JP2769398B2 - Manufacturing method of scattering type liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a scattering type liquid crystal display device .
It relates to a manufacturing method .

[0002]

2. Description of the Related Art There are various types of liquid crystal display devices depending on differences in optical properties such as phase transition and fluidity of liquid crystal and molecular alignment control methods by electric fields and the like. One of them is a scattering type liquid crystal display device, which is widely used.
Such a scattering type liquid crystal display device will be described with reference to FIG.

The manufacture of a liquid crystal panel 100 as a scattering type liquid crystal display device shown in a partial sectional view in FIG. 10 (a) is performed as follows. That is, first, a pair of substrates 101 each having electrodes formed on an insulating substrate are adhered to each other with an appropriate gap therebetween, and the gap is filled with a mixture of a UV-polymerizable high molecular compound precursor and a liquid crystal material and sealed. I do. Next, when ultraviolet rays are irradiated, the polymer compound precursor is polymerized, and phase separation occurs. At this time, the liquid crystal molecules 103 constituting the liquid crystal phase 102 are dispersed in the network structure of the polymer compound 104 and are oriented along the interface 105 with the polymer compound as a carrier.

When an image is displayed on the liquid crystal panel 100 manufactured as described above, the orientation direction of the liquid crystal molecules in the liquid crystal panel 100 is random when no voltage is applied as shown in FIG. Thus, light incident on the liquid crystal panel 100 is scattered. Next, when a voltage is applied to the polymer-dispersed liquid crystal layer, the liquid crystal molecules are oriented in the direction of electrolysis as shown in FIG.

As described above, in the conventional scattering type liquid crystal display device, an image is displayed by controlling the scattering state and the transparent state by the applied voltage.

[0006]

It is generally desired that a liquid crystal display device can be manufactured more easily while at the same time obtaining higher display characteristics and higher reliability.

However, the electro-optical characteristics of the above-mentioned conventional polymer-dispersed liquid crystal largely depend on the network structure of the polymer compound. That is, the scattering characteristics change depending on the average value and distribution of the size of the liquid crystal layer dispersed in the network structure. Therefore, in order to obtain appropriate electro-optical characteristics, delicate control of the polymer network structure must be performed, and adjustment of the polymer and liquid crystal materials, or optimization of the irradiation amount and irradiation time of ultraviolet rays to be irradiated, etc. It causes serious difficulties.

In addition, when the polymer compound precursor is polymerized by irradiation with ultraviolet rays, unreacted substances and by-products remain, which has a problem that display characteristics and reliability of the liquid crystal panel are adversely affected.

The present invention has been made in view of the above-described conventional problems, and can display a high-quality image.
An object of the present invention is to provide a method of manufacturing a highly reliable scattering type liquid crystal display device.

[0010]

According to the present invention, there is provided a method for manufacturing a scattering type liquid crystal display device , comprising the steps of:
Forming a pixel electrode, forming an insulating layer on the pixel electrode,
Forming a plurality of holes in the insulating layer;
Fills liquid crystal containing compound and forms counter electrode on second substrate
And bonding the first substrate and the second substrate together.
A method for manufacturing a scattering type liquid crystal display device, comprising:
The substrate was placed in a vacuum environment and the plurality of holes were formed.
The liquid crystal is dropped on an insulating layer, and the first substrate is disposed.
The ambient environment is returned to normal pressure, and the first substrate is
The extra liquid crystal by installing it and rotating it.
Filling the plurality of holes with the liquid crystal by removing
It is characterized by that .

[0011]

According to the method of manufacturing a scattering type liquid crystal display device of the present invention,
When a voltage is applied between the pixel electrode and the counter electrode in the manufactured liquid crystal display device, an electric field is generated in the insulating layer, and the liquid crystal containing the chiral compound filled in a plurality of holes provided in the insulating layer. Are oriented in the direction of the electric field and become transparent. If no electric field is applied, the orientation direction becomes random, and the liquid crystal scatters incident light. Therefore, if the scattering state and the transparent state of the liquid crystal are controlled by the voltage applied between the pixel electrode and the counter electrode, display can be performed by the pixel corresponding to the pixel electrode by using the scattering action of the liquid crystal. Here, the liquid crystal is provided in an insulating layer disposed between the pixel electrode and the counter electrode, and is filled in, for example, a plurality of holes formed by a photolithography method, so that the scattering characteristics of the liquid crystal can be optimized. Thus, it is easy to form a carrier structure, and appropriate electro-optical characteristics can be easily obtained. In addition, since the liquid crystal panel can be manufactured without using a polymerization reaction, contamination of impurities is effectively reduced, and display characteristics and reliability of the liquid crystal panel are improved.

The following examples of the present invention will further clarify such an operation of the present invention, and will further clarify other operations of the present invention.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a partially broken perspective view showing the structure of a main part of a scattering type liquid crystal display device according to an embodiment of the present invention.

