JP2021105663A - Liquid crystal display - Google Patents

Abstract

To provide a liquid crystal display that has high reflectance of incident light, has high white display quality, and reduces a difference in hue due to a difference in environmental temperature.SOLUTION: A liquid crystal display 10 comprises first to third cholesteric liquid crystal layers. The first cholesteric liquid crystal layer 1 includes two or more types of optically active compounds selected such that temperature dependency of a selected reflection wavelength becomes zero and selectively reflects red light. The second cholesteric liquid crystal layer 2 includes two or more types of optically active compounds selected such that temperature dependency of a selected reflection wavelength becomes zero and selectively reflects green light. The third cholesteric liquid crystal layer 3 includes two or more types of optically active compounds selected such that temperature dependency of a selected reflection wavelength becomes zero and selectively reflects blue light. When the total thickness of the first to third cholesteric liquid crystal layers is 100%, a layer farthest from a display surface is 28 to 48%, an intermediate layer is 23 to 39%, and a layer on a display surface side is 23 to 39%.SELECTED DRAWING: Figure 1

Description

The present invention relates to a liquid crystal display device.

Conventionally, there are cholesteric (chiral nematic) liquid crystal compositions that form a spiral molecular arrangement. A liquid crystal display device using a cholesteric liquid crystal composition has bistability in which two states, a planar state that reflects incident light and a focal conic state that transmits incident light, are stably held under no electric field. .. Therefore, it is particularly preferably used for electronic books, electronic price tags, presentation panels, etc., which require low power consumption.

When the liquid crystal display device using the cholesteric liquid crystal composition is in the planar state, the spiral axis of the cholesteric liquid crystal composition is in a state perpendicular to the substrate sandwiching the cholesteric liquid crystal composition. Then, of the incident light incident on the liquid crystal display device, only the light having a circularly polarized light component that coincides with the spiral twisting direction of the cholesteric liquid crystal composition and having the same wavelength as the spiral period is reflected (selective reflection).

The wavelength (λ) that is selectively reflected is determined by the product of the average refractive index (n) of the cholesteric liquid crystal composition and the liquid crystal pitch length (P), which is the spiral period of the cholesteric liquid crystal composition. Therefore, the wavelength (λ) that is selectively reflected changes depending on the liquid crystal pitch length (P). The liquid crystal pitch length (P) can be adjusted by changing the type and concentration of the chiral dopant in the cholesteric liquid crystal composition. Therefore, the selective reflection wavelength can be adjusted by changing the type and concentration of the chiral dopant in the cholesteric liquid crystal composition.

Examples of the liquid crystal composition used in the liquid crystal display device include those described in Patent Documents 1 to 5.

Japanese Patent No. 4245173 Japanese Patent No. 4637908 JP-A-2018-95668 Japanese Unexamined Patent Publication No. 2010-275463 Japanese Unexamined Patent Publication No. 2019-123822

By using the liquid crystal composition as described above, for example, a cholesteric liquid crystal composition adjusted to a selective reflection wavelength corresponding to each of RGB is prepared, and this is injected into three separate liquid crystal panels and laminated. , A liquid crystal display device capable of color display and the like can be obtained. However, in a liquid crystal display device in which three layers of RGB are stacked, the reflectance of incident light becomes low depending on the size of the gap between each RGB cell (thickness of the cholesteric liquid crystal layer) and the order in which RGB is stacked. In addition, white with a tint other than white is displayed, which causes deterioration of the display quality of white.

Further, the selective reflection wavelength of the liquid crystal display device using the cholesteric liquid crystal composition has a temperature dependence. This is because the spiral winding strength (spiral period (chiral pitch length)) of the cholesteric liquid crystal composition changes depending on the temperature. Therefore, in a conventional liquid crystal display device using a cholesteric liquid crystal composition, when the temperature of the usage environment changes, the selective reflection wavelength changes, the displayed color changes, and as a result, the display quality of white deteriorates. There is an inconvenience that it will end up.

In addition, an optically active compound such as a chiral compound for imparting pitch to the cholesteric liquid crystal composition is as short as the visible light wavelength by adding as little as possible in order to reduce an adverse effect on the physical properties of the host liquid crystal composition. It is required that the pitch can be obtained. Therefore, a chiral compound having an extremely strong twist (strong HTP) is selected. On the other hand, since the pitch length of the cholesteric liquid crystal composition has temperature dependence as described above, if the structure of the chiral compound is not properly selected, the color tone may change due to the change in the selective reflection wavelength. The deterioration of the white display quality is noticeable.

Further, depending on the selection of the structure of the chiral compound, the physical characteristics of the host liquid crystal composition, for example, a wide operating temperature range (low melting point of the liquid crystal layer), a wide selective reflection band (high refractive index anisotropy Δn), low drive There is a problem that the voltage (high dielectric anisotropy Δε) is impaired and the display performance is significantly deteriorated.

That is, there is a demand for a cholesteric liquid crystal layer having little color change with respect to temperature changes and a cholesteric liquid crystal composition capable of realizing the same while maintaining the conventional display performance such as low drive voltage, wide selective reflection band, and wide operating temperature range. Further, when three layers of RGB are laminated, there is a demand for a liquid crystal display device that displays white without color and has a small change in color even when the temperature changes.

The present invention has been made in view of the above circumstances, and is a liquid crystal display device using a cholesteric liquid crystal composition, which has high reflectance of incident light, high white display quality, and further, environmental temperature. It is an object of the present invention to provide a liquid crystal display device in which the difference in color due to the difference between the two is small.

[1] A first cholesteric liquid crystal layer, a second cholesteric liquid crystal layer, and a third cholesteric liquid crystal layer that are laminated to each other are provided.
The first cholesteric liquid crystal layer contains a first cholesteric liquid crystal composition containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects red light. Reflected on
The second cholesteric liquid crystal layer contains a second cholesteric liquid crystal composition containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects green light. Reflected on
The third cholesteric liquid crystal layer contains a third cholesteric liquid crystal composition containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects blue light. Reflected on
When the total thickness of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer is 100%, the ratio of the thickness of the layer farthest from the display surface is 28 to 48%, which is intermediate. A liquid crystal display device in which the ratio of the thickness of the layer is 23 to 39% and the ratio of the thickness of the layer on the display surface side is 23 to 39%.

[2] Of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer, the thickness of the layer farthest from the display surface is larger than the thickness of the intermediate layer, and the thickness of the intermediate layer The liquid crystal display device according to the above [1], wherein the thickness is larger than the thickness of the layer on the display surface side.

[3] Of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer, the thickness of the intermediate layer is the thickness of the layer farthest from the display surface and the thickness of the layer on the display surface side. The liquid crystal display device according to the above [1], which is smaller than any of the above.

[4] The first cholesteric liquid crystal layer is the layer farthest from the display surface, the second cholesteric liquid crystal layer is an intermediate layer, and the third cholesteric liquid crystal layer is a layer on the display surface side. ] To [3]. The liquid crystal display device according to any one of.

[5] Of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer, the layer in which the spiral twist direction of the cholesteric liquid crystal composition forming the layer farthest from the display surface is on the display surface side. The above-mentioned [1] to [4], which is the same as the spiral twisting direction of the cholesteric liquid crystal composition constituting the above, and opposite to the spiral twisting direction of the cholesteric liquid crystal composition constituting the intermediate layer. Liquid crystal display device.

[6] The above [1], wherein at least one of the optically active compounds contained in the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition is a binaphthyl chiral compound. The liquid crystal display device according to any one of [5].

[7] The above [1] to [6], wherein at least one of the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition contains a dielectrically positive liquid crystal compound. ] The liquid crystal display device according to any one of.

[8] The above [1] to [8], wherein at least one of the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition contains a dielectrically neutral liquid crystal compound. 7] The liquid crystal display device according to any one of.

[9] The first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer are placed between two transparent substrates facing each other, the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the like. The third cholesteric liquid crystal composition is sandwiched between them.
The transparent substrate constituting one of the two adjacent cholesteric liquid crystal layers of the first, second and third cholesteric liquid crystal layers and the transparent substrate constituting the other of the two cholesteric liquid crystal layers are transparently adhered to each other. Layered,
The liquid crystal display device according to the above [1], wherein the difference in refractive index between the transparent adhesive layer and the transparent substrate in contact with the transparent adhesive layer at 25 ° C. is 0.12 or less.

[10] The first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer are placed between two transparent substrates facing each other, the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the like. The third cholesteric liquid crystal composition is sandwiched between them.
One transparent substrate constituting one of two adjacent cholesteric liquid crystal layers among the first, second, and third cholesteric liquid crystal layers, and one transparent substrate constituting the other of the two adjacent cholesteric liquid crystal layers. The liquid crystal display device according to the above [1], which is in contact with the liquid crystal display device.

[11] The first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer are placed between two transparent substrates facing each other, the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the like. The third cholesteric liquid crystal composition is sandwiched between them.
One transparent substrate constituting one of the two adjacent cholesteric liquid crystal layers of the first, second, and third cholesteric liquid crystal layers constitutes the other of the two adjacent cholesteric liquid crystal layers. The liquid crystal display device according to the above [1], which also serves as the above.

[12] The first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer are in contact with the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition, respectively. A pixel electrode substrate made of a transparent substrate provided with a pixel electrode on the side surface, and a common electrode on the surface in contact with the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition. The cholesteric liquid crystal composition is sandwiched between a common electrode substrate made of a transparent substrate provided with the above.
Two adjacent pixel electrodes of the three pixel electrodes constituting the first, second, and third cholesteric liquid crystal layers have a misalignment dx in the first direction in a plan view and are orthogonal to the first direction. The liquid crystal display device according to any one of the above [9] to [11], which is arranged so that the total (dx + dy) with the misalignment dy in the two directions is 60 μm or less.

According to the liquid crystal display device of the present invention, each of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third liquid crystal layer is selected so that the temperature dependence of the selective reflection wavelength becomes zero. It has a first cholesteric liquid crystal composition containing an optically active compound. Further, the first cholesteric liquid crystal layer selectively reflects red light, the second cholesteric liquid crystal layer selectively reflects green light, and the third cholesteric liquid crystal selectively reflects blue light. Further, when the total thickness of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer and the third cholesteric liquid crystal layer is 100%, the ratio of the thickness of the layer farthest from the display surface is 28 to 48%. The ratio of the thickness of the intermediate layer is 23 to 39%, and the ratio of the thickness of the layer on the display surface side is 23 to 39%. Therefore, it is possible to provide a liquid crystal display device having high reflectance of incident light and high white display quality. In addition, the difference in color due to the difference in the environmental temperature is small, and it is possible to prevent the white display quality from being deteriorated due to the difference in the environmental temperature.

Further, according to the liquid crystal display device of the present invention, the first cholesteric liquid crystal layer that selectively reflects red light is the layer farthest from the display surface, and the second cholesteric liquid crystal layer that selectively reflects green light. Is an intermediate layer, and a third cholesteric liquid crystal layer that selectively reflects blue light is a layer on the display surface side. Therefore, the reflectance of light having each selective reflection wavelength with respect to the incident light can be further increased, and the display quality of white can be further improved.

Further, according to the liquid crystal display device of the present invention, the spiral twisting direction of the cholesteric liquid crystal composition forming the layer farthest from the display surface is the same as the spiral twisting direction of the cholesteric liquid crystal composition forming the layer on the display surface side. Yes, and opposite to the spiral twisting direction of the cholesteric liquid crystal composition that constitutes the intermediate layer. Therefore, of the specific visible light of the incident light incident on the liquid crystal display device, the circularly polarized light component that coincides with the spiral twist direction of the cholesteric liquid crystal composition constituting the layer on the display surface side is reflected by the layer on the display surface side. Will be done. Further, among the other specific visible light of the incident light, the circularly polarized light component that coincides with the spiral twist direction of the cholesteric liquid crystal composition constituting the intermediate layer is reflected by the intermediate layer and transmitted through the layer on the display surface side. Then, it emits light from the display surface. Further, among the other specific visible light of the incident light, the circularly polarized light component that coincides with the spiral twist direction of the cholesteric liquid crystal composition constituting the layer farthest from the display surface is reflected by the layer farthest from the display surface. It passes through the intermediate layer and the layer on the display surface side and exits from the display surface. As a result, for example, as compared with the case where the spiral twist direction of the cholesteric liquid crystal composition constituting the two adjacent cholesteric liquid crystal layers of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer and the third cholesteric liquid crystal layer is the same. , It is possible to increase the reflectance of light of each selective reflection wavelength with respect to incident light.

FIG. 1 is a schematic cross-sectional view for explaining a main part of the liquid crystal display device of the first embodiment. FIG. 2A is an enlarged plan view showing only the pixel electrodes of the liquid crystal display device shown in FIG. 1, and FIG. 2B is a modified example of the arrangement of the pixel electrodes of FIG. 2A. Is. FIG. 3 is a schematic cross-sectional view for explaining a main part of the liquid crystal display device of the second embodiment. FIG. 4 is a schematic cross-sectional view for explaining a main part of the liquid crystal display device of the third embodiment.

Hereinafter, the liquid crystal display device of the present invention will be described in detail with reference to the drawings. In addition, in the drawing used in the following description, in order to make the feature of the present invention easy to understand, the feature portion may be enlarged and shown for convenience. Therefore, the dimensional ratio of each component may differ from the actual one.

<First Embodiment>
[Liquid crystal display device]
FIG. 1 is a schematic cross-sectional view for explaining a main part of the liquid crystal display device of the first embodiment.
As shown in FIG. 1, the liquid crystal display device 10 includes a first cholesteric liquid crystal layer 1, a second cholesteric liquid crystal layer 2, and a third cholesteric liquid crystal layer 3 laminated on each other. The first cholesteric liquid crystal layer 1 contains a first cholesteric liquid crystal composition containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects red light. Reflects on. The second cholesteric liquid crystal layer 2 contains a second cholesteric liquid crystal composition containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects green light. Reflects on. The third cholesteric liquid crystal layer 3 contains a third cholesteric liquid crystal composition containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects blue light. Reflects on.

In the present embodiment, the first cholesteric liquid crystal layer 1 is the layer farthest from the display surface, the second cholesteric liquid crystal layer 2 is the intermediate layer, and the third cholesteric liquid crystal layer 3 is the layer on the display surface side (display). From the surface side, B / G / R).
However, the stacking order of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 is not limited to this, and the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal are not limited to this. Layer 3 has six stacking orders based on the display surface side (from the display surface side, B / G / R, B / R / G, G / B / R, G / R / B, R / B / G, R / G / B) may be laminated.

The first cholesteric liquid crystal layer 1 is formed by sandwiching the first cholesteric liquid crystal composition 21 (hereinafter, may be referred to as “first liquid crystal composition”) between two transparent substrates 31a and 31b facing each other. Of the two transparent substrates 31a and 31b, the transparent substrate 31a arranged on the upper side in FIG. 1 is a common electrode substrate provided with a common electrode 41a on the surface on the side in contact with the first liquid crystal composition 21. Further, of the two transparent substrates 31a and 31b, the transparent substrate 31b arranged on the lower side in FIG. 1 is a pixel electrode provided with a plurality of pixel electrodes 41b on the surface on the side in contact with the first liquid crystal composition 21. It is a substrate. The common electrode 41a and the plurality of pixel electrodes 41b are connected to an R (red) pulse power supply (not shown).
An alignment film (not shown) is provided on the first liquid crystal composition 21 side of the pixel electrode 41b. An alignment film may be provided on the first liquid crystal composition 21 side of the common electrode 41a, or an alignment film may be provided on the first liquid crystal composition 21 side of the transparent substrate 31b.

The second cholesteric liquid crystal layer 2 is formed by sandwiching the second cholesteric liquid crystal composition 22 (hereinafter, may be referred to as “second liquid crystal composition”) between two transparent substrates 32a and 32b facing each other. Of the two transparent substrates 32a and 32b, the transparent substrate 32a arranged on the upper side in FIG. 1 is a common electrode substrate provided with a common electrode 42a on the surface on the side in contact with the second liquid crystal composition 22. Further, of the two transparent substrates 32a and 32b, the transparent substrate 32b arranged on the lower side in FIG. 1 is a pixel electrode provided with a plurality of pixel electrodes 42b on the surface on the side in contact with the second liquid crystal composition 22. It is a substrate. The common electrode 42a and the plurality of pixel electrodes 42b are connected to a G (green) pulse power supply (not shown).
An alignment film (not shown) is provided on the second liquid crystal composition 22 side of the pixel electrode 42b. An alignment film may be provided on the second liquid crystal composition 22 side of the common electrode 42a, or an alignment film may be provided on the second liquid crystal composition 22 side of the transparent substrate 32b.

The third cholesteric liquid crystal layer 3 is formed by sandwiching the third cholesteric liquid crystal composition 23 (hereinafter, may be referred to as “third liquid crystal composition”) between two transparent substrates 33a and 33b facing each other. Of the two transparent substrates 33a and 33b, the transparent substrate 33a arranged on the upper side in FIG. 1 is a common electrode substrate provided with a common electrode 43a on the surface on the side in contact with the third liquid crystal composition 23. Further, of the two transparent substrates 33a and 33b, the transparent substrate 33b arranged on the lower side in FIG. 1 is a pixel electrode provided with a plurality of pixel electrodes 43b on the surface on the side in contact with the third liquid crystal composition 23. It is a substrate. The common electrode 43a and the plurality of pixel electrodes 43b are connected to a pulse power supply for B (blue) (not shown).
An alignment film (not shown) is provided on the third liquid crystal composition 23 side of the pixel electrode 43b. An alignment film may be provided on the third liquid crystal composition 23 side of the common electrode 43a, or an alignment film may be provided on the third liquid crystal composition 23 side of the transparent substrate 33b.

When the total thickness of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 is 100%, the ratio of the thickness of the layer farthest from the display surface is 28 to 48%, which is intermediate. The ratio of the thickness of the layer is 23 to 39%, and the ratio of the thickness of the layer on the display surface side is 23 to 39%. In the present embodiment, when the total thickness of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 is 100%, the thickness of the first cholesteric liquid crystal layer 1 farthest from the display surface The ratio is 28 to 48%, the ratio of the thickness of the second cholesteric liquid crystal layer 2 in the middle is 23 to 39%, and the ratio of the thickness of the third cholesteric liquid crystal layer 3 on the display surface side is 23 to 39%. ..
The thickness ratio of the first cholesteric liquid crystal layer 1 farthest from the display surface is 32 to 42%, the thickness ratio of the second cholesteric liquid crystal layer 2 in the middle is 23 to 36%, and the thickness of the layer on the display surface side. The ratio is preferably 25 to 39%, the ratio of the thickness of the layer farthest from the display surface is 35 to 42%, the ratio of the thickness of the intermediate layer is 23 to 34, and the third cholesteric liquid crystal layer on the display surface side. More preferably, the ratio of the thickness of 3 is 27 to 39%.

Of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3, the thickness of the layer farthest from the display surface is larger than the thickness of the intermediate layer, and the thickness of the intermediate layer is large. It may be larger than the thickness of the layer on the display surface side. For example, it is preferable that the thickness of the first cholesteric liquid crystal layer 1 is larger than the thickness of the second cholesteric liquid crystal layer 2 and the thickness of the second cholesteric liquid crystal layer 2 is larger than the thickness of the third cholesteric liquid crystal layer 3. As a result, the reflectance of the incident light incident from the display surface side becomes higher, and white with no tint can be obtained, and as a result, the display quality of white becomes higher.

