JP2015044794A - Organic compound, liquid crystal composition, liquid crystal element, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel organic compound that can be used in a variety of liquid crystal devices or a liquid crystal composition containing the novel organic compound.SOLUTION: An organic compound represented by General Formula (G1) is provided. A novel liquid crystal composition containing the organic compound is provided. In General Formula (G1), Arrepresents any of a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 4 to 12 carbon atoms, or a substituted or unsubstituted cycloalkenyl group having 4 to 12 carbon atoms. In addition, m represents an integer of 1 or more and 3 or less. Rrepresents a substituted or unsubstituted alkylene group having 1 to 11 carbon atoms.

Description

The present invention relates to an object, a method, or a manufacturing method. Or this invention relates to a process, a machine, a manufacture, or a composition (composition of matter). One embodiment of the present invention relates to a semiconductor device, a display device, a driving method thereof, or a manufacturing method thereof. In particular, one embodiment of the present invention relates to a novel organic compound, a liquid crystal composition including the novel organic compound, a liquid crystal element, a liquid crystal display device, and methods for manufacturing these.

In recent years, liquid crystals have been applied to various devices, and particularly liquid crystal display devices (liquid crystal displays) having thin and light features are used in displays in a wide range of fields.

In order to improve the resolution of moving images and enable a liquid crystal display device with less so-called motion blur, an increase in response speed of liquid crystal is required and development is underway (see, for example, Patent Document 1).

As a liquid crystal display mode capable of high-speed response, a display mode using a liquid crystal exhibiting a blue phase is given. In the mode using a liquid crystal that develops a blue phase, a high-speed response is achieved, an alignment film is unnecessary, and a wide viewing angle can be obtained. , See Patent Document 2).

JP 2008-303381 A International Publication No. 2005-090520

Thus, an object of one embodiment of the present invention is to provide a novel organic compound that can be used for a variety of liquid crystal devices.

Another object is to provide a liquid crystal composition including the novel organic compound. Another object is to provide a liquid crystal composition including the novel organic compound and capable of developing a blue phase.

Another object is to provide a liquid crystal element using a liquid crystal composition including the novel organic compound.

Another object is to provide a liquid crystal display device using a liquid crystal composition including the novel organic compound. Another object is to provide a liquid crystal display device with high contrast by using a liquid crystal composition including the novel organic compound.

Note that the description of these problems does not disturb the existence of other problems. In one embodiment of the present invention, it is not necessary to solve all of these problems. Problems other than those described above are naturally clarified from the description of the specification and the like, and problems other than the above can be extracted from the description of the specification and the like.

One embodiment of the present invention is an organic compound represented by General Formula (G1) below.

In General Formula (G1), Ar ¹ represents a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, or a substituted or unsubstituted carbon group having 3 to 12 carbon atoms. Represents any of the 12 cycloalkenyl groups. M is an integer of 1 to 3. R ¹ represents a substituted or unsubstituted alkylene group having 1 to 11 carbon atoms.

Another embodiment of the present invention is a liquid crystal composition including the organic compound represented by the general formula (G1).

Another embodiment of the present invention is a liquid crystal composition that includes the organic compound represented by the above general formula (G1) and a chiral agent and exhibits a blue phase. Note that the blue phase is expressed in a liquid crystal composition having a strong twisting power and has a double twisted structure. A liquid crystal composition capable of developing a blue phase exhibits a cholesteric phase, a cholesteric blue phase, an isotropic phase, or the like depending on conditions.

Another embodiment of the present invention is a liquid crystal composition that expresses a blue phase as the liquid crystal composition and has a diffraction wavelength peak on the longest wavelength side in a reflection spectrum of 500 nm or less.

The diffraction wavelength means that the reflection spectrum of the liquid crystal composition is measured at a temperature at which the blue phase is developed, and the shorter the diffraction wavelength, the smaller the blue phase crystal lattice and the stronger the twisting power. . When the twisting force of the liquid crystal composition is strong, the transmittance of the liquid crystal composition can be kept low when no voltage is applied (when the applied voltage is 0 V), so that the liquid crystal display device using the liquid crystal composition has high contrast. Is possible.

In addition, as an index of the strength of the twisting force of the liquid crystal composition, there are a helical pitch, a selective reflection wavelength, HTP (Helical Twisting Power), and a diffraction wavelength. Of these, the helical pitch, the selective reflection wavelength, and HTP are cholesteric phases. It becomes evaluation in. On the other hand, since the diffraction wavelength can be evaluated only in the blue phase, it is effective for evaluating the twisting force of the blue phase.

Another embodiment of the present invention is a liquid crystal element using the above liquid crystal composition.

Another embodiment of the present invention is a liquid crystal display device using the above liquid crystal composition. The liquid crystal display device may contain an organic resin.

According to one embodiment of the present invention, a novel organic compound applicable to a liquid crystal device can be provided.

Alternatively, according to one embodiment of the present invention, a liquid crystal composition including a novel organic compound can be provided. Alternatively, according to one embodiment of the present invention, a liquid crystal composition including a novel organic compound and capable of developing a blue phase can be provided.

Alternatively, a liquid crystal element using a liquid crystal composition including the novel organic compound can be provided.

Alternatively, a liquid crystal display device using a liquid crystal composition including the novel organic compound can be provided. Alternatively, a liquid crystal display device with high contrast can be provided by using a liquid crystal composition including the novel organic compound.

4A and 4B illustrate one embodiment of a liquid crystal element and a liquid crystal display device. 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 BM-3-EPPFFF. ¹ H NMR chart of BM-5-EPPFFF. 6A and 6B illustrate a relationship between a wavelength of a liquid crystal element manufactured in an example and reflected light intensity.

Hereinafter, embodiments and examples of the disclosed invention will be described in detail with reference to the drawings. However, the invention disclosed in this specification is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed. Further, the invention disclosed in this specification is not construed as being limited to the description of the embodiments below. Note that in the structures described below, the same portions or 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 in which an FPC (Flexible printed circuit) or TCP (Tape Carrier Package) is attached, a module in which a printed wiring board is provided at the end of TCP, or a display element is formed by a COG (Chip On Glass) method. All modules on which (integrated circuit) is directly mounted are also included in the liquid crystal display device. 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.

In the following, the ordinal numbers given as “first”, “second”, etc. are used for convenience and do not indicate the order of steps or the order of lamination. Therefore, for example, the description can be made by appropriately replacing “first” with “second” or “third”. In addition, the ordinal numbers described in this specification and the like may not match the ordinal numbers used to specify one embodiment of the present invention.

In the present specification, the peak of the diffraction wavelength in the reflection spectrum refers to the maximum value of the peak on the longest wavelength side (value at the peak apex). Therefore, when there are a plurality of peaks in the reflection spectrum, the maximum value of the peak appearing on the longest wavelength side is the peak of the diffraction wavelength, and even a peak having a shoulder (having a step or a small peak) The maximum value of the peak is taken as the peak of the diffraction wavelength.

(Embodiment 1)
In this embodiment, a novel organic compound according to one embodiment of the present invention will be described.

The novel organic compound according to one embodiment of the present invention is an organic compound represented by General Formula (G1) below.

In General Formula (G1), Ar ¹ represents a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 4 to 12 carbon atoms, or a substituted or unsubstituted carbon atom having 3 to 3 carbon atoms. Represents any of the 12 cycloalkenyl groups. M is an integer of 1 to 3. R ¹ represents a substituted or unsubstituted alkylene group having 1 to 11 carbon atoms.

In the general formula (G1), examples of the substituent that can be bonded to Ar ¹ or R ¹ include fluorine (F), bromine (Br), chlorine (Cl), iodine (I), cyano group (CN), Fluoromethyl group (CF ₃ ), trifluoromethylsulfonyl group (SO ₂ CF ₃ ), nitro group (NO ₂ ), isothiocyanate group (NCS), thiocyanate group (SCN), pentafluorosulfanyl group (SF ₅ ), etc. And an electron-withdrawing substituent.

