KR101600501B1 - Liquid crystal device - Google Patents

Abstract

The present invention relates to a liquid crystal display device, in which a liquid crystal display device is provided with an electrode pattern (41; 42), which is a nonuniformity generated over a first sub- volume of a bulk layer (44) adjacent to the electrode pattern A ferroelectric and / or flexible dielectric coupling between the in-plane electric field and the liquid crystals in the polarization state included in the alignment layer 43 to which the first sub-volume and / or the electrode pattern 41 (42) , And wherein the polarization is selected from the group consisting of (i) the first sub-volume and / or the second alignment layer (43), and (ii) a second electrode Is stronger than any possible similar liquid crystal polarization of the bulk layer (44) outside the second sub-volume of the bulk layer adjacent the pattern or second alignment layer, or the inner surface of the other substrate.

Description

[0001] LIQUID CRYSTAL DEVICE [0002]

The present invention relates generally to the field of liquid crystals. More particularly, the present invention relates to a liquid crystal device driven by linear coupling, such as ferroelectric and / or flexoelectric coupling between an applied in-plane electric field and liquid crystals in a polarized state, ≪ / RTI >

Generally, nematic liquid crystal displays (LCDs) operate based on dielectric coupling, i.e., operate based on coupling between the dielectric anisotropy (?) Of the liquid crystal resulting in an electro-optical response and the applied electric field do. This response is quadratic with respect to the applied electric field, in other words not polarity, but from the switching of the liquid crystal molecules by the electric field. In conventional nematic LCDs, the switching of the liquid crystal molecules occurs in a plane that includes the direction of the applied electric field, which means that the applied electric field across the liquid crystal sandwich cell is out-of-plane, And will switch molecules in a plane perpendicular to the cell substrates. This type of switching results in an electro-optic response with a contrast ratio that strongly depends on the viewing angle. Also, the switching time, which is the sum of the total response time?, I.e., the sum of the rise time? _R and the fall time (electric field-off) time? _F , is usually not short enough for moving picture display.

On the other hand, LCDs having interdigitated electrode patterns disposed on the inner surface of one of the substrates (producing an in-plane electric field) exhibit in-plane switching (IPS) of the optical axis and thereby make the contrast ratio less dependent on viewing angle . A herringbone electrode structure is used in an improved version of super-in-plane switching (S-IPS). Nevertheless, the switching time of the liquid crystal devices operating the IPS-mode is not short enough to produce good quality moving images.

The in-plane electric fields can also be effectively generated by a comb-like electrode structure that produces a fringe electric field. However, even in such so-called fringe field switching (FFS) devices, dielectric coupling is generally used and therefore the problem caused by the above-mentioned long electric-off time is not solved.

In the above examples, it should be mentioned that, unlike the rise time? _R , the electric field-off time? _F does not depend on the magnitude of the applied electric field. Thus, the rise time can be effectively controlled by the electric field, but the electric field-off time is independent of the electric field. The electric field-off time depends only on the cell properties such as the cell gap and the parameters of the liquid crystal materials such as viscosity and alignment regulating strength to solid substrates.

Another known method of switching nematic liquid crystals between different optical states utilizes a linear coupling between the applied electric field and the flake propulsive bulk polarization of the initially modified nematic liquid crystal ("Flexoelectrically controlled twisted texture in a nematic liquid crystal ", Dozov et al., J de Phys Lett, 43 (1982), L-365 to L-369); "A novel polar electrooptic effect in reversely pretilted nematic liquid crystal layers with weak anchoring ", Komitov et al., Proceedings of 3rd International Display Research Conference, October 1983, Kobe, Japan).

WO 2005/071477 discloses a liquid crystal device comprising a flexible inherent liquid crystal bulk layer in which an inhomogeneous electric field is generated in a direction substantially parallel to the substrates by interdigitated electrode patterns on the substrates. It is desirable if the average polarization direction in the direction parallel to the substrates in the electric field-off state is orthogonal to the direction in which the electric field should be generated. In this case, the rise time and the fall time are electric field-dependent, thereby reducing the overall response time.

US 6 160 600 discloses a liquid crystal display having common electrodes and display electrodes disposed on one of two substrates. The orientation of the liquid crystal material is of the hybrid alignment nematic (HAN) type. In such an apparatus, the liquid crystal material near the substrate on which the electrodes are provided is switched by dielectric coupling to an electric field, thereby requiring a liquid crystal material having a high dielectric constant. This switching mode also does not allow directional control of the switching.

A ferroelectric liquid crystal (FLC) display device including a comb-like electrode is also known (JP 10-161128).

BACKGROUND OF THE INVENTION [0002] It has recently been realized to in-plane switch nematic liquid crystals by means of an electric field applied across cell substrates, using an electrically commanded surface (ECS). Published International Patent Application No. WO 00/03288 discloses the so-called Electrically Commanded Surfaces (ECS) principle.

According to the ECS principle, a separate thin chiral smectic liquid crystal layer, preferably ferroelectric (chiral smectic C), is deposited on the inner surface (s) of either or both of the substrates defining the liquid bulk material in a conventional sandwich cell Phase, SmC ^* ) liquid crystal polymer layer is disposed.

The chiral smectic liquid crystal polymer layer acts as a surface-to-orientation alignment layer that forces a planar or substantially planar orientation in adjacent liquid crystal bulk materials. More specifically, when applying an external electric field across the cell - and thus across the surface-direction alignment layer, molecules in a separate chiral smectic liquid crystal layer will be switched. The change in the dynamic surface-director alignment layer in response to an electric field is referred to as "primary surface switching." Primary surface switching results in molecular oriented switching within the bulk volume of the liquid crystal bulk material defined between the substrates in turn via elastic forces (steric coupling). This secondary switching is referred to as "induced bulk switching. &Quot; This derived bulk switching is in-plane switching. Thus, molecular switching in the dynamic surface-director alignment layer will be propagated through the elastic force into the bulk volume at the interface between the separate surface-director alignment layer and the bulk layer, resulting in relatively fast in-plane switching of the mediated bulk-volume molecules.

The chiral smectic liquid crystal layer, i. E. The dynamic surface-director alignment layer, is either synclinic or anticlinic chiral smectic on both sides, for example Smectic C (SmC ^* or SmC _A ^* ), a material or a chiral smectic A (SmA ^* ) material (this includes so-called random SmC ^* ). Thus, the response of the dynamic surface-director alignment layer to the applied electric field may be ferroelectric, antiferroelectric or paraelectric, respectively.

Published International Patent Application No. WO 2003/081326 discloses a liquid crystal device comprising a liquid crystal bulk layer and chiral dopants that are non-uniformly distributed in the bulk layer as a result of being permanently attached to one or more surfaces, Induces spontaneous polarization in the sub-volume of the bulk layer adjacent to the surface. The response of the bulk layer in the sub-volume to the applied electric field across the bulk layer may be ferroelectric, antiferroelectric, or paraelectric.

The use of ECS layer / sub-volume in a liquid crystal device provides relatively fast in-plane switching and high image contrast ratio. However, it is desirable to further improve the contrast ratio. Also, the voltages required are somewhat higher.

A general object of the present invention is to alleviate the above-mentioned problems and to provide an improved liquid crystal device. In particular, it is an object of the present invention to provide a liquid crystal device capable of producing a high contrast ratio and a wide viewing angle and exhibiting fast in-plane switching, and more particularly, To reduce the overall switching time.

Another object of the present invention is to reduce the magnitude of the threshold voltage adjusting the switching of the liquid crystal bulk, in other words, to reduce the driving voltage of the liquid crystal device. This is especially important in portable applications such as mobile phones.

The present invention is not only applicable to displays but also to many other liquid crystal devices.

According to a first aspect of the present invention, a liquid crystal device provided by the present invention comprises: a first and a second confining substrate; A liquid crystal bulk layer disposed between the substrates; A first electrode pattern applied on an inner surface of the first substrate; And a first alignment layer applied on the first electrode pattern and arranged to interact with the bulk layer at a bulk surface, wherein the first electrode pattern comprises a first electrode layer of the bulk layer adjacent the first alignment layer, 1 sub-volume, wherein the electric field is non-uniform with respect to the direction and intensity of the electric lines, and the electric field is also generated across the first alignment layer. The liquid crystal device according to any one of the preceding claims, wherein the liquid crystal device comprises liquid crystals in a polarized state included in the first sub-volume and / or the first alignment layer, wherein the polarization of the liquid crystals comprises (i) And (ii) a second sub-volume of the bulk layer adjacent to the second substrate and / or a second sub-volume of the bulk layer outside the second alignment layer arranged on the second substrate, Further comprising liquid crystals stronger than quasi liquid crystal polarization; The liquid crystals in the first sub-volume and / or in the polarization state contained in the first alignment layer are switched, at least in part, by coupling between the electric field and the polarization so that the switching of the liquid crystals of the bulk layer Is accomplished.

