JPH0643467A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To prevent the electrification of spacers without reducing the specific resistance of a liq. crystal material and to enhance the qualilty of a picture displayed by a liq. crystal display device. CONSTITUTION:Upper and lower electrode substrates 11, 12 are superposed at a prescribed interval left by many spacers 1 interposed between the substrates 11, 12 so that faces of the substrates 11, 12 with formed transparent picture element electrodes confront each other, a liq. crystal 50 is sealed in the gap between the substrates 11, 12 to form a liq. crystal display cell and a liq. crystal display device with the cell is produced. At this time, the surfaces of the spacers 10 are coated with a nonionic surfactant or this surfactant is incorporated into the material of the spacers 1 by kneading.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple matrix type or active matrix type liquid crystal display device having a liquid crystal display element, and more particularly to a spacer for defining a distance between two transparent substrates constituting the liquid crystal display element. The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art A conventional twisted nematic type of liquid crystal display device has a 90 ° twisted helix structure made of nematic liquid crystal having a positive dielectric anisotropy between two electrode substrates, and A pair of polarizing plates is arranged outside the electrode substrate such that the polarization axis (or absorption axis) thereof is orthogonal or parallel to the axis of liquid crystal molecules adjacent to the electrode substrate (Japanese Patent Publication No. 13666
Issue).

In such a liquid crystal display device having a twist angle of 90 °, there are problems in the steepness γ of the change in the transmittance of the liquid crystal layer with respect to the voltage applied to the liquid crystal layer and in the viewing angle characteristics. The practical limit was 64 for the number of electrodes). However, in order to cope with recent demands for improving image quality and increasing the amount of display information for liquid crystal display elements, the twist angle α of liquid crystal molecules sandwiched between a pair of polarizing plates is set to be larger than 180 °, and the voltage applied to this liquid crystal layer is increased. Applying physics by TJ Scheffer and J. Nailing to improve the time-division drive characteristics and increase the number of time-divisions by adopting a configuration that detects changes in the birefringence effect of the liquid crystal layer due to
Letter 45, No. 10, 1021, 1984 "Ann Hailey
Multiplexer "(Applied Physics Letter, T.J.
Scheffer, J. Nehring: “A new, highly multiplexabl
e liquid crystal display ”), and a super twisted birefringence effect (SBE) liquid crystal display device has been proposed.

In the conventional liquid crystal display device, two transparent glass substrates are superposed at a predetermined interval so that the surfaces on which the transparent electrodes and the alignment film are laminated face each other, and the transparent glass substrates are arranged around the edge between the two substrates. A liquid crystal display element in which the two substrates are bonded to each other and a liquid crystal is sealed between the two substrates by a sealing material provided, and a backlight which supplies light to the liquid crystal display element disposed below the liquid crystal display element, A printed circuit board which is arranged on the outside of three sides of the liquid crystal display element or under the backlight and has a drive circuit for the liquid crystal display element, and a metal frame in which each of these members is housed and a liquid crystal display window is opened. It consists of

The two transparent glass substrates of the above liquid crystal display device are stacked with a predetermined gap (gap) therebetween. To define this gap, a large number of small spherical or columnar shapes are used. First, use an air blower or the like on the alignment film surface that has been subjected to the alignment treatment (treatment of providing a number of predetermined narrow grooves by rubbing to set the orientation of liquid crystal molecules) formed on one transparent glass substrate. To evenly disperse a large number of spacers. Alternatively, an alignment treatment is performed after depositing an alignment film material mixed with a large number of spacers to form an alignment film. Then, two transparent glass substrates are stacked so that their alignment films face each other, and a large number of spacers are interposed between the two substrates, so that the two substrates are separated by a predetermined distance. After that, liquid crystal is sealed between both substrates from a liquid crystal sealing port provided in a part of a sealing material provided around the edge of the substrate, and the liquid crystal is sealed by the sealing material to manufacture a liquid crystal display element.

