JPH0682784A - Manufacture of liquid crystal panel - Google Patents

Abstract

PURPOSE:To provide a liquid crystal panel in which the orienting state of a liquid crystal is differed every fine area without depending on photolithography in the manufacture of the liquid crystal panel. CONSTITUTION:In a method for manufacturing a liquid crystal panel formed of a liquid crystal inserted between first and second opposed bases, an orienting film 36 provided on the first base, and an orienting film provided on the second base, in which the orienting film 36 of the first base and the orienting film of the second base being oriented so that the orienting state of the liquid crystal is differed every fine area, the first base 22 and the second base are prepared, the orienting films 36 are printed in determined patterns on the first base and the second base, respectively, and the orienting film 36 are rubbed.

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 a liquid crystal panel in which the alignment state of liquid crystal is different for each minute region.

[0002]

2. Description of the Related Art A liquid crystal panel is one in which liquid crystal is inserted between a pair of transparent glass substrates facing each other. A pixel electrode and an alignment film are provided on the inner surface of one glass substrate, and a common electrode and an alignment film are provided on the inner surface of the other substrate. Recently, pixel electrodes are often driven by active matrix driving. Further, a polarizing plate is provided on the outside of each of these substrates.

In the liquid crystal panel, the liquid crystal molecules are aligned and pretilt according to the rubbing directions of the alignment films on both substrates. In a twisted nematic liquid crystal display device in which polarizing plates are arranged orthogonally, the rubbing directions of the alignment films on both substrates are substantially perpendicular to each other, and the liquid crystal molecules spiral from one substrate to the other. Twist. Then, when no voltage is applied to the liquid crystal, the molecules of the liquid crystal maintain the initial twist and pre-tilt, and the incident light travels while swirling along the twist of the liquid crystal and exits from the liquid crystal panel. When a voltage is applied, the liquid crystal rises, the birefringence action of the liquid crystal is weakened, the above-mentioned light swirling action is weakened, and it becomes difficult for the incident light to pass through the liquid crystal panel, so that black display can be obtained. In this way, an image with bright and dark contrast as a whole is formed while controlling the voltage applied to the liquid crystal.

In such a liquid crystal panel, the contrast of light and dark of the image changes depending on the direction in which the viewer looks at the screen. This is generally recognized as a viewing angle characteristic of a liquid crystal panel. For example, when viewing a liquid crystal panel that has undergone a certain orientation treatment from diagonally above, a slight increase in voltage causes a large decrease in transmittance, and the increase in voltage causes the transmittance to increase again. When the panel is viewed obliquely from below, the transmittance does not decrease easily even if the voltage is increased, and even if an attempt is made to obtain a black display, the display becomes relatively bright.

In order to solve the influence of such a viewing angle characteristic, Japanese Patent Laid-Open No. 63-106624 proposes to form two regions having different alignment directions of liquid crystal molecules in one pixel. . According to these proposals, the viewing angle characteristics as a whole can be improved by mixing the viewing angle characteristics in the obliquely upward direction and the viewing angle characteristics in the obliquely downward direction.

FIG. 5 is a diagram showing the alignment treatment of such a conventional liquid crystal panel. FIG. 5 shows an area for one pixel, for example, and one pixel is divided into two regions A and B in which the alignment state of liquid crystal molecules is different. Light enters one of the substrates (herein, the substrate on the light incident side is called the lower substrate), passes through the liquid crystal, and exits from the other substrate (the upper substrate). Referring to FIG. 4, the rubbing direction of the alignment film on the lower substrate is indicated by an arrow R _L , and the rubbing direction of the alignment film on the upper substrate is indicated by an arrow R _U.

In the region A of FIG. 5, the rubbing direction R _L of the alignment film on the lower substrate is 45 ° to the left and the rubbing direction R _U of the alignment film on the upper substrate is 45 ° to the left. As described above, the viewing angle characteristics in the case of such an alignment treatment are such that, when the liquid crystal panel is viewed obliquely from above, the transmittance decreases significantly when a slight voltage is applied, and the transmittance increases again as the voltage increases. become. This viewing angle characteristic is indicated by a double arrow. On the other hand, in the region B, the rubbing direction R _L of the alignment film on the lower substrate is 45 ° to the right and the rubbing direction R _U of the alignment film on the upper substrate is 45 ° to the right. The viewing angle characteristics in the case of such an alignment process are upside down from those in the region A.

