JP2017013000A - Droplet measuring method and droplet measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet measuring method and a droplet measuring system in which a measuring time can be shortened and measuring accuracy can be secured.SOLUTION: A droplet measuring method comprises: a discharging and coating process S20 of discharging plural droplets from at least a part of nozzles of a line head 9 on a substrate; an imaging process S40 of imaging the droplets; a correspondence table preparing process S60 of preparing a correspondence table showing a correspondence relationship of an inclination at a position on the three dimensional coordinate system of the surface of the droplet and brightness information corresponding to the position, on the basis of the brightness information obtained in the imaging process, about at least a part of the droplets; and a droplet evaluating process S70 which finds the volume or the surface shape of the droplet by using the brightness information obtained in the imaging process S40 and the correspondence table.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a droplet measuring method and a droplet measuring system.

  As a method of manufacturing a device such as a color filter of a liquid crystal display or an organic EL display, for example, a liquid material containing a functional material is ejected as droplets from a plurality of nozzles by an ink jet method, and the functional material film is applied to the ejection target A method of forming is known.

  In this case, it is an important step to obtain the correspondence between the setting of the control device that controls the discharge amount of the droplet and the actual discharge amount of the droplet, and to control the discharge amount to a constant value. This is because if the discharge amount is not uniform, a difference in the film thickness of the functional material leads to a device failure. For example, in the case of a color filter or an organic EL display, the difference in film thickness is observed as uneven color or uneven brightness.

  In order to investigate the actual ejection amount, when using an ink with a polymer solute, for example, the ink is ejected / applied to a glass substrate and the solvent is dried, and then, for example, white interference or confocal A method of measuring the volume of a solute using a height measuring device such as the above is known (for example, see Patent Document 1).

  Further, a method is known in which the height of a droplet is measured using a laser type distance measuring device and the volume of the droplet is calculated (see, for example, Patent Document 2).

JP 2010-240503 A Japanese Patent No. 4093167

  However, the conventional droplet measuring method using a white interference or a confocal height measuring device has a problem in that it takes time to measure due to the measurement principle. In particular, in a large-screen display manufacturing apparatus, the number of nozzles used for inkjet printing exceeds 100,000, so even if the measurement time per droplet is 1 second, at least 28 is required to measure all droplets. Since it takes time, it has a great influence on the operating rate of the equipment, which is a big issue in considering mass production.

  In addition, in order to shorten the measurement time, there is a droplet measurement method in which the area is measured not by the droplet volume but by the image recognition device. However, since the variation in the height direction due to the drying condition of the droplet cannot be measured, the measurement accuracy There was a problem that could not be secured.

  That is, in the conventional droplet measuring method, there is a trade-off between shortening the measurement time and ensuring the measurement accuracy.

  An object of the present invention is to provide a droplet measurement method and a droplet measurement system that can shorten measurement time and ensure measurement accuracy in view of the problems in the conventional droplet measurement method. To do.

In order to solve the above problems, an ejection process for ejecting a plurality of droplets from at least some nozzles of the head onto the substrate, an imaging process for imaging the droplets, and at least some of the droplets of the droplets Based on the luminance information obtained in the imaging step, a correspondence table is created that represents the correspondence between the inclination of the surface of the droplet at a position on the three-dimensional coordinate system and the luminance information corresponding to the position. A droplet measurement method comprising: a correspondence table creation step; and a droplet evaluation step for determining the volume or surface shape of the droplet using the luminance information obtained in the imaging step and the correspondence table is used. .

  A discharge step of discharging a plurality of droplets from at least some of the nozzles of the head onto the substrate; an imaging step of imaging the droplets discharged onto the substrate in the discharge step; and a liquid on the substrate prepared in advance Using the correspondence table representing the correspondence between the inclination of the surface of the droplet on the three-dimensional coordinate system and the luminance information corresponding to the position, and the luminance information obtained in the imaging step, the droplet And a droplet evaluation method for determining the volume or surface shape of the droplet.

  An ejection process for ejecting a plurality of droplets from at least some nozzles of the head onto the substrate, an imaging process for imaging the droplets, and a droplet shape using the luminance information of the droplets obtained in the imaging process A classification step for classifying the liquid droplets into a plurality of groups, and at least some of the droplets classified in the classification step correspond to the inclination of the surface of the droplet on the three-dimensional coordinate system and the position A correspondence table creation step for creating a correspondence table representing a correspondence relationship with the luminance information for each classified group, the luminance information obtained in the imaging step, and the correspondence table created for each classified group And a droplet evaluation step for determining the volume or surface shape of the droplet.

  A head having a plurality of nozzles for discharging droplets; an imaging unit for imaging the plurality of droplets discharged from at least some of the nozzles on the substrate; and at least some of the droplets Based on the luminance information obtained by the imaging unit, a correspondence table representing the correspondence between the inclination of the surface of the droplet on the three-dimensional coordinate system and the luminance information corresponding to the position is created. Using the correspondence table creation unit, the luminance information obtained by the imaging unit and the correspondence table created by the correspondence table creation unit, a droplet evaluation unit for obtaining the volume or surface shape of the droplet, Is used.

  Based on luminance information of a plurality of droplets on a substrate ejected from at least some nozzles of the head and a plurality of nozzles that eject droplets, on the three-dimensional coordinate system of the surface of the droplets A correspondence table creation unit that creates a correspondence table representing a correspondence relationship between the inclination at the position and the luminance information corresponding to the position, and images the plurality of droplets ejected from at least some of the nozzles onto the substrate. And a droplet evaluation unit that obtains the volume or surface shape of the droplet using the luminance information obtained by the imaging unit and the correspondence table created by the correspondence table creation unit. A drop measurement system is used.

  A head portion that discharges a plurality of droplets from at least some nozzles of the head onto a substrate, an imaging portion that images the droplets, and a droplet shape using the luminance information of the droplets obtained in the imaging step A classification unit that classifies the liquid droplets into a plurality of groups, and at least some of the droplets classified by the classification unit correspond to the inclination of the surface of the droplet in the three-dimensional coordinate system and the position A correspondence table creation unit that creates a correspondence table representing a correspondence relationship with the luminance information for each classified group, the luminance information obtained by the imaging unit, and the correspondence table created for each classified group And a droplet evaluation system for determining the volume or surface shape of the droplet.

  According to the present invention, measurement time can be shortened and measurement accuracy can be ensured.

1 is a schematic perspective view of a droplet discharge device included in a droplet measurement system according to Embodiment 1 of the present invention. Schematic flowchart explaining the droplet measurement method of the first embodiment Sectional drawing which shows the structure of the board | substrate used with the droplet measuring method of this Embodiment 1. The schematic diagram showing the relationship between the maximum angle which injects into the objective lens calculated from the numerical aperture of the objective lens of a camera, and the contact of a droplet in the droplet measuring method of this Embodiment 1. FIG. (A)-(c): The figure explaining the basis of the minimum of the contact angle (alpha) shown to (Formula 2) of this Embodiment 1. FIG. (A)-(c): The figure explaining the basis of the upper limit of the contact angle (alpha) shown to (Formula 2) of this Embodiment 1. FIG. Schematic front schematic diagram showing a droplet application pattern (a type in which two dummy droplets are arranged) of a volume measurement droplet sample used in the imaging step and the shape measurement step of the droplet measurement method of the first embodiment Schematic front schematic diagram showing a droplet application pattern (a type in which one dummy droplet is arranged) of a volume measurement droplet sample used in the imaging step and the shape measurement step of the droplet measurement method of the first embodiment Schematic front schematic diagram showing a volume measurement pattern when droplets are sufficiently separated in the droplet measurement method of the first embodiment A graph showing the relationship between the apex height and diameter of the droplet in the A-B section of FIG. (A): Schematic diagram showing the shape change of a droplet that dries quickly, (b): Schematic diagram showing the shape change of a droplet that dries slowly. Schematic diagram showing the overall configuration of the imaging mechanism in the first embodiment Flow chart for explaining a droplet evaluation step of the droplet measurement method according to the first embodiment (A)-(e): The figure explaining the preparation method of the corresponding | compatible table of the droplet measuring method in this Embodiment 1. FIG. FIG. 6 is a diagram for explaining a method of converting the inclination of a surface of one droplet at a position on a three-dimensional coordinate system as a vector component in the two-dimensional coordinate system in the first embodiment. The figure explaining the method of calculating | requiring the height in the position on the three-dimensional coordinate system of the surface of one droplet in this Embodiment 1. FIG. Schematic diagram of droplets for explaining a method of calculating the volume of the droplets in Embodiment 1 of the present invention Schematic flowchart showing a second droplet measurement method according to an embodiment of the present invention Schematic flowchart showing a third droplet measurement method according to an embodiment of the present invention Schematic flowchart showing a fourth droplet measuring method according to the embodiment of the present invention. Schematic flowchart showing a fifth droplet measuring method according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
Hereinafter, embodiments of a droplet measuring method and a droplet measuring system according to the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments.