Specific examples of the organic compound represented by General Formula (G1) include structures represented by Structural Formula (100) to Structural Formula (109). However, the present invention is not limited to these.

As a method for synthesizing the organic compound represented by the general formula (G1) in this embodiment, various reactions can be applied.

For example, the organic compound according to General Formula (G1) can be synthesized by the following synthesis scheme (A-1).

As shown in the synthesis scheme (A-1), an esterification reaction between an alkanedicarboxylic acid (compound 1) and a hydroxyaryl derivative (compound 2) is performed, and the compound is represented by the general formula (G1) of one embodiment of the present invention. Organic compounds can be synthesized.

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 concentrated sulfuric acid or para-toluenesulfonic acid, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide / hydrochloride (abbreviation: EDC), dicyclohexylcarbodiimide (abbreviation: DCC) can be used.

In Synthesis Scheme (A-1), Ar ¹ represents a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, or a substituted or unsubstituted carbon number. It represents any of 3 to 12 cycloalkenyl groups. M is an integer of 1 to 3. R ¹ represents a substituted or unsubstituted alkylene group having 1 to 11 carbon atoms.

The organic compound represented by the general formula (G1) in this embodiment obtained as described above can be used as a material for a liquid crystal composition.

The liquid crystal composition of one embodiment of the present invention includes a chiral agent in addition to the organic compound represented by the general formula (G1). Further, in addition to the organic compound represented by the general formula (G1), other liquid crystalline compounds and / or non-liquid crystalline compounds may be contained.

In addition, the liquid crystal composition of one embodiment of the present invention contains a chiral agent in addition to the organic compound represented by the general formula (G1), and exhibits a blue phase.

The chiral agent is used to induce twist of the liquid crystal composition, to align the liquid crystal composition in a spiral structure and to develop a blue phase. The chiral agent is a compound having an asymmetric center, and a compound having a good compatibility with the liquid crystal composition and a strong twisting power is used. Further, the chiral agent is an optically active substance, and the higher the optical purity, the more preferable it is 99% or more.

The liquid crystal composition containing the organic compound represented by the general formula (G1) can have a diffraction wavelength peak on the longest wavelength side in the reflection spectrum as short as 500 nm or less, and has a strong twisting power. Therefore, the amount of the chiral agent to be added can be reduced.

As described above, this embodiment can be implemented in appropriate combination with the structures described in the other embodiments.

(Embodiment 2)
In this embodiment, a liquid crystal element and a liquid crystal display device to which the organic compound represented by the general formula (G1) described in Embodiment 1 or a liquid crystal composition containing the organic compound is applied are described with reference to drawings. I will explain.

The liquid crystal composition according to one embodiment of the present invention includes the organic compound represented by the general formula (G1) described in Embodiment 1 and a chiral agent, and develops a blue phase.

The liquid crystal composition is a liquid crystal composition having a strong twisting power with a diffraction wavelength peak on the longest wavelength side in the reflection spectrum being 500 nm or less. When the twisting force of the liquid crystal composition is strong, the transmittance of the liquid crystal composition when no voltage is applied (when the applied voltage is 0 V) can be kept low, so that the liquid crystal display device using the liquid crystal composition has high contrast. Is possible.

In the liquid crystal composition according to this embodiment, the peak of the diffraction wavelength on the longest wavelength side in the reflection spectrum is as short as 500 nm or less, and the twisting power is strong, so that the amount of the chiral agent to be added can be reduced. . For example, the ratio of the chiral agent contained in the liquid crystal composition may be 10 wt% or less. When a large amount of chiral agent is added to improve the twisting power of the liquid crystal composition, the driving voltage for driving the liquid crystal composition is increased. If the amount of the chiral agent to be added can be reduced, the driving voltage can be kept low, so that power consumption can be reduced.

Examples of a liquid crystal element and a liquid crystal display device according to one embodiment of the present invention are illustrated in FIGS.

FIG. 1 shows a liquid crystal display device in which a first substrate 200 and a second substrate 201 are arranged so as to face each other with a liquid crystal composition 208 using a liquid crystal composition expressing a blue phase interposed therebetween. is there. A pixel electrode layer 230 and a common electrode layer 232 are provided adjacent to each other between the first substrate 200 and the liquid crystal composition 208.

In a liquid crystal display device using a liquid crystal composition that develops a blue phase, an electric field that is roughly parallel to the substrate (that is, a horizontal direction) is generated, and liquid crystal molecules are moved in a plane parallel to the substrate to control gradation. Can be used.

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. Composed. In this embodiment, the liquid crystal element includes an organic compound and a chiral agent represented by the general formula (G1) between at least a pair of electrode layers (the pixel electrode layer 230 and the common electrode layer 232 having different potentials), A liquid crystal composition 208 capable of exhibiting a blue phase is included. Since the blue phase is optically isotropic, it does not depend on the viewing angle, and it is not necessary to form an alignment film, so that the quality of the display image can be improved and the cost can be reduced.

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 forming the liquid crystal composition 208, a dispenser method (a dropping method) or an injection method in which liquid crystal is injected using a capillary phenomenon after the first substrate 200 and the second substrate 201 are bonded to each other is used. Can do.

In the liquid crystal display device, it is preferable to add a polymerizable monomer to the liquid crystal composition and perform polymer stabilization treatment in order to widen the temperature range in which the blue phase appears. As the polymerizable monomer, not only a vinyl monomer but also, for example, a thermopolymerizable (thermosetting) oligomer that undergoes polymerization by heat, a photopolymerizable (photocurable) oligomer that undergoes polymerization by light, or the like is used. it can.

The polymerizable vinyl monomer may be a monofunctional monomer such as acrylate or methacrylate, may be a polyfunctional monomer such as diacrylate, triacrylate, dimethacrylate, or trimethacrylate, or may be a mixture of these. Further, it may be liquid crystalline or non-liquid crystalline, and both may be mixed.

When the polymer is stabilized, a polymerization initiator may be added to the liquid crystal composition. The polymerization initiator may be a radical polymerization initiator that generates radicals by light irradiation or heating, an acid generator that generates acid, or a base generator that generates a base.

For example, a polymeric monomer and a photopolymerization initiator can be added to the liquid crystal composition, and polymer stabilization treatment can be performed by irradiating light.

The polymer stabilization treatment may be performed in a state showing an isotropic phase, or may be performed in a state where a temperature is controlled and a blue phase is developed. The temperature at which the blue phase is changed to the isotropic phase when the temperature is raised or the temperature at which the isotropic phase is changed to the blue phase when the temperature is lowered is called a phase transition temperature between the blue phase and the isotropic phase. As an example of polymer stabilization treatment, after heating the liquid crystal composition to which the photopolymerizable monomer has been added to the isotropic phase, the temperature is gradually lowered to the blue phase to maintain the temperature at which the blue phase appears. In this state, light irradiation can be performed.

The liquid crystal composition 208 after the polymer stabilization treatment contains a polymer. In other words, the liquid crystal composition according to one embodiment of the present invention may include an organic resin.

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.

The liquid crystal composition described in this embodiment is a liquid crystal composition having a diffraction wavelength peak on the longest wavelength side in a reflection spectrum of 500 nm or less and a strong twisting power. If the twisting force of the liquid crystal composition is strong, the transmittance of the liquid crystal composition when no voltage is applied (when the applied voltage is 0 V) can be kept low. Therefore, a liquid crystal display device using the liquid crystal composition has high contrast and can do. With high contrast, a high-quality liquid crystal display device with high visibility can be provided.

