KR101993342B1 - Liquid Crystal Display Device and Method Of Fabricating The Same - Google Patents

Abstract

It is an object of the present invention to provide a liquid crystal display device capable of improving the light transmittance and the contrast ratio and improving the responsiveness at the time of voltage off.
A liquid crystal display device according to the present invention comprises a first substrate, a second substrate facing the first substrate, a liquid crystal layer interposed between the first substrate and the second substrate, and a liquid crystal layer interposed between the first substrate and the liquid crystal layer side A plurality of electrodes formed on the first substrate and the second substrate so as to be capable of forming an electric field in a horizontal direction with respect to the substrate surfaces of the first substrate and the second substrate; a first alignment film formed directly on the plurality of electrodes; And a third alignment film formed on the liquid crystal layer side of the second substrate, wherein the anchoring energy of the first alignment film is smaller than the anchoring energy of the second and third alignment films, and the second alignment film is formed on the first alignment film The affinity with the region on the first substrate between the plurality of electrodes is higher.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device,

The present invention relates to a liquid crystal display device and a manufacturing method of the liquid crystal display device.

As a display method of a liquid crystal panel, there is known an IPS (In-Plane Switching) method in which display is controlled by applying a voltage to electrodes formed on a glass substrate to form an electric field in a horizontal direction with respect to the substrate surface. In the IPS system, the outer tube length (refractive index ellipsoid) of the liquid crystal molecules is substantially constant regardless of the viewing angle direction of the liquid crystal panel, so that the viewing angle characteristic is excellent.

In the liquid crystal panel, the alignment direction of the liquid crystal molecules is forced so that the liquid crystal molecules are oriented in a predetermined direction in a state in which no electric field is applied. As a method for forcing the alignment direction of the liquid crystal molecules in the IPS liquid crystal panel, a rubbing method, a photo alignment method, and the like are known. In the rubbing method, an alignment film made of polyimide or the like is formed on a substrate, and the surface of the alignment film is rubbed with a cloth. In the photo alignment method, ultraviolet rays, which are linearly polarized light, are irradiated onto the surface of an alignment film made of a polyimide film or the like to have anisotropy on the surface of the alignment film. In a conventional IPS liquid crystal panel, an alignment film is formed on each inner side of a pair of substrates holding a liquid crystal composition (Patent Document 1).

However, in the conventional IPS liquid crystal panel as described in Patent Document 1, a slight deviation may occur in the alignment direction of the alignment film formed on each pair of substrates sandwiching the liquid crystal layer. The misalignment of the alignment direction of the alignment film is caused, for example, by the deviation during the rubbing process and the misalignment between the substrates during the adhesion. If there is a deviation in the alignment direction, a minute twist occurs in the liquid crystal molecules of the liquid crystal layer even when the voltage is off. The minute twist of the liquid crystal molecules at the time of power-off causes light scattering in the black display, resulting in a decrease in the contrast ratio. Further, in the conventional IPS liquid crystal panel, an electric field which is perpendicular to the substrate surface is formed on the comb electrodes for forming a transverse electric field in the horizontal direction with respect to the substrate surface. Therefore, the liquid crystal molecules are not sufficiently twisted in the transverse direction, and as a result, light transmission on the comb electrode becomes difficult, and the light transmittance of the liquid crystal panel is lowered. That is, the aperture ratio of the liquid crystal panel is lowered.

Therefore, Patent Document 2 proposes a liquid crystal panel in which a weak anchoring orientation film is formed on a one-sided substrate disposed opposite to the other and a strong anchoring orientation film is formed on the other substrate. In the liquid crystal panel described in Patent Document 2, the weak anchoring orientation film has a binding force for restricting the orientation direction of the liquid crystal molecules when the electric field is applied is smaller than that of the strong anchoring orientation film. With such a configuration, in the liquid crystal panel described in Patent Document 2, display with high light transmittance is realized.

Patent Document 1: Japanese Patent Publication No. 2940354 Patent Document 2: JP-A-2016-170389

However, in the liquid crystal panel described in Patent Document 2, since the anchoring energy is reduced over the entire weak anchoring orientation film formed on the one-sided substrate arranged opposite to each other, the restoring force at the time of voltage off becomes small. Therefore, the response at the time of voltage off is lowered and the response time (turn-off time) τ _off at the time of voltage _off becomes longer.

An object of the present invention is to provide a liquid crystal display device capable of improving the light transmittance and the contrast ratio and improving the responsiveness at the time of voltage off. It is also an object of the present invention to provide a liquid crystal display device manufacturing method which can easily manufacture such a liquid crystal display device without complicating the process.

According to one aspect of the present invention, there is provided a liquid crystal display device comprising a first substrate, a second substrate facing the first substrate, a liquid crystal layer interposed between the first substrate and the second substrate, A plurality of electrodes formed on the side of the layer side and configured to be capable of forming an electric field in a plane horizontal to the first substrate; a first alignment film formed directly on the plurality of electrodes; And a third alignment film formed on the liquid crystal layer side of the second substrate, wherein the anchoring energy of the first alignment film is smaller than the anchoring energy of the second and third alignment films, And the second alignment layer has a higher affinity with a region on the first substrate between the plurality of electrodes than the first alignment layer.