Other aspects, features, and advantages of the present invention will become apparent from the detailed description of the invention that follows.

1 is a schematic diagram showing interdigitated electrode patterns for execution in an apparatus according to the invention;

2 is a schematic cross-sectional view showing an in-plane electric field generated by interdigitated electrode patterns shown in FIG.

3 is a schematic cross-sectional view illustrating an electrode structure including a comb-like electrode for generating a fringe electric field in an apparatus according to the present invention.

Figures 4 to 14, 16 and 17 illustrate how flexible inherent polarization in one of the substrate surfaces is induced by the anchoring properties of the alignment layer and / or surface topography in the device according to the present invention, ≪ / RTI >

Figure 15 is a schematic cross-sectional view showing how flexion pristine polarization can be induced at the inner surface of each substrate by the alignment control characteristics of the alignment layers and / or the surface topography in an apparatus according to the present invention.

FIGS. 18 and 19 are schematic cross-sectional views illustrating how the flake inherent polarization can be induced by a wall dividing device spacing in a plurality of cells in an apparatus according to the present invention.

FIGS. 20-25 illustrate the performance and structure of an apparatus according to the present invention comprising a nematic bulk layer with hybrid alignment (HAN) and interdigitated electrodes.

Figures 26-31 illustrate the performance and structure of an apparatus according to the present invention including electrodes meshed with a nematic bulk layer with reversed hybrid alignment.

32 to 36 show the performance and structure of an apparatus according to the present invention including electrodes interdigitating with a ferroelectric alignment layer.

37-44 illustrate the performance and structure of an apparatus according to the present invention comprising a nematic bulk layer with an inverse hybrid alignment and an electrode pattern generating a fringe field.

FIGS. 45-50 and FIGS. 53-55 illustrate the performance and structure of an apparatus according to the present invention, including an electrode pattern to produce a ferroelectric alignment layer and a fringe field.

Figures 51 and 52 illustrate the performance and structure of an apparatus according to the present invention including an electrode pattern that produces an electric field across the ferroelectric alignment layer and the bulk.

56 to 58 and 60 show embodiments of top electrode structures used in an electrode pattern for generating a fringe electric field in an apparatus according to the present invention.

59 shows an embodiment of an apparatus comprising an electrode pattern for generating a nematic filled fringe field directed perpendicular to the substrates.

The present invention relates to a liquid crystal device,

First and second confining substrates, such as glass or plastic substrates; A liquid crystal bulk layer disposed between the substrates; A first electrode pattern applied on an inner surface of the first substrate; And a first alignment layer applied over the first electrode pattern and arranged to interact with the bulk layer at a bulk surface,

Wherein the first electrode pattern is arranged to produce a non-uniform electric field over a first sub-volume of the bulk layer adjacent the first alignment layer, the electric field being non-uniform with respect to the direction and intensity of the electric lines, Is also generated over the first alignment layer,

The liquid crystal device according to any one of the preceding claims, wherein the liquid crystal device comprises liquid crystals in a polarization state included in the first sub-volume and / or the first alignment layer, wherein the polarization of the liquid crystals is (i) And (ii) a second sub-volume of the bulk layer adjacent to the second substrate and / or a second sub-volume of the second sub-layer disposed outside the second alignment layer, Further comprising liquid crystals stronger than any possible similar liquid crystal polarization of the liquid crystal; The liquid crystals in the first sub-volume and / or in the polarization state contained in the first alignment layer are switched, at least in part, by coupling between the electric field and the polarization so that the switching of the liquid crystals of the bulk layer Is accomplished.

It should be noted that in the case where the liquid crystal device described above includes a (first) alignment layer applied on the (first) electrode pattern, the first sub-volume is adjacent to the (first) alignment layer.

It is preferred that there is polarization and / or alignment of the sub-volume in the absence of an electric field (i. E. In an electric field-free condition).

As used herein, the term " similar polarization "refers to the intensity of polarization in sub-volume and / or alignment layers and the intensity of polarization in the bulk layer that is outside of the first and second sub- When comparing the intensities of polarization, it refers to polarization that provides the same type of electrical coupling, i. E., Ferroelectric or flake-inherent coupling.

As used herein, the term "adjacent to" as in the sub-volume of liquid crystal bulk material adjacent to the substrate indicates that the sub-volume comprises a portion of the bulk material located closest to the substrate. This does not preclude the possibility that additional components of the device according to the invention, such as electrode patterns and alignment layers, are disposed between such sub-volume and the substrate.

The alignment layer is one of a passive alignment layer or an active alignment layer.

In the case where the liquid crystals in a polarized state are included in the alignment layer, they may be referred to as aligned laminar dynamic alignment layers, which will then be coupled with the applied electric field to effect the switching of the liquid crystals. The apparatus according to the present invention may additionally or alternatively comprise a passive alignment layer (s) applied on one or both of the substrate surfaces.

Since the electric field is generated by the electrode pattern comprising the electrodes applied on the same substrate surface, the electric field is substantially localized near the substrate surface with the electrode pattern bearing. Therefore, the electric field exponentially weakens in the liquid crystal bulk layer. In addition, the electric field includes electric field lines which are directions substantially parallel to the substrate surface, in other words, an in-plane electric field is generated.

The electric field is generated by an electrode pattern comprising one of fringe-electric field generating electrodes or interdigitated electrodes, preferably an electrode pattern comprising a comb-like electrode structure.

If the liquid crystal molecules in the polarization state contained in the first sub-volume and / or the (dynamic) alignment layer have a strong dielectric constant (DELTA epsilon), the switching may be in addition to coupling between the electric field and the polarization, (But need not) have a dielectric coupling component to it.

An electrode pattern comprising interdigitated electrodes 1 and 2 applied on the inner surface of one of the substrates 3 is shown in Fig. As shown in Fig. 2, the electric field E generated by the interdigitated electrodes 1 and 2 is substantially localized at the surface of the substrate bearing the electrodes 1 and 2. The electric field E mainly comprises electric field lines which are in a direction substantially parallel to the substrate surface 3 to which the electrodes 1 and 2 are applied. However, the electric field E also includes some non-parallel directions of the electric field lines, including those substantially perpendicular to the substrate surface 3 to which the electrodes 1 and 2 are applied. The direction of the electric lines change when one electrode gap passes the next electrode gap. Therefore, the electric field is non-uniform with respect to the direction (and intensity thereof) of the electric lines.

As will be appreciated by one of ordinary skill in the art, electrode patterns comprising interdigitated electrodes may have many other shapes besides the shape illustrated in FIG. A common feature of all electrode patterns, including interdigitated electrodes, is that the electrodes are disposed in the same geometric plane.

FIG. 3 shows an electrode pattern including a comb-like electrode structure. The electrode pattern is disposed on the substrate surface 5 and is disposed on the first conductive layer, for example, a first conductive layer 4 (also referred to as a common electrode or a bottom electrode) which is an indium tin oxide (ITO) And a second conductive layer 7 (also referred to as a top electrode) disposed on the top of the insulating layer and being an ITO layer, for example, and the second conductive layer 7 is a comb-like . Alignment layer 8 is also shown in Fig. The electric field (fringe field) produced by this electrode structure is substantially localized near the substrate surface 5 with the electrodes 4 and 7 interposed therebetween. The electric field E includes both the electric line Ez which is a direction substantially perpendicular to the electric line Ex which is a direction substantially parallel to the substrate surface 5 to which the electrodes 4 and 7 are applied (In other words, the fringe electric field includes an electric field component along the substrate surface 5 and an electric field component perpendicular to the substrate surface 5). The distribution of the front lines and their intensity depend on the geometry of the electrodes 4 and 7 and their mutual position.

