JP2008201018A - Inkjet head alignment device - Google Patents

Abstract

An apparatus for aligning an inkjet head by a mechanism independent of a coating apparatus, and capable of aligning with an inkjet head having a two-row structure.
A camera for measuring a position of a nozzle hole of an ink jet head provided in an ink jet head unit, a control means for acquiring nozzle position data based on a measurement state of the camera, and an ink jet based on the nozzle position data An inkjet head alignment apparatus comprising: a position adjusting mechanism that adjusts a position of the head; and a holding unit that adjusts a height and a position of the inkjet head unit, wherein the inkjet head has a two-row structure.
[Selection] Figure 1

Description

  The present invention relates to an alignment apparatus that performs an inkjet head positioning operation in an ink discharge apparatus used for manufacturing a color filter for a liquid crystal display or an electrode for an organic EL display, for example.

  In recent years, with the development of personal computers, the increase in size of liquid crystal televisions and the spread of mobile phones, demand for color liquid crystal displays tends to increase. However, cost reduction is indispensable for further spread, and there is an increasing demand for cost reduction of a color filter having a large cost ratio.

  Currently, (1) a dyeing method, (2) a pigment dispersion method, (3) a printing method, (4) an electrodeposition method, and (5) an ink jet method are known as methods for producing a color filter.

  (1) A dyeing method is a pattern in which a water-soluble polymer for dyeing is formed on a glass substrate, patterned into a desired shape through a photolithography process, and then immersed in a dyeing solution. This is repeated three times to obtain R, G, B color filter layers. The filter obtained by this method has a high transmittance and abundant hue, and since the technology is highly complete, it has been widely used in color solid-state image sensors (CCDs) at present, but it is inferior in light resistance due to the use of dyes. Due to the large number of manufacturing processes, the pigment dispersion method has recently been replaced for liquid crystal display elements (LCD).

  (2) The pigment dispersion method is the most mainstream color filter manufacturing method in recent years. First, a resin layer in which a pigment is dispersed is formed on a glass substrate and patterned through a photolithography process. This is repeated three times to obtain R, G, and B color filter layers. Although this method has a high degree of perfection of technology, it has a drawback in that it has many steps and high cost.

  (3) The printing method is a color filter layer in which a pigment is dispersed in a thermosetting resin and printing is repeated three times to separate R, G, and B, and then heat is applied to cure the resin. Get. This method does not require photolithography in forming the R, G, and B layers, but has a problem in terms of resolution and film thickness uniformity.

  (4) The electrodeposition method involves electrodeposition coating by applying a high voltage of about 70 V on a previously patterned transparent electrode in an electrolytic solution in which a pigment is dispersed in a water-soluble polymer to form an electrodeposition film. This is repeated three times to obtain R, G, and B color filter layers. This method has the disadvantage that it is necessary to pattern a transparent electrode in advance by photolithography and use it as an electrode for electrodeposition, and the pattern shape is limited, so that it cannot be used for TFT liquid crystal.

  In order to compensate for the above drawbacks, color filter manufacturing methods utilizing an ink jet method have been actively developed and studied (see, for example, Patent Documents 2, 3, and 6). The method using the ink jet method has an advantage that the manufacturing process is simple and the cost is low.

  A color filter manufacturing apparatus using a color filter manufacturing method using the ink jet method has a relative relationship between a recording medium and an inkjet head in which a plurality of nozzles are linearly arranged for each color of R, G, B or Y, M, and C. A recording medium feeding means that reciprocates in the main scanning direction and intermittently feeds a set amount in the sub-scanning direction, and moves the ink-jet head in the main scanning direction while transferring ink from the head to the recording medium with a pressure generator. Is pressed at a predetermined pressure, and based on the pressure, ink is ejected from the nozzles on the nozzle forming surface as ink droplets of a controlled size toward the recording medium, and a plurality of colored portions are colored simultaneously for each color.

  The ink ejection characteristics from the nozzles of the ink jet head need to be maintained constant. Therefore, in such a manufacturing apparatus, it is important to adjust the nozzle position of each inkjet head with high accuracy and to maintain the nozzle position of each inkjet head in the ejection process.

  Further, since the alignment mechanism requires a large number of axes in the X, θ, and Z directions, it cannot be made compact if a conventional fine adjustment mechanism in combination with a fine movement stage or a micrometer head is used. And the dimension of an inkjet head unit will increase, and an apparatus will enlarge as a result.

