JPH0792504A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display device which is wide in visual field angle, high in response speed and free from coloration. CONSTITUTION:This direct viewing type or projection type liquid crystal display device has a pair of substrates 11, at least two display electrodes 13 insulated from each other and formed on one substrate of a pair of these substrates 11 and a liquid crystal material sandwiched between a pair of the substrates 11 in the state of disposing a pair of the substrates 11 opposite to each other and makes display by providing the display electrodes 13 with a potential difference therebetween, thereby changing the arranging states of the liquid crystal molecules 12 in the liquid crystal material and controlling optical rotatory polarization. The liquid crystal material includes the liquid crystal molecules 12 having a twist direction in a direction reverse to the twist direction of the liquid crystal molecules 12 when the display electrodes 13 are provided with the potential difference therebetween.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art Liquid crystal display devices are thin and can be driven at a low voltage, and are therefore widely used as display devices for wrist watches, calculators and the like. In particular, a TN type liquid crystal display device incorporating an active switch element such as a TFT (thin film transistor) exhibits a display characteristic comparable to that of a CRT, and therefore has been used for a display of a word processor, a personal computer, a television, or the like. .

However, in the TN type liquid crystal display device, the viewing angle is narrow in the halftone display, and there is a large difference in color or contrast between the peripheral portion and the central portion of the display screen. This phenomenon is a display method in which the TN liquid crystal display method controls the optical rotatory power by applying an electric field to a nematic p-type liquid crystal material to erect liquid crystal molecules along the direction of the electric field, and the rising direction of the liquid crystal molecules is determined. It happens because you are Therefore, in the TN type liquid crystal display device,
The problem of viewing angle cannot be solved fundamentally.

In order to solve this problem, an electric field is applied in the lateral direction, that is, in the direction parallel to the substrate in a state where liquid crystal molecules are aligned as in the TN type liquid crystal display system, thereby controlling the optical rotation and displaying. The method of doing is proposed. However, in this method, it is known that the response speed, particularly the response speed of the trailing edge of the liquid crystal molecule is slow, and there are many problems in the display characteristics.

Further, a method of forming a comb-shaped electrode on a substrate for in-plane switching and controlling the optical rotatory power by applying it in a direction parallel to the substrate is not affected by rising of liquid crystal molecules. (RASoref, J.Appl.Phys. 45 , 5466 (1974). However, this method has a drawback that the response speed in the halftone display is slow and further coloring occurs.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display device having a wide viewing angle, a high response speed, and no coloring.

[0007]

The first and second aspects of the present invention
In the invention of 1, the reaction force of the liquid crystal molecules is generated when a potential difference is provided between the display electrodes by applying a load in the opposite direction to the twist direction of the liquid crystal molecules when the potential difference is provided between the display electrodes to the liquid crystal molecules in advance. This is done by paying attention to the fact that the size of the liquid crystal molecules increases and the speed at which the liquid crystal molecules change the alignment state increases.

According to a third aspect of the present invention, by providing a plurality of regions having different electric field strengths within the same pixel, the properties of the regions are mixed and the response speed is increased. Moreover, it was made paying attention to the fact that coloring can be prevented.

That is, according to the first aspect of the present invention, a pair of substrates, at least two display electrodes formed on one of the pair of substrates so as to be insulated from each other, and the display electrodes are inside. And a liquid crystal material sandwiched between the pair of substrates in a state where the pair of substrates face each other,
In a direct-view type or projection type liquid crystal display device that controls the optical rotation by changing the arrangement state of liquid crystal molecules in the liquid crystal material by providing a potential difference between the display electrodes, and the liquid crystal material is between the display electrodes. There is provided a liquid crystal display device including liquid crystal molecules having a twisting direction opposite to the twisting direction of the liquid crystal molecules when a potential difference is applied to the liquid crystal display device.

In a second aspect of the present invention, a pair of substrates, at least two display electrodes formed on one of the pair of substrates so as to be insulated from each other, and the display electrodes are inside. A liquid crystal material sandwiched between the pair of substrates in a state where the pair of substrates face each other, and a potential difference is provided between the display electrodes to change the alignment state of liquid crystal molecules in the liquid crystal material. In a direct-viewing type or projection type liquid crystal display device which controls optical rotation by means of the above, a pretilt angle θ of the liquid crystal molecules is 3 to 25 °.

A third aspect of the present invention is to provide a pair of substrates, a display electrode formed on the pair of substrates and applying an electric field in a direction parallel to the substrates, and the display electrode being inside. In a liquid crystal display device comprising a liquid crystal material sandwiched between the pair of substrates with the pair of substrates facing each other so that a plurality of display electrodes in the same pixel have different electric field strengths from each other. Provided is a liquid crystal display device, which is formed to have a region.

