JPS5918784A - Color liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain titled display device with reduced red displaying component, capable of giving genuinely black display, by the use, as a component of a dichromatic dye mixed composition, of a black liquid crystal material containing a specific dye with its maximum light absorption corresponding to a visible ray wavelength longer than a given value. CONSTITUTION:The objective display can be obtained by the use, as a component of a dichromatic dye mixed composition, of a black liquid crystal material containing pref. at least two specific dye of formula (n, l, m, and x are each integer >=1 or 0) with its (those) maximum light absorption(s) corresponding to visible ray wavelength(s) longer than 660mmu (e.g. an anthraquinone-based dichromatic dye with its maximum absorption corresponding to a wavelength of 701mmu).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a color liquid crystal display device using a black liquid crystal material containing a dichroic dye mixture composition.

[Prior art and its problems]

A liquid crystal display device using a black liquid crystal material in which a dichroic dye mixture composition is dissolved is generally well known because it has the feature of being able to perform color switching by applying a voltage. In a color liquid crystal display device applied to such a system, the displayed color and its brightness are mostly determined by the dye of the dichroic dye mixture composition dissolved in the liquid crystal.

As is clear from the above, since the color tone and sharpness of the display are determined by the dichroic dye mixture composition, a pure black dye is particularly preferred as the dye used for this type of display. In this case, since it is not possible to obtain a pure black display using the conventionally known dyes mentioned above, at present, it is reluctantly possible to obtain a pure black color by mixing and combining yellow, red, colored dyes, etc. It is configured so that a black display appears. However, in liquid crystal materials for black display using the mixture combination described in 1., it is difficult to display pure black, and the display contains other visible light.
(, ti degree is often lacking.

Since the visible light has a particularly large red display component, it is necessary to improve the visibility by removing or reducing this component.

[Purpose of the invention]

The present invention uses a dichroic dye mixture composition mentioned above, reduces the red display component generated by this composition and which tends to negate the purpose of the present invention, and uses a liquid crystal display material that can display pure color. The purpose of the present invention is to provide a liquid crystal display device.

[Summary of the invention]

The present invention is a color liquid crystal display device having a black liquid crystal panel that is capable of displaying near pure black using a dichroic dye mixture composition, and which displays a visible light display accompanying the mixing of the dichroic dye mixture. It is characterized by absorbing as much as possible the red component of 660 mμ or more among the components, and sufficiently suppressing the appearance of this red component.

That is, in order to obtain black light or black color by mixing various dichroic dyes, one or more of the above dyes having maximum absorption capacity in the "1" visual light range at 660 mμ or more is used. It is to mix multiple 4ilts. For example, it is possible to absorb components such as red light by mixing an anthraquinone dichroic dye with an absorption thickness of 701 mμ into a conventionally known dichroic dye composition. However, depending on the application, if the red light component is to be avoided, a pure black display can be easily achieved by mixing multiple types of dichroic dyes that have the absorption maximum of 660 mμ or more and have the ability to absorb the red light component. A dye is obtained. this is,
Dichroic dyes that have the ability to absorb in this type of wavelength range have a solubility point (extremely low solubility) with liquid crystals, so it is common to use substances that have absorption maximum in the same wavelength range. By intentionally using a plurality of two or more types (this is one feature of the present invention), sufficient absorption capacity can be exhibited.

Therefore, it is preferable to use dichroic dyes whose absorption maximums are in the visible light region of 660 mμ or more. For example, the first
The absorption maximum wavelengths of the anthraquinones according to the present invention shown in the table are 701 mμ, 690 mμ, 683 mμ, and 41 mμ.
By mixing the dye i1, further mixing this mixed dye with other two-color dye mixture composition, and mixing and dissolving this in liquid crystal, a color liquid crystal device exhibiting pure black color can be produced. It is possible.

Figure 1 shows the 5'C absorption curve (b) of a color liquid crystal device made by dissolving a conventionally known dichromatic dye mixture composition in liquid crystal.
According to the present invention, a liquid crystal material is prepared by mixing an anthraquinone dye having an extremely thick absorption wavelength of approximately 701, 690, 683, and 674 mp with this dichroic dye mixture composition and dissolving it in liquid crystal. The light absorption curve of the color liquid crystal device is shown in (a).

