JP2008170844A - Manufacturing method of liquid crystal display device and droplet discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of liquid crystal display device and a droplet discharge device reducing display irregularity due to film thickness level difference of an alignment film. <P>SOLUTION: By scanning a counter substrate 15 in a Y direction, a first liquid film FL1 along a direction intersecting a rib 30 is formed. Further, by moving a carriage to a next line in an X direction and scanning the counter substrate 15 in the anti-Y direction, a second liquid film FL2 along the direction intersecting the rib 30 is formed. Further, a protrusion part FLO where the first liquid film FL1 and the second liquid film FL2 overlap each other is formed along the direction intersecting the rib 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

In the liquid crystal display device, in order to define the alignment state of liquid crystal molecules, a protrusion, an alignment film, and the like are provided on the inner surface of a transparent substrate that encloses the liquid crystal molecules (for example, Patent Document 1). As a method for producing the alignment film, a flexographic printing method is used in which the flexographic plate coated with the alignment film material is pressed against a transparent substrate, and the alignment film material of the flexographic plate is transferred to the transparent substrate. In the flexographic printing method, an alignment film having a shape corresponding to the flexographic plate is formed on the transparent substrate. Therefore, as the transparent substrate increases in size, it takes a lot of time to replace the flexographic plate. Further, since the flexographic printing method applies the alignment film material to the entire flexographic plate, the use efficiency of the alignment film material becomes low.

Therefore, in the method of manufacturing the alignment film, proposals have conventionally been made to solve the above production problems. Patent Document 2 proposes a so-called inkjet method in which alignment film forming liquid is discharged as droplets onto a substrate, and droplets that have landed on the substrate are dried to form an alignment film.

In the inkjet method, since the alignment film forming liquid is ejected from the nozzle, the solvent component of the alignment film forming liquid used in the flexographic printing method must be increased, and the viscosity of the alignment film forming liquid must be 10 mPa · s or less. Such a low-viscosity liquid material causes a large difference in the vapor pressure of the solvent between the central portion and the peripheral portion of the discharge region when the droplets are dried. That is, the peripheral portion of the discharge region with a low vapor pressure has a higher concentration of the alignment film material and a higher surface tension of the alignment film material than the central portion of the discharge region. As a result, the alignment film forming liquid discharged to the central part flows to the peripheral part, and the film thickness of the central part becomes thinner than the film thickness of the peripheral part.

The film thickness difference becomes more prominent when the ejection head is scanned for line feed. That is,
When the width of the discharge area is larger than the width of the discharge head, the discharge head is scanned for line feed several times over the discharge area. The droplets ejected by the preceding scan begin to dry faster than the droplets ejected by the subsequent scan, and the viscosity is lowered. As a result, every time the liquid droplets ejected by the subsequent scan flow toward the liquid droplets ejected by the preceding scan,
A step in the film thickness (return line streak) occurs at the boundary between the preceding scan and the subsequent scan.

In Patent Document 2, in order to solve the above problem, a plurality of nozzle rows are provided in a discharge head for discharging droplets, and alignment film forming liquids having different concentrations are discharged for each nozzle row. That is, a high concentration alignment film forming liquid is discharged to the central portion of the discharge region or the scanning region, and a low concentration alignment film forming liquid is discharged to the peripheral portion of the discharge region or the scanning region. Thereby, the concentration distribution accompanying the flow of the alignment film forming liquid can be compensated, and the film thickness uniformity of the alignment film can be improved.
JP 2006-64900 A JP 2006-35062 A

However, since Patent Document 2 requires alignment film forming liquids having different concentrations, adjustment of the alignment film forming liquid and concentration management of the alignment film forming liquid become complicated. Further, every time the size or shape of the discharge region is changed, various discharge conditions such as the concentration of each alignment film forming liquid, the discharge position, and the discharge amount must be optimized. As a result, the inkjet method is difficult to obtain versatility.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for manufacturing a liquid crystal display device and a droplet discharge device in which display unevenness due to a film thickness difference of an alignment film is reduced. That is.

The method for producing a liquid crystal display device of the present invention is a method for producing a liquid crystal display device having an alignment film on a transparent substrate, the discharge head having a plurality of nozzles arranged in one direction, and the transparent substrate. The plurality of droplets that are relatively moved along the other direction intersecting the one direction, ejecting a plurality of droplets containing an alignment film material from the plurality of nozzles toward the transparent substrate, and landed on the transparent substrate And a step of forming a step portion extending in a direction crossing the other direction on the transparent substrate.

According to the manufacturing method of the liquid crystal display device of the present invention, the alignment division of the liquid crystal molecules due to the film thickness step along the relative movement direction can be divided by the step portion. Therefore, display unevenness due to the film thickness difference of the alignment film can be reduced.

In this method of manufacturing a liquid crystal display device, after the step portion is formed, the plurality of droplets containing the alignment film material are ejected toward the transparent substrate, and the plurality of droplets landed on the transparent substrate are discharged. You may dry and perform an orientation process.

