JPH07104255A - Polymer dispersion type liquid crystal display element and its production - Google Patents

Abstract

PURPOSE:To produce a polymer dispersion type liquid crystal display element having a liquid crystal/polymer composite film between substrate in such a manner that no air bubble remains between the liquid crystal/polymer composite film and the inner surface of the substrate. CONSTITUTION:The one side transparent substrate 1 on which picture element electrodes 10 and active elements 11 are formed consists of a hard material such as glass. The other side transparent substrate 2 on which a counter electrode 12 is formed consists of a flexible resin film. The substrate 1 comprising the resin film is stuck to the other side transparent substrate 1 with a liquid crystal/polymer composite film 5 interposed. When the resin film substrate 2 is stuck to the substrate 1 comprising the hard material, the resin film substrate 2 is bent like an arc and the one side end of substrate 2 is brought into contact with the substrate 1 made of hard material. The the other end of the substrate 2 is stuck to the substrate 1 while pressing the substrate 2 to the substrate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer dispersion type liquid crystal display device for displaying an image by using a liquid crystal / polymer composite film in which a liquid crystal is dispersed in a polymer and a method for producing the same.

[0002]

2. Description of the Related Art A polymer-dispersed liquid crystal display device is a liquid crystal in which a liquid crystal is dispersed in a polymer in a cell in which a pair of transparent substrates having transparent electrodes are bonded via a frame-shaped sealing material.
A polymer composite film is provided, and as the liquid crystal, for example, nematic liquid crystal with positive dielectric anisotropy is used.

This polymer-dispersed liquid crystal display device is driven by applying a voltage between the electrodes of both substrates, and liquid crystal molecules dispersed in the polymer are not applied with a voltage. In the state, the light is oriented in various directions, and under this state, light passing through the liquid crystal / polymer composite film is scattered by the light scattering action of the liquid crystal. Then, when a voltage is applied between the electrodes, the molecules of the liquid crystal are uniformly oriented so as to stand substantially perpendicular to the substrate surface, and light is transmitted through the liquid crystal / polymer composite film with almost no scattering. Then, an image of a predetermined pattern is displayed by transmitting and scattering this light.

Such a polymer dispersion type liquid crystal display device is
A mixed liquid prepared by mixing a polymer material that undergoes a polymerization reaction with light or heat and liquid crystal is applied on one substrate, and then the other substrate is placed on one substrate with the coating film of the mixed liquid sandwiched therebetween. It is manufactured by a method in which a liquid crystal / polymer composite film is formed by bonding with a sealing material and then polymerizing the polymer material of the mixed solution by light or heat.

[0005]

However, in an active matrix type polymer dispersion type liquid crystal display device, a transparent substrate on which pixel electrodes and active devices are formed,
Both the transparent substrate on which the counter electrode is formed are made of a hard material such as glass, and therefore the mixed solution is applied on one substrate, and when the other substrate is bonded onto this substrate,
Air is trapped between the coating film of the mixed liquid and the inner surface of the other substrate to generate bubble-like air particles, which remain as they are on the inner surface of the substrate, and the air particles drive the liquid crystal display element. The electric field sometimes applied becomes non-uniform, resulting in display unevenness.

The present invention has been made by paying attention to such a point, and an object thereof is to provide a polymer dispersion type liquid crystal display element capable of preventing the occurrence of display unevenness due to air particles. It is to provide the manufacturing method.

[0007]

In order to achieve such an object, the present invention has a flexible resin film in which a pixel electrode and an active element are formed on a substrate made of a hard material such as glass. A counter electrode is formed on a substrate made of, further, a mixed solution of a polymer material and liquid crystal is applied on one of the substrates, and a sealing material is applied on the other transparent substrate. , The substrate made of a resin film is curved in an arc shape with the surface on which the counter electrode is formed facing downward,
While contacting one end side of the surface on the substrate made of a hard material, the substrate made of a resin film is pressed against the substrate made of a hard material toward the other end side in order to make the substrate made of a resin film from the hard material. The substrate is bonded to the substrate via the sealing material, and then the polymer material of the mixed solution is polymerized to form a liquid crystal / polymer composite film.

