CN119717337A - Method for manufacturing liquid crystal display device, and exposure device - Google Patents

Abstract

A method for manufacturing a liquid crystal display device, and an exposure device, wherein display unevenness caused by repeated exposure can be suppressed by a relatively simple method. The method for manufacturing the liquid crystal display device comprises an exposure step of exposing the organic film through a photomask, wherein a part of the organic film is exposed once, and at least a part of the rest is repeatedly exposed. A photomask (40) has a slit (61 a) and a light shielding portion (62 a) in a non-repeating region (45) corresponding to one exposure, and a slit (61 b) and a light shielding portion (62 b) in a repeating region (46) corresponding to the repeated exposure. At least a part of the slits (61 b) has an opening area smaller than the opening area of the slits (61 a). The slit (61 b) is a first slit having an opening area of 75% to 100% or more, or a second slit having an opening area of more than 0% to 25% or less.

Description

Method for manufacturing liquid crystal display device, and exposure device

Technical Field

The invention relates to a method for manufacturing a liquid crystal display device, a liquid crystal display device and an exposure device.

Background

In a liquid crystal display, particularly a liquid crystal display panel for a large-sized television, an angle of view, transmittance, response time, and the like are important performance indexes. As a liquid crystal display mode for making the values of these performance indexes good, various modes such as a four-Domain reverse twisted nematic (4 Domain-REVERSE TWISTED NEMATIC, 4D-RTN) mode, a four-Domain electrically controlled birefringence (4 Domain-ELECTRICALLY CONTROLLED BIREFRINGENCE, 4D-ECB) mode, a polymer stable alignment (Polymer Sustained Alignment, PSA) mode, a coplanar switching (IN PLANE SWITCHING, IPS) mode, and a fringe field switching (FRINGE FIELD SWITCHING, FFS) mode have been developed. In addition, large-sized televisions using these liquid crystal display mode techniques are currently being mass-produced.

A liquid crystal display device is provided with a liquid crystal alignment film for controlling alignment of liquid crystal molecules in a liquid crystal cell. As a method for obtaining a liquid crystal alignment film, a method of rubbing an organic film, a method of vapor deposition of silicon oxide in an oblique direction, a method of forming a monomolecular film having a long chain alkyl group, a method of irradiating a photosensitive organic film with light (photo-alignment method), and the like are known. Among these, the photo-alignment method can provide a uniform liquid crystal alignment capability to a photosensitive organic film while suppressing the generation of static electricity or dust, and can also realize precise control of the alignment direction of liquid crystal molecules, and various researches are being advanced. When a liquid crystal aligning ability is imparted to a photosensitive organic film by a photo-alignment method, the organic film is generally irradiated with light through a photomask.

In a manufacturing process of a liquid crystal display device, a plurality of substrates having a size corresponding to one liquid crystal display device are taken out of one mother substrate, thereby improving productivity. However, in the case of manufacturing a large-sized (for example, 60-type or 70-type) liquid crystal display device by the photo-alignment method, it is not realistic to irradiate light at one time by one exposure for a large-sized substrate that can take a plurality of substrates corresponding to a large screen size. In addition, the size of the photomask increases to increase the manufacturing cost. Further, in the case of manufacturing a relatively small-sized (for example, 20-type or 30-type) liquid crystal display device, there is also a need to increase the size of the exposure device in order to reduce the manufacturing cost.

Therefore, in the case of manufacturing a liquid crystal display device by a photo-alignment method, there is an ongoing study of dividing an exposure region on a substrate into a plurality of portions, and arranging a plurality of photomasks having a size corresponding to each exposure region for exposure. However, when the exposure area is divided into a plurality of areas to be exposed, a seam between the exposure areas may appear on the screen as a display unevenness.

In order to solve the above-described problem of uneven display, it has been proposed that a seam between exposure regions is not easily visually recognized on a display screen by improving a photomask pattern (for example, see patent document 1). Patent document 1 discloses dividing a substrate surface into two or more exposure regions, exposing each exposure region to light through a photomask so that a part of the adjacent exposure regions overlap, and using a photomask having a halftone portion in a region corresponding to the overlapping exposure region. The photomask of patent document 1 has a plurality of slits in a halftone portion, and the aperture ratio of the plurality of slits continuously decreases in a direction toward an end of the mask. Patent document 1 discloses that the joint between the exposed areas is not easily visually recognized by controlling the total irradiation amount of the areas repeatedly exposed.

[ Prior Art literature ]

[ Patent literature ]

[ Patent document 1] International publication No. 2007/086474

Disclosure of Invention

[ Problem to be solved by the invention ]

The inventors of the present invention have studied and as a result, have found that according to the method described in patent document 1, the brightness of the joint between the exposed regions can be suppressed from being raised, but the joint may be locally brightened. In addition, in the method of controlling the total irradiation amount of the repeatedly exposed regions so that the joint between the exposed regions is not easily visually recognized, it is necessary to optimize the photomask pattern according to the total irradiation amount of the repeatedly exposed regions every time various conditions such as the material of the liquid crystal alignment film and the illuminance of the light source are changed, and there is a concern that the method of suppressing the display unevenness becomes complicated.

The present invention has been made in view of the above-described problems, and a main object of the present invention is to provide a method for manufacturing a liquid crystal display device, which can suppress occurrence of display unevenness due to repeated exposure by a relatively simple method.

[ Means of solving the problems ]

In order to solve the above problems, the present invention adopts the following means.

[1] A method of manufacturing a liquid crystal display device, wherein the liquid crystal display device comprises: the method for manufacturing a liquid crystal display device includes an exposure step of exposing a photosensitive organic film to light through a photomask while relatively moving the substrate on which the organic film is formed in a predetermined moving direction with respect to a light source, the exposure step exposing a part of the organic film to light through a photomask, repeatedly exposing at least a part of the remaining region, the photomask having a plurality of light transmitting portions having the same opening area in non-repeated regions corresponding to the portions of the organic film on which the first exposure is performed, and light shielding portions provided between the light transmitting portions, the organic film is provided with a plurality of light-transmitting parts having different opening areas in a repeating region corresponding to a part of the organic film where repeated exposure is performed, and light-shielding parts provided between the light-transmitting parts, wherein at least a part of the plurality of light-transmitting parts arranged in the repeating region has a smaller opening area than that of the light-transmitting parts arranged in the non-repeating region, and each light-transmitting part arranged in the repeating region is a first light-transmitting part having an opening area of 75% to 100% with respect to that of each light-transmitting part arranged in the non-repeating region, or a second light-transmitting part having an opening area of more than 0% and 25% or less.

[2] The method for manufacturing a liquid crystal display device according to item [1], wherein the photomask includes a first photomask and a second photomask that are arranged adjacent to each other along a direction intersecting the moving direction and along a substrate surface, that is, a intersecting direction, and the first photomask and the second photomask are arranged so that a part of each other overlaps when viewed in the moving direction, and the non-overlapping region is a region where the first photomask and the second photomask do not overlap when viewed in the moving direction, and the overlapping region is a region where the first photomask and the second photomask overlap when viewed in the moving direction.

[3] The method of manufacturing a liquid crystal display device according to [2], wherein the first light-transmitting portion arranged in the repetition region of one of the first photomask and the second light-transmitting portion or the light-shielding portion arranged in the repetition region of the other photomask are arranged on the same line extending in the moving direction.

[4] The method for manufacturing a liquid crystal display device according to [2] or [3], wherein the light transmitting portions are arranged in the repeated regions such that a sum of opening areas of the light transmitting portions included in a region of a predetermined length along the intersecting direction shows an increasing tendency from a photomask end portion toward the non-repeated region.

[5] The method for manufacturing a liquid crystal display device according to any one of [1] to [4], wherein in the repeated region, the first light-transmitting portion is closely arranged from a photomask end toward the non-repeated region.

[6] The method for manufacturing a liquid crystal display device according to any one of [1] to [5], wherein the repeated region has a first region adjacent to the non-repeated region, in which the first light-transmitting portion is arranged, the second light-transmitting portion is not arranged, and a second region including a photomask end, in which the second light-transmitting portion is arranged, and the first light-transmitting portion is not arranged.

[7] The method of manufacturing a liquid crystal display device according to [6], wherein a plurality of the first light-transmitting portions are arranged in the first section, and an opening area of each of the first light-transmitting portions arranged in the first section becomes smaller in a direction away from the non-overlapping region.

[8] The method for manufacturing a liquid crystal display device according to [6] or [7], wherein a plurality of the second light-transmitting portions are arranged in the second section, and an opening area of each of the second light-transmitting portions arranged in the second section becomes smaller in a direction toward an end of the photomask.

[9] The method for manufacturing a liquid crystal display device according to any one of [6] to [8], wherein the repeated region further has a third section provided between the first section and the second section, and the first light transmitting portion is disposed in the third section so as to be close to the first section from the second section.

[10] The method of manufacturing a liquid crystal display device according to [9], wherein an opening area of each first light-transmitting portion arranged in the first section becomes smaller in a direction away from the non-repeating region, and an opening area of each second light-transmitting portion arranged in the second section becomes smaller in a direction toward an end of the photomask.

[11] The method for manufacturing a liquid crystal display device according to any one of [1] to [10], wherein in the repeating region, the second light transmitting portion or the light shielding portion is arranged at a position symmetrical to the first light transmitting portion, and the first light transmitting portion is arranged at a position symmetrical to the second light transmitting portion with respect to a center line of the repeating region extending in the moving direction as an axis.

[12] The method for manufacturing a liquid crystal display device according to any one of [1] to [11], wherein the liquid crystal display device has two or more regions having different alignment orientations of liquid crystal molecules in the liquid crystal layer within one pixel.

[13] The method for manufacturing a liquid crystal display device according to any one of [1] to [12], wherein polarized ultraviolet rays are irradiated from a direction inclined with respect to a substrate surface in the exposure step.

[14] The method for manufacturing a liquid crystal display device according to any one of [1] to [13], wherein liquid crystal molecules having negative dielectric constant anisotropy are contained in the liquid crystal layer.

