JP2002116461A - Liquid crystal optical modulation device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal optical modulation device which is bright with preferable contrast and color purity and excellent in bistable property. SOLUTION: The liquid crystal optical modulation device has a liquid crystal layer 10 containing a liquid crystal material 6 having the following properties held between a pair of substrates. The liquid crystal material shows a cholesteric phase at room temperature and has the peak of selective reflection wavelength in the visible wavelength region. In the liquid crystal layer 10 in the selective reflection state, the liquid crystal domain in the pixel region X in at least one substrate proximity region 1a of the substrate proximity regions 1a, 2a near the substrates has a mixture state of polydomains and monodomains.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal light modulation device and a method for manufacturing the same.

[0002]

2. Description of the Related Art A liquid crystal light modulator basically has a liquid crystal layer containing a liquid crystal material sandwiched between a pair of substrates. The arrangement of liquid crystal molecules in the liquid crystal layer is controlled by applying a predetermined drive voltage to the liquid crystal layer, and external light incident on the liquid crystal light modulation element is modulated to display a target image.

As such a liquid crystal light modulation device, a liquid crystal light modulation device using cholesteric liquid crystal is known, and various studies have been made.

The cholesteric liquid crystal includes a liquid crystal which itself exhibits a cholesteric phase and a chiral nematic liquid crystal obtained by adding a chiral agent to a nematic liquid crystal.

Such a cholesteric liquid crystal has a feature that liquid crystal molecules form a helical structure. After being held between a pair of substrates, an external stimulus such as an electric field, a magnetic field, and a temperature is applied to the liquid crystal. Then, three states called a planar state, a focal conic state, and a homeotropic state are shown.

In a liquid crystal light modulation element (for example, a liquid crystal display element) using a cholesteric liquid crystal, these three states are as follows.
Since the light transmittance and the reflectivity are different from each other, the display can be performed by appropriately selecting the three states and the external stimulus applying method. Examples of the display include a display of a cholesteric-nematic phase transition mode using a homeotropic state and a focal conic state, and a display of a bistable mode using a planar state and a focal conic state.

Above all, the display in the bistable mode is characterized in that the planar state and the focal conic state are stable even when no external stimulus is applied, that is, the display state is maintained even when no external stimulus is applied (for example, when no voltage is applied). It has bistability (memory characteristics) that it is maintained. For this reason, a liquid crystal light modulation element using cholesteric liquid crystal has been actively studied in recent years as a memory element (a display element having a stable display state).

In particular, a reflection type liquid crystal light modulator using a cholesteric liquid crystal having a selective reflection characteristic in a visible region in a planar state has a memory property and a bright reflection state can be obtained. , Because bright display is possible without using color filters,
As a display element which is very effective in reducing power consumption, application to a power-saving display element such as a display element of a portable information device is expected.

Here, the bistability means that the helical axis of the cholesteric liquid crystal is in a state substantially perpendicular to the substrate surface and is in a planar arrangement state (a planar state) indicating a selective reflection state, and the helical axis of the liquid crystal is substantially perpendicular to the substrate surface. It means that it is stable in two states of a focal conic arrangement state (a focal conic state) which is in a parallel state and transmits visible light.

[0010]

However, since the liquid crystal display device utilizing the selective reflection characteristic of the cholesteric liquid crystal employs a reflection system based on light interference, the reflection wavelength shifts to the short wavelength side according to the incident angle and observation angle of light. Have the problem of shifting.

This problem becomes more conspicuous as the helical axis of the cholesteric liquid crystal in the planar arrangement is closer to the vertical with respect to the substrate surface. In particular, in the case of a TN liquid crystal element or an STN liquid crystal element, when a liquid crystal layer is sandwiched between a pair of substrates formed by rubbing a generally used polyimide thin film, the helical axis of the cholesteric liquid crystal is It becomes completely or almost completely perpendicular to the surface, and the viewing angle becomes very narrow. As a result, when this liquid crystal element is used as a display element, visibility is significantly reduced.

Further, it is difficult to maintain the focal conic state due to an increase in the regulating force at the polyimide interface due to the rubbing of the rubbed polyimide thin film, and as a result, the bistability characteristic of the cholesteric liquid crystal element may be lost. .

Attempts have been made to avoid this phenomenon by making the cholesteric liquid crystal spiral axis slightly inclined with respect to the substrate normal. One is PSCT (Polymer St) which disperses a polymer material in cholesteric liquid crystal.
available Cholesteric Text
ure), in which the direction of the helical axis is made random by the interaction at the polymer-liquid crystal interface (see Japanese Patent Application Laid-Open No. 6-507505). However, in this method, a polymer is mixed in the liquid crystal material, which may cause a decrease in device reliability and an increase in driving voltage.

As another method, there is a method in which a polyimide film not intentionally subjected to a rubbing process is formed on the substrate surface facing the liquid crystal and the angle of the spiral axis is inclined. But,
In this method, regions (domains) having different helical axis inclination directions (projection directions to the substrate) are randomly formed, so that incident light is easily scattered due to a difference in the refractive index between the domains, and display during selective reflection is performed. The color purity is reduced. Also,
In the case of a multi-layer liquid crystal display device in which multicoloring is attempted by using a multi-layer structure, the reflected light of the lower layer is easily affected by the light scattering of the upper layer, and both the contrast and the color purity are reduced.

In order to improve the characteristics of a cholesteric liquid crystal element in which a liquid crystal is sandwiched between substrates on which the non-alignment-treated polyimide film is formed, Japanese Patent Application Laid-Open No. 10-31205 discloses that
The surface treatment method of the polyimide film is different between the polyimide film formed on the substrate on the observation side and the polyimide film formed on the substrate on the non-observation side (opposite side to the observation side). Is rubbed to make the non-observation side liquid crystal domains non-aligned random domains (poly domains), and the helical axis of the non-observation side liquid crystal is almost completely perpendicular to the substrate surface to make the non-observation side liquid crystal domains uniform. (Mono-domain conversion) has been proposed. However, in this method, the rubbing treatment is applied to the entire polyimide film on the non-observation side substrate, so that the liquid crystal domain becomes monodomain over the entire substrate, and as a result, the stability in the focal conic state tends to decrease, and the characteristics of the cholesteric liquid crystal element , The bistability characteristic is degraded. Further, even in the planar alignment state, the inclination of the helical axis of the liquid crystal on the random domain side tends to be gradually lost, and the long-term bistability is lacking. In any case, it is difficult to maintain the display state (good display image state with high contrast and color purity) for a long time when no voltage is applied, and it is difficult to achieve both high contrast and high color purity characteristics and bistability. Have difficulty.

Further, the cholesteric liquid crystal focal
Regarding the conic state, the focal conic state is a state in which the helical axis of the liquid crystal molecules is oriented in the substrate plane direction. Normally, liquid crystal is divided into a plurality of liquid crystal molecule regions (liquid crystal domains). In the focal conic state, the direction of the helical axis of the liquid crystal in each liquid crystal domain is the same or substantially the same, but as shown in FIG. 21, the direction F of the helical axis of the liquid crystal molecule is different between adjacent liquid crystal domains. .
Therefore, the light incident on the liquid crystal element is scattered by a small amount due to the refractive index difference at the interface between the liquid crystal domains. In particular, when the helical pitch is small (in other words, when the helical pitch is small enough to show selective reflection in the visible region in the planar state).
However, in principle, the liquid crystal domain also becomes small, and light scattering in the device becomes large, and when applied to a display device, there arises a problem that the contrast is reduced.

In addition, an element in which a plurality of liquid crystal layers are laminated (laminated liquid crystal element), for example, by laminating a plurality of liquid crystal layers having different selective reflection wavelengths, two or more colors can be displayed (for example, full-color display). It is known that a laminated liquid crystal light modulation element can be obtained. In the case of an element having such a laminated structure, the influence of the inter-domain scattering becomes particularly large due to multiple scattering between the liquid crystal layers and the like, and the contrast tends to deteriorate.

Accordingly, the present invention provides a liquid crystal light modulation device comprising a pair of substrates, which sandwich a liquid crystal layer containing a liquid crystal material exhibiting a cholesteric phase at room temperature and having a selective reflection wavelength peak in a visible wavelength region. It is an object to provide a liquid crystal light modulation element which is bright, has good contrast and color purity, and has excellent bistability.

The present invention also relates to a multi-layer liquid crystal display device in which a plurality of liquid crystal layers each sandwiched between a pair of substrates are laminated, which is bright, has good contrast and color purity, and has good bistability. An object of the present invention is to provide an excellent laminated liquid crystal light modulation element.

The present invention also relates to a method of manufacturing a liquid crystal light modulation element comprising a liquid crystal layer containing a liquid crystal material exhibiting a cholesteric phase at room temperature between a pair of substrates and having a selective reflection wavelength peak in a visible wavelength region. Accordingly, it is an object of the present invention to provide a method for manufacturing a liquid crystal light modulation element that can obtain a liquid crystal light modulation element that is bright, has good contrast and color purity, and has excellent bistability.

[0021]

Means for Solving the Problems The inventor of the present invention has conducted various studies to solve the above problems, and has found the following.

That is, in a liquid crystal light modulation element in which a liquid crystal layer containing a liquid crystal material which exhibits a cholesteric phase at room temperature and has a selective reflection wavelength peak in a visible wavelength region is sandwiched between a pair of substrates, When the liquid crystal layer in the pixel region near at least one of the substrates facing the two substrates is in a mixed state of a poly domain and a mono domain, or the two substrates of the liquid crystal layer are in a selective reflection state. When each of the liquid crystal domains in the pixel region near the substrate has a polydomain structure, and the liquid crystal domains in the pixel regions near both substrates have different angles to the substrate normal of the cholesteric spiral axis of the liquid crystal, the element observation side Reflected light can be collected in the front, and a bright, high-contrast, high-color-quality image can be displayed. Furthermore, it has been found that a display state (a good image state with high brightness, contrast and high color purity) can be maintained for a long time when no external stimulus is applied (for example, when no voltage is applied).

Here, the "polydomain" means that in the selective reflection state of the liquid crystal, the helical axis of the liquid crystal slightly tilts from the substrate normal,
The "monodomain" is a region in which the direction of projection of the helical axis onto the substrate is randomly different, and the "monodomain" is a region in which the helical axis of the liquid crystal is equalized perpendicularly or substantially perpendicularly to the substrate surface.

The present invention is based on this finding,
In order to solve the above problems, the following first and second liquid crystal light modulation elements are provided. (1) First liquid crystal light modulation element: exhibits a cholesteric phase between a pair of substrates at room temperature, and
In a liquid crystal light modulation element sandwiching a liquid crystal layer containing a liquid crystal material having a selective reflection wavelength peak in a visible wavelength region, in the selective reflection state, the liquid crystal layer in the vicinity of at least one of the substrates near the two substrates. A liquid crystal light modulation device, wherein a liquid crystal domain in a pixel region is a mixed state of a poly domain and a mono domain. (2) The second liquid crystal light modulation element exhibits a cholesteric phase between a pair of substrates at room temperature, and
In a liquid crystal light modulation element sandwiching a liquid crystal layer containing a liquid crystal material having a selective reflection wavelength peak in a visible wavelength region, each liquid crystal domain in a pixel region near a substrate facing both substrates of the liquid crystal layer in a selective reflection state is any A liquid crystal light modulation element, which has a polydomain structure, and in which the angle formed by the cholesteric helical axis of the liquid crystal with the substrate normal differs between the liquid crystal domains in the pixel regions near the two substrates.

In each of the first and second liquid crystal light modulation devices, at least one of the pair of substrates is usually a transparent substrate, and the substrate on the device observation side is usually a transparent substrate.

The term "polydomain" as used in the present invention refers to a region in which the liquid crystal helical axis is slightly inclined from the substrate normal in the liquid crystal selective reflection state, and the direction of projection of the helical axis onto the substrate is randomly different. The term “monodomain” refers to a region where the helical axis of the liquid crystal is equalized perpendicular to or substantially perpendicular to the substrate surface.

According to the first and second liquid crystal light modulating elements of the present invention, in the first liquid crystal light modulating element, at least one of the liquid crystal layers in the selective reflection state near at least one of the substrates facing the two substrates. Since the liquid crystal domains in the nearby pixel region are in a mixed state of the poly domain and the mono domain, the second liquid crystal light modulation element has a selective reflection state in the pixel region near the substrate facing the two substrates of the liquid crystal layer. Each liquid crystal domain has a polydomain structure, and the angle between the cholesteric helical axis of the liquid crystal and the substrate normal is different between the liquid crystal domains in the pixel regions near both substrates (that is, in the image region near one substrate). The angle between the helical axis of the liquid crystal domain and the substrate normal is smaller than that in the pixel region near the other substrate)
A good image with high brightness, high contrast, and high color purity can be displayed, and a display state (a good image state with high brightness, high contrast, high color purity) can be maintained for a long time, for example, when no voltage is applied. In other words, high reflection intensity, high contrast,
High color purity characteristics and bistability can both be achieved.

In the first and second liquid crystal light modulation elements according to the present invention, electrodes (for example, pixel electrodes) may be formed on the pair of substrates as needed.

In the first liquid crystal light modulation device according to the present invention,
In the selective reflection state, each of the liquid crystal domains in the pixel regions near both substrates may be in the mixed state, or one of the liquid crystal domains in the pixel regions near both substrates may be in the mixed state. Yes, the other liquid crystal domain may be composed of only the poly domain.

In the selective reflection state, when all the liquid crystal domains in the pixel regions near the two substrates are in the mixed state, the ratio of the poly domain and the mono domain mixed between the liquid crystal domains in the pixel region near the two substrates is reduced. Preferably they are different. More preferably, the liquid crystal domain having a higher polydomain ratio among the liquid crystal domains in the pixel regions near the two substrates is a liquid crystal domain in the pixel region near the substrate on the element observation side.

In the selective reflection state, when one of the liquid crystal domains in the pixel regions near the two substrates is in the mixed state and the other liquid crystal domain is composed of only the poly domains, only the poly domains are used. It is preferable that the constituted liquid crystal domain is a liquid crystal domain in a pixel region near the substrate on the element observation side.

In any case, in the first liquid crystal light modulating element according to the present invention, at least the side of the pair of substrates facing the liquid crystal domain of the substrate facing the mixed liquid crystal domain is aligned with the liquid crystal. A control layer is provided,
The alignment of the liquid crystal molecules in the mixed state may be controlled by the alignment control layer. As the orientation control, the following (a)
And (b). (A) The case where the alignment control is performed by rubbing the alignment control layer provided on the substrate facing the liquid crystal domains in the mixed state. In this case, it is preferable that the rubbed density of the rubbed orientation control layer is 10 or less. The mixed state may be realized by partially rubbing the orientation control layer, for example, by performing rubbing through a mask having a predetermined pattern of openings.

The direction of rubbing is not particularly limited, and the rubbing may be performed in any direction. For example, when a strip-shaped electrode is provided on the substrate, the direction may be along the electrode direction or may be a direction crossing the electrode direction. However, when rubbing the entire orientation control layer, the rubbing direction is set to one direction. (B) The case where the alignment control is performed by irradiating the alignment control layer provided on the substrate facing the mixed liquid crystal domains with predetermined light. In this case, the alignment control may be determined by an irradiation amount of the predetermined light to the alignment control layer, or may be determined by a substrate temperature at the time of irradiation of the predetermined light to the alignment control layer. Alternatively, it may be determined by a light irradiation angle with respect to a substrate surface when the predetermined light is irradiated on the alignment control layer. The mixed state may be realized by partially irradiating the alignment control layer with light, for example, by irradiating light through a mask having a predetermined pattern of openings. In any case, the predetermined light can be exemplified by ultraviolet light.

When monodomains and polydomains coexist, the angle of the liquid crystal helical axis to the substrate is preferably greater than zero and 10 ° or less on average, more preferably 3 ° or more and 8 ° or less.

In the second liquid crystal light modulation device according to the present invention,
In the selective reflection state, of the liquid crystal domains in the pixel regions near the two substrates, the angle between the liquid crystal domain in the pixel region near the substrate on the element observation side and the substrate normal of the cholesteric spiral axis of the liquid crystal is the pixel region near the substrate on the opposite side. Is preferably larger than the angle formed by the cholesteric spiral axis of the liquid crystal and the substrate normal in the liquid crystal domain.