[0008] Such a minute region A with different orientation treatment
And the minute area B are arranged side by side, the viewing angle characteristic with high transmittance and the viewing angle characteristic with low transmittance are added, and the viewing angle characteristic is as if divided by 2. The viewing angle characteristics are approached, and the viewing angle characteristics as a whole are improved.

For such an alignment treatment, in FIG. 5, for example, with respect to the alignment film on the lower substrate shown by a broken line, rubbing is performed in the upward direction to the left in the minute region A.
In the minute area B, it is necessary to perform rubbing in the downward right direction. That is, it is necessary to perform rubbing in the opposite directions on the same substrate for each of the minute regions A and B.

However, it is not easy to perform such rubbing for each of the minute areas A and B corresponding to one pixel. FIG. 7 shows an example of a conventional method of rubbing using a resist as a mask. In FIG. 7, the alignment film has a two-layer structure. As shown in (A), a substrate 1 on which a pixel electrode 2 is formed is prepared, a first alignment material layer (referred to as a lower alignment material layer) 3 is applied on the substrate 1, and a lower alignment layer is formed. A second alignment material layer (referred to as an upper alignment material layer) 4 is applied onto the alignment material layer 3. Arrow X on the orientation material layer 4 on the upper side
Rub in the direction indicated by.

Next, as shown in (B), a resist 5 is applied on the upper alignment material layer 4 and the upper alignment material layer 4 is etched. In (B), the resist 5 has already been exposed and developed to have a predetermined shape (a size corresponding to the minute regions A and B), and the upper alignment material layer 4 is etched using the resist 5 as a mask. ing. Therefore, the lower orientation material layer 3 is exposed through the openings of the resist 5 and the upper orientation material layer 4. Therefore, as shown in (C), when rubbing is performed from above the resist 5 in the direction of the arrow Y, only the exposed portion of the lower orientation material layer 3 is rubbed. Then, as shown in (D), when the resist 5 is peeled off, the first rubbing X remains on the upper alignment material layer 4 covered with the resist 5, and thus rubbing in the opposite direction is achieved. It

FIG. 8 shows another example of a conventional method of rubbing using a resist as a mask. Also in FIG. 8, the alignment film has a two-layer structure. As shown in (A), the pixel electrode 2
The lower orientation material layer 3 and the upper orientation material layer 4 are applied onto the substrate 1 on which the layers have been formed. In this method, rubbing is not performed here. Next, as shown in (B), a resist 5 is applied on the upper-layer-side orientation material layer 4, and the upper-layer-side orientation material layer 4 is etched. The resist 5 has already been exposed and developed to have a predetermined shape (size corresponding to the minute regions A and B), and the upper alignment material layer 4 is patterned into a predetermined shape. Therefore, as shown in (C), the resist 5 is peeled off, and rubbing is performed in the direction of the arrow Y from above the exposed upper layer side alignment material layer 4 and lower layer side alignment material layer 3. Therefore, the exposed upper orientation material layer 4 and the exposed lower orientation material layer 3 are rubbed in the same direction. When such a substrate 1 is assembled as a liquid crystal panel, when the resist 5 is peeled off from the upper alignment material layer 4 and the lower alignment material layer 3, fine regions A and B having different liquid crystal alignment states are formed. . The details will be described later along with the description of the invention of the present application.

[0013]

In order to form the minute regions A and B having different alignment states of liquid crystal, it was conventionally necessary to pattern the alignment film by photolithography and rub it. However, patterning by photolithography has a problem that many steps such as resist coating, pre-cure, exposure, development, post-cure, etching, and resist stripping are required. Further, as the type of the alignment film, only the alignment film having sufficient resistance to the chemicals used in photolithography can be used, which causes a big limitation.

An object of the present invention is to provide a method of manufacturing a liquid crystal panel which can obtain a liquid crystal panel in which the alignment state of liquid crystal is different for each minute region without using photolithography.

