JPH06347775A - Liquid crystal element and liquid crystal device using the same - Google Patents

Abstract

PURPOSE:To provide a liquid crystal element which has an excellent function to shut off light in particular and is adequately used in applications where a light transmission-shut off function is demanded and a liquid crystal device using this element. CONSTITUTION:This liquid crystal element L is constituted by arranging a selective reflection member 1 which reflects only the incident light of a specific angle range in a ray incident direction and allows the transmission of the incident light at other angles in a ray emission direction on the ray exit side of a liquid crystal layer 20. The liquid crystal device is constituted by arranging a ray adjusting member on the ray incident side of the liquid crystal element L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal element and a liquid crystal device used for light control of a light control window, a display device, or a lighting device.

[0002]

2. Description of the Related Art Liquid crystal elements such as TN type, STN type and FLC type require a polarizer, and it is difficult to increase the light utilization rate because the loss due to the polarizer is 50% or more.
Further, when the liquid crystal element of each of the above methods is used as a light control element of an illuminating device using a light source with a large amount of light, there is a problem that heat generation due to light absorption of the polarizer cannot be avoided.

On the other hand, a structure in which a liquid crystal material is filled in the continuous pores of a carrier film made of a transparent matrix having a three-dimensional mesh structure, or the liquid crystal material is granular in a carrier film made of a transparent matrix. Since the liquid crystal element in which the composite film having the structure dispersed in is sandwiched between the transparent substrates having the pair of transparent conductive films does not require a polarizer, the above problem can be solved.

In the above liquid crystal element, when no voltage is applied,
Since the liquid crystal molecules are in a random state due to the shape regulation (interface action) of the interface between the liquid crystal molecules and the transparent matrix, incident light is scattered and the composite film is in an opaque state. . Then, when a voltage (for example, a rectangular wave or a sine wave of about 200 Hz) is applied between the transparent substrates having a pair of transparent conductive films sandwiching the composite film, a positive dielectric constant is generated according to the magnitude of the applied voltage. Liquid crystal molecules with index anisotropy (Δε) are aligned in the direction of the electric field, the disorder of the alignment is gradually resolved, the light transmittance increases, and finally the electro-optical effect is achieved. . Note that the transmittance here refers to the ratio of the amount of light that passes through and exits from the element with respect to the amount of light that enters the element. In the case of a light-scattering liquid crystal element, collimated parallel light rays are entered into the element. At this time, it is represented by the ratio of the emitted light amount within a certain angle range. The angle may be determined according to the usage of the element. Here, the light transmitted within the angle range is defined as non-scattered light.

[0005]

When the above liquid crystal element is brought into the light scattering state, a part of the incident light is backscattered in the light ray incident direction, but the rest is scattered in the light ray outgoing direction and transmitted through the element. I will end up. Therefore, the liquid crystal element has a problem that the function of blocking light is insufficient. Therefore, in order to use the liquid crystal element in a high-brightness display device or in an application requiring a function of light transmission-blocking, such as dimming of a lighting device, a louver is arranged on the light emitting side, It becomes necessary to remove the scattered light that has passed through or to arrange the louver on the light incident side to regulate the incident direction of the incident light, which limits the visual range of the display and reduces the light utilization efficiency. It was the cause.

The present invention has been made in view of the above circumstances, and is particularly excellent in the function of blocking light, and is light-transmitting.
It is an object of the present invention to provide a liquid crystal element that is preferably used in applications that require a blocking function, and a liquid crystal device that uses the liquid crystal element.

[0007]

In the liquid crystal device of the present invention for solving the above-mentioned problems, light incident at an angle in the vicinity of the normal direction is reflected in the incident direction of a light beam and incident at another angle. The plate-shaped selective reflection member that transmits the light in the light emission direction is arranged on the light emission side of the liquid crystal layer that transmits and scatters the light according to the applied voltage.

According to the liquid crystal element of the present invention having the above-mentioned structure, when the liquid crystal layer is brought into the light transmitting state, the light transmitted through this liquid crystal layer is reflected by the liquid crystal layer to the selective reflection member,
Since the light mainly enters at an angle near the normal direction, it is reflected in the light incident direction by the action of the selective reflection member. Therefore, the element is in a light blocking state. On the other hand, when the liquid crystal layer is set to the light scattering state, the light scattered by the liquid crystal layer is mainly incident on the selective reflection member at an angle other than the angle in the vicinity of the normal direction thereof, and therefore the light is transmitted through the selective reflection member. The light is emitted in the light emission direction. Therefore, the element is in a light transmitting state.