[0006]

Conventionally, as a material for a spacer of a liquid crystal display device, for example, an inorganic material such as hard glass fiber, alumina particles, silica particles and divinylbenzene-based crosslinked polymer particles (polymer beads) are used. , Organic materials such as polystyrene are used. The spacers made of these materials all had high surface resistivity (electrical resistivity) of 10 ¹³ Ω · cm or more.

On the other hand, the specific resistance of the liquid crystal material in a state of being sealed between both substrates of the liquid crystal display element is usually 10 ⁹ Ω · cm.
As described above, when the specific resistance of the liquid crystal material is lowered, the driving characteristic of the liquid crystal by the low frequency voltage is lowered, and the display image quality is lowered. Therefore, in order to prevent a decrease in the specific resistance of the liquid crystal material, the specific resistance of the spacers present in the liquid crystal material needs to be about 10 ¹³ Ω · cm. A polyimide resin is generally used as a material for the alignment film that controls the alignment of the liquid crystal material, and the specific resistance of this film is as high as 10 ¹³ Ω · cm or more.

In a liquid crystal display element, when the spacers are charged with static electricity or the charged spacers are densely packed, the contrast is partially changed due to the fluctuation of the threshold value of the liquid crystal material existing around the spacers. However, there is a problem that the display quality is degraded. Therefore, in order to discharge this static electricity, the spacer must be left at a high temperature for a long time.

When manufacturing a liquid crystal display element, static electricity is generated in each process such as rubbing for alignment treatment, handling by an operator, encapsulation of a liquid crystal material, or attachment of a polarizing plate to the liquid crystal display element. However, the spacer is often charged. Of these, in particular, when the liquid crystal material is sealed in the liquid crystal display element, the spacer is charged by the flow charging. This flow charge amount is greatly affected by the potential difference between the liquid crystal material and the spacer, the potential difference between the liquid crystal material and the alignment film, and the dielectric constants of these materials. In particular, in order to prevent the spacers from being charged, it is necessary to reduce the potential difference between the spacers and the liquid crystal material. For that purpose, the specific resistance of the spacer (10 ¹³ Ω · cm or more) is set to the specific resistance of the liquid crystal material (10 ⁹ Ω · cm).
Ω · cm or more), that is, it is necessary to reduce the specific resistance of the spacer to about 10 ⁹ to 10 ¹² Ω · cm.

Conventionally, in order to reduce the specific resistance of the spacer, there has been proposed a method of applying a silane coupling agent to the surface of the spacer when the spacer is the above-mentioned inorganic material. However, with this method, it is difficult to control the specific resistance of the spacer in mass production. That is, it is difficult to reduce the specific resistance of a silane coupling agent having polarity such as aminosilane, and it is difficult to reduce the specific resistance of alkylsilane having no polarity.

An object of the present invention is to prevent a decrease in the specific resistance of a liquid crystal material, which causes deterioration of display image quality, by a spacer, and prevent the spacer from being charged.
An object of the present invention is to provide a liquid crystal display device having a spacer having a specific resistance of about 0 ⁹ to 10 ¹² Ω · cm.

[0012]

In order to solve the above problems, the present invention provides a large number of spacers between the two transparent substrates so that the surfaces of the two transparent substrates provided with the transparent pixel electrodes face each other. In a liquid crystal display device having a liquid crystal display element which is superposed with a predetermined space therebetween and which has a liquid crystal sealed between the both substrates, is a nonionic surfactant applied to the surface of the spacer? Or a liquid crystal display device in which a nonionic surfactant is kneaded into the material of the spacer.

Among the surfactants, in the case of a zwitterionic or ionic surfactant, the specific resistance is too low, and it is difficult to control the specific resistance of the spacer, as in the case of the polar silane. .

The specific resistance of the spacer is about 10 ⁹ to 10 ¹² Ω.
Examples of nonionic surfactants that can be controlled to about cm are alkyl ether type and alkyl allyl ether type such as polyoxyethylene adduct of nonylphenyl ether and polyoxyethylene adduct of octylphenyl ether. Alternatively, there are alkyl ester type such as polyoxyethylene adduct of alkylphenyl ester, sorbitan alkyl ester type, polyoxyethylene polyoxypropylene and the like.

