JP5321090B2 - Liquid volume measuring method, liquid volume measuring apparatus, and electro-optical device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology of measuring an liquid quantity of droplets dropped to a discharged area, in a short time. <P>SOLUTION: The method includes a measurement step of measuring liquid level heights &Delta;H1, &Delta;H2 of the droplets at two positions D2, D3 in three different positions D1, D2, D3 on a line along a short direction perpendicular to an elongated direction of the discharged area, defining a liquid level height of the droplets at a position D1 among the three positions as a standard height; and a determining step of computing a curvature radius R of a circular arc, which approximates a liquid level shape of the droplets along the short direction, from liquid level heights of the droplets at the other two measured positions D2, D3 and the three positions D1, D2, D3 and determines the liquid quantity of the droplets from the computed curvature radius R. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a liquid amount measuring method, a liquid amount measuring apparatus, and a method for manufacturing an electro-optical device.

  In recent years, a display device using an electroluminescence element (EL element) which is a thin self-luminous element as a display element has been widely used. The EL element emits emitted light having a desired brightness by passing a current through a light emitting layer formed of a light emitting material. The light emitting layer is formed by, for example, a so-called ink jet method in which a liquid material is discharged from a discharge head that moves relative to a substrate to a discharge target region (pixel region) partitioned by a bank (partition) on a predetermined substrate. A predetermined amount of liquid droplets are dropped by discharging a liquid material containing a light emitting material. Thereafter, the discharged liquid is solidified by a drying process such as vacuum drying or heat drying.

  As is well known, the luminance of the emitted light depends on the thickness of the formed light emitting layer. For this reason, the variation in the thickness of the light emitting layer to be formed becomes the variation in luminance as it is. Accordingly, it is important that the amount of the liquid discharged and dropped onto the discharge region is a predetermined amount so that the thickness of the light emitting layer formed in each discharge region is constant. It is.

  However, when a liquid material is ejected and dropped onto an ejection area formed on the substrate surface using an ink jet method, it is caused by performance variation or shape variation of functional components (for example, piezoelectric elements) constituting the ejection head. Thus, there are many variations in the discharge amount of the liquid material for each nozzle provided in the discharge head. For this reason, it is necessary to accurately measure the amount of liquid discharged from the nozzle and dropped onto the discharge region. For example, Patent Document 1 discloses a technique for accurately measuring the volume of a minute droplet. ing.

JP-A-2005-121401

  In the technique disclosed in Patent Document 1, the contour (height) of the liquid surface is measured at a plurality of locations while scanning the line segment connecting the center of the droplet dropped on the horizontal plane and the outer periphery of the droplet in the radial direction of the droplet. It is a technology to measure. Therefore, in order to accurately measure the liquid amount, it is necessary to increase the number of measurement points. In particular, the area to be ejected that is actually formed on the substrate surface is often formed in a shape having one of the longitudinal directions, such as an oval shape, and in such a case, it is necessary to perform measurement in line segments in many directions. Therefore, the number of measurement points is further increased.

  However, when the number of measurement points is increased in this way, the measurement time becomes longer, and as a result, the time required to correct the discharge amount of the liquid material from the nozzle becomes longer. As a result, the liquid already dripped onto the discharge area may start drying (natural drying), and the drying conditions in subsequent drying processes such as vacuum drying and heat drying will not be uniform, and may be extended. In this case, there arises a problem that the thickness of the light emitting layer solidified in the discharged region is not uniform. For this reason, there has been a demand for a technique for measuring the amount of liquid droplets dropped on a discharge area in a short time.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] A liquid amount measuring method for measuring a liquid amount of a droplet dropped on a discharge target region of a droplet formed on a substrate surface so that one direction has a long longitudinal direction. Then, at three different positions on the line segment along the short direction perpendicular to the longitudinal direction of the target area, the liquid level of the droplet at one of the three positions is used as a reference. From the measurement step of measuring the liquid level of the liquid droplets at the two positions, and the liquid level height of the liquid droplets and the three positions at the two other positions measured in the lateral direction. And a measuring step of calculating a radius of curvature of an arc that approximates the liquid surface shape of the droplet along, and measuring the liquid volume of the droplet from the calculated radius of curvature.

  When the discharge region has a longitudinal direction, in the short direction perpendicular to the longitudinal direction, the liquid surface may have an approximately arc shape, and the radius of curvature of the arc may be considered to represent the liquid amount of the droplet. In such a case, by calculating and calculating the radius of curvature of the arc presented by the liquid surface of the liquid droplet, the liquid amount of the liquid droplet dropped onto the discharge target region can be measured. At this time, according to this measuring method, the liquid level can be measured in a short time since the three measuring points for measuring the height of the liquid level are sufficient in the short direction. As a result, it is possible to quickly correct the amount of liquid droplets dropped in the discharged region. Further, even if the height of the entire liquid level of the liquid droplets dropped on the discharge target region due to the undulation of the substrate or the like, the liquid level height at the three positions is relative to one position as a reference. Since the height is measured, it is possible to avoid the influence of the swell of the substrate on the measured value of the liquid amount.

  [Application Example 2] In the liquid amount measuring method, the measuring step includes setting a position of a line segment along the short direction as a substantially central position in the longitudinal direction.

  According to this method, the liquid level can be measured in a state where there is little variation in the liquid level shape in the short direction. As a result, it is possible to accurately measure the liquid amount of the liquid droplets dropped on the discharged region.

  Application Example 3 In the liquid amount measurement method, the measurement step is characterized in that the one position is set to a substantially central position in a short direction of the discharge area.

  According to this method, the radius of curvature can be calculated with high accuracy. As a result, it is possible to accurately measure the liquid amount of the liquid droplets dropped on the discharged region.

  Application Example 4 In the liquid amount measuring method, the measuring step may be performed by changing the other two positions from a center position in the short direction to a width in the short direction of the discharge area. It is characterized by having a remote position.

  According to this method, the radius of curvature can be calculated with high accuracy. As a result, it is possible to accurately measure the liquid amount of the liquid droplets dropped on the discharged region.

