TW201332788A - Ink-jet apparatus and droplet measuring method - Google Patents

Abstract

The object of the present invention is to provide an ink-jet apparatus and a droplet measuring method which can measure droplet amount of ink in high precision. The solution means is an ink-jet apparatus 1 shown as one embodiment of the present invention, comprising an image pickup device 20. The image pickup device 20 comprises a light source 27, a camera 26, a body 26 and a light emission controlling part 29. The light source 27 is used for irradiating an illuminating ray L to a droplet D of each ink discharged from plural nuzzles. The camera 26 is used for taking an image of the droplet D irradiated by the illuminating ray L. The body 25 is configured to support the light source 27 and the camera 26, and capable of travelling along the orientation direction of these nuzzles. The light emission controlling part 29 is configured to control the quantity of light of the illuminating ray L so as to make the quantity of light captured by the camera 26 is a constant while shooting each droplet every time. A controller 15 is used for measuring volume of the droplet D based on the output of the camera 26, and control a piezoelectric driving part V based on the result of aforesaid measuring.

Description

Inkjet device and droplet measuring method

The present invention relates to an ink jet apparatus and a droplet measuring method capable of measuring the volume of each droplet discharged from a plurality of nozzles of an ink jet head with high precision.

Since the ink jet method allows the ink to be accurately dropped to a specified position on the substrate, it is employed in, for example, a step of manufacturing an organic electroluminescence display. For example, Patent Document 1 listed below discloses a method of forming various luminescent material layers of R (red), G (green), and B (blue) by an inkjet method. Further, it is known that there is a mechanism for determining whether or not the discharge port of the ink is good depending on the form of the liquid droplets ejected from the inkjet head. For example, Patent Document 2 listed below discloses a method in which droplets ejected from an inkjet head are imaged on a discharge path thereof, and whether or not the discharge port is determined based on the image of the droplet.

[Previous Technical Literature] [Patent Document]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2003-77678

Patent Document 2: Japanese Laid-Open Patent Publication No. 2011-2641

In recent years, a technique for controlling the amount of liquid discharged onto a substrate with high precision has been demanded. For example, when the light-emitting layer of an organic electroluminescence display is applied by an inkjet method, since the difference in the amount of ink to be ejected has a large influence on the image quality of the screen, it is necessary to measure the liquid discharged onto the substrate with high accuracy. Drop amount.

In view of the above circumstances, an object of the present invention is to provide an ink jet apparatus and a droplet measuring method capable of measuring the amount of liquid droplets of ink with high precision.

In order to achieve the above object, an inkjet apparatus according to an aspect of the present invention includes a head unit, an image pickup unit, and a controller.

The head portion has a plurality of nozzles arranged in the first axial direction and discharge driving portions respectively attached to the plurality of nozzles.

The imaging unit includes a light source, a camera, a movable portion, and a light emission control unit. The light source is configured to illuminate the liquid droplets of the respective ink jets discharged from the plurality of nozzles from the second axial direction intersecting the first axial direction. The camera is used to obtain an image of a droplet illuminated by the illumination light. The movable portion is configured to support the light source and the camera and is movable in the first axial direction. The light emission control unit controls the amount of illumination light to be fixed, and the amount of light entering the camera is fixed every time the respective droplets are photographed.

The controller is configured to measure a volume of the droplet based on an output of the camera, and control the discharge driving unit based on the measurement result.

A droplet measuring method according to an embodiment of the present invention is a method for measuring a droplet in which a plurality of droplets discharged from a plurality of nozzles are observed at a plurality of different observation positions, and is included in the plurality of observation positions. The background light entering the camera is measured separately.

Illumination light is applied to each of the plurality of observation positions to fix the background light at the plurality of observation positions.

The volume of the droplet is measured by photographing a droplet of the observation position illuminated by the illumination light described above and processing the image.

An inkjet apparatus according to an embodiment of the present invention includes a head unit, an image pickup unit, and a controller.

The head portion has a plurality of nozzles arranged in the first axial direction and discharge driving portions respectively attached to the plurality of nozzles.