[15] A liquid crystal display device manufactured by the manufacturing method according to any one of [1] to [14 ].

[16] An exposure apparatus for manufacturing a photo-alignment film includes a light source; a plurality of photomasks; and a scanning unit for exposing the organic film through the plurality of photomasks while relatively moving the substrate having the photosensitive organic film with respect to the light source in a predetermined moving direction, wherein the plurality of photomasks are arranged in a direction intersecting the moving direction and along a substrate surface, that is, in the intersecting direction, and the scanning unit includes a first photomask and a second photomask adjacent to the first photomask, wherein the first photomask and the second photomask are arranged so that a part of the first photomask and the second photomask overlap each other when viewed in the moving direction, wherein the first photomask and the second photomask have a plurality of light transmitting portions having the same opening area in non-overlapping regions where the first photomask and the second photomask do not overlap when viewed in the moving direction, and a light shielding portion provided between the light transmitting portions, the first photomask and the second photomask have a plurality of light transmitting portions having different opening areas in a repetition region where the first photomask and the second photomask overlap when viewed in the moving direction, and a light shielding portion provided between the light transmitting portions, at least a part of the plurality of light transmitting portions arranged in the repetition region has a smaller opening area than the light transmitting portions arranged in the non-repetition region, and each light transmitting portion arranged in the repetition region is a first light transmitting portion having an opening area of 75% to 100% with respect to the opening area of each light transmitting portion arranged in the non-repetition region, or a second light transmitting portion having an opening area of more than 0% and 25% or less.

[ Effect of the invention ]

According to the present invention, by a relatively simple method of designing a photomask pattern by combining and disposing the first light transmitting portion and the second light transmitting portion having the opening areas in the predetermined ranges in the repetition region corresponding to the portion where the repeated exposure is performed, it is possible to suppress display unevenness occurring in the liquid crystal display device due to the repeated exposure.

Drawings

Fig. 1 is a schematic cross-sectional view showing a schematic structure of a liquid crystal display device.

Fig. 2 is a schematic plan view of the first substrate.

Fig. 3 is a view showing the irradiation direction of light to the organic film on the first substrate.

Fig. 4 is a view showing the irradiation direction of light to the organic film on the second substrate.

Fig. 5 is a view showing the direction of irradiation of light to the organic film on the first substrate and the organic film on the second substrate, and the orientation of the liquid crystal molecules in the liquid crystal layer.

Fig. 6 is a schematic diagram of an exposure apparatus and scanning exposure.

Fig. 7 is a diagram showing the arrangement of the photomask.

Fig. 8 is an enlarged view showing a schematic structure of a repetitive region of a photomask according to the first embodiment.

Fig. 9 is a graph showing the results of evaluation of the brightness of the liquid crystal cell based on repeated exposure.

Fig. 10 is an enlarged view showing a schematic configuration of a repetitive region in another example of the first embodiment.

Fig. 11 is an enlarged view showing a schematic structure of a repeated region of a photomask according to the second embodiment.

Fig. 12 is an enlarged view showing a schematic configuration of a repetitive region in another example of the second embodiment.

Fig. 13 is an enlarged view showing a schematic structure of a repetitive region of a photomask according to the third embodiment.

Fig. 14 is an enlarged view showing a schematic configuration of a repetitive region in another example of the third embodiment.

Fig. 15 is an enlarged view showing a schematic structure of a repetitive region of a photomask according to the fourth embodiment.

Fig. 16 is an enlarged view showing a schematic structure of a repetitive region of a conventional photomask.

Fig. 17 is an enlarged view showing a schematic structure of a repetitive region of a conventional photomask.

[ Description of symbols ]

10 Liquid crystal display device

29 Organic film

29A non-overlapping region

29B overlap region

30 Pixels

36 Light source

38 Substrate(s)

40 Photomask

41 First photomask

42 Second photomask

43 Joint portion

44 Mask end

45 Non-repeating region

46 Repeat region

50 Exposure apparatus

61. 61A, 61b slit (light-transmitting portion)

62. 62A, 62b light shielding portions

63 First slit (first light-transmitting portion)

64 Second slit (second light-transmitting portion)

F1 first interval

F2, second interval

F3 third interval

V cross direction

W is the scanning direction

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, the same or equivalent portions are denoted by the same reference numerals in the figures, and the description thereof is referred to with respect to the portions having the same reference numerals. In the following description, for convenience, the up-down and left-right are shown with reference to the direction when the display area of the liquid crystal display device is viewed from the front.

In the present specification, the term "pixel" refers to a minimum unit for expressing the shade (gray level) of each color in display, and for example, in a color filter type display element, the unit corresponds to a unit for expressing each gray level such as red (R), green (G), and blue (B). Accordingly, when expressed as "pixel", it refers to each pixel (sub-pixel) of R pixel, G pixel, and B pixel, rather than a color display pixel (image point) that combines R pixel, G pixel, and B pixel. That is, in the case of a color liquid crystal display element, one pixel corresponds to any one color of a color filter. The term "pretilt angle" refers to an angle between the surface of the alignment film and the long axis direction of the liquid crystal molecules in the vicinity of the alignment film in a state where no voltage is applied to the liquid crystal layer.

The term "azimuth" refers to an orientation on the substrate surface or a plane parallel to the substrate surface. The azimuth does not take into account the inclination angle of the substrate surface with respect to the normal direction. Unless otherwise specified, the azimuth indicated by 0 to 360 degrees is the azimuth (0 degree) of the reference azimuth in the right direction of the horizontal direction of the display surface (i.e., the left-right direction of the display surface, also referred to as the "pixel horizontal direction"), and the counterclockwise direction is the positive angle.

The term "alignment direction of liquid crystal molecules in the liquid crystal layer" refers to a direction in which liquid crystal molecules (more specifically, liquid crystal molecules present near the center in the layer plane of the liquid crystal layer of each pixel) present near the center in the thickness direction of the liquid crystal layer start from the long axis end on the side of the substrate (first substrate) on which the pixel electrode is disposed and end from the long axis end on the side of the other substrate (second substrate) are present near the center in the thickness direction of the liquid crystal layer. Accordingly, the term "azimuth obtained by projecting the long axis direction of the liquid crystal molecules present near the center in the thickness direction of the liquid crystal layer onto the first substrate" refers to an orientation obtained by projecting the direction of the liquid crystal molecules present near the center in the thickness direction of the liquid crystal layer onto the first substrate with the long axis end on the first substrate side as a starting point and the long axis end on the second substrate side as an ending point.

The term "tilt orientation of liquid crystal molecules" refers to an orientation of liquid crystal molecules existing in the vicinity of an alignment film, which is controlled by the liquid crystal alignment film in a state where no voltage is applied. In the present specification, the tilt orientation of the liquid crystal molecules is expressed by an orientation starting from the end of the long axis on the first substrate side and ending at the end of the long axis on the second substrate side. In the present specification, unless the visual direction is particularly shown, the orientation when the first substrate side is viewed from the front of the second substrate side is indicated.

First embodiment

Hereinafter, the structure of the liquid crystal display device 10 manufactured by the manufacturing method of the present disclosure will be described first with reference to the drawings.

< Liquid Crystal display device >

The liquid crystal display device 10 is a thin film transistor (TFT: thin Film Transistor) type liquid crystal display device, and a plurality of pixels are arranged in a matrix in a display region. As shown in fig. 1, the liquid crystal display device 10 includes a pair of substrates including a first substrate 11 and a second substrate 12, and a liquid crystal layer 13 disposed between the first substrate 11 and the second substrate 12. In the present embodiment, the case of applying to a TFT-type liquid crystal display device is described, but the present disclosure may be applied to other driving methods (for example, a passive matrix method, a plasma address (PLASMA ADDRESS) method, and the like).

The first substrate 11 is a TFT substrate (see fig. 2) in which a pixel electrode 15 including a transparent conductor such as Indium Tin Oxide (ITO), a TFT 26 as a switching element, various wirings such as a scanning signal line 17 and a data signal line 18 are arranged on a transparent substrate 14 including glass, resin, or the like. The second substrate 12 is a counter substrate in which a counter electrode 19 including a transparent conductor is provided on a transparent substrate 16 including glass, resin, or the like. The counter electrode 19 is a common electrode common to all the pixel electrodes 15. The second substrate 12 is a Color Filter (CF) substrate including a black matrix and a Color Filter. The color filter has coloring layers of three colors, for example, red (R), green (G), and blue (B). Instead of providing color filters on the opposing substrate, color filters (Color filter on array, COA) on the array provided on the pixel substrate may be used.

A liquid crystal alignment film for aligning liquid crystal molecules in the vicinity of the substrate surface in a predetermined direction with respect to the substrate surface (i.e., electrode arrangement surface) is formed on each of the first substrate 11 and the second substrate 12. The liquid crystal alignment film is a vertical alignment film that aligns liquid crystal molecules substantially vertically when no voltage is applied, and an angle (pretilt angle) between the surface of the alignment film and the long axis direction of the liquid crystal molecules in the vicinity of the alignment film is, for example, 85 ° to 89.9 °. The liquid crystal display device 10 includes, as liquid crystal alignment films, a first alignment film 22 formed on an electrode arrangement surface of the first substrate 11, and a second alignment film 23 formed on an electrode arrangement surface of the second substrate 12.

At least one of the first alignment film 22 and the second alignment film 23 is a photo-alignment film, and in this embodiment, both the first alignment film 22 and the second alignment film 23 are photo-alignment films. The photo-alignment film is formed by photo-aligning a photosensitive organic film formed on a substrate with a liquid crystal alignment agent. The liquid crystal display device 10 of the present embodiment is divided into two or more regions having different alignment directions in the pixel 30. Thereby, the viewing angle characteristic of the liquid crystal display device 10 is compensated.