In addition, since the liquid crystal composition exhibiting a blue phase can respond at high speed, the performance of the liquid crystal display device can be improved.

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.

Although not shown in FIG. 1, an optical film such as a polarizing plate, a retardation plate, and an antireflection film is 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).

A transmissive liquid crystal display device that performs display by transmitting light from a light source using a liquid crystal composition that expresses a blue phase disclosed in this specification for a liquid crystal display device, and displays by reflecting incident light. A reflective liquid crystal display device or a transflective liquid crystal display device having both a transmissive type and a reflective type can be provided.

In the case of a transmissive liquid crystal display device, the first substrate, the second substrate, other insulating films, conductive films, and the like that exist in a pixel region through which light is transmitted are transparent to light in the visible wavelength region. And The pixel electrode layer and the common electrode layer are preferably translucent. However, in the case of having an opening pattern, a non-translucent material such as a metal film may be used depending on the shape.

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. That's fine. In this specification, translucency refers to a property of transmitting at least light in the visible wavelength region.

The pixel electrode layer 230 and the common electrode layer 232 include indium tin oxide, a conductive material in which zinc oxide (ZnO) is mixed in indium oxide, a conductive material in which silicon oxide (SiO ₂ ) is mixed in indium oxide, and indium containing tungsten oxide. 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), aluminum (Al), copper (Cu ), A metal such as silver (Ag), an alloy thereof, or a metal nitride thereof, or It can be formed using several.

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.

A liquid crystal display device that achieves high contrast can be provided using the liquid crystal composition exhibiting a blue phase of one embodiment of the present invention.

This embodiment can be implemented in appropriate combination with the structures 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 transverse electric field mode shown in the IPS mode or the like includes, for example, a first electrode layer having an opening pattern below the liquid crystal composition (for example, a pixel electrode layer in which a voltage is controlled for each pixel) and a second electrode layer (for example, A common electrode layer to which a common voltage is supplied to all pixels. 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 insulating film. The first electrode layer 447 and the second electrode layer 446 have various shapes and include, for example, an opening, a bent portion, a branched portion, or a comb-like portion. Since an electric field substantially parallel to the substrate is generated between the first electrode layer 447 and the second electrode layer 446, an arrangement with the same shape and completely overlapping is avoided.

Alternatively, a structure used in the FFS mode may be applied 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 shapes. For example, it includes an opening, a bent portion, a branched portion, or a comb-like portion. Since the first electrode layer 447 and the second electrode layer 446 generate an electric field in an oblique direction with respect to the substrate between the electrodes, an arrangement with the same shape and completely overlapping is avoided.

As the liquid crystal composition 444, a liquid crystal composition containing the organic compound represented by the general formula (G1) described in Embodiment 1 is used. Preferably, a liquid crystal composition including the general formula (G1) described in Embodiment 1 and a chiral agent and exhibiting a blue phase is used. More preferably, a liquid crystal composition including the general formula (G1) shown in Embodiment Mode 1 and a chiral agent, having a diffraction wavelength peak on the longest wavelength side in the reflection spectrum of 500 nm or less and expressing a blue phase is used. . In addition, the liquid crystal composition 444 may include an organic resin. In this embodiment, the liquid crystal composition 444 can be formed by performing polymer stabilization treatment in a state where a blue phase is developed.

By forming an electric field in the horizontal direction between the first electrode layer 447 and the second electrode layer 446, the liquid crystal of the liquid crystal composition 444 is controlled.

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 corrugated openings, and in FIG. 3B, the first electrode layer 447b and the second electrode layer 446b are 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 The layer 447d and the second electrode layer 446d are comb-shaped and have shapes 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 since the second electrode layer 446 has a shape having an opening pattern, the second electrode layer 446 is 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. A wiring layer 405a and a wiring layer 405b that function are included.

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 formation method of the interlayer film 413 is not particularly limited, and depending on the material, spin coating, dipping, spray coating, droplet discharge method (inkjet method), screen printing, offset printing, roll coating, curtain coating, knife, etc. A coat or the like can be used.

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 dispenser 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. Moreover, a filler and a coupling agent may be included.

In the case where the liquid crystal composition exhibits a blue phase, the liquid crystal composition is filled in the gap between the first substrate 441 and the second substrate 442 and then irradiated with light to perform polymer stabilization treatment. Preferably, 444 is formed. The light is light having a wavelength at which the polymerizable monomer contained in the liquid crystal composition used as the liquid crystal composition 444 and the photopolymerization initiator react. By this polymer stabilization treatment by light irradiation, the temperature range in which the liquid crystal composition 444 develops a blue phase can be widely improved.

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, you may use the circularly-polarizing plate by a polarizing plate and a phase difference plate. Through the above steps, a liquid crystal display device can be completed.

In the case where a plurality of liquid crystal display devices are manufactured using a large substrate (so-called multi-cavity), the dividing step can be performed before the polymer stabilization treatment or before the polarizing plate is provided. Considering the influence on the liquid crystal composition by the dividing step (alignment disorder due to force applied during the dividing step), it is preferable that the first substrate and the second substrate are bonded together and before the polymer stabilization treatment. .

Although not shown, a backlight, a sidelight, or the like may be used as the light source. The light source is installed 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 indium tin oxide, 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 containing a conductive polymer. The pixel electrode formed using the conductive composition preferably has a sheet resistance of 10,000 Ω / □ or less and a light transmittance of 70% or more at a wavelength of 550 nm. Moreover, it is preferable that the resistivity of the conductive polymer contained in the conductive composition is 0.1 Ω · cm or less.

As the conductive polymer, a so-called π-conjugated conductive polymer can be used. For example, polyaniline or a derivative thereof, polypyrrole or a derivative thereof, polythiophene or a derivative thereof, a copolymer of two or more of aniline, pyrrole, and thiophene or a derivative thereof can be given.

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 gate electrode layer 401 is formed as a single layer or a stacked layer 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. Can do. 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. When a light-shielding conductive film 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.

For example, the two-layer structure of the gate electrode layer 401 includes a two-layer structure in which a molybdenum layer is stacked over an aluminum layer, a two-layer structure in which a molybdenum layer is stacked over a copper layer, or a copper layer. A two-layer structure in which a titanium nitride layer or a tantalum nitride layer is stacked, or a two-layer structure in which a titanium nitride layer and a molybdenum layer are stacked is preferable. The three-layer structure is preferably a stacked structure in which a tungsten layer or a tungsten nitride layer, an aluminum / silicon alloy layer or an aluminum / titanium alloy layer, and a titanium nitride layer or a titanium layer are stacked.

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, as the material of the gate insulating layer 402, 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.

The silicon oxide film can also be formed by a CVD method using an organosilane gas. Examples of the organic silane gas include tetraethoxysilane (TEOS: chemical formula Si (OC ₂ H ₅ ) ₄ ), tetramethylsilane (TMS: chemical formula Si (CH ₃ ) ₄ ), tetramethylcyclotetrasiloxane (TMCTS), octamethylcyclotetra Use of silicon-containing compounds such as siloxane (OMCTS), hexamethyldisilazane (HMDS), triethoxysilane (SiH (OC ₂ H ₅ ) ₃ ), trisdimethylaminosilane (SiH (N (CH ₃ ) ₂ ) ₃ ) Can do. 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, an amorphous material (also referred to as an amorphous material) manufactured by a physical vapor deposition method such as a chemical vapor deposition method or a sputtering method using a semiconductor material gas typified by silane or germane is used. ) A semiconductor, a polycrystalline semiconductor obtained by crystallizing the amorphous semiconductor using light energy or thermal energy, or a microcrystalline semiconductor in which a fine crystalline phase and an amorphous phase are mixed can be used.