In the case of a spacer made of an organic material, a nonionic surfactant is applied to the surface of the spacer,
In the case of a spacer made of an inorganic material, the surface of the spacer is coated with a nonionic surfactant or the spacer material is kneaded with a nonionic surfactant. A liquid crystal display device using such a spacer was produced, and an experiment was conducted as to whether or not a defect due to static electricity would occur. According to the experimental results, it is recognized that the effect is more effective when the spacer is made of the organic material than when the spacer is made of the inorganic material. It is thought to be an influence.

[0016]

In the liquid crystal display device of the present invention, a nonionic surfactant is applied to the surface of the spacer that defines the distance between the two transparent substrates that form the liquid crystal display element, or the spacer material is nonionic. By kneading the system surfactant, the specific resistance of the spacer can be mass-produced and controlled to about 10 ⁹ to 10 ¹² Ω · cm. Therefore, since the spacer has a specific resistance of about 10 ⁹ to 10 ¹² Ω · cm, it is possible to solve the problem that the display quality is deteriorated due to the decrease in the specific resistance of the liquid crystal material existing around the spacer.
Further, since the specific resistance of the spacer can be made close to the specific resistance of the liquid crystal material, it is possible to reduce the potential difference between the spacer and the liquid crystal material, and as a result, it is possible to reduce the flow charge amount when the liquid crystal material is sealed, It is possible to prevent the spacer from being charged. Furthermore, the charges charged on the spacers can be transferred into the liquid crystal material or the alignment film, and the charging can be prevented. Since the spacers can be prevented from being charged in this manner, the conventional problems that the electrical characteristics of the liquid crystal material become non-uniform, the optical characteristics of the liquid crystal display element change, and the display image quality deteriorates can be solved.

[0017]

1 (a) is a sectional view of a liquid crystal display element according to an embodiment of the present invention, and FIG. 1 (b) is a plan view of the liquid crystal display element shown in FIG. 1 (a).

Reference numeral 11 is an upper electrode substrate on which an upper transparent electrode and an alignment film are formed, 12 is a lower electrode substrate on which a lower transparent electrode and an alignment film are formed, 50 is a liquid crystal layer, and 1 is an upper electrode substrate 11 and a lower electrode substrate. A spherical spacer 52, which is provided between the upper electrode substrate 11 and the lower electrode substrate 12 and is provided around the edge of the upper electrode substrate 11 and the lower electrode substrate 12, is provided between the upper electrode substrate 11 and the lower electrode substrate 12. A sealing material that seals between the substrates. In FIG. 1B, reference numeral 65 is a liquid crystal filling port existing in a part of the sealing material 52, and 66 is a sealing material for sealing the liquid crystal material sealed from the liquid crystal filling port 65.

Example 1 In this example, a cylindrical hard glass fiber, which is an inorganic material, was used as the material for the spacers, and a large number of these spacers were immersed in a 1 wt% polyoxyethylene nonylphenyl ether aqueous solution. After drying at 100 ° C. for 2 hours, a polyoxyethylene adduct of nonylphenyl ether, which is a nonionic surfactant, is applied to the surface of the spacer to form a dispersion, which is dispersed in Freon, and the dispersion is sprayed onto a glass. It was dispersed on the surface of the substrate. A liquid crystal display device using a glass substrate with an alignment film in which such spacers are dispersed was prepared and the display characteristics were evaluated. As a result, in the liquid crystal display element using the conventional spacer made of the same material as this embodiment and not coated with the nonionic surfactant, the defect rate due to static electricity was 5%.
In the liquid crystal display element according to this example, no defect due to static electricity occurred. The specific resistance of the spacer at this time is
It was 2 × 10 ¹⁰ Ω · cm when measured from the measured value of a hard glass plate of the same material treated in the same manner.