  The droplet measurement system according to the present embodiment includes a droplet discharge device 50, a decompression chamber (not shown), and a droplet shape measurement device (not shown).

  FIG. 1 is a schematic perspective view of a droplet discharge device 50 included in the droplet measurement system of the present embodiment.

  The decompression chamber is used when drying the droplets applied to the substrate, which will be described later. The droplet shape measuring device is a device that extracts a droplet at a predetermined position from all droplets discharged from all nozzles to be evaluated and measures the shape of the extracted droplet. This will be described later.

  As shown in FIG. 1, the print object 1 is installed on a table 3 at a position in the vertical downward direction of the head unit 2. The table 3 is attached to a stage 11 having a drive system and is conveyed in the X direction. On the stage 11, a torii-like gantry 6 constituted by a pair of leg portions 4, the leg portions 4 and a support portion 5 attached above the leg portions 4 is fixed.

  Further, the front surface of the gantry 6 is connected to a support base 7 having a lifting shaft in the lifting direction (see the Z-axis direction in FIG. 1), and is movable in the vertical direction (see the Z-axis direction in FIG. 1). It has become. The head unit 2 is disposed on the support base 7, and the head unit 2 includes a distribution tank 8 and a line head 9. The gap between the printing object 1 and the line head 9 is adjusted by the movement in the up-down direction Z.

  The line head 9 includes a plurality of droplet discharge module heads 10 including a plurality of nozzles (not shown) for discharging ink and piezoelectric actuators (not shown) corresponding to the nozzles.

  Further, as shown in FIG. 1, the droplet discharge device 50 includes an imaging mechanism 20 having a camera 601 and the like that can image all droplets applied to the print target 1 above the table 3. Yes. The imaging mechanism 20 will be further described later with reference to FIG.

  As shown in FIG. 1, the droplet discharge device 50 includes a control unit 12, and the control unit 12 supplies power and a control signal for each head to each droplet discharge module head 10. At the same time, a control signal is also supplied to the X and Z drive shafts, and a control signal is also supplied to the imaging mechanism 20 used when measuring a droplet. In addition, the control unit 12 includes a correspondence table creation unit 120 and a volume calculation unit 130 which will be described later.

  The imaging mechanism 20 of the present embodiment corresponds to an example of an imaging unit of the present invention, and the volume calculation unit 130 corresponds to an example of a droplet evaluation unit of the present invention.

  As described above, the line head 9 includes the droplet discharge module heads 10 arranged over the entire width of the print target 1. For this reason, during the printing operation, while the printing object 1 is conveyed in the X direction, the droplets are ejected from the line head 9 at a predetermined timing by a control signal from the control unit 12. It is possible to form a desired image over the entire width.

  Next, an embodiment of a droplet measurement method performed using the droplet measurement system of the present embodiment will be described with reference to FIG.

  FIG. 2 is a schematic flow diagram illustrating the droplet measurement method of the present embodiment.

  As shown in FIG. 2, the droplet measuring method according to the present embodiment includes a substrate creation step S10, a discharge / application step S20, a drying step S30, an imaging step S40, a shape measurement step S50, and a correspondence table creation. Step S60 and droplet evaluation step S70 are provided.

  That is, in the substrate forming step S10, UV light is irradiated onto a substrate having a polymer film having a water repellent surface so that the angle between the droplet and the water repellent film becomes a predetermined contact angle. In the ejection / application process S20, a droplet is ejected from the nozzle to be evaluated toward the polymer film using an inkjet method, and the ink is applied to the polymer film. It is a process.

  The drying step S30 is a step in which the substrate on which the ink is applied is placed in a reduced pressure chamber (not shown), and the ink applied to the polymer film is dried while reducing the pressure. The imaging step S40 is dried. In this step, the ink droplets are imaged by a camera.

  Note that the decompression chamber may be mounted on the droplet discharge device 50, or may not be mounted on the droplet discharge device 50 and may be installed alone outside the device.

  In the shape measuring step S50, a plurality of droplets are extracted from the droplets on the substrate used in the imaging step S40, and each shape (the tertiary on the surface of each droplet) is extracted from the extracted plurality of droplets. This is a step of measuring coordinate data at a plurality of positions on the original coordinate system.

  In addition, the correspondence table creation step S60 includes the tilt information at the position on the three-dimensional coordinate system of the surface of each droplet measured in the shape measurement step S50, and the two-dimensional coordinates corresponding to the position on the three-dimensional coordinate system. From the luminance information obtained in the imaging step S40 at a position on the system, the luminance information at a position on an arbitrary two-dimensional coordinate is used as an input value, and the inclination on the three-dimensional coordinate on the arbitrary two-dimensional coordinate is output. Is a step of creating a correspondence table.

  The droplet evaluation step S70 uses the luminance information about all droplets ejected from the evaluation target nozzle obtained in the imaging step S40 and the correspondence table created in the correspondence table creation step S60. This is a step of obtaining the volume or surface shape of all droplets ejected from the nozzle to be evaluated. In addition, based on the result, you may include the process of adjusting the voltage which should be applied to the piezoelectric actuator of each nozzle.

  The discharge / coating step S20 of the present embodiment corresponds to an example of the discharge step of the present invention, and the drying step S30 corresponds to an example of the reduced pressure drying step of the present invention.

  Next, each process mentioned above is further demonstrated.

  Here, the configuration of the substrate 100 in the substrate creation step S10 (see FIG. 2) and the setting condition of the contact angle α of the droplet with respect to the substrate 100 will be mainly described with reference to FIGS.

  FIG. 3 is a cross-sectional view showing the configuration of the substrate 100. The substrate 100 includes a support substrate 101 and a polymer film 102.

  FIG. 4 is a schematic diagram showing the relationship between the maximum angle θ incident on the objective lens 201 calculated from the numerical aperture of the objective lens 201 of the camera 601 (see FIG. 1) and the contact α of the droplet.

  For the support substrate 101, for example, glass can be used. The polymer film 102 is obtained by, for example, dissolving a resist material used for forming a light emitting layer of an organic EL display in an organic solvent, and applying and drying the support substrate 101 by spin coating or die coating. The material for the polymer film 102 is a photosensitive material made of polyimide or acrylic resin. And in this, you may contain the fluorine. The resin material containing fluorine is generally not particularly limited as long as it is highly transparent and has fluorine atoms in at least some of the polymer repeating units. Examples of the resin containing a fluorine compound include a fluorinated polyolefin resin, a fluorinated polyimide resin, a fluorinated polyacrylic resin, and the like. The film thickness is usually 0.1 to 3 μm, and particularly preferably 0.8 to 1.2 μm. Hereinafter, the case where a photosensitive material made of polyimide or acrylic resin is used as a polymer film as an example will be described.

  The polymer film 102 is prepared by dissolving a photosensitive material made of polyimide or acrylic resin in an organic solvent and applying a liquid to the support substrate 101 using a spin coat method or the like.

  By using a fluorine-containing polymer material as the material of the polymer film 102, the polymer film 102 has a water repellent function.

  Here, in the state where the fluorine film is formed on the surface, the water repellency may be too high, and a desired contact angle cannot be obtained after applying / drying the ink. , The water repellency of the substrate 100 can be controlled.

  The present inventors have determined that the contact angle α of the droplet 202 disposed on the polymer film 102 is the maximum angle θ of the objective lens determined by the numerical aperture (NA) of the objective lens 201 of the camera 601 used in the imaging process. And the following relational expression (see Expression 2) is preferably satisfied.

  Hereinafter, this relational expression will be described.

  4 is an objective lens of the camera 601 (see FIG. 1), 202 is a droplet after drying, and 100 is a substrate for sample preparation. Further, θ is the maximum angle of light incident on the objective lens 201 calculated from the lens NA, and is represented by the following expression (Expression 1).

θ = sin ⁻¹ (NA / n) (Equation 1)
Here, NA is the numerical aperture of the objective lens 201 of the camera 601 used for measuring the luminance information of the droplet, and n is the refractive index of the medium between the droplet and the objective lens 201.

  When the contact angle between the droplet after drying and the substrate 100 is defined as α, it is preferable that the contact angle α and the maximum angle θ are equal. The relationship between the contact angle α and the maximum angle θ of the objective lens 201 is as follows: Whether it is too large or too small with respect to the maximum angle θ, an error occurs when the inclination is obtained from the luminance information and the volume of the droplet or the surface shape of the droplet is obtained.

