JP2009086571A - Liquid crystal display apparatus and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a liquid crystal display apparatus removing luminance irregularity by preventing generation of irregularity on an orientation film when forming the orientation film by using a liquid drop discharging method, and to provide the liquid crystal display apparatus. <P>SOLUTION: The liquid crystal display apparatus 100 is constituted by holding a liquid crystal layer 50 between a first substrate 10 and a second substrate 25. First and second orientation films 14, 24 including stripe-like irregularities 14a, 24a formed by a liquid drop discharging method are formed on the liquid crystal layer 50 sides of the first and second substrates 10, 25, and the irregularities 14a, 24a on the first and second orientation films 14, 24 are arranged so as not to be superposed to each other like stripes. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

It has been proposed to form an alignment film by using an inkjet method (droplet discharge method) in which ink is discharged by a droplet discharge head (see, for example, Patent Documents 1 and 2). In such an ink jet method, the entire surface of the substrate is discharged by discharging ink from the nozzles of each of the droplet discharge heads while relatively moving a droplet discharge head group including a plurality of droplet discharge heads on the substrate. An alignment film can be formed.
JP-A-7-92467 JP-A-7-92468

  In this way, in the ink ejection process using a plurality of droplet ejection heads, a configuration is adopted in which the droplet ejection heads are arranged at the front and rear with respect to the movement direction in order to bring the nozzle pitch between adjacent heads closer. However, a droplet discharge head group having a configuration in which the droplet discharge heads are arranged in the front and rear with respect to the moving direction, the ink discharged from the nozzles of the adjacent heads at the head connecting portion has a time difference on the substrate. Landing in a state where there is. For this reason, there is a difference in how ink is mixed, and uniform drying cannot be performed, resulting in uneven film thickness (unevenness). Then, luminance unevenness occurs due to the film thickness unevenness, and there is a problem that display quality is deteriorated. Therefore, a technique that can suppress a decrease in display quality due to such unevenness of the alignment film is desired.

  The present invention has been made in view of such circumstances, and provides a liquid crystal display device and a method for manufacturing the liquid crystal display device, which can suppress deterioration in display quality caused by unevenness generated in an alignment film. The purpose is that.

  In order to solve the above problems, a liquid crystal display device of the present invention is a liquid crystal display device having a liquid crystal layer sandwiched between a first substrate and a second substrate, and the liquid crystal layer side of each substrate is on the liquid crystal layer side. , Each of the substrates is provided with an alignment film including streak-like unevenness when formed by a droplet discharge method, and each of the substrates has a streak-like unevenness of the alignment film provided on each of the substrates. It arrange | positions so that it may not overlap.

  According to the liquid crystal display device of the present invention, since the unevenness when formed by the droplet discharge method does not overlap in the form of streaks, the unevenness in the form of streaks is emphasized and the display quality is deteriorated. Occurrence is prevented, and deterioration of display quality due to unevenness generated in the alignment film can be suppressed.

In the liquid crystal display device, it is preferable that the stripe-shaped unevenness of the alignment film provided on each substrate is arranged in parallel.
According to this configuration, since unevenness in each substrate does not overlap in a plan view, it is possible to suppress deterioration in display quality by dispersion of unevenness, resulting in high display quality. Can be provided.

  A method for manufacturing a liquid crystal display device according to the present invention is a method for manufacturing a liquid crystal display device having a liquid crystal layer sandwiched between a first substrate and a second substrate, wherein the first substrate and a droplet discharge head are provided. Forming a first alignment film including streaky unevenness by relatively scanning a plurality of droplet discharge head groups and discharging a functional liquid onto the first substrate; Forming a second alignment film including streak-like unevenness by relatively scanning the second substrate and the droplet discharge head group and discharging a functional liquid onto the second substrate; Bonding the first substrate and the second substrate, wherein the first alignment film and the second alignment film are formed by combining the first substrate and the second substrate. It is characterized by forming each stripe-like unevenness so that they do not overlap each other when they are bonded together. .

