JP2010110700A - Inkjet coater, and parallel degree adjustment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet coater which allows the measurement of measuring a distance between a nozzle surface and a parallel degree adjustment plate at non-contact, and allows the easy performance of the adjustment of an angle of the nozzle surface and the parallel degree adjustment plate. <P>SOLUTION: A symbol 1 is the inkjet coater for depositing a delivery liquid at a desired position of a substrate 16 arranged on a substrate stage 12. The inkjet head 30 has first-third distance sensors 33<SB>1</SB>-33<SB>3</SB>and the parallel degree adjustment apparatus 25, and the distance of the nozzle surface and the nozzle surface adjustment plate 20 arranged on the substrate stage 12 is measured by the first-third distance sensors 33<SB>1</SB>-33<SB>3</SB>. Based on the measurement result, the angle of the nozzle surface relative to the nozzle surface adjustment plate 20 is adjusted by a nozzle surface adjustment mechanism 40 possessed by the parallel degree adjustment apparatus 25, and moves the inkjet head 30 to a desired position on the substrate 16 while maintaining the angle. The substrate 16 can be coated with a coating liquid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a nozzle surface adjusting means for measuring a nozzle surface and an adjustment plate of an inkjet head in a non-contact manner, and adjusting and maintaining a predetermined interval from the information.

  Reference numeral 100 in FIG. 5 is a conventional inkjet coating apparatus. The conventional method for measuring the distance between the nozzle plate 136 and the substrate 116 is described in the following document, for example.

The print head 126 has a head body 135 and a nozzle plate 136. The print head 126 is connected to the support unit 105 via the mounting system actuator 107. Distance sensors 133 ₁ and 133 ₂ for measuring the height from the substrate 116 to the nozzle plate 136 are also connected to the support portion 105. The support portion 105 is connected to the printing bridge 118 via the main actuator 106.
Adjustment of the distance between the nozzle plate 136 and the substrate 116 measured by the distance sensors 133 ₁ and 133 ₂ is performed by the mounting system actuator 107.

According to the invention of the following document, since the nozzle plate 136 can be adjusted only in the height direction of the nozzle plate 136, it cannot be corrected when the nozzle plate 136 is inclined in the depth direction.
JP 2007-144497 A

  The nozzle plate 136 is provided with a plurality of ejection holes 139, and the droplets ejected from the nozzle plate 136 are greatly related to the landing position accuracy depending on the degree of inclination between the nozzle plate 136 and the substrate 116. Here, the thickness of the nozzle plate 136 is constant.

As shown in FIG. 6A, the nozzle plate 136 and the substrate 116 are parallel, the variation in the discharge angle of the print head 126 is θ ₁ , and the distance between the nozzle plate 136 and the substrate 116 is L ₁ . When the nozzle plate 136 is inclined at an angle of θ ₂ with respect to the substrate 116 as shown in b), if the distance between the center of the nozzle plate 136 and the substrate 116 is L ₁ and the displacement of the landing position is L ₃ , L ₃ is According to the following formula (1).

L ₃ = L ₁ × tan (θ ₁ + θ ₂ ) ...... Formula (1)
At this time, the deviation L ₅ of the landing position from the ejection hole 139 where the distance from the central axis 108b of the print head 126 is at the position of L ₄ follows the following formula (2).

L ₅ = {L ₁ + (L ₄ × sin θ ₂ )} × tan (θ ₁ + θ ₂ ) (2)
For example, when θ ₁ = 1 [°], L ₁ = 0.5 [mm], and θ ₂ = 0.5 [°], L ₃ = 0.013 [mm] from the above equation (1). The landing position shifts.
Further, the deviation of the landing position of the droplets ejected from the position away from the central axis 108b by L ₄ = 20 [mm] is L ₅ = 0.0176 [mm] from the above equation (2).

  In the above example, only the inclination in the horizontal direction is considered. However, the inclination may be in the depth direction. If the parallelism between the substrate 116 and the nozzle plate 136 is insufficient, the application position accuracy deteriorates.

