Distortion aberration correction processing device, distortion aberration correction method and storage medium

Abstract

The present invention provides a distortion correction processing device, which can perform distortion correction with high precision even when the optical axis of an imaging device is tilted relative to the surface of a measurement object. A storage unit stores distortion correction information for each of a plurality of segments on an image plane of the imaging device divided by a plurality of boundary lines radially extending from a reference point, each of which represents the relationship between a coordinate correction rate for correcting coordinates on the image plane and a distance from the reference point. The processing unit selects at least one segment from the plurality of segments according to the coordinates of a correction target part in the image plane, determines the coordinate correction rate according to the distortion correction information of the selected segment and the distance from the reference point to the correction target part, and corrects the coordinates of the correction target part according to the determined coordinate correction rate.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2020-178944 filed on October 26, 2020. The entire contents of the Japanese Patent Application are incorporated herein by reference. Technical Field

[0002] The invention relates to a distortion aberration correction processing device, a distortion aberration correction method and a storage medium. Background Art

[0003] In an inkjet device that drips ink from an inkjet head onto an object to draw, a laser processing device that makes a laser beam incident on an object to perform drilling, and a laser annealing device that makes a laser beam incident on a semiconductor substrate as an object to perform annealing, alignment marks provided on the object are detected to position the object. In this case, the position of the alignment mark is detected by performing image processing on an image captured with the alignment mark.

[0004] In order to detect the position of the alignment mark with high precision, it is preferable to correct the distortion aberration of the lens (for example, the following patent document 1). In the distortion aberration correction method disclosed in patent document 1, a five-dimensional polynomial correction formula is set as a function to adjust the distance (image height) from the origin of the image plane to the distorted image to the distance before distortion. Using this polynomial correction formula, the distance after distortion is corrected to the distance before distortion.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2001-133223

[0006] If the optical axis of the imaging device is tilted relative to the surface of the object to be measured, the amount of distortion to be corrected will change depending on the position in the circumferential direction centered on the origin of the image plane. However, in the correction method disclosed in Patent Document 1, the distortion is corrected only by the distance from the origin of the image plane, so it is impossible to correct the distortion aberration with high accuracy when the optical axis of the imaging device is tilted. Summary of the invention

[0007] An object of the present invention is to provide a distortion correction processing device, a distortion correction method, and a storage medium capable of performing distortion correction with high accuracy even when the optical axis of an imaging device is tilted relative to the surface of a measurement object.

[0008] According to one aspect of the present invention, there is provided a distortion aberration correction processing device comprising:

[0009] a storage unit storing distortion correction information for each of a plurality of segments on an image plane of an imaging device divided by a plurality of boundary lines radially extending from a reference point, the distortion correction information indicating a relationship between a coordinate correction rate for correcting coordinates on the image plane and a distance from the reference point; and

[0010] A processing unit selects at least one segment from the plurality of segments according to the coordinates of the correction object part in the image plane, determines a coordinate correction rate according to the distortion aberration correction information of the selected segment and the distance from the reference point to the correction object part, and corrects the coordinates of the correction object part according to the determined coordinate correction rate.

[0011] According to another aspect of the present invention, a method for correcting distortion aberration is provided, which comprises the following steps:

[0012] The object to be measured is photographed using an imaging device, wherein distortion correction information for each of a plurality of segments divided by a plurality of boundary lines radially extending from a reference point within an image plane of the imaging device is known, and the distortion correction information indicates a relationship between a coordinate correction rate for correcting coordinates within an image and a distance from the reference point,

[0013] determining a correction target portion in the image plane for which coordinate correction is to be performed,

[0014] selecting at least one segment from the plurality of segments according to the position of the correction target part in the image plane,

[0015] determining a coordinate correction rate based on the distortion correction information of the selected segment and the distance from the reference point to the correction target site,

[0016] The coordinates of the correction target site are corrected according to the determined coordinate correction ratio.