In any case, in the second liquid crystal light modulating element according to the present invention, the alignment control layers that are in contact with the liquid crystal are provided on the sides of the pair of substrates facing the liquid crystal layer, respectively. In the above, the angle between the cholesteric spiral axis of the liquid crystal and the substrate normal in each liquid crystal domain of the pixel region near both substrates may be controlled by the alignment control layer. Due to the control by the alignment control layer, the angle between the liquid crystal domains in the pixel regions near the two substrates and the cholesteric helical axis of the liquid crystal with the substrate normal is generated. The following cases (c) and (d) can be exemplified as examples of the magnitude of the angle. That is, (c) a case where at least one of the alignment control layers provided on both substrates is rubbed. In this case, it is preferable that the rubbed density of the rubbed orientation control layer is 10 or less. The angle may be varied by partially rubbing the orientation control layer, for example, by performing rubbing through a mask having a predetermined pattern of openings. In either case, depending on the alignment film material and the rubbing conditions, the orientation control layer does not form a monodomain, and a polydomain having a smaller inclination of the helical axis than the original state can be obtained as a whole. (D) A case where at least one of the alignment control layers provided on both substrates is irradiated with predetermined light. In this case, the magnitude of the angle formed between the liquid crystal domains in the pixel regions near the two substrates and the substrate normal of the cholesteric spiral axis of the liquid crystal may be controlled by the irradiation amount of the predetermined light on the alignment control layer. It may be controlled by the substrate temperature when irradiating the predetermined light to the alignment control layer, or may be controlled by the light irradiation angle to the substrate surface when irradiating the predetermined light to the alignment control layer. . The angle may be changed by partially irradiating the alignment control layer with light, for example, by irradiating light through a mask having a predetermined pattern of openings. In either case, depending on the alignment film material and light irradiation conditions, the orientation control layer does not become a monodomain, and a polydomain having a smaller inclination of the helical axis than the original state can be obtained as a whole. In any case, the predetermined light can be exemplified by ultraviolet light.

In the above cases (c) and (d), the inclination of the helical axis of the liquid crystal molecules in the region subjected to the rubbing treatment or light irradiation treatment of the alignment control layer is not more vertical than that in the other regions. It is considered that the average inclination of the helical axis of the liquid crystal molecules becomes smaller as a whole as compared with that before the processing by reducing the size.

In the second liquid crystal light modulation device according to the present invention, an alignment control layer which is in contact with the liquid crystal is provided on each of the pair of substrates on the side facing the liquid crystal layer. When the angle of the cholesteric spiral axis of the liquid crystal in each liquid crystal domain of the pixel region with respect to the substrate normal is controlled by the alignment control layer, the alignment control layers provided on the two substrates have different material parameters. You may. In this case, the angle between the cholesteric spiral axis of the liquid crystal and the substrate normal in each liquid crystal domain of the pixel region near the two substrates is controlled by each alignment control layer provided on the two substrates and having different material parameters. You. As a material used for each of the orientation control layers, a material parameter is different for each orientation control layer,
For example, different types of materials can be used for each orientation control layer. Examples of the material parameter include, but are not limited to, a pretilt angle. Further, as described later, the angle may be controlled by partially changing the material of the orientation control layer.

In each of the first and second liquid crystal light modulating elements according to the present invention, in the selective reflection state, the substrate normal to the cholesteric helical axis of the liquid crystal in each liquid crystal domain in the pixel region near the two substrates. It is desirable that the angle formed is 20 ° or less on average, and more preferably 20 ° or less for all liquid crystal domains. When this angle becomes larger than 20 °, the above-mentioned bistability deteriorates.

According to the study of the present inventors, a liquid crystal light modulation element that sandwiches a liquid crystal layer between a pair of substrates and modulates light using the focal conic state of liquid crystal molecules contained in the liquid crystal layer is disclosed. It has been found that by aligning the directions of the helical axes of the cholesteric liquid crystal molecules in the focal conic state, scattering between domains is significantly reduced.

That is, when the direction of the helical axis of the liquid crystal molecules in the focal conic state is regularly arranged in a plane substantially parallel to the substrate surface, the light transmittance of the liquid crystal layer in the focal conic state is significantly improved, and Can be improved.

Therefore, in the first and second liquid crystal light modulation elements according to the present invention, the direction of the helical axis of the liquid crystal molecules in the focal conic state is regularly arranged in a plane substantially parallel to the substrate surface. It may be. By doing so, the directions of the helical axes of the cholesteric liquid crystal molecules in the focal conic state are aligned, and light scattering in the device is reduced. Thereby, the light transmittance of the liquid crystal layer in the focal conic state is improved, and the contrast can be improved.

In this case, in order to regularly align the direction of the helical axis of the liquid crystal molecules in the focal conic state in a plane substantially parallel to the substrate surface, the liquid crystal element may be provided with a liquid crystal molecule alignment regulating means. Good.

As the alignment controlling means, a region partially provided with a different alignment controlling force on at least one surface of the substrate in contact with the liquid crystal can be employed. With this region, the direction of the helical axis of the liquid crystal can be regularly arranged. When regions having different alignment regulating forces are provided in this manner, in the process of transitioning the liquid crystal molecules to the focal conic state, the direction of the helical axis is determined by the difference in surface regulating force, so that the direction of the helical axis of the liquid crystal is regularly regulated. Can be arranged.

The regions having different alignment regulating forces can be formed by rubbing or irradiating light. It can also be formed by a method of partially rubbing, a method of partially irradiating light, a method of partially using different materials, or the like.

In the above-described method of performing rubbing entirely or partially and the method of performing light irradiation entirely or partially, in the first liquid crystal light modulation device of the present invention, the alignment control layer is provided. In this case, the method may be the same as that performed when the alignment of the liquid crystal molecules in the mixed state of the liquid crystal layer in the selective reflection state is controlled by the alignment control layer. Further, a method of performing rubbing entirely or partially, a method of performing light irradiation entirely or partially, and a method of using partially different materials are described in the second liquid crystal light modulation element of the present invention. In the case where a layer is provided, the angle between the cholesteric spiral axis of the liquid crystal and the substrate normal in each liquid crystal domain of the pixel region near the two substrates of the liquid crystal layer in the selective reflection state is controlled by the alignment control layer. A method similar to the method performed in the case may be used.

Therefore, in the first liquid crystal light modulation element, a mono-domain and poly-domain mixed state can be obtained, and at the same time, a focal conic state with less scattering can be realized. Also, in the second liquid crystal light modulation element, when the inclination of the helical axis is made different from that of the other substrate by partial rubbing treatment, partial light alignment treatment, or partially changing the material, A focal conic state with less scattering can be realized.

More specifically, the first liquid crystal light modulating element is
Since it has regions with different alignment control forces that generate monodomains and polydomains, this region allows the orientation of the helical axis due to the difference in surface control forces during the transition of liquid crystal molecules to the focal conic state. Thus, the direction of the helical axis of the liquid crystal can be regularly arranged, and it is considered that scattering of the focal conic state is reduced. Also, in the second liquid crystal light modulation element, even if a complete monodomain region cannot be obtained due to partial rubbing treatment, partial light alignment treatment, partially dissimilar materials, etc., the inclination of the helical axis for each minute region is reduced. Since the liquid crystal molecules are different from other regions, the direction of the helical axis is determined by the difference in the surface regulation force during the transition of the liquid crystal molecules to the focal conic state, and the direction of the helical axis of the liquid crystal is regularly arranged. It is considered that scattering of the focal conic state can be reduced.

When the width of the region where the alignment regulating force is different is W and the helical pitch of the liquid crystal is p, the width W and the helical pitch p are preferably set in the following relationship.

P <W <20p When the arrangement pitch of the regions having different alignment regulating forces is L and the helical pitch of the liquid crystal is p, the arrangement pitch L and the helical pitch p are preferably set in the following relationship.

5p <L <100p By setting the width W and the arrangement pitch L of the regions having different alignment regulating forces within the above ranges, a favorable regulating force for the liquid crystal molecules is maintained, and the device manufacturing process becomes complicated. Can be prevented.

The arrangement pitch of the regions having different alignment regulating forces may be non-uniform within the above range. By making the arrangement pitch of the regions having different alignment regulating forces non-uniform, it is possible to prevent a decrease in visibility due to a light diffraction phenomenon.

In any case, a plurality of pixels may be provided in the pixel area. In this case, the arrangement direction of the regions having different alignment regulating forces may be different from the pixel arrangement direction of the plurality of pixels, and the arrangement directions of the regions having different alignment regulating forces may have a plurality of regions different from each other. You may. By doing so, the visibility does not change depending on the light incident direction, and uniform light transmission characteristics can be obtained.

In the first and second liquid crystal light modulation elements according to the present invention, when the direction of the helical axis of the liquid crystal molecules in the focal conic state is regularly arranged in a plane substantially parallel to the substrate surface, As a liquid crystal material exhibiting a cholesteric phase at room temperature, a material having a positive dielectric anisotropy may be used.

The present invention also provides the following laminated liquid crystal light modulation device. That is, (3) a laminated liquid crystal light modulating element, which is a laminated liquid crystal light modulating element in which a plurality of liquid crystal layers each sandwiched between a pair of substrates are laminated, and at least one liquid crystal of the plurality of liquid crystal layers A laminated liquid crystal light modulation device, wherein the layer constitutes the liquid crystal light modulation device together with a pair of substrates sandwiching the liquid crystal layer.

In this stacked liquid crystal light modulation device, multicolor display (that is, two-color display) is performed by using different liquid crystal layers having mutually different peak wavelengths of selective reflection as a plurality of liquid crystal layers. Color display over color)
It can be performed. Note that full-color display can be performed by using at least three liquid crystal layers of a liquid crystal layer for performing blue display, a liquid crystal layer for performing green display, and a liquid crystal layer for performing red display. Further, at least two optical rotation directions different from each other.
One liquid crystal layer may be included, and in this case, the light use efficiency can be increased. The peak wavelength of selective reflection of each liquid crystal layer having a different optical rotation direction may be substantially the same, and in this case, the light reflectance from the liquid crystal layer can be increased.

In any case, as such a laminated liquid crystal light modulation element, a laminated liquid crystal in which a plurality of liquid crystal light modulation elements including at least one liquid crystal light modulation element according to the present invention (or all of them) may be laminated. A light modulation element can be exemplified. In this case, adjacent liquid crystal light modulation elements may have a common substrate between them.

In any of the laminated liquid crystal light modulation elements according to the present invention, the following cases can be exemplified as preferred embodiments. (E) In each of the adjacent liquid crystal light modulation elements, in the liquid crystal light modulation element in the selective reflection state on the element observation side, the substrate normal of the cholesteric spiral axis of the liquid crystal in the liquid crystal domain of the pixel region near the substrate on the element observation side. The angle formed is greater than the angle formed by the cholesteric spiral axis of the liquid crystal in the liquid crystal domain of the pixel region near the substrate on the element observation side in the selective reflection state on the side opposite to the element observation side with the substrate normal. (F) In each adjacent liquid crystal light modulation element, the substrate method of the cholesteric spiral axis of the liquid crystal in the liquid crystal domain in the pixel region near the substrate on the side opposite to the element observation side in the liquid crystal light modulation element in the selective reflection state on the element observation side. The angle between the line and the substrate normal to the cholesteric spiral axis of the liquid crystal in the liquid crystal domain of the pixel region near the substrate opposite to the element observation side in the liquid crystal light modulation element in the selective reflection state opposite to the element observation side. If greater than the angle to be made. (G) When the above (e) and (f) are combined.

In any case, in each liquid crystal light modulation element of the laminated liquid crystal light modulation element, the alignment control layer is provided on the substrate facing the liquid crystal domain in which the poly domain and the mono domain are mixed. When the control layer is rubbed, in each adjacent liquid crystal light modulation element, the rubbing density of the rubbed alignment control layer in the liquid crystal light modulation element on the element observation side is the same as the element observation side corresponding to the alignment control layer. Is more preferably smaller than the rubbing density of the rubbed alignment control layer in the liquid crystal light modulation element on the opposite side.

The stacked liquid crystal light modulation device according to the present invention may include a liquid crystal layer in which the direction of the helical axis of the liquid crystal molecules in the focal conic state is regularly arranged in a plane substantially parallel to the substrate surface. Good. In this case, at least the liquid crystal layer on the outermost surface side (device observation side) may be a liquid crystal layer in which the direction of the helical axis of the liquid crystal molecules in the focal conic state is regularly arranged in a plane substantially parallel to the substrate surface. . In any case, it is possible to effectively suppress an increase in light transmittance in the focal conic state due to an increase in scattering components caused by stacking a plurality of liquid crystal layers.

The present invention also provides the following first and second manufacturing methods of the liquid crystal light modulation device capable of manufacturing the above-described liquid crystal light modulation device according to the present invention. Regarding both the first and second manufacturing methods and the liquid crystal light modulation element manufactured by the method, the same can be said for the first and second liquid crystal light modulation elements. (4) First Method for Manufacturing Liquid Crystal Light Modulating Element A cholesteric phase is shown at room temperature between a pair of substrates (usually at least one of them is a pair of transparent substrates) and has a selective reflection wavelength peak in a visible wavelength region. A method for manufacturing a liquid crystal light modulation element sandwiching a liquid crystal layer containing a liquid crystal material, wherein a liquid crystal domain in a pixel region near at least one of substrates near the two substrates in the selective reflection state has a polycrystalline domain. A substrate processing step of processing at least one substrate of the pair of substrates so that a domain and a monodomain are mixed, between the pair of substrates where at least one substrate is processed in the substrate processing step And a step of sandwiching the liquid crystal layer. (5) Second Method for Manufacturing Liquid Crystal Light Modulating Element A cholesteric phase is shown at room temperature between a pair of substrates (usually at least one pair of transparent substrates) and has a peak of a selective reflection wavelength in a visible wavelength region. A method of manufacturing a liquid crystal light modulation element sandwiching a liquid crystal layer containing a liquid crystal material, wherein each liquid crystal domain in a pixel region near the substrate facing the two substrates of the liquid crystal layer in the selective reflection state, all take a poly domain structure, A substrate processing step of processing the pair of substrates, so that the angle formed by the cholesteric spiral axis of the liquid crystal and the substrate normal is different between the liquid crystal domains in the pixel regions near the two substrates, and the substrate processing step A step of sandwiching the liquid crystal layer between a pair of substrates.

In the first method of manufacturing a liquid crystal light modulation device according to the present invention, in the substrate processing step, the liquid crystal layer in the selective reflection state may be a pixel near at least one of the substrates near the two substrates. At least one of the pair of substrates is processed so that the liquid crystal domains in the region are in a mixed state of the poly domain and the mono domain, and at least one of the pair of substrates is processed by at least one of the substrates in the substrate processing step. The liquid crystal layer is sandwiched between substrates. Thus, the first liquid crystal light modulation device according to the present invention can be manufactured.

In the second method for manufacturing a liquid crystal light modulation device according to the present invention, in the substrate processing step, each of the liquid crystal domains in a pixel region of the liquid crystal layer in the selective reflection state near the substrates facing both substrates is all Taking a polydomain structure, processing the pair of substrates so that the angle formed between the liquid crystal domains in the pixel regions near the two substrates and the substrate normal of the cholesteric spiral axis of the liquid crystal is different, and the substrate is processed in this substrate processing step. The liquid crystal layer is sandwiched between the pair of substrates. Thus, the second liquid crystal light modulation device according to the present invention can be manufactured.

According to the first and second manufacturing methods of the liquid crystal light modulation device according to the present invention, in the first manufacturing method of the liquid crystal light modulation device, the substrate of the liquid crystal layer in the selective reflection state facing the two substrates is provided. The first liquid crystal light modulation element according to the present invention, in which the liquid crystal domains in the pixel region near at least one of the substrates are a mixture of poly domains and mono domains, can be manufactured. In the manufacturing method of (1), each liquid crystal domain in the pixel region near the substrate facing the two substrates of the liquid crystal layer in the selective reflection state has a polydomain structure, and the liquid crystal domain between the liquid crystal domains in the pixel region near the two substrates. The second aspect according to the present invention, wherein the angle formed by the cholesteric spiral axis and the substrate normal is different.
Liquid crystal light modulation element can be manufactured, and it is possible to display a good image with high brightness, high contrast, and high color purity.
For example, it is possible to obtain a liquid crystal light modulation element capable of maintaining a display state (a good image state having high brightness, contrast, and color purity) for a long time when no voltage is applied. In other words, it is possible to obtain a liquid crystal light modulation element that can achieve both high reflection intensity, high contrast, and high color purity and bistability.

