JP2002530720A - Spiral deformation liquid crystal display device with vertical alignment - Google Patents

Abstract

(57) [Summary] The present invention relates to a vertically-aligned helical deformation liquid crystal display device, and more particularly, to a device of the present invention, comprising a first and a second glass substrate having two surfaces facing each other, and a first and a second glass substrates, respectively. A first transparent electrode formed on one surface and having a first potential; a second transparent electrode formed on a first surface of the first glass substrate and having a second potential different from the first potential; (2) a first vertical alignment film formed on a first surface of a first glass substrate on which a transparent electrode is formed; a second vertical alignment film formed on a first surface of the second glass substrate; A vertical alignment film is sealed between the first and second glass substrates facing each other, has a helical pitch shorter than the wavelength of light, and responds to an electric field formed between the first and second transparent electrodes. A ferroelectric liquid crystal that undergoes helical deformation and molecules rotate in a specific direction Provided on the first the second surface of the polarizing plate and the second glass substrate provided on the second surface of the substrate, including a second polarizer having a polarizing orthogonal to the first polarization plate. Therefore, according to the present invention, uniform vertical alignment of a large area is possible, a high contrast ratio is obtained, continuous deformation is possible according to the magnitude of an electric field, continuous gradation display is possible, and an electrode arrangement on the same substrate is possible. It has wide viewing angle characteristics due to multiple orientations.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a novel liquid crystal display device using a ferroelectric liquid crystal, and in particular, vertically aligns a ferroelectric liquid crystal having a helical pitch shorter than the wavelength of incident light and suppresses the deformation of the helical structure due to the strength of an electric field parallel to the substrate. The direction of rotation of the molecule is controlled through a large area, the orientation is high, the contrast ratio is high, continuous gradation can be displayed, and the vertical alignment helix that can realize a wide viewing angle by arranging the electrodes on the same substrate The present invention relates to a modified liquid crystal display device.

[0002]

[Prior art]

In a conventional liquid crystal display device using the electro-optic effect of liquid crystal, a transparent electrode is formed on each of two substrates, an alignment film capable of aligning the liquid crystal is formed on the electrode surfaces, and the liquid crystal is filled between the substrates. , Each outer surface is provided with a polarizer. Such a conventional liquid crystal display device automatically transmits or blocks incident light to display information on a screen. Therefore, in order to transmit or block light, a voltage must be applied to induce rotation of liquid crystal molecules to change the alignment direction.

On the other hand, the liquid crystal used in the liquid crystal display device is classified into a nematic liquid crystal having only the directional order and a smectic liquid crystal having both the directional order and the positional order depending on the molecular arrangement structure. The smectic liquid crystal can be further classified into a ferroelectric liquid crystal and a paraelectric liquid crystal depending on the presence or absence of spontaneous polarization. Nematic liquid crystals have no spontaneous polarization and are not affected by the polarity of the electric field. Nematic liquid crystals have dielectric anisotropy. Such a twisted nematic liquid crystal display device using a nematic liquid crystal is not suitable for a liquid crystal display device that requires a high-speed response because the response speed of liquid crystal molecules due to dielectric anisotropy is on the order of tens to hundreds of ms.
Furthermore, if multiple orientations and additional optical films are not used, the characteristics of a narrow viewing angle and a low contrast ratio are exhibited.

[0004] Compared to a nematic liquid crystal, a ferroelectric liquid crystal has a much higher response speed of molecules, about several tens of microseconds, due to a combination of spontaneous polarization and an electric field, and is suitable for realizing a high-speed moving image. However, the existing surface-stabilized ferroelectric liquid crystal display device operates in a bistable mode, cannot perform continuous gradation display, and it is extremely difficult to obtain a large-area uniform alignment. Recently, although a multi-gradation display function has been achieved by a time or space division driving method, a surface-stabilized ferroelectric liquid crystal display device can display only a very limited number of gradations due to a complicated driving mechanism. .

