KR100360042B1 - Manufacturing method of liquid crystal display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and an object thereof is to enable proper alignment treatment without rubbing.

A method of manufacturing a liquid crystal display device comprising a pair of substrates facing each other at intervals, electrodes and alignment films formed on one substrate, electrodes and alignment films formed on the other substrate, and liquid crystals inserted between the pair of substrates. As an example, an alignment film containing a polymer that realizes vertical alignment is formed on the substrate, and the exposure amount of 30 to 120 mJ / cm ² per 1% of the content of the polymer that realizes the vertical alignment of the alignment film is 45 degrees relative to the surface of the alignment film. It is set as the structure which irradiates unpolarized ultraviolet-ray to the said oriented film in the following inclination directions.

Description

Manufacturing method of liquid crystal display device {MANUFACTURING METHOD OF LIQUID CRYSTAL DISPLAY DEVICE}

TECHNICAL FIELD This invention relates to a liquid crystal display device. Specifically, It is related with the alignment processing technique of the alignment film of a liquid crystal display device.

The liquid crystal display device includes a pair of substrates facing each other at intervals, an electrode and an alignment film formed on one substrate, an electrode and an alignment film formed on the other substrate, and a liquid crystal inserted between the pair of substrates. The electrode of one substrate is a common electrode, and the electrode of the other substrate is formed as a pixel electrode. The pixel electrode may be installed together with an active matrix. In addition, the electrode may be provided only on one substrate (for example, IPS mode). A black matrix or a color filter is provided on either substrate.

In a conventional TN liquid crystal display device, the alignment film is rubbed to align the liquid crystal in a predetermined direction. However, since rubbing rubs the alignment layer with a cloth such as rayon, a rash occurs when a cloth such as rayon is brought into a clean room. In addition, static electricity may be generated by rubbing, which may destroy the TFT (thin film transistor) of the active matrix. Therefore, Japanese Patent Application Laid-open No. Hei 9-354940, which is a source of the present application, proposes to perform alignment treatment by ultraviolet irradiation. When the alignment treatment is performed by ultraviolet irradiation, the problem of rubbing can be solved. In this proposal, the alignment film is subjected to the alignment treatment by irradiating non-polarized ultraviolet light to the alignment film of vertical alignment, and destroying a part of the alkyl side chain which realizes vertical alignment. In the case of a horizontal alignment film, it is difficult to realize an alignment process by irradiating an ultraviolet-ray.

When performing the alignment treatment of the alignment film of vertical alignment by irradiating an ultraviolet-ray, a big difference arises in orientation by the exposure amount of an ultraviolet-ray. As a result of examination, it turned out that it is preferable to irradiate an ultraviolet-ray with an appropriate exposure amount. For example, when the exposure amount is less than the appropriate value, the pretilt angle represented by the alignment film is in a high state (closer to the perpendicular to the substrate surface). As a result, when the spacers are scattered to maintain the cell gap of the liquid crystal panel, the orientation of the peripheral portions of the spacers is disturbed by the spacers. For this reason, when displaying, it becomes the same orientation as a black point generate | occur | produced centering around a spacer, and it becomes a display defect.

On the contrary, when the exposure amount is larger than the appropriate value, the pretilt angle represented by the alignment film is in a low state. However, when the exposure amount becomes excessive, a portion that is horizontally oriented on the contrary arises, and a part of the injection root (injection pattern) at the time of liquid crystal injection is generated and traces may remain. In addition, there is a problem that desired vertical alignment cannot be obtained, resulting in horizontal alignment.

When the ultraviolet rays are irradiated onto the surface of the alignment film, the irradiation angle of the ultraviolet rays may not be any angle, and when irradiated at an angle close to the perpendicular to the surface of the alignment film, only a part of the alkyl side chains of the alignment film may be selectively left. As a result, the orientation in the desired direction cannot be obtained.

An object of the present invention is to provide a method for manufacturing a liquid crystal display device capable of performing an appropriate alignment treatment without rubbing.

Another object of the present invention is to provide a method for producing a liquid crystal display device having an alignment film having a plurality of domains in one pixel by one ultraviolet irradiation.

1 is a cross-sectional view of a liquid crystal display device according to an exemplary embodiment of the present invention.

2 is a side view showing an ultraviolet irradiation device.

3 shows the spectral distribution of ultraviolet light used in the apparatus of FIG.

4 is a diagram illustrating a principle of an alignment treatment of an alignment film.

5 is a simplified diagram of FIG. 4.

FIG. 6 is a diagram showing a modification of FIG. 4. FIG.

FIG. 7 is a diagram illustrating a relationship between an exposure amount of ultraviolet rays and a pretilt angle. FIG.

8 is a view showing the relationship of FIG. 7 in which the exposure dose is converted into a value per 1% of the polymer having an alkyl group that realizes vertical alignment;

9 is a diagram illustrating a relationship between an irradiation angle of ultraviolet rays and a pretilt angle.

FIG. 10 is a view showing an alignment process having two domains in one pixel. FIG.

FIG. 11 is a view showing an orientation split achieved by the alignment treatment of FIG. 10. FIG.

FIG. 12 is a diagram illustrating a mask for performing the alignment process of FIGS. 10 and 11.

FIG. 13 shows a modification of FIG. 10. FIG.

14 is a view showing an alignment treatment process of an alignment film according to another embodiment of the present invention.

FIG. 15 is a diagram illustrating a relationship between a mask and a pixel used in FIG. 14. FIG.

FIG. 16 shows a modification of the mask of FIG. 14.

17 is a diagram showing a modification of the mask of FIG. 14.

FIG. 18 is a diagram showing the orientation of liquid crystal molecules in a liquid crystal display device in the case of using a substrate subjected to the alignment treatment described with reference to FIG. 14. FIG.

FIG. 19 relates to another embodiment of the present invention and illustrates an orientation of liquid crystal molecules when a modified alignment treatment is performed. FIG.

20 is a diagram illustrating a step of performing alignment treatment of an alignment film of a color filter substrate for obtaining alignment of the liquid crystal of FIG. 19.

FIG. 21 is a view showing a step of performing an alignment process of an alignment film of a TFT substrate for obtaining alignment of the liquid crystal of FIG. 19. FIG.

FIG. 22 is a diagram showing a modification of the alignment treatment of FIG. 20. FIG.

FIG. 23 is a diagram illustrating a modification of the alignment treatment of FIG. 21.

24 is a plan view showing a mask in the case of performing an alignment process including four domains according to another embodiment of the present invention.

FIG. 25 is a perspective view illustrating one optical path changing portion of the mask of FIG. 24; FIG.

FIG. 26 is a plan view showing an optical path changing portion of FIG. 25; FIG.

FIG. 27 is a cross-sectional view taken along the line XXVII-XXVII of the optical path changing portion of FIG. 26; FIG.

FIG. 28 is a cross-sectional view taken along line XXVIII-XXVIII of the optical path changing portion of FIG. 26; FIG.

29 is a plan view of a modification of the optical path changing portion;

30 is a perspective view illustrating an optical path changing portion of FIG. 29;

FIG. 31 is a perspective view illustrating an example in which a light shielding film is provided in an optical path changing portion of FIGS. 25 and 26.

32 is a plan view and a sectional view of the optical path changing portion of FIG. 31;

[Description of Code]

12,14... Board

16. Liquid crystal layer

18,22... electrode

20,24. Alignment film

60... Orientation processing equipment

62. Light source

68. UV-rays

70... Alkyl group

80... Mask

82... Body part

84. Optical path changing part

The manufacturing method of the liquid crystal display device which concerns on this invention is equipped with a pair of board | substrates which oppose at intervals, the alignment film formed in one board | substrate, the alignment film formed in the other board | substrate, and the liquid crystal inserted in the said pair of board | substrates. A method for producing a liquid crystal display device, comprising: forming an alignment film containing a polymer that realizes vertical alignment on the substrate, and having an exposure amount of 30 to 120 mJ / cm ² per 1% of the content of the polymer that realizes vertical alignment of the alignment film. It is characterized by irradiating unpolarized ultraviolet light to the alignment film in an inclined direction of 45 degrees or less with respect to the surface of the alignment film.

The present invention obliquely irradiates non-polarized ultraviolet light to the surface of the vertical alignment film, thereby realizing an orientation with a pretilt angle without a rubbing process. In the irradiation of the unpolarized ultraviolet-ray by this invention, 30 to per content of the polymer which has the alkyl side chain which makes the direction of irradiation of an ultraviolet-ray 45 degrees or less with respect to the surface of an oriented film, and realizes the vertical alignment property of an oriented film Unpolarized ultraviolet light is irradiated at an exposure dose of 120 mJ / cm ² . That is, the irradiation amount of ultraviolet rays is set according to the actual amount of the alkyl side chain which realizes the vertical alignment of the alignment film.