Another type of electrode pattern that creates a fringe field is a first conductive layer (a bottom electrode) disposed on a substrate surface, an insulating layer disposed on the first conductive layer, and an insulating layer disposed on the insulating layer and having openings And a second conductive layer (a top electrode). The second conductive layer may have a structure as shown in FIG. 56 or a similar structure. 56A shows a top electrode structure having hexagonal openings. Figure 56b shows a top electrode structure with openings in the form of circular spots and Figure 56c shows a top electrode structure with square openings. As can be appreciated by one of ordinary skill in the art, the top electrode may take many forms other than those shown in FIG. This type of electrode pattern is advantageous for displaying wide viewing angle images. The electric field obtained by the electrode pattern according to any of the embodiments shown in Fig. 56 will have a plurality of symmetry axes extending along the vertical line to the substrate surface and extending through the center of the aperture. Because of the local symmetry of the electric field, and thus due to the local symmetry of the liquid crystal alignment, the device with such an electrode pattern will have an orientation independent of the viewing angle and an excellent viewing angle.

57 and 58 show the orientation of the liquid crystal bulk molecules 62 on one substrate surface 63 of the liquid crystal display device in the electric field-off and electric field-on states, respectively, wherein the liquid crystal display has a vertical orientation A nematic liquid crystal bulk layer 62 exhibiting a positive dielectric anisotropy and a fringe-to-disturbance generating electrode pattern, the fringe field generating electrode pattern comprising an alignment layer (not shown) And a top electrode 66 having an insulating layer 65 disposed on the bottom electrode and openings in the form of circular spots.

The device structure in Figs. 57 and 58 can also be applied to the case of having a nematic liquid crystal bulk layer exhibiting negative dielectric anisotropy.

59A shows a side view of an apparatus using the comb-like electrode structure of FIG. 38, wherein liquid crystal bulk molecules are vertically oriented.

FIG. 59B shows a side view of the electrode structure in FIGS. 38 and 58 and also shows a non-uniform electric field distribution of the electric lines in the electric-on state. FIG.

59A shows an apparatus including an electrode structure formed on the inner surface of the substrate 63. Fig. The molecules of the liquid crystal bulk layer are oriented perpendicular to the substrate surface by alignment layers 70 and 68 disposed on the substrates 63 and 69. The electrode structure produces a non-uniform electric field (fringe electric field) (Figure 59b). If the liquid crystal material has a positive dielectric anisotropy (Δε> 0), when the electric field is applied to the cell, the molecules of the liquid crystal bulk will tend to follow the electric field lines. However, this will result in periodic splay-bend elastic deformations in the sub-volume near the electrode pattern, and if the liquid crystal bulk material has flexoelectrical polarizability, Owing to inherent polarization. If the applied electric field has the proper shape and polarity, coupling of the electric field and the flake inherent polarization can reduce the switching time of the cell.

The device shown in Fig. 59A can also be applied to the case of having a nematic liquid crystal bulk layer having negative dielectric anisotropy (DELTA epsilon < 0).

Figure 60 shows the orientation of liquid crystal bulk molecules in a double sided device in an electric-on state.

It should be noted that the apparatus according to the present invention can be applied to either a cross-sectional device or a double-side device.

In an embodiment of the cross-sectional device of the device according to the invention, only one of the substrates comprises an electrode pattern applied on its inner surface.

In an embodiment of the double-sided device of the device according to the invention, both substrates include an electrode pattern applied on each inner side. Therefore, in such an apparatus, it is desirable to provide a method of forming an electrode pattern on an inner surface of another substrate so as to generate a non-uniform electric field over a second sub-volume of the bulk layer adjacent to the second electrode layer, A second electrode pattern is applied where the electric field is non-uniform with respect to the direction and intensity of the electric lines.

In an apparatus (embodiment of the double-side apparatus) according to the present invention comprising electrodes of the same type intermeshed applied on two substrates, the orientation along the first substrate surface of the electrodes applied on the first substrate is oriented on the second substrate Is angled relative to the orientation of the electrodes applied to the second substrate surface. This type of device significantly increases the viewing angle of the display device.

In an apparatus according to the invention comprising interdigitated electrodes of the type shown in Figure 1 applied on two substrates, the first and second substrates are arranged in a direction substantially perpendicular to the direction of the electrodes arranged along the second substrate surface, It is particularly preferred that the electrodes on the first substrate are arranged along the surface of the substrate.

Further, in an embodiment of the double-sided device of the device according to the invention, each sub-volume (first and second sub-volumes, respectively) adjacent each of the electrode patterns or the alignment layers applied on the electric patterns, It is preferred to include liquid crystals exhibiting an applied electric field and ferroelectric or flake-inherent coupling in this polarization state. In this case, the polarization in each of the sub-volume (s) and / or the alignment layer (s) can be controlled by any possible liquid crystal polarization of the bulk layer outside the sub-volume (s) and / It is stronger than. It should be noted, however, that the polarization intensities in each sub-volume and / or in the alignment layer may be different compared to each other.

More specifically, the liquid crystals in the sub-volume and / or in the polarization state contained in the alignment layer represent one of the induced polarization, including spontaneous polarization or induced spontaneous polarization.

In particular, the coupling between the sub-volume and / or the polarization in the alignment layer and the applied electric field is one of ferroelectricity, antiferroelectricity, paraelectric or flake inheritance.

In the first group of embodiments of the present invention, the alignment layer comprises a chiral smectic (Sm ^* ) liquid crystal material such as SmC ^* , SmC _A ^* , or SmA ^* .

The smectic liquid crystal structure includes liquid crystal molecules disposed in adjacent smectic layers. Smectic A and smectic C phases are the two most important representations of these "layered" liquid crystals. Further, the smectic liquid crystal molecules can be achiral (e.g., SmA, SmC or SmCA) or chiral (e.g., SmC ^* , SmC _A ^* , or SmA ^* ), Means a deficiency of mirror symmetry.

A tilted chiral smectic liquid crystal has a director that rotates in a cone from one smectic layer to the next. The apex angle θ = 2β of the cone can typically be about 45 °. Thereby, a helix texture is formed across the layers, with the helical axis parallel to the axis of the cone and perpendicular to the smectic layers. However, the local spontaneous polarization (Ps) coupled to the director will then also rotate in a spiral form with the same period or pitch. This spiral structure of local polarization means that local polarization means self-cancellation, in other words, bulk liquid crystal will not exhibit any macroscopic polarization.

In the smectic A phase structure, the average direction of the molecules is parallel to the smectic layer normal (β = 0 °), that is, the molecules are oriented along the smectic layer normal. If the electric field is applied to a chiral smectic A (SmA ^* ) liquid crystal structure, the response to the applied electric field will be a so-called phase dielectric response.

In the smectic C phase structure, the molecules are tilted at an angle β (typically about 22.5 °) with respect to the smectic layer normal.

In a synclinic smectic, for example, a smectic C liquid crystal structure, the molecules of two adjacent smectic layers are tilted in the same direction with respect to the smectic layer normals. If the electric field is applied to a chiral smectic, eg, smectic C ^* (SmC ^* ) liquid crystal structure that is tilted at both sides, the response to the applied electric field will be a so-called ferroelectric response.

Tilted smectic (anticlinic smectic) to the opposite side each other, for example, smectic C _A, in the liquid crystal structure, the molecules of two adjacent smectic layers are tilted in the opposite direction with respect to the smectic layer normal. A chiral smectic in which the electric field is inclined to the opposite side, for example, smectic C _A (SmC _A ^* ) liquid crystal structure, a so-called anti-ferroelectric response will occur. By the way, if the applied electric field exceeds a certain threshold, the structures inclined opposite to each other will be deformed into a mutually inclined structure, in other words, a ferroelectric response to the applied electric field will be provided.

Thus, in embodiments of this first group of devices according to the present invention, the coupling between the polarization and the applied electric field in the alignment layer may be ferroelectric, antiferroelectric or paraelectric, more preferably ferroelectric have. As explained in the introduction, molecular directed directed switching of liquid crystals in the bulk layer through elastic force (steric coupling) by primary switching of molecules in such a chiral smectic alignment layer Results.

In embodiments of this group of devices according to the present invention, the chiral smectic alignment layer is a chiral smectic, for example, smectic C (SmC ^* ), liquid crystal material, Photochromatic C (SmC ^* ) liquid crystal polymer (also referred to as ferroelectric liquid crystal polymer (FLCP)).

The chiral smectic liquid crystal material such as FLCP of the alignment layer is preferably insoluble in the liquid crystal material of the bulk layer. In particular, the liquid crystal material of the alignment layer should not affect the properties of the liquid crystal material of the bulk layer or vice versa.

0을 가지는 네마틱 또는 스메틱 액정 물질을 포함하는 것이 바람직하다. 따라서, 액정 물질은 인가된 전기장과 실질적으로 어떤 유전성 커플링도 나타내지 아니한다.In this first group of embodiments, the bulk layer is a chiral or non-chiral nematic or smectic liquid crystal material, more preferably zero or very small positive or negative dielectric anisotropy,

0 &lt; / RTI &gt; Thus, the liquid crystal material does not exhibit substantially any dielectric coupling with the applied electric field.