  However, in reality, it is difficult to strictly control the contact angle α of the liquid droplets, so that the desired measurement accuracy can be obtained by keeping the contact angle α within the range of the following equation (Equation 2). I understood.

1/5 × θ ≦ α ≦ 3 × θ (Equation 2)
Where θ = sin ⁻¹ (NA / n), NA is the numerical aperture of the lens, and n is the refractive index of the medium between the droplet and the objective lens.

  Hereinafter, the grounds for the lower limit and the upper limit of the contact angle α shown in (Formula 2) will be described with reference to FIGS. 5 and 6.

  In FIG. 5 and FIG. 6, for the sake of simplicity of explanation, the droplet height, the droplet inclination, and the image in the cross-sectional shape of the droplet when the droplet is cut in the XZ plane passing through the origin. The luminance will be described. The droplet height, the droplet inclination, and the number of cross-sectional shapes of the droplet obtained by cutting one droplet many times by a large number of planes passing through the origin and the Z axis. The same explanation can be applied to the image luminance.

  First, the lower limit of the contact angle α will be described with reference to FIG. FIG. 5 is a graph describing the droplet height, inclination, and brightness when the maximum droplet angle is α = θ and when α = 1/5 × θ. (A) is the droplet height. , (B) represents the droplet inclination, and (c) represents the image luminance.

  In the droplet inclination graph of FIG. 5B, the droplet inclination graph 801a with α = θ can measure up to the maximum inclination of the droplet because the maximum droplet angle is equal to the measurable angle θ of the lens. The luminance width i of the image luminance graph 802a in (c) is a value using, for example, about 90% of the luminance gradation k on the substrate plane. On the other hand, in the graph of α = 1/5 × θ, the maximum angle is ± 1/5 × θ in the (b) droplet inclination graph 811. Therefore, the luminance of the droplet luminance graph 812 in (c). The width j is a luminance difference of about 10% of k, for example. Here, in order to identify a droplet using image recognition, a luminance difference of about 10% is generally required with respect to the average value of the image luminance. Becomes difficult. That is, setting the contact angle α at the radial position on the X-axis of the droplet to be 1/5 × θ sets the minimum contact angle α at which the camera 601 can recognize the droplet on the substrate 100. Means to set.

  Next, the upper limit of the contact angle α will be described with reference to FIG. FIG. 6 is a graph describing the droplet height, inclination, and luminance when the maximum droplet angle is α = θ and when α = 3 × θ. (A) is the droplet height, ( b) represents the droplet inclination, and (c) represents the image luminance.

  In the droplet inclination graph of FIG. 6B, the droplet inclination graph 901 with α = θ can measure up to the maximum inclination of the droplet because the maximum droplet angle is equal to the measurable angle θ of the lens. Therefore, the droplet luminance graph 902 in (c) is information reflecting the shape up to the outer periphery of the droplet.

  On the other hand, in the graph of α = 3 × θ, the maximum angle is ± 3θ in the (b) droplet inclination graph 911, but it can only be measured up to the measurable angle θ of the lens. The luminance information of the portion where the inclination exceeds θ as in the luminance graph 912 is not luminance information reflecting the droplet shape but takes a certain value, for example.

  At this time, if the diameter of the droplet is D and the diameter of the droplet within the range of θ is d, then d = 1/2 × D when the contact angle α = 3 × θ. The inventors have found.

  In other words, the upper limit 3 × θ of the contact angle α is determined so that the camera 601 determines a portion of a droplet in a range at least half of the radius of the droplet on the substrate 100 (in the range of ¼ in the area on the XY plane). If it can be recognized, it is possible to determine the volume of the portion of the droplet in at least half of that range, so even if the total volume of one droplet is not determined, compared to the conventional method of measuring the area of the droplet The inventors of the present application have found that high measurement accuracy can be maintained.

  As described above, the contact angle α preferably satisfies the relationship of the above (formula 2), and more preferably, the contact angle α is adjusted so that the contact angle α matches the maximum angle θ.

  Therefore, in the first embodiment, the contact angle α between the droplet 202 and the substrate 100 is made to coincide with the maximum angle θ of light incident on the objective lens 201 calculated from the numerical aperture (NA) of the objective lens 201. Thus, in order to adjust the contact angle α, the contact angle α is given by the following equation (Equation 3).

α = θ = sin ⁻¹ (NA / n) (Equation 3)
According to the above (Equation 3), for example, when a lens with NA = 0.1 is used, if the medium between the objective lens and the droplet is air (0 ° C., 1 atm), the refractive index n is 1 .000292, the contact angle is 0.1 rad.

  Next, with reference to FIGS. 7 to 9, the description will focus on the creation of the volumetric droplet sample 301 ejected from all the nozzles to be evaluated in the ejection / application step S <b> 20 (see FIG. 2). .

  FIG. 7 is a schematic diagram showing a droplet application pattern of a volume measurement droplet sample used in the imaging step S40 and the shape measurement step S50 of the droplet measurement method according to the first embodiment. In FIG. 7, 301 is a volumetric droplet sample, 302 is a dummy droplet for maintaining a constant atmosphere when the volumetric droplet sample is dried, and 303 is a substrate for sample preparation. Note that the substrate 303 for sample preparation has basically the same configuration as the substrate 100 described in FIG.

  The dummy droplet 302 has a role of maintaining a constant solvent atmosphere of the volumetric droplet sample 301 during drying and maintaining a contact angle α of the volumetric droplet sample 301 within a certain range.

  Here, the dummy droplets 302 may be disposed so as to surround a plurality of volume measurement droplet samples 301, or may be disposed so as to surround individual volume measurement droplet samples 301. The number of dummy droplets 302 varies depending on the solvent of the ink used. For example, when the ink solvent is anisole, the outer periphery of the volume measurement droplet sample 301 is surrounded by dummy droplets of about 1 to 10 rounds. In this embodiment, two rounds of dummy droplets are arranged (see FIG. 7).

  In addition, it is good also as a structure which arrange | positions the dummy droplet which surrounds the outer periphery of the droplet sample 301 for volume measurement by one round as shown in FIG.

  In order to keep the solvent atmosphere constant, the solvent atmosphere may be adjusted by increasing or decreasing the number of ejections of ink used for one dummy droplet.

  In addition, the solvent atmosphere may be adjusted by changing the interval between the droplets for volumetric samples as shown in FIG. According to this configuration, an arbitrary solvent atmosphere can be realized as intended.

  FIG. 9 is a schematic front schematic diagram showing a volume measurement pattern when the droplets are sufficiently separated. Reference numeral 401 in FIG. 9 denotes a volume measurement droplet sample, reference numeral 402 denotes a solvent atmosphere volatilized from the droplet 401, and reference numeral 403 denotes a sample preparation substrate. The sample preparation substrate 403 has basically the same configuration as the substrate 100 described in FIG.

  As described above, all the volume measurement droplet samples 301, which are generated in the discharge / application step S20 (see FIG. 2) and discharged from all the nozzles to be evaluated, are the same number as all the nozzles. In step S40, the imaging target is selected, and in the shape measuring step S50, a part of the volumetric droplet sample 301 is set as the measuring target.

  Next, the drying step S30 (see FIG. 2) will be described with reference to FIGS.

  In the drying step S30, depending on the physical properties of the solvent of the ink to be used, for example, when the solvent is anisole, the ink is dried in a temperature range of 23 ° C. or more and 60 ° C. or less and in a reduced pressure atmosphere.

  By drying in the above-mentioned temperature range and in a reduced-pressure atmosphere, for example, even when the ink has a boiling point of 100 ° C. or higher as in the case where the solvent is anisole, drying can be performed within a practical time range.

  FIG. 10 is a graph showing the relationship between the apex height and diameter of the droplet in the cross section AB in FIG.

  The one end side region 501 and the other end side region 502 in FIG. 10 are mainly dummy applied to the outer periphery of a plurality of volumetric droplet samples 301 (see FIG. 7) applied on the substrate 303 (see FIG. 7). This is a region representing the relationship between the apex height and diameter of the droplet 302 (see FIG. 7), and the central region 503 is the apex height and diameter of the central portion of the plurality of volumetric droplet samples 301 applied on the substrate 303. This area represents the relationship.

  As can be seen from FIG. 10, in the dummy droplet 302 in the one end side region 501 and the other end side region 502 of the outer peripheral portion, the droplet apex height and diameter are greatly changed, whereas the volume measurement in the central region 503 is performed. It can be seen that in the liquid droplet sample 301, the height and diameter of the liquid droplet are more stable than those of the dummy liquid droplet 302 at the outer periphery.

  This is because the liquid droplets in the central region 503 are surrounded by the liquid droplets as shown in FIG. 7, so that the solvent atmosphere during drying is stabilized and dried over time. It is considered that the dummy droplets 302 in the one end side region 501 and the other end side region 502 have no droplets around them, so that the solvent atmosphere at the time of drying tends to change and the drying progressed rapidly.

