JPH03132624A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain the display which is relatively wide in the visual angle of the display, is high in contrast and is easily visible over a wide range by disposing a circular polarizing plate on the upper side of the liquid crystal cell constituted by sealing a PC type liquid crystal into a space and a reverse rotational circularly polariz ing plate on the lower side. CONSTITUTION:This liquid crystal element ha the liquid crystal cell 16 constituted by sealing the PC type liquid crystal into the space, the counterclockwise or clockwise circularly polarizing plate 17 disposed on the upper side of this liquid crystal cell 16 and the clockwise or counterclockwise circular polarizing plate 18 disposed on the lower side thereof. The molecular arrangement of the liquid crystal 15 attains a perpendicularly arrayed state and the circularly polarized light transmitted through the circular polarizing plate 18 from below transmits the inside of the liquid crystal cell 16 as it is and, therefore, this light cannot transmit the upper circularly polarizing plate 17 and is eventually shut off. The part of the white display around the black display is consequently the circularly polarized light effectively transmitted through the liquid crystal cell 16. The high contrast is obtd. in such a manner and the visual angle at which the display can be visually recognized is relatively widened. The display which is easily visible over the wide range of the visual angles is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a liquid crystal display element having a wide viewing angle for displaying a display and high contrast so that the display is easy to see.

[Conventional technology]

2. Description of the Related Art Conventionally, a black mask type TN type liquid crystal display element having a structure as shown in FIG. 2, for example, is known as a liquid crystal display element.

That is, the liquid crystal display element 1 includes transparent electrodes 3, 3° each having a predetermined pattern on the opposing inner surfaces of substrates 2.2'' made of a transparent material such as glass substrates arranged parallel to each other.
Furthermore, an alignment film (not shown) is formed on the opposing inner surfaces of each substrate 2, 2' from above each transparent electrode 3, 3 so as to have a predetermined alignment direction, and the base F
i2'' is provided with a black mask 4 for defining the outline of a display pattern on the inner surface of the cell 6, and a TN type liquid crystal 5 is injected into the space between the two substrates 2 and 2'' and sealed, thereby forming a liquid crystal cell 6. , and polarizing plates 7 and 8 are disposed above and below the liquid crystal cell 6.

When the liquid crystal display device 1 configured in this way is off,
The molecules of the liquid crystal 5 in the liquid crystal cell 6 are arranged in a twisted state based on the alignment direction of the inner surfaces of the substrates 2, 2, and light from below passes through the polarizing plate and enters the liquid crystal cell 6. incident,
The light rotates along the molecular arrangement of the liquid crystal in this liquid crystal cell 6,
The light is emitted from the liquid crystal cell 6 and transmitted through the polarizing plate 7, resulting in a white display.

In addition, when on, the molecules of the liquid crystal 5 in the liquid crystal cell 6 are aligned almost vertically in the pattern portion formed by the transparent electrodes 3, 3°, so that the polarizing plate 8 is exposed from below.
The light that passes through the liquid crystal cell 6 and enters the liquid crystal cell 6 passes through the liquid crystal cell 6 without being rotated, and at that time, the light is polarized in the direction of the absorption axis of the polarizing plate 7. Since the light is blocked by the polarizing plate 7, a black display is performed in the pattern portion.

[Problem to be solved by the invention]

However, the liquid crystal display element 1 having such a configuration has a relatively narrow viewing angle that allows the display to be viewed when it is on.
Outside this viewing angle range, the display becomes difficult to see, and even within this viewing angle range, the contrast of the display is not very high, so there is a problem that the visibility of the display is not very good.

In view of the above points, the present invention provides a relatively wide display viewing angle,
Moreover, it is an object of the present invention to provide a liquid crystal display element that has high display contrast and can provide an easy-to-see display over a wide viewing angle range.

[Means to solve the problem]

According to the present invention, the present invention provides a liquid crystal cell configured by sealing a PC type liquid crystal in a space constituted by two glass substrates arranged in parallel with each other at an interval; This is achieved by a liquid crystal display element comprising a counterclockwise or clockwise circularly polarizing plate disposed above the cell and a clockwise or counterclockwise circularly polarizing plate disposed below the liquid crystal cell. Ru.

[For production]

According to this invention, when the liquid crystal cell is off, the molecular arrangement of the liquid crystal in the liquid crystal cell is in a so-called focal conic state on the inner surface of the substrate constituting the liquid crystal cell, and light from below first passes through the circularly polarizing plate below. By transmitting the light, it becomes clockwise or counterclockwise circularly polarized light and then enters the liquid crystal cell.
The incident light is effectively transmitted through the liquid crystal. and,
This circularly polarized light is scattered by liquid crystal molecules, emitted upward from the liquid crystal cell, and transmitted through the circularly polarizing plate above, thereby producing a white display.

