JPH10274760A - Liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the torsion angle of a liq. crystal and to enhance contrast by specifying the ratio of the thickness of the liq. crystal as a layer to the natural pitch of the liq. crystal. SOLUTION: An upper electrode substrate 3 and a lower electrode substrate 4 are disposed at a prescribed interval with a spacer 5, a liq. crystal 6 is held between the substrates 3, 4 and the prescribed interval is kept by elastic resin bodies 7 to form a liq. crystal cell 2. This liq. crystal cell 2 is put between an upper polarizing plate 8 and a lower polarizing plate 9. An optical isomer may be interposed between the upper polarizing plate 8 and the upper electrode substrate 3. The elastic resin bodies 7 are made of a synthetic resin selected from among polystyrene, a butadiene polymer, polyurethane, a chloroprene polymer and a vinyl chloride-vinyl acetate copolymer. When the ratio of the thickness (d) of the liq. crystal 6 as a layer to the natural pitch (p) of the liq. crystal 6 is represented by d/p, the difference [Δ (d/p)] between d/p at -10 deg.C and d/p at +60 deg.C is regulated to 0.01-0.03.

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.

[0002]

2. Description of the Related Art A conventional super-twisted nematic liquid crystal display device has a ratio d / p of a liquid crystal layer thickness d to a specific pitch p.
Is related to the twist angle 液晶 of the liquid crystal, and the range in which the display device can operate normally without generating disclination lines or fingerprints is ψ / 360-／ <d.
/ P <ψ / 360... (A)
94224.

[0003]

However, the range of d / p is determined by the above equation (a) due to variations in the layer thickness d of the liquid crystal and the specific pitch p during manufacture, and fluctuations of d / p with respect to temperature changes. When the torsion angle of the liquid crystal increases, the range of d / p becomes extremely narrow. For this reason, in actual mass production, the twist angle of the liquid crystal was limited to about 230 degrees. Furthermore, the general formula

[0004]

(Equation 5)

The compound (3) represented by

[0006]

(Equation 6)

In the compound (4) represented by the formula (1), domains are easily generated, and the range of d / p is extremely narrow.
However, since the compounds (3) and (4) have large dielectric anisotropy, they are very effective materials for lowering the threshold voltage.

The present invention utilizes the compound (3) or the compound (4) to extend the applicable range of d / p, keep d / p constant with respect to temperature change, and obtain a twist angle of the liquid crystal of 240 ° or more. However, an object of the present invention is to provide a liquid crystal display device which can be mass-produced and can withstand use in a wide temperature range.

Further, by expanding the range of d / p,
It is an object of the present invention to stabilize mass production of a liquid crystal display device in which a twist angle of liquid crystal is from 180 degrees to 230 degrees, and to improve contrast as compared with the related art.

[0010]

In order to achieve the above object, a liquid crystal display of the present invention has the following arrangement. That is, a liquid crystal cell in which a nematic liquid crystal twisted in the range of 180 degrees to 360 degrees is sandwiched between a pair of electrode substrates arranged opposite to each other, and a pair of polarizing plates arranged on both sides of the liquid crystal cell. In the liquid crystal display device provided with, the elastic resin body is narrowed between the two electrode substrates, and the nematic liquid crystal has a general formula

[0011]

(Equation 7)

Compound (1) and / or general formula

[0013]

(Equation 8)

Wherein the total composition ratio of the compound (1) to the compound (2) is at least 20% by weight and

[0015]

(Equation 9)

Compound (3) and / or general formula

[0017]

(Equation 10)

A compound containing compound (4), wherein the total composition ratio of compound (3) and compound (4) is in the range of 5% by weight to 55% by weight.