  From the above, in order to stabilize the shape of the volume measuring droplet sample 301, the dummy droplet 302 is necessary.

  Next, the drying speed and the droplet shape will be described.

  FIG. 11A and FIG. 11B are schematic diagrams showing changes in droplet shape when drying is early and when drying is slow.

FIG. 11A is a schematic diagram showing the shape change of the droplet 801 that is dried quickly, and FIG. 11B is a schematic diagram showing the shape change of the droplet 802 that is dried quickly.
Since the droplet 801 that dries quickly shrinks in the height direction faster than the droplet shrinks in the diameter direction, a droplet having a large diameter and a low height is formed. The contact angle becomes low (small).

  On the other hand, the slow-drying droplet 802 has a low drying speed, so that the droplet shrinks to the height diameter faster than the droplet shrinks in the height direction, and thus a droplet having a small diameter and a high height is formed. The contact angle with the substrate becomes high (large).

  In this embodiment, the dummy droplet 302 is formed around the volume measurement droplet sample 301 so that the drying of the entire sample is suppressed, and the contact angle with the substrate is reduced by drying in a reduced-pressure atmosphere. This makes it possible to create low droplets.

  Next, the imaging mechanism 20 used in the imaging step S40 (FIG. 2) will be described with reference to FIG.

  The droplet discharge device 50 according to the present embodiment includes the imaging mechanism 20 as described with reference to FIG.

  FIG. 12 is a diagram schematically showing the overall configuration of the imaging mechanism 20 in the embodiment of the present invention.

  The imaging mechanism 20 includes a light source 600, a camera 601, a lens mechanism 602, a jig 603 that holds the camera 601 and the lens mechanism 602, a drive mechanism 605 that drives them along the scanning axis 604, and for focus adjustment. The Z-direction drive mechanism 606 is provided.

  The camera 601 and the lens mechanism 602 capture an image of the volumetric droplet sample 301 applied to the substrate 100 while moving along the direction of the scanning axis 604. The image data of the droplet sample is sent to the correspondence table creation unit 120 and the volume calculation unit 130 provided in the control unit 12.

  In addition, it is good also as a structure which adjusts by an autofocus at any time using the height sensor 607 and the Z direction drive mechanism 606 which were attached to the jig | tool 603. FIG.

  According to this configuration, the influence of the waviness of the glass surface of the substrate 100 can be removed.

  In order to simplify the operation, the focus may be adjusted using the Z-direction drive mechanism 606 at the start of imaging, and then imaging may be performed with the Z direction fixed.

  The camera 601 may be an area sensor or a line sensor. In this embodiment, a camera having a line sensor is used. The number of pixels and the pixel size may be selected according to the object to be imaged. In this embodiment, the number of pixels in the width direction is set to 4096 and the pixel size is set to 2 μm.

  The scanning resolution of the line sensor is obtained from the traveling speed of the camera obtained by calculating back from the required tact of the equipment. The speed of the traveling shaft is preferably 10 mm / s to 200 mm / s, and in this embodiment, it is set to 100 mm / s.

  The magnification and NA of the lens mechanism 602 are selected according to the shape of the imaging target droplet. In the present embodiment, a lens having a magnification of 5 times and an NA of about 0.1 is used.

  It is desirable to use a telecentric lens and relatively reduce the influence of focus.

  In order to avoid the influence of the optical axis tilt, it is preferable to use a coaxial epi-illumination lens.

  Next, a droplet evaluation step S70 for calculating the volume of each droplet using the droplet image data obtained in the imaging step S40, a shape measurement step S50, and a correspondence table creation step S60 will be described with reference to FIGS. This will be described with reference to FIG.

  Here, FIG. 13 is a flowchart for explaining the droplet evaluation step S70, and FIGS. 14A to 14E are diagrams for explaining a method of creating a correspondence table.

  Before describing the droplet evaluation step S70, the shape measurement step S50 and the correspondence table creation step S60 will be described mainly with reference to FIGS. 14 (a) to 14 (e).

  First, the shape measuring step S50 is a step of extracting a droplet at a predetermined position from all the droplets to be imaged (evaluated) in the imaging step S40 and measuring the shape of the extracted droplet. Yes (see FIG. 2). That is, in this embodiment, the position coordinate data (x, y, z) on the three-dimensional coordinate system (XYZ coordinate system) of the surface of the droplet is used as a known droplet shape measuring device (not shown). ) To measure.

  Specifically, one or a plurality of droplets are extracted from a plurality of droplets applied to the substrate 303, and the droplet profile is measured using a known droplet shape measuring apparatus.

  Here, for each of the extracted droplets, the surface of the substrate 303 is an XY two-dimensional plane, and the vertex of the droplet is the origin of the XY two-dimensional plane in plan view. The direction of the axis represents the height of the droplet.

  FIG. 14A shows the “distance in the X-axis direction from the droplet center (origin)” on the surface of the droplet and the “Z-axis direction” when the droplet is cut along the XZ plane passing through the origin. Is a curve showing a relationship of “height”, and this curve is one profile of a droplet. Here, in order to simplify the description, the description will be made based on one profile of a droplet shown in FIG. 14A, but in reality, one liquid is formed by many planes passing through the origin and the Z axis. The shape of the droplet is obtained from a large number of profiles of the droplet obtained by cutting the droplet many times. This curve may be expressed as an approximate function by a polynomial function or a trigonometric function.

  Note that the larger the number of droplets extracted in the shape measurement step S50, the better the droplet volume measurement accuracy. However, since the measurement time becomes longer, the droplet sample 301 (FIG. 7, FIG. It is desirable to extract one droplet for every 5 to 100,000 droplets (see 8). As an extraction method, it is preferable to extract based on the arrangement information of the droplets ejected onto the printing object 1 or based on the arrangement information of the droplet ejection module head 10.

  Note that a droplet to be extracted may be determined with reference to a droplet shape such as a diameter obtained from image information. According to this configuration, since the correspondence table can be properly used according to the shape of the droplet, it is possible to suppress the influence of errors due to the difference between the droplet used for the correspondence table creation and the shape of the droplet to be evaluated. Can do.

  Further, the above-described known droplet shape measuring device is desirably one that can accurately measure the shape even if it takes a long time to measure. For example, a measuring device based on the principle of optical interference or the principle of confocal may be used. In the present embodiment, a measuring instrument using optical interference is used.

  Further, the droplet shape measuring device may be mounted on the droplet discharge device 50, or may not be mounted on the droplet discharge device 50 but may be installed alone outside the device.

  Next, returning to FIG. 14 again, the correspondence table creation step S60 will be described.

  The correspondence table creation step S60 obtains the inclination at the position of the surface of the droplet on the three-dimensional coordinate system from the position coordinate data (x, y, z) based on each profile measured in the shape measurement step S50. A correspondence table showing a correspondence relationship between the obtained inclination and the luminance ratio at the position on the two-dimensional coordinate system corresponding to the position (this luminance ratio is obtained from the luminance data of the droplet obtained in the imaging step S40). This is a process of creating (see FIG. 2). In the present embodiment, the correspondence table is created by the correspondence table creation unit 120 (see FIG. 1).

  Specifically, the relationship between the “distance in the X-axis direction from the droplet center (origin)” on the surface of the droplet measured in the shape measurement step S50 and the “height in the Z-axis direction” at that position is shown. By differentiating the curve (see FIG. 14A), as shown in FIG. 14B, the relationship between the “distance in the X-axis direction from the center of the droplet (origin)” and the “tilt” at that position is obtained. I want.

  Next, a plurality of pixels (corresponding to each pixel of the CCD element of the camera 601) constituting the image of each droplet in all droplets ejected from all the nozzles to be evaluated obtained in the imaging step S40. From the luminance information of each pixel (for example, gradation level 0 to gradation level 255), a correspondence relationship between “distance in the X-axis direction from the droplet center (origin)” and “luminance” at that position is created ( Further, a correspondence relationship between the “distance in the X-axis direction from the center of the droplet (origin)” and the “luminance ratio” at that position is created (see FIG. 14D).

  14C and 14D, the droplets extracted in the shape measurement step S50 out of the images of all the droplets ejected from all the nozzles to be evaluated. The same droplet image is extracted.

  Here, the “luminance ratio” is a value obtained by dividing the luminance of each pixel by the luminance (reference luminance) at the reference position of the “image for each droplet” cut out for each droplet.

  Note that the reference luminance is preferably the maximum value of the in-drop luminance, and it is desirable to calculate the maximum value after performing smoothing processing in order to reduce variation.

  In order to reduce variation, the luminance obtained by averaging the luminance of the surface of the substrate 303 having a large area may be used as the reference luminance.