  However, when an ink jet coating apparatus is used to manufacture an optical element such as a color filter, extremely high adjustment accuracy is required (see, for example, Patent Documents 1 to 5). For this reason, it has been required to make the ink jet head unit as light and compact as possible and to improve the movement accuracy.

  However, it takes a very long time to adjust the nozzle position of the inkjet head with high accuracy. In particular, when ejecting onto a large recording medium, if the ejection width of the inkjet head is narrow, it will reciprocate over the coating medium many times, so it is necessary to arrange several inkjet heads in order to shorten the tact time. Yes, all inkjet heads such as R, G, and B must be adjusted with high accuracy.

  And if it is going to adjust with high precision on a coating device, since it will take so much as an inkjet head in adjustment time, it will lead to the fall of an operation rate. Therefore, an apparatus is used in which only the inkjet head unit is removed from the coating machine and the inkjet head can be aligned by external setup.

In addition, there are cases where the structure of the inkjet head is different, such as one having a single nozzle row and two nozzle rows. When two-row nozzles are used, it is more compact than when two single-row nozzles are used. However, in the case of one row, it is only necessary to align the nozzle rows. However, in the case of two rows, the two nozzle rows cannot be completely parallel because of the processing structure. In that case, even if one column is aligned with the ideal position, the other column is not aligned with the ideal position.
Japanese Patent Laid-Open No. 9-101212 Japanese Patent Laid-Open No. 9-277571 JP-A-10-332924 Japanese Patent Laid-Open No. 11-2711 Japanese Patent Laid-Open No. 11-64626 JP 2001-343513 A

  Accordingly, an object of the present invention is to provide an alignment apparatus that performs alignment of an inkjet head by a mechanism independent of a coating apparatus, and that can align with an inkjet head having a two-row structure.

  In order to achieve the above object in the present invention, first, in the invention of claim 1, a camera for measuring a position of a nozzle hole of an ink jet head provided in an ink jet head unit, and nozzle position data based on a measurement state of the camera. Control means for obtaining the position of the ink jet head, a position adjusting mechanism for adjusting the position of the ink jet head based on the nozzle position data, and a holding means for adjusting the height and position of the ink jet head unit. This is an inkjet head alignment device characterized by a column structure.

  According to a second aspect of the invention, there is provided an inkjet head alignment apparatus according to the first aspect, wherein a plurality of the cameras are provided.

  According to a third aspect of the present invention, the position adjustment mechanism acquires the position coordinates in the nozzle row direction, height direction, and horizontal rotation direction of an inkjet head having a two-row structure, and adjusts the position coordinately. An inkjet head alignment apparatus according to claim 1.

  According to a fourth aspect of the invention, in the ink jet head alignment apparatus according to the first aspect, the position adjusting mechanism adjusts the position of the ink jet head with reference to an alignment mark provided on the ink jet head unit. Is.

  According to a fifth aspect of the present invention, there is provided the inkjet head alignment apparatus according to the first aspect, wherein the nozzle position data is sent to the coating apparatus to be utilized in the coating process.

  According to a sixth aspect of the present invention, the nozzle position coordinate feedback of the ink jet head is received from the coating apparatus and automatically adjusted to a designated coordinate by using the position adjusting mechanism. This is a head alignment device.

  By the adjustment method by the alignment device of the inkjet head of the present invention, the mechanism independent of the coating apparatus can be aligned with the inkjet head of the two-row head so as to realize a highly accurate nozzle arrangement, As a result, the coating accuracy of the coating body can be improved. In addition, it is possible to use an ink jet head that cannot be used with low accuracy by a normal adjustment method.

  In the embodiment of the present invention, in the color filter manufacturing process by the ink jet method, the fine adjustment mechanism is used to adjust the position of each ink jet head in the nozzle row direction, the rotation direction, the horizontal direction, and the height direction. The present invention provides an alignment apparatus and an adjustment method that enable a simple inkjet head arrangement and prevent the operating rate of the coating apparatus from being lowered.

  This alignment apparatus is provided independently of the coating apparatus shown in FIG. 2, and has a configuration in which an inkjet head unit adjusted in advance by this alignment apparatus is installed in the coating apparatus to perform a coating operation. However, it is possible to transfer the data obtained by this alignment apparatus to the coating apparatus and use it for positioning such as the coating timing.

  Specifically, an alignment mark is attached to the ink jet head unit. The alignment mark is detected, the coordinates of the nozzle holes (nozzle position data) of each head are detected, and the head is adjusted using a fine adjustment mechanism. Align and hold the posture of each inkjet head. Then, position information (nozzle position data) from the alignment mark can be sent to the coating apparatus so that it can be utilized, and the coating setup time can be greatly reduced.

