JP2018179966A - Liquid droplet measurement method and liquid droplet measuring apparatus, method for manufacturing device, and device manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid droplet measurement method and a liquid droplet measuring apparatus, a method for manufacturing a device, and a device manufacturing apparatus, in which luminance contrast is improved without changing the numerical aperture NA, etc. of a lens when sufficient luminance contrast cannot be obtained with only the amount of reflected light from the liquid droplet surface being measured.SOLUTION: A liquid droplet measuring apparatus is used, the apparatus comprising: a measurement table for holding a light permeable sample substrate and having a recess in the surface; an imaging unit for irradiating the sample substrate having had a liquid droplet formed on its surface with light and measuring reflected light from the sample substrate and the liquid droplet; and a measurement control unit for obtaining the cubic volume or surface shape of the liquid droplet on the basis of luminance information pertaining to the light quantity of the reflected light measured by the imaging unit. The thickness of the sample substrate is larger than the wavelength of the light and less than or equal to the focal distance of the liquid droplet.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a droplet measurement method, a droplet measurement device, a method of manufacturing a device, and a device of manufacturing a device.

  As a method of manufacturing devices such as color filters for liquid crystal displays and organic EL displays, for example, a liquid material containing a functional material is discharged as droplets from a plurality of nozzles by an inkjet method, and a film of functional material is printed on an object Panel manufacturing methods are known to form

  In this case, it is important to control the discharge amount of the droplet to a constant value by acquiring 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. . This is because if the discharge amount of the droplets is non-uniform, the film thickness of the functional material is different, which leads to the failure of the device. For example, in the case of a color filter or an organic EL display, the difference in film thickness is observed as color unevenness or luminance unevenness.

  There are the following methods to check the actual discharge amount from the nozzle. There is known a method in which ink is ejected / applied to a substrate, and the inclination at that point is calculated optically from the change in brightness of each point on the surface of the ink droplet to determine the volume or surface shape of the droplet ( Patent Document 1).

JP, 2015-125125, A

  As described above, in the method of calculating the volume or the surface shape by using the brightness information of the droplet, the amount of light reflected from the surface of the droplet to be measured is an important factor that determines the measurement accuracy.

  However, the flatter the droplet shape to be measured, the smaller the difference in inclination between the droplet center and the droplet outer periphery, and in some cases the contrast of the light quantity reflected on the droplet surface may not be obtained sufficiently. In order to obtain the contrast, it is conceivable to reduce the numerical aperture NA of the imaging lens. However, if the NA is reduced, the luminance according to the shape can not be obtained in the range where the inclination of the droplet outer peripheral portion is strong. That is, when the droplet shape to be measured is flat, sufficient luminance contrast of surface reflection according to the inclination can not be obtained.

  Therefore, the problem to be solved by the present invention is that the brightness contrast can be obtained without changing the numerical aperture NA of the lens when sufficient brightness contrast can not be obtained only with the amount of light reflected from the droplet surface to be measured. It is an object of the present invention to provide an improved droplet measurement method, a droplet measurement apparatus, a method of manufacturing a device, and a device manufacturing apparatus.

  In order to solve the above-mentioned subject, a light is irradiated on the sample table which has a crevice on the surface and holds a translucent sample substrate, and the sample substrate by which a droplet was formed on the surface, and the sample substrate and the above An imaging unit that measures a light amount of reflected light from a droplet; and a measurement control unit that determines a volume or surface shape of the droplet based on luminance information of the light amount of the reflected light measured by the imaging unit; A droplet measuring device is used in which the thickness of the sample substrate is greater than the wavelength of the light and not more than the focal length of the droplet.

  In addition, a device manufacturing apparatus is used which includes the droplet measurement device, a production table for holding a print target, and a line head for applying droplets to the print target.

In addition, a translucent sample substrate having a droplet to be measured formed on the surface is set on a measurement table having a recess formed on the surface so that the position on the back side of the droplet coincides with the recess. The liquid droplets formed on the sample substrate set on the measurement table are irradiated with light and imaged by an imaging unit to reflect the amount of light reflected from the sample substrate and the liquid droplets, the thickness of the sample substrate is A droplet measurement method is used, in which the volume or surface shape of the droplet is determined based on the amount of reflected light measured by the imaging unit while measuring in a state larger than the wavelength of the light and smaller than the focal length of the droplet .
Before or after the droplet measurement method, the print target is set on the measurement table, and the functional material is discharged from the head having the nozzle to be evaluated to the print target, The method of manufacturing a device for manufacturing the print target is used.

According to this configuration, in addition to the reflected light from the droplet surface that becomes brighter toward the center of the droplet to be measured, the droplet transmits through the droplet and is reflected on the back surface of the sample substrate due to the phenomenon that the droplet behaves as a lens. The collected light is collected near the droplet to obtain a brightness distribution which becomes brighter toward the center of the droplet.