A typical example of an amorphous semiconductor is hydrogenated amorphous silicon, and a typical example of a crystalline semiconductor is polysilicon. Polysilicon (polycrystalline silicon) is mainly made of so-called high-temperature polysilicon using polysilicon formed through a process temperature of 800 ° C. or higher as a main material, or polysilicon formed at a process temperature of 600 ° C. or lower. And so-called low-temperature polysilicon, and polysilicon obtained by crystallizing amorphous silicon using an element that promotes crystallization. Needless to say, as described above, a microcrystalline semiconductor or a semiconductor including a crystalline phase in part of a semiconductor layer can be used.

An oxide semiconductor film may be used as the semiconductor layer 403, and the oxide semiconductor film preferably contains at least indium (In), particularly In and zinc (Zn). In addition, it is preferable that gallium (Ga) be included in addition to the stabilizer for reducing variation in electrical characteristics of the transistor including the oxide semiconductor film. Moreover, it is preferable to have tin (Sn) as a stabilizer. Moreover, it is preferable to have hafnium (Hf) as a stabilizer. Moreover, it is preferable to have aluminum (Al) as a stabilizer. Moreover, it is preferable to have a zirconium (Zr) as a stabilizer.

As other stabilizers, lanthanoids such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb) , Dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), or lutetium (Lu).

For example, as an oxide semiconductor, indium oxide, tin oxide, zinc oxide, an In—Zn-based oxide, an In—Mg-based oxide, an In—Ga-based oxide, an In—Ga—Zn-based oxide (IGZO) ), In—Al—Zn oxide, In—Sn—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-based oxide, In-Ho-Zn-based oxide, In-Er-Zn-based oxide, In-Tm-Zn-based oxide, In-Yb-Zn-based oxide, In-Lu- Zn-based oxide, In-Sn-Ga-Zn-based oxide, In-Hf-Ga- An n-based oxide, an In-Al-Ga-Zn-based oxide, an In-Sn-Al-Zn-based oxide, an In-Sn-Hf-Zn-based oxide, or an In-Hf-Al-Zn-based oxide is used. be able to.

Note that here, for example, an In—Ga—Zn-based 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.

Alternatively, a material represented by InMO ₃ (ZnO) _m (m> 0 is satisfied, and m is not an integer) may be used as the oxide semiconductor. Note that M represents one metal element or a plurality of metal elements selected from Ga, Fe, Mn, and Co. Alternatively, a material represented by In ₂ SnO ₅ (ZnO) _n (n> 0 is satisfied, and n is an integer) may be used as the oxide semiconductor.

For example, In: Ga: Zn = 1: 1: 1, In: Ga: Zn = 2: 2: 1, or In: Ga: Zn = 3: 1: 2 atomic ratio In—Ga—Zn-based oxidation Or an oxide in the vicinity of the composition can be used. Alternatively, In: Sn: Zn = 1: 1: 1, In: Sn: Zn = 2: 1: 3, or In: Sn: Zn = 2: 1: 5 atomic ratio In—Sn—Zn-based oxide Or an oxide in the vicinity of the composition may be used.

However, the oxide semiconductor is not limited thereto, and an oxide semiconductor having an appropriate composition may be used depending on required semiconductor characteristics (mobility, threshold value, variation, and the like). In order to obtain the required semiconductor characteristics, it is preferable that the carrier concentration, the impurity concentration, the defect density, the atomic ratio between the metal element and oxygen, the interatomic distance, the density, and the like are appropriate.

For example, high mobility can be obtained relatively easily with an In—Sn—Zn-based oxide. However, mobility can be increased by reducing the defect density in the bulk also in the case of using an In—Ga—Zn-based oxide.

Hereinafter, the structure of the oxide semiconductor film is described.

An oxide semiconductor film is classified roughly into a single crystal oxide semiconductor film and a non-single crystal oxide semiconductor film. The non-single-crystal oxide semiconductor film refers to an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, a polycrystalline oxide semiconductor film, a CAAC-OS (C Axis Crystalline Oxide Semiconductor) film, or the like.

An amorphous oxide semiconductor film is an oxide semiconductor film having an irregular atomic arrangement in the film and having no crystal component. An oxide semiconductor film which has no crystal part even in a minute region and has a completely amorphous structure as a whole is typical.

The microcrystalline oxide semiconductor film includes a microcrystal (also referred to as nanocrystal) with a size greater than or equal to 1 nm and less than 10 nm, for example. Therefore, the microcrystalline oxide semiconductor film has higher regularity of atomic arrangement than the amorphous oxide semiconductor film. Therefore, a microcrystalline oxide semiconductor film has a feature that the density of defect states is lower than that of an amorphous oxide semiconductor film.

The CAAC-OS film is one of oxide semiconductor films having a plurality of crystal parts, and most of the crystal parts are large enough to fit in a cube whose one side is less than 100 nm. Therefore, the case where a crystal part included in the CAAC-OS film fits in a cube whose one side is less than 10 nm, less than 5 nm, or less than 3 nm is included. The CAAC-OS film is characterized by having a lower density of defect states than a microcrystalline oxide semiconductor film. Hereinafter, the CAAC-OS film is described in detail.

When the CAAC-OS film is observed with a transmission electron microscope (TEM), a clear boundary between crystal parts, that is, a grain boundary (also referred to as a grain boundary) cannot be confirmed. Therefore, it can be said that the CAAC-OS film is unlikely to decrease in electron mobility due to crystal grain boundaries.

When the CAAC-OS film is observed by TEM (cross-sectional TEM observation) from a direction substantially parallel to the sample surface, it can be confirmed that metal atoms are arranged in layers in the crystal part. Each layer of metal atoms has a shape reflecting unevenness of a surface (also referred to as a formation surface) or an upper surface on which the CAAC-OS film is formed, and is arranged in parallel with the formation surface or the upper surface of the CAAC-OS film. .

On the other hand, when the CAAC-OS film is observed by TEM (planar TEM observation) from a direction substantially perpendicular to the sample surface, it can be confirmed that metal atoms are arranged in a triangular shape or a hexagonal shape in the crystal part. However, there is no regularity in the arrangement of metal atoms between different crystal parts.

From the cross-sectional TEM observation and the planar TEM observation, it is found that the crystal part of the CAAC-OS film has orientation.

When structural analysis is performed on a CAAC-OS film using an X-ray diffraction (XRD) apparatus, for example, in the analysis of a CAAC-OS film having an InGaZnO ₄ crystal by an out-of-plane method, A peak may appear when the diffraction angle (2θ) is around 31 °. Since this peak is attributed to the (009) plane of the InGaZnO ₄ crystal, the CAAC-OS film crystal has c-axis orientation, and the c-axis is in a direction substantially perpendicular to the formation surface or the top surface. Can be confirmed.

On the other hand, when the CAAC-OS film is analyzed by an in-plane method in which X-rays are incident from a direction substantially perpendicular to the c-axis, a peak may appear when 2θ is around 56 °. This peak is attributed to the (110) plane of the InGaZnO ₄ crystal. In the case of a single crystal oxide semiconductor film of InGaZnO ₄ , when 2θ is fixed in the vicinity of 56 ° and analysis (φ scan) is performed while rotating the sample with the normal vector of the sample surface as the axis (φ axis), Six peaks attributed to the crystal plane equivalent to the (110) plane are observed. On the other hand, in the case of a CAAC-OS film, a peak is not clearly observed even when φ scan is performed with 2θ fixed at around 56 °.

From the above, in the CAAC-OS film, the orientation of the a-axis and the b-axis is irregular between different crystal parts, but the c-axis is aligned, and the c-axis is a normal line of the formation surface or the top surface. It can be seen that the direction is parallel to the vector. Therefore, each layer of metal atoms arranged in a layer shape confirmed by the above-mentioned cross-sectional TEM observation is a plane parallel to the ab plane of the crystal.

