JPS5826006B2 - lcd cell - Google Patents

Description

[Detailed description of the invention] The present invention relates to a liquid crystal device.

Recently, among liquid crystal devices that utilize electro-optic effects for display purposes, twisted nematic devices have attracted the most attention.

This device creates a twisted nematic cell and places this cell between optical polarizers.

The most common way to make a cell is to gently scratch the surfaces of two glass substrates, slides or plates, on which transparent conductive electrodes have been deposited, in one direction, with the directions of the scratches perpendicular to each other. The idea is to place the surfaces facing each other and introduce a layer of nematic liquid crystal material between the surfaces.

The molecules in the layer have an elongated shape.

The molecules directly adjacent to the surface are aligned with their long molecular axes along the rubbing direction.

Inside the layer, the molecules are arranged along the middle direction of a helical shape in which the direction of the long axis of the molecules is twisted (twirled) gradually and continuously over the thickness of the layer.

In operation, applying an electric field between transparent conductive electrodes on the two inner surfaces of the cell causes a reorientation of the liquid crystal molecules, modulating the intensity of light transmitted through the twisted nematic device. Ru.

It has been shown that liquid crystal molecules directly adjacent to abraded surfaces are not precisely aligned within those surfaces, but are generally offset on average by about 2 degrees with respect to the direction of abrasion of those surfaces.

Instead of aligning the liquid crystal molecules using the scratching technique, the liquid crystal molecules may be aligned using the known "oblique deposition" technique.

Molecules of a transparent dielectric substance are deposited onto a suitable surface of a transparent substrate in a fixed direction at a fixed angle with respect to the substrate surface to form a coating.

Hereinafter, the above direction will be referred to as the "oblique deposition direction" and the above angle will be referred to as the "incident angle".

The coating treatment is already applied on the surface (also on the transparent conductive electrodes arranged on this surface).

Coating treatment (this causes liquid crystal molecules to be aligned.

When the oblique deposition technique is carried out at an angle of incidence below a critical value (approximately 15° C.), the liquid crystal molecules form a similar alignment as when using the scratching technique.

That is, it is well known that the axes of liquid crystal molecules directly adjacent to a glass surface make a general angle with said surface.

However, in this case the average angle is approximately 300 degrees instead of 2 degrees.

When using the oblique deposition technique at an angle of incidence greater than said critical value, i.e. greater than about 15° and less than another critical value (about 45°), the liquid crystal molecules will also form another alignment, with the axis of the liquid crystal molecules It is also well known that the average direction is aligned throughout the liquid crystal layer in the plane of the glass surface.

For simplicity of expression, it consists of two substrates and a layer of liquid crystal material between the inner surfaces of the substrates, the two substrates are arranged to face each other, and an electrode material layer is provided on the inner surface of each substrate. is deposited, at least one substrate and its electrode material layer are optically transparent, and further, the molecular axis of the liquid crystal material layer between the two inner surfaces is oriented from the inner surface of the one substrate. Liquid crystal cells which are arranged along a local mean direction that is gradually (twisted) towards the inner surface of another substrate will hereinafter be referred to as "cells of the above type".

"Optically transparent" means transparency in the ultraviolet, infrared, and visible regions of the spectrum.

If the liquid crystal material is nematic and the inner surface of the optically transparent substrate is coated with any of the above-mentioned methods, i.e., scratching or oblique deposition at an angle of incidence of less than about 15°, or oblique deposition at an angle of incidence in the range of about 15° to about 45°. Two problems arise when a liquid crystal cell of the type described above is processed.

As a result, devices incorporating such cells are viewed incompletely or inconsistently depending on the viewer's viewing angle.

This is a serious drawback, especially for display devices.

These two problems can be solved by ``reverse twist'' (reverse twist).
"e twist" and "reverse tip"
tip)” and will be explained below.

British Patent Application No. 8042774 (% opening/closing 50-143
No. 557) discloses one method by which reverse twist°' and "reverse tip°" can be prevented.

