JP2001281697A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IPS-type liquid crystal display device of a COA system, which prevents variance of thickness of a liquid crystal layer and can bring out excellent display performance by it, while maintaining high aperture ratio, and to provide its production method. SOLUTION: The liquid crystal display device with which a electric field almost parallel to a principal surface of a first substrate is applied to a liquid crystal layer provided with the first substrate, pixel electrode and a counter electrode formed on the first substrate, active element formed on the first substrate and connected to the pixel electrode, color filter layer formed in the prescribed area on the first substrate, light-shielding layer formed so as to cover the active element on the first substrate, second substrate placed opposite to the first substrate and liquid crystal layer held between the first substrate and the second substrate, is provided. The color filter layer and the light shielding layer are formed by dyeing a color acceptance resin layer placed on the first substrate by the dye of the prescribed color, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a COA (CF on A).
IPS (In-Plane Switch)
and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as a liquid crystal display device utilizing the birefringence effect of a liquid crystal material, the display contrast ratio characteristic of which is less dependent on the viewing angle than a TN type liquid crystal display device, in particular, an IP
The development of S-type liquid crystal display devices has been actively promoted.

An IPS type liquid crystal display device has a structure as shown in FIG. That is, the opposing substrate 1 and the array substrate 2
The structure is the same as that of the TN type liquid crystal display device, in which the liquid crystal 5 is interposed between the liquid crystal display device and the polarizers 15 and 28 are disposed on the opposite sides of the opposing substrates 1 and 2 respectively. The TN type liquid crystal display device is different from the TN type liquid crystal display device in that both the pixel electrode 21 and the counter electrode 22 are provided on the array substrate 2.

In the IPS type liquid crystal display device having such a structure, the TFT element is controlled, and the pixel electrode 21 and the counter electrode 22 are controlled.
A horizontal electric field that is horizontal to the substrate surface is generated between them, thereby controlling the orientation of the liquid crystal molecules 5 and performing optical switching mainly using the birefringence effect of the liquid crystal molecules 5.

That is, in an initial state where no voltage is applied, the liquid crystal molecules 5 are arranged in a direction perpendicular to the direction in which the voltage is applied, but a voltage is applied between the pixel electrode 21 and the counter electrode 22. Then, the liquid crystal molecules 5 are arranged in a direction parallel to the direction in which the voltage is applied. In the configuration shown in FIG.
The two polarizing plates 15 and 28 are arranged so that the transmittance becomes minimum when no voltage is applied, the transmittance increases in proportion to the voltage, and the transmittance becomes maximum at the maximum voltage. This is a so-called normally black mode.

In the operation mode of the TN liquid crystal, the liquid crystal molecules are twisted between the substrates in the off state, and are vertically aligned between the substrates by applying a voltage. Therefore, a transition state occurs at the intermediate potential, and the optical characteristics differ depending on the viewing angle.

On the other hand, the IPS mode is similar to the TN mode in that the birefringence effect is utilized. However, in the off state and the on state, the liquid crystal molecules only rotate while maintaining parallel to the substrate surface. Even if the viewing angle changes, the change in the optical characteristics of the liquid crystal is small, and therefore, there is an advantage that a wide viewing angle can be selected.

However, in the IPS type liquid crystal display device, as described above, since the liquid crystal molecules are always parallel to the substrate surface, if the thickness of the liquid crystal layer changes due to the unevenness on the substrate, the orientation of the liquid crystal molecules is changed. Disturbed, there is a problem that the deterioration of display performance caused by this is significantly larger than that of the TN type.

In addition, as a liquid crystal display device capable of achieving a high aperture ratio because there is no misalignment at the time of assembling the substrates, a COA (CF on Array) type liquid crystal in which a color filter layer is laminated on a TFT element substrate is used. Display devices are also being developed.

On the other hand, on the TFT element, it is necessary to provide a light shielding layer for blocking external light in order to prevent a malfunction.
In the case of a TN type liquid crystal display device, it is common to provide a black resin layer on a TFT element or to provide a black resin layer or a non-transparent metal layer on a substrate facing a TFT element substrate.

