JPH08334755A - Production of electrode substrate for liquid crystal display device and liquid crystal display device formed by using the same - Google Patents

Abstract

PURPOSE: To make it possible to prevent the degradation in the yield of a thin-film transistor(TFT) substrate by the shape defect of color filters by forming color filter coloring layers having notches at ends in such a manner that drain electrodes are partly exposed. CONSTITUTION: Adhesives are applied on the TFT forming surface side of the electrode substrate 16 and thereafter, a transfer sheet having the color filters formed with the notches to expose part of the drain electrodes at the corner parts of the ends on a supporting sheet is stuck to the substrate in such a manner that the color filters and the TFT forming surface face each other. Next, the adhesives on the light transparent parts are photoset by irradiation with UV rays and thereafter, the supporting sheet is peeled, by which color filters are transferred and formed on the electrode substrate 16. Next, a transparent conductive film is formed over the entire surface of the TFT forming surface side after the removal of the unexposed and uncured adhesives and thereafter, this film is patterned to prescribed shapes, by which pixel electrodes 12 consisting of the transparent conductive films electrically connected to the drain electrode parts exposed from the notched parts of the color filters are formed.

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 electrode substrate used in an active matrix type liquid crystal display device, and an active matrix type liquid crystal display device using the electrode substrate manufactured by the manufacturing method of the present invention.

[0002]

2. Description of the Related Art The following structure has been widely adopted as a typical structure of an active matrix type liquid crystal display device. That is, as shown in FIG. 12, a thin film transistor 15 (hereinafter, referred to as T
FT15), an element composed of a diode and a capacitor, a wiring, and a pixel electrode 12 composed of a transparent conductive film such as ITO (Indium Tin Oxide) and the like, and a thin film transistor electrode substrate C having an alignment film 13 on its surface, glass, etc. On the transparent substrate 8'of, a light-shielding film 11 for concealing the above-mentioned element part and wiring part, a color filter composed of the colored layer 3 and the like are formed, and a counter electrode 10 and an alignment film 13 composed of a transparent conductive film are formed. The electrode substrate D to have is separately prepared. Thereafter, the electrode substrate D on which the color filter is formed and the thin film transistor electrode substrate C are made to face each other with a certain distance, and the liquid crystal 19 is filled between the both electrode substrates and bonded so as to seal the liquid crystal display device. The structure is 20. Note that FIG. 12 simply shows a structural example of a conventional liquid crystal display device, and is a simplified diagram for convenience of explanation.

However, in this conventional structure,
Since there is a misalignment between the two electrode substrates facing each other, it is necessary to design the width of the light-shielding film 11 to be larger by an amount corresponding to the bonding accuracy, and thus the area of the color filter becomes smaller and the pixel for the entire screen becomes smaller. However, there is a problem in that the area occupied by (aperture ratio) decreases and the screen display becomes dark. Further, in the above-described structure, since the overlapping portion of the colored layer 3 serving as a color filter and the light shielding film 11 and the TFT 15 portion have a convex shape, the alignment film is formed at that portion.
There was a step at 13. When both electrode substrates with steps are pasted together facing each other, the alignment of liquid crystal molecules becomes uneven at the step during the rubbing process, resulting in poor alignment, resulting in poor display. There was also a problem of significantly deteriorating. To solve this problem,
For example, as disclosed in Japanese Patent Laid-Open No. 4-253028, a method of improving the aperture ratio by forming a color filter on a thin film transistor electrode substrate on which a TFT or the like is formed and smoothing an alignment film is proposed. Was there.

[0004]

In the method of forming a color filter directly on the thin film transistor electrode substrate proposed above, the three colors of red (R), green (G) and blue (B) are divided into three times. Since the color filter is patterned by the spin coating method or the roll coating method, there is a problem that the number of steps is large and the efficiency is low. Further, in the above coating method, the formed color filter has coating unevenness in which the coating film thickness is partially different, uneven streaks in the coating film thickness are different, and white unevenness in which a partially unpatterned portion is formed. There is also a problem that a defect is likely to occur and the yield of the thin film transistor electrode substrate is deteriorated, and the thin film transistor electrode substrate formed with difficulty is not utilized. The present invention aims to remedy the above problems.