According to another aspect of the present invention, there is provided a liquid crystal display device comprising a first substrate, a second substrate facing the first substrate, a liquid crystal layer interposed between the first substrate and the second substrate, A plurality of electrodes formed on a side of the first substrate and configured to be capable of forming an electric field in a plane horizontal to the first substrate; a first alignment film formed directly on the plurality of electrodes; And a third alignment film formed on the liquid crystal layer side of the second substrate, wherein the anchoring energy of the first alignment film is smaller than the anchoring energy of the second and third alignment films, The method comprising the steps of: forming the plurality of electrodes on the first substrate; forming a plurality of electrodes on the first substrate, A step of sandwiching the liquid crystal layer in which the photopolymerizable material is mixed in the liquid crystal material between the first substrate and the second substrate on which the third alignment film is formed; The second alignment film comprising the polymer phase separation of the photopolymerizable material in the liquid crystal layer in the liquid crystal layer by light irradiation so that the second alignment film comprising the polymerized phase separation of the photopolymerizable material is formed on the first substrate between the plurality of electrodes And a step of forming a liquid crystal layer on the substrate.

According to the present invention, in the liquid crystal display device, the response at the time of voltage off can be improved while the light transmittance is improved. Further, according to the present invention, it is possible to easily manufacture a liquid crystal display device capable of improving the light transmittance and the responsiveness at the time of voltage off without complicating the process.

Fig. 1 is a cross-sectional view showing the structure of a liquid crystal display device when liquid crystals having positive (positive or negative) dielectric anisotropy are used according to an embodiment of the present invention.
FIG. 2 is a graph showing the relationship between the voltage off state of the liquid crystal display device and the alignment state of the liquid crystal molecules in the liquid crystal layer at the time of voltage ON when the liquid crystal having a positive (positive) dielectric anisotropy according to an embodiment of the present invention is used Fig.
3 is a process sectional view (1) showing a method of manufacturing a liquid crystal display device according to an embodiment of the present invention.
4 is a sectional view (2) of a process showing a manufacturing method of a liquid crystal display device according to an embodiment of the present invention.
5 is a sectional view (3) of a process showing a method for manufacturing a liquid crystal display device according to an embodiment of the present invention.
6 is a cross-sectional view (4) of a process for manufacturing a liquid crystal display device according to an embodiment of the present invention.
Fig. 7 is a cross-sectional view showing the structure of a liquid crystal display device in the case of using positive (positive, positive) dielectric anisotropy according to a modification of the embodiment of the present invention.

<Embodiment>

A liquid crystal display device and a manufacturing method of a liquid crystal display device according to an embodiment of the present invention will be described with reference to Figs. 1 to 6. Fig.

First, the structure of the liquid crystal display device according to the present embodiment will be described with reference to Figs. 1 and 2. Fig. 1 is a cross-sectional view showing the structure of a liquid crystal display device according to the present embodiment. Fig. 2 is a cross-sectional view schematically showing the alignment state of the liquid crystal molecules in the liquid crystal layer at the time of voltage off and voltage on the liquid crystal display device according to the present embodiment. 1 and 2 illustrate a case where a liquid crystal layer is constituted by using a positive type liquid crystal material.

The liquid crystal display device according to the present embodiment controls an image by forming an electric field in a horizontal direction with the IPS liquid crystal panel. As shown in Fig. 1, the liquid crystal display device 10 according to the present embodiment has an IPS-system liquid crystal panel 12 and a backlight unit 14. Fig.

The liquid crystal panel 12 has a pair of substrates 16 and 18 arranged to face each other. The substrates 16 and 18 are disposed so as to face each other with the liquid crystal layer 20 interposed therebetween. The substrates 16 and 18 are attached to each other with a predetermined gap therebetween by a sealing material 22 disposed around the periphery of the display region including pixels. The liquid crystal constituting the liquid crystal layer 20 is sealed between the substrates 16 and 18 by the sealing material 22. [ The substrates 16 and 18 are not particularly limited as long as they are each a translucent substrate, and for example, they are glass substrates. As the liquid crystal material constituting the liquid crystal layer 20, for example, a nematic liquid crystal material having a positive dielectric anisotropy can be used, and a nematic liquid crystal material having a negative dielectric anisotropy can also be used . 1 schematically shows the liquid crystal molecules 202 of the liquid crystal layer 20 when voltage is applied to the linear electrode 24 to be described later.

For example, the substrate 16 is a TFT substrate on which a thin film transistor (TFT) for switching pixels, a gate line, and a source line are formed. The substrate 18 is a CF substrate on which a color filter (CF) is formed.

A plurality of linear electrodes 24 are formed on the surface of the backlight unit 14 side substrate 16 on the liquid crystal layer 20 side of the substrates 16 and 18. The plurality of linear electrodes 24 are arranged parallel to each other at a predetermined interval to form a comb electrode. More specifically, the plurality of linear electrodes 24 constitute a comb-shaped pixel electrode and a comb-shaped common electrode. Fig. 1 shows a cross section orthogonal to the longitudinal direction of the linear electrode 24. Fig. The plurality of linear electrodes 24 are capable of forming an electric field in a horizontal direction with respect to the substrate surface of the liquid crystal layer 20 and the substrate 16, that is, capable of forming an electric field in a plane horizontal to the substrate 16.