Further, among the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3, the thickness of the intermediate layer is either the thickness of the layer farthest from the display surface or the thickness of the layer on the display surface side. May be smaller than. For example, when the second cholesteric liquid crystal layer 2 is a green reflective layer having the highest human visibility, the thickness of the second cholesteric liquid crystal layer 2 is the thickness of the first cholesteric liquid crystal layer 1 and the thickness of the third cholesteric liquid crystal layer 3. When it is smaller than any of the thicknesses, it is possible to obtain white without color, and as a result, the display quality of white is higher.

The thickness of the first cholesteric liquid crystal layer 1 is, for example, 2.7 μm to 8.0 μm, the thickness of the second cholesteric liquid crystal layer 2 is, for example, 2.7 μm to 8.0 μm, and the third cholesteric liquid crystal layer 3 is For example, it is 2.7 μm to 8.0 μm. As in the present embodiment, the first cholesteric liquid crystal layer 1 is the layer farthest from the display surface, the second cholesteric liquid crystal layer 2 is the intermediate layer, and the third cholesteric liquid crystal layer 3 is the layer on the display surface side. In this case, the thickness of the first cholesteric liquid crystal layer 1 is preferably 3.3 μm to 8.0 μm, the thickness of the second cholesteric liquid crystal layer 2 is preferably 2.7 μm to 6.3 μm, and the third The cholesteric liquid crystal layer 3 is preferably 2.7 μm to 6.3 μm. If the thickness of each liquid crystal layer is too thin, the brightness of the reflected light becomes small and the display becomes dark, and if it is too thick, the brightness is good, but the driving voltage becomes too high, which makes it difficult to drive. Therefore, the above range is preferable because the brightness and the driving voltage are in a good range.

As the transparent substrates 31a, 31b, 32a, 32b, 33a, 33b of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3, conventionally known ones can be used. For example, as the transparent substrates 31a, 31b, 32a, 32b, 33a, 33b, a transparent sheet made of a resin film such as polyethylene terephthalate, glass, or the like can be used.

The common electrodes 41a, 42a, and 43a provided in the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3, respectively, include metals such as silver, copper, and aluminum, and indium tin oxide (ITO). , Indium tin oxide (IZO), metal oxides such as indium oxide, and other conventionally known materials can be used.
The pixel electrodes 41b, 42b, and 43b provided in the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3, respectively, include metals such as silver, copper, and aluminum, and indium tin oxide (ITO). , Indium tin oxide (IZO), metal oxides such as indium oxide, and other conventionally known materials can be used.

As the alignment film provided on each of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3, a conventionally known one formed of a polyimide film or the like can be used. The alignment film may be a homogeneous alignment film or a homeotropic alignment film.
Further, a homogeneous alignment film and a homeotropic alignment film may be used in combination. Specifically, in the liquid crystal display device 10 of the present embodiment, for example, the homeo is placed on the common electrode 41a of the first cholesteric liquid crystal layer 1. A tropic alignment film may be provided, and a homogenius alignment film may be provided on the transparent substrate 31b and the pixel electrode 41b. Further, a homeotropic alignment film may be provided on the common electrode 42a of the second cholesteric liquid crystal layer 2, and a homogeneous alignment film may be provided on the transparent substrate 32b and the pixel electrode 42b. Similarly, a homeotropic alignment film may be provided on the common electrode 43a of the third cholesteric liquid crystal layer 3, and a homogenius alignment film may be provided on the transparent substrate 33b and the pixel electrode 43b.

As shown in FIG. 2A, in a plan view of the liquid crystal display device 10, the pixel electrode 41b of the first cholesteric liquid crystal layer 1, the pixel electrode 42b of the second cholesteric liquid crystal layer 2, and the pixel electrode of the third cholesteric liquid crystal layer 3 43b has a quadrangular shape.
For example, when the screen size is 8 inches diagonally and the resolution is 162 ppi, the lengths of the pixel electrodes 41b and 42 are preferably 122 μm to 147 μm and the width is preferably 122 μm to 147 μm, and the pixel electrodes 41b and 42 are square. The length of one side is preferably 122 μm to 147 μm.
Further, for example, when the screen size is 12 inches diagonally and the resolution is 106 ppi, the lengths of the pixel electrodes 41b and 42 are preferably 205 μm to 225 μm and the width is preferably 205 μm to 225 μm, and the pixel electrodes 41b and 42 are square. In some cases, the length of one side is preferably 205 μm to 225 μm.
Further, for example, when the screen size is diagonally 4 inches and the resolution is 318 ppi, the lengths of the pixel electrodes 41b and 42 are preferably 70 μm to 90 μm and the width is preferably 70 μm to 90 μm, and the pixel electrodes 41b and 42 are square. In some cases, the length of one side is preferably 70 μm to 90 μm.

Two adjacent pixel electrodes of the pixel electrode 41b of the first cholesteric liquid crystal layer 1, the pixel electrode 42b of the second cholesteric liquid crystal layer 2 and the pixel electrode 43b of the third cholesteric liquid crystal layer 3 are oriented in the first direction in a plan view. It is preferable that the total (dx + dy) of the misalignment dx and the misalignment dy in the second direction orthogonal to the first direction is 60 μm or less. In the present embodiment, the pixel electrode 41b and the pixel electrode 42b are the sum of the misalignment dx in the X direction (first direction) and the misalignment dy in the Y direction (second direction) orthogonal to the X direction in a plan view. It is preferable that (dx + dy) is arranged so as to be 60 μm or less, more preferably 50 μm or less, further preferably 45 μm or less, further particularly preferably 30 μm or less, and the total (dx + dy) is The smaller the value, the better. Similarly, the pixel electrodes 42b and the pixel electrodes 43b are preferably arranged so that the total of the misalignments (dx + dy) is 60 μm or less, more preferably 50 μm or less, and further preferably 45 μm or less. It is preferably 30 μm or less, and the smaller the total (dx + dy), the more preferable. When the total of the above misalignments (dx + dy) is 60 μm or less, all of the pixel electrodes 41b, 42b, 43b with respect to the area of the region where all of the pixel electrodes 41b, 42b, 43b overlap (total superposition region). The area of the non-overlapping region (non-overlapping region) can be made extremely small. As a result, when white is displayed in the entire superimposition region, blue, green, red, or a mixed color of two of these is added to the outer edge of the white tint in the total superimposition region in the non-superimposition region. It is possible to prevent or suppress the display, and it is possible to further improve the display quality of white.

Further, as shown in FIG. 2B, the pixel electrode 41b, the pixel electrode 42b, and the pixel electrode 43b have the maximum value dx _max of the positional deviation in the X direction (first direction) in a plan view and are orthogonal to the X direction. It is preferably arranged so that the total (dx _max + dy _{max ) with the maximum value dy max of the} misalignment in the Y direction (second direction) is 60 μm or less, preferably 50 μm or less, and 45 μm or less. It is preferably 30 μm or less, and more preferably 30 μm or less. Thereby, the display quality of white can be further improved. Further, the liquid crystal display device 10 can suppress the deterioration of visibility due to the above-mentioned misalignment and can display with good visibility.

In the present embodiment, the transparent substrate 31a (pixel electrode substrate) arranged on the second cholesteric liquid crystal layer 2 side (upper side in FIG. 1) of the first cholesteric liquid crystal layer 1 and the first cholesteric of the second cholesteric liquid crystal layer 2 The transparent adhesive layer 5 is provided in contact with the transparent substrate 32b (common electrode substrate) arranged on the liquid crystal layer 1 side. Further, a transparent substrate 32a (pixel electrode substrate) arranged on the third cholesteric liquid crystal layer 3 side of the second cholesteric liquid crystal layer 2 and a transparent substrate arranged on the second cholesteric liquid crystal layer 2 side of the third cholesteric liquid crystal layer 3. A transparent adhesive layer 6 is provided in contact with 33b (common electrode substrate).

Examples of the transparent adhesive layer 5 and the transparent adhesive layer 6 include a cured product of a pressure-sensitive adhesive containing a transparent resin (OCR (Optical Clear Resin)) such as a silicone elastomer, an epoxy resin, and a urethane resin, and silicone elastomers on both sides of the transparent resin film. A transparent sheet-like material provided with a transparent adhesive (OCA (Optical Clear Adhesive)) layer such as the above can be used.

The transparent adhesive layer 5 preferably has a refractive index difference of 0.12 or less, preferably 0.10 or less, from the transparent substrates 31a and 32b in contact with the transparent adhesive layer 5 at 25 ° C. More preferred. Further, the transparent adhesive layer 6 preferably has a refractive index difference of 0.12 or less, preferably 0.10 or less, from the transparent substrates 32a and 33b in contact with the transparent adhesive layer 6 at 25 ° C. Is more preferable. When the above difference in refractive index is 0.12 or less, the light transmitted through the second cholesteric liquid crystal layer 2 and incident on the first cholesteric liquid crystal layer 1 via the transparent adhesive layer 5 and the first liquid crystal composition 21. Light that is reflected by the transparent adhesive layer 5 and enters the second cholesteric liquid crystal layer 2 through the transparent adhesive layer 5 is likely to enter and exit the transparent adhesive layer 5. Further, the light transmitted through the third cholesteric liquid crystal layer 3 and incident on the second cholesteric liquid crystal layer 2 via the transparent adhesive layer 6 and reflected by the second liquid crystal composition 22 is reflected through the transparent adhesive layer 6 to the second. 3 Light incident on the cholesteric liquid crystal layer 3 is likely to be incident on and emitted from the transparent adhesive layer 6. As a result, the proportion of the light incident on the liquid crystal display device 10 that cannot be taken out from the liquid crystal display device 10 by transmitting the transparent adhesive layer 5 and / or the transparent adhesive layer 6 is reduced, and the reflected light is further reflected. The rate will be high.

On the other hand, for example, the transparent substrate 31a, which is not provided with the transparent adhesive layer 5 and is arranged on the second cholesteric liquid crystal layer 2 side of the first cholesteric liquid crystal layer 1, and the first cholesteric of the second cholesteric liquid crystal layer 2. When the transparent substrate 32b arranged on the liquid crystal layer 1 side is arranged in contact with each other, the transparent substrate 31a and a part of the transparent substrate 32b do not adhere to each other, and a gap is formed between the transparent substrate 31a and the transparent substrate 32b. May be done. Similarly, the transparent substrate 32a, which is not provided with the transparent adhesive layer 6 and is arranged on the third cholesteric liquid crystal layer 3 side of the second cholesteric liquid crystal layer 2, and the second cholesteric liquid crystal layer 2 of the third cholesteric liquid crystal layer 3 When the transparent substrate 33b arranged on the side is arranged in contact with each other, the transparent substrate 32a and a part of the transparent substrate 33b do not come into close contact with each other, and a gap is formed between the transparent substrate 32a and the transparent substrate 33b. There is. In these gaps, air (refractive index at 25 ° C. of about 1.0), which is a substance having a large difference in refractive index from the transparent substrates 31a, 32b, 32a, and 33b, is present. Therefore, the light that can be extracted from the liquid crystal display device 10 is reduced due to refraction at the interface between the transparent substrates 31a and 32b and the gap (air) or the interface between the transparent substrates 32a and 33b and the gap (air), and the liquid crystal display device 10 There is a risk of reducing the reflectance.

In the liquid crystal display device 10 shown in FIG. 1, a light absorption layer 7 is arranged on the opposite side of the first cholesteric liquid crystal layer 1 from the second cholesteric liquid crystal layer 2. The light absorption layer 7 absorbs the light transmitted through the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3. Since the light absorption layer 7 is provided, the light transmitted through the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 is absorbed, so that better visibility can be obtained. The light absorption layer 7 can be formed by a conventionally known method using a conventionally known material.

The cholesteric liquid crystal composition having the relatively longest wavelength (for example, red) selective reflection and the cholesteric liquid crystal composition having the relatively shortest wavelength (for example, blue) selective reflection have the same spiral twist direction. In the cholesteric liquid crystal composition having selective reflection of the wavelength between them, the spiral twist direction is preferably opposite. The "spiral twist direction" is the axis of the spiral axis in the direction perpendicular to the display surface of the liquid crystal display device 10. When viewed from the display surface side, clockwise means "left-handed twist" and counterclockwise means "right-handed twist".

For example, when the layers are laminated in the order of reflecting blue, green, and red light from the display surface, the spiral twist direction of the cholesteric liquid crystal composition forming the layer farthest from the display surface is the cholesteric liquid crystal composition forming the layer on the display surface side. It is preferable that the direction is the same as the spiral twist direction of the object and is opposite to the spiral twist direction of the cholesteric liquid crystal composition constituting the intermediate layer. For example, in the present embodiment, the spiral twisting direction of the first liquid crystal composition 21 constituting the first cholesteric liquid crystal layer 1 is the same as the spiral twisting direction of the third liquid crystal composition 23 constituting the third cholesteric liquid crystal layer 3. It is preferable that the direction is opposite to the spiral twist direction of the second liquid crystal composition 22 constituting the second cholesteric liquid crystal layer 2.

In this case, among the blue light of the incident light incident on the liquid crystal display device 10, the circularly polarized light component that coincides with the spiral twisting direction of the third liquid crystal composition 23 constituting the third cholesteric liquid crystal layer 3 is the third cholesteric liquid crystal layer. Reflected by 3. Further, among the green light of the incident light, the circularly polarized light component that coincides with the spiral twisting direction of the second liquid crystal composition 22 constituting the second cholesteric liquid crystal layer 2 is reflected by the second cholesteric liquid crystal layer 2 and is reflected by the third cholesteric liquid crystal layer 2. It passes through the liquid crystal layer 3 and exits from the display surface. Further, among the red light of the incident light, the circularly polarized light component that coincides with the spiral twisting direction of the first liquid crystal composition 21 constituting the first cholesteric liquid crystal layer 1 is reflected by the first cholesteric liquid crystal layer 1 and is reflected by the second cholesteric liquid crystal layer 1. It passes through the liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 and exits from the display surface. As a result, the reflectance of light having each selective reflection wavelength with respect to the incident light can be increased, and color mixing can be suppressed.

The spiral twisting direction of the first liquid crystal composition 21 of the first cholesteric liquid crystal layer 1, the spiral twisting direction of the second liquid crystal composition 22 of the second cholesteric liquid crystal layer 2, and the third liquid crystal composition 23 of the third cholesteric liquid crystal layer 3. The spiral twisting direction of the above is determined by the type of the optically active compound contained in the first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23, respectively.

In the liquid crystal display device 10 of the present embodiment, the first liquid crystal composition 21 contained in the first cholesteric liquid crystal layer 1, the second liquid crystal composition 22 contained in the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3 The third liquid crystal composition 23 contained contains two or more kinds of optically active compounds selected so that the temperature dependence (wavelength change) of the selective reflection wavelength due to the temperature dependence of the liquid crystal pitch length (chiral pitch length) becomes zero. contains. Therefore, in the liquid crystal display device 10 of the present embodiment, the difference in color due to the difference in the environmental temperature is small.

In the liquid crystal display device 10 of the present embodiment, the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3 are each selected so that the temperature dependence of the selective reflection wavelength becomes zero. By including the first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23 containing more than one kind of optically active compound, the temperature dependence of the selective reflection wavelength in the temperature range of 0 to 50 ° C. Is preferably 0.3 nm / ° C. or lower, more preferably 0.25 nm / ° C. or lower, further preferably 0.2 nm / ° C. or lower, and the smaller the better. Here, the temperature dependence of the selective reflection wavelength in the temperature range of 0 to 50 ° C. is the difference between the maximum value and the minimum value of the wavelength of the selective reflection light in the temperature range of 0 to 50 ° C. divided by the temperature range. Means a value.

In the liquid crystal display device 10 of the present embodiment, the difference between the temperature dependence of the selective reflection wavelength in the first cholesteric liquid crystal layer 1 and the temperature dependence of the selective reflection wavelength in the second cholesteric liquid crystal layer 2 is 0. It is preferably .15 nm / ° C. or lower, more preferably 0.125 nm / ° C. or lower, further preferably 0.1 nm / ° C. or lower, and the smaller the better. If the difference in temperature dependence of the selective reflection wavelength between the first cholesteric liquid crystal layer 1 and the second cholesteric liquid crystal layer 2 is small, the first cholesteric liquid crystal layer 1 and the second cholesteric liquid crystal layer 2 are supported regardless of the environmental temperature. Expresses selective reflected light. Therefore, regardless of the environmental temperature, white reflected light having high reflectance of incident light and no color can be obtained.
Further, the difference between the temperature dependence of the selective reflection wavelength in the second cholesteric liquid crystal layer 2 and the temperature dependence of the selective reflection wavelength in the third cholesteric liquid crystal layer 3 is 0.15 nm / ° C. or less. Is more preferable, 0.125 nm / ° C. or lower is more preferable, and 0.1 nm / ° C. or lower is more preferable, and the smaller the better. If the difference in temperature dependence of the selective reflection wavelength between the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 is small, it corresponds to each layer of the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 regardless of the environmental temperature. Expresses selective reflected light. Therefore, regardless of the environmental temperature, white reflected light having high reflectance of incident light and no color can be obtained.

In the liquid crystal display device 10 of the present embodiment, for example, the surface on the first cholesteric liquid crystal layer 1 side is used as the display surface, the first cholesteric liquid crystal layer 1 is in a planar state, the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal. Red is displayed when layer 3 is in the focal conic state. Further, when the second cholesteric liquid crystal layer 2 is in the planar state, the first cholesteric liquid crystal layer 1 and the third cholesteric liquid crystal layer 3 are in the focal conic state, green is displayed, and the third cholesteric liquid crystal layer 3 is in the planar state. ) State, blue is displayed when the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 are in the focal conic state. In the liquid crystal display device 10 shown in FIG. 1, the two states of the planar state and the focal conic state of each of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3 are stabilized under no electric field. Can be held. Therefore, the liquid crystal display device 10 of the present embodiment has a memory property.

In the liquid crystal display device 10 of the present embodiment, switching between the planar state and the focal conic state in the first cholesteric liquid crystal layer 1 can be switched depending on the magnitude and shape of the voltage applied between the common electrode 41a and the pixel electrode 41b. Similarly, switching between the planar state and the focal conic state in the second cholesteric liquid crystal layer 2 and switching between the planar state and the focal conic state in the third cholesteric liquid crystal layer 3 can be switched depending on the magnitude and shape of the applied voltage. These applied voltages are controlled by a drive circuit (not shown).

In the present embodiment, the planar state and the focal conic state of the first cholesteric liquid crystal layer 1 are switched, the planar state and the focal conic state of the second cholesteric liquid crystal layer 2 are switched, and the planar state of the third cholesteric liquid crystal layer 3 is switched. And switching to the focal conic state at the same time. Controlling the planar state or focal conic state of the first cholesteric liquid crystal layer 1, the planar state or focal conic state of the second cholesteric liquid crystal layer 2, and the planar state or focal conic state (8 patterns) of the third cholesteric liquid crystal layer 3. Then, blue, green, red, cyan, magenta, yellow, white, black, etc. are displayed. Therefore, a full-color display can be obtained without providing a color filter.

Next, optics when any or all of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 of the liquid crystal display device 10 are in the planar state and when they are in the focal conic state. The characteristics will be described in detail.

In FIG. 1, for example, when the first cholesteric liquid crystal layer 1 is in the planar state, the spiral axis of the first cholesteric liquid crystal layer 1 in the first liquid crystal composition 21 is in a state substantially perpendicular to the transparent substrates 31a and 31b. There is.