In order to solve the above problems, the present invention includes a substrate stage on which a substrate is disposed, and an inkjet head configured to be relatively movable with respect to the substrate stage, and a nozzle provided on a nozzle surface of the inkjet head. An ejection device configured to eject ejection liquid from a hole to the substrate, wherein a nozzle surface adjustment plate is disposed on the substrate stage, and the inkjet head is disposed on the nozzle surface. First to third sensors whose positions are fixed and capable of emitting detection signals; measuring devices measured by the first to third sensors; and an angle of the nozzle surface to the nozzle surface adjustment plate is changed. A measurement device for measuring a measurement signal generated as a result of the detection signal being emitted from the first to third sensors to the nozzle surface adjustment plate. An ink jet coating apparatus that obtains a distance between three points on the nozzle surface and the nozzle surface adjustment plate and makes the nozzle surface and the nozzle surface adjustment plate parallel to each other by the nozzle surface adjustment mechanism from a measurement result. .
In the present invention, the inkjet head includes a vertical movement device that moves the inkjet head up and down, and the measurement device measures a distance between the nozzle surface and the nozzle surface adjustment plate, and from the measurement result, It is an inkjet coating device which makes a predetermined distance between the nozzle surface and the nozzle surface adjustment plate by a vertical movement device.
In the present invention, a coil is provided in each of the first to third sensors, a metal plate is used for the nozzle surface adjustment plate, an AC voltage is applied to the first to third coils, In the ink jet coating apparatus, the formed magnetic field lines are used as the detection signal, and the alternating current flowing through the first to third coils is used as the measurement signal.
According to the present invention, first to third ultrasonic emission devices and first to third ultrasonic detection devices are provided in the first to third sensors, respectively. A reflected wave ultrasonic wave plate is used, the reflected ultrasonic wave emitted from the ultrasonic wave emitting device is used as the detection signal, reflected by the nozzle surface adjusting plate, and detected by the first to third ultrasonic wave detecting devices. An inkjet coating apparatus using sound waves as the measurement signal.
In the first to third sensors of the present invention, first to third light emitting devices and first to third light receiving devices are provided, respectively, and a nozzle plate is used as the nozzle surface adjustment plate. The inkjet coating apparatus uses the emitted light emitted from the light emitting device as the detection signal, the reflected light reflected by the nozzle surface adjustment plate and detected by the first to third light receiving devices as the measurement signal.
The present invention includes a substrate stage on which a substrate is arranged, and an inkjet head configured to be relatively movable with respect to the substrate stage, and ejects the substrate from nozzle holes provided in a nozzle surface of the inkjet head. An ejection device configured to eject liquid, wherein the nozzle of the inkjet head is formed on a nozzle surface adjustment plate made of metal, and the position of the substrate stage is fixed with respect to the surface of the substrate stage The first to third coils that can emit detection signals, the measuring devices measured by the first to third coils, and the nozzle surface adjustment that changes the angle of the metal plate surface with respect to the substrate stage surface An alternating current that flows from the first to third coils to the nozzle surface adjustment plate as a detection signal and flows to the first to third coils. The flow is measured as a measurement signal, and the measurement device calculates a distance between three points on the nozzle surface adjustment plate and the substrate stage, and the nozzle surface adjustment mechanism calculates the nozzle surface from the calculated distance. An inkjet coating apparatus in which a plate surface and the substrate stage surface are made parallel to each other.

  It is possible to measure the distance between the adjustment plate and the nozzle surface with three or more distance sensors included in the inkjet head and adjust the angle between the adjustment plate and the nozzle surface with the nozzle surface adjustment mechanism.

Reference numeral 1 in FIG. 1 is an example of the ink jet coating apparatus of the present invention.
The inkjet coating apparatus 1 includes a pedestal 10, a substrate stage 12, a gantry 13, and an inkjet head 30. The pedestal 10 has a plate shape and is disposed horizontally. On the surface of the pedestal 10, two elongated rails 11a and 11b are disposed in parallel.

  Each of the two rails 11 a and 11 b is provided with a main substrate stage moving mechanism (not shown), and a sub-moving mechanism (not shown) is provided on the back surface of the plate-like substrate stage 12.

The main substrate stage moving mechanism and the sub substrate stage moving mechanism are engaged, and the sub substrate stage moving mechanism is configured to be movable along the main substrate stage moving mechanism.
The substrate stage 12 is disposed on the rails 11a and 11b, and is configured to be movable in one plane on the rails 11a and 11b by the main substrate stage moving mechanism.

The gantry 13 has struts 18a and 18b and a printing bridge 18c. The columns 18a and 18b are erected on the surface of the base 10 outside the rails 11a and 11b.
The printing bridge 18c is disposed at a position above the height of the range in which the substrate stage 12 moves, and is fixed by upright columns 18a and 18b.

The substrate stage 12 is configured to pass a position between the base 10 and the printing bridge 18c.
An elongated head moving device 15 is disposed along the longitudinal direction of the printing bridge 18 c, and the inkjet head 30 is attached to the head moving device 15.