Here, in the present invention, a nematic liquid crystal material can be used as the liquid crystal material. In particular,
It is preferable to use LIXON 5034 (trade name, manufactured by Chisso Corporation) or the like, which has a high elastic constant for twisting. As the type of liquid crystal material, either a nematic p-type liquid crystal material or an n-type liquid crystal material can be used. However, in order to take advantage of the features of the liquid crystal display device of the present invention, nematic p-type liquid crystal material can be used.
It is preferable to use a type liquid crystal material.

As the substrate material, glass, quartz, silicon or the like can be used. Further, as the material of the display electrode, Al, Cr, Ti, Cu, Mo, Ta, In, I
A conductive metal such as TO, a metal oxide, a conductive polymer, or the like can be used.

In the first and second inventions, in order to provide all the matrix driving wirings on one of the pair of substrates, it is necessary to insulate the wirings from each other. Therefore, as a method of providing at least two display electrodes in an insulated manner, there is a method of providing an insulating layer made of an inorganic material such as SiOx or SiNx or a polymer material on a substrate, and providing the display electrodes on or on the side surface thereof. Can be mentioned. In this case, the thickness of the insulating layer is 3 in order to effectively use the electric field.
It is preferably 000 Å or more. Further, as the pattern of the display electrode, a structure in which two different display electrodes are alternately provided can be considered. In this case, it is preferable that the display electrode has a large thickness in view of display characteristics.
It is preferably 0 angstrom or more.

Further, when all electrodes are provided on one substrate of the pair of substrates as described above, it is possible to drive efficiently by setting all the one electrodes of each pixel to the same potential. In addition, by providing all the electrodes on one of the substrates, the electrodes can be used as spacers for keeping the distance between the substrates constant.

In the first and second inventions, the alignment direction of the liquid crystal molecules in the liquid crystal material does not have a viewing angle or a viewing angle direction as in the TN type liquid crystal display system. Can also be set. In this case, in order to prevent disclination, it is necessary to add a chiral agent to the liquid crystal material in advance and set the twist direction of the liquid crystal molecules in the opposite direction. However, the alignment direction of the liquid crystal molecules on the substrate provided with the electrodes is preferably set substantially perpendicular to the applied electric field, and particularly preferably 80 ° ≦ the alignment angle with respect to the electric field <90 °. This enables display with high contrast.

In the first aspect of the invention, as means for causing the liquid crystal molecules to have a twisting direction opposite to the twisting direction when a potential difference is provided between the display electrodes, twisting when a potential difference is provided between the display electrodes is provided. For example, a chiral agent that twists liquid crystal molecules in a direction opposite to the direction may be added to the liquid crystal material. Specifically, when the liquid crystal molecules are aligned by rotating to the right when an electric field is applied, a chiral agent whose twist direction is rotating to the left is added to the liquid crystal material. On the other hand, when the liquid crystal molecules are arranged to rotate counterclockwise when an electric field is applied, a chiral agent whose twist direction is clockwise is added to the liquid crystal material.

In this case, if the chiral pitch p in the state where the liquid crystal molecules in the liquid crystal material to which the chiral agent is added is naturally twisted is too long, the effect of the present invention becomes small, and if it is too short, the initial alignment is parallel alignment. Therefore, if the substrate spacing is d, p / 16 ≦ d <p
It is preferable to set so as to satisfy / 3. By setting the chiral pitch in this way, the alignment of the liquid crystal molecules becomes good, and a display with a high response speed can be performed. Therefore, the chiral agent needs to be added to the liquid crystal material in an amount that satisfies the above formula. As a chiral agent,
CM (manufactured by Chisso, trade name), C15 (manufactured by BDH, trade name), cholesterol nonanate and the like can be used.

In the second invention, the pretilt angle θ of the liquid crystal molecules in the liquid crystal material is set to 3 to 25 °. this is,
This is because if the pretilt angle θ is less than 3 °, the effect of the present invention is not sufficiently exhibited, and if it exceeds 25 °, the contrast decreases. When setting the pretilt angle θ of the liquid crystal molecules within the above range, SE3140 (Nissan Chemical Co., Ltd., trade name), A
A method of applying a rubbing treatment to an alignment film made of a material having a side chain alkyl group in the molecular structure or a material having an alkyl group in the molecular skeleton such as L3046 (manufactured by Japan Synthetic Rubber Co., Ltd.) Alternatively, a method of forming an alignment film by an oblique vapor deposition method can be adopted.

In the third invention, the plurality of regions having different electric field intensities in the display electrodes in the same pixel are, for example, a plurality of regions having different distances between electrode patterns, and electric elements such as resistors or capacitors connected in series. By connecting, it means a plurality of regions having mutually different electric field strengths.

In the first to third inventions, in order to prevent coloration, it is preferable that the alignment of liquid crystal molecules is parallel alignment and normally black in the absence of an electric field as an optimum condition for display.