Thereby, the alignment film can be given an appropriate pretilt angle for vertically aligning the liquid crystal without disturbing the alignment around the spacer and changing the horizontal alignment. In this condition, even if the amount of the polymer having an alkyl side chain that realizes vertical alignment contained in the alignment film changes, an appropriate pretilt angle can be obtained by changing the exposure dose correspondingly.

In the said method, Preferably, the exposure amount of the unpolarized ultraviolet-ray irradiated to the surface of an oriented film is a range of 40-90 mJ / cm <^2> .

In addition, the exposure amount of the unpolarized ultraviolet-ray which irradiates on the surface of an oriented film may be 80-120mJ / cm <^2> .

In addition, the exposure amount of ultraviolet rays causes the pretilt angle of the liquid crystal to the surface of the alignment film to be 89.5 degrees or less. Preferably the pretilt angle of the liquid crystal is in the range of 89.5 degrees to 89 degrees.

Preferably, the wavelength of the ultraviolet light irradiated to the alignment film contains a component of 280 nm or less.

Moreover, the manufacturing method of the liquid crystal display device by another characteristic of this invention is a pair of board | substrates which oppose at intervals, the alignment film formed in one board | substrate, the alignment film formed in the other board | substrate, and the said pair of board | substrates. A method of manufacturing a liquid crystal display device having a liquid crystal inserted into a liver, comprising: an optical film having an alignment film formed on a substrate, provided in the main body portion corresponding to a main body portion and a pixel pitch, and having a refractive index different from that of the main body portion; The surface of each of the alignment films is irradiated with ultraviolet rays in the oblique direction using a mask having a modified portion.

According to this method, the orientation division | segmentation which the molecule | numerator of a liquid crystal aligns in a different direction can be performed in one pixel by one liquid crystal aligning process.

Preferably, each of the optical path changing portions has a sawtooth shape of a two-sided triangular cross section with the length of the pixel pitch as a lower side, and a light shielding film is formed at a portion located at the top of the two-sided triangle of the optical path changing portion. . Alternatively, each of the optical path changing portions has a sawtooth-shaped cross-sectional shape of a trapezoidal cross section whose pixel pitch length is the lower side, and a light shielding film is formed at a portion located at the upper side of the trapezoid.

In this case, the refractive index of the main body portion is n ₁ , the refractive index of the optical path changing portion is n ₂ , the right angle of the sawtooth-shaped cross-sectional shape is θ ₁ , and the angle of incidence of ultraviolet rays irradiated to the alignment film through the optical path changing portion is θ _2. ,

In the case of θ ₁ ≤ 60, the following equation (1) is satisfied.

_{n 1 cos (3θ 1/2} ) = n 2 sin (θ 2/2) -------- (1)

In the case of θ ₁ 60, the following equation (2) is satisfied.

_{n 1 cos (3θ 1/2} ) = n 2 sin (θ 1/2-θ 2) -------- (2)

Further, when the refractive index of the main body portion is n ₁ , the refractive index of the optical path changing portion is n ₂ , and the right angle of the sawtooth-shaped cross-sectional shape is θ ₁ , the following relations exist between them.

cosθ ₁ ≥ n ₂ / n ₁ -------- (5)

The optical path changing portion may be air.

Preferably the body portion of the mask comprises a first flat surface, a second surface opposite the first surface, and a plurality of cavities provided in the second surface, each cavity having the first surface Has a first and a second inclined surface inclined to widen each other in a direction toward the second surface, each cavity has a centerline between the first and the second inclined surface, the optical path changing portion is the cavity and the It is formed by a material contained in the cavity. Ultraviolet light incident on the main body portion from the first surface and transmitted through the first inclined surface is obliquely radiated to the alignment layer in a first direction, and ultraviolet light transmitted through the second inclined surface is different from the first direction on the alignment layer. Irradiation was made at an angle in the opposite second direction.

Next, the present invention provides a pair of substrates opposed to each other, an alignment film formed on one substrate, an alignment film formed on the other substrate, a plurality of bus lines provided on one substrate, and the pair of substrates. A liquid crystal display device manufacturing method having an inserted liquid crystal, comprising: forming an alignment film on a substrate, preparing a mask having a main body portion and a plurality of optical path changing portions provided in the main body portion corresponding to the pixel pitch, and the main body of the mask. The portion includes a first flat surface, a second surface opposite the first surface, and a plurality of cavities provided on the second surface, each cavity being on both sides of a vertical plane perpendicular to the first surface, The first and second inclined surfaces that are inclined to widen each other in a direction from the first surface to the second surface, wherein the optical path changing portion is in the cavity Formed by a material contained in the cavity so that, for one substrate having the bus line, a vertical plane between the first inclined plane and the second inclined plane is on the bus line and the mask is overlaid on the substrate; The ultraviolet-ray is irradiated to the surface of the said oriented film of a board | substrate through the said mask in a diagonal direction, The manufacturing method of the liquid crystal display device characterized by the above-mentioned.

As described above, when the ultraviolet rays are inclined to irradiate the alignment film, the position of the mask and the position of the substrate are appropriately matched, whereby the alignment of the liquid crystal molecules positioned near the bus lines during use is affected by the electric field lines of the bus lines and disturbed. There will be no. Next, the present invention provides a pair of substrates opposed to each other, an alignment film formed on one substrate, an alignment film formed on the other substrate, a plurality of bus lines provided on one substrate, and the pair of substrates. A liquid crystal display device manufacturing method having an inserted liquid crystal, comprising: forming an alignment film on a substrate, preparing a mask having a main body portion and a plurality of optical path changing portions provided in the main body portion corresponding to the pixel pitch, and the main body of the mask. The portion includes a first flat surface, a second surface opposite the first surface, and a plurality of cavities provided on the second surface, each cavity being on both sides of a vertical plane perpendicular to the first surface, The first and second inclined surfaces that are inclined to widen each other in a direction from the first surface to the second surface, wherein the optical path changing portion is in the cavity For another substrate which is formed of a material contained in the cavity and does not have the bus line, an end on the second surface of the first slope and an end on the second surface of the second slope are the bus lines. The superimposition of the mask on the substrate so as to be on the line through the through, and to irradiate the ultraviolet light in the oblique direction on the surface of the alignment film of the substrate via the mask.

Also in this case, when the ultraviolet rays are inclined to irradiate the alignment film, the position of the mask and the position of the substrate are appropriately combined, so that the orientation of the liquid crystal molecules located near the bus lines at the time of use is affected by the electric field lines of the bus lines. It will not be disturbed. And it can use in combination with the orientation process in one board | substrate which has said bus line, and the orientation process in the other board | substrate which does not have a bus line. Or it can use without combining the orientation process in one board | substrate which has the said bus line, and the orientation process in the other board | substrate which does not have a bus line.

Preferably, the cavity has a sawtooth shape of an isosceles triangle cross section, and a light shielding film is formed at a portion located at the top of the isosceles triangle. Alternatively, the cavity has a trapezoidal cross section or sawtooth shape, and a light shielding film is formed at a portion located at an upper side of the trapezoid. In addition, the alignment layer has vertical alignment. The liquid crystal has a Δε <0.

Next, the present invention provides a pair of substrates opposed to each other, an alignment film formed on one substrate, an alignment film formed on the other substrate, a plurality of bus lines provided on one substrate, and the pair of substrates. A liquid crystal display device manufacturing method having an inserted liquid crystal, comprising: forming an alignment film on a substrate, preparing a mask having a main body portion and a plurality of optical path changing portions provided in the main body portion corresponding to the pixel pitch, and the main body of the mask. The portion includes a first flat surface, a second surface opposite to the first surface, and a plurality of cavities provided on the second surface, each cavity being perpendicular to the first surface and perpendicular to each other. First and second inclined surfaces on both sides of the first vertical surface and inclined to widen with each other in a direction from the first surface to the second surface; And third and fourth inclined surfaces on both sides of the second vertical surface and inclined to widen with each other in a direction from the first surface to the second surface, wherein the optical path changing portion is included in the cavity and the cavity. It is formed by a material, and the mask is superimposed on the substrate, to provide a method for manufacturing a liquid crystal display device characterized in that irradiating ultraviolet light in the oblique direction via the mask on the surface of the alignment film of the substrate.

According to this method, the orientation division | segmentation which the molecule | numerator of a liquid crystal aligns in four different directions can be performed in one pixel by one liquid crystal aligning process. Preferably, the cavity has at least one shape of a sawtooth of an isosceles triangle section or a sawtooth of a trapezoid section. In an embodiment, the first and second slopes are inclined planes of isosceles triangles, and the third and fourth slopes are trapezoidal slopes. One board | substrate which has a bus line irradiates an ultraviolet-ray by the said step, and an orientation process is performed, and the other board | substrate which does not have a bus line does not irradiate an ultraviolet-ray by said step.

(Example)

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the liquid crystal display device obtained by this invention. The liquid crystal display device 10 includes a pair of transparent glass substrates 12 and 14 opposed to each other at intervals, and a liquid crystal layer 16 sandwiched between the substrates 12 and 14.

