JP2001051275A - Liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely control alignment of liquid crystal molecules by three-dimensionally controlling the alignment of liquid crystal molecules in three or more directions. SOLUTION: A cell filled with a ferroelectric liquid crystal is provided with upper and lower alignment films 1, 2, front and back alignment films 3, 4, and left and right alignment films 5, 6 to three-dimensionally control the alignment of the liquid crystal molecules. Specifically, the upper and lower alignment films 1, 2 are composed of polyvinylalcohol alignment films, the front and back alignment films 3, 4 are composed of non-fluorine-based alignment films, and the left and right alignment films 5, 6 are composed of fluorine-based alignment films. With such a constitution, a ferroelectric liquid crystal molecules 7 have good wettability with the front and back alignment films 3, 4 but have low wettability with the left and right alignment films 5, 6 so that the molecules are aligned horizontally with the major axis of the liquid crystal molecule directs along the front and back alignment films 3, 4. In this method, the ferroelectric liquid crystal molecules 7 are aligned and controlled in the four directions of front, back, left and right, and its stable state is uniquely determined and turns into a monostable state. Therefore, voltages are applied stepwise in a stepwise pulse waveform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device and, more particularly, to an improvement in alignment control of liquid crystal molecules.

[0002]

2. Description of the Related Art In recent years, demands for electronic display devices have been increasing as man-machine interfaces.

[0003] Conventional electronic display devices include:
Self-luminous type and light-receiving type are classified, and as a self-luminous type electronic display device, CRT (cathode ray
tube, a plasma display (PDP), an electroluminescence display (ELD), a fluorescent display tube (VFD), a light emitting diode (LED), and the like.

As a light receiving type electronic display device, a liquid crystal display (LCD), an electrochromic display (ECD), an electrophoretic display (ECD)
PID), a dispersed particle oriented display (SPD), a colored particle rotating display (TBD), and the like are known.

[0005] LCDs using liquid crystals for displays have the characteristics of low power consumption, thinness and light weight, and are being applied to watches, calculators, computer monitors, and television receivers taking advantage of this. .

In such LCDs, typical types of liquid crystals include nematic liquid crystals having regularity in one axis direction and smectic liquid crystals having regularity in two axis directions.

As the former using a nematic liquid crystal, there are a TFT-TN LCD (thin film transistor twisted nematic liquid crystal display) which performs active driving using a thin film transistor, and a TFT-VA.
LCDs (thin film transistor vertical alignment liquid crystal displays), STN LCDs (super twisted nematic liquid crystal displays) that perform passive driving, and the like are common.

[0008] The latter using smectic liquid crystal include FLCD (ferroelectric display), AFLC
D (antiferroelectric liquid crystal display).

[0009]

SUMMARY OF THE INVENTION TFT-VA LCD
Is to make the dielectric anisotropy of liquid crystal molecules negative (the dielectric constant in the minor axis direction is larger than that in the major axis direction), orient the liquid crystal molecules homeotropically, and by the applied electric field, the transmittance by the inclination angle. Is the driving principle.

Therefore, since the molecular arrangement does not have a twisted structure as in TN LCD and is of a normally black type, the quality of black is excellent and the contrast ratio is excellent. Further, since the anchoring energy of the orientation control is low due to the element structure, the restriction from the interface is small, and relatively fast response can be achieved among the nematic liquid crystal (TN LCD).
2 to 3 times). Since the alignment regulating force can be determined by the interface interaction between the liquid crystal and the alignment film, a process such as rubbing is not required in principle.

However, it is difficult to completely control the direction in which the liquid crystal molecules are inclined with respect to the applied electric field, and it has been known that inverting domains are generated in a normal alignment film for vertical alignment, thereby lowering the contrast ratio. .

In order to improve this drawback, the angle between the long axis of the liquid crystal molecules and the plane of the alignment film has been conventionally adjusted by rubbing the alignment film for vertical alignment or tilting the electrode surface of each pixel.
A method has been proposed in which the liquid crystal molecules are arranged at an angle of less than 0 degrees, that is, inclining the liquid crystal molecules in advance even if the quality of black is sacrificed, but it is not sufficient.