A recently introduced antiferroelectric liquid crystal display device has a quick response speed and a limited multi-gradation display function as compared with nematic, but still has a large area and uniform alignment. And the problem of screen flicker phenomenon. On the other hand, a helically deformed ferroelectric liquid crystal display device in which a ferroelectric liquid crystal has a very short helical pitch compared to the wavelength of incident light has been proposed. In such a liquid crystal display device, an electric field that intersects the electrodes on the two substrates is supplied so that the spiral structure of the substrate surface is deformed and continuous gradation display is achieved. Although this display device also has a high response speed, additional orientation steps such as deviation and electric field treatment are required to obtain a large-area uniform orientation. There is a further drawback such as the appearance of band tissue.

As described above, the conventional ferroelectric or antiferroelectric liquid crystal display device has disadvantages such as large-area uniform alignment, difficulty in analog gray scale display, and deterioration in image quality. Specifically, a ferroelectric or antiferroelectric liquid crystal has a short helical pitch, and a strong polar interaction between liquid crystal molecules and an alignment surface causes a defect structure such as a band structure to appear. It is extremely difficult to obtain an oriented structure. As described above, in a ferroelectric liquid crystal having a short pitch, a uniform structure reduces a contrast ratio, and it is impossible to obtain a high transmittance.

In order to realize a high-quality large-screen liquid crystal display device, excellent viewing angle characteristics are required in addition to a large-area uniform orientation, a high response speed, and a high contrast ratio. Liquid crystals are substances having extremely large optical anisotropy, and the effective refractive index greatly differs depending on the angle of light incident on liquid crystal molecules. At present, in the case of the twisted nematic mode, which is widely used, the change in the contrast ratio due to the change in the azimuth in the tilt direction about the axis perpendicular to the substrate surface appears very antisymmetrically. As a method for improving this, a light compensation method further using a uniaxial or biaxial retardation optical film under conditions for compensating the effective refractive index of the liquid crystal layer is widely used. As other methods, there are a method of using multiple alignment for two or four sub-pixels in which the alignment direction of liquid crystal is different for each pixel, and an in-substrate switching liquid crystal mode using molecular switching on the same substrate surface. .

[0008] Among the above-mentioned methods, in the case of the multiple alignment method, a multiple polishing or optical alignment technique is used at the time of manufacturing, and at least two or more mask processes are used, which complicates the process and degrades reliability. And the manufacturing cost is high. On the other hand, in the in-substrate switching mode, a nematic liquid crystal is currently employed, and the response speed is still low, and the transmittance is reduced due to a low aperture ratio and the image quality is reduced due to an afterimage. In addition, the liquid crystal itself is partially optically compensated for the viewing angle characteristics, and the optically compensated bending mode, and the reverse torsion nematic mode, which has a high contrast ratio and excellent viewing angle characteristics, are still known, but are still symmetric. It cannot have a wide viewing angle characteristic.

[0009]

[Problems to be solved by the invention]

The present invention has been made in order to solve the problems of the conventional technology, and an object of the present invention is to vertically align a ferroelectric liquid crystal having a helical pitch shorter than the wavelength of light between two substrates. By using an electric field parallel to the substrate and controlling the direction of molecular rotation by electrodes in the same substrate, a large area, uniform orientation, and a high contrast ratio,
It is an object of the present invention to provide a vertically aligned spirally deformed liquid crystal display device capable of continuously displaying gradation and obtaining a wide viewing angle.

[0010]

Means for Solving the Invention

In order to achieve the above-mentioned object of the present invention, the present invention comprises a first glass substrate having two surfaces facing each other and a second glass substrate formed on a first surface of the first glass substrate and having a first potential. A first transparent substrate formed on the first surface of the first glass substrate, the second transparent electrode having a second potential different from the first potential, and the first and second transparent electrodes; A first vertical alignment film formed on the first surface, a second vertical alignment film formed on the first surface of the second glass substrate, and first and second facing surfaces of the first and second vertical alignment films facing each other. Enclosed between glass substrates, having a helical pitch shorter than the wavelength of light, the helical structure is deformed in response to an electric field formed between the first and second transparent electrodes, and molecules rotate in a specific direction. Vertically oriented helical deformation liquid characterized by comprising a ferroelectric liquid crystal Crystal display device.

