JPH05224189A - Production of scattering type liquid crystal display device of active matrix driving system - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal display device which is stable in performance by preventing remaining of parts which are not polymerized by non-irradiation or insufficient irradiation with UV rays at the time of forming an active matrix liquid crystal display element by synthesizing a monomer or oligomer by irradiation with UV rays and dispersing liquid crystal molecules into a polymer. CONSTITUTION:A liquid crystal material mixture 119 is held between a TFT substrate 111 formed with TFTs 112 and picture element electrodes 113 and a counter substrate 114 having a counter electrode 116 and is sealed by a sealing resin 117. The liquid crystal material mixture 119 is then irradiated with the UV rays for polymn. from the counter substrate 114 side to polymerize the monomer or oligomer in the mixture and to disperse the liquid crystal into the resulted network structure. A transparent plate having a microlens array 1 corresponding one to one to the respective picture element electrodes and a polarizing film 2 is so adhered by an adhesive 11 to the above-mentioned substrate in such a manner that the centers of the picture element electrodes 113 and the respective centers of the microlenses 1 come onto the straight lines perpendicular to the respective planes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an active matrix driving type scattering type liquid crystal display device, and more particularly to a manufacturing method of a liquid crystal display device combining an active matrix driving type using a TFT and a scattering mode by a polymer dispersion type liquid crystal layer.

[0002]

2. Description of the Related Art First, the structure of a conventional TFT-LCD using a polymer dispersed liquid crystal will be described. As shown in the plan view (a) of FIG. 8 and the cross-sectional view (b) of P-P ′ in the plan view, the TFT 71 and the pixel electrode 7 are formed on the glass substrate 70.
2 are provided in a matrix, and the scanning electrode lines 73 for operating the TFTs and the signal electrodes 74 are wired to form a TFT substrate. Then, a passivation film 75 is provided on this TFT substrate. The passivation film 75 is omitted in the plan view. In the figure, 76 is a gate insulating film, 77 is an undoped amorphous silicon film, 78 is an n ⁺ amorphous silicon film, 79 is a source electrode, and 80 is a drain electrode.

The scanning electrodes and the signal electrodes are TFTs.
Wiring is performed in an island pattern, which is an electrode terminal, on the edge portion of the substrate, that is, around the outside of the screen, and the wiring is connected to the driver IC. Referring to FIG. 9, 81 is a scan electrode terminal, 82
Is a signal electrode terminal, and 83 is a counter electrode terminal described later. In addition, the counter substrate side is a plan view (a) of FIG.
As shown in the cross-sectional view (b) of P-P 'in the plan view, a chromium film is formed on the glass substrate 90 by a sputtering method, and then patterned into a pattern 91 indicated by diagonal lines. This has the role of blocking the leakage light from the TFT substrate. 9
Reference numeral 2 is an opening corresponding to both pixel electrodes of the TFT substrate, and this portion serves as an effective display portion. Further on this, the ITO film 93
Is formed on the entire screen to serve as a counter electrode.

In recent years, a TFT-LCD having a structure in which a pixel electrode is spread over the source and gate electrodes via an insulating film has been devised. In any case, a TFT-LCD using amorphous silicon as a semiconductor is used. When the light is emitted onto the TFT channel,
Since the electrical characteristics of the FT change, a method of shielding the upper channel of the TFT from light is necessary.

Referring to FIG. 11, a thermosetting seal resin 102 mixed with plastic beads having a diameter of 10 μm is provided around the counter substrate 101 by a screen printing method, and the TFT substrate 103 and the vacuum substrate described above are provided. I stuck it inside. At this time, the conductive resin 104 is provided at the four corners of the counter substrate, and after bonding so that the ITO film of the counter substrate and the electrode line 105 for the counter electrode of the TFT substrate are connected, heat treatment is performed to remove the sealing resin. The liquid crystal panel is completed by curing.

