JPH05100213A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To allow multiplex driving by drastically decreasing the hysteresis of the transmittance-impressed voltage curve of the high-polymer dispersed liquid crystal display element. CONSTITUTION:This high-polymer dispersed liquid crystal display element is constituted by crimping a layer which is formed by allowing a light transparent resin 12 and a liquid crystal compsn. 13 having positive dielectric constant anisotropy to coexist and forming the liquid crystal 13 like water drops in the resin 12 or continuously forming the liquid crystal in the resin or a layer which is formed by circulating above-mentioned resin like wire meshes in the liquid crystal between a pair of electrodes X and Y. This display element is so constituted that the ratio d/p attains 0.003<=d/p<=0.1 when the diameter of the water drop-like spaces formed by the resin 12 or the spaces formed by the wire meshes of the resin is designated as d and the spiral pitch of the liquid crystal compsn. 13 as p.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A light-scattering type liquid crystal display device is a liquid crystal display device which controls transmission and scattering of light by changing the arrangement of liquid crystal molecules. These elements include a heat writing type liquid crystal display element in which the alignment of liquid crystal molecules is changed by heat and voltage, and a polymer dispersion type liquid crystal display element in which the alignment of liquid crystal molecules is changed by voltage. The polymer dispersed liquid crystal display device has a structure in which a liquid crystal substance is dispersed in a polymer substance or a structure in which a polymer substance is dispersed in a liquid crystal substance.

For example, NCAP (Society, Fore, Information, Display, International, Symposium, SID'85 Digest, 68 (1985)) and PDLC (Polymer Dimer) in which nematic liquid crystal is microencapsulated.
A spersed LCD (Journal, Of, Applied, Physics, J.Appl.Phys. 60 , 2142 (1986)) has been announced. These devices have a structure in which liquid crystals in the form of water droplets are dispersed in a translucent polymer substance, and when no voltage is applied, the alignment of liquid crystal molecules in the water droplets is Due to the interaction, it takes a roughly irregular array. At this time, since there is a difference between the refractive index of the polymer and the refractive index of the liquid crystal, the incident light is scattered. When a voltage is applied to this, in the molecular alignment of the liquid crystal, the long axes of the liquid crystal molecules are aligned in the direction of the electric field. Light If substantially coincides with the refractive index of the liquid crystal (refractive index of ordinary light n _o) a polymer refractive index of at this time is transmitted.

As another example, a liquid crystal display device PN- having a structure in which a polymer is circulated in a liquid crystal material like a three-dimensional mesh.
LCD (Polymer Network LCD 15th LCD Symposium 2B
12,2B13 (1989)). It is said that this operation principle is different from the scattering / transparent switching based on the difference between the refractive index of the polymer and the refractive index of the liquid crystal as described above, but when no voltage is applied, the light scattering intensity is liquid crystal refractive index anisotropy [Delta] n - when (refractive index of extraordinary light n _e index of refraction of the ordinary n _o) is large, high when a large degree of randomness of the [Delta] n. Further, when a voltage is applied, the light transmittance increases when the order of Δn is increased.

In these liquid crystal display devices, in general, in order to increase the degree of light scattering, the particle size of the liquid crystal capsules in water droplets or the size of the three-dimensional mesh of the resin is 1 to 2 μm.
It is controlled to a certain degree. This is because if the average void is too large, the number of times of light scattering is small, and if it is too small, it approaches the wavelength of visible light, so that light scattering is suppressed.

In general, the change of light transmittance with respect to the applied voltage of these liquid crystal display elements (transmittance-applied voltage curve)
Has a so-called hysteresis, which is different when the voltage is increased and when it is decreased. The transmittance-applied voltage curve does not follow the same locus when the voltage is increased from 0 volt to V volt and when the voltage is continuously decreased from V volt to 0 volt, and draws a hysteresis curve.