The linear electrode 24 is a transparent electrode made of ITO (Indium Tin Oxide) having a high light transmittance T of, for example, 88%. The main material of the linear electrode 24 is not limited to ITO. The linear electrode 24 is preferably a transparent conductive film or a conductive film having a high light transmittance. As the main material of the linear electrode 24, for example, IZO (Indium Zinc Oxide, T = 85%) and AZO (Aluminum doped Zinc Oxide, T = 92%) can be used instead of ITO. Also, GZO (Gallium doped Zinc Oxide, T = 92%) and ATO (Antimony Tin Oxide, T = 87%) can be used.

A control unit (not shown) of the liquid crystal display device 10 applies a voltage to the linear electrodes 24 of the substrate 16 to form an electric field in the horizontal direction with the substrate surface of the substrate 16, The display of the liquid crystal panel 12 is controlled by rotating the liquid crystal molecules.

In the liquid crystal panel 12, polarizing plates 28 and 30 are provided on the outer sides of the substrates 16 and 18, respectively. The polarization axis directions of the polarizers 28 and 30 are set so that light illuminated from the backlight unit 14 passes when a voltage is applied to the linear electrodes 24. [ For example, the directions of the polarization axes of the polarizers 28 and 30 are orthogonal to each other. The direction of the polarization axis of the polarizers 28 and 30 may be set such that the light illuminated from the backlight unit 14 is blocked when a voltage is applied to the linear electrodes 24. [

On the surface of the substrate 18 on the side of the liquid crystal layer 20, a strong anchoring film 32 is formed as an alignment film over the entire surface of the liquid crystal layer 20. The steel anchoring film 32 is made of, for example, a polyimide film subjected to orientation treatment by a rubbing method. The steel anchoring film 32 coincides with the liquid crystal molecule orientation of the liquid crystal layer 20 when the voltage is turned off with respect to the linear electrode 24 together with the steel anchoring film 36 on the side of the substrate 16 to be described later. The alignment direction of the liquid crystal molecules of the liquid crystal layer 20 when the voltage is off is a direction that is a predetermined angle with respect to the longitudinal direction of the linear electrode 24 or the longitudinal direction of the linear electrode 24, for example.

On the other hand, on the plurality of linear electrodes 24 formed on the substrate 16 between the substrate 16 and the liquid crystal layer 20, a weak anchoring film 34 is formed as an orientation film. The weak anchoring film 34 is formed directly on the plurality of linear electrodes 24. The weak anchoring film 34 is an alignment film having a lower anchoring energy than the steel anchoring film 32 on the substrate 18 side and the steel anchoring film 36 described below. The anchoring referred to in the steel anchoring films 32 and 36 and the weak anchoring film 34 relates to anchoring in the azimuth angle direction and the magnitude relation of the anchoring energies is a magnitude relation with respect to the anchoring energy in the azimuth angle direction. The weak anchoring film 34 is formed directly on each of a plurality of linear electrodes 24 arranged in parallel to each other. The weak anchoring film 34 is made of a resin film, and more specifically, it is made of the exposed photosensitive resin film 56a as described later. The weak anchoring film 34 is sandwiched between a plurality of linear electrodes 24 on a region on the substrate 16 and more specifically a base film 38 to be described below and a strong anchoring film 36 and a steel anchoring film And has a low affinity with the material constituting the film (36).

A strong anchoring film 36 is formed as an orientation film on the substrate 16 between the linear electrodes 24 on which the weakly anchoring film 34 is formed. A base film 38 is formed between the steel anchoring film 36 and the substrate 16. The UV polymerizable monomer constituting the steel anchoring film 36 and the steel anchoring film 36 has a higher affinity with the weak anchoring film 34 than the base of the region on the substrate 16 between the plurality of linear electrodes 24 And has a high affinity with the membrane (38).

The base film 38 is made of a resin film, and more specifically, it is made of a photosensitive resin film 56 which is not exposed as described later. The steel anchoring film 36 is formed directly on the base film 38 so as to be in contact with the base film 38. [ The anchoring energy of the steel anchoring film 36 is, for example, about the same as the anchoring energy of the steel anchoring film 32.

The steel anchoring film 36 is composed of a polymerized phase separation membrane obtained by polymerizing and phase-separating a UV polymerizable monomer which is a photopolymerizable monomer mixed in a liquid crystal material constituting the liquid crystal layer 20 as described later. On the substrate 16 between the plurality of linear electrodes 24, the base film 38 is formed as described above. The strong anchoring film 36 and the UV polymerizable monomer serving as the material thereof have a higher affinity with the base film 38 than the affinity with the weaker anchoring film 34. Therefore, the steel anchoring film 36 is selectively formed on the base film 38, and is not formed on the weak anchoring film 34.

The polymerizable liquid crystal, which is the UV polymerizable monomer constituting the steel anchoring film 36, is mixed in the liquid crystal material and is injected into the cell, and then the alignment regulating force of the steel anchoring film 32 on the substrate 18 side, The homogeneous orientation is performed in a certain direction.