[0011] In a COA-type liquid crystal display device,
The color filter pattern that overlaps the pixel electrode
A similar effect can be obtained by extending the region to form a light-shielding layer.

[0012]

SUMMARY OF THE INVENTION However, TFT
When a black resin layer or a color filter layer is laminated on the element, the paste containing the pigment component has a high viscosity at the time of application, so that the inclined surface of the film that is not horizontal to the substrate around the TFT element expands in all directions, that is, The area having the inclined surface is enlarged, and a part of the area extends to the pixel area.

As a result, the thickness of the liquid crystal layer in the vicinity of the pixel after assembling the substrate becomes non-uniform.
In the PS-type liquid crystal display device, the contrast ratio is reduced due to poor alignment. Further, when a black resin layer or a color filter layer is provided on the counter substrate side, the aperture ratio decreases.

The present invention has been made under such circumstances,
Provided is a COA-type IPS-type liquid crystal display device and a method for manufacturing the same, which maintain a high aperture ratio, prevent a change in the thickness of a liquid crystal layer, and thereby exhibit excellent display performance. It is in.

[0015]

In order to solve the above problems, the present invention provides a first substrate, a pixel electrode and a counter electrode formed on the first substrate, An active element formed and connected to the pixel electrode; a color filter layer formed in a predetermined region on the first substrate; and a color filter layer formed on the first substrate so as to cover the active element. A light-shielding layer, a second substrate disposed opposite to the first substrate, and a liquid crystal layer held between the first substrate and the second substrate. 1. A liquid crystal display device in which an electric field substantially parallel to a main surface of one substrate is applied, wherein the color filter layer and the light-shielding layer are formed by a dye-receiving resin layer disposed on the first substrate. A liquid crystal display device characterized by being dyed with a color dye is provided. To.

In such a liquid crystal display device, the color filter layer is formed such that a predetermined region of the dye receiving resin layer is
The color filter may be dyed with a dye having a desired color, and the light-shielding layer may be formed by dyeing a region of the dye-receiving resin layer covering the active element with a black dye.

Dyeing with the dye is carried out by an ink jet method. The dye-receiving resin layer can be made of a transparent photo-curable resin or a transparent thermosetting resin. The light transmittance of the light shielding layer is 6
Desirably less than 0%.

In the liquid crystal display device according to the present invention, the liquid crystal molecules of the liquid crystal layer may be oriented substantially horizontally with respect to the first and second substrate surfaces and substantially parallel to each other.

The pixel electrode for each pixel region is electrically connected to an active element controlled by a scanning line and a signal line via a through hole formed in the dye receiving resin layer for each pixel electrode. Configuration.

Such a liquid crystal display device of the present invention can be driven in a normally black mode in which black display is performed with the potential difference between the pixel electrode and the counter electrode being substantially zero.

The present invention also provides a step of forming an active element on a first substrate, a step of forming a pixel electrode and a counter electrode connected to the active element on the first substrate,
Forming a dye-receiving resin layer on the first substrate;
Dyeing a predetermined region of the dye-receiving resin layer with a dye of a predetermined color constituting a color filter to form a color filter layer; and, in the dye-receiving resin layer, a region covering the active element with a predetermined dye. Forming a light-shielding layer, arranging a second substrate facing the first substrate, and arranging a liquid crystal layer between the first substrate and the second substrate. A method for manufacturing a liquid crystal display device, comprising: applying an electric field substantially parallel to a main surface of the first substrate on the liquid crystal layer.

In the method for manufacturing a liquid crystal display device,
The step of forming the color filter layer is performed by dropping a dye of a predetermined color constituting the color filter into a predetermined region of the dye receiving resin layer by ink-jet, and penetrating the dye receiving resin layer. The step of forming the light-shielding layer can be performed by dropping a black dye by inkjet onto a region of the dye-receiving resin layer that covers the active element, and penetrating the dye-receiving resin layer.

The color filter layer and the light-shielding layer can be formed by dyeing the dye-receiving resin layer and then curing the dye-receiving resin layer by heat treatment or light irradiation.