Here, R- represents a linear alkyl group having 1 to 9 carbon atoms.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical example of the liquid crystal display device of the present invention has a structure as shown in FIG. The time-division driving circuit 1 includes a liquid crystal cell 2
, A liquid crystal cell 2 is driven. In the liquid crystal cell 2, an upper electrode substrate 3 and a lower electrode substrate 4 are separated from each other by a spacer 5 at a predetermined interval.
Are confined at predetermined intervals by the elastic resin body 7. The liquid crystal cell 2 is sandwiched between an upper polarizing plate 8 and a lower polarizing plate 9. An optically anisotropic body may be interposed between the upper polarizing plate 8 and the upper electrode substrate 3. Examples of the elastic resin body include those made of synthetic resin such as polystyrene, butadiene-based polymer, polyurethanes, chloroprene polymer, and vinyl chloride-vinyl acetate copolymer, and formed into a shape such as a sphere or a rod.

FIG. 3 shows a luminance characteristic of a super-twisted liquid crystal display device with respect to a vertical voltage. In the figure, the voltage at which the luminance becomes 10% is V ₁₀ 90%
Is defined as β = V ₁₀ / V ₉₀ , where V is the voltage at which V ₉₀ is obtained. Β indicates a value of 1 or more, and as it approaches 1, it indicates that the time-division driving characteristic is better.

As an index indicating a temperature change of a ratio d / p between the liquid crystal layer thickness d and the specific pitch p, d / p of -10 ° C.
And the difference between d / p at 60 ° C. is defined as △ (d / p). △
The larger the value of (d / p), the more likely it is that a disclination line, a fingerprint, or the like will occur in response to a temperature change, which will hinder normal operation.

In order to clarify the effect of the present invention, an embodiment of the present invention will be described in comparison with a conventional example.

COMPARATIVE EXAMPLE 1 As a comparative example, glass fibers were used in place of the elastic resin body 7 shown in FIG.

[0025]

[Table 1]

Comparative Example 2 In Comparative Example 1, the liquid crystal was changed to the composition shown in Table 2.

[0027]

[Table 2]

Example 1 In this example, the liquid crystal was made into the composition shown in Table 3.

[0029]

[Table 3]

Example 2 In this example, the liquid crystal was made into the composition shown in Table 4.

[0031]

[Table 4]

Example 3 In this example, the liquid crystal was made into the composition shown in Table 5.

[0033]

[Table 5]

Example 4 In this example, the liquid crystal was made into the composition shown in Table 6.

[0035]

[Table 6]

Example 5 In this example, the liquid crystal was made into the composition shown in Table 7.

[0037]

[Table 7]

Example 6 In this example, the liquid crystal was made into the composition shown in Table 8.

[0039]

[Table 8]

As described above, in Comparative Examples 1 and 2, and in Examples 1 to 6, the optically active agent S-811 (manufactured by Merck) was added and the twist angles of the liquid crystal were adjusted to 200, 250 and 300 degrees at room temperature. d / p, β value and △ (d / p)
Are shown in Tables 9 and 10 respectively. However, it is assumed that the absorption axes of the upper and lower polarizing plates are each shifted by 45 degrees from the rubbing directions of the adjacent electrode substrates. The product Δn · d of the optical anisotropy Δn of the liquid crystal and the layer thickness d of the liquid crystal is about 0.8 μm.
m to 0.9 μm.

[0041]

[Table 9]

[0042]

[Table 10]

[0043]

[Table 11]

As is clear from Table 9, Examples 1 to 6 have almost the same d / p range as Comparative Examples 1 and 2. Compound (3) and compound (4) are compound (1) and / or
Alternatively, the range of d / p could be expanded by adding compound (2).

Next, as is clear from Table 10, if the torsion angle is the same, each embodiment has a smaller β value than the comparative example and is excellent in time-division characteristics. That is, the contrast can be increased. Furthermore, as is clear from Table 11,
The temperature change of d / p is very small. For this reason, in Comparative Examples 1 and 2, a domain is generated at −10 ° C. at a twist angle of 250 °, whereas Examples 1 to 6 are in a range of −10 ° C. to 60 ° C. even at a twist angle of 300 °. No domain emergence was seen. This is because the natural pitch p of the liquid crystals of Examples 1 to 6 has a smaller temperature change than the comparative example, and the elastic resin body having a larger coefficient of thermal expansion than the glass fiber at a low temperature at which the natural pitch p becomes smaller shrinks significantly. This is probably because the layer thickness d of the liquid crystal was reduced and d / p was kept constant.

