JPS6015044B2 - LCD color display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal color display device that utilizes the guest-host effect and is capable of displaying colors only in display portions such as letters and numbers.

A liquid crystal color display device (GH type LCD) that utilizes the guest-host effect is produced by adding an appropriate amount of dichroic dye to the liquid crystal (host) and changing the alignment direction of the liquid crystal and dichroic dye by applying an electric field. , is a color display device that utilizes changes in light absorption characteristics caused by dichroic pigments.

The GH type LCD uses a nematic liquid crystal with positive dielectric anisotropy as the host, and is processed so that it is aligned parallel to the substrate in the absence of an electric field (hereinafter referred to as GH type LCD (1)); There is a method (hereinafter referred to as G-matrix LCD (0)) in which a nematic liquid crystal with negative dielectric anisotropy is used and is arranged perpendicularly to the substrate in the absence of an electric field.

The GH type LCD (1) is a "colorless display" because it is decolored when an electric field is applied and colored when no electric field is applied.

On the other hand, the GH type LCD (0) is a "color display" that is colored when an electric field is applied and decolored when no electric field is applied. In terms of display effects, ``display with colored display'' is much better than ``colorless display'' due to the stimulation that enters the eye. For this reason, the GH type LCD (b) is better as a display method.
It can be said that it is superior to type LCD (1). On the other hand, considering the manufacturing technology, GH type LCD (1) is better than GH type LC.
It has higher reliability than D(0).

In other words, as the parallel alignment processing technology required for the GH type LCD (1), there are highly reliable and practically used technologies such as the SiO oblique evaporation method, but for the GH type L
Although methods using surface alignment agents such as organic substances are known for the vertical alignment treatment required for CDs (b), there are still many problems with long-term stability, reactivity with liquid crystals, etc. left behind. As mentioned above, GH type LCD (0) and GH type LC
The two methods D have advantages and disadvantages in terms of display effect and manufacturing technology, and no method has been obtained that has good display effects and stable manufacturing technology.

However, the present invention is concerned with improving the GH type LCD by taking advantage of only the advantages of the above two methods and eliminating the disadvantages, and specifically, by using parallel alignment processing, which is an established technology,
It also realizes a "colored display" with excellent display effects.

Hereinafter, the present invention will be explained based on examples and drawings. Embodiment 1 FIGS. 1 and 2 show that the in-plane components parallel to the substrates in the alignment direction of the liquid crystal layer in the display area and the non-display area are mutually disposed on the upper and lower two substrates of the liquid crystal color display device according to the present invention. FIG. 3 is a cross-sectional view and a plan view of a GH type LCD processed to be orthogonal in an electric field-free state.

In the figure, numerals 1 and 2 are transparent electrodes, which in this example are ln203 adhesive films.

3 and 4 are two transparent substrates, 5a is a nematic liquid crystal having positive dielectric anisotropy, and 5b is a dichroic dye.

In this example, a mixture of liquid crystals having the structure [A] below was used as the liquid crystal 5a, and a red dye having the structure [B] below was used as the dichroic dye 5b. 6a, 6b, 7a, 7b
is an alignment treatment layer for determining the alignment direction of the liquid crystal in the absence of an electric field, and in this example, it was formed by SiO oblique evaporation.

8 is a polarizing plate.

FIGS. 3 and 4 show conventional GH type LCDs, and the structure of the present invention is different from that of the conventional type with alignment treatment layers 6a, 6b.
, 7a, 7b, and the alignment direction of the liquid crystal layer 5 in the display area a and the non-display area b determined thereby is characteristic.

That is, in the conventional format, the alignment treatment layers 6 and 7 have an in-plane component parallel to the substrate in the alignment direction of the liquid crystal layer 5 on the entire surface regardless of whether the display area a or the non-display area b is a polarizing plate. is formed to match the polarization direction of. On the other hand, in the present invention, the in-plane component parallel to the substrate in the alignment direction of the liquid crystal layer 5 in the display area a coincides with the polarization direction x of the polarizing plate, and the in-plane component of the liquid crystal layer 5 in the non-display area b is The alignment treatment layers 6a, 7a and 6b, 7b are different from each other in the display area a and the non-display area b so that the in-plane component parallel to the substrate in the alignment direction coincides with the direction y perpendicular to the polarization direction of the polarizing plate. has been applied. In a GH type LCD, a colored state occurs when the in-plane component parallel to the substrate in the alignment direction of the liquid crystal layer 5 matches the polarization direction of the polarizing plate.The conventional method of the G matrix type LCD (1) is as shown in Figure 4. While the entire surface is colored, G according to the present invention
In the H-type LCD, only the display section a is colored, as shown in FIG.

Next, FIGS. 5 and 6 show the GH type LCD of the present invention, and the seventh
8 and 8 show a cross-sectional view and a plan view of a conventional G matrix type LCD (1) in which an electric field is applied to the display section.