According to the present invention configured as described above,
The dye-receiving resin layer does not contain a dye, and can be made of a resin having a sufficiently low viscosity and a high leveling property. When the resin layer is applied on the TFT element, the first substrate can be formed even near the unevenness of the TFT element. On the other hand, the surface on which the resin layer is applied becomes smooth, so that the thickness of the liquid crystal layer does not change.

The dye molecules for the color filter and the light-shielding penetrate into the dye-receiving resin layer having a smooth surface as described above, so that no irregularities occur even after dyeing. Therefore, in the liquid crystal display device of the present invention, in particular, it is possible to realize a light-shielding region without unevenness even near the TFT element protruding from the substrate surface,
In the IPS-type liquid crystal display device, it is possible to adopt a COA method capable of realizing a higher aperture ratio. By using such a combination of the IPS type and the COA method, it is possible to obtain a wide viewing angle, high luminance, and excellent display. Properties can be obtained.

[0026]

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

FIG. 1 shows an IPS according to an embodiment of the present invention.
1 schematically shows an array substrate of a liquid crystal display device. In FIG. 1, a pixel electrode 21 and a counter electrode 22 are provided on a transparent resin substrate 20, and scanning lines 23 and signal lines 24 are provided so as to cross each other. Scanning line 23
A TFT 26 is arranged near the intersection of the signal line 24 and the signal line 24. The source electrode 21a of the TFT 26 is connected to the pixel electrode 21, and the drain electrode 24a is connected to the signal line 24.
It is connected to the.

In the array substrate thus configured, a region A surrounded by a dashed line is a light shielding region where a light shielding layer is provided, and a region B surrounded by a dashed line is a color filter provided with a color filter. Area.

FIG. 2 is a sectional view showing the structure of the IPS type liquid crystal display device including the light shielding area A and the color filter area B. In FIG. 2, a dye receiving resin layer 31 is formed on an array substrate 2, and the dye receiving resin layer 31 includes a TFT
The portion corresponding to the light-shielding region A covering the top 26 is dyed with a black pigment to form a light-shielding layer 31a, and the portion of the resin layer 31 corresponding to the color filter region B includes a red dye, a green dye, and a blue dye. It is dyed with a dye to form a red color filter layer, a green color filter layer, and a blue color filter layer. FIG. 2 shows only the red color filter layer 31b.

In FIG. 2, a pixel electrode 21 is formed on the red color filter layer 31b, and this pixel electrode is connected to the TFT 26 through a through hole 32.

As the dye receiving resin layer 31, a thermosetting resin or a photocurable resin can be used. An acrylic polymer or an epoxy polymer can be used as the thermosetting resin, and an acrylic polymer or an epoxy polymer can be used as the photocurable resin.

The thickness of the dye receiving resin layer 31 is 0.1 μm
〜4 μm is preferred. The dyeing of the dye receiving resin layer 31 is preferably performed by an inkjet method.
The ink jet method includes a piezo jet method in which a dye ink droplet is ejected by using vibration of a piezo element, and a pressure change is generated in a nozzle using a bubble (bubble) created by a heater element to eject a dye ink droplet. There is a bubble jet (registered trademark) system.

As the black dye used for dyeing the dye-receiving resin layer 31, an acid dye or the like can be used. As the red dye, an acid dye or the like can be used. As the green dye, an acid dye or the like can be used. And as the blue dye, an acid dye or the like can be used.

Incidentally, a red dye, a green dye or a blue dye can be used instead of the black dye. That is, the light-shielding layer can be an extension of the color filter layer. In any case, the transmittance of the light-shielding layer is preferably less than 60%.

When these dyes are dropped onto a predetermined region of the dye receiving resin layer 31 from the head of the ink jet apparatus, the dye molecules penetrate into the dye receiving resin layer 31 to form a light shielding layer and a color filter layer.