  Application Example 5 In the liquid amount measuring method, the measuring step uses a table in which a correspondence relationship between the liquid amount of the droplet and the radius of curvature is determined in advance according to the shape of the discharge target region. The liquid amount of the droplet is measured from the calculated curvature radius.

  According to this method, since the load associated with the arithmetic processing is reduced, the liquid amount of the liquid droplets dropped on the discharge target region can be measured in a short time.

  Application Example 6 In the liquid amount measurement method, the discharge target region is obtained by using the acquisition step of acquiring information on the shape and the position on the substrate surface, and the information on the shape and the position. And a calculation step of calculating the three positions with respect to the region.

  According to this method, even when the shape and arrangement of the discharge area formed on the substrate surface are different, information on the shape and position of the discharge area is obtained, and the shape center position and the short direction of the discharge area are obtained. And can be calculated.

  [Application Example 7] In the liquid amount measuring method, the acquisition step includes information on the shape and the position of the discharged region by optically reading the discharged region formed on the substrate surface. It is characterized by acquiring.

  According to this method, even when the shape and arrangement of the discharged region formed on the substrate surface are different, the shape of the discharged region formed on the substrate surface and the position on the substrate surface are optically read and acquired. can do.

  Application Example 8 A liquid amount measuring apparatus for measuring the amount of liquid droplets dropped on a region to be discharged of a droplet formed on a substrate surface so that one direction has a long longitudinal direction. In one of the three positions, the measuring means for measuring the liquid level of the droplet and three different positions on the line segment perpendicular to the longitudinal direction of the discharge target region. Using the liquid level height of the liquid droplets at two positions as a reference, the liquid level height of the liquid droplets at the other two positions is measured using the measuring means, and the other two measured From the liquid level height of the droplet at three positions and the three positions, a radius of curvature of an arc approximating the liquid level shape of the droplet along the short direction is calculated, and the calculated radius of curvature is used to calculate the radius of curvature. And a measuring unit for measuring the liquid amount of the liquid droplets.

  When the liquid surface has an approximately arc shape, the radius of curvature of the arc may be considered to represent the liquid volume of the droplet, so the droplet volume is measured by calculating the radius of curvature of the arc presented by the droplet. be able to. Therefore, according to this method, since three measurement points are required in the short direction, measurement can be performed in a short time. As a result, it is possible to quickly correct the amount of liquid droplets to be dropped. Further, even if the height of the entire liquid level of the liquid droplets dropped on the discharge target region due to the undulation of the substrate or the like, the liquid level height at the three positions is relative to one position as a reference. Since the height is measured, it is possible to avoid the influence of the swell of the substrate on the measured value of the liquid amount.

  Application Example 9 In the liquid amount measuring apparatus, information relating to a moving unit that moves the measuring unit relative to the substrate surface in an in-plane direction, a shape of the discharge target region, and a position on the substrate surface. An acquisition unit to acquire, and a calculation unit to calculate the three positions using the acquired information about the shape and the position, and the measurement unit is calculated using the moving unit The measurement is performed by moving to three positions.

  According to this configuration, the position of the liquid surface can be measured by relatively moving the measuring means to the three positions in the short direction.

  Application Example 10 In the liquid amount measurement apparatus, the liquid amount measurement apparatus includes a reading unit that optically reads the discharge target region formed on the substrate surface, and the acquisition unit uses the reading unit to discharge the discharge target region. By reading, information on the shape and the position of the ejection region is obtained.

  According to this configuration, even if the discharge target area formed on the substrate surface is different for each substrate, information on the shape and position of the discharge target area is acquired, so three positions in the short direction can be acquired. it can.

  Application Example 11 In the liquid amount measurement apparatus, the measurement unit sets the one position as a substantially center position in a short direction of the discharge area.

  According to this configuration, the radius of curvature can be calculated with high accuracy. As a result, it is possible to accurately measure the liquid amount of the liquid droplets dropped on the discharged region.

  [Application Example 12] In the liquid amount measuring apparatus, the measurement unit sets the other two positions to ¼ or more of the width in the short direction of the discharge area from the center position in the short direction. It is characterized by having a remote position.

  According to this configuration, the radius of curvature can be calculated with high accuracy. As a result, it is possible to accurately measure the liquid amount of the liquid droplets dropped on the discharged region.

  Application Example 13 In the liquid amount measurement apparatus, the measurement unit uses a table in which a correspondence relationship between the liquid amount of the droplet and the radius of curvature is determined in advance according to the shape of the discharge target region. The liquid amount of the droplet is measured from the calculated curvature radius.

  According to this configuration, since the load associated with the arithmetic processing is reduced, it is possible to measure the amount of liquid droplets dropped on the discharge target region in a short time.

  [Application Example 14] Electro-optical in which a display element is formed by dropping a predetermined amount of droplets onto a region to be discharged of a droplet formed on a substrate surface so that one direction has a long longitudinal direction. A method for manufacturing an apparatus, comprising: a dropping step of dropping the droplets onto the discharge target region by discharging the droplets onto the discharge target region using a discharge device; and the dropped liquid Based on the measurement step of measuring the liquid volume of the droplet using the liquid volume measuring method and the measured liquid volume of the droplet, the droplet volume discharged by the discharge device is set to the predetermined amount. And a correction step of correcting the discharge amount of the discharge device.

  According to this method, it is possible to measure the amount of liquid dropped on the discharge target area in a short time. In addition, even if the height of the entire liquid level of the liquid droplets dropped on the discharge target region due to the waviness of the substrate or the like, the liquid level height at the two positions is set to the liquid level height at the center position of the shape. Since it is measured as a relative height as a reference, it is possible to avoid the influence of the undulation of the substrate on the measured value of the liquid amount. As a result, it is possible to correct the liquid amount of the dropped liquid droplets quickly and accurately.