  The fine adjustment mechanism also arranges the nozzle rows in parallel in the direction perpendicular to the scanning direction, aligns the head ends so that they move straight in the scanning direction, makes the height horizontal, and places all the heads on the coating stage. Make a certain amount the same height. This can be adjusted not only on the alignment apparatus but also on the coating apparatus by communication from the controller. For such a fine adjustment mechanism, various conventionally known structures can be employed.

  In addition, the manufacturing method of the color filter by the inkjet method basically applies ink onto a transparent substrate such as a glass substrate to form a colored portion. The method includes a method of curing and coloring the ink itself, a method of forming a receiving layer made of a resin having ink absorptivity on a transparent substrate, and applying the ink to the receiving layer for coloring, or on a transparent substrate. The method is roughly classified into a method of applying ink to a bank having black ink repellency and coloring, and the present invention is preferably applied to any method.

  First, prior to description of an inkjet alignment apparatus according to an embodiment of the present invention, a coating apparatus that can be used in combination with this alignment apparatus will be described.

  FIG. 2 is an external view showing an outline of an inkjet color filter manufacturing apparatus (coating apparatus).

  In FIG. 2, an ink jet head unit 1 has a plurality of ink jet heads arranged in parallel, and applies ink to a transparent substrate 2 arranged to face each ink jet head. The maintenance device 3 is for maintaining the ejection stability of the inkjet head.

  The main scanning direction moving device 4 and the sub-scanning direction moving device 5 constitute an XY stage drive system. The main scanning direction moving device 4 moves a Y-direction movable portion (substrate stage) that reciprocates during ink application. On the other hand, the sub-scanning direction moving device 5 moves the X-direction movable portion that is intermittently sent to apply the necessary width to the transparent substrate 2 during ink application.

  In such a color filter manufacturing apparatus, after the inkjet head unit 1 is moved relative to the transparent substrate 2 in the main scanning direction in advance, the ink liquid is ejected from the head onto the transparent substrate 2 and applied, and ejected a predetermined number of times. After performing the above, the maintenance device 3 is used to stabilize the discharge characteristics.

  After the ejection stability of the inkjet head is improved by the maintenance device 3, the process proceeds to the color filter drawing process.

  First, the inkjet unit 1 is moved to the end of the transparent substrate 2 by the sub-scanning direction moving device 5. The main scanning direction moving device 4 performs main scanning a predetermined number of times n (n is a natural number) to apply ink onto the transparent substrate 2.

  The relationship between the stage and the ink ejection timing during the drawing operation is that the substrate stage moves in the main scanning direction, and ink is ejected from the nozzles of the inkjet head in synchronization with the position in the main scanning direction. Then, after scanning a predetermined number of times, the sub-scanning moving device 5 moves to the end of the uncoated portion of the transparent substrate 2 and moves in the main scanning direction to apply again a predetermined number of times.

  Next, the color filter obtained by the above process will be described.

  As described above, the method for producing a color filter by the ink jet method includes a method of curing and coloring the ink itself, a receiving layer made of a resin having ink absorbability, etc. formed on a transparent substrate. There are a method of coloring by applying ink to the surface, and a method of coloring by coloring ink on a bank having a black matrix ink repellency on a transparent substrate.

  FIG. 3 is a schematic view showing an example during coating of a color filter.

  The black matrix 6 includes ink repellency formed on the transparent substrate 2 and serves as a barrier for curing the ink. Further, 7 indicates a Red ink droplet, 8 indicates a Green ink droplet, and 9 indicates a Blue ink droplet. In this example, in order to form colored portions of three colors R, G, and B, three ink jet heads must be used, and ink droplets must be applied to the respective openings of the black matrix. Even when ink is applied to a receiving layer made of an ink-absorbing resin or the like, it must be ejected to a predetermined location in order to prevent color mixing and misdirection of the ejection position.

  From the pixel size of the color filter, the allowable value of the misregistration error in the main scanning direction is calculated as an example. The opening of the black matrix 6 is about 120 μm, the ink droplet diameter is about 100 μm, the stage movement error, and the coating variation. In consideration of the above, the tolerance of the inkjet head is about ± 5 μm. Therefore, very high accuracy is required for alignment of the inkjet head and the transparent substrate in the apparatus. The color filter pixel size varies to some extent depending on the black matrix pattern, and the wider the opening, the less the required accuracy for painting. In addition, the ink droplets to be applied have different ink droplet diameters depending on the type of ink and the amount of ink dropped.

