JPH04289821A - Liquid crystal display material and liquid crystal display element using this material - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display material with no polarizer required and a liquid crystal display element of using this material with no back light required. CONSTITUTION:Since a liquid crystal 4a, dispersed in amorphous oxide(silicon oxide, aluminum oxide, titanium oxide, etc.) 4b, having three-dimensional mesh structure, is arranged at random along a mesh interface in a condition of applying no voltage, incident light is scattered and placed in a cloudy condition. When voltage is applied, a molecular major axis of the liquid crystal 4a is arranged in an electric field direction, so that light is permeated transparent. When a display element is constituted by using this material, no polarizer is required, so that a bright clear picture plane is obtained even without back light.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to liquid crystal display materials and liquid crystal display elements.

0002

[Prior Art] Figure 4 shows a T
This is a basic schematic cross-sectional view of an N (twisted nematic) type liquid crystal display element, showing a liquid crystal layer 14 with a thickness of approximately 10 μm.
is sandwiched between two glass substrates 11a and 11b each having transparent electrodes 12a and 12b and alignment films 18a and 18b, and the outer periphery of the liquid crystal layer 14 is hermetically sealed with a sealing material 13, resulting in a panel-like cell structure. doing. The liquid crystal layer 14 consists of liquid crystal and spacers for making the cell gap uniform. Then, sheet-like polarizers 17a and 17b were attached to both sides of this cell, and in the case of a reflective type, a sheet-like reflective plate 15 was provided on one side of one polarizer 17b. The reflective plate 15 is not provided in the transmission type.

In this TN type liquid crystal display element, when no voltage is applied between the transparent electrodes 12a and 12b of the cell, the alignment films 18a and 18b cause the liquid crystal in the liquid crystal layer 14 to have its molecular long axis aligned with 2. The glass substrates 11a to 11b are oriented in a continuous 90 degree twisted state. Then, the incident light becomes linearly polarized by the polarizer 17a or 17b and enters the cell. The polarization direction of linearly polarized light that is perpendicularly incident on the cell is rotated by 90 degrees along the twist of the liquid crystal molecules while passing through the cell. Therefore, this cell transmits light between orthogonal polarizers (when polarizers 17a and 17b are arranged orthogonally) and between parallel polarizers (when polarizers 17a and 17b are arranged orthogonally).
b are arranged in parallel), the light is blocked.

Next, transparent electrodes 12a and 12b are attached to this cell.
When more voltage is applied, the long axis of the liquid crystal molecules begins to tilt toward the electric field direction from a certain threshold voltage. Then, with an applied voltage of about twice the threshold voltage, the long axes of all liquid crystal molecules other than those in the vicinity of the electrodes are rearranged parallel to the direction of the electric field, and the 90 degree optical rotation disappears. In this state, completely opposite to the case where no voltage is applied, light is blocked between the orthogonal polarizers, and light is transmitted between the parallel polarizers. Display was performed based on this operating principle.

[0005]

However, in the liquid crystal display element having the above structure, the screen becomes dark because a polarizer is used. The reason is that the light transmittance of a polarizer is generally 30 to 50%, and when two polarizers are used, the polarizer absorbs 3/4 or more of the incident light.

[0006] For this reason, in large-screen display devices, a backlight was attached to the back of the panel to ensure brightness, but when a backlight was attached, power consumption increased and the temperature of the cell increased due to the heat of the backlight. There was a problem that display quality deteriorated. Further, there is a problem that a thin display device cannot be realized. The present invention solves the above-mentioned conventional problems and provides a liquid crystal display material whose operating principle is a scattering mode that does not require a polarizer, and a liquid crystal display element using the material that can display a bright and clear screen even without a backlight. The purpose is to provide.

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present invention uses a composite of an amorphous oxide having a three-dimensional network structure and a liquid crystal as a liquid crystal display material. Furthermore, in order to solve the above-mentioned problems, the present invention includes a display layer made of a composite of an amorphous oxide and a liquid crystal having a three-dimensional network structure, and a display layer each having a transparent electrode, sandwiching the display layer. 1. A liquid crystal display element characterized by comprising a second transparent insulating substrate was constructed.

[0008]

[Function] According to the present invention, since the liquid crystal display material is constructed as described above, when no voltage is applied to the liquid crystal display material, the liquid crystal dispersed in the amorphous oxide will move along the mesh interface. Since they are arranged randomly, the incident light is scattered and becomes cloudy. On the other hand, when voltage is applied to the liquid crystal display material,
The long axes of liquid crystal molecules are aligned in the direction of the electric field, allowing light to pass through it and making it appear transparent. Therefore, a cloudy or transparent display can be achieved.

Further, according to the present invention, since the liquid crystal display element is constructed as described above, the cloudy or transparent state of the display layer can be changed by the voltage applied to the transparent electrodes provided on the first and second transparent insulating substrates. can be controlled.

0010

EXAMPLES Before describing examples of the present invention, first, a method for producing a liquid crystal display material according to the present invention will be explained. A composite of an amorphous oxide and a liquid crystal having a three-dimensional network structure is synthesized by applying, for example, a sol-gel method.

[0011] In general, the sol-gel method is a method for synthesizing solid glasses and ceramics from liquid raw materials of various chemical compositions through the sol state and gel state. A sol is a colloid that uses a liquid as a dispersion medium, that is, a substance is dispersed as particles that are larger than atoms or small molecules but cannot be seen with a normal microscope. A gel is a jelly-like solidification of a sol. It is.