The imaging unit includes a light source, a camera, a movable portion, and a light emission control unit. The light source is configured to illuminate the liquid droplets of the respective ink jets discharged from the plurality of nozzles from the second axial direction intersecting the first axial direction. The camera is used to obtain an image of a droplet illuminated by the illumination light. The movable portion is configured to support the light source and the camera and is movable in the first axial direction. The light emission control unit controls the amount of illumination light to be fixed, and the amount of light entering the camera is fixed every time the respective droplets are photographed.

The controller is configured to measure a volume of the droplet based on an output of the camera, and control the discharge driving unit based on the measurement result.

In the above-described inkjet apparatus, the photographing unit photographs each of the droplets ejected from the plurality of nozzles, and the controller measures the volume of the droplet based on the photographed image of the droplet, and drives the discharge driving unit of the inkjet head based on the measurement result. When the respective droplets are photographed by the imaging unit, the imaging unit moves to a position substantially directly below the ejection nozzle of the droplet to be observed, and the dropped droplet is photographed in the air. The volume of the liquid discharged from all the nozzles was measured by performing this treatment one by one for each nozzle.

However, in the case of droplet photography, the amount of light entering the camera may vary depending on the position of the nozzle. In this case, since the brightness of the droplet image outputted from the camera differs depending on the position of the nozzle, the shape of the droplet is observed by image processing, and the accuracy of the measurement is uneven, and it is necessary to have a position at all positions. High precision droplet determination can be difficult.

Therefore, in the above-described inkjet apparatus, the image pickup unit has an emission control unit for controlling the amount of illumination light irradiated from the light source, each time each droplet is The amount of light entering the aforementioned camera is fixed during photography. Thereby, it is possible to prevent the variation of the amount of light at each droplet observation position, and it is possible to achieve high-accuracy droplet measurement without depending on the nozzle position. Further, since it is possible to achieve high-accuracy droplet measurement regardless of the nozzle position, it is possible to achieve high-accuracy discharge amount control regardless of the nozzle position.

Further, the inkjet apparatus may further include an ink supply unit having a container connected to the head portion for storing ink discharged from the plurality of nozzles, and a pressure sensor for measuring a pressure in the container. A pressure adjusting mechanism that adjusts the internal pressure of the above container. In this case, the controller controls the pressure adjusting mechanism such that the inside of the container has a predetermined pressure in accordance with the output of the pressure sensor.

Thereby, the shape of the surface tension surface of the ink adjacent to each of the nozzle discharge ports can be maintained constant, so that the droplets of the desired amount of ink can be stably discharged by the discharge control by the discharge driving unit.

The ink supply unit may further have a liquid level detecting sensor for detecting the height of the ink surface stored in the container, and a replenishing line for replenishing the ink to the container. In this case, the controller is configured to control the supplemental line to set the ink level stored in the container to a predetermined height according to the output of the liquid level detecting sensor.

Thereby, the amount of ink of a predetermined height can be constantly stored in the container, so that the shape of the surface tension surface of the ink adjacent to the discharge port of each nozzle can be maintained constant.

As the liquid level detecting sensor, any configuration can be adopted, and various types of sensors such as an optical type and an electromagnetic type can be used. As an embodiment, the liquid level detecting sensor may be constituted by a single electrostatic capacity sensor with hysteresis.

Thereby, the number of sensors used can be reduced, and the ink can be printed The surface height is maintained in a specified range corresponding to the hysteresis of the electrostatic capacity sensor.

The controller may control the light emission control unit to measure the amount of light in a partial region of the captured image obtained by the camera, and fix the amount of light in the region every time the respective droplets are photographed.

Thereby, the measurement environment of the liquid droplets discharged from the respective nozzles can be made uniform, and the measurement accuracy of the volume can be improved.

In this case, when the diameter of the droplet is d and the area of the above region is S0, the relationship of 0.5 × d ² ≦ S0 ≦ 50 × d ² can be set.

Thereby, the volume measurement of the droplets with high precision can be achieved, and the uniformity of the measurement environment between nozzles can be achieved.

A droplet measuring method according to an embodiment of the present invention is a method for measuring droplets in which a plurality of droplets discharged from a plurality of nozzles are observed at a plurality of different observation positions, wherein the method includes: The observation position respectively determines the background light entering the camera; Illuminating the illumination light at each of the plurality of observation positions to fix the background light at the plurality of observation positions; The volume of the aforementioned droplet is measured by photographing the droplet of the observation position illuminated by the aforementioned illumination light and processing the image.

