JPS62153821A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To reduce very much the dependency of contrast upon visual angle by setting the twist angle of liquid crystal molecules to 200-270 deg. and setting the angle between the rubbing direction of a front substrate and the axis of transmission of a polarizing plate and that between axes of transmission of front and rear polarizing plates to 0-60 deg.. CONSTITUTION:Two glass substrates 1 and 2, which are subjected to the orienting treatment by rubbing to have <=5 deg. tilt angle and 200-270 deg. twist angle, are allowed to face each other with such minute gap between them that a product DELTAn.d between a thickness (d) of a liquid crystal layer 8 and a refractive index anisotropy DELTAn of the liquid crystal is 0.8-1.0mum. A nematic liquid crystal to which chiral materials having an optimum concentration are added is charged into a cell to arrange molecules at 200-270 deg. twist angle. Polarizing plates 9 and 10 are stuck to front and rear faces of the cell so that the angle between their axes of transmission is 0-60 deg. and the angle between the rubbing direction of the front substrate and the axis of transmission of the polarizing plate stuck to the rear face is 0-60 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a liquid crystal display element used for high time division drive dot matrix display and the like.

[Prior Art] Liquid crystal display elements with 90°T N array hills are widely used in various fields. This 90°TN array cell is located at the center of the cell as shown in Figure 4! ! Angle relative to x (or y) is ±4
The rubbing direction is the 5° direction, and the rubbing direction for the front board and front board is arrow a1 for the front and arrow a2 for the back.
> is returned by approximately 90 degrees. Further, the polarizing plate is attached so that its polarization axis substantially coincides with the rubbing direction. Note that a very small amount of chiral material is contained in the liquid crystal cell to prevent reverse twist.

Since this liquid crystal display element performs display by controlling the transmission and blocking of light using the optical rotation of the liquid crystal cell, the contrast has a large viewing angle dependence and the contrast from the front is low.

Additionally, there are drawbacks such as the back color being gray and dull, and the viewing angle being narrow.

In addition, the angle formed by the rubbing direction of the front substrate and the back substrate is set to be greater than 90° and smaller than 180°, and the included angle of the polarization axes of the front and back sides of the polarizing plate is 0° to 90°,
There are some that are attached so that the included angle with the rubbing direction is 0° to 60'', but both the contrast ratio and the viewing angle are poor.

[Object of the invention] The object of the present invention is to reduce the viewing angle dependence of contrast,
It is an object of the present invention to provide a liquid crystal display element that has good contrast when viewed from the front, has a wide viewing angle, and is capable of high time division driving.

[Summary of the Invention] The present invention is characterized in that a transparent electrode and an alignment layer are formed on a surface that becomes an inward surface, and furthermore, the tilt angle is 5° or less, and the tilt angle is 180＠ or less.
Two glass substrates that have been subjected to alignment treatment by rubbing so that the twist angle is in the range of 270 degrees are , aμ
They are made to face each other at a minute interval of TrL~1,0TrLμ and their peripheral edges are glued with a sealant to form a hill, and a nematic liquid crystal added with an optimum concentration of chiral substance is injected into this cell to form a cell with a range of 180° to 270°. While the molecular alignment state is such that the torsion angle of The polarization axis or the absorption axis of the polarization axis is affixed in increments of 0° to 60'', and is characterized by: 1. The viewing angle dependence of contrast is small, the contrast ratio is large, and the contrast from the front is high. Also, it is possible to perform good display, and high display quality and high time division driving are also possible.

[Example] Figures 1 to 3 show an example of the present invention, in which transparent electrodes 3.4 and alignment layers 5, 6 are formed on the inward surfaces of two glass substrates 1, 2, Furthermore, the required orientation layer 1! l! (described later), both substrates 1.2 are placed facing each other at a required minute interval, and their peripheral edges are adhered with a sealant 7 to form a cell, and a nematic liquid crystal 8 doped with a chiral substance is placed inside this hill.
I'm alone. This liquid crystal 8 has a molecular alignment having a twist angle within a range of 180° or more and 210° or less between the front substrate 1 and the rear substrate 2 by an alignment process described later. Polarizing plates 9 and 10 are pasted on the front and rear surfaces of the cell so that the included angle of the polarization axis (or absorption axis) and the included angle with the rubbing direction during alignment treatment have a predetermined relationship (v&description). ing.