Note that the crystal part is formed when a CAAC-OS film is formed or when crystallization treatment such as heat treatment is performed. As described above, the c-axis of the crystal is oriented in a direction parallel to the normal vector of the formation surface or the top surface of the CAAC-OS film. Therefore, for example, when the shape of the CAAC-OS film is changed by etching or the like, the c-axis of the crystal may not be parallel to the normal vector of the formation surface or the top surface of the CAAC-OS film.

Further, the crystallinity in the CAAC-OS film is not necessarily uniform. For example, in the case where the crystal part of the CAAC-OS film is formed by crystal growth from the vicinity of the top surface of the CAAC-OS film, the region near the top surface can have a higher degree of crystallinity than the region near the formation surface. is there. In addition, in the case where an impurity is added to the CAAC-OS film, the crystallinity of a region to which the impurity is added changes, and a region having a different degree of crystallinity may be formed.

Note that when the CAAC-OS film including an InGaZnO ₄ crystal is analyzed by an out-of-plane method, a peak may also appear when 2θ is around 36 ° in addition to the peak where 2θ is around 31 °. A peak at 2θ of around 36 ° indicates that a crystal having no c-axis alignment is included in part of the CAAC-OS film. The CAAC-OS film preferably has a peak at 2θ of around 31 ° and no peak at 2θ of around 36 °.

In a transistor using a CAAC-OS film, change in electrical characteristics due to irradiation with visible light or ultraviolet light is small. Therefore, the transistor has high reliability.

Note that the oxide semiconductor film may be a stacked film including two or more of an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, and a CAAC-OS film, for example.

In this specification, “parallel” refers to a state in which two straight lines are arranged at an angle of −10 ° to 10 °. Therefore, the case of −5 ° to 5 ° is also included. “Vertical” refers to a state in which two straight lines are arranged at an angle of 80 ° to 100 °. Therefore, the case of 85 ° to 95 ° is also included.

In this specification, when a crystal is trigonal or rhombohedral, it is represented as a hexagonal system.

As a material of the wiring layer 405a and the wiring layer 405b functioning as the source electrode layer or the drain electrode layer, an element selected from Al, Cr, Ta, Ti, Mo, W, or an alloy containing the above-described element as a component, Examples thereof include an alloy film in which the above-described elements are combined. 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 element as a component, an alloy film combining the above elements, or a nitride containing the above element as a component.

The gate insulating layer 402, the semiconductor layer 403, the wiring layer 405a functioning as a source or drain electrode layer, and the wiring layer 405b may be formed successively without exposure to the air. By continuously forming the film without being exposed to the atmosphere, each stacked interface can be formed without being contaminated by atmospheric components or impurity elements contained in the atmosphere, so that variation in transistor characteristics can be reduced. .

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

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. Further, a low dielectric constant material (low-k material), a siloxane resin, PSG (phosphorus glass), BPSG (phosphorus boron glass), or the like can be used. Alternatively, a gallium oxide film may be used as the insulating film 407. Alternatively, an organic material such as polyimide, acrylic resin, benzocyclobutene resin, polyamide, or epoxy resin can be used.

Note that the siloxane-based resin corresponds to a resin including a Si—O—Si bond formed using a siloxane-based material as a starting material. Siloxane resins may use organic groups (for example, alkyl groups and aryl groups) and fluorine as substituents. The organic group may have fluorine. A siloxane-based resin can be used as the insulating film 407 by forming a film by a coating method and baking it.

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.

In addition, when a resist mask having a plurality of (typically two types) thickness regions formed using a multi-tone mask is used, the number of resist masks can be reduced, which simplifies processes and reduces costs. I can plan.

As described above, since a liquid crystal composition having an organic compound represented by the general formula (G1) and a chiral agent can exhibit a blue phase, a liquid crystal display device using the liquid crystal composition has a high-speed response and Wide viewing angle is possible. In addition, the liquid crystal composition according to one embodiment of the present invention can be a liquid crystal composition exhibiting a blue phase whose diffraction wavelength peak on the longest wavelength side in a reflection spectrum is 500 nm or less. Since a liquid crystal display device using the liquid crystal composition can have high contrast, a high-quality liquid crystal display device with high visibility can be provided.

This embodiment can be implemented in appropriate combination with the structures described in the other embodiments.

(Embodiment 4)
A liquid crystal display device having a display function can be manufactured using the transistor in the pixel portion and further in the driver circuit. In addition, part or all of the driver circuit can be formed over the same substrate as the pixel portion to form a system-on-panel.

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 a panel in which the transistors 4010 and 4011 and the liquid crystal element 4013 formed over the first substrate 4001 are sealed with a sealant 4005 between the second substrate 4006 and FIGS. 4B is a top view, 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 The transistor 4011 included in the driver circuit 4004 is illustrated. An insulating layer 4020 and an interlayer film 4021 are provided over 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.

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, a liquid crystal composition including the organic compound represented by General Formula (G1) described in Embodiment 1 is used. The liquid crystal composition provided as the liquid crystal composition 4008 may include an organic resin.

For the pixel electrode layer 4030 and the common electrode layer 4031, the structure of the pixel electrode layer and the common electrode layer as described in Embodiment Mode 2 can be applied.

In this embodiment, the liquid crystal composition 4008 includes the organic compound represented by the general formula (G1) and the chiral agent described in Embodiment 1, and uses a liquid crystal composition that exhibits a blue phase to stabilize the polymer. By the treatment, the liquid crystal display device is provided in a state where a blue phase is developed (a state exhibiting a blue phase or a state exhibiting a blue phase). Therefore, in this embodiment mode, the pixel electrode layer 4030 and the common electrode layer 4031 as illustrated in FIG. 1 of Embodiment Mode 2 and FIG. 3 of Embodiment Mode 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.

The liquid crystal composition 4008 preferably has a diffraction wavelength peak on the longest wavelength side in the reflection spectrum of 500 nm or less. Such a liquid crystal composition is a liquid crystal composition having a strong twisting force. When the twisting force of the liquid crystal composition is strong, the transmittance of the liquid crystal composition when no voltage is applied (when the applied voltage is 0 V) can be kept low. Therefore, a liquid crystal display using the liquid crystal composition as the liquid crystal composition 4008 It is possible to increase the contrast of the apparatus.

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, a PVF (polyvinyl fluoride) film, a polyester film, or an acrylic resin film can be used. Alternatively, a sheet having a structure in which an aluminum foil is sandwiched between PVF films or polyester films, or an FRP (Fiberglass-Reinforced Plastics) plate can be used.

Reference numeral 4035 denotes a columnar spacer obtained by selectively etching the insulating film, and is provided for controlling 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 to 20 μm. 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, the present invention can be applied to either a transflective liquid crystal display device or a reflective liquid crystal display device.

4 illustrates an example in which a polarizing plate is provided outside the first substrate 4001 and the second substrate 4006, the polarizing plate may be provided inside 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.

A structure covered with an insulating layer 4020 functioning as a protective film of the transistor may be employed, but is not particularly limited.

Note that the protective film is for preventing intrusion of 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 laminated is not particularly limited, and depending on the material, a sputtering method, spin coating, dipping method, spray coating method, droplet discharge method (inkjet method), screen printing, offset printing, rolls, etc. A coat, a curtain coat, a knife coat, etc. can be used.

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, indium tin oxide, A light-transmitting conductive material such as indium zinc 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 formed separately 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, since a liquid crystal composition having an organic compound represented by the general formula (G1) and a chiral agent can exhibit a blue phase, a liquid crystal display device using the liquid crystal composition has a high-speed response and Wide viewing angle is possible. In addition, the liquid crystal composition according to one embodiment of the present invention can be a liquid crystal composition exhibiting a blue phase whose diffraction wavelength peak on the longest wavelength side in a reflection spectrum is 500 nm or less. Since a liquid crystal display device using the liquid crystal composition can have high contrast, a high-quality liquid crystal display device with high visibility can be provided.