  [Application Example 15] Electro-optical in which a display element is formed by dropping a predetermined amount of a droplet onto a discharge target region of a droplet formed on a substrate surface so that one direction has a long longitudinal direction. A method for manufacturing an apparatus, comprising: a dropping step of dropping the droplets onto the discharge target region by discharging the droplets onto the discharge target region using a discharge device; and the dropped liquid Based on the measurement step of measuring the liquid volume of the droplet using the liquid volume measuring device and the measured liquid volume of the liquid droplet, the liquid droplet volume discharged by the discharge device is set to the predetermined amount. And a correction step of correcting the discharge amount of the discharge device.

  According to this method, it is possible to measure the amount of liquid dropped on the discharge target area in a short time. In addition, even if the height of the entire liquid level of the liquid droplets dropped on the discharge target region due to the waviness of the substrate or the like, the liquid level height at the two positions is set to the liquid level height at the center position of the shape. Since it is measured as a relative height as a reference, it is possible to avoid the influence of the undulation of the substrate on the measured value of the liquid amount. As a result, it is possible to correct the liquid amount of the dropped liquid droplets quickly and accurately.

  Hereinafter, the present invention will be described based on embodiments. In the drawings used in the following description, it is needless to say that each dimension may be exaggerated as necessary for convenience of description, and does not necessarily match the actual dimension.

(First embodiment: Liquid volume measuring device)
FIG. 1 is a schematic diagram showing a schematic configuration of a liquid amount measuring apparatus 100 as an embodiment of the present invention. As shown in the figure, the liquid amount measuring apparatus 100 includes an XY table 105 as a moving unit including a table 105a that moves in the X-axis direction and a table 105b that moves in the Y-axis direction orthogonal to the X-axis direction, and a reading device. A camera 20 as means, a measuring instrument 30 as measuring means, and a control device 10 for controlling the liquid amount measuring apparatus 100 are provided.

  The table 105a includes a pair of guide rails 101 provided linearly, an air slider and a linear motor (not shown) provided inside the guide rail 101, and one linear axial direction by the control device 10. That is, it moves in the X-axis direction. The table 105 b includes a pair of guide rails 102 provided linearly, an air slider and a linear motor (not shown) provided inside the guide rail 102, and one linear axial direction by the control device 10. That is, it moves in the Y-axis direction. The table 105a is provided with a suction means (for example, air suction) (not shown) for placing the substrate P, and is configured to be able to suck and fix the substrate P on the table 105a. Note that the XY table 105 may be moved in the X-axis direction and the Y-axis direction by other configurations such as a combination of a motor and a ball screw.

  The camera 20 and the measuring instrument 30 are fixed by a support member (not shown) at a predetermined distance from the substrate P in a substantially normal direction with respect to the substrate P attracted to the XY table 105. The camera 20 incorporates an imaging element (for example, a CCD element) and optically reads a discharge target area of a droplet formed on the substrate P. The measuring device 30 measures the liquid level height of the liquid droplets dropped on the discharge area.

  In this embodiment, the camera 20 or the measuring instrument 30 is fixed and the XY table 105 is moved. Conversely, the XY table 105 is fixed and the camera 20 or the measuring instrument 30 is moved. It does not matter.

  By the way, the measuring instrument 30 in the present embodiment uses a three-dimensional non-contact surface measuring instrument (for example, Nippon Binary Co., Ltd., trade name “Nano Station 200”) in order to accurately measure the liquid level. This measuring instrument 30 is a system that obtains height information from its wavelength distribution by applying the axial chromatic aberration of white light. Further, the measuring instrument 30 can be measured even if the light intensity of white light is weakened, and has an advantage that the influence on the performance of the liquid droplet can be suppressed during the liquid level measurement. Of course, a laser-type measuring device (so-called laser-type distance measuring device) that obtains liquid surface height information from the time it takes to emit the reflected laser light to return may be used.

  The control device 10 controls the movement of the XY table 105 described above, and acquires data on the shape and position of the discharged region formed on the substrate P from the image of the discharged region captured by the camera 20. Further, the liquid level height data of the liquid droplets dropped on the discharge area measured by the measuring instrument 30 is acquired.

  Next, the control device 10 will be described in detail with reference to FIG. FIG. 2 is a block diagram illustrating a schematic configuration of the control device 10. The control device 10 has a computer function and includes a CPU 11, a RAM 12, a ROM 13, an interface unit 18, and a table memory 15 that are connected to each other via a bus line.

  The CPU 11 functions as the acquisition unit 111, the calculation unit 112, the measurement unit 113, and the measurement unit 114 by operating according to the measurement program stored in the ROM 13 while using the RAM 12 as a working memory. The interface unit 18 functions as an interface for exchanging data between the control device 10, the XY table 105, the measuring instrument 30, and the camera 20.

  In the liquid amount measuring apparatus 100 according to the present embodiment, the acquisition unit 111 acquires the shape and position data of the ejection target area captured by the camera 20 via the interface unit 18. The calculation unit 112 calculates the center position in the longitudinal direction of the ejection region and the short direction perpendicular to the longitudinal direction from the acquired shape and position data of the ejection region. The measurement unit 113 moves the XY table 105 via the interface unit 18 so that the measurement position of the measurement device 30 comes to three positions in the calculated short direction, and the measurement device 30 performs measurement at these three positions. Data on the liquid level to be obtained is acquired via the interface unit 18, and the relative heights of the two remaining positions are measured with one position as a reference. The measuring unit 114 calculates the radius of curvature of the arc that approximates the liquid surface shape of the droplet from the relative height of the two positions and the three positions, and uses the table memory 15 from the calculated radius of curvature. Then, the liquid amount of the liquid droplets dropped on the discharged area is measured.

  Next, in the present embodiment, the pixel region is determined by the radius of curvature calculated using the liquid surface heights at the three positions in the short direction with respect to the liquid droplets dropped on the discharge target region formed on the substrate P. The reason why the amount of liquid droplets dropped on the liquid crystal can be measured will be described below with reference to FIGS.