In the above-described measurement method, since the illumination light is irradiated so that the amount of light entering the camera is fixed every time the respective droplets are photographed, the amount of light at each droplet observation position can be prevented from being uneven. The nozzle position varies to achieve high accuracy droplet measurement.

In the above droplet measuring method, the ink discharge from the nozzle for discharging the liquid droplet in the plurality of nozzles may be controlled according to the volume of the liquid droplets. the amount.

Thereby, it is possible to achieve high-precision discharge amount control regardless of the nozzle position.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a schematic plan view showing an ink jet apparatus according to an embodiment of the present invention, and Fig. 2 is a schematic side view thereof. In each of the figures, the X-axis and the Y-axis indicate horizontal directions perpendicular to each other, and the Z-axis indicates a vertical direction perpendicular to the X-axis and the Y-axis, respectively.

The ink jet apparatus 1 of the present embodiment has a stage 11 for supporting the substrate S, a head module 12 for applying droplets of ink onto the substrate S on the stage 11, and for moving the stage 11 in a uniaxial direction. The moving mechanism 13 and the maintenance unit 14. The inkjet apparatus 1 of the present embodiment is configured as, for example, a manufacturing apparatus of an organic electroluminescence display in which an organic electroluminescence layer is formed on a substrate S.

The substrate S is formed of a substantially rectangular glass substrate. The size of the substrate S is not particularly limited, and is, for example, 1850 mm in width and 1500 mm in length. As the substrate S, in addition to the above, a substrate such as a plate, a sheet, or a film of metal, plastic, or paper may be used. Further, the substrate S is not limited to a single layer, and may be a multilayer film having an insulating film, a conductive film, or the like, or a functional film patterned into a predetermined shape. structure.

The stage 11 is provided to be movable on the base portion 10 in the Y-axis direction. The platform 11 has a support surface 11a for supporting the substrate S. The support surface 11a belongs to a plane (XY plane) parallel to the X-axis direction and the Y-axis direction, and is configured by a substantially rectangular flat surface in the present embodiment. The stage 11 may also be provided with various clamp mechanisms for holding the substrate S on the support surface 11a.

The moving mechanism 13 includes a pair of guide rails 13a and 13b laid on the base portion 10, a drive source for moving the platform 11 along the guide rails 13a and 13b, and a control unit for controlling the drive source. Wait. The pair of guide rails 13a, 13b extend in parallel along the Y-axis direction, and the stage 11 is provided on the guide rails 13a, 13b. The driving source is disposed inside the platform 11, and the control unit causes the platform 11 to perform high-accuracy movement control along the guide rail.

The head module 12 has a plurality of ink jet heads 121, 122, 123, 124, 125, and 126 (head portions). The inkjet heads 121 to 126 are configured to apply a specified ink droplet to the entire surface of the substrate S on the stage 11 that moves in the Y-axis direction along the guide rails 13a and 13b. Further, the head module 12 may be provided with a lifting mechanism portion for moving the inkjet heads 121 to 126 in the Z-axis direction. Further, the number of ink jet heads is not limited to the illustrated example, and a larger number of ink jet heads may be used to constitute the head module.

The inkjet heads 121 to 126 have a plurality of nozzles arranged at a predetermined pitch along the longitudinal direction thereof, and are configured to discharge droplets of a predetermined amount of ink from the respective nozzles. The ink contains a luminescent material for forming an organic light-emitting layer. The inkjet heads 121 to 126 are arranged to correspond to a plurality of regions of the entire surface of the substrate S on the stage 11 arranged in the X-axis direction. The region defined on the surface of the substrate S is formed into a rectangle formed by a width direction parallel to the Y-axis direction and a width direction parallel to the X-axis direction, and the inkjet heads 121 to 126 are configured to drop ink droplets. These areas are applied to the respective areas at a predetermined pitch in the X-axis direction and the Y-axis direction, respectively.

