KR102049742B1 - Liquid crystal display device and Method of fabricating the same - Google Patents

Abstract

An object of this invention is to provide the liquid crystal display device which can improve the responsiveness at the time of voltage OFF, improving light transmittance and contrast ratio.
A liquid crystal display device according to the present invention includes 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 surface on the liquid crystal layer side of the first substrate. A plurality of electrodes formed on the substrate and configured to form an electric field horizontal to the substrate surfaces of the first substrate and the second substrate, a first alignment film formed on a part of the plurality of electrodes, and a first substrate between the plurality of electrodes It has a 2nd alignment film formed on the remaining part of an image and several electrodes, and the 3rd alignment film formed in the liquid crystal layer side of a 2nd board | substrate, and the anchoring energy of a 1st alignment film is smaller than the anchoring energy of a 2nd and 3rd alignment film. .

Description

Liquid crystal display device and method of fabricating the same

This invention relates to a liquid crystal display device and a manufacturing method of a liquid crystal display device.

As a display method of a liquid crystal panel, an In-Plane Switching (IPS) method is known in which a display is controlled by applying a voltage to an electrode formed on a glass substrate to form an electric field horizontal to the substrate surface. In the IPS method, since the appearance length (refractive index ellipsoid) of the liquid crystal molecules becomes substantially constant regardless of the viewing angle direction of the liquid crystal panel, the viewing angle characteristic is excellent.

In the liquid crystal panel, the alignment direction of the liquid crystal molecules is regulated so that the liquid crystal molecules are aligned along a predetermined direction in the state where no electric field is applied. As a method for regulating the orientation direction of liquid crystal molecules in a liquid crystal panel of the IPS system, a rubbing method, a photoalignment 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. The photo-alignment method is to give anisotropy to the surface of an oriented film by irradiating the ultraviolet-ray which is linearly polarized light with respect to the surface of the oriented film which consists of polyimide films etc. In the liquid crystal panel of the conventional IPS system, an alignment film is formed in each of the inside of a pair of board | substrates which sandwich a liquid crystal composition (patent document 1).

However, in the liquid crystal panel of the conventional IPS system as described in Patent Literature 1, a slight deviation may occur in the alignment direction of the alignment film formed on the pair of substrates sandwiching the liquid crystal layer, respectively. The shift | offset | difference of the orientation direction of an orientation film is caused, for example by the shift | offset at the time of a rubbing process, and the shift | offset at the time of bonding of both board | substrates. If such an alignment misalignment exists, a slight twist occurs in the liquid crystal molecules of the liquid crystal layer even when the voltage is off. A slight twist of the liquid crystal molecules at the time of power supply off causes a light leakage in the black display and causes a decrease in the contrast ratio. In addition, in the conventional IPS type liquid crystal panel, a vertical electric field is formed on the comb electrode for forming a transverse electric field horizontal to the substrate surface and perpendicular to the substrate surface when voltage is turned on. Accordingly, the liquid crystal molecules are not twisted sufficiently in the lateral direction, and as a result, light transmission on the comb electrode becomes difficult, resulting in a decrease in the light transmittance of the liquid crystal panel. That is, the opening ratio of the liquid crystal panel is lowered.

Then, the patent document 2 has proposed the liquid crystal panel in which the weakly anchoring alignment film is formed in the opposing one board | substrate, and the strong anchoring alignment film was formed in the other board | substrate. In the liquid crystal panel described in Patent Literature 2, the weakly anchoring alignment film has a smaller constraint force that restricts the alignment direction of the liquid crystal molecules when an electric field is applied, than the strong anchoring alignment film. By such a structure, in the liquid crystal panel of patent document 2, the display with high light transmittance is implement | achieved.

Patent Document 1: Japanese Patent Publication No. 2940354 Patent Document 2: Japanese Patent Application Laid-Open No. 2016-170389

However, in the liquid crystal panel of patent document 2, since the anchoring energy became small in the whole area | region of the weak-anchoring alignment film formed in the opposing one board | substrate, the restoring force at the time of voltage off became weak. Therefore, the responsiveness at the time of voltage off falls, and the response time (turn off time) (tau) off at the time of voltage _off becomes long.

An object of the present invention is to provide a liquid crystal display device capable of improving the response at the time of voltage-off while improving the light transmittance and contrast ratio. Moreover, an object of this invention is to provide the manufacturing method of the liquid crystal display device which can manufacture such a liquid crystal display device easily, without accompanying process complexity.

According to one aspect of the present invention, a first substrate, a second substrate facing the first substrate, a liquid crystal layer interposed between the first substrate and the second substrate, and the liquid crystal of the first substrate A plurality of electrodes formed on the surface on the layer side and configured to form an electric field in a plane parallel to the first substrate, a first alignment film formed on a part of the plurality of electrodes, and the plurality of electrodes And a second alignment film formed on the first substrate and on the remaining portion of 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 determined by the second and A liquid crystal display device is provided which is smaller than the anchoring energy of the third alignment layer.