[0017] According to another aspect of the present invention, there is provided a storage medium storing a program, wherein the program is executed by a computer to perform the following steps:

[0018] Acquiring an image of a measurement object captured by an imaging device, wherein distortion correction information of each of a plurality of segments divided by a plurality of boundary lines radially extending from a reference point within an image plane of the imaging device is known, and the distortion correction information indicates a relationship between a coordinate correction rate for correcting coordinates within the image and a distance from the reference point;

[0019] determining a correction target portion to be corrected from an image captured by the imaging device;

[0020] selecting at least one segment from the plurality of segments according to the coordinates of the calibration target part in the image plane;

[0021] determining a coordinate correction rate based on the distortion correction information of the selected segment and the distance from the reference point to the correction target site; and

[0022] The coordinates of the correction target site are corrected according to the determined coordinate correction ratio.

[0023] By dividing the image plane into a plurality of segments and correcting distortion using distortion correction information set for each segment, distortion correction can be performed with high accuracy even when the optical axis of the imaging device is tilted with respect to the surface of the object to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a block diagram of a distortion correction processing device according to an embodiment.

[0025] Figure 2 It is a diagram showing the content of distortion correction information.

[0026] Figure 3 This is a graph for explaining a method of correcting the coordinates of a correction target site in an image plane.

[0027] Figure 4 This is a flowchart showing the steps of correcting the coordinates of the correction target site in the image plane.

[0028] Figure 5 (A) is a diagram showing the distribution of images obtained by photographing a plurality of markers arranged in a matrix using a telecentric lens. Figure 5 (B) in the middle is a diagram showing the corrected coordinates of the marker calculated from the coordinates of the image of the marker using the method of this embodiment.

[0029] Figure 6 (A) and (B) are diagrams showing the image of the mark in the image plane when the optical axis of the imaging device is perpendicular to the surface of the object to be measured, assuming that there is no distortion aberration and assuming that there is distortion aberration, respectively. Figure 6 (C) shows the coordinate correction ratio D in the x direction relative to the diagonal direction of the image plane. x A graph showing the relationship between φ and the distance r from the center point of the image plane.

[0030] Figure 7 (A) and (B) are diagrams showing images of marks on the image plane when the optical axis of the imaging device is tilted relative to the surface of the object to be measured, assuming that there is no distortion aberration and assuming that there is distortion aberration, respectively. Figure 7In the middle (C), the coordinate correction rate D in the x direction for the diagonal direction of the image plane is plotted without distinguishing the four diagonal directions of the image plane. x A graph showing the relationship between the distance r from the center point of the image plane, Figure 7 The coordinate correction rate D in the x direction with respect to the diagonal direction of the image plane is plotted by dividing the segments Q1 to Q4. x A graph showing the relationship between φ and the distance r from the center point of the image plane.

[0031] Figure 8 (A) is a schematic front view of an inkjet drawing device according to another embodiment. Figure 8 The middle (B) is a diagram showing the positional relationship of the movable stage, the ink ejection unit, and the imaging device in a plan view.

[0032] Fig. 9 This is a flowchart showing the steps of drawing using an inkjet drawing device.

[0033] In the figure: 10-distortion aberration correction processing device, 11-input / output interface unit, 12-processing unit, 13-storage unit, 14-program, 15-distortion aberration correction information, 20-inkjet drawing device, 22-base, 23-support component, 24-moving mechanism, 24X-X direction moving mechanism, 24Y-Y direction moving mechanism, 25-movable workbench, 30-ink ejection unit, 32-nozzle, 40-camera device, 41-image plane of the camera device, 50-control device, 80-substrate, 81-alignment mark. DETAILED DESCRIPTION

[0034] refer to Figures 1 to 9 A distortion aberration correction processing device according to an embodiment will be described.

[0035] Figure 1 1 is a block diagram of a distortion correction processing device 10 according to an embodiment. The distortion correction processing device 10 according to this embodiment includes an input / output interface unit 11, a processing unit 12, and a storage unit 13. The processing unit 12 may be, for example, a computer. The storage unit 13 stores a program 14 for execution by the computer. The storage unit 13 also stores distortion correction information 15. The content of the distortion correction information 15 will be described later. Figure 2 As the storage unit 13, for example, an auxiliary memory such as a hard disk drive (HDD) or a solid state drive (SSD) can be used.