This embodiment can be implemented in appropriate combination with the structures described in the other embodiments.

(Embodiment 5)
The liquid crystal display device disclosed in this specification can be applied to a variety of electronic devices (including game machines). Examples of the electronic device include 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 (also referred to as a mobile phone or a mobile phone device). ), Large game machines such as portable game machines, portable information terminals, sound reproducing devices, and pachinko machines.

FIG. 5A illustrates a laptop personal computer, which includes a main body 3001, a housing 3002, a display portion 3003, a keyboard 3004, and the like. By applying the liquid crystal display device described in the above embodiment to the display portion 3003, a laptop personal computer with high contrast, high visibility, and high reliability can be provided.

FIG. 5B illustrates a personal digital assistant (PDA). A main body 3021 is provided with a display portion 3023, an external interface 3025, operation buttons 3024, and the like. There is a stylus 3022 as an accessory for operation. By applying the liquid crystal display device described in the above embodiment to the display portion 3023, a highly portable personal digital assistant (PDA) with high contrast, high visibility, and high reliability can be provided.

FIG. 5C illustrates an electronic book, which includes two housings, a housing 2701 and a housing 2703. The housing 2701 and the housing 2703 are integrated with a shaft portion 2711 and can be opened / closed using the shaft portion 2711 as an axis. With such a configuration, an operation like a paper book can be performed.

A display portion 2705 and a display portion 2707 are incorporated in the housing 2701 and the housing 2703, respectively. The display unit 2705 and the display unit 2707 may be configured to display a continuous screen or may be configured to display different screens. By adopting a configuration in which different screens are displayed, for example, text is displayed on the right display unit (display unit 2705 in FIG. 5C) and an image is displayed on the left display unit (display unit 2707 in FIG. 5C). Can be displayed. By applying the liquid crystal display device described in the above embodiment to the display portion 2705 and the display portion 2707, an electronic book with high contrast, high visibility, and high reliability can be provided. In the case where a transflective or reflective liquid crystal display device is used as the display portion 2705, it is expected to be used in a relatively bright situation. Therefore, a solar cell is provided, and power generation by the solar cell and charging with the battery can be performed. You may do it. In addition, when a lithium ion battery is used as a battery, there exists an advantage, such as achieving size reduction.

FIG. 5C illustrates an example in which the housing 2701 is provided with an operation portion and the like. For example, the housing 2701 is provided with a power supply 2721, operation keys 2723, a speaker 2725, and the like. Pages can be turned with the operation keys 2723. Note that a keyboard, a pointing device, or the like may be provided on the same surface as the display portion of the housing. In addition, an external connection terminal (such as an earphone terminal or a USB terminal), a recording medium insertion portion, or the like may be provided on the rear surface or side surface of the housing. Further, the electronic book may have a structure as an electronic dictionary.

Further, the electronic book may have a configuration capable of transmitting and receiving information wirelessly. It is also possible to adopt a configuration in which desired book data or the like is purchased and downloaded from an electronic book server wirelessly.

FIG. 5D illustrates a mobile phone, which includes two housings, a housing 2800 and a housing 2801. The housing 2801 is provided with a display panel 2802, a speaker 2803, a microphone 2804, a pointing device 2806, a camera lens 2807, an external connection terminal 2808, and the like. The housing 2800 is provided with a solar cell 2810 for charging the mobile phone, an external memory slot 2811, and the like. An antenna is incorporated in the housing 2801. By applying the liquid crystal display device described in the above embodiment to the display panel 2802, the mobile phone can have high contrast, high visibility, and high reliability.

In addition, the display panel 2802 is provided with a touch panel. A plurality of operation keys 2805 that are displayed as images is illustrated by dashed lines in FIG. Note that a booster circuit for boosting the voltage output from the solar battery cell 2810 to a voltage required for each circuit is also mounted.

In the display panel 2802, the display direction can be appropriately changed depending on a usage pattern. In addition, since the camera lens 2807 is provided on the same surface as the display panel 2802, a videophone can be used. The speaker 2803 and the microphone 2804 can be used for videophone calls, recording and playing sound, and the like as well as voice calls. Further, the housing 2800 and the housing 2801 can be slid to be in an overlapped state from the deployed state as illustrated in FIG. 5D, and thus can be reduced in size suitable for carrying.

The external connection terminal 2808 can be connected to an AC adapter and various types of cables such as a USB cable, and charging and data communication with a personal computer are possible. Further, a recording medium can be inserted into the external memory slot 2811 so that a larger amount of data can be stored and moved.

In addition to the above functions, an infrared communication function, a television reception function, or the like may be provided.

FIG. 5E illustrates a digital video camera which includes a main body 3051, a display portion (A) 3057, an eyepiece portion 3053, operation switches 3054, a display portion (B) 3055, a battery 3056, and the like. By applying the liquid crystal display device described in the above embodiment to the display portion (A) 3057 and the display portion (B) 3055, a digital video camera with high contrast, high visibility, and high reliability can be obtained. it can.

FIG. 5F illustrates a television device, which includes a housing 9601, a display portion 9603, and the like. Images can be displayed on the display portion 9603. Here, a structure in which the housing 9601 is supported by a stand 9605 is illustrated. By applying the liquid crystal display device described in the above embodiment to the display portion 9603, a television device with high contrast, high visibility, and high reliability can be provided.

The television device can be operated with an operation switch provided in the housing 9601 or a separate remote controller. Further, the remote controller may be provided with a display unit that displays information output from the remote controller.

Note that the television device 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).

This embodiment can be implemented in appropriate combination with the structures described in the other embodiments.

In this example, bis [4- (3,4,5-trifluorophenyl) phenyl] 1,5-pentanedioic acid represented by the structural formula (101) in Embodiment Mode 1 (abbreviation: BM-3- An example of synthesizing (EPPFFF) is shown.

<Step 1: Synthesis of 3,4,5-trifluoro-4'-hydroxybiphenyl>
11 g (63 mmol) 4-bromophenol, 10 g (58 mmol) 3,4,5-trifluorophenylboronic acid, 0.97 g (3.2 mmol) tris (2-methylphenyl) phosphine, 158 mL Toluene, 158 mL of ethanol, and 63 mL of 2M potassium carbonate aqueous solution were added to the flask, and the mixture was deaerated while being stirred under reduced pressure. After degassing, the atmosphere in the flask was replaced with nitrogen. To this mixture, 0.14 g (0.63 mmol) of palladium (II) acetate was added and stirred at 90 ° C. for 6 hours.

Ethyl acetate and water were added to the obtained mixture, the organic layer was taken out, and the aqueous layer was extracted with ethyl acetate. The obtained extracted solution and the organic layer were combined, washed with water and saturated brine, and dried over magnesium sulfate. This mixture was separated by natural filtration, and the filtrate was concentrated to obtain Celite (Wako Pure Chemical Industries, Ltd., catalog number: 531-1855), alumina, Florisil (Wako Pure Chemical Industries, Ltd., catalog number: 540-00135). And filtered through suction. This mixture was purified by silica gel column chromatography (developing solvent; hexane: ethyl acetate = 5: 1). The obtained fraction was concentrated and vacuum-dried to obtain 8.5 g of a target white solid of 3,4,5-trifluoro-4'-hydroxybiphenyl in a yield of 66%. The synthesis scheme of Step 1 above is shown in (E1-1) below.