According to another aspect of the invention, a first substrate, a second substrate facing the first substrate, a liquid crystal layer interposed between the first substrate and the second substrate, and the liquid crystal layer of the first substrate A plurality of electrodes formed on the side surface and configured to form an electric field in a plane parallel to the first substrate, a first alignment film formed on a part of the plurality of electrodes, and the first electrode between the plurality of electrodes. The second alignment film formed on the 1st board | substrate and on the remaining part of the said some electrode, and the 3rd alignment film formed in the said liquid crystal layer side of the said 2nd board | substrate, The anchoring energy of the said 1st alignment film is the said 2nd and 3rd A method of manufacturing a liquid crystal display device smaller than the anchoring energy of an alignment layer, comprising: forming a conductive film on a surface of the first substrate on the side of the liquid crystal layer, and forming a photoresist film on the conductive film. Exposing the first pattern and the second pattern to the photoresist film using a mask having a process and a pattern having the plurality of electrodes including first and second patterns having different transmittances of mutual exposure light. And developing the photoresist film to form a first photoresist film having the first pattern and a second photoresist film having the second pattern on the conductive film, and the first photoresist film. And etching the conductive film using the second photoresist film as a mask to form the plurality of electrodes made of the conductive film, and leaving the first photoresist film and removing the second photoresist film. On the part of the electrodes of the hole for forming the first alignment film made of the first photoresist film And, a method for manufacturing a liquid crystal display device characterized by having the step of forming the second alignment layer is provided on the other of the first substrate and the plurality of electrode portions between the electrodes.

According to the present invention, in the liquid crystal display device, the response at the time of voltage-off can be improved while improving the light transmittance and contrast ratio. According to the present invention, a liquid crystal display device capable of improving the response at the time of voltage-off while improving the light transmittance and contrast ratio can be easily manufactured without the complexity of the process.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the structure of the liquid crystal display device when the liquid crystal of dielectric constant anisotropy which concerns on one Embodiment of this invention was used.
2 is a cross-sectional view (1) illustrating a method of manufacturing a liquid crystal display device in the case where a liquid crystal having a positive dielectric anisotropy according to one embodiment of the present invention is used.
3 is a cross-sectional view (2) illustrating a method of manufacturing a liquid crystal display device according to an embodiment of the present invention.
4 is a cross-sectional view 3 showing the method for manufacturing the liquid crystal display device according to the embodiment of the present invention.
5 is a cross-sectional view 4 illustrating the method of manufacturing the liquid crystal display device according to the exemplary embodiment of the present invention.
6 is a cross-sectional view showing the structure of a liquid crystal display device according to a modification of one embodiment of the present invention.
7 is a cross-sectional view showing a cell configuration of a liquid crystal display device in the case of using a liquid crystal having a positive (positive) dielectric constant anisotropy according to the Examples and Comparative Examples.
8 is a graph illustrating a result of measuring a driving voltage-light transmittance curve indicating a relationship between a driving voltage and a light transmittance of a liquid crystal panel for a liquid crystal display device according to an exemplary embodiment and a comparative example.

<One Embodiment>

EMBODIMENT OF THE INVENTION The liquid crystal display device and the manufacturing method of a liquid crystal display device which concern on one Embodiment of this invention are demonstrated with FIGS.

First, the structure of the liquid crystal display device which concerns on this embodiment is demonstrated with FIG. 1 is a cross-sectional view showing the structure of a liquid crystal display device according to the present embodiment. 1 illustrates the case where a liquid crystal layer is formed using a positive liquid crystal material.

The liquid crystal display device according to the present embodiment has a liquid crystal panel of an IPS system and controls display by forming an electric field in a horizontal direction with the substrate surface. As shown in FIG. 1, the liquid crystal display device 10 according to the present embodiment includes an IPS system liquid crystal panel 12 and a backlight unit 14. The liquid crystal panel 12 includes a display area 16 including pixels and a pad area 18.

The liquid crystal panel 12 has a pair of substrates 20 and 22 disposed to face each other. The substrates 20 and 22 are disposed to face each other in the display area 16 via the liquid crystal layer 24. The substrates 20 and 22 are bonded to each other at predetermined intervals by the sealing material 26 disposed in the peripheral portion of the display region 16. The liquid crystal which comprises the liquid crystal layer 24 between the board | substrates 20 and 22 is sealed by the sealing material 26. As shown in FIG. Although the material will not be specifically limited if the board | substrate 20 and 22 is a board | substrate which has translucentness, respectively, For example, it is a glass substrate. As the liquid crystal material constituting the liquid crystal layer 24, 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. . In addition, in FIG. 1, the liquid crystal molecule 242 of the liquid crystal layer 24 at the time of the voltage off with respect to the linear electrode 28 mentioned later is shown typically.

For example, the substrate 20 is a TFT substrate on which thin film transistors (TFTs), gate lines, source lines, etc., for switching pixels are formed. The substrate 22 is a CF substrate on which color filters (CF) are formed.