In this case, when the incident light L0 is incident on the liquid crystal display device 10 from the third cholesteric liquid crystal layer 3 side, the incident light L0 is transmitted through the third cholesteric liquid crystal layer 3 and the second cholesteric liquid crystal layer 2, and one of the incident light L0. The red light L1 (indicated by the arrow L1 in FIG. 1) is selectively reflected (selectively reflected) by the first liquid crystal composition 21 of the first cholesteric liquid crystal layer 1. The red light L1 selectively reflected by the first liquid crystal composition 21 is a circularly polarized light component that coincides with the spiral twist direction of the first liquid crystal composition 21. The red light L1 reflected by the first liquid crystal composition 21 passes through the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 and is emitted from the liquid crystal display device 10. As a result, red is displayed on the liquid crystal display device 10.

Further, of the incident light L0 incident on the liquid crystal display device 10, the light that is not reflected by the first liquid crystal composition 21 passes through the first cholesteric liquid crystal layer 1 and is absorbed by the light absorption layer 7. The light transmitted through the first cholesteric liquid crystal layer 1 is light having the same wavelength as the red light L1 selectively reflected by the first liquid crystal composition 21, but having a wavelength different from that of the red light L1 and the light in the opposite spiral twist direction. ..

In FIG. 1, when the second cholesteric liquid crystal layer 2 is in the planar state and the first cholesteric liquid crystal layer 1 and the third cholesteric liquid crystal layer 3 are in the focal conic state, the second liquid crystal composition 22 of the second cholesteric liquid crystal layer 2 The spiral shaft is substantially perpendicular to the transparent substrates 32a and 32b.
In this case, the incident light L0 passes through the third cholesteric liquid crystal layer 3, and a part of the incident light L0, the green light L2 (arrow L2 in FIG. 1), is the second liquid crystal composition 22 of the second cholesteric liquid crystal layer 2. Is selectively reflected (selective reflection). The green light L2 selectively reflected by the second liquid crystal composition 22 is a circularly polarized light component that coincides with the spiral twist direction of the second liquid crystal composition 22. The green light L2 reflected by the second liquid crystal composition 22 passes through the third cholesteric liquid crystal layer 3 and is emitted from the liquid crystal display device 10. As a result, green is displayed on the liquid crystal display device 10.

Of the incident light L0 incident on the liquid crystal display device 10, the light not reflected by the second liquid crystal composition 22 passes through the second cholesteric liquid crystal layer 2. The light transmitted through the second cholesteric liquid crystal layer 2 has the same wavelength as the green light L2 selectively reflected by the second liquid crystal composition 22, but has a wavelength different from that of the green light L1 and the light in the opposite spiral twist direction. .. The light that is not reflected by the second liquid crystal composition 22 passes through the second cholesteric liquid crystal layer 2 and the first cholesteric liquid crystal layer 1 and is absorbed by the light absorption layer 7.

In FIG. 1, when the third cholesteric liquid crystal layer 3 is in the planar state and the first cholesteric liquid crystal layer 1 and the second cholesteric liquid crystal layer 2 are in the focal conic state, the third liquid crystal composition 23 of the third cholesteric liquid crystal layer 3 The spiral shaft is substantially perpendicular to the transparent substrates 33a and 33b.
In this case, a part of the incident light L0, the blue light L3 (arrow L3 in FIG. 1), is selectively reflected (selectively reflected) by the third liquid crystal composition 23 of the third cholesteric liquid crystal layer 3. The blue light L3 selectively reflected by the third liquid crystal composition 23 is a circularly polarized light component that coincides with the spiral twist direction of the third liquid crystal composition 23. The blue light L3 reflected by the third liquid crystal composition 23 is emitted from the liquid crystal display device 10. As a result, blue is displayed on the liquid crystal display device 10.

Of the incident light L0 incident on the liquid crystal display device 10, the light that is not reflected by the third liquid crystal composition 23 passes through the third cholesteric liquid crystal layer 3. The light transmitted through the third cholesteric liquid crystal layer 3 is a light having the same wavelength as the blue light L3 selectively reflected by the third liquid crystal composition 23 but having the opposite spiral twisting direction and a light having a wavelength different from that of the blue light L3. be. The light having the same wavelength as the blue light L3 selectively reflected by the third liquid crystal composition 23 but having the opposite spiral twist direction, and the light having a wavelength different from that of the blue light L3 are the third cholesteric liquid crystal layer 3 and the second cholesteric. It passes through the liquid crystal layer 2 and the first cholesteric liquid crystal layer 1 and is absorbed by the light absorption layer 7.

Further, when all of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third focal conic liquid crystal layer 3 are in the planar state, the incident light L0 from the third cholesteric liquid crystal layer 3 side to the liquid crystal display device 10. Is incident, (1) a part of the red light L1 of the incident light L0 is selectively reflected by the first liquid crystal composition 21 of the first cholesteric liquid crystal layer 1, and (2) a part of the incident light L0. The green light L2 is selectively reflected by the second liquid crystal composition 22 of the second cholesteric liquid crystal layer 2, and (3) a part of the blue light L3 of the incident light L0 is the third cholesteric liquid crystal layer 3. 3 It is selectively reflected by the liquid crystal composition 23. As a result, white, which is a composite color of red, green, and blue, is displayed on the liquid crystal display device 10.

On the other hand, when all of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2 and the third focal conic liquid crystal layer 3 are in the focal conic state, the first liquid crystal composition 21 and the second cholesteric of the first cholesteric liquid crystal layer 1 The spiral axis of the second liquid crystal composition 22 of the liquid crystal layer 2 and the third liquid crystal composition 23 of the third cholesteric liquid crystal layer 3 is in a substantially horizontal state with the transparent substrates 31a, 31b, 32a, 32b, 33a, 33b. There is.

In this case, when the incident light L0 is incident on the liquid crystal display device 10 from the first cholesteric liquid crystal layer 1 side, most of the incident light L0 is the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal. It passes through the layer 3 and is absorbed by the light absorption layer 7. As a result, black is displayed on the liquid crystal display device 10.

In this way, the cholesteric liquid crystal layers that reflect light of different main wavelengths in the planar state are laminated in three layers, and the laminated first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2, and the third cholesteric liquid crystal layer 3 are laminated. By applying a voltage that changes from the planar state to the focal conic state to one or more, the orientation state of one or more liquid crystal molecules of the first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23. Is changed, and the incident light L0 is reflected or absorbed, so that a predetermined color is displayed on the liquid crystal display device 10.

[Liquid crystal composition]
Next, the compositions of the first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23 in the liquid crystal display device 10 of the present embodiment will be described in detail.
The first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23 include an optically active compound as a chiral dopant and a liquid crystal compound other than the optically active compound. In the present embodiment, the following can be used as the optically active compound and the liquid crystal compound other than the optically active compound.

The physical property value of the liquid crystal composition before the addition of the optically active compound, that is, the refractive index anisotropy Δn of the host liquid crystal composition is preferably 0.10 to 0.40, preferably 0.15 to 0.35. Is more preferable, and 0.20 to 0.30 is particularly preferable. By setting the refractive index anisotropy Δn in the above range, a wide selective reflection band can be obtained. The dielectric anisotropy Δε is preferably 10 to 50, more preferably 15 to 45, and particularly preferably 20 to 40. By setting the dielectric anisotropy Δε in the above range, low voltage drive can be realized.

Further, as the physical property value of the liquid crystal composition, the melting point, that is, the temperature for restoring the cholesteric phase from the solid phase or the like is preferably −25 ° C. or lower, more preferably −30 ° C. or lower, and −35 ° C. or lower. Is particularly preferable, and the lower the value, the more preferable. By setting the melting point in the above range, a wide operating temperature range can be obtained. Moreover, isotropic liquid phase to vary the phase transition temperature _{(T NI)} of a cholesteric phase is preferably from 60 to 120 ° C., more preferably from 70 to 110 ° C., in the range of 80 to 110 ° C. Especially preferable. By setting the phase transition temperature ( _TNI ) in the above range, a wide operating temperature range can be obtained. The smaller the viscosity η indicating the flow viscosity, the more preferable, and the lower limit thereof is not particularly limited, but if it is 100 mPa · s or less, a practically sufficient response speed can be achieved.

(Liquid crystal compounds other than optically active compounds)
As the liquid crystal compound other than the optically active compound, only one kind of compound showing a liquid crystal phase alone may be used, or a compound showing a liquid crystal phase by using a mixture of two or more kinds may be used. When two or more kinds of compounds are mixed and used as the liquid crystal compound, various combinations are possible.

The liquid crystal compound preferably contains a dielectrically positive liquid crystal compound, and preferably contains a dielectrically neutral liquid crystal compound together with the dielectrically positive liquid crystal compound. Only one kind of each of the dielectrically positive liquid crystal compound and the dielectrically neutral liquid crystal compound may be used, or two or more kinds may be used.

(Dielectrically positive liquid crystal compound)
Examples of the dielectrically positive liquid crystal compound include compounds represented by the general formula (A) and the general formula (B). The compounds represented by the general formula (A) and the general formula (B) correspond to a compound having a dielectric anisotropy Δε larger than 2 and being dielectrically positive. The compounds represented by the general formula (A) and the general formula (B) may be used alone or in combination.

The compounds represented by the general formula (A) and the general formula (B) may be used alone or in combination of two or more. The compounds represented by the general formula (A) and the general formula (B) can be appropriately selected according to the characteristics required for the liquid crystal display device 10, and a plurality of types can be used in combination as necessary. It is preferable to use 1 to 12 kinds of compounds represented by the general formula (A) and the general formula (B).

（式（Ａ）および（Ｂ）中、Ｒ^２Ａ１及びＲ^２Ｂ１は、相互に独立して、炭素原子数１から７のアルキル基、炭素原子数１から７のアルコキシ基、炭素原子数２から７のアルケニル基又は炭素原子数２から７のアルケニルオキシ基である。Ｒ^２Ａ１及びＲ^２Ｂ１上の１個又は２個以上の水素原子は、相互に独立して、フッ素原子又は塩素原子で置換されていてもよい。Ｃ^２Ａ１及びＣ^２Ｂ１は、相互に独立して、（ａ）１，４−シクロヘキシレン基（この基中に存在する１個の−ＣＨ_２−又は隣接していない２個以上の−ＣＨ_２−は−Ｏ−に置き換えられてもよい。）（ｂ）１，４−フェニレン基（この基中に存在する１個の−ＣＨ＝又は隣接していない２個以上の−ＣＨ＝は−Ｎ＝に置き換えられてもよい。）（ｃ）ナフタレン−２，６−ジイル基、１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基、デカヒドロナフタレン−２，６−ジイル基又はインダン−２，５−ジイル基（ナフタレン−２，６−ジイル基又は１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基中に存在する１個の−ＣＨ＝又は隣接していない２個以上の−ＣＨ＝は−Ｎ＝に置き換えられても良い。）及び（ｄ）１，４−シクロヘキセニレン基からなる群より選ばれる基を表し、上記の基（ａ）、基（ｂ）、基（ｃ）及び基（ｄ）は、相互に独立してシアノ基、フッ素原子又は塩素原子で置換されていても良い。Ｌ^２Ａ１及びＬ^２Ｂ１は、相互に独立して、単結合、−Ｃ_２Ｈ_４−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＦ_２Ｏ−又は−ＯＣＦ_２−を表す。Ｘ^２Ａ１及びＸ^２Ｂ１は、相互に独立して、−Ｆ、−Ｃｌ、−ＣＮ、−ＮＣＳ、−ＣＦ_３、−ＯＣＦ_３、少なくとも１つの水素原子がハロゲン原子で置換された炭素原子数1〜６のアルキル基又は少なくとも１つの水素原子がハロゲン原子で置換された炭素原子数1〜６のアルコキシ基を表す。Ｙ^２Ａ１、Ｙ^２Ａ２、Ｙ^２Ｂ１及びＹ^２Ｂ２は、相互に独立して、水素原子又はフッ素原子を表す。ｂ^２Ａ１及びｂ^２Ｂ１は、相互に独立して、１、２、３又は４を表す。）

(In formulas (A) and (B), R ^2A1 and R ^2B1 are independent of each other, an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, and 2 to 7 carbon atoms. An alkoxy group or an alkoxyoxy group having 2 to 7 carbon atoms. ^{One or more hydrogen atoms on R 2A1} and R ^2B1 are independently substituted with a fluorine atom or a chlorine atom. ^{C 2A1} and C ^2B1 may be independent of each other (a) a 1,4-cyclohexylene group (one −CH ₂₋ present in this group or two or more non-adjacent groups). -CH _2- may be replaced with -O-.) (B) 1,4-phenylene group (one -CH = existing in this group or two or more non-adjacent -CH = May be replaced with -N =.) (C) Naphthalene-2,6-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, decahydronaphthalene-2,6- One -CH = or adjacent to a diyl group or an indan-2,5-diyl group (naphthalen-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group) Two or more -CH = which are not used may be replaced with -N =) and (d) represent a group selected from the group consisting of 1,4-cyclohexenylene groups, and the above group (a). , Group (b), group (c) and group (d) may be substituted independently of each other with a cyano group, a fluorine atom or a chlorine atom. L ^2A1 and L ^2B1 are independent of each other. a single _{bond, -C 2 H 4 -, -} CH = CH -, - C≡C -, - COO -, - OCO -, - CH 2 O -, - OCH 2 -, - CF 2 O- or -OCF Represents _2- ^{X 2A1} and X ^2B1 are independent of each other, with -F, -Cl, -CN, -NCS, -CF ₃ , -OCF ₃ , and at least one hydrogen atom substituted with a halogen atom. Represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms in which at least one hydrogen atom is replaced with a halogen atom. Y ^2A1 , Y ^2A2 , Y ^2B1 and Y ^2B2 are independent of each other. Then, it represents a hydrogen atom or a fluorine atom. ^{B 2A1} and b 2B1 represent 1, 2, 3 or 4 independently of each other.)

In the general formula (A) and the general formula (B), R ^2A1 and R ^2B1 are independent of each other and have an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, and 2 carbon atoms. An alkenyl group of ~ 8 or an alkenyloxy group having 2 to 8 carbon atoms is preferable, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms or carbon. An alkenyloxy group having 2 to 5 atoms is preferable, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 2 to 5 carbon atoms is more preferable, and an alkyl group having 2 to 5 carbon atoms or an alkyl group having 2 to 5 carbon atoms is preferable. An alkenyl group of 3 is more preferable, and an alkoxy group having 3 carbon atoms (propenyl group) is particularly preferable.

^{R 2A1} and R ^2B1 are preferably alkyl groups when reliability is important, and alkenyl groups when reduction in viscosity is important.

When ^{the ring structure to which R 2A1} and R ^2B1 are bonded is a phenyl group (aromatic), R ^2A1 and R ^2B1 are linear alkyl groups having 1 to 5 carbon atoms and linear carbon atoms of 1. Alkoxy groups of ~ 4 and alkenyl groups of 4-5 carbon atoms are preferred.
When ^{the ring structure to which R 2A1} and R ^2B1 are bonded is a saturated ring structure such as cyclohexane, pyran and dioxane, R ^2A1 and R ^2B1 are linear alkyl groups having 1 to 5 carbon atoms and linear. An alkoxy group having 1 to 4 carbon atoms and a linear alkenyl group having 2 to 5 carbon atoms are preferable. In order to stabilize the liquid crystal composition, the total of carbon atoms and oxygen atoms, if present, is preferably 5 or less, and is preferably linear.

When R ^2A1 and R ^2B1 are alkenyl groups, it is preferably selected from the groups represented by any of the following formulas (R1) to (R5).

（式（Ｒ１）〜（Ｒ５）中の黒点は結合手を表す。）

(Black dots in equations (R1) to (R5) represent bonds.)

In the general formula (A) and the general formula (B), C ^2A1 and C ^2B1 are aromatic when it is required to increase the refractive index anisotropy (Δn) independently of each other. Preferably, it is aliphatic in order to improve the response speed.
It is more preferable that C ^2A1 and C ^2B1 are selected from the groups represented by any of the following formulas (C1) to (C8).

L ^2A1 and ^{L 2B1,} independently of one another, a single _{bond, -CH 2 O -, - OCH} 2 -, - CF 2 O- or -OCF ₂ -, more preferably a single bond, _-CH 2 O-or - CF ₂ O-it is preferably a single bond or _-CF 2 O-are Konomashikui.
^{L 2A1} sandwiched between C ^2A1 is preferably a single bond. Further, ^{it is preferable that L 2B1} sandwiched between ^{C 2B} 1 is a single bond.

X ^2A1 and X ^2B1 are independent of each other, _{preferably -F, -Cl, -CF 3} or -OCF ₃ , preferably -F or -OCF ₃ , and preferably -F. preferable.
It is preferable that Y ^2A1 , Y ^2A2 , Y ^2B1 and Y ^2B2 are all fluorine atoms, or one in the same molecule is a fluorine atom and the other is a hydrogen atom.

b ^2A1 and b ^2B1 are preferably 1, 2 or 3 independently of each other, and preferably 2 or 3 when the upper limit temperature of the liquid crystal phase of the liquid crystal composition is important. When the viscosity and dielectric anisotropy of the product are emphasized, it is preferably 1 or 2.

As the compound represented by the general formula (A), for example, a compound represented by the general formula (A1) or the general formula (A2) is preferable.

（一般式（Ａ１）において、Ｒ^７は炭素原子数１〜７個のアルキル基、炭素原子数１〜７個のアルコキシ基又は炭素原子数２〜７個のアルケニル基を表す。Ｙ^１２〜Ｙ^２３は相互に独立して水素原子又はフッ素原子を表す。）
（一般式（Ａ２）において、Ｒ^１は炭素原子数１〜７のアルキル基、炭素原子数１〜７のアルコキシ基、炭素原子数２〜７のアルケニル基、炭素原子数３〜７のアルケニルオキシ基を表す。Ｙ^４０〜Ｙ^４４は、それぞれ独立して水素原子又はフッ素原子を表す。）

(In the general formula (A1), R ⁷ represents an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, or an alkenyl group having 2 to 7 carbon atoms. Y ^{12 to} Y. ²³ represents a hydrogen atom or a fluorine atom independently of each other.)
(In the general formula (A2), R ¹ is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, and an alkenyloxy having 3 to 7 carbon atoms. Represents a group. Y ^{40 to Y 44} independently represent a hydrogen atom or a fluorine atom.)

More specifically, the compound represented by the general formula (A) is preferably a compound represented by the general formulas (A-1) to (A-31).

（式（Ａ−１）〜（Ａ−３１）中、Ｒ^２Ａ１は、炭素原子数１から７のアルキル基、炭素原子数１から７のアルコキシ基又は炭素原子数２から７のアルケニル基又は炭素原子数２から７のアルケニルオキシ基である。Ｒ^２Ａ１上の１個又は２個以上の水素原子は、相互に独立して、フッ素原子又は塩素原子で置換されていてもよい。）

(In formulas (A-1) to (A-31), R ^2A1 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, or an alkenyl group or carbon having 2 to 7 carbon atoms. ^{It is an alkoxyoxy} group having 2 to 7 atoms. One or two or more hydrogen atoms on R 2A1 may be independently substituted with a fluorine atom or a chlorine atom.)

Further, the compound represented by the general formula (A) may be, for example, any compound represented by the general formulas (A3), (A4) and (A5).