When the liquid crystal display device is driven in a time-division manner (multiplex drive), the transmittance-applied voltage curve decreases when the voltage increases in order to operate as expected. It is premised that the same trajectory is followed in each case. When driving a liquid crystal display device that has a large hysteresis in the transmittance-applied voltage curve, the ratio of the effective voltage of the drive voltage that specifies the ON pixel to the effective value voltage that specifies the OFF pixel is absorbed by the hysteresis voltage width. , A display in which the difference between the transmittance of the ON pixel and the transmittance of the OFF pixel cannot be obtained.
Therefore, it is difficult to multiplex drive a polymer dispersed liquid crystal display device having a large hysteresis in the transmittance-applied voltage curve.

[0008]

As described above, in the polymer-dispersed liquid crystal display device, since the transmittance-applied voltage curve has a large hysteresis, it is difficult to perform multiplex driving.

The present invention has been made in consideration of the above,
An object of the present invention is to provide a polymer-dispersed liquid crystal display device capable of multiplex driving by significantly reducing the hysteresis of the transmittance-applied voltage curve as described above.

[0010]

In the liquid crystal display device of the present invention, a transparent resin and a liquid crystal composition having a positive dielectric anisotropy are mixed between a pair of electrodes, and the liquid crystal is A liquid crystal display element in which the resin is in the form of water droplets, or the liquid crystal is continuously formed in the resin, or the liquid crystal is sandwiched between layers of the resin. In the above, when the diameter of the water droplet-like voids formed by the resin or the interval between the voids formed by the mesh of the resin is d and the spiral pitch of the liquid crystal composition is p, the ratio d / p is 0.003 ≦ d. It is characterized in that /p≦0.1.

In this case, the liquid crystal composition has a thickness of 10 μm to 30 μm.
It is more desirable that the resin has a spiral pitch of 0 μm and that the resin has a contact angle with the liquid crystal composition of 25 degrees or more.

[0012]

A liquid crystal display device having a layer in which a resin and a liquid crystal substance are mixed is sandwiched between a pair of electrodes, for example, a structure in which the liquid crystal is dispersed in the resin in the form of water droplets, or the resin is mixed in the liquid crystal. In a structure that stretches in a three-dimensional network, the liquid crystal is aligned by the alignment control ability of the resin surface, and normally the liquid crystal is disordered on the resin surface (for example, the long axis of the liquid crystal molecule is horizontal to the resin wall surface). , Its orientation is various).

FIG. 2 shows a structure in which a liquid crystal is dispersed in a resin in the form of water droplets. Transparent electrodes X on the two glass substrates 11 and 11,
Y is formed, and the liquid crystal composition 13 is formed in the resin 12 and the water-drop-shaped liquid crystal capsule formed therein in the gap arranged so that these transparent electrodes face each other. At this time, the alignment of the liquid crystal molecules 14 in the liquid crystal capsule is as shown in FIG.
The long axis of the molecule is horizontal to a and the orientations are various. Also, depending on the combination of resin and liquid crystal composition,
For example, as shown in FIG. 3 (b), the long axis of the molecules can be arranged substantially perpendicular to the resin wall surface 12a.

Consider a case in which after the liquid crystal molecule alignment is changed by an external stimulus such as an electric field, the external stimulus is removed and the liquid crystal is realigned. For example, when an electric field is applied to the transparent electrodes X and Y, the long axes of the liquid crystal molecules in the liquid crystal capsule 13 in the form of water drops are aligned perpendicular to the transparent electrodes as shown in FIG. Next, when the voltage is removed and the liquid crystal is returned to the initial alignment, the long axes of the liquid crystal molecules try to return to an alignment close to the initial alignment with respect to the resin wall surface, but defects occur in the disordered portions and alignment in which the directions are not aligned. It is considered that this is because the uniform alignment control force of the liquid crystal in the water droplet-shaped liquid crystal capsule is weak and the uniform alignment control force of the resin wall surface is weak.