In the first method of manufacturing a liquid crystal light modulation device according to the present invention, in the substrate processing step, all the liquid crystal domains in the pixel regions near both substrates in the selective reflection state are in the mixed state. The pair of substrates may be processed, or one of the liquid crystal domains in the pixel region near the two substrates in the selective reflection state may be in the mixed state, and the other liquid crystal domain may be composed of only the poly domains. As described above, the pair of substrates may be processed.

When the liquid crystal domains in the pixel regions near the two substrates are processed so as to be in the mixed state, the ratio of the mixed poly domains and mono domains between the liquid crystal domains in the pixel regions near the two substrates is determined. Are preferably treated differently. More preferably,
The processing may be performed such that the liquid crystal domain in the pixel region near the substrate on the element observation side becomes the liquid crystal domain having a higher polydomain ratio.

When processing is performed such that one of the liquid crystal domains in the pixel regions near the two substrates is in the mixed state and the other liquid crystal domain is composed only of the poly domains, the pixel near the two substrates is required. In the liquid crystal domains in the region, the liquid crystal domains in the pixel region near the substrate on the side opposite to the element observation side are in the mixed state, and the liquid crystal domains in the pixel region near the substrate on the element observation side are composed of only the poly domains. May be processed.

In any one of the first manufacturing methods of the liquid crystal light modulation element of the present invention, the substrate processing step may include the step of at least the side of the pair of substrates facing the liquid crystal domain in the mixed state. And a rubbing step of rubbing the alignment control layer provided on the substrate facing the liquid crystal domains in the mixed state. In this case, in the rubbing treatment step, the rubbing density of the rubbed orientation control layer is set to 10%.
It is desirable to make the following. The element that realizes the mixed state may be obtained by partially rubbing the orientation control layer, for example, by performing rubbing through a mask having openings of a predetermined pattern.

Further, the substrate processing step includes a step of providing an alignment control layer on at least a side of the pair of substrates facing the liquid crystal domains in the mixed state, the substrate facing the liquid crystal domains in the mixed state. A light irradiation step of irradiating predetermined light for orientation control to the orientation control layer provided on the facing substrate. In this case, in the light irradiation step, the irradiation amount of the predetermined light to the alignment control layer may be changed, or the substrate temperature at the time of irradiation of the predetermined light to the alignment control layer may be changed. Alternatively, the light irradiation angle with respect to the substrate surface when the predetermined light is irradiated on the alignment control layer may be changed. The element that realizes the mixed state may be obtained by partially irradiating the alignment control layer with light, for example, by irradiating light through a mask having a predetermined pattern of openings. In any case, the predetermined light can be exemplified by ultraviolet light.

In such a substrate processing step, depending on processing conditions (for example, depending on the degree of rubbing when the rubbing step is included, the amount of light irradiation, the substrate temperature during light irradiation, Depending on the angle of light irradiation with respect to the substrate surface during irradiation), it is possible to control the viewing angle of the obtained liquid crystal light modulation element.

In the second method of manufacturing a liquid crystal light modulation element according to the present invention, in the substrate processing step, of the liquid crystal domains in the pixel regions near the two substrates in the selective reflection state, the pixels near the substrate on the element observation side are selected. The angle formed by the cholesteric helical axis of the liquid crystal in the liquid crystal domain of the region and the substrate normal to the substrate normal of the cholesteric helical axis of the liquid crystal in the liquid crystal domain of the pixel region near the opposing substrate is larger than the angle formed by the substrate. A pair of substrates may be processed.

In any of the second liquid crystal light modulation device manufacturing methods according to the present invention, the substrate processing step includes a step of providing an alignment control layer on each of the pair of substrates on a side facing the liquid crystal layer, A rubbing step of rubbing at least one of the orientation control layers provided on both substrates. In this case, it is desirable that the rubbing density of the alignment control layer to be rubbed in the rubbing step is 10 or less. The element that realizes the mixed state may be obtained by partially rubbing the orientation control layer, for example, by performing rubbing through a mask having openings of a predetermined pattern.

In the substrate processing step, an alignment control layer is provided on each of the pair of substrates on the side facing the liquid crystal layer, and at least one of the alignment control layers provided on the two substrates is provided. Irradiating the control layer with predetermined light. In this case, in the light irradiation step, the irradiation amount of the predetermined light to the alignment control layer may be changed, or the substrate temperature at the time of irradiation of the predetermined light to the alignment control layer may be changed. Alternatively, the light irradiation angle with respect to the substrate surface when the predetermined light is irradiated on the alignment control layer may be changed. The element that realizes the mixed state may be obtained by partially irradiating the alignment control layer with light, for example, by irradiating light through a mask having a predetermined pattern of openings. In any case, the predetermined light can be exemplified by ultraviolet light.

Further, the substrate processing step may include a step of providing an alignment control layer on the side of the pair of substrates facing the liquid crystal layer so that material parameters are different from each other. In this case, as the material used for the orientation control layers, for example, different types of materials can be used for the respective orientation control layers such that the material parameters differ for each orientation control layer. This material parameter includes, but is not limited to, for example, a pretilt angle. The angle may be controlled by partially changing the material of the orientation control layer.

In such a substrate processing step, depending on processing conditions (for example, depending on the degree of rubbing when the rubbing step is included, the amount of light irradiation, the substrate temperature during light irradiation, The liquid crystal light modulation element obtained by the degree of the light irradiation angle with respect to the substrate surface at the time of irradiation, or by selecting the material used for the alignment control layer in the case of including the step of providing each alignment control layer so that the material parameters are different from each other Can be controlled.

In any case, in the first and second manufacturing methods of the liquid crystal light modulation element according to the present invention, in the substrate processing step, in each of the liquid crystal domains of the pixel regions near the two substrates in the selective reflection state. It is desirable that the angle between the cholesteric spiral axis of the liquid crystal and the substrate normal is 20 ° or less on average, and more preferably 20 ° or less for all liquid crystal domains.

The method of manufacturing the first and second liquid crystal light modulating elements according to the present invention is also directed to a method in which the direction of the helical axis of the liquid crystal molecules in the focal conic state is regularly arranged on at least one of the substrates in contact with the liquid crystal. In order to align the liquid crystal layer, a step of partially providing a region having a different alignment regulating force, and a step of sandwiching a liquid crystal layer between a pair of substrates provided with a region having a partially different alignment regulating force on at least one side. May be.

In this manufacturing method, when forming the regions having different alignment regulating forces, the shapes, positions, arrangement pitches, arrangement directions, etc. can be arbitrarily formed. Therefore, it is easy to control the regulation of the alignment of the liquid crystal. Further, a step for providing another member for regulating the alignment of the liquid crystal is not required.

In the step of partially providing a region having a different alignment regulating force, the region may be formed by rubbing the entire surface or part of the region, or light irradiation may be performed entirely or partially. May form the region. In any case, the step of partially providing a region having a different alignment regulating force includes a step of arranging a mask layer partially provided with an opening on a substrate, and a step of removing the mask layer. May be.

In the step of partially providing regions having different alignment controlling forces, regions having different alignment controlling forces may be formed by partially forming alignment films of different material types.

The above-described method of performing full or partial rubbing and the method of performing full or partial light irradiation are described in the rubbing process in the first and second methods for manufacturing a liquid crystal light modulation element of the present invention. You can take advantage of the techniques performed.
In addition, the method using partially different materials is the second method of the present invention.
In the method of manufacturing a liquid crystal light modulation device described above, a method performed in the step of providing alignment control layers such that material parameters are different from each other on the side facing the liquid crystal layer of the pair of substrates can be used.

[0082]

Embodiments of the present invention will be described below with reference to the drawings.

The liquid crystal light modulation element (liquid crystal display element here) according to the present invention can be formed, for example, in the following structure.

FIG. 1 is a schematic sectional view of an example of the liquid crystal light modulation device according to the present invention.

In the liquid crystal light modulation device shown in FIG. 1, a liquid crystal layer 10 containing a liquid crystal material 6 showing a cholesteric phase at room temperature between a pair of substrates 1 and 2 and having a selective reflection wavelength peak in a visible wavelength region. It is pinched. A resin structure 4 and a spacer 5 are disposed between the two substrates 1 and 2 as a space holding material for maintaining a space between the two substrates. The resin structure 4 also contributes to the connection between the two substrates.

The element observation side P (the side on which light is incident)
On the outer surface (back surface) of the substrate on the opposite side, if necessary,
A visible light absorbing layer is provided. In the example of FIG. 1, a visible light absorbing layer 3 is provided on the outer surface (back surface) of the substrate 2. For example,
For example, a black substrate may be used as the substrate 2 so that the substrate itself has a light absorbing function.

S is a sealing material for sealing the liquid crystal material 6 between the substrates 1 and 2.

In the liquid crystal light modulation device shown in FIG. 1, display is performed by switching the liquid crystal 6 between a planar state (selective reflection state) and a focal conic state by applying a predetermined voltage.

The substrates 1 and 2 are substrates at least one of which has translucency. As a light-transmitting substrate,
A glass substrate can be exemplified. In addition to this glass substrate, for example, polycarbonate, polyether sulfone (PES),
A flexible substrate such as polyethylene terephthalate can be used. When the liquid crystal light modulation device according to the present invention is used as a reflection type liquid crystal light modulation device, one of the substrates does not need to be transparent, in other words, both need not be transparent. Here, each of the substrates 1 and 2 has translucency.

In the liquid crystal light modulation device of the present invention, not only the liquid crystal light modulation device shown in FIG. 1 but also electrodes can be formed on a pair of substrates as needed.

As the electrodes, for example, ITO (Indium T
in Oxide: a transparent conductive film typified by indium tin oxide, a metal electrode such as aluminum or silicon, amorphous silicon, or BSO (Bismuth Silicon Oxide)
And the like can be used. Such an electrode is provided in a desired pattern on the substrate for holding the liquid crystal light modulation element layer, and is used as an electrode for controlling the liquid crystal display element. Examples of the electrode pattern shape include a plurality of strip patterns formed in parallel with each other. The pair of substrates on which the strip-shaped pattern electrodes are formed face each other such that the electrodes cross each other. That is, in the liquid crystal light modulation device of the present invention, a simple matrix type electrode structure can be used. Further, an active matrix type electrode structure including a plurality of pixel electrodes and a thin film transistor connected thereto can be used.

In addition to disposing the electrode material on the substrate for holding the liquid crystal light modulation element layer, the electrode itself can be used as the substrate material.

FIG. 2 is a schematic plan view of a pixel pattern of the liquid crystal light modulation device shown in FIG.

In the liquid crystal light modulation device shown in FIG. 1, as described above, the substrates 1 and 2 are transparent substrates having translucency.
On each of the surfaces of the transparent substrates 1 and 2, there are provided a plurality of transparent electrodes 11 and 12 which are formed in a plurality of parallel bands. These transparent electrodes 11 and 12 face each other so as to cross each other, and a region where the electrodes 11 and 12 overlap is a pixel region X (see FIG. 2).

The liquid crystal light modulation device of the present invention, including the liquid crystal light modulation device shown in FIG. 1, may have an insulating film having a function of improving the reliability of the liquid crystal light modulation device as a gas barrier layer and an insulating layer. . As this insulating film, a film made of any organic or inorganic material can be exemplified. Here, the insulating films 7 are provided on the electrodes 11 and 12, respectively.

Not only the liquid crystal material 6 but also a liquid crystal material that can be used in the liquid crystal light modulation element according to the present invention exhibits a cholesteric phase when sandwiched between a pair of substrates (for example, a pair of substrates with electrodes). Can be exemplified. For example,
Cholesteric liquid crystals having a cholesterol ring can be mentioned. In addition, a nematic liquid crystal having an optically active group in the nematic liquid crystal, a cholesteric liquid crystal, or a chiral nematic liquid crystal obtained by adding a chiral agent to the nematic liquid crystal can be used. These materials (nematic liquid crystal, cholesteric liquid crystal, chiral agent) may be a single material, or not only a single nematic liquid crystal, cholesteric liquid crystal, and chiral agent but also a mixed material of two or more types.

As the liquid crystal having a selective reflection wavelength peak in the visible wavelength range, a cholesteric liquid crystal having a helical pitch effective for reflecting light in the visible wavelength range by itself can be exemplified. In addition, a material in which an appropriate amount of a material having an optically active group is mixed with a nematic liquid crystal material to adjust the helical pitch can be used. Regarding which wavelength range to set the visible wavelength range, there is generally some variation in the concept of the visible wavelength range, and there may be some variation in the setting. The visible wavelength range is set to a range from 400 nm to 700 nm in the present embodiment and an experimental example described later. In addition, the cholesteric selective reflection type liquid crystal light modulation element includes a scattering component in a wavelength region shorter than the selective reflection wavelength region. Alternatively, a dye that absorbs light in a short wavelength range may be added.

FIG. 3 shows an example of each liquid crystal domain in the pixel region X near the substrate facing both substrates 1 and 2 of the liquid crystal layer 10 in the selective reflection state of the liquid crystal light modulation device shown in FIG.
In FIG. 3, the insulating film 7 and the like are not shown.

The liquid crystal light modulation device shown in FIG. 1 is arranged such that each liquid crystal domain in the pixel region X near the substrate facing both substrates 1 and 2 of the liquid crystal layer 10 in the selective reflection state is in one of the following states. Form. (1) In the selective reflection state, the liquid crystal domain of the liquid crystal layer 10 in the pixel region X near at least one of the substrates 1a and 2a facing the two substrates 1 and 2 is a mixed state of the poly domain and the mono domain. (Fig. 3
(A)). (2) Both substrates 1 of the liquid crystal layer 10 in the selective reflection state
Each of the liquid crystal domains in the pixel regions X near the substrates 1a and 2a facing the substrate 2 has a polydomain structure, and the cholesteric spiral axes 61 and 62 of the liquid crystal 6 are interposed between the liquid crystal domains in the pixel regions X near the two substrates 1a and 2a. Substrate normal H
The angles θ1 and θ2 are different (see FIG. 3B).

Here, the “polydomain” is an area in which the spiral axis of the liquid crystal is slightly inclined from the substrate normal line in the selective reflection wavelength state of the liquid crystal, and the projection direction of the spiral axis onto the substrate is randomly different. The “monodomain” is a region where the helical axis of the liquid crystal is equalized perpendicular to or substantially perpendicular to the substrate surface.

The case (1) will be described with reference to the example of FIG. 3A. One of the liquid crystal domains in the pixel regions X in the vicinity 1a, 2a of both substrates is in the mixed state (FIG. 3A). The symbol M indicates a monodomain.)
And the other liquid crystal domain is composed of only the poly domain. More specifically, the liquid crystal domains in the pixel region X near the substrate 2a on the opposite side to the element observation side P among the liquid crystal domains in the pixel regions X near the two substrates 1a and 2a are in the mixed state. The liquid crystal domain in the pixel region X near the substrate 1a is composed of only the poly domain.

An orientation control layer 82 is provided on at least one of the substrates 1 and 2 facing the liquid crystal domain in the mixed state on the side facing the liquid crystal domain. Of the liquid crystal molecules 60 is controlled by the alignment control layer 82. As the orientation control, the following cases (a) and (b) can be exemplified. (A) The case where the alignment control is performed by rubbing the alignment control layer 82 provided on the substrate 2 facing the mixed liquid crystal domain. In this case, it is desirable that the rubbed density of the rubbed orientation control layer 82 is 10 or less. The mixed state may be realized by partially rubbing the orientation control layer, for example, by performing rubbing through a mask having a predetermined pattern of openings. (B) The case where the alignment control is performed when the alignment control layer 82 provided on the substrate 2 facing the mixed liquid crystal domain is irradiated with predetermined light. in this case,
The alignment control may be determined by the irradiation amount of the predetermined light to the alignment control layer 82, may be determined by the substrate temperature at the time of irradiation of the predetermined light to the alignment control layer 82,
Further, it may be determined by a light irradiation angle with respect to the substrate surface when the predetermined light is irradiated on the alignment control layer 82. By irradiating light through a mask having a predetermined pattern of openings,
The mixed state may be realized by partially irradiating the orientation control layer with light. In any case, the predetermined light can be exemplified by ultraviolet light.