According to this method of manufacturing a liquid crystal display device, since the droplets that have landed near the stepped portion are guided to the stepped portion and diffused, the film thickness step along the relative movement direction can be dispersed in the direction of the stepped portion. . Moreover, the alignment division of the liquid crystal molecules due to the film thickness step along the relative movement direction can be divided by the step portion. Accordingly, display unevenness of the liquid crystal display device can be further reduced.

In this method of manufacturing a liquid crystal display device, before forming the stepped portion, the plurality of droplets containing the alignment film material are ejected toward the transparent substrate and landed on the transparent substrate. May be dried for orientation treatment.

According to this method for manufacturing a liquid crystal display device, an alignment process such as a rubbing process can be performed on a flatter alignment film as much as there is no step portion on the base of the alignment film. Therefore, the alignment treatment of the alignment film can be performed more uniformly, and the display unevenness of the liquid crystal display device can be reduced more reliably.

In this method of manufacturing a liquid crystal display device, the stepped portion may be a convex portion that regulates the alignment direction of liquid crystal molecules.
The droplet discharge device of the present invention includes a plurality of nozzles arranged in one direction, a discharge head that discharges droplets containing alignment film material from each of the plurality of nozzles, and a stepped portion that extends in the other direction. A relative movement means for relatively moving the transparent substrate having the discharge head in a direction intersecting the other direction, and driving the relative movement means to relatively move the transparent substrate and the discharge head;
And a controller that drives the discharge head to discharge the plurality of droplets from each of the plurality of nozzles toward the transparent substrate.

According to the droplet discharge device of the present invention, the droplets that have landed in the vicinity of the stepped portion are guided to the stepped portion and diffused, so that the film thickness step along the relative movement direction can be dispersed in the direction of the stepped portion. . Moreover, the alignment division of the liquid crystal molecules due to the film thickness step along the relative movement direction can be divided by the step portion. Therefore, display unevenness caused by the film thickness difference of the alignment film can be reduced.

In this droplet discharge device, the relative movement unit may be a substrate stage on which the transparent substrate is placed and the transparent substrate is moved in a direction orthogonal to the one direction.
According to this droplet discharge device, scanning by the substrate stage reduces display unevenness caused by the film thickness step of the alignment film.

In this droplet discharge device, the stepped portion may be a convex portion that regulates the alignment direction of liquid crystal molecules.

(First embodiment)
Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. First, the liquid crystal display device 10 will be described. FIG. 1 is a perspective view showing a liquid crystal display device 10.

In FIG. 1, a liquid crystal display device 10 is, for example, an MVA (Multi domain Vertical Alignm).
ent) type liquid crystal display device having a backlight 11 and a liquid crystal panel 12. The backlight 11 irradiates the entire surface of the liquid crystal panel 12 with light emitted from the light source 13 such as an LED. The liquid crystal panel 12 includes transparent substrates (element substrate 14 and counter substrate 15) that face each other. The element substrate 14 and the counter substrate 15 are bonded together by a rectangular frame-shaped sealing material 16, and the liquid crystal LC is sealed in the gap. The liquid crystal LC is, for example, VA (Vertical Alignment)
This is a liquid crystal of the type, which makes it possible to use an alignment division technique (multi-domain).

An optical substrate 17 such as a polarizing plate or a retardation plate is bonded to the lower surface of the element substrate 14. The optical substrate 17 has a transmission axis in a predetermined direction, and allows light from the backlight 11 to be transmitted toward the liquid crystal LC.

On the upper surface of the element substrate 14 (hereinafter simply referred to as an element formation surface 14a), a plurality of scanning lines Lx extending in one direction are arranged. Each scanning line Lx is connected to a scanning line driving circuit 19 disposed on one side of the element substrate 14. Each scanning line Lx includes a scanning line driving circuit 1
9 is input at a predetermined timing.

On the element formation surface 14a, a plurality of data lines Ly extending in a direction orthogonal to the scanning lines Lx are arranged. Each data line Ly is connected to a data line driving circuit 18 disposed on the other side of the element substrate 14. A data signal based on display data from the data line driving circuit 18 is input to each data line Ly at a predetermined timing.

Here, the direction in which the scanning line Lx extends is referred to as the X direction, and the direction in which the data line Ly extends is referred to as the Y direction.
In FIG. 2, a plurality of pixels 20 partitioned by scanning lines Lx and data lines Ly are formed on the element formation surface 14 a of the element substrate 14. Each pixel 20 has a TF.
A switching element 21 made of T and a light-transmissive pixel electrode 22 are provided.

Each pixel electrode 22 has a plurality of slits 22S. Each slit 22S is
Each is a concave groove formed in the corresponding pixel electrode 22. Each slit 22S is formed in a ninety-nine fold shape that intermittently straddles each pixel electrode 22 in the Y direction, and has an inclination angle θ with respect to the Y direction.
It is formed along a direction inclined by (90> θ ≧ 0).

