JP2010169926A - Method for forming alignment layer and apparatus for forming alignment layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for forming an alignment layer, controlling the amount of liquid drops of an alignment layer material to be uniform, the material dropped from a plurality of nozzles disposed in an inkjet head. <P>SOLUTION: The apparatus for forming the alignment layer has an inkjet head disposed as relatively movable in the moving direction of the dropping process with respect to the substrate of a liquid crystal display panel, and forms an alignment layer by spreading the liquid drops of an alignment layer material dropped onto the substrate surface from a plurality of nozzles arranged in a direction intersecting the moving direction of the dropping process of the inkjet head. The apparatus is equipped with: a film thickness measuring means that measures the film thickness of the alignment film formed on the substrate surface, along a direction perpendicular to the moving direction of the dropping process; and a dropping amount adjusting means that increases or decreases the dropping amount of the alignment layer material from each nozzle on the basis of the difference between the desired film thickness and the film thickness in the position where the alignment layer material is dropped by each nozzle measured by the film thickness measuring means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an alignment film forming method and an alignment film forming apparatus for forming an alignment film by dropping an alignment film material onto a substrate for a liquid crystal display panel by an inkjet method.

  In recent years, liquid crystal display panels have been widely used as display units for home appliances such as computers and televisions. In general, a liquid crystal display panel has a configuration in which a pair of substrates, which are a thin film transistor (TFT) array substrate and a color filter (CF) substrate, are arranged in parallel to each other at a predetermined interval, and liquid crystal is filled between the substrates. There is no. A plurality of pixel electrodes are formed in a matrix on the TFT array substrate, and a common electrode is formed on almost the entire surface of the CF substrate, and the orientation of the liquid crystal can be controlled by changing the voltage applied between these electrodes. Can be done.

  Usually, in order to align the alignment of the liquid crystal, an alignment film made of an organic material such as polyimide is formed so as to cover the pixel electrode and the common electrode. Such an alignment film is formed on the substrate surface using an inkjet head as shown in FIG. 7 in addition to a method in which a thin film made of an alignment film material is transferred to a substrate surface on which an electrode is formed by a rotating roller. There is a method of forming an alignment film material by dropping (for example, Patent Document 1 below).

  As shown in the figure, each of the inkjet heads 2 arranged in a staggered pattern has a plurality of nozzles 2 d arranged at a predetermined pitch P along the X direction. The droplets 20, 20, 20, 20,... Of the alignment film material can be continuously dropped from each nozzle 2 d while being relatively moved in the direction.

  Each droplet 20 of the alignment film material dropped from the nozzle 2d spreads on the surface of the substrate 60 at the moment of landing, and when the adjacent droplets 20 come into contact with each other, the droplets 20 are connected from the contact position. Together, the alignment film material is formed as a single thin film spread uniformly on the surface of the substrate 60. Thereafter, when a solvent other than the alignment film material contained in the droplets 20 is removed through a predetermined process such as drying, an alignment film having a predetermined film thickness is obtained on the surface of the substrate 60.

  In this case, for example, the inter-nozzle pitch P, which is the interval between the adjacent nozzles 2d and 2d, is a length of several hundred μm, and the droplets 20 of the alignment film material dropped from the adjacent nozzles 2d and 2d are shown in FIG. In order to avoid overlapping, as shown in FIG. 5, for example, shifting the nozzles 2d in the arrangement direction (X direction) by the length of half to 1/4 (half pitch to 1/4 pitch) of the inter-nozzle pitch P By repeating each time the head 2 is moved a plurality of times in the dropping movement direction (Y direction), the droplets 20 are integrally connected.

  More specifically, for example, when the inter-nozzle pitch P is 800 μm and it is shifted in the X direction by a quarter length thereof, that is, 200 μm, as shown in FIG. The movement for dripping is performed four times. The procedure of the dropping operation in this case will be described.

  First, as shown in FIG. 8, by the movement of the arrow 31 downward in the Y direction for the first time of the inkjet head 2, a row 21 of droplets 20 of alignment film material continuous along the Y direction on the surface of the substrate 60. Form. Next, as shown in FIG. 9, the ink jet head 2 is shifted by the movement of the arrow 32 to the right in the X direction by a length (1/4 pitch) of the inter-nozzle pitch P of the ink jet head 2. By the second movement of the arrow 33 upward in the Y direction, a row 22 of droplets 20 of the alignment film material is formed on the surface of the substrate 60.

