KR20220055410A - Apparatus for correcting distortion, method for correcting distortion, and program - Google Patents

Abstract

Provided is an apparatus for processing correction of distortion, which can perform correction of distortion on a surface of an object to be measured with high precision even though an optical axis of a photographing device is inclined. The apparatus of the present invention comprises: a memory unit storing a coordinate correction rate for correcting coordinates on an image plane and distortion correction information indicating relations of a distance from a reference point for each of a plurality of divisions defined by a plurality of boundaries extended radially from the reference point of the image plane of the photographing device; and a processing unit selecting at least one division from the plurality of the divisions, based on coordinates on an image plane of a site to be corrected, determining a coordinate correction rate based on the distortion correction information on the selected division and a distance from the reference point to the site to be corrected, and correcting coordinates of the site to be corrected based on the determined coordinate correction rate.

Description

Distortion aberration correction processing apparatus, distortion correction method, and program

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

The present invention relates to a distortion aberration correction processing apparatus, a distortion aberration correction method, and a program.

In an inkjet apparatus for drawing ink by striking an object from an inkjet head, a laser processing apparatus for performing punching processing by injecting a laser beam onto an object, a laser annealing apparatus for annealing by injecting a laser beam onto a semiconductor substrate as an object, etc. Positioning of the object is performed by detecting the provided alignment marks. At this time, the position of the alignment mark is detected by performing image processing of the image on which the alignment mark was stamped.

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

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-133223

When the optical axis of the imaging device becomes oblique with respect to the surface of the measurement object (slanted surface), the amount to be corrected for distortion changes according to the position in the circumferential direction with respect to the origin of the image plane. However, in the correction method disclosed in Patent Document 1, since distortion is corrected only in accordance with the distance from the origin of the image plane, it is impossible to correct the distortion with high precision when the optical axis of the imaging device is slanted.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a distortion aberration correction processing apparatus, a distortion aberration correction method, and a program capable of performing distortion aberration correction with high precision even in a state where the optical axis of an imaging device is slanted with respect to the surface of a measurement object.

According to one aspect of the present invention,

Distortion representing the relationship between the coordinate correction rate for correcting the coordinates on the image plane and the distance from the reference point for each of a plurality of divisions divided by a plurality of boundary lines extending radially from the reference point of the image plane of the image pickup device a memory unit storing aberration correction information;

At least one section is selected from the plurality of sections based on the coordinates of the section to be corrected in the image plane, and the distortion aberration correction information for the selected section and the distance from the reference point to the section to be corrected are obtained. There is provided a distortion aberration correction processing apparatus having a processing unit that determines a coordinate correction rate based on the determined coordinate correction rate and corrects the coordinates of the correction target point based on the determined coordinate correction rate.

According to another aspect of the present invention,

Distortion aberration correction indicating a relationship between a coordinate correction rate for correcting coordinates in an image and a distance from the reference point for each of a plurality of divisions separated by a plurality of boundary lines extending radially from a reference point in the image plane of the imaging device Using an imaging device for which information is already known, the measurement object is imaged,

Determining a correction target location to correct the coordinates in the image plane,

selecting at least one section from the plurality of sections based on the position of the correction target point in the image plane;

determining a coordinate correction rate based on the distortion aberration correction information for the selected section and the distance from the reference point to the correction target point,

There is provided a distortion aberration correction method for correcting the coordinates of the correction target point based on the determined coordinate correction rate.

According to another aspect of the present invention,

Distortion aberration correction indicating a relationship between a coordinate correction rate for correcting coordinates in an image and a distance from the reference point for each of a plurality of divisions separated by a plurality of boundary lines extending radially from a reference point in the image plane of the imaging device a procedure for acquiring an image of a measurement target imaged using an imaging device for which information is already known;

a procedure for determining a correction target point to be corrected from the image captured by the image pickup device;

a procedure of selecting at least one section from the plurality of sections based on the coordinates in the image plane of the point to be corrected;

a procedure of determining a coordinate correction rate based on the distortion aberration correction information for the selected section and the distance from the reference point to the correction target point;

There is provided a computer-readable recording medium in which a program for executing a procedure for correcting the coordinates of the location to be corrected based on the determined coordinate correction rate is recorded.

The image plane is divided into a plurality of sections, and distortion is corrected using distortion aberration correction information set for each section, so that the distortion aberration is accurately achieved even when the optical axis of the imaging device is slanted with respect to the surface of the object to be measured. It is possible to make corrections.

1 is a block diagram of a distortion aberration correction processing apparatus according to an embodiment.
Fig. 2 is a diagram showing the contents of distortion aberration correction information.
3 is a graph for explaining a method of correcting the coordinates in the image plane of the correction target point.
Fig. 4 is a flowchart showing a procedure for correcting the coordinates in the image plane of the part to be corrected.
5A of FIG. 5 is a diagram showing the distribution of images captured by a telecentric lens for a plurality of marks arranged in a matrix form, and FIG. 5B is a diagram showing the image coordinates of the marks according to the present embodiment It is a figure which shows the coordinates after correction|amendment of the mark calculated using the method.
6A and 6B are diagrams showing images of marks in the image plane when it is assumed that there is no distortion aberration and when the optical axis of the imaging device is perpendicular to the surface of the measurement object, respectively; 6C is a graph plotting the relationship between the coordinate correction rate D _x in the x direction with respect to the diagonal direction of the image plane and the distance r from the center point of the image plane.
7A and 7B of FIG. 7 show images of marks in the image plane when it is assumed that there is no distortion aberration and when the optical axis of the imaging device can be inclined with respect to the surface of the measurement object, respectively. 7C of FIG. 7 shows the relationship between the coordinate correction rate D _x in the x direction with respect to the diagonal direction of the image plane and the distance r from the center point of the image plane without distinguishing the four diagonal directions of the image plane. It is a plotted graph, and 7D of FIG. 7 plots the relationship between the coordinate correction rate D _x in the x direction with respect to the diagonal direction of the image plane and the distance r from the center point of the image plane by distinguishing each of the sections Q1 to Q4. It is one graph.
Fig. 8A is a schematic front view of an inkjet drawing apparatus according to another embodiment, and Fig. 8B is a diagram showing the positional relationship of the movable table, the ink ejection unit, and the imaging device in a plan view. am.
9 is a flowchart showing a procedure for performing drawing with an inkjet drawing apparatus.