  By using the luminance ratio instead of the luminance as in this configuration, it is possible to reduce the influence of the luminance information change due to variations in illumination, the difference in reflectance of the print object, and the like.

  Next, the relationship between the “distance in the X-axis direction from the droplet center (origin)” shown in FIG. 14B and the “tilt” at that position, and the “liquid” shown in FIG. Based on the relationship between the “distance from the drop center (origin)” and the “brightness ratio” at that position, a “brightness ratio-slope” correspondence table is created (see FIG. 14E).

  Similarly, for each of the extracted droplets, a correspondence relationship between the “distance from the droplet center (origin)” and the “luminance ratio” at that position is created, and all of the created droplets are also created. The “brightness ratio-slope” correspondence table may be created by averaging the correspondence relationships.

  Note that the curve shown in FIG. 14E may be represented as an approximate function by a polynomial function or a trigonometric function.

  In these embodiments, description has been made based on one profile of a droplet with reference to FIG. 14, but it is obtained by cutting one droplet many times by a large number of planes passing through the origin and the Z axis. A “luminance ratio-slope” correspondence table may be created using a number of profiles of the droplets to be generated.

  The “brightness ratio-slope” correspondence table of the present embodiment is an example of the correspondence table of the present invention.

Note that the correspondence table described above (see FIG. 14E) may be theoretically created from a light reflection model. However, since the physical properties and shape of the droplet are unstable, the light reflectance is low. When it becomes unclear, it is preferable to create the correspondence table using the method described with reference to FIGS. 14 (a) to 14 (e).

  The above is the description of the shape measurement step S50 and the correspondence table creation step S60. Next, the droplet evaluation step S70 of FIG. 13 will be described. In the present embodiment, the droplet evaluation step is performed in the volume calculation unit 130 (see FIG. 1).

  First, in step S71, the position of each droplet was identified from the images of all droplets ejected from all nozzles to be evaluated, which were imaged in imaging step S40, and each droplet was cut out. Create an image for each droplet.

  In addition, as a specifying method for specifying the position of each droplet from the image, a position specifying method in known image processing was used.

  Next, using the “image for each droplet” obtained in step S71, the luminance ratio is obtained from the luminance information of the image in order for each droplet, and the “luminance ratio-slope” correspondence table (FIG. 14 (e)). )) Is used to calculate all the inclinations at the pixel positions of the pixels included in the plurality of pixels corresponding to the image of one droplet (see step S72 in FIG. 13).

  Next, with respect to an image of one droplet, the height (provisional value) in the Z direction of each pixel position is calculated using all the inclination information obtained at step S72 (see step S73). .

  Hereinafter, a method for calculating the height in the Z direction at each pixel position from the inclination at each pixel position will be described with reference to FIGS. 15 and 16.

  For convenience of explanation, the case of only the fourth quadrant will be described, but the identification is performed in the same way in the first to third quadrants.

  FIG. 15 is a diagram for explaining a method of converting the inclination of the surface of one droplet on the three-dimensional coordinate system as a vector component in the two-dimensional coordinate system, and FIG. 16 is a diagram illustrating one droplet. It is a figure explaining the method of calculating | requiring the height in the position on the three-dimensional coordinate system of the surface.

  First, as shown in FIG. 15, the slope kp at the position P on the three-dimensional coordinate system of the surface of one droplet corresponding to each pixel position of one droplet is a vector toward the vertex of the droplet. Considered as a scalar value, it is decomposed into an X component kx and a Y component ky. Next, an arbitrary height (H0) is once given to a pixel position (corresponding to the origin position (0, 0) in FIG. 15) in the image for each droplet including the droplet vertex.

  It should be noted that the pixel position including the droplet vertex is preferably a pixel position where the luminance is maximum in the image for each droplet.

  In order to prevent erroneous recognition due to noise, the pixel position where the luminance is maximum in the image for each droplet after smoothing using an averaging filter, a median filter, a Gaussian filter, or the like may be used.

  It should be noted that the luminance centroid may be obtained in each droplet image, and the luminance centroid may be defined as the droplet vertex.

  Next, a method for obtaining the height of the surface of one droplet at a position on the three-dimensional coordinate system will be described with reference to FIG.

  The height of an arbitrary pixel position B on the X axis other than the pixel position A including the droplet vertex (corresponding to the origin of FIG. 16) is the pixel position adjacent to the pixel position B in the negative direction of the X direction. From the height, to the X component inclination of the pixel position B, to the X component inclination of the pixel position adjacent to the pixel position B in the negative direction of the X direction, or to the average value thereof, the pixel position B and the pixel position B Can be calculated by adding a value obtained by multiplying the distance between adjacent pixel positions in the negative X direction.

  Similarly, the height of an arbitrary pixel position C on the Y axis other than the pixel position A including the droplet vertex (corresponding to the origin of FIG. 16) is in the positive Y direction with respect to the pixel position C. From the height of the adjacent pixel position, to the Y component inclination of the pixel position C, to the Y component inclination of the pixel position adjacent to the pixel position C in the positive Y direction, or to the average value thereof, the pixel position It can be calculated by adding a value obtained by multiplying C and the pixel position C by the distance between pixel positions adjacent in the positive direction of the Y direction.

  Note that when the height of the pixel position A including the droplet vertex or the pixel position D other than the pixel position (B, C) on the X axis or the Y axis is obtained, the pixel position D is negative in the X direction. It can be calculated in the same manner as in the above method using the height and inclination of the pixels adjacent in the direction and / or the pixels adjacent in the positive Y direction.

  Next, the droplet diameter is calculated using the luminance information of the image (see step S74).

  The calculation method creates a correspondence between the brightness and the distance from the center of the droplet (see FIGS. 14C and 14D), and calculates the distance from the center of the droplet when the brightness is the minimum value. It is good to derive it.

  In addition, in order to suppress the influence of noise, the function or scatter diagram showing the correspondence between the brightness and the distance from the droplet center is differentiated once, and the value of the function or scatter diagram becomes the extreme value from the droplet center. It may be derived based on the distance.

  In calculating the droplet diameter, information on all pixels may be used, but for simplification, pixel information in the X-axis direction and / or the Y-axis direction may be used.

  Next, the height He (temporary value) at the outer peripheral portion is calculated using the droplet diameter obtained in step S74 and the height (temporary value) at each pixel position obtained in step S73. The height He at the outer peripheral portion is preferably obtained as an average of the heights at the pixel positions within a range of a certain distance e from the droplet radius determined from the droplet diameter.

  Note that the height He at the outer peripheral portion may be calculated using height information at all pixel positions of pixels existing within a certain distance e from the droplet radius. Pixel information only in the direction and / or in the Y-axis direction may be used.

  Here, from the height (provisional value) at each pixel position obtained in step S73, the height at the outer peripheral portion is calculated so that the height (temporary value) He at the outer peripheral portion obtained as described above becomes zero. By subtracting (temporary value) He, an offset is given to the height at all pixel positions, and the height (true value) at each pixel position is calculated.

  For example, when the height (provisional value) at the pixel position A is HA0 and the height (provisional value) He at the outer peripheral portion is He0, the height (true value) HA at the pixel position A is expressed as 4).

HA = HA0−He0 (Equation 4)
Next, for the pixel position within the range of the diameter obtained in step S74, the product V0 of the height HA (true value) at each pixel position stopped in step S75 and the area S0 of the pixel corresponding to each pixel position. By adding all (see FIG. 17) for one droplet 700, the volume V of the one droplet can be obtained (see step S76). Here, FIG. 17 is a schematic diagram of the droplet 700 for explaining the calculation in step S76.

  Next, in step S77, it is determined whether or not the calculation of the volume V of the droplet has been completed for all droplets. If it is determined that the calculation has not been completed, the process returns to immediately before step S71, and the above-described step S72. Step S76 is repeated, and if it is determined that the process is completed, the process proceeds to Step S78, and the volume of all droplets of the nozzle that has been evaluated in Step S76 is obtained.

  The amount of variation between the determined volume of the droplet and the predetermined volume of the droplet of the nozzle is determined, and the applied voltage to the piezoelectric actuator corresponding to each nozzle is adjusted so as to be within a predetermined range. Is good.

  As described above, from the correspondence table showing the correspondence between the inclination of the surface of the droplet on the position on the three-dimensional coordinate system and the luminance information corresponding to the position, any of the nozzles ejected from at least some of the nozzles of the head An inclination of an arbitrary portion of an arbitrary droplet can be derived from luminance information at an arbitrary portion of the droplet.

  Further, according to the configuration described above, it is possible to identify the droplet discharge amount at a high speed when the shape of the droplet applied to the print object is not greatly different.