[0036] The processing unit 12 acquires image data from the camera device 40 via the input / output interface unit 11. The processing unit 12 performs image analysis to detect the coordinates of the image of the alignment mark in the image. The coordinates of the image are affected by the distortion aberration of the lens and deviate from the actual coordinates representing the position of the actual alignment mark. The processing unit 12 uses the distortion aberration correction information 15 stored in the storage unit 13 to correct the coordinates of the image, thereby reducing the error between the coordinates and the actual coordinates of the alignment mark. Thereafter, the corrected coordinates are transmitted to the control device 50 via the input / output interface unit 11. The control device 50 performs various processes based on the corrected coordinates of the alignment mark. The processing unit 12 and the control device 50 can also be implemented by a common computer. At this time, the processing unit 12 can transmit the corrected coordinates of the alignment mark to the control device 50 without passing through the input / output interface unit 11.

[0037] Figure 2 1 is a diagram showing the contents of the distortion correction information 15. In the imaging device 40 ( Figure 1 ) is defined on an image plane 41 with a reference point O as the origin. Object points within the field of view of the camera device 40 are transferred to the image plane 41. The image plane 41 is, for example, a square or a rectangle, and the reference point O is the center of the square or the rectangle. The x-axis and the y-axis are defined to be parallel to one side of the image plane 41.

[0038] The image plane 41 is divided into a plurality of segments Q1 to Q4 by a plurality of boundary lines BL extending radially from the reference point O. In the present embodiment, the line segments connecting the reference point O and the midpoints of the sides of the image plane 41 are used as the boundary lines BL. The four boundary lines BL correspond to the positive and negative parts of the x-axis and the positive and negative parts of the y-axis, and the segments Q1 to Q4 correspond to the first to fourth quadrants of the xy coordinate system, respectively.

[0039] Affected by the distortion of the lens, the image point P corresponding to a certain observation point 1 The position of the image point P is assumed to be without aberration. 0 The distortion aberration correction information 15 is used to correct the position deviation of the image point P 1 The coordinates of the image point P without aberration are obtained 0 The coordinate information of the coordinates includes the coordinate correction rate D in the x direction x and the coordinate correction rate D in the y direction y .

[0040] Next, a method for obtaining the distortion correction information 15 of the segment Q1 will be described. Figure 1) An observation object having a plurality of marks formed with known positions is photographed to acquire an image. The plurality of marks are, for example, grid points of a grid pattern. The observation object is moved until the image of the mark serving as the reference point of the observation object coincides with the reference point O of the image plane 41. For example, the image of the photographed mark can be analyzed to detect the position of the image of the mark, and the observation object is moved according to the detection result so that the image of the mark serving as the reference point coincides with the reference point O of the image plane 41. In order to improve the accuracy of coinciding the two, this step can be repeated multiple times.

[0041] By analyzing the obtained image, a plurality of image points located on the diagonal line of the segment Q1 with the reference point O as one end are extracted from the plurality of marked image points. One of the extracted image points is marked as P 1 . Will be with the image point P 1 The corresponding image point without aberration is marked as P 0 . By performing image analysis, the image point P is obtained. 1 The coordinates of the image point P 1 The corresponding image point P without aberration 0 The coordinates are marked as (x 0 ,y 0 ), the image point P 1 The coordinates are marked as (x 1 ,y 1 ). The coordinate correction rate D in the x direction is defined by the following formula: x and the coordinate correction rate D in the y direction y .

[0042] [Formula 1]

[0043]

[0044] Coordinate correction rate D in the x direction x is the image point P when there is no aberration 0 To the actual image point P 1 The displacement x in the x direction until 1 -x 0 From the reference point O to the image point P when there is no aberration 0 The length x in the x direction to 0 The ratio of the coordinate correction rate in the y direction D y is the image point P when there is no aberration 0 To the actual image point P 1 The displacement in the y direction to 1 -y 0 From the reference point O to the image point P when there is no aberration 0 The length y in the y direction to 0 Generally, the distortion of a lens is smaller at the center of the image plane and larger at the periphery. Therefore, the coordinate correction ratio Dx , D y Depends on the distance r from the reference point O.