A liquid crystal cell of the above type according to the invention comprises as liquid crystal material:
The axes of the molecules of the liquid crystal material immediately adjacent to the inner surfaces of one substrate include an intrinsically optically active material having an intrinsic molecular helical pitch that is at least twice the spacing between the inner surfaces of the two substrates of the cell; forms an angle with said inner surface, and the mean direction of the axes of the molecules of the liquid crystal material directly adjacent to the other substrate inner surface is parallel to said other inner surface.

"Intrinsically optically active material" refers to a material that is optically active only when used in a cell, i.e., a pure nematic material, and a material that is optically active whether or not it is used in a cell. It is used for identification.

Examples of liquid crystal substances having optical activity are as follows.

(I) A normal cholesteric liquid crystal substance whose helical molecular arrangement has an appropriate pitch = (II)
A mixture of a nematic substance and a cholesterogenic substance (exhibiting a cholesteric liquid crystal phase), with a mixing ratio such that the helical molecular arrangement has an appropriate pitch: (D) A mixture of a nematic substance and a non-crystalline optically active substance. A mixed substance with a mixing ratio such that the helical molecular arrangement has an appropriate pitch.

Preferably, any of the interior surfaces have an angle of incidence of about 15° to about 4
The cell is manufactured by applying an oblique deposition technique in the range of 5° and then treating said one inner surface with an abrasion technique before introducing an optically active liquid crystal material between the inner surfaces.

In this case, the rubbing direction is set perpendicular to the projection (Q ro projection ) of the oblique deposition direction on the one inner surface.

Alternatively, the one inner surface may be treated solely by abrasion techniques or by oblique deposition techniques at an angle of incidence of less than about 15 degrees.

In twisted nematic cells produced by any of the above-mentioned known methods, the problem of the above-mentioned "reverse twist" occurs as follows.

Ideally, the molecular alignment in a twisted nematic cell is of a single twist, so that the plane of polarization of light passing through the cell is rotated in a single direction.

However, if the liquid crystal material is an intrinsic nematic substance, when no electric field is applied, the molecules will form an arrangement that is twisted in one direction in some parts and twisted in the opposite direction in other parts. .

This arrangement is permanent because the torsional energy of the former is equal to that of the latter.

Similarly, in twisted nematic cells manufactured by any of the above-mentioned known methods, the above-mentioned "reverse tip" problem occurs as follows.

When an electric field is applied between the transparent conductive regions (ie, electrode portions) on the inner surface of each of the two transparent substrates of the twisted nematic cell, the liquid crystal molecules are reoriented in the electric field.

The strength of the reorientation increases as it goes inside the liquid crystal layer.

The molecules inside the layer are initially aligned in the plane of the two inner surfaces.

As a result, these molecular numbers are energetically favorable, with some molecules being reoriented clockwise in the electric field and some molecules being reoriented counterclockwise in the electric field.

In the device of the present invention, the problem of "reverse twist" is solved by using the above-mentioned optically active liquid crystal material whose liquid crystal molecules have the property of twisting in only one direction.

Further, the liquid crystal molecules directly adjacent to said one inner surface are arranged at an angle generally to said surface, and the liquid crystal molecules directly adjacent to said other inner surface are arranged entirely in the plane of said surface. By treating the inner surface of the substrate in such a way that all the molecules within the layer are reoriented in the same direction within the electric field, the problem of ``reverse tip'' was also solved.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

A method for manufacturing the above-mentioned type of liquid crystal cell according to the present invention will be described below.

Carefully wipe the surfaces of two glass slides (thin glass plates) that act as optically transparent substrates.

A thin coating of a transparent conductive material, such as tin oxide, is applied to the surface or a portion of the surface of each slide by known methods to constitute an electrode.

To create a coating on a portion of each slide surface, for example, a coating may be first deposited and then photoetched in sections.

Next, the oblique vapor deposition technique f described below in relation to FIG.
Coat the slide with this powder.

FIG. 1 (In the illustrated apparatus, a bell-shaped container 21 is placed on an insulating substrate 23 having a suction port 25, and a vacuum pump (not shown) communicating with the suction port 25 is used to remove the bell-shaped container 21. is vacuum strained.