In addition, when it is on, the molecules of the liquid crystal are arranged vertically, so the circularly polarized light that passes through the circularly polarizing plate from below passes through the liquid crystal cell as it is, so it can pass through the circularly polarizing plate above. It will be cut off. Therefore, a black display is performed, and the white display area around the black display is circularly polarized light that has effectively passed through the liquid crystal cell, so high contrast is obtained and the viewing angle at which the display can be viewed is widened. It will be relatively wide.

〔Example〕

Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows an embodiment of a liquid crystal display element according to the present invention.

The liquid crystal display element 11 includes transparent electrodes 13.13 each having a predetermined pattern on the opposing inner surfaces of substrates 12.12 made of a transparent material such as glass substrates arranged parallel to each other.
Further, an alignment film (not shown) formed from above each transparent electrode 1313' to have a predetermined alignment direction is provided on the opposing inner surface of each of the substrates 12 and 12', and the substrate A liquid crystal cell is formed by injecting a PC-type liquid crystal 15 into the space between the two substrates 12 and 12 and sealing the space between the two substrates 12 and 12. 16, and circularly polarizing plates 17 and 18 are arranged above and below this liquid crystal cell 16.

The circularly polarizing plate 17 is a clockwise circularly polarizing plate, and the circularly polarizing plate 18 is a counterclockwise circularly polarizing plate, each of which is constructed by combining a linearly polarizing plate with a quarter wavelength plate, for example. obtain.

The liquid crystal display element 11 according to the present invention is constructed as described above, and its operation will be explained next.

First, when off, the liquid crystal 15 is in a so-called focal conic state, and in this state, light that enters the liquid crystal display element 11 from below in the vertical direction in FIG.
Depending on the weather, the light becomes counterclockwise circularly polarized light, enters the liquid crystal cell 16, and is scattered by hitting molecules of the liquid crystal 15 in the liquid crystal cell 16, resulting in not only counterclockwise circularly polarized light but also various types of polarized light. and is ejected above the liquid crystal cell 16. Therefore, only the clockwise circularly polarized light is transmitted through the circularly polarizing plate 17 above the liquid crystal cell 16, resulting in a white display.

Furthermore, when on, the liquid crystals 15 are arranged in a line substantially perpendicular to the substrate 12, 12'. In this state, light that enters the liquid crystal display element 11 from below in the vertical direction in FIG. It will pass through the inside as it is. Therefore, the light is reliably blocked by the circularly polarizing plate 17 above the liquid crystal cell 16, and thus a black display is performed. Therefore, since the periphery of the black display pattern is a white display using clockwise circularly polarized light, the viewing angle at which the display can be visually recognized is relatively wide, and the contrast is also high.

In the above embodiment, the upper circularly polarizing plate 17 is a clockwise circularly polarizing plate, and the lower circularly polarizing plate 18 is a counterclockwise circularly polarizing plate, but the present invention is not limited to this. It is clear that similar effects can be obtained even if the upper circularly polarizing plate 17 is a counterclockwise circularly polarizing plate and the lower circularly polarizing plate 18 is a clockwise circularly polarizing plate.

〔Effect of the invention〕

As described above, according to the present invention, when the liquid crystal cell is off, the molecular arrangement of the liquid crystal in the liquid crystal cell is in a so-called focal conic state on the inner surface of the substrate constituting this liquid crystal cell, so that light from below is first directed downward. By passing through the circularly polarizing plate, the light becomes clockwise or counterclockwise circularly polarized, and then enters the liquid crystal cell.The incident light effectively passes through the liquid crystal, and this circularly polarized light is polarized by liquid crystal molecules. By being scattered, the light is emitted upward from the liquid crystal cell, and is transmitted through the circularly polarizing plate above, resulting in a white display.

In addition, when it is on, the molecules of the liquid crystal are arranged vertically, so the circularly polarized light that passes through the circularly polarizing plate from below passes through the liquid crystal cell as it is, so it can pass through the circularly polarizing plate above. As a result, a black display is performed, and in the white display area around the black display, the circularly polarized light has effectively passed through the liquid crystal cell, so high contrast is obtained and the display is The visible viewing angle becomes relatively wide.

Thus, according to the present invention, there is provided an extremely excellent liquid crystal display element that has a relatively wide viewing angle at which the display can be visually recognized, and that also has high display contrast to provide an easy-to-see display over a wide viewing angle range. You will get it.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of one embodiment of a liquid crystal display element according to the present invention. FIG. 2 is a schematic cross-sectional view showing an example of a conventional liquid crystal display element. 11...Liquid crystal display element; 12.12'...Glass substrate, 13.13°...Transparent electrode; 14...Black mask; 15...Liquid crystal; 16...Liquid crystal cell: 17. 18...Circular polarizing plate.

Claims (1)

[Claims] (1) A liquid crystal cell configured by enclosing a PC type liquid crystal in a space formed by two glass substrates arranged parallel to each other at an interval, and a liquid crystal cell arranged above the liquid crystal cell. A liquid crystal display element comprising: a counterclockwise or clockwise circularly polarizing plate; and a clockwise or counterclockwise circularly polarizing plate disposed below the liquid crystal cell.