[0015]

A method of manufacturing a liquid crystal panel according to the present invention comprises a first and a second opposed substrates 22 and 24.
The liquid crystal 26 inserted between the two, the alignment film 36 provided on the first substrate, and the alignment film 32 provided on the second substrate.
A method of manufacturing a liquid crystal panel, wherein the alignment film 36 of the first substrate and the alignment film 32 of the second substrate are subjected to an alignment treatment so that the alignment state of the liquid crystal is different for each minute region. , The first substrate 22 and the second substrate 24 are prepared, and the alignment film 3 is formed on each of the first substrate and the second substrate.
6 and 32 are printed in a predetermined pattern, and the alignment films 36 and 3
2 is rubbed. Also,
The first substrate 22 and the second substrate 24 are prepared, and a photosensitive alignment material that will be the alignment films 36 and 32 is applied to each of the first substrate and the second substrate, and the alignment is performed. The material material is exposed through a mask having a predetermined pattern to remove the exposed or unexposed portion of the alignment material, and the alignment film is rubbed. 1 substrate 22 and the second substrate 24 are prepared,
Alignment films 36 and 3 are formed on the first substrate and the second substrate, respectively.
It is also possible to employ a method for producing a liquid crystal panel, which comprises applying an alignment material material of No. 2 in a thin line shape according to a predetermined pattern and rubbing the alignment film.

[0016]

In the above structure, the alignment state of the liquid crystal is different for each minute region. Then, according to the above manufacturing method, a pattern corresponding to a minute region of the alignment film can be formed without using photolithography, the process is facilitated, and the cost can be reduced.

[0017]

FIG. 2 shows a liquid crystal panel 2 according to the first embodiment of the present invention.
Polarizing plates (not shown) are arranged on both sides of the liquid crystal panel 20 in a vertical relationship in the normally white mode or in a parallel relationship in the normally black mode. The liquid crystal panel 20 has a liquid crystal 26 sealed between a pair of transparent glass substrates 22 and 24. The liquid crystal 26 is a twisted nematic liquid crystal. Light from a light source (not shown) enters the liquid crystal panel 20 from the direction of arrow L, for example, and the viewer views the liquid crystal panel 20 from the direction opposite to the incident direction. Substrate 22 will be referred to as a lower substrate, and the viewer-side substrate 24 will be referred to as an upper substrate.

The color filter layer 2 is formed on the inner surface of the upper substrate 24.
8. The ITO common electrode 30 is provided, and the alignment film 32 is provided on the common electrode 30. A pixel electrode 34 and an alignment film 36 are provided on the inner surface of the lower substrate 22. The pixel electrode 34 provided on the lower substrate 22 is connected to the active matrix circuit. As shown in FIG. 3, the active matrix circuit includes a drain bus line 38 and a gate bus line 40 extending vertically and horizontally in a matrix, and the pixel electrode 34 includes a drain bus line 38 and a gate via a thin film transistor (TFT) 42. It is connected to the bus line 40.

As shown in FIG. 4, the thin film transistor 42 comprises a semiconductor layer 44, a gate electrode 40a, a drain electrode 38a, and a source electrode 46. The source electrode 46 is connected to the pixel electrode 34, and the drain electrode 38a
Is connected to the drain bus line 38, and the gate electrode 40
a is connected to the gate bus line 40. The gate insulating layer 48 is provided between the gate electrode 40a and the semiconductor layer 44.

As shown in FIGS. 2 and 3, in order to improve the viewing angle characteristics as described above, the alignment film 32 and the alignment film 36 are formed in the minute regions A having different alignment states of the liquid crystal 26.
Oriented so as to form B. The alignment film 36 on the lower substrate 22 side has a two-layer structure including an alignment material layer 50 on the lower layer side and an alignment material layer 52 on the upper layer side, and the alignment film 32 on the upper substrate 24 side also the alignment material layer 54 on the lower layer side. And the upper alignment film 56 has a two-layer structure.