Therefore, as a means for increasing the uniform alignment control force of the liquid crystal, a liquid crystal material is added with an optical rotatory substance so that the liquid crystal has a helical pitch. in this case,
As shown in FIG. 3C, it is possible to easily re-orient. This is because by giving the liquid crystal material a helical pitch and imparting a twisting force, the liquid crystal material is more likely to return to the original orderly arrangement as compared with the conventional rearrangement of the disordered arrangement. Giving the liquid crystal a helical pitch acts to reduce the hysteresis of the transmittance-applied voltage curve.

When the resin surface is preliminarily provided with the vertical alignment regulating force, the synergistic effect of the alignment regulating force of the resin surface and the twisting force applied to the liquid crystal, as shown in FIG. The hysteresis acts in the direction of further decreasing.

As described above, in order to reduce the hysteresis, it is more effective if the resin itself in contact with the liquid crystal has a vertical alignment property.

The contact angle is one of the criteria for expressing the surface condition of such a resin. In this case, the contact angle is a measure of the wetting between the resin and the liquid, and represents the degree to which the affinity of the liquid for the resin overcomes the surface tension. The larger the contact angle, the harder it is to wet, and the smaller the contact angle, the easier it is to wet.

The contact angle of the resin with respect to the liquid crystal is related to the alignment state of the liquid crystal, and the longer the contact angle of the resin with respect to the liquid crystal, the longer the major axis of the liquid crystal molecules tends to be aligned perpendicular to the resin substrate. On the contrary, when the contact angle of the resin with respect to the liquid crystal is small, the long axes of the liquid crystal molecules tend to be aligned horizontally with respect to the resin substrate. In this case, the directions of the long axes of the liquid crystal molecules are disordered in the plane of the resin substrate, but if the resin substrate is subjected to a rubbing orientation treatment, a horizontal alignment state in which the long axes of the liquid crystal molecules are aligned in the rubbing direction can be obtained.

As a concrete example, there is one in which the pretilt angle obtained when the resin-formed substrate is subjected to the rubbing orientation treatment is controlled by the contact angle of the resin substrate (Proceedings of the 13th Liquid Crystal Symposium, page 13). Described in). As described above, the vertical alignment regulating force of the resin surface on the liquid crystal is associated with the contact angle of the resin surface on the liquid crystal.

In the polymer dispersion type liquid crystal display device in which the liquid crystal has an initial orientation of the liquid crystal, the liquid crystal is more likely to be formed than in the case where the resin has a small contact angle with respect to the liquid crystal in view of the orientation of the resin to the liquid crystal. A resin with a large contact angle that facilitates vertical alignment is better, and the contact angle of the resin with the liquid crystal is 2
It was experimentally found that the hysteresis of the transmittance-applied voltage curve is further reduced when the angle is 5 degrees or more.

An attempt to give the liquid crystal a helical pitch has been reported, for example, on page 11 of the 142nd Joint Research Committee Material (2.11.29-30) of the Japan Society for the Promotion of Science, Organic Materials for Information Science. According to these, from the viewpoint of increasing the contrast ratio and decreasing the response speed, it is said that the spiral pitch is set to 1 μm to 3 μm in order to avoid coloring due to selective reflection and to form a focal conic structure. .. However, in this case, the hysteresis is significantly increased.

The present inventors have conducted various experiments to find that d / p
It was found that the hysteresis width is significantly reduced when is 0.003 to 0.1. The spiral pitch is preferably 10 μm to 300 μm. d / p is 0.00
If it is less than 3, the twisting alignment force of the liquid crystal is too weak to control rearrangement in a disordered arrangement, and the hysteresis width is almost the same as in the case where there is no pitch. When d / p is larger than 0.1, a focal conic structure or the like is formed as described above, and PC (Phase-
Change) The hysteresis width is significantly increased as in the phase transition mode liquid crystal display device.

The contact angle θ of the resin with respect to the liquid crystal is 25 degrees to 18 degrees so that the initial alignment regulating force can reach 10 parts.
It is desirable to set it in the 0 degree range.

[0025]

EXAMPLES Examples of the present invention will be described below.