<Step 2: Synthesis of bis [4- (3,4,5-trifluorophenyl) phenyl] 1,5-pentanedioate>
1.2 g (8.9 mmol) glutaric acid, 4.0 g (18 mmol) 3,4,5-trifluoro-4′-hydroxybiphenyl, 0.33 g (2.7 mmol) N, N-dimethyl -N- (4-pyridinyl) amine and 8.9 mL of dichloromethane were added to a 50 mL eggplant flask and stirred. To this mixture, 3.8 g (20 mmol) of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride was added, and the mixture was stirred at room temperature for 24 hours. Dichloromethane and water were added to the resulting mixture, the organic layer was taken out, and the aqueous layer was extracted with dichloromethane.

The extracted solution and the organic layer were combined, washed with a saturated aqueous sodium hydrogen carbonate solution and saturated brine, and dried over magnesium sulfate. The mixture was gravity filtered, and the filtrate was concentrated to give a white solid. This solid was purified by silica gel column chromatography (developing solvent: chloroform). The obtained fraction was concentrated to obtain a white solid. This solid was purified by high performance liquid column chromatography (HPLC) (developing solvent; chloroform).

The obtained fraction was concentrated to obtain 4.2 g of a target white solid in a yield of 88%. This solid was purified by sublimation by a train sublimation method. The sublimation purification was performed by heating the white solid at 199 ° C. under the conditions of a pressure of 2.6 Pa and an argon flow rate of 10 mL / min. After purification by sublimation, a white solid of bis [4- (3,4,5-trifluorophenyl) phenyl] 1,5-pentanedioic acid, which was the object, was obtained in a yield of 3.5 g and a recovery rate of 83%. The synthesis scheme of Step 2 above is shown in (E1-2) below.

According to nuclear magnetic resonance (NMR), this compound is the target 1,5-pentanedioic acid bis [4- (3,4,5-trifluorophenyl) phenyl] (abbreviation: BM-3-EPPFFF). I confirmed that there was.

¹ H NMR data of the obtained substance (BM-3-EPPFFF) are shown below. FIG. 6 shows an NMR chart. Note that FIG. 6B is a chart in which the range of 0 ppm to 5.0 ppm in FIG. FIG. 6C is a chart in which the range of 5.0 ppm to 10 ppm in FIG.

¹ H NMR (CDCl ₃ , 300 MHz): δ (ppm) = 2.19-2.28 (m, 2H), 2.78 (t, 4H), 7.12-7.22 (m, 8H), 7.50 (d, 4H).

In this example, bis [4- (3,4,5-trifluorophenyl) phenyl] 1,7-heptanedioate represented by Structural Formula (102) in Embodiment Mode 1 (abbreviation: BM-5 An example of synthesizing (EPPFFF) is shown.

<Step 1: Synthesis of 3,4,5-trifluoro-4'-hydroxybiphenyl>
11 g (63 mmol) 4-bromophenol, 10 g (58 mmol) 3,4,5-trifluorophenylboronic acid, 0.97 g (3.2 mmol) tris (2-methylphenyl) phosphine, 158 mL Toluene, 158 mL of ethanol, and 63 mL of 2M potassium carbonate aqueous solution were added to the flask, and the mixture was deaerated while being stirred under reduced pressure. After degassing, the atmosphere in the flask was replaced with nitrogen. To this mixture, 0.14 g (0.63 mmol) of palladium (II) acetate was added and stirred at 90 ° C. for 6 hours.

Ethyl acetate and water were added to the obtained mixture, the organic layer was taken out, and the aqueous layer was extracted with ethyl acetate. The obtained extracted solution and the organic layer were combined, washed with water and saturated brine, and dried over magnesium sulfate. This mixture was separated by gravity filtration, and the filtrate was concentrated and suction filtered through Celite, alumina, and Florisil. This mixture was purified by silica gel column chromatography (developing solvent; hexane: ethyl acetate = 5: 1). The obtained fraction was concentrated and vacuum-dried to obtain 8.5 g of a target white solid of 3,4,5-trifluoro-4'-hydroxybiphenyl in a yield of 66%. The synthesis scheme of Step 1 is shown in (E2-1) below.

<Step 2: Synthesis of bis [4- (3,4,5-trifluorophenyl) phenyl] 1,7-heptanedioic acid>
1.4 g (8.9 mmol) pimelic acid, 4.0 g (18 mmol) 3,4,5-trifluoro-4′-hydroxybiphenyl, 0.33 g (2.7 mmol) N, N-dimethyl -N- (4-pyridinyl) amine and 8.9 mL of dichloromethane were added to a 50 mL eggplant flask and stirred. To this mixture, 3.8 g (20 mmol) of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride was added, and the mixture was stirred at room temperature for 24 hours. Dichloromethane and water were added to the resulting mixture, the organic layer was taken out, and the aqueous layer was extracted with dichloromethane.

The extracted solution and the organic layer were combined, washed with a saturated aqueous sodium hydrogen carbonate solution and saturated brine, and dried over magnesium sulfate. The mixture was gravity filtered, and the filtrate was concentrated to give a white solid. This solid was purified by silica gel column chromatography (developing solvent: chloroform). The obtained fraction was concentrated to obtain a white solid. This solid was purified by high performance liquid column chromatography (HPLC) (developing solvent; chloroform). The obtained fraction was concentrated to obtain a target white solid in a yield of 4.3 g and a yield of 84%. This solid was purified by sublimation by a train sublimation method. The sublimation purification was performed by heating the white solid at 234 ° C. under the conditions of a pressure of 2.6 Pa and an argon flow rate of 10 mL / min. After sublimation purification, a white solid of bis [4- (3,4,5-trifluorophenyl) phenyl] 1,7-heptanedioic acid, which was the target product, was obtained in a yield of 3.4 g and a recovery rate of 79%. The synthesis scheme of Step 2 above is shown in (E2-2) below.

By nuclear magnetic resonance (NMR), this compound is the target 1,7-heptanedioic acid bis [4- (3,4,5-trifluorophenyl) phenyl] (abbreviation: BM-5-EPPFFF). I confirmed that there was.

¹ H NMR data of the obtained substance (BM-5-EPPFFF) are shown below. FIG. 7 shows an NMR chart. Note that FIG. 7B is a chart in which the range of 0 ppm to 5.0 ppm in FIG. FIG. 7C is a chart in which the range of 5.0 ppm to 10 ppm in FIG.

¹ H NMR (CDCl ₃ , 300 MHz): δ (ppm) = 1.5-1.63 (m, 2H), 1.81-1.91 (m, 4H), 2.64 (t, 4H), 7.10-7.19 (m, 8H), 7.49 (d, 4H).

In this example, a liquid crystal composition containing the organic compound according to one embodiment of the present invention synthesized in Example 1 and Example 2 and a liquid crystal composition not containing the organic compound according to the present invention were used as comparative examples. A liquid crystal element was produced and its characteristics were evaluated.

In this example, a liquid crystal element (Example Sample 1) using the liquid crystal composition containing BM-3-EPPFFF represented by Structural Formula (101) synthesized in Example 1 and the structure synthesized in Example 2 were used. Liquid crystal element using the liquid crystal composition containing BM-5-EPPFFF represented by the formula (102) (Example sample 2), and liquid crystal element using the liquid crystal composition to which no organic compound according to the present invention is added (Comparative Example Sample 1) was produced. The configuration of the liquid crystal composition used in Example Sample 1 is shown in Table 1, the configuration of the liquid crystal composition used in Example Sample 2 is shown in Table 2, and the configuration of the liquid crystal composition used in Comparative Example Sample 1 is shown in Table 3. Each is shown. In Tables 1 to 3, all ratios (mixing ratios) are expressed as weight ratios.

