JPH05127148A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To simplify the constitution of the liquid crystal display element and the producting process by allowing members having a UV cut function, a function to adhere both substrates and water resistance function to coexist in the binder of the thin film of a high-polymer dispersion type liquid crystal. CONSTITUTION:This high-polymer dispersion type liquid crystal display element is constituted by including the structure in which the thin film 10 of the high-polymer dispersion type liquid crystal formed by superposing an upper electrode plate 11 provided with upper transparent electrodes 13 and a lower electrode plate 12 provided with lower transparent electrodes 14 on each other in such a manner that the surfaces provided with the respective transparent electrodes 13, 14 to face each other and dispersing a liquid crystal 2 into the binder 1 consisting of a high-polymer material is held between the two substrates 11 and 12. At least one of the UV cut function, the function to adhere the two substrates 11, 12 and the water resistance function are imparted to the binder or the members having at least one of these functions are made to coexist in the binder 1. The UV cut function, the adhering function and the water resistance function, etc., are added to the binder in such a manner and the sealing by a transparent protective film and a sealing material after the incorporation of the UV cutting materials is saved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer-dispersed liquid crystal display device, and more particularly to a polymer-dispersed liquid crystal display device capable of simplifying the structure and manufacturing process.

[0002]

2. Description of the Related Art Recently, a polymer dispersion type liquid crystal display device in which a liquid crystal is dispersed in a polymer material has been actively developed. Usually, the upper and lower surfaces of a polymer-dispersed liquid crystal thin film having a thickness of about 5 to 10 μm are sandwiched by two transparent electrodes, and when no voltage is applied between these electrodes, light is scattered and it is opaque. (OFF state / light-off state) When light of appropriate voltage is applied, light is transmitted and becomes transparent (ON state / lighting state). By utilizing this characteristic, a reflective display element having a fixed display pattern can be realized similarly to a conventional liquid crystal display element. This polymer-dispersed liquid crystal display element has a wide viewing angle and is bright because it does not require a polarizing plate, which is required in conventional liquid crystal display elements, and since it is not necessary to arrange liquid crystal molecules regularly, No membrane required,
It has advantages such as Such a technique is described, for example, in US Pat. No. 4,435,047.

FIG. 2 is a partially exploded cross-sectional view of the main constituent members showing the structure of a conventional reflection type polymer dispersion type liquid crystal display device.

Reference numeral 10 is a polymer dispersed liquid crystal thin film obtained by dispersing liquid crystal in a binder made of a polymer material, 11 is an upper electrode substrate, 12 is a lower electrode substrate, 13 is an upper transparent electrode, 14
Is a lower transparent electrode, 15 is a sealing material, 16 is an upper protective film, 17
Is a lower protective film, 18 is a conductive paste material, 19 is a frame plate, 20
Is a display window, 21 is an upper transparent protective film, 22 is a reflector,
Reference numeral 23 is a lower cover film.

The polymer dispersed liquid crystal thin film 10 is sandwiched between an upper electrode substrate 11 and a lower electrode substrate 12. The upper electrode substrate 11 and the lower electrode substrate 13 are formed of a transparent glass plate or a plastic film. Upper electrode substrate 1
1. On the facing inner surface of the lower electrode substrate 12,
ITO (Indium-Tin-Oxid
e): An upper transparent electrode 13 and a lower transparent electrode 14 formed of a film are provided. Upper transparent electrode 13, lower transparent electrode 1
4 is patterned into a shape corresponding to the display pattern,
Through the wirings (not shown) connected to the upper transparent electrode 13 and the lower transparent electrode 14, they are electrically connected to an external connection pad (not shown) provided on the outer peripheral portion of the substrate.
These wirings and external connection pads are also formed in the same layer as a part of the transparent electrode. In the case of a liquid crystal display element displaying a fixed pattern, the lower transparent electrode 14 of the lower electrode substrate 12 is usually formed on the entire surface of the lower electrode substrate 12 without patterning.

A sealing material 15 is provided around the upper and lower substrates 11 and 13 (peripheral edges) to prevent water from entering the polymer dispersed liquid crystal thin film 10 and to bond the upper and lower substrates 11 and 13. There is. Further, in order to facilitate the connection of the lower transparent electrode 14 of the lower electrode substrate 12 to the outside, a conductive paste material 18 for electrically connecting the lower transparent electrode 14 to the upper transparent electrode 13 of the upper electrode substrate 11 is provided. It is provided. In addition, S is provided on the upper transparent electrode 13 and the lower transparent electrode 14 in the area inside from the position where the sealing material 15 is provided.
An upper protective film 16 and a lower protective film 17 made of iO ₂ or the like are provided. The upper and lower protective films 16 and 17 do not necessarily have to be provided.