As the liquid crystal aligning agent for forming the photo-alignment film, a polymer composition containing a polymer having a photo-alignment structure may be preferably used. The polymer having a photo-alignment structure is not particularly limited, and a known component can be suitably used as the polymer component of the photo-alignment film. Specific examples of the photo-alignment structure include a cinnamic acid structure, an azobenzene structure, a coumarin structure, a chalcone structure, and a cyclobutane structure. Examples of the main chain of the polymer having a photo-alignment structure include polyamic acid, polyimide, polyorganosiloxane, polyamic acid ester, polyamide, polyalkenylamine, (meth) acrylic polymer, styrene polymer, maleimide polymer, and styrene-maleimide polymer. The term "(meth) acrylic acid" includes "acrylic acid" and "methacrylic acid".

The liquid crystal aligning agent used for forming the first alignment film 22 and the second alignment film 23 may contain only one polymer as a polymer component, or may contain two or more polymers as polymer components. The liquid crystal aligning agent is generally a liquid composition in which a polymer component is dissolved or dispersed in one or two or more solvents. The liquid crystal aligning agent may contain one or more additives selected from the group consisting of a crosslinking agent, a bonding aid, an ultraviolet absorber, and a photosensitizer, in addition to the polymer component.

The first substrate 11 and the second substrate 12 are arranged with a predetermined gap (cell gap) interposed therebetween by the spacer 24 so that the electrode arrangement surface of the first substrate 11 faces the electrode arrangement surface of the second substrate 12. In fig. 1, the spacers 24 are columnar spacers, and may be other spacers for a liquid crystal display device such as bead spacers. The first substrate 11 and the second substrate 12 disposed opposite to each other are bonded to each other with a sealing member 25 interposed therebetween in the peripheral portion. The liquid crystal composition is filled in a space surrounded by the first substrate 11, the second substrate 12, and the sealing member 25, thereby forming the liquid crystal layer 13 between the first substrate 11 and the second substrate 12. The liquid crystal layer 13 contains liquid crystal having negative dielectric constant anisotropy.

As the liquid crystal, a known liquid crystal material having negative dielectric anisotropy can be used. The refractive index anisotropy Δn of the liquid crystal can be appropriately set so that the retardation (d·Δn) represented by the product of the refractive index anisotropy Δn of the liquid crystal and the thickness d of the liquid crystal layer 13 becomes a desired value. The refractive index anisotropy delta n of the liquid crystal is, for example, 0.06 to 0.14. The thickness d of the liquid crystal layer 13 is, for example, 2 μm to 5 μm.

A pair of polarizing plates are disposed outside the first substrate 11 and the second substrate 12. The pair of polarizing plates includes a first polarizing plate 27 provided on the outer surface of the first substrate 11, and a second polarizing plate 28 provided on the outer surface of the second substrate 12. In the liquid crystal display device 10, the first polarizing plate 27 and the second polarizing plate 28 are disposed so that polarizing axes thereof intersect (more specifically, are orthogonal to) each other. A terminal region (not shown) is provided at an outer edge portion of the first substrate 11, and a driver integrated circuit (INTEGRATED CIRCUITS, IC) for driving liquid crystal or the like is connected to the terminal region to drive the liquid crystal display device 10.

In addition, in the present embodiment, a vertical alignment type liquid crystal display device is described, but the present disclosure may also be applied to a horizontal alignment type liquid crystal display device. In the case of being applied to a liquid crystal display device of a horizontal alignment type, liquid crystal molecules having positive dielectric anisotropy may be used as the liquid crystal molecules of the liquid crystal layer 13, and a liquid crystal alignment film of a horizontal alignment type may be used instead of a vertical alignment film as the liquid crystal alignment film.

(Pixel Structure)

Next, the pixel structure and the alignment division of the liquid crystal display device 10 will be described with reference to fig. 3 to 5. Arrows P1 to P4 in fig. 3 to 5 indicate the irradiation direction of light to the photosensitive organic film 29 formed of the liquid crystal aligning agent. In fig. 5, the cone of symbol 35 represents liquid crystal molecules. In fig. 5, the orientation of the liquid crystal molecules in the liquid crystal layer 13 is indicated by the orientation of the cone 35. Here, a direction from the bottom surface of the cone 35 toward the apex is defined as a direction toward the first substrate 11. In the following description, the first substrate 11 is viewed from above, and the direction along the short side direction of the pixel 30 is referred to as the X-axis direction, and the direction along the long side direction of the pixel 30 is referred to as the Y-axis direction. In the present embodiment, the X-axis direction is a direction along the lateral direction of the display screen.

As shown in fig. 3 to 5, two square half pixels 30a (i.e., half of one pixel) are arranged in the Y-axis direction in each pixel 30. The half-pixel 30a constituting each pixel 30 has a plurality of alignment regions (hereinafter, also referred to as "liquid crystal domains") having different alignment orientations of liquid crystal molecules in the liquid crystal layer 13 (see fig. 3 to 5). In the present embodiment, four liquid crystal domains (first domain 31 to fourth domain 34) are formed in the half-pixel 30a by exposing each of the organic films 29 formed on the first substrate 11 and the second substrate 12 from different orientations a plurality of times (see fig. 3 to 5).

Specifically, as shown in fig. 3, in the exposure of each substrate, light is irradiated from the direction P1 to one of the two regions in which the half pixel 30a is divided into two in the Y-axis direction, and light is irradiated from the direction P2 which is the direction opposite to the direction P1 to the other region, with respect to the organic film 29 formed on the first substrate 11. As shown in fig. 4, the organic film 29 formed on the second substrate 12 is irradiated with light from the direction P3 in one of two regions in which the half pixel 30a is divided into two in the X-axis direction, and irradiated with light from the direction P4 in the other region which is the direction opposite to the direction P3. The irradiation directions of light to the organic film 29 formed on the first substrate 11 and the organic film 29 formed on the second substrate 12 are set to be substantially 90 ° different from each other when the first substrate 11 and the second substrate 12 are bonded (see fig. 5). That is, in each liquid crystal domain, the tilt orientation of the liquid crystal molecules present in the vicinity of the first alignment film 22 and the tilt orientation of the liquid crystal molecules present in the vicinity of the second alignment film 23 are different from each other by approximately 90 °. Accordingly, the liquid crystal molecules included in the liquid crystal layer 13 are twisted by approximately 90 ° between the pair of substrates when a voltage is applied, and are vertically aligned when no voltage is applied. When a voltage is applied, the orientations of the first domain 31 to the fourth domain 34, which are obtained by projecting the major axis directions of the liquid crystal molecules present near the center in the thickness direction of the liquid crystal layer 13 onto the first substrate 11, are approximately 225 °, approximately 135 °, approximately 45 °, and approximately 315 ° in this order, respectively (see fig. 5).

The structure of the pixel 30 is not limited to the structure shown in fig. 3 to 5. For example, one pixel 30 may be constituted by arranging half pixels 30a in the lateral direction of the display screen. The number of liquid crystal domains included in the half pixel 30a is not particularly limited, and may be two, for example. In addition, the structure is not limited to the one pixel divided into eight regions, and one pixel may be divided into, for example, four regions. The arrangement of the pixels 30 is not limited to a matrix. The liquid crystal display device 10 has the pixels 30 shown in fig. 3 to 5, and one pixel 30 is divided into eight areas in total, but since the alignment direction of the liquid crystal molecules is four, the liquid crystal display device is in a four-domain RTN mode or a vertically aligned twisted nematic (VERTICAL ALIGNMENT TWISTED NEMATIC, VATN) mode. The four-domain RTN mode liquid crystal display device 10 can be obtained by irradiating the organic film 29 formed on the first substrate 11 with two times of light, and irradiating the organic film 29 formed on the second substrate 12 with two times of light, that is, four times of light in total.

< Method for manufacturing liquid Crystal display device >

Next, a method for manufacturing the liquid crystal display device 10 will be described. The liquid crystal display device 10 can be manufactured by a method including the following film formation step and exposure step.

A film forming step of forming a photosensitive organic film (organic film 29) by applying a liquid crystal aligning agent to a substrate

An exposure step of exposing the organic film 29 through a photomask while relatively moving the substrate on which the organic film 29 is formed with respect to the light source

Hereinafter, each step will be described.

(Film Forming Process)

First, the first substrate 11 and the second substrate 12 are prepared. Then, a liquid crystal aligning agent is applied to each electrode arrangement surface of the first substrate 11 and the second substrate 12, and a coating film is formed on the substrates. In the film forming step, the organic film 29 is formed on at least one of the first substrate 11 and the second substrate 12. In the present embodiment, the organic film 29 is formed on both the first substrate 11 and the second substrate 12. The liquid crystal aligning agent is preferably applied to the substrate by offset printing, flexography, spin coating, roll coater, or inkjet printing.

After the liquid crystal aligning agent is applied, preheating (prebaking) is preferably performed for the purpose of preventing sagging of the applied liquid crystal aligning agent, and the like. The pre-baking temperature is preferably 30-200 ℃, and the pre-baking time is preferably 0.25-10 minutes. Thereafter, calcination (post baking) is performed for the purpose of removing the solvent or the like. The calcination temperature (post-baking temperature) is preferably 80 ℃ to 300 ℃, and the post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the formed coating film is, for example, 0.001 μm to 1 μm.

(Exposure Process)

Then, the organic film 29 formed in the film forming step is subjected to a photo-alignment treatment, and a desired pretilt angle is imparted to the organic film 29. In the case of a homeotropic alignment film, the pretilt angle is, for example, 85 ° to 89.9 °. In the present embodiment, polarized radiation (linear polarization) is irradiated from a direction inclined with respect to the substrate surface to the organic film 29 formed on each substrate surface of the first substrate 11 and the second substrate 12 through the photomask 40 (see fig. 6). As the radiation to be irradiated to the organic film 29, for example, ultraviolet rays and visible rays including light having a wavelength of 150nm to 800nm can be used. Preferably ultraviolet rays containing light having a wavelength of 200nm to 400 nm.

Examples of the light source to be used include a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, and an excimer laser. The irradiation amount of the radiation is preferably 50J/m ²～50,000J/m², more preferably 100J/m ²～2,000J/m². The angle between the irradiation direction of the radiation and the substrate surface is, for example, 30 ° or more and less than 90 °. After the light irradiation, the substrate surface may be washed with water, an organic solvent (e.g., methanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.), or a mixture of these, or the substrate may be heated.