In the display area 16, a plurality of linear electrodes 28 are formed on the surface of the substrate 20, 22 on the liquid crystal layer 24 side of the substrate 20 on the backlight unit 14 side. The plurality of linear electrodes 28 are arranged in parallel with a predetermined distance from each other, and constitute a comb tooth electrode. More specifically, the plurality of linear electrodes 28 constitute a comb teeth pixel electrode and a comb teeth common electrode. 1 shows a cross section orthogonal to the longitudinal direction of the linear electrode 28. The plurality of linear electrodes 28 are configured to be able to form an electric field in the horizontal direction with the substrate surface of the substrate 20, that is, to form an electric field in the surface parallel to the substrate 20.

The linear electrode 28 is, for example, a transparent electrode made of indium tin oxide (ITO) having a high light transmittance T of 88%. In addition, the main material of the linear electrode 28 is not limited to ITO. The linear electrode 28 is preferably a transparent conductive film or a conductive film having a high light transmittance. As the main material of the linear electrode 28, for example, IZO (Indium Zinc Oxide, T = 85%) and AZO (Aluminum doped Zinc Oxide, T = 92%) can be used instead of ITO. In addition, GZO (Gallium doped Zinc Oxide, T = 92%), ATO (Antimony Tin Oxide, T = 87%) may be used.

The control unit (not shown) of the liquid crystal display device 10 applies a voltage to the linear electrode 28 of the substrate 20 to form an electric field in a horizontal direction with the substrate surface of the substrate 20, thereby forming a liquid crystal layer 24. The display of the liquid crystal panel 12 is controlled by rotating the liquid crystal molecules.

In the pad region 18, on the substrate 20, a plurality of electrode pads 30 are formed on the same layer as the plurality of linear electrodes 28. The plurality of electrode pads 30 are formed of the same material as the linear electrodes 28 in the display region 16. The plurality of electrode pads 30 are connected to a gate line, a source line, and the like, which are not illustrated in the substrate 20 in the display region 16. A driver integrated circuit (IC) (not shown) is connected to the plurality of electrode pads 30 by mounting techniques such as chip on film (COF), tape automated bonding (TAB), chip on glass (COG), and the like.

In the liquid crystal panel 12, the polarizing plates 32 and 34 are provided in each outer surface like the board | substrates 20 and 22 through. The polarization axis directions of the polarizing plates 32 and 34 are set so that the light illuminated from the backlight unit 14 passes when a voltage is applied to the linear electrode 28. For example, the polarization axis directions of the polarizing plates 32 and 34 are perpendicular to each other. In addition, the polarization axis direction of the polarizing plates 32 and 34 may be set so that the light illuminated from the backlight unit 14 may be cut off when a voltage is applied to the linear electrode 28.

On the surface of the liquid crystal layer 24 side of the substrate 22, a strong anchoring film 36 is formed as an alignment film over the entire surface of the liquid crystal layer 24. The strong anchoring film 36 is made of, for example, a polyimide film subjected to an alignment treatment by a rubbing method. The strong anchoring film 36 matches the liquid crystal molecule orientation of the liquid crystal layer 24 with respect to the linear electrode 28 at the time of voltage OFF with the board | substrate 20 side strong anchoring film 40 mentioned later. The orientation direction of the liquid crystal molecules of the liquid crystal layer 24 at the time of voltage off is a direction along the longitudinal direction of the linear electrode 28 or the direction which forms a predetermined angle with respect to the longitudinal direction of the linear electrode 28, for example. .

On the other hand, between the substrate 20 and the liquid crystal layer 24, a weak anchoring film 38 is formed on the part of the plurality of linear electrodes 28 formed on the substrate 20 as an alignment film. The weak anchoring film 38 is formed directly on a part of the plurality of linear electrodes 28. The weak anchoring film 38 is an alignment film having a smaller anchoring energy than the strong anchoring film 36 on the substrate 22 side and the strong anchoring film 40 described below. The anchoring in the strong anchoring films 36 and 40 and the weak anchoring film 38 relates to anchoring in the azimuth direction, and the magnitude of the anchoring energy is related to the anchoring energy in the azimuth direction. The weak anchoring film 38 is formed directly on the linear electrode 28 by filtering each of the plurality of linear electrodes 28 arranged in parallel with each other. The weak anchoring film 38 is made of a resin film, and more specifically, a photoresist film 52a used as a mask during etching for patterning the linear electrode 28 as described later.

Further, the weak anchoring film 38 is not formed on any of the plurality of electrode pads 30 in the pad region 18 formed on the same layer as the linear electrode 28. The surface of each of the plurality of electrode pads 30 is exposed.