In the case where the bulk layer comprises a bicaralamic liquid crystal material, it may be appropriate that the smectic layers of the bulk layer are substantially parallel to the smectic layers of the alignment layer.

Furthermore, it is desirable that the smectic layers of the alignment layer be oriented substantially parallel to the applied electric field.

In this first group of embodiments according to the present invention, the alignment layer described above may also be referred to as a dynamic alignment layer, because it is affected by the applied electric field and is coupled to the electric field.

An apparatus according to this first group of embodiments of the present invention may also include a passive alignment layer under the dynamic alignment layer so that the passive alignment layer may provide an alignment direction preferred for the dynamic alignment layer have.

In an apparatus according to the present invention having an alignment layer comprising chiral smectic liquid crystal molecules such as FLCP, as described in Examples 3 and 4, the flake inherent bulk bulk polarization is induced.

Further, in embodiments of this group, the liquid crystal bulk molecules adjacent to the substrate surface that sandwich the electrode pattern with the alignment layer applied thereon exhibit a higher molecular pretilt than the liquid crystal bulk molecules adjacent the opposing substrate surface .

Reference may be made to WO 00/03288 for further information on how to provide the aforementioned alignment layer exhibiting spontaneous polarization.

Embodiments of the second group of the present invention include a method of permanently attaching to one or more surfaces in the first sub-volume, thereby inducing a local increase in one or more chirality-related properties within the first sub- (Also referred to herein as the effect (s) of chirality), the chiral dopants are non-uniformly distributed in the bulk layer and are non-uniformly distributed at a maximum at the surface and decreasing in a direction away from the surface , Wherein the chiral dopants are soluble in the liquid crystal bulk layer.

The term "soluble" as used herein means that the dopants can be dissolved in the liquid crystal bulk layer.

The induced increase of the effect of chirality does not occur in the entire volume of the bulk layer but only in its limited region (sub-region) adjacent to the surface.

0을 가지는 SmC와 같은 비카이랄 스메틱 액정 물질을 포함한다.In the second group of embodiments, the bulk layer is a non-curable or chiral nematic or smectic liquid crystal material, preferably a non-cical smectic liquid crystal material such as SmC, more preferably a zero or very small positive or negative The dielectric anisotropy, i.e.,

0, &lt; / RTI &gt; such as SmC.

As an illustrative example of embodiments of this group, the bulk layer may comprise a bicaralamic C liquid crystal material. In the sub-region, the bicarylsymatic C is doped by chiral dopants that are soluble in the noncaramic C and are permanently attached to the surface in the sub-volume. The dopants induce chirality in the sub-bulk liquid crystal bulk material and thereby induce an increase in chirality effect (s). The induced chirality results in sub-volumetric spontaneous polarization which, in turn, provides ferroelectric properties. The actual volume of the doped sub-region and the sub-volume representing the chirality and spontaneous polarization may be somewhat different, since the dopant molecules will also induce chirality at a certain distance from the dopants. By applying the electric field over the sub-volume representing the induced spontaneous polarization, molecules will switch very quickly by direct ferroelectric coupling to the applied electric field. This fast ferroelectric switching in turn results in fast switching of bulk molecules outside the sub-volume, due to the elastic coupling between molecules in the bulk volume and adjacent molecules in the surface sub-region.

The chiral dopants are permanently attached to the surface, which should be interpreted as the bond of the dopants to the surface in such a way as to prevent free escape from the bulk volume. Although the dopants are permanently attached to the surface, they may still have limited mobility, particularly mobility, which allows the dopant molecules to be redirected from the surface, for example during switching by an applied external electric field.

The surface to which the dopants are to be attached must be held to include the surface located at the boundary of the bulk layer or the surface defining the boundary as well as the sub-volume interior. Thus, in this regard, the term "surface" may include any physical or geometric surface or plane that is in direct or indirect contact with the bulk layer material in the sub-volume through the dopant material.

Preferably, the dopants are attached to the inner surface of the alignment layer or the electrode pattern arranged to interact with the liquid crystals of the bulk layer and thereby provide a pre-emptive molecular orientation of the liquid crystals of the bulk layer.

In this second group of embodiments of the device according to the invention, the coupling between the applied electric field and the polarization in the first sub-volume can be achieved by means of ferroelectric, semi-ferroelectric Or may be paraelectric, more preferably ferroelectric.

See WO 2003/081326 for further information on how to provide the sub-volumes described above that represent induced spontaneous polarization.

In embodiments of the third group of devices according to the invention, the polarization of the liquid crystals of the first sub-volume is induced by splay and / or bend deformations of the liquid crystals in sub-volume, And between the liquid crystals in the polarization state in the first sub-volume.

및

는 각각 스플레이 탄성 변형 및 벤드 탄성 변형이다. 일반적으로 탄성 변형이 커질수록 P_flexo가 더 커진다. 비록 플렉소유전성이 액정들의 공통적인 물성일지라도, 다른 부호(sign)를 가지는 P_flexo를 나타내는 액정들 및 0의 P_flexo를 가지는 액정들이 존재한다.The flake inherent effect in liquid crystals is similar to the piezoelectric effect in solid materials, but is essentially entirely different. Flake inherent integrity refers to the polarization of liquid crystal material as a result of elastic deformation such as bend and / or splay deformations. It is stated in liquid crystal materials consisting of molecules having "shape polarity" in addition to permanent net dipole moments. The entire flex-proprietary polarization (P _flexo ) is given as P _flexo = e _s S + e _b B, where e _s is the splay-flip inherent modulus and e _b is the bend-flex inherent modulus. These are very important parameters that define the intensity of the flake inherent polarization.

And

Are splay elastic deformation and bend elastic deformation, respectively. Generally, the larger the elastic deformation, the larger the P _flexo . Even though the conductive Plectranthus own common physical properties of the liquid crystal, there are a liquid crystal having a liquid crystal and P 0 of the _flexo indicating P _flexo has a different sign (sign).

As is known to those of ordinary skill in the art, liquid crystal materials with splay and / or bend strains can induce polarization that provides the flexibility inherent to the applied electric field ).

Preferably in this third group of embodiments of the device according to the invention a liquid crystal material having a high flex-inherent polarized polarity, i. E. A liquid crystal material exhibiting high flex-polarized polarizations under elastic deformation, is used. Typically, such liquid crystal materials have a high value of at least one of the flex-inherent conductivity coefficients e _s and e _b . It should be noted that there are liquid crystal materials which do not exhibit any flake inherent polarization under elastic deformation, and thus liquid crystal materials for use in this third embodiment of the device according to the invention can not be arbitrarily selected.

Generally, there are splay deformations, bend deformations and asymmetrical hybrid (splay + bend) deformations.

In order to achieve the desired effects according to the present invention, it is preferred that the Fleck-in-Charge effect in the first sub-volume is such that the effect of the bulk dielectric outside the sub-volumes (the first sub-volume and the second sub- It is important that it is stronger than any possible flake propensity effect.

For example, an alignment layer having projections extending into a sub-volume and / or having variable alignment control characteristics that affect, for example, alignment direction, may be applied on one or both of the substrate surfaces, This can be accomplished by providing local splay deformations and / or bend deformations to the volume. The surface topography resulting from the protrusions may result in flex-owing polarizations of adjacent liquid crystals, either alone or in combination with the variable alignment control characteristics.

In this embodiment of the cross-sectional device, an additional (second) alignment layer, preferably representing a particular alignment direction, such as planar or vertical (homeotropic), is applied on the inner surface of another substrate.

Generally, the limited solid substrate surfaces are suitably surface treated, such as by applying a so-called (surface-directing) alignment layer (also referred to as a directing layer) on the limited substrate surfaces facing the liquid crystal bulk, The desired initial alignment of the liquid crystal layer is obtained. Initial liquid crystal alignments are defined by solid surface / liquid crystal interactions. The orientation of the liquid crystal molecules adjacent to the confinement substrate is transmitted to the liquid crystal molecules in the bulk through the elastic force, thereby forcing substantially the same orientation in all the liquid crystal bulk molecules. The director of liquid crystal molecules near the confinement substrate surfaces is constrained to point in a particular direction, such as perpendicular (also referred to as homeotropic or vertical) or parallel (also referred to as planar) to the confinement substrate surfaces. In some instances, it may be desirable for liquid crystal bulk molecules to be more oriented with a directional angle (pre-tilt angle) that is specifically tilted relative to the substrate.

