection port 7405 Speaker 7406 My 7500 tablet terminal 7501a housing 7501b housing 7502a display unit 7502b display unit 7503 shank 7504 power 7505 operation keys 7506 speaker

Claims (8)

A liquid crystal composition comprising a liquid crystal material exhibiting a blue phase and a liquid crystalline monomer represented by the following general formula (G1).

(In the general formula (G1), R ¹ and R ² each independently represent either hydrogen or a methyl group. In the general formula (G1), X ¹ and X ² are each independently hydrogen or It represents any one of methyl groups, and in the general formula (G1), n and m are each independently an integer of 2 to 20.) A liquid crystal composition comprising a liquid crystal material exhibiting a blue phase and a liquid crystalline monomer represented by the following general formula (G2).

(In the general formula (G 2 ), R ¹ and R ² each independently represents either hydrogen or a methyl group. In the general formula (G 2 ), n and m are each independently 2 to 2) (It is an integer of 20.) A liquid crystal composition comprising a liquid crystal material exhibiting a blue phase and a liquid crystalline monomer represented by the following general formula (G 3 ).

(However, in the general formula (G 3 ), R ¹ and R ² each independently represents either hydrogen or a methyl group.) In any one of Claim 1 thru | or 3,
The liquid crystal monomer represented by the general formula (G1), the general formula (G2), or the general formula (G3) is a liquid crystal composition represented by the following structural formula (100).
In any one of Claims 1 thru | or 4,
The liquid crystalline monomer represented by the general formula (G1), the general formula (G2), the general formula (G3), or the structural formula (100) has a light absorption edge wavelength longer than 320 nm. object. In any one of Claims 1 thru | or 5,
The liquid crystalline monomer represented by the general formula (G1), the general formula (G2), the general formula (G3), or the structural formula (100) has a light absorption edge wavelength longer than 365 nm. object. In any one of Claims 1 thru | or 6,
A liquid crystal composition containing a non-liquid crystalline monomer. In any one of Claims 1 thru | or 7,
A liquid crystal composition containing a chiral agent.