（一般式（Ａ３）（Ａ４）及び（Ａ５）において、Ｒ^１、Ｒ^２及びＲ^３は相互に独立して炭素原子数１〜７個のアルキル基、炭素原子数１〜７個のアルコキシ基又は炭素原子数２〜７個のアルケニル基を表す。Ｙ^１〜Ｙ^５、Ｙ^２４〜Ｙ^３５は相互に独立して水素原子又はフッ素原子を表す。一般式（Ａ３）（Ａ４）において、Ｃ^２Ａ１は一般式（Ａ）のＣ^２Ａ１と同じ意味を表す。ａ、ｂは相互に独立して０又は１を表す。）

(In the general formula (A3) (A4) and ^{(A5), R 1, R} 2 and ^{R 3} independently of one another carbon atom 1-7 alkyl groups, 1 to 7 carbon atoms alkoxy groups Alternatively, it represents an alkoxy group having 2 to 7 carbon atoms. Y ^{1 to Y 5} and Y ^{24 to Y 35} represent hydrogen atoms or fluorine atoms independently of each other. In the general formulas (A3) and (A4), C ^2A1 is .a representing the same meaning as ^{C 2A1} of the general formula (a), b represents 0 or 1 independently of each other.)

More specifically, as the compound represented by the general formula (A), it is preferable to use one or more selected from the compounds represented by the formulas (A-32) to (A-47).

（式（Ａ−３２）〜式（Ａ−４７）において、Ｒ^２Ａ１は一般式（Ａ）のＲ^２ａ１と同じ意味を表す。）

(In formulas (A-32) to (A-47), R ^2A1 has the same meaning as ^{R 2a1 in the} general formula (A).)

The compound represented by the general formula (B) is preferably a compound represented by the general formulas (B-1) to (B-6).

（一般式（Ｂ−１）〜（Ｂ−６）において、Ｒ^２Ｂ１は、炭素原子数１から７のアルキル基、炭素原子数１から７のアルコキシ基、炭素原子数２から７のアルケニル基又は炭素原子数２から７のアルケニルオキシ基である。Ｒ^２Ｂ１上の１個又は２個以上の水素原子は、相互に独立して、フッ素原子又は塩素原子で置換されていてもよい。）

(In the general formulas (B-1) to (B-6), R ^2B1 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyl group having 2 to 7 carbon atoms. It is an alkoxyoxy group having 2 to 7 carbon atoms. ^{One or two or more hydrogen atoms on R 2B1} may be independently substituted with a fluorine atom or a chlorine atom.)

When the reliability of the liquid crystal composition is emphasized, the general formulas (A-1) to (A-11), (A-16) to (A-20) and the general formulas (B-1) to (B-4) It is preferable to use a compound selected from the group represented by), among which the general formulas (A-1), (A-2), (A-4), (A-17) and (A-20) are used. It is more preferable to select from the represented group.
When importance is attached to low viscosity, the groups represented by the general formulas (A-12) to (A-15), (A-21) to (A-28) and (B-5) to (B-6). It is preferable to use a compound selected from, and among them, select from the group represented by (A-12), (A-13), (A-22), (A-23) and (A-26). Is more preferable.

In the present embodiment, the compound represented by the general formula (A) and / or the general formula (B) contained in the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23. The content is appropriately adjusted according to the required performance such as solubility at low temperature, transition temperature, electrical reliability, birefringence, and dielectric anisotropy.

The lower limit of the preferable content of the compounds represented by the general formulas (A) and (B) with respect to the total mass of the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23 is For example, it is 1% by mass, more preferably 10% by mass, and preferably 20% by mass. The upper limit of the preferable content is, for example, 95% by mass, preferably 80% by mass, based on the total mass of the first liquid crystal composition 21, the second liquid crystal composition 22, and / or the third liquid crystal composition 23. , 70% by mass is preferable, 60% by mass is preferable, and 50% by mass is more preferable.

In the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23, when it is necessary to keep the viscosity low and increase the response speed, the above lower limit value and upper limit value are lowered. Is preferable. _{Further, when it is necessary to keep the phase transition temperature (TNI} ) of the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23 high and to have good temperature stability, the above It is preferable to lower the lower limit value and the upper limit value of. Further, when it is desired to increase the dielectric anisotropy (Δε) in order to keep the drive voltage low, it is preferable to increase the above lower limit value and upper limit value.

(Dielectrically neutral liquid crystal compound)
Examples of the dielectrically neutral liquid crystal compound include a compound represented by the general formula (L). The liquid crystal compound represented by the general formula (L) has a dielectric anisotropy (Δε) value of -2 to 2, and corresponds to a dielectrically neutral compound.
The compound represented by the general formula (L) preferably contains at least 1 type, preferably 1 type to 10 types, and particularly preferably 2 to 8 types.

（式（Ｌ）中、Ｒ^２１及びＲ^２２はお互い独立して炭素原子数１から１０のアルキル基又は炭素原子数２から１０のアルケニル基を表す。これらの基中に存在する１個のメチレン基又は隣接していない２個以上のメチレン基は−Ｏ−又は−Ｓ−に置換されても良く、またこれらの基中に存在する１個又は２個以上の水素原子はフッ素原子又は塩素原子に置換されても良い。Ｍ^２１、Ｍ^２２及びＭ^２３はお互い独立して（ａ）トランス−１，４−シクロへキシレン基（この基中に存在する１個のメチレン基又は隣接していない２個以上のメチレン基は−Ｏ−又は−Ｓ−に置き換えられてもよい）、（ｂ）１，４−フェニレン基（この基中に存在する１個の−ＣＨ＝又は隣接していない２個以上の−ＣＨ＝は窒素原子に置き換えられてもよい）、２−フルオロ−１，４−フェニレン基、３−フルオロ−１，４−フェニレン基、３，５−ジフルオロ−１，４−フェニレン基及び（ｃ）１，４−シクロヘキセニレン基、１，４−ビシクロ［２．２．２］オクチレン基、ピペリジン−２，５−ジイル基、ナフタレン−２，６−ジイル基、デカヒドロナフタレン−２，６−ジイル基及び１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基からなる群より選ばれる基を表す。上記の基（ａ）、基（ｂ）及び基（ｃ）はそれぞれ独立してシアノ基、フッ素原子又は塩素原子で置換されていても良い。ｐは０、１又は２を表す。Ｌ^２１及びＬ^２２はお互い独立して単結合、−ＣＨ_２ＣＨ_２−、−（ＣＨ_２）_４−、−ＯＣＨ_２−、−ＣＨ_２Ｏ−、−ＯＣＦ_２−、−ＣＦ_２Ｏ−、−ＣＨ＝ＣＨ−、−ＣＨ＝Ｎ−Ｎ＝ＣＨ−又は−Ｃ≡Ｃ−を表す。Ｌ^２２が複数存在する場合は、それらは同一でも良く異なっていても良い。Ｍ^２３が複数存在する場合は、それらは同一でも良く異なっていても良い。）

(In the formula (L), R ²¹ and R ²² independently represent an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms. One methylene present in these groups. Two or more methylene groups that are group or non-adjacent may be substituted with -O- or -S-, and one or more hydrogen atoms present in these groups are fluorine or chlorine atoms. ^{M 21} , M ²² and M ²³ may be substituted with (a) a trans-1,4-cyclohexylene group (one methylene group present in this group or not adjacent to each other) independently of each other. Two or more methylene groups may be replaced with -O- or -S-), (b) 1,4-phenylene group (one -CH = or non-adjacent 2 present in this group). More than one -CH = may be replaced with a nitrogen atom), 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 3,5-difluoro-1,4-phenylene Group and (c) 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, piperidine-2,5-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene Represents a group selected from the group consisting of -2,6-diyl group and 1,2,3,4-tetrahydronaphthalene-2,6-diyl group. The above groups (a), group (b) and group (c). ) May be independently substituted with a cyano group, a fluorine atom or a chlorine atom. P represents 0, 1 or 2. L ²¹ and L ²² are independent of each other and are single-bonded, −CH ₂ CH _{2 -, - (CH 2) 4} -, - OCH 2 -, - CH 2 O -, - OCF 2 -, - CF 2 O -, - CH = CH -, - CH = N-N = CH- or -C If .L ²² representing the ≡C- there are multiple, if they where good .M ²³ be different may be the same there are two or more, they may be different may be the same.)

In the compound represented by the general formula (L), R ²¹ and R ²² are independent of each other as an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms (1 existing in these groups). One methylene group or two or more non-adjacent methylene groups are substituted with -O- or -S-, and one or more hydrogen atoms present in these groups are fluorine atoms or It also includes those substituted with chlorine atoms), preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or 3 to 6 carbon atoms. The alkenyloxy group is more preferable, and an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms is particularly preferable.

When reliability is important, it is preferable that both ^RL1 and ^{RL2 are alkyl groups.} When it is important to reduce the volatility of the compound, it is preferable that both ^RL1 and ^{RL2 are alkoxy groups.} It is preferred when emphasizing a reduction in viscosity is at least one of R ^L1 and R ^L2 is an alkenyl group.
In the general formula (L), the number of halogen atoms present in the molecule is preferably 0, 1, 2 or 3, preferably 0 or 1, and 1 is preferable when compatibility with other liquid crystal molecules is important. ..

R ²¹ and R ²² are linear alkyl groups having 1 to 5 carbon atoms and linear carbon atoms 1 to 4 when the ring structure to which they are bonded is a phenyl group (aromatic). Alkoxy group and alkenyl group having 4 to 5 carbon atoms are preferable.
R ²¹ and R ²² are linear alkyl groups having 1 to 5 carbon atoms and linear carbon atoms when the ring structure to which they are bonded is a saturated ring structure such as cyclohexane, pyran, or dioxane. Alkoxy groups having a number of 1 to 4 and linear alkenyl groups having 2 to 5 carbon atoms are preferable.
In ^{order to stabilize the liquid crystal composition, R 21} and R ²² preferably have a total of 5 or less carbon atoms and oxygen atoms if present, and are preferably linear.

When ^RL1 and ^RL2 are alkenyl groups, it is preferably selected from the groups represented by any of the formulas (R11) to (R15).

（各式中の黒点は環構造中の炭素原子を表す。）

(The black dots in each equation represent carbon atoms in the ring structure.)

M ²¹ , M ²² and M ²³ are independently trans-1,4-cyclohexylene groups (one CH ₂ group existing in this group or two non-adjacent CH ₂ groups are oxygen atoms. 1,4-phenylene group (including one in which one or more CH groups present in this group are substituted with a nitrogen atom), 3-fluoro-1 , 4-phenylene group, 3,5-difluoro-1,4-phenylene group, 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, piperidine-1,4-diyl Group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group is preferable, and trans-1,4-cyclohexylene. A group, a 1,4-phenylene group or a 1,4-bicyclo [2.2.2] octylene group is more preferable, and a trans-1,4-cyclohexylene group or a 1,4-phenylene group is particularly preferable.

M ²¹ , M ²² and M ²³ are preferably aromatic when it is required to increase the refractive index anisotropy (Δn). M ²¹ , M ²² and M ²³ are preferably aliphatic in order to improve the response rate, and are independently trans-1,4-cyclohexylene group, 1,4-phenylene group and 2-. Fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 3,5-difluoro-1,4-phenylene group, 1,4-cyclohexenylene group, 1,4-bicyclo [2. 2.2] Octylene group, piperidine-1,4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6 -It is preferably any of the diyl groups, more preferably the structure represented by any of the following formulas (M1) to (M8), and the trans-1,4-cyclohexylene group or 1, It is more preferable to represent a 4-phenylene group.

In the general formula (L), p is preferably 0, 1 or 2, and more preferably 0 or 1.
L ²¹ and ^{L 22} are each independently a single _{bond, -CH 2 CH 2 -, -} (CH 2) 4 -, - OCH 2 -, - CH 2 O -, - OCF 2 -, - CF 2 O- , -CH = CH -, - CH = N-N = CH- or -C≡C-, more preferably a single _{bond, -CH 2 CH 2 -, -} (CH 2) 4 -, - OCH 2 -, - CH ₂ O- or -C ≡ C- is more preferred, and single bond, -CH ₂ CH _2- or -C ≡ C- is even more preferred.

Among the structures formed by the combination of the above options, -CH = CH-CH = CH-, -C≡C-C≡C- and -CH = CH-C≡C- are preferable from the viewpoint of chemical stability. do not have. Further, it is also not preferable that the hydrogen atom in these structures is replaced with the fluorine atom. Further, a structure in which oxygen is bonded to each other, a structure in which sulfur atoms are bonded to each other, and a structure in which sulfur atoms and oxygen atoms are bonded are also not preferable. Further, a structure in which nitrogen atoms are bonded to each other, a structure in which a nitrogen atom and an oxygen atom are bonded, and a structure in which a nitrogen atom and a sulfur atom are bonded are also not preferable.

Specifically, the general formula (L) is preferably a compound represented by the following general formulas (L-1) to (L-25).

（式（Ｌ−１）〜式（Ｌ−２５）で表される化合物において、Ｒ^２３及びＲ^２４は、それぞれ独立的に炭素数１から１０のアルキル基、炭素数１から１０のアルコキシ基、炭素数２から１０のアルケニル基又は炭素数３から１０のアルケニルオキシ基を表す。）

(In the compounds represented by the formulas (L-1) to (L-25), R ²³ and R ²⁴ are independently alkyl groups having 1 to 10 carbon atoms and alkoxy groups having 1 to 10 carbon atoms, respectively. Represents an alkenyl group having 2 to 10 carbon atoms or an alkenyloxy group having 3 to 10 carbon atoms.

In the compounds represented by the formulas (L-1) to (L-25), R ²³ and R ²⁴ independently have an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or carbon. An alkenyl group having 2 to 10 carbon atoms is preferable, and an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 10 carbon atoms is more preferable.

Among the compounds represented by the general formulas (L-1) to (L-25), the general formula (L-1), the general formula (L-2), the general formula (L-3), and the general formula (L). -5), the compound represented by the general formula (L-12), the general formula (L-13), the general formula (L-17), the general formula (L-19) or the general formula (L-25) is preferable. , The compound represented by the general formula (L-1), the general formula (L-3), the general formula (L-5), the general formula (L-12) or the general formula (L-13) is more preferable.

Further, the general formula (L) is preferably a compound represented by the following general formula (L1).

（式（Ｌ１）中、Ｒ^３３及びＲ^３４は、相互に独立して炭素原子数１〜７個のアルキル基、炭素原子数１〜７個のアルコキシ基又は炭素原子数２〜７個のアルケニル基を表す。環Ａは１，４−シクロへキシレン基又は１，４−フェニレン基を表す。Ｙ^６〜Ｙ^１２は相互に独立して水素原子、フッ素原子又はメチル基を表す。Ｚ^１は、単結合、−ＣＯＯ−又は−ＣＨ_２ＣＨ_２−を表し、ｃは相互に独立して０又は１を表す。）

(In the formula (L1), R ³³ and R ³⁴ are independent of each other as an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, or an alkenyl having 2 to 7 carbon atoms. The ring A represents a 1,4-cyclohexylene group or a 1,4-phenylene group. Y ^{6 to Y 12} represent a hydrogen atom, a fluorine atom or a methyl group independently of each other. Z ^{1 represents a group.} , Single bond, -COO- or -CH ₂ CH _2- , and c represents 0 or 1 independently of each other.)

More specifically, as the compound represented by the general formula (L1), it is preferable to use one or more selected from the compounds represented by the formulas (L-26) to (L-34).

（式（Ｌ−２６）〜式（Ｌ−３４）表される化合物において、Ｒ^３３及びＲ^３４は、相互に独立して炭素原子数１〜７個のアルキル基、炭素原子数１〜７個のアルコキシ基又は炭素原子数２〜７個のアルケニル基を表す。）

(In the compounds represented by the formulas (L-26) to (L-34), R ³³ and R ³⁴ are mutually independent alkyl groups having 1 to 7 carbon atoms and 1 to 7 carbon atoms. Represents an alkoxy group or an alkenyl group having 2 to 7 carbon atoms.

In the present embodiment, the content of the liquid crystal compound represented by the general formula (L) contained in the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23 is at a low temperature. It is appropriately adjusted according to the required performance such as solubility, transition temperature, electrical reliability, birefringence, process compatibility, dripping marks, seizure, and dielectric anisotropy (Δε).
The lower limit of the content of the compound represented by the formula (L) with respect to the total mass of the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23 is, for example, 1% by mass. It is preferable, and it is more preferable that it is 50% by mass. The upper limit of the content of the compound represented by the formula (L) with respect to the total mass of the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23 is 85% by mass. It is preferably 65% by mass, more preferably 65% by mass.

When a composition that keeps the viscosity of the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23 low and has a high response speed is required, the above lower limit value and upper limit value are high. Is preferable. _{Further, when it is necessary to keep the phase transition temperature (TNI} ) of the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23 high to obtain a composition having good temperature stability. It is preferable to increase the above lower limit value and upper limit value. Further, when it is desired to increase the dielectric anisotropy (Δε) in order to keep the drive voltage low, it is preferable that the above lower limit value and upper limit value are low.

(Optically active compound)
As the optically active compound (second component), two or more kinds selected so that the temperature dependence of the chiral pitch length is different and the temperature dependence of the selective reflection wavelength (chiral pitch length) becomes zero can be used. can. "Selected so that the temperature dependence of the selective reflection wavelength becomes zero" means that the temperature dependence of the selective reflection wavelength does not become zero in reality, but the temperature dependence when combined is zero as much as possible. It means that two or more kinds of optically active compounds are selected so as to have a value close to.
In the present embodiment, as the optically active compound, one of the two types of optically active compounds has a positive chiral pitch temperature dependence in the temperature range of 0 to 50 ° C., which is preferable as the normal temperature of the liquid crystal display device, and the other It preferably has a negative chiral pitch temperature dependence. The total content of the optically active compound contained in the liquid crystal composition varies depending on the intended selective reflection wavelength, but is preferably 10% or less, more preferably 8% or less, and particularly preferably 6% or less. The preferable lower limit amount is not particularly limited, but when the liquid crystal twisting force is extremely large, the amount of the optically active compound added to the liquid crystal composition becomes very small, and the selective reflection wavelength and its temperature dependence become large due to a slight deviation in the mixing ratio. It may shift. Although it is affected by the weighing accuracy of the production equipment, if the concentration of the optically active compound is approximately 0.1% or more, the liquid crystal composition can be produced with high accuracy regardless of the production scale.

In the liquid crystal display device 10 of the present embodiment, it is preferable that the first liquid crystal composition 21 contains one or more optically active compounds having the spiral twisting direction as the first direction (for example, the right direction). Further, it is preferable that the second liquid crystal composition 22 contains one or more optically active compounds having a second direction (for example, a left direction) different from the first direction in the spiral twist direction. Further, the third liquid crystal composition 23 preferably contains one or more optically active compounds having the spiral twisting direction as the first direction (for example, the right direction). That is, in the liquid crystal display device 10 of the present embodiment, the adjacent liquid crystal compositions of the first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23 induce different spiral twist directions. It is preferable that the active compound is selectively contained. As a result, in the liquid crystal display device 10 of the present embodiment, the spiral twist directions of the adjacent liquid crystal compositions of the first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23 are different. ing.

As the optically active compound, for example, compounds represented by the following formulas (D-1) to (D-6) can be used.