  Next, as shown in FIG. 10, after shifting by the movement of the arrow 34 to the right in the X direction by a length of 1/4 of the inter-nozzle pitch P of the inkjet head 2, the third downward direction of the inkjet head 2 in the Y direction. By moving the arrow 35 to the side, a row 23 of droplets 20 of alignment film material is formed on the surface of the substrate 60. Then, as shown in FIG. 11, after shifting by the movement of the arrow 36 to the right in the X direction by a length of ¼ of the inter-nozzle pitch P of the inkjet head 2, the inkjet head 2 moves upward in the fourth Y direction. By moving the arrow 37, a row 24 of droplets 20 of alignment film material is formed on the surface of the substrate 60.

  That is, the plurality of alignment film material droplets 20 formed by dropping on the surface of the substrate 60 by the first movement (arrow 31) of the inkjet head 2 to the substrate 60 as shown in FIG. The second, third, fourth and Y directions while shifting the inkjet head 2 in the X direction (arrows 32, 34, 36) by a predetermined shift amount (1/4 pitch) so as to fill the space between the rows 21 By moving to (arrows 33, 35, 37), the rows 21, 22, 23, 24 of the droplets 20 of the alignment film material are formed as shown in FIG. The rows 21, 22, 23, and 24 of the droplets 20 are connected so that they can be integrated.

  In this way, by reciprocating the inkjet head 2 in the Y direction while shifting in the X direction, the rows 21, 22, 23, and 24 of the liquid crystal droplets 20 adjacent to each other are connected to each other. When the droplets 20 are integrated and dried, an alignment film is formed as a single thin film on the surface of the substrate 60.

JP 2001-42330 A

  However, among the plurality of nozzles 2d provided in each inkjet head 2, the amount of droplets 20 dripped from the nozzle 2d is small or large due to problems such as clogging of any nozzle 2d or variations in the amount of dripping. In some cases, the amount of dripping is not appropriate.

  If there is a defective nozzle with an inappropriate drop amount, the rows 21, 22, 23, 23, 23, 23, 23, 23 of the alignment film material 20 are moved by two reciprocations in the Y direction while shifting the inkjet head 2 described above in the X direction. In the case of forming 24, as shown in FIG. 12, the alignment film material droplet rows 21, 22, 23, 24 formed by dropping from the defective nozzles 2h, 2h (nozzles surrounded by dotted lines in the figure) , They are formed continuously so as to be adjacent to each other.

  Therefore, for example, as shown in the drawing, all of the four droplet rows 21, 22, 23, 24 in the dropping region 26b corresponding to the dropping position of the left defective nozzle 2h are increased, or the right defective nozzle 2h As a result of the decrease in all the four droplet rows 21, 22, 23, 24 in the dropping region 26i corresponding to the dropping position, the alignment film material in this portion may be more or less than the other portions. Will occur.

  When a substrate having a portion where the amount of the alignment film material is not dropped is subjected to a predetermined process such as drying, as shown in FIG. 4, the film thickness of the dropping region 26b and the dropping region 26i is different from that of the other. An alignment film 62 having a non-uniform thickness than the thickness of the portion is formed on the substrate surface, and this is displayed as streak-like unevenness in the image display of the liquid crystal display panel 40 as shown in FIG. The unevenness 41 was caused.

  If there is a part of the substrate surface where the amount of the alignment film material dropped is not appropriate, a certain amount of time is required until the amount of the alignment film material in this part becomes uniform with the amount of the alignment film material in the other part. Although it is conceivable to leave it or to vibrate the substrate so as to be uniform, there is a problem that the manufacturing cost increases due to an increase in the number of processes.

  Therefore, the problem to be solved by the present invention is to provide an alignment film forming method and an alignment film forming apparatus capable of uniformizing the amount of alignment film material dropped from a plurality of nozzles provided in an inkjet head. Is to provide.