  FIG. 3 is an explanatory diagram showing a state in which the functional liquid is discharged to the substrate P and a discharge target region formed as a pixel region on the substrate P. Therefore, hereinafter, the discharge target region is referred to as a pixel region. As shown in the drawing, in this embodiment, for the sake of simplicity, the substrate P has a total of 24 pixels (G1) having 4 pixels in the Y-axis direction (vertical direction in the drawing) and 6 pixels in the X-axis direction (horizontal direction in the drawing). To G24) are formed. Needless to say, in practice, many pixels such as several hundred pixels are formed in the X-axis and Y-axis directions.

  In the present embodiment, the pixel shape is an ellipse having a longitudinal direction in the Y-axis direction. Of course, as long as the shape has a longitudinal direction in one direction, the shape is not limited to this, and may be a rectangular shape or a rounded rectangular shape, an elliptical shape, or a rhombus shape.

  In this embodiment, an organic EL element is formed in a pixel region formed on the substrate P. Accordingly, a functional liquid containing a predetermined solute and a solvent is ejected from the nozzle row 200n provided in the ejection head 200 to each pixel area as shown in the figure, whereby a predetermined amount of the functional liquid is dropped on each pixel area. The For example, in the present embodiment, the ejection head moves relative to the substrate P in the X-axis direction, so that each pixel region formed on the substrate P from the nozzle row 200n provided in the ejection head 200 is changed. That is, the functional liquid is discharged.

  FIG. 4 is a schematic diagram showing the configuration of the ejection head 200. As shown in the figure, the nozzle row 200n has minute openings, and is usually formed by piercing the ejection head 200 with several tens to several hundreds of nozzles at a predetermined pitch. The nozzle row 200n that is formed has a discharge mechanism for each nozzle, and generates pressure on the liquid material in the discharge head 200 to discharge a predetermined amount of functional liquid from each nozzle. ing. Of course, the discharge mechanism has the same structure for all nozzles.

  In the present embodiment, the discharge mechanism has the structure shown in the blow-out portion in FIG. 4 and uses the piezoelectric element 2 as a driving body (actuator). That is, when a voltage waveform is applied between the electrodes COM and GND at both ends of the piezoelectric element 2, the piezoelectric element 2 contracts or expands due to electrostrictive properties, and the diaphragm 3 is bent in the direction of the arrow, and in the middle of the flow path. The functional liquid present in the formed pressurizing chamber 4 is pressurized. As a result, the pressurized functional liquid is discharged as droplets 9 from the nozzles formed in the nozzle plate 8. The discharge mechanism may be, for example, a so-called thermal method using a heating element as a driver.

  The nozzle row 200n drilled in the ejection head 200 may have a plurality of nozzle rows such as two rows. For example, in the case of two rows, the nozzle drilling positions are half-pitch between the nozzle rows. There may be a relationship that forms a staggered staggered arrangement. Further, a plurality of ejection heads 200 may be provided. In this way, the required number of ejection heads 200 and nozzle rows 200n are provided according to the number and range of pixel regions formed or the size of the substrate P.

  As can be understood from the above description, in the nozzle row 200n, the amount of liquid droplets ejected from each nozzle due to variations in the opening diameter of each nozzle formed, variations in electrostrictive properties of the piezoelectric element 2, and the like. This is different.

  In this way, the functional liquid is ejected from the ejection head 200 to each pixel region to form the organic EL elements. Here, it is assumed that the organic EL element has a top emission structure in which light is emitted from the display element forming surface side with respect to the substrate P. Of course, the organic EL element may have a bottom emission structure in which light is emitted from the side opposite to the display element forming surface side with respect to the substrate P instead of the top emission structure.

  Next, a specific configuration of the organic EL element to be formed will be described with reference to FIG. FIG. 5 is a schematic diagram illustrating a configuration of a functional layer included in the organic EL element. FIG. 5A is a plan view showing a display portion in which three pixels are arranged in the X-axis direction (horizontal direction in the drawing) in each pixel region shown in FIG. 3, and FIG. It is the schematic cross section which showed the EE cross section in Fig.5 (a), and has shown the state which formation of the organic EL element was complete | finished. FIG. 5C is a schematic cross-sectional view showing the EE cross section in FIG. 5A, and is a schematic view showing a state in which the functional layer of the organic EL element is applied and formed by discharging a functional liquid. FIG.

  As shown in FIG. 5A, each pixel region has a pixel region partitioned by a bank (hatched portion in the figure) made of an insulating organic material (for example, acrylic resin or polyimide resin) formed by etching or the like. Each has an oval shape. In each pixel region, an organic EL element capable of emitting light is formed.

  As shown in FIG. 5B, the organic EL element capable of emitting light includes a hole injection layer and a light emitting layer formed between an anode and a cathode. By the way, in this embodiment, the hole injection layer is formed by discharging a functional liquid using polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) as a solute and ethylene glycol as a solvent to the pixel region as a liquid, and then vacuuming. A PEDOT / PSS film having a predetermined thickness is formed by performing a drying process such as drying to remove the solvent. The light-emitting layer discharges a functional liquid using a fluorescent material (for example, poly (9,9-dioctylfluorene)) as a solute and 1,3,5-trimethylbenzene as a solvent to each pixel region as a liquid. Thereafter, a drying process is performed by vacuum drying or the like to form fluorescent material films each having a predetermined thickness.

  Incidentally, an inorganic insulating film is formed between the bank and the anode so that a predetermined width is exposed in the pixel region along the outer periphery of the oval pixel region. This enhances the lyophilicity with the functional liquid for forming the hole injection layer and the light emitting layer, and prevents the short circuit between the anode and the cathode by forming the hole injection layer and the light emitting layer up to the vicinity of the bank. It is to make it. Of course, when the hole injection layer and each light emitting layer can be formed up to the vicinity of the bank, it is not necessary to form the inorganic insulating film.

  Moreover, since the organic EL element of this embodiment is a top emission system, a reflective layer is formed on the surface side facing the substrate P of the anode so that the emitted light is emitted from the cathode side. Of course, when the anode also serves as the reflective layer, it is not necessary to form the reflective layer. Although not shown here, a drive element for driving the organic EL element to emit light is formed between the substrate P and the organic EL element.

