JPH09197424A - Liquid crystal element and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to suppress the flickering of a screen in multiplex- driving. SOLUTION: An alignment layer is formed stop transparent electrodes 2 and metallic electrodes 3. The alignment layer is subjected to a uniaxial alignment layer treatment, by which liquid crystals are oriented. In the case of this uniaxial alignment layer treatment, the angles formed by the respective sides 61a, 62a which exist on upward side in an uniaxial alignment layer treatment direction among the longitudinal direction sides 61, 61a and transverse sides 62, 62a of the pixels 6A formed of the metallic electrodes 3 are set at the angles at which the smaller of the angles formed by the respective sides 61a, 62a and the uniaxial alignment layer treatment direction R2 attains <=30 deg., by which the abnormal inversion phenomena occurring on the respective sides 61a, 61a in multiplex-driving are decreased and the flixkering arising on the screen is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal element using a chiral smectic liquid crystal, and more particularly to a liquid crystal element capable of suppressing flicker on the screen during multiplexing driving and a method for manufacturing the same.

[0002]

2. Description of the Related Art A liquid crystal device of a type in which a transmitted light is controlled by a combination of a chiral smectic liquid crystal having a refractive index anisotropy and a polarizing device has been proposed by Clark and Lagerwall. 56-107216, U.S. Pat. No. 43.
67924, etc.).

Here, this chiral smectic liquid crystal generally has a chiral smectic C phase (SmC *) or H phase (SmH *) in a specific temperature range. In this state, the first chiral smectic liquid crystal responds to an applied electric field. Has an optical stable state and a second optical stable state, and has the property of maintaining that state when no electric field is applied, that is, bistability, and responds quickly to changes in the electric field. Therefore, it is expected to be widely used as a high-speed and memory type display element.

By the way, the liquid crystal element using the chiral smectic liquid crystal has a matrix electrode composed of scan electrodes and signal electrodes for performing multiplexing drive, and a scan signal is sequentially applied to the scan electrodes. On the other hand, the information signal is applied to the signal electrode in synchronization with the scanning signal.

Further, in such a liquid crystal element, since the element itself has a memory effect, the driving wiring can be a simple matrix wiring even in the case of driving with a high duty ratio. This means that each pixel has a switching element. Compared with the liquid crystal device of the system, it is advantageous in improving the display density and reducing the production cost.

[0006]

However, in such a conventional liquid crystal element, the liquid crystal element is driven by multiplexing driving, and the driving method is refresh driving in which scanning signals are repeatedly and periodically applied to the scanning electrodes. In this case, there is a problem in that the brightness of a large number of pixels that form the screen changes periodically, which causes the brightness of the entire screen to change periodically, causing flickering on the display screen.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal element capable of suppressing the flickering of the screen during multiplexing driving and a method of manufacturing the same. It is a thing.

[0008]

According to the present invention, a liquid crystal is arranged between a pair of substrates which are arranged to face each other, and a transparent electrode for applying a voltage to the liquid crystal is formed on each of the facing surfaces of the substrate. In the liquid crystal element, a metal electrode that is formed on the upper surface of the transparent electrode and defines a number of pixels that form a screen, and a uniaxial film that is formed on the upper surfaces of the transparent electrode and the metal electrode and that aligns the liquid crystal. An alignment film that is subjected to directional processing, and an angle formed by each side that is a good side in the uniaxial alignment processing direction of the vertical side and the horizontal side of the pixel formed by the metal electrode is It is characterized in that a smaller one of angles formed by each side and the uniaxial orientation processing direction is set to be a predetermined angle or less so as to suppress an abnormal reversal phenomenon occurring on each side during driving. Also It is.

Further, the present invention is characterized in that an angle formed by each of the sides on the good side is a sum of two angles equal to or less than a predetermined angle formed by each of the sides and the uniaxial orientation treatment direction. It is a thing.

