JPH0695053A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display device which is thin and light in weight by using just one sheet of substrate having a thickness. CONSTITUTION:Mixtures composed of high-polymer resins and liquid crystal materials are irradiated with light by using mask patterns. As a result, the plural mixture parts along the surface of a glass substrate 1 are cured. The cured part are formed at the points exclusive of picture elements which do not contribute to display. In succession, the front surfaces on the side opposite from the substrate are subjected to photoirradiation for, for example, a short period of time. As a result, a thin film is formed over the entire surface of the mixture surface on the side opposite from the substrate 1. In succession, a counter electrode 9 and a surface protective film 10 are formed on the cured thin film. Color filters 4 are formed on the substrate 1 side. The ruggedness on the surface by the formation of these color filters 4 is eventually eliminated by a flattening film 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin and compact reflective and transmissive liquid crystal display device.

[0002]

2. Description of the Related Art As the liquid crystal display device, a color display device having a thin film transistor (TFT) is known. FIG. 5 shows a typical structure of a liquid crystal display device for color display including the above-mentioned TFT. This liquid crystal display device has a structure in which a liquid crystal layer 23 is sandwiched between two glass substrates 21 and 22, and a gate bus line and a source bus are provided on one (lower side in the illustrated example) glass substrate 21. The lines are formed so as to be orthogonal to each other, and the TFT 25a and the pixel electrode 26 made of a light transmissive material are formed in the vicinity of the intersection. A color filter 24 and a transparent counter electrode 27 are formed on the other glass substrate 22.
An alignment film is formed on the inner surfaces of the substrates 21 and 22 in contact with the liquid crystal layer 23.

When the liquid crystal display device having such a structure is irradiated with white light from the back surface side, color display is performed by utilizing the electrical switching characteristics of the TFT 25a. The display mode used is TN mode.

The above-described method of manufacturing a liquid crystal display device is conventionally performed as shown in FIG. That is, first,
TFTs are formed on one glass substrate (step 1), and color filters are formed on the other glass substrate (step 2). Then, the glass substrate on which the TFT is formed and the glass substrate on which the color filter is formed are bonded (step 3), and liquid crystal is injected between both substrates (step 4). As a result, the liquid crystal display device body is manufactured.
Further, a driver for driving is mounted on the main body of the liquid crystal display device (step 5).

[0005]

By the way, in recent years, as the advanced information society has advanced, the information armament of individuals has become remarkable. In addition, miniaturization of information devices has become possible due to technological progress such as flattening of displays and high integration of LSIs. Against this background of society, the trend toward an era in which information devices are becoming portable and personalization is difficult to move. In that case, when the conventional technique is used to reduce the thickness, the glass substrate is
Since one sheet is required, a maximum thickness of 2 mm is required, and when the weight is to be reduced, there is a limitation such that two glass substrates are heavier. Therefore, it is difficult to achieve compactness.

The present invention has been made to solve the problems of the prior art, and an object thereof is to provide a method for manufacturing a thin and lightweight liquid crystal display device.

[0007]

According to a method of manufacturing a liquid crystal display device of the present invention, an active matrix substrate having a pixel electrode is disposed on one side of a liquid crystal layer and a counter electrode and a surface protection are provided on the other side. A method of manufacturing a liquid crystal display device in which a film is provided and pixels are provided in a matrix form, the step of providing a mixture of a photocurable polymer resin and a liquid crystal material on the active matrix substrate. And irradiating the mixture with light using a mask pattern to cure the mixture portion other than the picture element, and removing the mask pattern to cover the entire surface of the mixture opposite to the substrate. Since the method includes the steps of irradiating light and forming a thin film formed by curing on the upper layer portion of the surface, and the step of forming a counter electrode and a surface protective film on the thin film, thereby achieving the above object. To be done.

As the liquid crystal material, a material to which a dichroic dye is added can be used.

As an active matrix substrate,
The scanning line and the signal line are formed to intersect with each other, an active element is formed in the vicinity of the intersection of both lines, a color filter is further formed on the active element, and then a flattening film is formed to flatten the flattening film. You may use what was produced by connecting a pixel electrode and an active element through the film.

Further, either one of the picture element electrode and the counter electrode may be formed of a metal thin film.