  In addition, according to these configurations, the present invention can be applied even when the droplet shape is not point-symmetric, and is used for measuring the surface shape of the droplet in addition to the measurement of the discharge amount (volume of the droplet). be able to.

  In the ejection amount measurement method according to this configuration, the amount of light reflection is an important factor that determines the measurement accuracy. For example, if the reflectivity of the stage surface on which the measurement object is placed is uneven, the measurement accuracy deteriorates. Invite.

  Therefore, in order to eliminate unevenness in the reflectivity of the stage surface on which the measurement object is placed, the stage surface is imaged without placing the measurement object and the measurement object is placed separately from imaging the measurement object. It is desirable to measure the volume by the above method after creating an image obtained by subtracting the image brightness captured without placing the measurement object from the captured image brightness.

  In the ejection amount measuring method according to this configuration, when the positional relationship between the measurement object and the lens is different, the measured volume may be different due to the influence of lens distortion even if the target droplet is the same. Further, the positional relationship between the object to be measured and the lens and the relationship between the volumes to be measured are different depending on the slight difference in the camera mounting angle.

  Therefore, using a master sample or the like in advance, the positional relationship between the object to be measured and the lens, and the relationship between the volume to be measured are derived. It is desirable to use it.

  Next, the range of the number N of nozzles in which the droplet measuring method described in the above embodiment exhibits a remarkable effect as compared with the conventional method is shown in the following formula (Formula 5).

60 ≦ N ≦ 1,200,000 (Equation 5)
Below, the grounds for the lower and upper limits of (Formula 5) will be described.

  The lower limit is as follows.

  When comparing the measurement times of the conventional droplet measurement method using optical interference and the droplet measurement method of the present embodiment, the droplet measurement method of the present embodiment is equivalent to the conventional measurement device. To extract a predetermined number of droplets from a volumetric droplet sample discharged from all nozzles to be evaluated, measure the shape, and create a “brightness ratio-slope” correspondence table. Therefore, preparation is required for measurement.

  Therefore, for example, if only one droplet is measured, the conventional method is faster, but the droplet measurement method of the present embodiment has a faster measurement time per droplet than the conventional method. Over a certain number of drops, the total measurement time is shorter than in the conventional method.

  Therefore, the measurement time F according to the conventional method can be expressed by the following formula (Formula 6).

F = A + B × N (6)
Here, A represents the preparation time of the conventional method, B represents the measurement time per droplet of the conventional method, and N represents the number of droplets to be measured (evaluation target), that is, the number of nozzles.

  Next, the measurement time G according to the method of the present embodiment can be expressed by the following formula (formula 7).

G = A ′ + D × N + B × (N / E + 1) (Equation 7)
Here, A ′ is the preparation time of the method of the present embodiment, D is the measurement time per droplet of the method of the present embodiment, and E is the time when measuring the shape of the droplet using the conventional method. Let us denote the interval between droplets to be extracted.

  As specific values of the above variables, A = 30 sec, B = 1 sec, A ′ = 60 sec, D = 0.001 sec, E = 100 drops, and these values are expressed by the above (formula 6) and (formula 7). Substituting for each of N = 60, the measurement time F according to the conventional method and the measurement time G according to the present embodiment are both approximately 90 seconds, and if the number of droplets (nozzle number) is larger than that, Since the measurement time G according to the present embodiment is shorter than the measurement time F according to the conventional method, the lower limit can be set to 60 pieces.

  On the other hand, the upper limit is as follows.

  If the number of measurement objects is significantly increased from 60, the measurement time becomes long and the measurement becomes practically difficult.

  Therefore, even if the method of the present embodiment is used, for example, when the number of nozzles for which the measurement time per color is about 4 hours, the measurement time is 12 hours for three colors of RGB. The volume adjustment of the droplet is performed by adjusting the voltage change (see step S78 in FIG. 14) and the volume measurement (see steps S71 to S76 in FIG. 14) two to three times. Is 24 hours to 36 hours, and is practically the lower limit of a value that is difficult to achieve in order to ensure the operating rate and the like.

  Therefore, when the number of nozzles for which the measurement time G per color is about 4 hours is obtained, it is approximately 1,200,000, so this is set as the upper limit.

  From the above, when the number of nozzles is 60 or more and 100,000 or less, according to the droplet measuring method of the present embodiment, the measurement accuracy can be ensured in a shorter measuring time than the conventional method. .

  In the above embodiment, as the droplet measuring method of the present invention, a case has been described in which droplets to be evaluated are ejected and some of the droplets are used to create a correspondence table (see FIG. 2). ).

  However, the present invention is not limited to this, and, for example, as an example of another droplet measuring method of the present invention, the method shown in FIG. FIG. 18 is a schematic flowchart showing the second droplet measuring method.

  18, the first step SS100 is a flowchart showing the droplet measuring method shown in FIG. 2. In each step, the same step as in FIG. In FIG. 18, another substrate creation step S110, another ejection / application step S120, another drying step S130, and another imaging step S140 are the substrate creation step S10 and ejection / application step S20 described in FIG. This is basically the same as the drying step S30 and the imaging step S40. 18 is basically the same as the droplet evaluation step S70 described in FIG. 2, except that the droplet is evaluated using the correspondence table created in the correspondence table creation S60. Is the same.

  In the second droplet measuring method shown in FIG. 18, for example, the first step SS100 (including S10 to S70) is first performed on the line head 9 in FIG. When performing a simple measurement every week, the measurement is performed according to steps S110 to S170 using the correspondence table (see S60) created in the first measurement performed one week ago. In the periodic measurement performed every month, the measurement is performed again according to the first step SS100 (including S10 to S70).

  According to this configuration, since it is not necessary to create a correspondence table for each measurement, it is possible to perform measurement more efficiently, in a short time, and to ensure measurement accuracy.

  Further, in the above embodiment, as the droplet measuring method of the present invention, a case has been described in which droplets to be evaluated are ejected and some of the droplets are used to create a correspondence table (see FIG. 2). ).

  However, the present invention is not limited to this. For example, as an example of another droplet measuring method of the present invention, as shown in FIG. 19, a droplet is ejected only to create a correspondence table, and a droplet to be evaluated is ejected. The structure which provided the process to perform as another process may be sufficient. FIG. 19 is a schematic flowchart showing a third droplet measurement method. In FIG. 19, the same steps as those in FIG.

  The correspondence table creation ejection / application step S220 in FIG. 19 is the same as the ejection / application in FIG. 2 except that droplets are ejected from a part of the nozzles to be evaluated, which are set for correspondence table creation. This is basically the same as step S20. Here, the method of setting some of the nozzles is the same as the “how to extract” described for the extraction of droplets in the shape measurement step S50 of the first embodiment. Further, the shape measuring step S250 of FIG. 19 is the same as that of FIG. 2 except that the shape is measured for all the droplets ejected from some of the preset nozzles in the correspondence table creating ejection / application step S220. This is basically the same as the shape measurement step S50. Further, the correspondence table creation step S260 in FIG. 19 creates a correspondence table using all the droplets ejected from some of the nozzles set in advance in the correspondence table creation ejection / application step S220, This is basically the same as the correspondence table creation step S60 of FIG. Further, the droplet evaluation step S370 is basically the same as the droplet evaluation step S70 described in FIG. 2 except that the droplet is evaluated using the correspondence table created in the correspondence table creation step S260. . Here, the droplet used in the correspondence table creation step S220 and the droplet evaluated in the droplet evaluation step S370 are different droplets, but a line head having a nozzle that ejects these droplets ( The line head 9 in FIG. 1) is the same. With this configuration, the same effect as the droplet measuring method of the above embodiment is exhibited.

  Further, in FIG. 19, the first work process from the substrate creation process S10 to the correspondence table creation process S260 through the correspondence table creation ejection / application process S220, shown on the left side of the figure, and the right side of FIG. The case where the second work process from the substrate creation process S10 through the discharge / application process S20 to the droplet evaluation process S370 proceeds in parallel has been described. However, the present invention is not limited to this. After completion of the creation step S260, the configuration may proceed to the second operation step from the substrate creation step S10 through the discharge / application step S20 to the droplet evaluation step S370 described on the right side of FIG. In short, on the assumption that droplets from the same line head are used, as long as the correspondence table creation step S260 is completed before proceeding to the droplet evaluation step S370, each step described on the left side in FIG. The steps described on the right may proceed in any order.

  In the third droplet measuring method shown in FIG. 19, the first work process described on the left side in FIG. 19 and the second work process described on the right side in FIG. However, the present invention is not limited to this. For example, on the assumption that droplets from the same line head are used, the correspondence table creation step S260 is performed before proceeding to the droplet evaluation step S370. As long as it is completed, the first work process described on the left side in FIG. 19 and the second work process described on the right side in FIG. 19 may be performed in different places. Alternatively, it may be performed at different times, or may be performed by different working subjects.