In the conventional method, as shown in FIGS. 7 and 8, the display section a
In the part where the electric field is applied, the liquid crystal layer 5 is aligned in the direction z perpendicular to the substrate and perpendicular to the polarization direction x of the light, resulting in a bleached state, but the non-display part b remains in the colored state because no electric field is applied. Yes, "display color loss" occurs. On the other hand, according to the present invention, as shown in FIGS. 5 and 6, in the display section a, the liquid crystal layer 5 is arranged in the direction z perpendicular to the substrate, and the polarization direction x of the light and However, in the non-display area b, the arrangement direction y of the liquid crystal layer 5 and the polarization direction z of the light are perpendicular to each other and the light is in a bleached state, resulting in "full bleaching". As mentioned above, in the GH type ratio D (1) of the follow-up method, "full coloring"
In contrast, the GH type LCD according to the present invention can have two states: ``display coloring'' and ``full-scale bleaching''.

From the above, in the GH type LCD according to the present invention, unnecessary display parts are bleached by applying an electric field, and necessary parts are left colored by no electric field application, thereby making it possible to display colored characters, etc. It is characterized by the following. Embodiment 2 FIGS. 9 and 10 show the liquid crystal color display device according to the present invention on the substrate on the polarizing plate 8 side, parallel to the substrate in the alignment direction of the liquid crystal layer 5 in the display area a and non-display area b. FIG. 4 is a cross-sectional view and a plan view of a GH type LCD in a no-electric field state, which is processed so that in-plane components are orthogonal to each other.

As shown in the figure, in the second embodiment, the liquid crystal layer 5 of the display area a is arranged on the substrate 4 having eight polarizing plates in a direction that corresponds to the polarization direction The light beams are arranged in the direction y perpendicular to the polarization direction.

It has a so-called twisted nematic structure (TN structure). When light polarized in the x direction by the polarizing plate 8 enters the liquid crystal layer 5 in such an electric fieldless state, the plane of polarization is rotated due to the TN structure. However, since the rotation of this plane of polarization always coincides with the rotation of the alignment direction of the liquid crystal layer, absorption by the dichroic dye 5b always occurs and the display area a becomes colored. On the other hand, in the non-display area b, since the polarization direction of the light and the alignment direction y of the liquid crystal layer are always perpendicular to each other, no absorption occurs and the area is in a bleached state.

That is, in the absence of an electric field, the display portion has a TN structure and the non-display portion has a parallel structure. The electric field application state corresponds to FIGS. 5 and 6, and the entire surface is bleached.

As described above, in the present Example 2, the same effects as in Example 1 can be obtained, and it is possible to display with a good display effect in which only an arbitrary display portion is colored.

In the second embodiment, the display portion has a TN structure and the non-display portion has a parallel structure, but the same effect can be obtained even if the display portion has a parallel structure and the non-display portion has a TN structure.

In other words, in the absence of an electric field, the display area is colored by aligning the polarization direction of the light with the alignment direction of the liquid crystal layer, while the non-display area has a colored state where the polarization direction of the light and the alignment direction of the liquid crystal layer are always aligned. By rotating them orthogonally, it is possible to achieve a bleached state. In the above explanation, the display area is an area that can be colored or bleached at will, and is usually a display area for characters, numbers, etc.

In the GH type LCD of the follower type, the display part coincides with the electrode facing part, but in the GH type LCD according to the present invention,
The two do not need to match, and the electrode facing portion may be large as long as it includes the display portion. Furthermore, the present invention is a transmission type,
Any reflective type can be applied, and if applied to a reflective type, it can also be applied to the field of digital watches, for example.

As described above, the GH type LCD according to the present invention can be used as a color display device using a conventional method without sacrificing any of the advantages of conventional methods such as low voltage, low power drive capability, wide viewing angle, and arbitrariness of color selection. The drawback of ``display area'' was that it was only possible to display color loss,
This solves manufacturing difficulties.

In other words, according to the present invention, a "display color display" that uses a highly reliable manufacturing technology and has good display effects.
is possible.

[Brief explanation of drawings]

1 and 2 are a cross-sectional view and a plan view thereof showing an embodiment of the liquid crystal color display device according to the present invention in a no-electric field state, and FIGS. 3 and 4 are guest-host type liquid crystal color display devices according to the conventional method. A cross-sectional view and a plan view showing the device in an electric field-free state; FIGS. 5 and 6 are a cross-sectional view and a plan view showing the electric field applied state;
7 and 8 are a sectional view and a plan view showing the electric field applied state, and FIGS. 9 and 10 are a sectional view and a plan view showing the no-electric field state of an embodiment of the liquid crystal color display device according to the present invention. It is. 1,2...Transparent electrode, 3,4...Transparent substrate, 5A...Liquid crystal, 5B...Dichroic dye, 5...
Liquid crystal layer, 6, 7...Alignment treatment layer, 8...Polarizing plate, a...Display area, b...Non-display area. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] 1. A transparent electrode and an alignment layer are provided on two substrates, at least one of the transparent electrodes is formed into a patterned electrode,
In the liquid crystal display device, which is configured as a display section for displaying information by the patterned electrodes and utilizes a guest/host effect using a nematic liquid crystal having a positive dielectric anisotropy with a dye added between the two substrates, The substrate has a structure in which, on at least one of the substrate surfaces, parallel components of the alignment direction of the liquid crystal molecules to the substrate are substantially orthogonal to each other in the display area and the non-display area due to the alignment layer, 1. A liquid crystal color display device comprising one polarizing plate having a polarization direction in the same direction as the alignment direction of liquid crystals in a display section.