JP2003165978A - Organic semiconductor liquid crystal composition and organic semiconductor liquid crystal element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an organic semiconductor liquid crystal composition which utilizes the memory properties, molecular arrangement state, and field responsivity of a liquid crystal exhibiting a cholesteric phase; and to provide an organic semiconductor liquid crystal element using the same. <P>SOLUTION: In each of organic semiconductor liquid crystal elements 1A, 1B, 2A, 2B, and 2C, the organic semiconductor liquid crystal composition LC comprising a liquid crystal exhibiting a cholesteric phase and an organic semiconductor compound contained therein is put between at least a pair of electrodes 15 and 16. Each of the organic semiconductor liquid crystal elements has such semiconductor characteristics that, when the molecular arrangement of the liquid crystal exhibiting the cholesteric phase is in a stable state of planar arrangement or focal conic arrangement, electric current flows in at least the optical axis direction X of the liquid crystal molecular arrangement by applying an electric field and does not flow in at least the direction Y crossing the optical axis direction X at right angles. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an organic semiconductor liquid crystal composition and an organic semiconductor liquid crystal device.

[0002]

2. Description of the Related Art A liquid crystal element usually includes a pair of electrodes and a liquid crystal sandwiched between these electrodes. The alignment of liquid crystal molecules can be controlled by applying a driving voltage to the liquid crystal.

As a liquid crystal element, for example, a liquid crystal element using a cholesteric liquid crystal exhibiting a cholesteric phase is known.

In recent years, various studies have been made on liquid crystal devices using a liquid crystal exhibiting a cholesteric phase such as a chiral nematic liquid crystal composition which exhibits a cholesteric phase at room temperature by adding a chiral material to nematic liquid crystal.

In a liquid crystal element using such a liquid crystal exhibiting a cholesteric phase, the liquid crystal can be switched between a planar molecular alignment state and a focal conic molecular alignment state by applying high and low pulse voltages. Even after the application of the pulse voltage is stopped, the planar molecule alignment state, the focal conic molecule alignment state, or the mixed state thereof is maintained, which is so-called bistability or memory property.

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention have searched for an application field by utilizing the memory property of a liquid crystal exhibiting such a cholesteric phase, the molecular alignment state and its electric field responsiveness, and searched for an application field to align the liquid crystal molecules. We have conducted research on organic semiconductor liquid crystal compositions and organic semiconductor liquid crystal devices that can expect semiconductor characteristics from the state.

It is an object of the present invention to provide an organic semiconductor liquid crystal composition which takes advantage of the memory properties of liquid crystals exhibiting a cholesteric phase, the molecular alignment state and the electric field response thereof.

It is another object of the present invention to provide an organic semiconductor liquid crystal device which makes the best use of the characteristics of the memory properties of liquid crystals exhibiting a cholesteric phase, the state of molecular alignment and the electric field response thereof.

[0009]

Means for Solving the Problems The inventors of the present invention have made the following studies and found the following. That is, a liquid crystal that forms a cholesteric phase and in which the orientation of the helical axis of liquid crystal molecules changes due to the application of an electric field or pressure, for example, when present between a pair of electrodes, the helical axis is perpendicular to the electrode. To a liquid crystal having a substantially vertical molecular alignment of a planar alignment and a parallel or substantially parallel molecular alignment of a focal conic alignment, a compound that forms a charge transfer complex (hereinafter referred to as “charge transfer complex formation”) in the liquid crystal. Compound)) or an organic semiconductor compound such as a compound in which charge transfer occurs by intermolecular hopping conduction, so that the semiconductor characteristics depending on the alignment change of liquid crystal molecules, more specifically, the cholesteric phase When the molecular alignment of the liquid crystal shown is in the stable state of the planar alignment or the focal conic alignment, at least the optical axis direction of the liquid crystal molecular alignment, In other words, by applying an electric field in the direction of the helical axis of the liquid crystal molecules, a current flows, and at least in the direction orthogonal to the optical axis direction of the liquid crystal molecule alignment, in other words, in the direction orthogonal to the direction of the helical axis of the liquid crystal molecules. It has been found that it has a semiconductor characteristic of exhibiting insulating properties.

The charge transfer complex is a molecule-pair complex formed by positive and negative charge transfer when an electron-donating molecule and an electron-accepting molecule are adjacent to each other. Means that when the molecules are adjacent to each other,
This is a phenomenon in which charge transfer occurs due to the overlap of molecular orbitals.

The present invention is based on such findings,
The following organic semiconductor liquid crystal composition and organic semiconductor liquid crystal device are provided. (1) Organic semiconductor liquid crystal composition An organic semiconductor liquid crystal composition comprising an organic semiconductor compound in a liquid crystal exhibiting a cholesteric phase. (2) Organic semiconductor liquid crystal element At least when the organic semiconductor liquid crystal composition is sandwiched between at least a pair of electrodes, and the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in a stable state of planar alignment or focal conic alignment. A current flows by applying an electric field in the optical axis direction of the liquid crystal molecule array (in other words, the direction of the spiral axis of the liquid crystal molecules), and at least the optical axis direction of the liquid crystal molecule array (in other words, the direction of the spiral axis of the liquid crystal molecules) An organic semiconductor liquid crystal device having a semiconductor property of exhibiting an insulating property in a direction orthogonal to.

The liquid crystal exhibiting the cholesteric phase is a liquid crystal forming the cholesteric phase, and a liquid crystal in which the alignment state of the helical axes of the liquid crystal molecules is changed by the application of an electric field or pressure, for example, a driving voltage for changing the molecular alignment of the liquid crystal is When present between a pair of applied electrodes, it shows a molecular arrangement of a planar arrangement in which the helical axis is perpendicular to or substantially perpendicular to the electrodes and a molecular arrangement of a focal conic arrangement in which the helical axes are parallel to or substantially parallel to the electrodes. It is a liquid crystal.

Typical examples of the liquid crystal exhibiting the cholesteric phase include a cholesteric liquid crystal and a chiral nematic liquid crystal composition. Examples of the chiral nematic liquid crystal composition include those that can be obtained by adding a chiral dopant (chiral material) capable of forming a cholesteric phase to the nematic liquid crystal composition.

In the organic semiconductor liquid crystal composition according to the present invention and the organic semiconductor liquid crystal device according to the present invention, since the organic semiconductor compound is contained in the liquid crystal exhibiting the cholesteric phase, the semiconductor according to the arrangement change of the liquid crystal molecules. Characteristic, that is, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in a stable state of planar alignment or focal conic alignment, an electric field is applied at least in the optical axis direction of the liquid crystal molecular alignment, in other words, in the direction of the helical axis of the liquid crystal molecules. By doing so, a current flows, and at least a direction orthogonal to the optical axis direction of the liquid crystal molecule alignment, in other words, a direction orthogonal to the direction of the helical axis of the liquid crystal molecules, has a semiconductor characteristic of insulating properties.

The main reasons for exhibiting such semiconductor characteristics are as follows. That is, in the liquid crystal exhibiting the cholesteric phase, the liquid crystal molecules a are formed in a layered structure as shown in FIG. 6, and the major axes of the molecules a are arranged in parallel in the layer A. The direction of the molecular axis of each layer A is slightly deviated from the direction of the molecular axis of the adjacent layer to form a spiral structure as a whole. In such a liquid crystal, normally, insulation is exhibited both between adjacent layers A and inside each layer A. When an organic semiconductor compound coexists in this liquid crystal, an electric field is applied between adjacent layers A, in other words, in the optical axis direction X of the liquid crystal molecule alignment (direction of the spiral axis B of the liquid crystal molecule a). Charge transfer occurs due to the overlap of molecular planes. On the other hand, in each layer A, in other words, the insulating property remains in the direction Y orthogonal to the optical axis direction (direction of the spiral axis B of the liquid crystal molecules a) X of the liquid crystal molecule alignment. As a result, a current flows by applying an electric field in at least the optical axis direction (the spiral axis direction) X, and at least a direction Y orthogonal to the optical axis direction (the spiral axis direction) X.
Is considered to exhibit insulating properties.