Example 2 A divinylbenzene-based cross-linked polymer, which is an organic material, was used as a material for the spacer, and after dipping in a 0.5 wt% aqueous solution of polyoxyethylene polyoxypropylene, 1
After drying at 00 ° C. for 2 hours, polyoxyethylene polyoxypropylene, which is a nonionic surfactant, was coated and formed on the surface of the spacer, and this was dispersed in Freon. A liquid crystal display element using such a spacer was produced and the display characteristics were evaluated. As a result, in the case of the liquid crystal display element using the conventional spacer made of the same material as this example and not coated with the nonionic surfactant, the defective rate due to static electricity was 9%, as compared with this example. In the liquid crystal display element according to the example, the defective rate due to static electricity was 1% or less, and the defective rate could be reduced by 8%. The specific resistance of the spacer at this time was 5 × 10 ⁹ Ω · cm as measured from the measured value of the resin plate of the same material treated in the same manner.

Example 3 A divinylbenzene-based crosslinked polymer, which is an organic material, was used as a spacer material, and polyoxyethylene polyoxypropylene was kneaded into the divinylbenzene-based crosslinked polymer to prepare a spacer. A liquid crystal display element using such a spacer was produced and the display characteristics were evaluated. as a result,
In the liquid crystal display device using the conventional spacer made of the same divinylbenzene-based cross-linked polymer as in the present example and containing no nonionic surfactant, the defective rate due to static electricity was 9%. In the liquid crystal display element according to this example, the defective rate due to static electricity was 1%, and the defective rate could be reduced by 8%. The specific resistance of the spacer at this time was 5 × 10 ⁹ Ω · cm as measured from the measured value of the resin plate of the same material treated in the same manner.

As described above, in the liquid crystal display device using the spacer of each of the above-described embodiments, the surface of the spacer 1 which defines the distance between the upper electrode substrate 11 and the lower electrode substrate 12 constituting the liquid crystal display element is nonionic. The specific resistance of the spacer 1 is set to 10 ⁹ to 10 ¹² Ω by applying a surfactant or kneading a nonionic surfactant into the material of the spacer 1.
It can be mass-produced and controlled to about cm. Therefore, since the spacer has a specific resistance of about 10 ⁹ to 10 ¹² Ω · cm, the specific resistance of the liquid crystal layer 50 existing around the spacer is lowered, and the driving characteristic of the liquid crystal by the low frequency voltage is deteriorated.
It is possible to solve the conventional problem that the display image quality is degraded. Further, since the specific resistance of the spacer 1 can be made close to the specific resistance of the liquid crystal material, the potential difference between the spacer 1 and the liquid crystal material can be reduced, and as a result, the flow charge amount when the liquid crystal material is sealed can be reduced. Therefore, the spacer 1 can be prevented from being charged. Further, the charges charged on the spacer 1 can be transferred into the liquid crystal material or the alignment film, and the charging can be prevented. Since the spacers 1 can be prevented from being charged in this manner, the conventional problems that the electric characteristics of the liquid crystal material become non-uniform, the optical characteristics of the liquid crystal display element change, and the display image quality deteriorates can be solved.
Further, since the static electricity of the spacer 1 is discharged, it is not necessary to perform the process of leaving the spacer 1 at a high temperature for a long time.

FIG. 2 shows an arrangement direction (for example, rubbing direction) of liquid crystal molecules on an electrode substrate, a twisting direction of liquid crystal molecules, and a polarization axis (or absorption) of a polarizing plate when the liquid crystal display element 62 according to the present invention is viewed from above. The (axial) direction and the optical axis direction of the member that brings about the birefringence effect are shown, and FIG. 3 is a perspective view of a main part of the liquid crystal display element 62 according to the present invention.

Twisting direction 10 of liquid crystal molecules and twist angle θ
Is a rubbing direction 6 of the alignment film 21 on the upper electrode substrate 11, a rubbing direction 7 of the alignment film 22 on the lower electrode substrate 12, and a positive dielectric anisotropy sandwiched between the upper electrode substrate 11 and the lower electrode substrate 12. It is defined by the type and amount of the optical rotatory substance added to the nematic liquid crystal layer 50 having the property.