[0008]

[Function] A substrate made of a resin film is curved in an arc shape, one end side of the surface is brought into contact with a substrate made of a hard material, and the other end side of the substrate made of the resin film is sequentially made a substrate made of a hard material. When sticking while pressing, the air between the coating film of the mixed liquid applied on one substrate and the inner surface of the other substrate is extruded in sequence, and therefore, the air between the mixed liquid coating film and the inner surface of the substrate is pushed out. Air is rarely trapped in the inner surface of the substrate, and the inner surface of the substrate adheres to the entire coating film of the mixed liquid, and the generation of air particles is suppressed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of a polymer dispersed liquid crystal display device. This polymer-dispersed liquid crystal display device has a structure in which a pair of transparent substrates 1 and 2 are bonded together via a frame-shaped sealing material 3 and a liquid crystal / polymer composite film 5 is provided between the substrates 1 and 2. Has become. The liquid crystal / polymer composite film 5 has a structure in which a liquid crystal 7 is dispersed in a transparent polymer 6, as shown in FIG.

The one substrate 1 is made of a hard material such as glass, and a plurality of transparent pixel electrodes 10 arranged on the substrate 1 in the row direction and the column direction and corresponding to the pixel electrodes 10 respectively. A plurality of active elements 11 are formed.

The active element 11 is, for example, a TFT (thin film transistor). Although not shown, the TFT is a gate electrode formed on the substrate 1, a gate insulating film covering the gate electrode, and the gate insulating film. It is composed of a semiconductor film made of a-Si (amorphous silicon) or the like which is formed on the upper surface so as to face the gate electrode, and a source electrode and a drain electrode which are formed on both sides of the semiconductor film.

Further, although not shown, on the substrate 1,
A gate line (address line) for supplying a gate signal to the TFT and a data line for supplying a data signal according to image data to the TFT are wired.
The gate electrode of the FT is formed integrally with the gate line, and the drain electrode is connected to the data line.

The other substrate 2 is made of a flexible resin film, and a transparent counter electrode 12 is formed on the inner surface of the substrate 2 so as to face all the pixel electrodes 10 formed on the one substrate 1. Are formed.

FIG. 3 schematically shows a process for manufacturing the polymer dispersion type liquid crystal display device. Next, the manufacturing process will be described. In addition, in FIG. 3, the pixel electrode 10 and the active element 11 formed on the substrate 1,
Further, the counter electrode 12 formed on the substrate 2 is omitted.

First, as shown in FIG. 3A, on one substrate 1 on which pixel electrodes and active elements are formed, for example, light (wavelength of ultraviolet ray) is provided so as to cover each pixel electrode and each active element. A mixed liquid 5'of a photo-curable polymer material which is polymerized and hardened by a region) and liquid crystal is uniformly applied by screen printing or gravure printing.

The other substrate 2 on which the counter electrode is formed
Then, the sealing material 3 is applied in a frame shape by screen printing or a dispenser to a portion of a region slightly wider than the contour of the application region of the mixed liquid 5 '. As the material of the sealing material 3, for example, a photo-curable polymer material that is polymerized and cured by light (wavelength range of ultraviolet rays) is used.

Next, as shown in FIG. 3B, the coating film of the mixed solution 5 ′ is arranged inside the sealing material 3,
The other substrate 2 is superposed on the one substrate 1. At this time, as shown in FIG. 4, the other substrate 2 made of a resin film is curved in an arc shape, and the inner surface on one end side of this substrate 2 is brought into contact with the upper surface on the one end side of one substrate 1, and, for example, a roller is used. The substrate 2 is attached to the substrate 1 while sequentially pressing the substrate 2 to the other end side of the substrate 1 using 13.

In this way, the substrate 2 is curved in an arc shape,
When the inner surface is pressed against the substrate 1 in order from the one end side to the other end side, the mixed solution 5'applied on the substrate 1
Between the coating film of the mixed liquid 5'and the inner surface of the substrate 2 is extruded in sequence, so that the air is hardly trapped between the coating film of the mixed liquid 5'and the inner surface of the substrate 2. The inner surface of the is adhered to the entire coating film of the mixed liquid 5 ', and the generation of air particles is suppressed.