[0005]

That is, the present invention provides a method of manufacturing an electrode substrate for an active matrix type liquid crystal display device, comprising: a thin film transistor forming electrode substrate having a thin film transistor and wiring formed on a transparent substrate. On the thin film transistor forming surface side, a non-heated ultraviolet curable adhesive that is transparent at the time of curing is applied, and a color filter formed with a notch at an edge corner to partially expose the drain electrode of the thin film transistor The transfer sheet having the above is attached so that the color filter and the thin film transistor forming surface are opposed to each other, and thereafter, ultraviolet rays are irradiated from the thin film transistor non-forming surface side of the electrode substrate to bond the light transmitting portion of the electrode substrate. After the agent is photocured, the support sheet is peeled off to cover the electrode substrate. -Transfer forming a filter, after removing the unexposed and uncured adhesive on the element and the wiring, after forming a transparent conductive film on the entire thin film transistor formation surface side of the electrode substrate, patterning it into a predetermined shape, A pixel electrode made of a transparent conductive film, which is electrically connected to the drain electrode portion exposed from the cutout portion of the color filter, is formed, and a light shielding film that covers at least the thin film transistor region and the wiring region is formed in a desired shape. Forming a protective film on the thin film transistor forming surface side of the thin film transistor forming electrode substrate, and providing a method for manufacturing an electrode substrate for an active matrix type liquid crystal display device, comprising: It is a solution to the problem.

The present invention will be described below with reference to the drawings.
In the present invention, when manufacturing an electrode substrate for a liquid crystal display device, a transfer sheet in which a color filter composed of three colors of red (R), green (G) and blue (B) is formed on a support sheet 1 is prepared. , A color filter of three colors of red (R), green (G), and blue (B) on a transfer sheet is transferred onto an electrode substrate on which a thin film transistor or the like is formed.

Therefore, first, as shown in the example of FIG.
A transfer sheet 18 in which a color filter coloring layer 3 of three colors of red (R), green (G), and blue (B) is formed on the support sheet 1 via the release layer 2 is prepared. Note that the figure
As shown in the plan view of 10, the color filter coloring layer 3
To expose the drain electrode 5 of the TFT partially when transferred onto an electrode substrate on which a thin film transistor or the like is formed.
It is formed so as to have a notch 17 at its end, and the explanatory view shown below shows a cross section taken along line XX in FIG. 10. It should be noted that the position and size of the notch 17 are not limited to those shown in FIG. 10, and it can be said that it is desirable to set them appropriately according to the specifications of the electrode substrate for a liquid crystal display device. Further, as the material of the support sheet 1, 42 alloy (iron-nickel alloy) or steel material (aluminum killed material)
It has been proposed by the applicant of the present application to use the above.

On the other hand, as shown in the example of FIG. 2, a T made up of a source electrode 4, a drain electrode 5, a gate electrode 6 and the like is formed on a transparent substrate 8 such as a glass substrate by a known method.
A substrate (hereinafter referred to as a TFT forming electrode substrate 16) on which a TFT circuit including an element made of FT15 and a capacitor and a wiring is formed is obtained. In FIG. 2, the area of the opening 7 is a portion that becomes a pixel of red (R), green (G), and blue (B) by forming a color filter as described later, and is a light transmitting portion.

Next, as shown in FIG. 3, the surface of the TFT forming electrode substrate 16 on which the TFT 15 is formed and the surface of the transfer sheet 18 on which the colored layer 3 is formed are opposed to each other to control the position of the transfer sheet 18. While superposing it on the TFT forming electrode substrate 16. At that time, as shown in FIG.
The non-heated ultraviolet-curable adhesive layer 9 that is transparent when cured is formed between the transfer sheet 18 and the transfer sheet 18.

It should be noted that it is desirable that foreign matters such as bubbles are not generated in the adhesive layer 9 during the superposition.
Therefore, the inventors of the present invention, for example, use a roll press to form the TFT forming electrode substrate 16 as described in Examples described later.
And the transfer sheet 18 were superposed. That is, the figure
As shown in 13, after the liquid adhesive 21 is dropped on the surface of the TFT forming electrode substrate 16 on which the TFT 15 is formed, the transfer sheet 18 is aligned and superposed on the TFT forming electrode substrate 16, and at the same time, by a roll press 22 or the like. By applying pressure, the dropped adhesive 21 is spread and the excess adhesive and air bubbles are pushed out, and the two are superposed.