In the above apparatus, the transmission type has a first polarizing plate provided on the second surface of the first glass substrate and a polarizing plate provided on the second surface of the second glass substrate and having a polarizing property orthogonal to the first polarizing plate. Having a second
It further includes a polarizing plate.

In the above-mentioned apparatus, in the reflection type, a reflection plate is provided on the first surface or the second surface of the second glass substrate, and there is no polarizing plate on the second surface of the second glass substrate. A retardation film having an optical delay characteristic of / 4 is provided on the second surface of the first glass substrate, and a polarizing plate having an optical axis at 45 ° to the optical axis of the retardation film is further provided thereon.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings through a preferred embodiment of the present invention.

That is, in the present invention, the helical deformation phenomenon caused by application of an electric field to the ferroelectric liquid crystal is basically used as a driving principle. Unlike the existing spirally deformed ferroelectric liquid crystal display device, the spiral axis direction of the liquid crystal is oriented perpendicular to the substrate, and the transparent electrode exists only on one substrate surface. Therefore, a continuous gradation display function by applying an electric field within the same substrate can be easily achieved, and a high contrast ratio can be achieved by a large-area uniform vertical alignment without additional alignment steps such as polishing and electric field processing. can get. Further, two or four sub-pixels are formed for each pixel using a molecular rotation direction depending on the polarity of an electric field, and a wide viewing angle characteristic can be realized by a source-oriented multi-orientation structure.

FIG. 1 shows the configuration of a transmission type vertically aligned spirally deformed liquid crystal display device according to the present invention. In the liquid crystal display of the present invention, first and second transparent electrodes 20 and 30 made of indium tin oxide (ITO) are formed on the first surface 12 of the first glass substrate 10. As shown in FIG. 5 or FIG. 6, these two transparent electrodes are formed alternately, and the interval between the first and second transparent electrodes 20 and 30 is preferably maintained at about several tens to several hundreds μm. In this embodiment, the thickness is preferably 20 μm. Next, the first electrode on which the transparent electrodes 20 and 30 are formed is formed.
On the surface of the first surface 12 of the glass substrate 10, JALS-204 (Japan Synt
hetic Rubber Co. ) Is applied to form a first vertical alignment film 40. Further, JAL is applied to the surface of the first surface 52 of the second glass substrate 50.
The second vertical alignment film 60 is formed by applying a vertical alignment agent such as S-204 (Japan Synthetic Rubber Co.).

Next, the two glass substrates 10 and 50 face each other so as to face the first and second vertical alignment films 40 and 60. It is preferable that the distance between them is about several μm, preferably 5 μm. At this time, the product of the optical anisotropy of the liquid crystal and the distance between the two substrates is preferably smaller than 720 nm. Assuming that the surface inclination angle of the vertical alignment film with respect to the substrate surface is θs, 75 ° ≦ θs ≦ 90 ° is good, and in this embodiment, 90 ° is preferable. Further, FLC-10817 (Rolic LL) is provided between the two substrates 10 and 50.
td. ) Is poured and sealed. Here, the applied voltage of the ferroelectric liquid crystal decreases as the spontaneous polarization increases. In this embodiment, the spontaneous polarization is 11
A liquid crystal of 5 nC / cm ² is used. Further, the molecular tilt angle is preferably in the range of 22.5 ° ≦ θ ≦ 45 °, and in this embodiment, it is 34 °. Further, the helical pitch is preferably shorter than 0.35 μm for short wavelength visible light, and is set to 0.2 μm.

In order to obtain a uniform orientation, it is preferable that the smectic A phase exists in the phase transition order, but many substances having a large molecular tilt angle do not have the smectic A phase. Therefore, in the embodiment of the present invention, the isotropic phase- (64.5 ° -62.
(4 °) -chiral nematic phase- (62.4 ° -61.5 °) -chiral smectic C phase (ferroelectric phase).

In the case of the transmission type, a first polarizing plate 80 is provided on the second surface 14 of the first glass substrate 10, and a second polarizing plate 90 is provided on the second surface 54 of the second glass substrate 50. First polarizing plate 80
Of the electric field is 45 ° ± 3 ° with respect to the direction of the electric field parallel to the substrate. Further, the optical axis of the second polarizing plate 90 is set at 90 ° to the optical axis of the first polarizing plate 80.