Typical examples of the organic semiconductor liquid crystal composition according to the present invention and the organic semiconductor compound which can be used in the organic semiconductor liquid crystal device according to the present invention include charge transfer complex-forming compounds and charge transfer intermolecular hopping. Mention may be made of compounds that occur in conduction.

In the organic semiconductor liquid crystal device according to the present invention, in order to enable liquid crystal driving, a conductive voltage (charge extraction) showing the semiconductor characteristic is more than driving voltage Vl for changing the molecular arrangement of the liquid crystal showing the cholesteric phase. Voltage)
It is desirable to make Vs smaller. That is, it is desirable that the relationship between the drive voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase and the conduction voltage (charge extraction voltage) Vs exhibiting the semiconductor characteristics is Vl> Vs.

[0018] As the drive voltage Vl to change the molecular arrangement of the liquid crystal exhibiting the cholesteric phase, a smaller drive voltage Vl ₁ and the drive voltage Vl ₁ to change the molecular arrangement of the liquid crystal in a planar array showing the cholesteric phase A driving voltage V which is a voltage and changes the molecular arrangement of the liquid crystal exhibiting the cholesteric phase into a focal conic arrangement.
l ₂ can be exemplified. In this case, the above relationship is Vl ₁ > V
l ₂ > Vs.

For example, when the driving voltage Vl ₁ is applied to the organic semiconductor liquid crystal composition, the molecular alignment of the liquid crystal exhibiting the cholesteric phase becomes a planar alignment, and when the driving voltage Vl ₂ is applied, the cholesteric phase is formed. The molecular alignment of the liquid crystal shown is a focal conic alignment. The planar alignment state and the focal conic alignment state of the liquid crystal can be maintained even after the voltage is applied.

Examples of the organic semiconductor liquid crystal device according to the present invention include the following. That is, (a) an organic semiconductor liquid crystal element having a planar electrode structure: a pair of liquid crystal driving electrodes for applying a driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase; A pair of conductive (charge extraction) electrodes for applying a charge extraction voltage) Vs, and the liquid crystal driving electrode is provided outside the conductive (charge extraction) electrode. An organic semiconductor liquid crystal element, which is provided in parallel or substantially parallel to the (outgoing) electrode and is in non-contact with the conductive (outgoing charge) electrode sandwiching the organic semiconductor liquid crystal composition.

In this case, the liquid crystal driving electrode may be provided on the conductive (charge extraction) electrode via an insulating layer.

In this electrode structure, the liquid crystal driving electrode and the conductive (charge extracting) electrode are parallel or substantially parallel to each other, and the conductive (charge extracting) electrode is in contact with the organic semiconductor liquid crystal composition. is doing. A driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase between the liquid crystal driving electrodes, for example, a driving voltage Vl ₁ for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase into a planar arrangement or a focal conic arrangement. The drive voltage Vl ₂ that changes to Further, a conduction voltage (charge extraction voltage) Vs exhibiting the semiconductor characteristics is applied between the conduction (charge extraction) electrodes.

When the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the planar alignment, the helical axis of the liquid crystal molecules in the planar alignment is perpendicular to or substantially perpendicular to the liquid crystal driving electrode, It is also perpendicular or substantially perpendicular to the conductive (charge extraction) electrode which is parallel or substantially parallel to the electrode. When a conduction voltage (charge extraction voltage) Vs is applied between the electrodes for conduction (charge extraction) perpendicular to or substantially perpendicular to the spiral axis of the liquid crystal molecules, the optical axis direction of the liquid crystal molecule alignment (that is, the spiral axis of the liquid crystal molecules The electric field can be applied in the (direction). At this time, a current flows between the conductive (charge extraction) electrodes that are in contact with the organic semiconductor liquid crystal composition.

On the other hand, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the helical axis of the liquid crystal molecules in the focal conic alignment is parallel or substantially parallel to the liquid crystal driving electrode, It is also parallel or substantially parallel to the conductive (charge extraction) electrode which is parallel or substantially parallel to the liquid crystal driving electrode. Conduction voltage (charge extraction voltage) between conductive (charge extraction) electrodes parallel or substantially parallel to the spiral axis of the liquid crystal molecule.
When Vs is applied, an electric field can be applied in a direction orthogonal to the optical axis direction of the liquid crystal molecule alignment (that is, the direction of the spiral axis of the liquid crystal molecules). At this time, the conductive (for extracting charges) electrodes that are in contact with the organic semiconductor liquid crystal composition show insulation.

In the case of this flat type electrode structure, a memory-having semiconductor pattern (a liquid crystal pattern having the above-mentioned semiconductor characteristics) can be formed by utilizing the memory property of the liquid crystal exhibiting the cholesteric phase. (B) Organic semiconductor liquid crystal device having a three-dimensional electrode structure (b-1) Organic semiconductor liquid crystal device having a first three-dimensional electrode structure A pair for applying a drive voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase At least two sets of electrodes, one set for liquid crystal driving electrodes and one set for conducting (charge extraction) electrodes for applying the conduction voltage (charge extraction voltage) Vs exhibiting the semiconductor characteristics. An organic semiconductor liquid crystal element in which the liquid crystal driving electrode and the conductive (charge extraction) electrode are arranged in a direction perpendicular to or substantially perpendicular to each other and the organic semiconductor liquid crystal composition is sandwiched therebetween.

In this electrode structure, the liquid crystal driving electrode and the conductive (charge extracting) electrode are perpendicular to or substantially perpendicular to each other, and the conductive (charge extracting) electrode is in contact with the organic semiconductor liquid crystal composition. is doing. Then, a drive voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase between the liquid crystal driving electrodes, for example, a drive voltage Vl ₁ for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase into a planar arrangement or a focal conic. A drive voltage Vl ₂ that changes the arrangement is applied. Further, a conduction voltage (charge extraction voltage) Vs exhibiting the semiconductor characteristics is applied between the conduction (charge extraction) electrodes.

In the first three-dimensional electrode configuration, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the desired orientation of the liquid crystal molecule is that the helical axis of the liquid crystal molecule is the conductive layer. For example, the orientation may be vertical or substantially vertical to the working (charge extraction) electrode.

In the orientation of the liquid crystal molecules, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the helical axis of the liquid crystal molecules is parallel to the liquid crystal driving electrode in the focal conic alignment. Although it is substantially parallel, as described above, it is perpendicular or substantially perpendicular to the conductive (charge extraction) electrode. Conduction voltage (charge extraction voltage) between conductive (charge extraction) electrodes perpendicular to or substantially perpendicular to the helical axis of the liquid crystal molecule.
When Vs is applied, an electric field can be applied in the optical axis direction of the liquid crystal molecule alignment (that is, the direction of the spiral axis of the liquid crystal molecules). At this time, a current flows between the conductive (charge extraction) electrodes that are in contact with the organic semiconductor liquid crystal composition.

On the other hand, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in a stable state of the planar alignment, the helical axis of the liquid crystal molecules in the planar alignment is perpendicular to or substantially perpendicular to the liquid crystal driving electrode, and the liquid crystal It is parallel or substantially parallel to the conductive (charge extraction) electrode which is perpendicular to or substantially perpendicular to the driving electrode. When a conduction voltage (charge extraction voltage) Vs is applied between the electrodes for conduction (charge extraction) parallel or substantially parallel to the spiral axis of the liquid crystal molecules, the liquid crystal molecule alignment direction (that is, the spiral axis of the liquid crystal molecules The electric field can be applied in a direction orthogonal to the (direction). At this time, the conductive (for extracting charges) electrodes that are in contact with the organic semiconductor liquid crystal composition show insulation.