  According to the method for manufacturing a liquid crystal display device of the present invention, the unevenness that occurs on the first substrate and the unevenness that occurs on the second substrate do not overlap in the form of streaks when the substrates are bonded together. It is emphasized, and it is possible to prevent a problem such as a deterioration in display quality, and it is possible to suppress a reduction in display quality due to unevenness generated in the alignment film.

In the method of manufacturing the liquid crystal display device, the first substrate and the second substrate are arranged so that the stripe-shaped unevenness of the first alignment film and the second alignment film are parallel to each other. It is preferable to bond them together.
According to this configuration, since unevenness in the first substrate and the second substrate does not overlap in a plan view, deterioration in display quality can be suppressed by dispersion of unevenness, and more display. High quality can be provided.

In the method of manufacturing the liquid crystal display device, in the step of forming the second alignment film, the first substrate and the droplet discharge head group in the step of forming the first alignment film may be relative to each other. It is preferable to scan in a state where the position is shifted by one pitch or more of the nozzles of the droplet discharge head in a direction crossing the scanning direction.
According to this configuration, when the second alignment film is formed, the relative position of the droplet discharge head group with respect to the substrate is shifted by one pitch or more of the nozzles, so that the first alignment film does not overlap with the unevenness of the first alignment film. 2 alignment films can be easily formed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the technical scope of the present invention is not limited to the following embodiments. In the drawings used for the following description, the scale of each member is appropriately changed in order to make each member a recognizable size.

First, the structure of the liquid crystal display device manufactured based on one Embodiment of the manufacturing method of the liquid crystal display device of this invention is demonstrated.
FIG. 1A is a partial plan configuration diagram mainly showing an alignment film in the liquid crystal display device, and FIG. 1B is a partial cross-sectional configuration diagram of the liquid crystal display device 100 corresponding to FIG. . FIG. 2 is a diagram illustrating an overall configuration of the liquid crystal display device 100, and FIG. 3 is a diagram illustrating an equivalent circuit of the liquid crystal display device 100.

  Referring to the cross-sectional structure shown in FIG. 1B, the liquid crystal display device 100 includes a TFT array substrate (first substrate) 10 and a counter substrate (second substrate) 25 disposed to face the TFT array substrate (first substrate) 10. A liquid crystal layer 50 is sandwiched between the substrates 10 and 25. The liquid crystal layer 50 is formed in a substantially constant layer thickness within the substrate surface. A backlight 60 having a light source, a reflector, a light guide plate, and the like is disposed on the back side of the liquid crystal panel corresponding to the outer surface side of the TFT array substrate 10.

  An alignment film (first alignment film) 14 and an alignment film (second alignment film) 24 are provided on the liquid crystal layer 50 side of the substrates 10 and 25. As will be described later in detail, the alignment films 14 and 24 are formed by a droplet discharge method (inkjet method) and are made of polyimide. Further, in the present embodiment, the alignment films 14 and 24 are ejected onto the substrate while the droplet discharge head group including a plurality of droplet discharge heads is moved onto the substrate and ink containing the alignment film forming material is discharged onto the substrate. Is forming.

  When such a droplet discharge process is used, streaky irregularities 14 a and 24 a are formed in the alignment films 14 and 24. That is, the alignment films 14 and 24 according to the present embodiment include stripe-shaped unevenness 14a and 24a.

  FIG. 1A shows the liquid crystal display device 100 as viewed from the counter substrate 25 side, and as shown in the figure, these unevennesses 14a and 24a do not overlap in a streak shape. Specifically, in the present embodiment, the alignment films 14 and 24 are arranged so that the unevenness 14a and 24a are parallel to each other.

  By the way, when the unevenness 14a of the alignment film 14 on the TFT array substrate 10 side and the unevenness 24a of the alignment film 24 on the counter substrate 25 side overlap in a plan view, the unevenness is emphasized, so that the display quality in the liquid crystal display device 100 is improved. The problem that it falls is generated.

  On the other hand, in the liquid crystal display device 100 according to the present embodiment, since the unevennesses 14a and 24a of the alignment films 14 and 24 are parallel to each other as described above, the unevenness 14a. It is prevented that 24a overlaps (intersection point). Therefore, the unevenness is dispersed over the entire display area, so that the deterioration of display quality due to the unevenness 14a, 24a is suppressed.