When the cell is irradiated with UV light, the polymerizable liquid crystal initiates polymerization and begins to phase-separate from the liquid crystal at a stage when the polymerization degree reaches a certain degree. The phase-separated polymerizable liquid crystal (liquid crystal polymer) is preferentially discharged at the liquid crystal / base film 38 interface in order to minimize the increase in energy due to the orientation disorder of the liquid crystal layer. At this time, the liquid crystal polymer which is a polymer of the polymerizable liquid crystal is phase-separated on the interface of the liquid crystal / base film 38 while maintaining the same alignment direction as that of the surrounding liquid crystal. On the base film 38, 32 are formed in the same direction as that of the anchoring film 36.

As described above, on the substrate 18 side, a strong anchoring film 32 is formed as an alignment film. On the other hand, on the side of the substrate 16, a weak anchoring film 34 is formed as an alignment film immediately above each of the plurality of linear electrodes 24. On the substrate 16 side, a strong anchoring film 36 is formed as an orientation film on the substrate 16 between the plurality of linear electrodes 24.

The anchoring energy of the weak anchoring film 34 is smaller than the anchoring energy of the strong anchoring films 32 and 36, preferably 10 ^-6 J / m ² or less. The anchoring energy of the steel anchoring films 32 and 36 is larger than the anchoring energy of the weak anchoring film 34, and is preferably 10 ^-4 J / m ² or more.

A color filter (40) is provided between the substrate (18) and the steel anchoring film (32). The color filter 40 is composed of three primary color patterns of R (red) / G (green) / B (blue) as color resist, a black matrix, / B Pass the light in the wavelength region of the three primary colors.

The backlight unit 14 is a lighting device that emits light for illuminating the liquid crystal panel 12. [ The backlight unit 14 may be an edge light type or a direct lower type. Further, a light diffusion sheet and a prism sheet may be disposed between the backlight unit 14 and the liquid crystal panel 12.

The liquid crystal display device 10 according to the present embodiment includes an IPS system for controlling the display by forming a transverse electric field in the horizontal direction with the substrate surface of the substrate 16 and rotating the liquid crystal molecules in the plane of the liquid crystal layer 20, . However, if a strong anchoring film is formed on the entire surface of the substrate 16 side just above the linear electrode 24 as in the conventional configuration described in the above-mentioned Patent Document 1, The liquid crystal molecules immediately above the liquid crystal molecules can not be sufficiently rotated. This is because the component horizontal to the substrate surface of the electric field just above the linear electrode 24 for forming an electric field is not large enough to overcome the constraint of the strong anchoring film and rotate the liquid crystal molecules. Therefore, in this case, the light transmittance in the white display is lowered.

On the other hand, if a weak anchoring film is formed on the entire surface of the substrate 16 side as in the conventional structure described in the above-mentioned Patent Document 2, the alignment control force on the substrate 16 side is weakened to achieve a high light transmittance So that a sufficient light transmittance in white display can be secured. However, in this case, since the restoring force of the liquid crystal molecules at the time of voltage off to the linear electrode 24 is lowered, the response at the time of voltage off decreases and the response time? Off at the time of voltage _off becomes longer.

In the liquid crystal display device 10 according to the present embodiment, a weak anchoring film 34 having a relatively small anchoring energy is formed directly on each of the plurality of linear electrodes 24, compared with the conventional configuration. On the linear electrode 24 on which the weak anchoring film 34 is formed, the alignment restraining force is weaker than the region where the strong anchoring film 36 is formed. Therefore, in the liquid crystal display device 10 according to the present embodiment, even when the horizontal component of the electric field is small, since the liquid crystal molecules directly above the linear electrode 24 rotate, a sufficient light transmittance . Thus, the liquid crystal display device 10 according to the present embodiment can improve the light transmittance.

2 (a) schematically shows the alignment state of the liquid crystal molecules 202 in the liquid crystal layer 20 of the liquid crystal display device 10 when the voltage is applied to the linear electrode 24. As shown in Fig. 2 (a), the liquid crystal molecules 202 are oriented along the direction from the back surface of the paper of Fig. 2 (a) to the surface of the paper.

2 (b) schematically shows the alignment state of the liquid crystal molecules 202 in the liquid crystal layer 20 of the liquid crystal display device 10 when the voltage to the linear electrode 24 is turned on . 2 (b), since the liquid crystal molecule 202 has the weak anchoring film 34 formed just above the linear electrode 24, the liquid crystal molecules 202 are sufficiently rotated within the plane of the liquid crystal layer 20 . Therefore, in the liquid crystal display device 10, the light transmittance at the time of voltage ON can be improved.

The linear anisotropic film 34 is formed on the upper surface of the linear electrode 24. This is because the alignment direction of the liquid crystal molecules on the substrate 16 side and the alignment direction of the liquid crystal molecules on the substrate 18 side The minute twist of the liquid crystal molecules can be suppressed when the voltage is turned off. As a result, the black luminance can be reduced, and the contrast ratio can be improved in addition to the improvement in the light transmittance.