On the substrate 20 between the linear electrodes 28 on which the weak anchoring film 38 is formed, a strong anchoring film 40 is formed as an alignment film. The strong anchoring film 40 is also formed on the linear electrodes 28 other than the linear electrodes 28 on which the weak anchoring film 38 is formed, that is, on the remaining portions of the plurality of linear electrodes 28. The anchoring energy of the strong anchoring film 40 is, for example, about the same as the anchoring energy of the strong anchoring film 36. The strong anchoring film 40 is, for example, a polyimide film subjected to an alignment treatment by a photoalignment method.

As described above, the strong anchoring film 36 is formed on the substrate 22 side as the alignment film. On the other hand, on the substrate 20 side, the weak anchoring film 38 is formed as an alignment film directly on a part of the plurality of linear electrodes 28. Moreover, on the board | substrate 20 side, the board | substrate 20 and the board | substrate 20 on the linear electrodes 28 other than the linear electrode 28 in which the weakly anchoring film 38 was formed directly on the remainder part of the some linear electrode 28, ie, on the above, ), An strong anchoring film 40 is formed as an alignment film.

The anchoring energy of the weak anchoring film 38 is smaller than the anchoring energy of the strong anchoring films 36 and 40, and is preferably 10 ^-6 J / m ² or less. The anchoring energy of the strong anchoring films 36 and 40 is larger than the anchoring energy of the weak anchoring film 38, and preferably 10 ⁻⁴ J / m ² or more.

A color filter 42 is provided between the substrate 22 and the strong anchoring film 36. The color filter 42 is constituted by three primary color patterns of R (red) / G (green) / B (blue), which are color resists, a black matrix, a protective film, and the like, and R / G among lights illuminated from the backlight unit 14. / B Passes light in the wavelength range of three primary colors.

The backlight unit 14 is an illuminating device that emits light for illuminating the liquid crystal panel 12. The backlight unit 14 may be an edge light method or a direct type method. In addition, 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 forms an lateral electric field in a horizontal direction with the substrate surface of the substrate 20, and rotates the liquid crystal molecules in the surface of the liquid crystal layer 24 to control the display. It is However, in the above structure, in the case where the strong anchoring film is formed on the entire surface of the substrate 20 side including immediately above the linear electrode 28 as in the conventional configuration described in Patent Document 1 described above, the linear electrode ( The liquid crystal molecules directly above 28 cannot be rotated sufficiently. This is because the component horizontal to the substrate surface of the electric field immediately above the linear electrode 28 for forming the electric field is not large enough to overcome the confinement of the strong anchoring film and rotate the liquid crystal molecules. Therefore, in this case, the light transmittance in white display falls.

On the other hand, if the weak anchoring film is formed on the entire surface of the substrate 20 side as in the conventional configuration described in Patent Document 2 described above, on the other hand, high light transmittance is realized by weakening the orientation control force on the substrate 20 side. Thus, sufficient light transmittance in white display can be ensured. However, in this case, since the restoring force of the liquid crystal molecules with respect to the linear electrode 28 at the time of voltage off falls, the response at the time of voltage off falls, and the response time (tau) _off at the time of voltage _off becomes long.

In the liquid crystal display device 10 according to the present embodiment, a weak anchoring film 38 having a relatively small anchoring energy is formed in the liquid crystal display device 10 according to the present embodiment, as compared with the above conventional configuration. On the linear electrode 28 in which the weak anchoring film 38 was formed, the orientation control force was weak compared with the area | region in which the strong anchoring film 40 was formed. Therefore, in the liquid crystal display device 10 according to the present embodiment, even when the transverse component of the electric field is small, the liquid crystal molecules directly above the linear electrode 28 on which the weak anchoring film 38 is formed rotate, so that the linear electrode Sufficient light transmittance can be ensured also directly above (28). Thereby, the liquid crystal display device 10 which concerns on this embodiment can improve light transmittance.

In addition, since the weak anchoring film 38 is formed, immediately above the linear electrode 28 on which the weak anchoring film 38 is formed, the alignment direction of the liquid crystal molecules on the substrate 20 side and the side of the substrate 22 on the substrate 22 side are formed. A slight twist of the liquid crystal molecules at the time of voltage off due to the shift in the alignment direction of the liquid crystal molecules can be suppressed. As a result, the black luminance can be reduced, and the contrast ratio can be improved while improving the light transmittance.

In addition, the weak anchoring film 38 is formed by controlling the exposure amount of the photoresist film for each region using a halftone mask in the exposure step of the photoresist film as described later. Therefore, the liquid crystal display device 10 which concerns on this embodiment can be manufactured easily, without increasing the number of processes and accompanying complexity of a process.

Furthermore, in the liquid crystal display device 10 according to the present embodiment, a linear shape in which the weak anchoring film 38 is formed on the substrate 20 and the linear anchoring film 38 directly between the linear electrodes 28 having the weak anchoring film 38 formed thereon. The strong anchoring film 40 is formed on the linear electrodes 28 other than the electrodes 28. As described above, the strong anchoring film 40 having a relatively high anchoring energy is formed in a region other than just above a part of the plurality of linear electrodes 28, thereby providing a linear electrode 28 with the voltage off. The restoring force of the liquid crystal molecules hardly decreases. Therefore, the liquid crystal display device 10 which concerns on this embodiment has the responsiveness of the liquid crystal display at the time of voltage OFF compared with the conventional structure in which the weak anchoring film was formed in the whole surface of the board | substrate 20 side as described in patent document 2 It is possible to improve the response time τ _off at the time of voltage off.