  That is, from the surface of the droplet, the light reflected on the surface of the droplet and the light transmitted through the droplet and reflected on the back surface of the sample substrate both have a luminance distribution that becomes brighter toward the center of the droplet. A high luminance contrast can be obtained as compared to the case of imaging only the reflected light.

  Therefore, when the droplet is imaged, it is easy to associate the luminance information with the inclination information, and the volume or surface shape can be obtained at high speed and with high accuracy by the luminance information of the droplet. Thus, the measurement time of the volume and shape of the droplet can be shortened, and the measurement accuracy can be improved.

A droplet discharge apparatus for discharging and applying ink of functional material to a print object, and a panel manufacturing apparatus comprising a droplet measurement apparatus for measuring droplets in advance so that the discharge amount of the ink approaches a target value. Diagram Overall flow diagram of the droplet measurement device of the present embodiment Enlarged cross section of sample substrate An enlarged plan view of a sample substrate on which a droplet to be measured is formed Configuration diagram of imaging unit Explanatory drawing which shows the path | route of the light at the time of imaging a droplet Figure showing simulation results showing the behavior of light assuming a droplet as an ideal lens A diagram showing simulation results showing the behavior of light passing through when the droplet shape is modeled Cross section of measurement table to set sample substrate Flow chart of droplet evaluation process A perspective view of a droplet discharge device combining a droplet measurement device and a droplet discharge device

  Hereinafter, the droplet measurement method of the present invention will be described based on the embodiment.

Embodiment 1
FIG. 1 shows a panel manufacturing apparatus provided with a droplet measurement device for implementing the droplet measurement method of the present invention. The panel manufacturing apparatus comprises a droplet discharge device 1, a droplet measurement device 2, a decompression chamber 3, and a droplet shape measurement device 4.

  The decompression chamber 3 is used to dry the applied droplets. The droplet measurement device 2 determines the volume or surface shape of the droplet 30 in a short time based on the brightness information obtained by imaging the droplet 30 discharged onto the sample substrate 19 by the droplet discharge device 1. . The result is fed back to the droplet discharge device 1 to bring it into a state in which the subsequent droplet discharge operation is targeted.

The droplet shape measuring device 4 provided separately from the droplet measuring device 2 is a device used to create a correspondence table between the droplet shape and the luminance information obtained by the droplet measuring device 2.
In this embodiment, a measuring device using light interference is used as the droplet shape measuring device 4.

  The droplet shape measuring device 4 may be mounted on the droplet discharge device 1, may be mounted on the droplet measurement device 2, or the droplet discharge device 1 or a droplet It may not be mounted on the measuring device 2 but may be installed alone outside the device.

Droplet Discharge Device 1
The droplet discharge device 1 for manufacturing devices such as a color filter for liquid crystal display and an organic EL display is a liquid from a line head 6 of a head unit 5 toward a printing object 7 with a liquid containing a functional material by an inkjet method. Discharge as a drop to produce a panel.

  The print target 7 is set on the production table 8 at the position of the head unit 5 in the vertically downward direction. The production table 8 is attached to a stage 9 having a drive system and conveyed in the X direction. The stage 9 has a pair of legs 10, the legs 10, and a support 11 mounted thereon. The pair of legs 10 and the support 11 are combined to form a portal gantry 12.

  A support base 13 having an elevating axis in the vertical direction (see the Z-axis direction in FIG. 1) is connected to the front surface of the gantry 12 and is movable in the vertical direction. The head unit 5 is disposed on the support 13.

  The head unit 5 comprises a distribution tank 14 and a line head 6. By moving up and down in the vertical direction Z, the gap between the print object 7 and the line head 6 is adjusted.

  The line head 6 includes a plurality of droplet discharge module heads 15 including a plurality of nozzles (not shown) for discharging ink and piezoelectric actuators (not shown) corresponding to the respective nozzles.

  The print control unit 16 supplies power and control signals for each head to each droplet discharge module head 15. The print control unit 16 also supplies control signals to drive axes in the X and Z directions. The print control unit 16 may include a correspondence table creation unit 17 and a volume calculation unit 18 described later.

  As described above, the line head 6 includes the droplet discharge module head 15 arranged across the entire width of the print object 7, and during the printing operation, the print control unit 16 transports the print object 7 in the X direction. It is possible to form a desired image over the entire width of the print target 7 by discharging droplets from the line head 6 at a predetermined timing according to the control signal from the above.

<Sample board 19>
The sample substrate 19 is a substrate measured by the droplet measurement device 2. The sample substrate 19 is set in the droplet discharge device 1 and a functional material is applied by the line head 6. The sample substrate 19 is translucent, and here, a material such as transparent glass is used.

  The sample substrate 19 can be implemented either by using the print target 7 to which a desired functional material is applied as it is or by cutting the print target 7. In this embodiment, the case where the print object 7 is cut is used as an example. The print target 7 is a product such as a display panel.