[0011]

In the present invention, a mixture of a polymer resin and a liquid crystal material is irradiated with light using a mask pattern. This cures the portions of the mixture along the surface of the substrate. This hardened part is a part other than the picture element that does not contribute to the display. Then, the surface of the mixture in this state on the side opposite to the substrate is irradiated with light for a short time, for example. As a result, a thin film is formed on the entire surface of the mixture opposite to the substrate. Then, a counter electrode and a surface protective film are formed on the cured thin film.

The color filter is formed on the active matrix substrate side. The unevenness on the surface due to the formation of the color filter is eliminated by the flattening film.

[0013]

EXAMPLES Examples of the present invention will be specifically described below.

FIG. 1 is manufactured by applying the method of the present invention,
The direct-view type liquid crystal display device when an active element is TFT is shown. In this liquid crystal display device, a gate bus line and a source bus line (not shown) are wired on a glass substrate 1 in a state where they intersect with each other, and a plurality of TFTs 5b in which a driver is monolithically formed of polysilicon are formed near the intersections. . That is, the active matrix substrate is formed. Instead of the glass substrate 1, a transparent insulating substrate made of another material can be used.

Glass substrate 1 on which the TFT 5b is formed
A color filter 4 is formed on the glass substrate 1, and a flattening film 6 made of acrylic resin is formed on the glass substrate 1 on which the color filter 4 is formed. Further, a pixel electrode 7 is formed on the flattening film 6. Has been formed. This pixel electrode 7 is T
It is connected to the drain of FT5b. This pixel electrode 7
A polymer-dispersed liquid crystal layer 8 carrying a liquid crystal is formed almost all over the glass substrate 1 on which the counter electrode 9 and the surface protective film 10 are formed on the polymer-dispersed liquid crystal layer 8. And are formed in this order.

A method of manufacturing the liquid crystal display device having such a structure will be described below.

First, as shown in FIG. 2, a plurality of TFTs 5b each having a monolithic driver made of polysilicon are formed on the glass substrate 1.

Next, on the glass substrate 1 on which the TFT 5b is formed, a complementary or primary color filter 4 is provided, for example, a pigment dispersion type photosensitive resin COLOR manufactured by Fuji Hunt.
It is formed using MOSAIC.

Next, for example, OPMER SS, which is an acrylic resin made of Japan Synthetic Rubber, is applied and baked to form the flattening film 6. In this case, the photosensitive resin COLOR MOSAIC on the drain of the TFT 5b is removed by photoetching, and the optomer SS is patterned by Shipley's photoresist AZ1450J so as to expose only the vicinity of the drain, and then removed by dry etching. Is a stripper O made by Tokyo Ohka
Peel off with MR stripper. The presence of the flattening film 6 makes it possible to eliminate surface irregularities regardless of the formation of the color filter 4.

Next, a pixel electrode 7 made of ITO (indium tin oxide) is formed by sputtering. At this time, the pixel electrode 7 is connected to the drain of the TFT 5b.

Next, an ultraviolet curable resin and a nematic or smectic liquid crystal to which an anthraquinone dye, which is a dichroic dye, is mixed thereon to form a uniform liquid polymer dispersion type liquid crystal precursor. The mixture is applied by a roll coater or a spin coater to a thickness of 5 to 20 μm.

Next, using the mask pattern, the mixture is irradiated with ultraviolet rays to cure the portion of the mixture other than the final pixel. At this time, ultraviolet rays are irradiated at a predetermined temperature. As a result, the polymer-dispersed liquid crystal layer 8 in which the liquid crystal is supported by the polymer network made of the ultraviolet curable resin is formed.

Next, the mask pattern is removed, and the entire surface of the mixture opposite to the substrate is irradiated with ultraviolet rays to form a flat thin film on the upper layer of the corresponding surface by curing.

Next, a counter electrode 9 is formed by sputtering or vapor deposition using a metal such as ITO or aluminum.

Next, an acrylic resin or a urethane resin is applied on the counter electrode 9 and then baked to form a surface protective film 10. It is preferable that the surface protective film 10 has a surface with increased hardness and is flattened.

In the liquid crystal display device manufactured as described above, when a voltage is applied, the refractive index of the polymer layer and the liquid crystal are matched, light scattering disappears and the liquid crystal becomes transparent, so that color display is possible. Becomes On the other hand, when no voltage is applied, black is displayed due to the presence of the dichroic dye described above due to scattering due to mismatching. In addition, the counter electrode 9
When it is formed of a metal having a high reflectance such as aluminum, it can be used as a reflection plate, and when the glass substrate 1 side is used as a display side, it can be used as a reflection type liquid crystal display device.