The orientation treatment is performed as follows. That is, the alignment layer 5
．． 6 so that the tilt angle is as low as 5° or less. As shown in Figure 1, the rubbing direction is from the upper left to the lower right of the front l plate 1 side C. ;10° to IX
in a direction forming an angle of 45° from (arrow b1), rear substrate 2
In g1II, the direction is from the lower left to the upper right at an angle of 10° to 45° with respect to the center line X (arrow b2> is the reference point,
When one of them is selected, the other is rotated by the required twist angle by 16 degrees.Thereby, the liquid crystal 8 is rotated to the left by a twist angle in the range of 180 degrees to 270 degrees between both substrates 1 degree. It becomes a rotating molecular arrangement.

On the other hand, the polarizing plate 10 on the rear side has an included angle between its polarization axis (or absorption axis) C2 (FIGS. 1 and 2) and the rubbing direction (arrow b1) in the alignment layer 5 on the inner surface of the front substrate 1. Paste it so that it is 60" from Oo, and attach the polarizing plate 9 on the front side.
is attached so that the included angle between its polarization axis (or absorption axis) C1 (FIG. 2) and the polarization axis (or absorption axis) C2 of the polarizing plate 10 on the back side is 60'' from Oo.

Note that the thickness d of the liquid crystal layer is set to a value such that the product Δn−d with the refractive index anisotropy Δn of the liquid crystal 8 is 0.8 μm to 1.0 μm. Further, the chiral substance added to prevent intermediate state and reverse twist is 0.5 to 1. OIm% (
Pitch = 1 um/10 @ε11%
) is added so that δ;

The liquid crystal display element having the above configuration has a yellow mode due to interference color due to birefringence when no electric field is applied, and a dark blue pattern is displayed on a yellow back m when an electric field is applied.

This display has a vivid appearance and high display quality.

In addition, if the twist angle is less than 180°, the contrast ratio will be small, and if it is larger than 210", it will be difficult to prevent the occurrence of an intermediate state when the alignment layer is aligned by normal rubbing, so the comprehensive evaluation The angle ranges from 180° to 270°.

[Effects of the Invention] As described above, according to the present invention, the twist angle of the liquid crystal between both door plates is in the range of 180° to 270°, and the rubbing direction on the front substrate side and the polarization axis of the polarizing plate or The included angle between the absorption axis and the polarization axis or the absorption axis of the front and rear polarizing plates is set in the range of 00 to 60°, and the chiral substance is added at an optimal concentration to prevent intermediate states and reverse twists from occurring in the liquid crystal. Therefore, when compared at the same duty ratio as a display element using a 90° TN array cell, the dependence of the contrast on the viewing angle is extremely small, the contrast ratio is large, and the contrast from the front is also good. Moreover, it has a wide viewing angle, and high time division driving is also possible. Also, Δ
Since the thickness of the liquid crystal layer is set such that n-d is 0.8 μm to 1.0 μm, display with the best image quality can be performed.
Together with the vivid display achieved by the combination of the background color and pattern display color, the display quality can be improved. Furthermore, 5
Since the tilt angle is extremely low, such as less than 1, a special alignment treatment method is not required, and the desired alignment can be achieved by ordinary rubbing.

[Brief explanation of drawings]