On the upper side of each pixel electrode 22, an alignment film 23 subjected to an alignment process such as a rubbing process is laminated. The alignment film 23 is a thin film made of an alignment polymer such as alignment polyimide, and regulates the alignment state of the liquid crystal LC in the vicinity of the corresponding pixel electrode 22. For the alignment film 23, an alignment film ink in which an alignment film material (for example, an alignment polymer) is dispersed is discharged as droplets on the entire upper side of each pixel 20, and a liquid film composed of a plurality of droplets is dried. It is formed.

In FIG. 1, a polarizing plate 24 is disposed on the upper surface of the counter substrate 15. The polarizing plate 24 has a transmission axis in a predetermined direction and allows light from the liquid crystal LC to pass therethrough.
In FIG. 3, on the lower surface of the counter substrate 15 (surface on the element substrate 14 side: electrode forming surface 15a)
A black matrix 25 is formed. The black matrix 25 is the element substrate 1
4 is a light shielding member that shields light from the four sides, and is formed in a lattice shape facing the scanning lines Lx and the data lines Ly. Color filters 26 are respectively formed on the electrode forming surface 15 a and in regions partitioned by the black matrix 25, that is, regions facing the pixel electrodes 22. The color filter 26 transmits light of a specific wavelength from the light from the liquid crystal LC, and converts the light from the backlight 11 into colored light.

A common overcoat layer 27 is laminated below the black matrix 25 and the color filter 26. The overcoat layer 27 is a thin film made of a light-transmitting resin that transmits light from the element substrate 14 side, and flattens the entire surface of the counter substrate 15. A light transmissive counter electrode 28 is laminated below the overcoat layer 27. The counter electrode 28 is
It is connected to the scanning line driving circuit 19 and receives a predetermined common potential.

A plurality of ribs 30 as convex portions are formed below the counter electrode 28. Each rib 30
Are convex grooves formed over substantially the entire counter electrode 28, and are formed along the slits 22S (two-dot chain lines in FIG. 3) when viewed from the normal direction (anti-Z direction) of the counter substrate 15. Has been. That is, each rib 30 is formed in a ninety-nine fold shape along the Y direction, and is formed along a direction inclined by an inclination angle θ (90> θ ≧ 0) with respect to the Y direction.

Each rib 30 divides the alignment state of liquid crystal molecules located in the vicinity by slopes protruding from the surface of the counter electrode 28. That is, when the liquid crystal molecules are aligned between the state in which the liquid crystal molecules are aligned vertically and the state in which they are horizontally aligned, each rib 30 divides the direction in which the liquid crystal molecules are inclined on the upper side of the counter electrode 28. Let For example, the rib 30 tilts the liquid crystal molecules to the right in the right region and tilts the liquid crystal molecules to the left in the left region. This
The liquid crystal display device 10 can increase the viewing angle by dividing the alignment state of the liquid crystal molecules.

An alignment film 31 is laminated above the counter electrode 28 and each rib 30. Similar to the alignment film 23, the alignment film 31 is a thin film made of an alignment polymer such as alignment polyimide, and defines the alignment state of the liquid crystal LC in the vicinity of the corresponding color filter 26. The alignment film 31 is formed by discharging the alignment film ink in which the alignment polymer is dispersed as droplets onto the entire upper side of the counter electrode 28 and the ribs 30 and drying the liquid film composed of a plurality of droplets.

In a part of the alignment film 31, a raised portion FLO (a region with a gradation in FIG. 3) as a stepped portion extending in the Y direction is formed so as to intersect the rib 30. Uplift FLO
Is a stepped portion protruding from the surrounding alignment film 31 and is formed so as to spread along the intersecting ribs 30.

The raised portion FLO divides the alignment of liquid crystal molecules located in the vicinity by an inclined surface raised from the periphery. The raised portion FLO extending in the Y direction divides the direction in which the liquid crystal molecules incline along the Y direction, and the alignment division of the liquid crystal molecules is divided by the intersecting ribs 30. Therefore, the raised portion FLO divides the alignment state of the liquid crystal molecules in a direction different from that of the ribs 30 and enlarges the viewing angle of the liquid crystal display device 10. Moreover, the raised portion FLO intersects the rib 30 at an inclination angle θ, thereby avoiding continuous alignment division along the Y direction, and the liquid crystal display device 10.
Display unevenness along the Y direction.

The scanning line driving circuit 19 selects each scanning line Lx one by one based on line sequential scanning at a predetermined timing, and turns on the control elements of each pixel 20 only during the selection period. The switching element 21 in the on state receives a data signal based on the display data from the data line Ly,
A data signal is output to the corresponding pixel electrode 22. Each pixel electrode 22 is connected to each pixel electrode 2
2 and the counter electrode 28, the alignment state of the corresponding liquid crystal LC is modulated, and the polarization state of the light from the optical substrate 17 is modulated for each pixel 20. The modulated light is converted into colored light by the corresponding color filter 26, and a full color image without display unevenness is displayed.