  Further, in the third droplet measuring method shown in FIG. 19, in order to only create the correspondence table in the correspondence table creation ejection / application step S220, a part of all the nozzles to be evaluated is used. Different from the droplet measurement method of FIG. 2 in that the droplets are discharged and the droplets are discharged from all the nozzles to be evaluated in the discharge / application step S20. In the ejection / coating process S220, as in the ejection / coating process S20 of FIG. 2, droplets are ejected from all the nozzles to be evaluated, and the droplets ejected from all the nozzles in the correspondence table creating process S260. A configuration may be used in which some of the droplets are extracted and used to create the correspondence table.

  In the above-described embodiment (see FIG. 19), as an example of another droplet measuring method of the present invention, a step of discharging a droplet only to create a correspondence table and discharging a droplet to be evaluated The structure provided as a separate process has been described.

  However, the present invention is not limited to this, and, for example, as another example of the droplet measuring method of the present invention, the method shown in FIG. FIG. 20 is a schematic flowchart showing a fourth droplet measurement method.

  20, the second step SS200 is a flowchart showing the third droplet measurement method shown in FIG. 19. In each step, the same steps as those in FIG. In FIG. 20, another substrate creation step S410, another ejection / application step S420, another drying step S430, and another imaging step S440 are the substrate creation step S10 and ejection / application step S20 described in FIG. This is basically the same as the drying step S30 and the imaging step S40. 20 is basically the same as the droplet evaluation step S370 described with reference to FIG. 19 except that the droplet is evaluated using the correspondence table created in the correspondence table creation S260. Is the same.

  In the fourth droplet measuring method shown in FIG. 20, for example, the second step SS200 is first performed for the line head 9 of FIG. 1, and then, for the same line head 9, for example, simple measurement is performed every week. Is performed according to steps S410 to S470 using the correspondence table (see S260) created in the first measurement performed one week ago, and further, for example, periodic measurement performed every month Then, again, it is the structure which measures according to 2nd process SS200.

  According to this configuration, since it is not necessary to create a correspondence table for each measurement, it is possible to perform measurement more efficiently, in a short time, and to ensure measurement accuracy.

  In the above-described embodiment, the configuration including the drying step of drying the droplets on the substrate in the reduced pressure atmosphere in the reduced pressure chamber (not shown) has been described. However, the present invention is not limited to this, and for example, a decompression chamber may not be provided, and a configuration including a drying process for drying droplets on the substrate at atmospheric pressure may be used, or the drying process itself may be omitted.

  In the above embodiment, the case where the nozzles to be evaluated are all the nozzles of the line head 9 has been described. However, the present invention is not limited to this. For example, a part of the nozzles of the line head 9 may be the target of evaluation. good.

  Further, in the above-described embodiment, a case has been described in which the droplet evaluation process evaluates all of the droplets (except for the dummy droplets) ejected in the ejection / coating process. A configuration may be used in which only some of the droplets discharged in the coating process (excluding dummy droplets) are evaluated.

  In the above embodiment, the case where the contact angle α is adjusted so that the contact angle α between the droplet and the substrate coincides with the maximum angle θ of the objective lens (α = θ) is described, but the present invention is not limited thereto. For example, the contact angle α may not coincide with the maximum angle θ of the objective lens.

  In the present embodiment, the case where the contact angle α is adjusted so that the contact angle α between the droplet and the substrate coincides with the maximum angle θ of the objective lens in the correspondence table creation process (α = θ) has been described. However, the present invention is not limited to this. For example, even when the contact angle α is adjusted to the lower limit shown in (Expression 2) (that is, α = 1/5 × θ), it is the same as the case where α = θ described above. Then, a droplet profile is measured using a known droplet shape measuring apparatus (see graph 810 in FIG. 5A), and from the measured profile, the volume calculation unit 130 determines “droplet center (origin)”. The relationship between the “distance in the X-axis direction from” and the “tilt” at that position is obtained (see the droplet tilt graph 811 in FIG. 5B), and the luminance information of the droplet imaged using the camera 601 To “Distance in the X-axis direction from the droplet center (origin)” and its position (Refer to the droplet luminance graph 812 in FIG. 5C), and the “distance in the X-axis direction from the droplet center (origin)” and the “luminance” at that position. A correspondence relationship (not shown) with “ratio” can be created. The relationship between the “distance in the X-axis direction from the droplet center (origin)” and the “tilt” at that position shown in FIG. 5B (see the droplet tilt graph 811 in FIG. 5B). From the relationship between the “distance in the X-axis direction from the droplet center (origin)” and the “brightness ratio” at that position, a “brightness ratio-slope” correspondence table can be created as described above.

  In the present embodiment, the case where the contact angle α is adjusted so that the contact angle α between the droplet and the substrate coincides with the maximum angle θ of the objective lens in the correspondence table creation process (α = θ) has been described. However, not limited to this, for example, even when the contact angle α is adjusted to the upper limit shown in (Expression 2) (that is, α = 3 × θ), as in the case of α = θ described above, The droplet profile was measured using the droplet shape measuring apparatus (see graph 910 in FIG. 6A), and the volume calculation unit 130 calculated from the measured profile “from the droplet center (origin)”. The relationship between the “distance in the X-axis direction” and the “tilt” at that position is obtained (see the drop tilt graph 911 in FIG. 6B), and the brightness information of the droplet imaged using the camera 601 indicates “ The distance in the X-axis direction from the droplet center (origin) and its position A correspondence relationship with “luminance” is created (see the droplet luminance graph 912 in FIG. 6C), and “distance in the X-axis direction from the droplet center (origin)” and “luminance ratio at that position” "(Not shown) can be created. The relationship between the “distance in the X-axis direction from the droplet center (origin)” and the “tilt” at that position shown in FIG. 6B (see the droplet tilt graph 911 in FIG. 6B). From the relationship between the “distance in the X-axis direction from the droplet center (origin)” and the “brightness ratio” at that position, a “brightness ratio-slope” correspondence table can be created as described above. Note that, as described above, the droplet luminance graph 912 showing the correspondence between the “distance in the X-axis direction from the droplet center (origin)” and the “luminance” at the position shown in FIG. The luminance information of the portion exceeding θ is not luminance information reflecting the droplet shape, but takes a constant value, for example. Therefore, regarding the correspondence relationship between the “distance in the X-axis direction from the center of the droplet (origin)” and the “luminance ratio” at that position, the luminance ratio of the portion where the inclination exceeds θ reflects the droplet shape. Since not a luminance ratio but a constant value as described above, a “luminance ratio-slope” correspondence table is created within a range of ½ of the radius of the droplet from the droplet center.

However, the present invention is not limited to this, and, for example, as another example of the droplet measuring method of the present invention, the method shown in FIG. FIG. 21 is a schematic flowchart showing the fifth droplet measurement method.
In FIG. 21, the substrate creation step S10, the discharge / coating step S20, the drying step S30, and the imaging step S40 are basically the same as the steps described above.
The classification step S80 is a step of classifying all the droplets into a plurality of groups for each shape using the luminance information of the droplets imaged in the imaging step S40. The characteristics of the shapes to be classified will be described later.

  In the shape measurement step S50, at least one droplet is extracted for each group classified in the classification step S80, and each shape (three-dimensional on the surface of each droplet) is extracted from the extracted plurality of droplets. This is a step of measuring coordinate data at a plurality of positions on the coordinate system.

  In addition, the correspondence table creation step S60 includes the tilt information at the position on the three-dimensional coordinate system of the surface of each droplet measured in the shape measurement step S50, and the two-dimensional coordinates corresponding to the position on the three-dimensional coordinate system. From the luminance information obtained in the imaging step S40 at a position on the system, the luminance information at a position on an arbitrary two-dimensional coordinate is used as an input value, and the inclination on the three-dimensional coordinate on the arbitrary two-dimensional coordinate is output. Is a step of creating a correspondence table. The correspondence table is created for each group classified in the classification step S80.

Further, in the droplet evaluation step S70, the luminance information about all the droplets ejected from the evaluation target nozzle obtained in the imaging step S40 and the droplets created in the correspondence table creation step S60 are classified. This is a step of obtaining the volume or surface shape of each of the droplets ejected from the nozzle to be evaluated using the correspondence table applied to each group. In addition, based on the result, you may include the process of adjusting the voltage which should be applied to the piezoelectric actuator of each nozzle.

  According to these configurations, even when the shape of the droplet created in the discharge / coating step S20 is not uniform, the correspondence table is created for each similar droplet shape and the droplet measurement is performed. The effect of improving is demonstrated.

  In the classification step, it is preferable to use a ratio between the luminance near the top of the droplet and the luminance on the substrate around the droplet in order to discriminate the difference in droplet shape.