Substrate 2 made of resin film on substrate 1
After the bonding is performed, as shown in FIG. 3C, the ultraviolet light is evenly irradiated from the outer surface side of the substrate 2 toward the both substrates 1 and 2 by the ultraviolet lamp 14. By this irradiation, the polymer material in the mixed liquid 5'is polymerized by the ultraviolet light and the liquid crystal is phase-separated, and the mixed liquid 5'becomes the liquid crystal / polymer composite film 5. At this time, the sealing material 3 is also cured by the ultraviolet light, and the two substrates 1 and 2 are integrally bonded.

In the above embodiment, the pixel electrode 1
0 and the hard substrate 1 on which the active elements 11 are formed are coated with the mixed solution 5 ', but the mixed solution 5'is formed on the substrate 2 made of a resin film on which the counter electrode 12 is formed.
Then, the substrate 2 is coated on the substrate 1 with the coating film of the mixed solution 5'downward on one substrate 1 from the one end side to the other end side in the same manner as in the above embodiment. You may make it bond together pressing, and also in such a case, the air between the coating film of the mixed liquid 5'coated on the substrate 2 and the inner surface of the substrate 1 is sequentially pushed out, and the mixed liquid 5'is Air is not trapped between the coating film and the inner surface of the substrate 1, and the generation of air particles can be suppressed.

In the above embodiment, a photo-curable resin is used as the polymer material of the composite film, but a thermosetting resin is used, and the liquid crystal / polymer composite film is formed by thermal polymerization reaction. This may be the case. Further, as an active element formed on a substrate made of a hard material, TF
Not limited to T, it may be MIM or the like.

[0022]

As described above, according to the present invention, when a substrate made of a resin film is attached to a substrate made of a hard material, air is extruded between the coating film of the mixed liquid and the inner surface of the substrate. Therefore, air particles do not remain between the liquid crystal / polymer composite film formed by the mixed liquid and the inner surface of the substrate, and therefore display unevenness caused by air particles is prevented from occurring and the display quality is improved. You can

[Brief description of drawings]

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

FIG. 2 shows the liquid crystal / liquid crystal in the polymer dispersed liquid crystal display device.
Sectional drawing which expands and shows a part of polymer composite film.

FIG. 3 is a process explanatory view schematically showing a process for manufacturing the polymer dispersed liquid crystal display element.

FIG. 4 is a cross-sectional view showing a state in which one substrate is attached to the other substrate during the process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hard material substrate 2 ... Resin film substrate 3 ... Sealing material 5 ... Liquid crystal / polymer composite film 5 '... Mixed liquid of polymer material and liquid crystal 10 ... Pixel electrode 11 ... Active element 12 ... Counter electrode

Claims (2)

[Claims] 1. A transparent substrate on which a counter electrode is formed is attached to a transparent substrate on which a pixel electrode and an active element are formed via a frame-shaped sealing material, and a liquid crystal in a polymer between the both substrates. In a polymer-dispersed liquid crystal display element provided with a liquid crystal / polymer composite film in which is dispersed, the one transparent substrate on which the pixel electrode and the active element are formed is made of a hard material such as glass, and the counter electrode is formed. In addition, the other transparent substrate is made of a flexible resin film, and the substrate made of the resin film is bonded to the one transparent substrate with a liquid crystal / polymer composite film interposed therebetween. Dispersed liquid crystal display device. 2. A transparent substrate on which a counter electrode is formed is attached to a transparent substrate on which a pixel electrode and an active element are formed via a frame-shaped sealing material, and a liquid crystal in a polymer is placed between the two substrates. A method of manufacturing a polymer dispersion type liquid crystal display element provided with a liquid crystal / polymer composite film in which a pixel electrode and an active element are formed on a substrate made of a hard material such as glass, and the flexible film is formed. A counter electrode is formed on a substrate made of a resin film having high properties, and then a mixed liquid of a polymer material and liquid crystal is applied on one of the substrates, and the other substrate is sealed. Material is applied, the substrate made of a resin film, curved in an arc shape with the surface on which the counter electrode is formed facing downward, and one end side of the surface is brought into contact with the substrate made of a hard material, A substrate made of the resin film The substrate made of a resin film is sequentially pressed against the substrate made of a hard material toward the other end side and bonded to the substrate made of a hard material via the sealing material,
Thereafter, the polymer material of the mixed solution is polymerized to form a liquid crystal / polymer composite film, which is a method for producing a polymer dispersed liquid crystal display device.