Next, a method for manufacturing the liquid crystal display device 10 will be described with reference to FIGS.
First, the droplet discharge device 35 for forming the alignment films 23 and 31 will be described. In addition,
Since the alignment film 23 and the alignment film 31 are manufactured by using the same manufacturing method, for convenience of description, a mode for manufacturing the alignment film 31 will be described below.

In FIG. 4, the droplet discharge device 35 is provided with a base 36 formed in a rectangular parallelepiped shape. A pair of guide grooves 37 extending along the longitudinal direction (Y direction) is formed on the upper surface of the base 36. A pair of guide grooves 37 is attached with a substrate stage 38 that is drivingly connected to an output shaft of a Y-axis motor provided in the base 36.

The substrate stage 38 positions and fixes the counter substrate 15 with the counter electrode 28 facing upward. The substrate stage 38 moves in the Y direction or anti-Y direction at a predetermined speed along the guide groove 37 when the Y-axis motor rotates forward or reversely, and the counter substrate 15 positioned and fixed is moved in the Y direction or anti-Y.
Scan in the direction.

A guide member 39 formed in a gate shape is installed above the base 36. An ink tank 41 is disposed above the guide member 39. The ink tank 41 stores the alignment film ink Ik, and supplies the alignment film ink Ik adjusted to a predetermined pressure toward the ejection head.

The guide member 39 is formed with a pair of upper and lower guide rails 42 extending in the X direction.
A pair of upper and lower guide rails 42 is attached with a carriage 43 that is drivingly connected to an output shaft of an X-axis motor MX provided in the guide member 39. A substantially rectangular parallelepiped discharge head H extending in the X direction is mounted below the carriage 43. The carriage 43 moves in the X direction or anti-X direction along the guide rail 42 when the X-axis motor rotates forward or reverse, and scans the mounted discharge head H in the X direction or anti-X direction.

FIG. 5 is a view of the ejection head H as viewed from below (the counter substrate 15). FIG. 6 is a view of the ejection head H as seen from the Y direction.
In FIG. 5, a nozzle plate 44 is disposed above the discharge head H (on the substrate stage 38 side).
Is provided. A nozzle forming surface 44a parallel to the counter substrate 15 is formed on the upper surface of the nozzle plate 44, and a plurality of nozzles N penetrating in the normal direction of the nozzle forming surface 44a are along the X direction on the nozzle forming surface 44a. Are arranged at equal intervals to constitute one nozzle row. A head substrate 45 is provided below the ejection head H, and an input terminal 45 a is provided at one end of the head substrate 45. A predetermined drive waveform signal for driving the ejection head H is input to the input terminal 45a.

In FIG. 6, the ejection head H has cavities 46 that communicate with the ink tanks 41 above the nozzles N, respectively. Each cavity 46 supplies the alignment film ink Ik derived from the ink tank 41 to the corresponding nozzle N, respectively. A vibration plate 47 that can vibrate in the vertical direction is attached to the upper side of each cavity 46 so that the volume of the corresponding cavity 46 can be enlarged or reduced. A piezoelectric element PZ corresponding to each nozzle N is disposed on the upper side of the vibration plate 47. When each piezoelectric element PZ receives a drive waveform signal for driving the piezoelectric element PZ, the piezoelectric element PZ contracts and expands in the vertical direction and vibrates the corresponding diaphragm 47. When the corresponding vibration plate 47 vibrates, the cavity 46 vibrates the meniscus inside the corresponding nozzle N in the vertical direction, and discharges a predetermined weight of the alignment film ink Ik as a droplet D from the nozzle N. The discharged droplets D fly toward the counter substrate 15 and land on the upper surface of the counter electrode 28 (hereinafter simply referred to as the discharge surface 28a).

In FIG. 6, the ejection surface 28a is virtually divided by a dot pattern grid indicated by a one-dot chain line. The dot pattern grid is a grid defined by the discharge pitch Py in the Y direction and the discharge pitch Px in the X direction. The ejection pitch Py is a value defined based on the ejection frequency of the droplets D and the scanning speed of the substrate stage 38, and is the minimum ejection interval of the droplets D defined along the Y direction. The discharge pitch Px is defined by the same size as the nozzle N formation pitch. The ejection / non-ejection of the droplet D is defined for each grid point P of the dot pattern grid. The nozzle N that discharges the droplet D is defined as the nozzle N that passes above the lattice point P.

When the counter substrate 15 is scanned in the Y direction, the ejection head H drives each piezoelectric element PZ and ejects a droplet D from the corresponding nozzle N each time the lattice point P is located immediately below the nozzle N. Let The discharged droplets D land on the counter electrode 28 and discharge surface 28a.
The first belt-shaped first layer extending in the Y direction of the counter substrate 15 and extending over substantially the entire width in the Y direction.
A liquid film FL1 is formed.