A transparent pixel electrode 18 and a transparent alignment film 20 were formed on one substrate 12, and a transparent common electrode 22 and a transparent alignment film 24 were formed on the other substrate 14. In the substrate 14, a color filter 26 was also formed. Polarizers 28 and 30 are disposed outside the substrate 12 and the substrate 14. The pixel electrode 18 of the substrate 12 is formed with an active matrix, and the data bus lines 32 of the active matrix are shown in FIG. 34 is an insulating film. In addition, an electrode may be provided only in one board | substrate (for example, in IPS mode).

These alignment films 20 and 24 are alignment films which exhibit vertical alignment, and as described below, alignment with pretilt angle without rubbing was realized.

2 shows an orientation processing apparatus 60 for these alignment films 20 and 24. The alignment processing apparatus 60 becomes the holder 66 which supports the light source 62 which irradiates unpolarized ultraviolet-ray, the mirror 64, and the board | substrates 12 and 14 in which the alignment films 20 and 24 were formed. The holder 66 supports the substrates 12 and 14 at an angle with respect to the optical axis. That is, parallel ultraviolet rays from the light source 62 are incident on the alignment films 20 and 24 at an angle of 45 degrees (or 45 degrees or less).

The light source 62 includes the parabolic reflector 62a and irradiates almost unpolarized ultraviolet light in parallel. A preferred spectral distribution of the light source 62 is shown in FIG. 3. This spectral distribution has a peak near wavelength 250nm. It is preferable that the ultraviolet-ray to irradiate contains the component of wavelength 280nm or less. The alignment films 20 and 24 treated by the orientation processing apparatus 60 are alignment films which show vertical alignment property, and the orientation accompanying a pretilt angle is implement | achieved by irradiating unpolarized ultraviolet-ray from a diagonal direction.

The alignment films 20 and 24 are alignment films which exhibit vertical alignment in a coated and fired state, and contain polymers shown below.

FIG. 4 is a diagram showing the principle of an orientation process, and FIG. 5 is a simplified diagram of FIG. 4. The alignment films 20 and 24 represented by the general formula (1) contain a polymer having an alkyl side chain (alkyl group) R which realizes vertical alignment. Alkyl group R is shown at 70 in FIG. The alkyl group 70 is considered to protrude irregularly on the surfaces of the alignment films 20 and 24.

The ultraviolet rays 68 are irradiated obliquely with respect to the alignment films 20 and 24 in the direction of X, and the pretilt direction (orientation line) of the liquid crystal becomes an orientation parallel to the incident orientation of the ultraviolet rays 68. Unpolarized ultraviolet light 68 includes polarizations of P and S waves, but S waves do not contribute to the orientation of orientation. That is, the S wave acts in the Y direction without any action in the X direction, but the action does not contribute to the orientation of the orientation because the magnitude of the action is the same in the plus and minus directions of the Y axis.

The P wave acts on the portion containing the alkyl group 70 in a plane parallel to the direction of incidence of the ultraviolet ray 68 to influence the orientation of the orientation. FIG. 5 is a part of FIG. 4 taken along a plane parallel to the direction of incidence of ultraviolet light 68, ie, a plane parallel to the vibration plane of the P wave. In FIG. 5, the alkyl group 70 may be divided into two inclined in opposite directions with respect to the vibration direction of the P wave of the ultraviolet ray 68.

The component a in the alkyl group 70 is inclined to be perpendicular to the vibration direction of the P wave, and the component b in the alkyl group 70 is inclined to be horizontal to the vibration direction of the P wave. In general, it is difficult to think that the alkyl group itself is destroyed by ultraviolet rays. It is easy to understand when the part supporting an alkyl group or the part which tilts an alkyl group is destroyed by an ultraviolet-ray. The portion a (corresponding to component a) in which the alkyl group is inclined to be perpendicular to the vibration direction of the P wave and the portion b (corresponding to component b) in which the alkyl group is inclined to be parallel to the vibration direction of the P wave are The rate of destruction by ultraviolet rays is different.

The part b which makes the alkyl group incline is easy to receive energy, and is easy to be destroyed by the energy of an ultraviolet-ray. Therefore, component b decreases by irradiation of ultraviolet rays, and component a remains unbroken. Therefore, when the alignment films 20 and 24 are used in the liquid crystal display device 10, the liquid crystal molecules are pretilted according to the inclination of the component a in the alkyl group 70 of the alignment films 20 and 24.

6 is a diagram illustrating a modification of FIG. 5. In FIG. 5, it is assumed that the components a and b of the alkyl group 70 are uniformly irradiated with ultraviolet rays. However, FIG. 6 shows that some aa and bb of the components a and b of the alkyl group 70 are particularly strongly irradiated. In case of action. These portions aa and bb are each bent in reverse with respect to most of the components a and b of the alkyl group 70.

Therefore, the portion aa is easily destroyed by the energy of ultraviolet rays, but the portion bb is difficult to be destroyed by the energy of ultraviolet rays. Thus, the component b having the portion bb remains, and the alignment layers 20 and 24 are used in the liquid crystal display device 10. The lower liquid crystal molecules are pretilted in accordance with the inclination of the component b in the alkyl group 70 of the alignment layers 20 and 24. In either case of FIG. 5 and FIG. 6, the liquid crystal molecules are aligned with a constant pretilt angle. Therefore, in the case of the vertical alignment film, the alignment with the pretilt angle can be realized by irradiating the unpolarized ultraviolet light obliquely without rubbing.

However, in FIG. 5 and FIG. 6, it may be difficult to determine which of the a component and the b component is easily destroyed before the ultraviolet irradiation. However, when the ultraviolet rays are irradiated obliquely, one of the a component and the b component is destroyed, and the other remains, whereby the liquid crystal molecules are aligned with the pretilt angle without rubbing when used as the liquid crystal display device 10.

As a feature of the present invention, the amount of exposure of ultraviolet rays when irradiated with ultraviolet rays is determined within the range of 30 to 120 mJ / cm ² per 1% (per 1% by weight) of the polymer that realizes the vertical alignment of the alignment films 20 and 24. All. The above formula (1) shows an example of a polymer which realizes the vertical alignment of the alignment films 20 and 24, and the alignment film contains polymers other than the polymer represented by the formula (1). The other polymer does not contain a component that realizes vertical alignment such as, for example, the alkyl group 70, and has, for example, a structure in which the alkyl group 70 is substituted with a hydrogen group. In this invention, content of the polymer which implements the vertical alignment property with respect to all the polymers which comprise the oriented films 20 and 24 is investigated, and the irradiation amount of an ultraviolet-ray is set with respect to 1% of its content.

In the Example, the sample containing 25% and the sample containing 65% of the polymer which realizes the vertical alignment property of the alignment film 20,24 were prepared, and it was set as the alignment film 20,24. First, the materials of the vertical alignment films 20 and 24 were applied to the substrates 12 and 14 by spin coating at 1500 rpm. At this time, the film thicknesses of the alignment films 20 and 24 are about 500 GPa. This was baked at 180 degreeC for 1 hour. Next, ultraviolet rays were irradiated to the alignment films 20 and 24 at an angle of 45 degrees with respect to the surfaces of the alignment films 20 and 24 using the alignment treatment apparatus 60 of FIG. 2. At this time, a deep UV irradiation device made by Ushio Electric was used as the light source 62. In this light source 62, the size of the ultraviolet light emitting site was about 5 mm, and the parallel light was obtained by the reflector 62a.

Here, a plurality of samples irradiated with an exposure dose of three or four ultraviolet rays in the range of 30 to 120 mJ / cm ² per 1% of the content of the polymer having the alkyl group 70 to realize the vertical alignment of the alignment films 20 and 24 are made, and the liquid crystal Assembled as a display device. The first group was 25 percent sample of polymer and the second group was 65 percent sample.

FIG. 7 is a diagram showing the relationship between the exposure amount and the pretilt angle of the sample thus prepared. Samples of the first group were constructed with curve X. Two samples of the first group were irradiated with ultraviolet rays at an exposure dose in the range of 500 to 2500 mJ / cm ² . Samples of the second group were constructed with curve Y. The sample of the 2nd group irradiates an ultraviolet-ray with the exposure amount in the range of 1200-6000 mJ / cm <^2> .

When the orientation of the liquid crystal is observed with respect to the above sample, in the case where the exposure amount is generally small (the area on the left end side in FIG. 7), black spots due to the orientation disturbance occur around the inserted spacer to maintain the cell gap, and the exposure amount is large. The injection root (injection stripe) at the time of liquid crystal injection appeared in the area of the right end side of FIG. The absence of black spots (black spots) or injection streaks is considered to be good alignment of liquid crystals.

About the sample of a 1st group, the thing of the range P of FIG. 7 was judged as favorable of the orientation of a liquid crystal. About the sample of a 1st group, the thing of the range P irradiates an ultraviolet-ray with the exposure amount in the range of 1000-2200mJ / cm <^2> . For the samples of the second group, those in the range Q of FIG. 7 were judged to be good in orientation. About the sample of the 2nd group, the thing of the range Q irradiated with ultraviolet-ray by the exposure amount in the range of 2400-5500mJ / cm <^2> .