Here, the alignment control is performed by the alignment control layer 82 provided on the substrate 2 facing the mixed liquid crystal domain.
Is performed by being rubbed. The rubbing density of the rubbed orientation control layer 82 is 10 or less here.

Here, an alignment control layer 81 is also provided on the side of the substrate 1 facing the liquid crystal domain, which faces the liquid crystal domain composed of only the poly domains. The orientation control layer 81 is made of the same material as the orientation control layer 82, but is not rubbed.

The case (2) will be described with reference to the example shown in FIG. 3B. In the liquid crystal domains in the pixel regions X of the two substrates 1a and 2a, the substrate 1a near the element observation side P among the liquid crystal domains.
The angle θ1 between the cholesteric spiral axis 61 of the liquid crystal 6 and the substrate normal H of the liquid crystal 6 in the liquid crystal domain of the pixel region X is the substrate normal of the cholesteric spiral axis 62 of the liquid crystal 6 in the liquid crystal domain of the pixel region X near the opposite substrate 2a. H is larger than the angle θ2.

On the sides of the pair of substrates 1 and 2 facing the liquid crystal layer 10, alignment control layers 81 and 82 are provided so as to be in contact with the liquid crystal 6, respectively. The angles θ1 and θ2 between the cholesteric spiral axes 61 and 62 of the liquid crystal 6 and the substrate normal H in the domain are controlled by the alignment control layers 81 and 82. Due to the control by the alignment control layers 81 and 82, angles θ1 and θ2 between the cholesteric spiral axes 61 and 62 of the liquid crystal 6 and the substrate normal line H between the liquid crystal domains in the pixel regions X near the two substrates 1a and 2a are generated. I have. The following cases (c) and (d) can be exemplified as examples where the magnitude of the angle occurs. (C) the orientation control layer 81 provided on both substrates 1 and 2;
The case where at least one of the alignment control layers 82 is rubbed. In this case, it is preferable that the rubbed density of the rubbed orientation control layer is 10 or less. The angle may be varied by partially rubbing the orientation control layer, for example, by performing rubbing through a mask having a predetermined pattern of openings. In either case, depending on the alignment film material and the rubbing conditions, the orientation control layer does not form a monodomain, and a polydomain having a smaller inclination of the helical axis than the original state can be obtained as a whole. (D) an orientation control layer 81 provided on both substrates 1 and 2;
82, when at least one of the orientation control layers is irradiated with predetermined light. In this case, the magnitude of the angles θ1 and θ2 may be controlled by the irradiation amount of the predetermined light on the alignment control layer, or may be controlled by the substrate temperature when the predetermined light is irradiated on the alignment control layer. Alternatively, it may be controlled by a light irradiation angle with respect to the substrate surface when the predetermined light is irradiated on the alignment control layer. By irradiating light through a mask having a predetermined pattern of openings,
The angle may be varied by partially irradiating the orientation control layer with light. In any case, depending on the alignment film material and light irradiation conditions, the alignment control layer does not become a monodomain, and a polydomain having a smaller inclination of the helical axis than the original state can be obtained as a whole. In any case, the predetermined light can be exemplified by ultraviolet light.

Further, the material parameters of the alignment control layers 81 and 82 provided on the substrates 1 and 2 may be different from each other. In this case, the angles θ1 and θ2 between the cholesteric spiral axes 61 and 62 of the liquid crystal 6 and the substrate normal H in the liquid crystal domains of the pixel regions X in the vicinity of both substrates 1a and 2a are:
The material parameters provided on both substrates 1 and 2 are controlled by different orientation control layers 81 and 82, respectively. As a material used for each of the orientation control layers 81 and 82, for example, a different type of material can be used for each of the orientation control layers 81 and 82 so that the material parameters differ for each of the orientation control layers 81 and 82. Examples of the material parameter include, but are not limited to, a pretilt angle.

The magnitudes of the angles θ1 and θ2 are caused by the rubbing of the alignment control layers 81 and 82 provided on the substrates 1 and 2. The rubbing density of each of the rubbed orientation control layers 81 and 82 is 10 or less here.

Further, in the liquid crystal light modulation device shown in FIG. 1, in the selective reflection state, the substrate normal H of the cholesteric spiral axes 61 and 62 of the liquid crystal 6 in each liquid crystal domain of the pixel region X near both substrates 1a and 2a. Angles θ1, θ2
Is 20 ° or less.

In the liquid crystal light modulation device of the present invention, including the liquid crystal light modulation device shown in FIG. 1, the direction of the helical axis of the liquid crystal molecules in the focal conic state is reduced in order to reduce the light scattering effect in the focal conic state. They may be arranged regularly in a plane substantially parallel to the substrate surface.

In this case, in order to regularly align the direction of the helical axis of the liquid crystal molecules in the focal conic state in a plane substantially parallel to the substrate surface, it is possible to provide a liquid crystal element alignment control means in the liquid crystal element. Good.

Examples of the arrangement regulating means for regularly arranging the direction of the helical axis in a plane parallel to the substrate include a means for controlling the electric field and a means for varying the alignment regulating force. (A) Means by controlling electric field (projection-like structure or groove that causes anisotropy in the direction of the electric field) In the liquid crystal light modulation device shown in FIG. 1 in FIG. 1 shows a state in which a striated structure 13 is formed. FIG. 5 shows a state in which the equipotential lines 26 cause distortion in the vicinity of the projecting structure 13 in the liquid crystal light modulation device in which the projecting structure 13 having the rib structure is formed, and FIG. Shows a state in which is partially inclined in a specific direction. In FIG. 4, the resin structure 4 is not shown. The same applies to FIGS. 9 and 11 described below.

As shown in FIG. 4, when the protruding structure 13 having the rib structure is provided on one of the substrates 2, when the protruding structure 13 is provided, a voltage is applied between the electrodes 11 and 12. In addition, as shown in FIG. 5, the equipotential lines 26 cause distortion near the protruding structure 13. Therefore, as shown in FIG. 6, the electric field direction E is partially inclined in a specific direction. And
In this state, the application of voltage is stopped and the liquid crystal is
When in the conic state, it is considered that the direction of the helical axis of the liquid crystal is regulated by the influence of the tilted electric field existing up to then, and as a result, as shown in FIG. 7 and FIG. , The spiral axes 61 of the liquid crystal are regularly aligned. Therefore, it is possible to realize a focal conic state in which the helical axis 61 of the liquid crystal molecules is directed in a certain direction and light scattering is small. The state shown in FIG. 8 is a state when the liquid crystal light modulation element is viewed from above.

Incidentally, as the protruding structure, the aforementioned structure 1
The shape is not limited to 3, and various shapes can be used.

FIG. 9 shows a state in which a groove (slit) 15 which is another example of the arrangement regulating means is formed in the electrode 12 in the liquid crystal light modulation device shown in FIG. FIG. 10 shows a state in which the equipotential line 26 is distorted in the vicinity of the slit 15 in the liquid crystal light modulation element in which the slit 15 is formed in the electrode 12.

Even when the slit 15 is formed in the transparent electrode 12 as shown in FIG. 9, the equipotential line 26 is also distorted near the slit 15 as shown in FIG.
For the same reason, it is possible to realize a focal conic state in which the helical axis of the liquid crystal is oriented in a certain direction and the scattering is small.

The grooves are not limited to those formed on the electrodes. For example, it may be formed on an insulating film or the like. (B) Means by Differentiating Arrangement Control Force Another means for regularly arranging the direction of the helical axis in a plane parallel to the substrate includes regions having different alignment control forces. The regions having different alignment regulating forces are regions having different anchoring forces and alignment directions for liquid crystal molecules. The regions having different alignment regulating forces can be obtained by rubbing an alignment film (alignment control layer) made of polyimide or the like uniformly coated on the electrode surface or by performing a photo alignment process using ultraviolet rays or the like. In particular, rubbing having a low density (for example, having a Rabink density of 10 or less) is applied to the entire alignment control layer, the alignment control layer is partially rubbed by using a mask having a predetermined pattern of openings, or a predetermined pattern is rubbed. It is preferable to form regions having different alignment regulating forces by partially irradiating light, for example, by irradiating light through a mask having an opening. In addition, regions having different alignment regulating forces can be obtained by partially forming alignment films of different material types.

In such a region having a different alignment regulating force, the inclination of the helical axis due to the difference in the surface regulating force is not caused in the process of transition of the liquid crystal molecules to the focal conic state, but the inclination of the electric field direction is caused by rubbing treatment or the like. It is considered that the same effect as the above-described means for inclining the direction of the electric field can be obtained because the direction is set.

In any case, when the orientation of the helical axis is regularly arranged in a plane parallel to the substrate by performing such an alignment treatment, it is not necessary to add a new member to the liquid crystal element, so that the reliability is improved. There is an advantage that the property is enhanced. In particular, the photo-alignment treatment is an excellent means that has little possibility of generating dust and the like.

The method of performing rubbing entirely or partially and the method of irradiating light entirely or partially are described in the first liquid crystal light modulation device according to the present invention, in which an alignment control layer is provided. A method similar to the alignment control method performed when the alignment of the liquid crystal molecules in the mixed state of the liquid crystal layer in the selective reflection state is controlled by the alignment control layer (here, in the case of FIG. 3A). Further, a technique of partially rubbing, a technique of partially irradiating light, and a technique of using partially different materials are described in the second aspect of the present invention.
When the alignment control layer is provided in the liquid crystal light modulation device of the above, the angle between the cholesteric spiral axis of the liquid crystal and the substrate normal in each liquid crystal domain of the pixel region near both substrates of the liquid crystal layer in the selective reflection state is defined as the angle. It may be the same as the alignment control method performed in the case where the alignment is controlled by the alignment control layer (here, the case of FIG. 3B). As described above, by using a method similar to the above-described alignment control method, it is possible to realize the mixed state and the difference in angle between the upper and lower substrates, and also to realize the focal conic state with less scattering.

FIG. 11 shows an example in which, in the liquid crystal light modulation device shown in FIG. 1, the region 16 partially processed by such a method is provided on an alignment control layer (alignment film) 82.

The orientation control layer provided with the partially treated region is provided with liquid crystal molecules so as to obtain the mixed state of the liquid crystal layer in the selective reflection state as shown in FIG. 3A. May be capable of controlling the orientation. Further, as in the case of FIG. 3B, it is possible to control the angle between the cholesteric spiral axis of the liquid crystal and the substrate normal in each liquid crystal domain of the pixel region near both substrates of the liquid crystal layer in the selective reflection state. It may be something. In any case, in the focal conic state, the direction of the helical axis can be regularly arranged in a plane parallel to the substrate.

As a method for controlling the angle between the cholesteric spiral axis of the liquid crystal and the substrate normal in each liquid crystal domain of the pixel region near the two substrates in the selective reflection state,
It is also effective to appropriately select the material type and processing method of the outermost surface of the substrate (for example, a film on the substrate surface) facing the cholesteric liquid crystal held in accordance with the cholesteric liquid crystal material type.

When the outermost surface of the substrate is a film, as the material of the uppermost surface of the substrate, polyimide can be used in addition to the above-mentioned electrode material and the material used for the insulating film. Among them, polyimide is most suitable from the viewpoint that the interaction with cholesteric liquid crystal can be easily changed by the alignment treatment described later. The thickness of the film may be such that a voltage can be applied to the cholesteric liquid crystal layer and the light transmittance is not significantly reduced.

As a method of performing the orientation treatment, a rubbing method in which the surface of the portion to be subjected to the orientation treatment is rubbed in one direction with a cloth or the like, and when the outermost surface of the substrate is a film (for example, a polyimide film), Irradiation of non-polarized light or linearly polarized light (eg, ultraviolet light) to the film to cause a reaction such as isomerization, dimerization, or decomposition to cause anisotropy is preferable.

In the case where the rubbing method is employed, a rubbing roller having a rubbing cloth having a predetermined bristle length is provided.
A rubbing device that rubs the outermost surface of the substrate by moving the substrate at a predetermined speed in a predetermined direction and bringing the rubbing roller rotating at a predetermined number of revolutions in a predetermined direction into contact with the uppermost surface of the substrate is used. be able to.
When a rubbing device using this rubbing roller is used, the orientation of liquid crystal molecules can be controlled by the length of the rubbing cloth pushed into the tip of the rubbing cloth, the number of rubbing, the radius of the rubbing roller, the number of rotations of the rubbing roller, and the moving speed of the substrate.

When the number of rubbings is (N), the radius of the rubbing roller is (r), the number of rotations of the rubbing roller is (m), and the moving speed of the substrate is (v), the rubbing density represented by the following equation (1): (L) is an important parameter.

[0128]

(Equation 1)

When the rubbing density is about 100 or more, the helical axis of the cholesteric liquid crystal is completely or almost completely perpendicular to the substrate surface, so that the bistable effect is easily lost as described above. When the rubbing density is 100 or less, it is considered that the entire surface of the substrate is not rubbed, and the rubbing effect is partially performed, and the helical axis of the liquid crystal is partially or almost completely formed with respect to the substrate surface. A vertical configuration is adopted, and a configuration is adopted in which a part is inclined with respect to the substrate normal. A range of about one pixel of the liquid crystal light modulation element (for example, 10
(0 μm square or more), the inclination of the helical axis of the liquid crystal has a certain angle with respect to the normal direction of the substrate as an average of the range. The same effect can be obtained even when the rubbing density of the rubbing target region corresponding to the opening of the mask layer is increased by using a partial rubbing method in which rubbing is partially performed using a mask layer or the like.

On the other hand, in the case of performing the photo-alignment treatment, when irradiating the region to be subjected to the alignment treatment with, for example, ultraviolet rays, the illuminance of the ultraviolet rays, the irradiation time, the substrate temperature at the time of irradiation, and the substrate inclination angle with respect to the ultraviolet direction at the time of irradiation. In addition, it is possible to control the alignment of liquid crystal molecules. Similar to the above-described partial alignment method (partial rubbing method), partial light alignment processing for exposing through a photomask is also effective.

Further, the outermost film material (for example,
Similar effects can be obtained when the polyimide film material) itself is made of a different material. That is, the same effect can be obtained even when a material having a different pretilt angle developed by rubbing is selected as the outermost surface material between the two substrates, or when a material having a different material configuration is selected even if the pretilt angle is the same.

As a method of partially rubbing the alignment control layer (alignment film), for example, a photoresist material is applied to the formed alignment film by spin coating or the like, and a portion to be rubbed by an existing photolithography process is used. Only after removing the resist and performing rubbing, a method of removing the resist can be used. Thereby, a rubbing area is obtained. The rubbing direction is not particularly limited.

As a method of partially performing the photo-alignment treatment,
For example, there is a method of performing ultraviolet exposure through a photomask and a polarizing plate. Thereby, a photo alignment region can be easily obtained.

FIG. 12 shows an example of a process for partially processing an alignment film by the method according to the present invention. This example includes the following steps. FIG. 12A: Substrate 2 on which electrode 12 is patterned
An insulating film 7 is formed on the surface of the electrode. FIG. 12B: An alignment film 82 is formed on the insulating film 7. FIG. 12C: Opening 73 of mask 72 with light source 70
Is exposed through the film.

Or FIG. 12C: A resist film 40 is formed on the alignment film 82, and the resist film 40 is patterned. Then, a rubbing process 64 is performed on the alignment film 82 through the opening 41 of the resist film 40. After that, the resist film 40 is removed. FIG. 12 (D): As described above, a partially processed region 16 is formed.

By the above steps, a relatively simple method can be used.
The region 16 having a desired shape can be formed at an arbitrary position.

As a method of using a heterogeneous alignment film, for example, in the step of FIG. 12C ', after patterning a resist film, a different type of alignment film is applied and baked to remove the resist film. Can be adopted.

The area 16 obtained in this manner is the same as that shown in FIG.
3A, the alignment control layers 82 and 82 in FIG. 3B are provided.
Respectively.