A cross-sectional view is shown in FIG. 117 is a sealing resin. Plastic beads 118 are arranged as spacers between the substrates to form a gap having a constant thickness between the substrates. A mixture 119 of a polymer monomer or oligomer having a photopolymerizable property and a liquid crystal material is injected into this void and sealed. 111 is a TFT substrate, 112 is a TFT,
113 is a pixel electrode, 120 is a passivation film, 11
4 is a counter substrate, 115 is a light-shielding film, and 116 is a counter electrode.

Next, the liquid crystal panel is irradiated with ultraviolet rays,
Polymerize a polymer monomer or oligomer.
By this polymerization, the polymer and the liquid crystal undergo a phase separation reaction.
At this time, as shown in FIG. 13, the liquid crystal molecules 123 constituting the liquid crystal phase 122 are dispersed in the network structure of the polymer compound 124 and aligned along the interface 125. Since this orientation direction is not regulated, the orientation of liquid crystal molecules in the panel becomes random and scatters the light incident on the panel. 121
Is a transparent electrode.

The scan electrode lines of this liquid crystal panel and
A driver IC is mounted on the electrode terminal corresponding to each of the signal electrode line and the counter electrode line and connected to the drive circuit. The driving method of the panel will be briefly described. Pulse signals are sequentially input to the scan electrode lines from the uppermost stage to operate the TFTs on the respective scan electrode lines. When a video signal is input from the signal electrode at this operation timing, each TFT
A voltage is applied between the pixel electrode connected to the pixel electrode and the counter electrode facing it. When a voltage is applied to the liquid crystal phase,
As shown in FIG. 14, since the liquid crystal molecules are aligned in the direction of the electric field, the scattering effect of light is reduced and the liquid crystal becomes transparent. An image is displayed by controlling the transparent state and the scattering state when no voltage is applied by the applied voltage.

[0009]

In the above-mentioned liquid crystal panel manufacturing process, there is a process of polymerizing the monomer or oligomer of the polymer by irradiating the panel with ultraviolet rays. In the conventional active matrix panel, when ultraviolet rays are irradiated from the counter substrate side, the light shielding pattern (see FIG. 8) blocks the incident light. Therefore, in the conventional active matrix driving type polymer dispersion type liquid crystal display device, there is a portion inside the panel which is not irradiated with ultraviolet rays for polymerization, and the monomer or oligomer in that portion is not polymerized.

This non-polymerized portion becomes a non-display portion of the liquid crystal display device, but with the passage of time of use of the liquid crystal display device, the unpolymerized substance diffuses into the display portion, and the electro-optical characteristics of the display portion change. Therefore, there is a problem in reliability of display quality.

[0011]

SUMMARY OF THE INVENTION The present invention is a thin film transistor (TFT) substrate in which a scanning electrode is formed on one of a plurality of insulating substrates and a plurality of arrays are formed on the scanning electrode. Is provided, a patterned signal electrode line is provided on the pixel electrode, a pixel electrode to which a voltage is applied from the signal electrode line through the TFT is provided, and a passivation film is coated on the pixel electrode. A counter electrode is provided on a substrate, and the substrate provided with the counter electrode and the TFT
A polymer-dispersed liquid crystal layer is prepared by injecting a mixture of a liquid crystal material with an acrylic material or epoxy material or its oligomer having a photopolymerizable polymer monomer between the substrates and irradiating light from the substrate side of the counter electrode. The present invention relates to a method for manufacturing an active matrix driving type scattering type liquid crystal display device, which comprises:

The manufacturing process of the TFT panel of the present invention will be described with reference to the drawings. 4 to 7 are a plan view (a) of the TFT array and a sectional view (b) of P-P 'in the plan view, which are sequentially shown along the process, and will be described with reference to this drawing. Note that parts such as the auxiliary capacitor and the auxiliary capacitor electrode line which are not directly related to the present invention are omitted. First, referring to FIG. 4, a thin film of tantalum is formed on a glass substrate 30 by a sputtering method, and a scanning electrode 31 is formed by using a photolithographic method.