The driving principle of the transmission type vertically aligned spirally deformed ferroelectric liquid crystal display device having the above-described configuration is as follows. When no electric field is applied in the vertical alignment structure, that is, in the case of the central pixel in FIGS. 1 and 2, the spiral structure of the liquid crystal smectic layer is maintained, and the average optical axis direction 71 is perpendicular to the substrate. In FIG. 2, one of the two substrates
The projected structure of the molecular arrangement of the central pixel shows that the molecules are arranged in all directions on the surface of the smectic cone. Therefore, two orthogonal polarizers 8
Light is completely blocked between 0 and 90.

On the other hand, when an electric field of a threshold value or more is applied to the liquid crystal display device, the average optical axis direction is inclined with respect to the substrate according to the polarity of the applied electric field that is directly connected to the spontaneous polarization of the ferroelectric liquid crystal. As a result, the incident light is transmitted through the polarizing plate that forms an angle of 45 ° with the direction of the electric field. In particular, in the left pixel, the liquid crystal molecules are arranged in the −90 ° direction, and the average optical axis direction 72 is inclined forward from the vertical direction. In the projected structure of the molecular arrangement of the left pixel in FIG. 2, it can be seen that the molecules are arranged only below. However, in the right pixel, the liquid crystal molecules are arranged in a 90 ° direction, so that the average optical axis direction 73 is inclined backward from the vertical direction. In FIG. 2, it can be seen that the molecules of the right pixel are arranged only above.

FIG. 3 shows the relationship between the electric field strength and the light transmission characteristics of the vertically aligned spirally deformed liquid crystal display according to the present invention. As shown, the helical structure is deformed while the liquid crystal molecules rotate continuously on the surface of the smectic cone due to the strength of the electric field, and the magnitude of the effective birefringence of the liquid crystal changes continuously. Therefore, the intensity of the light passing through the polarizing plate orthogonal to the direction of the electric field at an angle of 45 ° enables continuous gradation display by effective birefringence that changes continuously. That is, the intensity of the electric field parallel to the substrate is largest in the first glass substrate 10 having electrodes depending on the position, and is equal to the second glass substrate 5 having no electrodes.
The value gets smaller as going to zero. The molecular rotation angle is proportional to the strength of the electric field.

FIG. 4 shows the relationship between the square wave voltage waveform and the light transmission response characteristic of the vertically aligned spirally deformed liquid crystal display device according to the present invention. That is, it can be seen that the liquid crystal changes from the off state (light blocking state) to the on state (light transmitting state) from the off state (light blocking state) while exhibiting a response characteristic of approximately 140 μs when the rectangular wave is applied. Further, when the rectangular wave is cut off, it can be seen that the light transmittance changes from an on state (light transmitting state) to an off state (light blocking state) while exhibiting a response characteristic of approximately 40 μs when falling. Further, as can be seen from FIG. 3, the light transmittance in the ON state is proportional to the intensity of the applied electric field.

FIG. 5 shows a configuration of an embodiment of a drive electrode arrangement of a vertically-aligned spirally deformed liquid crystal display device according to the present invention. In one pixel, the first transparent electrode 20 has an n-shape, and the second transparent electrode 30 has an m-shape. The two electrodes 20 and 30 are arranged alternately. Therefore, four sub-pixels are arranged in a 1.times.4 form between these electrode branches. Therefore, in the pixel 100 in the ON state, four sub-pixels 101
, 102, 103, and 104, the directions of the electric fields applied thereto are alternately arranged, so that the average optical axis directions of the odd-numbered sub-pixels 101 and 103 and the even-numbered sub-pixels 102 and 104 have symmetry in opposite directions. Become like That is, a wide viewing angle can be secured by the anti-symmetric average optical axis direction of the plurality of sub-pixels in one pixel. Therefore, in the present invention, as compared with the conventional liquid crystal display device, a wide viewing angle can be easily secured by the configuration of the transparent electrode, and thus, an additional configuration such as an optical film is unnecessary.