A crucible 27 made of tungsten or molybdenum is placed inside and at the bottom of the bell-shaped container 21, and several grams of magnesium fluoride crystals 28 are placed in the crucible 27.

The crucible 27 has two lower arms 27a, 27b, each of which is connected to a conductor 29.31.

Conventional type power source 33 and switch 35 are in bell-shaped container 2
It is connected in series between the external conductors 129 and 31 of 1.

The glass slide 37 is placed in the crucible 2 inside the bell-shaped container 21.
7 and at an angle θ with respect to the vertical axis of the bell-shaped container 21.

However, θ is 15° <θ × 45°.

When the switch 35 is opened, the bell-shaped container 21 is first brought into a vacuum state of approximately 10"-5 mrnHg pressure, and then the switch 35 is closed, and the crucible 27 is heated to a suitable temperature and the magnesium fluoride crystals 28 are evaporated. Power is supplied by adjusting the power supply 33 until the

The required current for a suitable temperature range (700-1000°C) is about 100100A.

The magnesium fluoride crystals are then evaporated to form an upward molecular stream indicated by S in the figure, and the fluid S is incident on the glass slide 37 at an angle θ with respect to the slide 37, resulting in Glass slide 37 is coated.

The angle θ is the above-mentioned "incident angle", and the direction of the fluid S is the above-mentioned "oblique deposition direction".

The thickness of the coating is generally 100 to 1000 angstroms.

This value is determined by a thickness versus time calibration of the device, which is performed before inserting the glass slide 37 into the bell container 21.

When a coating of appropriate thickness is formed, the power from the power supply 33 is reduced and the switch 35 is opened to cool the bell-shaped container 21 and its interior.

Next, the pressure is increased to atmospheric pressure and the glass slide 37 is removed from the bell-shaped container 21.

The material used to form the molecular coating is preferably magnesium fluoride, but is not limited thereto.

Silicon monoxide or other suitable optically transparent material may be used instead.

However, these substances must be electrically insulating and have no electrical influence on the transparent conductive coating.

The two glass slides that make up the above type of cell are:
Each is coated in a manner similar to the coating of glass slide 37 described in connection with FIG.

The two slides may be coated separately or together.

In either case, the two slides are arranged so that the surfaces thereof each having a transparent conductive coating face the fluid S and form the same angle θ with respect to the fluid S.

After coating the slides by oblique deposition.

The coated surface of one slide is rubbed approximately 5 times in one direction with a soft fiber such as wool or cotton using the conventional rubbing method described above.

The direction (1) is a rubbing direction that is perpendicular to the projection on the slide of the oblique deposition direction, that is, the direction of the fluid S with which the slide is coated.

This is because the projection of the liquid crystal molecules on the slide is usually aligned along a direction perpendicular to the projection on the slide in the oblique deposition direction.

This is due to the use of an angle of incidence for oblique deposition in the range of approximately 15° to 45°.

After rubbing one of the slides, the two slides were brought close to each other in parallel so that the coated surfaces of each were facing each other, and the thickness of the typical liquid crystal layer was about 15'μm (15×10-6).
m) Install at a distance.

Also, the coating surfaces of the two slides are arranged with respect to each other such that the projections of the oblique deposition direction on the slides are perpendicular to each other.

Next, by filling the gap between the two slides with a suitable optically active liquid crystal material, the problem of 6 reverse twists described above is solved.

For example, the slides are separated by spacers and the liquid crystal material is guided into the gap by capillary action to form a liquid crystal layer.

Liquid crystal molecules are naturally oriented as follows.

The liquid crystal molecules directly adjacent to the non-abrasive slide are usually in the plane of the slide and aligned along a direction perpendicular to the projection of the deposition direction onto the slide.

For liquid crystal molecules directly adjacent to the abraded slide, the long molecular axes are aligned along a direction that makes a small angle, about 2°, to the abraded slide.

The projection in this direction is at right angles to the projection on the slide of the oblique deposition direction.