As is clear from this figure, in the color liquid crystal device according to the present invention, there is a significant difference in the wavelength range of 660 mμ or more in the visible light range, and it is clear that the light absorption of the red component is extremely large. This makes it possible to achieve pure black display.

Table 1 shows the dichroic dyed rice f11 according to the present invention, which has a maximum wavelength absorption in the visible light range of 660 mμ or more.

Table 1 [Effects of the Invention] As is clear from the above and the characteristic curves (,) in Fig. 1, by using the mixture of dichromatic dyes according to the present invention, a black color can be obtained, and the purity of the black color can be improved. It has the feature of reducing other colors that appear, especially the red component, which is currently a problem, or reducing it to a level that is almost imperceptible to the eye.

Therefore, if a color liquid crystal device is formed using a black liquid crystal material in which such a dye is dissolved and mixed, extremely clear display can be achieved.

[Embodiments of the invention]? phenylcyclohexane ZI, T-
1 (i94 (manufactured by Merck & Co.), a dichroic dye mixture (azo type and anthraquinone type), a G dye (Table 1) whose maximum wavelength absorption is about 701 mμ, and a dye whose maximum wavelength absorption is about 690 mμ F dye (Table 1), same (68
E dye located at 3 mμ (Table 1), and the same maximum is approximately 674
A liquid crystal material for pyroelectric display was prepared by mixing 0.5% by weight of mμ I dyes (Table 1), and a color liquid crystal display device was constructed using this liquid crystal material. As is clear from the above, the display wavelength characteristic of this display device is shown by the curve (a) in Figure 1.
It shows an absorption spectrum equivalent to that of the red light emitting component, which was a particular problem, and efficiently absorbs it, so there is almost no red display wavelength range, and it is barely perceptible to the human eye.This is because pure black display cannot be achieved. It tastes like crab.

In addition, it is particularly effective to use a large number of dyes that have an extremely thick absorption wavelength of 660 + nμ or more of the above-mentioned dichroic dyes.
As mentioned above, it is possible to increase the effect even by increasing the number of types of coffins.

Note that the objects of the present invention can be achieved by any combination of the dichroic dyes in Table 1. Therefore, it is a good idea to limit the amount and mix various things. This is because this type of dye has a problem with solubility in the product (however, the dyes in Table 1 have relatively better solubility than known dyes), and if a large number of dyes are used, the necessary amount of mixing and addition will be applied to each dye. This is because since the absorption can be shared, a sufficient amount of absorption can be maintained, and efficiency is improved.

In the above examples, a part of the two-color dye mixture composition was explained, but the combinations thereof are free, and the two-color (iL dye) composition according to the present invention is not limited to those in Table 1. Furthermore, liquid crystal materials are similarly not limited to phenylcyclohexane-based liquid crystals, but include biphenyl-based liquid crystals, phenylcyclohexanoate-based liquid crystals, phenylbenzoate-based liquid crystals, Schiff base-based liquid crystals, and pyrimidine-based liquid crystals. A type of liquid crystal and oxazole liquid crystal or'
Several types of ML may be used.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining the absorption spectrum of the liquid crystal compound according to the present invention in the visible light region. (7317) Agent: Patent attorney Kensuke Norichika (and 1 other person) 1. The number of people who threaten the US and the U.S. (q people)

Claims (1)

[Claims] (1) Dichroic dye T1 (In a color crystallization display device using a black liquid crystal material having a composition of 1, as a component of the dichroic dye mixture composition, the maximum wavelength absorption is in the visible light region of 660 mμ or more. A color liquid crystal display device characterized by containing a dye having the following chemical structural formula tJNH2Nil (where " + iHmHX > an integer of 1 or zero)"
(2) In the claim set forth in item 1, the dichroic dye mixed composition contains at least two kinds of dyes having wavelength absorption maximums in the visible light range of 660 mμ or more as components. color liquid crystal display device.