Further, according to the present invention, at least one of the two sides on the upper side in the uniaxial orientation processing direction has a sawtooth shape, and the sawtooth angle is one of the angles formed by the sawtooth shaped side and the uniaxial orientation processing direction. It is characterized in that the smaller one is set to an angle equal to or smaller than a predetermined angle.

The present invention is also characterized in that the predetermined angle is 30 °.

According to the present invention, the liquid crystal is at least 2
It is characterized by being a chiral smectic liquid crystal exhibiting two optically stable states.

Further, the present invention is characterized in that a matrix electrode is formed by arranging the pair of substrates so as to face each other in a direction in which the transparent electrodes are orthogonal to each other, thereby enabling multiplexing driving.

Further, according to the present invention, liquid crystal is arranged between a pair of substrates facing each other, and a transparent electrode for applying a voltage to the liquid crystal is formed on each of the facing surfaces of the substrates. In the manufacturing method of 1., a metal electrode that defines a large number of pixels forming a screen is formed on the upper surface of the transparent electrode, and a uniaxial alignment treatment for aligning the liquid crystal is performed on the upper surfaces of the transparent electrode and the metal electrode. While forming an alignment film formed on the metal electrode, the angle formed by each side on the upper side in the uniaxial alignment processing direction of the vertical side and the horizontal side of the pixel formed by the metal electrode is defined as the respective side. A smaller one of the angles formed with the uniaxial orientation processing direction is set to be an angle equal to or smaller than a predetermined angle, and an abnormal reversal phenomenon occurring on each side during driving is suppressed. It is.

Further, according to the present invention, at least one of the two sides on the upper side in the uniaxial orientation processing direction has a sawtooth shape, and the angle of the sawtooth is one of angles formed by the sawtooth shaped side and the axial orientation processing direction. It is characterized in that the smaller one is set to an angle equal to or smaller than a predetermined angle.

Further, the present invention is characterized in that the predetermined angle is 30 °.

According to the present invention, the liquid crystal is at least 2
It is characterized by being a chiral smectic liquid crystal exhibiting two optically stable states.

Further, the present invention is characterized in that a matrix electrode is formed by arranging the pair of substrates so as to face each other in a direction in which the transparent electrodes are orthogonal to each other, thereby enabling multiplexing driving.

Further, with this structure, a voltage can be applied to the liquid crystal disposed between the pair of substrates which are arranged to face each other by the transparent electrodes formed on the facing surfaces of the substrates. A large number of pixels forming a screen can be defined by the metal electrode formed on the upper surface of the transparent electrode. In addition, an alignment film is formed on the upper surfaces of the transparent electrode and the metal electrode, and the alignment film is subjected to a uniaxial alignment treatment to align the liquid crystal. Then, in this uniaxial alignment treatment, the angle formed by each of the vertical sides and the horizontal sides of the pixel formed by the metal electrode, which is the better side in the uniaxial alignment treatment direction, is defined as the respective uniaxial alignment treatment. By setting the angle that the smaller one of the direction and the direction becomes 30 ° or less, during multiplexing driving,
Abnormal inversion phenomenon that occurs on each side is suppressed, and flicker that occurs on the screen is suppressed. Further, at least one of the two sides on the upper side with respect to the axial orientation processing direction is formed into a sawtooth shape, and the angle of the sawtooth is smaller than 30 ° among the angles formed by the sawtooth side and the axial orientation processing direction. By setting the angle, when multiplexing driving,
Try to reduce the flicker that occurs on the screen.

Further, in the method of manufacturing a liquid crystal element, a uniaxial film is formed on the upper surface of the transparent electrode to form a metal electrode defining a large number of pixels constituting a screen and to align the liquid crystal on the upper surfaces of the transparent electrode and the metal electrode. An alignment film to be subjected to alignment treatment is formed. Then, of the vertical side and the horizontal side of the pixel formed by the metal electrode, the angle formed by each side on the upper side in the uniaxial alignment processing direction is smaller than the angle formed by each side and the uniaxial alignment processing direction. By setting the angle such that the angle becomes 30 ° or less, the abnormal inversion phenomenon occurring on each side during multiplexing driving is suppressed,
A liquid crystal element capable of suppressing flickering on the screen is manufactured.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial side sectional view of a liquid crystal element using a chiral smectic liquid crystal according to the present invention, and FIG. 2 is a plan view of this liquid crystal element when viewed from the user side.