Further, as described below, two or more sets of conductive (charge extraction) electrodes may be provided, or two or more sets of conductive (charge extraction) electrodes and liquid crystal driving electrodes may be provided. . (B-2) Organic semiconductor liquid crystal element having a second three-dimensional electrode structure A pair of liquid crystal driving electrodes for applying a driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase, and a conductivity exhibiting the semiconductor characteristics. A pair of first conductive (charge extraction) electrodes for applying a voltage (charge extraction voltage) Vs and a pair of first electrodes for applying a conductive voltage (charge extraction voltage) Vs exhibiting the semiconductor characteristics. Two
The conductive (charge extraction) electrode includes at least two sets of electrodes, and the liquid crystal driving electrode includes the first set of electrodes.
It is provided outside the conductive (charge extraction) electrode in parallel or substantially parallel to the first conductive (charge extraction) electrode and in a non-contact manner, and is provided for the first and second conductive ( An organic semiconductor liquid crystal device in which electrodes for charge extraction) are arranged in a direction perpendicular to or substantially perpendicular to each other and the organic semiconductor liquid crystal composition is sandwiched therebetween.

In this case, the liquid crystal driving electrode is the first
It may be provided on the conductive (charge extraction) electrode via an insulating layer. (B-3) Third Semiconductor Electrode Liquid Crystal Element Having Three-Dimensional Electrode Structure A pair of first liquid crystal driving electrodes for applying a driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase and the semiconductor characteristics are set. In order to apply a driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase, a pair of first conducting (charge extracting) electrodes for applying the conducting voltage (charge extracting voltage) Vs shown A pair of second liquid crystal driving electrodes and a pair of second conductive (charge extraction) electrodes for applying a conductive voltage (charge extraction voltage) Vs showing the semiconductor characteristics, and at least two sets of electrodes And the first and second liquid crystal driving electrodes are provided outside the first and second conductive (charge extraction) electrodes, respectively. Is provided in parallel to or substantially parallel to, and in non-contact with, the first and second conductive (charge extraction) electrodes are arranged in a direction perpendicular to or substantially perpendicular to each other, and the organic semiconductor liquid crystal is provided. An organic semiconductor liquid crystal device in which the respective compositions are sandwiched.

In this case, the first and second liquid crystal driving electrodes may be provided on the first and second conductive (charge extraction) electrodes via an insulating layer, respectively.

In any case, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, conversion to the planar alignment may be performed by applying pressure to the organic semiconductor liquid crystal composition. When the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, when a pressure is applied to the organic semiconductor liquid crystal composition, the helical axes of the liquid crystal molecules are aligned in the pressure direction, and the pressure is applied. A planar array of liquid crystal molecules is formed at the portion. As described above, the planar alignment of the liquid crystal molecules is also formed by the pressure applied to the organic semiconductor liquid crystal composition, so that the pressed portion exhibits conductivity at least in the direction of the helical axis of the liquid crystal molecules. In this case, the liquid crystal driving electrode may not be provided.

The planar arrangement of the liquid crystal molecules exhibiting the cholesteric phase may have a selective reflectivity for light having a predetermined wavelength (for example, light having a visible wavelength). In this case, since the organic semiconductor liquid crystal composition and the organic semiconductor liquid crystal element of the present invention flow a current at least by applying an electric field in the optical axis direction of the liquid crystal molecule alignment (that is, the direction of the helical axis of the liquid crystal molecules), the semiconductor part The (part showing the semiconductor characteristics) can be used as a colored part by selective reflectivity to determine the energized state, and can also be used as an image display part.

The organic semiconductor liquid crystal composition of the present invention is
It can be applied and developed to a device utilizing charge transfer, for example, a substitute for an electrophotographic photosensitive member that exhibits conductivity by light irradiation, a sensor such as a pressure sensor or an optical sensor, and the like.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing a schematic structure of an example of an organic semiconductor liquid crystal element, and FIG. 1A is a planer when a driving voltage for changing the molecular arrangement of liquid crystals showing a cholesteric phase into a planar arrangement is applied. FIG. 1B is a diagram showing an alignment state, and FIG. 1B is a diagram showing a focal conic alignment state when a drive voltage for changing the molecular alignment of liquid crystal exhibiting a cholesteric phase to a focal conic alignment is applied.

In the organic semiconductor liquid crystal element 1A shown in FIG. 1, the organic semiconductor liquid crystal composition LC is sandwiched between at least a pair of electrodes (conducting electrodes 15 and 16 in this case), and the molecular alignment of liquid crystal showing a cholesteric phase. Is in the stable state of the planar alignment or the focal conic alignment, a current flows by applying a conductive electric field at least in the optical axis direction of the liquid crystal molecule array (direction of the spiral axis B of the liquid crystal molecule a) (X direction in the figure). , At least in the optical axis direction of the liquid crystal molecule alignment (the liquid crystal molecule a
In the direction (Y direction in the drawing) orthogonal to X direction of the spiral axis B), the semiconductor characteristics exhibit insulating properties.

The organic semiconductor liquid crystal element 1A has a planar electrode structure and includes a pair of substrates 11 and 12.

A driving voltage Vl for changing the molecular arrangement of liquid crystals exhibiting a cholesteric phase is provided on the substrates 11 and 12, respectively.
A pair of liquid crystal driving electrodes 13 and 14 for applying a voltage are formed. An insulating layer 1 is formed on the electrodes 13 and 14, respectively.
The charge extraction voltage Vs exhibiting the semiconductor characteristics via
A pair of charge extracting (conducting) electrodes 15 and 16 for applying a voltage are formed.

The substrates 11 and 12 are arranged so that their electrode forming surfaces face each other, and the organic semiconductor liquid crystal composition LC is sandwiched between the substrates 11 and 12.

The organic semiconductor liquid crystal composition LC comprises an organic semiconductor compound in a liquid crystal exhibiting a cholesteric phase.

The liquid crystal exhibiting a cholesteric phase is a liquid crystal forming a cholesteric phase, and the liquid crystal in which the arrangement state of the helical axis B of the liquid crystal molecules a is changed by the application of an electric field or pressure. In this case, driving for changing the molecular alignment of the liquid crystal. A pair of substrates 11 having electrodes 13 and 14 to which a voltage Vl is applied,
12 is a liquid crystal showing a molecular arrangement of a planar arrangement in which the spiral axis B is perpendicular to or substantially perpendicular to 12 and a molecular arrangement of a focal conic arrangement in which the spiral axis B is parallel or substantially parallel.

The liquid crystal exhibiting the cholesteric phase is a chiral nematic liquid crystal composition which can be obtained by adding a chiral dopant capable of forming a cholesteric phase to the nematic liquid crystal composition. In this chiral nematic liquid crystal composition, the planar alignment of the liquid crystal molecules a exhibiting a cholesteric phase here has a selective reflection ability for visible wavelength light. The organic semiconductor compound added to the nematic liquid crystal composition is here a charge transfer complex-forming compound or a compound in which charge transfer takes place by intermolecular hopping conduction. (Nematic Liquid Crystal Composition) A nematic liquid crystal composition that can be used for forming a chiral nematic liquid crystal composition is a nematic liquid crystal composition that can express a cholesteric liquid crystal phase by forming a helical structure of liquid crystal molecules by adding a chiral dopant, Either may be used. A polymer nematic liquid crystal (main chain type or side chain type polymer nematic liquid crystal) can also be used.