  The TFT array substrate 10 has a substrate body 10A made of a translucent material such as quartz or glass as a base, and a light-transmitting material such as ITO (indium tin oxide) is formed on the inner surface side (liquid crystal layer 50 side) of the substrate body 10A. A pixel electrode 9 made of a conductive conductive material is formed in each pixel region, and the alignment film 14 is formed so as to cover the pixel electrode 9.

  Note that a TFT as a switching element for driving the pixel electrode 9 is formed on the TFT array substrate 10, but the illustration thereof is omitted in this figure. In addition, on the outer surface side of the substrate body 10A, a phase difference plate 16 and a polarizing plate 17 are sequentially stacked from the substrate body 10A side.

  The counter substrate 25 includes a substrate main body 25A made of a translucent material such as quartz or glass as a base, and the color filter layer 22 is formed on the inner surface side of the substrate main body 25A in the region partitioned by the light shielding portion 45 as described above. Is formed.

  The light shielding portion 45 is made of, for example, a conductive material containing carbon black. The color filter layer 22 includes a light shielding portion 45 extending in a substantially lattice shape in a plan view, and colored layers 22R, 22G, each of a plurality of substantially rectangular shapes in a plan view formed in a gap between the light shielding portions 45. 22B. Regions partitioned by the light shielding portions 45 constitute pixel regions in the liquid crystal display device 100. Further, the light shielding portion 45 has a function of preventing color mixing of light from the adjacent colored layers 22R, 22G, and 22B.

  A common electrode 23 made of a light-transmitting conductive material such as ITO (indium tin oxide) is formed so as to cover the light shielding portion 45 and the color filter layer 22. Further, the alignment film 24 is formed so as to cover the common electrode 23.

On the outer surface side of the substrate body 25A, a phase difference plate 26 and a polarizing plate 27 are sequentially stacked from the substrate body 25A side.
The polarizing plates 17 and 27 have a function of transmitting only linearly polarized light that vibrates in a specific direction. The retardation plates 16 and 26 are provided as necessary. For example, a λ / 4 retardation plate having a phase difference of approximately ¼ wavelength with respect to the wavelength of visible light, or a retardation plate having a viewing angle compensation function. Is used.

  Next, a specific configuration example of the liquid crystal display device according to the present invention will be described with reference to FIGS. 2 and 3, the same reference numerals are given to the same components as those of the liquid crystal display device 100 shown in FIG. 1, and the description thereof will be omitted.

  As shown in FIG. 2, the liquid crystal display device 100 includes a region in which the TFT array substrate 10 and the counter substrate 25 are bonded together via a sealing material 52 having a substantially rectangular frame shape in plan view and partitioned by the sealing material 52. The liquid crystal layer 50 is enclosed therein. A peripheral parting portion 53 made of a light shielding material is formed in a rectangular frame shape in a region inside the sealing material 52. In the peripheral circuit area outside the sealing material 52, the data line driving circuit 201 and the external circuit mounting terminal 202 are disposed along one side of the TFT array substrate 10, and scanning is performed along two sides adjacent to the one side. Line drive circuits 104 and 104 are provided. On the remaining side of the TFT array substrate 10, a plurality of wirings 105 for connecting the scanning line driving circuits 104, 104 provided on both sides of the display area are formed. In addition, an inter-substrate conductive material 106 for providing electrical continuity between the TFT array substrate 10 and the counter substrate 25 is disposed at a corner portion of the counter substrate 25.

  FIG. 3 is a transmission circuit diagram of the liquid crystal display device 100 of the present embodiment. In the liquid crystal display device according to the present embodiment, the pixel electrode 9 and the TFT 30 that is a switching element for controlling the pixel electrode 9 are respectively formed on the plurality of dots arranged in a matrix that forms the image display region. The data line 6 a to which the image signal is supplied is electrically connected to the source of the TFT 30. Image signals S1, S2,..., Sn to be written to the data line 6a are supplied line-sequentially in this order, or are supplied for each group to a plurality of adjacent data lines 6a. Further, the scanning line 3a is electrically connected to the gate of the TFT 30, and the scanning signals G1, G2,..., Gm are applied to the plurality of scanning lines 3a in a pulse-sequential manner at a predetermined timing. Further, the pixel electrode 9 is electrically connected to the drain of the TFT 30, and by turning on the TFT 30 as a switching element for a certain period, the image signals S1, S2,. Write at the timing.