Further, the liquid crystal device of the present invention is arranged on the above-mentioned liquid crystal element of the present invention and on the light ray incident side of this liquid crystal element, and the incident angle of the light ray incident on the liquid crystal element is within the ray reflection angle of the selective reflection member. And a light beam adjusting member for adjusting. Due to the above-mentioned mechanism, it is desirable that the light incident on the liquid crystal element of the present invention is light adjusted within the light reflection angle of the selective reflection member. The liquid crystal device of the present invention includes a light ray adjusting member that adjusts the light rays incident on the liquid crystal element within the light ray reflection angle of the selective reflection member. The light transmission-blocking function (particularly the light blocking function) can be more efficiently exhibited.

The present invention will be described below. First, the liquid crystal element of the present invention will be described. The liquid crystal element of the present invention is, for example, as shown in FIGS. 1 (a) and 1 (b), a liquid crystal cell 2 including a liquid crystal layer 20 that transmits and scatters light in accordance with an applied voltage, and the light emission of the liquid crystal cell 2. And a plate-shaped selective reflection member 1 disposed on the side.

The selective reflection member 1 has a smooth surface 10 on the liquid crystal cell 2 side (light ray incident side) and an opposite side (light ray outgoing side).
A transparent plate having an uneven surface 11 is used. As shown in FIGS. 2 (a) and 2 (b), the uneven surface 11 has a large number of inclined surfaces 11a inclined at a predetermined angle with respect to the smooth surface 10 (the prism angle ∠θa in FIG. It is composed by arranging.

In the selective reflection member 1, the incident light refracted on the smooth surface 10 is inclined at an incident angle exceeding the critical angle of refraction and reflection on the inclined surface 11a (∠θy in FIGS. 2A and 2B). Surface 1
When reaching 1a, the arrows R and R'in the dashed line in FIG.
When the light reaches the inclined surface 11a at an incident angle within the critical angle (∠θy) as shown in Fig. 4, it is used that it passes through the inclined surface 11a as shown by the dashed line arrow r in Fig. 6 (b). Then, the light is selectively transmitted and reflected.

The operation of the selective reflection member 1 will be described in more detail. As shown in FIG. 2 (a), from the normal direction of the selective reflection member 1 (two-dot chain line V in the figure), θx, θ to the left and right in the figure
The light R that reaches the selective reflection member 1 at an incident angle ∠θb (∠θb <∠θx) within the range that can be selectively reflected by the selective reflection member 1 indicated by the angle x is the dashed line in the figure. Is refracted on the smooth surface 10 as indicated by the arrow, and enters the inclined surface 11a at an incident angle ∠θd (∠θd> ∠θy) exceeding the critical angle ∠θy, and the inclined surface 11a and the adjacent inclined surface 11a. The light is totally reflected twice by 11a and is returned to the light ray incident side (the liquid crystal cell 2 side) again. In the figure, the light R'on the right side is
A direction that coincides with the normal line V of the selective reflection member 1 (that is, ∠θ
Light incident from b = 0 ° is shown. This light R '
Is the incident angle ∠θ that exceeds the critical angle ∠θy
Since the light is incident on the inclined surface 11a at d '(∠θd'> ∠θy), it is totally reflected twice by this inclined surface 11a and the adjacent inclined surface 11a and is returned to the light incident side (the liquid crystal cell 2 side) again. Be done.

On the other hand, in FIG. 2 (b), the one-dot chain line arrow indicates
Incident angle ∠θc (∠θc> ∠) outside the range that can be selectively reflected
The light r that has reached the selective reflection member 1 at θx) is refracted by the smooth surface 10 as indicated by the dashed-dotted arrow in FIG.
Incident angle ∠θe (∠θe <∠θ within the critical angle ∠θy
In y), the light is incident on the inclined surface 11a, passes through the inclined surface 11a, and is emitted to the light emitting side.

In the selective reflection member 1, as is clear from the principle of geometrical optics, the range of the incident angle (∠θx) of light that can be selectively reflected is that of the transparent plate that constitutes the selective reflection member 1. Refractive index and prism angle of inclined surface 11a ∠θ
It is determined by a and. For example, when the selective reflection member 1 is made of acrylic resin having a refractive index of 1.49 and the prism angle ∠θa of the inclined surface 11a is set to 45 °, the above ∠θ
x becomes about 3 °, and when the selective reflection member 1 is formed of a polycarbonate resin having a refractive index of 1.58 and the prism angle ∠θa of the inclined surface 11a is also set to 45 °, ∠θx becomes about 10 °. Become.