As the nematic liquid crystal composition, for example,
Benzylideneaniline, azobenzene, azoxybenzene, cyanobiphenyl, cyanoterphenyl, phenylcyclohexane, biphenylcyclohexane, benzoic acid ester, cyclohexylcyclohexane, cyclohexylcarboxylic acid ester, phenylpyrimidine, phenyldioxane, cyclohexylethane, cyclohexene, difluorophenylene, tolan, etc. It is possible to use one kind or a mixture of two or more kinds of nematic liquid crystal compounds having the chemical structure of. Further, it may be a polymer liquid crystal that forms a nematic phase. Furthermore, cholesteryl chloride, cholesteryl bromide, cholesteryl benzoate, cholesteryl palmitate, cholesteryl hexyl ether, and other cholesterol derivatives can also be used together. (Chiral dopant) As a chiral dopant,
Various conventionally known compounds having an optically active site can be used, and examples thereof include compounds having a 2-methylbutyl, 2-methylbutoxy, 4-methylhexyl group or the like as an optically active group. It may be a compound having a skeleton similar to that of the above nematic liquid crystal compound. The chiral dopant may or may not be liquid crystalline. Further, it may be a compound having a plurality of optically active sites in the same molecule, or may be a polymer compound having an optically active site. (Other additives) Disperse polymer compounds in the liquid crystal phase,
A polymer compound may coexist in the organic semiconductor liquid crystal composition in order to allow the liquid crystal phase to exist in the polymer matrix. At this time, a polymerizable monomer may be added to the organic semiconductor liquid crystal composition to be polymerized when a liquid crystal cell (liquid crystal element) is produced, or a polymer compound may be added from the beginning. (Organic Semiconductor Compound) Examples of organic semiconductor compounds include “organic semiconductors” edited by Hiroo Iguchi, Ichiro Nakata and Masahiro Hino.
Kyoritsu Shuppan Co., Ltd. (1966), J. E. Katon
Written by Hidetoshi Tsuchida "Polymer Organic Semiconductor" Shokoido Co., Ltd. (1
972) and the Chemical Society of Japan, “π-Electron Organic Solids-Molecular Design, Electronic Properties (Charge and Spin), Application- (Quarterly Chemistry Review No. 35)”, Academic Publishing Center (199
8) or Junichi Hanna et al., "Journal of the Photographic Society of Japan", Vol. 63, No. 2, p.
69 (2000), a compound in which charge transfer occurs by intermolecular hopping conduction (π-electron cyclic compound, conjugated polymer compound having high rigidity) and a charge transfer complex-forming compound can be mentioned.

Examples of the compound in which charge transfer occurs by intermolecular hopping conduction include pipericin, pyrantrone,
Flavantron, quaterrylene, naphthalene, anthracene, tetracene, pentalone, p-terphenyl, p
-Quaterphenyl, 6-dimethylamino-2-
(4′-Nitrophenyl) benzothiazole, phenothiazine, 2,9-diethoxydioxazine, 3H-phenoxazin-3-one, 10-methyl-5H-benzo [a] phenixazin-5-one, 7-anilino- 14
H-naphtho [2,3-a] -phenothiazine-8,13
-Dione, dimethyl sexithiophene, 2- (4'-heptyloxyphenyl) -6-dodecylthiobenzothiazole, 2- (4'-octylphenyl) -6-dodecyloxynaphthalene and other π-electron cyclic compounds, polyphenylene, Examples thereof include conjugated polymer compounds such as polythienylene, polypyrrole, and polyphenylene vinylene.

Examples of the charge transfer complex forming compound include pyrene, dimethylaniline, p-phenylenediamine, tetramethyl-p-phenylenediamine, durendiamine, phenothiazine, tetrathiotetracene, tetraaminoanthraquinone and 1-tetrathiotetranyl. An electron-donating compound such as 4- (2-ethylhexyloxy) benzoate and 1,3,5-trinitrobenzene, 2,4,7-trinitrofluorenone, p-chloranil, 2,3-dichloro-5,6 -Dicyano-p-benzoquinone, tetracyanoethylene, tetracyano-p-
Tetrathiotetracene formed from a combination with an electron-accepting compound such as benzoquinodimethane, 4-oxocyclopentadithiophene-tetracyanoquinodimethane-
Tetracyanoethylene complex, pyrene-1,3,5-trinitrobenzene complex, durendiamine-p-chloranil complex and tetraaminoanthraquinone-tetracyano-
Examples thereof include p-benzoquinodimethane complex.

The amount added to these chiral nematic liquid crystal compositions may be within the range that does not disturb the liquid crystallinity thereof, but the solubility in the liquid crystal composition and the conductivity (the above semiconductor characteristics).
Determined by the balance of.

A nematic liquid crystal or a chiral dopant may also serve as these organic semiconductor compounds.

As shown in FIG. 1, the liquid crystal driving electrode 13,
A drive voltage applying device 3 capable of applying a drive voltage Vl to 14
0 is connected, and the charge extraction electrodes 15 and 16 are connected in series with a charge extraction voltage application device 40 and a display lamp 50 that can apply the charge extraction voltage Vs. The display lamp 50 can display a conduction state between the electrodes 15 and 16 when turned on and an insulation state between the electrodes 15 and 16 when turned off.

The driving voltage applying device 30 can apply a driving voltage Vl ₁ for changing the molecular arrangement of liquid crystals exhibiting a cholesteric phase to a planar arrangement and a driving voltage Vl ₂ (<Vl ₁ ) for changing the molecular arrangement to a focal conic arrangement. Further, in order to enable liquid crystal driving, it is desirable to make the charge extraction voltage Vs smaller than the drive voltage Vl. Here, the relationship between the drive voltage Vl and the charge extraction voltage Vs is Vl (Vl ₁ > Vl). ₂ )> Vs.

In the organic semiconductor liquid crystal device 1A shown in FIG.
When a driving voltage Vl ₁ is applied to the organic semiconductor liquid crystal composition LC, the molecular alignment of the liquid crystal exhibiting the cholesteric phase becomes a planar alignment (see FIG. 1A), and when the driving voltage Vl ₂ is applied, the liquid crystal exhibiting the cholesteric phase is formed. The molecular sequence becomes a focal conic sequence (see FIG. 1 (B)). And
The planar alignment state and the focal conic alignment state of the liquid crystal can be maintained even after the voltage is applied.

In this electrode structure, the liquid crystal driving electrode 13,
14 and the charge extraction electrodes 15 and 16 are parallel or substantially parallel to each other, and the charge extraction electrodes 15 and 16 are in contact with the organic semiconductor liquid crystal composition LC. And device 3
A driving voltage Vl ₁ or Vl ₂ is applied between 0 and the liquid crystal driving electrodes 13 and 14. Further, the charge extraction voltage Vs is applied from the device 40 between the charge extraction electrodes 15 and 16.

As shown in FIG. 1A, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the planar alignment, the helical axis B of the liquid crystal molecule a is aligned with the liquid crystal driving electrodes 13 and 14 in the planar alignment. To the vertical or nearly vertical,
It is also perpendicular or substantially perpendicular to the charge extraction electrodes 15 and 16 which are parallel or substantially parallel to the electrodes 13 and 14. An electrode 1 which is perpendicular or substantially perpendicular to the spiral axis B of the liquid crystal molecule a.
When a charge extraction voltage Vs is applied between the devices 5 and 16 from the device 40, an electric field can be applied in the optical axis direction X of the liquid crystal molecule alignment (direction of the spiral axis B of the liquid crystal molecules a). At this time, a current flows between the electrodes 15 and 16 in contact with the liquid crystal composition LC, and the lamp 50 is turned on.

On the other hand, as shown in FIG. 1B, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the helical axis B of the liquid crystal molecule a in the focal conic alignment has the liquid crystal driving electrode. It is parallel to or substantially parallel to the electrodes 13 and 14, and is also parallel to or approximately parallel to the charge extraction electrodes 15 and 16 that are parallel or substantially parallel to the electrodes 13 and 14. When the charge extraction voltage Vs is applied from the device 40 between the electrodes 15 and 16 parallel or substantially parallel to the spiral axis B of the liquid crystal molecule a, the optical axis direction of the liquid crystal molecule array (direction of the spiral axis B of the liquid crystal molecule a). An electric field can be applied in the direction Y orthogonal to X. At this time, the electrodes 15 and 16 that are in contact with the liquid crystal composition LC exhibit insulation, and the lamp 50 is turned off.

In the case of this flat type electrode structure, a semiconductor pattern having a memory property (a liquid crystal pattern exhibiting the semiconductor characteristics) can be formed in the electrode surface.

Further, the organic semiconductor liquid crystal element 1A shown in FIG.
Because the planar alignment of the liquid crystal molecules a exhibiting a cholesteric phase has the selective reflection ability of visible wavelength light, at least in the optical axis direction X of the liquid crystal molecule alignment (that is, the direction of the spiral axis B of the liquid crystal molecules a). Since a current flows when an electric field is applied, the semiconductor part (the part exhibiting the semiconductor characteristics) can be discriminated from the energized state as a colored part due to the selective reflectivity,
It can also be handled as an image display part.