  Note that because these structures have different light refraction angles for different droplet shapes, the steep droplets have lower brightness near the top than the flat droplets. The inventors have found out.

  According to these configurations, it is possible to classify the droplet shapes using only the luminance information obtained from the imaging step S40.

  Further, by using the ratio with the luminance on the substrate in the vicinity of the droplet, it is possible to reduce the influence caused by variation in illumination intensity due to variation in illumination intensity, variation in distance between the lens and the droplet, or the like.

  In the classification step S80, in order to determine the difference in droplet shape, a ratio between the luminance near the top of the droplet and the luminance near the mist of the droplet may be used.

  According to these configurations, a larger contrast can be obtained as compared with the case of using the ratio with the luminance on the substrate in the vicinity of the droplets, so that shape classification with high accuracy is possible.

  In the classification step S80, in order to determine the difference in the droplet shape, the vertex in the image luminance in at least one cross-sectional shape passing through the vertex of the droplet at a right angle to the substrate on which the droplet is applied. You may use the distance from a vertex when a brightness | luminance falls only a fixed ratio with respect to a brightness | luminance.

  Even with these configurations, it is possible to classify the droplet shapes using only the luminance information obtained from the imaging step S40.

  Since these structures have different light refraction angles for different droplet shapes, steep droplets are perpendicular to the substrate on which the droplets are applied, compared to flat droplets. The inventors of the present application have found that the brightness gradient in the image brightness at at least one cross-sectional shape passing through the top of the droplet becomes steep.

  In addition, by using the distance from the vertex when the luminance decreases by a certain ratio with respect to the vertex luminance as a determination parameter, it is possible to reduce factors such as variations in illumination intensity.

  In order to obtain a relative value to the size of the droplet, the distance from the vertex when the luminance decreases by a certain ratio with respect to the vertex luminance may be a ratio with the diameter value of the droplet.

  According to the droplet measuring method and the droplet measuring system of the present invention, it is possible to measure the volume or shape of the applied droplet at a high speed and to ensure measurement accuracy, for example, color unevenness of a printing object, etc. Can be measured at high speed, and the inkjet apparatus can be calibrated at high speed.

  For this reason, for example, it is useful for the use of a droplet discharge printing apparatus for coating and forming an organic light emitting material in the manufacture of an organic EL display panel.

DESCRIPTION OF SYMBOLS 1 Print object 2 Head unit 3 Table 4 Leg part 5 Support part 6 Gantry 7 Support stand 8 Distribution tank 9 Line head 10 Droplet discharge module head 11 Stage 12 Control part 20 Imaging mechanism 50 Droplet discharge apparatus 100 Substrate 101 Support substrate 102 Polymer film 120 Corresponding table creation unit 130 Volume calculation unit 201 Objective lens 202 Droplet 301 Volume measurement droplet sample 302 Dummy droplet 303 Substrate 401 Droplet 403 Substrate 501 One end side region 502 Other end side region 503 Central region 600 Light source 601 Camera 602 Lens mechanism 603 Jig 604 Scan axis 605 Drive mechanism 606 Direction drive mechanism 607 Sensor 700 Droplet 801 Droplet 802 Droplet 801a, 810 Graph 802a, 811 Graph 812 Droplet luminance graph 901 Graph 902 Droplet luminance graph 910 Graph 911 Graph 912 Droplet luminance graph

Claims (13)

An ejection step of ejecting a plurality of droplets onto a substrate from at least some of the nozzles of the head;
An imaging step of imaging the droplet;
Based on the luminance information obtained in the imaging process for at least some of the droplets, the inclination of the surface of the droplet at a position on the three-dimensional coordinate system and the luminance information corresponding to the position A correspondence table creation process for creating a correspondence table representing a correspondence relationship with
Using the brightness information obtained in the imaging step and the correspondence table, a droplet evaluation step for obtaining a volume or a surface shape of the droplet,
A droplet measurement method comprising: An ejection step of ejecting a plurality of droplets onto a substrate from at least some of the nozzles of the head;
An imaging step of imaging the droplets ejected on the substrate in the ejection step;
A correspondence table representing the correspondence between the inclination of the surface of the droplet on the substrate prepared in advance on the three-dimensional coordinate system and the luminance information corresponding to the position; and the luminance information obtained in the imaging step; And a droplet evaluation step for determining the volume or surface shape of the droplet,
A droplet measurement method comprising: After the droplet evaluation step, another discharge step for newly discharging a plurality of droplets from at least some nozzles of the head onto the substrate;
Another imaging step of imaging the newly ejected droplet;
Using the correspondence table, another droplet evaluation step for determining the volume or surface shape of the newly ejected droplet;
The droplet measuring method according to claim 1 or 2, further comprising: 3. The droplet according to claim 1, wherein a contact angle α between the droplet and the substrate in the imaging step satisfies a relationship of the following equation with a maximum angle θ of incident light of a lens used in the imaging step. Measuring method.
1/5 × θ ≦ α ≦ 3 × θ
Where θ = sin−1 (NA / n), NA is the numerical aperture of the lens, and n is the refractive index of the medium between the droplet and the lens. A polymer film having water repellency is formed on the surface of the substrate,
The droplet measurement method according to claim 1, further comprising: a reduced-pressure drying step of drying the droplets on the substrate in a reduced-pressure atmosphere between the ejection step and the imaging step. The position of the surface of the droplet on the three-dimensional coordinate system is represented by XYZ coordinates,
The droplet measurement method according to claim 1 or 2, wherein the luminance information obtained in the imaging step is represented by XY plane coordinates on the XYZ coordinate system. An ejection step of ejecting a plurality of droplets onto a substrate from at least some of the nozzles of the head;
An imaging step of imaging the droplet;
A classification step of classifying the droplet shapes into a plurality of groups using the luminance information of the droplets obtained in the imaging step;
Correspondence table representing the correspondence between the inclination of the surface of the droplet at a position on the three-dimensional coordinate system and the luminance information corresponding to the position for at least some droplets from the group classified in the classification step The correspondence table creation process to create for each classified group,
A droplet evaluation step for determining the volume or surface shape of the droplet using the luminance information obtained in the imaging step and the correspondence table created for each classified group;
A droplet measurement method comprising:   The droplet measuring method according to claim 7, wherein, in the classification step, a ratio of the luminance near the top of the droplet and the luminance on the substrate around the droplet is used to determine a difference in droplet shape.   The droplet measuring method according to claim 7, wherein, in the classification step, a ratio between the luminance near the top of the droplet and the luminance near the mist of the droplet is used to determine a difference in droplet shape.   In the classification step, in order to determine the difference in droplet shape, the vertex luminance in the image luminance in at least one cross-sectional shape passing through the vertex of the droplet at a right angle to the substrate on which the droplet is applied. The droplet measurement method according to claim 7, wherein the distance from the apex when the luminance is reduced by a certain rate is used. A head having a plurality of nozzles for discharging droplets;
An imaging unit that images the plurality of droplets ejected from at least a part of the nozzles onto the substrate;
Based on the luminance information obtained by the imaging unit for at least some of the droplets, the inclination of the surface of the droplet at a position on a three-dimensional coordinate system and the luminance information corresponding to the position A correspondence table creation unit for creating a correspondence table representing a correspondence relationship with
Using the luminance information obtained by the imaging unit and the correspondence table created by the correspondence table creation unit, a droplet evaluation unit for determining the volume or surface shape of the droplet,
Droplet measurement system equipped with. A head having a plurality of nozzles for discharging droplets;
Based on the luminance information of a plurality of droplets on the substrate ejected from at least some of the nozzles of the head, the inclination of the surface of the droplet at a position on a three-dimensional coordinate system and the luminance information corresponding to the position A correspondence table creation unit for creating a correspondence table representing a correspondence relationship with
An imaging unit that images the plurality of droplets ejected from at least some of the nozzles onto the substrate;
Using the luminance information obtained by the imaging unit and the correspondence table created by the correspondence table creation unit, a droplet evaluation unit for determining the volume or surface shape of the droplet,
Droplet measurement system equipped with. A head unit that ejects a plurality of droplets from at least some of the nozzles on the substrate;
An imaging unit for imaging the droplet;
A classification unit that classifies droplet shapes into a plurality of groups using the luminance information of the droplets obtained in the imaging step;
A correspondence table representing a correspondence relationship between the inclination of the surface of the droplet on the three-dimensional coordinate system at the position on the three-dimensional coordinate system and the luminance information corresponding to the position for at least some of the droplets classified by the classification unit. A correspondence table creation unit that creates each classified group,
A droplet evaluation unit for determining a volume or a surface shape of the droplet using the luminance information obtained in the imaging unit and the correspondence table created for each classified group;
Droplet measurement system equipped with.

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