The prism angle ∠θa is not always the value shown in FIG.
It does not need to be symmetrical as in (b), and may be ∠θa ≠ ∠θa 'as shown in FIG. Also, the vertical angle ∠θ
It is preferable that f is a right angle, but it need not be a right angle if the optical arrangement is devised. Therefore, the prism angles ∠θa, ∠θa ′, the apex angle ∠θf, and the refractive index of the transparent plate may be set to appropriate values according to the usage of the display device.

As the selective reflection member 1, a glass plate,
A hard transparent plate such as an acrylic plate can be used, and a flexible and highly transparent resin plate such as polycarbonate can also be used to make the display device flexible. As such a flexible selective reflection member,
Product name SOLF (Scotch Optical LightingF) manufactured by 3M
ilm, refractive index 1.62, prism angle ∠θa = 45 °,
An uneven prism pitch p = 0.25 mm, made of polycarbonate) is commercially available.

In the case of FIGS. 1 (a) and 1 (b), the liquid crystal cell 2 constituting the liquid crystal element together with the selective reflection member 1 has the liquid crystal layer 2 described above.
0 is sandwiched between a pair of transparent base materials 21. Each of the transparent base materials 21 includes a transparent electrode layer 21a on the surface on the liquid crystal layer 20 side. As the liquid crystal layer 20, the above-described composite film is preferably used from the viewpoint of increasing the area of the element and imparting flexibility, and also includes a liquid crystal polymer, a low molecular weight liquid crystal material, and a minute amount of electrolyte. A mixed film containing the same is also preferably used from the same viewpoint. In addition, various liquid crystal systems having a light scattering-transmitting function (for example, DSM mode, Ch
Phase transition mode, etc.) can also be adopted.

The composite film of the liquid crystal layer 20 is shown in FIG.
As shown in (a), a structure in which a liquid crystal material 20b is filled in continuous holes of a carrier film 20a made of a transparent matrix having a three-dimensional mesh structure, or as shown in FIG. Any of the structures in which the liquid crystal material 20b is dispersed in the carrier film 20a made of a matrix in a granular form is adopted. As described above, the composite film having any one of the above structures is in a random state because the liquid crystal molecules in the pores are subjected to the interfacial action from the transparent matrix at the time of no voltage,
It is in a light-scattering state in which incident light is scattered. And
When a voltage is applied to the composite film in this state, depending on the magnitude of the applied voltage, a positive dielectric anisotropy [Δε> 0, where Δε is a dielectric anisotropy,

[0020]

[Equation 1]

Is represented by (note that

[0022]

[Outer 1]

Is the dielectric constant in the molecular axis direction,

[0024]

[Outside 2]

Represents the dielectric constant in the direction orthogonal to the molecular axis. ] Are aligned in the direction of the electric field, the disorder of the alignment is gradually eliminated, and the incident light can pass without being scattered, and the electro-optical effect is obtained. The liquid crystal material forming the composite film is not particularly limited, but the refractive index anisotropy Δn and the dielectric constant anisotropy Δε.
It is preferable to use one having a large value in order to obtain good characteristics. As the liquid crystal material, materials showing various conventionally known liquid crystal phases such as nematic liquid crystal, smectic liquid crystal and chiral nematic liquid crystal can be used. Examples of the chiral nematic liquid crystal include cholesteric liquid crystal, and ordinary nematic liquid crystal in which a chiral component such as the above cholesteric liquid crystal is blended. Further, as the above-mentioned liquid crystal material, it is preferable to use a material having a high-speed response capable of performing an operation from a light scattering state to a transparent state in response to an applied voltage or vice versa in a short time. The liquid crystal material may be blended with various conventionally known dichroic dyes in order to color the display. Such liquid crystal materials may be used alone or in combination of two or more.

Polymers are mainly used as the transparent matrix, which is the material of the carrier film forming the composite film together with the liquid crystal material. As the polymer, those having high transparency to visible light are preferable, and for example, (meth) acrylic polymer represented by PMMA, epoxy resin, urethane resin and the like are preferably used. In order to impart flexibility, it is preferable to select and use one having higher flexibility among the various polymers mentioned above. The transparent matrix is not limited to a polymer, and may be made of a transparent inorganic material such as glass or a dispersion of this in a polymer.

Further, in the polymer constituting the transparent matrix, the adhesiveness of the composite film to the transparent electrode layer is improved to prevent the positional displacement and peeling of the two, thereby increasing the area of the liquid crystal element and making it flexible. An adhesive polymer or a tacky polymer may be used in combination for further facilitating the imparting of properties. As the adhesive polymer and the tacky polymer, it is preferable to use those having excellent compatibility with the matrix polymer in order to maintain the transparency of the matrix polymer. For example, as the matrix polymer, PMMA is used. In the case of using, a (meth) acrylic adhesive polymer or adhesive polymer is preferably used.