As described above, the surface of the substrate is subjected to the surface treatment, or the material of the outermost surface of the substrate is selected, so that the inclination of the cholesteric liquid crystal spiral axis (the angle formed with the substrate normal) is changed between the two substrates. In this case, the structure of the cholesteric domain near each substrate is different, and the light reflection characteristics in the planar state are different.

In a liquid crystal light modulation element which performs display by selective reflection of visible light by a cholesteric liquid crystal, if the inclination of the helical axis of the liquid crystal (the angle between the liquid crystal and the substrate normal) is relatively large, the light in front of the element observation side can be obtained. Although the reflectance is low, the spectrum half width is wide and the structure has excellent viewing angle characteristics. On the other hand, when the inclination of the helical axis of the liquid crystal (the angle formed with the normal to the substrate) is relatively small, a structure is adopted in which the light reflectance and color purity at the front of the element observation side are high and the viewing angle characteristics are slightly inferior. Therefore, superior brightness and color purity characteristics can be obtained in front of the device observation side while maintaining the bistable characteristics, as compared with the non-alignment-treated cholesteric liquid crystal device. Further, when the inclination of the helical axis of the liquid crystal on the element observation side (the angle formed with the substrate normal) is larger than that on the non-observation side (the side opposite to the observation side), the cholesteric domain on the side with the smaller inclination of the helical axis The reflected light is slightly scattered by the cholesteric domain on the side where the inclination of the helical axis is large, which is advantageous from the viewpoint of viewing angle characteristics.

The wavelength λ of the selectively reflected light of the light obliquely incident on the helical axis of the planar arrangement of the cholesteric liquid crystal.
Is represented by the following equation (2).

[0142]

(Equation 2)

Therefore, a liquid crystal cell having the same inclination of the spiral axis of the liquid crystal (the angle formed with the normal to the substrate) between the two substrates is manufactured, and the spectral transmittance of the liquid crystal cell is measured. It can be easily calculated by comparing the spectral transmittance measurement of the double-sided rubbing cholesteric cell with the selective reflection wavelength.

The cells subjected to high-density rubbing have a spiral axis angle of 0 °. The cell transmittance in this case is measured, and the selective reflection center wavelength is read from the obtained spectrum.

[0145]

(Equation 3)

Next, a cell having a helical axis angle of several degrees is measured, and the center wavelength is similarly read.

[0147]

(Equation 4)

By calculating the inclination of the helical axis of the liquid crystal (the angle formed with the substrate normal) by this method and comparing it with the display characteristics, the brightness and color purity of the liquid crystal light modulator having the helical axis inclination of 20 ° or less are obtained. Excellent in terms of. On the other hand, in the liquid crystal light modulation element in which the helical axis inclination of the liquid crystal is larger than 20 °, the scattering effect between domains becomes large and the color purity is inferior. When a multilayer liquid crystal light modulation device is formed, the light transmittance also decreases. Therefore, it is desirable that the inclination of the helical axis of the liquid crystal is 20 ° or less.

In the liquid crystal light modulation device of the present invention, including the liquid crystal light modulation device shown in FIG. 1, a spacer for holding the gap between the substrates as a spacer material for defining the gap is provided. It may be provided. Examples of the spacer material that defines the gap include spherical spacer particles made of glass, plastic, or the like. In addition, it is possible to use a thermoplastic or thermosetting columnar adhesive or the like. In the liquid crystal light modulation device of FIG. 1, the spacer 5 is disposed between the substrates 1 and 2 as described above.

In the liquid crystal light modulation device of the present invention, including the liquid crystal light modulation device shown in FIG. 1, a pair of substrates is supported by a structure as a space holding member in order to impart strong self-holding properties. Is also good. In the liquid crystal light modulation device of FIG. 1, a resin structure 4 is provided between substrates 1 and 2. The resin structure 4 may be, for example, a dot, such as a cylinder, a quadrangular prism, or an elliptical cylinder, arranged at regular intervals based on a predetermined arrangement rule such as a lattice arrangement. it can.

As a method of sandwiching the liquid crystal material between a pair of substrates, a generally well-known vacuum injection method and a liquid crystal dropping method can be used, and the size and cell gap of a liquid crystal cell to be manufactured are taken into consideration. The effect of the inclination of the helical axis of the liquid crystal with respect to the direction normal to the substrate does not differ depending on the method of holding the liquid crystal.

As a material for the sealing material, for example, a thermosetting or photo-curing adhesive such as an epoxy resin or an acrylic resin can be used.

When the liquid crystal light modulation device according to the present invention is driven, it is desirable to use a combination of high and low rectangular wave voltages (voltage pulses). In this case, the planar state of the cholesteric liquid crystal can be obtained by sharply turning off the voltage from the homeotropic state in which all the liquid crystal molecules are arranged in the direction of the electric field, and the focal conic state is a low voltage pulse or a planar state. It can be obtained by applying a low-voltage pulse immediately after the homeotropic state.

As a cholesteric liquid crystal light modulation element having the above characteristics, a reflection element of multicolor display is constituted by laminating a plurality of elements having different selective reflection wavelengths. In particular, by setting the selective reflection wavelength to red (R), green (G), and blue (B), a full-color display element can be obtained.

FIG. 13 shows a liquid crystal light modulation element for performing blue display,
It is a schematic sectional drawing of the laminated type liquid crystal light modulation element which laminated | stacked the three liquid crystal light modulation elements of the liquid crystal light modulation element which performs green display, and the liquid crystal light modulation element which performs red display in this order. Note that FIG.
Each liquid crystal light modulation element in the stacked liquid crystal light modulation element of
The liquid crystal light modulator is substantially the same as the liquid crystal light modulator shown in FIG. 1, and portions having basically the same configuration and operation are denoted by the same reference numerals.

Each of the liquid crystal light modulating elements B, G, and R in the laminated liquid crystal light modulating element shown in FIG. 13 shows a cholesteric phase between a pair of substrates 1 and 2 at room temperature, and has a selective reflection wavelength in a visible wavelength region. Liquid crystal materials 6b, 6g, 6
Liquid crystal layer 1 for displaying blue, green, and red including r
0b, 10g, and 10r are pinched, respectively.

The element observation side P (the side on which light is incident)
On the outer surface (back surface) of the substrate on the opposite side, if necessary,
A visible light absorbing layer is provided. In the example of FIG. 13, the visible light absorbing layer 3 is formed on the outer surface (back surface) of the substrate 2 in the liquid crystal light modulation element R.
Is provided.

In the multilayer liquid crystal light modulation device shown in FIG.
The display is performed by switching the liquid crystal 6b, 6g, 6r between the planar state (selective reflection state) and the focal conic state by applying a predetermined voltage.

In the multilayer liquid crystal light modulation device of the present invention, including the multilayer liquid crystal light modulation device shown in FIG. 13, adjacent liquid crystal light modulation devices may have a common substrate between them. FIG. 14 shows the stacked liquid crystal light modulation elements of FIG.
This shows a state where the substrates 1 and 2 between the two are shared.

In order to realize high color purity in a stacked liquid crystal light modulation device, it is important how the scattering component of light passing through each cell (each liquid crystal light modulation device) can be reduced. As described above, the light transmittance of the cell can be improved by reducing the inclination of the helical axis of the liquid crystal (the angle formed with the normal to the substrate). However, when the inclination of the helical axis is small, the viewing angle characteristic is reduced as described above. Therefore, one has a configuration in which the inclination of the helical axis is relatively small and the other has a large inclination of the helical axis. By doing so, a reflective liquid crystal light modulation element having optimal brightness, contrast, and color purity can be obtained.

When a stacked liquid crystal light modulation element is formed, the inclination of the helical axis of the liquid crystal (the angle between the liquid crystal light modulation element and the normal to the substrate) is controlled for each liquid crystal light modulation element layer. By doing this,
Further, characteristics with excellent visibility can be obtained. In other words, since the cholesteric liquid crystal domain is not a small scatterer even in the planar state, the liquid crystal light modulation element layer on the side farther from the element observation side reduces the inclination of the helical axis of the liquid crystal, and the liquid crystal light modulation layer higher than this layer. By diffusing light using the scattering effect of the element, both high color purity and high light reflectance can be achieved.

Therefore, when the B liquid crystal light modulating element, the G liquid crystal light modulating element, and the R liquid crystal light modulating element are stacked in this order from the element observation side, the B liquid crystal light modulating element-G The liquid crystal light modulation element-the R liquid crystal light modulation element, for example, in each adjacent liquid crystal light modulation element, the cholesteric of liquid crystal in the liquid crystal domain of the pixel region near the substrate on the element observation side in the liquid crystal light modulation element on the element observation side The inclination of the helical axis (the angle made with the substrate normal) is the inclination of the cholesteric helical axis of the liquid crystal in the liquid crystal domain in the pixel region near the substrate on the element observation side in the liquid crystal light modulation element on the side opposite to the element observation side (substrate method). Angle with the line)
Inclination of the cholesteric spiral axis of the liquid crystal in the liquid crystal domain in the pixel region near the substrate on the side opposite to the element observation side of the liquid crystal light modulation element on the element observation side (angle formed with the substrate normal)
Is larger than the inclination of the cholesteric helical axis of the liquid crystal in the liquid crystal domain of the pixel region near the substrate on the side opposite to the element observation side in the liquid crystal light modulation element on the side opposite to the element observation side (the angle formed with the substrate normal). This is desirable for improving the visibility of the liquid crystal light modulation element.

Further, by making the inclination of the helical axis of the liquid crystal of the liquid crystal light modulation element of each layer different between the liquid crystal light modulation elements of each layer, for example, in each of the adjacent liquid crystal light modulation elements, the liquid crystal light modulation element on the element observation side can be obtained. Of the cholesteric spiral axis of the liquid crystal in the liquid crystal domain of the pixel region near the substrate on the element observation side (the angle formed with the substrate normal) and the vicinity of the substrate on the element observation side in the liquid crystal light modulation element on the opposite side to the element observation side The inclination of the cholesteric helical axis of the liquid crystal in the liquid crystal domain of the pixel region (the angle formed with the substrate normal) is different from each other, and the pixel region near the substrate on the element observation side of the liquid crystal light modulation element opposite to the element observation side Of the cholesteric helical axis of the liquid crystal in the liquid crystal domain (angle formed with the substrate normal) and the element observation side of the liquid crystal light modulation element opposite to the element observation side By varying the inclination of the liquid crystal of the cholesteric helical axis in the liquid crystal domains of the pixel region of the substrate near the opposite (angle with respect to the substrate normal) with each other, it is possible to further increase the effect.

In the stacked liquid crystal light modulation elements shown in FIGS. 13 and 14, the liquid crystal light modulation elements B and G (G and R) adjacent to each other have the element in the liquid crystal light modulation element B (G) on the element observation side P. The angle between the cholesteric spiral axis of the liquid crystal 6b (6g) and the substrate normal in the liquid crystal domain of the pixel area X near the substrate 1a on the observation side P is opposite to the liquid crystal light modulation element G (R) on the side opposite to the element observation side P. The liquid crystal 6g (6) in the liquid crystal domain of the pixel region X near the substrate 1a on the element observation side P
r) The pixel area X in the vicinity of the substrate 2a on the liquid crystal light modulation element B (G) on the element observation side P opposite to the element observation side P, which is larger than the angle formed by the cholesteric spiral axis and the substrate normal line.
Angle between the cholesteric spiral axis of the liquid crystal 6b (6g) and the substrate normal in the liquid crystal domain of the liquid crystal light modulation element G (R) on the side opposite to the element observation side P.
The angle of the cholesteric spiral axis of the liquid crystal 6g (6r) in the liquid crystal domain of the pixel region X near the substrate 2a on the opposite side is larger than the angle formed by the substrate normal.

The adjacent liquid crystal light modulation elements B and G (G
And R), the liquid crystal light modulation element B on the element observation side P
The rubbing density of the rubbed alignment control layer in (G) is the rubbing density of the rubbed alignment control layer in the liquid crystal light modulation element G (R) opposite to the element observation side P corresponding to the rubbed alignment control layer. Less than.

According to the liquid crystal light modulating element (laminated liquid crystal light modulating element) described above, the liquid crystal layer 10 (10b, 10g, 10r) in the selective reflection state has the vicinity of the substrates 1a, 2a facing the two substrates 1, 2. When each liquid crystal domain in the pixel region X is (1), the vicinity of at least one of the substrates 1a and 2a facing the substrates 1 and 2 of the liquid crystal layer 10 (10b, 10g, and 10r) in the selective reflection state. 2
Since the liquid crystal domains in the pixel region X of a are a mixed state of a poly domain and a mono domain, the liquid crystal layer 10 (10b, 1b,
0g, 10r) near the substrates 1a, 2a facing the two substrates 1, 2
Each of the liquid crystal domains in the pixel region X of a has a polydomain structure, and the angle between the cholesteric spiral axes 61 and 62 of the liquid crystal and the substrate normal H between the liquid crystal domains in the pixel regions X of the two substrates 1a and 2a. Since θ1 and θ2 are different, a good image having high brightness, high contrast and high color purity can be displayed, and the display state (good image state having high brightness, high contrast and high color purity) can be maintained for a long time when no voltage is applied. Can be. In other words, the characteristics of high reflection intensity, high contrast, and high color purity in the planar state and bistability can both be achieved.

In order to regularly align the direction of the helical axis of the liquid crystal molecules in the focal conic state in a plane substantially parallel to the substrate surface, regions having different alignment regulating forces are provided in the alignment film (alignment control layer). Since it is provided, the light transmittance of the liquid crystal layer in the focal conic state is improved, and the contrast can be improved.

Next, an experiment for evaluating the performance of the liquid crystal light modulation device according to the present invention was conducted, and will be described below together with a comparative experiment. However, the present invention is not limited to each of these experimental examples.

In each of the experimental examples and comparative experimental examples, liquid crystal display elements having different processing conditions for the substrate (conditions for selecting an alignment control film material, rubbing processing, optical alignment processing, etc.) were manufactured, and the liquid crystal display elements were visually observed in front of the element observation side. The properties (reflectance and color purity in front of the element observation side), memory characteristics (bistability), and viewing angle characteristics (reflectance at a predetermined observation angle) were evaluated.

In each of the experimental examples and comparative experimental examples, the measurement of the inclination of the helical axis of the liquid crystal in the liquid crystal display element (the angle between the liquid crystal display element and the normal to the substrate) was carried out in a cell in which the same orientation control film was formed on the upper and lower substrates. After injecting liquid crystal into the cell, a predetermined high voltage pulse is applied to the cell into which the liquid crystal has been injected to bring the cell into a planar state, and the light transmittance of the cell in the planar state is measured. Was. At that time, the selective reflection peak wavelength was read, and the average inclination of the helical axis of the liquid crystal was calculated by the above equation (2). (Experimental conditions)-The thickness of the liquid crystal layer of the single-layer cell is all 5 µm.-The driving is pulse voltage driving using the following pulses.

A planar state is selected by a pulse of 3 ms and 80 V to 60 V, and a focal state is selected by a pulse of 3 ms and 40 V.
The conic state is selected. The stability of the memory performance is evaluated by comparing the reflection characteristic value (Y value) immediately after the application of the pulse voltage with the reflection characteristic value (Y value) after leaving the state for one month. went.・ Evaluation of viewing angle characteristics is 30 ° with respect to the normal line on the element observation side.
The light irradiation was performed from the direction of, and the detection angle with respect to the normal line on the element observation side was changed to measure the peak reflectance. The rubbing treatment includes a rubbing roller having a rubbing cloth having a predetermined tip length, moving the substrate in a predetermined direction at a predetermined speed, and rotating the substrate at a predetermined number of rotations in a predetermined direction and the substrate. A rubbing device capable of rubbing the outermost surface of the substrate by bringing the surfaces into contact with each other was used. The rubbing density was determined by the above equation (1).