  Image signals S1, S2,..., Sn written at a predetermined level on the liquid crystal via the pixel electrode 9 are held with the common electrode 23 for a certain period. The liquid crystal modulates light by changing the orientation and order of the molecular assembly according to the applied voltage level, thereby enabling gradation display. Here, in order to prevent the held image signal from leaking, a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9 and the common electrode 23. Reference numeral 3b denotes a capacity line.

  According to the liquid crystal display device 100 according to the present embodiment, when the alignment films 14 and 24 are formed by the droplet discharge method, the unevenness generated in the alignment films 14 and 24 does not overlap. It is possible to prevent a problem such as a deterioration in display quality and to suppress a reduction in display quality due to unevenness generated in the alignment films 14 and 24.

(Manufacturing method of liquid crystal display device)
Next, as an embodiment of a method for manufacturing a liquid crystal display device according to the present invention, a process for manufacturing the liquid crystal display device 100 will be described as an example. The manufacturing method according to the present invention is characterized in that the alignment films 14 and 24 are formed on the inner surface side (the liquid crystal layer 50 side) of the TFT array substrate 10 and the counter substrate 25 by using a droplet discharge method. In the following description, the formation process of the alignment films 14 and 24 using the droplet discharge method will be described in detail.

  First, the configuration of the droplet discharge device IJ used in the inkjet (droplet discharge) process for forming the alignment films 14 and 24 will be described. FIG. 4 is a diagram showing a schematic configuration of the droplet discharge device IJ.

  As shown in FIG. 4, the droplet discharge device IJ is a droplet discharge device (inkjet device) that can supply ink (liquid material) in a predetermined pattern onto a substrate Z, and has a base 112 installed horizontally. A stage 138 that is provided on the base 112 and supports the substrate Z, a first moving device 130 that is interposed between the base 112 and the stage 138 and supports the stage 138 so as to be movable, and is supported by the stage 138. A droplet discharge head group 20 capable of quantitatively discharging (dropping) ink droplets containing a predetermined material with respect to the substrate Z, and a second moving device that movably supports the droplet discharge head group 20 140.

  Here, the configuration of the droplet discharge head group 20 will be described in detail. FIG. 5 is a schematic configuration diagram of the droplet discharge head group 20. As shown in FIG. 5, the droplet discharge head group 20 includes a plurality of droplet discharge heads 20 a on which nozzles 19 for discharging ink are formed, and the width thereof is a base material for discharging ink. The width is wider than Z (corresponding to the substrates 10 and 25 in this embodiment). Thereby, the droplet discharge head group 20 can form a desired thin film on the entire surface of the substrate Z by scanning the substrate Z only once (in this embodiment, the alignment films 14 and 24 are formed). Forming).

Each of these droplet discharge heads 20a is disposed so as to be shifted back and forth with respect to the relative movement direction with respect to the substrate Z (arranged in a staggered manner in this embodiment).
By adopting such an arrangement, it is possible to reduce the pitch between the nozzles 19 of the adjacent heads 20a in the region surrounded by the wavy line in FIG.
The droplet discharge head group 20 includes a first head row 29 including two droplet discharge heads 20a and a second head row 28 including three droplet discharge heads 20a. Therefore, ink is ejected over the entire lateral width of the substrate Z by ejecting ink from the head 20a of the second head row 28 so as to interpolate a region where ink is not ejected from the head 20a of the first head row 29. It becomes possible.

  By the way, each droplet discharge head 20a adopts a piezo method, and the droplet discharge by this piezo method has an advantage that it does not affect the composition of the ink because heat is not applied to the ink. . Specifically, as shown in FIG. 6, the droplet discharge head 20 a is provided with a piezo element 122 adjacent to a liquid chamber 121 that stores ink (functional liquid) I. Ink is supplied to the liquid chamber 121 via an ink supply system 123 including a tank for storing ink.