[Embodiment 1] FIG. 1 is a view showing that the present invention is applied to a multiplex driving liquid crystal display element, and a liquid crystal display panel 10 has a plurality of scanning lines Y (Y1 Y2).
Y3 ... YN) and plural signal lines X (X1 X2 X3 ... XM)
And are arranged to face each other in a matrix, and
The scanning line Y and the signal line X are connected to the scanning line electrode driving unit 20 and the signal line electrode driving unit 30, respectively. Scan line electrode driver
The signal line electrode drive unit 20 and the signal line electrode drive unit 30 output the voltage supplied from the drive voltage generation circuit 50 to the liquid crystal display panel 10 based on the signal from the control unit 40.

The liquid crystal display panel 10 is, as shown in FIG.
A structure in which liquid crystal is dispersed in a resin in the form of water droplets, and transparent electrodes X and Y are formed on two glass substrates 11 and 11, respectively,
A transparent resin 12 and a liquid crystal composition 13 in the form of water droplets, that is, in the form of a liquid crystal capsule, are dispersed and formed in a gap arranged so that the pair of transparent electrodes X and Y are opposed to each other.

That is, the obtained polymer dispersion type liquid crystal display element has a layer in which a resin and a liquid crystal substance are mixed between two substrates 11 with electrodes. An ultraviolet curable resin (NOA65 manufactured by Norland Co.) was used as a resin constituting the mixture. The liquid crystal material is a cyanobiphenyl liquid crystal (E8 manufactured by Merck Limited) and an optical rotatory material (S- manufactured by E. Merck).
811) was used in an amount of 0.1% by weight. The helical pitch of the liquid crystal is 100 μm. The resin and liquid crystal were stirred at a weight ratio of 1: 1 at room temperature for 5 minutes. This is mixed with glass fiber with a diameter of about 20 μm and sandwiched between two substrates with electrodes to obtain a uniform cell thickness, which is then irradiated with UV light for 30 minutes at an irradiation intensity of 5 mW / cm ² to cure the UV curable resin. Thus, a liquid crystal display device was obtained. The liquid crystal display element has a structure in which liquid crystals are dispersed in a resin in the form of water droplets, the diameter is approximately 1 μm, and d / p is 0.01.

In order to obtain a transmittance-applied voltage curve, He-Ne laser light was made incident on this liquid crystal display element, and the transmittance was measured. The spot diameter of the light was 2 mm, and the transmitted laser light was detected by a photodiode located at a distance of 20 cm from the liquid crystal display element. This element showed a favorable scattering state with a transmittance of about 0.5% when no voltage was applied.

In FIG. 4, the applied voltage (AC 7
0Hz) is increased to 50V and gradually decreased from 50V to 0V, showing a transmittance-applied voltage curve.
The transmittance was about 80% (maximum transmittance) when a voltage of 50 V was applied. Here, the voltage at which the transmittance is half the maximum transmittance is Vup50 (when rising) and Vdown50 (when falling), and the difference between Vup50 and Vdown50 is the hysteresis magnitude ΔV.
It is defined as. In the case of this embodiment, Vup50 = 22V, Vdown50
= 21.2 V, the magnitude of hysteresis is ΔV = 0.
It showed a small value of 8V.

At this time, the contact angle θ of the resin with the liquid crystal was 15 degrees.

In the case of the multiplex drive waveform by the frame inversion method, the liquid crystal drive voltage is generated by the drive voltage generation circuit 50 and is composed of six potentials, as shown in FIG. 1 (a). For example, a circuit 50 as shown in FIG. 1B obtains drive voltages V0 to V5 in descending order of potential based on the power supply voltage Vc. The drive voltage waveforms of the scanning lines and the signal lines are obtained by combining these potentials. In Figure 5,
An example of a liquid crystal drive voltage waveform when designating an ON pixel is shown.

(A) is a drive waveform of the scanning line, V0 is a selection potential, V5 is a selection potential at the time of polarity reversal, V4 is a non-selection potential, and V1 is a non-potential selection potential at the time of polarity reversal.