In each of the experimental examples and comparative experimental examples, the reflectance, color purity, and reflection characteristic value (Y value) were measured using a reflection type spectrophotometer CM3700d (manufactured by Minolta). <Experimental Example 1> In this experiment, an example of a single-layer liquid crystal display element in which the inclination of the helical axis of the liquid crystal (the angle between the helical axis of the liquid crystal and the substrate normal in the selective reflection state) differs between the upper and lower substrates (alignment control) A liquid crystal display device in which the film material differs between the upper and lower substrates) was produced. -Alignment control film on the observation side Alignment control film material: Polyimide JALS-1024-R (manufactured by JSR) Non-rubbing Helical axis inclination (average): Approximately 18 ° Deposition conditions: Flexographic printing of alignment control film material → 80 ° C for 2 min Preliminary firing → 140 ° C for 60 min. Thickness of alignment control film: 500Å ・ Orientation control film on non-observation side (opposite to observation side) Orientation control film material: Polyimide AL1454 (manufactured by JSR) Non-rubbing Helical axis inclination (average) ): About 7 ° Film formation condition: Flexographic printing of alignment control film material → 80 ° C. for 2 minutes tentative firing → 140 ° C. for 60 minutes firing Thickness of alignment control film: 500 ° ・ Liquid crystal Liquid crystal material: Nematic liquid crystal E31-LV + Merck manufactured by Merck Chiral Agent S-811 (24.5% by weight) Selective reflection peak wavelength: λ = 550 nm Observed with a polarizing microscope It liquid crystal near the substrate in the planar state is poly domain over substantially the entire region has been confirmed in both one of the orientation control film.

In this experiment, the reflectance at the front side of the element observation side =
35% and color purity = 75%, whereby a liquid crystal display device having high visibility in front of the device observation side was obtained.

FIG. 15 shows the viewing angle characteristics of this liquid crystal display element. As shown in FIG. 15, the reflectance at the observation angle of 30 ° is 50% or more of the reflectance at the time of 0 ° observation, and it can be said that the viewing angle characteristics are sufficiently within the practical range.

When a pulse voltage was applied to bring the lens into a focal conic state, the Y value immediately after the voltage application was 1.2, and the Y value after one month was 1.3. Therefore, the liquid crystal display element of this experiment is an element excellent in memory characteristics with little change in display characteristics. <Experimental Example 2> In this experiment, another example of a single-layer liquid crystal display element in which the inclination of the helical axis of the liquid crystal (the angle between the helical axis of the liquid crystal and the substrate normal in the selective reflection state) differs between the upper and lower substrates ( A liquid crystal display device in which only the alignment control film on one substrate was rubbed was produced. -Alignment control film on the observation side Alignment control film material: Polyimide JALS-1024-R (manufactured by JSR) Non-rubbing Helical axis inclination (average): Approximately 18 ° Deposition conditions: Flexographic printing of alignment control film material → 80 ° C for 2 min Temporary baking → 140 ° C baking for 60 minutes Thickness of alignment control film: 500Å ・ Orientation control film on non-observation side Alignment control film material: Polyimide JALS-1024-R (manufactured by JSR) Rubbing over the entire area Helical axis inclination (average): approx. 4 ° Film forming condition: Flexographic printing of alignment control film material → 80 ° C for 2 minutes tentative firing → 140 ° C for 60 minutes firing Alignment control film thickness: 500 ° Rubbing conditions: Push-in tip length 0.4mm Roll radius 75mm Roll rotation speed none Substrate moving speed 30 mm / sec Number of rubbing 5 Rubbing density 5 Liquid crystal Liquid crystal material: Nematic liquid crystal E31-LV (manufactured by Merck) + Chiral agent S-811 (manufactured by Merck) (24.5% by weight) Selective reflection peak wavelength: λ = 550 nm Observed by a polarizing microscope, the liquid crystal in a planar state near the alignment control film on the observation side is observed. Are all poly domains, and it was confirmed that the liquid crystal near the alignment control film on the non-observation side was in a mixed state of poly domains and mono domains.

In this experiment, the reflectance at the front of the element observation side =
40% and color purity = 78%, and a liquid crystal display device having high visibility in front of the device observation side was obtained.

The viewing angle characteristics of this liquid crystal display device are shown in FIG.
It is shown in (plot ○). As shown in FIG. 16 (plot ○), the reflectance at an observation angle of 30 ° is 50% or more of the reflectance at an observation of 0 °, and the viewing angle characteristics can be said to be sufficiently within a practical range.

When a pulse voltage was applied to bring the lens into the focal conic state, the Y value immediately after the voltage application was 1.3, and the Y value after one month was 1.5. Therefore, the liquid crystal display element of this experiment is an element excellent in memory characteristics with little change in display characteristics. <Comparative experiment example 1> In this experiment, in the experiment example 2, the rubbing density of the polyimide film on the non-observation side was increased so that the liquid crystal in the vicinity of the polyimide film became monodomain over the entire region in the planar state. A display element was manufactured. Other than that is the same as the case of the experimental example 2, and only the points different from the case of the experimental example 2 will be described below.

Rubbing conditions: Roll rotation speed 550 rpm Rubbing frequency 2 Rubbing density Approximately 290 Helical axis inclination (average) Approximately 0 ° Observation by a polarizing microscope shows that a monodomain is formed over almost the entire region in the planar state near the orientation control film on the non-observation side. It was confirmed that there was.

The viewing angle characteristics of this liquid crystal display device are shown in FIG.
(Plot ●). As shown in FIG. 16 (plot ●), although the reflectance at the front is high, the viewing angle characteristics are inferior to those of the liquid crystal display device of Experimental Example 2, and the reflectance at an observation angle of 30 ° is 0. ° It can be seen that the reflectance is reduced to about 10% of the reflectance at the time of observation.

When a pulse voltage was applied to bring the lens into the focal conic state, the Y value immediately after the voltage application was 1.4, and the Y value after one month was 6.7. Therefore, in the liquid crystal display device of this experiment, deterioration was observed in the memory characteristics. <Comparative Experimental Example 2> In this experiment, a liquid crystal display element in which the rubbing was not performed on the polyimide film on each of the upper and lower substrates in Experimental Example 2 was produced.

FIG. 17 shows the viewing angle characteristics of this liquid crystal display element. As shown in FIG. 17, the viewing angle characteristics are sufficient, but the reflectivity in front of the element observation side is about 38% lower than that in Experimental Example 2.

As for the memory characteristics, the Y value was 1.2 immediately after the application of the voltage and after one month of storage, and no change was observed. <Experimental Example 3> In this experiment, a liquid crystal display element in which the rubbing density of the polyimide film was slightly higher on the non-observation side (the rubbing density was 10) was produced. The helical axis inclination (average) was about 4 °. Observation with a polarizing microscope confirmed that the liquid crystal near the alignment control film on the non-observation side was in a planar state and was a mixed state of polydomains and monodomains.

The viewing angle characteristics of this liquid crystal display device are shown in FIG.
It is shown in (plot ○). The plot ● in FIG. 18 indicates the result of Experimental Example 2. As shown in FIG. 18, the viewing angle characteristics were almost the same as in the case of Experimental Example 2. Experimental Example 2 for frontal reflectance, color purity, and long-term memory characteristics
And the same results were obtained. <Experimental Example 4> In this experiment, still another example of a single-layer liquid crystal display device in which the inclination of the helical axis of the liquid crystal (the angle between the helical axis of the liquid crystal and the substrate normal in the selective reflection state) differs between the upper and lower substrates. (Liquid crystal display device in which only one alignment control film on one substrate was subjected to photo-alignment treatment) was produced. -Alignment control film on the observation side Alignment control film material: Polyimide TT-054 (manufactured by Hitachi Chemical) Non-rubbing Helical axis inclination (average): Approximately 16 ° Deposition conditions: Flexographic printing of the alignment control film material → 100 ° C for 1 minute → Bake at 230 ° C for 30 min. Thickness of alignment control film: 500 ・ Alignment control film on non-observation side Alignment control film material: Polyimide TT-054 (manufactured by Hitachi Chemical) Optical alignment treatment Helical axis inclination (average): about 6 ° Conditions: Flexographic printing of alignment control film material → 100 ° C. for 1 minute tentative firing → 230 ° C. for 30 minutes Thickness of alignment control film: 500 ° UV irradiation condition: 5 J / cm ² Irradiation angle 15 ° Substrate temperature 23 ° C. Using a polarizing plate Liquid crystal liquid crystal material: Nematic liquid crystal E31-LV manufactured by Merck + Chiral agent S-811 manufactured by Merck (24.5) %) Selective reflection peak wavelength: λ = 550 nm In observation with a polarizing microscope, all liquid crystals in the planar state near the alignment control film on the observation side are polydomains, and the liquid crystal near the alignment control film on the non-observation side is polydomain. It was confirmed that the mono domains were mixed.

In this experiment, the reflectance on the front side of the element observation side =
As a result, a liquid crystal display device having high visibility in front of the device observation side was obtained.

Although the viewing angle characteristics of this liquid crystal display element are not shown, the reflectivity at an observation angle of 30 ° is 20%.
The reflectance at the time of 0 ° observation is 50% or more, and it can be said that the viewing angle characteristics are sufficiently within the practical range.

When a pulse voltage was applied to bring the lens into a focal conic state, the Y value immediately after the voltage application was 1.3, and the Y value after one month of standing was 1.4. Therefore, the liquid crystal display element of this experiment is an element excellent in memory characteristics with little change in display characteristics. <Experimental Example 5> In this experiment, still another example of a single-layer liquid crystal display device in which the inclination of the helical axis of the liquid crystal (the angle between the helical axis of the liquid crystal and the substrate normal in the selective reflection state) differs between the upper and lower substrates. (A liquid crystal display element in which the alignment control films on both substrates were subjected to photo-alignment treatment and the exposure amounts differed in the both-side photo-alignment treatment) was prepared. -Alignment control film on the observation side Alignment control film material: polyimide TT-054 (manufactured by Hitachi Chemical) Optical alignment treatment Helical axis inclination (average): about 12 ° Film formation conditions: Flexographic printing of alignment control film material → 100 ° C for 1 min Firing → 230 ° C for 30 min Firing thickness of alignment control film: 500 ° Irradiation condition: ² J / cm ² Irradiation angle 15 ° Substrate temperature 23 ° C Irradiate the entire surface of the substrate using a polarizing plate ・ Alignment control film on non-observation side Alignment control Film material: polyimide TT-054 (manufactured by Hitachi Chemical) Optical alignment treatment Spiral axis inclination (average): about 6 ° Film formation conditions: Flexographic printing of alignment control film material → 100 ° C for 1 min tentative firing → 230 ° C for 30 min firing Alignment control film Film thickness: 500 ° Irradiation condition: 5 J / cm ² Irradiation angle 15 ° Substrate temperature 23 ° C. Irradiate the entire surface of the substrate using a polarizing plate ・ Liquid crystal Liquid crystal material: Mel Nematic liquid crystal E31-LV (manufactured by Merck) + Chiral agent S-811 (manufactured by Merck) (24.5% by weight) Selective reflection peak wavelength: λ = 550 nm Observation with a polarizing microscope revealed that the liquid crystal near any alignment control film was monodomain. And polydomains were confirmed to be mixed.

In this experiment, the reflectance at the front of the element observation side =
41% and color purity = 80%, thus obtaining a liquid crystal display element having high visibility in front of the element observation side.

Although the viewing angle characteristics of this liquid crystal display element are not shown, the reflectance at an observation angle of 30 ° is 21%.
The reflectance at the time of 0 ° observation is 50% or more, and it can be said that the viewing angle characteristics are sufficiently within the practical range.

When a pulse voltage was applied to bring the lens into the focal conic state, the Y value immediately after the voltage application was 1.2, and the Y value after one month of standing was 1.4. Therefore, the liquid crystal display element of this experiment is an element excellent in memory characteristics with little change in display characteristics. <Experimental Example 6> In this experiment, still another example of a single-layer liquid crystal display device in which the inclination of the helical axis of the liquid crystal (the angle between the helical axis of the liquid crystal and the substrate normal in the selective reflection state) differs between the upper and lower substrates. (A liquid crystal display element in which the alignment control films on both substrates were subjected to photo-alignment treatment and the substrate temperatures during exposure differed in the both-side photo-alignment treatment) was prepared. -Alignment control film on the observation side Alignment control film material: polyimide TT-054 (manufactured by Hitachi Chemical) Optical alignment treatment Helical axis inclination (average): about 12 ° Film formation conditions: Flexographic printing of alignment control film material → 100 ° C for 1 min Firing → 230 ° C for 30 min Firing thickness of alignment control film: 500 ° Irradiation condition: ² J / cm ² Irradiation angle 15 ° Substrate temperature 23 ° C Irradiate the entire surface of the substrate using a polarizing plate ・ Alignment control film on non-observation side Alignment control Film material: Polyimide TT-054 (manufactured by Hitachi Chemical) Optical alignment treatment Helical axis inclination (average): about 7 ° Film formation conditions: Flexographic printing of alignment control film material → 100 ° C for 1 min tentative firing → 230 ° C for 30 min firing Alignment control film Film thickness: 500 ° Irradiation condition: ² J / cm ² Irradiation angle 15 ° Substrate temperature 120 ° C. Irradiate the entire surface of the substrate using a polarizing plate ・ Liquid crystal Liquid crystal material: Nematic liquid crystal E31-LV manufactured by LUC + Chiral agent S-811 manufactured by Merck (24.5% by weight) Selective reflection peak wavelength: λ = 550 nm Observation with a polarizing microscope revealed that both liquid crystals near any alignment control film were monodomain. And polydomains were confirmed to be mixed.

In this experiment, the reflectance at the front side of the element observation side =
40% and color purity = 77%, and a liquid crystal display device having high visibility in front of the device observation side was obtained.

Although the viewing angle characteristics of this liquid crystal display element are not shown, the reflectivity at an observation angle of 30 ° is 21%.
The reflectance at the time of 0 ° observation is 50% or more, and it can be said that the viewing angle characteristics are sufficiently within the practical range.

When a pulse voltage was applied to bring the lens into the focal conic state, the Y value immediately after the voltage application was 1.3, and the Y value after one month was 1.5. Therefore, the liquid crystal display element of this experiment is an element excellent in memory characteristics with little change in display characteristics. <Experimental Example 7> In this experiment, still another example of a single-layer liquid crystal display element in which the inclination of the helical axis of the liquid crystal (the angle between the helical axis of the liquid crystal and the substrate normal in the selective reflection state) differs between the upper and lower substrates. (Liquid crystal display device in which only the alignment control film on one substrate was partially rubbed) was produced. -Alignment control film on the observation side Alignment control film material: Polyimide JALS-1024-R (manufactured by JSR) Non-rubbing Helical axis inclination (average): Approximately 18 ° Deposition conditions: Flexographic printing of alignment control film material → 80 ° C for 2 min Preliminary baking → 140 ° C baking for 60 minutes Thickness of alignment control film: 500Å ・ Alignment control film on non-observation side Alignment control film material: Polyimide JALS-1024-R (manufactured by JSR) Partial rubbing using the following resist pattern Inclination (average): about 7 ° Film formation conditions: Flexographic printing of alignment control film material → 80 ° C for 2 minutes tentative firing → 140 ° C for 60 minutes firing Alignment control film thickness: 500 ° Resist pattern Photomask: oblique light / opening = 7 μm / 3 μm (pitch 10 μm) Spin coating: OFPR-800 (manufactured by Tokyo Ohka) Prebaking: 80 ° C. 15 min clean oven Exposure: 30 mJ / cm ² UV exposure device Development: SD-1 (manufactured by Tokuyama, developer) Rinse: ultrapure running water Post bake: 120 ° C., 15 min Etching: salt iron solution D (manufactured by Hayashi Junyaku), 20 min Resist peeling: isopropyl alcohol (IPA: manufactured by Tokuyama) Peeling time: 2 min Rubbing conditions: Push-in length of 0.4 mm Roll radius 75 mm Roll rotation speed 900 rpm Substrate moving speed 30 mm / sec Number of rubbing times 2 Rubbing density About 470 ・ Liquid crystal Liquid crystal material : Nematic liquid crystal E31-LV manufactured by Merck + Chiral agent S-811 manufactured by Merck (24.5% by weight) Selective reflection peak wavelength: λ = 550 nm Observed by a polarizing microscope, in a planar state near the alignment control film on the observation side. All liquid crystals are polydomain , It was confirmed liquid crystal alignment layer near the non-viewing side is mixed state of all poly domain and monodomain.

In this experiment, the reflectance at the front of the element observation side =
39% and color purity = 72%, and a liquid crystal display device having high visibility in front of the device observation side was obtained.