  The sample substrate 19 is set on the measurement table 21 of the position of the imaging unit 20 in the vertically downward direction.

Droplet Measurement Device 2
The method of transporting the sample substrate 19 in the droplet measurement device 2 is preferably automatic transport by a robot, but may be manual transport. In this embodiment, the process from the printing object 7 produced by the droplet discharge device 1 to the production of the sample substrate 19 is performed by the automatic robot, and the sample substrate 19 whose size becomes smaller is the droplet measurement device 2 Transfer to set to is done manually.

  The measurement table 21 on which the sample substrate 19 is set is mounted on a stage 22 having a drive system and transported in the X direction. A portal gantry 23 is fixed on the stage 22. Preferably, the gantry 23 has a drive system, and has a mechanism capable of moving the imaging unit 20 in the Y direction and the Z direction.

  The stage 22 may be fixed and the imaging unit 20 may be transported in the X direction instead of being transported in the X direction. According to this configuration, the operation range of the droplet measurement device 2 can be reduced.

  The droplet measurement device 2 has a frame 24 on which a stage 22 having a drive system is mounted. It is desirable that the gantry 24 mounts a vibration isolation table in order to exclude external vibrations. The vibration isolation table may use an active vibration isolation table that operates actively with respect to vibration, or may use a passive vibration isolation table that operates passively with respect to vibration.

  The droplet measurement device 2 includes a measurement control unit 25. The measurement control unit 25 supplies a control signal also to the drive axis in the X, Y, Z directions, and also supplies a control signal to the imaging unit 20 used when measuring a droplet. The measurement control unit 25 may include the correspondence table creation unit 26 and the volume calculation unit 27.

  The measurement control unit 25 is preferably connected to the print control unit 16 mounted on the droplet discharge device 1 through a network or the like, and an image captured by the imaging unit 20 or a droplet calculated using the image It is desirable to use a mechanism that can transfer data such as volume or surface shape.

  According to this configuration, based on the droplet volume derived by the measurement control unit 25 of the droplet measuring device 2, the driving voltage and the like when the ink is discharged by the droplet discharging device 1 is calculated for each droplet discharge module head It is possible to supply power and control signals for each head to 15.

  The imaging unit 20 will be described later with reference to FIG. 5 later.

Droplet measurement system
Next, a droplet measurement system for implementing the droplet measurement method of the present invention will be described based on FIG.

  This droplet measurement method includes substrate preparation step S10 performed using spin coating or die coating device as preparation in advance, discharge / application step S20 performed by droplet discharge device 1, droplet discharge device 1 and decompression chamber 3 Drying step S30 to be performed, imaging step S40 to be performed by droplet measurement device 2, shape measurement step S50 to be performed by droplet shape measurement device 4, correspondence table creation step S60 to be performed by print control unit 16 or measurement control unit 25; And a droplet evaluation step S70 performed by the print control unit 16 or the measurement control unit 25.

<Substrate preparation process S10>
First, referring to FIG. 3, a substrate preparation step S <b> 10 will be described which is performed in advance using a spin coat, a die coat apparatus or the like as preparation.

  The sample substrate 19 is composed of a support substrate 28 and a polymer film 29.

  For example, glass can be used as the support substrate 28. The polymer film 29 is obtained by, for example, dissolving a resist material used when forming a light emitting layer of an organic EL display in an organic solvent and applying it to a supporting substrate 28 by spin coating, die coating, or the like. The material to be the polymer film 29 is a photosensitive material made of polyimide or acrylic resin. And you may contain the fluorine in this. The resin material containing fluorine generally has high transparency, and it is not particularly limited as long as it has a fluorine atom in at least a part of repeating units of its polymer repeating unit. Examples of the resin containing a fluorine compound include fluorinated polyolefin resins, fluorinated polyimide resins, fluorinated polyacrylic resins, and the like. The film thickness is usually 0.1 to 3 μm, particularly preferably 0.8 to 1.2 μm. The following description will continue with the case where a photosensitive material made of polyimide or acrylic resin is used as an example of the polymer film 29.

  By using a fluorine-containing polymer material as the material of the polymer film 29, the polymer film 29 has a water repellent function.

  Here, the water repellency may be too high when the fluorine film is formed on the surface. In such a case, the desired contact angle can not be obtained after application / drying of the ink, so that the polymer film 29 of the sample substrate 19 is irradiated with UV light (ultraviolet light) to partially combine fluorine The water repellency of the sample substrate 19 can be controlled by cutting it.

<Discharge and application process S20>
Next, a liquid containing functional material is discharged from the line head 6 having a plurality of nozzles to be evaluated in the discharge / coating step S20 performed by the droplet discharge device 1 to form droplets on the sample substrate 19 The discharge and application process will be described.

  FIG. 4 shows a sample substrate 19 and a droplet application pattern formed thereon.

  On the sample substrate 19, there are a droplet 30 and a dummy droplet 31 for keeping the atmosphere at the time of drying of the volume measurement droplet sample constant.