In the first to third inventions, a clearer display can be realized by adopting an active matrix drive system in which an active switch element such as a TFT is provided for each pixel.

[0023]

The liquid crystal display device of the first invention of the present invention has at least two display electrodes formed on one of a pair of substrates so as to be insulated from each other, and a liquid crystal is provided by providing a potential difference between the display electrodes. In a direct-view type or projection type liquid crystal display device in which the optical rotatory power is controlled by changing the alignment state of liquid crystal molecules in the material to display, a twisting direction of the liquid crystal molecules when the liquid crystal material provides a potential difference between the display electrodes, It is characterized by including liquid crystal molecules having opposite twist directions.

As shown in FIG. 1 (A), the above display method,
That is, in the system in which an electric field is applied in parallel (transverse direction) to the surface of the substrate 11, the nematic p-type liquid crystal molecules 12 that are aligned in parallel are aligned in the electric field direction as shown in FIG. Try to change the orientation. this is,
The tendency becomes stronger as it is closer to the electrode 13 provided on one of the substrates 11. As a result, the optical rotatory power due to the initial twist orientation disappears, and the linearly polarized light incident on the liquid crystal cell through the polarizing plate exits from the liquid crystal cell without changing its polarization plane.

In this display method, when the alignment direction is changed to the direction of the electric field only by the horizontal electric field, as shown in FIG. 2, the larger the strain applied to the liquid crystal alignment in the initial alignment state, the more the electric field is removed. It was found that the liquid crystal molecule has a high deflection speed, that is, a response speed when returning to the initial alignment state. It is considered that this is because when the electric field is applied due to the strain applied to the liquid crystal alignment, the torque becomes larger than usual and the force for returning the orientation of the liquid crystal molecules becomes larger.

Based on this fact, the direction in which the liquid crystal molecules rotate when the liquid crystal molecules are aligned by applying an electric field,
The torque applied to the liquid crystal material is increased by preliminarily imparting to the liquid crystal material a distortion in the natural twist direction (clockwise in the figure), which is the twist direction opposite to the electric field induced twist direction (counterclockwise in the figure), and Orient quickly. As a result, the response speed becomes faster.

A liquid crystal display device according to a second aspect of the present invention has at least two display electrodes formed on one of a pair of substrates so as to be insulated from each other, and a liquid crystal is provided by providing a potential difference between the display electrodes. In a direct-view type or projection type liquid crystal display device that controls the optical rotatory power by changing the alignment state of liquid crystal molecules in a material for display, the pretilt angle θ of the liquid crystal molecules is 3 to
It is characterized in that it is 25 °.

As shown in FIG. 3, when the pretilt angle θ of the liquid crystal molecules is set to 3 to 25 °, distortion is added to the liquid crystal alignment of the liquid crystal material. In this case, when an electric field is applied, the liquid crystal molecules quickly turn due to the action of spray and vent. Therefore, the response speed becomes faster. Furthermore, this pretilt angle θ is
Considering the wavelength dependence, 2 μm ≦ with the substrate distance d
It is preferable that d · cos θ ≦ 7 μm. This improves the display quality.

A liquid crystal display device according to a third aspect of the present invention is formed between a pair of substrates and a display electrode for applying an electric field in a direction parallel to the substrates and a pair of the substrates facing each other between the substrates. In a liquid crystal display device including a sandwiched liquid crystal material, display electrodes in the same pixel are formed to have a plurality of regions having different electric field strengths.

In the above display method, coloring occurs in the halftone state, as shown in FIG. Also, regarding the response speed, satisfactory results are obtained in the case of binary display, but extremely slow in the case of halftone display. Therefore, by setting a region having a plurality of electric field intensities in each pixel, it is possible to improve response speed and prevent coloring by using a mixture of the properties of each region as the entire property. For example, the response speed in the halftone display can be expressed as a mixture of three regions of an ON part, an OFF part, and an intermediate part in the comb electrode as shown in FIG. 5, and by limiting the region of the intermediate part, The response speed can be improved.

As shown in FIG. 6, when a plurality of regions having different electric field intensities are set in each pixel by changing the inter-electrode distance, the electric field intensity becomes strong in a place where the inter-electrode distance is short, The electric field strength becomes weak in a place where the distance between the electrodes is long. Further, as shown in FIG. 7, it may be formed in a plurality of regions in which the distance between the electrodes is gradually changed.
In this case, the relationship between the applied voltage in each region and the light transmittance (in the case of normally black) is as shown in FIG. At this time, even in the halftone region, the respective 1/3 regions are completely ON and OFF. Then, the middle portion becomes 1/3, and the response speed can be increased and the coloring can be eliminated.

In the above display method, since two electrodes are provided on one substrate, the distance between the electrodes can be set accurately and freely only by patterning the electrodes.
In this way, it is possible to obtain gradation in a single pixel when matrix driving is performed.