Furthermore, in the liquid crystal display device 10 according to the present embodiment, the steel anchoring film 36 is formed on the substrate 16 between the linear electrodes 24. Since the steel anchoring film 36 having a relatively large anchoring energy is formed in a region other than just above each of the plurality of linear electrodes 24 as described above, The restoring force is hardly lowered. Therefore, the liquid crystal display device 10 according to the present embodiment is superior in the responsiveness of the liquid crystal display at the time of voltage off compared with the conventional configuration in which the weakened anchoring film is formed on the entire surface of the substrate 16 side as described in Patent Document 2 And the response time τ _off at the time of voltage off can be shortened. The steel anchoring film 36 formed between the linear electrodes 24 has the alignment regulating force in the same direction as the steel anchoring film 32 on the substrate 18, It is possible to suppress the fine twist of the liquid crystal molecules when the voltage is turned off due to the misalignment of the alignment direction of the liquid crystal molecules on the liquid crystal layer 18 side. As a result, the black luminance can be reduced and the contrast ratio can be improved.

As described later, the strong anchoring film 36 can be formed by polymerization phase separation of UV-polymerizable monomers mixed in the liquid crystal material constituting the liquid crystal layer 20 without using a special method such as an inkjet method. Therefore, the liquid crystal display device 10 according to the present embodiment can be easily manufactured without complicating the process.

In this way, the liquid crystal display device 10 according to the present embodiment can improve the response at the time of voltage off while improving the light transmittance and the contrast ratio, so that both brightness and responsiveness of the liquid crystal display can be achieved.

Next, a method of manufacturing the liquid crystal display device according to the present embodiment will be described with reference to Figs. 3 to 6. Fig. Figs. 3 to 6 are process sectional views showing a manufacturing method of the liquid crystal display device according to the present embodiment.

First, as a comb electrode for forming an electric field (transverse electric field) in a horizontal direction with the substrate surface of the substrate 16 on the surface of the substrate 16 on the side of the liquid crystal layer 20, Thereby forming a film 50 (Fig. 3 (a)). In the substrate 16, a TFT, a gate line, a source line, and the like for switching pixels are formed.

Subsequently, a negative photoresist material is applied on the transparent conductive film 50 by, for example, a spin coating method, and a pre-baking is performed to form a photoresist film 52 (FIG. 3 (b) ).

Subsequently, the mask pattern of the mask 54 is exposed to the photoresist film 52 by using the mask 54 (Fig. 3 (c)). The mask 54 has a pattern 542 of a plurality of linear electrodes 24 as a mask pattern. As the exposure light, it is possible to select ultraviolet light or the like in accordance with the type of the photoresist film 52. The pattern 542 is exposed to the photoresist film 52a in the photoresist film 52 by the exposure using the mask 54 in this manner.

Subsequently, the photoresist film 52 is developed, and the unexposed photoresist film 52 is removed, followed by post bake. Thereby, a photoresist film 52a is formed on the transparent conductive film 50 (Fig. 4 (a)).

Then, the transparent conductive film 50 is etched and patterned by, for example, wet etching using the photoresist film 52a as a mask. Thereby, a plurality of linear electrodes 24 made of the transparent conductive film 50 are formed (Fig. 4 (b)).

Subsequently, the photoresist film 52a on the linear electrode 24 is removed by, for example, dipping in a peeling solution (Fig. 4 (c)).

Subsequently, a photosensitive resin material is coated on the substrate 16 between the linear electrode 24 and the linear electrode 24 by, for example, spin coating, and a pre-heat treatment is performed to form the photosensitive resin film 56 (Fig. 5 (a)). The photosensitive resin 56 is designed so that the affinity with the UV polymerizable monomer which is the material constituting the strong anchoring film 36 and the strong anchoring film 36 is lowered while the anchoring energy of the photosensitive resin 56 is lowered to become a weak anchoring material .

A photosensitive resin film (not shown) on the linear electrode 24 in the photosensitive resin film 56 is formed by using the same mask 54 as the mask 54 used for exposure of the photoresist film 52 shown in Fig. 56a are selectively exposed (Fig. 5 (b)). At this time, the photosensitive resin film 56 on the substrate 16 between the linear electrodes 24 remains unexposed.

The photosensitive resin film 56a on the linear electrode 24 is irradiated with UV light so that the anchoring energy is lowered to become a weak anchoring material while the UV anchoring monomer 36, The affinity with the substrate is deteriorated. As a result, the unexposed photosensitive resin film 56 on the substrate 16 between the plurality of linear electrodes 24 is sandwiched by the stronger anchoring film 36 and the thicker anchoring film 56 than the photosensitive resin film 56a on the linear electrode 24, The affinity with the UV polymerizable monomer which is the material constituting the photopolymerization initiator 36 is enhanced.

In this way, a weak anchoring film 34 composed of the exposed photosensitive resin film 56a is formed directly on each of the plurality of linear electrodes 24, and on the substrate 16 between the linear electrodes 24, A base film 38 made of a non-photosensitive resin film 56 is formed (Fig. 5 (c)). The base film 38 is formed on the surface of the weakening anchoring film 34 on the exposed linear electrode 24 as shown in Fig. The affinity with the maleic monomer was increased. That is, the weakly anchoring film 34 has lower affinity with the steel anchoring film 36 and the material constituting it than the base film 38.