In FIG. 3, in order to align the liquid crystal molecules between the two upper and lower electrode substrates 11 and 12 sandwiching the liquid crystal layer 50 so as to form a twisted spiral structure, a transparent upper layer made of, for example, glass is used. The rubbing method, which is a method of rubbing the surfaces of the alignment films 21 and 22 made of an organic polymer resin made of polyimide, for example, in contact with the liquid crystal on the lower electrode substrates 11 and 12 with a cloth in one direction, is used. ing. The rubbing direction at this time, that is, the rubbing direction, the rubbing direction 6 in the upper electrode substrate 11, and the rubbing direction 7 in the lower electrode substrate 12 are the alignment directions of the liquid crystal molecules. The two upper and lower electrode substrates 1 that have been oriented in this way
1 and 12 are made to face each other with a gap d ₁ so that the rubbing directions 6 and 7 intersect each other at approximately 180 to 360 degrees, and the two electrode substrates 11 and 12 are notched for injecting liquid crystal. When a nematic liquid crystal having a positive dielectric anisotropy and having a predetermined amount of an optical rotatory substance is sealed in by adhering with a frame-shaped sealant 52 having a portion 51,
The liquid crystal molecules have a helical molecular arrangement with a twist angle θ in the figure between the electrode substrates. Reference numerals 31 and 32 are transparent upper and lower electrodes made of, for example, indium oxide or ITO (Indium Tin Oxide). A member that produces a birefringence effect on the upper electrode substrate 11 of the liquid crystal cell 60 thus configured (hereinafter referred to as a birefringence member. Fujimura et al., "ST
N-LCD retardation film ", magazine electronic material 1991
(February issue, pages 37-41) 40, and upper and lower polarizing plates 15 and 16 with the member 40 and the liquid crystal cell 60 sandwiched therebetween.

The twist angle θ of the liquid crystal molecules in the liquid crystal 50 can take a value in the range of 180 ° to 360 °, but is preferably 200 ° to 300 °, but lighting in the vicinity of the threshold value of the transmittance-applied voltage curve. From the practical viewpoint of avoiding the phenomenon that the state becomes an orientation that scatters light and maintaining excellent time division characteristics, the range of 230 to 270 degrees is more preferable. This condition basically makes the response of the liquid crystal molecules to the voltage more sensitive and acts to realize excellent time division characteristics. In order to obtain excellent display quality and the refractive index anisotropy [Delta] n ₁ of the liquid crystal layer 50 a product [Delta] n ₁ of the thickness d ₁
-D ₁ is preferably set in the range of 0.5 μm to 1.0 μm, more preferably 0.6 μm to 0.9 μm.

The birefringent member 40 acts so as to modulate the polarization state of the light passing through the liquid crystal cell 60, and converts the liquid crystal cell 60 alone, which was capable of only colored display, into black and white display. Thus the birefringent member 40 refractive index anisotropy [Delta] n ₂ and is extremely important product [Delta] n ₂ · d ₂ of a thickness d _2, preferably 0.8μm from 0.4 .mu.m, more preferably 0.5μm To 0.7 μm.

Further, since the liquid crystal display element 62 according to the present invention utilizes the elliptically polarized light due to the birefringence, the polarizing plate 15,
When the uniaxial transparent birefringent plate is used as the birefringent member 40, the relationship between the 16 axes and the liquid crystal alignment directions 6 and 7 of the electrode substrates 11 and 12 of the liquid crystal cell 60 is extremely important. .

The function and effect of the above relationship will be described with reference to FIG. FIG. 2 shows an axis of a polarizing plate, an optical axis of a uniaxial transparent birefringent member when the liquid crystal display device having the configuration of FIG. 3 is viewed from above,
3 shows the relationship between the alignment directions of liquid crystal molecule axes of an electrode substrate of a liquid crystal cell.

In FIG. 3, 5 is the optical axis of the uniaxial transparent birefringent member 40, 6 is the alignment direction of the liquid crystal molecules of the birefringent member 40 and the upper electrode substrate 11 adjacent thereto, and 7 is the lower electrode substrate 12. The liquid crystal alignment direction, 8 is the absorption axis or polarization axis of the upper polarization plate 15, 9 is the absorption axis or polarization axis of the lower polarization plate 16, and the angle α is uniaxial birefringence with the liquid crystal alignment direction 6 of the upper electrode substrate 11. The angle β formed by the optical axis 5 of the member 40 is the angle formed by the absorption axis or polarization axis 8 of the upper polarizing plate 15 and the optical axis 5 of the uniaxial transparent birefringent member 40, and the angle γ is the lower polarizing plate 16. Is the angle between the absorption axis or polarization axis 9 of the liquid crystal and the liquid crystal alignment direction 7 of the lower electrode substrate 12.