The film thickness of the composite film needs to be equal to or more than the wavelength of visible light in order to obtain sufficient light scattering. However, when the thickness is too large, there is a problem that the driving voltage of the element becomes too high, so in practice about 10 to 30 μm is appropriate. The composite film is formed by, for example, the following three methods. i) For example, when the transparent matrix is composed of a polymer,
The coating liquid prepared by dissolving or dispersing the polymer and the liquid crystal material in a suitable solvent is used as the transparent electrode layer 2 of one transparent substrate 21.
It is applied to the surface on which 1a is formed, the solvent is evaporated, and the polymer and the liquid crystal material are phase-separated (so-called solvent evaporation method). Then, a composite film having the structure shown in FIG. 4 (a) is obtained.

Ii) In the suspension method, a milky solution in which a hydrophilic polymer such as polyvinyl alcohol is mixed with a liquid crystal material is applied to the surface of the transparent electrode layer 21a of one transparent base material 21 and water in the solution is applied. Are evaporated and the liquid crystal material is dispersed in the polymer in a granular form to form a composite film having the structure shown in FIG. 4 (b). iii) In the polymerization phase separation method, a solution in which a polymer precursor (prepolymer), a liquid crystal material and a polymerization initiator are mixed is injected between the transparent electrode layers 21a of the two transparent base materials 21, and ultraviolet light is emitted. Alternatively, a polymerization and a crosslinking reaction are caused by heat,
The phase separation of the polymer and the liquid crystal material forms a composite film having the structure shown in FIG. 4 (a).

The mixed film in the liquid crystal layer 20 is composed of a liquid crystalline polymer, a low molecular weight liquid crystal material, and a minute amount of an electrolyte [JP-A-2-193115 and JP-A-2-127].
494, Chem. Lett., 817 (1989), Polym.Prepr.
ints, Japan 39 (8) 2373 (1990), etc.]. When a low-frequency or direct-current electric field is applied to the mixed film, ions present in a very small amount in the film move together with the electric field and collide with the main chain of the liquid crystalline polymer to disturb the alignment of the liquid crystal, and thus the mixed film is incident. The light is strongly scattered and becomes in a light scattering state. On the other hand, when a high-frequency electric field is applied to the mixed film, the liquid crystal molecules in the film are homeotropically oriented in the electric field direction so that the incident light can pass through without being scattered and is converted into a light transmitting state. Since the operation of light transmission ⇔ light scattering occurs based on this operating principle,
The mixed film does not require any alignment treatment on the surface of the base material, which is used in a normal TN liquid crystal or the like. Further, this mixed film has a memory property of stably holding the light scattering state or the non-scattering state when the electric field is removed in both the above states.

As the liquid crystalline polymer that constitutes the mixed film,
Various main chain-type or side chain-type liquid crystalline polymers can be used. Particularly, the side chain type of a polymer in which a side chain liquid crystalline group consisting of a spacer portion and a mesogenic group is grafted Those are preferably used. The chemical structure of the main chain constituting the side chain type liquid crystalline polymer may be arbitrary, but it is preferable that the main chain contains a flexible structure to some extent, and examples thereof include, but are not limited to, for example, Examples include oxetane chains, polysiloxane chains, polymethacrylate chains, polyacrylate chains, polyoxyethylene chains, polychloroacrylate chains and polyester chains.

Examples of the spacer portion constituting the side chain liquid crystalline group of the side chain type liquid crystalline polymer include alkylene chains (methylene chains etc.), oxyalkylene chains, siloxane chains, ester chains, ether chains, oxetane chains and butadiene. Examples of the mesogen group include various conventionally known mesogen groups corresponding to the chemical structure of the core of a normal liquid crystal material. The graft ratio of the side chain liquid crystalline group is arbitrarily set.

Since the conditions such as the structure of the liquid crystalline polymer, the average molecular weight, and the molecular weight distribution have a great influence on the characteristics of the device, these conditions should be appropriately set according to the required characteristics of the device. Good. For example, the liquid crystalline polymer may have a crosslinked structure. The crosslinked liquid crystalline polymer enhances the self-holding property of the entire system and rapidly transmits the disorder of the liquid crystal alignment caused by the movement and collision of the electrolyte when a direct current or low frequency electric field is applied. Improve the responsiveness of. The cross-linking of the liquid crystalline polymer may be carried out directly between the main chains or via a suitable cross-linking agent. In the case of a side chain type liquid crystalline polymer, the main chains may be crosslinked with each other via a side chain liquid crystalline group. The bond structure for crosslinking may be any chemical bond (covalent bond, ionic bond, hydrogen bond, coordinate bond, etc.).