  The dummy droplet 31 has a role of keeping the solvent atmosphere of the droplet 30 constant at the time of drying and keeping the contact angle α of the droplet 30 within a certain range.

  Although the number of dummy droplets 31 varies depending on the solvent of the ink used, for example, when the solvent of the ink is anisole, it is preferable to surround the outer periphery of the droplets 30 with dummy droplets of about 1 to 10 rounds. In the embodiment, two rounds of dummy droplets 31 are disposed around the droplets 30.

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

  In addition, according to the physical properties of the solvent of the ink to be used, for example, after leaving for a predetermined time on the production table 8 and naturally drying it in the air atmosphere, good. According to this configuration, it is possible to control the droplet 30 into a desired shape.

<Imaging Step S40>
In the imaging step S40, the imaging unit 20 captures an image of the droplet 30 created through the drying step S30.

  The entire configuration of the imaging unit 20 is shown in FIG. The imaging unit 20 includes a light source 32, a camera 33, a lens 34, a jig 35 for holding the camera 33 and the lens 34, a drive mechanism 37 for driving them in the X direction along the scanning axis 36, and focus adjustment. Drive mechanism 38 for driving the camera.

  The camera 33 and the lens 34 capture an image of the droplet 30 applied to the sample substrate 19 while moving along the scanning axis 36 direction. The image data of the droplet sample is sent to the correspondence table creation unit 26 and the volume calculation unit 27 provided in the measurement control unit 25.

  The camera 33 may be one equipped with an area sensor or one equipped with a line sensor. However, in the present embodiment, a camera equipped with a line sensor is used. Although the number of pixels and the pixel size may be selected in accordance with the object to be imaged, in the present embodiment, the number of pixels in the width direction is 4096, and the pixel size is 2 μm. The magnification of the lens 34 and the NA are selected in accordance with the shape of the droplet to be imaged. In the present embodiment, a lens having a magnification of 5 and an NA of about 0.1 was used.

  Preferably, a telecentric lens is used as the lens 34 to make the influence of focusing relatively small. In order to avoid the influence of the tilt of the optical axis, it is desirable to use a coaxial incident lens for illumination.

<About the path of light in the imaging step S40>
FIG. 6 shows the path of light when the droplet 30 ejected from the line head 6 on the sample substrate 19 is imaged. The arrows in FIG. 6 conceptually indicate the light path, but do not indicate the actual light traveling path.

  The parallel light light 39 emitted from the light source 32 is divided into the light 40 reflected on the surface of the droplet 30 and the light 41 refracted and entering the inside of the droplet. The light 42 reflected from the interface of the droplet 30 and the polymer film 29 and the light 50 reflected on the interface of the polymer film 29 and the support substrate 28 are refracted by the droplet 30 and the polymer film 29 and the support substrate 28. By reducing the difference in rate, the amount of light becomes small compared to the lights 40 and 41, and this embodiment is considered neglected.

  Since the light 40 reflected on the surface of the droplet 30 has a correlation with the inclination of the droplet 30, the shape of the droplet 30 can be calculated based on this light amount. That is, the light 40 reflected on the surface of the droplet 30 tends to be brighter because the inclination is smaller toward the center of the droplet 30 and to be darker because the inclination is larger toward the outer periphery of the droplet 30.

  However, as the shape of the droplet 30 becomes flat, the difference between the inclination angles of the droplet central portion and the droplet outer peripheral portion decreases, and the contrast of the light quantity reflected by the droplet surface may not be obtained sufficiently. In order to obtain the contrast, a method of reducing the numerical aperture NA of the imaging lens may be considered. However, when the NA is reduced, the luminance according to the shape can not be obtained in the range where the inclination of the droplet outer peripheral portion is strong. That is, when the droplet shape to be measured is flat, sufficient luminance contrast of surface reflection according to the inclination can not be obtained.

  Below, when sufficient contrast is not obtained only with the light 40 reflected on the surface of the droplet 30 as mentioned above, the structure which obtains higher luminance contrast is demonstrated using FIG. 7, FIG.

  FIG. 7 shows the simulation result in the case where the droplet 30 is assumed to be an ideal lens. The light 43 is a path of light which the light 39 emitted from the light source 32 transmits through the droplet 30 and reflects on the back surface 48 of the sample substrate 19.

  The light 43 is specularly reflected on the back surface 48 of the sample substrate 19, and the path of the light 43 after specular reflection is shown developed downward for easy viewing of the drawing. In this simulation, the droplet diameter is 50 μm, and the curvature radius is 450 μm. In this case, the focal length 46 is about 1000 μm.

  As shown in FIG. 7, when the thickness 47 of the sample substrate 19 is half of the focal length 46, the light 43 reflected by the back surface 48 of the sample substrate 19 is condensed on a point P1 of the surface 49 of the sample substrate 19. Since the focus of the lens 34 of the imaging unit 20 is in the vicinity of the surface 49 of the sample substrate 19, in addition to the luminance distribution obtained by surface reflection of the droplet 30, a luminance distribution in which the center is locally brightened is added. A high brightness contrast can be obtained as compared with the case of only the brightness distribution of the light 40 reflected on the surface of the droplet 30.