In FIGS. 1 and 2, 1A is a liquid crystal element, 1 is one of a pair of substrates made of glass, plastic or the like which are arranged to face each other so as to form a cell of the liquid crystal element 1A, and 2 is a substrate. Transparent electrodes made of ITO etc., 3
Is a metal electrode formed of a metal such as aluminum, chromium or molybdenum or an alloy thereof. The transparent electrode 2
Is 300Å to 5000Å (preferably 500Å to 200)
It has a thickness of 0Å), and the metal electrode 3 is 300Å
It is provided with a film thickness of up to 5000 Å (preferably 500 Å to 3000 Å).

Reference numeral 4 is an insulating film provided to prevent a short circuit between the transparent electrode 2 and the metal electrode 3 and an electrode provided on the other substrate 1a described later, and 5 is provided on the insulating film 4. It is a prepared alignment film. A SiO ₂ film, a TiO ₂ film or the like is used as the insulating film 4, and a polyvinyl alcohol film, a polyimide film, a polyamide film, a polyester film, a polyamideimide film or a polyesterimide film is used as the alignment film 5. There is.

2, reference numerals 6, 6, ... Represent a large number of pixels constituting the screen, and the transparent electrode 2 is formed by the pixels 6, 6.
6 ・ ・ ・, and for example horizontal pixels 6, 6, ...
Are formed in stripes along each horizontal pixel row 6A. The pixels 6, 6, ... Are defined by the metal electrode 3.

On the other hand, FIG. 3 shows one substrate 1 of the liquid crystal element 1A.
FIG. 2 is a plan view of the other substrate (the substrate on the back side as viewed from the user) provided so as to face the substrate, in which FIG.
The other substrate 2a of the liquid crystal element 1A made of plastic or the like is a transparent electrode made of ITO or the like.
0Å ~ 5000Å (preferably 500Å ~ 2000Å)
It is provided with a film thickness of.

The substrate 1 shown in FIGS.
When the liquid crystal is assembled, reference numeral 1a indicates AC and B- as shown in FIG.
D and D are arranged so as to face each other. Then, in this direction, the two substrates 1,
By arranging 1a to face each other, the transparent electrode 2 (and the metal electrode 3) on one substrate 1 and the transparent electrode 2a on the other substrate 1a cross each other, and as shown in FIG. 30 is formed.

By the way, the two arrows R4 and R shown in FIG.
Reference numeral 5 indicates the direction of a uniaxial orientation treatment axis such as a rubbing treatment axis applied to each of the substrates 1 and 1a, that is, the rubbing direction. Then, when the substrates 1 and 1a are assembled, the direction R4 (R5) of the rubbing treatment axis is set at a predetermined angle with the horizontal line R0 directed to the left side of the substrate 1 as seen from the user side as shown in FIG. (60 ° in the figure).

Here, in the driving of the liquid crystal element thus constructed, as described above, the scanning signal is applied to the scanning electrodes of the matrix electrode 30, and the information signal is applied to the signal electrodes in synchronization with the scanning signal. Yes Multiplexing drive is used. In the present embodiment, the scanning electrodes are the transparent electrodes 2 and the metal electrodes 3 on one substrate 1, and the scanning signals shown in (1) of FIG. Transparent electrode 2a on the other substrate 1a
Is used as a signal electrode, and an information signal as shown in (2) of the figure is applied to the transparent electrode 2a.