On the other hand, FLC which is a smectic liquid crystal is
Research and development for CDs has been actively pursued to date. Ferroelectric liquid crystals were first synthesized by Meyer in 1975, and in 1980, Clark and Lagawar invented a surface-stabilized ferroelectric liquid crystal capable of domain inversion by an electric field.

The FLC itself has a permanent dipole moment in the minor axis direction and has spontaneous polarization, and therefore can respond directly to an electric field. It is about 1000 times faster than a nematic liquid crystal that responds by permittivity.

In addition, there is basically no twisted structure in the molecular arrangement, and the viewing angle dependence is small. Further, it has an excellent characteristic that it has a memory function of retaining an image even when the power is turned off, and that a simple matrix drive can be performed for 1000 or more scanning lines.

In the FLC element, the molecule switches between two states, state 1 and state 2, in response to an externally applied electric field E. This change in molecular orientation controls the transmittance by arranging liquid crystal molecules between orthogonal polarizers, causing a sharp change in the transmittance at a threshold voltage Vth with respect to the applied electric field. is there.

As described above, since the FLC display using the bistable mode is stable only in two states, it is difficult to perform gradation display by voltage control as in the TN mode. An area gray scale method for displaying a gray scale and a time division gray scale method for displaying a gray scale by digitally combining binary values within one field time have been proposed.

However, these methods have a problem that the gradation display becomes insufficient and the cost is increased.

The present invention has been proposed in view of such a conventional situation, and an object of the present invention is to provide a novel alignment control method capable of reliably controlling the alignment of liquid crystal molecules. It is an object to provide a liquid crystal element having characteristics.

[0020]

In order to achieve the above-mentioned object, the present invention provides a liquid crystal device in which liquid crystal is arranged in a cell, in which alignment of liquid crystal molecules is controlled three-dimensionally from three or more directions. It is characterized by being performed.

The alignment can be controlled by, for example, combining two or more types of alignment films having different interfacial mutual energies. Specifically, the contact angle of the alignment film with respect to the liquid crystal molecule long axis in the direction of the long axis of the liquid crystal molecule is determined. The contact angle of the alignment film in the minor axis direction of the liquid crystal molecule to the long axis of the liquid crystal molecule is less than 45 °.
The angle may be 5 ° or more.

In an ordinary liquid crystal element, liquid crystal is usually arranged in a gap between two substrates having an alignment film formed on an electrode.

In the alignment control method proposed from the three or more planes proposed in the present invention, for example, in a VA mode of a nematic liquid crystal, a rubbing step is not required, and the tilt direction of each liquid crystal molecule is determined without changing the distance between electrodes. it can.

In the FLC mode of the smectic liquid crystal, it is possible to align liquid crystal molecules in a desired direction by combining alignment films having different anchoring energies.

Further, the alignment method of the present invention determines the stable state of the ferroelectric liquid crystal as one, and is therefore very useful from the viewpoint of providing natural gradation.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a liquid crystal device to which the present invention is applied will be described in detail with reference to the drawings.

FIG. 1 shows the configuration of an alignment film for aligning a ferroelectric liquid crystal (smectic liquid crystal).

In this example, alignment films are arranged on the upper, lower, front, rear, left and right surfaces of a cell filled with ferroelectric liquid crystal, so that alignment of liquid crystal molecules is three-dimensionally controlled.

Specifically, the upper and lower alignment films 1 and 2 are polyvinyl alcohol alignment films. The front and rear alignment films 3 and 4 are non-fluorine alignment films. The left and right alignment films 5 and 6 are fluorine-based alignment films.

With such an alignment film configuration, the ferroelectric liquid crystal molecules 7 have good wettability with the front and rear alignment films 3 and 4 and have poor wettability with the left and right alignment films 5 and 6. Are horizontally aligned along the front and rear alignment films 3 and 4.

In this case, the alignment of the ferroelectric liquid crystal molecules is controlled in four directions, that is, front and rear, left and right, and the stable state thereof is determined to be one, and becomes a monostable state. Therefore, unlike the case of bistability, a natural gradation can be provided by applying a voltage stepwise with, for example, a step pulse waveform.

FIG. 2 shows an example of alignment of a nematic liquid crystal.