On the upper electrode substrate 12, a display window 20 for displaying a display pattern is provided, and a frame plate 19 for covering a portion other than the display portion is provided. Further, a polymer dispersion type liquid crystal thin film 10 is provided thereon. Top transparent protective film 2 that contains a UV blocking material that prevents the liquid crystal material from being decomposed by UV light
Covered with 1. Further, under the lower electrode substrate 12, there is provided a reflector 22 provided at a position corresponding to the display pattern, determining a display color of the display pattern, and provided with a color reflective film which is fluorescent color printed to reflect light. It is provided. Further, the lower cover film 23 is provided below this, but it is not always necessary to provide this.

[0008]

As described above, the polymer-dispersed liquid crystal display device does not require a polarizing plate and an alignment film as compared with a liquid crystal display device using a conventional TN (twisted nematic) liquid crystal. Therefore, it has a characteristic that the structure is simple.

However, comparing the polymer dispersion type liquid crystal display device having the structure shown in FIG. 2 with the structure of the conventional TN liquid crystal display device, the upper transparent protective film 21, instead of the upper and lower polarizing plates, is provided. A lower cover film 23 is provided,
Instead of providing an alignment film, an upper protective film 16 and a lower protective film 17
Is provided, the number of constituent members is not reduced, and simplification of the structure is not realized.

An object of the present invention is to provide a polymer dispersion type liquid crystal display device capable of reducing the number of constituent members or simplifying the structure of the constituent members.

[0011]

In order to solve the above problems, the liquid crystal display device of the present invention comprises an upper electrode substrate provided with an upper transparent electrode and a lower electrode substrate provided with a lower transparent electrode. Overlap so that the surfaces with the transparent electrodes face each other, and
In a polymer dispersion type liquid crystal display device including a structure in which a polymer dispersion type liquid crystal thin film obtained by dispersing liquid crystal in a binder made of a polymer material is sandwiched between the both substrates, an ultraviolet ray cutting function, It is characterized in that the binder has at least one of an adhesion function and a water resistance function of the substrate, or at least one kind of member having at least one of the functions is mixed in the binder.

[0012]

In the liquid crystal display device of the present invention, the polymer dispersion type liquid crystal thin film is provided with the ultraviolet ray cutting function in the binder of the polymer dispersion type liquid crystal thin film, or by mixing the binder having the ultraviolet ray cut function in the binder. Since it is possible to add a UV blocking function, it is possible to omit the upper transparent protective film containing the conventional UV blocking material,
The structure and manufacturing process can be simplified.

Further, by providing the binder of the polymer-dispersed liquid crystal thin film with the adhesive function or the water resistant function of both substrates, or by mixing the members having the adhesive function of both substrate or the water resistant function in the binder, Since the adhesion function of both substrates or the water resistant function can be added to the molecular dispersion type liquid crystal thin film, the sealing by the sealing material can be omitted, and the structure and manufacturing process can be simplified.

[0014]

EXAMPLE FIG. 1 is an enlarged cross-sectional view of a main part of a polymer dispersion type liquid crystal display device according to an example of the present invention. 10 is a polymer dispersed liquid crystal thin film, 1 is a binder, 2 is a liquid crystal material, 3 is an ultraviolet blocking material, 4 is an adhesive material, 11 is an upper electrode substrate, 13 is an upper transparent electrode, 16 is an upper protective film, and 12 is a lower layer. An electrode substrate, 14 is a lower transparent electrode, and 17 is a lower protective film.

The polymer dispersed liquid crystal thin film 10 sandwiched between the upper transparent electrode 13 and the lower transparent electrode 14 provided on the upper electrode substrate 11 and the lower electrode substrate 12, respectively, is granular in a binder 1 made of a polymer material. Disperse the liquid crystal material 2 of
The liquid crystal material 2 is scattered in the inside. Binder 1
Is called a binder because the granular liquid crystal material 2 is fixed and the binder 1 and the liquid crystal material 2 are bonded to each other, and various methods and materials have already been announced. The granular liquid crystal material 2 is
It is also called a liquid crystal droplet, and may have a spherical shape or a flattened spherical shape, or may have an indefinite shape of a three-dimensional mesh. It is said that a spherical diameter of 1 to 2 μm is desirable in the case of a spherical shape. The liquid crystal material 2 is a member that gives electro-optical characteristics required for a liquid crystal display element. A dye may be introduced into the liquid crystal material 2 as needed to have light (color) absorption and transmission characteristics.