Here, examples of the substrate include quartz in addition to the above-mentioned glass, and glass can be preferably applied. As the scanning electrode material, aluminum, chromium or the like is preferably applied in addition to the tantalum. Next, referring to FIG. 5, a silicon nitride film 41 that is a gate insulating film, an undoped amorphous silicon film 42, and an n ⁺ amorphous silicon film 43 are sequentially formed by a plasma CVD method, and both amorphous silicon films are formed into island shapes. Pattern.

Next, referring to FIG. 6, a signal electrode, that is, a titanium film 51 which is a source bus line sample is formed by a sputtering method, and is patterned together with an n ⁺ silicon film to form a signal electrode line. Next, referring to the plan view (a) of the TFT array of FIG. 7 and the cross-sectional view (b) of P-P 'in the plan view, an ITO film is formed by a sputtering method,
The pixel electrode 61 is patterned. Then, a silicon nitride film is formed on the entire screen to form the passivation film 62.

As the TFT, in addition to the amorphous silicon type, a polysilicon type or the like can be cited. The passivation film is not limited to the silicon nitride film used here,
It may be a polymer resin film such as a silicon oxide film or a polyimide film. On the opposite substrate side, IT is first placed on the glass substrate.
A film of O is formed by a sputtering method to form a counter electrode. No light-shielding film is formed.

As the counter substrate material, tin oxide or indium oxide is applied in addition to the ITO film, and the ITO film is preferable. Counter substrate and TFT manufactured in this way
The substrates are attached to each other with a sealing resin sandwiching plastic beads having a diameter of about 10 μm. Then, a mixture of a monomer or oligomer and a liquid crystal material, which are polymerizable by light such as ultraviolet rays, is injected from an injection port which is formed by opening a part of the seal resin pattern in advance, and the injection port is sealed with resin.

After the injection, light such as ultraviolet rays is irradiated from the counter substrate side to polymerize the monomer or oligomer to form a polymer dispersion type liquid crystal layer. Here, examples of the monomer or oligomer having a polymerizable property by light such as ultraviolet rays include acrylic materials and epoxy materials, and acrylic materials are preferably applied. Further, examples of the liquid crystal material include cyanophenylcyclohexane-based, cyanobiphenyl-based, fluorine-based, and tolan-based materials.

Next, as shown in FIG. 1, the microlens array 1 was attached on the counter substrate with an adhesive 11 so that the center of the microlens corresponded to a predetermined position of the pixel electrode and irradiated. Parallel light is focused on the pixel electrode, and TFT
Avoid direct light on the channel. After that, the image is displayed on the liquid crystal display device by the driving IC and the driving circuit as in the conventional method.

As a further preferable condition, as shown in FIG. 1, the microlens array 1 is provided on the counter substrate with the adhesive 1.
1 is attached so that the center of the microlens corresponds to a predetermined position of the pixel electrode, and the irradiated parallel light is focused on the pixel electrode so that the light is not directly irradiated onto the channel of the TFT. At this time, it is appropriate to set the size of the microlens to the size of the pixel pitch. As adhesives, Loctite (350), Three Bond (300
0 series), Sony Chemical (17A, 19A), etc.

Further, as shown in FIG. 2, it is also preferable to form the light shielding film 2 on the microlens array 1 by using a photolithographic method. At this time, examples of the material of the film include a metal film of chromium, aluminum, titanium, molybdenum, and tantalum, or a black resin film such as an acrylic resin, a polyimide resin, or a polyamide resin mixed with carbon black or a black pigment.

The position of the microlens is set as shown in FIG.
As shown in FIG. 3, the microlens array 1 is attached to the counter substrate with an adhesive 11 so that the center of the microlens corresponds to a predetermined position of the pixel electrode. Is not directly illuminated on the TFT channel. This is because the incident light may be directly transmitted or scattered and transmitted in the gap between the lenses, and may not be condensed by the lenses.

