JP3708593B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device, and more particularly to transfer between upper and lower substrates.
[0002]
[Prior art]
In the liquid crystal display device, liquid crystal is sealed between two upper and lower electrode substrates, and a voltage is applied between the electrodes on the upper and lower substrates to control the movement of the liquid crystal and perform display. In order to apply a voltage to the electrodes on the upper and lower substrates, a power source is conventionally connected to only one substrate, and silver paste or the like is placed around the screen with a dispenser as a transfer to apply a voltage to the other substrate. The two substrates are electrically connected by this transfer.
[0003]
[Problems to be solved by the invention]
However, in the transfer formation process described above, equipment and labor costs are very expensive. Further, it is necessary to form a place for arranging the transfer in the periphery of the screen including a margin in the transfer forming process in a non-display area around the liquid crystal cell with a certain area (about 1 mm 2 or more). The display area could not be reduced. In addition, impurities mixed when the transfer material is filled in a dispenser or the like may contaminate the liquid crystal material or the alignment film, resulting in a display failure, which causes a decrease in yield. In view of the above problems, an object of the present invention is to provide a liquid crystal display device with high yield, low cost, and good display performance.
[0004]
[Means for Solving the Problems]
According to the configuration and the manufacturing method of the present invention, the step of forming a conventional transfer is performed by covering a columnar spacer formed on a substrate with an electrode, which is in contact with the extraction electrode, and further responsible for transfer between the upper and lower substrates. Can be omitted. Conventionally, it is possible to prevent display defects due to contamination of the liquid crystal material and the alignment film due to impurities mixed when the transfer material is filled in the dispenser, and the yield can be improved.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of a liquid crystal display device according to the present embodiment. A thin film transistor (TFT) array substrate 1 as a lower substrate and a counter substrate 2 as an upper substrate are arranged in parallel to form a liquid crystal 3. It is sandwiched and sealed with a sealing material 4.
[0006]
First, the array substrate 1 has a TFT 6 formed as a switching element on a glass substrate 5 having a thickness of 1.1 mm, and a pixel electrode 7 is connected to the TFT 6. An alignment film 8 is formed as the uppermost layer. In addition, an extraction electrode 9 for supplying power to the counter substrate 2 is formed on the array substrate 1.
[0007]
Next, the counter substrate 2 is formed on a glass substrate 10 having a thickness of 1.1 mm and colored layers 12 (R) and 12 (G) of three colors R, G, and B in the gap between the black light shielding layer 11 and the light shielding layer 11. , 12 (B) are formed. Further, columnar spacers 13 are formed on the counter substrate 2 inside and outside the display area (area surrounded by the sealing material). The columnar spacers 13 are formed on the light shielding layer 11, and the predetermined columnar spacers 13 serve as a transfer between the upper and lower substrates. There are about 10 to 15 columnar spacers responsible for this transfer on all substrates. Further, a common electrode 14 is formed on the entire surface of the counter substrate 2, and an alignment film 15 is formed on the uppermost layer in the display area. Further, the top of the columnar spacer 13 serving as a transfer is in electrical contact with the extraction electrode 9 of the array substrate 1 with the common electrode 14 exposed.
[0008]
The first substrate of the present invention corresponds to the counter substrate 2 in this embodiment. Similarly, the second substrate is the array substrate 1, the first transparent electrode is the common electrode 14, and the second transparent electrode is the pixel. The third electrode corresponds to the electrode 7, and the third electrode corresponds to the common electrode 14.
[0009]
Next, the manufacturing process of the liquid crystal display device of the present embodiment will be described.
First, the manufacturing process of the counter substrate 2 will be described. A photosensitive black resin is applied onto a glass substrate 10 having a thickness of 1.1 mm using a spinner or the like, dried at about 90 ° C. for 10 minutes, and then exposed using a photomask having a predetermined pattern shape. Development is performed with an alkaline solution and baking is performed at 200 ° C. for 60 minutes to form the light-shielding layer 11 having a thickness of about 2.0 μm.
[0010]
Next, an ultraviolet curable acrylic resin in which a red pigment is dispersed is applied with a spinner, and ultraviolet rays are irradiated through a photomask that irradiates the portion to be colored red with ultraviolet rays, for example, 1% of KOH. Development is performed with an aqueous solution for about 10 seconds to form a red colored layer 12 (R). Similarly, green and blue colored layers 12 (G) and 12 (B) are repeatedly formed and fired at 230 ° C. for 60 minutes, respectively. At this time, the film thicknesses of the red, green, and blue colored layers 12 (R), 12 (G), and 12 (B) were 1.5 μm, respectively.