  In order to solve the above-described problems, the present invention provides an inkjet head that is movable relative to a substrate for a liquid crystal display panel in a dropping movement direction, and is arranged along a direction that intersects the dropping movement direction of the inkjet head. An alignment film forming method for forming an alignment film by spreading droplets of alignment film material dropped on the substrate surface from a plurality of nozzles provided, wherein the film thickness of the alignment film formed on the substrate surface is Based on the difference between the film thickness measurement process to be measured and the film thickness at the alignment film material dropping position of each nozzle measured by the film thickness measurement process and the desired film thickness, the amount of the alignment film material dripped from each nozzle is determined. The gist of the present invention is to provide a dropping amount adjusting step for increasing or decreasing.

  According to the method for forming an alignment film having such a configuration, after the alignment film material is formed by dropping the alignment film material from the nozzle of the ink jet head onto the surface of the substrate for the liquid crystal display panel, and after measuring the film thickness of the alignment film The adjustment of increasing or decreasing the amount of alignment film material from each nozzle by calculating the difference between the film thickness of the film thickness measurement data and the desired desired film thickness for each alignment film material dropping position of each nozzle. Done. As described above, the amount of the alignment film material dropped from each nozzle of the inkjet head is adjusted (corrected) so that the alignment film material droplets dropped from the defective nozzle are adjacent to each other as described above. It is possible to prevent a portion where the alignment film is continuously non-uniformly formed so as to fit.

  In this case, in the film thickness measurement step, if the film thickness of the alignment film formed on the substrate surface is measured along a direction orthogonal to the dropping movement direction, the alignment film material dropping position of each nozzle is determined. Therefore, it is easy to calculate the difference between the film thickness measurement data and the desired film thickness, and the film thickness of the alignment film dropped by each nozzle can be measured efficiently. Can be reduced, and the measurement time can be shortened.

  Further, in the film thickness measurement step, for example, a plurality of film thickness measurement data measured at a plurality of locations can be obtained by measuring a plurality of locations including a substantially central portion of the alignment film formed on the substrate surface. The accuracy of film thickness measurement can be improved by averaging the film thickness values. Also, it is possible to detect a change in the thickness of the alignment film along the dropping movement direction, such as when the amount of the alignment film material dropped from any of the nozzles changes while the inkjet head is dropping. Therefore, it becomes easy to identify a defective nozzle in which the dropping amount of the alignment film material changes during the dropping movement.

  In order to solve the above problems, the present invention provides an ink jet head that is movable relative to a liquid crystal display panel substrate in a dropping movement direction, and in a direction intersecting the dropping movement direction of the ink jet head. An alignment film forming apparatus for forming an alignment film by spreading droplets of alignment film material dropped on the substrate surface from a plurality of nozzles disposed along the substrate, wherein the alignment film formed on the substrate surface The film thickness measuring means for measuring the film thickness, and the alignment film material from each nozzle based on the difference between the desired film thickness and the film thickness at the alignment film material dropping position of each nozzle measured by the film thickness measuring means The gist of the invention is that it includes a dropping amount adjusting means for increasing or decreasing the dropping amount.

  According to the alignment film forming apparatus having such a configuration, the alignment film material is dropped from the nozzle of the inkjet head onto the surface of the substrate for the liquid crystal display panel to form the alignment film, and the film thickness of the alignment film is measured. After measuring by means, the difference between the film thickness measurement data thickness and the desired film thickness is calculated for each alignment film material dropping position of each nozzle, and the amount of alignment film material dropped from each nozzle Adjustment for increasing / decreasing is performed by the dropping amount adjusting means. As described above, the amount of the alignment film material dropped from each nozzle of the inkjet head is adjusted (corrected) so that the alignment film material droplets dropped from the defective nozzle are adjacent to each other as described above. It is possible to prevent local formation of a portion where the thickness of the alignment film is not uniform so as to match.

  In this case, if the film thickness measuring unit measures the film thickness of the alignment film formed on the substrate surface along the direction perpendicular to the dropping movement direction, the film is formed for each alignment film material dropping position of each nozzle. It becomes easier to calculate the difference between the film thickness of the thickness measurement data and the target desired film thickness, and the film thickness of the alignment film dropped by each nozzle can be measured efficiently. And the measurement time can be shortened.