The upper orientation material layers 52, 56 are patterned to be minute portions corresponding to the minute regions A, B, and the orientation material layers 50, 56 on the lower layer side from the openings adjacent to the respective minute portions. 54 is exposed. Alignment material layers 52 and 54 on the upper layer side that are minute portions are alternately provided on the upper substrate 22 side and the lower substrate 24 side. That is, in the minute region A, the upper alignment material layer 52 on the lower substrate 22 side faces the upper alignment material layer 54 on the upper substrate 24 side, and in the small region B, the upper substrate 24. The upper alignment material layer 56 on the lower side is opposed to the lower alignment material layer 50 on the lower substrate 22 side.

The alignment films 32 and 36 are manufactured by the procedure shown in FIG. Although FIG. 1 shows only the alignment film 36, the same applies to the alignment film 32. In FIG. 1, as shown in (A),
First, the lower substrate 22 (upper substrate 24) is prepared. Lower substrate 22
Is provided with a pixel electrode 34 and an active matrix. In this embodiment in which the alignment film 36 has a two-layer structure, the lower alignment material layer 50 is applied to the lower substrate 22. Next, the alignment material layer 52 on the upper side of the alignment film 36 is printed on the lower substrate 22 in a predetermined pattern. The printing process is (B)
As shown in FIG. 5, the plate 100 having a predetermined pattern corresponding to the minute areas A and B is used, and the ink of the ink board 102 (the material solution of the alignment material layer 52 on the upper layer side) is applied to the plate 100.
The ink 104 is printed on the lower substrate 22 by applying 104 and pressing the plate 100 against the lower substrate 22 as shown in FIG. That is, as shown in (D), the upper alignment material layer 52 is printed on the lower alignment material layer 50 of the lower substrate 22. Then, the alignment film 36 is rubbed by the rubbing roller 106. Then, rubbing is performed in a certain direction on the portion of the alignment material layer 52 on the upper layer side and the portion of the lower alignment layer 50 exposed from the predetermined pattern.

The lower orientation material layers 50 and 54 are made of, for example, Si.
It is made of an inorganic alignment material such as O ₂ or TiO ₂ , and the upper alignment material layers 52 and 56 are made of an organic alignment material such as polyimide having an imidization ratio of 100%. By changing the alignment material in this way, a difference in pretilt of the liquid crystal can be produced when the same rubbing is performed, and the pretilt of the liquid crystal in contact with the alignment material layers 52 and 56 on the upper layer side is the alignment material layer 50 on the lower layer side. It becomes larger than the pretilt of the liquid crystal in contact with 54.

As shown in FIG. 2, when the upper surface side alignment material layers 52 and 56 are patterned and a certain amount of rubbing is performed on the entire surface, the upper layer of the alignment film 32 of the upper substrate 24 is formed in a minute area A. The liquid crystal molecules near the side alignment material layer 56 have a pretilt α ₁ , and the liquid crystal molecules near the alignment layer 50 below the alignment film 36 of the lower substrate 24 have a pretilt α ₂ . On the contrary, in the area B adjacent to the area A,
The liquid crystal molecules near the alignment material layer 54 below the alignment film 32 of the upper substrate 24 have a pretilt α ₂ , and the liquid crystal molecules near the alignment material layer 52 above the alignment film 36 of the lower substrate 22 have a pretilt α _1. It is supposed to be. Where α ₁ > α ₂
Have a relationship.

FIG. 6 is a diagram simply showing this alignment treatment. In the minute area A, the alignment film 32 of the upper substrate 24 is formed.
The rubbing direction is indicated by arrow R _U , and the rubbing direction of the alignment film 36 on the lower substrate 22 is indicated by arrow R _L. In the minute region A, the molecules of the liquid crystal near the alignment film 32 of the upper substrate 24 pretilt at a large angle α ₁ , and the molecules of the liquid crystal near the alignment film 32 of the lower substrate 22 facing the small angle α ₂ are small. To pretilt. In the minute region B, the liquid crystal molecules near the alignment film 36 of the lower substrate 22 pretilt at a large angle α ₁ , and the liquid crystal molecules near the alignment film 32 of the upper substrate 24 facing the small angle B have a small angle. α
Pretilt with ₂ .