FIG. 2 shows the color change of the appearance color with respect to the temperature for Comparative Example 1 and Example 5. As is clear from FIG. 2, the color change of Example 5 with respect to the temperature is small. This was confirmed in other examples. The present invention not only keeps d / p constant, but also makes little change in appearance color.

[0047]

As described above, according to the present invention,
Since the range of d / p is kept constant over a wide temperature range, the twist angle of the liquid crystal can be increased, which is very effective in improving the contrast.

The twist angle of the liquid crystal is from 180 degrees to 23 degrees.
It is effective for stabilizing mass production up to 0 degrees.

Further, it is effective for reducing the color change of the appearance color in a wide temperature range.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of one embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a CIE chromaticity diagram showing a color change of an appearance color of one embodiment of the present invention and a conventional comparative example.

FIG. 3 is a diagram showing a luminance characteristic with respect to a voltage for explaining a conventional multiplex driving characteristic.

[Explanation of symbols]

 1 time division driving circuit 2 liquid crystal cell 3 4 electrode substrate 6 liquid crystal 7 elastic resin body 8 9 polarizing plate

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[Procedure amendment]

[Submission date] May 18, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

[Title of the Invention] Liquid crystal device

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claims

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[Correction contents]

[Claims]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010]

A liquid crystal device according to the present invention is a liquid crystal device having a liquid crystal cell in which a nematic liquid crystal twisted in the range of 200 to 300 degrees is sandwiched between a pair of substrates. Between the pair of substrates, an elastic resin body using a synthetic resin selected from polystyrene, butadiene polymer, polyurethanes, chloroprene polymer, and vinyl chloride-vinyl acetate copolymer is disposed, and the liquid crystal cell D / p at −10 ° C., where d / p is the ratio of the liquid crystal layer thickness d to the liquid crystal specific pitch p,
The difference Δ (d / p) from the d / p at ° C. is 0.01 to 0.03.

[Procedure amendment 4]

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[Correction target item name] 0025

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[0025]

[Table 1]

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[0027]

[Table 2]

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[0029]

[Table 3]

[Procedure amendment 7]

[Document name to be amended] Statement

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[0031]

[Table 4]

[Procedure amendment 8]

[Document name to be amended] Statement

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[0033]

[Table 5]

[Procedure amendment 9]

[Document name to be amended] Statement

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[0035]

[Table 6]

[Procedure amendment 10]

[Document name to be amended] Statement

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[0037]

[Table 7]

[Procedure amendment 11]

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[0039]

[Table 8]

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

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[0047]

As described above, in the liquid crystal device of the present invention, the polystyrene, butadiene polymer, polyurethane, chloroprene polymer, and vinyl chloride
An elastic resin body using a synthetic resin selected from vinyl acetate copolymer is disposed, and Δ (d / p) of the liquid crystal cell is
Since it is 0.01 or more and 0.03 or less, the twist angle of the liquid crystal can be increased, which is very effective in improving the contrast.

[Procedure amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction contents]

Further, it is possible to realize a liquid crystal device in which domains are not generated for a wide range of temperature change.

[Procedure amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction contents]

Further, it is possible to realize a liquid crystal device having a small color change with respect to a wide temperature change.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C09K 19/46 C09K 19/46 G02F 1/13 500 G02F 1/13 500

Claims (1)

[Claims] A first electrode substrate disposed between a pair of opposed electrode substrates;
In a liquid crystal display device comprising a liquid crystal cell sandwiching a nematic liquid crystal twisted in a range of 80 degrees to 360 degrees and a pair of polarizing plates disposed on both sides of the liquid crystal cell, the two electrodes The elastic resin body is narrowed between the substrates, and the nematic liquid crystal has a general formula: And / or a compound of the general formula (1) Wherein the total composition ratio of the compound (1) and the compound (2) is in the range of 20% by weight or more and the general formula: And / or a compound of the general formula (3) A liquid crystal display device comprising the compound (4), wherein the total composition ratio of the compound (3) and the compound (4) is in the range of 5 to 55% by weight. However, R- means a linear alkyl group having 1 to 9 carbon atoms.