The liquid crystalline polymer has a molecular weight of 10 for example.
It may be an oligomer of about 000 or less. These liquid crystalline polymers may be used alone or in combination of two or more. Low molecular weight (“low molecular weight” here means that it does not have the main chain structure and side chain structure like liquid crystalline polymer, and is not defined by molecular weight at all) As a material, various liquid crystal materials that are commercially available or publicly known, and are composed of a single component or a plurality of components, excluding main chain type or side chain type liquid crystalline polymers (for example, nematic liquid crystal, smectic liquid crystal, chiral smectic) are used. LCD etc.) can be used.

As the physical properties of the low molecular weight liquid crystal material, those having a large dielectric anisotropy Δε and those having a large refractive index anisotropy Δn are preferable. Further, as a particularly important factor, it is possible to show a smectic phase in the operating temperature range of the device when mixed with a liquid crystalline polymer. As a result, the mixed film has the memory property as described above. Such liquid crystal materials may be used alone or in combination of two or more.

The compounding ratio of the low-molecular liquid crystal material is not particularly limited, but the ratio of the low-molecular liquid crystal material in the total liquid crystal is preferably in the range of 40 to 95% by weight, 6
More preferably, it is in the range of 0 to 90% by weight. If the proportion of the low-molecular liquid crystal material is less than the above range, the response speed of the device may be slowed. Conversely, if the proportion of the low-molecular liquid crystal material exceeds the above range, the main chain is bombarded with ions. The probability becomes small, the transition from transparent to cloudy may be less likely to occur, and the self-supporting property of the mixed film becomes insufficient, so that a flexible large-area liquid crystal using a flexible substrate is used. There is a possibility that the element cannot be constructed.

A minute amount of electrolyte is mixed in the mixed film. Any electrolyte can be used as long as it can be dissolved in the liquid crystal material. For example, the general formula (1):

[0038]

[Chemical 1]

(Where R¹, R², R³, R^FourAre the same or
Are different from straight-chain or branched C1-C6 al
Represents a kill group, and Yo is F, Cl, Br, I, ClO_Four, P
F_Four, BF _FourEtc. ) Quaternary ammonium represented by
Salts are preferred. The amount of electrolyte added is
About 0.05 to 1% by weight is preferable with respect to the total amount of the mixed film.
Yes. Even if one type of electrolyte is used alone, two types of such electrolytes are used.
You may use together the above.

Various known dichroic dyes can be added to the mixed film composed of the above components in order to color the display. Further, the mixed film may be mixed with various additives, a non-liquid crystal compound, or the like within a range that does not impair the property, to adjust the property. Further, in the mixed film, in order to keep the distance between the pair of base materials holding the mixed film constant, a spacer material made of silica, glass fiber or resin and having any shape such as granular or needle-like shape is used. It can also be mixed and dispersed. The particle size of the spacer material is set according to the desired distance between the base materials (that is, the film thickness of the mixed film). The mixing ratio of the spacer material is not limited to this, but it is desirable that it is about 10 to 300 per 1 mm ^{2 of} liquid crystal area.

The mixture of the above-mentioned components used as a material for the mixed film has a relatively high viscosity because it contains a liquid crystalline polymer, so that the spacer material is localized by the flow of the liquid crystal. There is no fear. Therefore, the spacer material is uniformly dispersed in the mixed film, and acts sufficiently to keep the distance between the base materials constant. Although the thickness of the mixed film is not particularly limited in the present invention, it is about 1 to 30 μm.
It is preferable in terms of device contrast and driving voltage.

The mixed film can be manufactured by various manufacturing methods. For example, when a flexible material such as a film is used as the transparent base material 21 as described later, it is obtained by dissolving each of the above components in an appropriate solvent, dispersing the spacer material, and then drying. A so-called laminating method in which a paste-like mixture is placed on one transparent base material 21, the other transparent base material 21 is overlaid thereon and laminated by a laminating roll, is preferably used.

