JPH0677121B2 - Liquid crystal display element - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid crystal display device using a dichroic dye-added liquid crystal for dual-frequency driving and capable of displaying the same pattern in either negative display or positive display. It is a thing.

[Object of the Invention] It is an object of the present invention to display the same pattern in either negative display or positive display, and various display such as positive display in one part of one liquid crystal cell and negative display in the other part. It is to provide a liquid crystal display device.

SUMMARY OF THE INVENTION In the present invention, a dichroic dye is added to a hybrid alignment cell in which one transparent substrate side is vertically aligned and the other transparent substrate side is horizontally aligned with a small tilt angle. It is characterized in that a liquid crystal for dual frequency driving is injected and a polarizing plate is attached to either of the front and rear surfaces of the cell so that the polarization direction thereof coincides with the horizontal alignment direction. When an AC voltage having a frequency with a positive value is applied, a negative display is obtained, and when an AC voltage with a frequency having a negative Δε is applied, a positive display is obtained.

[Embodiment] FIG. 1 shows an embodiment of the present invention, in which 1A and 1B are transparent substrates (for example, glass substrates), 2 is a dual-frequency driving liquid crystal,
3 is a dichroic dye and 4 is a polarizing plate. One transparent substrate 1A
Has a transparent electrode formed on its inward surface and is subjected to vertical alignment treatment. The other transparent substrate 1B is
A transparent electrode is formed on the inward surface, and horizontal alignment processing having a minute tilt angle is performed. A hybrid alignment cell is formed by these substrates 1A and 1B and a sealant (not shown), and a dual frequency driving liquid crystal 2 to which a dichroic dye 3 is added is injected therein. On one of the front and rear surfaces of the cell, for example, the substrate 1A side, a polarizing plate 4 is attached so that its polarization direction (arrow a1) matches the horizontal alignment direction.

The dual-frequency driving liquid crystal is one in which the dielectric anisotropy Δε has a positive or negative value depending on the frequency, as shown in FIG.

In this embodiment, the DMOAP (N, N-
A vertical alignment film made of dimethyl-N-octadecyl-3-aminopropyltrimethoxy chloride) is formed and subjected to vertical alignment treatment, and a horizontal alignment film made of polyimide or the like is formed on the inner surface of the lower transparent substrate 1B to perform horizontal alignment. A structure in which a liquid crystal 2 having a frequency dependence of a dielectric constant such as DS-004A manufactured by Roddick Co., in which black dichroic dye 3 manufactured by Nippon Senshoku Co., Ltd. is added in an amount of about 0.5 wt% is injected into a film-treated cell. Has become.

Next, the operation will be described with reference to FIGS. 2 to 6. When no voltage is applied, the liquid crystal 2 and the dye 3 are vertical in the vicinity of the vertically oriented substrate 1A as shown in FIG. It is horizontal in the vicinity. For this reason,
The display surface of the liquid crystal display element is lightly colored on the entire surface as shown in FIG. This is the background B on the display surface.

When an alternating voltage in the frequency range of Δε> 0 is applied to this dye, the liquid crystal 2 and the dye 3 become parallel to the electric field direction, that is, perpendicular to the substrates 1A and 1B, as shown in FIG. No light absorption. As a result, the display pattern P is displayed white on the background B, which is lightly colored, as shown in FIG. It is a so-called negative display.

Moreover, when an AC voltage in the frequency range of Δε <0 is applied to the device, the liquid crystal 2 and the dye 3 are arranged orthogonal to the direction of the electric field, that is, parallel to the surfaces of the substrates 1A and 1B as shown in FIG. Light absorption by the sex pigment 3 increases. As a result, as shown in FIG. 6, the display pattern P is displayed in the lightly colored background B.
Is displayed darkly colored. This is a so-called positive display.

It should be noted that the above description is for positive and negative inversion display of one pattern P. However, if a transparent electrode is formed on the display surface so as to obtain a plurality of display patterns, one part is negative display and the other part is positive display. A display mode such as display is realized.

[Effects of the Invention] As described above, according to the present invention, a dual-frequency driving liquid crystal added with a dichroic dye is injected into a hybrid alignment cell, and a polarizing plate is provided on either of the front and rear surfaces of the cell. Is attached so that it coincides with the horizontal orientation direction, and by applying an AC voltage of a frequency at which Δε is a positive or negative value, positive display and negative display of the same pattern can be performed, and It is possible to display various parts such as positive in one part of the surface and negative in the other part.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of a liquid crystal display element according to the present invention, FIGS. 2 and 3 are explanatory views of an arrangement state when a voltage is applied in the same embodiment, FIGS. 4 to 6 Is an explanatory view of a display state of the same embodiment, and FIG. 7 is a frequency of the liquid crystal for dual frequency drive ().
FIG. 6 is a characteristic diagram of dielectric anisotropy (Δε). 1A and 1B …… Transparent substrate 2 …… Liquid frequency driving liquid crystal 3 …… Dichroic dye 4 …… Polarizing plate, a1 …… Polarization direction B …… Background, P …… Display pattern

Claims (1)

[Claims] 1. A hybrid alignment cell in which a vertical alignment treatment is performed on one transparent substrate side and a horizontal alignment treatment having a minute tilt angle is performed on the other transparent substrate side, and a dichroic dye is added to the hybrid alignment cell for dual frequency driving. A liquid crystal display device comprising a liquid crystal injected and a polarizing plate attached to either of the front and back surfaces of the cell so that the polarization direction thereof coincides with the horizontal alignment direction.