The ink jet head 30 is configured to be reciprocally moved along the longitudinal direction of the printing bridge 18 c by the head moving device 15.
A coating solution storage tank 19 is disposed outside the inkjet coating apparatus 1, and the coating solution storage tank 19 and the inkjet head 30 are connected, and the coating solution is supplied from the coating solution storage tank 19 to the inkjet head 30.

  A nozzle plate 36 is provided on the bottom surface of the inkjet head 30. As will be described later, a plurality of discharge holes 39 are formed in the nozzle plate 36, and the coating liquid supplied from the coating liquid storage tank 19 to the inkjet head 30 is selected by a control device (not shown). It can be discharged from.

  The nozzle plate 36 and the substrate stage 12 are adjusted in parallel and separated by a set distance by a nozzle surface adjustment method to be described later, the substrate is placed on the substrate stage 12, and the main substrate stage moving mechanism and the head are arranged. When the moving device 15 is operated, as shown in FIG. 2, the inkjet head 30 can be moved to a desired position on the substrate, and the coating liquid can be landed on the desired position on the substrate 16 from the ejection holes 39.

  Further, in a state where the nozzle plate 36 and the surface of the substrate stage 12 are made parallel, the ink jet head 30 can be moved by the head moving device 15 while maintaining the parallel state, and the coating liquid can be discharged onto the surface of the substrate 16. I can do it.

<Configuration of inkjet head>
3A is a plan view of the inkjet head 30, FIG. 3B is a side view of the inkjet head 30, and FIG. 3C is a perspective view of the inkjet head 30.
The ink jet head 30 includes a parallelism adjusting device 25 and a head main body 26.

  The parallelism adjusting device 25 includes a head fixing plate 32, a bearing holding member 34, and a nozzle surface adjusting mechanism 40, and the head fixing plate 32 is supported by the head moving device 15. The head body 26 and the bearing holding member 34 are connected via a nozzle surface adjustment mechanism 40.

  The head main body 26 includes a tank portion 35 and a nozzle plate 36 fixed to the bottom surface of the tank portion 35. The plurality of nozzle holes described above are formed in the nozzle plate 36. Reference numeral 39 indicates a nozzle hole.

The bearing holding member 34 incorporates a nozzle surface adjustment mechanism 40, and here, for example, includes a spherical bearing 37 (Heheist: SRJ series) and a head body fixing portion 38. The shape of the spherical bearing 37 is a sphere.
A plane parallel to the substrate stage 12 is defined as an xy plane, and a direction perpendicular to the xy plane is defined as a z direction.

  The nozzle surface adjustment mechanism 40 has a drive system and a control device (not shown). A control device is connected to the drive system and the head main body fixing portion 38, and the spherical bearing 37 causes the head main body fixing portion 38 to be centered on the spherical bearing 37 in the xz plane and the yz plane according to a signal from the control device. It can be rotated around a point.

The spherical bearing 37 and the head main body 26 are connected via a head main body fixing portion 38, and when the spherical bearing 37 is moved, the nozzle plate 36 can be rotated and moved in the xz plane and the yz plane. .
Further, when a signal is sent from the control device to the head main body fixing unit 38, the nozzle plate 36 is maintained in an inclined state and can be fixed.

  The head fixing plate 32 is provided with a vertical movement device 29, and a bearing holding member 34 connected to the head body 26 is supported by the vertical movement device 29 and can move up and down while maintaining the inclination of the nozzle plate 36. It is configured to be able to.

  The head fixing plate 32 is supported by the head moving device 15 and can reciprocate along the longitudinal direction of the printing bridge 18c. The bearing holding member 34 connected to the head main body 26 is supported by the vertical movement device 29, and is movable along the longitudinal direction of the printing bridge 18c while maintaining the inclination of the nozzle plate 36.

<Nozzle surface adjustment method>
The inkjet head 30 has first to third distance sensors 33 _{1 to} 33 ₃ .

The first to third distance sensors 33 _{1 to} 33 ₃ are fixed to the nozzle plate 36.
The nozzle plate 36 has a constant thickness and is formed wider than the bottom surface of the tank portion 35.

Here, the first to third distance sensors 33 _{1 to} 33 ₃ are arranged in the vicinity of the outer periphery of the nozzle plate 36 that protrudes from the tank portion 35. The first to third distance sensors 33 _{1 to} 33 ₃ are not arranged on a straight line, form a triangle, and are parallel to the nozzle plate 36. The back surface of the nozzle plate 36 is referred to as a nozzle surface.