In this case, the upper and lower alignment films 8 and 9 are fluorine-based alignment films. The front and rear alignment films 10 and 11 are non-fluorine-based alignment films. The left and right alignment films 12, 13 are also non-fluorine-based alignment films.

With such an alignment film configuration, the alignment of the nematic liquid crystal molecules 14 is controlled in six directions: front and rear, left and right, and up and down, so that the nematic liquid crystal molecules 14 wet the front and rear alignment films 10 and 11 and the left and right alignment films 12 and 13. Since the liquid crystal molecules have good wettability and poor wettability with the upper and lower alignment films 8 and 9, the long axis of the liquid crystal molecules is
0 and 11 and the left and right alignment films 12 and 13 are vertically aligned.

The alignment control as described above can be performed by using a liquid crystal display element,
It can be applied to various liquid crystal elements such as a liquid crystal switch and a liquid crystal shutter.

Hereinafter, an example of a suitable display element to which the above-described alignment control is applied will be described.

This display element uses a low-wavelength semiconductor laser or a light-emitting diode as a light source, an optical fiber (wire or rod-shaped) as an optical waveguide, and a liquid crystal, particularly a high-speed switch, as an optical switch for controlling total reflection. It is possible to use a ferroelectric liquid crystal having a large birefringence difference and to arrange a phosphor on the front surface.

The display element thus configured can be made thin, large, and high-definition, and is very bright because it is a self-luminous type that uses a light source efficiently, and is required for a large screen. A contrast ratio of 500: 1 can be realized.

FIG. 3 shows an example of such a display element, and shows a cross-sectional structure thereof.

In the display device shown in FIG. 3, an optical fiber 23 is fixed on a glass substrate 21 (for example, Corning 7059) by a low refractive index polymer 22, and a liquid crystal layer 24 serving as an optical switch is further provided thereon. A phosphor layer 25 serving as a color conversion member is formed.

On both sides of the liquid crystal layer 24, transparent electrodes 26 and 27 for driving the liquid crystal layer 24 are formed as, for example, XY matrix electrodes, and an alignment film for aligning the liquid crystal molecules of the liquid crystal layer 24. 28 and 29 are formed.

The liquid crystal layer 24 must be sealed in a cell. A cell is formed by arranging a glass substrate 30 facing the glass substrate 21 at a predetermined distance from the glass substrate 21, and a liquid crystal material is filled in the cell. It is formed by. Therefore, the one transparent electrode 27 and the alignment film 29 are formed on the glass substrate 30.

The optical fiber used here is a wire or rod made of an inorganic material or an organic material, and is different from a three-dimensional waveguide formed on a substrate, and is different from a three-dimensional waveguide formed on a substrate. It is a simple substance.
The length is sufficiently large as compared with the waveguide diameter.

The cross-sectional shape of the optical fiber is arbitrary and is not particularly limited, but may be, for example, a circle, a polygon, or the like. Ferroelectric liquid crystals can be aligned with good contrast even on a semi-cylindrical shape.

This optical fiber is used by being fixed to a substrate with a polymer having a low refractive index.

The polymer type three-dimensional optical waveguide formed on the substrate is coated uniformly beforehand to obtain a three-dimensional structure.
It must be etched. Micron-order processing accuracy cannot be obtained by chemical etching, and reactive ion etching (RIE) is required to increase processing accuracy.
However, in this case, the surface of the waveguide is roughened, and the light loss is increased. Actually, when comparing the optical loss between the polymer type three-dimensional waveguide and the polymer type optical fiber, 0.16 dB / cm (at a wavelength of 633 nm) (KS Brown, et. Al., “Characterization of P
oly (Phenylsilsesquixane) Thin-Film Planar optical
Waveguides ”, IEEE Photonics Technology Letters,
Vol. 9, No. 6, 1997) and 0.4 dB / m (wavelength 633)
nm) and the difference is evident.

On the other hand, the liquid crystal material used for the liquid crystal layer is arbitrary, but a ferroelectric liquid crystal or an antiferroelectric liquid crystal is preferable.