  In addition, if the film thickness measuring unit is configured to measure a plurality of locations including a substantially central location of the alignment film formed on the substrate surface, for example, the thickness of a plurality of thickness measurement data measured at a plurality of locations. The accuracy of film thickness measurement can be improved by averaging and using the values of Also, it is possible to detect a change in the thickness of the alignment film along the dropping movement direction, such as when the amount of the alignment film material dropped from any of the nozzles changes while the inkjet head is dropping. Therefore, it becomes easy to identify a defective nozzle in which the dropping amount of the alignment film material changes during the dropping movement.

  According to the alignment film forming method and the alignment film forming apparatus having the above-described configuration, the amount of the alignment film material dropped from each nozzle of the inkjet head is adjusted (corrected) so as to be uniform. It is prevented that a portion having a non-uniform thickness of the alignment film is locally formed so that the alignment film material droplets dropped from the defective nozzle are adjacent to each other. Generation of streak-like display unevenness in the image display of the liquid crystal display panel as shown in FIG. 13 is prevented.

It is the figure which showed schematic structure of the alignment film forming apparatus which is one Embodiment of this invention. It is the figure which showed the waveform of the drive voltage of the nozzle of the inkjet head of FIG. 1 along the time axis. 3 is a graph showing a relationship between an increase rate of a drive voltage of a nozzle of the inkjet head of FIG. It is the cross-sectional view which showed the alignment film formed on the glass substrate with the alignment film formation apparatus. It is the cross-sectional view which showed the alignment film formed on the glass substrate after dropping amount adjustment with the alignment film formation apparatus. It is the figure which showed schematic structure of the liquid crystal display panel. It is the figure which showed the state which dropped the droplet of alignment film material on the substrate surface with the inkjet head. It is the figure which showed the state which formed the 1st row | line | column of the droplet of alignment film material on the substrate surface by the 1st movement of the inkjet head of FIG. It is the figure which showed the state which formed the 2nd row | line | column of the droplet of alignment film material on the substrate surface by the 2nd movement of the inkjet head of FIG. It is the figure which showed the state which formed the 3rd row | line | column of the droplet of alignment film material on the substrate surface by the 3rd movement of the inkjet head of FIG. It is the figure which showed the state which formed the 4th row | line | column of the droplet of alignment film material on the substrate surface by the 4th movement of the inkjet head of FIG. It is the figure which showed the dripping state when the defective nozzle with an inappropriate dripping amount exists in the inkjet head of FIG. It is the figure which showed the case where there exists a stripe-like display nonuniformity in the image display of a liquid crystal display panel.

  Hereinafter, embodiments of an alignment film forming method and an alignment film forming apparatus according to the present invention will be described in detail with reference to the drawings.

  First, a liquid crystal display panel to which the present invention is applied will be described. FIG. 6 shows a schematic configuration of a plan view of a liquid crystal display panel and a cross-sectional view of one pixel. As shown in the drawing, the liquid crystal display panel 40 has a configuration in which a plurality of pixels are arranged in the vertical and horizontal directions. As shown in the sectional view in the figure, the liquid crystal display panel 40 has a configuration in which a liquid crystal 70 is filled between a pair of opposed glass substrates (TFT array substrates) 50 and a glass substrate (CF substrate) 60. It has become. Pixel electrodes 51 provided for each pixel are arranged in a matrix on the lower glass substrate 50, and a common electrode 61 is formed almost entirely under the upper glass substrate 60. Yes.

  A source electrode 52 and a gate electrode (not shown) are formed around each pixel electrode 51 so as to be orthogonal to each other. The source electrode 52 and the gate electrode intersect at the intersection so that the source electrode 52 is on the upper side and the gate electrode is on the lower side via the gate insulating film 55. The TFT is connected to the pixel electrode 51 via a drain electrode (not shown). In this case, the TFT is on / off controlled by the scanning signal voltage supplied from the gate electrode, and the image display signal voltage supplied from the source electrode 52 is applied to the pixel electrode 51 through the drain electrode. It is like that. Further, as shown in the figure, the pixel electrode 51 is surrounded by the source electrode 52 and the gate electrode, and is provided in the region via the interlayer insulating film 54.