A plurality of liquid crystal molecules within the layer are oriented in various directions, changing between the molecular directions directly adjacent to the two slides.

In order to explain the problem of "reverse tip" that occurs in twisted nematic cells due to the above-mentioned known causes, we first consider a simple nematic liquid crystal cell without twist, that is, when the projections of monetary molecules on a glass slide are in the same normal direction. Consider a cell,
Next, assume that one of the slides is rotated 90 degrees around its shared axis.

First, let us consider the case where a simple nematic liquid crystal cell is fabricated by performing only oblique vapor deposition on the surface of a glass slide at an incident angle of 15° to 45°.

Figure 2a shows the molecular arrangement of this cell.

All liquid crystal molecules, designated M, are generally oriented in the same normal direction within the plane of the slide designated M.

If one of the slides is now rotated 90° around an axis Z1 perpendicular to slide L, the molecules directly adjacent to one slide L will normally be perpendicular to the molecules directly adjacent to the other slide L, and the liquid crystal layer Inside the molecule, the molecule is usually tilted between 0° and 90° across said molecule directly adjacent to one slide L.
° Gradually change the angle.

However, the molecule M normally remains within the plane of the slide L.

The 90 DEG rotated array shown in FIG. 2a is the same structure as the twisted nematic cell array.

That is, in twisted nematic cells. Before inserting the liquid crystal material between the slides L, the slides L are initially arranged so that the projections on each slide of the oblique deposition direction are at right angles to each other.

Therefore, the liquid crystal molecules in the twisted nematic cell.

Similar to the 900 rotation alignment shown in Figure 2a, it is in the plane of the slide, resulting in the "reverse tip" problem described above when an electric field is applied.

Next, let us consider the case where a simple nematic cell is made by subjecting the slide L to a scratching process or an oblique vapor deposition process at an incident angle of 15 DEG or less - the results are the same regardless of the method.

The projections of the cells in the alignment direction on the slide L, that is, the scratching direction or the oblique vapor deposition force direction, are aligned in parallel from the beginning.

The liquid crystal molecules immediately adjacent to each slide L of the cell are generally aligned obliquely to the inner surface of the slide.

As a result, two alignments of the liquid crystal molecules M are possible depending on whether the two alignment directions are the same or opposite.

Figure 2b shows one arrangement and Figure 2c shows the other arrangement.

In the arrangement of FIG. 2b, the molecules M form a "splay" that dries out toward the interior of the liquid crystal layer.

The internal molecules M remain within the plane of the slide L.

In the arrangement of FIG. 2c, the molecules M are in a "tilted state", with all molecules tilted in a single direction with respect to the slide L.

Next (one of these slides L moves 9 times around axis Z1 in the same plane)
Suppose it is rotated by 0°.

In this case, liquid crystal molecules directly adjacent to the rotated slide L rotate together with this slide L.

In the arrangement shown in Figure 2b, even if one of the slides L is rotated, the molecules M inside the layer remain in the plane of the slide L, and as shown in Figure 2c. In the molecular arrangement state, even if one of the slides L is rotated, the molecules M remain tilted with respect to both slides L throughout the layer.

The 900 rotation alignment illustrated in FIGS. 2b and 2c each correspond to two configurations of twisted nematic cells.

that is, twisted nematic cells made by the well-known method of scratching or oblique deposition on both slides at an angle of incidence of less than 15° (in which the molecules are exposed to one of the slides L shown in Figure 2b). Arranged in the same "splay" configuration as the arrangement with 900 rotations, or in the second c.
They are arranged in a "tilt" shape, which is the same as the arrangement when one of the slides L shown in the figure is rotated by 90 degrees.

As mentioned above, when the molecules inside the product layer are within the slide plane, the above-mentioned "reverse tip" problem occurs.

Therefore, a "splay" type cell would have the problem of "one inverted tip", but a "tilt" type cell would not have this problem.

The "tilt" shaped cell is described in the applicant's UK patent application 804.
Using an optically active substance, as described in 2/74,
This is obtained by making the twist direction defined by the alignment direction on the two slides L oppose the inherent helical direction of the liquid crystal molecules.