When a glass base material or a hard plastic base material is used, a method of forming a mixed film by injecting the above mixture between a pair of transparent base materials 21 held at a constant distance, or one of them is used. A method of applying a coating solution prepared by dissolving each of the above components in a suitable solvent onto the surface of the transparent substrate 21 and drying and solidifying the coating solution to form a mixed film is used. In the former case, as a method of injecting the mixture between the transparent base materials 21,
Examples thereof include a method of impregnating the mixture between the transparent base materials 21 by a capillary phenomenon, and a method of sucking the mixture by reducing the pressure between the transparent base materials 21. When injecting the mixture between the transparent base materials 21 by these methods, the viscosity may be lowered by heating the mixture in order to smoothly perform the injection. At the same time, the transparent base material 21 may be heated. The heating temperature of the mixture and the transparent base material 21 is not particularly limited, and may be a temperature range in which the liquid crystalline polymer, the polymer material, and the like are not decomposed or deteriorated, and the temperature at which the injection is smooth.

In the latter case, the coating solution is applied to the transparent substrate 21.
As a method for applying to the surface of the above, various conventionally known applying methods such as a bar coating method, a spin coating method, a spray coating method and a roller coating method can be adopted. As the transparent base material 21 for sandwiching the liquid crystal layer 20, various base materials conventionally used as a base material for liquid crystal elements such as a glass plate can be used, but the drawback of the glass plate is that it is heavy and easily broken. In order to solve the above problem and obtain a lightweight and durable element, a plastic film or a plastic plate is preferably used as the base material.

Examples of the plastic film include polyethylene terephthalate (PET) film and polyether sulfone (PES) film which are excellent in heat resistance, practical strength and optical uniformity. The thickness of the plastic film is not limited to this, but is preferably about 50 to 500 μm. As the plastic plate, for example, various acrylic resin plates, polycarbonate plates, polystyrene plates, and other plastic plates having excellent optical characteristics are preferably used. The thickness of the plastic plate is not limited to this, but is 0.5 to 3
mm is preferable.

As the transparent electrode layer 21a formed on the surface of the transparent substrate 21, a transparent conductive film made of a transparent conductive material such as ITO (Indium-Tin-Oxide) or SnO ₂ is preferably used. The transparent conductive film may be formed by a vacuum deposition method or a reactive sputtering method, or may be formed by applying or printing an ink containing the transparent conductive material on a substrate. When the liquid crystal element of the present invention is used in, for example, a display device or various kinds of illuminations, the above electrode layer is used to divide the liquid crystal layer into a plurality of individually driven segments according to the display pattern. Is patterned into a predetermined shape corresponding to the segment by etching or the like, and a drive circuit may be connected so that an individual drive voltage can be applied to each segment.

In the liquid crystal element L composed of the above parts, when the liquid crystal layer 20 is set in the light transmitting state as shown in FIG. 1 (a),
The light transmitted through the liquid crystal layer 20 is incident on the selective reflection member 1 mainly at an angle in the vicinity of the normal direction due to the polarization action of the liquid crystal layer 20, and is reflected in the light ray incident direction by the action of the selective reflection member 1. It Therefore, the liquid crystal element L is in a light blocking state.

On the other hand, when the liquid crystal layer 20 is brought into a light scattering state as shown in FIG. 1 (b), the light scattered by the liquid crystal layer 20 is reflected on the selective reflection member 1 mainly at angles other than the angle in the vicinity of its normal direction. Since the light is incident at an angle of, the light passes through the selective reflection member 1 and is emitted in the light emitting direction. Therefore, the liquid crystal element L is in a light transmitting state. Next, the liquid crystal device of the present invention will be described.

The liquid crystal device of the present invention adjusts the incident angle of the light ray incident on the liquid crystal element L on the light incident side of the liquid crystal element L of the present invention within the light reflection angle of the selective reflection member 1. It is configured by arranging members. As the light beam adjusting member, the louver 30 shown in FIG.
The collimating lens 31 and the like shown in (b) are exemplified. Both can be used together.

Since the liquid crystal device of the present invention is provided with the light beam adjusting members such as the louver 30 and the collimator lens 31 for adjusting the light beam incident on the liquid crystal element L within the light beam reflection angle of the selective reflection member 1, the liquid crystal is provided. The drive power source D is connected to the pair of transparent electrode layers 21a of the cell 2 and the light transmission-blocking function (particularly the light blocking function) by the liquid crystal element L of the present invention is more efficiently provided by simply combining it with the normal light source K. It can be demonstrated well.

The configurations of the liquid crystal element and the liquid crystal device of the present invention are not limited to the examples shown in the drawings. For example, if the transparent electrode layer formed on the smooth surface 10 of the selective reflection member 1 is replaced with one of the transparent base materials 21 constituting the liquid crystal cell 2, the structure of the element can be further simplified. In addition, various design changes can be made without departing from the scope of the present invention.