When the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, conversion to the planar alignment may be performed by applying pressure to the organic semiconductor liquid crystal composition LC.

FIG. 2 shows the organic semiconductor liquid crystal device in which the stable state of the focal conic alignment of the liquid crystal molecules a exhibiting a cholesteric phase is converted into the planar alignment by applying pressure to the organic semiconductor liquid crystal composition LC. In addition, in the element of FIG. 2, the same reference numerals are attached to the portions having basically the same configuration and operation as those of the element of FIG.

The organic semiconductor liquid crystal device 1B shown in FIG. 2 includes a pair of substrates 11 and 12, and a pair of charge extractions for applying the charge extraction voltage Vs showing the semiconductor characteristics are provided on the substrates 11 and 12, respectively. Electrodes 15 and 16 are formed. The substrates 11 and 12 are arranged so that their electrode forming surfaces face each other, and the organic semiconductor liquid crystal composition LC is sandwiched between the substrates 11 and 12.

As shown in FIG. 2, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, when the pressure P is applied to the organic semiconductor liquid crystal composition LC, the helical axis B of the liquid crystal molecule a is The planar alignment of the liquid crystal molecules a is formed in the portion aligned with the pressure P direction X ′ and to which the pressure P is applied. As described above, the planar alignment of the liquid crystal molecules a is also formed by the pressure P applied to the organic semiconductor liquid crystal composition LC, and therefore the conductive portion has conductivity at least in the direction X ′ of the helical axis B of the liquid crystal molecules a. Indicates.

FIG. 3 is a cross-sectional view showing a schematic structure of another example of the organic semiconductor liquid crystal element, and FIG. 3 (A) changes the molecular arrangement of the liquid crystal exhibiting the cholesteric phase to the planar arrangement (or focal conic arrangement). Drive voltage Vl ₁ (or V
l ₂ ) is a diagram showing a planar alignment state (or focal conic alignment state) when a first (or second) liquid crystal driving electrode is applied, and FIG. 3B is a liquid crystal molecule showing a cholesteric phase. Drive voltage Vl ₁ (or Vl) for changing the array to a planar array (or focal conic array)
It is a figure which shows the planar arrangement state (or focal conic arrangement state) when ₂ ) is applied between the 2nd (or 1st) liquid crystal drive electrodes. In addition, in the element of FIG.
The elements having basically the same configuration and function as those of the element are given the same reference numerals.

In the organic semiconductor liquid crystal element 2A shown in FIG. 3, the organic semiconductor liquid crystal composition LC is sandwiched between at least a pair of electrodes (here, the first conductive electrodes 15a and 16a and the second conductive electrodes 15b and 16b). Therefore, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the planar alignment or the focal conic alignment, a conductive electric field is applied at least in the optical axis direction (direction of the spiral axis B of the liquid crystal molecule a) X of the liquid crystal molecule alignment. As a result, a current flows, and at least the semiconductor characteristics exhibit an insulating property in the direction Y orthogonal to the optical axis direction (direction of the spiral axis B of the liquid crystal molecules a) X of the liquid crystal molecule alignment.

The organic semiconductor liquid crystal element 2A has a three-dimensional electrode structure and includes a pair of first substrates 11a and 12a and a pair of second substrates 11b and 12b.

On the substrates 11a and 12a, a pair of first liquid crystal driving electrodes 13 for applying a driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase, respectively.
a and 14a are formed. On the electrodes 13a and 14a, a pair of first charge extraction (conduction) electrodes 15a and 16a for applying the charge extraction voltage Vs exhibiting the semiconductor characteristics are formed via the insulating layer 17, respectively.

Further, on the substrates 11b and 12b, a pair of second liquid crystal driving electrodes 13b and 14b for applying a driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase are formed. Electrodes 13b, 14b
A pair of second charge extraction (conductivity) electrodes 15b and 16b for applying the charge extraction voltage Vs exhibiting the above-mentioned semiconductor characteristics are formed on the upper part of the electrodes 15b and 16b, respectively.

The substrates 11a, 12a and the substrate 11
Electrodes forming surfaces of both b and 12b are arranged to face each other, and the organic semiconductor liquid crystal composition LC is sandwiched between the substrates 11a and 12a and the substrates 11b and 12b. The substrates 11a, 12a and the substrates 11b, 12b are arranged in a direction perpendicular to or substantially perpendicular to each other, and are supported by a pillar member 18 made of an insulating material at a portion where the substrates intersect.

The liquid crystal exhibiting the cholesteric phase is a liquid crystal forming the cholesteric phase, and the arrangement state of the helical axis B of the liquid crystal molecule a is changed by the application of an electric field or pressure. In this case, driving for changing the molecular arrangement of the liquid crystal is performed. Electrodes 13a, 14a (or electrodes 13b, 14) to which voltage Vl is applied
b) is parallel or substantially parallel to the molecular arrangement of the planar arrangement in which the spiral axis B is perpendicular to or substantially perpendicular to the pair of first substrates 11a and 12a (or the pair of second substrates 11b and 12b) formed with b). Is a liquid crystal showing the molecular arrangement of the focal conic arrangement.

A first drive voltage applying device 30a capable of applying a drive voltage Vl is connected to the liquid crystal drive electrodes 13a and 14a, and a first charge capable of applying a charge extraction voltage Vs to the charge extraction electrodes 15a and 16a. The extraction voltage applying device 40a and the first display lamp 50a are connected in series. When the display lamp 50a is turned on, the electrode 15a,
The conduction state between the electrodes 16a can be displayed, and the insulation state between the electrodes 15a and 16a can be displayed when the light is turned off.

A second drive voltage applying device 30b capable of applying a drive voltage Vl to the liquid crystal drive electrodes 13b and 14b.
Are connected, and the charge extraction electrodes 15b and 16b
A second charge extraction voltage applying device 40b capable of applying the charge extraction voltage Vs and a second display lamp 50b are connected in series to the. When the indicator lamp 50b is turned on, the electrode 1
The conduction state between 5b and 16b is set to the electrodes 15b and 1 when the light is turned off.
The insulation state between 6b can be displayed.

In each of the drive voltage applying devices 30a and 30b, the drive voltage Vl ₁ for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase to the planar arrangement and the drive voltage Vl ₂ for changing the focal conic arrangement (<Vl ₁ )
Can be applied. Here, the relationship between the drive voltage Vl and the charge extraction voltage Vs is Vl (Vl ₁ > Vl ₂ )> Vs.

In the organic semiconductor liquid crystal element 2A shown in FIG. 3,
When the driving voltage Vl ₁ is applied to the organic semiconductor liquid crystal composition LC, the molecular alignment of the liquid crystal exhibiting the cholesteric phase becomes the planar alignment, and when the driving voltage Vl ₂ is applied, the molecular alignment of the liquid crystal exhibiting the cholesteric phase becomes the focal conic alignment. . The planar alignment state and the focal conic alignment state of the liquid crystal can be maintained even after the voltage is applied.

In this electrode structure, the liquid crystal driving electrode 13
a, 14a and charge extraction electrodes 15a, 16a are parallel or substantially parallel to each other, and liquid crystal driving electrodes 13b, 1
4b and the charge extraction electrodes 15b and 16b are parallel or substantially parallel to each other. Charge extraction electrodes 15a, 16
a and 15b and 16b are perpendicular to each other or substantially perpendicular to each other,
Both are in contact with the organic semiconductor liquid crystal composition LC. Then, between the device 30a and the liquid crystal driving electrodes 13a and 14a, or from the device 30b to the liquid crystal driving electrodes 13b and 14b.
The drive voltage Vl ₁ or Vl ₂ is applied between them. Also,
Between the device 40a and the charge extraction electrodes 15a and 16a, or from the device 40b, the charge extraction electrodes 15b and 1a.
The charge extraction voltage Vs is applied between 6b.