The head module 12 has a plurality of rotating mechanism portions M for rotating the ink jet heads 121 to 126 around the Z axis. The rotation mechanism portions M are respectively provided in the support frame 120, and are configured to allow the respective inkjet heads 121 to 126 Rotate within a specified angle range around the Z axis, and the coating pitch of the droplets can be arbitrarily adjusted along the X-axis direction. These rotating mechanism portions M are controlled by the controller 15. In the present embodiment, the longitudinal direction of each of the inkjet heads 121 to 126 is set to be in the X-axis direction.

The controller 15 is typically constituted by a computer including a CPU and various memories. The controller 15 controls the driving of various mechanism units such as the head module 12, the moving mechanism 13, and the maintenance unit 14. The controller 15 may be provided on the base portion 10 or at a position other than the base portion 10.

FIG. 3 is a plan view showing a schematic configuration of the ink jet head 121. Further, since the ink jet heads 121 to 126 have the same configuration, the ink jet head 121 will be described as an example.

In the ink discharge surface 121s of the inkjet head 121, a plurality of nozzles N along the longitudinal direction (the X-axis direction in the drawing) are arranged at a predetermined pitch. The number of the nozzles N is not particularly limited, and a larger number of nozzles than the illustrated example can be formed. The nozzle diameter is not particularly limited. In the present embodiment, the nozzle diameter of the nozzle N is, for example, 30 μm in diameter.

The inkjet head 121 is connected to the ink supply unit 40. The ink supply unit 40 is provided with a container 41 for storing the ink W. A passage 42 for supplying the ink W in the container 41 to the nozzle N is formed inside the inkjet head 121. Further, a piezoelectric driving unit (discharging driving unit) V is provided in each of the nozzles N, and a predetermined amount of ink droplets D are ejected from the respective nozzles N by driving control from the controller 15.

The ink supply unit 40 further has a pressure sensor 43 and a pump unit 44 (pressure adjustment mechanism). The pressure sensor 43 is configured to measure the pressure in the container 41 and output it to the controller 15. The pump unit 44 contains a vacuum pump, a vacuum pump, etc., and is controlled by the controller 15.

The controller 15 controls the pump unit 44 in accordance with the output of the pressure sensor 43 to bring the inside of the container 41 to a specified pressure (negative pressure). Thereby, since the shape of the surface tension surface of the ink adjacent to the discharge port of each nozzle N can be maintained constant, it is possible to stably discharge the droplets of the desired amount of ink by the discharge control by the discharge driving unit. The pressure specified above can be set, for example, to -5 kPa to -3 kPa.

The ink supply unit 40 further has a liquid level detecting sensor 45 and a complementary line 46 for ink. The liquid level detecting sensor 45 is configured to detect the liquid level of the ink stored in the container 41 and supply the output to the controller 15. The replenishing line 46 includes a pipe 46a connected between the tank 47 for storing the ink for replenishment and the container 41, and an on-off valve 46b provided in the pipe 46a, and is configured to open the on-off valve 46b in accordance with the output from the controller 15. The container 41 replenishes the ink.

The controller 15 controls the replenishing line 46 in accordance with the output of the liquid level detecting sensor 45 so that the liquid level of the ink stored in the container 41 becomes only a predetermined height of the ink level of the ink stored in the container 41. Thereby, the amount of ink of a predetermined height can be constantly stored in the container, so that the shape of the surface tension surface of the ink of each nozzle discharge port can be maintained constant. Therefore, the discharge control by the droplet D of the discharge driving portion V can be stably performed.

The liquid level detecting sensor 45 may be a laser optical sensor or an electromagnetic sensor using an electromagnetic field. In the present embodiment, as the liquid level detecting sensor 45, a single electrostatic capacitance sensor with hysteresis is used.

Fig. 4 is a timing chart showing the relationship between the liquid level height (A) and the opening and closing state (B) of the opening and closing valve 46b. Fig. 5 is a view showing the change in the liquid level of the ink in the container 41. The liquid level detecting sensor 45 is disposed at a reference height of the side wall of the container 41 from the bottom of the container 41. Liquid level detecting sensor 45 The system is configured to detect a change in electrostatic capacitance when the liquid level of the ink drops from a state exceeding the reference height to a level lower than the reference height, or static electricity when the liquid level of the ink changes from below the reference height to the reference height The change in capacity.