The photo-alignment treatment is preferably performed by scanning exposure for irradiating the organic film 29 with radiation while moving the substrate in a predetermined direction with respect to the light source or moving the light source in a predetermined direction with respect to the substrate. In the present embodiment, the organic film 29 formed by the film forming step is exposed a plurality of times, so that a plurality of liquid crystal domains having different orientations are formed by projecting the major axis directions of the liquid crystal molecules present near the center in the thickness direction of the liquid crystal layer 13 onto the first substrate 11. For example, in the pixels shown in fig. 3 to 5, one half-pixel region is divided into four regions in which alignment directions of liquid crystal molecules are different from each other.

An example of the exposure apparatus 50 and the scanning exposure used in the present embodiment will be described with reference to fig. 6. In fig. 6, an arrow denoted by W indicates a moving direction (scanning direction) of the substrate 38 relative to the light source 36, and an arrow denoted by M indicates a transmission axis direction of the polarizing element 37. The scanning direction W corresponds to a "predetermined moving direction".

The exposure device 50 includes a light source 36, a photomask 40, and a scanner 51. The scanner unit 51 has a mechanism for relatively moving the substrate 38 on which the organic film 29 is formed with respect to the light source 36. Photomask 40 is disposed above substrate 38 with a predetermined gap (proximity gap), and light source 36 is disposed above photomask 40. A plurality of slits 61 are provided in the photomask 40. In fig. 6, only one slit 61 is shown for convenience. The slit 61 corresponds to a "light transmitting portion". In the exposure apparatus 50, the substrate 38 is moved in the scanning direction W relative to the light source 36 by the scanning unit 51, and light is irradiated from the light source 36, whereby the organic film 29 is subjected to scanning exposure via the photomask 40. The light U emitted from the light source 36 is transmitted through the polarizing element 37, and the transmitted light vibrating in the transmission axis direction is emitted from an oblique direction to the organic film 29 formed on the substrate 38 through the slit 61 of the photomask 40.

The substrate 38 may be any one of the first substrate 11 and the second substrate 12. In the present embodiment, the organic film 29 formed on each of the first substrate 11 and the second substrate 12 is irradiated with linearly polarized light by the exposure device 50. By exposing the organic film 29, an oblique orientation (direction S1 in fig. 6) is given to the organic film 29 in the same direction along the scanning direction W. Instead of moving the substrate 38 relative to the light source 36 by the scanner unit 51, a structure in which the light source 36 is moved relative to the substrate 38 may be employed.

In the process of manufacturing the liquid crystal display device 10, the organic film 29 formed on the mother substrate of a large size (for example, G8 size or G10 size) may be exposed in order to efficiently produce the liquid crystal display device 10 of a large screen size. In the example shown in fig. 7, the substrate 38 includes eight substrates 38a (the first substrate 11 or the second substrate 12). It is also impractical, from an equipment or cost standpoint, to use a large exposure apparatus 50 or a large photomask for such a large substrate 38 to expose it at one time.

Therefore, in the present embodiment, a relatively small photomask 40 is used for the substrate 38, and one exposure is performed on a part of the organic film 29 through the photomask 40, and the remaining at least part is repeatedly exposed through the photomask 40. When the entire surface of the organic film 29 is exposed to light at one time by connecting only the relatively small photomask 40 to the substrate 38, a seam between adjacent exposure areas may be easily recognized as a luminance difference due to a difference in exposure conditions (for example, a difference in illuminance between the exposure areas, a positional shift of the mask, or the like), and the luminance difference may be visually recognized as a display unevenness by an observer. Even if the exposure conditions are slightly different, if the brightness is discontinuously changed, the discontinuous brightness change is easily visually recognized as display unevenness by the human eye. On the other hand, by providing a portion to be repeatedly exposed between adjacent exposure regions, abrupt changes in brightness at the joint of the photomask 40 are suppressed, and thus, the occurrence of display unevenness can be reduced.

In the present embodiment, the substrate surface is exposed using a plurality of photomasks 40 from the viewpoint of improving the production efficiency. Specifically, as shown in fig. 7, the plurality of photomasks 40 are arranged in a direction intersecting (preferably orthogonal to) the scanning direction W and along the intersecting direction V, which is the direction along the substrate surface. By linearly moving the substrate 38 in the scanning direction W with respect to the plurality of photomasks 40, the organic film 29 is exposed from one end to the other end in the scanning direction W of the substrate 38 by one relative movement of the substrate 38 with respect to the light source 36. At this time, a part of the region of the organic film 29 is subjected to one exposure, and the remaining region is subjected to repeated exposure.

The arrangement of the plurality of photomasks 40 will be described with reference to fig. 6 and 7. The exposure device 50 is provided with an exposure unit 52 in which the light source 36 and the photomask 40 are integrated. The exposure unit 52 includes, as the photomask 40, a first photomask 41 and a second photomask 42, the first photomask 41 being disposed on the same line extending in the intersecting direction V, and the second photomask 42 being disposed further rearward than the first photomask 41 when viewed in the scanning direction W from the substrate 38 and on the same line extending in the intersecting direction V. The first photomask 41 and the second photomask 42 are arranged adjacent to each other in the intersecting direction V, and a part of each of the adjacent photomasks 40 overlaps with each other when viewed in the scanning direction W. The exposure unit 52 is provided with a number of light sources 36 (i.e., a plurality of light sources) corresponding to the photomasks 40, and each light source 36 is integrated with each photomask 40.

In the exposure apparatus 50, the scanning unit 51 moves the substrate 38 relative to the exposure unit 52 fixed at a predetermined position, and thereby moves the substrate 38 relative to the exposure unit 52. As a result, as shown in fig. 7, the organic film 29 on the substrate 38 includes a non-overlapping region 29a where one exposure is performed through the first photomask 41 or the second photomask 42, and an overlapping region 29b (a hatched portion in fig. 7) where the repeated exposure is performed through the first photomask 41 and the second photomask 42. In the overlap region 29b, light is irradiated through the joint 43 between the first photomask 41 and the second photomask 42.

In the case of obtaining the liquid crystal display device 10 after alignment division, the organic film 29 is subjected to multiple exposure from different directions. For example, the half pixel 30a having four liquid crystal domains 31 to 35 shown in fig. 3 to 5 can be obtained by performing scanning exposure twice on the organic film 29 formed on the first substrate 11 and the organic film 29 formed on the second substrate 12, respectively. Specifically, in the case of exposing the substrate 38 for obtaining the first substrate 11, first, the slit 61 of the photomask 40 is aligned with the half pixel 30a (more specifically, the region in which the half pixel 30a is divided into half of two parts in the Y-axis direction). Next, polarized ultraviolet rays (first scanning) are irradiated from a direction inclined with respect to the substrate surface through the first photomask 41 and the second photomask 42 while the substrate 38 is moved in the Y-axis direction. By the first scanning, a liquid crystal aligning ability is given to a region of half of the half pixel 30a divided into two in the Y-axis direction. At this time, the pixels 30 included in the overlapping region 29b overlap with each other, and the exposure through the first photomask 41 and the exposure through the second photomask 42 are performed. The total amount of exposure to the pixels 30 included in the overlapping region 29b (i.e., the total amount of exposure to the first photomask 41 and the exposure to the second photomask 42) is, for example, 80% to 100% with respect to the exposure to the pixels 30 included in the non-overlapping region 29 a. In the present embodiment, the total amount of exposure to the pixels 30 included in the overlapping region 29b is set to be equal to (approximately 100%) the amount of exposure to the pixels 30 included in the non-overlapping region 29 a.

Next, the substrate 38 exposed by the first scan is rotated 180 ° in the plane, and the unexposed area of the half-pixels 30a that is not exposed by the first scan is aligned with the slit 61 of the photomask 40. Further, since the half pixel 30a is square, the length in the X-axis direction of the half pixel 30a is the same as the length in the Y-axis direction. Then, as in the first scan, polarized ultraviolet rays are irradiated from a direction inclined with respect to the substrate surface through the first photomask 41 and the second photomask 42 while the substrate 38 is moved in the Y-axis direction (second scan). As a result, as shown in fig. 3, on the first substrate 11, a liquid crystal alignment film (first alignment film 22) having a tilt orientation of liquid crystal molecules in the Y-axis direction in an antiparallel direction to each other is formed in two regions that divide the half pixel 30a into two in the Y-axis direction.

The above description has been made of the method in which the same exposure unit 52 is used for the first and second scans, the substrate 38 is rotated 180 ° in the plane after the first scan is performed to expose the substrate 38, and then the second scan is performed to expose the unexposed region, but the scanning exposure method is not limited to the above. For example, the first scan and the second scan may be performed by different exposure units. Specifically, in the exposure apparatus, a first scanning exposure unit (first exposure unit) whose light irradiation direction is a predetermined direction and a second scanning exposure unit (second exposure unit) whose light irradiation direction is antiparallel to the first exposure unit are provided. After the first scanning by the first exposure means or during the first scanning, the unexposed area of the half-pixel 30a that has not been exposed by the first scanning is irradiated with polarized ultraviolet rays (second scanning) from a direction inclined with respect to the substrate surface by the second exposure means. In this method, a large number of scanning light sources or photomasks are required, but the time required for the exposure process can be shortened.

The exposure of the substrate 38 corresponding to the second substrate 12 is basically the same as that of the first substrate 11 except that the scanning direction is the X-axis direction. By performing scanning exposure twice on the substrate 38 corresponding to the second substrate 12, as shown in fig. 4, a liquid crystal alignment film (second alignment film 23) in which the tilt directions of liquid crystal molecules are antiparallel to each other in the X-axis direction is formed on the second substrate 12 in two regions in which the half pixel 30a is divided into two in the X-axis direction. Then, the first substrate 11 and the second substrate 12 are arranged with a predetermined interval (cell gap) provided so as to face each other with the liquid crystal alignment films, and the liquid crystal layer 13 is provided between the first substrate 11 and the second substrate 12, whereby the pixel 30 having four liquid crystal domains can be obtained as shown in fig. 5.