[0052]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples. Example 1 <Preparation of Liquid Crystal Cell> 70 parts by weight of nematic liquid crystal material [crystal phase → nematic phase transition temperature 15 ° C., nematic phase → isotropic phase transition temperature 172 ° C., manufactured by Merck Japan Ltd.] and acrylic polymer material 25 Parts by weight and 5 parts by weight of polyisocyanate as a cross-linking agent were dissolved in dichloromethane as a solvent to a solute concentration of 20% to prepare a coating solution [the above acrylic polymer material is It is an acrylic acid ester copolymer containing 20% by weight of hydroxyethyl methacrylate as a body component, and is crosslinked by the reaction between the OH group of the side chain of hydroxyethyl methacrylate and the isocyanate group of polyisocyanate].

Next, the above coating solution is applied onto the transparent electrode layer of the glass substrate having a transparent electrode layer formed on the surface thereof by the bar coating method, and the solvent is evaporated in the air at 25 ° C. and 1 atm. Then, the thickness 17 having the phase separation structure shown in FIG.
After forming the composite film of μm, the solvent remaining in the film was removed by heating at 100 ° C. and the crosslinking of the polymer matrix forming the carrier film was completed.

Then, the same glass substrate as above was laminated on the above composite film so that the transparent electrode layer was in contact with the composite film, and pressed at a pressure of about 1 kgf / cm ² to be in close contact, thereby producing a liquid crystal cell. did. <Production of Liquid Crystal Element> Selective reflection member 1 having a sectional shape shown in FIGS. 2 (a) and 2 (b) [prism angle ∠θa = 45 °, prism pitch 0.25 mm, thickness 1.0 mm, refractive index 1.62,
Product name SOLF (Scot made by Polycarbonate, 3M)
ch Optical Lighting Film)] is arranged on the light emitting side of the liquid crystal cell 2 with a space of 0.1 mm, and
A liquid crystal element having the configuration shown in (a) and (b) was produced. <Measurement of operation> The liquid crystal element is vertically irradiated with a spotlight (luminance 9500 cd / m ² ) from the light incident side (the liquid crystal cell side, the right side in FIGS. 1A and 1B) of the liquid crystal element, The element surface luminance of the liquid crystal element was measured by a luminance meter arranged on the emitting side (selective reflection member side, left side in FIGS. 1 (a) and 1 (b)), and the element surface luminance at a cell voltage of 0 V was 3200 cd / m 2. ² , the device surface luminance at a cell voltage of 100 V is 200 cd / m ² , and the contrast expressed by the ratio of the ^two device surface luminances is 3200/200 = 16, which has a light transmission-blocking function and particularly a light blocking function. It was confirmed that it was excellent in function and had sufficient contrast. Further, as shown in FIG. 6, it has been found that when the cell voltage is in the intermediate state between the above two states, the brightness can be adjusted according to the voltage, so that it can be suitably used for halftone display or illumination dimming.

Example 2 <Preparation of liquid crystal cell> The following formula:

[0056]

[Chemical 2]

A poly (hydromethylsiloxane) having a repeating unit represented by the formula below, with 75% equivalent of Si--H bonds in the poly (hydromethylsiloxane):

[0058]

[Chemical 3]

By a hydrosilylation reaction with a compound represented by the formula (1), poly (4-methoxyphenyl-4'-hexyloxybenzoate methylsiloxane) as a side chain type liquid crystalline polymer [grafting ratio G of side chain liquid crystal group G = 75%]
After synthesizing, heat treatment at 100 ° C for 24 hours to remove residual Si
The -H group was crosslinked. Next, 27.3 parts by weight of this side chain type liquid crystalline polymer and the following components were dissolved in a mixed solvent of acetone and dichloroethane (weight ratio 50:50) to obtain a coating liquid. Low-molecular liquid crystal material: 4-n-butylbenzoic acid-4'-octyloxyphenyl ester ... 27.3 parts by weight E63 (mixed liquid crystal manufactured by Merck Japan Ltd.) ... 50 parts by weight Electrolyte: tetraethylammonium bromide ... above 3 0.05 wt% with respect to the total amount of the liquid crystal of the seeds, and the above coating solution is applied on the transparent electrode layer of the glass substrate having the transparent electrode layer formed on its surface by the bar coating method, and the coating liquid is applied at room temperature for 30%. After being dried for a minute to form a mixed film, the same glass substrates were laminated so that the transparent electrode layer was in contact with the mixed film to prepare a liquid crystal cell. <Production of Liquid Crystal Element> The same procedure as in the production of the liquid crystal element of Example 1 was repeated except that the liquid crystal cell having the mixed film as the liquid crystal layer was produced in the production of the above liquid crystal cell.
A liquid crystal element having the configuration shown in (a) and (b) was produced. <Measurement of operation> The liquid crystal element is vertically irradiated with a spotlight (luminance 9500 cd / m ² ) from its light incident side (liquid crystal cell side, right side in FIGS. 1 (a) and 1 (b)) while The luminance of the element surface of the liquid crystal element was measured by a luminance meter arranged on the emission side (selective reflection member side, left side in FIGS. 1 (a) and 1 (b)), and the element surface luminance when the cell voltage was 60 V DC was 3000 cd. / M ² , cell voltage 1 kHz, 6
The brightness of the device surface when an AC wave of 0 V is 200 cd / m ² , and the contrast represented by the ratio of the brightness of both device surfaces is 3000 /
It was confirmed that 200 = 15, which has a function of transmitting / blocking light and also has an excellent light blocking function and a sufficient contrast. Further, in any of the states, even when the application of the cell voltage was stopped, there was no change in the device surface luminance, which confirms that the above device has a memory property.