Since the ferroelectric liquid crystal has a composition containing a large number of tricyclic molecules, it is characterized by a large birefringence difference, unlike a general nematic liquid crystal in which a large number of bicyclic molecules are contained. In an optical switch that controls total reflection using a change in refractive index, the loss is smaller as the birefringence difference is larger. In particular, a ferroelectric liquid crystal has a response speed of the order of microseconds (the response speed of a nematic liquid crystal is of the order of milliseconds) because the permanent dipole of the liquid crystal molecules itself acts on an applied electric field. It can sufficiently cope with driving of a high-definition display represented by definition.

The display time of one pixel is as follows. In the case of HDTV of an interlace signal, when simple matrix driving is performed without using an active element or the like, 1/30 Hz / 1125 lines = 29.6 μsec. In the case of UXGA of a progressive signal, 1/60 Hz / 1200 lines = 14 μs.

As shown in FIG. 4, the effective refractive index n _eff of the liquid crystal is expressed by the following equation (1), where φ is the angle between the long axis of the liquid crystal molecules and the incident direction of the light beam polarized parallel to the substrate surface. ,
(Y. Sadorihara, et. Al., Technology Report of the
0saka University, Vol. 42, No. 2091, pp. 137, 19
92), by controlling the orientation direction, n⊥ <n _eff <n
Take a value in the range //.

[0051]

(Equation 1)

(N //: refractive index in the major axis direction of liquid crystal molecules, n
⊥: Refractive index in the short axis direction of liquid crystal molecules) The most important point in designing an optical switch is controlling the refractive index of the liquid crystal. on·
In order to optimize the OFF ratio, n _eff in the ON state and the OFF state is selected as follows.

_Assuming that n _eff ^OFF is off and n _eff ^ON is on, the above equation can be rewritten as the following equation (2), where n _eff ^OFF <n _f <n _eff ^ON ( _nf : refractive index of the optical fiber). Here, θ is a tilt angle when a certain liquid crystal composition and an alignment film are used (see FIG. 4).

[0054]

(Equation 2)

The alignment direction of the liquid crystal is (φ + θ). At this time, in order to select φ, the following is considered from the relationship with the refractive index of the optical fiber. As an example, n⊥ is 1.493, n
// is 1.667, θ is 20 °, and the refractive index is 1.
Assuming that 59 optical fibers are used, the relationship between φ and the effective refractive index n _eff is calculated as shown in FIG. Therefore,
When φ is 31 °, the difference from n _f is the largest both on and off. Therefore, the orientation direction may be set to 41 °.

Although the necessary conditions for the refractive index of the liquid crystal differ depending on the tilt angle and the refractive index of the optical waveguide, the refractive index n⊥ in the minor axis direction is less than the refractive index of the cladding layer or the core layer of the optical waveguide. It is preferable that the rate anisotropy Δn is 0.1 or more.

As the optical shutter, for example, a mechanical shutter or the like can be used.

As a light source, a near ultraviolet or blue wavelength is used. Low energy ultraviolet light having a large energy is useful for the phosphor, but many liquid crystal and polymer organic substances have ultraviolet absorption, and deterioration is expected. Also, the problem of transparency to ultraviolet light can be avoided.

As the color conversion member, a phosphor is used in consideration of quantum efficiency.

For example, when a blue light emitting element is used,
The conversion efficiency when a green light emitting element is used is compared (assuming that the quantum efficiency of the phosphor is 1).

Blue-green conversion efficiency and blue-red conversion efficiency λB / λG, λB / λR green-blue conversion efficiency and green-red conversion efficiency (1/2) λG / λB, λG / λR red-blue conversion efficiency Red-green conversion efficiency (1/2) λR / λB, (1/2) λRG / λG Suppose blue 470 nm, green 550 nm, red 620 n
m, 64.8% for both green and red when the light emitting element is blue, 51.9% for both blue and red when the light emitting element is green, and both blue and green when the light emitting element is red. 37.2%. If the wavelength is lower than that of the light emitting element, the conversion efficiency decreases. Therefore, it is preferable to use a light source having a wavelength of blue or less.

When a blue laser is used as the light source, a laser dye organic phosphor may be used for the color conversion member of the blue pixel. This is to avoid the speckle effect which is one of the characteristics of the laser. Organic phosphors are good at color conversion with a wavelength shift of about the Stokes effect, and therefore have a wide range of material choices.