[0011]
Next, an ultraviolet curable acrylic resin containing no pigment is applied to the entire surface with a spinner, and 100 mJ / cm ² of ultraviolet light is applied at a wavelength of 365 nm through a photomask that forms columnar spacers 13 at predetermined positions. Irradiate and develop with a 1% aqueous solution of KOH for 30 seconds to form columnar spacers 13 having a height of about 4 μm. According to such a forming method, the columnar spacer 13 can be formed in a tapered shape. At this time, the columnar spacers 13 formed in the display area are formed on the light shielding layer 11. At this time, the columnar spacer 13 becomes an obstacle in the subsequent rubbing process, and an area behind the rubbing is formed. Therefore, it is necessary to consider the arrangement of the columnar spacers 13 so that the shaded portion is settled in the region of the light shielding layer 11 and is positioned so as not to affect the display.
[0012]
In addition, the one that bears the transfer is formed at a position that comes into contact with the extraction electrode 9 when combined with the array substrate 1.
The columnar spacers 13 may be formed simultaneously using the colored layers 12 (R), 12 (G), and 12 (B). A photomask for forming the colored layers 12 (R), 12 (G), and 12 (B) having a pattern that can simultaneously form the columnar spacers 13 is used. Of course, a plurality of colored layers may be stacked depending on the thickness. If the columnar spacers 13 are formed simultaneously with the colored layer 12 in this way, the number of steps for forming the spacers can be reduced by one.
[0013]
Further, the columnar spacer 13 serving as a transfer may be formed in the display area as shown in FIG. 1 or may be formed outside the display area.
Thereafter, an ITO (Indium Tin Oxide) film is formed as the common electrode 14 to a thickness of 1500 angstrom by sputtering. Here, since the columnar spacers 13 are formed in a tapered shape, the ITO film can be uniformly coated on the columnar spacers 13.
[0014]
On this, for example, polyimide is formed and a rubbing process is performed to form an alignment film 15, thereby completing the counter substrate 2.
Next, in the manufacturing method of the array substrate 1, film formation and patterning are repeated in the same manner as the step of forming the normal TFT 6 on the glass substrate 5 having a thickness of 1.1 mm. A gate line 20 made of MoW (molybdenum / tungsten) or MoTa (molybdenum / tantalum), an unillustrated auxiliary capacitance line, and a transfer lead electrode 9 integral with the auxiliary capacitance line are formed, and SiO _x is formed on the entire surface. A gate insulating film 21 is formed by plasma CVD to a thickness of 4000 angstroms.
[0015]
On top of this, a semiconductor layer 22 made of a-Si (amorphous silicon) is formed by plasma CVD and patterned into a predetermined shape.
Further, an electrode made of Mo / Al / Mo is formed through an n ⁺ a-Si ohmic contact layer, and patterned into a desired shape to form a source electrode 23, a drain electrode 24, and a signal line (not shown).
[0016]
Next, the pixel electrode 7 is formed by patterning ITO, which is a transparent electrode, in contact with the source electrode 23. Finally, polyimide or the like is formed and the alignment film 8 is formed by performing a rubbing process. However, the region in contact with the columnar spacer 13 that bears the transfer on the counter substrate 2 side does not cover the alignment film 8, and the extraction electrode 9 To expose. On the extraction electrode 9, as shown in FIG. 1, the same material as the electrode such as Mo / Al / Mo may be formed. This has the advantage that the height can be adjusted.
[0017]
Thereafter, the sealing material 4 is printed along the periphery of the alignment film 15 of the counter substrate 2 except for the injection port.
Next, the array substrate 1 and the alignment film 8 of the counter substrate 2 are opposed to each other and arranged so that the rubbing direction forms an angle of 90 °, and the sealing material 4 is cured and bonded by heating.
[0018]
Next, the liquid crystal 3 can be injected by placing an empty cell in a vacuum and gradually returning the state from the vacuum state to the atmospheric pressure with the liquid crystal material immersed in the injection port.
In this way, the desired liquid crystal display device in this embodiment can be obtained.
[0019]
According to the configuration and the manufacturing method of the present embodiment, the step of forming the transfer between the upper and lower substrates can be eliminated.