Thus, the liquid crystal display device 10 which concerns on this embodiment can improve the responsiveness at the time of voltage OFF, improving light transmittance and contrast ratio, and can achieve the brightness and responsiveness of a liquid crystal display.

Next, the manufacturing method of the liquid crystal display device which concerns on this embodiment is demonstrated with FIGS. 2-5 is sectional drawing which shows the manufacturing method of the liquid crystal display device which concerns on this embodiment.

First, an electric field (lateral electric field) is placed in a direction parallel to the substrate surface of the substrate 20 on the surface that becomes the liquid crystal layer 24 side of the substrate 20 in the display region 16 and the pad region 18. As a comb tooth electrode for formation, the transparent conductive film 50 which consists of ITO, for example is formed (FIG. 2 (a)). In the substrate 20, TFTs, gate lines, source lines and the like for switching pixels are formed.

Subsequently, a negative photoresist material is applied on the transparent conductive film 50 in the display region 16 and the pad region 18 by, for example, spin coating and pre-baked. The photoresist film 52 is formed (FIG. 2B). The photoresist film 52 is made of a material capable of functioning as the weak anchoring film 38.

Subsequently, the mask pattern of the halftone mask 54 is exposed to the photoresist film 52 using the halftone mask 54 (FIG. 3A). The halftone mask 54 has patterns 542a and 542b of the plurality of linear electrodes 28 and patterns 544 of the plurality of electrode pads 30 as mask patterns. Among the patterns 542a and 542b of the plurality of linear electrodes 28, the pattern 542a is a pattern of the linear electrodes 28 on which the weak anchoring film 38 is formed. The pattern 542b is a pattern of the linear electrodes 28 other than the linear electrodes 28 on which the weak anchoring film 38 is formed. The transmittances of the exposure light of the patterns 542a, 542b, and 544 are different from each other. That is, the transmittance of the exposure light of the pattern 542a is higher than the transmittance of the exposure light of the pattern 542b and the transmittance of the exposure light of the pattern 544. In addition, the transmittance of the exposure light of the pattern 542b may be the same as the transmittance of the exposure light of the pattern 544. As the exposure light, ultraviolet light or the like can be selected according to the type of the photoresist film 52.

In this manner, the exposure amounts of the photoresist films 52a, 52b, and 52c to which the patterns 542a, 542b, and 544 are exposed in the photoresist film 52 are different by exposure using the halftone mask 54 having different transmittances of exposure light. . That is, the exposure amount of the photoresist film 52a to which the pattern 542a is exposed is greater than the exposure amount of the photoresist film 52b to which the pattern 542b is exposed and the exposure amount of the photoresist film 52c to which the pattern 544 is exposed. Big. In this way, the degree of curing of the photoresist films 52a, 52b, 52c is adjusted by controlling the exposure amounts of the photoresist films 52a, 52b, 52c by exposure using the halftone mask 54.

Subsequently, the photoresist film 52 is developed to remove the unexposed photoresist film 52, and then post-bake. As a result, photoresist films 52a, 52b, and 52c are formed on the transparent conductive film 50 (FIG. 3B). As described above, since the exposure amount of the photoresist film 52a is higher than the exposure amounts of the photoresist films 52b and 52c, the degree of curing of the photoresist film 52a is higher than that of the photoresist films 52b and 52c. Therefore, after development, the film thickness of the photoresist film 52a is larger than the film thickness of the photoresist films 52b and 52c.

Subsequently, the transparent conductive film 50 is etched and patterned using the photoresist films 52a, 52b, and 52c as a mask, for example, by wet etching. As a result, a plurality of linear electrodes 28 made of the transparent conductive film 50 are formed in the display region 16, while a plurality of electrode pads made of the transparent conductive film 50 are formed in the pad region 18. 30) (FIG. 4 (a)).

Subsequently, for example, the photoresist film 52a on the linear electrode 28 and the photoresist on the electrode pad 30 while the photoresist film 52a remains directly on the linear electrode 28 by being immersed in a stripping solution, for example. The film 52c is removed. Since the photoresist film 52a is thicker than the photoresist films 52b and 52c, the photoresist film 52a can be selectively left on the linear electrode 28. In this way, a weak anchoring film 38 made of the photoresist film 52a is formed directly on a part of the plurality of linear electrodes 28 (Fig. 4 (b)). In addition, when the photoresist films 52b and 53c cannot be removed completely by the peeling process, plasma ashing or the like is performed.