Here, how to measure the angles α, β, and γ in this specification will be defined. In FIG. 7, the intersection angle between the optical axis 5 of the birefringent member 40 and the liquid crystal alignment direction 6 of the upper electrode substrate will be described as an example. The intersection angle between the optical axis 5 and the liquid crystal alignment direction 6 is shown in FIG.
As shown in FIG. ₂ , it can be represented by φ ₁ and φ ₂ , but in the present specification, the smaller corner of φ ₁ and φ ₂ is adopted. That is, since φ ₁ <φ ₂ in FIG. 7A, φ ₁ is the intersection angle α between the optical axis 5 and the liquid crystal alignment direction 6,
Since φ ₁ > φ ₂ in FIG. 7B, φ ₂ is defined as an intersection angle α between the optical axis 5 and the liquid crystal alignment direction 6. Of course, either one may be adopted when φ ₁ = φ ₂ .

In the liquid crystal display device according to the present invention, the angles α, β and γ are extremely important.

The angle α is preferably 50 ° to 90 °, more preferably 70 ° to 90 °, the angle β is preferably 20 ° to 70 °, more preferably 30 ° to 60 °, and the angle γ is preferably. It is desirable to set each to 0 to 70 degrees, and more preferably to 0 to 50 degrees.

If the twist angle θ of the liquid crystal layer 50 of the liquid crystal cell 60 is in the range of 180 ° to 360 °, the above angle is satisfied regardless of whether the twist direction 10 is clockwise or counterclockwise. α, β, and γ may be within the above range.

In FIG. 3, the birefringent member 40 is disposed between the upper polarizing plate 15 and the upper electrode substrate 11, but instead of this position, the lower electrode substrate 12 and the lower polarizing plate 16 are provided.
It may be disposed between and. This case corresponds to the case where the entire configuration of FIG. 3 is inverted.

Example 1 The basic structure is the same as that shown in FIGS.
In FIG. 4, the twist angle θ of the liquid crystal molecules is 240 degrees, and as the uniaxial transparent birefringent member 40, a liquid crystal cell having a parallel orientation (homogeneous orientation), that is, a twist angle of 0 degree was used. Here, the ratio d / p of the thickness d (μm) of the liquid crystal layer and the helical pitch p (μm) of the liquid crystal material added with the optical rotatory substance was set to 0.67. The alignment films 21 and 22 were formed of a polyimide resin film and used after being rubbed. The alignment film that has been subjected to this rubbing treatment tilts the liquid crystal molecules that are in contact with the alignment film with respect to the substrate surface with a tilt angle (p
The retilt angle) is 4 degrees. The uniaxial transparent birefringent member 4
Δn ₂ · d ₂ of 0 is about 0.6 μm. On the other hand, Δn ₁ · d ₁ of the liquid crystal layer 50 having a structure in which liquid crystal molecules are twisted by 240 degrees is about 0.8 μm.

At this time, by setting the angle α to about 90 degrees, the angle β to about 30 degrees, and the angle γ to about 30 degrees, the voltage applied to the liquid crystal layer 50 via the upper and lower electrodes 31 and 32 is increased. When the voltage is below the threshold value, light non-transmission, that is, black display, and when the voltage exceeds a threshold value, light transmission, that is, white and black display, can be realized. In addition, the axis of the lower polarizing plate 16 is 50
When rotated 90 degrees from 90 degrees, white display was realized when the voltage applied to the liquid crystal layer 50 was below the threshold value, and black when the voltage was above the threshold value, which was the reverse of the above.