Consider now a simple nematic cell made in the same manner as the above type of cell according to the embodiment of the invention described with reference to FIG. 1, but with their respective alignment directions parallel.

In other words, parallel rubbing is performed in a direction perpendicular to the projection of the rubbing direction on the rubbed slide and the oblique deposition direction on the unrubbed slide.

The arrangement of molecules M within this simple nematic cell is shown in Figure 2d.

The molecule M is tilted with respect to the slide surface over the entire product layer, except for the surface immediately adjacent to the non-abrasive slide, denoted by LU, and its inclination increases as it approaches the abrasive slide, denoted by LR. increase.

Now consider the case where one of the slides is rotated 90 degrees around the axis Z1.

The molecule M remains tilted with respect to the slide surface over the entire layer except for directly adjacent areas of the slide LU that do not abrade.

The 90° rotated arrangement shown in Figure 2d is structurally
This is identical to the arrangement of cells according to an embodiment of the invention made in the manner described with respect to FIG.

Therefore, in the above cell according to the present invention, the abraded slide (directly) and the non-abrasive slide directly due to the small angle between the adjacent liquid crystal molecules and the slide itself, i.e. 2°.
The molecules are no longer tilted with respect to the sliding plane throughout the layer, except in the adjacent regions.

Furthermore, this tilting completely solves the problem of "reverse tip".

That is, when an electric field is applied between the transparent conductive coatings on each slide, all the internal liquid crystal molecules are reoriented in the same state, ie, in the same direction.

Liquid crystal molecules directly adjacent to a non-scratching slide are never affected by electric fields of any strength and therefore do not participate in the "reverse tip" problem.

In an actual liquid crystal cell, the direction of the liquid crystal molecules in the product layer fluctuates, but the axis of the molecule M in Figures 2a and 2d is aligned along the average molecular direction for each part in the layer. Considering that the above description regarding the above figure is valid.

Molecular orientation fluctuations directly adjacent to the slide are in both cases much less than fluctuations within the layer.

According to another embodiment of the invention, the surface of one slide is
A cell of the type described above may be made by performing oblique deposition at an angle of incidence of between 45° and 45°, and by scraping the other slide without oblique deposition.

The slide is installed so that the projection of the rubbing direction on the rubbed slide and the oblique deposition direction on the other slide are parallel.

This is because the liquid crystal molecules directly adjacent to the scratched slide are aligned along the scratching direction.

Since scratches on the transparent conductive coating are generally not replicable, (first
It is difficult to make cells with this method (compared to the method described with respect to the figure).

According to another embodiment of the invention, the surface of the first slide is
Cells of the type described above may be produced by oblique deposition at an angle of incidence between 5° and 45°, with the second slide being obliquely deposited at an angle of incidence of 15° or less.

As mentioned above, the liquid crystal molecules directly adjacent to the first slide are generally aligned perpendicular to the projection of the oblique deposition direction on the slide, but the liquid crystal molecules directly adjacent to the second slide are generally aligned perpendicularly to the projection of the oblique deposition direction on the slide. Align parallel to the projection of the diagonal deposition direction on the slide.

Therefore, in this case, the first slide and the second slide are arranged so that the projections of the oblique deposition directions on the slides are parallel to each other and an appropriate twist of the liquid crystal molecules is formed.

In this case, the tilt angle of the liquid crystal molecules becomes large and the optical function of the cell deteriorates, so making a cell using this method is difficult (
(compared to the method described in connection with FIG. 1) is disadvantageous.

The gap between the two glass slides in the liquid crystal cell is typically about 15 μm.

In cells of the above type, the molecules of the liquid crystal material are arranged in a 90° helical twist about the gap between the slides.

The molecular arrangement of this liquid crystal material is twice the gap between the slides,
That is, an intrinsic helical pitch (3600 turns) of 30 μm or more is required, but the intrinsic pitch is approximately 30 μm or more, such that when the molecules are placed between the slides, they are twisted by π/2 (900) and then rearranged. The thickness is preferably 80 μm.