Next, as shown in FIG. 4, ultraviolet rays are irradiated from the TFT non-forming surface side of the TFT forming electrode substrate 16 to photo-cure the adhesive layer 9'of the opening 7. As a result, the colored layer 3 is bonded to the TFT forming electrode substrate 16. The portion of the adhesive layer 9 on the elements, wirings and the like shields the ultraviolet rays applied to the elements, wirings and the like, so that it is unexposed and is not photocured.

Next, as shown in FIG. 5, the support sheet 1 is peeled off together with the peeling layer 2 to form the TFT forming electrode substrate 16
After the color filter colored layer 3 is formed thereon, as shown in FIG. 6, the unexposed and uncured adhesive layer 9 on the elements, wirings and the like is washed and washed with an alkaline solution or the like.

Next, a transparent conductive film, for example, an ITO film is formed on the entire surface of the TFT forming electrode substrate 16 on which the TFT is formed, and then the ITO film is etched by a photolithography method or the like to give a predetermined pattern as shown in FIG. A transparent pixel electrode 12 made of ITO patterned in a shape is obtained. The pixel electrode 12 and the drain electrode 5 of the TFT are electrically connected to each other at the notch 17 of the colored layer 3 shown in FIG.

Next, using a photolithography method,
As shown in FIG. 8, a light shielding film 11 that covers at least the element and the wiring is formed in a desired shape. In addition, as the role of the light shielding film 11,
It has a role of preventing light from entering a device such as a TFT, making the contour of each pixel clear and improving the contrast. Therefore, it can be said that it is desirable that the light-shielding film 11 is formed so as to have an overlap in each pixel portion, that is, in the edge region of each colored layer 3, as shown in FIG.

Further, the light-shielding film 11 is appropriately adjusted in thickness so as not to cause a step difference between the surface of the pixel electrode 12 and the surface of the pixel electrode 12, and the surface of the light-shielding film 11 and the surface of the pixel electrode 12 is smooth. It is desirable to get a face. Further, the light-shielding film 11 prevents an electrical short circuit between the adjacent pixel electrodes 12,
It can be said that it is desirable to use a non-conductive photosensitive resin or the like having a light-shielding property by containing a pigment.

Next, as shown in FIG. 9, in order to protect the TFT 15 from moisture and the like, a protective film 14 is formed on the surface of the TFT forming electrode substrate 16 to form an electrode substrate for an active matrix type liquid crystal display device having a color filter. I will get it.

Next, the active matrix type liquid crystal display device shown in FIG. 11 is obtained by using the above-mentioned electrode substrate for an active matrix type liquid crystal display device manufactured according to the present invention. That is, ITO is formed on the transparent substrate 8 '.
An electrode substrate A having a counter electrode 10 and an alignment film 13 formed of a transparent conductive film such as the above, and an electrode substrate B for an active matrix type liquid crystal display device having the alignment film 13 manufactured by the present invention described above, The liquid crystal 19 is filled between the electrode substrates so that they are opposed to each other with a certain distance therebetween, and the liquid crystal 19 is pasted so as to seal the active matrix type liquid crystal display device 20.
It is assumed that. It should be noted that FIG. 11 simply shows a structural example of the liquid crystal display device according to the present invention, and is a simplified diagram for convenience of explanation.

[0018]

According to the present invention, since the color filter is transferred and formed on the TFT forming electrode substrate from the transfer sheet prepared in advance, the problem that has occurred in the conventional method, that is, each color of the colored layer 3 is sequentially formed on the TFT forming electrode. It is possible to prevent the problem that the yield of the TFT substrate is reduced due to defective formation of the color filter when the TFT is directly formed on the substrate. Further, the method of collectively forming the color filters on the TFT-forming electrode substrate by the transfer sheet requires less steps than the conventional method, and thus it can be said that the production efficiency can be improved.