FIG. 5 shows a change in contrast at the time of time division driving at 1/200 duty when the angle α is changed in the configuration of FIG. Although the contrast was extremely high when the angle α was in the vicinity of 90 degrees, the contrast decreased as the angle deviated. Moreover, when the angle α is small, both the lighting part and the non-lighting part are bluish, and when the angle α is large, the non-lighting part is purple and the lighting part is yellow, and in any case black and white display is impossible. Similar results are obtained for the angle β and the angle γ, but in the case of the angle γ, as described above, when the image is rotated from 50 degrees to 90 degrees, the black and white display is reversed.

Example 2 The basic structure is the same as that of Example 1. However, the liquid crystal layer 50
The liquid crystal molecule has a twist angle of 260 degrees, and Δn ₁ · d ₁ is about 0.
The difference is 65 μm to 0.75 μm. Δ of the parallel alignment liquid crystal layer used as the uniaxial transparent birefringent member 40
n ₂ · d ₂ is about 0.58 μm as in the first embodiment. The ratio of the thickness d ₁ (μm) of the liquid crystal layer to the helical pitch p (μm) of the nematic liquid crystal material to which the optically active substance is added is d / p =
It was set to 0.72.

At this time, by setting the angle α to about 100 degrees, the angle β to about 35 degrees, and the angle γ to about 15 degrees, the monochrome display similar to that of the first embodiment can be realized. It is also similar to the first embodiment in that a reverse black-and-white display is possible by rotating the axial position of the lower polarizing plate from the above value by 50 to 90 degrees. The tendency for the deviations of the angles α, β, and γ is almost the same as that of the first embodiment.

In each of the above embodiments, a parallel alignment liquid crystal cell having no twist of liquid crystal molecules was used as the uniaxial transparent birefringent member 40, but rather a liquid crystal layer having twisted liquid crystal molecules of about 20 to 60 degrees is used. There is less color change depending on the angle. Like the above-mentioned liquid crystal layer 50, this twisted liquid crystal layer is formed by sandwiching liquid crystal between a pair of transparent substrates that have been subjected to the alignment treatment so that the alignment treatment directions intersect a predetermined twist angle. It In this case, the bisected angle of the two orientation treatment directions sandwiching the twisted structure of the liquid crystal molecules may be treated as the optical axis of the birefringent member. A transparent polymer film may be used as the birefringent member 40 (uniaxially stretched film is preferable at this time). In this case, PET (polyethylene terephthalate), acrylic resin film and polycarbonate are effective as the polymer film.

Further, although the single birefringent member is used in the above embodiments, in addition to the birefringent member 40 in FIG. 3, another birefringent member is provided between the lower electrode substrate 12 and the lower polarizing plate 16. It is also possible to insert a bending member. In this case, Δn ₂ · d ₂ of these birefringent members should be readjusted.

Example 3 The basic structure is the same as in Example 1. However, as shown in FIG. 8, the red, green, and blue color filters 3 are provided on the upper electrode substrate 11.
By providing the light shielding film 33D between the filters 3R, 33G, 33B and the filters, multicolor display is possible.

In FIG. 8, each filter 33
On the R, 33G, 33B and the light shielding film 33D, a smoothing layer 23 made of an insulating material is formed in order to reduce the influence of these irregularities, and then an upper electrode 31 and an alignment film 21 are formed.

Example 4 A liquid crystal display module 63 in which a liquid crystal display element 62 according to Example 3, a drive circuit for driving the liquid crystal display element 62, and a light source are compactly integrated.

FIG. 9 shows an exploded perspective view thereof.
The IC 34 for driving the liquid crystal display element 62 is mounted on a frame-shaped printed board 35 having a window portion for fitting the liquid crystal display element 62 in the center. The printed circuit board 35 in which the liquid crystal display element 62 is fitted is fitted in the window portion of the frame-shaped body 42 formed by plastic molding, the metal frame 41 is overlapped on this, and the claws 43 are formed on the frame-shaped body 42. The frame 41 is fixed to the frame-like body 42 by bending it inside the notch 44.