If the pitch is less than twice the gap length (in this case, the molecule is m
Such a small pitch is unsuitable because it is rearranged at an angle of π/2 (where m is an odd integer greater than 1).

Suitable liquid crystal materials with an intrinsic helical molecular pitch of appropriate dimensions are made, for example, by diluting a nematic liquid crystal material with an optically active material (which may or may not be a cholesteric liquid crystal material).

It is desirable for the nematic material to have a positive dielectric anisotropy state (ie, the difference between the dielectric coefficient measured parallel to the molecule and the dielectric coefficient measured perpendicular to the molecule).

Suitable nematic materials include R such as n c
5H, or nC3)it□0 or other biphenyls or alkoxy groups).

Additives mixed with the nematic material usually do not exceed 2% by weight.

A cholesteric substance suitable for mixing and diluting the nematic substance is, for example, cholesteryl nonanoate (mixing ratio with the nematic substance is 0.2% by weight).

A suitable method of mixing is described below.

Appropriate amounts of a nematic substance and a cholesteric substance are placed in a small beaker, heated with stirring above a temperature at which isotropic constriction is induced (that is, the liquid becomes transparent), and then allowed to cool naturally.

When using a mixture of a nematic nocturnal substance and a non-cholesteric optically active substance, similarly place appropriate amounts of the nematic substance and non-cholesteric substance in a small beaker.
It is heated to a temperature above which a nematic isotropic phase occurs, and then allowed to cool naturally.

The optically active substance is, for example, Canada balsam or (-)C
H3・CH2・compound (mixing ratio with nematic substance is 1
% by weight).

Here, the * mark represents an optically active center.

FIG. 3 is a side sectional view of a simple liquid crystal device.

The cell 1 is installed between the polarizing plate 3 and the analyzing plate 5.

FIG. 4 is a partial front view of only the cell 1 viewed from the X direction.

The cell 1 is constructed according to an embodiment of the invention described above, in which a layer 11 of the liquid crystal material described above is placed between the glass slides 2 and 9.

On the inner surface of slide 7 two electrode pieces 13, 15 are deposited, and on the inner surface of slide 9 two electrode pieces 17.
19 is formed by vapor deposition.

The electrode pieces 13, 15 and 17, 19 constitute the above-mentioned transparent conductive coating, respectively.

The slide 7 and the electrode 13.15 have an area where one edge of the layer 11 and the slide 9 overlap, while the slide 9 and the electrode 17.19 have an area where one edge of the layer 11 and the slide 7 overlap. It has a region that is polymerized.

These overlapping parts are electrically connected to the outside so that electrodes 13, 15, 17, 19 are formed, respectively (not shown).

When no voltage is applied to layer 11, the optical activity of layer 11 is strong.

That is, when no voltage is applied, the layer 11 rotates the polarization plane of incident light by 900 degrees.

However, any suitable voltage, typically between 1 and 3 volts, is applied to layer 11.
, the optical activity of layer 11 is weak.

That is, the region does not rotate the plane of polarization of the light.

The polarizing plate 3 is attached directly to the slide 7 in the normal direction of the adjacent liquid crystal molecules (this is particularly influenced by the arrangement of the cells 1 as described above, but for example, when the slide 7 is polished, the polarized light is The linearly polarized light direction of the plate 3 is parallel to the polishing direction.

The analyzer plate 5 is provided so as to pass linearly polarized light perpendicular to the polarized light that has passed through the polarizing plate 3.

Therefore, when light of a constant intensity is incident on the polarizing plate 3 in the is high, and becomes low if a suitable voltage is applied to the corresponding portion of layer 11.

Layer 11 is divided into four parts where electrodes 13 and 15 intersect with electrodes 17 and 19, respectively.

Therefore, the intensity of the light emitted from the four parts of the polarizing plate 3 corresponding to these four parts can be adjusted by applying an appropriate voltage between the appropriate electrodes 13 and/or electrodes 15 and electrodes 17 and/or electrodes 19. They are individually selected by adding or removing them.