(B) is a drive waveform of a signal line, V5 is a potential for designating an ON pixel, V0 is a potential for designating an ON pixel at the time of polarity inversion, V3 is a potential for designating an OFF pixel, and V2 is for a potential inversion. This is a potential that specifies an off pixel.

Therefore, the voltage waveform applied to the liquid crystal when designating the ON pixel is (c). Similarly, in FIG.
7A and 7B show voltage waveforms (c) applied to the liquid crystal when the off pixel is designated by the selection and non-selection potentials of (a) and (b).

In multiplex drive, FIG. 5 (c)
The maximum amplitude of the ON voltage waveform of (the magnitude of V0-V5) is generally called the liquid crystal drive voltage Vop, and other than V3-V4, V4-V5, V1
The magnitude of -V2, V0-V1 is called the bias voltage Vp, and these V3-V4, V4-V5, V1-V2, V0-V1 are usually set equal. Here, the ratio between the liquid crystal drive voltage Vop and the bias voltage Vb is also referred to as the bias ratio (Vop / Vb) and is represented by B.

Since the liquid crystal has a property of responding to the effective value of the applied voltage, the voltage waveforms of FIGS. 5C and 6C are generally expressed in terms of the ratio of the effective value voltage. .. That is, the effective voltage of the ON voltage waveform of FIG.
Assuming that the ratio of the effective voltage of the off-voltage waveform in (c) is M,
It is indicated that the larger M is, the higher the contrast ratio is likely to be obtained. According to a general calculation, the number of scanning lines driven by the bias ratio B is N, and when B is N ^1/2 +1, the magnitude of M has a maximum value, and M is ((N ^1/2 +1 ) / (N ^{1/ 2-}
1)) Take a size of ^1/2 . For example, the number of scan lines is 8
In the book, M is 1.45, which means that the voltage applied to the ON pixel is 1.45 times the applied voltage applied to the OFF pixel. When actually using such a driving method, the voltage ratio M In the range of, the liquid crystal display element must respond. When driving a liquid crystal display device having a large hysteresis in the transmittance-applied voltage curve, it is necessary that the voltage ratio M is not absorbed by the hysteresis voltage width ΔV.
Specifically, the case where the number of scanning lines is 8 will be described. When the voltage for OFF is set to 20V, for example, the voltage for ON is 1.45 times 29V, so that the magnitude of hysteresis ΔV is at least less than 9V. Must be Considering the contrast ratio, it is desirable that the voltage width of the hysteresis be close to 0V.

In the multiplex drive of this embodiment, the liquid crystal cell is the scanning line Y on the glass substrate 11 shown in FIG.
The number of electrodes is 16 and the number of electrodes of the signal line X is 128, and these electrode groups are arranged so as to face each other in a matrix.

This device has a bias ratio B = 5 and a liquid crystal drive voltage Vop = 75V (effective value voltage 1 applied to an off pixel).
When multiplex driving was performed at 8 V and an effective value voltage of 24 V applied to ON pixels and projection was performed on a screen, a good display with a contrast ratio of 8 was obtained for any display pattern.

That is, in the polymer-dispersed liquid crystal display device of this embodiment, there is almost no hysteresis, multiplexing is possible, and a high contrast ratio is obtained.

Comparative Example 1 Next, the manufacturing method of the liquid crystal display element was the same as in Example 1, except that the liquid crystal substance was a cyanobiphenyl liquid crystal (E8 manufactured by Merck Limited) and the optical rotatory substance S-811 (E). A liquid crystal display device was prepared without adding Merck. When this transmittance-applied voltage curve was measured, Vup50 = 22V, Vdown50 = 17.5V
The magnitude of hysteresis showed a large value of ΔV = 4.5V.