  In the present embodiment, the hole injection layer and the light emitting layer are formed by discharging and applying a predetermined amount of functional liquid to each pixel region. Specifically, as shown in FIG. 5C, the function liquid of the hole injection layer and the function of the light emitting layer that form the organic EL element in each pixel region from the nozzle provided in the ejection head 200. The liquids are dropped by being discharged in a predetermined order. Then, each time the solution is dropped, a drying process is performed as described above to form a hole injection layer and a light emitting layer in each pixel region.

  Now, with respect to the organic EL element thus formed, the light emission luminance in each pixel region depends on the thickness of the light emitting layer to be formed or the magnitude of the current flowing through the light emitting layer. Therefore, it is important that the thickness of the light emitting layer sandwiched between the anode and the cathode is uniform between the pixel regions for all the pixel regions formed on the substrate P. This is because the electrical resistance exhibited by the light emitting layer is uniform over each pixel region by making it uniform, and as a result, the current flowing through the light emitting layer is also uniform between the pixel regions.

  The same applies to the hole injection layer other than the light emitting layer in order to prevent a difference in current flowing in the light emitting layer. By making the thickness of the hole injection layer uniform between the pixel regions for all the pixel regions formed on the substrate P, the current flowing in the light emitting layer is changed between the pixel regions. This is because it can be made constant. Therefore, if there is a difference in the film thickness of the light emitting layer and the hole injection layer sandwiched between the anode and the cathode between the pixel regions, for example, luminance unevenness is caused as it is.

  According to the measuring method by the liquid amount measuring apparatus 100 of the present embodiment, the liquid amount of the functional liquid dropped onto the pixel region is accurately and quickly measured to be dropped as the hole injection layer and the light emitting layer. Thus, it is possible to immediately correct the amount of the functional liquid to be a predetermined liquid amount.

(Liquid volume measuring method)
Next, the outline of the liquid amount measuring method will be described with reference to FIG. In the present embodiment, description will be made assuming that a light emitting layer is formed as a functional layer. Of course, the following description is also applicable to the hole injection layer. FIG. 6 is a schematic diagram showing a state in which a predetermined amount of a functional liquid in which the material for forming the light emitting layer is a solute and melted in a solvent is dropped in one of the pixel regions shown in FIG. The lower side of the drawing is a central sectional view in the X-axis direction, and the right side of the drawing is a central sectional view in the Y-axis direction.

  As shown in FIG. 6, when a functional liquid having a predetermined liquid amount is dropped onto the pixel area surrounded by the bank, the liquid A has a width A that is the short direction (X-axis direction) of the pixel area. It was found that the shape of the surface was almost circular. It has also been found that the liquid surface exhibits a more noticeable circular shape by applying a liquid repellent treatment to at least the planar portion of the bank. At this time, it was confirmed that the radius of curvature of the outer shape of the liquid surface formed in the width A in the short direction changes according to the amount of the functional liquid dropped onto the pixel region. Therefore, if the circular radius of curvature R exhibited by the liquid surface in the short direction is measured, it is possible to measure the amount of the functional liquid dropped onto the pixel region.

  On the other hand, in the width B, which is the longitudinal direction (Y-axis direction) of the pixel region, it has been found that the shape of the liquid surface has an approximately elliptical shape or a bowl shape with a large curvature at the central portion and a smaller curvature at the end portion. . Therefore, since the change in height ΔH of the liquid level according to the distance ΔY from the center position in the longitudinal direction is small, the circular curvature radius exhibited by the short direction is the width B in the longitudinal direction (Y-axis direction). It can be seen that there is no significant change near the center position. In other words, if the pixel region is approximately the center position in the longitudinal direction, the circular radius of curvature R in the short direction can be measured almost accurately.

  A measuring method of the liquid amount measuring apparatus 100 performed using such a shape of the liquid level will be described with reference to FIG. 2 using the flowchart of the liquid amount measuring process S30 shown in FIG.

  When this process is started, first, in step S31, the camera is manipulated on the substrate in the X-axis direction and the Y-axis direction. Specifically, in the control device 10, the CPU 11 controls the movement of the XY table 105 via the interface unit 18 and moves the camera 20 relative to the substrate P.

  Next, in step S32, the shape and position of the pixel region are acquired. The CPU 11 generates shape data of the image region from the image of the image region captured by the camera 20, for example, by image processing such as contour extraction processing. The generated shape data is attached to the RAM 12 with position data with respect to reference coordinates (not shown). Get by memorizing.

  Next, in step S33, the longitudinal center position of the pixel region is calculated. The CPU 11 calculates the longitudinal position B of the pixel region using the stored shape data, and then calculates and calculates the center position.

  Subsequently, in step S34, the width of the pixel region in the short direction is calculated. Here, the CPU 11 calculates the width in the short direction at the position along the line segment in the short direction including the center position in the long direction calculated in step S33 using the stored shape data. Note that the width in the short direction may be the constant width portion when it is formed so as to have a constant width portion along the longitudinal direction as shown in FIG. There is no need to calculate the width in the short direction.

  Next, in step S35, three positions in the short direction are set. Here, the CPU 11 calculates the center position in the short direction from the calculated width in the short direction as one position, and is the position on the line segment in the width in the short direction, and is the center in the short direction. Two positions separated from the position by a quarter or more of the width in the short direction on both sides are set as the remaining two positions.

  Subsequently, in step S36, the measuring instrument is moved to the set three positions. The CPU 11 drives the XY table 105 via the interface unit 18 and relatively moves to the three positions where the measuring instrument 30 is set.

  In step S37, the liquid level height at two positions with respect to one position is measured. Specifically, the CPU 11 first acquires the liquid level height data at one position, that is, the center position in the short direction, via the interface unit 18. Next, liquid level height data at two positions is acquired via the interface unit 18. Then, difference data between the liquid level height data at the center position in the short direction and the liquid level height data at the two positions is calculated.