As a method of obtaining the same effect without applying a microlens, a thermosetting sealing resin 302 is screen-printed on a light-shielding film substrate 300 having a light-shielding film 301 formed of chromium as shown in FIG. We suggest a method of pasting from the side. As for the material and thickness of the light-shielding film, the same conditions as in the case of the microlens can be applied.

At this time, the bonding position is determined so that the light-shielding film shields light from the area other than the pixel electrodes on the TFT substrate. Then, heat treatment is performed to cure the seal resin and complete the liquid crystal panel. An outline of the structure of the completed liquid crystal panel is shown in a plan view (a) of FIG. 16 and a cross-sectional view (b) of P-P 'in the plan view.

The feature of this method is that the light-shielding film 301 is not formed on the counter substrate but is formed on the light-shielding film substrate 300, and the liquid crystal layer is formed and then bonded.

[0025]

By using the above means, it is possible to substantially eliminate unpolymerized residual substances in the panel, and as a result, it is possible to provide an active matrix drive type liquid crystal display device having high display quality and high reliability. ..

[0026]

【Example】

Example 1 The manufacturing process of the TFT panel of the present invention will be described. 4 to 7 show the manufacturing process, and FIG. 1 is a schematic plan view and sectional view of the completed panel. 4 to 7 show T
A plan view (a) of the FT array and a cross-sectional view (b) of P-P 'in the plan view are sequentially shown along the process, and will be described with reference to this figure. Note that parts such as the auxiliary capacitor and the auxiliary capacitor electrode line which are not directly related to the present invention are omitted. First, referring to FIG. 4, a thin film of tantalum is formed on a glass substrate 30 by a sputtering method, and a scanning electrode 31 is formed by using a photolithographic method.

Next, referring to FIG. 5, a silicon nitride film 41 which is a gate insulating film, an undoped amorphous silicon film 42, and an n ⁺ amorphous silicon film 43 are sequentially formed by a plasma CVD method, and both amorphous silicon films are formed. Pattern in an island shape. Next, referring to FIG. 6, a signal electrode, that is, a titanium film 5 as a source bus line sample.
1 is formed by a sputtering method and is patterned together with an n ⁺ silicon film to form a signal electrode line.

Next, referring to the plan view (a) of the TFT array of FIG. 7 and the cross-sectional view (b) of P-P 'in the plan view, the ITO is shown.
A film is formed by a sputtering method and patterned as the pixel electrode 61. Then, a silicon nitride film is formed on the entire screen to form the passivation film 62. On the counter substrate side, ITO is first deposited on the glass substrate by a sputtering method to form a counter electrode. No light-shielding film is formed.

The counter substrate and the TFT manufactured in this way
The substrates are attached to each other with a sealing resin, with plastic beads having a diameter of 10 μm interposed therebetween. Then, from the injection port provided by opening a part of the seal resin pattern in advance,
UV-polymerizable polymer (acrylic) monomer and liquid crystal material (cyanophenylcyclohexane)
The mixture is injected and the injection port is sealed with resin.

After the injection, ultraviolet rays are irradiated from the side of the counter substrate,
The monomer is polymerized to form a polymer dispersed liquid crystal layer. Next, as shown in FIG. 1, the microlens array 1 is attached onto the counter substrate using an adhesive 11 so that the center of the microlens corresponds to a predetermined position of the pixel electrode.
The irradiated parallel light is condensed on the pixel electrode so that the light is not directly irradiated on the channel of the TFT.

After that, the driving IC is used as in the conventional method.
And the driving circuit displays an image on the liquid crystal display device. Next, the electro-optical characteristics of the display device manufactured by the manufacturing method of this embodiment and the display device manufactured by the conventional method were compared. In the initial stage, no great difference was found between the two, but after 1000 hours, the display device of the present invention showed remarkably good results. In the conventional display device, this is because the unpolymerized substance diffuses into the display portion as the liquid crystal display device is used.
It is considered that the electro-optical characteristics of the display part have changed.