FIG. 8: is a figure which shows the relationship of FIG. 7 which converted the exposure amount into the value per 1% of polymers which have an alkyl group which implements a vertical alignment property. That is, the exposure amount of FIG. 7 was divided by 25 about the 1st sample, and the exposure amount of FIG. 7 was divided by 65 about the 2nd sample, and it was set as the exposure amount per 1% of polymers. Curve X showing the relationship between the samples of the first group of FIG. 7 is plotted as curve X 'in FIG. The exposure amount P 'which obtained the favorable result of the orientation of a liquid crystal was in the range of 40-88 mJ / cm <^2> per 1% of polymers which have an alkyl group which implements a vertical alignment property. Curve Y representing the relationship between the samples of the second group of Fig. 7 is plotted as curve Y 'in Fig. 8. The exposure amount Q 'which obtained the favorable result of the orientation of a liquid crystal was in the range of 37-85 mJ / cm <^2> per 1% of polymers which have an alkyl group which implements a vertical alignment property.

From this result, even if the content of the polymer having an alkyl group for realizing the vertical alignment in the materials of the alignment films 20 and 24 is changed, if the exposure amount per 1% of the polymer having the alkyl group for realizing the vertical alignment is within a predetermined range, It can be seen that good results of the orientation can be obtained. It was found that the preferred exposure dose is in the range of 40 to 90 mJ / cm ² .

In the assembly of the liquid crystal display device, the liquid crystal 16 is injected between the pair of substrates 12 and 14, and the injection hole is sealed. The above embodiment is the result of testing by applying a voltage between the electrodes 18 and 22 as the liquid crystal display in this state. After injecting the liquid crystal 16 between the pair of substrates 12 and 14, sealing the nipple, and then applying heat to the liquid crystal panel to anneal the liquid crystal, the alignment of the liquid crystal is improved. As a result, the favorable result of the orientation of a liquid crystal can be obtained in the range of exposure amount wider than the range of said exposure amount. Table 1 below shows the results in this case.

From this result, when ultraviolet-ray was irradiated with the exposure amount of 30-120mJ / cm <^2> per 1% of content of the polymer which realizes the vertical alignment property of an oriented film, it turned out that the favorable result of the orientation of a liquid crystal can be obtained. In addition, when ultraviolet rays are irradiated at an exposure amount of 80 to 120 mJ / cm ² per 1% of the polymer for realizing the vertical alignment of the alignment films 20 and 24, the pretilt angle of the liquid crystal molecules becomes 89 degrees or less, so that the function of the vertical alignment film is stable. Thus, the generation of domains due to the transverse electric field can be prevented. As this exposure amount, the pretilt angle was in the range of about 89.6 degrees-89 degrees.

Here, the generation of the domain due to the transverse electric field will be described. Liquid crystals oriented at the pretilt angle close to the vertical by the alignment films 20 and 24 are likely to be affected by the transverse electric field from the bus line or the like of the substrate having the TFT. Lose. In order to reduce the influence of the transverse electric field, it is necessary to set the pretilt angle of the alignment film to the surface of the alignment film as small as possible. However, it is not necessary to lower the pretilt angle only. If the pretilt angle is somewhat small (for example, about 85 degrees), the blackness is lowered when the polarizer is attached to the cross nicol and the black mark is displayed. Contrast decreases.

As shown in FIG.7 and FIG.8, the pretilt angle in the case of irradiating unpolarized ultraviolet-ray shows the tendency to fall as irradiation amount increases. As shown in Fig. 9, the pretilt angle tends to decrease as the irradiation angle of unpolarized ultraviolet light becomes shallow with respect to the alignment film surface. Therefore, under all irradiation conditions, when the alignment film containing 25% of the polymer containing the alkyl group was irradiated and applied to the TFT panel, in the case of the irradiation conditions with an irradiation angle of 10 degrees and an exposure amount of about 1800 mJ / cm ² , the generation of domains was extremely A small good indication could be obtained. The pretilt angle at this time was about 89 degrees with respect to the alignment film surface.

In order to make the influence of the transverse electric field as small as possible, a pretilt angle of 89 degrees or less is required. For this purpose, about 80 mJ / cm <^2> or more of ultraviolet irradiation amount with respect to an oriented film is needed with respect to 1% of polymers containing an alkyl group in an oriented film. However, as described above, when the amount of ultraviolet irradiation is too large, there is a problem that an injection root occurs when the liquid crystal is injected, and the trace remains. In FIG. 8, the injection root remains at 90 mJ / cm ² or more, but by annealing after injection as described above, a pretilt angle of 89 degrees or less can be obtained in the range of about 80 to 120 mJ / cm ² without the injection root. It becomes investigation condition.

The spectral distribution shown in FIG. 3 contained the wavelength component of 250 nm vicinity, and this component was effective. As such a light source, a short arc type lamp is used, and ultraviolet rays in the vicinity of 250 nm are mainly used, and the parallelism of the ultraviolet rays is set to ± 10 degrees or less, preferably ± 3 degrees or less by a reflector. When the test using the light source light which has the spectral distribution shown in FIG. 3 as it was, and the test which irradiated the ultraviolet-ray which cut off the wavelength component of 300 nm or more in this light source light were compared, the result was compared and the same pretilt expression property was confirmed. From this result, it turned out that it is effective to irradiate the ultraviolet-ray below 280 nm in order to express pretilt to the vertical alignment film 20,24.

9 is a diagram illustrating a relationship between an irradiation angle of ultraviolet rays and a pretilt angle. The amount of exposure is irradiated with ultraviolet light at an exposure amount of 1800 mJ / cm ² to the alignment films of the first group of samples (25%) and the second group of samples (65%). Tested against. When ultraviolet irradiation is performed at an angle of 45 degrees or less with respect to the surface of the alignment film, it can be seen that good orientation is obtained. Regarding the pretilt angle, a lower pretilt angle can be obtained as the irradiation angle to the surface of the alignment film is lower. In this case, the pretilt angle in the irradiation angle in which the orientation of the liquid crystal became good became 89.5 degrees or less. Considering the above, in order to prevent the adverse influence of the orientation by a spacer, it is good to set it as the pretilt angle of 89.5 degrees or less.

In this embodiment, pretilt expression can be imparted to the vertical alignment films 20 and 24 by using unpolarized ultraviolet light. In fact, the only effective P wave in unpolarized ultraviolet light is still effective. However, there is a great advantage in that unpolarized ultraviolet light can be used. Conventionally, there has been a proposal to impart pretilt expression by irradiating a polarized ultraviolet ray to a horizontal alignment film. In this case, pretilt expression cannot be obtained by using an unpolarized ultraviolet ray. Therefore, a polarizer is needed to obtain polarized ultraviolet rays. Such a polarizer is currently only a gle-taylor type polarizer. It is not suitable for practical use. Therefore, it is extremely preferable that the polarization treatment can be performed using unpolarized ultraviolet rays because there is no need to use a polarizer for ultraviolet irradiation.

In this embodiment, unpolarized ultraviolet rays are uniformly irradiated on the entire surface of the vertical alignment layers 20 and 24. Therefore, in order to perform alignment division having domains A and B of two different orientation directions within one pixel, as shown in FIG. 10, ultraviolet rays 68A and 68B are irradiated in opposite directions for each of the divided domains A and B. Do it. In this way, as shown in FIG. 11, two domains (A, B) in which the liquid crystal molecules located in the middle tilt in the opposite direction can be obtained. In this case, there is no difference in the pretilt angle of the liquid crystal molecules in the two domains (A, B). By dividing the orientation, the visual characteristic is improved.

12 shows an example of irradiating ultraviolet rays 68A and 68B simultaneously in opposite directions for each of the domains A and B. In FIG. In this case, a mask 74 having an opening 74A is used. The ultraviolet rays 68A and 68B in the opposite direction enter from one opening 74A, but the conditions under which the ultraviolet rays 68A and 68B in the opposite direction are equally divided into the two domains A and B are as follows. The pitch (pitch of one pixel) of the opening 74A of the mask 74 is P, the interval between the mask 74 and the alignment films 20, 24 is Q, and the incident angles of the ultraviolet rays 68A, 68B are θ. Let Q = (P / 4) sinθ.

As shown in Fig. 13, by applying this principle, four different domains (Aa, Ab, Ba, Bb) can be formed in one pixel by irradiating ultraviolet rays simultaneously in four directions. In this case, one pixel is divided into a plurality of domains (Aa, Ab, Ba, Bb), and the alignment direction of the liquid crystals of the plurality of domains (Aa, Ab, Ba, Bb) is located at the center of the pixel as indicated by the arrow. Facing radially. In Fig. 13, the alignment direction of the liquid crystal is directed outward from the center of the pixel as indicated by the arrow. The alignment direction of the liquid crystal may be directed inward toward the center of the pixel. As such, by providing four domains Aa, Ab, Ba, and Bb in one pixel, visual characteristics can be improved.