< Photomask >

Next, the structure (particularly, mask pattern) of the photomask 40 will be described in detail. The photomask 40 includes a plurality of slits 61 and light shielding portions 62 provided between the slits 61, and the slits 61 and the light shielding portions 62 are alternately arranged. As shown in fig. 7 and 8, the first photomask 41 and the second photomask 42 each have a non-overlapping region 45 where the first photomask 41 and the second photomask 42 do not overlap when viewed in the scanning direction W, and an overlapping region 46 where the first photomask 41 and the second photomask 42 overlap when viewed in the scanning direction W. Fig. 8 shows a first photomask 41 and a second photomask 42 in portions corresponding to a region G in fig. 7. The photomask pattern other than the portion corresponding to the region G also has the same photomask pattern as the portion corresponding to the region G.

The non-repeated region 45 is a region of the photomask 40 corresponding to a portion of the organic film 29 subjected to one exposure. As shown in fig. 8, a plurality of slits 61a having the same opening area are provided in the non-overlapping region 45, and light shielding portions 62a are arranged between the slits 61 a. The slits 61a have a rectangular shape (more specifically, a rectangular shape) extending in the scanning direction W, and are arranged at the same intervals (i.e., equal intervals) as the pixel pitch Px in the direction along the intersecting direction V. The length of the slit 61a in the intersecting direction V, that is, the slit width Lx is, for example, approximately half ±α (μm) of the pixel pitch Px. The length Ly of the slit 61a in the scanning direction W is a predetermined reference length Lyc, for example, about 40 mm.

The repeated region 46 is a region of the photomask 40 corresponding to a portion of the organic film 29 where repeated exposure is performed. As shown in fig. 8, a plurality of slits 61b having different opening areas are provided in the overlap region 46, and light shielding portions 62b are arranged between the slits 61b. The slits 61b are rectangular, and are arranged at the same intervals (i.e., equal intervals) as the pixel pitch Px in the direction along the intersecting direction V. The "plurality of slits having different opening areas" is not limited to a structure that does not include slits having the same opening area, and may include slits 61b having the same opening area as long as at least a part of the slits 61b have different opening areas. At least a part of the slits 61 (slits 61 b) arranged in the repeating region 46 has a smaller opening area than the slits 61 (slits 61 a) arranged in the non-repeating region 45. The opening area of the slit 61b may be variable by adjusting the length Ly, for example.

The first photomask 41 and the second photomask 42 may have the repetition region 46 only at one end portion or may have the repetition region 46 at both end portions in the intersecting direction V, depending on the position in the intersecting direction V with respect to the substrate 38. In each photomask 40, the photomask 40 disposed at the outer edge portion in the intersecting direction V of the substrate 38 may have the overlap region 46 at least one of the mask ends. The photomask 40 disposed at the central portion in the intersecting direction V of the substrate 38 may have the overlap region 46 at each of the two end portions in the intersecting direction V, and the joint portion 43 may be formed between the adjacent photomask 40.

Here, in the overlapping region 29b where light is irradiated through the joint portion 43, a luminance difference is easily generated between the non-overlapping region 29a by repeated exposure. Regarding the change in luminance of the overlapping region 29b with respect to the non-overlapping region 29a, the inventors prepared an evaluation unit produced by one exposure to the organic film 29 and an evaluation unit produced by repeated exposure, and studied the luminance of the evaluation unit in comparison. As a result, it was found that, in the overlapping region 29b, when the exposure amounts of the respective times in the repeated exposure are close, the luminance change becomes large with respect to the non-overlapping region 29 a.

Fig. 9 shows the results of evaluating the brightness of the evaluation unit produced by one exposure to the organic film 29 and the evaluation unit produced by repeated exposure. In the luminance evaluation of fig. 9, an evaluation unit was prepared and evaluated by the following method. First, a transparent electrode is formed on a glass substrate, a liquid crystal alignment agent is applied to the transparent electrode, and then a heat treatment is performed to form a photosensitive organic film (organic film 29). Then, polarized ultraviolet rays are irradiated from a direction inclined with respect to the substrate surface to the photosensitive organic film formed on the glass substrate, and a liquid crystal alignment property in one direction is imparted thereto to form a photo-alignment film. The same procedure was performed to prepare two glass substrates on which the photo-alignment film was formed. Two substrates were bonded via a spacer and a sealing material, and a liquid crystal material having negative dielectric anisotropy was injected between the substrates, to prepare a vertically aligned evaluation cell. The light quantity of the transmitted light of the evaluation unit was measured with the evaluation unit sandwiched by polarizing plates and a voltage of 2.3V was applied between the transparent electrodes.

A total of four units are produced as evaluation units by applying any one of the following conditions (1) to (4) different in the number of exposures and the amount of exposure to the organic film 29. The irradiation directions of the light are all the same.

(1) Polarized ultraviolet rays of a reference exposure amount are irradiated once from a direction inclined with respect to the substrate surface

(2) After the polarized ultraviolet light having an exposure amount of 80% with respect to the reference exposure amount is irradiated once from the direction inclined with respect to the substrate surface, the polarized ultraviolet light having an exposure amount of 20% with respect to the reference exposure amount is irradiated once from the direction inclined with respect to the substrate surface

(3) After the polarized ultraviolet light having an exposure amount of 50% with respect to the reference exposure amount is irradiated once from the direction inclined with respect to the substrate surface, the polarized ultraviolet light having an exposure amount of 50% with respect to the reference exposure amount is irradiated once from the direction inclined with respect to the substrate surface

(4) After the polarized ultraviolet light having an exposure amount of 20% with respect to the reference exposure amount is irradiated once from the direction inclined with respect to the substrate surface, the polarized ultraviolet light having an exposure amount of 80% with respect to the reference exposure amount is irradiated once from the direction inclined with respect to the substrate surface

Regarding the evaluation result, the light quantity of the transmitted light of the evaluation unit produced by the one exposure under the reference exposure (condition (1)) was set to 100, and the light quantity of the transmitted light of each evaluation unit was represented by an index, and as a result, 100.6% in condition (2), 102.0% in condition (3) and 100.6% in condition (4) (see fig. 9). Based on the results of the brightness evaluation, it was found that when the repeated exposure was performed under the condition (3), the brightness became higher than when the repeated exposure was performed under the condition (2) or the condition (4), and the brightness change with respect to the one exposure was remarkably exhibited.

The reason why the above-described luminance change occurs is not yet clear, but it is assumed that a reaction different from the non-overlapping region 29a where the exposure is not overlapped (specifically, a reaction in which the pretilt angle of the liquid crystal molecules of the evaluation unit becomes smaller) occurs on the surface of the organic film 29 in the overlapping region 29b where the repeated exposure is performed. More specifically, it is considered that the reaction on the film surface accompanying the oblique irradiation of polarized ultraviolet rays and the chemical reaction proportional to the exposure amount occurring during the light irradiation in either one exposure or the repeated exposure are related to the chemical reaction occurring simply not proportional to the exposure amount due to the relaxation after the light irradiation is completed. Here, it is considered that the reaction occurring due to the relaxation after the completion of the light irradiation is only one time in the case of one exposure, whereas the reaction occurring due to the relaxation after the completion of the light irradiation is multiple times in the case of repeated exposure, and the influence of the respective reactions occurring due to the relaxation after the completion of each light irradiation becomes large in the case of multiple exposure by polarized ultraviolet rays exceeding a certain exposure amount. As a result, it is considered that when the polarized ultraviolet light exceeding a certain exposure amount is subjected to multiple exposure, the photo-alignment film undergoes a pretilt angle change exceeding the total amount of the exposure amounts added up, and the result appears as a brightness change. This is merely to be understood, and the present invention is not limited thereto.

Based on the above-described findings, in the present embodiment, the slit 61b provided in the repetitive region 46 of the photomask 40 is set to be the first slit 63 having an opening area of 75% or more and 100% or less with respect to the opening area of the slit 61a (hereinafter, also referred to as "reference area Sc") provided in the non-repetitive region 45 or the second slit 64 having an opening area of more than 0% and 25% or less with respect to the reference area Sc. This prevents the brightness from greatly appearing in the overlapping region 29b due to the approach of the exposure amounts of the respective times, and suppresses the degradation of the display quality caused by the local brightening of the overlapping region 29 b. In addition, by a simple method of forming the slit 61b of the overlap region 46 as a photomask pattern including the first slit 63 and the second slit 64, it is also advantageous in that the influence of the variation in illuminance of the light source 36 or the material of the liquid crystal alignment film can be suppressed, and the variation in brightness in the joint portion 43 can be suppressed.

The opening area of the first slit 63 may be in the range of 75% to 100%. The opening area of the first slit 63 is preferably 80% or more in view of sufficiently suppressing the partial brightness on the display screen corresponding to the overlap region 29 b. In addition, from the viewpoint of suppressing the variation in luminance in the whole of the overlap region 29b, the opening area of the first slit 63 is preferably less than 100%, more preferably 99% or less, and still more preferably 98% or less.

The opening area of the second slit 64 may be in the range of more than 0% and 25% or less. The opening area of the second slit 64 is preferably 1% or more, more preferably 2% or more, from the viewpoint of suppressing the variation in luminance in the entire overlapping region 29 b. The opening area of the second slit 64 is preferably 20% or less. In addition, the plurality of first slits 63 disposed in the repeating region 46 may all have the same opening area, or may have at least a portion having different opening areas. In addition, the plurality of second slits 64 disposed in the repeating region 46 may all have the same opening area, or may have at least a part of the opening areas different from each other.

The slit width Lx of the first slit 63 and the second slit 64 is the same as the slit 61a disposed in the non-repetitive region 45, and is, for example, approximately half ±α (μm) of the pixel pitch Px. The first slit 63 and the second slit 64 have the same length Ly as the slit 61a or shorter than the slit 61a, and the shorter the length Ly, the smaller the opening area of the slit 61.