In FIG. 1, a scattering type liquid crystal display device 10 comprises:
A glass substrate 11 as an example of a first substrate, and a glass substrate
A pixel electrode 27 provided on the glass substrate 11, a counter substrate 12 as an example of a second substrate disposed opposite to the glass substrate 11, a counter electrode 13 provided on the counter substrate 12, A polyimide film 51 as an example of a liquid crystal holding insulating layer disposed between the electrodes 13, a plurality of holes 52 provided in the polyimide film 51, and a liquid crystal containing a chiral compound filled in the holes 52 61 and. On the glass substrate 11, in addition to the pixel electrode 27, a TFT (thin film transistor) array 20 for driving the pixel electrode 27 is formed. Pixel electrode
A passivation film 28 is provided between the TFT array 27 and the TFT array 20 and the polyimide film 51, and a passivation film 62 is provided between the counter electrode 13 and the polyimide film 51.

In the scattering type liquid crystal display device 10 configured as described above, the portion A including the substrate 11 and the TFT array 20 shown in FIG. 1 and the portion B including the counter substrate 12 and the like are separately formed. Thereafter, it is created by laminating as described later.

First, A including the substrate 11, the TFT array 20, and the like
The procedure for manufacturing the portion will be described below.

FIGS. 2 and 3 are a sectional view and a plan view, respectively, showing the steps of fabricating the TFT array on the substrate 11 in sequence. In these figures and the following description, parts not directly related to the present invention, such as auxiliary capacitances and auxiliary capacitance electrode lines, are omitted for simplification.

First, as shown in FIGS. 2A and 3A, a thin film of tantalum is formed on a glass substrate 11 by a sputtering method, and a gate bus line 22 is formed by a photolithographic method. I do.

Next, as shown in FIGS. 2 (b) and 3 (b),
Silicon nitride film 23 as gate insulating film, undoped amorphous silicon film 24, and n + amorphous silicon film
25 are sequentially formed by a plasma CVD method, and both amorphous silicon films are patterned in an island shape.

Next, as shown in FIGS. 2C and 3C, a source bus line 26 is formed by forming a titanium film by a sputtering method and patterning it with an n + silicon film.

Thereafter, as shown in FIGS. 2D and 3D, an ITO film is formed by a sputtering method and is patterned as the pixel electrode 27. Further, a silicon nitride film is formed on the entire screen by a plasma CVD method and photolithography to form a passivation film 28 for the TFT and each electrode. Note that the passivation film is not shown in FIG.

As shown in FIG. 4, the gate bus line 22 and the source bus line 26 are respectively connected to island-shaped patterns 31 and 32 which are electrode terminals for connecting a driver IC in a peripheral portion of the panel outside the screen. It is connected. still,
In FIG. 4, the area surrounded by the dotted line is the screen area shown in FIG. 3, which is an enlarged view of the area. 33 is a terminal for a counter electrode described later.

Next, as shown in FIG. 5, a polyimide solution is applied on the passivation film 28 by a spinner. After the application, baking is performed at about 250 ° C., and the solvent is removed to form a polyimide film 51. At this time, the thickness of the polyimide film 51 is 5 μm. Next, using a photomask in which a large number of circular patterns are formed, a large number of holes 52 are provided in the polyimide film 51 by photolithography. The mask pattern used in this embodiment is a circle having a diameter of 5 μm and a center-to-center distance of 7.5 μm.
They are installed at m intervals. This circular pattern is provided only on the pixel electrode, and there is no circular pattern on the other bus lines or TFTs.

The panel thus prepared is placed in a vacuum device, and a vacuum environment of about 10 ^-3 Torr is established. In this state, a liquid crystal material mixed with cholesteric nanoate, which is a chiral compound having a function of imparting a revolving property to the arrangement structure of liquid crystal molecules, is dropped on the entire surface of the polyimide film 51.
Next, when the pressure is gradually increased and returned to normal pressure, the liquid crystal is inserted into the holes 52 formed in the polyimide film 51 as shown in FIG.
61 invades. After the pressure is returned to normal pressure, the liquid crystal is rotated on a spinner to remove excess liquid crystal remaining on the polyimide film 51.

Next, as shown in FIG.
On top of this, a passivation film 62 which is a second polyimide film.
Is applied with a spinner, baked, and formed into a film. At this time, the thickness of the polyimide film 62 is 0.5 μm. The film on the electrode terminal portion located at the peripheral portion of the panel is removed by etching.

By the above procedure, the substrate 11, the TFT array
The portion A shown in FIG. 1 including 20 and the like is completed. Next, the counter substrate 12 and the counter electrode 13 bonded to the portion A
The procedure for creating the part B including the following will be described below.

First, as shown in FIG. 7, a light-shielding pattern, that is, a pattern in which only a portion corresponding to a pixel electrode of an opposing TFT substrate has an opening 71 on a counter substrate 12 made of a glass substrate is a chrome film. Form at 72. afterwards,
An ITO film is formed thereon by a sputtering method,
The counter electrode 13 is formed.