FIG. 4A is a view showing the internal structure of the first to third distance sensors 33 _{1 to} 33 ₃ arranged on the nozzle plate 36.
FIG. 4B is a view of the nozzle surface viewed from a position directly below the nozzle plate 36.

In the first example of the present invention, the first to third distance sensors 33 _{1 to} 33 ₃ are configured by first to third coils 28 _{1 to} 28 ₃ , and the first to third coils 28 _{1 to} 28 3 are included. _Three central axes are arranged perpendicular to the nozzle plate 36. The first to third AC voltage power supplies 41 _{1 to} 41 ₃ and the first to third measuring devices 42 _{1 to} 42 ₃ are connected to the first to third coils 28 _{1 to} 28 ₃ .

On the outer periphery of the substrate stage 12 other than the region where the substrate 16 is disposed on the substrate stage 12, a nozzle surface adjustment plate 20 is disposed in parallel with the substrate stage 12.
The nozzle surface adjustment plate 20 is made of metal and has a constant thickness. The surface area of the nozzle surface adjustment plate 20 is equal to or greater than the surface area of the nozzle plate 36.

Before printing on the substrate 16, the main substrate stage moving mechanism and the head moving device 15 are operated to move the nozzle plate 36 to a position directly above the nozzle surface adjustment plate 20 and to make it stationary.
The vertical movement device 29 is operated to bring the nozzle surface adjustment plate 20 and the nozzle plate 36 closer to each other.

When an alternating current is supplied by applying a voltage of a predetermined frequency to the AC voltage source 41 ₁ to 41 ₃ by energizing the first to third coil 28 _{1-28 3,} magnetic field lines are formed as a detection signal, a first When reaching the nozzle surface adjusting plate 20 located just below the third coils 28 _{1 to} 28 ₃ , eddy currents are generated at the three locations.

An alternating current flowing through each coil is measured as a measurement signal, and each distance between the nozzle surface adjustment plate 20 and the lower ends of the first to third distance sensors 33 _{1 to} 33 ₃ disposed on the nozzle plate 36 is determined. If different, the amplitude widths of the alternating currents flowing through the first to third coils 28 _{1 to} 28 ₃ are obtained by the measuring devices 42 _{1 to} 42 ₃ , respectively, and the phase difference between the alternating current and the voltage is different from each other. Different values are obtained. When the distances between the nozzle surface adjustment plate 20 and the lower ends of the first to third distance sensors 33 _{1 to} 33 ₃ arranged on the nozzle plate 36 are equal, the first to third coils 28 ₁ to 28 ₁ to amplitude width of the AC current flowing to 28 ₃ are equal, the phase difference between the alternating current and voltage equal is configured to obtain.

First to the amplitude width of the third coil 28 _1-28 flowing through the ₃ AC current, the phase difference between the alternating current and voltage, the first to third lower end of the distance sensor 33 _to 333 on the nozzle plate 36 And the nozzle surface adjustment plate 20 can be measured in order of perspective.

In the direction in which the difference between the distance from the first to third distance the lower end of the sensor 33 _to 333 is reduced, by adjusting the inclination of the nozzle plate 36 in the xz plane and the yz plane, adjustment plate nozzle plate 36 to Can be parallel.

While changing the distance between the nozzle surface adjustment plate 20 and the nozzle plate 36, in the case of measuring the phase difference between the oscillation amplitude and the voltage of the alternating current flowing in the first to third coil 28 _{1-28 3,} first to At predetermined measurement points in the _three distance sensors 33 _{1 to} 33 ₃ , the distance between the nozzle surface adjustment plate 20 and the measurement point is substantially proportional to the measured amplitude width, and is based on the phase difference between the alternating current and the voltage. It is approximately inversely proportional.

A predetermined reference position from the nozzle surface adjustment plate 20 and each measurement point are matched with each other, and the amplitude width of the alternating current and the phase difference between the alternating current and the voltage are measured in advance. Further, the distance between the nozzle surface adjustment plate 20 and the reference position and the distance between the lower ends of the first to third distance sensors 33 _{1 to} 33 ₃ and the measurement point are measured.

If the distance between the nozzle face adjusting plate 20 of each measurement point is not the reference position, the amplitude width of the alternating current and the alternating current and voltage flowing through the respective measuring points of the first to third distance sensor 33 _to 333 The nozzle surface adjusting plate 20 is measured based on the distance between the nozzle surface adjusting plate 20 measured in advance and the reference position, the amplitude width of the alternating current at the reference position, and the phase difference between the alternating current and the voltage. The distance between each measurement point can be determined.