At this time, in the first liquid film FL1, the alignment film ink Ik positioned at the end thereof is guided to each rib 30 and the outer edge thereof is dispersed in the extending direction of each rib 30.
In FIG. 7, when the counter substrate 15 having the first liquid film FL1 is scanned in the anti-Y direction, the ejection head H is line-breaked in the X direction and the lattice point P is again positioned immediately below the nozzle N. In addition, each piezoelectric element PZ is driven to discharge a droplet D from the corresponding nozzle N. Each discharged droplet D lands on the counter electrode 28 and spreads wet along the surface direction of the discharge surface 28a, thereby forming a strip-shaped second liquid film FL2 extending over substantially the entire width of the counter substrate 15 in the Y direction. To do.

At this time, the boundary between the first liquid film FL1 and the second liquid film FL2 is in accordance with the difference in the dry state.
A raised portion FLO protruding from the periphery is formed along the Y direction. On the other hand, the boundary between the first liquid film FL1 and the second liquid film FL2 that intersects the rib 30 is such that the alignment film ink Ik is guided to each rib 30, and the bulge extends in the direction in which the rib 30 extends. Disperse. Therefore, at the boundary between the first liquid film FL1 and the second liquid film FL2, the step of the film thickness is reduced and the region of the raised portion FLO is dispersed as much as the ribs 30 lead the alignment film ink Ik.

Next, the electrical configuration of the droplet discharge device 35 configured as described above will be described with reference to FIG.
In FIG. 8, the control unit 51 includes a CPU, a ROM, a RAM, and the like. The control unit 51 moves the substrate stage 38 and the carriage 43 according to various data and various programs stored in a RAM, a ROM, and the like, and drives and controls the ejection head H.

The control unit 51 includes an input / output device 5 having operation switches such as a start switch and a stop switch.
2 is connected. The input / output device 52 is an external computer having, for example, a CPU, RAM, ROM, hard disk, liquid crystal display, and the like. The input / output device 52 is a ROM.
Alternatively, various control signals for driving the droplet discharge device 35 are output to the control unit 51 in accordance with a control program stored in the hard disk. The control unit 51 receives drawing data Ip for drawing the alignment film 31 (the first liquid film FL1 and the second liquid film FL2) from the input / output device 52.

The control unit 51 develops and stores the drawing data Ip from the input / output device 52 as dot pattern data PD. Here, the dot pattern data PD defines a dot pattern grid composed of an ejection pitch Px in the X direction and an ejection pitch Py in the Y direction (a direction inclined by an inclination angle θ with respect to the longitudinal direction of the rib 30). The dot pattern data PD is data for associating each bit value (0 or 1) with each grid point P of the dot pattern grid,
The piezoelectric element PZ is turned on or off according to the value of each bit. That is, the dot pattern data PD defines ON or OFF of the piezoelectric element PZ for each predetermined ejection frequency according to the ejection pitch Py when the counter substrate 15 is scanned in the Y direction or the anti-Y direction.

When the dot pattern data PD corresponding to one scan of the substrate stage 38 is developed, the control unit 51 generates serial pattern data SI synchronized with a predetermined transfer clock using the dot pattern data PD, and the head drive circuit 58. Serial transfer to The serial pattern data SI has bit values for the number of nozzles N for defining ejection / non-ejection of the droplet D, and is sequentially generated for each ejection cycle.

The control unit 51 is connected to the X-axis motor drive circuit 53 and outputs a drive control signal corresponding to the X-axis motor drive circuit 53. In response to the drive control signal from the control unit 51, the X-axis motor drive circuit 53 rotates the X-axis motor MX in the normal direction or the reverse direction, and scans the carriage 43 in the X direction or the opposite X direction.

The control unit 51 is connected to the Y-axis motor drive circuit 54 and outputs a drive control signal corresponding to the Y-axis motor drive circuit 54. The Y-axis motor drive circuit 54 rotates the Y-axis motor MY forward or backward in response to a drive control signal from the control unit 51, and scans the substrate stage 38 in the Y direction or the anti-Y direction.

The control unit 51 is connected to the X-axis motor rotation detector 55 and receives a detection signal from the X-axis motor rotation detector 55. The control unit 51 calculates the movement direction and movement amount of the carriage 43, that is, the movement direction and movement amount of the discharge head H, based on the detection signal from the X-axis motor rotation detector 55. The control unit 51 places each nozzle N on the scanning path of the lattice point P based on the calculation result.

The control unit 51 is connected to the Y-axis motor rotation detector 56 and receives a detection signal from the Y-axis motor rotation detector 56. Based on the detection signal from the Y-axis motor rotation detector 56, the controller 51 calculates the movement direction and movement amount of the substrate stage 38, that is, the movement direction and movement amount of the counter substrate 15. Based on the calculation result, the control unit 51 outputs the ejection timing signal LP when each grid point P is located immediately below the corresponding nozzle N.

The control unit 51 is connected to a substrate detection device 57 that detects the edge of the counter substrate 15 and receives a detection signal from the substrate detection device 57. The control unit 51 calculates the initial position of the counter substrate 15 based on the detection signal from the substrate detection device 57.

The control unit 51 is connected to the head drive circuit 58 and sends a latch signal L to the head drive circuit 58.
AT and discharge timing signal LP are input. In addition, the control unit 51 synchronizes the drive waveform signal COM for driving the piezoelectric element PZ with the ejection timing signal LP, and thereby the head drive circuit 58.
To enter.