In addition, since the TFT forming electrode substrate manufactured according to the present invention can have a substantially smooth surface between the light shielding film surface and the pixel electrode surface, the alignment film surface formed on the TFT forming electrode substrate is also flat. Can be realized. Therefore, when an active matrix type liquid crystal display device electrode substrate manufactured according to the present invention is used to form a liquid crystal display device, a rubbing process for uniformly orienting liquid crystal molecules is surely performed, resulting in poor liquid crystal alignment. And a liquid crystal display device with good display quality can be obtained.

[0020]

EXAMPLE An example of a method of manufacturing an electrode substrate for an active matrix type liquid crystal display device according to the present invention will be shown and further described below. <Example> FIG. 1 shows an example of a transfer sheet 18 used in the present invention. A release layer 2 made of, for example, photocurable polyvinyl alcohol is formed on the support sheet 1, and three colored layers 3R, 3G, and 3B (hereinafter, simply referred to as the colored layer 3) are adjacent to each other on the release layer 2. Thus, the color filter layer formed in a plane is formed.

The supporting sheet 1 uses 42 alloy (iron-nickel alloy, nickel 42% by weight, balance iron) and has a thickness of 110.
μm. In addition, each colored layer 3 is provided on the support sheet 1.
Since it is desirable to provide alignment marks for alignment during formation of R, 3G, and 3B, and alignment between the colored layer 3 and the TFT forming electrode substrate 16.
Prior to the formation of the colored layer 3, an alignment mark was formed on a predetermined portion of the support sheet 1 before forming the release layer 2 by a photolithography method or laser light.

The thickness of the release layer 2 made of photocurable polyvinyl alcohol, which adheres well to the support sheet 1 and has good releasability from the colored layer 3, is about 10 μm, and the surface smoothness is about 0.1 μm. did. The release layer 2 is formed by applying a mixture of polyvinyl alcohol and a photocrosslinking agent such as dichromate, chromate, or diazo compound evenly on the support sheet 1 and irradiating it with ultraviolet rays while heating. It was formed by curing.

A colored layer 3 is formed on the cured release layer 2.
It was formed by a pigment dispersion method using a known photolithography method. As shown in FIG. 10, the colored layer 3 is formed to have a notch 17 at an end corner so as to expose the drain electrode 5 constituting the TFT 15 at the time of transfer to a TFT forming electrode substrate 16 described later. did. Further, as a method for forming the colored layer 3, any of conventionally known photolithography method, printing method, electrodeposition method and the like can be adopted. As the photolithography method, in addition to the pigment dispersion method, A dyeing method is also possible. If the colored layer 3 is formed into an inverse taper shape when viewed from the supporting sheet 1, it becomes a forward taper with respect to the TFT forming electrode substrate 16 when transferred to the TFT forming electrode substrate 16, and the pixel electrode 12 to be described later is formed. It can be said that it is desirable because it can prevent disconnection of the pixel electrode 12 during formation.

The transfer sheet 18 created as described above
A method of forming a color filter on the TFT forming electrode substrate 16 by using will be described below. As shown in FIG. 2, the TFT 15 is formed on the transparent substrate 8 made of glass by a known method.
Then, an element and wiring made of a capacitor and the like were formed to obtain a TFT forming electrode substrate 16.

Then, as shown in FIG. 3, the surface of the TFT forming electrode substrate 16 on which the TFT 15 is formed and the surface of the transfer sheet 18 on which the colored layer 3 is formed are opposed to each other to control the position of the transfer sheet 18. On the other hand, it was superposed on the TFT forming electrode substrate 16. At this time, as shown in FIG.
An unheated UV-curable adhesive layer 9 that was transparent at the time of curing was formed between 16 and the transfer sheet 18.

At this time, as shown in FIG. 13, for example, a transparent UV-curable acrylate resin is dropped as an adhesive 21 on the surface of the TFT forming electrode substrate 16 on which the TFT 15 is formed, and then the transfer sheet 18 is aligned. While doing so, it was superposed on the TFT-forming electrode substrate 16 with a roll press 22 at a pressure of 5 kg / cm ² .