On the other hand, a color filter 40 is formed on the substrate 18. Subsequently, a polyimide film is formed on the color filter 40. Subsequently, the polyimide film is subjected to alignment treatment by, for example, a rubbing method, a photo alignment method, or the like. Thus, a strong anchoring film 32 made of a polyimide film is formed on the color filter 40 (Fig. 5 (c)).

Then, the liquid crystal layer 20 is sealed between the substrates 16 and 18 by the ODF (One Drop Fill) method as described below, and the strong anchoring film 36 is selectively formed on the base film 38.

A sealing material 22 made of an ultraviolet curable resin is applied onto one of the substrates 16 and 18 in the peripheral portion of the display region. Subsequently, a liquid crystal material is dropped onto one of the substrates 16 and 18 to which the sealing material 22 is applied. A UV polymerizable monomer, which is a material constituting the steel anchoring film 36, is mixed in the liquid crystal material to be dropped therein. Subsequently, one of the substrates 16 and 18 on which the liquid crystal material is dropped and the other of the substrates 16 and 18 are bonded together by the sealing material 22 (Fig. 6 (a)). Between the substrates 16 and 18, a liquid crystal layer 20 made of a liquid crystal material is formed. In the liquid crystal layer 20, the UV polymerizable monomer 362 is included together with the liquid crystal molecules 202.

6 (a) in which the substrate 16 and the substrate 18 are bonded together, the liquid crystal molecules 202 of the liquid crystal layer 20 are aligned with the orientation of the steel anchoring film 32 on the substrate 18 And is uniaxially oriented along the longitudinal direction of the linear electrode 24 by the restricting force. The UV polymerizable monomer 362 mixed in the liquid crystal material is also oriented along the alignment direction in which the liquid crystal molecules 202 are uniaxially oriented.

Subsequently, the sealant 22 is cured by irradiating ultraviolet light. Further, by irradiating ultraviolet rays for curing the sealing material 22, the UV polymerizable monomer 362 as a photopolymerizable material in the liquid crystal layer 20 is polymerized and phase-separated. Herein, the base film 38 has a higher affinity with the UV polymerizable monomer 362 than the weakly anchoring film 34. The polymerized phase-separated polymer of the UV polymerizable monomer 362 is thus adhered to the base film 38 between the plurality of linear electrodes 24 while closely adhering to the weaker anchoring film 34 on the plurality of linear electrodes 24. [ It does not. Further, the UV polymerizable monomer 362 is polymerized and phase-separated in a state in which the liquid crystal molecules 202 are oriented along the alignment direction in which the liquid crystal molecules 202 are uniaxially oriented. Therefore, the polymer in which the UV-polymerizable monomer 362 is polymerized and phase-separated does not require orientation treatment by the rubbing method, and has a strong alignment restricting force against the liquid crystal molecules 202. A strong anchoring film 36 in which the UV polymerizable monomer 362 in the liquid crystal layer 20 is polymerized and phase-separated by ultraviolet irradiation is selectively formed on the base film 38 (Fig. 6B) . The ultraviolet ray irradiation for polymerizing and phase-separating the UV polymerizable monomer 362 may be performed separately from the ultraviolet ray irradiation for curing the sealing material 22.

Thus, the substrate 16 and the substrate 18 are adhered to each other with the liquid crystal layer 20 made of a liquid crystal material interposed therebetween and the liquid crystal layer 20 is sealed between the substrates 16 and 18 by the ODF method, An anchoring film 36 is selectively formed on the base film 38.

Then, the polarizers 28 and 30 are attached to the substrates 16 and 18, the driver IC is mounted, and the backlight unit 14 is disposed according to a conventional process. Thus, the liquid crystal display device 10 according to the present embodiment shown in Fig. 1 is manufactured.

As described above, in the present embodiment, the strong anchoring film 36 is selectively formed on the base film 38 between the plurality of linear electrodes 24 by the polymerization phase separation of the UV polymerizable monomer 362. Therefore, in the present embodiment, the steel anchoring film 36 can be selectively formed between the plurality of linear electrodes 24 formed immediately above the weak anchoring film 34, without using a special method such as the ink jet method. Therefore, according to the present embodiment, it is possible to easily manufacture the liquid crystal display device 10 shown in Fig. 1 without complicating the process.

As described above, according to the present embodiment, in the liquid crystal display device 10, it is possible to improve the light transmittance and the contrast ratio and improve the responsiveness in the voltage off state. According to the present embodiment, the liquid crystal display device 10 that can improve the light transmittance and the contrast ratio and improve the responsiveness at the time of voltage off can be easily manufactured without complicating the process.

<Modifications>

Next, a liquid crystal display according to a modification of the embodiment will be described with reference to FIG. 7 is a cross-sectional view showing a structure of a liquid crystal display device according to a modification of the embodiment.