The head drive circuit 58 latches the serial pattern data SI from the control unit 51 and performs serial / parallel conversion each time the latch signal LAT is received. The head drive circuit 58
When receiving the ejection timing signal LP from the control unit 51, the drive waveform signal COM is supplied to each of the piezoelectric elements PZ selected based on the serial / parallel converted data.

Next, a method for forming the alignment film 31 using the droplet discharge device 35 will be described.
First, as shown in FIG. 4, the counter substrate 15 with the counter electrode 28 facing upward is formed on the substrate stage 3.
8 and placed in the anti-Y direction of the carriage 43. Next, the control unit 51 receives the drawing data Ip from the input / output device 52 and converts the drawing data Ip into the dot pattern data P.
Expand to D and store. In addition, the control unit 51 drives and controls the X-axis motor MX via the X-axis motor drive circuit 53, and each nozzle N is placed on the scanning path of each lattice point P corresponding to the first liquid film FL1.
In other words, the carriage 43 is set for the first liquid film FL1.

When the carriage 43 is set, the control unit 51 drives and controls the Y-axis motor MY via the Y-axis motor drive circuit 54 and starts scanning the counter substrate 15 in the Y direction. When the controller 51 starts scanning the counter substrate 15 in the Y direction, the substrate detector 57 and the Y-axis motor rotation detector 5 are started.
Based on the detection signal from 6, it is determined whether or not each lattice point P has reached directly below the nozzle N.

During this time, the control unit 51 develops the dot pattern data PD corresponding to one scan, sequentially generates serial pattern data SI synchronized with the transfer clock, and serially transfers it to the head drive circuit 58. Further, the control unit 51 transfers the serial pattern data SI every time
The latch signal LAT is input to the head drive circuit 58, and the head drive circuit 58 performs serial / parallel conversion of the serial pattern data SI. The control unit 51 inputs the ejection timing signal LP and the drive waveform signal COM to the head drive circuit 58 every time each lattice point P reaches just below the nozzle N.

Whenever the ejection timing signal LP and the drive waveform signal COM are input to the head drive circuit 58, the control unit 51 drives each piezoelectric element PZ selected based on the serial pattern data SI via the head drive circuit 58. A waveform signal COM is supplied. And the control part 5
1 indicates that the droplets D are simultaneously ejected from the nozzles N selected based on the dot pattern data PD toward the corresponding lattice points P, and the first liquid film FL in a band shape along the direction intersecting the ribs 30.
1 is formed.

When the control unit 51 finishes scanning the counter substrate 15 in the Y direction, the X-axis motor drive circuit 53 is finished.
The X-axis motor MX is driven and controlled, and each nozzle N is arranged on the scanning path of each lattice point P corresponding to the second liquid film FL2, that is, the carriage 43 is set for the second liquid film FL2. .

When the carriage 43 is set, the control unit 51 drives and controls the Y-axis motor MY via the Y-axis motor drive circuit 54 and starts scanning the counter substrate 15 in the anti-Y direction. The control unit 51
When scanning of the counter substrate 15 in the anti-Y direction is started, it is determined whether or not each lattice point P has reached directly below the nozzle N based on detection signals from the substrate detection device 57 and the Y-axis motor rotation detector 56. To do.

During this time, the control unit 51 develops the dot pattern data PD corresponding to one scan, sequentially generates serial pattern data SI synchronized with the transfer clock, and serially transfers it to the head drive circuit 58. Further, the control unit 51 transfers the serial pattern data SI every time
The latch signal LAT is input to the head drive circuit 58, and the head drive circuit 58 performs serial / parallel conversion of the serial pattern data SI. The control unit 51 inputs the ejection timing signal LP and the drive waveform signal COM to the head drive circuit 58 every time each grid point P reaches just below the nozzle N.

Each time the controller 51 inputs the ejection timing signal LP and the drive waveform signal COM to the head drive circuit 58, the drive waveform is applied to each piezoelectric element PZ selected based on the serial pattern data SI via the head drive circuit 58. The signal COM is supplied. Then, the control unit 51
The droplets D are simultaneously ejected from the nozzles N selected based on the dot pattern data PD toward the corresponding lattice points P, and overlap with the first liquid film FL1 along the direction intersecting the ribs 30. The second liquid film FL2 is formed. As a result, a raised portion FLO intersecting with the rib 30 is formed at the boundary between the first liquid film FL1 and the second liquid film FL2.

Thereafter, similarly, the control unit 51 and the first liquid film FL1 formed by scanning in the Y direction and the anti-Y
The second liquid film FL2 formed by scanning in the direction is alternately overlapped to form a liquid film having a raised portion FLO intersecting the rib 30 on the entire discharge surface 28a. The alignment film 31 that reduces display unevenness can be formed by drying the liquid film and performing a rubbing process.