By the way, when the liquid crystal element 1A is driven by the matrix electrode 30 having such a structure, the abnormal inversion phenomenon of the domain starts to occur from the peripheral portion of the pixel 6 soon. Here, this abnormal inversion phenomenon changes depending on the pulse width (3ΔT) of the information signal and the rubbing direction. For example, the pulse width of the information signal is 52.0 μsec,
When the rubbing direction is changed from 5 ° to 62.0 μsec and the rubbing direction is changed from 0 ° to 90 ° with respect to the lateral side 62 of the pixel 6, the state of the abnormal inversion phenomenon occurring in the pixel 6 is (2) in FIG. It becomes like the sketch of the 200 times micrograph shown in. In addition, the measurement temperature in this experiment is 30 ° C. in all cases.

Here, as is apparent from FIG. 7B, it is the abnormal inversion phenomenon of the domain 81 that causes the periodic flicker, and the domain 81 has a pixel 6 in which a scanning signal is applied. As shown in the same figure, the metal electrode 3 in the peripheral portion of the pixel 6 is affected by the electric field of the information signal to which the white signal or the black signal waveform is constantly applied from the time the signal is input until the selection signal of the next frame is input. Is generated from the edge portion of, and the area is extended in a chain along the rubbing direction.

Further, the domain 81 is on the better side in the rubbing direction shown by the arrow in FIG. 7A and the rubbing direction of the vertical sides 61, 61a and the horizontal sides 62, 62a forming the pixel 6. Sides 61a, 62a
The drive pulse width at the start of generation and the degree of growth change depending on the angle of intersection with.

That is, for example, when the rubbing direction is 0 °, an abnormal reversal phenomenon is almost generated in the lateral side 62a, 62a parallel to the rubbing direction, which is the upper side (hereinafter referred to as the upper lateral side) 62a. However, the abnormal reversal phenomenon occurs in large quantities on the vertical side on the upper side (hereinafter referred to as the vertical side on the upper side) 61a of the vertical sides 61 and 61a perpendicular to the rubbing direction.

That is, the abnormal reversal phenomenon extends in the same direction as the rubbing direction from the upper side to the lower side in the rubbing direction, but the occurrence thereof is the angle formed by the rubbing direction and the vertical side 61a on the upper side and the lateral side 62a on the upper side. Are smaller as they are closer to parallel, and larger as the angles are closer to vertical.

On the other hand, FIG. 8 shows the driving pulse width in which the abnormal inversion phenomenon and the visual flicker of the element were observed in each rubbing direction of this experiment. In FIG. 8, the first driving pulse width was observed under a microscope. Is the drive pulse width at which the abnormal inversion phenomenon starts to occur from the upper side 61a of the pixel 6, and the second drive pulse width is the drive pulse width at which the abnormal inversion phenomenon starts to occur from the upper side 62a of the pixel 6. The third drive pulse width shows the drive pulse width in which flicker is recognized from the screen by visual observation. FIG.
Further, the angle shown in FIG. 8 shows the angle formed by the upper lateral side 62a and the rubbing direction, and the angle formed by the upper vertical side 61a and the rubbing direction is a complementary angle.

As is clear from FIGS. 7 and 8, the drive pulse width at which the abnormal inversion phenomenon starts to occur from the vertical side 61a on the upper side is the angle formed by the horizontal side 62a on the upper side and the rubbing direction (hereinafter referred to as crossing). The angle becomes larger as the angle becomes larger, but when the intersection angle becomes 60 ° or more, the rate of change becomes smaller.

Therefore, in order to suppress the abnormal reversal phenomenon from the vertical side 61a on the good side, the crossing angle is 90 °.
60 ° or more, in other words, 61 on the good side vertical side
The angle between a and the rubbing direction may be 30 ° or less.

On the other hand, the drive pulse width at which the abnormal reversal phenomenon starts to occur from the right side 62a becomes smaller as the crossing angle becomes smaller, but the change rate becomes smaller when the angle becomes 30 ° or less. Therefore, in order to suppress the abnormal reversal phenomenon from the good lateral side 62a, the intersection angle may be set to 30 ° or less instead of 0 °.