As described above, in the minute regions A and B,
One of the substrates 22 (2
4) side is pre-tilted at a large angle α ₁ and the other substrate 24 (22) side is pre-tilted at a small angle α ₂ , when a voltage is applied, the liquid crystal molecules in the middle part of the liquid crystal layer are As shown by the arrow, it rises in the direction of larger pretilt.

Therefore, in the minute region A, the rising of the liquid crystal follows the alignment treatment of the alignment film 32 of the upper substrate 24 shown by the arrow R _U in FIG. Further, in the minute region B, the rising of the liquid crystal follows the alignment treatment of the alignment film 36 of the lower substrate 22 shown by the arrow _RL . Therefore, the rising of the liquid crystal in the minute area A in FIG. 6 is the same as that in the minute area A in FIG. This is because even the liquid crystal of the rise in the minute domain A in FIG. 5 arrow R _U
Because it complied with. Similarly, the rising of the liquid crystal in the minute area B in FIG. 6 is the same as that in the minute area B in FIG. Therefore, in the present invention, as described with reference to FIG.
The liquid crystal panel 20 including B can be obtained.

However, the rubbing direction showing the pretilt α ₂ in FIG. 6 is opposite to that in FIG. However, according to the alignment treatment of FIG. 6, since it is sufficient to perform rubbing once for one substrate, it has been found that the alignment state is more stable than when performing rubbing twice. Further, if the patterning of the alignment film 36 is performed according to the procedure of FIG. 1, it is not necessary to use photolithography as in the conventional technique described with reference to FIGS. Is reduced.

Although the letterpress printing method has been described above as an example,
Other printing methods such as offset printing, gravure printing, screen printing, intaglio printing, etc. can also be adopted. FIG. 9 is a diagram showing another embodiment of the present invention. Also in this embodiment, the alignment film 36 on the side of the lower substrate 22 has a two-layer structure, that is, the alignment layer 50 on the lower side and the alignment layer 52 on the upper side. Furthermore, the upper alignment layer 5
2 is made of photosensitive polyimide. Although the alignment film 32 on the upper substrate 24 side is not shown, the alignment film 36 on the lower substrate 22 side is not shown.
It has the same configuration as.

As shown in (A), the lower substrate 22 is coated with the material 52a of the lower orientation material layer 50 and the upper orientation material layer 52 which will become the orientation film 36. Therefore, the material 52a of the upper alignment layer 52 is a mask 110 having a predetermined pattern.
Through. Then, when the exposed or unexposed portion of the material 52a of the upper alignment material layer 52 is removed,
As shown in (B), an alignment material layer 52 on the upper side of a predetermined pattern is formed. Therefore, rubbing is performed as indicated by arrow X. Also in this method, since it is not necessary to use photolithography as in the conventional technique, manufacturing is easy and cost is reduced.

10 to 12 are views showing another embodiment of the present invention, in which the alignment films 3 of the lower substrate 22 and the upper substrate 24 are formed.
This is an example in which the orienting material materials 6 and 32 are applied in a thin linear shape according to a predetermined pattern. Also in this case, the patterned alignment films 36 and 32 are rubbed. Figure 10
Then, the material of the alignment material layer 52 on the upper layer side of the alignment film 36 is injected into the dispenser 120.
Has a needle-shaped nozzle 122. Dispenser 12
When air pressure is applied to 0, the material of the upper alignment material layer 52 is linearly extruded, and the lower alignment material layer 50 of the lower substrate 22 is extruded.
Is attached as an upper orientation material layer 52. The width of the upper alignment layer 52 is about half of one pixel, for example, about 300 μm.

In FIG. 11, the material of the alignment material layer 52 on the upper layer side of the alignment film 36 is injected into the dispenser 124,
The dispenser 120 is a nozzle 12 having a plurality of discharge ports.
Have six. When air pressure is applied to the dispenser 120, the material of the upper alignment material layer 52 is extruded in parallel lines and adheres as the upper alignment material layer 52 on the lower alignment material layer 50 of the lower substrate 22. .

FIG. 12 shows an example in which a discharge device 128 to which an ink jet is applied is used as a means for linearly discharging the material of the alignment material layer 52 on the upper side of the alignment film 36.