As shown in FIG. 3A (or FIG. 3B), the drive voltage Vl (Vl) is applied from the device 30a (or 30b).
₁ ) is a liquid crystal driving electrode 13a, 14a (or 13b, 1
4b), when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the planar alignment, the helical axis B of the liquid crystal molecule a in the planar alignment causes the liquid crystal driving electrodes 13a and 14a (or 13b and 14b). ) To the electrodes 13a, 14a (or 1)
3b, 14b) is also vertical or substantially vertical to the charge extraction electrodes 15a, 16a (or 15b, 16b) which are parallel or substantially parallel to 3b, 14b). Electrodes 15a, 16a (or 15b, which are perpendicular or substantially perpendicular to the spiral axis B of the liquid crystal molecule a)
When a charge extraction voltage Vs is applied from the device 40a (or 40b) during 16b), an electric field can be applied in the optical axis direction X of the liquid crystal molecule alignment (direction of the spiral axis B of the liquid crystal molecule a). At this time, a current flows between the electrodes 15a and 16a (or 15b and 16b) in contact with the liquid crystal composition LC, and the lamp 50a (or 50b) is turned on.

On the other hand, the helical axis B of the liquid crystal molecule a is parallel or substantially parallel to the liquid crystal driving electrodes 13b and 14b (or 13a and 14a), and the electrodes 13b and 14b (or 13).
a, 14a) is also parallel or substantially parallel to the charge extraction electrodes 15b, 16b (or 15a, 16a) which are parallel or substantially parallel. The electrodes 15b, 16b (or 15a, 1) that are parallel or substantially parallel to the spiral axis B of the liquid crystal molecule a.
When a charge extraction voltage Vs is applied from the device 40b (or 40a) during 6a), an electric field can be applied in a direction Y orthogonal to the optical axis direction (direction of the spiral axis B of the liquid crystal molecules a) X of the liquid crystal molecule alignment. it can. At this time, the electrodes 15b and 16b (or 15a and 16a) that are in contact with the liquid crystal composition LC
In the meantime, insulation is exhibited, and the lamp 50b (or 50a) is turned off.

In the three-dimensional electrode configuration of FIG. 3, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the orientation of the liquid crystal molecule a is such that the helical axis B of the liquid crystal molecule a is the charge extraction. Electrode 15b,
16b (or 15a, 16a) is oriented vertically or substantially vertically (FIG. 3 (B) (or FIG. 3 (A)).
reference).

In the alignment of the liquid crystal molecules a, the alignment shown in FIG.
(Or FIG. 3 (A)), the device 30a (or 3
0b) to drive voltage Vl (Vl ₂ ) from liquid crystal driving electrode 1
When the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment by applying the voltage between 3a and 14a (or 13b and 14b), the helical axis B of the liquid crystal molecule a is used for driving the liquid crystal in the focal conic alignment. It is parallel or substantially parallel to the electrodes 13a, 14a (or 13b, 14b), but as described above, it is vertical or substantially perpendicular to the charge extraction electrodes 15b, 16b (or 15a, 16a). . Electrodes 15b and 16b (or 15a, which are perpendicular or substantially perpendicular to the spiral axis B of the liquid crystal molecule a)
When a charge extraction voltage Vs is applied from the device 40b (or 40a) during 16a), an electric field can be applied in the optical axis direction X of the liquid crystal molecule alignment (direction of the spiral axis B of the liquid crystal molecule a). At this time, a current flows between the electrodes 15b and 16b (or 15a and 16a) in contact with the liquid crystal composition LC, and the lamp 50b (or 50a) is turned on.

On the other hand, the spiral axis B of the liquid crystal molecule a is parallel or substantially parallel to the liquid crystal driving electrodes 13a and 14a (or 13b and 14b), and the electrodes 13a and 14a (or 13).
b, 14b) is also parallel or substantially parallel to the charge extraction electrodes 15a, 16a (or 15b, 16b) which are also parallel or substantially parallel. Electrodes 15a, 16a (or 15b, 1 which are parallel or substantially parallel to the spiral axis B of the liquid crystal molecule a)
When a charge extraction voltage Vs is applied from the device 40a (or 40b) during 6b), an electric field can be applied in the direction Y orthogonal to the optical axis direction (direction of the spiral axis B of the liquid crystal molecules a) X of the liquid crystal molecule alignment. it can. At this time, the electrodes 15a and 16a (or 15b and 16b) that are in contact with the liquid crystal composition LC
In the meantime, the insulating property is exhibited, and the lamp 50a (or 50b) is turned off.

FIG. 4 is a sectional view showing the schematic constitution of still another example of the organic semiconductor liquid crystal element, and FIG. 4 (A) is applied with a drive voltage for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase into the planar arrangement. FIG. 4B is a diagram showing the planar alignment state at this time, and FIG. 4B is a diagram showing the focal conic alignment state when a drive voltage for changing the molecular alignment of the liquid crystal exhibiting the cholesteric phase to the focal conic alignment is applied. In addition, in the element of FIG. 4, the same reference numerals are given to portions having basically the same configurations and operations as those of the elements of FIGS. 1 and 3. The element shown in FIG. 4 will be described below focusing on the points different from the element of FIG.

In the organic semiconductor liquid crystal element 2B shown in FIG. 4, the organic semiconductor liquid crystal composition LC is sandwiched between at least a pair of electrodes (here, the first conductive electrodes 15a and 16a and the second conductive electrodes 15b and 16b). Therefore, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the planar alignment or the focal conic alignment, a conductive electric field is applied at least in the optical axis direction (direction of the spiral axis B of the liquid crystal molecule a) X of the liquid crystal molecule alignment. As a result, a current flows, and at least the semiconductor characteristics exhibit an insulating property in the direction Y orthogonal to the optical axis direction (direction of the spiral axis B of the liquid crystal molecules a) X of the liquid crystal molecule alignment.

The organic semiconductor liquid crystal element 2B has a three-dimensional electrode structure and includes a pair of first substrates 11a and 12a and a pair of second substrates 11b and 12b.

On the substrates 11a and 12a, a pair of liquid crystal driving electrodes 13 and 14 for applying a driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase, respectively.
Are formed. A pair of first charge extraction (conducting) electrodes 15a, 16a for applying the charge extraction voltage Vs exhibiting the semiconductor characteristics are formed on the electrodes 13, 14 via an insulating layer 17, respectively.

On the substrates 11b and 12b, a pair of second charge extracting (conducting) electrodes 15b and 16 for applying the charge extracting voltage Vs exhibiting the semiconductor characteristics, respectively.
b is formed.

The liquid crystal exhibiting a cholesteric phase is a liquid crystal forming a cholesteric phase, and the arrangement state of the helical axis B of the liquid crystal molecule a is changed by the application of an electric field or pressure. In this case, the driving for changing the molecular arrangement of the liquid crystal. A pair of first substrates 1 on which electrodes 13 and 14 to which voltage Vl is applied are formed.
It is a liquid crystal showing a molecular arrangement of a planar arrangement in which the spiral axis B is perpendicular to or substantially perpendicular to 1a and 12a and a molecular arrangement of a focal conic arrangement in which the spiral axis B is parallel to or substantially parallel to.

A driving voltage V is applied to the liquid crystal driving electrodes 13 and 14.
A drive voltage applying device 30 capable of applying 1 is connected.

In this electrode structure, the liquid crystal driving electrode 13,
14 and the charge extraction electrodes 15a and 16a are parallel or substantially parallel to each other. Charge extraction electrodes 15a, 16
a and 15b and 16b are perpendicular to each other or substantially perpendicular to each other,
Both are in contact with the organic semiconductor liquid crystal composition LC. Then, the drive voltage Vl ₁ for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase to the planar arrangement or the drive voltage Vl ₂ for changing to the focal conic arrangement is applied between the device 30 and the liquid crystal driving electrodes 13 and 14. Further, between the device 40a and the charge extracting electrodes 15a and 16a,
Alternatively, the charge extraction electrodes 15b and 16b from the device 40b
The charge extraction voltage Vs is applied between them.