Dye-receiving resin layer 31 dyed with a dye
Is then cured. When the dye receiving resin layer 31 is made of a photocurable resin, the dye receiving resin layer 31
Is cured by light irradiation, and when the dye-receiving resin layer 31 is made of a thermosetting resin, the dye-receiving resin layer 3
1 is cured by heat treatment.

By this light irradiation or heat treatment, the dye permeated into the dye receiving resin layer 31 is fixed. When the dye receiving resin layer 31 is cured by heat treatment, the heat treatment temperature is preferably 150 to 250 ° C., and the heat treatment time is preferably several tens of hours.

Here, the formation process of the light-shielding layer and the color filter layer by the ink-jet dyeing method will be described in detail with reference to FIG.

First, as shown in FIG. 3A, a TFT element 26 is formed on a transparent resin substrate 20. Then, FIG.
As shown in (b), a thermosetting resin or a photocurable resin is coated on the transparent resin substrate 20 on which the TFT elements 26 are formed, and a dye-receiving resin layer layer 41 is formed.

Next, as shown in FIG. 3C, a red dye R, a green dye G, and a blue dye B are sequentially dropped onto a predetermined dye receiving resin layer 41 using an ink jet device 42. Next, a black dye C is provided in a region between the regions where the red dye R, the green dye G, and the blue dye B are respectively dropped.
Is dropped. Each of the dropped dyes has a dye-receiving resin layer 41.
Diffuses and penetrates inside.

Thereafter, the dye permeated into the dye-receiving resin layer 41 is fixed by heat treatment or light irradiation, and the dye-receiving resin layer 41 is cured. As a result, FIG.
As shown in (d), a light-shielding layer 31a dyed with a black dye, a red color filter layer 31b dyed with a red dye, a green color filter layer 31b dyed with a green dye, and a blue color dyed with a blue dye The filter layer 31d is formed.

The light-shielding layer and the color filter layer formed in this manner have a smooth surface because the dye has penetrated into the dye-receiving resin layer 41, and particularly, on the TFT 26 protruding from the substrate 20. The surface of the light-shielding layer formed in the region is also substantially at the same level as the surface of the color filter layer.

On the other hand, in a method of forming a light shielding layer and a color filter layer by patterning a photosensitive resin containing a pigment as in a conventional COA type liquid crystal display device, as shown in FIG. Protrudes, and a large step is generated between the color filter layer 52.

If there is a large step between the light shielding layer 51 and the color filter layer 52, the orientation of the liquid crystal molecules is disturbed as shown in FIG. Significantly deteriorated.

[0045]

As described above, according to the present invention, since the light-shielding layer and the color filter layer are formed by dyeing the dye-receiving resin layer, the surface of the TFT element relative to the first substrate even near the unevenness of the TFT element. The liquid crystal layer becomes smooth, so that the thickness of the liquid crystal layer does not change.

Therefore, in the liquid crystal display device of the present invention, it is possible to realize a light-shielding region without unevenness even in the vicinity of the TFT element protruding from the substrate surface, and the IPS type liquid crystal display device has a higher aperture ratio. It is possible to adopt a COA method that can be realized.
By using a combination of the methods, it is possible to obtain a wide viewing angle, high luminance, and good display characteristics.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an array substrate of an IPS type liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a COA IPS type liquid crystal display device according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a process of forming a light-shielding layer and a color filter layer of a COA-mode IPS-type liquid crystal display device according to an embodiment of the present invention in the order of steps.

FIG. 4 is a cross-sectional view showing a conventional COA IPS type liquid crystal display device.

FIG. 5 is a perspective view for explaining the principle of a normal IPS type liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Counter substrate 2 ... Array substrate 5 ... Liquid crystal molecule 15, 28 ... Polarizer 21 ... Pixel electrode 22 ... Counter electrode 23 ... Scan line 24 ... Signal line 26 ... TFT 31, 41 ... Dye receiving resin layer 31a ... Light shielding layer 31b ... red color filter layer 31c ... green color filter layer 31d ... blue color filter layer 32 ... through hole 42 ... inkjet device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/30 338 G09F 9/30 349B 349 349C G02F 1/136 500 F Term (Reference) 2H048 BA19 BA25 BA27 BA64 BB02 BB44 2H091 FA02Y FA34Y FB04 FB12 FC05 FC22 FC23 GA01 GA13 KA10 LA15 LA19 2H092 GA14 JA24 JA46 JB05 JB51 MA37 NA04 NA07 PA08 PA09 5C094 AA03 AA08 AA10 AA12 AA25 AA43 AA15 EB03 EA03 FB03 GB10 5G435 AA01 AA03 AA17 BB12 BB15 CC09 CC12 FF13 GG12 HH20 KK05