The configuration of the slit 61b in the repetition region 46 will be described in more detail using fig. 8. As shown in fig. 8, in each of the repetition areas 46 of the first photomask 41 and the second photomask 42, the first slit 63 and the second slit 64 are arranged at predetermined intervals corresponding to the pixel pitch Px along the intersecting direction V. When viewed in the scanning direction W, the first photomask 41 and the second photomask 42 are positioned such that the first slit 63 disposed in one of the repetition areas 46 of the first photomask 41 and the second photomask 42 and the second slit 64 disposed in the repetition area 46 of the other photomask are disposed on the same line (on the straight line Ey in fig. 8) extending in the scanning direction W.

In the example shown in fig. 8, the length Ly of the first slit 63 is 75% of the reference length Lyc, and has an opening area of 75% with respect to the reference area Sc. The length Ly of the second slit 64 is 25% of the reference length Lyc, and has an opening area of 25% with respect to the reference area Sc. The sum of the opening areas of the two slits arranged on the straight line Ey in the first photomask 41 and the second photomask 42 is equal to the reference area Sc. For example, based on the center line Ec of the repetitive region 46 extending in the scanning direction W, the second slit 64 is disposed in the first photomask 41 and the first slit 63 is disposed in the second photomask 42 at the tenth position in the direction from the center line Ec toward the non-repetitive region 45 of the first photomask 41.

In each of the repetition areas 46 of the first photomask 41 and the second photomask 42, a second slit 64 is disposed at a position symmetrical to the first slit 63 about the center line Ec of the repetition area 46, and the first slit 63 is disposed at a position symmetrical to the second slit 64. With this arrangement, the variation in the slit opening area in the joint portion 43 of the first photomask 41 and the second photomask 42 can be suppressed by a simple method. This can suppress occurrence of uneven brightness variation in the entire cross direction V of the joint portion 43, and further suppress uneven display due to repeated exposure. In the example shown in fig. 8, in the repeating region 46 of the first photomask 41, the second slit 64 is disposed at the third in the direction from the center line Ec toward the non-repeating region 45, and the first slit 63 is disposed at the third in the direction from the center line Ec toward the mask end 44. In addition, a first slit 63 is disposed at a fifteenth position from the center line Ec toward the non-repeating region 45, and a second slit 64 is disposed at a fifteenth position in a direction from the center line Ec toward the mask end 44.

In each of the repeating regions 46, the slits 61b (i.e., the first slits 63 and the second slits 64) are arranged so that the sum Σs of the opening areas of the slits 61b included in the region of the predetermined length Hx along the intersecting direction V tends to increase from the mask end 44 toward the non-repeating region 45. That is, the first slit 63 and the second slit 64 are combined in each of the repeating regions 46 so that the exposure amount irradiated to the organic film 29 through each slit 61b shows an increasing tendency from the mask end 44 toward the non-repeating region 45. Thus, the luminance can be continuously changed in the entirety of the overlap region 29b, and the luminance change at the transition portion from the overlap region 29b to the non-overlap region 29a can be made smoother. As a result, the boundary portion between the overlapping region 29b and the non-overlapping region 29a can be more effectively suppressed from being visually recognized on the display screen by the observer. The method of changing the sum Σs of the opening areas is not particularly limited, and for example, linear change, trigonometric change, or the like may be employed.

The predetermined length Hx is set to a value (=pixel pitch px×the number of pixels Nx, nx being 2 or more, for example) corresponding to the number of pixels 30. For example, in the example shown in fig. 8, when the number Nx of pixels is 5, the sum Σs of the opening areas of the slits included in the region of the predetermined length Hx (region of Hx1 in fig. 8) in the end portion 44 of the first photomask 41 is "(reference area sc×0.75×1) + (reference area sc×0.25×4) =reference area sc×1.75). In addition, the sum Σs of the opening areas of the slits included in the region of the predetermined length Hx (region Hx2 in fig. 8) in the center portion of the repetition region 46 of the first photomask 41 is "(reference area sc×0.75×2) + (reference area sc×0.25×3) =reference area sc×2.25). The sum Σs of the opening areas of the slits included in the region of the predetermined length Hx (region of Hx3 in fig. 8) in the adjacent portion to the non-repeating region 45 in the repeating region 46 of the first photomask 41 is "(reference area sc×0.75×4) + (reference area sc×0.25×1) =reference area sc×3.25). That is, in the repetition region 46 of the first photomask 41, the sum Σs of the opening areas shows a tendency to increase from the mask end 44 toward the non-repetition region 45 of "1.75→2.25→3.25". The same is true for the repeated areas 46 of the second photomask 42.

In each of the repeating regions 46, the sum Σs of the opening areas shows an increasing tendency from the mask end 44 toward the non-repeating region 45 according to the degree of discrete density of the first slits 63. That is, in each of the repeating regions 46, the first slits 63 are closely arranged from the mask end 44 toward the non-repeating region 45. For example, in the example shown in fig. 8, the number of first slits 63 included in the region Hx1 is "1", the number of first slits 63 included in the region Hx2 is "2", the number of first slits 63 included in the region Hx3 is "4", and the number of first slits 63 included per unit area (i.e., the frequency of the first slits 63) increases from the mask end 44 toward the non-repeating region 45. The variation in the opening area in the intersecting direction V can be made smoother by a simple method such as design of the arrangement of the slits 61b, depending on the degree of discrete density of the first slits 63. As a result, brightness unevenness on the display screen due to repeated exposure can be suppressed without depending on a complicated method.

In the example shown in fig. 8, in each of the repeated regions 46 of the first photomask 41 and the second photomask 42, the second slit 64 is disposed alone at the boundary 47 between the non-repeated regions 45, and the first slit 63 is disposed alone at the mask end 44. Even in the case where the second slit 64 is disposed in the boundary portion 47, if the second slit 64 is disposed alone, abrupt changes in the slit opening area in the boundary portion 47 can be suppressed. Therefore, even in this case, abrupt luminance changes between the overlapping region 29b and the non-overlapping region 29a can be suppressed, and the occurrence of display unevenness in the joint portion 43 can be suppressed.

In the present embodiment described above, in view of the fact that the brightness change becomes large in the overlap region 29b when the exposure amounts of the respective repeated exposures are close, the slit 61b disposed in the repetition region 46 of the photomask 40 is set to the first slit 63 having an opening area of 75% to 100% with respect to the reference area Sc or the second slit 64 having an opening area of more than 0% to 25% with respect to the reference area Sc. This can suppress the local brightening of the overlapping region 29b due to the approaching of the exposure amounts in each time in the overlapping region 29b, and as a result, the defective display of the liquid crystal display device 10 can be suppressed.

In the present embodiment, when viewed in the scanning direction W, the first slit 63 disposed in the repetition region 46 of one of the first photomask 41 and the second photomask 42 and the second slit 64 disposed in the repetition region 46 of the other photomask are disposed on a straight line Ey. This can suppress the occurrence of variation in brightness due to variation in the exposure amount in the entire overlap region 29b, and as a result, the occurrence of display unevenness in the entire overlap region 29b can be suppressed. Further, the variation in the exposure amount at the boundary portion between the non-overlapping region 29a and the overlapping region 29b can be smoothed, and the joint portion 43 can be suppressed from being visually recognized on the display screen.

In particular, by making the opening area of the first slit 63 smaller than 100%, the first slit 63 and the second slit 64 can be arranged on the straight line Ey, and the sum of the opening areas of the first slit 63 and the second slit 64 arranged on the straight line Ey can be made equal to the reference area Sc. This makes it possible to make the change in the exposure amount of the boundary portion between the non-overlapping region 29a and the overlapping region 29b smoother, and effectively suppress the joint portion 43 from being visually recognized on the display screen.

Further, in the present embodiment, the slits 61b are arranged in the respective repeating regions 46 of the first photomask 41 and the second photomask 42 so that the sum Σs of the opening areas tends to increase from the mask end 44 toward the non-repeating region 45 according to the degree of discrete density of the first slits 63. Therefore, the effect of suppressing the increase in luminance due to the arrangement of the first slit 63 and the second slit 64 can be obtained, and the variation in the opening area of the slit 61b can be smoothed in the boundary portion between the joint portion 43 and the non-repetitive region 45 and the joint portion 43 as a whole.

The present embodiment is not limited to the above-described embodiment, and may be implemented by the following embodiments, for example.

In the above embodiment, the opening area of the first slit 63 is 75% of the reference area Sc, and the opening area of the second slit 64 is 25% of the reference area Sc, but the opening area of the first slit 63 may be 75% to 100% of the reference area Sc, and the opening area of the second slit 64 may be 0% to 25% of the reference area Sc. For example, as shown in fig. 10, the opening area of the first slit 63 may be 90% of the reference area Sc, and the opening area of the second slit 64 may be 10% of the reference area Sc. In view of design easiness and light transmission limit, the opening area of the second slit 64 is preferably 1% to 25% of the reference area Sc, more preferably 2% to 25%.

In the above embodiment, the opening areas of all the first slits 63 are made the same, and the opening areas of all the second slits 64 are made the same, but as long as the opening area of the first slits 63 is 75% or more and 100% or less of the reference area Sc and the opening area of the second slits 64 is 0% or more and 25% or less than the reference area Sc, the first slits 63 and the second slits 64 may each include slits having different opening areas. For example, a slit having an opening area of 80% of the reference area Sc and a slit having an opening area of 90% of the reference area Sc may be included as the first slit 63. The second slit 64 may similarly include a slit having an opening area of 20% of the reference area Sc and a slit having an opening area of 10% of the reference area Sc.

In the above embodiment, the total of the opening areas of the two slits arranged on the straight line Ey is made equal to the reference area Sc (i.e., 100% with respect to the reference area Sc) in the respective repetition areas 46 of the first photomask 41 and the second photomask 42, but the present invention is not limited to the above configuration. For example, the total of the opening areas of the two slits arranged on the straight line Ey is, for example, 80% to 99% of the reference area Sc. Instead of having the configuration in which the total of the opening areas of the two slits arranged on the straight line Ey is the same in the entire joint 43, the total of the opening areas of the two slits arranged on the straight line Ey may be variable in the joint 43. For example, the total of the opening areas of the two slits arranged on the straight line Ey may be linearly or trigonometrically reduced from the end portions of the joint portion 43 toward the center portion.