[0045] From the reference point O to the actual image point P 1 The distance r to the horizontal axis and the coordinate correction rate D in the x direction are x The graph as the vertical axis is plotted with respect to a plurality of image points P on the diagonal line. 1 Determine an approximate curve that approximates the distribution of the plotted multiple points. Figure 2 As shown, for segment Q1, the coordinate correction rate D in the x direction x is defined as a function of the distance r. Similarly, the coordinate correction rate D in the y direction y is also defined as a function of the distance r. Thus, for segment Q1, distortion correction information 15 is obtained. Figure 2 In the graph of the distortion correction information 15 of the segment Q1 shown in FIG. 1 , the coordinate correction rate D in the x direction is represented by a thick solid line and a thin solid line, respectively. x and the coordinate correction rate D in the y direction y An example of.

[0046] The distortion correction information 15 can also be obtained for the other segments Q2 to Q4 using the same method. The obtained distortion correction information 15 is stored in the storage unit 13 ( Figure 1 ). In the case where the distortion aberration does not depend on the radial direction centered at the reference point O, the coordinate correction rate D x , D y The coordinate correction rate D is roughly the same between sections Q1 to Q4. However, in practice, due to various reasons, the coordinate correction rate D x , D y There is a deviation between the segments Q1 to Q4. The deviation may be caused, for example, by the optical axis of the imaging device 40 being tilted relative to the surface of the observation object.

[0047] Next, refer to Figure 3 and Figure 4 A method of correcting the coordinates of a certain site (hereinafter referred to as a correction target site) in the image plane 41 to coordinates without aberration will be described.

[0048] Figure 3 4 is a graph for explaining a method of correcting the coordinates of the correction target site Pt in the image plane 41 . Figure 4 4 is a flowchart showing the procedure for correcting the coordinates of the correction target site Pt in the image plane 41 .

[0049] First, the correction target part Pt in the image plane 41 is determined. The correction target part Pt is, for example, equivalent to the center point of the image of the alignment mark. Two segments are selected from the four segments Q1 to Q4 according to the position of the correction target part Pt (step S1). For example, two segments on both sides of the boundary line BL that divides the four segments Q1 to Q4 and that has the smallest angle with the direction from the reference point O toward the correction target part Pt are selected. Figure 3 In , the positive part of the y-axis corresponds to the boundary line BL that satisfies this condition. Two segments Q1 and Q2 on both sides of the positive part of the y-axis are selected.

[0050] Next, according to the distortion correction information 15 ( Figure 1 and Figure 2 ) The coordinate correction rate D of the segments Q1 and Q2 corresponding to the distance r from the reference point O to the correction target part Pt is x , D y The weighted average is performed to obtain the coordinate correction rate D at the position of the correction target part Pt. xt (r), D yt (r) (Step S2) For example, a weighted average is performed based on the angle between the direction from the reference point O toward the geometric center of the two selected segments Q1 and Q2 (corresponding to the diagonal direction of the segments Q1 and Q2) and the direction from the reference point O toward the correction target site Pt.

[0051] The angles formed by the direction from the reference point O toward the geometric centers of the two selected segments Q1 and Q2 and the direction from the reference point O toward the correction target site Pt are respectively denoted as θ 1 ,θ 2 When the coordinate correction rate D on the correction target part Pt is xt (r), D yt (r) is represented by the following formula.

[0052] [Formula 2]

[0053]

[0054] Among them, D x1 (r), D y1 (r) are the coordinate correction rates in the x direction and y direction obtained for segment Q1, D x2 (r), D y2 (r) are the coordinate correction rates in the x direction and the y direction respectively obtained for the segment Q2.

[0055] Next, based on the weighted average coordinate correction rate D at the correction target part Pt, xt , D ytThe coordinates of the correction target part Pt in the image plane are corrected (step S3). 1 ,y 1 ) and mark the corrected coordinates as (x 0 ,y 0 ), use the following formula to calculate the corrected coordinates.

[0056] [Formula 3]

[0057]

[0058] Next, refer to Figure 5 (A) and (B) illustrate the excellent effects of this embodiment.