  An alignment film 53 is formed on the glass substrate 50 provided with the pixel electrodes 51 so as to cover the pixel electrodes 51. An alignment film 62 is formed on the glass substrate 60 on which the common electrode 61 is formed so as to cover the common electrode 61. These alignment films 53 and 62 are rubbed by rubbing the surfaces of the alignment films 53 and 62 in a predetermined direction using a silk cloth or the like, or photo-alignment processing of irradiating the alignment films 53 and 62 with ultraviolet rays or the like from a predetermined direction. When given, the predetermined alignment characteristics are given to the surfaces of the alignment films 53 and 62, and the alignment of the liquid crystal 70 in contact with the alignment films 53 and 62 can be made uniform.

  A black matrix 63 is formed on the glass substrate 60 on which the common electrode 61 is provided. The black matrix 63 shields the region where the source electrode 52, the gate electrode, and the TFT on the glass substrate 50 side are formed. The glass substrate 60 is provided with a colored layer 64 of any one of red (R), green (G), and blue (B) for each pixel.

  FIG. 1 shows the formation of an alignment film used for forming the alignment film 53 on the glass substrate (TFT array substrate) 50 and the alignment film 62 on the glass substrate (CF substrate) 60 provided in the liquid crystal display panel 40 having the above-described configuration. It is the figure which showed schematic structure of the apparatus. In the following description, a mode in which the alignment film 62 is formed on the glass substrate (CF substrate) 60 will be described, and a mode in which the alignment film 53 is formed on the glass substrate (TFT array substrate) 50 is the same, and is omitted. .

  As shown in the drawing, the alignment film forming apparatus 1 includes a plurality of inkjet heads 2, a dropping stage 3 that allows the glass substrate 60 to move relative to the inkjet heads 2 in the X and Y directions, and each of the inkjet heads 2. A dropping controller 4 for controlling the dropping operation of the alignment film material from the nozzle 2d and the movement of the dropping stage 3 is provided.

  In addition, the alignment film forming apparatus 1 is configured such that the film thickness of the alignment film 62 formed on the surface of the glass substrate 60 by dropping the alignment film material from the inkjet head 2 is a direction (X direction) orthogonal to the dropping movement direction (Y direction). , The measurement stage 6 that enables the glass substrate 60 to move relative to the film thickness measuring device 5 in the XY directions, and the measurement operation and measurement of the film thickness measuring device 5. A film thickness measurement controller 7 for controlling the movement of the stage 6 is provided.

  Furthermore, the alignment film forming apparatus 1 includes a control unit 8 that controls the dropping controller 4 and the film thickness measurement controller 7, a storage unit 9 that stores desired film thickness data targeted for the alignment film, and a film thickness measuring device 5. The drop amount adjustment for increasing or decreasing the drop amount of the alignment film material from each nozzle based on the difference between the film thickness measurement data at the alignment film material dropping position of each nozzle 2d and the target desired film thickness data Part 10 is provided.

  The dropping stage 3 can suck and hold the glass substrate 60 placed on the upper surface thereof, and can move the glass substrate 60 in the XY directions with respect to the inkjet head 2.

  An alignment film solution (for example, 5% polyimide resin, 95% solvent) 12 containing an alignment film material in a supply tank 13 is connected to each inkjet head 2 via a supply pipe 14 and supplied by a supply pump 15. The alignment film solution 12 in the tank 13 is sent out and supplied to each inkjet head 2.

  As shown in the drawing, the inkjet heads 2 are arranged in a staggered pattern along the X direction. In addition, as shown in FIG. 7, a plurality of nozzles 2 d are arranged at a predetermined pitch P in each ink jet head 2 along the X direction. The droplet 20 can be dropped.

  As shown in FIG. 2, the ink jet head 2 includes a head main body 2b in which a liquid storage chamber 2a in which the alignment film solution 12 is stored, and a flexibility provided so as to seal the liquid storage chamber 2a. And a nozzle plate 2e provided in the head body 2b and provided with a nozzle 2d communicating with the liquid storage chamber 2a. The head main body 2b has a prismatic shape, and a plurality of liquid storage chambers 2a are defined in the head main body 2b at predetermined intervals along the longitudinal direction.