In this example, when the polymer dispersed liquid crystal layer has a polymer network structure but the liquid crystal is not completely retained in the polymer carrier, the following is preferable. That is, in the surface protective film 10,
A heat-resistant transparent film with small optical anisotropy such as polystyrene or polyethylene terephthalate is used, and a counter electrode made of a metal such as ITO or aluminum is formed on the film to cover the liquid crystal layer, and then an ultraviolet curable resin, etc. May be used to seal the periphery of the liquid crystal layer. In this case, in the present invention, since the counter electrode 9 and the surface protective film 10 are formed after forming the cured thin film on the upper surface of the polymer dispersed liquid crystal layer 8, the surface protective film 10 is formed.
Even if a film is used, it is easy to stick, and when a film having the counter electrode 9 formed thereon is stuck, the risk of disconnection of the counter electrode 9 is extremely small.

In the above embodiment, the color filter 4 is formed on the glass substrate 1 side, but the present invention is not limited to this, and the color filter 4 is formed on the surface protective film 10 side as shown in FIG. Good.

Although the color filter 4 is formed in the above embodiment, the present invention is not limited to this, and the color filter 4 may not be formed. When the color filter 4 is not formed, the pixel electrode 7 may be made of metal and the counter electrode 9 may be transparent.

Although the liquid crystal display device is manufactured by using the mixture in which the dichroic dye is contained in the liquid crystal material in the above embodiment, the present invention is not limited to this, and the dichroic dye is contained in the liquid crystal material. A liquid crystal display device may be manufactured using a mixture containing no. In the liquid crystal display device manufactured in this manner, as shown in FIGS. 4A and 4B, if a Schlieren optical system is used, a polarizing plate becomes unnecessary, and a compact single-substrate bright single-plate color projector is provided. realizable. That is, when the voltage is off, unnecessary scattered light does not pass through the light diaphragm, and when the voltage is off, bright color parallel rays can be displayed on the screen by the diaphragm.

[0031]

As described above, according to the present invention,
Since only one thick substrate is used, it is very thin. Therefore, the thickness of the liquid crystal display device is about half that of the conventional one. Therefore, a glass substrate with a color filter, a driver IC, etc. are not necessary, and the cost can be greatly reduced. Further, the liquid crystal display device of the present invention can be used not only as a direct-view type transmission type and reflection type but also as a projection type.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a liquid crystal display device of this embodiment.

FIG. 2 is an explanatory diagram of a process of mounting a driver on the glass substrate of FIG.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a configuration in which a liquid crystal display device manufactured according to the present invention is applied to a Schlieren optical system.

FIG. 5 is a cross-sectional view showing a conventional liquid crystal display device.

FIG. 6 is a process chart showing a method of manufacturing a conventional liquid crystal display device.

[Explanation of symbols]

 1 Glass Substrate 4 Color Filter 5b TFT 6 Flattening Film 7 Picture Element Electrode 8 Polymer Dispersed Liquid Crystal Layer 9 Counter Electrode 10 Surface Protective Film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Toda 22-22 Nagaike-cho, Abeno-ku, Osaka City, Osaka Prefecture

Claims (4)

[Claims] 1. An active matrix substrate having a picture element electrode is disposed on one side of a liquid crystal layer, and a counter electrode and a surface protective film are provided on the other side, and the picture elements are provided in a matrix. And a step of providing a mixture of a photocurable polymer resin and a liquid crystal material on the active matrix substrate, and irradiating the mixture with light using a mask pattern. Curing the mixture portion other than the picture element, removing the mask pattern, irradiating the entire surface of the mixture opposite to the substrate with light, and curing the upper layer portion of the surface. A method of manufacturing a liquid crystal display device, comprising: a step of forming a thin film; and a step of forming a counter electrode and a surface protective film on the thin film. 2. The method for manufacturing a liquid crystal display device according to claim 1, wherein a liquid crystal material to which a dichroic dye is added is used. 3. The active matrix substrate,
The scanning line and the signal line are formed to intersect with each other, an active element is formed in the vicinity of the intersection of both lines, a color filter is further formed on the active element, and then a flattening film is formed to flatten the flattening film. The method for manufacturing a liquid crystal display device according to claim 1, wherein a liquid crystal display device manufactured by connecting a pixel electrode and an active element through a film is used. 4. The method of manufacturing a liquid crystal display device according to claim 1, wherein one of the pixel electrode and the counter electrode is formed of a metal thin film.