[0059] Figure 5 (A) is a diagram showing the distribution of images obtained by photographing a plurality of markers arranged in a matrix using a telecentric lens. Figure 5 In (A), the deviation from the image of the marker without aberration to the actual image is magnified 100 times and shown. Figure 5 As can be seen in (A), barrel-shaped distortion occurs.

[0060] Figure 5 (B) is a diagram showing the coordinates of the image of the marker after correction calculated from the coordinates of the actual image of the marker using the method of this embodiment. Figure 5 In (B), the offset from the image of the marker without aberration to the image after coordinate correction is also shown magnified 100 times. Figure 5 As can be seen in (B), the distortion aberration has been corrected, resulting in a distribution close to the original matrix configuration.

[0061] In this way, by using the method of the above-described embodiment, it is possible to correct the distortion aberration of the lens so that the coordinates of the image of the mark are close to the coordinates when there is no aberration.

[0062] Next, refer to Figure 6 and Figure 7 The camera device 40 ( Figure 1 ) is explained below, the reason why distortion aberration can be corrected with high accuracy even when the optical axis of the image sensor is tilted relative to the surface of the object to be measured.

[0063] Figure 6 (A) and (B) in the figure respectively show the image of the mark in the image plane 41 when the optical axis of the imaging device 40 is perpendicular to the surface of the measurement object, assuming that there is no distortion aberration and assuming that there is distortion aberration. Figure 6 The horizontal axis and vertical axis of (A) and (B) represent the positions in the x-direction and y-direction, respectively. A plurality of marks are arranged at the grid points of the grid pattern. Figure 6 In (A) and (B), the image of the mark is represented by a circular mark painted black.

[0064] Assuming there is no distortion, Figure 6 As shown in (A), the positions of the images of the multiple markers coincide with the grid points of the square grid. Assuming that there is distortion, Figure 6 As shown in (B), the position of the marked image deviates from the grid point. Figure 6 In (B), it is assumed that barrel-shaped distortion that is significantly larger than the distortion of a normal lens occurs.

[0065] Figure 6 In the middle (C), the coordinate correction rate D in the x direction of the diagonal direction of the image plane is plotted without distinguishing the four diagonal directions. x A graph showing the relationship between θ and the distance r from the center point of the image plane. Since the distortion aberration has a low dependence on the rotation direction about the center point of the image plane, the multiple measurement points plotted in the four diagonal directions can be accurately approximated by a single approximation curve.

[0066] Figure 7 (A) and (B) in the middle are diagrams showing the image of the mark in the image plane 41 when the optical axis of the imaging device 40 is tilted with respect to the surface of the measurement object, assuming that there is no distortion aberration and assuming that there is distortion aberration, respectively. Figure 7 The horizontal axis and vertical axis of (A) and (B) represent the positions in the x-direction and y-direction, respectively. A plurality of marks are arranged at the grid points of the grid pattern. Figure 7 In (A) and (B), the image of the mark is represented by a circular mark painted black.

[0067] Since the optical axis of the camera device 40 is tilted, Figure 7 As shown in (A), even if there is no distortion aberration, the position of the image of the mark deviates from the grid point. Since there is no distortion aberration, the image of the straight line on the measured object also becomes a straight line in the image plane. For example, when the outer periphery of the distribution area of ​​the plurality of marks is a square, the outer periphery of the distribution area of ​​the image of the mark becomes a trapezoid in the image plane 41.

[0068] If we assume Figure 7 The distribution of the image of the marker shown in (A) is generated by Figure 6 The same aberration as the distortion aberration shown in (B) is Figure 7 As shown in (B) in the middle, the distribution area of ​​the image of the mark when distortion aberration is assumed to be present becomes a shape that is a combination of a trapezoid and a barrel.

[0069] Figure 7In the middle (C), the coordinate correction rate D in the x direction for the diagonal direction of the image plane 41 is plotted without distinguishing the four diagonal directions of the image plane 41. x The graph is a graph showing the relationship between the distance r from the center point of the image plane 41. The magnitude and direction of the distortion aberration are different between the diagonal directions, so Figure 6 Compared with the case shown in (C), the plotted measurement points are distributed in a wider range in the vertical axis direction. Even if an approximate curve is set for this distribution, the error between the coordinate correction rate obtained from the approximate curve and the coordinate correction rate at each measurement point is large.