  Here, the processes in steps S35 to S37 will be supplementarily described with reference to FIG. FIG. 8 is a schematic view showing a state in which the height of the functional liquid dropped onto one pixel region is measured. As shown in the figure, the height of the liquid level is measured at three positions D1, D2, and D3 indicated by black circles. The position D1 is the center position of the width A in the short side direction (X-axis direction). The position D2 is a position ΔX1 away from the position D1 by a distance ΔX1 that is 1/4 or more of the width A in the short direction, and the position D3 is 1 on the opposite side of the position D2 from the position D1 in the width A in the short direction. This is a position that is a distance ΔX2 or more than / 4.

  Thus, by setting the position D1, the position D2, and the position D3, the height of the liquid level can be accurately measured. For example, as shown in the drawing, the liquid level measured by the measuring instrument 30 at the position D2 has a significant amount of change in chromatic aberration in the optical axis direction (vertical direction in the drawing) of the measuring instrument 30, so the liquid level can be accurately measured. The height of the surface can be measured. The same applies to the position D3.

  Note that the height of the liquid level at the position D1 does not change greatly even if the detection position is deviated in the X-axis direction. Therefore, by using the height of the liquid level at the position D1 as a reference, the difference height ΔH1 of the liquid level from the position D1 at the position D2 and the difference height ΔH2 of the liquid level from the position D1 at the position D3 are This is a highly accurate value.

  Next, returning to FIG. 7, in step S38, a curvature radius calculation process is performed. The CPU 11 calculates the radius of curvature R using the three positions and the difference data of the liquid level at the two positions. Although detailed description is not given here, the position D1, the position D2, and the position D3 are the coordinates (−ΔX1, −, respectively) of the position D2 and the position D3, where the position D1 is the origin (0, 0) in FIG. Since these are represented by (ΔH1) and (ΔX2, −ΔH2), these coordinate values can be easily calculated by applying them to a known circle formula. If the difference data (ΔH1, ΔH2) of the liquid level is used in this way, measurement is performed by the undulation that occurs on the substrate P, the vertical movement of the substrate P that occurs when the XY table moves, and the like. Even if the relative distance between the vessel 30 and the liquid level changes, the radius of curvature can be calculated correctly.

  In step S39, the liquid amount is measured using a table. The CPU 11 uses the table stored in the table memory 15 to measure the amount of the functional liquid dropped on the pixel area. An example of the stored table TB is shown in FIG. The table TB defines the liquid amount C corresponding to the width A in the lateral direction and the width B in the longitudinal direction and the curvature radius R representing the shape of the pixel region. For example, if the width A in the short direction of the pixel region is the dimension A1, the width B in the longitudinal direction is the dimension B2, and the radius of curvature R is the dimension R3, the liquid amount C indicates the value C23. Therefore, the CPU 11 performs measurement by reading the value C of the liquid amount using the table TB from the calculated width A in the short direction, width B in the long direction, and the calculated radius of curvature R.

  When the calculated width A in the short direction, width B in the longitudinal direction, and calculated radius of curvature R are different from the values prepared in the table TB, the closest values may be used, or values close to each other. It is good also as using it by performing interpolation calculation using. Of course, the liquid amount C may be defined by an arithmetic expression using the width A in the lateral direction, the width B in the longitudinal direction, and the curvature radius R as variables. Although the calculation processing load increases, the liquid amount can be calculated accurately.

  As described above, the liquid amount measurement process S30 of the functional liquid dropped on one pixel area has been described. However, all the pixel areas formed on the substrate P are targeted for this liquid amount measurement process S30. By the way, in this embodiment, the ejection head 200 is scanned in the X-axis direction to eject the functional liquid from the nozzle row 200n. Therefore, between the pixel regions arranged in the X-axis direction (for example, the pixels G1, G5, G9, G13, G17, and G21), the functional liquid is discharged from the same nozzle. Can be considered to be almost the same. Therefore, in the present embodiment, the liquid amount measurement process is performed for a row of pixel regions arranged in the Y-axis direction. In this way, the liquid amount can be measured faster than the liquid amount of the functional liquid for all the pixel regions. An example thereof will be described with reference to FIG.

  FIG. 10 is an explanatory diagram showing the trajectory of the measuring instrument 30 that is moved relative to the substrate P. As shown in the figure, in the present embodiment, among the pixel regions formed on the substrate P, the amount of functional liquid dropped on these pixel regions for the pixel regions G1, G2, G3, and G4 arranged in the Y-axis direction. The measuring instrument 30 is moved relative to each other.

  For example, as shown in FIG. 10A, it moves in a sawtooth shape. In this way, the moving distance of the measuring instrument 30 can be shortened, and the measuring instrument 30 is always scanned in the pixel area from the same direction in the X-axis direction, so that, for example, misalignment due to the mechanical play of the XY table 105 is avoided. be able to. Alternatively, as shown in FIG. 10B, it may be moved in a U-shape. By doing so, the moving distance of the measuring instrument 30 can be made the shortest, so that the measurement of the amount of the functional liquid in the pixel region can be made the fastest.

  As described above, according to the liquid amount measuring apparatus 100 of the present embodiment, when the liquid surface has an approximately arc shape, it may be considered that the radius of curvature of the arc represents the liquid amount of the liquid droplet. The amount of liquid can be measured by calculating and calculating the radius of curvature of the arc presented by the liquid surface. Accordingly, since the measurement points need only be three positions in the short direction, the liquid amount can be measured in a short time. As a result, it is possible to quickly correct the amount of liquid droplets to be dropped. Further, even if the height of the entire liquid level of the liquid droplets dropped on the discharge target region due to the undulation of the substrate or the like, the liquid level height at the three positions is relative to one position as a reference. Since the height is measured, it is possible to avoid the influence of the swell of the substrate on the measured value of the liquid amount.