Comparative Example 2 Next, the manufacturing method of the liquid crystal display element was the same as in Example 1, except that the liquid crystal material was a cyanobiphenyl liquid crystal (E8 manufactured by Merck Limited) and the optical rotatory material S-811 (E). 0.02% by weight
A liquid crystal display device was prepared using the added material and the added material of 1.2% by weight. Liquid crystal spiral pitch is 50 each
0 μm and 8 μm, and d / p is 0.002, 0.
It is 13. When the transmittance-applied voltage curve was measured, the former was Vup50 = 22V and Vdown50 = 17.7V.
The magnitude of hysteresis was ΔV = 4.3V, the latter was Vup50 = 24V, Vdown50 = 20.0V, and the magnitude of hysteresis was a large value of ΔV = 4.0V.

[Embodiment 2] By a method of manufacturing a liquid crystal display element similar to that of Embodiment 1, an optical rotatory substance S-8 added to a liquid crystal material is used.
If the helical pitch of the liquid crystal is increased or decreased to 200, 30, or 13 μm by changing the amount of 11 to 0.05, 0.3, or 0.8% by weight, that is, if the d / p is increased or decreased to 0.005, 0.03, or 0.08, Δ
V is 1.2, 0.5, and 1.5 V respectively, and 0.003 to 0.1
The magnitude of hysteresis was small in the range of.

[Example 3] A liquid crystal display device similar to that of Example 1 except that 0.3% by weight of a general monobasic chromium complex FC-805 (manufactured by 3M Co.) as a vertical aligning agent was added to the resin. Was used. Cyanobiphenyl liquid crystal E8 (manufactured by Mercury Limited) was added to this resin as an optically active substance.
0.3% by weight of B-15 (manufactured by Merck Limited) was added at a weight ratio of 1: 1 and sandwiched between two substrates with electrodes to obtain a uniform cell thickness. Irradiation was performed to cure the ultraviolet curable resin to obtain a liquid crystal display element. At this time, the device has a structure in which liquid crystals are dispersed in the resin in the form of water droplets, the diameter of the water droplets is 2 to 3 μm, the helical pitch of the liquid crystals is about 50 μm, and d / p is 0.04 to 0.06. The contact angle θ of this resin with the liquid crystal was about 35 degrees.

In the case of this embodiment, Vup50 = 18.0V, V
down50 = 17.9V, the magnitude of hysteresis is ΔV
= 0.1V, which is a very small value.

[Embodiment 4] As in Embodiment 1, the polymer dispersed liquid crystal display device has a layer in which a resin and a liquid crystal substance are mixed between two substrates with electrodes. As a resin forming the mixture, an ultraviolet curable resin NOA65 (manufactured by Norland) was used. Liquid crystal substance is cyanobiphenyl liquid crystal E8
(Manufactured by Mel Limited) as an optically active substance, S-81
1 (manufactured by E. Merck) was used in an amount of 0.1% by weight. The helical pitch of the liquid crystal is 100 μm. The resin and the liquid crystal were mixed with a stirrer at a weight ratio of 1: 4 at room temperature for 5 minutes.
A glass fiber having a diameter of about 20 μm was mixed and sandwiched between two substrates with electrodes to obtain a uniform cell thickness, which was irradiated with ultraviolet rays for 30 minutes to cure the ultraviolet curable resin to obtain a liquid crystal display device. .. The obtained polymer-dispersed liquid crystal display element has a structure in which a resin is stretched in a liquid crystal like a mesh, and the interval d between the voids formed by the mesh is about 1 to 4 μm, and d / p is It is 0.01 to 0.04.

As in Example 1, the transmittance-applied voltage curve was measured when the applied voltage (AC 70 Hz) was gradually increased from 0 V to 50 V and gradually decreased from 50 V to 0 V. The transmittance was about 80% when a voltage of 50 V was applied. Here, the voltage at which the transmittance is half of the maximum transmittance is defined as Vup50 when the voltage increases and Vdown50 when the voltage decreases, and the difference between Vup50 and Vdown50 is defined as the hysteresis magnitude ΔV.

In the case of this embodiment, Vup50 = 19.5V, V
down50 = 19.0V, the magnitude of hysteresis is ΔV
= 0.5V, which is a very small value.