14 is a diagram showing an alignment treatment process of an alignment film according to another embodiment of the present invention. As shown in FIG. 1, the embodiment includes a pair of substrates 12 and 14, electrodes 18 and 20 and an alignment film formed on one substrate, and electrodes 22 and an alignment film formed on the other substrate. Applicable to the liquid crystal display device having the liquid crystal 16 inserted between the 24 and the pair of substrates 12 and 14. While the alignment films 20 and 24 are aligned by irradiating the ultraviolet light obliquely as in the previous embodiment, the alignment films 20 and 24 include two domains A and B in one pixel, as shown in FIG. It is.

In the present embodiment, the mask 80 is used when the alignment films 20 and 24 are formed on the substrates 12 and 14 at the time of manufacturing the liquid crystal display, and then irradiated with obliquely ultraviolet rays. The mask 80 has a body portion 82 and an optical path changing portion 84 embedded in the body portion 82 and having a refractive index different from that of the body portion 82. Each of the optical path changing portions 84 has a sawtooth shape of an isosceles triangle cross section, and the length h of the bottom side corresponds to the length of the pixel pitch. In addition, the light shielding film 86 was formed in the part located at the top of the isosceles triangle of the optical path changing part 84.

FIG. 15 is a diagram illustrating a relationship between a mask 80 and pixels used in FIG. 14. One of the first and second substrates 12 and 14 is a TFT substrate, and the TFT substrate has a pixel electrode 18, a drain bus line 32, and a gate bus line 33. The TFT (not shown) is provided at the intersection of the drain bus line 32 and the gate bus line 33. The pixel pitch h is the distance between the centers of two adjacent drain bus lines 32, and the length h of the bottom side of the optical path changing portion 84 corresponds to the pixel pitch i. In addition, the pixel pitch h may be set as the distance between the centers of two adjacent gate bus lines 33.

In Fig. 14, the mask 80 is disposed so that the bottom of the isosceles triangle of the optical path changing portion 84 is above the alignment films 20 and 24, and parallel ultraviolet rays are perpendicular to the alignment film 20 as indicated by the arrows. It is incident on the mask 80 in the in direction. Incident ultraviolet light is reflected on the inclined plane of the isosceles triangle of the optical path changing portion 84, and is directed to the inclined plane of the isosceles triangle of the neighboring optical path changing portion 84, and enters the optical path changing portion 84 from the inclined plane.

Here, with respect to the three optical path changing portions 84A, 84B and 84C, the ultraviolet rays reflected from the inclined surface on the right side of the left optical path changing portion 84A face the inclined surface on the left side of the central optical path changing portion 84B. And enters the optical path changing portion 84B from the inclined surface. On the other hand, the ultraviolet rays reflected from the inclined surface on the left side of the right optical path changing portion 84C face the inclined surface on the right side of the central optical path changing portion 84B and enter the optical path changing portion 84B from the inclined surface. Ultraviolet rays incident on the optical path changing portion 84B from the inclined surface on the left side and the inclined surface on the right side of the central optical path changing portion 84B are obliquely incident on the surfaces of the alignment films 20 and 24. Therefore, as in the above embodiment, by aligning the alignment films 20 and 24 with ultraviolet rays obliquely, the alignment films 20 and 24 can be subjected to alignment treatment.

The shape of the isosceles triangle of the optical path changing portion 84 and the light shielding film 86 are reflected on the inclined surface on the right side of the left optical path changing portion 84A, and the ultraviolet rays incident on the inclined surface on the left side of the central optical path changing portion 84B. Through this optical path changing portion 84B, it was formed so as to be incident on half of the regions of the alignment films 20 and 24. Similarly, ultraviolet rays reflected from the inclined surface on the left side of the right optical path changing portion 84C and incident on the inclined surface on the right side of the central optical path changing portion 84B pass through the optical path changing portion 84B to form the alignment films 20 and 24. It was formed to be incident on the other half of the region. Therefore, the orientation splitting is performed as described with reference to FIGS. 10 and 11.

Here, the refractive index of the main body portion 82 is n ₁ , the refractive index of the optical path changing portion 84 is n ₂ , and the right angle of the sawtooth-shaped cross-section (the right angle of the isosceles triangle) is θ ₁ , and the optical path changing portion 84 When the incident angle of ultraviolet rays irradiated to the alignment film 20 through θ ₂ ,

In the case of θ ₁ ≤ 60, the following expression 1 is satisfied.

For θ ₁ 60, the following equation 2 is satisfied.

In addition, in order to achieve the orientation division, when the pitch of the sawtooth-shaped optical path changing portion 84 of the isosceles triangle section is set to h, the light shielding film 86 has the height ( i)

16 is a diagram illustrating a modification of the mask 80. The mask 80 has a body portion 82 and an optical path changing portion 84 embedded in the body portion 82 and having a refractive index different from that of the body portion 82. In this case, the light path changing portion 84 has a sawtooth-shaped cross-sectional shape of a trapezoidal cross section, and a light shielding film 86 is formed at a portion located on the upper side of the trapezoid. Considering that the trapezoid is cut out of the top of the isosceles triangle in FIG. 14, the trapezoidal inclined plane and the light shielding film 86 function similarly to the embodiment of FIG. 1.

In this case, when the two trapezoidal diagonal lines are extended and the right angle formed by the extension line is the right angle θ ₁ of the sawtooth cross-sectional shape, the above equations 1 and 2 also apply to the trapezoidal case. Apex angle θ ₁ may guhaedo using the necessary extension is not formed, the angle between the oblique sides of the trapezoid and the base is a (π -θ ₁₎ / 2.

And in the case of a trapezoid, the length j of the light shielding film 86 is a dimension of the upper side of a trapezoid, and is represented by following formula (4).

In the case of an isosceles triangle or a trapezoid, when the refractive index of the main body portion 82 is n ₁ , the refractive index of the optical path changing portion 84 is n ₂ , and the right angle of the sawtooth-shaped cross-sectional shape is θ ₁ , they are There is a relationship between the following equations.

Here, a concrete example is demonstrated. The material of the main body portion 82 of the mask 80 was glass having a refractive index n ₁ = 1.5, and the optical path changing portion 84 was air having a refractive index n ₂ = 1.0. That is, the main body portion 82 of the mask 80 had a concave portion shape corresponding to the optical path changing portion 84, and the concave portion contained air.

The pixel pitch h is 100 micrometers, for example, and the optical path changing part 84 was similarly formed in the pitch of 100 micrometers continuously. When irradiating the alignment layers 20 and 24 with ultraviolet rays, as shown in FIG. 15, the top of the isosceles triangle of the optical path changing portion 84 of the mask 80 is positioned at the center of the pixel electrode 18 (or The lower angle portion of the isosceles triangle is positioned at the center of the bus line 32), and the mask 80 is brought into close contact with the substrates 12 and 14 on which the alignment layers 20 and 24 are formed.

If through a mask (80) parallel irradiated with UV light and the angle between the inclined surface of the light-path change portion 84 at the time of ultraviolet light is incident first on the slope of the light-path change portion 84 of the mask 80 is θ _1/2 Becomes

When the right angle θ ₁ of the isosceles triangle is 50 degrees, parallel ultraviolet rays are irradiated perpendicularly to the upper surface of the mask 80 from the upper surface of the mask 80 to the inclined surface of the optical path changing portion 84. Incident at 65 degrees (25 degrees with respect to the inclined plane). Ultraviolet rays incident at this angle are totally reflected because the incident angle exceeds the critical angle of 41.8 degrees (cosθ = 0.666) at the interface. The reflected light enters the inclined plane of the neighboring optical path changing portion 84 at an incident angle of 15 degrees, and enters the optical path changing portion 84 after refraction. The ultraviolet light transmitted through the optical path changing portion 84 is incident on the surfaces of the alignment films 20 and 24 at an angle of about 47.8 degrees. In order for the ultraviolet rays incident from both inclined surfaces of the optical path changing portion 84 to irradiate half of the surfaces of the alignment films 20 and 24, respectively, the height i of the light shielding film 86 needs to be 23.94 m. The light shielding film 86 is formed of carbon black or the like.

In this way, reflection and refraction occur at the interface between the main body portion 82 and the optical path changing portion 84, and the alignment film is irradiated at an angle of about 47.8 degrees. Thus, within one pixel, half of the alignment film is irradiated at an angle of about 47.8 degrees, and the other half is irradiated at an angle of about 47.8 from the opposite direction. Therefore, by one ultraviolet irradiation, the alignment films 20 and 24 are irradiated by dividing at an angle of about 47.8 degrees from the opposite direction. Thus, the board | substrates 12 and 14 which have the alignment film 20 and 24 formed in this way are bonded together, a liquid crystal is inject | poured, and a panel is formed. The electrodes may be provided on both substrates, or may be provided only on one substrate.