（式中、Ｒ^９は、炭素原子数１〜１６のアルキル基、炭素原子数１〜１６のアルコキシ基、炭素原子数２〜１６のアルケニル基、炭素原子数３〜１６のアルケニルオキシ基、又は炭素原子数１〜１０のアルコキシ基で置換された炭素原子数１〜１２のアルキル基を表す。Ｒ^１０は、炭素原子数１〜１６のアルキル基、炭素原子数１〜１６のアルコキシ基、炭素原子数２〜１６のアルケニル基、炭素原子数３〜１６のアルケニルオキシ基、炭素原子数１〜１０のアルコキシ基で置換された炭素原子数１〜１２のアルキル基、水素原子、フッ素原子、基中に存在する１個のＣＨ_２基又は隣接していない２個以上のＣＨ_２基が酸素原子により置き換えられても良いトランス−１，４−シクロへキシレン基又は基中に存在する１個の炭素原子又は隣接していない２個以上の炭素原子が窒素原子に置き換えられてもよい１，４−フェニレン基を表し、該１，４−フェニレン基はフッ素原子により置換されていても良い。Ａ^８、Ａ^１０及びＡ^１１は、基中に存在する１個のＣＨ_２基又は隣接していない２個以上のＣＨ_２基が酸素原子により置き換えられても良いトランス−１，４−シクロへキシレン基又は基中に存在する１個の炭素原子又は隣接していない２個以上の炭素原子が窒素原子に置き換えられてもよい１，４−フェニレン基を表し、該１，４−フェニレン基はフッ素原子により置換されていても良い。Ａ^８、Ａ^１０及びＡ^１１は単結合を表していても良い。Ｚ^７、Ｚ^８、Ｚ^９及びＺ^１０はそれぞれ独立的して−ＣＨ_２ＣＨ_２−、−ＣＨ（ＣＨ_３）ＣＨ_２−、−ＣＨ_２ＣＨ（ＣＨ_３）−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ=ＣＨ−、−ＣＦ=ＣＦ−、−Ｃ≡Ｃ−、−Ｏ（ＣＨ_２）_３−、−（ＣＨ_２）_３Ｏ−、−（ＣＨ_２）_４−又は単結合を表す。）

(In the formula, R ⁹ is an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or Represents an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms. R ¹⁰ is an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, and carbon. An alkenyl group having 2 to 16 atoms, an alkenyloxy group having 3 to 16 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms, a hydrogen atom, a fluorine atom, and a group. two or more CH ₂ groups not one CH ₂ group or adjacent present in the one present in the xylene group or groups to be trans-1,4-cyclohexylene be replaced by an oxygen atom A carbon atom or two or more non-adjacent carbon atoms may be substituted with a nitrogen atom to represent a 1,4-phenylene group, and the 1,4-phenylene group may be substituted with a fluorine atom. ⁸ , A ¹⁰ and A ¹¹ _{are trans-1,4-cyclohexylene in which one CH 2} group existing in the group or two or more CH ₂ groups not adjacent to each other may be replaced by an oxygen atom. A group or a 1,4-phenylene group in which one carbon atom existing in the group or two or more carbon atoms not adjacent to each other may be replaced with a nitrogen atom, and the 1,4-phenylene group is fluorine. It may be substituted by an atom. A ⁸ , A ¹⁰ and A ¹¹ may represent a single bond. Z ⁷ , Z ⁸ , Z ⁹ and Z ¹⁰ are independently −CH ₂ CH ₂ −. , -CH (CH ₃ ) CH _{2- , -CH 2} CH (CH ₃ )-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -COO-, -OCO- , -CH = CH -, - CF = CF -, - C≡C -, - O (CH 2) 3 -, - (CH 2) 3 O -, - (CH 2) 4 - or a single bond. )

As the optically active compound, it is preferable to use a binaphthyl chiral compound having a binaphthyl skeleton in which the 1-positions of two naphthalene rings are covalently bonded to each other.
The binaphthyl chiral compound is an optically active compound having a large liquid crystal twisting force. Therefore, by using the binaphthyl chiral compound as the optically active compound, the content of the optically active compound in the first liquid crystal composition 21 and / or the second liquid crystal composition 22 can be reduced. As a result, it is possible to suppress an increase in viscosity, a decrease in phase transition temperature and a decrease in storage stability of the first liquid crystal composition 21 and / or the second liquid crystal composition 22 due to the inclusion of the optically active compound, which is preferable.
As the binaphthyl chiral compound, for example, a compound represented by the following formula (D-7) is preferable.

（式（Ｄ−７）中、Ｒ^８及びＲ^９は相互に独立して炭素原子数１〜７個のアルキル基、炭素原子数１〜７個のアルコキシ基又は炭素原子数２〜７個のアルケニル基を表す。環Ｄ、Ｅ、Ｆ、Ｇは相互に独立して１，４−シクロへキシレン基又は１，４−フェニレン基を表す。Ｚ^５及びＺ^６は相互に独立して単結合又は−ＣＯＯ−を表し、ｅ及びｆは相互に独立して０又は１を表す。）

(In the formula (D-7), R ⁸ and R ⁹ are independent of each other and have an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, or an alkoxy group having 2 to 7 carbon atoms. an alkenyl group. ring D, E, F, G are .Z ⁵ and ^{Z 6} represents a cyclohexylene group or 1,4-phenylene group independently of one another 1,4-cyclohexylene is a single bond, independently of one another Or -COO-, and e and f represent 0 or 1 independently of each other.)

As the binaphthyl chiral compound represented by the formula (D-7), for example, the compounds represented by the following formulas (3-1) to (3-4) are preferable.

The compounds represented by the formulas (3-1) and (3-3) induce a right-handed spiral twisting direction. Further, the compounds represented by the formulas (3-2) and (3-4) induce a left-handed spiral twisting direction.

As the optically active compound, for example, a compound represented by the following formula (E1) may be used.

（式（Ｅ１）中、Ｋ^１−４は、互いに独立して、アネレートされたベンゼン、シクロヘキサンまたはシクロヘキセンであり、ここで、１つまたは２つ以上のＣＨ基は、随意に、Ｎにより置換されており、１つまたは２つ以上のＣＨ_２基は、随意に、Ｏおよび／またはＳにより、Ｏおよび／またはＳ原子が互いに直接結合しないように置換されており、
Ｕ^１−４は、互いに独立して、ＣＨ_２、Ｏ、Ｓ、ＣＯ、ＮＨまたはＣＦ_２であり、
Ｖ^１−４は、互いに独立して、Ｕ^１の意味の１つを有し、ただし、Ｏ、ＳおよびＮＨは、互いに直接隣接していないか、または単結合を示し、
Ｚは、Ｃ、Ｓｉ、Ｇｅ、ＳｎまたはＴｉであり、
Ｘ_１−１２は、互いに独立して、Ｒ、Ｐ−Ｓｐまたは−Ｗ^１−Ａ^１−（Ｗ^２−Ａ^２）_ｍ−Ｒであり、
Ｒは、各々の存在において、独立して、Ｈ、Ｆ、Ｃｌ、Ｂｒ、Ｉ、ＣＮ、ＮＯ_２、ＯＨ、ＮＣＳ、ＳＦ_５、１〜４０個のＣ原子を有し、非置換であるか、Ｆ、Ｃｌ、Ｂｒ、ＩもしくはＣＮにより単置換または多置換されている直鎖状もしくは分枝状アルキルであり、ここで、１つもしくは２つ以上のＣＨ_２基は、随意に、各々の場合において、互いに独立して、−Ｏ−、−Ｓ−、−ＮＨ−、−ＮＲ０−、−ＳｉＲ^０Ｒ^００−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＯＣＯ−Ｏ−、−Ｓ−ＣＯ−、−ＣＯ−Ｓ−、−ＳＯ_２−、−ＣＧ^１＝ＣＧ^２−もしくは−Ｃ≡Ｃ−により、２個のＯもしくは２個のＳ原子が互いに直接結合しないように置換されているか、またはＰ−Ｓｐ−を示し、
Ｒ^０およびＲ^００は、互いに独立して、Ｈまたは１〜１２個のＣ原子を有するアルキルであり、
Ｇ^１およびＧ^２は、互いに独立して、Ｈ、Ｆ、ＣｌまたはＣＮであり、
Ｐは、反応性の基であり、
Ｓｐは、スペーサー基または単結合であり、
Ａ^１およびＡ^２は、各々の存在において、独立して、置換もしくは非置換芳香族もしくは脂環式環、または２つもしくは３つ以上の縮合した芳香族もしくは脂環式環を含む基であり、ここで、これらの環は、随意に、Ｎ、ＯおよびＳから選択された１個または２個以上のヘテロ原子を含み、
Ｗ^１およびＷ^２は、各々の存在において、独立して、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−Ｓ−ＣＯ−、−ＣＯ−Ｓ−、−Ｏ−ＣＯＯ−、−ＣＯ−ＮＲ^０−、−ＮＲ^０−ＣＯ−、−ＯＣＨ_２−、−ＣＨ_２Ｏ−、−ＳＣＨ_２−、−ＣＨ_２Ｓ−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＦ_２Ｓ−、−ＳＣＦ_２−、−ＣＨ_２ＣＨ_２−、−ＣＦ_２ＣＨ_２−、−ＣＨ_２ＣＦ_２−、−ＣＦ_２ＣＦ_２−、−ＣＨ＝Ｎ−、−Ｎ＝ＣＨ−、−Ｎ＝Ｎ−、−ＣＨ＝ＣＨ−、−ＣＨ＝ＣＲ^０−、−ＣＲ^０＝ＣＲ^００−、−ＣＧ^１＝ＣＧ^２−、−Ｃ≡Ｃ−、−ＣＨ＝ＣＨ−ＣＯＯ−、−ＯＣＯ−ＣＨ＝ＣＨ−または単結合であり、ｍは、各々の存在において、独立して、０、１、２または３である。）

(In formula (E1), K ^1-4 are benzene, cyclohexane or cyclohexene annealed independently of each other, where one or more CH groups are optionally substituted with N. and, one or more CH ₂ groups may optionally by O and / or S, O and / or S atoms are substituted so as not linked directly to one another,
U ^1-4 are independent of each other and are CH ₂ , O, S, CO, NH or CF ₂ .
V ^1-4 are independent of each other and have ^one of the meanings of U 1, where O, S and NH are not directly adjacent to each other or indicate a single bond.
Z is C, Si, Ge, Sn or Ti,
X _1-12 are R, P-Sp or -W ^1- A ^1- (W ^2- A ² ) _m -R independently of each other.
Does R, in each presence, independently have H, F, Cl, Br, I, CN, NO ₂ , OH, NCS, SF ₅ , 1 to 40 C atoms and are unsubstituted? , F, Cl, Br, I or CN mono- or poly-substituted linear or branched alkyl, where one or more CH ₂ groups are optionally each. in case, independently of one another, -O -, - S -, - NH -, - NR0 -, - SiR 0 R 00 -, - CO -, - COO -, - OCO -, - OCO-O -, - S-CO-, -CO-S-, -SO _2- , -CG ¹ = CG ^2- or -C ≡ C- are substituted so that two O or two S atoms are not directly bonded to each other. Or indicates P-Sp-,
R ⁰ and R ⁰⁰ are alkyl having H or 1 to 12 C atoms, independent of each other.
G ¹ and G ² are independent of each other and are H, F, Cl or CN.
P is the basis of reactivity,
Sp is a spacer group or a single bond,
A ¹ and A ² are groups that, in their respective presence, independently contain a substituted or unsubstituted aromatic or alicyclic ring, or two or more condensed aromatic or alicyclic rings. Here, these rings optionally contain one or more heteroatoms selected from N, O and S.
W ¹ and W ² independently in their respective existence are -O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O. -COO-, ^{-CO-NR 0-} , -NR ^0- CO-, -OCH _2- , -CH ₂ O-, -SCH _2- , -CH ₂ S-, -CF ₂ O-, -OCF _{2- , -CF 2 S -, - SCF} 2 -, - CH 2 CH 2 -, - CF 2 CH 2 -, - CH 2 CF 2 -, - CF 2 CF 2 -, - CH = N -, - N = CH -, -N = N-, -CH = CH-, -CH = CR ^0- , -CR ⁰ = CR ^00- , -CG ¹ = CG ^2- , -C≡C-, -CH = CH-COO- , -OCO-CH = CH- or single bond, where m is 0, 1, 2 or 3 independently in each presence. )

As the compound represented by the formula (E1), for example, the compounds represented by the following formulas (E1-1) to (E1-3) are preferable.

As the optically active compound, for example, a compound represented by the following formula (E2) may be used.

（式（Ｅ２）中、Ｘ^１、Ｘ^２、Ｙ^１およびＹ^２は、互いに独立して、Ｈ、Ｆ、Ｃｌ、Ｂｒ、Ｉ、ＣＮ、ＳＣＮ、ＳＦ_５、２５個までのＣ原子を有する直鎖状または分枝状アルキルであって、非置換であるか、あるいはＦ、Ｃｌ、Ｂｒ、ＩまたはＣＮにより一置換または多置換されていてもよく、また、１つまたは２つ以上の非隣接ＣＨ_２基が、各々の場合において互いに独立して、−Ｏ−、−Ｓ−、−ＮＨ−、−ＮＲ^０−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＯＣＯ−Ｏ−、−Ｓ−ＣＯ−、−ＣＯ−Ｓ−、−ＣＨ＝ＣＨ−または−Ｃ≡Ｃ−によって、Ｏ原子および／またはＳ原子が互いに直接結合しないように置換されていてもよい前記アルキル、あるいは任意選択でＬであり、
Ｒ^０は、Ｈまたは、１個から４個のＣ原子を有するアルキルであり、
ｘ１およびｘ２は、互いに独立して、０、１または２であり、
ｙ１およびｙ２は、互いに独立して、０、１、２、３または４であり、
ＢおよびＣは、互いに独立して、芳香族または部分飽和もしくは全飽和脂肪族の６員環であり、１つまたは２つ以上のＣＨ基がＮで置換され、かつ１つまたは２つ以上のＣＨ_２基がＯおよび／またはＳで置換されていてもよく、
Ｗ^１およびＷ^２の一方が−Ｚ^１−Ａ^１−（Ｚ^２−Ａ^２）_ｍ−Ｒであり他方がＲ^１またはＡ^３であるか、あるいはＷ^１およびＷ^２の両方が−Ｚ^１−Ａ^１−（Ｚ^２−Ａ^２）_ｍ−Ｒであり、かつＷ^１およびＷ^２が同時にＨではなく、または、
Ｃ−Ｗ^１−（−Ｗ^２−）が下記式（Ｅ２−１）または下記（Ｅ２−２）であり、
Ｕ^１およびＵ^２は、互いに独立して、ＣＨ_２、Ｏ、Ｓ、ＣＯまたはＣＳであり、
Ｖ^１およびＶ^２は、互いに独立して、(ＣＨ_２）ｎであり、４つまでの非隣接ＣＨ_２基がＯおよび／またはＳで置換されていてもよく、かつＶ^１およびＶ^２の１つ、または
Ｃ−Ｗ^１−（−Ｗ^２−）が下記式（Ｅ２−３）の場合には、Ｖ^１およびＶ^２の一方または両方ともが単結合を意味し、
ｎは１〜７の整数であり、
Ｚ^１およびＺ^２は、互いに独立して、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−Ｏ−ＣＯＯ−、−ＣＯ−ＮＲ^０−、−ＮＲ^０−ＣＯ−、−ＯＣＨ_２−、−ＣＨ_２Ｏ−、−ＳＣＨ_２−、−ＣＨ_２Ｓ−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＦ_２Ｓ−、−ＳＣＦ_２−、−ＣＨ_２ＣＨ_２−、−ＣＦ_２ＣＨ_２−、−ＣＨ_２ＣＦ_２−、−ＣＦ_２ＣＦ_２−、−ＣＨ＝Ｎ−、−Ｎ＝ＣＨ−、−Ｎ＝Ｎ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＨ−、−ＣＨ＝ＣＦ−、−ＣＦ＝ＣＦ−、−Ｃ≡Ｃ−、−ＣＨ＝ＣＨ−ＣＯＯ−、−ＯＣＯ−ＣＨ＝ＣＨ−または単結合であり、
Ａ^１、Ａ^２およびＡ^３が、互いに独立して、さらに１つまたは２つ以上のＣＨ基がＮで置換されていてもよい１，４−フェニレン、さらに１つまたは２つの非隣接ＣＨ_２基がＯおよび／またはＳで置換されていてもよい１，４−シクロヘキシレン、１，３−ジオキソラン−４，５−ジイル、１，４−シクロヘキセニレン、１，４−ビシクロ−（２，２，２）−オクチレン、ピペリジン−１，４−ジイル、ナフタレン−２，６−ジイル、デカヒドロナフタレン−２，６−ジイル、または１，２，３，４−テトラヒドロナフタレン−２，６−ジイルであり、これらのすべての基は非置換であるか、またはＬによって一置換または多置換されていてもよく、またＡ^１は単結合でもよく、
Ｌは、ハロゲンまたは、１〜７個のＣ原子を有する、シアノ、ニトロアルキル、アルコキシ、アルキルカルボニルまたはアルコキシカルボニル基であって、ここで１つまたは２つ以上のＨ原子がＦまたはＣｌで置換されていてもよく、
ｍは、それぞれの場合に独立して、０、１、２または３であり、ならびに
ＲおよびＲ^１は、互いに独立して、Ｈ、Ｆ、Ｃｌ、Ｂｒ、Ｉ、ＣＮ、ＳＣＮ、ＯＨ、ＳＦ_５、２５個までのＣ原子を有する直鎖状または分枝状アルキルであって、非置換であるか、またはＦ、Ｃｌ、Ｂｒ、ＩもしくはＣＮで一置換または多置換されていてもよく、また、１つまたは２つ以上の非隣接ＣＨ_２基が、各々の場合において互いに独立して、−Ｏ−、−Ｓ−、−ＮＨ−、−ＮＲ^０−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＯＣＯ−Ｏ−、−Ｓ−ＣＯ−、−ＣＯ−Ｓ−、−ＣＨ＝ＣＨ−または−Ｃ≡Ｃ−によって、Ｏ原子および／またはＳ原子が互いに直接結合しないように置換されていることも可能である、前記アルキル基である。）

(In formula (E2), X ¹ , X ² , Y ¹ and Y ² have up to 25 C atoms, H, F, Cl, Br, I, CN, SCN, SF _{5, independent of each other.} It may be a linear or branched alkyl, unsubstituted, or mono- or poly-substituted with F, Cl, Br, I or CN, and one or more non-substituted. _Two adjacent CHs are independent of each other in each case, -O-, -S-, -NH-, -NR ^0- , -CO-, -COO-, -OCO-, -OCO-O-, The alkyl, or optionally, which may be substituted by -S-CO-, -CO-S-, -CH = CH- or -C≡C- so that the O and / or S atoms do not bond directly to each other. L in selection,
R ⁰ is an alkyl having H or 1 to 4 C atoms.
x1 and x2 are 0, 1 or 2 independently of each other.
y1 and y2 are 0, 1, 2, 3 or 4, independent of each other.
B and C are independently aromatic or partially saturated or fully saturated aliphatic 6-membered rings, with one or more CH groups substituted with N and one or more CH groups. _Two CH groups may be substituted with O and / or S,
One of W ¹ and W ² is −Z ¹ −A ¹ − (Z ² −A ² ) _m −R and the other is R ¹ or A ³ , or ^{both W 1} and W ² are −Z ¹ −A ¹ − (Z ² −A ² ) _m −R, and W ¹ and W ² are not H at the same time, or
C-W ^1- (-W ^2- ) is the following formula (E2-1) or the following (E2-2).
U ¹ and U ² _{are CH 2} , O, S, CO or CS, independent of each other.
V ¹ and ^{V 2} independently of one another, _(CH 2) n, and may be non-adjacent CH ₂ groups of up to four substituted with O and / or S, and the ^{V 1} and ^{V 2} When one or C-W ^1- (-W ^2- ) is the following formula (E2-3), one or both of ^{V 1} and V ^{2 mean a single bond.}
n is an integer from 1 to 7
Z ¹ and Z ² are independent of each other, -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, ^{-CO-NR 0-} , -NR ^0- CO. -, -OCH _2- , -CH ₂ O-, -SCH _2- , -CH ₂ S-, -CF ₂ O-, -OCF _2- , -CF ₂ S-, -SCF _2- , -CH ₂ CH _2- , -CF ₂ CH _2- , -CH ₂ CF _2- , -CF ₂ CF _2- , -CH = N-, -N = CH-, -N = N-, -CH = CH-, -CF = CH-, -CH = CF-, -CF = CF-, -C≡C-, -CH = CH-COO-, -OCO-CH = CH- or single bond.
A ¹ , A ² and A ³ are independent of each other, with 1,4-phenylene in which one or more CH groups may be substituted with N, and one or two non-adjacent CH ₂ 1,4-Cyclohexylene, 1,3-dioxolane-4,5-diyl, 1,4-cyclohexenylene, 1,4-bicyclo- (2, whose groups may be substituted with O and / or S) 2,2) -octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, or 1,2,3,4-tetrahydronaphthalene-2,6-diyl All of these groups may be unsubstituted or mono- or poly-substituted by L, and A ¹ may be single-bonded.
L is a halogen or a cyano, nitroalkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl group having 1 to 7 C atoms, where one or more H atoms are substituted with F or Cl. May have been
m is 0, 1, 2 or 3 independently in each case, and R and R ¹ are independent of each other, H, F, Cl, Br, I, CN, SCN, OH, SF. _A linear or branched alkyl having up to 5 or 25 C atoms, which may be unsubstituted or mono- or poly-substituted with F, Cl, Br, I or CN. also, one or more non-adjacent CH ₂ groups, in each case independently of one another, -O -, - S -, - NH -, - NR 0 -, - CO -, - COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CH = CH- or -C≡C- are used to replace the O and / or S atoms so that they do not bond directly to each other. The alkyl group, which can also be. )

As the compound represented by the formula (E2), for example, the compounds represented by the following formulas (E2-4) to (E2-7) are preferable.