The above is the basic structure of the display element to which the present invention is applied. A low-wavelength semiconductor laser or a light-emitting diode is used as a light source, and an optical fiber (wire or rod-shaped) is used as an optical waveguide. Then, the calculation results of the transmission loss of a display using a liquid crystal as the optical switch for controlling total reflection, particularly a ferroelectric liquid crystal capable of being a high-speed switch and having a large birefringence difference, and having a phosphor disposed on the front surface are shown.

Light source coupling 80% × waveguide loss 80% × optical switch efficiency 80% = 51% Ultraviolet-visible conversion efficiency = 90% External light reflection + visible light utilization rate = 70% LD or LED power efficiency = 25% Total = 8% (12.5 times) The required power of the excitation source is π × 200 nit = 628 lm / m ² (683 lm = 1 W at when a display of 100 inch size (3.1 m ² ) at a luminance of 200 nit is considered. R 612 nm Relative luminosity 0.50 205 lm / m ² 0.6 W / m ² 1.86 W G 530 nm Relative luminosity 0.86 353 lm / m ² 0.6 W / m ² 1.86 W B 470 nm Relative luminosity 0.17 70 lm / m ² 0.6 W / m ² 1.86W Total 5.58W. Although it is an ideal value, the efficiency is considerably high. 4O
When it is difficult to uniformly align liquid crystals over the entire screen in manufacturing a large display of not less than inches, after forming a low refractive index polymer layer 32 on an alignment film 31 as shown in FIG. A space 33 may be left only in the pixel portion, and a liquid crystal material 34 may be put in the space 33 and covered with a low refractive index polymer. At this time, the liquid crystal is not injected but is applied in a coating type. Since the pixel area is about 1 mm ² even if it is 100 inches, the alignment of the liquid crystal becomes easy.

The orientation of the ferroelectric liquid crystal in a monostable / hemi-stable state may be selected.

[0066]

Next, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited to these examples.

Example 1 A glass substrate (trade name: 7059: 40mm × 2, manufactured by Corning Incorporated) on which a transparent electrode (ITO) was sputtered with a thickness of 30 nm.
Non-fluorine-based polymer and fluorine-based polymer (manufactured by NTT Advanced Technology) on 5 mm x 1.1 mm)
(Refractive index: 1.49)
It was processed as shown in FIG.

The wettability between the non-fluorinated polymer and the ferroelectric liquid crystal composition is good, and the contact angle is almost zero. The wettability between the fluoropolymer and the ferroelectric liquid crystal composition is poor, and the contact angle is almost 80. Degrees.

A ferroelectric liquid crystal composition (Sony Arakawa, et. Al., Mol.
t. Liq. Cryst., 204, 15, 1991) was injected at 100 ° C.

For response of the liquid crystal, an arbitrary waveform generator is used to generate a step pulse waveform (pulse width 1) as shown in FIG.
00 μ, 0.1 V step). The measurement of transmittance by liquid crystal is performed by a photomultiplier tube (Hamamatsu Photonics)
Was performed by converting the amount of transmitted light into a voltage. Figure 8 shows the experimental results.
Shown in

It can be seen that the transmittance is changed by the intensity of the applied electric field in spite of the ferroelectric liquid crystal element.

COMPARATIVE EXAMPLE 1 For comparison, the same ferroelectric liquid crystal was used for a cell in which the same substrate was used, and only the polyvinyl alcohol alignment film was applied to the upper and lower substrates and rubbing treatment was performed to control the alignment. Similar measurements were made. FIG. 9 shows the experimental results.

In this case, a sharp threshold characteristic is exhibited.

Example 2 A glass substrate (manufactured by Corning, trade name: 7059: 40 mm × 2) on which a transparent electrode (ITO) was sputtered with a thickness of 30 nm.
Non-fluorine-based polymer and fluorine-based polymer (manufactured by NTT Advanced Technology) on 5 mm x 1.1 mm)
(Refractive index: 1.49)
It was processed as shown in FIG.

The wettability between the non-fluorine alignment films 10 and 11 and the nematic liquid crystal for VA is good, the contact angle is almost zero degree, and the contact angle with the non-fluorine alignment films 12 and 13 is about 5 °. .

The wettability between the fluorine-based alignment films 8 and 9 and the ferroelectric liquid crystal composition is poor, and the contact angle is about 80 degrees.