[0070] Figure 7 In the middle (D), the coordinate correction rate D in the x direction with respect to the diagonal direction of the image plane 41 is plotted by dividing the segments Q1 to Q4. x The relationship between the square mark, triangle mark and circle mark in the graph are the measurement points located on the diagonal lines of the segments Q2, Q3 and Q4, respectively. In addition, the coordinate correction ratio is calculated for the multiple measurement points of the segment Q1, but Figure 7 The measurement point is not shown in (D).

[0071] Figure 7 The thin dashed line, thin solid line, thick dashed line, and thick solid line in the graph (D) are approximate curves that approximate the distribution of the measurement points of the coordinate correction rate in the x direction of the segments Q1 to Q4. If one segment is focused on, the error between the coordinate correction rate obtained from the approximate curve and the coordinate correction rate at multiple measurement points is small.

[0072] When the optical axis of the imaging device 40 is inclined relative to the surface of the object to be measured, Figure 7 If the coordinates of the correction target part are corrected by using an approximate curve shown in (C) in FIG. 1 , the error between the corrected coordinates and the coordinates without aberration will become larger depending on the position of the correction target part. In contrast, in the present embodiment, in step S1 ( Figure 4 ), select Figure 7 Among the four approximate curves shown in (D), two approximate curves more accurately reflect the coordinate correction rate at the correction target site.

[0073] Furthermore, in step S2 ( Figure 4 ), the coordinate correction rates obtained from the two approximate curves are weighted averaged according to the degree of reflecting the coordinate correction rate on the calibration target part. Therefore, even when the optical axis of the imaging device 40 is inclined relative to the surface of the measurement target object, the coordinate correction can be performed using a coordinate correction rate close to the actual coordinate correction rate on the calibration target part. Therefore, the accuracy of coordinate correction can be improved.

[0074] Next, a modification of the above-described embodiment will be described.

[0075] In the above embodiment, the image plane 41 ( Figure 2 ) is divided into four sections Q1 to Q4, but the number of sections is not limited to four. The number of sections can be two or more. For example, Figure 7 In the example shown in (D), the approximate curves of segments Q1 and Q4 are similar to each other, and the approximate curves of segments Q2 and Q3 are similar to each other. Therefore, even if segments Q1 and Q4 are combined into one segment and segments Q2 and Q3 are combined into one segment, it is possible to maintain a high coordinate correction accuracy to a certain extent.

[0076] Furthermore, in the above embodiment, for the plurality of image points P on each diagonal line of the four segments Q1 to Q4 1 ( Figure 2 ) The coordinate correction ratio is calculated, and an approximate curve is set based on the coordinate correction ratio. 1 , is not limited to the diagonal line, but can also consider other image points P in the segment 1 An approximate curve is set based on the coordinate correction rate.

[0077] For example, for a plurality of image points P in a region between two radial directions from the reference point O toward a segment, 1 The coordinate correction ratio can also be obtained. At this time, in order to set the multiple image points P in the segment that are strongly reflected 1 The two radial directions are preferably set in such a way that the area sandwiched between the two radial directions includes the geometric center of the segment.

[0078] Furthermore, in the above embodiment, in step S1 ( Figure 4 ), two segments on both sides of the boundary line BL that has the smallest angle with the direction from the reference point O toward the correction target part Pt among the four boundary lines BL are selected. Alternatively, two segments that approximate the coordinate correction rate on the correction target part Pt with high accuracy may be selected.

[0079] For example, in Figure 7 In the example shown in (D), the approximate curve of segment Q1 and the approximate curve of segment Q4 show the same tendency with respect to the change of distance r. This means that when the correction target part Pt is located in segment Q1 or segment Q4, the coordinate correction rate on the correction target part Pt is approximated with high accuracy in segment Q1 and segment Q4. Therefore, when the correction target part Pt is located in segment Q1 or segment Q4, in step S1( Figure 4), it is preferred to select segment Q1 and segment Q4 as the two segments. For the same reason, when the correction target part Pt is located in segment Q2 or segment Q3, in step S1 ( Figure 4 ), segment Q2 and segment Q3 are preferably selected as the two segments.