As shown in FIG. 4 (A), when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the planar alignment, the helical axis B of the liquid crystal molecule a is aligned with the liquid crystal driving electrodes 13 and 14 in the planar alignment. To the vertical or nearly vertical,
It is also perpendicular or substantially perpendicular to the charge extraction electrodes 15a, 16a which are parallel or substantially parallel to the electrodes 13, 14. When a charge extraction voltage Vs is applied from the device 40a between the electrodes 15a and 16a perpendicular to or substantially perpendicular to the spiral axis B of the liquid crystal molecule a, the optical axis direction of the liquid crystal molecule array (direction of the spiral axis B of the liquid crystal molecule a). An electric field can be applied to X. At this time, the electrode 15 in contact with the liquid crystal composition LC
A current flows between a and 16a, and the lamp 50a lights up.

On the other hand, the spiral axis B of the liquid crystal molecule a is parallel or substantially parallel to the charge extracting electrodes 15b and 16b. When a charge extraction voltage Vs is applied from the device 40b between the electrodes 15b and 16b parallel or substantially parallel to the spiral axis B of the liquid crystal molecule a, the optical axis direction of the liquid crystal molecule array (direction of the spiral axis B of the liquid crystal molecule a). An electric field can be applied in the direction Y orthogonal to X. At this time, the electrodes 15b and 16b in contact with the liquid crystal composition LC exhibit an insulating property, and the lamp 50b is turned off.

In this three-dimensional electrode structure, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the orientation of the liquid crystal molecule a is such that the spiral axis B of the liquid crystal molecule a is for charge extraction. Electrode 15b,
The orientation is such that it is perpendicular or substantially perpendicular to 16b.

In the orientation of the liquid crystal molecules, as shown in FIG. 4B, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the helical axis B of the liquid crystal molecule a is in the focal conic alignment. Is parallel to or substantially parallel to the liquid crystal driving electrodes 13 and 14, but is vertical to substantially vertical to the charge extraction electrodes 15b and 16b as described above. When the charge extraction voltage Vs is applied from the device 40b between the electrodes 15b and 16b which are perpendicular or substantially perpendicular to the spiral axis B of the liquid crystal molecule a, the optical axis direction of the liquid crystal molecule array (direction of the spiral axis B of the liquid crystal molecule a). An electric field can be applied to X. At this time, the liquid crystal composition L
A current flows between the electrodes 15b and 16b which are in contact with C,
The lamp 50b lights up.

On the other hand, the spiral axis B of the liquid crystal molecule a is parallel to or substantially parallel to the liquid crystal driving electrodes 13 and 14, and to the charge extraction electrodes 15a and 16a parallel or substantially parallel to the electrodes 13 and 14. They are also parallel or substantially parallel to each other. An electrode 15 which is parallel or substantially parallel to the spiral axis B of the liquid crystal molecule a.
When a charge extraction voltage Vs is applied from the device 40a between a and 16a, an electric field can be applied in a direction Y orthogonal to the optical axis direction (direction of the spiral axis B of the liquid crystal molecules a) X of the liquid crystal molecule alignment. At this time, the electrodes 15a and 16a in contact with the liquid crystal composition LC exhibit insulating properties, and the lamp 50a is turned off.

FIG. 5 is a sectional view showing the schematic constitution of still another example of the organic semiconductor liquid crystal element, and FIG. 5 (A) is applied with a drive voltage for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase into the planar arrangement. FIG. 5B is a diagram showing the planar alignment state at this time, and FIG. 5B is a diagram showing the focal conic alignment state when a drive voltage for changing the molecular alignment of the liquid crystal exhibiting the cholesteric phase to the focal conic alignment is applied. In addition, in the element of FIG. 5, the same reference numerals are given to portions having basically the same configuration and operation as those of the elements of FIGS. 1, 3 and 4. The element shown in FIG. 5 will be described below focusing on the points different from the elements of FIGS. 3 and 4.

In the organic semiconductor liquid crystal element 2C shown in FIG. 5, the organic semiconductor liquid crystal composition LC has at least a pair of electrodes (here, liquid crystal driving electrodes 13 and 14 and conductive electrodes 15 and 1).
6) When sandwiched between the liquid crystal molecules and exhibiting a cholesteric phase in a stable molecular state of planar alignment or focal conic alignment, at least the optical axis direction of the liquid crystal molecule alignment (direction of the helical axis B of the liquid crystal molecule a) A current flows when an electric field is applied to X, and at least has a semiconductor property of insulating properties in a direction Y orthogonal to the optical axis direction of liquid crystal molecule alignment (direction of spiral axis B of liquid crystal molecules a) X. .

The organic semiconductor liquid crystal element 2C has a three-dimensional electrode structure and includes a pair of first substrates 11a and 12a and a pair of second substrates 11b and 12b.

On the substrates 11a and 12a, a pair of liquid crystal driving electrodes 13 and 14 for applying a driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase, respectively.
Are formed.

On the substrates 11b and 12b, a pair of charge extracting (conducting) electrodes 15 and 16 for applying the charge extracting voltage Vs exhibiting the semiconductor characteristics are formed.

A charge extraction voltage applying device 40 and a display lamp 50, which can apply a charge extraction voltage Vs, are connected in series to the charge extraction electrodes 15 and 16. The indicator lamp 50 indicates the conduction state between the electrodes 15 and 16 at the time of lighting.
When turned off, the insulation state between the electrodes 15 and 16 can be displayed.

In this electrode structure, the liquid crystal driving electrode 13,
14 and the charge extraction electrodes 15 and 16 are perpendicular to or substantially perpendicular to each other, and the charge extraction electrodes 15 and 16 are in contact with the organic semiconductor liquid crystal composition LC. And device 3
A driving voltage Vl ₁ for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase to the planar arrangement or a driving voltage Vl ₂ for changing the focal arrangement to the focal conic arrangement is applied between 0 and the liquid crystal driving electrodes 13 and 14. In addition, the charge extraction voltage Vs is applied between the device 40 and the charge extraction electrodes 15 and 16.
Is applied.

In this three-dimensional electrode structure, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the orientation of the liquid crystal molecule a is such that the helical axis B of the liquid crystal molecule a is for charge extraction. Electrodes 15, 1
The orientation is perpendicular to or substantially perpendicular to 6.

In such alignment of the liquid crystal molecules, as shown in FIG. 5A, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the helical axis B of the liquid crystal molecule a is in the focal conic alignment. Is parallel to or substantially parallel to the liquid crystal driving electrodes 13 and 14, but is vertical to substantially vertical to the charge extraction electrodes 15 and 16 as described above. When a charge extraction voltage Vs is applied from the device 40 between the electrodes 15 and 16 which are perpendicular or substantially perpendicular to the spiral axis B of the liquid crystal molecule a, the optical axis direction of the liquid crystal molecule array (direction of the spiral axis B of the liquid crystal molecule a). An electric field can be applied to X. At this time, a current flows between the electrodes 15 and 16 in contact with the liquid crystal composition LC, and the lamp 50 is turned on.

On the other hand, as shown in FIG. 5B, when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the planar alignment, the helical axis B of the liquid crystal molecules a is in the planar alignment.
Is perpendicular to or substantially perpendicular to the liquid crystal driving electrodes 13 and 14, and parallel to or substantially parallel to the charge extraction electrodes 15 and 16 which are perpendicular to or substantially perpendicular to the electrodes 13 and 14. The charge extraction voltage Vs from the device 40 is applied between the electrodes 15 and 16 parallel or substantially parallel to the spiral axis B of the liquid crystal molecule a.
When is applied, the electric field can be applied in the direction Y orthogonal to the optical axis direction (direction of the spiral axis B of the liquid crystal molecules a) X of the liquid crystal molecule alignment. At this time, the electrodes 15 and 16 that are in contact with the liquid crystal composition LC exhibit insulation, and the lamp 50 is turned off.

Organic semiconductor liquid crystal element 2 shown in FIGS. 3 to 5.
According to A to 2C, the organic semiconductor liquid crystal device 1A shown in FIG.
Has the same advantages as.

In the case of the three-dimensional electrode structure shown in FIGS. 3 and 4, the organic semiconductor liquid crystal elements 2A and 2B can be made anisotropic in conductivity.