Claims (15)

[Claims] A first substrate; a pixel electrode and a counter electrode formed on the first substrate; an active element formed on the first substrate and connected to the pixel electrode; A color filter layer formed in a predetermined area on the first substrate; a light-shielding layer formed on the first substrate so as to cover the active element; and disposed to face the first substrate. A second substrate, and a liquid crystal layer held between the first substrate and the second substrate, and a liquid crystal for applying an electric field substantially parallel to a main surface of the first substrate to the liquid crystal layer. The display device, wherein the color filter layer and the light-shielding layer are the first layer.
Wherein the dye-receiving resin layer disposed on the substrate is dyed with a dye of a predetermined color. 2. The color filter layer according to claim 1, wherein a predetermined region of the dye-receiving resin layer is dyed with a dye of a desired color constituting a color filter, and the light-shielding layer is formed of the dye-receiving resin layer. 2. The liquid crystal display device according to claim 1, wherein a region covering the active element is dyed with a black dye. 3. The liquid crystal display device according to claim 2, wherein the dyeing is performed by an ink jet method. 4. The liquid crystal display device according to claim 1, wherein said dye receiving resin layer is made of a transparent photocurable resin. 5. The liquid crystal display device according to claim 1, wherein said dye receiving resin layer is made of a transparent thermosetting resin. 6. The liquid crystal display device according to claim 1, wherein the light transmittance of the light shielding layer is less than 60%. 7. The liquid crystal display device according to claim 1, wherein the liquid crystal molecules of the liquid crystal layer are oriented substantially horizontally with respect to the first and second substrate surfaces and substantially parallel to each other. . 8. The pixel electrode for each pixel region is electrically connected to an active element controlled by a scanning line and a signal line via a through hole formed in the dye receiving resin layer for each pixel electrode. The liquid crystal display device according to claim 1, wherein: 9. The liquid crystal display device according to claim 7, wherein black display is performed when a potential difference between said pixel electrode and said counter electrode is substantially zero. 10. A step of forming an active element on a first substrate; a step of forming a pixel electrode and a counter electrode connected to the active element on the first substrate; Forming a dye receiving resin layer thereon; dyeing a predetermined region of the dye receiving resin layer with a dye of a predetermined color constituting a color filter to form a color filter layer; A step of dyeing a region covering the active element with a predetermined dye to form a light-shielding layer, a step of arranging a second substrate facing the first substrate, and a step of arranging the first substrate and the second substrate And a step of disposing a liquid crystal layer therebetween. A method for manufacturing a liquid crystal display device, wherein an electric field substantially parallel to a main surface of the first substrate is applied to the liquid crystal layer. 11. The step of forming the color filter layer comprises: dropping a dye of a predetermined color constituting the color filter onto a predetermined region of the dye receiving resin layer by ink jet; The step of forming the light-shielding layer is performed by infiltrating a black dye, by inkjet, into a region of the dye-receiving resin layer that covers the active element, and by penetrating the dye-receiving resin layer. The method according to claim 10, wherein the method is performed. 12. The method according to claim 10, wherein the dye receiving resin layer is made of a transparent photo-curable resin. 13. The method according to claim 10, wherein the dye receiving resin layer is made of a transparent thermosetting resin. 14. The method according to claim 9, wherein the light transmittance of the light shielding layer is less than 60%. 15. The method for manufacturing a liquid crystal display device according to claim 10, further comprising a step of curing the dye receiving resin layer by heat treatment or light irradiation after dyeing the dye receiving resin layer.