  Next, an inkjet head alignment apparatus according to an embodiment of the present invention will be described.

  FIG. 1 is an external view showing the configuration of an inkjet head alignment apparatus according to an embodiment of the present invention.

  In the inkjet head unit 1, a plurality of inkjet heads 10 to be aligned are arranged in parallel and supported by an XY stage 11 of an alignment apparatus. On the nozzle formation surface of the inkjet head 10, a nozzle row formed by a plurality of nozzles is provided.

  The ink-jet head unit 1 includes a holder and a plurality of ink-jet heads 10 provided on the holder, and each ink-jet head 10 has two directions perpendicular to the holder on the horizontal plane and a vertical direction via a support mechanism. It is supported finely adjustable and finely adjustable around a vertical axis. In addition, conventionally well-known various structures are employable for such a support mechanism.

  Two nozzle hole observation cameras 12 are installed on the stage 11 of the alignment apparatus. In addition, since there are two nozzle hole observation cameras 12, it is possible to simultaneously observe two nozzle hole positions of the inkjet head. That is, it is very advantageous to adjust the X direction and the Y direction of the inkjet head by observing the two nozzle holes.

  The X-direction slider 13 and the Y-direction slider 14 move the camera when observing the nozzle surface of the inkjet head 10. The anti-seismic table 15 is provided in order to remove the vibration because the precision alignment is affected if the vibration is received during the precision alignment.

  The head unit holder 16 receives the inkjet head unit 1, and rotates in the horizontal direction so that the moving directions of the Y-direction slider 14 and the X-direction slider 13 are aligned with the main scanning direction and the sub-scanning direction of the coating apparatus, respectively. It has become.

  Then, the alignment mark attached to the inkjet head unit 1 is read and adjusted so that the main scanning direction of the coating apparatus and the Y-direction slider 14 are parallel, and the nozzle row of the inkjet head is parallel to the X-direction slider 13. Align the inkjet heads. The nozzle hole observation display 17 displays images from the two cameras 12, and shows a reticle or the like on the screen and is used to align the nozzle holes.

  The nozzle row structure of the inkjet head includes a one-row structure and a two-row structure. FIG. 4 is an external view of an ink jet head having a two-row structure. In the inkjet head unit 1, since the number of inkjet heads 10 is halved when a two-row structured head is adjusted rather than adjusting a one-row structured head, the mounted adjustment mechanism is also halved. Can be greatly reduced. When producing a color filter with a large substrate, since the number of inkjet heads is large, it is advantageous to use a two-row inkjet head.

  In addition, by adopting a two-row inkjet head, the number of ink supply ports is two for one inkjet head. Since the two ink supply ports are close to each other, as shown in FIG. 4, by using a Y-shaped pipe ink tube 21, the number of pipes from the ink distributor is reduced by half.

  By registering nozzle holes as mark positions for image processing in an inkjet head having a two-row structure, for example, it is possible to obtain the nozzle hole position accuracy of the inkjet head by acquiring the coordinates of the nozzle ends. This nozzle hole is adjusted using an adjustment mechanism to the ideal coordinates from the alignment mark attached to the inkjet head unit to be adjusted.

  When the nozzle row structure of the inkjet head is a double row structure, even if the nozzle row on one side (referred to as row A) is aligned in parallel with the X-direction slider 13, the other nozzle row (referred to as row B) will remain in the X direction. The slider 13 may not be parallel. This is due to the manufacturing accuracy of the head, and it is difficult to create a head satisfying the parallel tolerance of 5 μm between the A row and the B row. There is a problem that the cost for the inkjet head is increased.

  Therefore, as shown in FIG. 5, for example, as shown in FIG. 5, the adjustment is performed by an allocation method that allows the use of an inkjet head having a nozzle hole position shift of 5 μm or more, which can be used by adjustment. That is, the nozzles at both ends of the row A head are observed and adjusted by the alignment device, and after parallelism in the X direction, the nozzles at both ends of the row B head are observed and measured. At that time, if the parallelism in the X direction falls within the allowable accuracy of less than 5 μm, the process proceeds to the next head to be adjusted. If the difference in the Y coordinate of the end nozzle of the B row head is less than twice the allowable error (in this case, 5 μm <Y ≦ 10 μm), half of the difference in the Y coordinate is calculated and fine adjustment is performed accordingly. By allocating in this way, the A column head error 0 and the B column head error 10 μm become the A column head error −5 μm and the B column head error 5 μm, and the coating accuracy can be maintained.