A cold cathode fluorescent lamp 36 disposed at the upper and lower ends of the liquid crystal display element 62, a light guide 37 made of an acrylic plate for uniformly irradiating the liquid crystal display cell 60 with light from the cold cathode fluorescent lamp 36, A reflecting plate 38 formed by applying white paint to a metal plate and a milky white diffusing plate 39 for diffusing light from the light guide 37 are fitted into the window portion from the back side of the frame-shaped body 42 in the order of FIG. Be done. An inverter power supply circuit (not shown) for turning on the cold cathode fluorescent lamp 36 is provided with a recess (not shown) provided on the right side rear portion of the frame-shaped body 42. The recess 45 of the reflector 38 is provided.
It is in a position facing. ). Diffusion plate 39,
The light guide 37, the cold cathode fluorescent lamp 36, and the reflector 38 are fixed by bending a tongue piece 46 provided on the reflector 38 into an edge 47 provided on the frame-shaped body 42.

Embodiment 5 The liquid crystal display module 63 according to Embodiment 4 is used in the display section of a laptop personal computer.

FIG. 10 shows a block diagram thereof, and FIG. 11 shows a diagram mounted on the laptop personal computer 64.
The result calculated by the microprocessor 49 is to drive the liquid crystal display module 63 by the drive IC 34 via the control LSI 48.

As described above, according to the above-described embodiment, it is possible to realize the field effect liquid crystal display device which has excellent time-division driving characteristics and which enables monochrome and multicolor display.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. . For example, in the above-described embodiment, an example in which the present invention is applied to a simple matrix type liquid crystal display device is shown, but it goes without saying that the present invention can also be applied to an active matrix type liquid crystal display device using a TFT or the like.

[0052]

As described above, according to the present invention,
Since spacer charging can be prevented without lowering the specific resistance of the liquid crystal material, the display image quality of the liquid crystal display device can be improved.

[Brief description of drawings]

1A is a cross-sectional view of a liquid crystal display element according to an embodiment of the present invention, and FIG. 1B is a plan view of the liquid crystal display element shown in FIG.

FIG. 2 is an explanatory view showing a relationship among an alignment direction of liquid crystal molecules, a twisting direction of liquid crystal molecules, an axis direction of a polarizing plate, and an optical axis of a birefringent member in a first embodiment of a liquid crystal display device according to the present invention. Is.

FIG. 3 is an exploded perspective view of a main part of the first embodiment of the liquid crystal display element according to the present invention.

FIG. 4 is an explanatory diagram showing the relationship between the twist direction of liquid crystal molecules, the direction of the axis of the deflecting plate, and the optical axis of the birefringent member in the second embodiment of the liquid crystal display device according to the present invention.

FIG. 5 is a graph showing contrast and transmitted light color-crossing angle α characteristics of the first embodiment of the liquid crystal display device according to the present invention.

FIG. 6 is an explanatory view showing a relationship among an alignment direction of liquid crystal molecules, a twisting direction of liquid crystal molecules, a direction of an axis of a deflecting plate, and an optical axis of a birefringent member in a liquid crystal display device according to a third embodiment of the present invention. Is.

FIG. 7 is a diagram for explaining how to measure intersection angles α, β, and γ.

FIG. 8 is a partially cutaway perspective view of an upper electrode substrate portion of an embodiment of the liquid crystal display device according to the present invention.

FIG. 9 is an exploded perspective view of a liquid crystal display module according to the present invention.

FIG. 10 is a block diagram of an embodiment of a laptop computer according to the present invention.

FIG. 11 is a perspective view of an embodiment of a laptop computer according to the present invention.

[Explanation of symbols]

1 ... Spacer, 11 ... Upper electrode substrate, 12 ... Lower electrode substrate,
50 ... Liquid crystal layer, 52 ... Sealing material, 65 ... Liquid crystal filling port, 6
6 ... Sealing material.

Claims (1)

[Claims] 1. Two transparent substrates are superposed at a predetermined interval via a number of spacers so that the surfaces of the two transparent substrates on which the transparent pixel electrodes are provided face each other, and the space between the two substrates is superposed. In a liquid crystal display device having a liquid crystal display element in which a liquid crystal is sealed, a nonionic surfactant is applied to the surface of the spacer, or a nonionic surfactant is kneaded into the material of the spacer. A liquid crystal display device characterized by the above.