[0080] Furthermore, in the above embodiment, in step S1 ( Figure 4 ), but one segment can also be selected. For example, at angle θ 1 ( Figure 3 ) is 0° or small enough, only segment Q1 can be selected. 1 The size of the determines whether to select one segment or two segments.

[0081] Next, refer to Figure 8 and Fig. 9 The inkjet drawing device according to another embodiment is described. The inkjet drawing device according to this embodiment is equipped with a Figure 1 to Figure 4 The distortion aberration correction device of the embodiment shown.

[0082] Figure 8 (A) is a schematic front view of the inkjet drawing device 20. A movable table 25 is supported on the base 22 via a moving mechanism 24. An xyz orthogonal coordinate system is defined in which the x-axis and the y-axis are oriented in the horizontal direction and the z-axis is oriented in the vertical direction downward. The control device 50 controls the moving mechanism 24 to move the movable table 25 in both the x-direction and the y-direction. As the moving mechanism 24, for example, an XY stage including an X-direction moving mechanism 24X and a Y-direction moving mechanism 24Y can be used.

[0083] A substrate 80 to be drawn is held on the upper surface of the movable stage 25. The substrate 80 is fixed to the movable stage 25 by, for example, a vacuum chuck. An ink ejection unit 30 and an imaging device 40 are supported above the movable stage 25 by, for example, a gate-shaped support member 23.

[0084] The imaging device 40 captures an image of the upper surface of the substrate 80. More specifically, the imaging device 40 captures an image of a region within the field angle range of the imaging device 40 on the upper surface of the substrate 80. The image acquired by the imaging device 40 is input to the distortion correction processing device 10.

[0085] The control device 50 receives the position information of the substrate 80 from the distortion correction processing device 10. The control device 50 controls the moving mechanism 24 and the ink ejection unit 30 based on the position information, so that the ink is dropped on a predetermined position on the surface of the substrate 80. Thus, a film of ink of a predetermined shape is formed on the surface of the substrate 80.

[0086] Figure 8 (B) is a diagram showing the positional relationship of the movable stage 25, the ink ejection unit 30, and the imaging device 40 when viewed from above. A substrate 80 is held on the upper surface of the movable stage 25. The ink ejection unit 30 and the imaging device 40 are supported above the substrate 80. A plurality of nozzles 32 are provided on the surface of the ink ejection unit 30 facing the substrate 80. The control device 50 controls the moving mechanism 24 to move the movable stage 25 in the x-direction and the y-direction, and controls the ejection of ink from each nozzle 32 of the ink ejection unit 30.

[0087] Alignment marks 81 are formed at four corners of the substrate 80 . The control device 50 operates the moving mechanism 24 so that each alignment mark 81 is arranged within the field angle range of the imaging device 40 , so that the imaging device 40 can capture an image of the alignment mark 81 .

[0088] Fig. 9 Flowchart showing the steps of drawing using an inkjet drawing device. First, the control device 50 operates the moving mechanism 24 to move an alignment mark 81 to within the field of view of the camera device 40 (step S11). Thereafter, the camera device 40 photographs the alignment mark 81 (step S12). The photographed image data is input to the distortion correction processing device 10. The distortion correction processing device 10 analyzes the image of the alignment mark 81, thereby detecting the coordinates of the image of the alignment mark 81 in the image plane (step S13). The detection of the coordinates of the image of the alignment mark 81 can use a known algorithm (for example, pattern matching, etc.).

[0089] The distortion aberration correction processing device 10 performs the Figure 4 The coordinates of the image of the alignment mark 81 are corrected according to the steps of the embodiment shown (step S14). The processing from step S11 to step S14 is repeated until the coordinates of all alignment marks 81 are corrected (step S15).

[0090] When the coordinate correction of all alignment marks 81 is completed, the distortion correction processing device 10 sends a signal to the control device 50 ( Figure 8 The control device 50 transmits the corrected coordinates of the image of the alignment mark 81 (step S16). The control device 50 executes the drawing process based on the corrected coordinates of the image of the alignment mark 81 (step S17).