  The liquid storage chamber 2a is opened on the upper surface and the lower surface of the head main body 2b, the upper surface opening is closed by the diaphragm 2c, and the lower surface opening is closed by the nozzle plate 2e. The nozzle plate 2e is provided with a nozzle 2d communicating with each liquid storage chamber 2a.

  A plate-like piezoelectric ceramic 2f is fixedly provided on the surface of the vibration plate 2c opposite to the liquid storage chamber 2a, and a predetermined drive voltage is supplied from the dropping controller 4 to the piezoelectric ceramic 2f. It has become. When the piezoelectric ceramic 2f is operated by applying a driving voltage supplied from the dropping controller 4, and the diaphragm 2c is vibrated to apply pressure to the alignment film solution 12 in the liquid storage chamber 2a, the alignment film solution 12 is Each nozzle 2d can be discharged in the form of droplets.

  The head main body 2b is provided with a liquid supply path 2g having one end communicating with the liquid storage chamber 2a. The other end of the liquid supply path 2g opens to the side surface of the head main body 2b and is connected via a supply pipe. Connected to the supply tank 13. As a result, the inside of the liquid storage chamber 2 a is filled with the alignment film solution 12.

  Such an inkjet head 2 includes a piezoelectric ceramic 2f that deforms the volume of the liquid storage chamber 2a filled with the alignment film solution 12 supplied from the liquid supply path 2g in accordance with an applied drive voltage as shown in the figure. By increasing / decreasing the ratio, the droplet 20 of the alignment film solution can be discharged from the nozzle 2d communicated with the liquid storage chamber 2a.

  Specifically, as shown in FIG. 2, when a voltage of VH is applied immediately before the discharge operation from a standby state where the applied voltage to the piezoelectric ceramic 2f is VL, the piezoelectric ceramic 2f is curved and deformed upward. Accordingly, the vibration plate 2c is also displaced upward, the volume of the liquid storage chamber 2a is increased, and the alignment film solution 12 is supplied to the liquid storage chamber 2a through the liquid supply path 2g. Then, when a voltage of VL is applied immediately after that, the piezoelectric ceramic 2f that has been bent and deformed upward is bent and deformed downward. Along with this, the vibration plate 2c that has been displaced upward is also displaced downward, whereby the volume of the liquid storage chamber 2a is reduced to the standby state, and the alignment film solution 12 is pushed out from the nozzle 2d, so that the droplet 20 is discharged. Discharged.

  While the inkjet head 2 is moved relative to the substrate 60 in the Y direction, droplets 20, 20, 20, 20,... Of the alignment film material are continuously dropped from each nozzle 2d. Thus, the alignment film 62 is formed on the surface of the glass substrate 60 in 12 dropping regions 26a to 26l corresponding to 12 nozzles 2d as shown in FIG. In addition, since the procedure of the dripping operation | movement to the glass substrate 60 surface of the inkjet head 2 is the same as what was demonstrated using FIGS. 8-11 mentioned above, it abbreviate | omits.

  The measurement stage 6 can suck and hold the glass substrate 60 placed on the upper surface thereof, and can move the glass substrate 60 in the XY directions with respect to the film thickness measuring device 5. In this case, as the film thickness measuring device 5, any measuring means can be used as long as the film thickness of the alignment film 62 formed on the surface of the glass substrate 60 can be measured. In the present embodiment, as an example, an optical interference type film thickness measuring device 5 is used.

  The optical interference type film thickness measuring instrument 5 irradiates the glass substrate 60 on which the alignment film 63 is formed with light inclined at a predetermined angle. By the irradiated light, reflected light reflected on the surface of the alignment film 62 and reflected light reflected on the interface between the alignment film 62 and the glass substrate 60 are generated, and by measuring interference between these two reflected lights. The thickness of the alignment film 62 is measured.