[Comparative Example 3] The liquid crystal display device was manufactured in the same manner as in Example 4, except that the liquid crystal substance was a cyanobiphenyl liquid crystal E8 (manufactured by Merck Limited) and the optical rotatory substance (S-811). The element was prepared without adding).

When the transmittance-applied voltage curve was measured, Vup50 = 26V, Vdown50 = 22.0V, and the magnitude of hysteresis was as large as ΔV = 4.0V.

Example 5 A liquid crystal display device similar to that of Example 4 was prepared by adding 0.4% by weight of a monobasic chromium complex FC-805 (manufactured by 3M Company) as a vertical aligning agent to a resin. Using. As the liquid crystal, a cyanobiphenyl liquid crystal (manufactured by Merck Limited) to which 0.5% by weight of cholesteryl nonanoate (manufactured by Chisso Corporation) was added as an optically active substance was used. The helical pitch of the liquid crystal is 70 μm.
The resin and the liquid crystal were mixed with a stirrer at a weight ratio of 1: 4 at room temperature for 5 minutes. This is mixed with glass fiber with a diameter of about 20 μm and sandwiched between two substrates with electrodes to obtain a uniform cell thickness,
This was irradiated with ultraviolet rays for 20 minutes to cure the ultraviolet curable resin to obtain a liquid crystal display element. The obtained polymer-dispersed liquid crystal display element has a structure in which a resin is stretched in a liquid crystal like a mesh, and the distance d between the voids formed by the mesh is approximately 3 to 5 μm, and d / p is It was 0.04 to 0.07. At this time, the contact angle θ of the resin with the liquid crystal is about 4
It was 0 degrees.

In the case of this embodiment, Vup50 = 17.5V, V
down50 = 17.4V, the magnitude of hysteresis is ΔV
= 0.1V, which is a very small value.

[0053]

According to the present invention, there is provided a voltage-controlled light-scattering liquid crystal display device in which the hysteresis of the transmittance-applied voltage curve of the polymer-dispersed liquid crystal display device is significantly reduced and multiplex driving is possible. be able to.

[0054]

[Detailed Description of Drawings]

[0055]

1A is a plan view showing an embodiment in which the present invention is applied to a multiplex drive liquid crystal display device, and FIG. 1B is a circuit diagram showing a drive power supply circuit.

[0056]

FIG. 2 is a sectional view conceptually showing a part of the display panel of FIG.

[0057]

3 (a), (b), (c), (d) and (e).
FIG. 4 is a diagram showing an alignment state of liquid crystal molecules on a resin surface.

[0058]

FIG. 4 is a diagram showing a transmittance-applied voltage curve of a liquid crystal display element.

[0059]

FIG. 5 is a diagram showing drive potentials (a) and (b) for multiplex drive, and a voltage waveform (c) applied to a liquid crystal when an ON pixel is designated.

[0060]

FIG. 6 is a diagram showing drive potentials (a) and (b) for multiplex drive and a voltage waveform (c) applied to liquid crystal when an off pixel is designated.

[0061]

[Explanation of symbols]

 10 ... Liquid crystal display panel, 11 ... Glass substrate, 12 ... Translucent resin, 13 ... Liquid crystal composition

Claims (3)

[Claims] 1. A translucent resin and a liquid crystal composition having a positive dielectric anisotropy are mixed between a pair of electrodes, and the liquid crystal is in the form of water droplets in the resin or the liquid crystal is In a liquid crystal display element in which a layer formed continuously in a resin or a layer formed by wrapping the resin like a mesh in the liquid crystal is sandwiched, a diameter of a water drop-like void formed by the resin or When the distance between the voids formed by the mesh of the resin is d and the spiral pitch of the liquid crystal composition is p, the ratio d / p is 0.003 ≦ d / p ≦ 0.1. Liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal composition has a spiral pitch of 10 μm to 300 μm. 3. The liquid crystal display element according to claim 1, wherein the resin has a contact angle of 25 degrees or more with the liquid crystal composition.