[0034]

As described above, according to the present invention,
The alignment state of the liquid crystal can be made different for each minute area, and the pattern corresponding to the minute area of the alignment film can be formed without using photolithography, which simplifies the process and achieves cost reduction. .

[Brief description of drawings]

FIG. 1 is a diagram showing a procedure of a manufacturing method of the present invention.

FIG. 2 is a diagram showing a liquid crystal panel according to an embodiment of the present invention.

FIG. 3 is a diagram showing an active matrix.

FIG. 4 is a diagram showing a portion of a thin film transistor.

FIG. 5 is a diagram showing minute regions having different alignment states of liquid crystal.

FIG. 6 is a diagram showing another example of minute regions in which the alignment state of liquid crystal is different.

FIG. 7 is a diagram showing a conventional method.

FIG. 8 is a diagram showing another conventional method.

FIG. 9 is a diagram showing a second embodiment of the present invention.

FIG. 10 is a diagram showing a third embodiment of the present invention.

FIG. 11 is a diagram showing a fourth embodiment of the present invention.

FIG. 12 is a diagram showing a fifth embodiment of the present invention.

[Explanation of symbols]

 22, 24 ... Substrate 26 ... Liquid crystal 30 ... Common electrode 32, 36 ... Alignment film 34 ... Pixel electrode 50, 54 ... Alignment material layer 52, 56 ... Alignment material layer 100 ... Plate 106 ... Rubbing roller 110 , 120 ... Dispenser 106 ... Rubbing roller 124 ... Ejection device

Front Page Continuation (72) Inventor Kuro Furukawa 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (4)

[Claims] 1. A first and a second opposing substrate (22, 2).
4), a liquid crystal (26), an alignment film (36) provided on the first substrate, and an alignment film (32) provided on the second substrate. A method of manufacturing a liquid crystal panel, wherein the alignment film (36) of the first substrate and the alignment film (32) of the second substrate are subjected to alignment treatment so that the alignment state of the liquid crystal is different for each minute region. A first substrate (22) and the second substrate (24) are prepared, and an alignment film (3) is formed on each of the first substrate and the second substrate.
6, 32) is printed in a predetermined pattern, and the alignment film (3
6, 32) is rubbed. 2. An upper layer in which the alignment film (36) of the first substrate and the alignment film (32) of the second substrate cover the alignment material (50, 54) on the lower layer side and the alignment material on the lower layer side, respectively. A method for manufacturing a liquid crystal panel comprising a side alignment material (52, 56), comprising: an alignment material for forming a lower alignment material layer (50, 54) on each of the first substrate and the second substrate. The material is applied, and the alignment material layer (5, 54) on the lower layer side is coated on the alignment material layer (5, 54) on the upper layer side.
2. The method for manufacturing a liquid crystal panel according to claim 1, wherein an alignment material which is 2, 56) is printed. 3. First and second opposing substrates (22, 2)
4), a liquid crystal (26), an alignment film (36) provided on the first substrate, and an alignment film (32) provided on the second substrate. A method of manufacturing a liquid crystal panel, wherein the alignment film (36) of the first substrate and the alignment film (32) of the second substrate are subjected to alignment treatment so that the alignment state of the liquid crystal is different for each minute region. A first substrate (22) and the second substrate (24) are prepared, and an alignment film (3) is formed on each of the first substrate and the second substrate.
6, 32), a photosensitive alignment material is applied, and the alignment material is exposed through a mask having a predetermined pattern to remove the exposed or unexposed portion of the alignment material. A method for manufacturing a liquid crystal panel, comprising: 4. First and second opposing substrates (22, 2)
4), a liquid crystal (26), an alignment film (36) provided on the first substrate, and an alignment film (32) provided on the second substrate. A method of manufacturing a liquid crystal panel, wherein the alignment film (36) of the first substrate and the alignment film (32) of the second substrate are subjected to alignment treatment so that the alignment state of the liquid crystal is different for each minute region. A first substrate (22) and the second substrate (24) are prepared, and an alignment film (3) is formed on each of the first substrate and the second substrate.
6, 32) is applied in the form of a thin line according to a predetermined pattern, and the alignment film is rubbed.