  In this case, the film thickness measuring instrument 5 moves the dropping regions 26a to 26l of the alignment film 62 formed on the glass substrate 60 along the direction (X direction) orthogonal to the dropping movement direction Y by the movement of the measurement stage 6. Then, the film thickness of the alignment film 62 is measured. In this case, as shown in FIG. 1, if the film thickness at a plurality of locations including the substantially central portion of the alignment film 62 formed on the surface of the glass substrate 60 is measured, for example, a plurality of film thicknesses measured at a plurality of locations. The accuracy of film thickness measurement can be improved by averaging the film thickness values in the measurement data. In addition, the film thickness of the alignment film 62 along the dropping movement direction (Y direction) such as when the dropping amount of the alignment film material from one of the nozzles 2d changes while the inkjet head 2 is dropping is moved. Since the change can also be detected, it becomes easy to identify a defective nozzle in which the dropping amount of the alignment film material changes during the dropping movement.

  The dropping amount adjusting unit 10 is connected to the control unit 8, and film thickness measurement data from the film thickness measuring device 5 is input via the control unit 8. The storage unit 9 stores target desired film thickness data in each of the dropping regions 26 a to 26 l of the alignment film 62.

  The storage unit 9 is connected to the dropping amount adjusting unit 10, and the dropping amount adjusting unit 10 receives the film thickness measurement data from the film thickness measuring device 5 input from the control unit 8 and the desired input input from the storage unit 9. Taking the difference from the film thickness data, the film thickness difference in each of the dropping regions 26a to 26l is calculated. Further, the amount of dripping from each nozzle 2d is increased or decreased based on the calculated film thickness difference in each of the dripping regions 26a to 26l. Such an increase / decrease adjustment of the dropping amount from each nozzle 2d is specifically performed by increasing / decreasing the drive voltage VH applied to the piezoelectric ceramic 2f provided in the inkjet head 2.

  FIG. 3 is a graph showing the relationship between the increase rate (%) of the drive voltage VH applied to the piezoelectric ceramic 2f and the increase amount (nm) of the thickness of the alignment film 62 to be formed. As shown in the figure, there is a substantially linear constant relationship between the increase rate of the drive voltage VH and the increase amount of the film thickness of the alignment film 62. Therefore, by using the relationship between the increasing rate of the driving voltage VH and the increasing amount of the alignment film 62, the amount of the droplet 20 dropped from the nozzle 2d for correcting the above-described film thickness difference is calculated. The amount of dripping from each nozzle 2d can be adjusted up or down by converting into the driving voltage VH to be dripped.

  FIG. 4 is a cross-sectional view showing the formation state of the alignment film 62 in each of the dropping regions 26a to 26l. For example, as shown in the drawing, the amount of dropping of the defective nozzle 2h at the center of the inkjet head 2 arranged first from the left is larger than the amount of dropping of the other nozzle 2d, and the inkjet head arranged third from the left. 2, the amount of dripping of the defective nozzle 2 h on the right side is smaller than the amount of dripping of the other nozzle 2 d, and the dropping region 26 b and the dropping region 26 i of the alignment film 62 corresponding to these defective nozzles 2 h and 2 h Similarly to the large film thickness portion Tb having a large film thickness with respect to the desired film thickness Ta, the small film thickness portion Tc having a small film thickness with respect to the desired film thickness Ta is provided.

  When such an alignment film 62 has a large film thickness portion Tb and a small film thickness portion Tc, the drop amount of the defective nozzles 2h and 2h used to form the alignment film 62 in those regions is adjusted to increase or decrease. To do. Specifically, when the desired film thickness Ta is, for example, 100 nm and the large film thickness portion Tb is 112 nm, the increase rate of the drive voltage VH of the nozzle 2d of the inkjet head 2 shown in FIG. By reducing the driving voltage VH to the piezoelectric ceramic 2f of the defective nozzle 2h by 5% from the relationship with the increase in film thickness, the large film thickness Tb can be brought close to the desired film thickness Ta as shown in FIG. .

  Similarly, when the desired film thickness Ta is 100 nm, for example, and the small film thickness portion Tb is 90 nm, the rate of increase in the driving voltage VH of the nozzle 2d of the inkjet head 2 shown in FIG. By increasing the drive voltage VH to the piezoelectric ceramic 2f of the defective nozzle 2h by 4% in relation to the increase in thickness, the small film thickness portion Tc can be brought close to the desired film thickness Ta as shown in FIG.