In the etching process shown in Fig. 4A, the photoresist films 52a, 52b, and 52c are selectively removed from the photoresist films 52a, 52b, and 52c. You can set the thickness. In this case, the peeling process and the ashing process shown in FIG. 4 (b) can be omitted.

Next, the polyimide film is formed on the board | substrate 20 in the display area 16 by the printing method, for example. Here, the photoresist film 52a constituting the weak anchoring film 38 has no affinity for the polyimide film. Therefore, the polyimide film is not formed on the weak anchoring film 38 made of the photoresist film 52a, and on the substrate 20 between the linear electrodes 28, and the weak anchoring film 38 is not formed immediately above. It is formed on the linear electrode 28. Subsequently, the polyimide film is subjected to an alignment treatment by, for example, a photoalignment method. In this way, the strong anchoring film 40 which consists of a polyimide film is formed on the board | substrate 20 between the linear electrodes 28, and on the linear electrode 28 in which the weak anchoring film 38 is not formed directly above. (FIG. 5 (a)).

On the other hand, the color filter 42 is formed on the board | substrate 22 in the display area 16. FIG. Subsequently, a polyimide film is formed on the color filter 42. Subsequently, the polyimide film is subjected to an alignment treatment by, for example, a rubbing method, a photoalignment method, or the like. In this way, the strong anchoring film 36 which consists of a polyimide film is formed on the color filter 42. FIG.

Subsequently, the liquid crystal layer 24 is sealed between the substrates 20 and 22 by ODF (One Drop Fill) method. First, the sealing material 26 which consists of ultraviolet curable resin is apply | coated on one of the board | substrates 20 and 22 in the peripheral part of the display area 16. FIG. Subsequently, a liquid crystal material is dripped on one of the board | substrates 20 and 22 which apply | coated the sealing material 26. Then, one of the board | substrates 20 and 22 in which the liquid crystal material was dripped, and the other of the board | substrates 20 and 22 are bonded by the sealing material 26. Between the board | substrates 20 and 22, the liquid crystal layer 24 which consists of a liquid crystal material dripped is formed. Subsequently, the sealing material 26 is hardened by irradiating an ultraviolet light. Thus, by the ODF method, the board | substrate 20 and the board | substrate 22 are bonded together like the liquid crystal layer 24 which consists of liquid crystal materials, and the liquid crystal layer 24 is sealed between board | substrates 20 and 22 ( 5 (b)).

Thereafter, the polarizing plates 32 and 34 are bonded to the substrates 20 and 22, the driver IC is mounted, and the backlight unit 14 is disposed according to a conventional process. In this way, 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 photoresist films 52a and 52b used as masks when etching the transparent conductive film 50 constituting the linear electrode 28 by exposure using the halftone mask 54 as a mask. , The exposure amount of 52c) is controlled. Thereby, the weak anchoring film 38 made of the photoresist film 52a is formed directly on a part of the plurality of linear electrodes 28. Therefore, in this embodiment, in order to form the weak anchoring film 38, an additional process, such as a process of patterning a separate photoresist film, is not required, and the number of processes does not increase. Therefore, according to this embodiment, the liquid crystal display device 10 shown in FIG. 1 can be manufactured easily, without accompanying process complexity.

Thus, according to this embodiment, in the liquid crystal display device 10, the response at the time of voltage off can be improved, improving the light transmittance and contrast ratio. In addition, according to the present embodiment, the liquid crystal display device 10 capable of improving the response at the time of voltage-off while improving the light transmittance and contrast ratio can be easily manufactured without the complexity of the process.

<Variation example>

Next, the liquid crystal display device which concerns on the modification of this embodiment is demonstrated with FIG. 6 is a cross-sectional view showing the structure of a liquid crystal display device according to a modification of the present embodiment.

In the liquid crystal display device 10 shown in FIG. 1, the weak anchoring film 38 is formed directly on the linear electrode 28 by filtering every one of the plurality of linear electrodes 28 arranged in parallel with each other. It was, but it is not limited to this. The weak anchoring film 38 may be formed directly on the linear electrode 28 at a plurality of intervals among the plurality of linear electrodes 28 arranged in parallel with each other.

For example, the weak anchoring film 38 can be formed directly on the linear electrode 28 at two intervals from among the plurality of linear electrodes 28. In the liquid crystal display device 100 according to the modification shown in FIG. 6, the weak anchoring film 38 is formed of the linear electrodes 28 at two intervals from among the plurality of linear electrodes 28 arranged in parallel with each other. It is formed just above it.

In this way, the ratio of the linear electrode 28 in which the weak-anchoring film 38 is formed directly in the some linear electrode 28 can be changed. Thereby, the brightness and responsiveness of the liquid crystal display can be adjusted.

In addition, in the above description, by controlling the exposure amounts of the photoresist films 52a, 52b, and 52c by exposure using the halftone mask 54, the weakly anchoring film 38 is placed directly above a part of the plurality of linear electrodes 28. FIG. Although selectively formed, it is not limited to this. For example, the weak anchoring film 38 may be selectively formed directly on a part of the plurality of linear electrodes 28 by coating the material of the weak anchoring film 38 separately by a printing method such as an inkjet method.

