JP2002072187A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability in relation to a displaying characteristic by preventing the lack of uniform display from occurring. SOLUTION: A secondary shading layer 12 is placed in a clearance between wires 13 in the section where a black resist frame area 11 is located in a TFT array substrate 2 forming electrode wiring with a thin-film transistor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly to providing a liquid crystal display having high display performance and high reliability.

[0002]

2. Description of the Related Art A liquid crystal display device generally used at present has a liquid crystal composition sandwiched between two glass substrates having electrodes. The structure is fixed with an adhesive and the liquid crystal sealing port is sealed with a sealant. As spacers for keeping the distance between the two substrates constant, plastic beads or the like having a uniform particle size are scattered between the substrates. Among them, in the liquid crystal display device for color display, a color filter having an RGB coloring layer is formed on one of two glass substrates.

[0003] These liquid crystal display devices generally have a structure in which a light shielding layer is provided in a frame portion. A light-shielding layer is often provided on a color filter substrate, but by providing both a color filter and a light-shielding layer on an active matrix substrate, it is possible to increase the aperture ratio of a pixel portion, and a liquid crystal display device with a high transmittance is provided. Have been proposed. In this configuration, a configuration has been proposed in which a black resist is processed using photolithography to form a light-shielding layer.

[0004]

However, as described above, when a light-shielding layer made of a black resist is provided on a frame portion in a liquid crystal display device, light during exposure does not reach a deep portion, and the black resist has a light reaction. The unreacted substances are unevenly distributed near the interface between the black resist and the substrate, and when these are irradiated with backlight from the back surface of the liquid crystal display device, the unreacted substances are decomposed and the liquid crystal layer is decomposed. To cause display unevenness.

Accordingly, an object of the present invention is to provide a liquid crystal display device in which display unevenness is prevented and the reliability of display performance is improved.

[0006]

A liquid crystal display device according to the present invention comprises a pair of substrates, a liquid crystal composition disposed between the pair of substrates, and a frame formed on at least one of the pair of substrates. A first light-shielding layer made of a photosensitive resist that shields light, wiring formed between the first light-shielding layer and the one of the substrates, and connected to a display area inside the frame portion, And a second light-blocking layer formed between the one substrate and different from the wiring.

[0007]

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

FIG. 1 shows a schematic sectional configuration of an active matrix liquid crystal display device according to a first embodiment of the liquid crystal display device of the present invention.

Active matrix liquid crystal display device 20
Is provided with an active matrix substrate 2 provided with a coloring layer as a color filter, and a counter substrate 9 which is opposed to the active matrix substrate 2 by a spacer 7 with a predetermined gap therebetween. The liquid crystal composition 10 is sandwiched between the liquid crystal composition 10 and the counter substrate 9. The active matrix substrate 2 and the opposing substrate 9 are bonded with an adhesive 8. On the active matrix substrate 2, red, green, and blue colored layers 3, 4, and 5 are formed.
Are formed.

As will be described later in detail, as a first embodiment, the black resist frame 11 and the active matrix substrate 2
The second frame light-shielding layer 12 is formed between the first and second frames. The second frame light-shielding layer has a floating potential or a ground potential, not for the purpose of supplying current to the display area. Reference numeral 13 denotes a wiring made of Al. The wiring 13 is connected for the purpose of supplying a current from the frame to the display area inside. The active matrix liquid crystal display device 20 is, for example, a thin film transistor 1
And 100 pixels vertically and horizontally with electrode wiring formed, total 10,000
It has a pixel, and the number of components of the thin film transistor 1, the coloring layers 3, 4, and 5 shown in FIG. 1 is different from the actual number.

Here, the outline of the present invention will be described.

FIG. 2A shows a state in which a black resist frame portion 11 as a light shielding layer is formed on the frame portion on the substrate 50 by photolithography. An unreacted substance 52 such as a photoreaction initiator remains in a deep part where the exposure does not reach in the black resist frame part 11. Note that the drawing is a part of the liquid crystal display device, 53 is an alignment film, and 54 is a liquid crystal composition.

As shown in FIG. 2B, when light from a backlight (not shown) is applied to the black resist frame 11 from the lower surface of the substrate 50, the remaining unreacted substances undergo photolysis. Decomposition products 55 are generated.

As shown in FIG. 2C, these decomposed products 55 are eluted in the liquid crystal composition 54 to cause display unevenness.

Therefore, as shown in FIG. 2D, a second frame light-shielding layer 12 is provided between the wirings below the black resist frame 11.
Is provided. Reference numeral 13 denotes a wiring made of Al.

Alternatively, as shown in FIG. 2E, a colored layer 58 is provided below the black resist frame 11.