Example 2 The manufacturing process of the TFT panel of Example 2 was the same as that of Example 1 up to the step of attaching the microlens array. Then, as shown in FIG. 2, a light shielding film 2 is formed on the microlens array 1 by using a photolithographic method. At this time, the material of the film is chrome, and the film thickness is about 13
It was 00Å.

After that, the driving IC is used as in the conventional method.
And the driving circuit displayed an image on the liquid crystal display device.
Next, the electro-optical characteristics of the display device manufactured by the manufacturing method of this embodiment and the display device manufactured by the conventional method were compared. Example 1
Similarly to the above, a large difference was not found between the two in the initial stage, but after 1000 hours, the display device of the present invention showed remarkably good characteristics. It is considered that this is because, in the display device of the conventional method, the unpolymerized substance diffused into the display portion with the lapse of time of use of the liquid crystal display device, and the electro-optical characteristics of the display portion changed.

Example 3 The steps of manufacturing the TFT panel of Example 3 were performed in the same manner as in Example 1 up to the step of forming the polymer dispersed liquid crystal layer. Next, as shown in FIG. 3, the microlens array 1 is attached to the counter substrate with an adhesive 11 so that the center of the microlens corresponds to a predetermined position of the pixel electrode. The gap between the lenses is the TFT
Avoid being directly illuminated on the channel. This is because the incident light may be directly transmitted or scattered and transmitted in the gap between the lenses, and may not be condensed by the lenses.

After that, the driving IC is used as in the conventional method.
And the driving circuit displayed an image on the liquid crystal display device.
Next, the electro-optical characteristics of the display device manufactured by the manufacturing method of this embodiment and the display device manufactured by the conventional method were compared. Example 1
Similarly to the above, a large difference was not found between the two in the initial stage, but after 1000 hours, the display device of the present invention showed remarkably good characteristics. It is considered that this is because, in the display device of the conventional method, the unpolymerized substance diffused into the display portion with the lapse of time of use of the liquid crystal display device, and the electro-optical characteristics of the display portion changed.

Example 4 The manufacturing steps of the TFT panel of Example 4 were performed in the same manner as in Example 1 up to the step of forming the polymer dispersed liquid crystal layer. Next, as shown in FIG. 15, a thermosetting sealing resin 302 is applied to the light-shielding film substrate 300 on which the light-shielding film 301 is formed of chromium.
Is screen-printed and bonded from the counter substrate side. At this time, the bonding position is determined such that the light-shielding film shields light from the area other than the pixel electrodes on the TFT substrate.

Then, heat treatment is carried out to cure the sealing resin to complete the liquid crystal panel. An outline of the structure of the completed liquid crystal panel is shown in a plan view (a) of FIG. 16 and a cross-sectional view (b) of P-P 'in the plan view. The feature of this embodiment is that the light shielding film 301 is not formed on the counter substrate but is formed on the light shielding film substrate 300, and the liquid crystal layer is formed and then bonded.

After that, the driving IC is used as in the conventional method.
And the driving circuit displayed an image on the liquid crystal display device.
Next, the electro-optical characteristics of the display device manufactured by the manufacturing method of this embodiment and the display device manufactured by the conventional method were compared. Example 1
Similarly to the above, a large difference was not found between the two in the initial stage, but after 1000 hours, the display device of the present invention showed remarkably good characteristics. It is considered that, in the display device of the conventional method, the unpolymerized substance diffused into the display portion with the passage of time of use of the liquid crystal display device, and the electro-optical characteristics of the display portion changed.

[0039]

The present invention can provide an active matrix drive type scattering type liquid crystal display device capable of displaying a high quality image with high reliability, which cannot be achieved by the conventional method.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a display device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a display device in an example of the present invention.

FIG. 3 is a schematic configuration diagram of a display device in an example of the present invention.

FIG. 4 is a diagram illustrating a manufacturing process of the liquid crystal display device according to the embodiment of the present invention.

FIG. 5 is a diagram illustrating a manufacturing process of the liquid crystal display device according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating a manufacturing process of the liquid crystal display device in the example of the present invention.