<Evaluation result>

Next, the evaluation result of the liquid crystal display device which concerns on this embodiment is demonstrated.

First, for each of the liquid crystal display devices according to Examples 1 and 2 and Comparative Examples 1, 2 and 3, the response time tau _off at the time of voltage _off was measured and the response speed was evaluated. The cell structure of the liquid crystal display device which concerns on each Example and the comparative example is as follows. 7A is a cross-sectional view showing the cell configuration of the first embodiment. 7B is a cross-sectional view showing the cell configuration of Comparative Example 1. FIG.

The cell configuration of Example 1 is as follows. Glass substrates were used as the substrates 20 and 22, respectively. ITO was used as a material of the linear electrode 28 which comprises a comb electrode. Furthermore, the strong anchoring film 40 was formed on the board | substrate 20 in which the linear electrode 28 was formed. As a material of the strong anchoring film 40, the polyimide was used and the orientation process by the rubbing method was performed. On the strong anchoring film 40, the weak anchoring film 38 was formed by the inkjet method. The weak anchoring film 38 was formed directly on the linear electrode 28 at one interval from among the plurality of linear electrodes 28. The gap between the substrates 20 and 22, that is, the thickness of the liquid crystal layer 24 was set to 3.0 μm. As the material of the strong anchoring film 36 on the substrate 22 side, polyimide was used in the same manner as the strong anchoring film 40, and alignment treatment was performed by a rubbing method. An ITO film 60 was formed on the outer surface of the substrate 20.

The cell structure of the second embodiment is the cell of the first embodiment except that the weak anchoring film 38 is formed directly on the linear electrode 28 at two intervals among the plurality of linear electrodes 28. Same as the configuration.

The cell configuration of Comparative Example 1 is the same as that of the first embodiment except that the weak anchoring film 38 is formed on the entire surface without forming the strong anchoring film 40.

The cell configuration of Comparative Example 2 is the same as that of the first embodiment except that the weak anchoring film 38 is formed directly on each of the plurality of linear electrodes 28.

The cell structure of the comparative example 3 is the same as the cell structure of Example 1 except not having formed the weak anchoring film 38, ie, the strong anchoring film 40 formed in the whole surface.

Table 1 shows the results of measuring the response time tau _off at the time of voltage-off for the cell configurations of the above-described Examples 1 and 2 and Comparative Examples 1, 2 and 3, respectively.

TABLE 1

Compared with Comparative Example 1 in which the weak anchoring film 38 was formed on the entire surface as shown in Table 1, in Examples 1 and 2, the response time τ _off at the voltage _off was shortened, and the response at the voltage _off was reduced. It can be seen that the improvement.

Moreover, about each liquid crystal display device which concerns on Example 1, 2 and Comparative Examples 1, 2, 3, the drive voltage-light transmittance curve (V-T curve) which shows the relationship of the drive voltage and the light transmittance of a liquid crystal panel was measured. 8 is a graph showing the results of measuring the V-T curve.

As is apparent from FIG. 8, Examples 1 and 2 have a higher light transmittance than Comparative Example 3 in which the strong anchoring film 40 is formed on the entire surface, and is the same as Comparative Example 1 in which the weak anchoring film 38 is formed on the entire surface. A degree of light transmittance is obtained.

From the above evaluation results, it can be seen that in Examples 1 and 2, the light transmittance was improved while the response at the time of voltage off was improved.

Modified Embodiment

This invention is not limited to the said embodiment, A various deformation | transformation is possible.

For example, in the said embodiment, although the case where the some linear electrode 28 was formed was demonstrated to the example, it is not limited to this. Instead of the plurality of linear electrodes 28, electrodes having various shapes may be formed.

Moreover, in the said embodiment, although the case where the orientation film which consists of a polyimide film is formed as the strong anchoring films 36 and 40 was demonstrated to the example, it is not limited to this. As the strong anchoring films 36 and 40, an alignment film made of various materials can be formed.

10: liquid crystal display device 12: liquid crystal panel
16: display area 18: pad area
20: substrate 22: substrate
24: liquid crystal layer 28: linear electrode
30: electrode pad 36: strong anchoring film
38: weak anchoring film 40: strong anchoring film

Claims (18)