In this third group of embodiments of the device according to the invention, the first sub-volume is permanently attached to at least one surface in the first sub-volume, thereby facilitating a local increase of one or more properties within the first sub- Resulting in the appearance of a flake inherent polarization that has a non-uniform distribution that is non-uniformly distributed in the bulk layer and promotes the flake inherent polarization in the bulk layer, decreasing in a direction that is maximum at the surface and away from the surface , The dopants are soluble in the liquid crystal bulk layer.

The dopants that can be used to promote flake inherent polarization in the sub-volume are, for example, dopants selected from the group consisting of banana-type, drop-type, drop-banana hybrid-type dopants and any combination of two or more thereof , Which have the desired effect due to their anisotropic form. Such dopants are known in the art to which they impart a greater flake inherent coefficient. The dopants may be mesogenic compounds, but are not limited thereto.

An embodiment of a method of setting the vertical alignment includes coating the limited substrate surfaces with a surfactant such as lecithin or hexadecyltri methyl ammonium bromide. The coated substrate surfaces are then preferably rubbed in a predetermined direction so that the electric field-induced planar orientation of the liquid crystal molecules will be oriented in a predetermined rubbing direction.

An embodiment of a method of setting the plane orientation is a so-called organic film rubbing method, wherein an organic coating of, for example, polyimide is applied on the substrate surface. The organic coating is then rubbed in a predetermined direction with the cloth, so that the liquid crystal molecules in contact with the layer will be oriented in the rubbing direction.

Figs. 4 to 19 show the alignment regulating characteristics (including the alignment direction) and / or the surface topography of the alignment layer in the sub-volume adjacent to the substrate surface that sandwich the electrode pattern (not shown in the figures) Lt; RTI ID = 0.0 &gt; polarized &lt; / RTI &gt; polarity can be induced. The direction of the plastic inherent polarization is indicated by the arrows in the drawings, and the dotted lines indicate the alignment direction of the liquid crystal molecules.

FIGS. 4 through 17 illustrate flexural inherent polarization induced by alignment layers showing different types of orientation directions and pyramidal or rectangular surfaces, such as vertical and planar orientations. D Flanders, D Shaver, and H Smith, Appl Phys Lett, 55, 2506 (1978); J Cheng, and G Boyd, Appl Phys Lett, 35, 444 (1979); G P Bryan-Brown, C V Brown, I C Sage, and V C HuI, Nature, V 392, 365 (1998); And C Brown, M Towler, V Hui, and G Bryan-Brown, Liquid Crystals, 27, 233 (2000) disclose methods for providing this type of periodic surface topography.

Figures 4, 7 and 8 each show an alignment layer with vertical and pyramidal features (applied over the pyramidal projections). In Fig. 4, the substrate surface between the pyramidal protrusions also exhibits a vertical orientation. The opposing substrate surface includes an additional alignment layer that exhibits planar alignment.

Figure 5 shows an alignment layer having a planar orientation between the pyramidal projections and a pyramidal profile having a vertical orientation (applied on the pyramidal projections). The opposing substrate surface includes an additional alignment layer that exhibits planar alignment.

Figures 6, 13 and 14 each show an alignment layer with planar and pyramidal features (applied over pyramidal protrusions). In Fig. 6, the substrate surface between the pyramidal protrusions also exhibits planar orientation. The opposing substrate surface includes an additional alignment layer that exhibits planar alignment.

Figure 9 shows an alignment layer with planar and pyramidal features (applied over pyramidal protrusions). The facing substrate surface includes an additional alignment layer that exhibits vertical alignment.

Figure 10 shows an alignment layer with planar and pyramidal features (applied over asymmetric pyramidal protrusions). The facing substrate surface includes an additional alignment layer that exhibits vertical alignment.

Figure 11 shows an alignment layer having a vertical orientation between pyramidal protrusions and a pyramidal topography with a planar orientation (applied on pyramidal protrusions). The facing substrate surface includes an additional alignment layer that exhibits vertical alignment.

Figure 12 shows an alignment layer with a pyramidal topography with vertical alignment and alternating planar alignment (applied over pyramidal protrusions). The opposing substrate surface includes an additional alignment layer that exhibits planar alignment.

Fig. 15 is an embodiment of a double-sided device according to an embodiment of the cross-sectional device shown in Fig. 4, wherein the flake inherent polarization is localized on the inner surface of each of the substrates.

Figure 16 shows an alignment layer having a rectangular topography with vertical and alternating planar orientations (applied over the rectangular projections).

Figure 17 shows an alignment layer having a rectangular topography with a planar orientation (applied over the rectangular projections).

Figures 18 and 19 are schematic cross-sectional views of devices according to the present invention in which the polymer-bearing dielectric polarization is generated by the polymer walls dividing the device gap in a plurality of cells. R Caputo, L De Sio, A V Sukhov, A Veltri and C Umeton, Opt Lett 29, 1261 (2004); And G Bartolino, Phys Rev Lett, 94, 063903 (2005), disclose methods of providing such types of polymer walls .

Alternatively, splay and / or bend deformations may be provided to the entire bulk (i.e., bulk polarization) in an apparatus according to the present invention.

Thus, the device according to the invention comprises a bulk layer with an asymmetric splay-bend hybrid variant, wherein

), (바람직하게는, 이러한 예에서 제1 서브-체적의 액정들은 음의 유전 이방성(Δε

0)을 나타내고 상기 제1 서브-체적은 실질적으로 벤드 변형을 나타내는 액정들을 포함한다), 또는The liquid crystals of the first sub-volume exhibit a substantially bend strain, and the bend flake inherent modulus (e _b ) is the predominant flex-specific inherent modulus of the flake inherent shear polarity (that is,

), (Preferably, in this example, the liquid crystals of the first sub-volume have negative dielectric anisotropy

0) and the first sub-volume comprises liquid crystals exhibiting substantially bend strain), or

), (바람직하게는, 이러한 예에서 벌크 층의 액정들은 양의 유전 이방성(

)을 나타내고 상기 제1 서브-체적은 실질적으로 스플레이 변형을 나타내는 액정들을 포함한다).The liquid crystals of the first sub-volume exhibit substantially a splay deformation, and the splay-flake inherent modulus (e _s ) becomes the dominant flake-inherent modulus of flake inherent polarizability (that is,

(Preferably, in this example the liquid crystals of the bulk layer have a positive dielectric anisotropy

) And the first sub-volume comprises liquid crystals exhibiting substantially a splay strain.

In these examples, the flake inherent effect in the first sub-volume is stronger than the flake inherent effect of the bulk layer outside the first sub-volume.

)을 나타낸다). 이러한 경우에서, 본 발명에 따른 전극 패턴들은 두 기판 표면들 상에 적절하게 적용되어서, 상기 전극 패턴에 인접한 벌크 층의 각각의 강하게 분극된 서브-체적에 걸쳐서 불균일한 전기장을 제공한다.In embodiments of this third group of devices according to the invention, it is also possible to use a bulk layer with a splay strain, wherein the splay-flake inherent modulus (e _s ) is the sum of the main flake inherent properties (And typically, the liquid crystals in the bulk layer have a positive dielectric anisotropy

). In such a case, the electrode patterns according to the present invention are suitably applied on the two substrate surfaces to provide a non-uniform electric field over each strongly polarized sub-volume of the bulk layer adjacent to the electrode pattern.

)을 나타낸다). 또한 이러한 경우에서, 전극 패턴들은 두 기판 표면들 상에 적절하게 적용된다.Similarly, in this third group of embodiments of the device according to the invention, it is possible to use a bulk layer with alternatively a bend strain, wherein the bend flake inherent modulus (e _b ) (And typically, the liquid crystals in the bulk layer have a negative dielectric anisotropy (&lt; RTI ID = 0.0 &gt;

). Also in this case, the electrode patterns are suitably applied on the two substrate surfaces.

If the device according to the invention as described above comprises a bulk layer with a symmetrical splay or bend strain and an electrode pattern applied only on one substrate surface (in the embodiment of the cross-sectional device), then the first sub- The flake inherent polarization has the intensity of the flake inherent polarization in the second sub-volume adjacent to the surface of the substrate lacking the electrode pattern (but with the alignment layer applied thereon).