As a result, it is possible to greatly reduce the photolysis of the remaining unreacted substance, and to obtain a liquid crystal display device having no display unevenness even when a reliability test is performed.

FIG. 3 shows the opening ratio of the frame portion and the occurrence rate of defects.

According to an experiment, when the aperture ratio of the wiring 13 and the second frame light-shielding layer 12 exceeds 30%, display unevenness starts to occur. In the case where the second frame light-shielding layer disposed between the wirings is the same layer as the wiring, if the aperture ratio is less than 5%, an operation failure starts due to a short circuit between the wiring and the second frame light-shielding layer. When a colored layer is provided under a black resist, it is effective to provide a layer for cutting a light wavelength that decomposes the remaining unreacted substances.

Next, the configuration of the liquid crystal display device 20 of the first embodiment and a method of manufacturing the same will be described with reference to FIG. 1 and FIGS.

First, as shown in FIG. 4, film formation and patterning are repeated in the same manner as in a process for forming a normal TFT, and the vertical and horizontal directions in which the thin film transistor 1 and electrode wiring are formed are formed.
The TFT array substrate 2 having 0 pixels and 10,000 pixels in total is formed. At this time, the second frame light-shielding layer 12 is also formed of Al in the gap of the wiring 13 made of Al at the portion where the black resist frame 11 to be described later is arranged. The present embodiment is characterized in that the second frame light shielding layer 12 is formed as described above. At this time, the aperture ratio of the wiring 13 in the frame portion and the second frame light shielding layer 12 is 30%.

Subsequently, as shown in FIG. 5, an ultraviolet-curable acrylic resin resist in which a red pigment is dispersed is applied over the entire surface by a spinner, and a photomask is applied to irradiate a portion to be colored red with light. 10 at 365 nm wavelength
Irradiate with 0 mJ / cm ² and develop with a 1% aqueous solution of KOH for 10 seconds to form a red colored layer 3 on that portion. Similarly, a green coloring layer 4 and a blue coloring layer 5 are formed.

Thereafter, as shown in FIG. 6, an ITO film is formed as a transparent electrode 6 by a 150 nm sputtering method, and is patterned by a photolithography method.

Thereafter, as shown in FIG. 7, a photosensitive acrylic transparent resin is applied as a black resist by spinner coating,
After drying at 90 ° C. for 10 minutes, 300 mJ / cm ² at a wavelength of 365 mm using a photomask having a predetermined pattern shape.
And then developed with an aqueous alkaline solution having a pH of 11.5, and baked at 200 ° C. for 60 minutes to obtain a height of 5.5 μm.
spacers 7 as m projections and black resist frame 11
To form The arrangement of the spacers 7 is such that T
A group of spacers 7 having a circular shape with a diameter of 12 μm and having a variation of ± 2 μm is formed at the center of the screen at a place where an overlapping portion with the FT and the pixel electrode is avoided. The density is 1/10 pixels.

Thereafter, as shown in FIG. 8, a 50 nm thick polyisid is applied as an alignment film material, and a rubbing process is performed to form an alignment film 14.

Next, an ITO film is formed as a transparent electrode 15 on the opposing substrate 9 by a sputtering method to a thickness of 150 nm, and an alignment film material similar to the alignment film 14 is formed thereon. A film 16 is formed. Thereafter, an adhesive 8 is printed along the periphery of the alignment film 16 of the counter substrate 9 except for the injection port, and an electrode transfer material for applying a voltage from the active matrix substrate 2 to the counter electrode is formed around the adhesive 8. It is formed on an electrode transfer electrode. Then, the active matrix substrate 2 and the counter substrate 9 on which ITO is formed are arranged so that the alignment films 14 and 16 face each other and the rubbing directions thereof are 90 degrees, and the adhesive 8 is cured by heating and bonded.

Next, the liquid crystal composition 10 is injected from the injection port by a usual method, and thereafter the injection port is sealed with an ultraviolet curable resin.

The thus formed active matrix liquid crystal display device 20 of the color display type shown in FIG. 1 has a very uniform cell gap of 5.1 ± 0.2 μm and an OD of the black resist frame portion 11 of 3%. .5, which is a practically sufficient black level. The active matrix liquid crystal display device 20 is subjected to a high temperature and high humidity (50 ° C., 80%) condition of 100
A continuous lighting test was performed for 0 hours. As a result, no display unevenness occurred and good display quality was secured.

Further, the wiring 13 in the frame portion in the active matrix liquid crystal display device 20 of the first embodiment described above.
And the second frame light-shielding layer 12 together with an aperture ratio 30% of 5
% Of the active matrix liquid crystal display device. When a test similar to that of the first embodiment was performed on this active matrix liquid crystal display device, no display unevenness occurred, and good display quality was secured.