FIG. 6 shows the configuration of another embodiment of the drive electrode arrangement of the vertically aligned spirally deformed liquid crystal display device according to the present invention. In another embodiment, the electrode structure includes a second transparent electrode 20 between two first transparent electrodes 20.
The transparent electrodes 30 are arranged, and a plurality of branches which are repeated vertically from the first transparent electrode 20 and a plurality of branches which are vertically extended from the second transparent electrode are alternately arranged. . Therefore, a pixel is divided into a plurality of sub-pixels by the branches of these electrodes, and two adjacent sub-pixels have optical axes opposite to each other along the horizontal direction. In such an electrode array structure, four sub-pixels have a 2 × 2 configuration.

FIG. 7 shows a configuration of a helical deformation liquid crystal display device of the reflection type vertical alignment according to the present invention. FIG. 7 shows the first surface 52 or the second surface 5 of the second glass substrate 50 as compared with the transmission type shown in FIG.
4, a reflecting plate 120 is provided, and the second surface 54 of the second glass substrate 50 has no polarizing plate.
The difference is that a retardation film 84 is provided between the first glass substrate 10 and the polarizing plate 80. Therefore, similar structures are processed with similar codes.

The optical axis direction of the retardation film 84 is configured to be 45 ° with respect to the optical axis direction of the polarizing plate 80. The phase difference film 84 has a phase delay of 1/4 of the wavelength of the incident light. The retardation of the retardation film 84 is 160 × Nnm and 200 × Nnm (N = 1
, 2, 3,...). In the reflection type, when no electric field is applied, the average optical axis of the liquid crystal is perpendicular to the substrate, and the optical characteristics are determined by the phase delay of the retardation film. The effective phase difference of the light is 2 of the phase delay of the phase difference plate 84.
A dark state that is twice as high is realized. When an electric field is applied to the reflective liquid crystal display device, the average optical axis of the liquid crystal is inclined from the surface in the direction perpendicular to the substrate due to the effective birefringence.
Therefore, the bright state is realized by the phase delay based on the product of the effective birefringence and the distance between the two substrates.

[0027]

【The invention's effect】

As described above, according to the present invention, a large-area uniform orientation and a continuous gradation display function can be easily solved, and a high contrast ratio by vertical orientation can be obtained. Furthermore, a source-side multi-region structure is possible by designing the electrode array structure, and a wide viewing angle characteristic can be obtained. In addition, there is an advantage that an alignment film surface treatment step such as polishing is not required, the manufacturing process is simple, and the manufacturing cost is reduced.

While the above description has been made with reference to preferred embodiments of the present invention, those skilled in the art will appreciate that the present invention can be practiced without departing from the spirit and scope of the invention as set forth in the appended claims. Can be variously modified and varied.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a transmission type vertically aligned spirally deformed liquid crystal display device according to the present invention.

FIG. 2 is a diagram for explaining the operation principle of FIG. 1;

FIG. 3 is a graph showing a relationship between an electric field strength and a light transmission characteristic of a vertically aligned spirally deformed liquid crystal display device according to the present invention.

FIG. 4 is a graph showing a relationship between a rectangular wave voltage waveform and a light transmission response characteristic of a vertically aligned spirally deformed liquid crystal display device according to the present invention.

FIG. 5 is a view showing a configuration of an embodiment of a drive electrode arrangement of a vertically-oriented spirally deformed liquid crystal display device according to the present invention.

FIG. 6 is a view showing a configuration of another embodiment of a drive electrode arrangement of a vertically aligned spirally deformed liquid crystal display device according to the present invention.

FIG. 7 is a view illustrating a configuration of a reflective vertical alignment spirally deformed liquid crystal display device according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 first glass substrate 20 first transparent electrode 30 second transparent electrode 40 first vertical alignment film 50 second glass substrate 60 second vertical alignment film 70 ferroelectric liquid crystal 80 first polarizing plate 82 reflecting plate 84 retardation film 90 Second polarizing plate 100 pixels (ON) 110 pixels (OFF) 101-104 Sub-pixel 120 Reflector

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GD, GE , GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, U S, UZ, VN, YU, ZA, ZWF terms (reference) 2H049 BA02 BA07 BB03 BC22 2H088 EA02 GA04 HA02 HA06 JA17 KA17 MA13 MA18 2H090 HB01Y HC05 HD14 HD18 KA14 LA01 MA01 MA11 2H092 GA05 GA14 NA04 PA02 QA13 It has excellent viewing angle characteristics.