As the optically active compound, for example, a compound represented by the following formula (E3) may be used.

（式（Ｅ３）中、Ｌ^１１、Ｌ^２１は、各々、同一にまたは異なって、Ｆ、Ｃｌ、Ｂｒ、Ｉ、ＣＮ、ＳＣＮ、ＳＦ_５、非置換であっても、Ｆ、Ｃｌ、Ｂｒ、ＩもしくはＣＮによって単置換もしくは多置換されていてもよい２５個までのＣ原子を有する直鎖状もしくは分枝状アルキルであって、それは、１以上の非隣接ＣＨ_２基が各々の場合において互いに独立して、−Ｏ−、−Ｓ−、−ＮＨ−、−ＮＲ^０−、−ＣＯ−、−Ｃ（Ｏ）Ｏ−、−ＯＣ（Ｏ）−、−ＯＣ（Ｏ）−Ｏ−、−ＳＣ（Ｏ）−、−Ｃ（Ｏ）Ｓ−、−ＣＨ＝ＣＨ−または−Ｃ≡Ｃ−によりＯおよび／またはＳ原子が互いに直接結合しないように置き換えられていることもまた可能である該アルキル、または、Ｌ^３１によって、任意に単置換もしくは多置換されていてもよい２０個までのＣ原子を有するシクロアルキルもしくはアリールであり、
Ｒ^０は、Ｈまたは１〜４個のＣ原子を有するアルキルであり、
Ｍ^１およびＭ^２の一方は−Ｚ^３１−Ａ^３１−（Ｚ^３２−Ａ^３２）ｍ−Ｒ^３１であり、他方はＲ^４１もしくはＡ^４１であり、または、
Ｍ^１およびＭ^２の両方は、同一にまたは異なって、−Ｚ^３１−Ａ^３１−（Ｚ^３２−Ａ^３２）_ｍ−Ｒ^３１であるか、または、
下記式（Ｅ３−１）は、下記式（Ｅ３−２）もしくは下記式（Ｅ３−３）であり、
Ｕ^１およびＵ^２は、各々、同一にまたは異なって、−ＣＨ_２−、−ＣＦ_２−、−Ｏ−、−Ｓ−、−ＣＯ−または−ＣＳ−を示し、
Ｖ^１およびＶ^２は、各々、同一にまたは異なって、単結合または（ＣＨ_２）ｎを示し、ここで３つまでの非隣接ＣＨ_２−基が−Ｏ−および／または−Ｓ−によって置き換えられていてもよく、
Ｚ^１１、Ｚ^１２、Ｚ^２１、Ｚ^２２、Ｚ^３１およびＺ^３２は、各々、同一にまたは異なって、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−Ｏ−ＣＯＯ−、−ＣＯ−ＮＲ^０−、−ＮＲ^０−ＣＯ−、−ＯＣＨ_２−、−ＣＨ_２Ｏ−、−ＳＣＨ_２−、−ＣＨ_２Ｓ−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＦ_２Ｓ−、−ＳＣＦ_２−、−ＣＨ_２ＣＨ_２−、−ＣＦ_２ＣＨ_２−、−ＣＨ_２ＣＦ_２−、−ＣＦ_２ＣＦ_２−、−ＣＨ＝Ｎ−、−Ｎ＝ＣＨ−、−Ｎ＝Ｎ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＨ−、−ＣＨ＝ＣＦ−、−ＣＦ＝ＣＦ−、−Ｃ≡Ｃ−、−ＣＨ＝ＣＨ−ＣＯＯ−、−ＯＣＯ−ＣＨ＝ＣＨ−または単結合を示し、
Ａ^１１、Ａ^１２、Ａ^２１、Ａ^２２、Ａ^３１、Ａ^３２、およびＡ^４１は、各々、同一にまたは異なって、１，４−フェニレンを示し、ここでさらに、１以上のＣＨ基がＮ、１，４−シクロヘキシレンによって置き換えられていてもよく、ここでさらに、１以上の非隣接ＣＨ_２基が−Ｏ−および／または−Ｓ−、１，３−ジオキソラン−４，５−ジイル、１，４−シクロヘキセニレン、１，４−ビシクロ［２，２，２］オクチレン、ピペリジン−１，４−ジイル、ナフタレン−２，６−ジイル、デカヒドロナフタレン−２，６−ジイル、もしくは１，２，３，４−テトラヒドロナフタレン−２，６−ジイルによって置き換えられていてもよく、これら全ての基が非置換であるか、Ｌ^３１によって単置換または多置換されていることが可能であり、
Ｌ^３１は、各々、独立して、または異なって、ハロゲンまたは１〜７個のＣ原子を有するシアノ、ニトロ、アルキル、アルコキシ、アルキルカルボニルもしくはアルコキシカルボニル基であり、ここで１個以上のＨ原子がＦまたはＣｌによって置き換えられていてもよく、
Ｒ^１１、Ｒ^２１、Ｒ^３１およびＲ^４１は、各々、同一にまたは異なって、Ｈ、Ｆ、Ｃｌ、Ｂｒ、Ｉ、ＣＮ、ＳＣＮ、ＯＨ、ＳＦ_５、非置換であっても、Ｆ、Ｃｌ、Ｂｒ、ＩもしくはＣＮによって単置換もしくは多置換されていてもよい２５個までのＣ原子を有する直鎖状もしくは分枝状アルキルであって、それは、１以上の非隣接ＣＨ_２基が各々の場合において互いに独立して−Ｏ−、−Ｓ−、−ＮＨ−、−ＮＲ^０−、−ＣＯ−、−Ｃ（Ｏ）Ｏ−、−ＯＣ（Ｏ）−、−ＯＣ（Ｏ）Ｏ−、−ＳＣ（Ｏ）−、−Ｃ（Ｏ）Ｓ−、−ＣＨ＝ＣＨ−または−Ｃ≡Ｃ−によって−Ｏ−および／または−Ｓ−原子が互いに直接結合されないように置き換えられていることもまた可能である該アルキルを示し、
ｍは、０、１または２であり、
ｍ１、ｍ２は、各々、同一にまたは異なって、０、１、２または３であり、
ｎは、１〜７の整数であり、
ｒ１、ｒ２は、各々、同一にまたは異なって、０、１、２、３、４または５を示し、ならびに
ｓは、０または１を示す。）

(In formula (E3), L ¹¹ , L ²¹ are the same or different, respectively, F, Cl, Br, I, CN, SCN, SF ₅ , F, Cl, Br, even if they are unsubstituted. a straight-chain or branched alkyl having up to 25 C atoms which may be mono- or polysubstituted by I or CN, it may comprise one or more non-adjacent CH ₂ groups with each other in each case Independently, -O-, -S-, -NH-, -NR ^0- , -CO-, -C (O) O-, -OC (O)-, -OC (O) -O-,- It is also possible that SC (O)-, -C (O) S-, -CH = CH- or -C≡C- have replaced the O and / or S atoms so that they do not bond directly to each other. alkyl, or by L ^31, cycloalkyl or aryl having optionally C up to 20 atoms which may be mono- or polysubstituted,
R ⁰ is an alkyl having H or 1 to 4 C atoms.
One of M ¹ and ^{M 2 -Z} 31 ^-A 31 ^- is ^{(Z 32 -A 32) m-} R 31, the other is ^{R 41} or ^{A 41,} or,
Both M ¹ and ^{M 2} are identical or ^different, -Z ³¹ -A ³¹ - or a _{^{(Z 32 -A 32) m -R}} 31, or,
The following formula (E3-1) is the following formula (E3-2) or the following formula (E3-3).
U ¹ and ^{U 2} are each a or the same or _{different, -CH 2 -, - CF 2} -, - O -, - S -, - CO- or -CS- indicates,
V ¹ and V ² represent a single bond or (CH ₂ ) n, respectively, identically or differently, where up to three non-adjacent CH ₂ -groups are replaced by -O- and / or -S-. May be
Z ¹¹ , Z ¹² , Z ²¹ , Z ²² , Z ³¹ and Z ³² are the same or different, respectively, -O-, -S-, -CO-, -COO-, -OCO-, -O-. COO-, ^{-CO-NR 0-} , -NR ^0- CO-, -OCH _2- , -CH ₂ O-, -SCH _2- , -CH ₂ S-, -CF ₂ O-, -OCF _2- , -CF ₂ S-, -SCF _2- , -CH ₂ CH _2- , -CF ₂ CH _2- , -CH ₂ CF _2- , -CF ₂ CF _2- , -CH = N-, -N = CH- , -N = N-, -CH = CH-, -CF = CH-, -CH = CF-, -CF = CF-, -C≡C-, -CH = CH-COO-, -OCO-CH = Indicates CH- or single bond,
A ¹¹ , A ¹² , A ²¹ , A ²² , A ³¹ , A ³² , and A ⁴¹ each exhibit 1,4-phenylene, either identically or differently, where one or more CH groups are N. , may be replaced by 1,4-cyclohexylene, wherein further one or more non-adjacent CH ₂ groups are -O- and / or -S-, 1,3-dioxolane-4,5-diyl, 1,4-Cyclohexenylene, 1,4-bicyclo [2,2,2] octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, or 1 , may be replaced by 2,3,4-tetrahydronaphthalene-2,6-diyl, wherein all groups they are unsubstituted, it is possible which are mono- or polysubstituted by L ³¹ ,
L ³¹ is a cyano, nitro, alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl group, each independently or differently, having a halogen or 1-7 C atoms, wherein one or more H atoms. May be replaced by F or Cl,
R ¹¹ , R ²¹ , R ³¹ and R ⁴¹ are the same or different, respectively, H, F, Cl, Br, I, CN, SCN, OH, SF ₅ , even if not substituted, F, Cl. , Br, I or CN, which is a linear or branched alkyl having up to 25 C atoms which may be mono- or poly-substituted, each of which has one or more non-adjacent CH ₂ groups. In some cases, -O-, -S-, -NH-, -NR ^0- , -CO-, -C (O) O-, -OC (O)-, -OC (O) O-, independently of each other. -SC (O)-, -C (O) S-, -CH = CH- or -C≡C- may replace the -O- and / or -S- atoms so that they are not directly bonded to each other. Also showing the alkyl that is possible,
m is 0, 1 or 2
m1 and m2 are 0, 1, 2 or 3, respectively, the same or different.
n is an integer of 1 to 7 and
r1 and r2 are the same or different, respectively, indicating 0, 1, 2, 3, 4 or 5, and s indicates 0 or 1. )

As the compound represented by the formula (E3), for example, the compounds represented by the following formulas (E3-4) to (E3-13) are preferable.

As the optically active compound, for example, a compound represented by the following formula (E4-1) or formula (E4-2) may be used.

（式（Ｅ４−１）および（Ｅ４−２）中、Ｒ^ｋ１はそれぞれ独立して、水素、ハロゲン、シアノ、−ＳＦ_５、または炭素数１〜５のアルキルであり、このアルキル中の少なくとも１つの−ＣＨ_２−は、−Ｏ−、−ＣＯＯ−または−ＯＣＯ−、で置き換えられてもよく、少なくともひとつの−ＣＨ_２−ＣＨ_２−は、−ＣＨ＝ＣＨ−または−Ｃ≡Ｃ−で置き換えられてもよいが、２つの連続する−ＣＨ_２−が−Ｏ−で置き換えられることはなく、このアルキル中の少なくとも１つの水素はハロゲンで置き換えられてもよく；
Ｒ^ｋ２はそれぞれ独立して水素、ハロゲン、シアノ、−ＳＦ_５、または炭素数１〜２０のアルキルであり、このアルキル中の少なくとも１つの−ＣＨ_２−は、−Ｏ−、−ＣＯＯ−または−ＯＣＯ−、で置き換えられてもよく、少なくともひとつの−ＣＨ_２−ＣＨ_２−は、−ＣＨ＝ＣＨ−または−Ｃ≡Ｃ−で置き換えられてもよいが、２つの連続する−ＣＨ_２−が−Ｏ−で置き換えられることはなく、このアルキル中の少なくとも１つの水素はハロゲンで置き換えられてもよく；
環Ａはそれぞれ独立して、フェニレン環と連結して多環構造を構成する環であり、１，２−フェニレンあるいは１，２−シクロヘキシレンを示し；
環Ａ^ｋ１はそれぞれ独立して２個の結合部位を有する環構造であり、１，４−フェニレン、１，４−シクロヘキシレン、１，３−ジオキサン−２，５−ジイル、テトラヒドロピラン−２，５−ジイル、テトラヒドロピラン−３，５−ジイル、ピリミジン−２，５−ジイル、ピリジン−２，５−ジイル、または１，４−ビシクロ−（２，２，２）−オクチレンであり、これらの環中の少なくとも１つの水素はハロゲンで置き換えられてもよく；
Ｘ^ｋ１はそれぞれ独立して、単結合、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＯＣＨ_２−、−ＣＨ_２Ｏ−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＨ＝ＣＨ−、−ＣＦ_２ＣＦ_２−、−ＣＦ＝ＣＦ−、または−Ｃ≡Ｃ−であり；
Ｙ^ｋ１はそれぞれ独立して、単結合、または−（ＣＨ_２）_n−であり、ｎは１〜２０の整数であり；
Ｚ^ｋ１はそれぞれ独立して、単結合、または炭素数１〜１０のアルキレンであり、このアルキレン中の少なくとも１つの−ＣＨ_２−は、−Ｏ−、−ＣＯＯ−または−ＯＣＯ−、で置き換えられてもよく、少なくともひとつの−ＣＨ_２−ＣＨ_２−は、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられてもよく、このアルキレン中の少なくとも１つの水素はハロゲンで置き換えられてもよく（ただし、Ｚ^ｋ１中に−Ｏ−Ｏ−があるものを除く）；
ｍｋ１はそれぞれ独立して、２〜４の整数であり；
ｎｋ１、およびｎｋ２はそれぞれ独立して、０〜２の整数である。）

(In formulas (E4-1) and (E4-2), R ^k1 is independently hydrogen, halogen, cyano, -SF ₅ , or an alkyl having 1 to 5 carbon atoms, and at least 1 in the alkyl. one of the _-CH 2 - can, -O -, - COO- or -OCO-, in may be replaced, at least one _-CH 2 -CH ₂ - is, -CH = CH- or -C≡C- in Although they may be replaced, the two contiguous −CH _2−s may not be replaced by −O− and at least one hydrogen in this alkyl may be replaced by a halogen;
R ^k2 is each independently hydrogen, halogen, cyano, -SF ₅ , or an alkyl having 1 to 20 carbon atoms, and at least one -CH _2- in this alkyl is -O-, -COO- or-. OCO-, in may be replaced, at least one _-CH 2 -CH ₂ - is, -CH = CH- or may be replaced by -C≡C-, but two consecutive -CH ₂ - is It is not replaced by —O— and at least one hydrogen in this alkyl may be replaced by a halogen;
Ring A is a ring that independently connects with a phenylene ring to form a polycyclic structure, and represents 1,2-phenylene or 1,2-cyclohexylene;
Ring ^Ak1 is a ring structure having two binding sites independently, and is 1,4-phenylene, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, tetrahydropyran-2, These are 5-diyl, tetrahydropyran-3,5-diyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl, or 1,4-bicyclo- (2,2,2) -octylene. At least one hydrogen in the ring may be replaced with a halogen;
X ^k1 is independently single-bonded, -O-, -CO-, -COO-, -OCO-, -OCH _2- , -CH ₂ O-, -CF ₂ O-, -OCF ₂ -,- CH = CH-, -CF ₂ CF _2- , -CF = CF-, or -C≡C-;
Y ^k1 are independently single bonds, or − (CH ₂ ) _n −, and n is an integer from 1 to 20;
Each Z ^k1 is independently a single bond or an alkylene having 1 to 10 carbon atoms, and at least one -CH _2- in this alkylene is replaced with -O-, -COO- or -OCO-. Alternatively, at least one −CH ₂ −CH ₂₋ may be replaced by −CH = CH−, −CF = CF− or −C≡C−, and at least one hydrogen in this alkylene is a halogen. May be replaced with (except for those with -O-O- in ^{Z k1);}
Each mk1 is independently an integer of 2-4;
nk1 and nk2 are independently integers of 0 to 2. )

As the optically active compound, for example, a compound represented by the following formula (E5-1) or formula (E5-2) may be used.

（式（Ｅ５−１）および（Ｅ５−２）中、Ｒ^１、Ｒ^２およびＲ^３は独立して、水素、ハロゲン、シアノ、−ＳＦ_５、または炭素数１から１０のアルキルであり、このアルキルにおいて、少なくとも１つの−ＣＨ_２−は、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ＝ＣＨ−、または−Ｃ≡Ｃ−で置き換えられてもよく、これらの基において、少なくとも１つの水素は、フッ素または塩素で置き換えられてもよく；環Ａ、環Ｂ、環Ｅ、および環Ｆは独立して、５，６，７，８−テトラヒドロナフタレン−１，２−ジイルまたはナフタレン−１，２−ジイルであり；環Ｃ、環Ｄ、および環Ｇは独立して、１，４−シクロヘキシレン、１，４−フェニレン、１，３−ジオキサン−２，５−ジイル、テトラヒドロピラン−２，５−ジイル、テトラヒドロピラン−３，５−ジイル、ピリミジン−２，５−ジイル、ピリジン−２，５−ジイル、または１，４−ビシクロ−（２，２，２）−オクチレンであり、これらの環において、少なくとも１つの水素は、フッ素または塩素で置き換えられてもよく；Ｚ^１、Ｚ^２、Ｚ^３、Ｚ^４、およびＺ^５は独立して、単結合または炭素数１から２０のアルキレンであり、このアルキレンにおいて、少なくとも１つの−ＣＨ_２−は、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ＝ＣＨ−、または−Ｃ≡Ｃ−で置き換えられてもよく、これらの基において、少なくとも１つの水素は、フッ素または塩素で置き換えられてもよく；ａ、ｂ、およびｃは独立して、２、３、または４である。）

(In the formula (E5-1) and ^{(E5-2), R 1, R} 2 and ^{R 3} are independently hydrogen, halogen, cyano, alkyl of -SF _5, or 1 to 10 carbon atoms, this In alkyl, at least one −CH ₂ − may be replaced by −O−, −COO−, −OCO−, −CH = CH−, or −C≡C−, and at least 1 in these groups. One hydrogen may be replaced with fluorine or chlorine; ring A, ring B, ring E, and ring F independently, 5,6,7,8-tetrahydronaphthalene-1,2-diyl or naphthalene-. 1,2-Diyl; Ring C, Ring D, and Ring G are independently 1,4-cyclohexylene, 1,4-phenylene, 1,3-dioxane-2,5-diyl, tetrahydropyran- 2,5-diyl, tetrahydropyran-3,5-diyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl, or 1,4-bicyclo- (2,2,2) -octylene. In these rings, at least one hydrogen may be replaced with fluorine or chlorine; Z ¹ , Z ² , Z ³ , Z ⁴ , and Z ⁵ are independently single-bonded or 1 to 20 carbon atoms. It is an alkylene, in which at least one −CH ₂₋ may be replaced by −O−, −CO−, −COO−, −OCO−, −CH = CH−, or −C≡C−. Well, in these groups, at least one hydrogen may be replaced with fluorine or chlorine; a, b, and c are independently 2, 3, or 4).