  The piezo element 122 is connected to the drive circuit 124, and when a voltage is applied to the piezo element 122 via the drive circuit 124, the piezo element 122 is deformed and presses the liquid chamber 121, so that the ink I is ejected from the nozzle. 19 is discharged. In this case, the amount of distortion of the piezo element 122 is controlled by changing the voltage value to be applied. Further, the strain rate of the piezo element 122 is controlled by changing the frequency of the applied voltage.

Examples of the ink ejection technique include a charge control method, a pressure vibration method, an electromechanical conversion method, an electrothermal conversion method, and an electrostatic suction method. Among these, the charge control method applies charge to ink with a charging electrode, and controls the flight direction of the ink with a deflection electrode to discharge the ink from the nozzle. On the other hand, the pressure vibration method applies an ultra-high pressure of about 30 kg / cm 2 to the ink and ejects the ink from the tip of the nozzle. When no control voltage is applied, the ink moves straight from the nozzle. When ejected and a control voltage is applied, electrostatic repulsion occurs between the inks, and the ink scatters and is not ejected from the nozzles.
On the other hand, as described above, the electromechanical conversion method uses the property that a piezo element (piezoelectric element) deforms in response to a pulsed electric signal, and the piezo element deforms into a space where ink is stored. Pressure is applied through a flexible material, ink is pushed out from this space, and ink is ejected from the nozzles.
On the other hand, in the electrothermal conversion method, a heater provided in a space in which ink is stored causes the ink to rapidly vaporize to generate bubbles, and the material in the space is ejected by the pressure of the bubbles. In the electrostatic suction method, a minute pressure is applied to a space in which ink is stored to form an ink meniscus in the nozzle, and an electrostatic attractive force is applied in this state before the ink is drawn out.
In addition, there are other techniques such as a system that uses a change in the viscosity of a fluid due to an electric field and a system that uses a discharge spark. The ink jet method has an advantage that the use of ink is less wasteful and a desired amount of ink can be accurately disposed at a desired position. The amount of one drop of ink (fluid) ejected by the ink jet method is, for example, 1 to 300 nanograms.

A control device 61 that controls the operation of the droplet discharge device IJ including the discharge operation of the droplet discharge head group 20 and the movement operations of the first moving device 130 and the second moving device 140 is provided.
A direction along the front-rear direction of the base 112 is a Y direction, and a direction along the left-right direction of the base 112 is an X direction. A direction perpendicular to the X direction and the Y direction is a Z direction, and a rotation method around the Z axis is a θz direction.

The first moving device 130 includes a guide rail 132 installed on the base 112, a slider 134 supported so as to be movable along the guide rail 132, and a drive unit (non-linear) such as a linear motor that moves the slider 134. (Illustrated).
Then, by driving the first moving device 130 according to an instruction from the control device 61, the slider 134 can be moved in the Y direction along the guide rail 132, and the base material Z can be positioned.

  A stage 138 is supported on the slider 134 via a Z-axis rotation (θz) motor 136. The motor 136 is a direct drive motor, for example, and the stage 136 can be slightly rotated in the θz direction with respect to the slider 134 by driving the motor 136. That is, the first moving device 130 supports the stage 138 so as to be movable in the Y direction and the θz direction. The stage 138 holds the substrate Z, and the substrate Z can be sucked and held on the stage 138 by a suction holding device (not shown) provided on the upper surface.

The second moving device 140 includes two pillars 74 erected substantially at the center of the base 112, a column 76 fixed along the X direction by the pillars 74, a guide rail 142 supported by the column 76, The slider 144 is supported so as to be movable in the X direction along the guide rail 142, and a drive unit (not shown) such as a linear motor that moves the slider 144.
Then, by driving the second moving device 140 according to an instruction from the control device 61, the slider 144 can be moved in the X direction along the guide rail 142, and the droplet discharge head group 20 can be positioned. The feed direction that is the moving direction of the slider 144 by the second moving device 140 is a direction orthogonal to the scanning direction that is the moving direction of the slider 134 by the first moving device 130.