In these third group of embodiments, it is preferred that the bulk layer comprises a nematic (chiral or non-curable) liquid crystal material. Further, when deformed by the elastic deformation, it is appropriate that the liquid crystal material of the bulk layer exhibits a pronounced flexural strength. Thus, preferably the liquid crystal material of the bulk layer exhibits flake inherent polarizability.

It should be noted that the intensity of the flake inherent polarizations depends on the magnitude and the sign of the flexural modulus and the degree of elastic deformation. For example, when the cell gap is reduced in the liquid crystal device, the flake inherent polarization increases.

Further, in this third group of embodiments, the average direction of the flake inherent polarization in the electric-off state in the first sub-volume is parallel to or 90 degrees relative to the substrate having the electrode pattern applied thereon Plane, and preferably substantially perpendicular to the directions in which the in-plane electric field is to be generated, in-plane switching of the liquid crystals in the bulk layer is achieved.

In addition, the present invention relates to a method of providing a liquid crystal display device according to the present invention as described above. The method comprising:

Applying an electrode pattern on the inner surface of the substrate, the electrode pattern being capable of producing a non-uniform electric field over a first sub-volume of the liquid crystal bulk layer adjacent to the electrode pattern, and,

Disposing an alignment layer on the electrode pattern, the electric field being generated over the alignment layer,

Forming a cell gap between the substrate and the second substrate having the electrode pattern and the alignment layer applied on the top,

Filling the cell gap with a liquid crystal material forming a liquid crystal bulk layer,

Providing liquid crystals in a polarized state to the alignment layer and / or the first sub-volume, wherein the polarization is applied to the bulk layer adjacent the inner surface of the first sub-volume, the alignment layer, and / Is stronger than any possible similar liquid crystal polarization of the bulk layer, either outside of the second sub-volume of the second sub-volume,

The polarization may be coupled with the electric field to effect the switching of the liquid crystals so that the switching of the liquid crystals of the bulk layer may be accomplished by an elastic force.

SUMMARY OF THE INVENTION Briefly, the present invention relates to a method of manufacturing a semiconductor device, comprising the steps of: providing an uneven in-plane electric field generated by the electrode pattern over a first sub-volume of a bulk layer adjacent to the electrode pattern and an alignment layer applied on the electrode pattern and / Such as ferroelectricity and / or FLEX-proprietary coupling between the liquid crystals in the polarized state contained in the liquid crystal device, wherein the liquid crystal device is at least partially driven by linear coupling,

The method of claim 1 wherein the polarization is selected from the group consisting of (i) a first sub-volume, a second sub-volume of a bulk layer outside the first alignment layer, and (ii) a bulk layer adjacent an inner surface of the another substrate, Is stronger than any possible similar liquid crystal polarization of the bulk layer, outside the applied optical second electrode or the second alignment layer.

From the above description of the liquid crystal device according to the present invention, other desirable features of the above-described method will be understood.

The present invention will be described in detail below with reference to the following non-limiting examples.

Example 1:

Hybrid alignment with interdigitated electrodes ( HAN ) &Lt; / RTI &gt;

A sandwich cell (Fig. 20) comprising two parallel glass substrates 9 and 10 forming a cell gap of about 20 mu m is used. An electrode pattern 11 (shown in Fig. 1) meshing with each other is provided on the inner surface of one of the substrates 9 (in the cross-sectional device). The spacing between two adjacent electrodes is about 20 microns.

A first alignment layer 12 made of Nissan SE-2170 rubbed parallel to the electrode pattern 11 to promote uniform planar alignment of the liquid crystal bulk layer, including liquid crystal molecules 13 provided in the cell gap, Is disposed on the electrode pattern (11).

A second alignment layer 14 made of NISSAN SE-1211 promoting vertical alignment is disposed on the inner surface of the other substrate 10.

The cell gap filled with the nematic liquid crystal material MLC 16000-000 (provided by Merck) has a positive dielectric anisotropy (??> 0).

Due to the orientations of the alignment layers 12 and 14, the nematic bulk 13 employs a hybrid alignment (HAN), i.e. alignment in the substrate 9 that sandwiches the electrode pattern 11 is planar, 10), the alignment is vertical (Figs. 20 and 21). The elastic deformation of this nematic bulk layer 13 results in a flex-inherent polarization (P _flexo ). In Figs. 21 to 23, both arrows indicate the direction of the sample optical axis.

Since the splay distortion is localized in the substrate 9 on which the electrode pattern 11 is sandwiched, and since MLC 16000-000 exhibits positive dielectric anisotropy, the strongest flexible inherent polarization here is localized, Splay distortion is predominant in the substrate 9 on which the substrate 11 is placed (Fig. 20).

Elastic strain and flex-inherent polarizations are placed in the same plane parallel to the electrode pattern 11 and perpendicular to the cell substrates 9 and 10. The flake inherent polarization is linearly coupled to the applied electric field E to provide rapid switching of the liquid crystals 13. The total measured switching time (τ _rise + τ _fall ) is about 8 to 12 ms when the applied voltage is 25V. In the conventional IPS liquid crystal device, the total switching time is about 28 to 34 ms under the same conditions.

22 and 23 schematically show the switching of the nematic liquid crystals 13 in one electrode gap. As shown in these two figures, the direction of switching depends on the polarity of the electric field E. As shown in FIGS. 24 and 25, respectively, in the two adjacent electrode gaps, the nematic LC molecules 13 switch clockwise and counterclockwise, respectively. These figures show the two states of the cell corresponding to different electric field polarities of the applied electric field (E). lt; RTI ID = 0.0 &gt; polarized &lt; / RTI &gt; Different colors correspond to different positions of the director (n) (shown as arrows in Figs. 24 and 25) relative to the optical axis of the lambda-red optical plate.

Example 2:

Hybrid alignment with interdigitated electrodes ( HAN ) &Lt; / RTI &gt;

The same type of sandwich cell is used in this embodiment as in Example 1, but the HAN texture is reversed (Figure 26). 26 and 27, the alignment induced by the first alignment layer 18 on the substrate 15 having the electrode pattern 17 is vertical and the second alignment on the opposite substrate 16 The alignment induced by layer 20 is planar.

Cells are also filled with another nematic liquid crystal material (19) MDA-05-187 (provided by Merck) with a negative dielectric anisotropy (Δε <0).

Since the bend strain is localized on the substrate 15 having the electrode pattern 17 and since MDA-05-187 exhibits a negative dielectric anisotropy, the strongest flexible inherent polarization (P _flexo ) here is localized In other words, the bend deformation is dominant in the substrate 15 holding the electrode pattern 17 (Fig. 26). 27 to 29, both arrows indicate the direction of the sample optical axis.

The switching of the nematic, including the switching time, was found to be similar to the switching described in Example 1, and is schematically shown in Figures 28 and 29. By contrast, in contrast to the switching described in embodiment 1, where the _{flip-flops integral} P _flexo and the _{fl exible} coupling have the same direction, in these embodiments these couplings have opposite directions. In a weak or medium electric field, the flex-dominated coupling (P _flexo ) will be dominant over the dielectric coupling of the electric field (E) and the dielectric anisotropy. However, dielectric coupling dominates at strong electric and high frequencies. Thus, by first applying the dc voltage to the electrodes, the nematic molecules 19 (in a clockwise and counterclockwise direction, respectively) due to the flake inherent coupling, depending on the polarity of the electric field E applied at the corresponding electrode gap Is switched. Due to the inherent coupling, a strong high frequency pulse switches the nematic 19 back to its original state. As a result, application of the dc voltage causes the nematic 19 to be switched on (Figs. 30a, 30b and 30c), while the high frequency pulses cause the nematic 19 to move in the pre- 30 and 31), which is parallel to the electrodes 17, as in the first embodiment (Figs. 31A and 31B).

Example 3

The electrodes Chiral Smyth The alignment layer  Cells Containing

The cell used in this embodiment (Fig. 32) has the same structure as that used in the first embodiment. By the way, in this embodiment, the two inner surfaces of the substrates 21 and 22 are pre-tilt (θ _a) a quasi-along a plane (quasi-planar) electrodes so as to facilitate the alignment (23) rubbed in a single direction (Not shown) containing Nissan SE-2170.

A thin film ferroelectric liquid crystal polymer (FLCP), more specifically a ferroelectric side-chain polysiloxane (not shown), is disposed on top of the alignment layer covering the electrode pattern 23. The FLCP layer is aligned with the bookcase shape, that is, the smectic layers parallel to the substrate surface 21, with the molecular tilt ([theta] _b ).