Comparative Example 1 The liquid crystal cell prepared in Example 1 was measured for the element surface brightness on the light emitting side without combining it with the selective reflection member. The element surface brightness at a cell voltage of 0 V was 3800 cd / m 2.
² , the element surface brightness at a cell voltage of 100 V is 8800 cd
At / m ² , it was found that the light blocking function was particularly poor and the light transmission-blocking function was insufficient. In addition, the contrast represented by the ratio of the brightness of both device surfaces is 8800/3800 =
Since it was only 2.23, it was found that it does not have sufficient contrast and is insufficient for display or dimming.

[0061]

As described above in detail, the liquid crystal device and the liquid crystal device of the present invention are superior to the conventional light-scattering liquid crystal device particularly in the light blocking function and have a high contrast ratio. The brightness can be modulated. Further, since the liquid crystal device and the liquid crystal device of the present invention do not use a polarizer, they have excellent durability and heat resistance, and are effectively used as a display / light control device using a light source with a large amount of light and high brightness.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a liquid crystal element of the present invention, in which FIG. 1 (a) is a schematic diagram showing a light blocking state, and FIG. 1 (b) is a schematic diagram showing a light transmitting state.

2A and 2B are views for explaining the function of a selective reflection member used in the liquid crystal element, wherein FIG. 2A is a schematic view showing a light reflection state, and FIG. 2B is a schematic view showing a light transmission state. Is.

FIG. 3 is an enlarged schematic view of a modification of the selective reflection member.

4A and 4B are cross-sectional views each showing a composite film used as a liquid crystal layer in the liquid crystal element of the present invention.

5A and 5B are views showing an example of the liquid crystal device of the present invention, FIG. 5A is a schematic view showing an example in which a louver is used as a light beam adjusting member, and FIG. 5B is a collimating lens as a light beam adjusting member. It is a schematic diagram showing an example using.

FIG. 6 is a graph showing the relationship between applied voltage and device surface brightness in the liquid crystal device of Example 1.

[Explanation of symbols]

 L liquid crystal element 1 selective reflection member 20 liquid crystal layer 20a carrier film 20b liquid crystal material 30 collimator lens (light beam adjusting member) 31 louver (light beam adjusting member)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ning Saito 1-3-3 Shimaya, Konohana-ku, Osaka Sumitomo Electric Industries, Ltd. Osaka Works

Claims (5)

[Claims] 1. A plate-shaped selective reflection member that transmits light incident at an angle in the vicinity of the normal direction in the light incident direction and transmits light incident at other angles in the light emission direction in accordance with an applied voltage. A liquid crystal element, which is arranged on the light exit side of a liquid crystal layer that transmits and scatters light. 2. A structure in which a liquid crystal layer has a structure in which a liquid crystal material is filled in the continuous pores of a carrier film made of a transparent matrix having a three-dimensional network structure, or the liquid crystal material is granular in a carrier film made of a transparent matrix. 2. The liquid crystal element according to claim 1, which is a composite film having a structure dispersed in. 3. The liquid crystal device according to claim 1, wherein the liquid crystal layer is a mixed film containing a liquid crystalline polymer, a low molecular weight liquid crystal material, and a minute amount of an electrolyte. 4. The liquid crystal device according to claim 1, and a light beam adjusting device disposed on the light beam incident side of the liquid crystal device and adjusting an incident angle of a light beam incident on the liquid crystal device within a light beam reflection angle of the selective reflection member. A liquid crystal device comprising: a member. 5. The liquid crystal device according to claim 4, wherein the light beam adjusting member is a collimating lens or a louver.