For example, as shown in FIGS. 4 and 5(A) and (B), the liquid level detecting sensor 45 is in an "on" state when the liquid level is lowered from the reference height to a predetermined height. The ink is supplied from the replenishing line 46 to the container 41. Further, as shown in FIGS. 4 and 5(B) and (C), the liquid level detecting sensor 45 is turned "off" when the liquid level reaches the reference height, whereby the ink from the replenishing line 46 can be stopped. Supplement.

By using a sensor with hysteresis to detect the liquid level, a single sensor can be used to detect the liquid level, thereby reducing the number of sensors used. And the liquid level of the ink can be automatically controlled within the range of hysteresis. Furthermore, the variation of the surface tension pressure can be suppressed to a minimum. In the present embodiment, the liquid level height is set to a range from the ink discharge surface 121s to the liquid level of the ink W in the container 41 in the range of 50 mm to 60 mm.

Next, the details of the maintenance unit 14 will be described.

When the nozzle unit 12 applies a droplet to the substrate S by the head module 12, the maintenance unit 14 stands by in the non-operation area as shown in FIG. On the other hand, when the inkjet device 1 is being repaired, the maintenance unit 14 moves directly under the head module 12, acquires an image of the liquid droplets discharged from the inkjet heads 121 to 126, and supplies the acquired image. Go to controller 15. The controller 15 measures the volume of the droplet by performing image processing on the acquired image of the droplet image, and determines whether the volume value is a specified range or not. Further, the controller 15 controls the amount of ink discharged from the nozzle to control the volume of the liquid droplets to be within the predetermined range. Moreover, the controller 15 memorizes or updates the driving voltage of the adjusted piezoelectric driving portion V with each nozzle on the substrate. In the processing of S, each of the piezoelectric driving portions V is driven in accordance with the stored or updated driving voltage.

The maintenance unit 14 has an imaging unit 20 for capturing droplets ejected from the inkjet heads 121 to 126. The imaging unit 20 is disposed on the support table 21 provided on the guide rails 13a and 13b, and is configured to be movable in the Y-axis direction by the movement mechanism 13. Further, the imaging unit 20 is disposed on the pair of guide rails 23a and 23b which are laid on the support table 21 in parallel with the X-axis direction, and is configured to be movable in the X-axis direction by the moving mechanism 13.

FIG. 6 is a schematic side view showing the configuration of the imaging unit 20. The imaging unit 20 has a base 24 and a body 25 provided thereon. The base 24 is provided with drive rails 22a and 23b, and drive sources 22a and 22b such as a linear motor that travels on the guide rails 23a and 23b by the drive control of the moving mechanism 13. The body 25 constitutes a movable portion that is movable in the X-axis direction and the Y-axis direction, respectively.

The imaging unit 20 has a camera 26 that photographs the droplets D ejected from the inkjet heads 121 to 126 on the flight path thereof, and a light source 27 that illuminates the droplets D with the illumination light L. The camera 26 and the light source 27 are supported by the body 25, and are housed inside the body 25 in the present embodiment.

The camera 26 is composed of a solid-state imaging device such as a CCD (charge coupled device) or a CMOS (Complementary Metal-Oxide Semiconductor), and outputs image data of the obtained droplet D. Go to controller 15. The light source 27 can be a light emitting diode or a fluorescent lamp or the like. The light source 27 is for generating pulse light as the illumination light L, and is configured to continuously change the intensity, the illuminance, and the brightness in accordance with the output of the light emission control unit 29 to be described later. The light emission control unit 29 may be integrally assembled with the light source 27 or may be incorporated inside the controller 15.

The body 25 has a recess 25s for forming a photographing space of the droplet D. The illumination light L is used to illuminate the droplet D flying in the Z-axis direction from the Y-axis direction in the concave portion 25s; the camera 26 photographs the droplet D with the illumination light L as a background. In the present embodiment, the first mirror 28a for reflecting the illumination light L irradiated from the light source 27 in the Y-axis direction and the second mirror 28b for reflecting the droplet image irradiated by the illumination light L toward the camera 26 are provided. . The camera 26 is used to photograph a droplet image and output the photographic image to the controller 15.