  When the thickness 47 of the sample substrate 19 is larger than half of the focal length 46, the distance between the point at which the light 43 reflected by the back surface 48 of the sample substrate 19 is collected and the distance between the surface 49 of the sample substrate 19 increases. When the thickness 47 of the sample substrate 19 has the same value as the focal distance 46, the light 43 reflected by the back surface 48 of the sample substrate 19 is Obtain a uniform image in the plane.

  Similarly, even if the thickness 47 of the sample substrate 19 becomes equal to or greater than the focal distance 46, the light 43 reflected by the back surface 48 of the sample substrate 19 is diffused, and a uniform image can be obtained in the plane.

  Similarly, even when the thickness 47 of the sample substrate 19 becomes smaller than half of the focal length 46, the point at which the light 43 reflected by the back surface 48 of the sample substrate 19 is condensed and the surface 49 of the sample substrate 19 Because the distance increases, the contrast of the light 43 reflected by the back surface 48 of the sample substrate 19 gradually decreases. When the thickness 47 of the sample substrate 19 approaches 0, the light 43 reflected by the back surface 48 of the sample substrate 19 obtains a uniform image in the plane.

  When the thickness 47 of the sample substrate 19 is shorter than the wavelength of the light 39, the light 39 is transmitted without being reflected by the back surface 48 of the sample substrate 19, so the thickness 47 of the sample substrate 19 is greater than the wavelength of the light 39. It is good to be long.

  Therefore, by making the thickness 47 of the sample substrate 19 larger than the wavelength of the light 39 and smaller than the focal length 46 of the droplet 30 and larger than the wavelength of the light 39, the light is reflected on the back surface 48 of the sample substrate 19. The light 43 has a distribution in which the luminance is higher at the center of the droplet 30 than at the periphery of the droplet.

  Therefore, the luminance distribution represented by the sum of the light 40 and the light 43 can obtain high luminance contrast as compared with the case of only the luminance distribution of the light 40 reflected on the surface of the droplet 30. In particular, the brightness contrast can be obtained around half of the focal length 46. Under the above conditions, high luminance contrast can be obtained, so that the droplet shape can be more accurately evaluated in the droplet evaluation step S70 described later.

<Actual conditions>
In practice, since the droplet 30 is not an ideal lens, the light 43 is not condensed at one point, but as shown in FIG. FIG. 8 is a model of the actual shape of the droplet 30 using a quartic function, and shows the result of simulating the path of light transmitted through the droplet 30. As in the case of FIG. 7, the light 43 is specularly reflected on the back surface 48 of the sample substrate 19, and the path of the light 43 after specular reflection is shown developed downward to make the figure easy to see. .

  The focal length 46 in this case is a distance at which the light collected in a minute range centered on the apex P2 of the droplet 30 is the largest when parallel light is incident from the convex side of the droplet 30. . The aforementioned minute range is the pixel size of the imaging unit derived from the sensor size of the camera in the imaging unit 20 and the magnification of the lens 34.

  Under this condition, the light 43 reflected by the back surface 48 of the sample substrate 19 is the center of the droplet 30 by making the thickness 47 of the sample substrate 19 larger than the wavelength of the light 39 and the focal distance 46 of the droplet 30 or less. A distribution is obtained in which the luminance is higher than in the outer peripheral portion of the droplet in the portion.

  Therefore, the luminance distribution represented by the sum of the light 40 and the light 43 can obtain high luminance contrast as compared with the luminance distribution of the light 40 reflected on the surface of the droplet 30.

  When the focal length of the droplet shape is unknown, it is desirable to derive the focal length experimentally using the imaging unit 20.

<Other than thickness of sample substrate 19>
In order to make the thickness of the sample substrate 19 variable, a light transmitting dummy substrate may be placed between the sample substrate 19 and the measurement table 21 and may be overlapped via a refractive liquid or the like. According to this configuration, the thickness of the sample substrate 19 can be arbitrarily adjusted in accordance with the shape of the droplet 30. The number of the dummy substrates may be one for simplification of the configuration, but in the case of a plurality of dummy substrates, the thicknesses are different from each other.

  The water repellency of the sample substrate 19 is controlled by irradiating the polymer film 29 on the sample substrate 19 with ultraviolet light without changing the thickness of the sample substrate 19, and the droplet shape is made variable. As well. According to this configuration, the shape of the droplet 30 can be arbitrarily adjusted according to the thickness of the sample substrate 19.

  The shape of the droplet may be made variable by controlling the conditions during natural drying and reduced-pressure drying after discharging the droplet 30 without changing the thickness of the sample substrate 19. Also according to this configuration, the shape of the droplet 30 can be arbitrarily adjusted according to the thickness of the sample substrate 19.