When the angle θ ₁ of the right angle of the isosceles triangle is 44 degrees, the incident angle θ ₂ with respect to the alignment films 20 and 24 is 59.8 degrees. At this time, the height i = O of the light shielding film 86 is satisfied, and the light shielding film 86 is not necessary. 17 shows this state.

The configuration described with reference to FIGS. 14 to 17 may be modified as follows. The body portion 82 of the mask 80 includes a first flat surface 82a, a second surface 82b on the opposite side of the first surface 82a, and a plurality of cavities 82c provided on the second surface 82b. ). Each cavity 82c has first and second inclined surfaces 82d and 82e that are inclined to widen each other in a direction from the first surface 82a to the second surface 82b.

Each cavity 82c has a centerline between the first inclined plane 82d and the second inclined plane 82e, and the optical path changing portion 84 is caused by a material (eg, air) contained in the cavity 82c and the cavity 82c. Is formed. Therefore, the ultraviolet ray incident on the main body portion 82 from the first surface 82a and transmitted through the first inclined surface 82d is irradiated obliquely on the alignment film 20 in the first direction, and transmitted through the second inclined surface 82e. One ultraviolet ray is irradiated obliquely on the alignment film 20 in a second direction opposite to the first direction.

FIG. 18 illustrates the orientation of liquid crystal molecules in the liquid crystal display device 10 when the substrate 12 subjected to the alignment treatment described with reference to FIG. 14 is used. For example, as described with reference to FIG. 1, one substrate (TFT substrate) 12 has a pixel electrode 18, a data bus line 32, a gate bus line, and an alignment film 20, and the other substrate ( The color filter substrate 14 has a common electrode 22 and an alignment film 24. The other substrate 14 does not have a bus line. However, the other substrate 14 has a black matrix or the like 32B at a position corresponding to the data bus line 32 and the gate bus line of one substrate 12. Therefore, also in the other board | substrate 14, the position corresponding to the data bus line 32 and the gate bus line can be specified.

In FIG. 14, in the orientation processing step, the data bus lines 32 are located at the bottom (both sides of the base) of a quadrilateral or trapezoidal quadrangle forming the optical path changing portion 84 of the mask 80. The spacing of two adjacent data bus lines 32 corresponds to the pixel pitch. The black matrix 32B at the position corresponding to the bus line is also in the vertical plane that includes the data bus line 32. The center of the right angle or trapezoid top surface of the isosceles triangle is in the middle of two adjacent data bus lines 32.

In Fig. 14, ultraviolet rays are irradiated to the domain A in one pixel from the upper left to the lower right, and ultraviolet rays are irradiated to the domain B from the upper right to the lower left. The irradiation direction of ultraviolet rays determines the direction of the pretilt of the liquid crystal molecules at the time of use of the liquid crystal display device 10. As a result, as shown in Fig. 18, the liquid crystal molecules 16A of the domain A in one pixel are trying to pretilt from the upper left to the lower right, and the liquid crystal molecules 16B of the domain B are pretilted from the upper right to the lower left. . When a voltage is applied, the liquid crystal molecules fall in the direction of the arrow according to the pretilt direction. Although not shown about the alignment process of the alignment film of the other board | substrate 14, the alignment process of the alignment film of the other board | substrate 14 is carried out of the one board | substrate 12 so that a liquid crystal molecule may perform the same behavior in each domain A, B. It is performed in accordance with the alignment treatment of the alignment film.

As shown in FIG. 18, when a voltage is applied, not only an electric field is generated between the pixel electrode 18 and the common electrode 22, but also between two adjacent data bus lines 32 (and between gate bus lines). Electric line EL is produced. The electric field line EL extends to traverse one pixel laterally, and the liquid crystal molecules 16C at positions adjacent to the data bus line 32 (gate bus line) are affected by this electric field line EL. The liquid crystal molecules 16C fall down along the electric field line EL, which is opposite to the direction in which the liquid crystal molecules 16A in the domain A to which the liquid crystal molecules 16C belong fall. Therefore, there is a problem that delineation occurs in the display in the portion adjacent to the data bus line 32 (gate bus line).

It is a figure which shows the orientation of the liquid crystal molecule when the modified orientation process is performed. In FIG. 19, the liquid crystal molecules 16A of the domain A in one pixel attempt to pretilt in the lower left direction from the upper right, and the liquid crystal molecules 16B of the domain B pretilt in the lower right direction from the upper left. When a voltage is applied, the liquid crystal molecules fall in the direction of the arrow according to the pretilt direction. That is, the alignment processing in FIG. 19 is performed in the reverse direction from the alignment processing in FIG. 18 in one pixel on the basis of the data bus line 32. Therefore, in Fig. 19, the liquid crystal molecules 16C at positions adjacent to the data bus lines 32 (gate bus lines) fall down in the direction along the electric field lines EL, but this is because of the domain A to which the liquid crystal molecules 16C belong. The liquid crystal molecules 16A fall in the same direction. Therefore, even when the portion is adjacent to the data bus line 32 (gate bus line), the display delinquency does not occur.

FIG. 20 is a diagram illustrating a step of performing alignment treatment of the alignment film of the color filter substrate 14 having no bus line for obtaining the alignment of the liquid crystal of FIG. 19. Similarly, FIG. 21 is a diagram showing a step of performing alignment processing of the alignment film of the TFT substrate 12 having the bus lines for obtaining the alignment of the liquid crystal of FIG. 19. In this embodiment, the alignment films 20 and 24 are formed on the substrates 12 and 14, but the illustration of the alignment films 20 and 24 is omitted. As described with reference to FIGS. 14 to 17, the alignment films 20 and 24 are subjected to alignment treatment by irradiating ultraviolet rays in the oblique direction. In this embodiment, the positional relationship between the mask 80, the data bus line 32 (and the gate bus line), the black matrix and the like 32B is different from the previous example in performing the alignment process.

20 and 21 show a case where the optical path changing portion 84 of the mask 80 is an isosceles triangle. After the alignment films 20 and 24 are formed on the substrates 12 and 14, the mask 80 having the main body portion 82 and the plurality of optical path changing portions 84 provided in the main body portion in correspondence with the pixel pitch is provided. Prepare. The body portion 82 of the mask 80 includes a first flat surface 82a, a second surface 82b on the opposite side of the first surface 82a, and a plurality of cavities 82c provided on the second surface 82b. ). Each cavity 84c is on both sides of a vertical plane perpendicular to the first surface 82a (the plane perpendicular to the ground in FIG. 20 and passing through the right angle of the isosceles triangle), the second surface at the first surface 82a The first and second inclined surfaces 82d and 82e are inclined to widen with each other in a direction toward 82b, and the optical path changing portion 84 is formed by the cavity 84c and the material (air) contained in the cavity. do.

In FIG. 20, for the color filter substrate 14 having no bus line, an end portion (low angle portion of an isosceles triangle) and a second surface of the second inclined surface 82e on the second surface 82b of the first inclined surface 82d. The mask 80 is placed on the substrate 14 so that the end on 82b is on the black matrix 32B. In other words, the right angle of the isosceles triangle is in the middle of two adjacent data bus lines 32. When ultraviolet rays are irradiated in the oblique direction through the mask 80 on the surface of the alignment film 24 of the substrate 14, the liquid crystal molecules are aligned with the pretilt in the oblique direction.

In FIG. 21, for the TFT substrate 12 having the bus lines, the mask 80 is placed on the substrate 12 so that the vertical plane between the first inclined plane 82d and the second inclined plane 82e is on the data bus line 32. Put it up. In other words, the right angle of the isosceles triangle is placed at the position overlapping on the data bus line 32. When ultraviolet rays are irradiated in the oblique direction through the mask 80 on the surface of the alignment film 24 of the substrate 14, the liquid crystal molecules are aligned with the pretilt in the oblique direction. One pixel in this case is not an area defined by the base of the isosceles triangle, but an area defined by two adjacent data bus lines 32.

When the color filter substrate 14 of FIG. 20 and the TFT substrate 12 of FIG. 21 are bonded together, and the liquid crystal 16 is injected between these substrates 12 and 14, the orientation of the liquid crystal shown in FIG. 19 is obtained. The data bus line 32 and the black matrix lamp 32B are located in the same plane. Even if the color filter substrate 14 does not have a black matrix lamp 32B, when assembling, it is sufficient to provide a positioning mark that comes in the same plane as the data bus line 32 in the color filter substrate 14 during assembly. Since it is performed using precision tools, such as a stepper, it is not necessary to necessarily provide such a positioning mark in the same pitch as the data bus line 32. FIG.