Further, in the active matrix liquid crystal display device 20 of the first embodiment, the above-mentioned aperture ratio of 30% is reduced to 31%.
An active matrix liquid crystal display device was manufactured.
When a test similar to that of the first embodiment was performed on this active matrix liquid crystal display device, extremely minute display unevenness occurred on one of the 00 sheets.

The above-described aperture ratio of 30% in the active matrix liquid crystal display device 20 of the first embodiment is set to 4.9.
% Of the active matrix liquid crystal display device. When a test similar to that of the first embodiment was performed on this active matrix liquid crystal display device, an operation failure occurred due to a short circuit between the second frame light-shielding layer provided between the wirings on one of the 150 substrates and the wiring.

In the present embodiment, the second frame light-shielding layer
Although Al was used, it may be formed of another material, for example, another metal film forming the TFT.

Next, a second embodiment will be described.

FIG. 9 shows a schematic sectional configuration of an active matrix liquid crystal display device according to a second embodiment of the liquid crystal display device of the present invention. The same portions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The active matrix liquid crystal display device 30 of the second embodiment is different from the active matrix liquid crystal display device 20 of the first embodiment in that the green colored layer 17 is replaced with the black resist frame portion 18 instead of the second frame light shielding layer 12. It is formed between the active matrix substrate 2. When a test similar to that of the first embodiment was performed on the active matrix liquid crystal display device 30 of the second embodiment, no display unevenness occurred and good display quality was secured.

The active matrix liquid crystal display device 30 was prepared by providing a red coloring layer instead of the green coloring layer 17. When a test similar to that of the first embodiment was performed on this active matrix liquid crystal display device, no display unevenness occurred, and good display quality was secured.

As described above, according to the embodiment of the present invention, a liquid crystal display device having good display performance and high reliability can be obtained at low cost.

It should be noted that the present invention is not limited to the above embodiments, and various modifications can be made at the stage of implementation without departing from the scope of the invention. In addition, the embodiments may be implemented in appropriate combinations as much as possible, in which case the combined effects can be obtained. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

[0039]

As described in detail above, according to the present invention,
It is possible to provide a liquid crystal display device in which display unevenness is prevented and display performance is improved in reliability.

[Brief description of the drawings]

FIG. 1 is a sectional view of an active matrix liquid crystal display device according to a first embodiment of the liquid crystal display device of the present invention.

FIG. 2 is a diagram for explaining an outline of the present invention.

FIG. 3 is a diagram showing an opening ratio of a frame portion and a defect occurrence rate.

FIG. 4 is a diagram for explaining the configuration of the active matrix liquid crystal display device according to the first embodiment.

FIG. 5 is a diagram for explaining the configuration of the active matrix liquid crystal display device according to the first embodiment.

FIG. 6 is a diagram for explaining the configuration of the active matrix liquid crystal display device according to the first embodiment.

FIG. 7 is a diagram for explaining the configuration of the active matrix liquid crystal display device according to the first embodiment.

FIG. 8 is a diagram for explaining the configuration of the active matrix liquid crystal display device according to the first embodiment.

FIG. 9 is a sectional view of an active matrix liquid crystal display device according to a second embodiment of the liquid crystal display device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thin film transistor 2 ... Active matrix substrate 3 ... Coloring layer (red) 4 ... Coloring layer (green) 5 ... Coloring layer (blue) 6 ... Transparent electrode 7 ... Spacer 8 ... Adhesive 9 ... Counter substrate 10 ... Liquid crystal composition 11 , 18: black resist frame portion 12: second frame light shielding layer 13: wiring 14, 16, alignment film 17: green coloring layer

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) G09F 9/30 349 G09F 9/30 349B (72) Inventor Natsuko Maya 1-9-9 Hararacho, Fukaya City, Saitama Prefecture F-term in Toshiba Fukaya Factory (reference)

Claims (4)

[Claims] A first light-shielding layer formed of a pair of substrates, a liquid crystal composition disposed between the pair of substrates, and a photosensitive resist formed on at least one of the pair of substrates and shielding a frame portion from light. And a wiring formed between the first light-shielding layer and the one substrate and connected to a display area inside the frame portion, and formed between the first light-shielding layer and the one substrate. And a second light-blocking layer different from the wiring. 2. The liquid crystal display device according to claim 1, wherein the second light-shielding layer is formed of the same material as the wiring. 3. The wiring in the frame portion and the second wiring.
2. The liquid crystal display device according to claim 1, wherein the aperture ratio with respect to the light shielding layer is 5 to 30%. 4. The liquid crystal display device according to claim 1, wherein said second light shielding layer is made of a colored resin.