In the binder 1 of the polymer-dispersed liquid crystal thin film 10 having such a general structure, an appropriate amount of, for example, tunulin (trade name, manufactured by Ciba-Geigy Co., Ltd.) having an ultraviolet blocking function, an ultraviolet blocking material 3, for example, 1 of the total volume of binder 1
% Is mixed. As a result, an upper transparent protective film (reference numeral 2 in FIG. 2) containing an ultraviolet ray blocking material which has been conventionally required is included.
1) can be omitted, or it is possible to omit the inclusion of the ultraviolet blocking material in the upper transparent protective film, and the structure and manufacturing process can be simplified.

Further, for example, by mixing an appropriate amount of the low temperature adhesive material 4 of epoxy type having a curing temperature of about 100 ° C. in the binder 1, for example, 1% of the total volume of the binder 1,
Even without the sealing material (reference numeral 15 in FIG. 2), the upper and lower substrates 1
1, 12 and the polymer dispersed liquid crystal thin film 10 can be adhered to each other. Furthermore, in this embodiment, since the binder of silicon ladder type having excellent water resistance is used as the binder 1, the binder 1 has a water resistant function. With these,
The upper and lower substrates 11 and 12 which are conventionally required can be adhered, and the sealing material for preventing the intrusion of water into the polymer dispersed liquid crystal thin film 10 can be omitted, and the structure and the manufacturing process can be simplified. ..

The present invention has been specifically described above based on the embodiments, but the present invention is not limited to the above embodiments, and it is needless to say that various modifications can be made without departing from the scope of the invention. .. For example, in the above-mentioned embodiment, the polymer dispersed liquid crystal thin film 1 is provided to have the ultraviolet blocking function.
Although the ultraviolet blocking material 3 is mixed in the binder 1 of 0, the binder 1 may be formed of a material having an ultraviolet blocking function. Further, in the above embodiment, the adhesive 4 is mixed in the binder 1 of the polymer dispersed liquid crystal thin film 10 in order to have the adhesive function of both substrates, but the binder 1 is made of a material having an adhesive function such as epoxy. It may be formed. Further, in the above embodiment, the silicon ladder binder 1 having excellent water resistance is used to provide the water resistant function, but a member different from the binder having the water resistant function may be mixed in the binder 1.
Further, in the above embodiment, the above three functions are provided, but any one function or two functions may be provided.

[0019]

As described above, in the liquid crystal display device of the present invention, the binder of the polymer dispersed liquid crystal thin film is mixed with a member having an ultraviolet blocking function, an adhesive function of both substrates, and a water resistant function. Alternatively, by making the binder itself have these functions, the structure and manufacturing process of the liquid crystal display element can be simplified, and an economical liquid crystal display element can be provided.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a polymer-dispersed liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a partially exploded cross-sectional view of a conventional reflective polymer dispersed liquid crystal display device.

[Explanation of symbols]

1 ... Binder, 2 ... Liquid crystal material, 3 ... UV blocking material, 4 ...
Adhesive material, 10 ... Polymer dispersed liquid crystal thin film, 11 ... Upper electrode substrate, 12 ... Lower electrode substrate, 13 ... Upper transparent electrode, 14 ... Lower transparent electrode, 15 ... Sealing material, 16 ... Upper protective film, 17 ... Lower Protective film, 18 ... Conductive paste material, 19 ... Frame plate, 20 ... Display window, 21 ... Upper transparent protective film, 22 ... Reflector plate, 23 ...
Lower cover film.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Yanai 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Mobara factory

Claims (1)

[Claims] 1. An upper electrode substrate provided with an upper transparent electrode and a lower electrode substrate provided with a lower transparent electrode are laminated so that the surfaces provided with the respective transparent electrodes face each other and are made of a polymer material. In a polymer dispersion type liquid crystal display device comprising a structure in which a polymer dispersion type liquid crystal thin film obtained by dispersing liquid crystal in a binder is sandwiched between the both substrates, an ultraviolet ray cutting function, an adhesion function of the both substrates, A liquid crystal display device, wherein the binder has at least one of the water resistant functions, or at least one kind of member having at least one of the above functions is mixed in the binder.