  As described above, the alignment film material is dropped on the surface of the glass substrate 60 from the nozzle 2d of the inkjet head 2 to form the alignment film 62, and the film thickness of the alignment film 62 is further changed in the dropping movement direction (Y direction) of the nozzle 2d. ), The difference between the film thickness measurement data and the desired desired film thickness is determined for each orientation film material dropping position (region) of each nozzle 2d. Calculation is performed to adjust the amount of the alignment film material dropped from each nozzle 2d. In this way, the amount of alignment film material dropped from each nozzle 2d of the inkjet head 2 is adjusted (corrected) so that the amount of alignment film material dropped 20 from the defective nozzle 2h is reduced. It is possible to prevent local formation of a portion where the thickness of the alignment film is non-uniform so that 22, 23, and 24 are adjacent to each other. As a result, streaky display unevenness 41 in the image display of the liquid crystal display panel 40 as shown in FIG. 13 is prevented.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to such Embodiment at all, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect. For example, the film thickness of the alignment film 62 formed by the inkjet head 2 may be measured after the alignment film 62 is dried, and is not limited to the above-described embodiment.

DESCRIPTION OF SYMBOLS 1 Dropping device 2 Inkjet head 2d Nozzle 2f Piezoelectric ceramics 2h Defective nozzle 3 Dropping stage 4 Dropping controller 5 Film thickness measuring device 6 Measurement stage 7 Film thickness measuring controller 8 Control unit 9 Storage unit 20 Liquid droplets 21-24 of alignment film material Film material droplet rows 26a to 26l Dropping region Ta Desired film thickness Tb of alignment film Over-thickness portion Tc Insufficient thickness portions 31, 33, 35, 37 Arrows 32, 34, 36 X indicating movement in Y direction X Arrow indicating movement in direction 40 Liquid crystal display panel 50 Glass substrate (TFT array substrate)
53 Alignment film 60 Glass substrate (CF substrate)
62 Alignment film 70 Liquid crystal P Nozzle pitch X Direction perpendicular to the dropping movement direction Y Dropping movement direction

Claims (6)

  An inkjet head is provided so as to be movable relative to a substrate for a liquid crystal display panel in a dropping movement direction, and the substrate surface from a plurality of nozzles arranged along a direction intersecting the dropping movement direction of the inkjet head An alignment film forming method for forming an alignment film by spreading of droplets of an alignment film material dropped on the film, the film thickness measuring step for measuring the film thickness of the alignment film formed on the substrate surface, and the film A dropping amount adjusting step for increasing or decreasing the dropping amount of the alignment film material from each nozzle based on the difference between the desired film thickness and the film thickness at the alignment film material dropping position of each nozzle measured by the thickness measurement step An alignment film forming method characterized by the above.   The alignment film forming method according to claim 1, wherein in the film thickness measurement step, the film thickness of the alignment film formed on the substrate surface is measured along a direction orthogonal to the dropping movement direction.   The alignment film forming method according to claim 1, wherein in the film thickness measurement step, a plurality of locations including a substantially central location of the alignment film formed on the substrate surface are measured.   An inkjet head is provided so as to be movable relative to a substrate for a liquid crystal display panel in a dropping movement direction, and the substrate surface from a plurality of nozzles arranged along a direction intersecting the dropping movement direction of the inkjet head An alignment film forming apparatus for forming an alignment film by spreading of droplets of alignment film material dropped on the film, the film thickness measuring means for measuring the film thickness of the alignment film formed on the substrate surface, and the film A dropping amount adjusting means for increasing / decreasing the dropping amount of the alignment film material from each nozzle based on the difference between the desired film thickness and the film thickness at each nozzle's orientation film material dropping position measured by the thickness measuring means; An alignment film forming apparatus.   5. The alignment film forming apparatus according to claim 4, wherein the film thickness measuring unit measures the film thickness of the alignment film formed on the substrate surface along a direction orthogonal to the dropping movement direction.   6. The alignment film forming apparatus according to claim 4, wherein the film thickness measuring unit measures a plurality of positions including a substantially central position of the alignment film formed on the substrate surface.

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