Although the viewing angle characteristics of this liquid crystal display element are not shown, the reflectance at an observation angle of 30 ° is 21%.
The reflectance at the time of 0 ° observation is 50% or more, and it can be said that the viewing angle characteristics are sufficiently within the practical range.

When a pulse voltage was applied to bring the lens into the focal conic state, the Y value immediately after the voltage application was 1.3, and the Y value after one month was 1.4. Therefore, the liquid crystal display element of this experiment is an element excellent in memory characteristics with little change in display characteristics. In the focal conic state, a very high transmittance of about 80% was obtained. <Experimental Example 8> In this experiment, a plurality of single-layer liquid crystal display elements having different inclinations of the helical axis of the liquid crystal between the upper and lower substrates (the angle between the helical axis of the liquid crystal and the substrate normal in the selective reflection state) are stacked. An example of a liquid crystal display element (a stacked liquid crystal display element in which the angle formed by the helical axis of the liquid crystal in the selective reflection state with respect to the substrate normal in each element is different from each other) was produced.・ Substrate Substrate material: Polycarbonate substrate with ITO Thickness: 0.1 mm thick ・ Liquid crystal (selection of liquid crystal composition by changing the amount of chiral material added to nematic liquid crystal and adjusted peak wavelength of reflection) Red display (R) element: Adjusted so that the selective reflection peak wavelength λ = 680 nm Cell gap 9 μm Green element (G) element: Adjusted so that the selective reflection peak wavelength λ = 550 nm Cell gap 5 μm Blue element (B) element: Selective reflection peak wavelength λ = Adjusted to 480 nm. Cell gap 5 μm. Note that the lowest surface (R
A black absorbing layer was disposed on the bottom surface of the substrate of the device).

For the orientation control film, the same combination of materials as in Example 1 was used for the liquid crystal display element of each layer, and the inclination of the helical axis on the observation side was larger than that on the non-observation side in each element without rubbing. It was arranged so that it might become. The effect of the tilt angle of the helical axis of the liquid crystal (the angle between the helical axis of the liquid crystal and the substrate normal in the selective reflection state) differs depending on the helical pitch of the cholesteric liquid crystal. The larger the helical pitch, the smaller the tilt angle. The measured values of the inclination angles of the R, G, and B layers in the liquid crystal display device are as follows.

R liquid crystal display element: observation side 16 °, non-observation side 5 ° G liquid crystal display element: observation side 18 °, non-observation side 7 ° B liquid crystal display element: observation side 20 °, non-observation side 8 ° tilt angle Is equivalent between the upper and lower substrates (18 ° ~
Compared to a liquid crystal display element in which a liquid crystal display element of about 20 ° is stacked, in a multilayer liquid crystal display element in which liquid crystal display elements having different inclination angles between upper and lower substrates are stacked, the color purity of the liquid crystal display element in each layer And the transmittance of the element is also improved. Therefore, the color purity of the stacked liquid crystal display element in which the liquid crystal display elements having different inclination angles between the upper and lower substrates are improved.

The chromaticity diagram of the display image by the multi-layer liquid crystal display device in this experiment and the three-layer liquid crystal display device use the same material for the alignment control films on both substrates (JALS-1024, manufactured by JSR Corporation).
FIG. 19 shows a chromaticity diagram of a display image of the multilayer liquid crystal display element (comparative example) formed by R) and not subjected to rubbing. The solid line in FIG. 19 is a chromaticity diagram of a display image by the liquid crystal display device of this experimental example, and the dotted line is a chromaticity diagram of a display image by the liquid crystal display device of the comparative example. As shown in FIG. 19, it can be seen that the expressible color range of the multilayer liquid crystal display element of this experimental example is expanded. <Experimental Example 9> In this experiment, another example of a multilayer liquid crystal display element (a multilayer liquid crystal display element in which the rubbing densities of the rubbed alignment control films in each element are different from each other) was manufactured.・ Substrate Substrate material: Polycarbonate substrate with ITO Thickness: 0.1 mm thick ・ Liquid crystal (selection of liquid crystal composition by changing the amount of chiral material added to nematic liquid crystal and adjusted peak wavelength of reflection) Red display (R) element: Adjusted so that the selective reflection peak wavelength λ = 680 nm Cell gap 9 μm Green element (G) element: Adjusted so that the selective reflection peak wavelength λ = 550 nm Cell gap 5 μm Blue element (B) element: Selective reflection peak wavelength λ = Adjusted to 480 nm. Cell gap: 5 μm. Note that a black absorbing layer was disposed on the lowest surface (the bottom surface of the substrate of the R element) of each of the R, G, and B liquid crystal display elements after lamination. -Alignment control film: polyimide JALS-1024-R (manufactured by JSR) The same alignment control film is used for the liquid crystal display element of each layer between the upper and lower substrates, and the alignment control film of the observation side is rubbed for the liquid crystal display element of each layer. Was performed, the rubbing treatment was performed on the orientation control film on the non-observation side. The rubbing density is controlled by the number of rubbings (N in the above formula (1)), 10 for the non-observation side alignment control film of the R liquid crystal display element, 5 for the non-observation side alignment control film of the G liquid crystal display element, and B for the non-observation side alignment control film. The non-observation side alignment control film of the liquid crystal display element was set to 3. The measured values of the inclination angles of the R, G, and B layers in the liquid crystal display element (the angles formed by the liquid crystal helical axis and the substrate normal in the selective reflection state) are as follows.

R liquid crystal display element: observation side 16 °, non-observation side 3 ° G liquid crystal display element: observation side 18 °, non-observation side 4 ° B liquid crystal display element: observation side 20 °, non-observation side 6 ° tilt angle Is equivalent between the upper and lower substrates (18 to 2 for each of the upper and lower substrates).
Compared to a multi-layer liquid crystal display element in which liquid crystal display elements of about 0 ° are stacked, a multi-layer liquid crystal display element in which liquid crystal display elements having different inclination angles between the upper and lower substrates is stacked has a higher color purity of the liquid crystal display element in each layer. And the transmittance of the element is also improved. Therefore, the color purity of the stacked liquid crystal display element in which the liquid crystal display elements having different inclination angles between the upper and lower substrates are improved.

FIG. 20 shows a chromaticity diagram of a display image by the multi-layer liquid crystal display element of this experiment. As shown in FIG. 20, as in the case of FIG. 19, it can be seen that the expressible color range of the multilayer liquid crystal display element of this experimental example is expanded.

Next, a liquid crystal light modulating element provided with regions having different alignment controlling forces in order to regularly align the direction of the helical axis of the liquid crystal molecules in the focal conic state in a plane substantially parallel to the substrate surface. An experiment was performed, which will be described below. <Experimental example 10> In this experimental example, a rubbing treatment is performed on the alignment control film.

Using two glass substrates with ITO (manufactured by Central Glass), ITO of each substrate was patterned into a band shape by a photolithography method (electrode width: 300 μm, pitch: 350 μm).

Next, an insulating film was formed by applying and baking an insulating material on each of the ITO-formed surfaces of both substrates. Then, a polyimide material (J
SR-AL-8044) was applied and calcined at 80 ° C for 2 minutes. Further, by firing at 160 ° C. for 60 minutes, an alignment control film was formed.

Next, a positive resist (OFPR-800 manufactured by Tokyo Ohka Co., Ltd.) was spin-coated on the orientation control film forming surface of one of the substrates, and prebaked at 80 ° C. for 15 minutes using a clean oven. did.

Then, using a photomask in which strip-shaped openings (width 4 μm) were formed at a pitch of 10 μm, exposure was performed at 30 mJ / cm ² using an ultraviolet exposure apparatus. next,
Developing was performed using a developing solution (SD-1 manufactured by Tokuyama Corporation), and unnecessary parts were removed by rinsing with running ultrapure water. Thereafter, post-baking was performed at 120 ° C. for 15 minutes. Thus, a mask layer for the next rubbing treatment was formed.

Next, a rubbing treatment was performed on the substrate on which the mask layer was formed. The rubbing treatment was carried out using a flocking roll having a tip indentation length of 0.4 mm and a roll radius of 75 mm, a roll rotation speed of 900 rpm, and a substrate moving speed of 30 m.
The rubbing was performed twice from above the mask layer under the condition of m / sec. The rubbing density was about 470, and the helical axis inclination (average) was about 5 °.

After the rubbing treatment, the mask layer was removed by removing the resist using isopropyl alcohol (IPA) for 2 minutes. Then, 5 is placed on the rubbed substrate.
μm spacer (Micropearl SP205 manufactured by Sekisui Chemical Co., Ltd.)
0 μm), and a sealant (XN21S manufactured by Mitsui Chemicals, Inc.) was formed while leaving a liquid crystal injection port on the other substrate, and then both substrates were attached to each other to produce an empty cell.

As a liquid crystal composition, a nematic liquid crystal E-31LV manufactured by Merck and a chiral agent S-8 manufactured by Merck were used.
11 was added at 24.5 wt%, and a chiral nematic liquid crystal in which the peak wavelength of selective reflection was adjusted to λ = 550 nm was used. The helical pitch of the liquid crystal composition was about 343 nm. Then, this liquid crystal composition was injected into the cell by a vacuum injection method. Finally, the liquid crystal injection port was sealed with a sealant to obtain a liquid crystal light modulation element.

After a voltage was applied to the thus obtained liquid crystal light modulation element to bring it into a focal conic state, the characteristics of the element were evaluated. The evaluation was performed by using a spectrophotometer (Hitachi) and measuring the transmittance away from the integrating sphere. As a result, the transmittance of the device was about 80%. For comparison,
When a liquid crystal display device was manufactured in the same procedure as in Experimental Example 10 except that rubbing was not performed, the transmittance of the device in the focal conic state was about 62%.

When the width and arrangement pitch of the rubbing portion were variously changed and the effects thereof were examined, these values were too large or too small, and the range described above (that is, the width of the region having a different alignment regulating force was changed to W. When the helical pitch of the liquid crystal is p, p <W <20p, when the arrangement pitch of the regions having different alignment regulating forces is L, and when the helical pitch of the liquid crystal is p, 5p <L <
If it exceeds 100 p), the transmittance tends to decrease.

Further, when the arrangement pitch of the rubbing processing section was changed between a uniform arrangement and a random arrangement, and the effect was examined, the transmittance showed the same value but the arrangement pitch was uniform. In the sample, diffracted light was observed at a specific angle, and the visibility was likely to be reduced.

Further, when the arrangement direction of the rubbing processing section and the pixel arrangement direction were variously changed and the influence thereof was examined, the transmittances showed the same value in all cases. And the display quality tended to deteriorate due to moiré.

When the influence of the rubbing processing portion was changed to a linear shape and a V-shape, and the effect was examined, the transmittance was equal in all cases. Is linear, the visibility tends to be different between when viewed from the same direction as the arrangement direction of the rubbing portions and when viewed from the vertical direction.

In comparison with the case where no rubbing treatment was performed, no significant change was observed in the memory characteristics, while it was confirmed that the viewing angle characteristics were 50% or more and the front reflectance increased. . <Experimental example 11> In this experimental example, a photo-alignment treatment is performed on the alignment control film.

Using two glass substrates with ITO (manufactured by Central Glass), ITO of each substrate was patterned into a band shape by the photolithography method (electrode width: 300 μm, pitch: 350 μm).

Next, a polysilazane solution L120 (manufactured by Tonen Co., Ltd.) was used on each of the ITO-formed surfaces of both substrates, and a thin film having a thickness of 1000 ° was formed on the electrode surfaces of both substrates by a spin coating method. In an oven at 90 ° C. and a humidity of 85% for 3 hours to form an insulating film. Then, a polyimide material (HT-054 manufactured by Hitachi Chemical Co., Ltd.) was used at 3000 rpm,
Spin coating was performed for 30 seconds and calcined at 100 ° C. for 1 minute. Further, by firing at 230 ° C. for 30 minutes, an orientation control film was formed.

Then, 5 J / c was applied to the orientation control film of one of the substrates by an ultraviolet irradiation device through a polarizing plate and a photomask in which an opening similar to that of Experimental Example 10 was formed.
Light irradiation was performed at an irradiation angle of 15 ° at m ² , and a photo-alignment treatment was partially performed. The helical axis inclination (average) was about 7 °.

Thereafter, in the same manner as in Experimental Example 10, spacers were sprayed, a sealant was formed, the substrates were bonded, and liquid crystal was injected to produce a liquid crystal light modulation element.

After a voltage was applied to the obtained liquid crystal light modulation element to make it into a focal conic state, the measurement was performed in the same manner as in Experimental Example 10, and the transmittance was about 80%.

When the width or arrangement pitch of the photo-alignment processing section is too large or too small and exceeds the range described above, the transmittance tends to decrease. Then, the transmittance is the same, but the visibility tends to be reduced due to the influence of the diffracted light, and the transmittance is the same when the arrangement direction of the light alignment processing unit is the same as the pixel arrangement direction. , The display quality tends to deteriorate due to the effect of moiré, and the transmittance is the same when the alignment of the optical alignment processing unit is aligned, but is observed from the same direction as the arrangement and from the vertical direction. The point that the visibility is likely to be different from that in the case of the experiment was the same as in the experimental example 10.

In comparison with the case where the photo-alignment treatment was not performed, no significant change was observed in the memory characteristics. On the other hand, it was confirmed that the viewing angle characteristics were maintained at 50% or more and the front reflectance increased. Was.

[0223]

As described above, according to the present invention, a liquid crystal having a cholesteric phase between a pair of substrates at room temperature and containing a liquid crystal layer containing a liquid crystal material having a selective reflection wavelength peak in a visible wavelength region is sandwiched. A light modulation element, which is bright,
A liquid crystal light modulation element having good contrast and color purity and excellent bistability can be provided.

Further, according to the present invention, there is provided a multi-layer liquid crystal display device in which a plurality of liquid crystal layers each sandwiched between a pair of substrates are laminated, which is bright, has good contrast and color purity, and has bistability. It is possible to provide a laminated liquid crystal light modulation element having excellent characteristics.

According to the present invention, there is also provided a method for manufacturing a liquid crystal light modulation element in which a liquid crystal layer containing a liquid crystal material exhibiting a cholesteric phase at room temperature and having a selective reflection wavelength peak in a visible wavelength region is sandwiched between a pair of substrates. In addition, it is possible to provide a method for manufacturing a liquid crystal light modulation element that can obtain a liquid crystal light modulation element that is bright, has good contrast and color purity, and has excellent bistability.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an example of a liquid crystal light modulation device according to the present invention.

FIG. 2 is a schematic plan view of a pixel pattern of the liquid crystal light modulation device shown in FIG.

FIG. 3A shows a liquid crystal layer in a selective reflection state of the liquid crystal light modulation device shown in FIG. 1, in which a liquid crystal domain in a pixel region near at least one of the substrates near both substrates is a poly domain; FIG. 2B is a diagram showing a mixed state of monodomains, and FIG. 1B is a diagram showing a state in which the liquid crystal light modulation element shown in FIG. FIG. 3 is a diagram showing a state where a domain structure is formed and angles formed by cholesteric helical axes of liquid crystals and substrate normals are different in each liquid crystal domain in a pixel region near both substrates.

FIG. 4 is a diagram showing a state in which a projection-like structure having a rib structure, which is an example of an alignment control unit, is formed in the liquid crystal light modulation device shown in FIG.

FIG. 5 is a view showing a state in which equipotential lines cause distortion near the protruding structure in a liquid crystal light modulation element having a protruding structure having a rib structure.

FIG. 6 is a diagram showing a state in which the direction of an electric field is partially inclined in a specific direction in a liquid crystal light modulation device in which a rib-shaped protrusion is formed.

FIG. 7 is a view showing a state in which spiral axes of liquid crystals are regularly aligned in a plane substantially parallel to the substrate.

8 is a diagram showing a state when the liquid crystal light modulation element is viewed from above in the state shown in FIG. 7;

9 is a diagram showing a state in which a groove (slit), which is another example of the arrangement regulating means, is formed in the electrode of the liquid crystal light modulation device shown in FIG.

FIG. 10 is a diagram showing a state in which equipotential lines are distorted in the vicinity of the slit in a liquid crystal light modulation element in which a slit is formed in an electrode.

11 is a diagram showing an example in which a partially processed region is provided on an alignment control layer (alignment film) in the liquid crystal light modulation device shown in FIG.