[0033]

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

Example A1 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 500 Å, and a line width of 5 μm and a line spacing of 10 μm were used for each pixel by using a positive type photosensitive resist. Two
Two electrodes were formed. Then, after forming an alignment film on the electrode, the film is rotated clockwise (clockwise) with respect to the longitudinal direction of the electrode.
The alignment film was subjected to rubbing alignment treatment while being shifted. Furthermore, after forming an alignment film on another glass substrate and performing alignment treatment, the two substrates are opposed to each other so that the alignment directions are parallel alignment, and a glass fiber having an outer diameter of 5 μm is sandwiched as a spacer to form a liquid crystal cell Was produced.

Then, a left-handed chiral pitch 20 is prepared by adding 0.5% by weight of CM to the LIXON 5034.
A nematic p-type liquid crystal material with μm and Δn = 0.10 was injected into the liquid crystal cell. The direction of the polarizing plate was normally black. Thus, the liquid crystal display device of the first invention was obtained.

The difference between the adjacent electrodes of this liquid crystal display device is ± 10.
When a voltage of V is applied, the fall response speed is 100
Good display was obtained with a contrast ratio of 50: 1 for nsec.

Example A2 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 5000 Å, and a line width of 5 μm and a line interval of 5 μm were formed using a positive photosensitive resist for each pixel. Two electrodes were formed. Then, after forming an alignment film on the electrode, the alignment film was subjected to a rubbing alignment treatment by being shifted clockwise (clockwise) by 1 ° with respect to the longitudinal direction of the electrode. Furthermore, after forming an alignment film on another glass substrate and performing alignment treatment, the two substrates are opposed to each other so that the alignment directions are parallel alignment, and a glass fiber having an outer diameter of 5 μm is sandwiched as a spacer to form a liquid crystal cell Was produced.

Next, a nematic p-type liquid crystal material having a left-handed chiral pitch of 50 μm and Δn = 0.10 prepared by adding 0.4% by weight of cholesterol nonanate as a chiral agent to LIXON 5034 was injected into a liquid crystal cell. The direction of the polarizing plate was normally black. Thus, the liquid crystal display device of the first invention was obtained.

The difference between the adjacent electrodes of this liquid crystal display device is ± 10.
When a voltage of V is applied, the fall response speed is 100
Good display with msec and a contrast ratio of 100: 1 was obtained.

Example A3 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 500 Å, and a line width of 3 μm and a line spacing of 6 μm were used for each pixel by using a positive type photosensitive resist. The electrode was formed. Next, aluminum is vapor-deposited on the electrodes to form an aluminum film having a thickness of 5000 Å, and aluminum selective etching is performed using a positive photosensitive resist to leave the aluminum film on only one electrode. One electrode was formed by etching an aluminum film so that only the ITO film remained on the surface.
At this time, the line width of the ITO electrode is 3 μm, the space between the lines is 1.5 μm,
The line width of the aluminum electrode was 3 μm, and the distance between the lines was 1.5 μm. In this way, two kinds of electrodes were alternately formed. At this time, by sufficiently lengthening the patterning time of the aluminum film, the vicinity of the interface with the glass substrate is over-etched and the bonding surface of the glass substrate has a line width of 2 μm.
It became an inverted trapezoid of m.

Next, after forming an alignment film on the electrode, the alignment film was subjected to rubbing alignment treatment by shifting it by 1 ° in the clockwise direction (right rotation) with respect to the longitudinal direction of the electrode. Furthermore, another 1
After forming the alignment film on the glass substrate and performing the alignment treatment,
Two substrates were opposed to each other so that the alignment direction was twisted clockwise by 90 °, and a glass fiber having an outer diameter of 6 μm was sandwiched as a spacer to prepare a liquid crystal cell.

Next, a counterclockwise chiral pitch 10 formed by adding 0.1% by weight of a chiral agent C15 to LIXON 5034.
A nematic p-type liquid crystal material of 0 μm and Δn = 0.10 was injected into the liquid crystal cell. The direction of the polarizing plate was normally black. Thus, the liquid crystal display device of the first invention was obtained.

± 6 V is applied between adjacent electrodes of this liquid crystal display device.
When the voltage is applied, the fall response speed is 100 ms
A good display with ec and a contrast ratio of 100: 1 was obtained.

Example A4 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 1000 Å. On top of that, using a negative photosensitive polyimide, the line width is 3 μm, the line spacing is 5 μm,
An insulating layer having a height of 2 μm was formed. Then IT on this
Two electrodes were formed through an insulating layer by vapor-depositing O to form an ITO film having a thickness of 100 Å.