Further, when the distance between the lower ends of the first to third distance sensors 33 _{1 to} 33 ₃ and each measurement point is subtracted from the distance between the nozzle surface adjustment plate 20 and each measurement point, the nozzle surface adjustment plate 20 and each distance between the first to third lower end of the distance sensor 33 _to 333 is obtained.

When the angle between the nozzle plate 36 and the xz plane is θ _xz , and the angle between the nozzle plate 36 and the yz plane is θ _yz , the nozzle surface adjustment plate 20 and the first to third distance sensors 33 _{1 to} 33 _{3 are} lower ends. the distance between, it is possible to determine the theta _xz and theta _yz from each distance between the first to third distance sensor 33 _to 333 measured in advance, by moving the spherical bearing 37, the nozzle plate 36 can be tilted by θ _xz and θ _yz to a predetermined angle. When the nozzle surface adjustment plate 20 and the nozzle plate 36 are made parallel, the nozzle plate 36 is made parallel to the nozzle surface adjustment plate 20 by moving the spherical bearing 37 and setting both θ _xz and θ _yz to zero. Can do.

  After adjusting the nozzle plate 36 in parallel with the nozzle surface adjustment plate 20, the vertical movement device 29 is operated, and the nozzle plate 36 is separated from the nozzle surface adjustment plate 20 by a set distance in a parallel state. .

  The substrate 16 is disposed on the substrate stage 12 in parallel to the substrate stage 12, the main substrate stage moving mechanism and the head moving device 15 are operated, and the nozzle plate 36 is parallel to the nozzle surface adjustment plate 20. When the inkjet head 30 is moved to a desired position on the substrate, the coating liquid can be discharged onto the surface of the substrate 16 with the nozzle plate 36 parallel to the substrate 16.

  Here, the substrate 16 on the substrate stage 12 is disposed in order to adjust the nozzle plate 36 with respect to the nozzle surface adjustment plate 20 with the printing substrate 16 placed on the substrate stage 12. However, before the printing substrate 16 is placed on the substrate stage 12, the measurement substrate 16 made of metal is placed on the substrate stage 12, and the measurement substrate 16 is placed on the measurement substrate 16. It is also possible to adjust the inclination of the nozzle plate 36, take out the measurement substrate 16 after the adjustment, place the printing substrate 16 on the substrate stage 12, and perform printing.

There may be three or more distance sensors, and the first to third distance sensors 33 _{1 to} 33 ₃ made of coils are arranged on the substrate stage 12, and the nozzle plate 36 or the nozzle plate 36 made of metal is used. An inclination of the nozzle plate 36 may be adjusted by arranging a metal plate on the top, measuring the distance between the first to third distance sensors 33 _{1 to} 33 ₃ and the nozzle plate 36.

Above, as a first example, the distance was measured by the combination of the first to third distance sensors 33 _{1 to} 33 ₃ composed of the first to _third coils 28 _{1 to} 28 ₃ and the nozzle surface adjustment plate 20 composed of metal. but the present invention is not limited to this arrangement as the second example, a sensor for emitting ultrasonic waves into a position in which the first to third coil 28 _{1-28 3} has been arranged in the first embodiment And a reflecting plate is arrange | positioned in the position where the nozzle surface adjustment board 20 was arrange | positioned in the first example. The emitted ultrasonic wave is emitted from the sensor to the reflection plate, the reflected ultrasonic wave reflected by the reflection plate is received on the sensor side, and the distance between the sensor and the reflection plate is obtained.

As a third example, a sensor that transmits light is disposed at the position where the first to third coils 28 _{1 to} 28 ₃ are disposed in the first example, and the nozzle surface adjustment plate 20 is disposed in the first example. Place the reflector at the position. Light is applied to the reflecting plate, the light reflected by the reflecting plate is received on the sensor side, and the distance between the sensor and the reflecting plate is obtained.

The perspective view of the inkjet coating apparatus of this invention The perspective view of the inkjet coating device in the case of moving the inkjet head of this invention on a board | substrate (A): Front view of the inkjet head of the present invention, (b): Side view of the inkjet head of the present invention, (c): Perspective view of the inkjet head of the present invention. (A): A perspective view of a nozzle plate on which a distance sensor composed of a coil is arranged, (b): an example of a nozzle surface on which a plurality of ejection holes are arranged Configuration diagram of a conventional inkjet coating apparatus (A): The figure explaining the shift | offset | difference of the inkjet discharge position when a board | substrate and a nozzle surface are parallel, (b): The figure explaining the shift | offset | difference of the inkjet discharge position when a nozzle surface inclines with respect to a board | substrate.