A nematic liquid crystal composition for VA (manufactured by Merck) was injected at 100 ° C. into the processed cubic space.

A rectangular wave was used for the response of the liquid crystal, and white and black were displayed alternately. Observation of the domain inversion portion under a microscope revealed that the inversion portion was clearly reduced as compared with the case where only the alignment films on two normal substrates were used.

Example 3 First, a low refractive index polymer (manufactured by Asahi Glass Co., Ltd., Cytop: 1.34) was coated on the entire surface of a 40 mm × 25 mm × 1.1 mm glass substrate (manufactured by Corning, trade name: 7059). Was applied to a thickness of 50 μm using a squeegee.

Next, after precuring at 80 ° C. for 60 seconds, a polycarbonate optical fiber (refractive index: 1.59,
Fiber diameter 1 mm: Adjust the refractive index of the cladding layer and the core layer, the difference is 0.01 or less, and arrange 10 lines (Polycarbonate optical fiber has refractive index between birefringence of liquid crystal and heat resistance) And calcined at 120 ° C. for 1 hour.

As shown in FIG. 3, a transparent electrode (ITO) was RF magnetron sputtered to a thickness of 20 nm using the OFF AXIS method so as to form a pixel perpendicular to the optical fiber.

Further, polyvinyl alcohol (P
VA) Spin coat thin film (degree of polymerization 5OO, 1% by weight)
Aqueous solution, 200 rpm 5 seconds + 2000 rpm 20 seconds), 11
It was baked at 0 ° C. for 1 hour.

Next, a non-fluorine-based polymer and a fluorine-based polymer (manufactured by NTT Advanced Technology) (refractive index: 1.49) were processed by wet etching as shown in FIG.

The wettability between the non-fluorine polymer and the ferroelectric liquid crystal composition is good, and the contact angle is almost zero. The wettability between the fluorine polymer and the ferroelectric liquid crystal composition is poor, and the contact angle is about 80. Degrees.

As a counter substrate, 10 lines of I
On a glass substrate with a TO transparent electrode (40 mm x 25 mm x
(0.1 mm) to form a PVA rubbing alignment film.

Further, a fine particle type inorganic phosphor (ZnS: Cu, Al) was formed to a thickness of 50 μm on the glass substrate on which the transparent electrode was not formed by using a sedimentation method.

The two substrates were combined so that their orientation directions were antiparallel, and bonded together with an ultraviolet curable resin mixed with 0.15% by weight of a 3.0 μm spacer (manufactured by Catalyst Kasei Co., Ltd.). In the gap, a ferroelectric liquid crystal composition of 100
Injected at ° C. The cross section of the fiber was circular,
Good orientation was obtained.

The wavelength of the incident light was 550 nm, and the polarization direction of the light was parallel to the substrate surface. The input / output coupling was performed using a TiO ₂ rutile prism.

For response of the liquid crystal, an arbitrary waveform generator is used to generate a step pulse waveform (pulse width 1) as shown in FIG.
00 μ, 0.1 V step). The measurement of transmittance by liquid crystal is performed by a photomultiplier tube (Hamamatsu Photonics)
Was performed by converting the amount of transmitted light into a voltage.

Although the device is a ferroelectric liquid crystal device, the transmittance is changed by the applied electric field intensity. In addition, emission of fluorescence was also confirmed.

Comparative Example 2 First, a low refractive index polymer (manufactured by Asahi Glass Co., Ltd., Cytop: 1.34) was coated on the entire surface of a 40 mm × 25 mm × 1.1 mm glass substrate (manufactured by Corning, trade name: 7059). Was applied to a thickness of 50 μm using a squeegee.

Next, after pre-curing at 80 ° C. for 60 seconds, a polycarbonate optical fiber (refractive index: 1.59,
Fiber diameter 1 mm: Adjust the refractive index of the cladding layer and the core layer, the difference is 0.01 or less, and arrange 10 lines (Polycarbonate optical fiber has refractive index between birefringence of liquid crystal and heat resistance) And calcined at 120 ° C. for 1 hour.

As shown in FIG. 3, a transparent electrode (ITO) was RF magnetron sputtered to a thickness of 20 nm using the OFF AXIS method so as to form a pixel perpendicular to the optical fiber.