Then, after forming an alignment film on the electrode, the alignment film was subjected to rubbing alignment treatment by shifting it by 0.5 ° in the clockwise direction (clockwise rotation) with respect to the longitudinal direction of the electrode. Furthermore, after forming an alignment film on another glass substrate and performing alignment treatment, the two substrates are made to face each other so that the alignment directions are parallel alignment, and a glass fiber having an outer diameter of 5 μm is sandwiched as a spacer to form a liquid crystal cell. Was produced.

Next, a nematic p-type liquid crystal material having a left-handed chiral pitch of 50 μm and Δn = 0.10, which was prepared by adding 0.4% by weight of cholesterol nonanate as a chiral agent to LIXON 5032, was injected into the liquid crystal cell. The direction of the polarizing plate was normally black. Thus, the liquid crystal display device of the first invention was obtained.

± 8 V is applied between adjacent electrodes of this liquid crystal display device.
When the voltage of is applied, the fall response speed is 50 mse
c, a good display with a contrast ratio of 100: 1 was obtained.

Comparative Example A1 A liquid crystal display cell was prepared in the same manner as in Example A1. Then, a nematic p-type liquid crystal material having a right-handed chiral pitch of 50 μm and Δn = 0.10, which was prepared by adding 0.4% by weight of cholesterol chloride as a chiral agent to LIXON 5032, was injected into the liquid crystal cell. The direction of the polarizing plate was normally black. Thus, a liquid crystal display device was obtained.

The difference between the adjacent electrodes of this liquid crystal display device is ± 10.
When a voltage of V is applied, the falling response speed is 500
It was slow as msec, and good display could not be obtained.

Comparative Example A2 A liquid crystal display cell was prepared in the same manner as in Example A1. Next, a nematic p-type liquid crystal material having a counterclockwise rotation chiral pitch of 10 μm and Δn = 0.10, which was obtained by adding 1% by weight of a chiral agent CM to LIXON 5048, was injected into a liquid crystal cell. In addition,
The polarizing plate direction was normally black. Thus, a liquid crystal display device was obtained. In this case, the initial orientation was twisted by 180 ° because the chiral pitch was too short.

± 10 is provided between the adjacent electrodes of this liquid crystal display device.
When a voltage of V is applied, the fall response speed is 300
It was slow as msec, and good display could not be obtained.

Example B1 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 500 Å, and a line width of 5 μm and a line spacing of 10 μm were used for each pixel using a positive type photosensitive resist. Two electrodes were formed. Then, after forming an alignment film on the electrode, the alignment film was subjected to rubbing alignment treatment. further,
After forming an alignment film on another glass substrate and performing alignment treatment, the two substrates are made to face each other so that the alignment directions are parallel alignment, and a glass fiber with an outer diameter of 5 μm is sandwiched as a spacer to produce a liquid crystal cell. did.

Then, a chiral pitch of 20 μm and Δ formed by adding 0.5% by weight of a chiral agent C15 to LIXON 5034
A nematic p-type liquid crystal material with n = 0.10 was injected into the liquid crystal cell. At this time, the pretilt angle θ was 3 °. The direction of the polarizing plate was normally black. Thus, the liquid crystal display device of the second invention was obtained.

± 10 between adjacent electrodes of this liquid crystal display device
When a voltage of V is applied, the fall response speed is 100
Good display was obtained with a contrast ratio of 50: 1 for nsec.

Example B2 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 5000 Å, and a line width of 5 μm and a line spacing of 5 μm were formed using a positive photosensitive resist for each pixel. Two electrodes were formed. Then, after forming an alignment film on the electrode, the alignment film was subjected to a rubbing alignment treatment while being shifted by 1 ° with respect to the longitudinal direction of the electrode. Furthermore, after forming an alignment film on another glass substrate and performing alignment treatment, the two substrates are made to face each other so that the alignment directions are parallel alignment, and a glass fiber having an outer diameter of 5 μm is sandwiched as a spacer to form a liquid crystal cell. Was produced.

Next, 0.4 wt% of cholesterol nonanate as a chiral agent was added to LIXON 5034 to obtain a nematic p having a chiral pitch of 50 μm and Δn = 0.10.
A mold liquid crystal material was injected into the liquid crystal cell. At this time, the pretilt angle θ was 5 °. The direction of the polarizing plate was normally black. Thus, the liquid crystal display device of the second invention was obtained.

± 10 between adjacent electrodes of this liquid crystal display device
When a voltage of V is applied, the fall response speed is 100
Good display was obtained with a contrast ratio of 50: 1 for nsec.