Second Embodiment: Method for Manufacturing Electro-Optical Device
In the above-described embodiment, the present invention is described as the liquid amount measuring device 100, and the organic EL element constituting the organic EL panel that is one of the electro-optical devices is described as being formed in the pixel region formed on the substrate P. As another embodiment, the present invention can be regarded as a method for manufacturing an organic EL panel which is one of electro-optical devices. The manufacturing method according to the present embodiment will be described with reference to the flowchart of FIG.

  First, in step S10, the functional liquid is discharged to the pixel region of the substrate. In this step, a pixel region in which a functional liquid, which is a solvent solution containing a solute that forms a functional layer (a hole injection layer or a light emitting layer), is formed on a substrate P in a pixel region in which an organic EL element is formed. On the other hand, a predetermined amount is discharged from the discharge head (see FIG. 4) and dropped.

  Next, in step S20, the substrate is moved to the liquid quantity measuring device. In this step, the substrate P on which the functional liquid has been dropped on the pixel region is moved to the liquid amount measuring apparatus 100 by a transfer device or manually.

  Next, in step S30, a liquid amount measurement process is performed. In this step, the liquid amount measuring process S30 described above is performed by the liquid amount measuring apparatus 100 in the above embodiment. Accordingly, the amount of the functional liquid dropped on each image area is accurately measured in a short time.

  Therefore, in the next step S40, the substrate is moved to the ejection device, and in the subsequent step S50, the correction amount of the functional liquid is ejected to the pixel region. In these processes, the substrate P on which the amount of the functional liquid dropped onto the pixel region is measured is moved again to the discharge device by a transfer device or manually, and the correction is determined according to the measured amount of the functional liquid. An amount of functional liquid is discharged to each pixel region.

  As described above, according to the present embodiment, since the liquid amount of the dropped functional liquid is measured in a short time after the functional liquid is dropped on the pixel area, the functional liquid dropped on the pixel area is, for example, natural. The liquid amount of the functional liquid can be corrected before drying. As a result, in the subsequent drying process, the drying conditions can be the same in all the pixel regions, so that functional films having the same thickness can be formed.

  In this embodiment, the discharge device is described as an aspect that exists separately from the liquid amount measurement device, but the discharge device may be integrated with the liquid amount measurement device. In this way, the moving process of the substrate P can be omitted. In this case, the control device 10 includes a head driver that controls the ejection head 200 in the interface unit 18, and the CPU 11 is configured to perform ejection control of the functional liquid from the nozzle row 200 n via the head driver. .

  As described above, the present invention has been described using two embodiments. However, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the spirit of the present invention. Of course. Hereinafter, a modification will be described.

(First modification)
In the liquid amount measurement method of the above embodiment, in the short direction of the pixel region, the center position in the short direction, and two positions that are separated from the center position by a quarter or more of the width A in the short direction on both sides, The height of the liquid level is measured at these three positions, but it is needless to say that the present invention is not limited to this. As described above, the radius of curvature of the arc shape can be calculated from the three coordinate positions. Accordingly, the curvature radius can be calculated in the same manner at any three positions as long as the positions are on the line in the width A in the short direction.

  An example of this modification is shown in FIG. FIG. 12 shows a case where the position D1 is shifted from the center position of the width A in the lateral direction. The positions D2 and D3 are also arbitrary positions in the X-axis direction. Even at these three arbitrary positions, if the three points are located on the outline of the liquid level, the difference in height between the liquid levels “ΔH1, ΔH2” and the distance difference in the X-axis direction “ The radius of curvature R can be easily calculated from those coordinate positions determined by “ΔX1, ΔX2”.

  Furthermore, as a modification of the present modification, the three positions set on the line segment in the short direction do not necessarily have to be substantially the center position of the width B in the longitudinal direction. In the longitudinal width B, if the arc shape of the liquid surface is a position representing the amount of the functional liquid dropped on the pixel region, three positions on the short-side line segment at that position. You only have to set it.

(Other variations)
In the liquid amount measuring apparatus of the above embodiment, the position and shape data of the pixel region formed on the substrate P is acquired by the camera 20, but it is needless to say that the present invention is not limited to this. For example, the camera 20 may not be provided. When the position and shape of the pixel region are known in advance, the control device 10 may store the data in a memory such as a ROM. The CPU 11 may read and process the stored pixel area position and shape data. In this case, the acquisition unit 111 is not necessary. Furthermore, when the width B in the longitudinal direction and the width A in the lateral direction of the pixel region are known in advance, the calculation unit 112 is also unnecessary.

  In the manufacturing method of the above embodiment, the organic EL panel is described as an example of the electro-optical device. However, the present invention is not limited to this. For example, a color filter may be formed.

  In the above embodiment, the organic EL element is formed, and the functional layers applied and formed by droplet ejection are described as the hole injection layer and the light emitting layer. However, the present invention is not limited to this. Of course not. For example, when an electron injection layer is formed separately from the cathode, the electron injection layer may be a functional layer formed by discharging a functional liquid. Alternatively, when the light emitting layer also serves as the hole injection layer, only the light emitting layer may be a functional layer that is formed by application of functional liquid.

The schematic diagram which shows schematic structure of the liquid quantity measuring device as one Embodiment of this invention. The block diagram which shows schematic structure of a control apparatus. Explanatory drawing which showed a mode that a functional liquid was discharged to the to-be-discharged area | region formed in the board | substrate. FIG. 3 is a schematic diagram illustrating a configuration of a discharge head. It is a schematic diagram which shows the structure of the functional layer which an organic EL element has, (a) is a top view which showed the display part in which three pixels were located in a line, (b) is the schematic cross section, (c) is an organic EL element. The schematic cross section which showed a mode that the functional layer was apply | coated and formed by discharge of a functional liquid. The schematic diagram which shows the state by which predetermined amount of functional liquid was dripped. The processing flowchart of the liquid amount measuring method in 1st Embodiment. The schematic diagram which showed a mode that the height of the liquid level of the functional liquid dripped at the pixel area | region was measured. An example of the table used at the time of liquid amount measurement. Explanatory drawing which showed the locus | trajectory of the measuring instrument moved relatively with respect to a board | substrate. 9 is a process flowchart of a method for manufacturing an electro-optical device according to a second embodiment. Sectional drawing of the liquid level of the pixel area | region for demonstrating a 1st modification.