22 and 23 are examples of the case where the optical path changing portion 84 of the mask 80 is trapezoidal. Other features are the same as those of FIGS. 20 and 21. In FIG. 22, for the color filter substrate 14 having no bus line, an end (end of the trapezoidal bottom) on the second surface 82b of the first inclined plane 82d and a second surface of the second inclined plane 82e ( The mask 80 is placed on the substrate 14 with the end on 82b) being on the black matrix 32B. In short, the trapezoidal center lies in the middle of two adjacent data bus lines 32. When ultraviolet rays are irradiated in the oblique direction through the mask 80 on the surface of the alignment film 24 of the substrate 14, the liquid crystal molecules are aligned with the pretilt in the oblique direction.

In FIG. 23, for the TFT substrate 12 having the bus lines, the mask 80 is placed on the substrate 12 so that the vertical plane between the first inclined plane 82d and the second inclined plane 82e is on the data bus line 32. Put it up. In short, the center of the trapezoid is at the position where it overlaps on the data bus line 32. When ultraviolet rays are irradiated in the oblique direction through the mask 80 on the surface of the alignment film 24 of the substrate 14, the liquid crystal molecules are aligned with the pretilt in the oblique direction.

If one alignment film of the pair of opposing alignment films is properly aligned, the other alignment film is aligned in accordance with the alignment treatment of the alignment film that is aligned even though the other alignment film is not aligned. Therefore, the liquid crystal display device 10 is formed by combining the substrate 14 having the alignment film treated by the alignment treatment method shown in FIG. 20 and the substrate 12 having the alignment film treated by the alignment treatment method shown in FIG. 21. desirable. However, the substrate 14 having the alignment film treated with the alignment treatment method shown in FIG. 20 and the substrate 12 having the alignment film not subjected to the alignment treatment are combined or the substrate 14 having the alignment layer not subjected to the alignment treatment. Even if the liquid crystal display device 10 is formed by combining the substrate 12 having the alignment film treated by the alignment treatment method shown in 21, the liquid crystal display device 10 having the features shown in FIG. 19 can be obtained.

Similarly, the liquid crystal display device 10 is formed by combining the substrate 14 having the alignment film treated by the alignment treatment method shown in FIG. 22 and the substrate 12 having the alignment film treated by the alignment treatment method shown in FIG. desirable. However, the substrate 14 having the alignment film treated with the alignment treatment method shown in FIG. 22 and the substrate 12 having the alignment film that is not oriented are combined or the substrate 14 having the alignment film that is not oriented. Even if the liquid crystal display device 10 is formed by combining the substrate 12 having the alignment film treated by the alignment treatment method shown in 23, the liquid crystal display device 10 having the features shown in FIG. 19 can be obtained.

Fig. 24 is a diagram showing a mask 80 in the case of performing an alignment process including four domains according to another embodiment of the present invention. 25 is a perspective view showing one optical path changing portion 84 of the mask 80 of FIG. 24, FIG. 26 is a plan view showing the optical path changing portion 84, and FIGS. 27 and 28 are cross-sectional views of the optical path changing portion 84. to be. As in the example of Figs. 14 to 23, the mask 80 of this embodiment is used to irradiate ultraviolet rays to the alignment films 20 and 24 of the substrates 12 and 14 of the liquid crystal display device 10 from the oblique direction. The mask 80 has a body portion 82 and a plurality of optical path changing portions 84. The optical path changing portion 84 is formed as the cavity 82c of the main body portion 82. In the previous embodiment, each cavity 82c has a pair of inclined surfaces 82d and 82e that are inclined to widen with each other in a direction from the first surface 82a to the second surface 82b, but in this embodiment each The cavity 82c has two inclined surfaces.

That is, each cavity 82c is located on both sides of the first vertical surface 82x of the first and second vertical surfaces 82x and 82y that are perpendicular to the first surface 82a and are perpendicular to each other. The first and second inclined surfaces 82d and 82e, which are inclined to widen each other in a direction from 82a to the second surface 82b, on both sides of the second vertical surface 82y, and on the first surface 82a to the second; The third and fourth inclined surfaces 82f and 82g are inclined to widen with each other when viewed in the direction toward the surface 82b. The optical path changing portion 84 is formed by the cavity 82c and the material (air) contained in the cavity 82c. This mask 80 is superimposed on the color filter substrate 14, and the ultraviolet-ray is irradiated in the diagonal direction through the mask 80 on the surface of the alignment film 24 of the color filter substrate 14. In this case, it is better that the alignment film of the TFT substrate 12 is not subjected to alignment treatment.

In the embodiment shown in FIGS. 24-28, the 1st and 2nd inclined surfaces 82d and 82e have the same function as the mask 80 which has the cross-sectional shape of the isosceles triangle shown by previous embodiment. The third and fourth inclined surfaces 82f and 82g have the same function as the mask 80 having the trapezoidal cross-sectional shape shown in the previous embodiment. Ultraviolet rays are irradiated in four directions within one pixel, and different domains of two orientations are formed by ultraviolet rays irradiated obliquely to the alignment film through the first and second inclined surfaces 82d and 82e, and the third and fourth portions. Ultraviolet rays irradiated obliquely to the alignment film through the inclined surfaces 82f and 82g form different domains of the two orientations. Therefore, other domains of four orientations in total are formed, and the display can be seen quite well even when the display is viewed from a considerable time in any direction.

29 and 30 show a modification of the optical path changing portion 84. The light path changing portion 84 in FIG. 26 has a square base shape of a × e (a is the length of the short side, e is the length of the long side), and has a peak 82p corresponding to the trapezoidal upper side. 29 and 30 correspond to the length of the peak 82p in FIG. 26 being zero. Next, the optical path changing portion 84 of Figs. 29 and 30 may be changed to use the optical path changing portion 84 having a square base shape of a × e.

31 shows an example in which the light shielding film 86 is provided in the light path changing portion 84 in FIGS. 25 and 26. The action of the light shielding film 86 is that the ultraviolet light incident on the portion of the alignment film corresponding to one pixel through the first and second inclined surfaces 82d and 82e and the third and fourth inclined surfaces 82f and 82g does not overlap each other. It is to cover a part of the alignment film equivalent to one pixel.

In order for the light shielding film 86 to achieve this effect, it is preferable to satisfy the following relationship. As shown in FIG. 32, both legs of the peak 82p corresponding to the trapezoidal upper side are referred to as points A and B. FIG. The corner portions of the part of the light shielding film 86 which are in the first and second inclined surfaces 82d and 82e and extend in parallel with the peak 82p are referred to as points C, D, E, and F. The points C, D, and E are in the vertical plane passing through the point A perpendicular to the peak 82p, and the points D and F are in the vertical plane passing through the point B perpendicular to the point 82p. The corners of the part of the light shielding film 86 in the third and fourth inclined surfaces 82f and 82g and in the vertical plane including the peak 82p are point G and H. The light shielding film 86 is calculated | required by connecting a line from the point C, D, E, F, G, H to the base-shaped edge part of the square shape of the optical path changing part 84.

In order to find the points C, D, E, F, G and H, it is better to determine the distances d and f. The distance d is the distance in the plane (viewed from above) parallel to the first surface 82a between the peak 82p and the respective points C, D, E, F. The distance f is the distance in which the peak 82p is in the plane (viewed from above) parallel to the first surface 82a of the liver with each point G, H. The distance d is obtained from the relationship of the following equations 6 and 7, and the distance f is obtained from the relationship of the following equations 8 and 9.

Here, the refractive index of the main body portion 82 of the mask 80 is n1, the refractive index of the optical path changing portion 84 is n2, the right angle of the isosceles triangle in the vertical plane is θ ₁ , and the ultraviolet rays to the alignment film and the irradiation angle in the θ _2, the vertical surface of trapezoidal low angle (底角) to θ _3. In addition, the above formulas 1, 2,

In the case of _{θ 1 ≤ 60, n 1 cos} (3θ 1/2) = n 2 sin (θ 2 -θ 1/2)

In the case of _{θ 1 60, n 1 cos (} 3θ 1/2) = n 2 sin (θ 1/2-θ 2)

It is also necessary to establish.

As described above, according to the present invention, since the alignment treatment using ultraviolet irradiation can be performed without causing an orientation defect on the entire substrate, a simple alignment treatment can be performed without a conventional rubbing process. Moreover, by one ultraviolet irradiation, the area | region (domain) which has two orientation directions can be formed in one pixel, and the cost of an apparatus is inexpensive and a manufacturing process can be made quick.