Explanation of symbols

1 ...... inkjet coating device 20 ...... nozzle surface adjustment plate 25 ...... parallelism adjustment device 26 ...... head body 28 _{1-28 3} ...... first to third coil 29 ...... vertical movement device 30 ...... inkjet head 32 …… Head fixing plate 33 _{1 to} 33 ₃ …… First to third distance sensor 34 …… Bearing holding member 35 …… Tank portion 36 …… Nozzle plate 37 …… Spherical bearing 38 …… Head body fixing portion 39 ... Discharge holes 41 _{1 to} 41 ₃ ... First to third AC voltage power supplies

Claims (6)

A substrate stage on which the substrate is placed;
An inkjet head configured to be relatively movable with the substrate stage;
A discharge device configured to discharge a discharge liquid to the substrate from a nozzle hole provided in a nozzle surface of the inkjet head;
A nozzle surface adjustment plate is disposed on the substrate stage,
The inkjet head has a position fixed with respect to the nozzle surface, and first to third sensors capable of emitting a detection signal;
A measuring device measured by the first to third sensors;
A nozzle surface adjustment mechanism that changes an angle of the nozzle surface with respect to the nozzle surface adjustment plate;
As a result of the detection signal being emitted from the first to third sensors to the nozzle surface adjustment plate, a measurement signal generated is measured, and the measurement device measures the three points on the nozzle surface and the nozzle surface adjustment plate. Find the distance between
An ink jet coating apparatus capable of making the nozzle surface and the nozzle surface adjustment plate parallel to each other by the nozzle surface adjustment mechanism based on the measurement result. The inkjet head has a vertical movement device for moving the inkjet head up and down,
The measurement device measures a distance between the nozzle surface and the nozzle surface adjustment plate, and determines a predetermined distance between the nozzle surface and the nozzle surface adjustment plate by the vertical movement device based on the measurement result. The ink jet coating apparatus according to claim 1. A coil is provided in each of the first to third sensors,
A metal plate is used for the nozzle surface adjustment plate,
The AC voltage is applied to the first to third coils, the formed magnetic field lines are used as the detection signal, and the AC current flowing through the first to third coils is used as the measurement signal. The inkjet coating apparatus of any one of these. Each of the first to third sensors is provided with first to third ultrasonic emission devices and first to third ultrasonic detection devices, respectively.
An ultrasonic reflector is used as the nozzle surface adjustment plate,
The emitted ultrasonic wave emitted from the ultrasonic wave emission device is used as the detection signal, and the reflected ultrasonic wave reflected by the nozzle surface adjustment plate and detected by the first to third ultrasonic detection devices is used as the measurement signal. The inkjet coating apparatus of any one of Claim 1 or Claim 2. In the first to third sensors, first to third light emitting devices and first to third light receiving devices are provided, respectively.
An end plate is used as the nozzle surface adjustment plate,
The emitted light emitted from the light emitting device is used as the detection signal, and the reflected light reflected by the nozzle surface adjustment plate and detected by the first to third light receiving devices is used as the measurement signal. The inkjet coating apparatus according to any one of 2. A substrate stage on which the substrate is placed;
An inkjet head configured to be relatively movable with the substrate stage;
A discharge device configured to discharge a discharge liquid to the substrate from a nozzle hole provided in a nozzle surface of the inkjet head;
The nozzle of the inkjet head is formed on a nozzle surface adjustment plate made of metal,
The substrate stage has a position fixed with respect to the substrate stage surface, and first to third coils capable of emitting a detection signal;
Measuring devices measured on the first to third coils;
A nozzle surface adjustment mechanism that changes an angle of the surface of the metal plate with respect to the surface of the substrate stage,
Magnetic field lines are emitted as detection signals from the first to third coils to the nozzle surface adjustment plate, an alternating current flowing through the first to third coils is measured as a measurement signal, and the measuring device adjusts the nozzle surface. Calculate the distance between the three points on the plate and the substrate stage,
An inkjet coating apparatus in which the nozzle surface adjustment plate surface and the substrate stage surface are made parallel by the nozzle surface adjustment mechanism from the calculated distance.

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