From this, it can be understood that the angle formed by the respective sides 61a, 62a on the upper hand side and the rubbing direction should be 30 ° or less in order to improve the occurrence of the flicker phenomenon. However, in the normal pixel 6 in which the intersecting angles of the respective sides 61a and 62a on the right side are 90 °, when the angle formed by one side and the rubbing direction is 30 ° or less, the other side is a complementary angle to 90 °. Therefore, the occurrence of abnormal reversal on the other side becomes large, and the flicker phenomenon cannot be alleviated only by changing the rubbing direction.

Therefore, in the present embodiment, the angle formed by the rubbing direction and each side 61a, 62a on the good side can be set to a predetermined angle of 30 ° or less, for example, as shown in FIG. Side vertical side 61a and good side horizontal side 62
Pixels 6A having an acute angle with a are formed. In the figure, R1 indicates the rubbing direction, and 11 and 12 indicate abnormal reversal portions (in this case, black reversal areas for white writing).

By the way, in the figure, each side 61 on the good side
The angle formed by the a and 62a and the rubbing direction is 25 °, but in this case, the angle formed by the vertical side 61a on the upper hand side and the horizontal side 62a on the upper hand side is twice that angle, which is 50 °. That is, the angle formed by each side 61a, 62a on the good side is
The relationship is the sum of the angles formed by the respective sides 61a, 62a on the good side and the rubbing direction.

On the other hand, FIG. 10 shows each side 6 on the good side.
It is a figure which shows the rubbing direction at the time of forming the liquid crystal element provided with the deformation kite type pixel 6A in which the angle formed by 1a and 62a is an acute angle. The rubbing direction in this case is set to 60 ° for the following reason.

That is, in general, the viewing angle characteristic of a liquid crystal element that obtains a display function by sandwiching a liquid crystal between crossed Nicols has a minimum display contrast in the direction of 45 ° with respect to the absorption axes of both the polarizer and the analyzer. In this case, the display quality deteriorates. On the other hand, a liquid crystal element using a chiral smectic liquid crystal obtains a display function by making the absorption axis of an analyzer coincide with the molecular axis of one of the two stable states of the chiral smectic liquid crystal. In order to make the direction of the minimum contrast the vertical direction of the screen, which has the least effect in practical use as a display element, the opening angle between the two stable states of the chiral smectic liquid crystal is 11 °.
If it is about 15 °, the rubbing angle is about 56 ° -6.
It is necessary to set it to about 0 °. Therefore, the rubbing axis direction R1 is set to 60 °.

Then, the rubbing direction is 60 ° in this way.
When the pixel 6A of the liquid crystal element 1A rubbed in the above manner is observed under a microscope and the multiplex drive is performed with the same drive waveform as that shown in FIG. 6, a drive pulse causing an abnormal inversion phenomenon from each side 61a, 62a on the good side. The width was as shown in FIG.

In the figure, the fourth drive pulse width shows that the abnormal inversion phenomenon is observed in the pixel 6A shown in FIG.
The drive pulse width that starts to occur from the upper vertical side 61a is
The fifth drive pulse width indicates the drive pulse width at which the abnormal inversion phenomenon starts to occur from the lateral side 62a on the upper hand side shown in FIG. 10, and the sixth drive pulse width indicates the drive pulse width at which flicker is recognized by visual observation. ing.

Here, the fourth drive pulse width is 61.7 μs.
ec, on the other hand, the drive pulse width at which the abnormal inversion phenomenon starts to occur from the vertical side 61a on the upper side of the conventional square pixel 6 calculated based on the data of FIG. 8 is 55.0 μsec. The pulse width in which the abnormal inversion phenomenon occurs in the modified kite type pixel 6A is improved by 10% or more as compared with the conventional square pixel 6.

The fifth drive pulse width is 60.9 μse.
On the other hand, the drive pulse width at which the abnormal inversion phenomenon starts to occur from the side 62a on the upper side of the conventional square pixel 6 obtained by calculation based on FIG. 8 is 55.0 μsec.
Which is improved by 10% or more.