Example B3 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 500 Å, and a line width of 3 μm and a line spacing of 6 μm were used for each pixel using a positive type photosensitive resist. The electrode was formed. Next, aluminum is vapor-deposited on the electrodes to form an aluminum film having a thickness of 5000 Å, and aluminum selective etching is performed using a positive photosensitive resist to leave the aluminum film on only one electrode. One electrode was formed by etching an aluminum film so that only the ITO film remained on the surface.
At this time, the line width of the ITO electrode is 3 μm, the space between the lines is 1.5 μm,
The line width of the aluminum electrode was 3 μm, and the distance between the lines was 1.5 μm. In this way, two kinds of electrodes were alternately formed. At this time, by sufficiently lengthening the patterning time of the aluminum film, the vicinity of the interface with the glass substrate is over-etched and the bonding surface of the glass substrate has a line width of 2 μm.
It became an inverted trapezoid of m.

Then, after forming an alignment film on the electrode, the alignment film was subjected to rubbing alignment treatment by shifting it by 1 ° in the clockwise direction (right rotation) with respect to the longitudinal direction of the electrode. Furthermore, another 1
After forming the alignment film on the glass substrate and performing the alignment treatment,
Two substrates were opposed to each other so that the alignment direction was twisted clockwise by 90 °, and a glass fiber having an outer diameter of 6 μm was sandwiched as a spacer to prepare a liquid crystal cell.

Next, a counterclockwise chiral pitch 10 formed by adding 0.1% by weight of CM to the LIXON 5032
A nematic p-type liquid crystal material of 0 μm and Δn = 0.10 was injected into the liquid crystal cell. At this time, the pretilt angle θ was 8 °. The direction of the polarizing plate was normally black. Thus, the liquid crystal display devices of the first and second inventions were obtained.

± 6 V is applied between adjacent electrodes of this liquid crystal display device.
When the voltage of is applied, the fall response speed is 60 mse
A good display with a contrast ratio of 90: 1 was obtained.

Example B4 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 1000 Å. On top of that, using a negative photosensitive polyimide, the line width is 3 μm, the line spacing is 5 μm,
An insulating layer having a height of 2 μm was formed. Then IT on this
Two electrodes were formed through an insulating layer by vapor-depositing O to form an ITO film having a thickness of 100 Å.

Next, after forming an alignment film on the electrodes, oblique vapor deposition of SiO was performed at a vapor deposition angle of 90 ° with a shift of 0.5 ° clockwise (right rotation) with respect to the longitudinal direction of the electrodes. Furthermore, after forming an alignment film on another glass substrate and performing alignment treatment, the two substrates are made to face each other so that the alignment directions are parallel alignment, and a glass fiber having an outer diameter of 5 μm is sandwiched as a spacer to form a liquid crystal cell. Was produced.

Next, a nematic p-type liquid crystal material having a left-handed chiral pitch of 100 μm and Δn = 0.10, which was prepared by adding 0.4% by weight of cholestrol nonanate as a chiral agent to LIXON 5032, was injected into the liquid crystal cell. At this time, the pretilt angle θ was 25 °. The direction of the polarizing plate was normally black. Thus, the liquid crystal display device of the first invention was obtained.

± 8 V is applied between adjacent electrodes of this liquid crystal display device.
When the voltage of is applied, the fall response speed is 50 mse
c, a good display with a contrast ratio of 100: 1 was obtained.

Comparative Example B1 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 500 Å, and a line width of 5 μm and a line spacing of 10 μm were used for each pixel using a positive type photosensitive resist. Two electrodes were formed. Then, after forming an alignment film on the electrodes, oblique alignment of SiO was performed at a deposition angle of 85 ° while shifting the alignment film by 2 ° with respect to the longitudinal direction of the electrodes. further,
After forming an alignment film on another glass substrate and performing alignment treatment, the two substrates are made to face each other so that the alignment directions are parallel alignment, and a glass fiber with an outer diameter of 2 μm is sandwiched as a spacer to produce a liquid crystal cell. did.

Then, a nematic p having a chiral pitch of 50 μm and Δn = 0.10, which is prepared by adding 0.4% by weight of cholesteryl nonanate as a chiral agent to LIXON 5032.
A mold liquid crystal material was injected into the liquid crystal cell. At this time, the pretilt angle θ was 30 °. The direction of the polarizing plate was normally black. Thus, a liquid crystal display device was obtained.

± 10 is provided between the adjacent electrodes of this liquid crystal display device.
When a voltage of V was applied, the contrast was 5: 1, and good display was not obtained.

Comparative Example B2 ITO was vapor-deposited on one glass substrate to form an ITO film having a thickness of 500 Å, and a line width of 5 μm and a line spacing of 10 μm were used for each pixel using a positive type photosensitive resist. Two electrodes were formed. Then, after forming an alignment film on the electrode, the alignment film is formed by rotating the alignment film in a clockwise direction with respect to the longitudinal direction of the electrode.
Rubbing alignment treatment was performed by shifting the angle. Furthermore, another 1
After forming the alignment film on the glass substrate and performing the alignment treatment,
Two substrates were opposed to each other so that the alignment directions were parallel alignment, and a glass fiber having an outer diameter of 8 μm was sandwiched as a spacer to prepare a liquid crystal cell.