FIG. 7 is a diagram illustrating a manufacturing process of the liquid crystal display device in the example of the present invention.

FIG. 8 is a diagram illustrating a manufacturing process of a conventional liquid crystal display device.

FIG. 9 is a diagram illustrating an arrangement state of scan electrode terminals of a conventional liquid crystal display device.

FIG. 10 is a diagram illustrating a shielding film-shaped substrate portion of a conventional liquid crystal display device.

FIG. 11 is a diagram for explaining the pasting of a TFT substrate and a counter electrode of a conventional liquid crystal display device.

FIG. 12 is a diagram illustrating the pasting of a conventional liquid crystal display device.

FIG. 13 is a diagram illustrating an operating principle of a polymer dispersion type liquid crystal mode.

FIG. 14 is a diagram illustrating an operation principle of a polymer dispersion type liquid crystal mode.

FIG. 15 is a diagram illustrating an electrode pattern of a liquid crystal display device according to an example of the present invention.

FIG. 16 is a schematic configuration diagram of a display device in an example of the present invention.

[Explanation of symbols]

1 Microlens Array 2, 115, 301 Light-shielding Film 11 Adhesive 30, 70, 90 Glass Substrate 31, 73 Scanning Electrode 41 Silicon Nitride Film 42, 77 Undoped Amorphous Silicon Film 43, 78 n ⁺ Amorphous Silicon Film 51 Titanium Film 61 , 72, 113 Pixel electrodes 62, 75, 120 Passivation film 71, 112 TFT 74 Signal electrode 76 Gate insulating film 79 Source electrode 80 Drain electrode 81 Scan electrode terminal 82 Signal electrode terminal 83 Counter electrode terminal 91 Pattern 92 Effective display area 93 ITO Membrane 101, 114 Counter substrate 102, 117 Seal resin 103, 111 TFT substrate 104 Conductive resin 105 Counter electrode electrode wire 116 Counter electrode 118 Plastic beads 119 Liquid crystal material mixture 121 Transparent electrode 122 Liquid crystal phase 23 liquid crystal molecules 124 polymeric compound 125 interface 300 light shielding film substrate 302 thermosetting sealing resin

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shinji Shimada 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation

Claims (6)

[Claims] 1. A thin film transistor (TFT) substrate having scan electrodes formed on one of a plurality of insulating substrates and having a plurality of arrays formed on the scan electrodes, and a pattern formed thereon. TF
A pixel electrode to which a voltage is applied from the signal electrode line via T is provided, a passivation film is covered on the pixel electrode, and a counter electrode is provided on the other substrate, and a substrate provided with the counter electrode is provided. A monomer of a photopolymerizable polymer having a photopolymerizable property is injected into the TFT substrate, and a mixture of an acrylic material or an epoxy material or an oligomer thereof and a liquid crystal material is injected, and light is irradiated from the substrate side of the counter electrode to disperse the polymer. A method of manufacturing an active matrix driving type scattering liquid crystal display device, which comprises forming a liquid crystal layer. 2. A microlens array, in which microlenses are formed so as to correspond to respective pixel electrodes of the substrate on which the TFT array is formed, is provided on the substrate on which the counter electrodes are provided. The manufacturing method described in. 3. The manufacturing method according to claim 2, wherein the light-shielding film is patterned on the microlens array. 4. The microlenses are attached so that the gaps between the microlenses deviate from the vertical line of the channel of the TFT, and the centers of the lenses are close to the approximate centers of the pixel electrodes. The manufacturing method described in any one of the items. 5. The manufacturing method according to claim 1, wherein a light-shielding film is provided on the surface of the counter electrode opposite to the electrode of the substrate. 6. The shielding film is a film selected from metal films of chromium, aluminum, titanium, molybdenum and tantalum and carbon black, an acrylic resin mixed with a black pigment, or a black resin film of a polyimide resin. The manufacturing method described in the section.