The imaging unit 20 further has a rotation mechanism portion 30 that allows the body 25 to rotate around the base 24 in parallel with the Z-axis. The rotation mechanism unit 30 is configured to adjust the machine body 25 to an arbitrary rotation angle in accordance with the nozzle arrangement direction of the inkjet heads 121 to 126. Further, the rotation mechanism unit M of the inkjet heads 121 to 126 may be driven, and the rotation of the body 25 may be performed by the inkjet heads 121 to 126.

As shown in FIG. 3, the maintenance unit 14 is configured to sequentially move the imaging unit 20 in the arrangement direction (X-axis direction) of the nozzles N, and to photograph the droplets D discharged from the respective nozzles N one by one. In the present embodiment, the position of the nozzle N that is necessary to be observed in the plurality of nozzles N is set as the observation position, and the nozzle unit N is ejected to the target nozzle N in a state where the imaging unit 20 is stationary at different observation positions for each nozzle. The droplet D is photographed. By performing this process for each nozzle, the volume of droplets ejected from all of the nozzles can be measured.

The controller 15 measures the volume of the droplet D by the image data of each droplet D output from the camera 26 by a predetermined arithmetic deduction. The image processing method is not particularly limited, and a representative includes a process of determining the outer shape (contour) of the droplet image from the difference in brightness between the droplet image and the background image. Since the volume of the droplet D can be converted into the amount of ink, the controller 15 can judge whether or not the obtained volume value is within the specified range. If the volume of the droplets of photography is the above range In other cases, the controller 15 adjusts the amount of ink discharged from the nozzle so that the volume of the droplet becomes within the specified range.

However, the amount of light entering the background light of the camera during droplet photography may vary depending on the position of the nozzle. In this case, the brightness of the droplet image outputted from the camera differs depending on the position of the nozzle, so that the shape of the droplet is observed by image processing, and the accuracy of the droplet is uneven, and the nozzle position is highly accurate at all nozzle positions. It is difficult to measure the droplets.

Therefore, in the present embodiment, the light emission control unit is configured to control the amount of illumination light emitted from the light source 27, and the amount of light entering the camera 26 is fixed every time the respective droplets D are photographed. Thereby, it is possible to prevent the difference in the amount of light at each droplet position, and it is possible to measure the droplet with high accuracy without depending on the position of the nozzle.

In order to carry out such processing, the controller 15 performs a process of measuring the background light entering the camera 26 at a plurality of observation positions before measuring the droplet D. At this time, illumination light of a certain amount of light may be irradiated from the light source 27. The controller 15 measures the brightness of the image of the set image for each of the observed positions corresponding to the plurality of nozzle positions. For example, FIG. 7(A) shows the measurement result of the luminance Y at each observation position. N1 to N5 on the horizontal axis are expediently assigned nozzle numbers for the respective nozzles.

Next, as shown in Fig. 7(B), the controller 15 determines the amount of illumination light L emitted from the light source 27 for each observation position, so that the background light entering the camera 26 at each observation position becomes a constant luminance Y0. The brightness Y0 can be set to any value.

In the present embodiment, the controller 15 performs the light emission control of the light source 27 and the control of the liquid droplet discharge from the nozzle N so that the liquid droplet D can be photographed in a partial region of the captured image of the camera 26.

FIG. 8 is a schematic diagram showing a photographic image U of a droplet obtained by the camera 26. Usually, the photographic image U will have different amounts of light depending on the position. The controller 15 has to adjust the imaging position so that the droplet D passes through the specific region P of the substantially central portion of the photographic image U. Thus, the controller 15 is configured to photograph the droplet D when the droplet is located in the region P. In the figure, the X-axis direction (the horizontal direction of the substrate) hardly varies, and the Z-axis direction (the vertical direction of the substrate) is the falling direction of the droplet D, so control of the photographing time point is necessary. The shape of the region P is set to a square shape, but may be other shapes such as a circle or a rectangle.