In the liquid crystal display device 10 shown in Fig. 1, a strong anchoring film 36 is selectively formed on the base film 38 between the linear electrodes 24, but the present invention is not limited thereto. The steel anchoring film 36 may be selectively formed on the substrate 16 between the plurality of linear electrodes 24 directly without interposing the base film 38. [

7, the strong anchoring film 36 is selectively formed on the substrate 16 between the linear electrodes 24 without interposing the base film 38. In the liquid crystal display device 100 according to the modification shown in Fig. 7, .

For example, the inorganic insulating film and the organic insulating film formed between the linear electrodes 24 have higher affinity with the UV polymerizable monomer 362 that is the material of the strong anchoring film 36 than the weaker anchoring film 34 . Therefore, even when the base film 38 is not formed in the state shown in Fig. 6A and the substrate 16 is exposed between the plurality of linear electrodes 24, The steel anchoring film 36 can be selectively formed. That is, the polymer of the UV-polymerizable monomer 362 polymerized by ultraviolet irradiation is in close contact with the inorganic insulating film between the plurality of linear electrodes 24 and the organic insulating film while the polymer film of the weaker anchoring film 34 on the plurality of linear electrodes 24 ). In this way, a strong anchoring film 36 in which the UV polymerizable monomer 362 in the liquid crystal layer 20 is polymerized and phase-separated by ultraviolet irradiation is selectively applied onto the substrate 16 between the plurality of linear electrodes 24 Directly formed.

The substrate 16 in which the base film 38 is not formed between the linear electrodes 24 and the weak anchoring film 34 is formed just above the linear electrodes 24 is prepared in the following manner can do. That is, after the linear electrode 24 is formed as shown in FIG. 4 (c), the weak anchoring film 34 can be selectively formed on the linear electrode 24 by, for example, an inkjet method. A negative resist film is used as the photosensitive resin film 56 and the unexposed photosensitive resin film 56 between the linear electrodes 24 after exposure of the photosensitive resin film 56a as shown in FIG. ) May be removed by development. The method of forming the weak anchoring film 34 on the linear electrode 24 is not limited to this.

Then, the liquid crystal display device 100 shown in Fig. 7 can be manufactured by performing the same processes as those of Figs. 5 (c), 6 (a) and 6 (b).

&Lt; Evaluation result >

Next, evaluation results of the liquid crystal display device according to the present embodiment will be described.

Simulations were performed for each of the liquid crystal display devices according to Example 1 and Comparative Examples 1 and 2 to calculate the maximum transmittance T _max , the contrast ratio CR, and the response time τ _off at the time of voltage off. The cell configuration of the liquid crystal display device according to each of the embodiments and the comparative example is as follows.

The cell configuration of the first embodiment is such that a weak anchoring film 34 is provided just above the linear electrode 24 on the substrate 16 side corresponding to the cell of the liquid crystal display device 10 shown in Fig. And a steel anchoring film 36 is provided between the linear electrodes 24. The comb electrodes were formed by arranging the linear electrodes 24 having a width of 3 m at intervals of 10 탆.

The cell configuration of Comparative Example 1 is similar to that of the cell of the liquid crystal display device 10 shown in Fig. 1 except that a weak anchoring film 34 and a strong anchoring film 36 are provided on the substrate 16 side, 16) is provided on the front surface of the steel anchoring membrane.

The structure of Comparative Example 2 is similar to the structure of Comparative Example 2 except that the weak anchoring film 34 and the strong anchoring film 36 are provided on the substrate 16 side in the cell of the liquid crystal display device 10 shown in Fig. A weak anchoring film is provided on the front side of the side.

Example 1 and Comparative Example 1, the voltage to give a threshold voltage V _th, the maximum transmittance T _max for the second respective V _max, the minimum transmittance T _O, the maximum transmittance T _max, contrast ratio CR, the response time and the voltage offset τ _off are shown in Table 1. The threshold voltage V _th is defined as a voltage V _2% which realizes a transmittance corresponding to 2% of T _max . In addition, actual measured values were used for the minimum transmittance T _o of Comparative Examples 1 and 2. Example 1 The minimum transmittance T _O is the actually measured value of the so considered to be the same value as the theoretically minimum transmittance T _O of Comparative Example 2, the minimum transmittance of Example 1 T _O is a minimum transmittance in Comparative Example 1 T _O of Used.

Table 1

As shown in Table 1, in Example 1, the maximum transmittance T _max was improved to 1.25 times that of Comparative Example 1 in which a steel anchoring film was formed on the entire surface of the substrate 16 side. Further, in Example 1, the contrast ratio CR was improved to 1.6 times that of Comparative Example 1. [ In Example 1, the response time τ _off at the time of voltage _off is reduced by 63% as compared with Comparative Example 2 in which a weak anchoring film is formed on the entire surface of the substrate 16 side.

From the above evaluation results, it can be seen that the light transmittance was improved and the response at the time of voltage off was improved in the first embodiment.

<Modified Embodiment>

The present invention is not limited to the above-described embodiment, and various modifications are possible.

For example, in the above embodiment, the case where a plurality of linear electrodes 24 are formed has been described as an example, but the present invention is not limited thereto. Instead of the plurality of linear electrodes 24, electrodes having various shapes can be formed.