Next, effects of the present embodiment configured as described above will be described below.
(1) According to the embodiment, the counter substrate 15 is scanned in the Y direction, and the first liquid film FL1 is formed along the direction intersecting the ribs 30. Further, the carriage 43 is line-turned in the X direction, and the counter substrate 15 is scanned in the anti-Y direction to form the second liquid film FL2 along the direction intersecting the ribs 30. Then, the raised portion FLO where the first liquid film FL1 and the second liquid film FL2 overlap is formed on the rib 3
It was formed along the direction crossing zero.

Therefore, the raised portion FLO can expand the viewing angle of the liquid crystal display device 10 by the amount that divides the alignment state of the liquid crystal molecules along the Y direction, and can extend in the Y direction by the amount that intersects the ribs 30. It is possible to avoid continuous alignment division along. As a result, the liquid crystal display device 1
The display unevenness of 0 can be reduced.

(2) In addition, the raised portion FLO intersecting with the rib 30 is guided by the alignment film ink Ik to each rib 30 and disperses the raised portion in the extending direction of the rib 30. That is, as the ribs 30 lead the alignment film ink Ik, the film thickness level difference of the alignment film 31 can be reduced and the region of the raised portion FLO can be dispersed. Therefore, the continuous alignment division along the Y direction can be further eliminated, and the display unevenness of the liquid crystal display device 10 can be more reliably reduced.

(Second embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the rib 30 and the alignment film 31 of the first embodiment are changed. Therefore, in the following, the changes will be described in detail.

In FIG. 9, an alignment film 31 is formed below the counter electrode 28, and a rib 30 protruding from the alignment film 31 is formed below the alignment film 31.
Similar to the first embodiment, the alignment film 31 is a thin film made of an alignment polymer such as alignment polyimide, and defines the alignment state of liquid crystal molecules. The alignment film 31 has a raised portion FLO (region with a gradation in FIG. 9) that continuously rises over the entire width of the counter substrate 15 in the Y direction.

The alignment film 31 is the same as the first liquid film FL1 made of the alignment film ink Ik with respect to the counter electrode 28 without the rib 30 using the droplet discharge device 35 shown in the first embodiment. It is formed by sequentially drawing the second liquid film FL2 made of the ink Ik. The alignment film 31 is rubbed without the ribs 30 after these liquid films are dried. Thereby, the alignment film 31 can stabilize the rubbing state and can stabilize the alignment state of the liquid crystal molecules as compared with the case where the rubbing treatment is performed in a state having the ribs 30.

Each rib 30 has a raised portion FLO as viewed from the normal direction (anti-Z direction) of the counter substrate 15.
Is formed in a 99-fold shape along the Y direction. Each rib 30 is formed by forming a coating film made of, for example, a photosensitive resin material on the entire surface of the alignment film 31 that has been rubbed, and exposing and developing the coating film.

Each rib 30 divides the alignment state of liquid crystal molecules located in the vicinity by slopes protruding from the surface of the alignment film 31. That is, as in the first embodiment, each rib 30 divides the direction in which the liquid crystal molecules incline on the upper side of the alignment film 31 to enlarge the viewing angle of the liquid crystal display device 10.

Even in this configuration, the raised portion FLO is formed by the inclined surface raised from the surrounding alignment film 31.
The alignment of liquid crystal molecules located in the vicinity is divided. The raised portion FLO extending in the Y direction divides the direction in which the liquid crystal molecules incline along the Y direction, and divides the alignment division of the liquid crystal molecules by the intersecting ribs 30. Therefore, the raised portion FLO enlarges the viewing angle by the amount of dividing the alignment state of the liquid crystal molecules, and avoids the continuous alignment division along the Y direction by the amount intersecting with the rib 30, thereby displaying the liquid crystal display. Display unevenness of the device 10 can be reduced.

In addition, you may change the said embodiment as follows.
In the first embodiment, the form in which the alignment film 31 is formed using the counter substrate 15 having the ribs 30 has been described. For example, the alignment film 23 may be formed using the element substrate 14 having the slits 22S. That is, when the element substrate 14 is placed on the substrate stage 38, the extending direction of the slit 22S is inclined by the inclination angle θ with respect to the Y direction, and intersects with the scanning direction (Y direction) of the nozzle N. Good.

According to this configuration, the droplets D that land on the pixel electrode 22 are guided along the inside of the slit 22S, and the outer edge of the alignment film ink Ik is dispersed in the extending direction of the slit 22S. Therefore, at the boundary between the first liquid film FL1 and the second liquid film FL2, the slits 22S are formed by the alignment film ink I.
The step of the film thickness is reduced by the amount corresponding to k, and the region of the raised portion FLO is dispersed. Therefore, display unevenness due to the alignment film 23 can be reduced, and consequently, display unevenness of the liquid crystal display device 10 can be further reduced.