As described above, by forming the modified kite type pixel 6A by setting the respective sides 61a, 62a on the right side to intersect with the rubbing direction at an angle of 30 ° or less, compared to the conventional square pixel 6. The drive pulse width at which the abnormal inversion phenomenon starts to occur can be improved, and the occurrence of the abnormal inversion phenomenon can be suppressed.

As a result, the pulse width causing visual flicker caused by abnormal reversal of the respective sides 61a and 62a on the right side is 67.6 μsec as shown in FIG. 11, which is the maximum in the conventional square pixel 6 shown in FIG. Pulse width 6
It can be improved from 3.5 μsec, and screen flicker can be suppressed.

Next, a method of manufacturing the liquid crystal element having such a structure will be described with reference to FIGS.

First, two 1.1 mm thick glass substrates 1 and 1a are prepared, and ITO is formed on each of the substrates 1 and 1a.
The striped transparent electrode 2 is formed. Next, a metal electrode 3 made of molybdenum is vapor-deposited and formed on the transparent electrode 2 of the one substrate 1 to a thickness of 1500 Å, and thereafter, the shape of the opening of the pixel 6A becomes a modified kite type as shown in FIG. The metal electrode 3 is etched.

Next, SiO ₂ is formed as an insulating film 4 on the surface of the metal electrode 3 by a sputtering method, and then an aminosilane 0.1% IPA (isopropyl alcohol) solution is applied on the insulating film 4 at a rotation speed of 2000 rpm. After being applied with a spinner for 15 seconds and baked at 150 ° C., a 2% solution of polyimide forming liquid SP510 (manufactured by Toray) (NMP: n-butyl cellosolve = 2: 1) is applied with a spinner having a rotation speed of 3000 rpm for 30 seconds. After that, a heat treatment at 300 ° C. is performed for about 1 hour to form a polyimide alignment film 5 having a film thickness of 200 Å.

Next, the polyimide alignment film 5 on one substrate 1
On the other hand, the direction of R2 shown in FIG. 10, that is, the rubbing angle is 60 °, and the upper side 62a and the upper side 61a are
The rubbing treatment is performed at an angle of 25 °, and the rubbing treatment is performed on the other substrate 1a in a direction in which the rubbing axis directions are parallel to each other when facing the substrate 1.

Thereafter, SiO _{2 having} an average particle size of about 1.5 μm
After applying the beads to one of the substrates 1, the rubbing treatment axes and the directions thereof should be parallel rubbing.
The two substrates 1 and 1a are bonded together to form a cell.

Finally, "CS-1014" (trade name) manufactured by Chisso Corporation was vacuum-injected into this cell under an isotropic phase, and then gradually increased from the isotropic phase to 60 ° C at 0.5 ° C / m. The liquid crystal element is formed by orienting the chiral smectic liquid crystal by cooling.

By the way, as described above, each side 61 on the good side
Although the flicker can be improved by setting the angle between a and 62a and the rubbing direction to about 30 ° or less, the aperture ratio becomes low in the modified kite type pixel 6A as shown in FIG.

Therefore, for example, as shown in FIG. 12, at least one of the upper sides 61a and 62a of the pixel 6B, that is, the upper side 62a in the present embodiment, has a sawtooth shape and the sawtooth angle is a sawtooth shape. Each part of the side of 621,62
The smaller of the angles formed by 2, 623 and the rubbing direction is 25 °, which is 30 ° or less, and in the figure, it is 50 ° to increase the aperture ratio.

FIG. 13 shows the ratio of the aperture ratios of the pixel 6B whose outer shape is changed as described above and the modified kite type pixel 6A. As shown in FIG. 13, the aperture of the sawtooth pixel 6B is shown. The ratio is 68.% against 100% of the conventional square pixel 6.
6% and about 70% can be secured, and the modified kite type pixel 6A
Is 49.5% with respect to the square pixel 6, the aperture ratio is significantly improved.