<Material of Sample Substrate 19>
It is desirable that the light 40 reflected by the surface of the droplet 30 and the light 43 reflected by the back surface 48 of the sample substrate 19 have the same light quantity. By doing so, in the case where both the light 40 reflected by the surface of the droplet 30 and the light 43 reflected by the back surface 48 of the sample substrate 19 have a distribution in which the luminance is higher than the droplet outer peripheral portion toward the droplet central portion. The luminance distribution represented by the sum of the light 40 and the light 43 obtains the highest luminance contrast.

  In order for the light 40 reflected by the surface of the droplet 30 and the light 43 reflected by the back surface 48 of the sample substrate 19 to have the same light quantity, the refractive index of the droplet 30 and the sample substrate 19 is the same. The refractive index of the medium in contact with the front surface and the medium in contact with the back surface 48 of the sample substrate 19 needs to be the same.

  The refractive index of the droplet 30 can not be controlled because it is determined by the ejection material. Generally, the refractive index of the resin material discharged by the ink jet method is about 1.4 to 1.6. Therefore, it is desirable that the refractive index N of the sample substrate 19 is also about 1.4 ≦ N ≦ 1.6.

  Therefore, it is desirable to use glass or the like for the sample substrate 19. In the present embodiment, transparent glass having a refractive index of 1.5 is used as the sample substrate 19. In addition, if it is the same refractive index, you may use a resin film etc., for example. By doing so, it is possible to save the holding space because the sample substrate 19 can be stored, for example, in a rolled shape.

  The light 42 reflected from the interface between the droplet 30 and the sample substrate 19 is sufficiently smaller than the light 40 reflected from the surface of the droplet 30 if the droplet 30 and the sample substrate 19 are equivalent. Can be ignored. In the present embodiment, the refractive index of the droplet 30 is 1.6, and the refractive index of the sample substrate 19 is 1.5.

As described above, the refractive index of the medium in contact with the surface of the droplet 30 and the medium in contact with the back surface of the sample substrate 19 must be the same, that is, the same medium must be used. In this embodiment, the medium is aired.
Recess 44
In the present embodiment, in order to make the medium in contact with the back surface of the sample substrate 19 uniform air, as shown in FIG. 9, the measurement table 21 is configured to have a recess 44 on the top surface. More specifically, as shown in FIG. 9, the recess 44 is a measurement table so that the back surface of the sample substrate 19 at the position of the droplet 30 formed on the sample substrate 19 does not contact the upper surface of the measurement table 21. 21 is formed.

In addition to the recess 44, a suction path 45 opened on the upper surface of the measurement table 21 is formed inside the measurement table 21, and the sample substrate 19 set on the measurement table 21 as described above is suctioned. By suction from the passage 45, it is adsorbed and held on the upper surface of the measurement table 21.

  According to this configuration, the medium in contact with the surface of the droplet 30 and the medium in contact with the back surface of the sample substrate 19 can both be air, and can have the same refractive index.

<Shape Measurement Step S50, Correspondence Table Creation Step S60, Droplet Evaluation Step S70>
Next, droplet evaluation step S70 for calculating the volume or surface shape of each droplet using image data of droplets obtained in imaging step S40 (see FIG. 2), shape measurement step S50, and correspondence table creation Step S60 will be described with reference to FIG.

Before describing the droplet evaluation step S70 shown in FIG. 10, a shape measurement step S50 and a correspondence table creation step S60 will be described, in which a correspondence table necessary for execution of the droplet evaluation step S70 is created in advance.
<Shape measurement process S50>
The shape measuring step S50 is a step of measuring, with the droplet shape measuring device 4, the shape of the droplet at a predetermined position extracted from among the plurality of droplets targeted for imaging (target for evaluation) in the imaging step S40. is there. Position coordinate data (x, y, z) on the three-dimensional coordinate system (X-Y-Z coordinate system) of the surface of the droplet is measured by the droplet shape measuring apparatus 4 described above.

<Corresponding table creation process S60>
Correspondence table preparation process S60 calculates the inclination in the position on the three-dimensional coordinate system of the surface of a droplet from position coordinate data (x, y, z) based on each profile measured at shape measurement process S50, and A correspondence table showing the correspondence between the determined inclination and the luminance ratio at a position on the two-dimensional coordinate system corresponding to the position (this luminance ratio is calculated from the luminance data of the droplet obtained in the imaging step S40) create. In the present embodiment, the correspondence table is created by the correspondence table creation unit 26 of the measurement control unit 25. The correspondence table creation unit 17 of the print control unit 16 may create the calculation time in parallel.

<Droplet evaluation process S70>
Next, the droplet evaluation step S70 of FIG. 10 will be described.

  The droplet evaluation step S70 may be performed by the volume calculation unit 27 of the measurement control unit 25, but may be performed by the volume calculation unit 18 of the print control unit 16 for parallelization of calculation time.