  As a result, the Y-direction error of the inkjet head may be 0 ≦ Y ≦ twice the allowable accuracy. In addition, the same adjustment method can be applied to the X direction. The distance between the nozzle at the end of the A head and the nozzle at the end of the B head is fixed, and if the pitch is different, there is a risk of riding on the BM in the X direction. Therefore, by performing the same allocation adjustment, the X direction can be used up to twice the allowable accuracy. Therefore, it is possible to assign accuracy errors of the A column and the B column for all the axes to be adjusted.

  The alignment control panel 18 is used for switching and adjusting the rotation signal of the fine adjustment mechanism motor. The adjustment controller 19 rotates the motor of the fine adjustment mechanism and is used for adjusting the position of the inkjet head. The ink jet heads to be adjusted in order on the alignment control panel 18 are switched, and the position accuracy is adjusted using the adjustment controller 19 each time. The motor switching BOX 20 switches the drive motor and is controlled by the alignment control panel 18. The drive motor is installed on each inkjet head for the adjustment axis.

  The holding means of the ink jet head unit 1 supports, for example, the ink jet head unit frame as in the coating apparatus, and even if the ink jet head unit 1 is elastically deformed by its own weight, the same deformation occurs on the alignment device. Therefore, the alignment is not affected.

  That is, the holding means of the alignment apparatus includes the head unit holder 16 and adjusts the height and position of the inkjet head unit 1 and is compatible with the holding means on which the inkjet head unit 1 is mounted in the coating apparatus. Is.

  If it is necessary to adjust the position of the inkjet head when the displacement of the discharge is found during coating, an adjustment controller 19 is connected to the motor switching BOX 20 and an inverted microscope attached to the stage of the coating machine body. It is possible to adjust a predetermined inkjet head while checking the nozzle of the inkjet head. Therefore, when adjusting a small number of inkjet heads, it is not necessary to carry the inkjet head unit to the alignment device.

  In addition, by sending the nozzle hole position data of the inkjet head arranged at a predetermined position after alignment to the coating device, the Y coordinate of the nozzle end of each inkjet head is reflected in the coating timing, and at the time of coating It is possible to shorten the setup time.

  By producing two or more inkjet head units 1, one is used for coating, the other is adjusted, and when it is time to replace the coated inkjet head, the adjusted inkjet head By replacing the unit, production will not stop.

1 is an external view showing a configuration of an alignment apparatus for an inkjet head according to an embodiment of the present invention. It is an external view which shows an example of a coating device. It is a schematic diagram which shows the example during application of a color filter. It is an external view of a two-row structure inkjet head. It is explanatory drawing of the allocation method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inkjet head unit 2 ... Transparent substrate 3 ... Maintenance apparatus 4 ... Main scanning direction moving apparatus 5 ... Sub-scanning direction moving apparatus 6 ... Black matrix 7 ... Red ink droplet 8 ... Green ink droplet 9 ... Blue ink droplet 10 ... Inkjet head DESCRIPTION OF SYMBOLS 11 ... Stage 12 ... Nozzle hole observation camera 13 ... X direction slider 14 ... Y direction slider 15 ... Isolation table 16 ... Head unit holder 17 ... Nozzle hole observation display 18 ... Alignment control panel 19 ... Adjustment controller 20 ... Motor switching BOX
21 ... Y-pipe ink tube

Claims (6)

  A camera that measures the position of a nozzle hole of an inkjet head provided in the inkjet head unit, a control unit that acquires nozzle position data based on the measurement state of the camera, and a position adjustment of the inkjet head based on the nozzle position data An inkjet head alignment apparatus, comprising: a position adjusting mechanism that performs a positioning operation, and a holding unit that adjusts a height and a position of the inkjet head unit, wherein the inkjet head has a two-row structure.   The inkjet head alignment apparatus according to claim 1, comprising a plurality of the cameras.   2. The inkjet head according to claim 1, wherein the position adjustment mechanism acquires and coordinates the position coordinates of the nozzle row direction, the height direction, and the horizontal rotation direction of the inkjet head having a two-row structure. Alignment device.   The inkjet head alignment apparatus according to claim 1, wherein the position adjustment mechanism adjusts the position of the inkjet head based on an alignment mark provided in the inkjet head unit.   The inkjet head alignment apparatus according to claim 1, wherein the nozzle position data is sent to a coating apparatus to be used in a coating process.   2. The inkjet head alignment apparatus according to claim 1, wherein the nozzle position coordinate feedback of the inkjet head is received from the coating apparatus and automatically adjusted to a designated coordinate using the position adjustment mechanism.