[0012] In this method, metal alkoxide is generally dissolved in a solvent, and water and additives are added to hydrolyze it. As the chemical reaction progresses, an amorphous oxide having a three-dimensional network structure is formed. Solization, gelation, and solidification progress, and finally, glass and ceramics are obtained by heat treatment at high temperatures. However, if heat treatment is performed at a low temperature, a porous amorphous oxide with a three-dimensional network structure can be obtained.

In the present invention, silicon oxide, aluminum oxide, titanium oxide, etc. were used as the amorphous oxide, and nematic liquid crystal used in TN cells was used as the liquid crystal. That is, silicon, aluminum, titanium, etc. and nematic liquid crystal are dissolved in a solvent such as ethanol or isopropyl alcohol, and hydrolyzed using an additive such as hydrochloric acid or sodium hydroxide at a temperature that does not decompose the liquid crystal (approximately 50 to 50℃). A composite of an amorphous oxide with a three-dimensional network structure and liquid crystals dispersed in the network was obtained by heat treatment at 150°C.

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram of the operating principle of a liquid crystal display material according to an embodiment of the present invention. As shown in FIG. 1(a), when no voltage is applied, the liquid crystal 4a dispersed in the amorphous oxide 4b having a three-dimensional network structure is randomly arranged along the network interface, so that the incident light is scattered and becomes cloudy. On the other hand, when a voltage is applied to the display layer as shown in FIG. 1(b), the molecular long axes of the liquid crystal 4a are aligned in the direction of the electric field, allowing light to pass through and appear transparent. Therefore, a cloudy or transparent display can be achieved.

Note that the liquid crystal 4 mixed with the amorphous oxide 4b
The amount of a is 1 to 10 parts by weight of the liquid crystal per 1 part by weight of the amorphous oxide.
Parts by weight are preferred. If the amount of liquid crystal is less than this amount, scattering by the liquid crystal will be reduced and a sufficient cloudy state will not be obtained. Also,
If the amount of liquid crystal is greater than this amount, the network density of the amorphous oxide will decrease, and the degree of random orientation of the liquid crystal will decrease, making it impossible to obtain a sufficient cloudy state.

Next, a liquid crystal display element according to an embodiment of the present invention will be explained. (First Embodiment) FIG. 2 is a schematic cross-sectional view of a liquid crystal display element showing a first embodiment of the present invention. layer 4,
two substrates 1a each provided with transparent electrodes 2a and 2b;
1b, and the outer periphery of the display layer 4 was hermetically sealed with the sealing material 3 to form a panel-shaped liquid crystal display element.

[0017] The substrates 1a and 1b are made of glass or plastic film, and the surfaces are coated with In2O3-SnO2.
A transparent electrode of metal such as (ITO) or SnO2 is formed. The transparent electrodes 2a and 2b are patterned in various ways depending on the driving method, display content, and purpose (consisting of segment electrodes, fixed pattern electrodes, matrix electrodes, etc.), and the display layer 4
Apply a predetermined voltage to. The sealing material 3 was used to bond the substrates 1a and 1b stacked at a constant distance and to hermetically seal the liquid crystal, and was made of epoxy resin, acrylic resin, silicone resin, or the like. The reflector plate 5 is used for a reflective type display, and is not necessary for a transmissive type display. (Second Embodiment) FIG. 3 is a schematic cross-sectional view of a liquid crystal display element showing a second embodiment of the present invention, in which the transparent electrode 2b is composed of a matrix electrode, and a switch element is connected to each pixel at the matrix intersection. A TFT (thin film transistor) 6 and a capacitor element are added and integrated as needed.

The TFT 6 provided for each pixel prevents crosstalk by independently separating the transparent electrode 2b, which is each pixel electrode, and the capacitor element plays the role of accumulating signal charges for one frame time. Note that the present invention is not limited to the above-described embodiments, and various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0019]

[Effects of the Invention] As explained in detail above, according to the present invention, since the layer made of a composite of an amorphous oxide and liquid crystal having a three-dimensional network structure is used as a display layer, the following effects can be achieved. play. (1) A display element with a bright and clear screen can be realized without a backlight.

(2) Since no backlight is required, power consumption is low and a thin or large liquid crystal display device can be constructed. (3) Since a polarizer and an alignment film are not required, a liquid crystal display device with a simple structure, easy to manufacture, and low manufacturing cost can be realized.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the operating principle of a liquid crystal display material according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a liquid crystal display element according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a liquid crystal display element according to another embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a conventional liquid crystal display element.

[Explanation of symbols]

1a, 1b Glass substrates 2a, 2b Transparent electrode 3 Sealing material 4 Display layer 4a Liquid crystal 4b Amorphous oxide 5
a reflector

Claims (5)

[Claims] 1. A liquid crystal display material comprising a composite of an amorphous oxide and liquid crystal having a three-dimensional network structure. 2. The liquid crystal display material according to claim 1, wherein silicon oxide, titanium oxide, or aluminum oxide is used as the amorphous oxide. [Claim 3] 1 part by weight of liquid crystal per 1 part by weight of amorphous oxide.
The liquid crystal display material according to claim 1 or 2, wherein the liquid crystal display material is mixed with 10 parts by weight. 4. (a) a display layer made of a composite of an amorphous oxide and a liquid crystal having a three-dimensional network structure, and (b) first and second layers each having a transparent electrode and sandwiching the display layer. 2. A liquid crystal display element comprising: 2 transparent insulating substrates. 5. The liquid crystal display element according to claim 2, wherein the first or second transparent insulating substrate has a thin film transistor.