Although this embodiment has a structure in which a light shielding layer is formed on the counter substrate side, the present invention can also be applied to a liquid crystal display device having a structure in which a light shielding layer is formed on the array substrate side. In this case, the substrate on which the columnar spacer is formed and the substrate on which the light shielding layer is formed are separated.
[0020]
In addition, this embodiment is an active matrix type liquid crystal display device using a TFT array substrate, but the structure of the TFT is not limited to the reverse stagger type as in this embodiment. The present invention is also applicable to a simple matrix type liquid crystal display device having the above electrodes.
As described above, it is needless to say that the present embodiment can add many changes and modifications.
[0021]
【The invention's effect】
According to the present invention, a transparent electrode is coated on a columnar spacer, and the predetermined columnar spacer also serves as a transfer between the upper and lower substrates, whereby the transfer forming step can be omitted. That is, a significant cost reduction such as equipment and labor costs in the transfer forming process is eliminated, and impurities are not mixed at the time of work in the conventional transfer forming process, so that poor yield due to display defects can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a columnar spacer that bears a transfer, which is a liquid crystal display device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a columnar spacer that does not bear transfer in one embodiment of the present invention.
FIG. 3 is a view showing a columnar spacer which is a columnar spacer responsible for transfer in one embodiment of the present invention and is formed by laminating a plurality of colored layers.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Array substrate 2 ... Opposite substrate 3 ... Liquid crystal 4 ... Sealing material 6 ... TFT
7 ... Pixel electrodes 8, 15 ... Alignment film 9 ... Lead electrode 11 ... Light shielding layer 12 ... Colored layer 13 ... Columnar spacer 14 ... Common electrode

Claims (6)

Liquid crystal is sandwiched between the first substrate and the second substrate,
The first substrate includes a plurality of columnar spacers that maintain a distance between the first substrate and the second substrate, and a first transparent electrode that applies a voltage to the liquid crystal,
In the liquid crystal display device, the second substrate includes a second transparent electrode that applies a voltage to the liquid crystal, and an extraction electrode that supplies power from a power source.
The plurality of columnar spacers are covered with a columnar spacer covered with an alignment film, and a third electrode disposed opposite to the extraction electrode and the same, integral or electrically connected with the first transparent electrode. A liquid crystal display device comprising a columnar spacer, wherein the lead electrode, the third electrode, and the first transparent electrode are electrically connected. The liquid crystal display device according to claim 1, wherein the columnar spacer is characterized by comprising a resin layer. Wherein the first substrate and the colored layer of a plurality of colors are formed, the liquid crystal display device according to claim 1 or 2, wherein the columnar spacer is characterized in that the colored layer is formed by stacking a plurality. The columnar spacer, the liquid crystal display device according to any one of claims 1 to features that tapered 3. A liquid crystal is sandwiched between a first substrate and a second substrate, the first substrate includes a plurality of columnar spacers that maintain a distance between the first substrate and the second substrate, and a voltage applied to the liquid crystal. And a second transparent electrode for applying a voltage to the liquid crystal and a lead electrode for supplying electric power from a power source. Because
The manufacturing process of the first substrate includes:
Forming a light shielding film;
Forming a colored layer;
A step of forming a columnar spacer that bears the transfer and a columnar spacer that does not bear the transfer;
And forming the first transparent electrode comprises at least the upper two columnar spacers,
Forming an alignment film excluding the columnar spacer responsible for the transfer ; and
Method of manufacturing a liquid crystal display device according to feature in that it comprises a step of connecting the lead electrode and the first transparent electrode through a columnar spacer responsible for the transfer. A liquid crystal is sandwiched between a first substrate and a second substrate, the first substrate includes a plurality of columnar spacers that maintain a distance between the first substrate and the second substrate, and a voltage applied to the liquid crystal. And a second transparent electrode for applying a voltage to the liquid crystal and a lead electrode for supplying electric power from a power source. Because
The manufacturing process of the first substrate includes:
Forming a light shielding film;
Forming a columnar spacer that bears the same material as the colored layer and at the same time, and a columnar spacer that does not bear the transfer;
And forming the first transparent electrode comprises at least the upper two columnar spacers,
Forming an alignment film excluding the columnar spacer responsible for the transfer ; and
Method of manufacturing a liquid crystal display device according to feature in that it comprises a step of connecting the lead electrode and the first transparent electrode through a columnar spacer responsible for the transfer.

Images