By the way, the pixel 6B having such a shape
When the pixel is driven, the sides 61a and 62a on the right side are
The drive pulse width for the occurrence of the abnormal reversal phenomenon is shown in FIG. Here, in the figure, the seventh drive pulse width is the drive pulse width at which the abnormal inversion phenomenon starts to occur from the upper vertical side 61a of the pixel 6B in FIG. 12 under the microscope observation, and the eighth drive pulse width is the abnormal inversion phenomenon. Is 6 on the right side of Fig. 12.
The drive pulse width starting from 2a and the ninth drive pulse width show the drive pulse width in which flicker is recognized from the element by visual observation.

Here, the seventh drive pulse width is 60.5 μs.
On the other hand, the drive pulse width of the conventional square pixel 6 obtained by calculation based on FIG.
It is 5.0 μsec, which is improved by 10%. Also,
While the eighth drive pulse width is 59.9 μsec,
The drive pulse width of the conventional square pixel 6 obtained based on FIG. 8 is 54.9 μsec, which is improved by 10% or more.

As described above, by setting the respective sides 61a, 62a on the right side to intersect with the rubbing direction at an angle of 30 ° or less, the drive pulse in which the abnormal inversion phenomenon starts to occur as compared with the conventional square pixel 6. The width can be improved, and the occurrence of abnormal reversal can be suppressed.

As a result, the pulse width at which flicker by visual observation caused by abnormal inversion of the respective sides 61a, 62a on the right side occurs is 66.7 μsec as shown in FIG. 14, which is the maximum in the conventional square pixel 6 shown in FIG. Pulse width 6
It can be improved from 3.5 μsec, and screen flicker can be suppressed.

[0063]

As described above, according to the present invention,
Of the vertical side and the horizontal side of the pixel, the angle formed by each side on the better side in the uniaxial orientation processing direction is smaller than the angle formed by each side and the uniaxial orientation processing direction.
By setting the angle to be 0 ° or less, it is possible to suppress the abnormal inversion phenomenon occurring on each side during multiplexing driving. As a result, it is possible to prevent the flickering of the screen caused by the periodical change in the brightness of the pixel, and to form a screen with high display quality.

[Brief description of drawings]

FIG. 1 is a partial side sectional view of a liquid crystal element using a chiral smectic liquid crystal according to the present invention.

FIG. 2 is a plan view of the liquid crystal element when viewed from the user side.

FIG. 3 is a plan view of a substrate on the back side when viewed from the user of the liquid crystal element.

FIG. 4 is a view showing an assembling direction of a substrate at the time of manufacturing a liquid crystal element.

FIG. 5 is a view showing a state in which matrix electrodes of the liquid crystal element are formed corresponding to pixels.

FIG. 6 is a waveform diagram showing an example of a scanning signal and an information signal applied to the matrix electrode.

FIG. 7 is a diagram showing how the occurrence state of the abnormal reversal phenomenon changes according to the rubbing direction and the drive pulse width.

FIG. 8 is a chart showing respective drive pulse widths at which abnormal inversion phenomenon at each rubbing angle and visual flicker of a liquid crystal element are observed.

FIG. 9 is a diagram showing an example of a pixel shape of a liquid crystal element according to an embodiment of the present invention.

FIG. 10 is a diagram showing a rubbing direction applied when forming the liquid crystal element.

FIG. 11 is a chart showing each drive pulse width in which abnormal reversal phenomenon in a pixel having the above-described shape and flicker by visual observation of a liquid crystal element are observed.

FIG. 12 is a diagram showing another example of the shape of the pixel of the liquid crystal element according to the embodiment of the invention.

FIG. 13 is an abnormal inversion phenomenon in a pixel having another shape,
The chart which shows each drive pulse width in which the flicker by the visual observation of the liquid crystal element was observed.

FIG. 14 is a chart showing the ratio of the aperture ratio of a pixel of the above two shapes to that of a conventional pixel.