Claims (19)

As a manufacturing method of the liquid crystal display device provided with the pair of board | substrates which oppose at intervals, the alignment film formed in one board | substrate, the alignment film formed in the other board | substrate, and the liquid crystal inserted between the said pair of board | substrates, Forming an alignment film containing a polymer for realizing the vertical alignment property on the substrate, 45 degrees or less with respect to the surface of the alignment film at an exposure amount of 30 to 120mJ / cm ² per 1% content of the polymer for realizing the vertical alignment of the alignment film The polarizing ultraviolet-ray is irradiated to the said oriented film in the diagonal direction, The manufacturing method of the liquid crystal display device characterized by the above-mentioned. The method of claim 1, The exposure amount of the unpolarized ultraviolet-ray which irradiates on the surface of an oriented film is a range of 40-90mJ / cm <^2> , The manufacturing method of the liquid crystal display device characterized by the above-mentioned. The method of claim 1, The exposure amount of the unpolarized ultraviolet-ray which irradiates on the surface of an oriented film is a range of 80-120mJ / cm <^2> , The manufacturing method of the liquid crystal display device characterized by the above-mentioned. The method of claim 1, The exposure amount of an ultraviolet-ray makes a pretilt angle of the liquid crystal with respect to the surface of an oriented film become 89.5 degrees or less, The manufacturing method of the liquid crystal display device characterized by the above-mentioned. The method of claim 1, The wavelength of the ultraviolet-ray irradiated to an oriented film contains the component of 280 nm or less, The manufacturing method of the liquid crystal display device characterized by the above-mentioned. As a manufacturing method of the liquid crystal display device provided with the pair of board | substrates which oppose at intervals, the alignment film formed in one board | substrate, the alignment film formed in the other board | substrate, and the liquid crystal inserted between the said pair of board | substrates, An alignment film is formed on the substrate, and ultraviolet rays are applied to each surface of the alignment film in an oblique direction by using a mask having a main body portion and a plurality of optical path changing portions provided on the main body portion and having a refractive index different from the main body portion. Investigate, Each of the optical path changing portions has a sawtooth shape of an isosceles triangular cross section with the length of the pixel pitch as a base, and a light shielding film is formed at a portion located at the top of the isosceles triangle of the optical path changing portion. The manufacturing method of the liquid crystal display device made into. delete As a manufacturing method of the liquid crystal display device provided with the pair of board | substrates which oppose at intervals, the alignment film formed in one board | substrate, the alignment film formed in the other board | substrate, and the liquid crystal inserted between the said pair of board | substrates, An alignment film is formed on the substrate, and ultraviolet rays are applied to each surface of the alignment film in an oblique direction by using a mask having a main body portion and a plurality of optical path changing portions provided on the main body portion and having a refractive index different from the main body portion. Investigate, Each of the optical path changing portions has a sawtooth-shaped cross-sectional shape of a trapezoidal cross section whose pixel pitch length is the lower side, and a light shielding film is formed at a portion located at the upper side of the trapezoid. . The method according to claim 6 or 8, When the refractive index of the main body portion is n ₁ , the refractive index of the optical path changing portion is n ₂ , the normal angle of the sawtooth-shaped cross-sectional shape is θ ₁ , and the angle of incidence of ultraviolet rays irradiated onto the alignment film through the optical path changing portion is θ ₂ . , In the case of θ ₁ ≤ 60, _{n 1 cos (3θ 1/2} ) = n 2 sin (θ 2 -θ 1/2) Satisfying, In the case of θ ₁ 60, the following formula, _{n 1 cos (3θ 1/2} ) = n 2 sin (θ 1/2-θ 2) The manufacturing method of the liquid crystal display device which satisfy | fills. The method of claim 9, When the refractive index of the main body portion is n ₁ , the refractive index of the optical path changing portion is n ₂ , and the normal angle of the sawtooth-shaped cross-sectional shape is θ ₁ , the following relationship between them cosθ ₁ ≥ n ₂ / n ₁ The manufacturing method of the liquid crystal display device characterized by the above-mentioned. As a manufacturing method of the liquid crystal display device provided with the pair of board | substrates which oppose at intervals, the alignment film formed in one board | substrate, the alignment film formed in the other board | substrate, and the liquid crystal inserted between the said pair of board | substrates, An alignment film is formed on the substrate, and ultraviolet rays are applied to each surface of the alignment film in an oblique direction by using a mask having a main body portion and a plurality of optical path changing portions provided on the main body portion and having a refractive index different from the main body portion. Investigate, The body portion of the mask includes a first flat surface, a second surface opposite the first surface, and a plurality of cavities provided on the second surface, each cavity from the first surface to the second surface. The first and second inclined surfaces inclined to widen with each other in the direction of facing, each cavity having a centerline between the first inclined surface and the second inclined surfaces, the optical path changing portion being in the cavity and the material contained within the cavity. Formed by Ultraviolet light incident on the main body portion from the first surface and transmitted through the first inclined surface is obliquely radiated to the alignment layer in a first direction, and ultraviolet light transmitted through the second inclined surface is different from the first direction on the alignment layer. The manufacturing method of the liquid crystal display device characterized by irradiating obliquely in the 2nd direction opposite. A pair of substrates opposed to each other, an alignment film formed on one substrate, an alignment film formed on the other substrate, a plurality of bus lines provided on one substrate, and a liquid crystal inserted between the pair of substrates As a manufacturing method of one liquid crystal display device, An alignment film is formed on the substrate, A mask having a main body portion and a plurality of optical path changing portions provided in the main body portion corresponding to the pixel pitch, wherein the main body portion of the mask comprises a first flat surface, a second surface opposite to the first surface, A plurality of cavities provided on the second surface, each cavity being on both sides of a vertical plane perpendicular to the first surface and inclined to widen with one another in a direction from the first surface to the second surface; Has a first and second inclined surfaces, the optical path changing portion is formed by the cavity and a material contained in the cavity, For one substrate having the bus line, the mask is overlapped with the substrate so that a vertical plane between the first inclined plane and the second inclined plane is on the bus line, The ultraviolet-ray is irradiated to the surface of the said oriented film of the said board | substrate in the diagonal direction through the said mask, The manufacturing method of the liquid crystal display device characterized by the above-mentioned. A pair of substrates opposed to each other, an alignment film formed on one substrate, an alignment film formed on the other substrate, a plurality of bus lines provided on one substrate, and a liquid crystal inserted between the pair of substrates As a liquid crystal display manufacturing method, An alignment film is formed on the substrate, A mask having a main body portion and a plurality of optical path changing portions provided in the main body portion corresponding to the pixel pitch, wherein the main body portion of the mask comprises a first flat surface, a second surface opposite to the first surface, A plurality of cavities provided on the second surface, each cavity being on both sides of a vertical plane perpendicular to the first surface and inclined to widen with one another in a direction from the first surface to the second surface; Has a first and second inclined surfaces, the optical path changing portion is formed by the cavity and a material contained in the cavity, For the other substrate without the bus line, the mask is placed so that the end on the second surface of the first inclined surface and the end on the second surface of the second inclined surface are on a line corresponding to the bus line. Overlapping the substrate, The ultraviolet-ray is irradiated to the surface of the said oriented film of the said board | substrate in the diagonal direction through the said mask, The manufacturing method of the liquid crystal display device characterized by the above-mentioned. The method according to claim 12 or 13, The cavity has a sawtooth shape of an isosceles triangle cross section, and a light shielding film is formed at a portion located at the top of the isosceles triangle. The method according to claim 12 or 13, The cavity has a sawtooth shape having a trapezoidal cross section, and a light shielding film is formed at a portion located at an upper side of the trapezoid. A pair of substrates opposed to each other, an alignment film formed on one substrate, an alignment film formed on the other substrate, a plurality of bus lines provided on one substrate, and a liquid crystal inserted between the pair of substrates As a liquid crystal display manufacturing method, An alignment film is formed on the substrate, A mask having a main body portion and a plurality of optical path changing portions provided in the main body portion corresponding to the pixel pitch, wherein the main body portion of the mask comprises a first flat surface, a second surface opposite to the first surface, A plurality of cavities provided on the second surface, each cavity being on both sides of a first vertical plane of the first and second vertical planes perpendicular to each other and perpendicular to the first surface; First and second inclined surfaces that are inclined to widen with each other in a direction toward the second surface, and third and second sides that are inclined to widen in a direction from the first surface to the second surface, on both sides of the second vertical surface; Has a fourth inclined surface, the optical path changing portion is formed by the cavity and a material contained in the cavity, Superimposing the mask on the substrate, The ultraviolet-ray is irradiated to the surface of the said oriented film of the said board | substrate in the diagonal direction through the said mask, The manufacturing method of the liquid crystal display device characterized by the above-mentioned. The method of claim 16, The cavity has at least one of a sawtooth shape of an isosceles triangle cross section and a sawtooth shape of a trapezoidal cross section. The method of claim 16, Wherein the first and second inclined surfaces are inclined planes of an isosceles triangle, and the third and fourth inclined surfaces are trapezoidal inclined surfaces. As a manufacturing method of the liquid crystal display device provided with the pair of board | substrates which oppose at intervals, the alignment film formed in one board | substrate, the alignment film formed in the other board | substrate, and the liquid crystal inserted between the said pair of board | substrates, An alignment film is formed on the substrate, and ultraviolet rays are applied to each surface of the alignment film in an oblique direction by using a mask having a main body portion and a plurality of optical path changing portions provided on the main body portion and having a refractive index different from the main body portion. Investigate, And the mask is arranged such that incident light is reflected by the surface of the optical path changing portion and is incident on another optical path changing portion.