Next, a chiral pitch of 100 μm prepared by adding 0.1% by weight of a chiral agent C15 to LIXON 5048,
A nematic p-type liquid crystal material with Δn = 0.10 was injected into the liquid crystal cell. At this time, the pretilt angle θ became 1 °.
The direction of the polarizing plate was normally black. Thus, a liquid crystal display device was obtained.

The difference between the adjacent electrodes of this liquid crystal display device is ± 10.
When a voltage of V is applied, the fall response speed is 30
It was as slow as 0 msec and the contrast was 50: 1, and good display could not be obtained.

Example C1 TFT switch elements were provided on one glass substrate, and further, as shown in FIG. 6, ITO electrodes having a pattern in which two comb shapes were intermeshed were formed in a matrix with respect to the wiring. At this time, the distance between the electrodes is 10 at the widest point.
μm, and 1 μm at the narrowest point. In this way, a plurality of regions having different electric field strengths were provided. The other substrate was provided with a black matrix corresponding to the wiring.

Solvent-soluble ring-closure type polyimide was applied onto two substrates and dried to form an alignment film, and the alignment film was subjected to a rubbing treatment with a shift of 1 ° with respect to the longitudinal direction of the electrode. A liquid crystal cell was prepared by facing the two substrates so as to be parallel to each other at 90 ° and sandwiching micropearls (product name: Sekisui Fine Chemical Co., Ltd.) having an outer diameter of 6 μm as spacers.

Next, a nematic p-type liquid crystal material was injected into this liquid crystal cell to manufacture a liquid crystal display device of the third invention.

This liquid crystal display device had a wide viewing angle and a contrast of 10: 1 and 60 °. In addition, the response speed was high even in the halftone state, and there was no coloring.

Example C2 A TFT switch element was provided on one glass substrate, and further, ITO electrodes having a pattern in which two combs were engaged with each other were formed in a matrix with respect to the wiring as shown in FIG. At this time, the distance between the electrodes is 10 at the widest point.
μm, and 1 μm at the narrowest point. In this way, a plurality of regions having different electric field strengths were provided. The other substrate was provided with a black matrix corresponding to the wiring.

Solvent-soluble closed-ring type polyimide was applied onto two substrates and dried to form an alignment film, and the alignment film was subjected to a rubbing treatment with a shift of 1 ° with respect to the longitudinal direction of the electrode. A liquid crystal cell was produced by facing the two substrates so as to be parallel to each other at 90 ° and sandwiching micropearls having an outer diameter of 6 μm as spacers.

Next, a nematic p-type liquid crystal material was injected into this liquid crystal cell to manufacture the liquid crystal display device of the third invention.

This liquid crystal display device had a wide viewing angle and a contrast of 10: 1 and 60 °. In addition, the response speed was high even in the halftone state, and there was no coloring.

Example C3 TFT switch elements were provided on one glass substrate, and further, ITO electrodes having a pattern in which two combs were meshed with each other were formed in a matrix with respect to the wiring as shown in FIG. At this time, the distance between the electrodes is 10 at the widest point.
μm, and 1 μm at the narrowest point. The other substrate was provided with a black matrix corresponding to the wiring.

Solvent-soluble ring-closure type polyimide was applied onto two substrates and dried to form an alignment film, and the alignment film was subjected to a rubbing treatment with a shift of 1 ° with respect to the longitudinal direction of the electrode. A liquid crystal cell was produced by making the two substrates face each other so as to have a 90 ° TN orientation, and sandwiching micropearls having an outer diameter of 6 μm as spacers.

Next, a nematic p-type liquid crystal material was injected into this liquid crystal cell to manufacture the liquid crystal display device of the third invention.

This liquid crystal display device had a wide viewing angle and a contrast of 10: 1 and 60 °. In addition, the response speed was high even in the halftone state, and there was no coloring.

Comparative Example C1 A TFT switch element was provided on one glass substrate, and further, as shown in FIG. 9, ITO electrodes having a pattern in which two comb shapes were intermeshed were formed in a matrix with respect to the wiring. At this time, the distances between the electrodes were all 10 μm. The other substrate was provided with a black matrix corresponding to the wiring.

Solvent-soluble ring-closure type polyimide was applied onto two substrates and dried to form an alignment film, and the alignment film was subjected to a rubbing treatment with a shift of 1 ° with respect to the longitudinal direction of the electrode. A liquid crystal cell was produced by facing the two substrates so as to be parallel to each other at 90 ° and sandwiching micropearls having an outer diameter of 6 μm as spacers.

Next, a nematic p-type liquid crystal material was injected into this liquid crystal cell to manufacture a liquid crystal display device.