In Example Sample 1, Example Sample 2, and Comparative Sample 1, mixed liquid crystal E-8 (manufactured by LCC Co., Ltd.), 4- (trans-4-n-propylcyclohexyl) -3 ′, 4′- was used as the liquid crystal. Difluoro-1,1′-biphenyl (abbreviation: CPP-3FF), 3-fluoro-4-cyanophenol cyanophenyl (abbreviation: PEP-5CNF), 1,4: 3,6-dianhydro-2,5 as a chiral agent -Bis [4- (n-hexyl-1-oxy) benzoic acid] sorbitol (abbreviation: ISO- (6OBA) ₂ ) (manufactured by Midori Chemical Co., Ltd.), 1,4-bis- [4- ( 4-acryloyloxy-n-hexyl-1-oxy) benzoyloxy] -2-methylbenzene (abbreviation: RM257-O6) (manufactured by Synton Chemicals Co., Ltd.), non-liquid crystalline mono Over as dodecyl methacrylate (abbreviation: DMeAc) (manufactured by Tokyo Kasei Kogyo Co., Ltd.), was used DMPAP (abbreviation) (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a polymerization initiator.

Further, Example Sample 1 uses BM-3-EPPFFF represented by Structural Formula (101) as the liquid crystal, and Example Sample 2 uses BM-5-EPPFFF represented by Structural Formula (102) as the liquid crystal. Each was used.

The structural formula of the organic compound used in the liquid crystal composition of this example is shown below.

Example Sample 1, Example Sample 2, and Comparative Example Sample 1 are composed of a glass substrate in which a pixel electrode layer and a common electrode layer are formed in a comb-like shape as shown in FIG. After being bonded together with a sealing material with a gap (4 μm) in between, each liquid crystal composition stirred in an isotropic phase was injected between the substrates by an injection method.

The pixel electrode layer and the common electrode layer were formed by sputtering using indium tin oxide containing silicon oxide (ITSO). 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 2 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.

After making the liquid crystal compositions of the liquid crystal elements of Example Sample 1, Example Sample 2 and Comparative Example Sample 1 into an isotropic phase, the liquid crystal composition is observed in a blue phase while being cooled with a temperature controller and observed with a polarizing microscope. Measurement of the temperature range that expresses.

Example Sample 1 developed a blue phase in the temperature range of 31.2 ° C. to 36.4 ° C., Example Sample 2 developed a blue phase in the temperature range of 31.0 ° C. to 36.0 ° C., and Comparative Example In sample 1, a blue phase developed in the temperature range of 33.5 ° C. to 40.9 ° C.

Next, in order to widen the temperature range where the blue phase appears, each liquid crystal element was subjected to polymer stabilization treatment. The conditions of the polymer stabilization treatment are as follows: in each of Example Sample 1, Example Sample 2 and Comparative Example Sample 1, the blue phase appears from a temperature 3 ° C. higher than the maximum temperature at which the blue phase appears (maximum temperature + 3 ° C.) The temperature is kept constant at an arbitrary temperature within the minimum temperature range, and the light from the ultraviolet lamp is irradiated for 6 minutes at an irradiance of 12 mW / cm ² through a short wavelength cut filter that cuts a wavelength of 350 nm or less. A molecular stabilization treatment was performed. By the polymer stabilization treatment, the polymerizable monomers contained in the liquid crystal compositions of Example Sample 1, Example Sample 2 and Comparative Example Sample 1 were polymerized, and Example Sample 1, Example Sample 2 and Comparative Example were polymerized. Sample 1 is a liquid crystal element having a liquid crystal composition containing an organic resin.

Next, the spectrum of the reflected light intensity of the liquid crystal compositions contained in Example Sample 1, Example Sample 2 and Comparative Example Sample 1 having the liquid crystal composition subjected to the polymer stabilization treatment was measured. For the measurement, a polarizing microscope (MX-61L manufactured by Olympus Corporation) and a microspectroscopic system (LVmicroUV / VIS manufactured by Lambda Vision Co., Ltd.) were used. Moreover, the measurement was performed at room temperature (20 degreeC).

In the measurement of the spectrum of the reflected light intensity of this example, the measurement mode of the microspectroscopic system was the reflection mode, the polarizer was crossed Nicol, the measurement region was 12 μmφ, and the measurement wavelength was 250 nm to 800 nm. Since the measurement range is narrow, the region where the blue phase color has a long wavelength is selected on the monitor of the microspectroscopy system. Note that the measurement was performed from the glass substrate side which is the counter substrate on which the electrode layer is not formed so as not to be affected by the pixel electrode layer and the common electrode layer at the time of measurement.

In FIG. 8, the spectrum of the reflected light intensity of the liquid crystal composition contained in each of Example Sample 1, Example Sample 2, and Comparative Example Sample 1 is shown. In the reflection spectrum of the liquid crystal composition, a diffraction wavelength peak was detected. The peak of the diffraction wavelength in the detected reflection spectrum is the maximum value of the peak that appears on the longest wavelength side.

From FIG. 8, the peak of the diffraction wavelength on the longest wavelength side in the reflection spectra of Example Sample 1 and Example Sample 2 which is one embodiment of the present invention is 492 nm in Example Sample 1 and 494 nm in Example Sample 2. Met. On the other hand, in Comparative Sample 1 that does not contain the organic compound according to one embodiment of the present invention, the peak of the diffraction wavelength on the longest wavelength side in the reflection spectrum was 545 nm. Therefore, in Example Sample 1 and Example Sample 2 which is one embodiment of the present invention, it was confirmed that the peak of the diffraction wavelength on the longest wavelength side in the reflection spectrum is located on the shorter wavelength side. That is, it was shown that the liquid crystal composition according to one embodiment of the present invention is a liquid crystal composition with strong twisting power. When the twisting force of the liquid crystal composition is strong, the transmittance of the liquid crystal composition when no voltage is applied (when the applied voltage is 0 V) can be kept low, so that the liquid crystal display device using the liquid crystal composition has high contrast. Is possible.

Therefore, when the liquid crystal composition exhibiting a blue phase of this embodiment which is one embodiment of the present invention is used, a liquid crystal display device which can achieve higher contrast can be provided.

200 substrate 201 substrate 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 2701 Housing 2703 Housing 2705 Display Part 2707 Display part 2711 Shaft part 2721 Power supply 2723 Operation key 2725 Speaker 2800 Case 2801 Case 2802 Display panel 2803 Speaker 2804 Microphone 2805 Operation key 2806 Poi Tinging device 2807 Camera lens 2808 External connection terminal 2810 Solar cell 2811 External memory slot 3001 Main body 3002 Case 3003 Display unit 3004 Keyboard 3021 Main unit 3022 Stylus 3023 Display unit 3024 Operation button 3025 External interface 3051 Main unit 3053 Eyepiece unit 3054 Operation switch 3056 Battery 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 Transistor 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-shielding layer 9601 Housing 9603 Display portion 9605 Stand

Claims (7)

An organic compound represented by the following general formula (G1).

(In General Formula (G1), Ar ¹ represents a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 4 to 12 carbon atoms, or a substituted or unsubstituted carbon number 3 Represents any of 1 to 12 cycloalkenyl groups, and m is an integer of 1 to 3. R ¹ represents a substituted or unsubstituted alkylene group having 1 to 11 carbon atoms. A liquid crystal composition containing the organic compound according to claim 1. A liquid crystal composition containing the organic compound according to claim 1 and a chiral agent and exhibiting a blue phase. 4. The liquid crystal composition according to claim 3, wherein the peak of the diffraction wavelength on the longest wavelength side in the reflection spectrum is 500 nm or less. The liquid crystal element using the liquid-crystal composition as described in any one of Claims 2 thru | or 4. A liquid crystal display device using the liquid crystal composition according to claim 2. The liquid crystal display device according to claim 6, wherein the liquid crystal composition includes an organic resin.