Next, as shown in FIG. 4, ultraviolet rays are radiated from the TFT non-forming surface side to photo-cure the adhesive in the opening 7 portion excluding the element and the wiring portion, and the TFT forming electrode substrate 16 is formed. The colored layer 3 was adhered. At this time, as described above, the portion of the adhesive layer 9 on the element and the wiring shields the ultraviolet rays applied to the TFT 15 and the wiring, so that it is not exposed and does not photo-cur.

Next, as shown in FIG. 5, after removing the support sheet 1 having the release layer 2, the TFT forming electrode substrate 16 having the adhesive layer 9'at the opening 7 site cured is washed with an alkaline solution or the like. The unexposed uncured adhesive was removed. As a result, as shown in FIG. 6, the unexposed and uncured adhesive layer 9 on the element and the wiring is washed away, and the surfaces of the TFT 15 and the wiring appear.

Next, the ITO film is sputtered and the T film is removed.
It was vapor-deposited and formed on the entire surface of the FT forming electrode substrate 16 on the side where the TFT was formed, and this was etched by using a photolithography method or the like. Thus, as shown in FIG. 7, the pixel electrode 12 patterned into a predetermined shape was formed on the color filter (coloring layer 3). The pixel electrode 12 was electrically connected to the drain electrode 5 in the cutout 17 region of the colored layer 3 described above.

Then, as shown in FIG. 8, a light-shielding film 11 was formed in a desired shape so as to cover the elements and wirings with an appropriate thickness. As described above, the light-shielding film 11 is made of a non-conductive photosensitive resin and is formed at a predetermined site by a photolithography method or the like, and pigments such as red, blue, yellow, and violet in the resin. The light-shielding property is imparted by appropriately adding. In addition, the light shielding film 11 is
The film thickness is appropriately adjusted within a range that does not impair the light shielding property so that a step with the surface of the pixel electrode 12 does not occur, and the surface of the light shielding film 11 and the pixel electrode
A smooth surface was obtained with 12 surfaces.

Next, as shown in FIG. 9, a protective film 14 was formed on the TFT formation surface side of the TFT formation electrode substrate 16 to obtain an active matrix type liquid crystal display electrode substrate.

The surface of the electrode substrate for an active matrix type liquid crystal display device obtained by the above-described manufacturing method of the present invention is
It became almost smooth, and as shown in FIG. 11, the alignment film 13 formed on the electrode substrate for the active matrix type liquid crystal display device could also be formed flat. The form of the present invention is
The material used is not limited to the above embodiment,
It goes without saying that various conditions such as the film thickness, the color of the color filter, and the structure of the TFT can be changed.

[0033]

According to the present invention, since the color filter is transferred and formed on the TFT forming electrode substrate from the transfer sheet prepared in advance, the problems that have occurred in the conventional method, namely,
When each color of the colored layer 3 is sequentially formed directly on the TFT forming electrode substrate, it is possible to prevent a problem that a defective color filter is formed and the yield of the TFT substrate is lowered. Also,
It can be said that the method of collectively forming the color filters on the TFT-forming electrode substrate by the transfer sheet requires fewer steps than the conventional method and can improve the production efficiency.

The electrode substrate for an active matrix type liquid crystal display device manufactured according to the present invention has a substantially smooth surface between the light shielding film surface and the pixel electrode surface. The orientation film surface formed above can be flattened. Therefore, when the active matrix type liquid crystal display device is constructed using the electrode substrate for the active matrix type liquid crystal display device manufactured by the present invention, the rubbing treatment for uniformly aligning the liquid crystal molecules is surely performed. It is possible to obtain a liquid crystal display device with good display quality, which can prevent the alignment failure of the above. Then
In the present invention, the light-shielding film is formed directly on the TFT-formed electrode substrate, and as in the conventional case, in consideration of a deviation or the like that occurs when the separately manufactured electrode substrates are opposed to each other and overlapped,
It can be said that there is no need to unnecessarily increase the size of the light shielding film region. Therefore, it can be said that the light-shielding film region may be formed only in the minimum necessary region, and the aperture ratio (display area) of the pixel can be increased, and a bright and high-contrast liquid crystal display device can be obtained. It can be said that it is superior.

[0035]

[Brief description of drawings]

FIG. 1 is a sectional explanatory view showing an embodiment of a transfer sheet used in the present invention.