In the above embodiment, the case where the orientation film made of the polyimide film is formed as the steel anchoring film 32 is described as an example, but the present invention is not limited thereto. As the steel anchoring film 32, an orientation film made of various materials can be formed.

In the above embodiment, the case where the UV anchoring monomer 362 is used as the photopolymerizable monomer and the strong anchoring film 36 is formed by the polymerization phase separation has been described as an example, but the present invention is not limited thereto. Various photopolymerizable monomers other than the UV polymerizable monomer 362 can be used and the strong anchoring film 36 can be formed by the polymerization phase separation. The material for forming the steel anchoring film 36 may be a photopolymerizable material that is polymerized by light irradiation. The photopolymerizable material may be a photopolymerizable oligomer such as a UV polymerizable oligomer in addition to a photopolymerizable monomer.

10: liquid crystal display device 12: liquid crystal panel
16: substrate 18: substrate
20: liquid crystal layer 24: linear electrode
32: steel anchoring film 34: weak anchoring film
36: steel anchoring film 38: base film

Claims (15)

A first substrate,
A second substrate facing the first substrate,
A liquid crystal layer interposed between the first substrate and the second substrate;
A plurality of electrodes formed on the surface of the first substrate facing the liquid crystal layer and configured to be able to form an electric field in a plane horizontal to the first substrate;
A first alignment layer formed directly on the plurality of electrodes,
A second alignment film formed on the first substrate between the plurality of electrodes,
And a third alignment film formed on the liquid crystal layer side of the second substrate,
Wherein the anchoring energy of the first alignment layer is smaller than the anchoring energy of the second and third alignment layers,
Wherein the second alignment layer has a higher affinity with a region on the first substrate between the plurality of electrodes than the first alignment layer,
And an IPS (In-Plane Switching) system in which display is controlled by rotating liquid crystal molecules in a plane of the liquid crystal layer by an electric field formed in a plane horizontal to the first substrate.
The method according to claim 1,
And the second alignment film comprises a polymer phase separation film selectively formed on the first substrate between the plurality of electrodes.
3. The method according to claim 1 or 2,
And a base film formed between the first substrate and the second alignment film between the plurality of electrodes,
Wherein the second alignment film has higher affinity with the base film than the first alignment film.
The method of claim 3,
Wherein the base film is a non-exposed photosensitive resin film.
5. The method of claim 4,
Wherein the first alignment film comprises the exposed photosensitive resin film.
3. The method according to claim 1 or 2,
And the second alignment film is formed directly on the first substrate between the plurality of electrodes.
3. The method according to claim 1 or 2,
Wherein the plurality of electrodes are linear electrodes, respectively, and constitute a comb electrode.
3. The method according to claim 1 or 2,
And an anchoring energy of the first alignment layer is 10 &lt; ^-6 &gt; J / m &lt; ² &gt; or less.
3. The method according to claim 1 or 2,
Wherein the anchoring energy of the second alignment layer is equal to the anchoring energy of the third alignment layer.
3. The method according to claim 1 or 2,
Wherein the main material of the plurality of electrodes is any one of ITO, IZO, AZO, GZO, and ATO.
A liquid crystal display device comprising: a first substrate; a second substrate facing the first substrate; a liquid crystal layer interposed between the first substrate and the second substrate; and a liquid crystal layer formed on the liquid crystal layer side of the first substrate, A first alignment film formed directly on the plurality of electrodes, a second alignment film formed on the first substrate between the plurality of electrodes, and a second alignment film formed on the second substrate, And a third alignment film formed on the liquid crystal layer side of the second substrate, wherein the anchoring energy of the first alignment film is smaller than the anchoring energy of the second and third alignment films, (In-Plane Switching) system for controlling display by rotating liquid crystal molecules in a plane of the liquid crystal layer by an electric field to be formed,
A step of forming the plurality of electrodes on the first substrate,
Forming a first alignment film having a lower affinity with a photopolymerizable material than a region on the first substrate between the plurality of electrodes immediately above the plurality of electrodes;
A step of interposing the liquid crystal layer in which the photopolymerizable material is mixed in a liquid crystal material between the first substrate and the second substrate on which the third alignment film is formed;
The second alignment film comprising a polymer phase separation in which the photopolymerizable material is polymerized and phase-separated by subjecting the photopolymerizable material in the liquid crystal layer to light irradiation to irradiate the first substrate between the plurality of electrodes, And a step of forming a second electrode on the second electrode.
12. The method of claim 11,
Wherein the step of forming the first alignment film comprises:
A step of forming a photosensitive resin film on the first substrate and the plurality of electrodes,
Forming a base film made of the photosensitive resin film not exposed on the first substrate between the plurality of electrodes by selectively exposing the photosensitive resin film immediately above the plurality of electrodes, And forming the first alignment film made of the photosensitive resin film having a lower affinity with the photopolymerizable material than the base film.
13. The method according to claim 11 or 12,
Wherein the photopolymerizable material is an ultraviolet polymerizable monomer. 12. The method of claim 11,
Wherein a gap between the plurality of electrodes is larger than a width of each of the electrodes.
The method according to claim 1,
Wherein a width of each of the plurality of electrodes is larger than a width of each of the electrodes.

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