  First, in step S71 of the droplet evaluation step S70, the position of each droplet is specified from the images of all droplets ejected from all the nozzles to be evaluated, which are imaged in the imaging step S40, and A "droplet-by-droplet image" cut off for each droplet is created.

  In step S72 of the droplet evaluation step S70, using the "droplet-by-droplet image" obtained in step S71, the luminance ratio is determined for each droplet in order from the luminance information of the image, and the above-mentioned correspondence table is used Then, all inclinations at pixel positions of respective pixels included in a plurality of pixels corresponding to an image of one droplet are calculated.

  In step S73 of the droplet evaluation step S70, the height (temporary value) of each pixel position in the Z direction is calculated using all the tilt information of each pixel position obtained in step S72 for one droplet image. calculate.

  Next, in step S74 of the droplet evaluation step S70, the droplet outer peripheral portion is calculated using the luminance information of the image.

  Next, the height (provisional value) at the outer peripheral portion is calculated using the droplet outer peripheral portion obtained at step S74 and the height (temporary value) at each pixel position obtained at step S73. The height at the outer peripheral portion is preferably determined by averaging the heights at pixel positions within a certain distance from the droplet outer peripheral portion determined from the droplet outer peripheral portion.

  In step S75 of the droplet evaluation step S70, the height (temporary value) at each pixel position obtained in step S73 is obtained so that the height (temporary value) in the outer peripheral portion obtained as described above becomes 0. Offsets are given to the heights at all pixel positions by subtracting the heights (provisional values) at the outer peripheral portion from the above, and the heights (true values) at each pixel position are calculated.

  In step S76 of the droplet evaluation step S70, the height (true value) at each pixel position obtained in step S75 and the pixel position inside the droplet outer peripheral portion obtained in step S74 correspond to each pixel position The product of the area of the pixel is added to all of one sample droplet to obtain the volume of the one droplet.

  In step S77 of the droplet evaluation step S70, it is determined whether calculation of droplet volume V has been completed for all droplets, and if it is determined that the calculation has not been completed, the process returns to immediately before step S71. Steps S72 to S76 are repeated, and if it is determined that the process is completed, the process proceeds to step S78.

  In step S78, the variation amount between the determined droplet volume and the predetermined target droplet volume of the nozzle droplet is determined for all droplets of the nozzle to be evaluated in step S76. The print control unit 16 of the droplet discharge device 1 is instructed by the processing result of the evaluation step S70, and the voltage applied to the piezoelectric actuator corresponding to each nozzle is adjusted so as to discharge the volume of the target value.

  As described above, the volume or shape of droplets discharged by the line head 6 of the droplet discharge device 1 can be measured at high speed with high accuracy by the droplet measurement device 2, and measurement accuracy can be secured, for example, In addition, it is possible to rapidly perform measurement for managing color unevenness and the like of the print target and calibration of the ink jet apparatus.

  Therefore, for example, it is useful for utilization of the droplet discharge-type printing apparatus for coating formation of the organic luminescent material in manufacture of an organic electroluminescent display panel.

Second Embodiment
Although the droplet measurement device 2 is provided separately from the droplet discharge device 1 in the first embodiment, it may be combined as shown in FIG. FIG. 11 is a perspective view of a droplet discharge device in which the droplet measurement device 2 and the droplet discharge device 1 are united.

  The imaging unit 20 is provided in the support unit 11 of the droplet discharge device 1. A recess 44 is formed on the measurement table 21 of the droplet measurement device 2 on the production table 8. Then, the brightness information of the sample substrate 19 captured by the imaging unit 20 can be processed as shown in FIG.

  In the present embodiment, since the droplet discharge module head 15 is disposed in the longitudinal direction in the sub scanning direction of the stage 9, the recess 44 is also provided to be elongated in the sub scanning direction of the stage 9. preferable.

  In this case, it is possible to form droplets by discharging from the line head 6 in accordance with the position of the recess 44 formed on the production table 8. As in the case of the first embodiment, it is not necessary to convey the sample substrate 19 on which the droplets are formed to the droplet measurement device 2 and set it on the measurement table 21 in alignment.

  The evaluation of the line head 6 can be easily performed in a short time as well as the production of the print target 7.

Third Embodiment
In the first embodiment, when the print target 7 produced by the droplet discharge device 1 is used as the sample substrate 19 as it is, or when the print target 7 is cut into the sample substrate 19, that is, the droplets have been printed. The case of setting the sample substrate 19 of the above in the measurement table 21 of the droplet measurement device 2 and creating the correspondence table has been described.

  However, the line head 6 to be used in the droplet discharge device 1 can be set on the side of the droplet measurement device 2.