A first substrate,
A second substrate opposed to the first substrate,
A liquid crystal layer interposed between the first substrate and the second substrate;
A plurality of electrodes formed on a surface of the first substrate on the liquid crystal layer side and configured to form an electric field in a surface parallel to the first substrate,
A first alignment layer formed on a part of the plurality of electrodes,
A second alignment layer formed on the first substrate between the plurality of electrodes and on the remaining portion of the plurality of electrodes,
It has a 3rd alignment film formed in the said liquid crystal layer side of a said 2nd board | substrate,
The anchoring energy of the first alignment layer is smaller than the anchoring energy of the second and third alignment layers,
A gate line and a source line formed on a surface of the liquid crystal layer side of the first substrate and crossing each other to define a pixel region;
The plurality of electrodes is located in the pixel area.
A first substrate,
A second substrate opposed to the first substrate,
A liquid crystal layer interposed between the first substrate and the second substrate;
A plurality of electrodes formed on a surface of the first substrate on the liquid crystal layer side and configured to form an electric field in a surface parallel to the first substrate,
A first alignment layer formed on a part of the plurality of electrodes,
A second alignment layer formed on the first substrate between the plurality of electrodes and on the remaining portion of the plurality of electrodes,
It has a 3rd alignment film formed in the said liquid crystal layer side of a said 2nd board | substrate,
The anchoring energy of the first alignment layer is smaller than the anchoring energy of the second and third alignment layers,
The plurality of electrodes are each a linear electrode, and constitute a comb tooth electrode.
The method of claim 2,
And the first alignment layer is formed directly on the linear electrode at one or a plurality of intervals.
The method according to any one of claims 1 to 3,
Having an electrode pad formed on the first substrate,
The liquid crystal display device wherein the first alignment layer is not formed on the electrode pad.
The method of claim 4, wherein
The liquid crystal display device in which the said electrode pad is formed in the same layer as the said some electrode.
The method of claim 4, wherein
The liquid crystal display device in which the said electrode pad is formed from the same material as the said some electrode.
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 liquid crystal layer side of the first substrate and configured to form an electric field in a surface parallel to the first substrate;
A first alignment layer formed on a part of the plurality of electrodes,
A second alignment layer formed on the first substrate between the plurality of electrodes and on the remaining portion of the plurality of electrodes;
It has a 3rd alignment film formed in the said liquid crystal layer side of a said 2nd board | substrate,
The anchoring energy of the first alignment layer is smaller than the anchoring energy of the second and third alignment layers,
A liquid crystal display device wherein the first alignment layer is a photoresist film. The method according to any one of claims 1 to 3,
The anchoring energy of the first alignment layer is 10 ⁻⁶ J / m ² or less.
The method according to any one of claims 1 to 3,
A liquid crystal display device wherein the anchoring energy of the second alignment layer is equal to the anchoring energy of the third alignment layer.
The method according to any one of claims 1 to 3,
The main material of the plurality of electrodes is any one of ITO, IZO, AZO, GZO and ATO.
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 surface on the side of the liquid crystal layer of the first substrate, A plurality of electrodes configured to form an electric field in a plane parallel to the first substrate, a first alignment layer formed on a part of the plurality of electrodes, and a plurality of electrodes on the first substrate between the plurality of electrodes A liquid crystal display having a second alignment film formed on the remaining portion of the second portion and a third alignment film formed on the side of the liquid crystal layer 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. As a manufacturing method of the device,
Forming a conductive film on a surface of the first substrate on the side of the liquid crystal layer;
Forming a photoresist film on the conductive film;
Exposing the first pattern and the second pattern to the photoresist film using a mask having a pattern of the plurality of electrodes including a first pattern and a second pattern having different transmittances of exposure light;
Developing the photoresist film to form a first photoresist film having the first pattern and a second photoresist film having the second pattern on the conductive film;
Forming the plurality of electrodes made of the conductive film by etching the conductive film using the first photoresist film and the second photoresist film as a mask;
Forming the first alignment film made of the first photoresist film on a part of the plurality of electrodes by remaining the first photoresist film and removing the second photoresist film;
And forming the second alignment film on the first substrate between the plurality of electrodes and on the remaining portion of the plurality of electrodes.
The method of claim 11,
In the step of exposing the photoresist film, the third pattern is further exposed using the mask further having a third pattern having a transmittance of the exposure light different from the first pattern,
In the step of developing the photoresist film, a third photoresist film having the third pattern is further formed on the conductive film,
In the step of forming the plurality of electrodes, an electrode pad made of the conductive film is further formed by etching the conductive film using the third photoresist film as a mask,
The manufacturing method of the liquid crystal display device which removes the said 3rd photoresist film further at the process of forming a said 1st orientation film.
The method according to claim 11 or 12,
The manufacturing method of the liquid crystal display device which removes the said 2nd photoresist film by ashing at the process of forming a said 1st orientation film.
The method of claim 11,
In the step of forming the second alignment film, a polyimide film is formed on the first substrate between the plurality of electrodes and on the remaining portion of the plurality of electrodes, and the alignment treatment is performed by a photoalignment method with respect to the polyimide film. The manufacturing method of the liquid crystal display device which forms the 2nd aligning film which consists of said polyimide film | membrane. delete The method according to claim 1 or 7,
The plurality of electrodes are each a linear electrode, and constitute a comb tooth electrode.
The method of claim 16,
And the first alignment layer is formed directly on the linear electrode at one or a plurality of intervals.
The method of claim 1,
A liquid crystal display device wherein the first alignment layer is a photoresist film.

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