FIG. 2 is an explanatory view showing an embodiment of a method of manufacturing an electrode substrate for a liquid crystal display device of the present invention in the order of steps.

FIG. 3 is an explanatory view showing one embodiment of a method for manufacturing an electrode substrate for a liquid crystal display device of the present invention in the order of steps.

FIG. 4 is an explanatory view showing one embodiment of a method for manufacturing an electrode substrate for a liquid crystal display device of the present invention in the order of steps.

FIG. 5 is an explanatory view showing one embodiment of a method for manufacturing an electrode substrate for a liquid crystal display device of the present invention in the order of steps.

FIG. 6 is an explanatory view showing one embodiment of a method for manufacturing an electrode substrate for a liquid crystal display device of the present invention in the order of steps.

FIG. 7 is an explanatory view showing one embodiment of a method for manufacturing an electrode substrate for a liquid crystal display device of the present invention in the order of steps.

FIG. 8 is an explanatory view showing one embodiment of a method for manufacturing an electrode substrate for a liquid crystal display device of the present invention in the order of steps.

FIG. 9 is an explanatory view showing one embodiment of a method for manufacturing an electrode substrate for a liquid crystal display device of the present invention in the order of steps.

FIG. 10 is a partially enlarged plan view showing an example of the overlap between the drain electrode and the colored layer in the present invention.

FIG. 11 is an explanatory cross-sectional view showing a configuration example of a liquid crystal display device using the electrode substrate for a liquid crystal display device manufactured according to the present invention.

FIG. 12 is an explanatory cross-sectional view showing a configuration example of a conventional liquid crystal display device.

FIG. 13 is a cross-sectional explanatory view showing an example of superposition of a transfer sheet and a TFT forming electrode substrate.

[Explanation of symbols]

 1 Support Sheet 2 Release Layer 3 Colored Layer 4 Source Electrode 5 Drain Electrode 6 Gate Electrode 7 Opening 8 Transparent Substrate 9 Adhesive Layer 10 Counter Electrode 11 Light-shielding Film 12 Pixel Electrode 13 Alignment Film 14 Protective Film 15 TFT 16 TFT Forming Electrode Substrate 17 Notch 18 Transfer sheet 19 Liquid crystal 20 Liquid crystal display device 21 Adhesive 22 Roll press

Claims (3)

[Claims] 1. An element comprising at least a thin film transistor on a transparent substrate, and a thin film transistor forming electrode substrate on which wirings are formed, on a thin film transistor forming surface side,
A non-heated UV-curable adhesive that is transparent at the time of curing is applied, and a transfer sheet having a color filter formed on a support sheet with a notch that partially exposes the drain electrode of the thin film transistor on a support sheet, The color filter and the thin film transistor forming surface are made to face each other and bonded together, and then ultraviolet rays are irradiated from the thin film transistor non-forming surface side of the electrode substrate, and the adhesive on the light transmitting portion of the electrode substrate is photocured. , A color filter is transferred and formed on the electrode substrate by peeling the supporting sheet, and the unexposed and uncured adhesive on the element and the wiring is removed, and then a transparent conductive film is formed on the entire thin film transistor formation surface side of the electrode substrate. After forming the pattern, this is patterned into a predetermined shape, and the drain electrode portion exposed from the cutout portion of the color filter and the electrode are exposed. Electrically connected, a pixel electrode made of a transparent conductive film is formed, a light-shielding film covering at least the thin film transistor region and the wiring region is formed in a desired shape, and a protective film is formed on the thin film transistor forming surface side of the thin film transistor forming electrode substrate. A method of manufacturing an electrode substrate for an active matrix type liquid crystal display device, which comprises the steps 1 to 3 of forming. 2. The method of manufacturing an electrode substrate for an active matrix type liquid crystal display device according to claim 1, wherein the light shielding film is formed of a non-conductive resin containing a pigment. 3. A transparent substrate having an electrode substrate for an active matrix type liquid crystal display device manufactured by the manufacturing method according to claim 1 or 2, and a counter electrode facing the electrode substrate and having a counter electrode made of a transparent conductive film on the surface thereof. An active matrix liquid crystal display device comprising at least an electrode substrate and a liquid crystal filled and sealed between the two substrates.