  That is, the sample substrate 19 on which the droplet 30 and the dummy droplet 31 are not formed is set on the measurement table 21 of the droplet measurement device 2. Thereafter, using the line head 6 scheduled to be used in the droplet discharge device 1 in the droplet measurement device 2, the droplets 30 and the dummy liquid on the sample substrate 19 corresponding to the position of the recess 44 of the measurement table 21 Print the drop 31. Thereafter, the formed droplet 30 is imaged by the imaging unit 20.

As a result, after that, the correspondence table is created as in the first embodiment, and transmitted to the print control unit 16 of the droplet discharge device 1, whereby the discharge amount of each head of the line head 6 is accurate. The target value can be approached.
(as a whole)
Embodiments 1 to 3 can be combined.

  The present invention contributes to the enhancement of performance of a droplet discharge type printing apparatus for manufacturing a color filter of a liquid crystal display, a device such as an organic EL display, and the like.

DESCRIPTION OF SYMBOLS 1 droplet discharge device 2 droplet measuring device 3 pressure reducing chamber 4 droplet shape measuring device 5 head unit 6 line head 7 printing object 8 production table 9 stage 10 leg portion 11 support portion 12 gantry 13 support base 14 distribution tank 15 liquid Drop ejection module head 16 printing control unit 17 correspondence table preparation unit 18 volume calculation unit 19 sample substrate 20 imaging unit 21 measurement table 22 stage 23 gantry 24 gantry 25 measurement control unit 26 correspondence table preparation unit 27 volume calculation unit 28 support substrate 29 height Molecular film 30 Droplet 31 Dummy droplet 32 Light source 33 Camera 34 Lens 35 Jig 36 Scanning axis 37 Drive mechanism 38 Z direction drive mechanism 39, 40, 41, 42, 43 Light 44 Recess 45 Suction path 46 Focal distance 47 Thickness 48 Backside 49 Frontside 50 Light S10 Substrate preparation process S20 Application Extent S30 drying step S40 imaging step S50 shape measurement step S60 corresponding table creation step S70 droplets evaluation step

Claims (11)

A measurement table having a recess on the surface and holding a translucent sample substrate;
An imaging unit configured to irradiate light onto the sample substrate having a droplet formed on the surface to measure an amount of light reflected from the sample substrate and the droplet;
Providing a measurement control unit for obtaining the volume or surface shape of the droplet based on brightness information of the light amount of the reflected light measured by the imaging unit;
The droplet measuring device, wherein a thickness of the sample substrate is larger than a wavelength of the light and equal to or less than a focal length of the droplet. 2. The droplet measurement according to claim 1, wherein the focal distance of the droplet is a distance at which the light is incident from the convex side of the droplet and the amount of light collected in a minute range centered on the vertex increases. apparatus. The droplet measurement device according to claim 2, wherein the minute range is a pixel size derived from a width of a sensor of a camera in the imaging unit and a magnification of a lens in the imaging unit. The refractive index N of the sample substrate is 1.4 ≦ N ≦ 1.6.
The droplet measurement device according to any one of claims 1 to 3. The droplet measurement device according to any one of claims 1 to 4, wherein one or a plurality of transparent dummy substrates having different thicknesses are disposed between the sample substrate and the measurement table. A water-repellent polymer film is formed on the surface of the sample substrate.
The droplet measurement device according to claim 5. The droplet measurement device according to any one of claims 1 to 6,
A production table for holding print objects,
And a line head for applying a droplet to the print target. The device manufacturing apparatus according to claim 7, wherein the production table is used as a table of the droplet measurement device. The translucent sample substrate having the droplet to be measured formed on the surface is set on the measurement table having the recess formed on the surface so that the position on the back side of the droplet coincides with the recess,
The droplets formed on the sample substrate set on the measurement table are irradiated with light and imaged by an imaging unit to reflect the amount of light reflected from the sample substrate and the droplets, and the thickness of the sample substrate is the thickness of the sample substrate Measured in a state larger than the wavelength of light and smaller than the focal length of the droplet,
A droplet measurement method, wherein the volume or surface shape of the droplet is determined based on the reflected light quantity measured by the imaging unit. Set the translucent sample substrate on the measurement table with the recess formed on the surface,
The functional material is discharged from a head having a nozzle to be evaluated toward the position of the recess of the measurement table to form a droplet on the surface of the sample substrate;
Imaging the droplet of the sample substrate by an imaging unit to measure the amount of reflected light from the sample substrate and the droplet;
The droplet formed on the sample substrate set on the measurement table is irradiated with light and imaged by an imaging unit to reflect the amount of light reflected from the sample substrate and the droplet, the thickness of the sample substrate is It is measured in a state larger than the wavelength of the light and equal to or less than the focal length of the droplet,
The droplet measuring method which evaluates the nozzle of the said head by calculating | requiring the volume or surface shape of the said droplet based on the reflected light quantity which the said imaging part measured. Before or after the droplet measurement method according to claim 10,
A manufacturing method of a device which sets a printing subject to the measurement table, discharges the functional material to the printing subject from a head having a nozzle to be evaluated, and manufactures the printing subject.

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