1 and 2 show the rubbing directions of the front and rear substrates, the polarization axis phase n1 of the polarizing plate, and the relationship between the polarization axis of the polarizing plate and the rubbing direction in an embodiment of the liquid crystal display element according to the present invention. 1. Explanation Figure 3 is a sectional view of the same example, and Figure 4 is a 90°
The relationship between the front side of the IN array cell and the rubbing direction on the front side is shown 1
It is an explanatory diagram. 1 and 2... Glass substrate 3 and 4... Transparent electrode 5
and 6...Alignment layer 8...Liquid crystals added with chiral substance 9 and 10...Polarizing plate bl...Rubbing direction b2 on the front substrate side...Rubbing direction C1 on the back substrate side...Front surface Polarizing axis C2 of side polarizing plate... Polarizing axis of rear polarizing plate Procedure correction April 1988 288 1. Indication of the case 1985 Special request No. 297163 2. Name of the invention Liquid crystal display element 3. Relationship to famous case to be amended Applicant Name (230) Stanley Electric Co., Ltd. 10
Agent address: 1-1-5 Minami-Aoyama-chome, Minato-ku, Tokyo Date of amendment order (self-initiated) (1 sending date) Showa year, month, day 6, ^11 Positive anti-staining issue 1 Scope of claims, ／・っ≧
, 7. Contents of amendment (1) The scope of claims is amended as shown in the attached sheet. (2) [Polarization axis] on page 2, line 12 of the specification is corrected to "transmission axis." (3) Same, third negative line “180°1 to r 200’
Correct it as j. (4) Correct the "polarization axis" in the 4th stroke of the same page to "transmission axis J." (5) Correct "180°" in the 16th line of the same page to "200°"
I am corrected. (6) "1.0mμ" on the 19th line of the same page is rl, 0μ
Correct it to ml. (7) Same, page 4, line 3, “180°” is changed to “200°”
I am corrected. (8) In the 5th line of the same page, change the “polarization axis or absorption axis” to “
"Transmission axis" is corrected. (9) In the same page, lines 6 to 7, "polarization axis or absorption axis of both polarizing plates" is corrected to "transmission axis J of the back polarizing plate." (10) In the same page, line 2, on page 5, correct "180°" j 200
(11) Correct the polarization axis (or absorption axis) in lines 4 to 5 of the same page as "its transmission axis j. (12) Correct the line 18 of the same page. of [180” J to “200”
Correct it as °j. (13) Same page, line 20, correct "its polarization axis" and "its transmission axis". (14) Same as above, delete "(or absorption axis)" in the first line of page 6. (15) In the same page, line 4 to line 6, [the polarization axis (or ... polarization axis (or absorption axis)] is defined as "the transmission axis c1 (Fig. 2) and the polarization on the back side. "Transmission axis of plate 10"
I am corrected. 6) Same page, lines 11 to 12, “0.5 to 1.0
(17) Correct “180°” on the 19th line of the same page to r200°.
Correct it as j. (18) Same, page 7, line 3, “180°” is f 200
” Corrected as J. (19) In the same page, on the 6th line, “180°” is changed to 7200.”
Correct it as j. (20) Same page, lines 7 to 9, the polarizing axis of the polarizing plate.
...or the "absorption axis" should be corrected as "the included angle with the transmission axis of the polarizing plate, the transmission axis j of the front and back polarizing plates." (21) "Polarizing plate" in page 8, line 8 of (22) In the same page, line 18, [Polarization of the front side polarizer] shaft"
is corrected as [transmission of front polarizing plate @1. (23) Same page, line 19 [Polarizing axis of back side polarizing plate]
is corrected to be "transmission axis J of the front polarizing plate." In the above 2, a transparent electrode and an alignment layer are formed on the surface that is the facing surface within the scope of the claim, and the tilt angle is 5 degrees or less, and it is on the same level as Yu. Two glass substrates that have been subjected to an alignment treatment by rubbing so as to have a twist angle in the range of ~270° are prepared so that the product Δn−d of the thickness d of the liquid crystal layer and the refractive index anisotropy Δn of the liquid crystal is 0. .8
A cell is formed by facing each other at a minute interval of μTy 1 to 1,0 μTy, and bonding the peripheral edges with a sealant.A nematic liquid crystal containing an optimal concentration of chiral substance is injected into this cell, and a 200° to 270° While the molecular alignment state has a twist angle within a range, polarizing plates are placed on the front and back sides of the cell, and the included angles of these 111 are from 0° to 60°, and the rubbing direction on the front substrate side and the transmission axis of the 1st polarizing plate A liquid crystal display element characterized in that the liquid crystal display element is attached so that an included angle between the liquid crystal display element and the liquid crystal display element is 0° to 60°.

Claims (1)

[Claims] A transparent electrode and an alignment layer are formed on the inward facing surface, and the two sheets are aligned by rubbing so that the tilt angle is 5 degrees or less and the twist angle is in the range of 180 degrees to 270 degrees. The product Δn・d of the thickness d of the liquid crystal layer and the refractive index anisotropy Δn of the liquid crystal is 0.8 μm to 1.0.
A cell is formed by facing each other at a minute interval of mμ and bonding the peripheral edges with a sealant.A nematic liquid crystal added with an optimum concentration of chiral substance is injected into this cell to form a 180° to 2
While the molecules are arranged in a state with a twist angle in the range of 70°, polarizing plates are placed on the front and back sides of the cell, and the angle between the polarization axes or absorption axes is between 0° and 60°, and the rubbing direction on the front substrate side is The included angle with the polarization axis or absorption axis of both polarizing plates is 0°
A liquid crystal display element characterized in that it is attached at an angle of ~60°.