In the above embodiment, the second slit 64 is disposed at a position symmetrical to the first slit 63 and the first slit 63 is disposed at a position symmetrical to the second slit 64, but the present invention is not limited to this, and the first slit 63 may be disposed at a position symmetrical to the first slit 63 with the center line Ec as an axis. The second slit 64 may be disposed at a position symmetrical to the second slit 64 with respect to the center line Ec.

Second embodiment

Next, a second embodiment of the manufacturing method of the present disclosure will be described. In the second embodiment, the arrangement (photomask pattern) of the slits 61 in the joint portion 43 of the photomask 40 is different from that in the first embodiment. In the following description, the same configuration as in the first embodiment will be omitted, and the description will be mainly directed to differences from the first embodiment.

Fig. 11 shows a structure of a photomask 40 in the second embodiment. The repeating region 46 of each of the first photomask 41 and the second photomask 42 of the present embodiment has a first section F1 adjacent to the non-repeating region 45 and a second section F2 including the mask end 44. The first slit 63 is disposed in the first section F1, and the second slit 64 is not disposed. In the second section F2, the second slit 64 is disposed, and the first slit 63 is not disposed. In the example shown in fig. 11, of the two sections divided by the center line Ec, the region including the boundary portion 47 of the non-overlapping region 45 is the first section F1, and the region including the mask end portion 44 is the second section F2. By disposing the first section F1 including the first slit 63 at the boundary portion of the non-overlapping region 45 in the joint portion 43 between the first photomask 41 and the second photomask 42, the exposure amount to the organic film 29 can be continuously changed at the boundary portion between the non-overlapping region 29a and the overlapping region 29 b. This effectively suppresses the brightness variation in the overlapping region 29b from being visually recognized as display unevenness.

A plurality of first slits 63 are arranged in the first section F1. The plurality of first slits 63 arranged in the first section F1 preferably have opening areas each of which decreases in a direction away from the non-overlapping region 45. Thus, the exposure amount at the boundary portion between the non-overlapping region 29a and the overlapping region 29b can be continuously changed along the intersecting direction V, and the luminance change in the overlapping region 29b can be more effectively suppressed. In the example shown in fig. 11, in the first section F1, the opening area of the first slit 63 gradually decreases (preferably monotonically decreases) from 99% to 75% of the reference area Sc by changing the length Ly of each slit. The length Ly of the first slit 63 from the center line Ec is 75% of the reference length Lyc, and the opening area is 75% of the reference area Sc. The variation in the reduction of the opening area of the first slit 63 in the first section F1 may be linear or trigonometric.

A plurality of second slits 64 are arranged in the second section F2. The plurality of second slits 64 arranged in the second section F2 preferably have opening areas that decrease in the direction toward the mask end 44. Accordingly, the opening areas of the two slits 61 arranged on the straight line Ey in the joint 43 can be adjusted to a desired range while continuously changing the exposure amount at the boundary portion between the non-overlapping region 29a and the overlapping region 29b along the intersecting direction V. As a result, the luminance change is less likely to occur in the entire joint portion 43. In the example shown in fig. 11, the length Ly of the second slit 64 disposed first from the center line Ec in the second section F2 is 25% of the reference length Lyc, and the opening area is 25% of the reference area Sc. In the second section F2, the opening area of the second slit 64 gradually decreases (preferably monotonously decreases) from 25% of the reference area Sc in the direction from the center line Ec toward the mask end 44. The variation in the decrease in the opening area of the second slit 64 in the second section F2 may be linear or trigonometric.

The second embodiment described above exhibits the effects corresponding to the same configuration as the first embodiment. In addition, according to the second embodiment, since the plurality of first slits 63 are arranged in the first section F1 adjacent to the non-overlapping region 45 in the joint 43, the exposure amount at the boundary portion between the non-overlapping region 29a and the overlapping region 29b can be continuously changed along the intersecting direction V. This effectively suppresses the occurrence of a sharp luminance change in the overlap region 29 b.

In particular, in the first section F1, the exposure amount at the boundary portion between the non-overlapping region 29a and the overlapping region 29b can be continuously and smoothly changed by decreasing the opening area of the first slit 63 in the direction away from the non-overlapping region 45. This can more effectively suppress the occurrence of abrupt luminance changes in the overlap region 29 b.

In the above embodiment, the opening area of the first slit 63 is gradually reduced toward 75% of the reference area Sc and the opening area of the second slit 64 is gradually reduced from 25% of the reference area Sc in the first section F1, but the lower limit of the opening area of the first slit 63 and the upper limit of the opening area of the second slit 64 are not limited to the above. For example, as shown in fig. 12, the first slit 63 may be configured such that the length Ly gradually decreases toward 90% of the reference length Lyc, thereby gradually decreasing the opening area toward 90% of the reference area Sc. At this time, the second slit 64 may be formed such that the opening area is gradually reduced from 10% of the reference area Sc by gradually reducing the length Ly from 10% of the reference length Lyc.

In the second embodiment, a decreasing section in which the opening area of the first slit 63 gradually decreases in the direction away from the non-overlapping region 45 and a constant section in which the opening area of the first slit 63 is constant may be provided in the first section F1. The number or combination of the reduced sections and the fixed sections in the first section F1 is not particularly limited. For example, a decreasing section may be disposed adjacent to the non-repeating region 45 in the first section F1, and a constant section may be disposed adjacent to the decreasing section. Further, the decreasing section, the constant section, and the decreasing section may be arranged in this order in a direction from the non-overlapping region toward the center line Ec.

Third embodiment

Next, a third embodiment of the manufacturing method of the present disclosure will be described. In the third embodiment, the arrangement (photomask pattern) of the slits 61 in the joint portion 43 of the photomask 40 is different from the first embodiment and the second embodiment. Specifically, the photomask 40 according to the third embodiment has a third section F3 provided between the first section F1 and the second section F2 in addition to the first section F1 and the second section F2 in the second embodiment. In the following description, the same configuration as in the first and second embodiments will be omitted, and the differences from the first and second embodiments will be mainly described.

Fig. 13 shows a structure of a photomask 40 according to a third embodiment. The repeating region 46 of each of the first photomask 41 and the second photomask 42 of the present embodiment has a first section F1 adjacent to the non-repeating region 45 and a second section F2 including the mask end 44. In the example shown in fig. 13, of the two sections divided by the center line Ec, a part of the region including the boundary 47 of the non-overlapping region 45 becomes the first section F1, and a part of the region including the mask end 44 becomes the second section F2. The length Ly or the arrangement of the slit 61 in the first section F1 and the second section F2 is the same as that of the second embodiment.

The third section F3 is provided between the first section F1 and the second section F2 in the joint 43. A plurality of first slits 63 are arranged in the third section F3. In the example shown in fig. 13, the third section F3 has the same photomask pattern as the repetitive region 46 in the first embodiment.

Specifically, in the third section F3, the slits 61b are arranged at the same intervals (i.e., equal intervals) as the pixel pitch Px in the direction along the intersecting direction V. In the third section F3, the first slit 63 and the second slit 64 are arranged as slits 61b. The length Ly of the first slit 63 is 75% of the reference length Lyc, and has an opening area of 75% with respect to the reference area Sc. The length Ly of the second slit 64 is 25% of the reference length Lyc, and has an opening area of 25% with respect to the reference area Sc. In the first photomask 41 and the second photomask 42, the sum of the opening areas of the two slits arranged on the straight line Ey is equal to the reference area Sc. Further, in the third section F3 of each of the first photomask 41 and the second photomask 42, the second slit 64 is disposed at a position symmetrical to the first slit 63 about the center line Ec of the overlap region 46, and the first slit 63 is disposed at a position symmetrical to the second slit 64.

In the third section F3, the sum Σs of the opening areas of the slits 61b included in the region of the predetermined length Hx shows a tendency to increase in the direction from the second section F2 toward the first section F1, depending on the degree of discrete density of the first slits 63. That is, in the third section F3, the first slits 63 are closely arranged in the direction from the second section F2 toward the first section F1. The increase change in the opening area of the slit 61b in the third section F3 may be linear or trigonometric. In the example shown in fig. 13, in the third section F3, the first slits 63 and the second slits 64 are arranged such that the slits 61b including the first slits 63 and the second slits 64 are equally spaced and the number of the first slits 63 included per unit area (that is, the frequency of the first slits 63) increases.

The third embodiment described above exhibits the effects corresponding to the same configuration as the first embodiment. In the third embodiment, the photomask 40 is provided with a third section F3 between the first section F1 and the second section F2 in addition to the first section F1 and the second section F2. In the third section F3, the first slits 63 are closely arranged in the direction from the second section F2 toward the first section F1, so that the effect of suppressing the increase in luminance due to the arrangement of the first slits 63 can be obtained, and the variation in the opening area of the slits 61b can be smoothed in the joint portion 43. Further, since the first section F1 is provided at a position adjacent to the non-overlapping region 45 in the joint 43, the change in the exposure amount in the boundary portion between the non-overlapping region 29a and the overlapping region 29b can be made continuous, and the occurrence of a rapid luminance change in the overlapping region 29b can be effectively suppressed.

In the above embodiment, the opening area of the first slit 63 is gradually reduced toward 75% of the reference area Sc in the first section F1, the opening area of the second slit 64 is gradually reduced from 25% of the reference area Sc, the opening area of the first slit 63 in the third section F3 is 75% of the reference area Sc, and the opening area of the second slit 64 is 25% of the reference area Sc, but the opening area of the first slit 63 and the opening area of the second slit 64 are not limited to the above. For example, as shown in fig. 14, the opening area of the first slit 63 is set to 90% or more of the reference area Sc by making the length Ly not less than 90% of the reference length Lyc, and the opening area of the second slit 64 may be set to 10% or less of the reference area Sc by making the length Ly not more than 10% of the reference length Lyc with respect to the second slit 64.