Further, the controller 15 controls the light source 27 which measures the amount of light (for example, luminance) in the region P so that the amount of light in the region P is fixed each time the ink droplets are photographed. Typically, the controller 15 controls the luminous intensity of the light source 27, and measures the average luminance of the region P so that the average luminance of the region P is fixed each time the droplet D is photographed. Thereby, the measurement environment of the droplets D discharged from the respective nozzles can be made uniform, and the measurement accuracy of the volume can be improved.

The area of the region P is not particularly limited, and is typically set to be larger than the area of the droplet D. As an example, the area S0 [mm ² ] of the region P is set to 0.5 × d ² ≦ S0 ≦ 50 × d ² when the droplet D is regarded as a sphere and its diameter is d [mm]. Thereby, a highly accurate volume measurement of the liquid droplets can be achieved, and the measurement environment between the nozzles can be achieved.

That is, in the case where the area of the region p is smaller than (0.5 × d ² ), the liquid droplet D cannot be stably accommodated in the region P, and it is difficult to measure the volume with high precision. Further, if the area of the region P exceeds (50 × d ² ), since the dark region around the screen U also belongs to the region P, the uniformity of the brightness in the region P is lowered, and even the measurement between the nozzles is performed. The environment is difficult to unify. The area of the region P is preferably (1 × d ² ) ≦ S0 ≦ (10 × d ² ).

Next, the controller 15 causes the droplets to be actually ejected from the plurality of nozzles N, and the imaging unit 20 performs the photographing of the droplets D for each of the nozzles N. At this time, the controller 15 controls the light emission control unit 29 to generate the illumination light L for determining the amount of light for each nozzle from the light source 27 as described above. Thereby, the droplet D can often be photographed at a fixed amount of light at all nozzle positions. Further, since it is possible to achieve high-accuracy droplet measurement regardless of the nozzle position, it is possible to achieve high-accuracy discharge amount control regardless of the nozzle position.

As described above, according to the present embodiment, the difference between the measured volume and the actual volume of the liquid droplets discharged from the respective nozzles can be made 0.3% or less of 1 σ/average value. Since the volume control of such high-precision droplets can be achieved, the variation in the amount of ink can be reduced, and a uniform droplet layer can be formed in the plane of the substrate. Thereby, an organic electroluminescence display excellent in in-plane distribution of light emission luminance can be manufactured.

The embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various changes can be made without departing from the spirit and scope of the invention.

For example, in the maintenance unit 14, an ink suction unit or the like for cleaning the ink discharge surface 121s of the inkjet heads 121 to 126 may be provided in addition to the image pickup unit 20.

Moreover, in order to improve the measurement accuracy of the droplet D by the imaging unit 20, the number of pixels of the camera 26 can be increased to achieve high resolution, or short-wavelength light (for example, blue light) for illumination light, and shortened. The illumination time of the illumination light (for example, 1 microsecond or less).

1‧‧‧Inkjet device

10‧‧‧Base section

11‧‧‧ platform

11a‧‧‧Support surface

12‧‧‧ nozzle module

13a, 13b‧‧‧ rails

14‧‧‧Maintenance Department

15‧‧‧ Controller

20‧‧‧ camera unit

21‧‧‧Support desk

22a, 22b‧‧‧ drive source

23a, 23b‧‧‧ rails

24‧‧‧Abutment

25‧‧‧ body

26‧‧‧Camera

27‧‧‧Light source

28a‧‧‧1st mirror

28b‧‧‧2nd mirror

29‧‧‧Lighting Control Department

40‧‧‧Ink Supply Department

41‧‧‧ Container

42‧‧‧ pathway

43‧‧‧ Pressure sensor

44‧‧‧ pump unit

45‧‧‧liquid level sensor

46‧‧‧Supply pipeline

46a‧‧‧Pipe

46b‧‧‧ switch valve

47‧‧‧ slot

120, 120a, 120b‧‧‧ support framework

121, 122, 123, 124, 125, 126‧‧ ‧ inkjet head

121s‧‧‧Ink and ink spit out

D‧‧‧ droplets

M‧‧‧Rotating Mechanism Department

N‧‧‧ nozzle

N1, N2, N3, N4, N5‧‧‧ nozzle number

L‧‧‧Lights

P‧‧‧Specific central area of the photographic image

S‧‧‧Substrate

V‧‧‧Piezoelectric drive department

U‧‧‧Photographic image

W‧‧‧Ink

X, Y, Z‧‧ direction axis

Fig. 1 is a schematic plan view showing an ink jet apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic side view showing the above ink jet apparatus.