[0091] Next, the excellent effects of this embodiment will be described.

[0092] Since the inkjet drawing device according to this embodiment is equipped with Figure 1 to Figure 4The distortion correction processing device 10 shown can therefore accurately measure the position of the alignment mark 81. In particular, even when the optical axis of the imaging device 40 is tilted relative to the surface of the substrate 80, the measurement accuracy of the position of the alignment mark 81 can be suppressed from decreasing.

[0093] Next, Figure 8 and Fig. 9 A modification of the embodiment shown will be described. Figure 8 and Fig. 9 In the embodiment shown, based on Figure 1 to Figure 4 The distortion correction processing device 10 of the embodiment shown is mounted on an inkjet drawing device, but based on Figure 1 to Figure 4 The distortion correction processing device 10 of the embodiment shown may also be mounted on other devices, for example, a laser processing device that performs drilling processing by irradiating a laser beam onto an object, a laser annealing device that performs annealing by irradiating a laser beam onto a semiconductor substrate as an object, etc.

[0094] The above embodiments are examples. Of course, parts of the structures shown in different embodiments can be replaced or combined. The same effects based on the same structure in multiple embodiments are not mentioned one by one in each embodiment. Moreover, the present invention is not limited to the above embodiments. For example, various changes, improvements, combinations, etc. can be made, which is obvious to those skilled in the art.

Claims

1. A distortion aberration correction processing device, characterized in that: have: a storage unit storing distortion correction information for each of a plurality of segments on an image plane of an imaging device divided by a plurality of boundary lines radially extending from a reference point, the distortion correction information indicating a relationship between a coordinate correction rate for correcting coordinates on the image plane and a distance from the reference point; and A processing unit selects two segments on both sides of the boundary line that has the smallest angle with the direction from the reference point toward the correction object part among the multiple boundary lines, performs weighted averaging of coordinate correction rates of the distortion aberration correction information of the two selected segments according to the angles formed between the directions from the reference point toward the geometric centers of each of the two selected segments and the direction from the reference point toward the correction object part, and corrects the coordinates of the correction object part according to the weighted average coordinate correction rates.

2. The distortion correction processing device according to claim 1, characterized in that: The shape of the image plane is square or rectangular, The reference point is located at the center of the image plane. The plurality of boundary lines are four line segments connecting the center of the image plane and the midpoints of four sides.

3. A distortion aberration correction method, characterized in that: The following steps are required: The object to be measured is photographed using an imaging device, wherein distortion correction information for each of a plurality of segments divided by a plurality of boundary lines radially extending from a reference point within an image plane of the imaging device is known, and the distortion correction information indicates a relationship between a coordinate correction rate for correcting coordinates within an image and a distance from the reference point, determining a correction target portion in the image plane for which coordinate correction is to be performed, selecting two segments on both sides of a boundary line having the smallest angle with the direction from the reference point toward the calibration target site among the plurality of boundary lines, weighted averaging of the coordinate correction rates of the distortion correction information of the two selected segments according to the angle between the direction from the reference point toward the geometric center of each of the two selected segments and the direction from the reference point toward the correction target site; The coordinates of the correction target site are corrected according to the weighted average coordinate correction rate.

4. A storage medium storing a program, characterized in that: The program is executed by a computer to perform the following steps: Acquiring an image of a measurement object captured by an imaging device, wherein distortion correction information of each of a plurality of segments divided by a plurality of boundary lines radially extending from a reference point within an image plane of the imaging device is known, and the distortion correction information indicates a relationship between a coordinate correction rate for correcting coordinates within the image and a distance from the reference point; determining a correction target portion to be corrected from an image captured by the imaging device; selecting two segments on both sides of a boundary line having the smallest angle with the direction from the reference point toward the calibration target part among the plurality of boundary lines; Taking a weighted average of the coordinate correction rates of the distortion correction information of the two selected segments according to the angle between the direction from the reference point toward the geometric center of each of the two selected segments and the direction from the reference point toward the correction target portion; and The coordinates of the correction target site are corrected according to the weighted average coordinate correction rate.

Images