In the above embodiment, the droplet discharge device 35 is provided with one discharge head H, and the discharge head H is configured to perform line feed scanning. For example, a plurality of ejection heads H may be arranged in the X direction, and the plurality of ejection heads H may be scanned only once with respect to the counter substrate 15.
That is, as shown in FIG. 10, when viewed from the substrate stage 38, a plurality of discharge heads H are arranged in a staggered manner along the X direction, and the plurality of discharge heads H are scanned only once with respect to the counter substrate 15. It may be. Alternatively, as shown in FIG. 11, when viewed from the substrate stage 38, a plurality of ejection heads H may be arranged in a step shape, and the plurality of ejection heads H may be scanned with respect to the counter substrate 15 only once. .

According to this configuration, when the substrate stage is scanned in the Y direction, the discharge head H positioned relatively in the anti-Y direction forms a liquid film in advance compared to the other discharge heads H. Also,
The ejection head H relatively positioned in the Y direction subsequently forms a liquid film as compared with the other ejection heads H. And the area | region (superimposition area | region S) where the preceding liquid film and the subsequent liquid film overlap
In addition, the raised portion FLO is formed, and the raised portion FLO is dispersed and divided by the rib 30.

In the above embodiment, the rib 30 is embodied in a 99-fold shape. For example, the rib 30 may be embodied in a linear shape that intersects the Y direction, and may be any shape that extends in a direction intersecting the scanning direction of the nozzle N.

In the above embodiment, the relative movement unit is embodied in the substrate stage 38. Not only this,
For example, the relative movement means may be embodied in the carriage 43 or both the substrate stage 38 and the carriage 43. That is, the nozzle N for the slit 22S or the rib 30
The scanning direction may be any configuration that intersects the direction in which the slits 22S or the ribs 30 extend.

In the above embodiment, the ejection head H has a single nozzle row. For example, the ejection head H may have two or more nozzle rows.

The perspective view which shows a liquid crystal display device. (A), (b) is the top view and side sectional view which respectively show an element substrate. (A), (b) is the top view and side sectional view which respectively show a counter substrate. The perspective view which shows a droplet discharge apparatus. The perspective view which shows an ejection head. (A) is principal part sectional drawing which shows a discharge head, (b) is a top view of the opposing board | substrate which shows discharge operation. (A) is principal part sectional drawing which shows a discharge head, (b) is a top view of the opposing board | substrate which shows discharge operation. The electric block circuit diagram which shows the electric constitution of a droplet discharge apparatus. The top view and side sectional view which show the counter substrate of 2nd embodiment. FIG. 6 is a plan view showing the arrangement of ejection heads in a modified example. FIG. 6 is a plan view showing the arrangement of ejection heads in a modified example.

Explanation of symbols

D: Droplet, FLO: Raised portion as stepped portion, H ... Discharge head, N ... Nozzle, 10 ... Liquid crystal display device, 15 ... Counter substrate as transparent substrate, 23, 31 ... Alignment film, 35 ... Droplet discharge apparatus,
38 ... Substrate stage constituting relative movement means, 51 ... control unit.

Claims (7)

A method of manufacturing a liquid crystal display device having an alignment film on a transparent substrate,
An alignment head material having a plurality of nozzles arranged in one direction and the transparent substrate are relatively moved along another direction intersecting the one direction, and the alignment film material is directed from the plurality of nozzles toward the transparent substrate. A step of discharging a plurality of liquid droplets containing, and drying the plurality of liquid droplets landed on the transparent substrate;
Forming a stepped portion extending in a direction crossing the other direction on the transparent substrate;
A method for manufacturing a liquid crystal display device, comprising: It is a manufacturing method of the liquid crystal display device according to claim 1,
After forming the stepped portion, discharging the plurality of droplets containing the alignment film material toward the transparent substrate, drying the plurality of droplets that have landed on the transparent substrate, and performing an alignment treatment;
A method for manufacturing a liquid crystal display device. It is a manufacturing method of the liquid crystal display device according to claim 1,
Before forming the stepped portion, the plurality of droplets containing the alignment film material are ejected toward the transparent substrate, and the plurality of droplets that have landed on the transparent substrate are dried and subjected to alignment treatment. ,
A method for manufacturing a liquid crystal display device. It is a manufacturing method of the liquid crystal display device according to any one of claims 1 to 3,
The step portion is a convex portion that regulates the alignment direction of liquid crystal molecules;
A method for manufacturing a liquid crystal display device. An ejection head having a plurality of nozzles arranged in one direction, and ejecting droplets containing alignment film material from each of the plurality of nozzles;
A relative movement means for relatively moving the transparent substrate having a stepped portion extending in the other direction and the ejection head in a direction intersecting the other direction;
Control for driving the relative movement means to move the transparent substrate and the discharge head relative to each other, and driving the discharge head to discharge a plurality of droplets from each of the plurality of nozzles toward the transparent substrate. And
A droplet discharge apparatus comprising: The droplet discharge device according to claim 5,
The relative moving means is
A substrate stage on which the transparent substrate is placed and the transparent substrate is moved in a direction perpendicular to the one direction;
A droplet discharge device characterized by the above. The droplet discharge device according to claim 5 or 6,
The step portion is a convex portion that regulates the alignment direction of liquid crystal molecules;
A droplet discharge device characterized by the above.

Images