[Explanation of symbols]

 1, 1a Substrate 1A Liquid crystal element 2, 2a Transparent electrode 3 Metal electrode 4 Alignment film 6, 6A, 6B Pixel 30 Matrix electrode 61a Upper vertical side 62a Upper horizontal R1, R4, R5 Rubbing direction

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Moriyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masanobu Asaoka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Yasushi Asao 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Ikuo Nakazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] 1. A liquid crystal device comprising: a pair of substrates which are arranged to face each other; and a liquid crystal disposed between the pair of substrates, and a transparent electrode for applying a voltage to the liquid crystal is formed on each of the facing surfaces of the substrate. A metal electrode formed on the upper surface of the electrode to define a large number of pixels forming a screen, and an alignment film formed on the upper surfaces of the transparent electrode and the metal electrode and subjected to uniaxial processing for aligning the liquid crystal. And the angle formed by each of the vertical sides and the horizontal sides of the pixel formed of the metal electrode, which is the better side in the uniaxial alignment treatment direction, is defined by the respective sides and the uniaxial alignment treatment. A liquid crystal element characterized in that a smaller one of the angles formed with the direction is set to be equal to or smaller than a predetermined angle so as to suppress an abnormal inversion phenomenon occurring on each of the sides during driving. 2. The angle formed by each of the sides on the good side is the sum of two predetermined angles or less formed by the respective sides and the uniaxial orientation processing direction. The liquid crystal element described. 3. At least one of the two sides on the upper side in the uniaxial orientation processing direction has a sawtooth shape, and the angle of the sawtooth is smaller than the angle formed between the sawtooth side and the uniaxial orientation processing direction. 2. The liquid crystal element according to claim 1, wherein the angle is set to be a predetermined angle or less. 4. The liquid crystal device according to claim 1, wherein the predetermined angle is 30 °. 5. The liquid crystal device according to claim 1, wherein the liquid crystal is a chiral smectic liquid crystal exhibiting at least two optically stable states. 6. The liquid crystal element according to claim 1, wherein a matrix electrode is formed by arranging the pair of substrates so as to face each other in a direction in which the transparent electrodes are orthogonal to each other, thereby enabling multiplexing driving. 7. A method of manufacturing a liquid crystal device, wherein liquid crystal is arranged between a pair of substrates which are arranged to face each other, and transparent electrodes for applying a voltage to the liquid crystal are formed on the opposite surfaces of the substrates, respectively. In, the metal electrode defining a large number of pixels forming a screen is formed on the upper surface of the transparent electrode, and the uniaxial alignment treatment for aligning the liquid crystal is performed on the upper surfaces of the transparent electrode and the metal electrode. While forming a film, the angle formed by each side of the vertical side and the horizontal side of the pixel, which is formed by the metal electrode, which is on the better side in the uniaxial orientation processing direction, is defined as the uniaxial orientation. A manufacturing method of a liquid crystal element, characterized in that a smaller one of angles formed with the processing direction is set to be an angle equal to or smaller than a predetermined angle, and an abnormal inversion phenomenon occurring on each side during driving is suppressed. Law. 8. At least one of two sides on the upper side with respect to the uniaxial orientation processing direction has a sawtooth shape, and the angle of the sawtooth is smaller than the angle formed by the sawtooth side and the axis orientation processing direction. 8. The method for manufacturing a liquid crystal element according to claim 7, wherein the angle is less than or equal to a predetermined angle. 9. The method of manufacturing a liquid crystal device according to claim 7, wherein the predetermined angle is 30 °. 10. The method for manufacturing a liquid crystal element according to claim 7, wherein the liquid crystal is a chiral smectic liquid crystal exhibiting at least two optically stable states. 11. The liquid crystal device according to claim 7, wherein a matrix electrode is formed by arranging the pair of substrates so as to face each other in a direction in which the transparent electrodes are orthogonal to each other, thereby enabling multiplexing driving. Production method.