In the third embodiment, a decreasing section in which the opening area of the first slit 63 gradually decreases in the direction away from the non-overlapping region 45 and a constant section in which the opening area of the first slit 63 is constant may be provided in the first section F1. In the second section F2, a constant section where the opening area of the second slit 64 is constant and a decreasing section where the opening area of the second slit 64 gradually decreases toward the mask end 44 may be provided.

Fourth embodiment

Next, a fourth embodiment of the manufacturing method of the present disclosure will be described. In the fourth embodiment, the arrangement (photomask pattern) of the slits 61 in the joint portion 43 of the photomask 40 is different from the first to third embodiments. Specifically, the photomask 40 of the fourth embodiment has the first section F1, the second section F2, and the third section F3 in the respective repetition areas 46 of the first photomask 41 and the second photomask 42, as in the third embodiment. In the photomask 40 according to the fourth embodiment, the third section F3 is different from the third embodiment in that the first slit 63 is provided but the second slit 64 is not provided, and in that the slits 61b are not arranged at equal intervals. In the following description, the same configuration as in the first to third embodiments will be omitted, and the description will be focused on differences from the first to third embodiments.

Fig. 15 shows a structure of a photomask 40 according to a fourth embodiment. The first slit 63 disposed in the third section F3 has the same length Ly as the reference length Lyc and the opening area as the reference area Sc as the slit 61a disposed in the non-overlapping region 45. In the third section F3, the distribution density of the first slits 63 is changed in the intersecting direction V, whereby the first slits 63 are closely arranged in the direction from the second section F2 toward the first section F1. Thus, the sum Σs of the opening areas of the slits 61b included in the region of the predetermined length Hx shows a tendency to increase in the direction from the second section F2 toward the first section F1. When viewed in the scanning direction W, the first slit 63 is disposed on one of the first photomask 41 and the second photomask 42, and the light shielding portion 62b is disposed on the other photomask, on the straight line Ey.

According to the mask pattern of the photomask 40 of the fourth embodiment, since the first slits 63 are closely arranged in the direction from the second section F2 toward the first section F1 in the third section F3, the effect of suppressing the rise in luminance due to the arrangement of the first slits 63 can be obtained, and the variation in the opening area of the slits 61b can be smoothed in the joint portion 43. Further, since the first section F1 is provided at a position adjacent to the non-overlapping region 45 in the joint portion 43, the change in the exposure amount in the boundary portion between the non-overlapping region 29a and the overlapping region 29b can be made continuous, and as a result, display unevenness due to abrupt brightness change in the overlapping region 29b can be effectively suppressed.

The liquid crystal display device 10 of the present disclosure described above can be effectively applied to various applications. The liquid crystal display device 10 can be used as various display devices such as a timepiece, a portable game machine, a word processor, a notebook Personal computer (note type Personal computer), a car navigation system, a video camera (cam recorder), a Personal digital assistant (Personal DIGITAL ASSISTANT, PDA), a digital camera (DIGITAL CAMERA), a mobile phone, a smart phone (smart phone), various monitors, a liquid crystal television, and an information display.

In addition, as in the photomask 100 shown in fig. 16, when the joint portion 43 is formed by connecting only two photomasks without changing the opening area of the slit 61, the luminance difference between the two adjacent light sources appears on the display screen as the luminance difference between the joint line between the exposure area of one photomask and the exposure area of the other photomask, and the joint line is easily visually recognized by the observer.

In the photomask 200 shown in fig. 17, the joint portion 43 has a halftone portion in which the opening area of the slit 61 continuously decreases in the direction from the non-repetitive region 45 toward the mask end 44. In the exposure via the photomask 200, the slit 61 having an opening area close to the exposure amount in each repetition of the exposure is disposed in the joint portion 43 (a portion surrounded by a broken line in fig. 17). Therefore, the joint 43 is locally lightened in the area where the exposure amounts are close to each other, and thus uneven banding is generated on the display screen, which tends to reduce the display quality.

Claims (16)

1. A method for manufacturing a liquid crystal display device, wherein the liquid crystal display device comprises a substrate, a photo-alignment film formed on the substrate, and a liquid crystal layer adjacent to the photo-alignment film,

The method for manufacturing a liquid crystal display device includes an exposure step of exposing an organic film on which photosensitivity is formed through a photomask while relatively moving a substrate in a predetermined moving direction with respect to a light source,

The exposure step is to expose a part of the organic film at one time and to expose at least a part of the remaining area repeatedly,

The photomask has a plurality of light-transmitting portions having the same opening area and light-shielding portions provided between the light-transmitting portions in non-repeating regions corresponding to the portions of the organic film that are subjected to one exposure, a plurality of light-transmitting portions having different opening areas and light-shielding portions provided between the light-transmitting portions in repeating regions corresponding to the portions of the organic film that are subjected to one exposure,

At least a part of the plurality of light-transmitting portions arranged in the repeating region has an opening area smaller than an opening area of the light-transmitting portion arranged in the non-repeating region,

Each light-transmitting portion arranged in the repeating region is a first light-transmitting portion having an opening area of 75% to 100% with respect to an opening area of each light-transmitting portion arranged in the non-repeating region, or is a second light-transmitting portion having an opening area of more than 0% and 25% or less.

2. The method for manufacturing a liquid crystal display device according to claim 1, wherein the photomask comprises a first photomask and a second photomask arranged adjacently along a direction intersecting the moving direction and along a substrate surface, i.e., intersecting direction, and the first photomask and the second photomask are arranged so that a part of each of them overlaps when viewed in the moving direction,

The non-repeating area is an area where the first photomask and the second photomask do not overlap when viewed in the moving direction,

The repeated area is an area where the first photomask and the second photomask overlap when viewed in the moving direction.

3. The method of manufacturing a liquid crystal display device according to claim 2, wherein the first light-transmitting portion arranged in the repetition region of one of the first photomask and the second light-transmitting portion or the light-shielding portion arranged in the repetition region of the other photomask are arranged on the same line extending in the moving direction.

4. The method for manufacturing a liquid crystal display device according to claim 2 or 3, wherein the light transmitting portions are arranged in the repeated regions so that a sum of opening areas of the light transmitting portions included in a region of a predetermined length along the intersecting direction shows an increasing tendency from a photomask end portion toward the non-repeated region.

5. The method of manufacturing a liquid crystal display device according to claim 4, wherein in the repeated region, the first light-transmitting portion is closely arranged from a photomask end toward the non-repeated region.

6. The method for manufacturing a liquid crystal display device according to claim 2 or 3, wherein the repeated region has a first section adjacent to the non-repeated region and a second section including a photomask end,

The first light-transmitting portion is arranged in the first section, the second light-transmitting portion is not arranged,

The second light transmitting portion is disposed in the second section, and the first light transmitting portion is not disposed.

7. The method for manufacturing a liquid crystal display device according to claim 6, wherein a plurality of the first light transmitting portions are arranged in the first region,

The opening area of each first light-transmitting portion disposed in the first section decreases in a direction away from the non-overlapping region.

8. The method for manufacturing a liquid crystal display device according to claim 6, wherein a plurality of the second light transmitting portions are arranged in the second region,

The opening area of each second light-transmitting portion disposed in the second section decreases in a direction toward the photomask end.

9. The method of manufacturing a liquid crystal display device according to claim 6, wherein the repeated region further has a third section provided between the first section and the second section,

In the third section, the first light transmitting portion is closely arranged from the second section toward the first section.

10. The method of manufacturing a liquid crystal display device according to claim 9, wherein an opening area of each first light-transmitting portion disposed in the first section is reduced in a direction away from the non-overlapping region,

The opening area of each second light-transmitting portion disposed in the second section decreases in a direction toward the photomask end.

11. The method for manufacturing a liquid crystal display device according to claim 2 or 3, wherein in the repeating region, the second light transmitting portion or the light shielding portion is arranged at a position symmetrical to the first light transmitting portion, and the first light transmitting portion is arranged at a position symmetrical to the second light transmitting portion, with a center line of the repeating region extending in the moving direction as an axis.

12. The method for manufacturing a liquid crystal display device according to claim 1 or 2, wherein the liquid crystal display device has two or more regions in which alignment orientations of liquid crystal molecules in the liquid crystal layer are different within one pixel.

13. The method for manufacturing a liquid crystal display device according to claim 1 or 2, wherein in the exposure step, polarized ultraviolet rays are irradiated from a direction inclined with respect to a substrate surface.

14. The method for manufacturing a liquid crystal display device according to claim 1 or 2, wherein the liquid crystal layer contains liquid crystal molecules having negative dielectric constant anisotropy therein.

15. A liquid crystal display device manufactured by the manufacturing method of a liquid crystal display device according to claim 1 or 2.

16. An exposure apparatus for manufacturing a photo-alignment film, the exposure apparatus comprising:

A light source;

a plurality of photomasks, and

A scanning unit that exposes the organic film through the plurality of photomasks while relatively moving the substrate having the photosensitive organic film with respect to the light source in a predetermined movement direction,

The plurality of photomasks are arranged in a direction intersecting the moving direction and along the substrate surface, that is, in the intersecting direction, and include a first photomask and a second photomask adjacent to the first photomask,

The first photomask and the second photomask are configured to overlap with each other at a portion thereof when viewed in the moving direction,

The first photomask and the second photomask each have a plurality of light-transmitting portions having the same opening area and light-shielding portions provided between the light-transmitting portions in non-overlapping regions where the first photomask and the second photomask do not overlap when viewed in the moving direction, and each of the first photomask and the second photomask has a plurality of light-transmitting portions having different opening areas and light-shielding portions provided between the light-transmitting portions in overlapping regions where the first photomask and the second photomask overlap when viewed in the moving direction,

At least a part of the plurality of light-transmitting portions arranged in the repeating region has an opening area smaller than an opening area of the light-transmitting portion arranged in the non-repeating region,

Each light-transmitting portion arranged in the repeating region is a first light-transmitting portion having an opening area of 75% to 100% with respect to an opening area of each light-transmitting portion arranged in the non-repeating region, or is a second light-transmitting portion having an opening area of more than 0% and 25% or less.