As the compound represented by the formula (E5-1), for example, the compound represented by the formula (E5-3) shown below is preferable.
As the compound represented by the formula (E5-2), for example, the compound represented by the following formula (E5-2) is preferable.

As the optically active compound, for example, compounds represented by the following formulas (E6-1) to (E6-7) may be used.

（式（Ｅ６−１）〜（Ｅ６−７）中、Ｒ^Ｋはそれぞれ独立して、炭素数３〜１０のアルキルまたは炭素数３〜１０のアルコキシであり、アルキル中またはアルコキシ中の少なくとも１つの−ＣＨ_２−ＣＨ_２−は、−ＣＨ＝ＣＨ−で置き換えられてもよく；
Ｒ^Ｋ０はそれぞれ独立して、水素または炭素数１〜１０のアルキルであり；
Ａ^Ｋはそれぞれ独立して、芳香族性あるいは非芳香族性の３〜８員環または炭素数９以上の縮合環であり、これらの環の任意の水素がハロゲン、炭素数１〜３のアルキルまたはハロアルキルで置き換えられてもよく、環の−ＣＨ_２−は−Ｏ−、−Ｓ−または−ＮＨ−で置き換えられてもよく、−ＣＨ＝は−Ｎ＝で置き換えられてもよく；
Ｙ^Ｋは独立して、水素、ハロゲン、炭素数１〜３のアルキル、炭素数１〜３のハロアルキル、芳香族性または非芳香族性の３から８員環、または、炭素数９以上の縮合環であり、これらの環の任意の水素がハロゲン、炭素数１〜３のアルキルまたはハロアルキルで置き換えられてもよく、−ＣＨ_２−は−Ｏ−、−Ｓ−または−ＮＨ−で置き換えられてもよく、−ＣＨ＝は−Ｎ＝で置き換えられてもよく；
Ｚ^Ｋは独立して、単結合、炭素数１〜８のアルキレンであるが、任意の−ＣＨ_２−は、−Ｏ−、−Ｓ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＳＯ−、−ＯＣＳ−、−Ｎ＝Ｎ−、−ＣＨ＝Ｎ−、−Ｎ＝ＣＨ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられてもよく、任意の水素はハロゲンで置き換えられてもよく；
Ｘ^Ｋは単結合、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−または−ＣＨ_２ＣＨ_２−であり；
ｍＫは１〜４の整数である。）

(In the formula (E6-1) ~ (E6-7), R K is independently an alkoxy alkyl or 3-10 carbon atoms having 3 to 10 carbon atoms, at least one of the alkyl or a an alkoxy −CH ₂ −CH ₂₋ may be replaced by −CH = CH−;
^{Each RK0} is independently hydrogen or an alkyl having 1 to 10 carbon atoms;
^AK are independently aromatic or non-aromatic 3- to 8-membered rings or condensed rings having 9 or more carbon atoms, and any hydrogen in these rings is a halogen and an alkyl having 1 to 3 carbon atoms. Alternatively, it may be replaced with a haloalkyl, the -CH _{2- of} the ring may be replaced with -O-, -S- or -NH-, and -CH = may be replaced with -N =;
Y ^K is independently hydrogen, halogen, alkyl of 1 to 3 carbon atoms, haloalkyl of 1 to 3 carbon atoms, an aromatic or nonaromatic 3 to 8-membered ring, or having 9 or more fused carbocyclic Rings, any hydrogen in these rings may be replaced with halogen, alkyl or haloalkyl having 1-3 carbon atoms, with -CH _2- being replaced with -O-, -S- or -NH-. Also, -CH = may be replaced by -N =;
Z ^K is independently a single bond, alkylene with 1 to 8 carbon atoms, but any -CH _2- can be -O-, -S-, -COO-, -OCO-, -CSO-,-. It may be replaced by OCS-, -N = N-, -CH = N-, -N = CH-, -CH = CH-, -CF = CF- or -C≡C-, and any hydrogen is a halogen. May be replaced by;
X ^K is single bond, -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- or -CH ₂ CH _2- ;
mK is an integer of 1 to 4. )

As the compound represented by the formula (E6-4), for example, the compound represented by the following formulas (E6-9) and (E6-10) is preferable.
As the compound represented by the formula (E6-6), for example, the compound represented by the following formula (E6-8) is preferable.

As the optically active compound, for example, a compound represented by the following formula (E7) may be used.

（式（Ｅ７）中、Ｌは置換基を有してもよい炭素数１〜１５の連結基を示し、Ｒ¹〜Ｒ¹⁰は、それぞれ独立して、水素原子、又は１価の置換基を示す。）

(In the formula (E7), L represents a linking group having 1 to 15 carbon atoms which may have a substituent, and R ^{1 to} R ¹⁰ each independently have a hydrogen atom or a monovalent substituent. show.)

As the compound represented by the formula (E7), for example, the compound represented by the formula (E7-1) shown below is preferable.

As the optically active compound, for example, a compound represented by the following formula (E8) may be used.

As the optically active compound, for example, a compound represented by the following formula (E9-1) may be used.

（式（Ｅ９−１）において、Ｙ^２は独立して、水素、ハロゲンまたは式（Ｅ９−２）で表される基であり、ただし、Ｙ^２中で少なくとも２つは式（Ｅ９−２）で表される基である。
式（Ｅ９−２）において、Ｒ^１は独立してハロゲン、シアノ、炭素数２〜２０のアルケニルまたは炭素数１〜２０のアルキルであり、この基中の少なくとも１つの−ＣＨ_２−は、−Ｏ−が隣接する場合を除いて−Ｏ−で置き換えられてもよく、この基中の少なくとも１つの水素はハロゲンで置き換えられてもよく；
Ａ^２は独立して、１，４−シクロへキシレン、１，４−フェニレン、４，４’−ビフェニレン、ナフタレン−２，６−ジイル、デカヒドロナフタレン−２，６−ジイル、１，２，３，４−テトラヒドロナフタレン−２，６−ジイルまたは少なくとも１つの水素がハロゲンで置き換えられた１，４−フェニレンであり；
Ｚ^１は独立して、単結合、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ＝ＣＨ−ＣＯＯ−、−ＯＣＯ−ＣＨ＝ＣＨ−、−ＣＨ_２ＣＨ_２−ＣＯＯ−、−ＯＣＯ−ＣＨ_２ＣＨ_２−、−ＯＣＦ_２−または−(ＣＨ_２)_ｐ−であり、−(ＣＨ_２)_ｐ−の１つの−ＣＨ_２−は、−Ｏ−で置き換えられてもよく；
ｐは独立して１〜２０の整数であり；
ｒは独立して１〜３の整数である。）

(In formula (E9-1), Y ² is independently a hydrogen, halogen or group represented by formula (E9-2), provided ^{that at least two of Y 2} are in formula (E9-2). It is a group represented by.
In formula (E9-2), R ¹ is independently a halogen, cyano, an alkenyl having 2 to 20 carbon atoms or an alkyl having 1 to 20 carbon atoms, and at least one −CH ₂ − in this group is − It may be replaced with -O- unless the O- are adjacent; at least one hydrogen in this group may be replaced with a halogen;
A ² is independently 1,4-cyclohexylene, 1,4-phenylene, 4,4'-biphenylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2, 3,4-Tetrahydronaphthalene-2,6-diyl or 1,4-phenylene in which at least one hydrogen is replaced with halogen;
Z ¹ is independent, single bond, -O-, -COO-, -OCO-, -CH = CH-COO-, -OCO-CH = CH-, -CH ₂ CH _{2-COO-, -OCO- CH 2 CH 2 -, - OCF} 2 - or - (CH _{2) p} - in and, - (CH _{2) p} - in one -CH ₂ - may be replaced by -O-;
p is an independently integer from 1 to 20;
r is independently an integer of 1-3. )

As the optically active compound, for example, a compound represented by the following formula (E10-1) may be used.

（式（Ｅ１０−１）中、Ａｒ^２は、炭素数６乃至１２のアリーレン基、炭素数３乃至１２のシクロアルキレン基、又は炭素数３乃至１２のシクロアルケニレン基を表し、ｍは０乃至３である。また、Ｒ^３は、水素、炭素数１乃至１２のアルキル基、又は炭素数１乃至１２のアルコキシ基を表す。また、Ｒ及びＲ^１のうちの一方は、下記式（Ｅ１０−２）で表される置換基を表し、他方は水素を表す。）
（式（Ｅ１０−２）中、Ａｒ^１は、炭素数６乃至１２のアリーレン基、炭素数３乃至１２のシクロアルキレン基、又は炭素数３乃至１２のシクロアルケニレン基を表し、ｋは１乃至３である。また、Ｒ^２は、水素、炭素数１乃至１２のアルキル基、又は炭素数１乃至１２のアルコキシ基を表す。）

(In the formula (E10-1), Ar ² represents an arylene group having 6 to 12 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, or a cycloalkenylene group having 3 to 12 carbon atoms, and m is 0 to 3. Further, R ³ represents hydrogen, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. ^One of R and R 1 represents the following formula (E10-2). ) Represents a substituent, and the other represents hydrogen.)
(In the formula (E10-2), Ar ¹ represents an arylene group having 6 to 12 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, or a cycloalkoxylene group having 3 to 12 carbon atoms, and k represents 1 to 3 carbon atoms. R ² represents hydrogen, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.)

As the compound represented by the formula (E10-1), for example, the compounds represented by the following formulas (E10-3) to (E10-10) are preferable.

As the optically active compound, for example, a compound represented by the following formula (E11) may be used.

（式（Ｅ１１）中、Ｂは、Ｌにより一置換、二置換または三置換されていてもよい１，４−フェニレン、または、１，４−シクロヘキシレンであり、
Ｌは、Ｈ、Ｆ、Ｃｌ、ＣＮ、または、１〜７個の炭素原子を有しハロゲン化されていてもよいアルキル、アルコキシ、アルキルカルボニル、アルコキシカルボニル、アルキルカルボニルオキシまたはアルコキシカルボニルオキシであり、
ｂは、０、１または２であり、
Ｚ^５は、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ２ＣＨ２−または単結合であり、および
Ｒ^５は、１〜１２個の炭素原子を有するアルキル、アルコキシ、アルキルカルボニル、アルコキシカルボニルまたはアルキルカルボニルオキシである。）

(In formula (E11), B is 1,4-phenylene or 1,4-cyclohexylene, which may be mono-substituted, di- or tri-substituted by L.
L is H, F, Cl, CN, or alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 7 carbon atoms and may be halogenated.
b is 0, 1 or 2,
Z ⁵ is -COO-, -OCO-, -CH2CH2- or a single bond, and R ⁵ is an alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkylcarbonyloxy having 1-12 carbon atoms. .. )

As the compound represented by the formula (E11), for example, the compound represented by the formula (E11-1) shown below is preferable.

As the optically active compound, for example, a compound represented by the following formula (E12) may be used.

When a binaphthyl chiral compound is used as the optically active compound, the content of the optically active compound in the first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition is appropriately determined by the intended selective reflection wavelength. can. Specifically, the content of the optically active compound in the first liquid crystal composition 21, the second liquid crystal composition 22, and / or the third liquid crystal composition may be 0.1 to 10% by mass, respectively. It can be made, preferably 1 to 8% by mass.

When the content of the optically active compound in the first liquid crystal composition 21, the second liquid crystal composition 22, and / or the third liquid crystal composition is 0.1% by mass or more, the production scale is used when preparing the optically active compound. Regardless of this, the optically active compound can be easily weighed with high weighing accuracy, and the concentration of the optically active compound tends to be prepared with high accuracy. Therefore, because the concentration of the optically active compound in the first liquid crystal composition 21, the second liquid crystal composition 22, and / or the third liquid crystal composition is not in the desired concentration range, the first cholesteric liquid crystal layer 1 and / or It is possible to prevent the selective reflection wavelength and the temperature dependence of the second cholesteric liquid crystal layer 2 from being out of the predetermined range. Therefore, it is easy to obtain the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2 and / or the third cholesteric liquid crystal layer 3 having a desired spiral twist direction and selective reflection wavelength.
When the content of the optically active compound is 10% by mass or less, the increase in viscosity, the phase transition temperature, and the decrease in storage stability of the first liquid crystal composition 21 and the second liquid crystal composition 22 due to the inclusion of the optically active compound are suppressed. can.

The first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23 do not contain a compound having a structure in which oxygen atoms are bonded to each other, such as a peracid (-CO-OO-) structure, in the molecule. Is preferable.

The first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23 preferably have a high content of a compound having a ring structure in the molecule of all 6 members. The content of the compound in which the ring structure in the molecule is all 6-membered rings is 80% by mass with respect to the total mass of the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23. It is preferably 90% by mass or more, more preferably 95% by mass or more, and substantially only a compound having a 6-membered ring structure in the molecule. Is the most preferable.

In order to suppress deterioration due to oxidation, it is preferable to reduce the content of the compound having a cyclohexenylene group as a ring structure, and the content of the compound having a cyclohexenylene group is set to the first liquid crystal composition 21 and the second. It is preferably 10% by mass or less, preferably 8% by mass or less, and more preferably 5% or less by mass, based on the total mass of the liquid crystal composition 22 and / or the third liquid crystal composition 23. It is preferably 3% by mass or less, and more preferably not substantially contained.

Substantially not contained in the present application means that it is not contained except for an unintentionally contained substance.
When the liquid crystal compound contained in the first liquid crystal composition 21, the second liquid crystal composition 22 and / or the third liquid crystal composition 23 has an alkenyl group as a side chain, or when the alkenyl group is bonded to cyclohexane. The alkenyl group preferably has 2 to 5 carbon atoms. When the alkenyl group is bonded to benzene, the alkenyl group preferably has 4 to 5 carbon atoms, and the unsaturated bond of the alkenyl group and benzene are preferably not directly bonded.

(Additive)
The first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23 may further contain additives, if necessary. For example, a UV absorber, an antioxidant, a hindered amine-based light stabilizer (HALS), or the like can be added for the purpose of enhancing stability against external stimuli. The composition of the additive is not particularly limited, and examples thereof include various compounds known to be added to the liquid crystal composition, such as a benzotriazole-based UV absorber and a hindered phenol-based participation inhibitor. Further, the first liquid crystal composition 21, the second liquid crystal composition 22, and the third liquid crystal composition 23 can further contain various polymerizable compounds for the purpose of immobilizing the cholesteric liquid crystal phase. In this case, the polymerizable compound is preferably a substance that exhibits liquid crystallinity at the stage before curing. By polymerizing and curing a polymerizable compound exhibiting liquid crystallinity by irradiation with ultraviolet rays, heating, or the like, it is possible to form a layer that has no fluidity and has changed to a state in which the orientation form is not changed by an external force.

As described above, according to the present embodiment, in the liquid crystal display device 10, the first cholesteric liquid crystal layer 1 contains two or more kinds of optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero. It contains the first liquid crystal composition 21 and selectively reflects red light. The second cholesteric liquid crystal layer 2 contains a second liquid crystal composition 22 containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects green light. Reflects on. The third cholesteric liquid crystal layer 3 contains a third liquid crystal composition 23 containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects blue light. Reflects on. Then, when the total thickness of the first cholesteric liquid crystal layer 1, the second cholesteric liquid crystal layer 2 and the third cholesteric liquid crystal layer 3 is 100%, the ratio of the thickness of the first cholesteric liquid crystal layer 1 farthest from the display surface is 28. The ratio of the thickness of the second cholesteric liquid crystal layer 2 in the middle is 23 to 39%, and the ratio of the thickness of the third cholesteric liquid crystal layer 3 on the display surface side is 23 to 39%. This makes it possible to provide a liquid crystal display device 10 having a high reflectance of incident light and a high white display quality. In addition, the difference in color due to the difference in the environmental temperature is small, and it is possible to prevent the white display quality from being deteriorated due to the difference in the environmental temperature.

<Second Embodiment>
FIG. 3 is a schematic cross-sectional view for explaining a main part of the liquid crystal display device of the second embodiment. The liquid crystal display device 20 shown in FIG. 3 differs from the liquid crystal display device 10 in that the liquid crystal display device 10 shown in FIG. 1 does not have the transparent adhesive layer 5 and the transparent adhesive layer 6. In the liquid crystal display device 20 shown in FIG. 3, the same members as those of the liquid crystal display device 10 shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 3, in the liquid crystal display device 20 of the present embodiment, the transparent substrate 31a arranged on the second cholesteric liquid crystal layer 2 side of the first cholesteric liquid crystal layer 1 and the first cholesteric of the second cholesteric liquid crystal layer 2 It is in contact with the transparent substrate 32b arranged on the liquid crystal layer 1 side. Further, the transparent substrate 32a arranged on the third cholesteric liquid crystal layer 3 side of the second cholesteric liquid crystal layer 2 and the transparent substrate 33b arranged on the second cholesteric liquid crystal layer 2 side of the third cholesteric liquid crystal layer 3 are in contact with each other. There is. In this case, it is preferable that the transparent substrate 31a and the transparent substrate 32b are in close contact with each other in the in-plane direction of the main surface, and the transparent substrate 32a and the transparent substrate 33b are in the in-plane direction of the main surface. It is preferable that they are in close contact with each other without any gaps.

As described above, one transparent substrate constituting one of the two adjacent cholesteric liquid crystal layers 1, 2, and 3 of the first, second, and third cholesteric liquid crystal layers, and the two adjacent cholesteric liquid crystal layers. Since it is in contact with one transparent substrate constituting the other, it is possible to increase the reflectance of incident light while simplifying the configuration of the liquid crystal display device 20.