The voltage may consist of a pulse train of positive potential, with a voltage pulse of positive polarity being applied to one electrode and a voltage pulse of opposite polarity being applied to the other electrode.

Alternatively, the voltage may be alternating current. In practice, a character symbol display can be made by arranging a large number of parts, such as the four parts of a global device, for example the four parts of layer 11, into groups of letters, numbers, codes, etc.

In one variation of the apparatus shown in FIGS. 3 and 4, each conductor is connected to a respective electrode, and a voltage is applied to that electrode independently with respect to the other electrodes f to effect the display operation. It is also possible to do so.

In this case, these electrodes form the displayed font or portion thereof.

A simpler variant is for a single electrode to be deposited on the screen of each display (cell).

This simple device can be used as an optical shutter, and depending on the shape of each electrode, it can also be used as a simple display device.

Some examples of embodiments of the present invention are then listed below.

(1) The liquid crystal cell according to claim 1, further characterized in that the liquid crystal substance is a cholesterogenic substance.

2. A liquid crystal cell according to claim 1, further characterized in that the liquid crystal material is a mixture of a nematogenic material and an additive comprising up to 2% by weight of an optically active material.

(3) The liquid crystal cell according to item (2) above, further characterized in that the additive consists of a non-liquid crystal substance.

(4) The liquid crystal cell according to item (2), further characterized in that the additive comprises a cholesterogenic substance.

(5) The nematogenic substance has the general formula kyl or alkoxy group, and CN is a cyano group.
), the liquid crystal cell according to any one of <4).

(6) the inner surface of the second substrate is abraded in a single direction, the abrasion direction being parallel to or forming a small angle to the projection of the oblique deposition direction on the inner surface of the first substrate; The method according to claim 2, characterized in that:

(7) Before the inner surface of the second base is rubbed, a dielectric material coating treatment is applied to the inner surface (obliquely deposited) along the oblique vapor deposition direction, and The direction forms an angle θ1 with respect to the surface such that 45°≦θ1≦15°, and the rubbing direction is arranged perpendicular to the projection of the oblique deposition direction on the inner surface of the second substrate. The method described in the preceding section (6), which is characterized by:

(8) The inner surface of the second substrate is coated with a dielectric material in an oblique vapor deposition direction (along which a dielectric material is obliquely vapor deposited on the inner surface); The inner surface of the substrate is arranged such that the angle θ2 is in the range of 15°〉θ2〉0°, and the projections of the respective oblique deposition directions are parallel to each other or form a small angle. The method according to claim 2.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an apparatus for manufacturing the apparatus according to the present invention, part of which is a side sectional view and part of which is a schematic explanatory diagram of a circuit, and FIGS. 2a to 2d are diagrams showing various types of liquid crystal cells, respectively. FIG. 3 is a side sectional view of a liquid crystal device manufactured by the method of the present invention, and FIG. 4 is a partially cutaway front partial view of the device of FIG. 3. 1...Cell, 3...Polarizer, 5...
...Analysis board, 7°9...Slide, 13,1
5,17.19... Electrode, 21... Pelger, 23... Insulating substrate, 27...
- Crucible, 37...Slide.

Claims (1)

[Claims] 1 Consisting of two opposing substrates, each having an electrode layer deposited on its inner surface, and a layer of liquid crystal material disposed between the inner surfaces of said two substrates, at least one of the substrates and its electrode a liquid crystal cell in which the layers are optically transparent and the liquid crystal molecules within said liquid crystal material are oriented along an average direction that is gradually twisted from one substrate inner surface to the other substrate inner surface in the absence of an applied electric field; wherein the liquid crystal material is an inherently optically active material having an inherent molecular helical pitch that is at least about twice the spacing between the two substrate inner surfaces, and the two substrate inner surfaces have liquid crystal molecules present thereon. 1. A liquid crystal cell characterized in that the liquid crystal cells are processed and arranged between each other so that the average direction of the liquid crystal display is parallel to the inner surface of one substrate and oblique to the inner surface of another substrate.