  The slider 144 supports the droplet discharge head group 20 via motors 146 and 48. Then, by operating the motor 146, the droplet discharge head group 20 can be slightly moved up and down along the Z direction for positioning. Further, by operating the motor 148, the droplet discharge head group 20 can be positioned by slightly rotating around the Z axis (θz direction).

  That is, the second moving device 140 supports the droplet discharge head group 20 so as to be movable in the X direction, and supports the droplet discharge head group 20 so as to be finely movable in the Z direction and the θz direction. Thereby, the droplet discharge surface of the droplet discharge head group 20 can be accurately aligned with respect to the substrate Z placed on the stage 138. In addition, by making the droplet ejection surface of the droplet ejection head group 20 and the upper surface of the base material Z close to 1 mm or less, the flight bending of the ejected droplets can be suppressed and the droplet placement accuracy can be improved. .

Next, a process for manufacturing an alignment film using the droplet discharge device IJ will be described.
FIG. 7A is a diagram showing a process of forming the alignment film 14 on the TFT array substrate 10, and FIG. 7B is a diagram showing a process of forming the alignment film 24 on the counter substrate 25. In the figure, the configurations of both substrates 10 and 25 are shown in a simplified state.

  In the step shown in FIG. 7A, first, a substrate body 10A on which a TFT 30, a pixel electrode 9 and the like are formed by a conventionally known method is placed on a stage 138 of a droplet discharge device IJ as a base material Z. Similarly, in the process shown in FIG. 7B, the substrate body 25A on which the color filter layer 22 and the common electrode 23 are formed by a conventionally known method is used as the base material Z on the stage 138 of the droplet discharge device IJ. Deploy.

Subsequently, the alignment films 14 and 24 can be formed on the substrate bodies 10A and 25A by discharging the ink I containing the alignment film forming material from the droplet discharge head group 20 and performing a drying process.
.

  The solvent of the ink I is not particularly limited as long as it does not cause aggregation. For example, water, alcohols such as methanol, ethanol, propanol, and butanol, n-heptane, n-octane, decane, Hydrocarbon compounds such as dodecane, tetradecane, toluene, xylene, cymene, durene, indene, dipentene, tetrahydronaphthalene, decahydronaphthalene, cyclohexylbenzene, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, Diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, - ether compounds such as dioxane, propylene carbonate, .gamma.-butyrolactone, N- methyl-2-pyrrolidone, dimethylformamide, dimethyl sulfoxide, and cyclohexanone.

  The surface tension of the ink I is preferably in the range of 0.02 N / m to 0.07 N / m. When the ink is ejected by the ink jet method, if the surface tension is less than 0.02 N / m, the wettability of the ink to the nozzle increases, and thus flight bending easily occurs. If the surface tension exceeds 0.07 N / m, the nozzle Since the shape of the meniscus at the tip is not stable, it becomes difficult to control the discharge amount and the discharge timing. In order to adjust the surface tension, the solvent may contain a surface tension regulator such as a fluorine-based, silicone-based, or nonionic-based material in a range that does not significantly reduce the contact angle with the substrate and does not affect the alignment of the liquid crystal. Add a trace amount. The nonionic surface tension modifier improves the wettability of the ink I to the substrate, improves the leveling property of the film, and helps prevent the occurrence of fine irregularities in the film. The surface tension adjusting agent may contain an organic compound such as alcohol, ether, ester, and ketone, if necessary.

  The viscosity of the ink I is preferably 1 mPa · s to 50 mPa · s. When the ink I is ejected as droplets using the inkjet method, if the viscosity is less than 1 mPa · s, the nozzle periphery is easily contaminated by the outflow of the ink I, and if the viscosity is greater than 50 mPa · s, The frequency of clogging of the nozzles increases, and it becomes difficult to smoothly discharge droplets.

  The drying process of the ink I discharged onto the substrate can be performed by a heating process using, for example, a hot plate or an electric furnace. This drying process can also be performed by lamp annealing. The light source used for lamp annealing is not particularly limited, but excimer lasers such as infrared lamps, xenon lamps, YAG lasers, argon lasers, carbon dioxide lasers, XeF, XeCl, XeBr, KrF, KrCl, ArF, ArCl, etc. It can be used as a light source. In addition, although such heat processing or light processing is normally performed in air | atmosphere, it can also be performed in inert gas atmosphere, such as nitrogen, argon, and helium, as needed.