The cell gap is filled with a nematic liquid crystal material 24 prepared in-house that has negative dielectric anisotropy (DELTA epsilon < 0) and is not mixable (dissolving) in the FLCP.

The applied electric field E in this embodiment does not directly switch the nematic molecules 24 due to negative dielectric anisotropy. However, the electric field E switches the molecules of the FLCP by spontaneous polarization of the FLCP material, which in turn switches the nematic liquid crystal molecules 24 of the bulk layer by elastic force (see WO 00/03288). Thus, the electric field polarity E is changed to switch the pre-aligned alignment direction of the nematic bulk 24 within the plane of the substrates 21 and 22 (i. E., In-plane switching).

32, the pretilt of the molecule in one electric field polarity E has a uniform distribution across the nematic bulk 24, while the other one has an electric field polarity E ), The nematic bulk 24 employs a splay transformation resulting in a flex-inherent polarization (P _flexo ). However, similar to the spontaneous polarization (P _s ) of the FLCP layer, the flake inherent polarization (P _flexo ) is linearly coupled to the electric field (E) resulting in in-plane switching.

Similar to Embodiments 1 and 2, the total switching time (τ _rise + τ _fall ) was found to be about 8-12 ms when the applied voltage was 25V.

If less than the pre-tilt (θ _β) from the pre-tilt (θ _α) of the substrate (21) fitting the electrodes 23 on the substrate 22 without the electrodes 23, the strongest Plectranthus own conductive polarization ( P _flexo will be localized at the surface 21 that actually _{engages the} electrode pattern 23 thereby providing a stronger coupling to the applied electric field E and a more effective switching of the nematic 24 Shorter switching times).

Example 4

The electrodes Chiral Smyth The alignment layer  Cells Containing

The cell used in this embodiment (Fig. 34) has the same structure as that used in Example 3. However, in this embodiment, the two inner surfaces of the substrates 25 and 26 are aligned in a single direction along the electrode pattern 27 to promote pre-tilt (&amp;thetas;) &lt; Not shown) (Fig. 34). In addition, an FLCP layer (not shown) is aligned with the smectic layers in parallel to the substrate 25.

34, the pretilt of the molecule at one electric field polarity E has a uniform distribution across the nematic bulk 28, while at the other electric field polarity E the nematic bulk 28 ) Employs a bend strain resulting in a flex inherent polarization (P _flexo ), as shown in Figure 35, and the flex propulsive polarization (P _flexo ) is linearly coupled to the electric field (E) Plane switching.

Switching of the FLCP layer is schematically illustrated in Figures 36A and 36B.

The switching of the nematic bulk 28 including the switching time was found to be similar to the switching described in Example 3.

Example 5

Hybrid alignment with comb-like electrodes to generate fringe fields ( HAN ) &Lt; / RTI &gt;

In this embodiment (Fig. 37), a sandwich cell is used comprising two parallel glass substrates 29 and 30 forming a cell gap of about 2 m. An electrode pattern including a first conductive layer 31, an insulating layer 32 having a thickness of about 300 nm and a second conductive layer 33 having a comb-like shape is formed on the inner surface of one of the substrates 29 (Sectional device) (Fig. 37). The distribution of the components of the fringe electric field produced by this electrode pattern is schematically illustrated in Fig.

A first alignment layer 34 made of Nissan SE1211 promoting the vertical orientation of the liquid crystal bulk layer 35 provided in the cell gap is formed on the substrate 29 sandwiching the comb-like electrode 33, .

A second alignment layer 36 made of Nissan SE-2170 rubbed parallel to the electrodes 31 and 33 to promote a uniform planar orientation of the liquid crystal bulk layer 35 provided in the cell gap, as in Example 2 Are disposed on the inner surface of the other substrate 30.

As in Example 2, the cell gap is filled with another nematic liquid crystal material MDA-05-187, which has a negative dielectric anisotropy (DELTA epsilon < 0).

Thus, the nematic liquid crystal 35 filling the cell gap employs the HAN structure (Figs. 37 and 38) and the strongest flake _inherent polarization (P _flexo ) near the substrate 29, which sandwiches the comb- ) Is localized. 38 to 40, both arrows indicate the direction of the sample optical axis.

39 and 40, the parallel components of the fringe electric field E are arranged such that in the in-plane the flex-inherent polarization (P _flexo ) adjacent to the two parallel sides of the comb-like electrode 33 Clockwise and counterclockwise, thereby resulting in a substantial electro-optical response.

However, as shown in Figs. 41 and 42, the component perpendicular to the fringe electric field E has an out-of-plane electric field at the middle between two parallel sides of the comb-like electrode 33, _{Switches the} polarization (P _flexo ), but this does not result in an electro-optic response.

The display image of such a device has a high contrast ratio, where FIG. 43 shows the electric field-on state and FIG. 44 shows the electric field-off state.

Additionally, due to in-plane switching, the device also has a wide viewing angle.

Also, the voltage required to drive the switching of the nematic bulk 35 in this device is about 6V, which is much smaller than the voltage (15-20V) required for a conventional IPS display.

The total switching time (τ _rise + τ _fall ) of these devices was found to be about 3 ms. The rise time (τ _rise ) is about 2 ms and the fall time (τ _fall ) is about 0.9 ms. Therefore, the switching time is much shorter than the conventional IPS display.

Example 6

Hybrid alignment with comb-like electrodes to generate fringe fields ( HAN ) &Lt; / RTI &gt;

Although the same type of sandwich cell as in Example 5 is used in this embodiment, the HAN texture is reversed. Thus, the alignment in the substrate on which the electrodes are sandwiched is planar, and the alignment in the opposite substrate is vertical (i. E., Similar to embodiment 1).

In addition, as used in Example 1, the cell gap is filled with another nematic liquid crystal material MLC 16000-000 (provided by Merck) with positive dielectric anisotropy (??> 0).

As in Example 1, the nematic liquid crystals adopt the HAN structure and localize the strongest flake inherent polarization (P _flexo ) near the substrate having the comb-like electrode.

Switching of nematic, including switching time, was found to be similar to the switching described in Example 5.

Example  7

A comb-like electrode for generating a fringe electric field Chiral Smyth The alignment layer  Cells Containing

The cell used in this embodiment (FIG. 45) has the same structure as that used in Example 5. However, in this embodiment, the two inner surfaces of the substrates 37 and 38 are aligned with the alignment layers 39 and 39 of the Nissan SE-2170 rubbed parallel to the comb-like electrode 41 to promote planar alignment in a single direction. 40).

A thin film dielectric liquid crystal polymer (FLCP) 43, more specifically a ferroelectric side-chain polysiloxane, is disposed on top of the alignment layer 39 covering the electrodes 41 and 42. The FLCP layer 43 is aligned with the bookcase shape, i.e., the smectic layers parallel to the substrate surface 37. The cell gap is filled with a nematic liquid crystal material 44 prepared in-house that is not mixable (not dissolved) in the FLCP 43 with negative dielectric anisotropy (DELTA epsilon < 0).

As in Example 3, the electric field E does not directly switch the nematic molecules 44 due to negative dielectric anisotropy. The electric field E, however, switches the molecules of the FLCP 43 by spontaneous polarization of the FLCP material 43 which in turn switches the nematic liquid crystal molecules 44 of the bulk layer by the elastic force (in-plane switching ) (See WO 00/03288) (Figs. 47 and 48).

51, switching the FLCP molecules 43 by applying an electric field E applies an electric field (i.e., an electric field generated between the electrodes applied on the individual substrate surfaces) over the entire bulk It was found to be more efficient than switching. 51 comprises ITO electrodes 45 and 46, respectively, applied on each of the substrate surfaces 47 and 48 and FLCP layers 49 and 50 applied on the ITO electrodes 45 and 46, . The cell gaps separated by the spacers 51 are filled with the biquadratic nematic liquid crystal material 52.

The contrast ratio of the display image of the device by the fringe electric field is seen to have a much greater contrast ratio than the display image of the device by the electric field generated over the entire bulk layer (see FIGS. 49 and 50).

Also, the drive voltage, which is about 6.7 V of the device by the fringe field, is much smaller than the drive voltage of about 50 V of the device due to the electric field generated across the bulk layer (due to the nature of the measurement device, Must be multiplied).

Example  8

A comb-like electrode for generating a fringe electric field Chiral Smyth The alignment layer  Cells Containing

Example 7 is repeated, but only the nematic liquid crystal material exhibits a positive dielectric anisotropy (??> 0).