Further, polyvinyl alcohol (P
VA) Spin coat thin film (degree of polymerization 5OO, 1% by weight)
Aqueous solution, 200 rpm 5 seconds + 2000 rpm 20 seconds), 11
It was baked at 0 ° C. for 1 hour and rubbed.

As a counter substrate, 10 lines of I
On a glass substrate with a TO transparent electrode (40 mm x 25 mm x
(0.1 mm) to form a PVA rubbing alignment film.

Further, a fine particle type inorganic phosphor (ZnS: Cu, Al) was formed to a thickness of 50 μm on the glass substrate on which the transparent electrode was not formed by using a sedimentation method.

The two substrates were combined so that the orientation directions were antiparallel, and bonded together with an ultraviolet curable resin mixed with 0.15% by weight of a 3.0 μm spacer (manufactured by Kasei Kasei Co., Ltd.). In the gap, a ferroelectric liquid crystal composition of 100
Injected at ° C. The cross section of the fiber was circular,
Good orientation was obtained.

The wavelength of the incident light was 550 nm, and the polarization direction of the light was parallel to the substrate surface. The input / output coupling was performed using a TiO ₂ rutile prism.

The response of the liquid crystal was performed in the same manner as in the example. In this case, a threshold voltage response unique to the ferroelectric liquid crystal element was confirmed.

[0100]

As is clear from the above description, according to the present invention, it is not necessary to use a spacer which is indispensable for controlling the gap of the liquid crystal element.

Further, it is possible to eliminate a contacting step such as a rubbing treatment which is difficult to display uniformly.

Therefore, for example, it has been considered very difficult to uniformly align ferroelectric liquid crystals on a large screen. However, if this method is adopted, the surface area of the liquid crystal element portion is about one pixel. The maximum size does not exceed several square millimeters, and it is very easy to enlarge the screen, which is practical in the manufacturing process.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of alignment of ferroelectric liquid crystal molecules.

FIG. 2 is a schematic view showing an example of alignment of a nematic liquid crystal.

FIG. 3 is a schematic sectional view of a main part showing an example of a display element to which the present invention is applied.

FIG. 4 is a schematic diagram showing a relationship between a light guiding direction and a liquid crystal molecule position in a ferroelectric liquid crystal.

FIG. 5 is a characteristic diagram showing φ dependence of an effective refractive index.

FIG. 6 is a schematic diagram illustrating an example of a liquid crystal switching element structure for a large screen.

FIG. 7 is a waveform chart showing a step pulse driving waveform for confirming analog intensity modulation.

FIG. 8 is a characteristic diagram showing the applied voltage dependence of the amount of transmitted light in an example.

FIG. 9 is a characteristic diagram showing the applied voltage dependence of the amount of transmitted light in a comparative example.

[Explanation of symbols]

1,2,8,9 Vertical alignment film, 3,4,10,11 Front and rear alignment film, 5,6,12,13 Left and right alignment film, 7 Ferroelectric liquid crystal molecule, 14 Nematic liquid crystal molecule, 21,30
Glass substrate, 22 Low refractive index polymer, 23 Optical fiber, 24 Liquid crystal layer, 25 Phosphor layer, 26, 27 Transparent electrode, 28, 29 Alignment film

Claims (6)

[Claims] 1. A liquid crystal device comprising a liquid crystal arranged in a cell, wherein alignment control of liquid crystal molecules is performed three-dimensionally from three directions or more. 2. The liquid crystal device according to claim 1, wherein the alignment control is performed by combining two or more types of alignment films having different interface mutual energies. 3. The alignment film in the liquid crystal molecule long axis direction has a contact angle with respect to the liquid crystal molecule long axis of less than 45 °, and the alignment film in the liquid crystal molecule short axis direction has a contact angle with the liquid crystal molecule long axis of 45 ° or more. 3. The liquid crystal device according to claim 2, wherein 4. A liquid crystal display device, a liquid crystal switch, and a liquid crystal shutter selected from one type.
The liquid crystal element according to the above. 5. The liquid crystal device according to claim 1, wherein the liquid crystal is a smectic liquid crystal. 6. The liquid crystal device according to claim 1, wherein the liquid crystal is a nematic liquid crystal.