The liquid crystal display device had a wide viewing angle and a contrast of 10: 1 and 60 °. However, in the halftone state, the response speed was slow and coloring occurred.

Comparative Example C2 A TFT switch element was provided on one glass substrate, and further, as shown in FIG. 9, ITO electrodes having a pattern in which two combs were intermeshed were formed in a matrix with respect to the wiring. At this time, the distances between the electrodes were all 10 μm. ITO electrodes are formed on the entire surface of the other substrate,
A black matrix corresponding to the wiring was provided.

Solvent-soluble ring-closing polyimide was applied onto two substrates and dried to form an alignment film, and the alignment film was subjected to a rubbing treatment while being shifted by 1 ° with respect to the longitudinal direction of the electrode. A liquid crystal cell was produced by making the two substrates face each other so as to have a 90 ° TN orientation, and sandwiching micropearls having an outer diameter of 6 μm as spacers.

Then, a nematic p-type liquid crystal material was injected into this liquid crystal cell to manufacture a liquid crystal display device.

This liquid crystal display device has a narrow viewing angle, and color inversion occurs depending on the viewing direction.

[0092]

As described above, the liquid crystal display device of the present invention has at least two display electrodes formed on one of a pair of substrates and insulated from each other, and a potential difference is provided between the display electrodes. In a direct-view type or projection type liquid crystal display device that controls the optical rotation by changing the arrangement state of liquid crystal molecules in the liquid crystal material to display, the twist direction of the liquid crystal molecules when the liquid crystal material provides a potential difference between the display electrodes. And a pretilt angle θ of the liquid crystal molecules is 3 to 25 °.

Further, the liquid crystal display device of the present invention is sandwiched between the pair of substrates, with the pair of substrates facing each other and the display electrodes for applying an electric field in the direction parallel to the substrates. In a liquid crystal display device including a liquid crystal material, display electrodes in the same pixel are formed to have a plurality of regions having different electric field strengths.

As a result, good display with a wide viewing angle, a high response speed, and a low threshold voltage can be performed.

[Brief description of drawings]

FIG. 1A is a schematic view showing a state in which no electric field is applied in the liquid crystal display device of the first invention of the present invention. FIG. 3B is a schematic diagram showing an electric field applied state in the liquid crystal display device of the first invention of the present invention.

FIG. 2 is an explanatory view showing the movement of liquid crystal molecules in the liquid crystal display device of the first invention of the present invention.

FIG. 3 is a schematic view showing a liquid crystal display device of a second invention of the present invention.

FIG. 4 is a graph showing changes in chromaticity in a display system in which a horizontal electric field is applied.

FIG. 5 is a graph showing the relationship between applied voltage and response speed in a liquid crystal display device.

FIG. 6 is a schematic view showing an example of display electrodes of a liquid crystal display device according to a third invention of the present invention.

FIG. 7 is a schematic view showing another example of the display electrode of the liquid crystal display device of the third invention of the present invention.

8 is a graph showing the relationship between applied voltage and light transmittance in the liquid crystal display device having the display electrode shown in FIG.

FIG. 9 is a schematic view showing a conventional comb-shaped electrode in a liquid crystal display device.

[Explanation of Codes] 11 ... Substrate, 12 ... Liquid crystal molecule, 13 ... Electrode.

Claims (3)

[Claims] 1. A pair of substrates, at least two display electrodes formed on one of the pair of substrates so as to be insulated from each other, and the pair of substrates facing each other so that the display electrodes are inside. And a liquid crystal material sandwiched between the pair of substrates in this state, a potential difference is provided between the display electrodes to change the alignment state of liquid crystal molecules in the liquid crystal material, thereby controlling the optical rotatory power to display an image. In the direct-view type or projection type liquid crystal display device, the liquid crystal material includes liquid crystal molecules having a twist direction opposite to a twist direction of the liquid crystal molecules when a potential difference is provided between the display electrodes. Display device. 2. A pair of substrates, at least two display electrodes formed on one of the pair of substrates so as to be insulated from each other, and the pair of substrates facing each other so that the display electrodes are inside. And a liquid crystal material sandwiched between the pair of substrates in this state, a potential difference is provided between the display electrodes to change the alignment state of liquid crystal molecules in the liquid crystal material, thereby controlling the optical rotatory power to display an image. In the direct-view type or projection type liquid crystal display device, the pretilt angle θ of the liquid crystal molecules is 3
A liquid crystal display device, wherein the liquid crystal display device has an angle of -25 °. 3. A pair of substrates, a display electrode that is formed on the pair of substrates and applies an electric field in a direction parallel to the substrates, and the pair of substrates such that the display electrodes are inside. In a liquid crystal display device including a liquid crystal material sandwiched between the pair of substrates in a state of facing each other, the display electrodes in the same pixel are formed to have a plurality of regions having different electric field strengths. A liquid crystal display device characterized by the above.