By the way, streaky irregularities 14a and 24a are generated in the alignment films 14 and 24, respectively.
Hereinafter, the reason why the unevenness 14a, 24a occurs in the alignment films 14, 24 will be described.
FIG. 8 is a diagram showing a state in which ink is ejected from the droplet ejection head group 20 onto the substrate Z. In the droplet discharge process, first, the ink I is discharged from the droplet discharge head 20a of the first head row 29 in the droplet discharge head group 20 onto the substrate Z as shown in FIG. As a result, ink droplets IA are formed at positions corresponding to the respective droplet ejection heads 20a of the first head row 29. As the droplet discharge head group 20 moves, the ink I is discharged from the droplet discharge head 20a of the second head row 28 as shown in FIG. As a result, ink droplets IB are formed at positions corresponding to the respective droplet discharge heads 20a in the second head row 28.

  Therefore, the ink droplets IA and IB ejected from the droplet ejection head 20a of the adjacent first head row 29 and the droplet ejection head 20a of the second head row 28 are respectively on the substrate Z in a state where a time difference has occurred. To land. For this reason, a difference occurs in the mixing method of the ink droplets IA and IB, so that uniform drying is not performed in the drying process, resulting in film thickness unevenness. That is, when the alignment films 14 and 24 are formed on the substrates 10 and 25 using the droplet discharge head group 20, the positions corresponding to the boundaries between the first head row 29 and the second head row 28 are shown in FIG. ) And (b), unevenness 14a and 24a are generated.

  In this embodiment, when the alignment film 24 is formed on the counter substrate 25 shown in FIG. 7B, the relative position X of the droplet discharge head group 20 with respect to the substrate is shifted by 1 nozzle P or more in the droplet discharge head 20a. Going in state. Accordingly, as shown in FIG. 7B, the unevenness 24a generated in the alignment film 24 can be easily and reliably shifted from the unevenness 14a generated in the alignment film 14 formed in FIG. 7A.

  At this time, the droplet discharge head group 20 moves in parallel to the substrates 10A and 25A. Therefore, the irregularities 14a and 24a are formed in stripes along the moving direction of the droplet discharge head group 20, respectively.

Subsequently, the liquid crystal layer 50 is sandwiched between the substrates 10 and 25 formed as described above, and the substrates are bonded to each other via a sealing material 52.
At this time, both the substrates 10 and 25 are bonded so that the unevenness 14a and 24a are parallel to each other. As a result, the unevenness 14a and 24a in the TFT array substrate 10 and the counter substrate 25 do not overlap in a plan view, and a high-quality liquid crystal display device in which deterioration in display quality is suppressed by dispersing the unevenness. 100 can be manufactured.

(Modification)
In the above-described embodiment, the alignment film is formed on the substrate by moving the droplet discharge head group 20 including the plurality of droplet discharge heads 20a. However, the discharge area of the droplet discharge head is smaller than the width of the substrate on which the alignment film is formed, that is, the alignment film is formed on the substrate using one droplet discharge head 20a as shown in FIG. In this case, the droplet discharge head 20a is made to reach one end side of the substrate while discharging the ink along the −Y-axis direction in the figure, and then the droplet discharge head 20a is returned to the other end side of the substrate in the drawing. Move in the + X-axis direction. Then, ink is ejected onto the substrate again. In this way, the alignment film can be formed on the entire surface of the substrate by ejecting ink while making the droplet ejection head 20a line feed. As shown in FIG. 9, the unevenness as described above is formed at the portion where the droplet discharge head is broken. Even in such a case, the present invention is effective.

  In this case, when the alignment film of the TFT array substrate 10 is formed and when the alignment film of the counter substrate 25 is formed, the discharge start position (relative position) of the droplet discharge head 20a with respect to the substrate is made different, whereby the alignment film 14, What is necessary is just to make the position of the nonuniformity formed in 24 differ. Thereby, the substrates 10 and 25 can be bonded so that the unevenness does not overlap at least in the form of stripes, and a liquid crystal display device with high display quality in which the deterioration of display quality is suppressed by the unevenness being dispersed is manufactured. Can do.