Example  9

A comb-like electrode for generating a fringe electric field Chiral Smyth The alignment layer  Cells Containing

Example 7 is repeated, but the FLCP layer is aligned with the smectic layers parallel to the substrate surface. The expected switching of the FLCP is shown in Figures 53 and 54.

Example  10

A comb-like electrode for generating a fringe electric field Chiral Smyth The alignment layer  Containing Cells (Double-Sided Devices)

Example 7 is repeated except that the inner surfaces of each of the substrates 53 and 54 engage the electrode patterns 55 and 56 described above to create fringe electric fields near the two substrate plates 53 and 54 Device) (Fig. 55). Each substrate surface 53 and 54 also faces a respective non-cir- cular nematic liquid crystal bulk layer 61 and each has a passive alignment layer 57 and 58 and an FLCP Lt; / RTI &gt; layers 59 and 60, respectively.

Example  11

A comb-like electrode for generating a fringe electric field Chiral Smyth The alignment layer  Containing Cells (Double-Sided Devices)

Example 8 is repeated, except that the two inner surfaces of the substrates undergo the electrode pattern described above to produce fringe electric fields near the two substrates (two-sided device).

Example  12

A comb-like electrode for generating a fringe electric field Chiral Smyth  A cell (a double-sided device)

Example 7 is repeated, except that the inner surface of each of the substrates has the electrode pattern described above (duplex device), and each substrate surface includes a passive alignment layer. However, instead of each alignment layer being coated with an FLCP layer, chiral molecules (chiral dopants) are attached to the alignment layer. In addition, the cell gap is filled with the bicalyalmic liquid crystal material. The chiral molecules induce chirality in the sub-volume of the non-chiral smectic bulk layer and thereby induce a switchable ferroelectric sub-volume near the substrate containing the comb-like electrode.

While the invention has been described in detail and with reference to specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention something to do.

Claims (24)

A first and a second confining substrate; A liquid crystal bulk layer disposed between the substrates, wherein the liquid crystal comprises a nematic liquid crystal material exhibiting flake inherent polarization under its elastic deformation; A first electrode pattern applied on an inner surface of the first substrate; A first alignment layer applied on the first electrode pattern and arranged to interact with the bulk layer at a bulk surface; And - a second alignment layer arranged on the second substrate to interact with the bulk layer at the bulk surface, As a liquid crystal device, Wherein one of the first alignment layer and the second alignment layer is configured to promote homeotropic alignment of the bulk layer and wherein the other of the first alignment layer and the second alignment layer has a uniform plane &Lt; RTI ID = 0.0 &gt; alignment, Wherein the first electrode pattern is arranged to produce a non-uniform electric field across a first sub-volume of the bulk layer adjacent the first alignment layer, the electric field having a non-uniform direction and intensity of electric lines, Planar field lines in directions parallel to the inner surface of the first substrate and perpendicular to the polarization orientation of the bulk layer, the electric field is also generated over the first alignment layer, In the liquid crystal device, The polarization of the liquid crystals being selected from the group consisting of (i) a first sub-volume of the first sub-volume, and (ii) a second sub-volume of the liquid crystal bulk layer adjacent to the second substrate, Further comprising liquid crystals outside the second sub-volume of the bulk layer, the liquid crystals being stronger than any possible similar liquid crystal polarization of the bulk layer; The liquid crystals in the polarization state contained in the first sub-volume are switched, at least in part, by the coupling between the electric field and the polarization, so that in-plane switching of the liquid crystals of the bulk layer is achieved by the elastic force Features, Liquid crystal device. The method according to claim 1, A second electrode pattern is applied on the inner surface of the second substrate to create a non-uniform electric field across the second sub-volume of the bulk layer adjacent to the second electrode pattern, And the strength is uneven, Wherein the second alignment layer is formed on the second electrode pattern, Liquid crystal device. The method of claim 1, wherein the polarization in the first alignment layer A second sub-volume of the first sub-volume and a second sub-volume of the second sub-volume, Liquid crystal device. The method of claim 3, The coupling between the liquid crystals in the electric and polarized states, A ferroelectric coupling, a ferroelectric coupling, an antiferroelectric coupling, a phase dielectric coupling, a flexoelectric coupling, and any combination thereof. Liquid crystal device. 5. The method of claim 4, The coupling between the liquid crystals in the electric and polarized states, The ferroelectric coupling, Liquid crystal device. 6. The method of claim 5, Wherein at least one of the first alignment layer and the second alignment layer comprises a liquid crystal material exhibiting spontaneous polarization. Liquid crystal device. The method according to claim 6, Wherein at least one of the first alignment layer and the second alignment layer comprises a chiral smectic C (SmC ^* ) liquid crystal material. Liquid crystal device. 5. The method of claim 4, Wherein the liquid crystal material exhibiting spontaneous polarization in at least one of the first alignment layer and the second alignment layer comprises a liquid crystal polymer capable of forming a ferroelectric coupling, an antiferroelectric coupling or a paraelectric coupling, or a combination thereof, sign, Liquid crystal device. 6. The method of claim 5, Wherein the chiral dopants are non-uniformly distributed within the bulk layer as a result of permanently attaching to at least one surface in the first sub-volume and thereby inducing a local increase in one or more chirality-related properties within the first sub- Wherein the chiral dopants are distributed in the liquid crystal bulk layer and are soluble in the liquid crystal bulk layer, resulting in a spontaneous polarization having a non-uniform distribution decreasing in a direction that is maximum at the surface and away from the surface, Liquid crystal device. 5. The method of claim 4, The coupling between the liquid crystals in the electric and polarized states, The flake possesses the inherent coupling, Liquid crystal device. 11. The method of claim 10, The dopants are non-uniformly distributed in the bulk layer as a result of being permanently attached to at least one surface in the first sub-volume and thereby promoting a local increase of one or more properties within the first sub-volume, Wherein the dopant is present in the liquid crystal bulk layer and is soluble in the liquid crystal bulk layer, Liquid crystal device. 12. The method of claim 11, Selected from the group consisting of bananas-type, bananas-type, drop-type, drop-banana hybrid-type dopants and any combination of two or more thereof. Liquid crystal device. 11. The method of claim 10, The coupling between the liquid crystals in the electric and polarized states, A combination of flake-inherent coupling and dielectric coupling, Liquid crystal device. delete The method of claim 1, wherein the polarization of the first sub- Volume, which is caused by varying alignment control characteristics of the first alignment layer or protrusions that extend into the first sub- A splay transformation or a bend transformation in the liquid crystal bulk layer or a combination thereof, Liquid crystal device. The method according to claim 1, The liquid crystal bulk layer exhibits a splay-bend hybrid deformation, volume liquid crystals exhibit a bend strain when e _b is the major flex-specific conductivity coefficient of the first sub-volume of the flake inherent polarization, Liquid crystal device. The method according to claim 1, The liquid crystal bulk layer exhibiting a splay-bend hybrid transformation, e _s is the first sub-conductive when the main Plectranthus own coefficient of volume Plectranthus own conductive polarization of the first sub-volume of the liquid crystal display are shown the variations, Liquid crystal device. The method according to claim 1, Wherein the liquid crystal bulk layer exhibits positive dielectric anisotropy and splay deformation and the electrode pattern applied on the inner side of each substrate causes an uneven electric field across each sub-volume of the bulk layer adjacent to the electrode patterns Generated, Liquid crystal device. The method according to claim 1, Wherein the liquid crystal bulk layer exhibits negative dielectric anisotropy and bend strain and an uneven electric field across each sub-volume of the bulk layer adjacent to the electrode patterns due to the electrode pattern applied on the inner surface of each substrate Generated, Liquid crystal device. 3. The method of claim 2, Wherein at least one of the first electrode pattern and the second electrode pattern includes electrodes interdigitated with each other, Liquid crystal device. 3. The method of claim 2, Wherein at least one of the first electrode pattern and the second electrode pattern comprises fringe- Liquid crystal device. 22. The method of claim 21, Wherein at least one of the first electrode pattern and the second electrode pattern comprises a first conductive layer arranged on each of the first and second substrates, an insulating layer arranged on the first conductive layer, And a second conductive layer arranged on the first conductive layer, The second conductive layer may have a comb-like shape, Liquid crystal device. 22. The method of claim 21, Wherein at least one of the first electrode pattern and the second electrode pattern includes a first conductive layer arranged on a corresponding first substrate, a second substrate or first and second substrates, and an insulating layer disposed on the first conductive layer, And a second conductive layer arranged on the top of the insulating layer, Wherein the second conductive layer has openings, Liquid crystal device. delete

Images