Next, a method of bonding the portions A and B completed by the above procedure will be described below.

As shown in FIG. 8, around the portion B,
A thermosetting sealing resin 82 mixed with plastic beads having a diameter of 5 μm is provided by using a screen printing method,
The part A is bonded in a vacuum. At this time, a conductive resin 84 is provided at the four corners of the portion B, and the ITO film constituting the counter electrode 13 shown in FIG. 1 and the counter electrode 13 on the substrate 11 shown in FIG. The electrode electrode lines 33 are connected to each other.

After bonding the A portion and the B portion in this way, a heat treatment is performed to cure the seal resin,
The scattering type liquid crystal display device 10 shown in FIG. 1 is completed.

In order to operate the scattering type liquid crystal display device 10 formed as described above, the driver IC is connected to the gate bus line 22, the source bus line 26 and the source bus line 26 similarly to the current TFT-LCD (liquid crystal display) device. What is necessary is just to mount on the electrode terminal respectively corresponding to the counter electrode 13, and to connect to a drive circuit. As a result, in the scattering type liquid crystal display device 10, the voltage applied between each pixel electrode 27 and the counter electrode 13 in the screen can be controlled.

Therefore, during the operation of the scattering type liquid crystal display device 10, when the applied voltage is small, as shown in FIG. 9 (a), the liquid crystal 61 mixed with the chiral compound in the hole 52 It is in a focal conic state and scatters incident light. When the applied voltage increases, the orientation of the liquid crystal molecules changes as shown in FIG. 9B, and the liquid crystal molecules become transparent to the incident light. An image can be displayed by controlling the degree of scattering and transparency by the applied voltage.

Although the polyimide film 51 is used as the insulating layer in this embodiment, a silicon nitride film or a silicon oxide film formed by a plasma CVD method or the like may be used.

It is not always necessary to drive the TFT, and a simple matrix structure may be used.

[0036]

As described in detail above, according to the present invention, the liquid crystal is filled in a plurality of holes provided in the insulating layer disposed between the pixel electrode and the counter electrode.
It is easy to create a carrier structure that optimizes the scattering characteristics of the liquid crystal, that is, a stable scattering characteristic is easily obtained,
Suitable electro-optical characteristics can be easily obtained. Also,
Since it can be manufactured without using a polymerization reaction, contamination of impurities is effectively reduced, and display characteristics and reliability of the liquid crystal panel are improved.

As a result, according to the present invention, a high-quality image can be displayed, and a highly reliable and inexpensive scattering
The method for manufacturing a liquid crystal display device can be realized.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view showing a main structure of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing a manufacturing process of the TFT array of the liquid crystal display device of FIG.

FIG. 3 is a partially enlarged plan view showing a manufacturing process of a TFT array of the liquid crystal display device of FIG.

FIG. 4 is a schematic plan view for explaining a manufacturing process of the liquid crystal display device of FIG.

FIG. 5 is a partially broken perspective view for explaining a manufacturing process of the liquid crystal display device of FIG.

FIG. 6 is a partially broken perspective view for explaining a manufacturing process of the liquid crystal display device of FIG.

FIG. 7 is a partially enlarged plan view for explaining a manufacturing process of the liquid crystal display device of FIG.

FIG. 8 is a schematic perspective view for explaining a manufacturing process of the liquid crystal display device of FIG.

FIG. 9 is a schematic perspective view for explaining the operation of the liquid crystal display device of FIG.

FIG. 10 is a schematic sectional view for explaining the operation of a conventional liquid crystal display device.

[Explanation of symbols]

 10 Scattering type liquid crystal display 11 Glass substrate 12 Counter substrate 13 Counter electrode 20 TFT array 22 Gate bus line 26 Source bus line 27 Pixel electrode 28, 62 Passivation film 51, 62 Polyimide film 52 Hole 61 Liquid crystal

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-56-97317 (JP, A) JP-A-3-287122 (JP, A) JP-A-4-56920 (JP, A) JP-A-5-97 61017 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G02F 1/1333 G02F 1/1341 G02F 1/136 500

Claims (1)

(57) [Claims] A first electrode formed on a first substrate ;
Form an insulating layer on the electrode and form multiple holes in the insulating layer
Filling the plurality of holes with a liquid crystal containing a chiral compound,
A counter electrode is formed on a second substrate, and the first substrate and the second
Of a scattering type liquid crystal display device manufactured by bonding
A manufacturing method, wherein the first substrate is disposed in a vacuum environment.
The liquid crystal is dropped on the insulating layer in which the plurality of holes are formed.
And return the environment in which the first substrate is placed to normal pressure.
Then, the first substrate is set on a spinner and rotated.
By removing the excess liquid crystal by
Filling the plurality of holes with the liquid crystal;
Manufacturing method of a liquid crystal display device .