  DESCRIPTION OF SYMBOLS 10 ... Control apparatus, 11 ... CPU, 12 ... RAM, 13 ... ROM, 15 ... Table memory, 18 ... Interface part, 20 ... Camera, 30 ... Measuring instrument, 100 ... Liquid quantity measuring device, 101 ... Guide rail, 102 ... Guide rail 105 ... XY table 105a ... table 105b ... table 111 ... acquisition unit 112 ... calculation unit 113 ... measurement unit 114 ... measurement unit 200 ... discharge head 200n ... nozzle row.

Claims (15)

A liquid volume measuring method for measuring a liquid volume of the dropped liquid droplets with respect to a discharge target area of the liquid droplets formed so that one direction has a long longitudinal direction on a substrate surface,
At three different positions on the line segment along the short direction perpendicular to the longitudinal direction of the ejection target area, two other positions with reference to the liquid level height of the droplet at one of the three positions A measuring step for measuring the liquid level of the droplet at one position;
From the measured liquid level height of the droplet at the other two positions and the three positions, the radius of curvature of the arc approximating the liquid level shape of the droplet along the short direction is calculated, A measurement step of measuring the liquid volume of the droplet from the calculated radius of curvature;
A liquid volume measuring method comprising: The liquid amount measuring method according to claim 1,
In the measuring step, the position of the line segment along the short direction is set as a substantially central position in the longitudinal direction. It is the liquid quantity measuring method of Claim 1 or 2, Comprising:
In the measuring step, the one position is set to a substantially central position in a short direction of the discharge area. A liquid amount measuring method according to any one of claims 1 to 3,
In the measuring step, the other two positions are set to positions that are separated from a center position in the short direction by a quarter or more of a width in the short direction of the discharge area. . A liquid amount measuring method according to any one of claims 1 to 4, wherein
In the measuring step, the liquid volume of the droplet is measured from the calculated curvature radius using a table in which the correspondence between the liquid volume of the droplet and the radius of curvature is predetermined according to the shape of the discharge area. A liquid amount measuring method characterized by: A liquid amount measuring method according to any one of claims 1 to 5,
An acquisition step for acquiring information on the shape and the position on the substrate surface for the ejection region;
A calculation step of calculating the three positions for the discharge region using the information on the shape and the position;
A liquid volume measuring method comprising: The liquid amount measuring method according to claim 6,
The liquid volume measuring method characterized in that the acquiring step acquires information on the shape and the position of the discharged region by optically reading the discharged region formed on the substrate surface. A liquid volume measuring device for measuring a liquid volume of a dropped liquid droplet on a discharge target area of a liquid droplet formed in a region having a long longitudinal direction on a substrate surface,
Measuring means for measuring the liquid surface height of the droplet;
At three different positions on the line segment along the short direction perpendicular to the longitudinal direction of the discharge target region, the liquid level height of the droplet at one of the three positions is used as a reference. A measuring unit for measuring the liquid level height of the droplet at two positions using the measuring means;
From the measured liquid level height of the droplet at the other two positions and the three positions, the radius of curvature of the arc approximating the liquid level shape of the droplet along the short direction is calculated, A measuring unit for measuring the liquid volume of the droplet from the calculated radius of curvature;
A liquid quantity measuring device comprising: The liquid amount measuring device according to claim 8,
Moving means for moving the measuring means relative to the substrate surface in an in-plane direction;
An acquisition unit that acquires information on the shape of the discharge region and the position on the substrate surface;
Using the acquired information on the shape and the position, a calculation unit that calculates the three positions;
With
The liquid measuring device is characterized in that the measuring unit moves to the calculated three positions using the moving means and measures. The liquid amount measuring device according to claim 9,
Comprising a reading means for optically reading the discharge area formed on the substrate surface;
The acquisition unit acquires information on the shape and the position of the discharge target region by reading the discharge target region using the reading unit. It is a liquid quantity measuring device according to any one of claims 8 to 10,
The liquid measuring device, wherein the measurement unit sets the one position as a substantially central position in a short direction of the discharge area. The liquid volume measuring device according to any one of claims 8 to 11,
The liquid measuring device, wherein the measurement unit sets the other two positions to a position separated from a central position in the short direction by a quarter or more of a width in the short direction of the discharge area. . The liquid volume measuring device according to any one of claims 8 to 12,
The measurement unit measures the liquid volume of the droplet from the calculated curvature radius using a table in which a correspondence relationship between the liquid volume of the droplet and the radius of curvature is determined in accordance with the shape of the discharge target region. A liquid quantity measuring device characterized by: A method of manufacturing an electro-optical device in which a display element is formed by dropping a predetermined amount of a droplet onto a discharge target region of a droplet formed on a substrate surface so that one direction has a long longitudinal direction. There,
A dropping step of dropping the droplets onto the discharge region by discharging the droplets onto the discharge region using a discharge device;
A measuring step of measuring the liquid amount of the dropped liquid droplet using the liquid amount measuring method according to any one of claims 1 to 7,
A correction step of correcting the discharge amount of the discharge device based on the measured liquid amount of the droplet so that the drop amount of the droplet discharged by the discharge device becomes the predetermined amount;
A method for manufacturing an electro-optical device. A method of manufacturing an electro-optical device in which a display element is formed by dropping a predetermined amount of a droplet onto a discharge target region of a droplet formed on a substrate surface so that one direction has a long longitudinal direction. There,
A dropping step of dropping the droplets onto the discharge region by discharging the droplets onto the discharge region using a discharge device;
A measuring step of measuring the liquid amount of the dropped liquid droplet using the liquid amount measuring device according to any one of claims 8 to 13,
A correction step of correcting the discharge amount of the discharge device based on the measured liquid amount of the droplet so that the drop amount of the droplet discharged by the discharge device becomes the predetermined amount;
A method for manufacturing an electro-optical device.

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