FIG. 12 is a view showing one example of a part of the manufacturing process of the liquid crystal light modulation device according to the present invention, and FIG. 12 (A) shows a process of forming an insulating film on an electrode surface of a substrate on which electrodes are patterned; (B) is a step of forming an alignment film on the insulating film, FIG. (C) is a step of exposing the alignment film through a mask opening by a light source, and FIG. (C ′) is a step of forming a resist film on the alignment film. Forming, patterning the resist film, and rubbing the alignment film through the opening of the resist film, and FIG. 3D shows the step of removing the resist film to obtain a partially processed region. It is.

FIG. 13 is a schematic diagram of a stacked liquid crystal light modulation element in which three liquid crystal light modulation elements, a liquid crystal light modulation element for performing blue display, a liquid crystal light modulation element for performing green display, and a liquid crystal light modulation element for performing red display, are stacked in this order. It is sectional drawing.

FIG. 14 is a view showing a state in which a substrate between the adjacent liquid crystal display elements is shared in the stacked liquid crystal light modulation element of FIG.

FIG. 15 is a view showing the viewing angle characteristics of the liquid crystal light modulation device obtained in Experimental Example 1.

FIG. 16 is a view showing the viewing angle characteristics of the liquid crystal light modulation elements obtained in Experimental Example 2 and Comparative Experimental Example 1.

FIG. 17 is a view showing the viewing angle characteristics of the liquid crystal light modulation device obtained in Comparative Experimental Example 2.

FIG. 18 is a view showing viewing angle characteristics of the liquid crystal light modulation devices obtained in Experimental Examples 3 and 2.

FIG. 19 is a chromaticity diagram of a display image obtained by the liquid crystal display device obtained in Experimental Example 8, and a liquid crystal display device in which the alignment control films on both substrates are non-rubbed for both liquid crystal display devices (comparative example)
FIG. 6 is a chromaticity diagram of a display image according to FIG.

FIG. 20 is a chromaticity diagram of a display image obtained by the liquid crystal display device obtained in Experimental Example 9.

FIG. 21 is a schematic diagram showing a direction of a helical axis of each liquid crystal domain in a focal conic state in a conventional liquid crystal element.

[Explanation of symbols]

1, 2 A pair of substrates 1a Near the substrate facing both substrates 1 2a Near the substrate facing both substrates 3 Light absorbing layer 4 Resin structure 5 Spacer 6, 6b, 6g, 6r Liquid crystal composition 7 Insulating film 10, 10b, 10g Reference Signs List 10r Liquid crystal layer 11, 12 Transparent electrode 13 Protruding structure having rib structure 15 Slit 16 Partially processed region 26 Equipotential line 40 Resist film 41 Opening of resist film 40 60 Liquid crystal molecules 61, 62 Cholesteric spiral axis 64 Rubbing treatment 70 Light source 72 Mask 73 Opening 81, 82 Alignment control layer B, G, R Liquid crystal display element E Electric field direction F Spiral axis direction H Substrate normal M Mono domain P Element observation side S Seal material X Pixel area θ1 The angle formed between the cholesteric spiral shaft 61 and the substrate normal H θ2 The angle formed between the cholesteric spiral shaft 62 and the substrate normal H

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mika Miyai 2-3-1-3 Azuchicho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka International Building Minolta Co., Ltd. 2H088 GA03 HA03 JA14 MA05 2H089 HA32 QA16 RA05 RA10 RA11 TA04 2H090 HB08Y HC05 LA09 MA10 MB01 MB12 MB13

Claims (38)

[Claims] 1. A liquid crystal light modulation device comprising a pair of substrates sandwiching a liquid crystal layer containing a liquid crystal material exhibiting a cholesteric phase at room temperature and having a selective reflection wavelength peak in a visible wavelength range, wherein A liquid crystal light modulation device, wherein a liquid crystal domain in a pixel region of a liquid crystal layer near at least one of the substrates facing the two substrates has a mixed state of a poly domain and a mono domain. 2. In a selective reflection state, each liquid crystal domain in a pixel region near both substrates is in the mixed state, and a poly domain and a mono domain mixed between liquid crystal domains in a pixel region near both substrates are included. 2. The liquid crystal light modulation device according to claim 1, wherein the ratio is different. 3. The liquid crystal domain having a higher polydomain ratio among the liquid crystal domains in the pixel regions near the two substrates in the selective reflection state is the liquid crystal domain in the pixel region near the substrate on the element observation side. Liquid crystal light modulator. 4. A liquid crystal display according to claim 1, wherein, in the selective reflection state, one of the liquid crystal domains in the pixel regions near the two substrates is in the mixed state, and the other liquid crystal domain is composed of only the poly domains. Liquid crystal light modulator. 5. The liquid crystal domain in the pixel region near the two substrates in the selective reflection state, wherein the liquid crystal domain composed of only the poly domains is the liquid crystal domain in the pixel region near the substrate on the element observation side. Liquid crystal light modulator. 6. An alignment control layer which is in contact with liquid crystal is provided on at least a side of the pair of substrates facing the liquid crystal domains in the mixed state, the substrate facing the liquid crystal domains in the mixed state, and the mixed state in the selective reflection state is provided. 6. The liquid crystal light modulation device according to claim 1, wherein the liquid crystal molecules are controlled in alignment by the alignment control layer. 7. The liquid crystal light modulation device according to claim 6, wherein the alignment control is performed by rubbing an alignment control layer provided on a substrate facing the mixed liquid crystal domains. 8. The liquid crystal light modulation element according to claim 7, wherein the rubbed alignment control layer has a rubbing density of 10 or less. 9. The liquid crystal light modulation device according to claim 6, wherein the alignment control is performed by applying predetermined light irradiation to an alignment control layer provided on a substrate facing the mixed liquid crystal domains. 10. The liquid crystal light modulation device according to claim 9, wherein the alignment control is determined by an irradiation amount of the predetermined light to the alignment control layer. 11. The liquid crystal light modulation device according to claim 9, wherein the alignment control is determined by a substrate temperature at the time of irradiating the alignment control layer with the predetermined light. 12. The liquid crystal light modulation device according to claim 9, wherein said alignment control is determined by a light irradiation angle with respect to a substrate surface when said predetermined light is irradiated on said alignment control layer. 13. The liquid crystal light modulation device according to claim 9, wherein said predetermined light is ultraviolet light. 14. A liquid crystal light modulating element comprising a liquid crystal layer sandwiched between a pair of substrates, the liquid crystal layer exhibiting a cholesteric phase at room temperature and having a peak of a selective reflection wavelength in a visible wavelength range. Each liquid crystal domain in the pixel region near the substrate facing the two substrates of the liquid crystal layer has a polydomain structure, and the angle between the liquid crystal domains in the pixel region near both substrates and the substrate normal of the cholesteric spiral axis of the liquid crystal. A liquid crystal light modulation element characterized in that: 15. In the selective reflection state, an angle between the cholesteric spiral axis of the liquid crystal and the substrate normal in the liquid crystal domain of the pixel region near the substrate on the element observation side among the liquid crystal domains in the pixel region near the two substrates is on the opposite side. The angle of the cholesteric spiral axis of the liquid crystal in the liquid crystal domain of the pixel region near the substrate is larger than the angle formed by the substrate normal.
The liquid crystal light modulation device as described in the above. 16. An alignment control layer in contact with a liquid crystal is provided on a side of the pair of substrates facing the liquid crystal layer, respectively.
16. The liquid crystal light modulation device according to claim 14, wherein in the selective reflection state, an angle between a cholesteric spiral axis of liquid crystal and a substrate normal in each liquid crystal domain of a pixel region near both substrates is controlled by the alignment control layer. 17. An angle between a liquid crystal domain in a pixel region near both substrates in a selective reflection state and a cholesteric helical axis of a liquid crystal with respect to a substrate normal depends on an orientation control layer provided on both substrates. 17. The liquid crystal light modulation device according to claim 16, which is caused by rubbing at least one of the alignment control layers. 18. The liquid crystal light modulation device according to claim 17, wherein a rubbing density of the rubbed alignment control layer is 10 or less. 19. In the selective reflection state, the angle of the cholesteric spiral axis of the liquid crystal between the liquid crystal domains in the pixel region near the two substrates and the substrate normal is determined by the angle of the alignment control layers provided on the two substrates. 17. The liquid crystal light modulation element according to claim 16, wherein the liquid crystal light modulation element is generated when at least one of the alignment control layers is irradiated with predetermined light. 20. In the selective reflection state, the angle of the cholesteric helical axis of the liquid crystal between the liquid crystal domains in the pixel region near the two substrates and the substrate normal depends on the irradiation amount of the predetermined light to the alignment control layer. 20. The liquid crystal light modulation device according to claim 19, which is controlled. 21. In the selective reflection state, the angle of the cholesteric helical axis of the liquid crystal between the liquid crystal domains in the pixel region near the two substrates and the substrate normal is determined when the predetermined light is irradiated onto the alignment control layer. The liquid crystal light modulation device according to claim 19, wherein the liquid crystal light modulation device is controlled by a substrate temperature. 22. In the selective reflection state, the angle of the cholesteric helical axis of the liquid crystal between the liquid crystal domains in the pixel region near the two substrates and the normal to the substrate depends on the irradiation of the predetermined light on the alignment control layer. The liquid crystal light modulation device according to claim 19, wherein the liquid crystal light modulation device is controlled by a light irradiation angle with respect to a substrate surface. 23. The liquid crystal light modulation device according to claim 19, wherein the predetermined light is ultraviolet light. 24. The liquid crystal light modulation device according to claim 16, wherein the alignment control layers provided on the two substrates have different material parameters from each other. 25. The liquid crystal display according to claim 1, wherein in the selective reflection state, the angle between the cholesteric spiral axis of the liquid crystal and the substrate normal in each of the liquid crystal domains in the pixel region near both substrates is 20 ° or less. A liquid crystal light modulation device according to any one of the above. 26. A multi-layer liquid crystal light modulation device comprising a plurality of liquid crystal layers each sandwiched between a pair of substrates, wherein at least one liquid crystal layer of the plurality of liquid crystal layers is
26. A multilayer liquid crystal light modulation device comprising a liquid crystal light modulation device according to any one of claims 1 to 6, 9 to 16, and 19 to 25 together with a pair of substrates sandwiching the liquid crystal layer. 27. In each of the adjacent liquid crystal light modulation elements, the substrate normal to the cholesteric helical axis of the liquid crystal in the liquid crystal domain in the pixel region near the substrate on the element observation side in the liquid crystal light modulation element in the selective reflection state on the element observation side. Is larger than the angle formed by the substrate normal of the cholesteric spiral axis of the liquid crystal in the liquid crystal domain in the pixel region near the substrate on the element observation side in the liquid crystal light modulation element in the selective reflection state on the side opposite to the element observation side. The multilayer liquid crystal light modulation device according to claim 26. 28. A cholesteric spiral axis of liquid crystal in a liquid crystal domain of a pixel region near a substrate on a side opposite to the element observation side of the liquid crystal light modulation element in a selective reflection state on the element observation side in each adjacent liquid crystal light modulation element. Angle of the cholesteric spiral axis of the liquid crystal in the liquid crystal domain of the pixel region near the substrate on the side opposite to the element observation side in the liquid crystal light modulation element in the selective reflection state on the side opposite to the element observation side. 28. The multilayer liquid crystal light modulation device according to claim 26, wherein the angle is larger than an angle formed with a substrate normal. 29. A laminated liquid crystal light modulation device comprising a plurality of liquid crystal layers each sandwiched between a pair of substrates, wherein at least one of the plurality of liquid crystal layers has:
Claim 7, together with a pair of substrates sandwiching the liquid crystal layer.
19. A stacked liquid crystal light modulation device constituting the liquid crystal light modulation device according to 8, 17, or 18. 30. In each of the adjacent liquid crystal light modulating elements, in the selective reflection state on the element observing side, the substrate normal to the cholesteric helical axis of the liquid crystal in the liquid crystal domain in the pixel region near the substrate on the element observing side in the liquid crystal light modulating element. Is larger than the angle formed by the substrate normal of the cholesteric spiral axis of the liquid crystal in the liquid crystal domain of the pixel region near the substrate on the element observation side in the liquid crystal light modulation element in the selective reflection state on the side opposite to the element observation side. A multilayer liquid crystal light modulation device according to claim 29. 31. A cholesteric spiral axis of a liquid crystal in a liquid crystal domain of a pixel region near a substrate on the side opposite to the element observation side in the liquid crystal light modulation element in the selective reflection state on the element observation side in each adjacent liquid crystal light modulation element. Angle of the cholesteric spiral axis of the liquid crystal in the liquid crystal domain of the pixel region near the substrate on the side opposite to the element observation side in the liquid crystal light modulation element in the selective reflection state on the side opposite to the element observation side. 31. The multi-layer liquid crystal light modulation device according to claim 29, wherein the angle is larger than an angle formed with a substrate normal. 32. In each adjacent liquid crystal light modulation element, the rubbing density of the rubbed alignment control layer in the liquid crystal light modulation element on the element observation side corresponds to the alignment control layer.
32. The multilayer liquid crystal light modulation device according to claim 30, wherein the rubbing density of the rubbed alignment control layer in the liquid crystal light modulation device on the side opposite to the device observation side is smaller than the rubbing density. 33. A method for manufacturing a liquid crystal light modulation element comprising a pair of substrates sandwiching a liquid crystal layer containing a liquid crystal material exhibiting a cholesteric phase at room temperature and having a selective reflection wavelength peak in a visible wavelength region. At least one of the pair of substrates so that the liquid crystal layer in the reflection state is in a mixed state of a poly domain and a mono domain in a liquid crystal domain in a pixel region near at least one of the substrates near the two substrates. A substrate processing step of processing one substrate; and a step of sandwiching the liquid crystal layer between the pair of substrates on which at least one substrate has been processed in the substrate processing step. Manufacturing method. 34. In the substrate processing step, of the liquid crystal domains in the pixel regions near the two substrates in the selective reflection state, the liquid crystal domains in the pixel region near the substrate on the side opposite to the element observation side are in the mixed state, 34. The method for manufacturing a liquid crystal light modulation element according to claim 33, wherein the pair of substrates is processed so that a liquid crystal domain in a pixel region near the substrate on the element observation side is composed of only a poly domain. 35. The substrate processing step, comprising: providing an alignment control layer on at least a side of the pair of substrates facing the liquid crystal domain of the mixed state liquid crystal domain; 34. A rubbing step of rubbing the orientation control layer provided on the facing substrate, wherein the rubbing step sets the rubbing density of the rubbed orientation control layer to 10 or less.
35. The method for producing a liquid crystal light modulation device according to 34. 36. A method for manufacturing a liquid crystal light modulation element comprising a liquid crystal layer sandwiched between a pair of substrates and including a liquid crystal material exhibiting a cholesteric phase at room temperature and having a selective reflection wavelength peak in a visible wavelength region. Each of the liquid crystal domains in the pixel region near the substrates facing the both substrates in the reflection state has a polydomain structure, and the cholesteric spiral axis of the liquid crystal is used between the liquid crystal domains in the pixel regions near the two substrates. A substrate processing step of processing the pair of substrates such that angles formed with the lines are different; and a step of sandwiching the liquid crystal layer between the pair of substrates processed in the substrate processing step. A method for manufacturing a liquid crystal light modulation element. 37. In the substrate processing step, of the liquid crystal domains in the pixel region near the two substrates in the selective reflection state, the substrate normal to the cholesteric spiral axis of the liquid crystal in the liquid crystal domain in the pixel region near the substrate on the element observation side. 37. The liquid crystal light modulation device according to claim 36, wherein the pair of substrates is processed so that an angle formed between the pair of substrates is larger than an angle formed by a substrate normal of a cholesteric helical axis of liquid crystal in a liquid crystal domain of a pixel region near an opposite substrate. Production method. 38. The substrate processing step includes providing an alignment control layer on each of the pair of substrates facing the liquid crystal layer; and aligning at least one of the alignment control layers provided on the two substrates. 38. The method of manufacturing a liquid crystal light modulation device according to claim 36, further comprising: rubbing a control layer, wherein the rubbing process sets the rubbing density of the alignment control layer to be rubbed to 10 or less.