3 is a schematic plan view showing a configuration of an ink jet head and an ink supply unit in the ink jet apparatus.

4(A) and 4(B) are timing charts for explaining the action of the liquid level detecting sensor in the ink supply unit.

5(A) to 5(C) are schematic views showing changes in the liquid level of the ink in the container in the ink supply unit.

Fig. 6 is a schematic side view showing the configuration of an image pickup unit in the above ink jet apparatus.

Fig. 7 is a view for explaining an example of control of the amount of light of each nozzle position in the image pickup unit, wherein A represents the brightness of the background light before the control of each nozzle position, and B represents the background light after the control of each nozzle position. brightness.

Fig. 8 is a view showing a photographic image of a droplet obtained by the above-described image pickup unit.

41‧‧‧ Container

45‧‧‧liquid level sensor

W‧‧‧Ink

Claims (10)

An ink jet apparatus comprising: a head unit having a plurality of nozzles arranged in a first axial direction; and a discharge driving unit respectively mounted on the plurality of nozzles; and an imaging unit having a light source for use Illuminating light from each of the ink droplets discharged from the plurality of nozzles from a second axis direction intersecting the first axis direction; and a camera for acquiring an image of the liquid droplets illuminated by the illumination light; a movable portion configured to support the light source and the camera and movable along the first axis direction, and a light emission control portion for controlling the amount of illumination light for each of the aforementioned droplets The amount of light entering the camera is fixed; and the controller is configured to measure the volume of the droplet according to the output of the camera, and control the discharge driving unit according to the measurement result. An inkjet device according to claim 1, further comprising: an ink supply unit having: a container connected to the head portion for storing ink discharged from the plurality of nozzles; and measuring the inside of the container a pressure pressure sensor; a pressure adjusting mechanism capable of pressure-adjusting the inside of the container; the controller is configured to control the pressure adjusting mechanism to make the inside of the container a designated pressure according to the output of the pressure sensor . The inkjet device of claim 1 or 2, wherein the ink supply portion further has a liquid level detecting sensor for detecting the height of the ink surface stored in the container, and for supplementing the ink Ink to the supplementary line of the aforementioned container; the controller is used to control the aforementioned supplementary line to be in accordance with the aforementioned liquid level The output of the sensor is detected such that the ink level stored in the container becomes a designated height. The ink jet device of claim 3, wherein the liquid level detecting sensor is composed of a single electrostatic capacity sensor with hysteresis. The inkjet device of claim 1, wherein the controller measures the amount of light in a portion of the image captured by the camera, and causes the amount of light in the region to be The aforementioned light emission control unit is controlled in a fixed manner. The ink-jet apparatus of claim 5, wherein when the diameter of the droplet is set to d, and the area of the region is set to S0, it satisfies the following formula: 0.5 × d ² ≦ S0 ≦ 50 × d ² Relationship. A method for measuring droplets, characterized in that it is a droplet measuring method for detecting a plurality of droplets discharged from a plurality of nozzles at a plurality of different observation positions; and is in the plurality of observation positions The background light entering the camera is measured, and the illumination light is irradiated at each of the plurality of observation positions, so that the background light at the plurality of observation positions is fixed, and the liquid droplets passing through the observation position illuminated by the illumination light are photographed by a camera. And processing the image to determine the volume of the aforementioned droplets. The liquid droplet measuring method according to claim 7, wherein the ink discharge amount from the nozzle for discharging the liquid droplets from the plurality of nozzles is further controlled according to the volume of the liquid droplets. The method for measuring a droplet according to claim 7 or 8, wherein the step of measuring the volume of the droplet comprises measuring an average brightness of a partial region of the photographic image obtained by the camera, each of the aforementioned droplets The illumination light is controlled such that the brightness of the aforementioned area is fixed during photographing. The liquid droplet measuring method according to claim 9, wherein when the diameter of the droplet is set to d and the area of the region is S0, the system satisfies the following formula: 0.5 × d ² ≦ S0 ≦ 50 × d ² relationship.