Specific examples of the organic semiconductor liquid crystal composition according to the present invention will be described below.

The following were used as the chiral nematic liquid crystal composition. That is, as the chiral nematic liquid crystal composition A, a nematic liquid crystal (80 parts by weight), a chiral material R1011 (manufactured by Merck) (4.0 parts by weight) and a chiral material R811 (manufactured by Merck) (16.0 parts by weight) were used.
Was used.

As the chiral nematic liquid crystal composition B,
Chiral material R101 for nematic liquid crystal (90 parts by weight)
1 (Merck) (2.0 parts by weight) and chiral material R
811 (manufactured by Merck & Co., Inc.) (8.0 parts by weight) was used.

The following organic semiconductor compounds were used. That is, 2- (4'-octylphenyl) is a compound in which charge transfer occurs by intermolecular hopping conduction.
-6-dodecyloxynaphthalene or dimethyl sexithiophene was used.

As a compound which forms a charge transfer complex, 1-tetrathiotetranyl-4- which is an electron-donating compound is used.
(2-Ethylhexyloxy) benzoate and 4-oxocyclopentadithiophene-tetracyanoquinodimethane, which is an electron-accepting compound, were used. -Organic semiconductor liquid crystal composition 1 By adding 2- (4'-octylphenyl) -6-dodecyloxynaphthalene (30 parts by weight) to the chiral nematic liquid crystal composition A (70 parts by weight),
An organic semiconductor liquid crystal composition 1 was obtained. Organic Semiconductor Liquid Crystal Composition 2 Organic semiconductor liquid crystal composition 2 was obtained by adding dimethyl sexithiophene (20 parts by weight) to chiral nematic liquid crystal composition B (80 parts by weight). -Organic semiconductor liquid crystal composition 3 Chiral nematic liquid crystal composition B (60.5
1-tetrathiotetranyl-4- (2-ethylhexyloxy) benzoate (29.5 parts by weight) and 4-oxocyclopentadithiophene-tetracyanoquinodimethane (10 parts by weight). Thereby, the organic semiconductor liquid crystal composition 3 was obtained.

[0109]

As described above, according to the present invention, it is possible to provide an organic semiconductor liquid crystal composition that makes the best use of the characteristics of the memory properties of liquid crystals exhibiting a cholesteric phase, the molecular alignment state and the electric field response thereof.

Further, according to the present invention, it is possible to provide an organic semiconductor liquid crystal element which makes the best use of the characteristics of the memory property of liquid crystal exhibiting a cholesteric phase, the state of molecular alignment and the electric field response thereof.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of an example of an organic semiconductor liquid crystal device, and FIG. 1 (A) shows a planar alignment state when a drive voltage for changing a molecular alignment of liquid crystal exhibiting a cholesteric phase into a planar alignment is applied. FIG. 6B is a diagram showing a state of focal conic alignment when a drive voltage for changing the molecular alignment of liquid crystal exhibiting a cholesteric phase into a focal conic alignment is applied.

FIG. 2 is a diagram showing a state in which a stable state of a focal conic alignment of liquid crystal molecules exhibiting a cholesteric phase is converted into a planar alignment by applying pressure to an organic semiconductor liquid crystal composition in an organic semiconductor liquid crystal device.

FIG. 3 is a cross-sectional view showing a schematic configuration of another example of the organic semiconductor liquid crystal element, and FIG. 3A is a driving voltage Vl for changing the molecular alignment of liquid crystal exhibiting a cholesteric phase to a planar alignment (or focal conic alignment). ₁ (or Vl ₂ ) as the first
(Or 2) It is a diagram showing a planar alignment state (or a focal conic alignment state) when applied between the liquid crystal driving electrodes, and FIG. 6B shows a molecular alignment of the liquid crystal exhibiting a cholesteric phase as the planar alignment (or the focal alignment). Conic array)
FIG. 9 is a diagram showing a planar alignment state (or focal conic alignment state) when a drive voltage Vl ₁ (or Vl ₂ ) that is changed to a value is applied between the second (or first) liquid crystal drive electrodes.

FIG. 4 is a cross-sectional view showing a schematic configuration of still another example of the organic semiconductor liquid crystal element, and FIG. 4A is a planer when a drive voltage for changing the molecular arrangement of the liquid crystal exhibiting a cholesteric phase into a planar arrangement is applied. FIG. 6B is a diagram showing an arrangement state, and FIG. 6B is a diagram showing a focal conic arrangement state when a drive voltage for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase to the focal conic arrangement is applied.

FIG. 5 is a cross-sectional view showing a schematic configuration of still another example of the organic semiconductor liquid crystal element, and FIG. 5A is a planer when a drive voltage for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase into the planar arrangement is applied. FIG. 6B is a diagram showing an arrangement state, and FIG. 6B is a diagram showing a focal conic arrangement state when a drive voltage for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase to the focal conic arrangement is applied.

FIG. 6 shows that when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the phase stable state of the planar alignment or the focal conic alignment, an electric field is applied at least in the optical axis direction of the liquid crystal molecular alignment, in other words, in the direction of the spiral axis of the liquid crystal molecules. By doing so, an electric current flows, and it is a diagram for explaining a semiconductor characteristic that exhibits an insulating property at least in the direction orthogonal to the optical axis direction of the liquid crystal molecule array, in other words, in the direction orthogonal to the direction of the helical axis of the liquid crystal molecules. .

[Explanation of symbols]

1A, 1B Organic semiconductor liquid crystal elements 2A, 2B, 2C Organic semiconductor liquid crystal elements 11, 12 A pair of substrates 11a, 12a A pair of first substrates 11b, 12b A pair of second substrates 13, 14 A pair of liquid crystal driving electrodes 13a, 14a A pair of first liquid crystal driving electrodes 13b and 14b A pair of second liquid crystal driving electrodes 15 and 16 A pair of charge extraction electrodes 15a and 16a A pair of first charge extraction electrodes 15b and 16b A pair of second charge extraction electrodes 17 Insulating Layer 18 Strut Member Made of Insulating Material 30 Drive Voltage Applying Device 30a First Drive Voltage Applying Device 30b Second Drive Voltage Applying Device 40 Charge Extracting Voltage Applying Device 40a First Charge Extracting Voltage Applying Device 40b Second Charge Extracting Voltage Applying Device 50 Display lamp 50a First display lamp 50b Second display lamp a Liquid crystal molecule A Layer B of liquid crystal molecule a Helical axis LC of liquid crystal molecule a Organic semiconductor liquid crystal composition P Pressure Vl (Vl ₁ > Vl ₂ ) Drive voltage Vs Charge extraction voltage X Direction of helical axis B of liquid crystal molecule a X ′ Direction of pressure P Y orthogonal to X direction direction

Claims (5)

[Claims] 1. An organic semiconductor liquid crystal composition comprising a liquid crystal exhibiting a cholesteric phase and an organic semiconductor compound. 2. The organic semiconductor liquid crystal composition according to claim 1, wherein the organic semiconductor compound is a charge transfer complex-forming compound or a compound in which charge transfer occurs by intermolecular hopping conduction. 3. The organic semiconductor liquid crystal composition according to claim 1 or 2 is sandwiched between at least a pair of electrodes, and the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in a stable state of planar alignment or focal conic alignment. At this time, an electric current flows by applying an electric field at least in the direction of the optical axis of the liquid crystal molecule array, and the organic semiconductor has a semiconductor property of exhibiting insulation at least in the direction orthogonal to the optical axis direction of the liquid crystal molecule array. Liquid crystal element. 4. The organic semiconductor liquid crystal element according to claim 3, wherein a relationship between a driving voltage Vl for changing the molecular arrangement of the liquid crystal exhibiting the cholesteric phase and a conduction voltage Vs exhibiting the semiconductor characteristics is Vl> Vs. 5. The organic compound according to claim 3, wherein when the molecular alignment of the liquid crystal exhibiting the cholesteric phase is in the stable state of the focal conic alignment, the conversion into the planar alignment is performed by applying a pressure to the organic semiconductor liquid crystal composition. Semiconductor liquid crystal device.