Claims (10)

[Claims] A first glass substrate having two surfaces facing each other; a first transparent electrode formed on a first surface of the first glass substrate and having a first potential; A second transparent electrode formed on the first surface of the glass substrate and having a second potential different from the first potential; and a second transparent electrode formed on the first surface of the first glass substrate on which the first and second transparent electrodes are formed. A first vertical alignment film to be formed, a second vertical alignment film formed on the first surface of the second glass substrate, and a first vertical alignment film between the first and second glass substrates facing each other. Encapsulation, having a helical pitch even shorter than the wavelength of light,
A vertically aligned spirally deformed ferroelectric liquid crystal display device comprising a ferroelectric liquid crystal that undergoes a spiral deformation in response to an electric field formed between transparent electrodes and molecules rotate in a specific direction. 2. The ferroelectric liquid crystal according to claim 1, wherein the molecular tilt angle is 22.5 ° ≦ θ ≦ 45 °, where θ is the molecular tilt angle with respect to the helical axis. Spiral deformation ferroelectric liquid crystal display device with vertical alignment. 3. The vertically aligned spirally deformed ferroelectric liquid crystal display device according to claim 1, wherein a spiral pitch of the ferroelectric liquid crystal is shorter than 0.35 μm. 4. The vertically aligned spirally deformed ferroelectric liquid crystal display device according to claim 1, wherein 75 ° ≦ θs ≦ 90 ° where a surface inclination angle of the vertical alignment film with respect to the substrate surface is θs. . 5. The vertically aligned spirally deformed ferroelectric liquid crystal display according to claim 1, wherein the product of the refractive index anisotropy of the ferroelectric liquid crystal and the distance between the substrates is smaller than 720 nm. apparatus. 6. The apparatus according to claim 1, further comprising a first polarizing plate provided on a second surface of the first glass substrate, and a polarizing plate provided on a second surface of the second glass substrate, the polarizing plate being orthogonal to the first polarizing plate. The vertically aligned helically deformed ferroelectric liquid crystal display device according to claim 1, further comprising a second polarizing plate having a property. 7. The optical system according to claim 6, wherein the first polarizing plate has an optical axis direction of approximately 45 ° with respect to a direction of an electric field formed between the first and second transparent electrodes. A vertically aligned spirally deformed ferroelectric liquid crystal display device as described in the above. 8. The method according to claim 1, wherein the first transparent electrodes and the second transparent electrodes are alternately arranged so that the average optical axes of two adjacent left and right pixels are antisymmetric with each other. 5. A vertically aligned spirally deformed ferroelectric liquid crystal display device according to item 1. 9. A first and second glass substrate each having two surfaces facing each other, a first transparent electrode formed on a first surface of the first glass substrate and having a first potential, and A second transparent electrode formed on a first surface of the glass substrate and having the first potential and another second potential; and a second transparent electrode formed on the first surface of the first glass substrate on which the first and second transparent electrodes are formed. A first vertical alignment film to be formed; a reflector provided on one side surface of the second glass substrate; a second vertical alignment film formed on a first surface of the first glass substrate; A retardation film having an optical delay characteristic of 1/4 of the wavelength of light on a second surface of the substrate; and a retardation film provided on the second surface of the first glass substrate and having an angle of 45 ° with the optical axis of the retardation film.
A polarizing plate having an optical axis, and the first and second vertical alignment films are sealed between first and second glass substrates facing each other, have a helical pitch shorter than the wavelength of light, and A vertically aligned helically deformed ferroelectric liquid crystal display device comprising a ferroelectric liquid crystal that is helically deformed in response to an electric field formed between the second transparent electrodes and has molecules rotated in a specific direction. . 10. The retardation film having a retardation of 160 × Nnm and 200
The vertically aligned spirally deformed ferroelectric liquid crystal display device according to claim 9, wherein the liquid crystal display device has a value between × Nnm (N = 1, 2, 3,...).