<Third Embodiment>
FIG. 4 is a schematic cross-sectional view for explaining a main part of the liquid crystal display device of the third embodiment. The liquid crystal display device 30 shown in FIG. 4 is different in that the liquid crystal display device 20 shown in FIG. 3 does not have the transparent substrate 31a of the first cholesteric liquid crystal layer 1 and the transparent substrate 32a of the second cholesteric liquid crystal layer 1. In the liquid crystal display device 30 shown in FIG. 4, the same members as those of the liquid crystal display device 20 shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 4, in the liquid crystal display device 20 of the present embodiment, one transparent substrate constituting the second cholesteric liquid crystal layer 1 also serves as one transparent substrate constituting the first cholesteric liquid crystal layer 1. One transparent substrate constituting the third cholesteric liquid crystal layer 3 also serves as one transparent substrate constituting the second cholesteric liquid crystal layer 2. That is, the transparent substrate 32b arranged on the first cholesteric liquid crystal layer 1 side of the second cholesteric liquid crystal layer 2 also serves as the transparent substrate arranged on the second cholesteric liquid crystal layer 2 side of the first cholesteric liquid crystal layer 1. Further, the transparent substrate 33b arranged on the second cholesteric liquid crystal layer 2 side of the third cholesteric liquid crystal layer 3 also serves as a transparent substrate arranged on the third cholesteric liquid crystal layer 3 side of the second cholesteric liquid crystal layer 2.

As described above, one transparent substrate constituting one of the two adjacent cholesteric liquid crystal layers 1, 2 and 3 of the first, second and third cholesteric liquid crystal layers 1, 2 and 3 is formed by the two adjacent cholesteric liquid crystal layers. Since it also serves as one transparent substrate constituting the other, it is possible to prevent incident light and reflected light from being refracted or reflected by the interface between the transparent substrates, and while simplifying the configuration of the liquid crystal display device 20. , The reflectance of incident light can be further increased.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to the following examples.
(Liquid crystal compounds other than optically active compounds)
First, the liquid crystal compounds of the following formulas (1) to (16) were mixed at the ratio shown in Table 1 to prepare a liquid crystal compound (first component) other than the optically active compound.
The liquid crystal compounds of the formulas (1) to (9) are dielectrically positive liquid crystal compounds.
The liquid crystal compounds of the formulas (10) to (16) are dielectrically neutral liquid crystal compounds.

Regarding the obtained liquid crystal compound (first component) other than the optically active compound, the phase transition temperature ( _TNI ), which is the temperature at which the liquid crystal phase is transferred to the isotropic phase, and the melting point, which is the temperature at which the liquid crystal compound (first component) is restored from the solid phase to the liquid crystal phase. And the refractive index anisotropy (Δn) at a temperature of 25 ° C. and a wavelength of 589 nm, the dielectric anisotropy (Δε) at a temperature of 25 ° C. and a frequency of 1 kHz, and the viscosity (η) which is the flow viscosity at a temperature of 20 ° C. ) And were measured respectively. The results are shown in Table 2. Although the compositions of the three types of first components corresponding to the cholesteric liquid crystal compositions 1 to 3 are different, all of them show the physical property values shown in Table 2.

The obtained first component has a high phase transition temperature ( _TNI ), a low melting point, a large dielectric anisotropy (Δε), and a small viscosity (η), so that the operating temperature range is wide and the voltage is low. It turned out that it can be driven.

(Cholesteric liquid crystal layers 1 to 3)
Next, two types of chiral compounds (second components), which are optically active compounds, were added to each of the obtained three types of first components at the ratios shown in Table 1, and the selective reflection wavelength at 25 ° C. was 470 nm, respectively. Cholesteric liquid crystal compositions 1 to 3 adjusted to be about 560 nm and 630 nm were prepared.
Then, the cholesteric liquid crystal compositions 1 to 3 composed of the first component and the second component are injected into a cell having a gap of 3 μm having an electrode with a homogeneous alignment film, and then heated to a temperature _{equal to or higher than the phase transition temperature TNI.} , Slowly cooled to room temperature. Then, by pressing the cell surface with a finger, cholesteric liquid crystal layers 1 to 3 having a thickness of 3 μm were produced. The temperature dependence of the selective reflection wavelengths of the produced cholesteric liquid crystal layers 1 to 3 was measured. The results are shown in Table 3.

"Temperature dependence of selective reflection wavelength (0 to 50 ° C)"
Light is incident on the cholesteric liquid crystal layer at an incident angle of 30 ° from the normal of the panel, and the wavelength of the light reflected in the normal direction of the liquid crystal panel at each temperature of 0 ° C, 25 ° C, and 50 ° C is set to the liquid crystal display. Measurement was performed using a panel evaluation device (trade name; LCD-5200 (manufactured by Otsuka Electronics Co., Ltd.)), and the selective reflection wavelength at each temperature was determined. Then, by dividing the difference between the maximum value and the minimum value of the selective reflected light in the temperature range of 0 to 50 ° C. by the temperature range (50 ° C.), the temperature depends on the selective reflection wavelength in the temperature range of 0 to 50 ° C. The sex was calculated.

From the results in Table 3, all of the cholesteric liquid crystal layers 1 to 3 having the cholesteric liquid crystal compositions 1 to 3 composed of the first component and the second component have selective reflection wavelengths (0 ° C., 25 ° C. and 50 ° C.). It can be seen that the temperature dependence is small. It can be seen that the cholesteric liquid crystal layers 1 to 3 are suitable as a cholesteric material for a liquid crystal display device.
Further, when the temperature of the cholesteric liquid crystal layers 1 to 3 having the cholesteric liquid crystal compositions 1 to 3 was changed from 0 ° C. to 50 ° C. and the change in color was visually observed, any of the colors of blue, green and red was observed. There was no change in. Therefore, it is presumed that there is no change in color due to the change in the environmental temperature in any of the cholesteric liquid crystal layers 1 to 3, and the deterioration of the white display quality due to the difference in the environmental temperature in the liquid crystal display device is prevented. Will be done.

Next, in the same manner as described above, the cholesteric liquid crystal compositions 1 to 3 composed of the first component and the second component are injected into a cell having a glass substrate with a homogeneous alignment film and having a gap of 4 μm, and the thickness is 4 μm. Cholesteric liquid crystal layers 4 to 6 were prepared. Further, the cholesteric liquid crystal compositions 1 to 3 composed of the first component and the second component are injected into a cell having an electrode with a homogeneous alignment film and having a gap of 5 μm to prepare cholesteric liquid crystal layers 7 to 9 having a thickness of 5 μm. did. Further, the cholesteric liquid crystal composition 3 composed of the first component and the second component was injected into a cell having a gap of 6 μm having an electrode with a homogeneous alignment film to prepare a cholesteric liquid crystal layer 10 having a thickness of 6 μm.

(Example 1)
As Example 1, each layer of the cholesteric liquid crystal layer 4 having a thickness of 4 μm (B), the cholesteric liquid crystal layer 5 having a thickness of 4 μm (G), and the cholesteric liquid crystal layer 9 having a thickness of 5 μm (R) is filled with silicone oil, and is shown in Table 4. A liquid crystal display in which three layers are laminated so that the thickness is 4 μm (B), 4 μm (G), and 5 μm (R) in order from the display surface side, and the thickness ratio of each liquid crystal layer is as shown in Table 4. Obtained the device. The reflectance, chromaticity x, and chromaticity y of the obtained liquid crystal display device of Example 1 were measured.

The ratio of the thickness of each cholesteric liquid crystal layer was obtained by rounding off the first decimal place of the percentage of the thickness of each cholesteric liquid crystal layer to the total thickness of the three layers. A liquid crystal panel evaluation device (trade name; LCD-5200 (trade name; LCD-5200) (trade name: LCD-5200) (trade name: LCD-5200) The reflectance was determined using (Otsuka Electronics Co., Ltd.)). At this time, the reflectance of the standard white plate was set to 100%. Further, L in the table represents the distance from the point (x = 0.33, y = 0.33) in the chromaticity diagram, and L = ((x −0.33) ² + (y−0.33). ) ² ) ^{It is represented by 1/2} , and the smaller the value of L, the more the white state without color.

(Comparative Examples 1-2)
Similarly, the liquid crystal display devices of Comparative Examples 1 to 6 obtained by laminating three cholesteric liquid crystal layers having the thickness and the thickness ratio shown in Table 4 in the order shown in the same table were produced, and the obtained Comparative Examples 1 to 6 were produced. The reflectance, chromaticity x, and chromaticity y of the liquid crystal display device of No. 2 were measured. The results are shown in Table 4.

From the results in Table 4, in the liquid crystal display device of Example 1, the ratio of the thickness of B / G / R was 31% / 31% / 38%, and the value of the layer L on the display surface side was 0.0083. rice field. On the other hand, in the liquid crystal display devices of Comparative Examples 1 and 2, the L values were 0.0206 and 0.0160, respectively. Therefore, it was found that in Example 1, the value of L was the smallest and the color closest to white was exhibited as compared with Comparative Examples 1 and 2.

(Example 2)
As Example 2, the layers of the cholesteric liquid crystal layer 1 having a thickness of 3 μm (B), the cholesteric liquid crystal layer 5 having a thickness of 4 μm (G), and the cholesteric liquid crystal layer 9 having a thickness of 5 μm (R) are filled with silicone oil and shown in Table 5. A liquid crystal display in which three layers are laminated so that the thickness is 3 μm (B), 4 μm (G), and 5 μm (R) in order from the display surface side, and the thickness ratio of each liquid crystal layer is as shown in Table 5. Obtained the device. The reflectance, chromaticity x, and chromaticity y of the obtained liquid crystal display device of Example 2 were measured.

(Comparative Examples 3 to 6)
Further, in the same manner, the liquid crystal display devices of Comparative Examples 3 to 6 obtained by laminating three cholesteric liquid crystal layers having the thickness and the thickness ratio shown in Table 5 in the order shown in the same table were produced, and the obtained Comparative Example. The reflectance, chromaticity x, and chromaticity y of the liquid crystal display devices 3 to 6 were measured. In Comparative Examples 3 to 6, the cholesteric liquid crystal layers 1, 5 and 9 used in Example 2 were laminated in a different order from that in Example 2. The results are shown in Table 5.

From the results in Table 5, in the liquid crystal display device of Example 2, the ratio of the thickness of B / G / R was 25% / 33% / 42%, and the value of L was 0.0131. Further, in the liquid crystal display devices of Comparative Examples 3 to 6, the values of L were 0.0085, 0.0289, 0.0171, and 0.0376, respectively. Therefore, in Example 2, it was found that the value of L was the smallest and the color closest to white was exhibited as compared with Comparative Examples 3 to 6. Further, in Example 2, although the value of L was larger than that of Comparative Example 3, the reflectance was the second largest after Comparative Example 4. Therefore, it was found that Example 2 is a liquid crystal display device in which the reflectance and the white display quality are well-balanced.

(Example 3)
As Example 3, each layer of the cholesteric liquid crystal layer 7 having a thickness of 5 μm (B), the cholesteric liquid crystal layer 2 having a thickness of 3 μm (G), and the cholesteric liquid crystal layer 9 having a thickness of 5 μm (R) is filled with silicone oil, and is shown in Table 6. A liquid crystal display in which three layers are laminated so that the thickness is 5 μm (B), 3 μm (G), and 5 μm (R) in order from the display surface side, and the thickness ratio of each liquid crystal layer is as shown in Table 6. Obtained the device.

(Example 4)
As Example 4, each layer of the cholesteric liquid crystal layer 7 having a thickness of 5 μm (B), the cholesteric liquid crystal layer 5 having a thickness of 4 μm (G), and the cholesteric liquid crystal layer 9 having a thickness of 5 μm (R) is filled with silicone oil, and is shown in Table 6. A liquid crystal display in which three layers are laminated so that the thickness is 5 μm (B), 4 μm (G), and 5 μm (R) in order from the display surface side, and the thickness ratio of each liquid crystal layer is as shown in Table 6. Obtained the device.
In Examples 3 to 4, the stacking order of the three layers is the same as in Example 2 (B / G / R from the display surface side), and the thickness (B) of the layer on the display surface side is from the intermediate layer (G). Also thickened. The reflectance, chromaticity x, and chromaticity y of the obtained liquid crystal display devices of Examples 3 to 4 were measured. The results are shown in Table 6.

From the results in Table 6, in the liquid crystal display device of Example 3, the ratio of the thickness of B / G / R was 38% / 23% / 38%, and the value of L was 0.0063. Therefore, it was found that the value of L was the smallest and the color closest to white was exhibited as compared with Comparative Examples 1 to 6. Further, as compared with Examples 1 and 2, it was found that the reflectance was the largest and the L value was the smallest, and the reflectance and the white display quality were the best.
Further, in the liquid crystal display device of Example 4, the ratio of the thickness of B / G / R was 36% / 29% / 36%, the reflectance was 53.0%, and the value of L was 0.0118. .. Therefore, as compared with Comparative Examples 1 to 6, the reflectance is the second largest after Comparative Examples 4 and 1, and the L value is the second smallest after Comparative Example 3, and the balance between the reflectance and the white display quality is balanced. It turned out that it was a liquid crystal display device.

(Example 5)
The cholesteric liquid crystal layer 1, the cholesteric liquid crystal layer 5, and the cholesteric liquid crystal layer 9 of Example 2 were bonded together using an adhesive (trade name: LUMISIL203UV; manufactured by Asahi Kasei Wacker Silicone Co., Ltd.), and the refractive index at 25 ° C. was 1.41. A liquid crystal display device of Example 5 in which a cholesteric liquid crystal layer 1, a cholesteric liquid crystal layer 5, and a cholesteric liquid crystal layer 9 were laminated via a transparent adhesive layer having a thickness of about 100 μm was obtained.

With respect to the obtained liquid crystal display device, the pixel electrode of the cholesteric liquid crystal layer 1, the pixel electrode of the cholesteric liquid crystal layer 5, and the pixel electrode of the cholesteric liquid crystal layer 9 are measured by a method of measuring the pixel deviation using an optical microscope manufactured by Olympus Corporation. The vertical and horizontal misalignments in the plan view were measured, and the total of the vertical misalignment and the horizontal misalignment was calculated. As a result, the misalignment of the two adjacent pixel electrodes was about 45 μm, respectively.

(Example 6)
Examples are different from Example 5 except that the pixel electrodes of the cholesteric liquid crystal layer 1, the pixel electrodes of the cholesteric liquid crystal layer 5, and the pixel electrodes of the cholesteric liquid crystal layer 9 are laminated so as to have a larger displacement in a plan view. The liquid crystal display device of Example 6 was obtained in the same manner as in 5.
For the obtained liquid crystal display device, the total of the vertical misalignment and the horizontal misalignment was calculated in the same manner as in Example 5. As a result, the misalignment of the two adjacent pixel electrodes was 90 μm, respectively.

Characters were displayed on the liquid crystal display devices of Examples 5 and 6 thus obtained, and the display surface was visually observed. As a result, in Example 5, a brighter and whiter display was obtained as compared with Example 6.

1 1st cholesteric liquid crystal layer 2 2nd cholesteric liquid crystal layer 3 3rd cholesteric liquid crystal layer 5 transparent adhesive layer 6 transparent adhesive layer 7 light absorption layer 10 liquid crystal display device 20 liquid crystal display device 30 liquid crystal display device 21 1st cholesteric liquid crystal composition ( 1st liquid crystal composition)
22 Second cholesteric liquid crystal composition (second liquid crystal composition)
23 Third cholesteric liquid crystal composition (third liquid crystal composition)
31a Transparent substrate 31b Transparent substrate 32a Transparent substrate 32b Transparent substrate 33a Transparent substrate 33b Transparent substrate 41a Common electrode 42a Common electrode 43a Common electrode 41b Pixel electrode 42b Pixel electrode 43b Pixel electrode

Claims (12)

It is provided with a first cholesteric liquid crystal layer, a second cholesteric liquid crystal layer, and a third cholesteric liquid crystal layer laminated on each other.
The first cholesteric liquid crystal layer contains a first cholesteric liquid crystal composition containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects red light. Reflected on
The second cholesteric liquid crystal layer contains a second cholesteric liquid crystal composition containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects green light. Reflected on
The third cholesteric liquid crystal layer contains a third cholesteric liquid crystal composition containing two or more optically active compounds selected so that the temperature dependence of the selective reflection wavelength becomes zero, and selectively selects blue light. Reflected on
When the total thickness of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer is 100%, the ratio of the thickness of the layer farthest from the display surface is 28 to 48%, which is intermediate. A liquid crystal display device in which the ratio of the thickness of the layer is 23 to 39% and the ratio of the thickness of the layer on the display surface side is 23 to 39%. Of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer, the thickness of the layer farthest from the display surface is larger than the thickness of the intermediate layer, and the thickness of the intermediate layer is displayed. The liquid crystal display device according to claim 1, which is larger than the thickness of the layer on the surface side. Of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer, the thickness of the intermediate layer is larger than the thickness of the layer farthest from the display surface and the thickness of the layer on the display surface side. The small liquid crystal display device according to claim 1. Claims 1 to 3 that the first cholesteric liquid crystal layer is the layer farthest from the display surface, the second cholesteric liquid crystal layer is an intermediate layer, and the third cholesteric liquid crystal layer is a layer on the display surface side. The liquid crystal display device according to any one item. Of the first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer, the spiral twist direction of the cholesteric liquid crystal composition forming the layer farthest from the display surface constitutes the layer on the display surface side. The liquid crystal display device according to any one of claims 1 to 4, which is the same as the spiral twisting direction of the cholesteric liquid crystal composition and opposite to the spiral twisting direction of the cholesteric liquid crystal composition constituting the intermediate layer. .. Any of claims 1 to 5, wherein at least one of the optically active compounds contained in the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition is a binaphthyl chiral compound. The liquid crystal display device according to item 1. Any one of claims 1 to 6, wherein at least one of the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition contains a dielectrically positive liquid crystal compound. The liquid crystal display device according to. Any one of claims 1 to 7, wherein at least one of the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition contains a dielectrically neutral liquid crystal compound. The liquid crystal display device according to the section. The first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer are each of the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition between two transparent substrates facing each other. Cholesteric liquid crystal composition is sandwiched,
The transparent substrate constituting one of the two adjacent cholesteric liquid crystal layers of the first, second and third cholesteric liquid crystal layers and the transparent substrate constituting the other of the two cholesteric liquid crystal layers are transparently adhered to each other. Layered,
The liquid crystal display device according to claim 1, wherein the difference in refractive index between the transparent adhesive layer and the transparent substrate in contact with the transparent adhesive layer at 25 ° C. is 0.12 or less. The first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer are each of the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition between two transparent substrates facing each other. Cholesteric liquid crystal composition is sandwiched,
One transparent substrate constituting one of two adjacent cholesteric liquid crystal layers among the first, second, and third cholesteric liquid crystal layers, and one transparent substrate constituting the other of the two adjacent cholesteric liquid crystal layers. The liquid crystal display device according to claim 1, which is in contact with the liquid crystal display device. The first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer are each of the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition between two transparent substrates facing each other. Cholesteric liquid crystal composition is sandwiched,
One transparent substrate constituting one of the two adjacent cholesteric liquid crystal layers of the first, second, and third cholesteric liquid crystal layers constitutes the other of the two adjacent cholesteric liquid crystal layers. The liquid crystal display device according to claim 1, which also serves as. The first cholesteric liquid crystal layer, the second cholesteric liquid crystal layer, and the third cholesteric liquid crystal layer are surfaces on the side in contact with the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition, respectively. A common electrode is provided on a surface of the pixel electrode substrate made of a transparent substrate provided with a pixel electrode, and a surface in contact with the first cholesteric liquid crystal composition, the second cholesteric liquid crystal composition, and the third cholesteric liquid crystal composition. The cholesteric liquid crystal composition is sandwiched between the common electrode substrate and the transparent substrate.
Two adjacent pixel electrodes of the three pixel electrodes constituting the first, second, and third cholesteric liquid crystal layers have a misalignment dx in the first direction in a plan view and are orthogonal to the first direction. The liquid crystal display device according to any one of claims 9 to 11, which is arranged so that the total (dx + dy) with the misalignment dy in the two directions is 60 μm or less.

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