(Electronics)
Next, electronic devices to which the liquid crystal display device of the present invention is applied will be described.
FIG. 10 is a perspective view of a mobile phone 1000 shown as an example of an electronic apparatus to which the present invention is applied.
A cellular phone 1000 illustrated in FIG. 10 includes a display portion 1001, a plurality of operation buttons 1002, a mouthpiece 1003, and a mouthpiece 1004. The display portion 1001 includes the liquid crystal display device 100 described above. ing. Therefore, in the mobile phone 1000 including such a liquid crystal display device 100, high-quality color display without uneven brightness can be performed on the display portion 1001.

  Note that the electronic apparatus to which the present invention is applied is not limited to such a cellular phone 1000. For example, an electronic book, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type or a monitor direct view type video tape recorder, a car Examples include a navigation device, a pager, an electronic notebook, a calculator, a word processor, a workstation, a video phone, a POS terminal, and a device equipped with a touch panel. That is, the present invention can be widely applied to electronic devices including image display means, and any electronic device can perform high-quality color display with excellent color characteristics.

  The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention, and the specific materials and configurations described in the embodiment. These are merely examples, and can be changed as appropriate.

(A) is a partial plane block diagram which shows an orientation film, (b) is a cross-sectional block diagram. It is a figure which shows the whole structure of a liquid crystal display device. It is a figure which shows the equivalent circuit of a liquid crystal display device. It is a figure which shows schematic structure of a droplet discharge apparatus. It is a figure which shows schematic structure of a droplet discharge head group. It is explanatory drawing of ink discharge operation | movement. (A), (b) is a figure for demonstrating the formation process of alignment film. (A), (b) is a figure for demonstrating the nonuniformity which arises in alignment film. It is a figure which shows the modification based on this invention. It is a block diagram of the mobile telephone which is one Embodiment of an electronic device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... TFT array substrate (first substrate), 14 ... Alignment film (first alignment film), 20 ... Droplet discharge head group, 20a ... Droplet discharge head, 24 ... Alignment film (second alignment film) 24a ... unevenness, 25 ... counter substrate (second substrate), 25a ... unevenness, 50 ... liquid crystal layer, 100 ... liquid crystal display device, I ... ink (functional liquid)

Claims (5)

A liquid crystal display device having a liquid crystal layer sandwiched between a first substrate and a second substrate,
On the liquid crystal layer side of each substrate, an alignment film including streaky unevenness when formed by a droplet discharge method is provided,
The liquid crystal display device, wherein each of the substrates is arranged so that the stripe-shaped unevenness of the alignment film provided on the substrates does not overlap with each other.   The liquid crystal display device according to claim 1, wherein the stripe-shaped unevenness of the alignment film provided on each substrate is arranged in parallel. A method of manufacturing a liquid crystal display device having a liquid crystal layer sandwiched between a first substrate and a second substrate,
The first substrate and a droplet discharge head group in which a plurality of droplet discharge heads are arranged are relatively scanned, and functional liquid is discharged onto the first substrate, thereby causing streak-like unevenness. Forming a first alignment film;
Forming a second alignment film including streaky irregularities by relatively scanning the second substrate and the droplet discharge head group and discharging a functional liquid onto the second substrate; When,
Bonding the first substrate and the second substrate, and
The first alignment film and the second alignment film are formed such that when the first substrate and the second substrate are bonded to each other, the respective streaky irregularities do not overlap each other in a streak shape. A method for manufacturing a liquid crystal display device.   The first substrate and the second substrate are bonded to each other so that the streaky unevenness of the first alignment film and the second alignment film are parallel to each other. Liquid crystal display device manufacturing method.   In the step of forming the second alignment film, the droplet in the direction intersecting the scanning direction with respect to the relative position of the first substrate and the droplet discharge head group in the step of forming the first alignment film. 5. The method of manufacturing a liquid crystal display device according to claim 3, wherein scanning is performed in a state where the nozzles of the ejection head are shifted by one pitch or more.

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