A distortion aberration correction processing apparatus according to an embodiment will be described with reference to FIGS. 1 to 9 .

1 is a block diagram of a distortion aberration correction processing apparatus 10 according to an embodiment. The distortion aberration correction processing apparatus 10 according to the present embodiment includes an input/output interface unit 11 , a processing unit 12 , and a storage unit 13 . For the processing unit 12, for example, a computer is used. In the storage unit 13, a program 14 to be executed by the computer is stored. The storage unit 13 also stores distortion aberration correction information 15 . The contents of the distortion aberration correction information 15 will be described later with reference to FIG. 2 . As the storage unit 13, for example, an auxiliary storage device such as a hard disk drive (HDD) or a solid state drive (SSD) is used.

The processing unit 12 acquires image data from the imaging device 40 via the input/output interface unit 11 . The processing unit 12 detects the coordinates of the image of the alignment mark in the image by performing image analysis. The coordinates of this image are deviated from the real coordinates indicating the actual position of the alignment mark due to the influence of the distortion aberration of the lens. The processing unit 12 uses the distortion aberration correction information 15 stored in the storage unit 13 to correct the coordinates of the image and reduce the error with the real 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 coordinates after correction of the alignment mark. The processing unit 12 and the control device 50 may be realized by a common computer. In this case, the processing unit 12 transmits the coordinates after the alignment mark correction to the control device 50 without interposing the input/output interface unit 11 .

2 is a diagram showing the contents of the distortion aberration correction information 15 . On the image plane 41 of the imaging device 40 (FIG. 1), an xy orthogonal coordinate system having a reference point O as an origin is defined. An object point within the imaging range (photographing range) of the imaging device 40 is transferred to the image plane 41 . The image plane 41 is, for example, a square or rectangle, and the reference point O is the center of the square or rectangle. The x-axis and the y-axis are defined to be parallel to any one side of the image plane 41 .

The image plane 41 is divided into a plurality of divisions Q1 to Q4 by a plurality of boundary lines BL extending radially from the reference point O. In this embodiment, a line segment connecting the reference point O and the midpoint of each side of the image plane 41 is employed as the boundary line BL. The four boundary lines BL correspond to the positive and negative portions of the x-axis, and the positive and negative portions of the y-axis, and the divisions Q1 to Q4 are, respectively, in the first quadrant of the xy coordinate system. It corresponds to the fourth quadrant.

Due to the influence of the distortion aberration of the lens, the position of the image point P ₁ corresponding to a certain observation point is deviated from the position of the image point P ₀ when it is assumed that the lens has no aberration. The distortion aberration correction information 15 is information for correcting the coordinates of the image point P ₁ to obtain the coordinates of the image point P ₀ at the time of aberration-free, and the coordinate correction rate D in the _x direction and the coordinate correction rate in the y direction. Includes coordinate correction rate D _y .

Next, a method of calculating the distortion aberration correction information 15 for the section Q1 will be described. An image is acquired by imaging an observation object on which a plurality of marks of known positions are formed with the imaging device 40 (FIG. 1). The plurality of marks are, for example, grid-like grid points. The object to be observed is moved until the image of the mark serving as the reference point of the object to be observed coincides with the reference point O of the image plane 41 . For example, by analyzing the image taken of the mark, detecting the position of the image of the mark, and moving the object to be observed based on the detection result, the image of the mark serving as the reference point is matched with the reference point O of the image plane 41 can In order to increase the accuracy of matching between the two, this procedure may be repeated a plurality of times.

By analyzing the obtained image, a plurality of image points located on the diagonal of the section Q1 having the reference point O as one end are extracted from the image points of the plurality of marks. One image point among the plurality of extracted image points is denoted as P ₁ . The aberration image point corresponding to the image point P ₁ is denoted as P ₀ . By performing image analysis, the coordinates of the image point P ₁ are obtained. The coordinates of the image point P ₀ during aberration corresponding to the image point P ₁ are expressed as (x ₀ , y ₀ ), and the coordinates of the image point P ₁ are expressed as (x ₁ , y ₁ ). The coordinate correction rate D _x in the x direction and the coordinate correction rate D _y in the y direction are defined by the following equations.

[Equation 1]

The coordinate correction rate D _x in the x-direction is the x-direction length from the reference point O to the image point P ₀ at the time of aberration x the x-direction from the image point P ₀ at the time of aberration to the actual image point P ₁ for x ₀ is the ratio of displacement x ₁ -x ₀ . The coordinate correction rate D _y in the y direction is the length y in the y direction from the reference point O to the image point P ₀ at the time of aberration in the y direction from the image point P ₀ at the time of aberration to the actual image point P _{1 .} is the ratio of displacement y ₁ -y ₀ of . In general, the distortion aberration of a lens is small at the center of the image plane and large at the periphery. For this reason, the coordinate correction rates D _x , D _y depend on the distance r from the reference point O.

The measurement results for a plurality of image points P ₁ on a diagonal are plotted on a graph in which the horizontal axis is the distance r from the reference point O to the actual image point P ₁ and the vertical axis is the coordinate correction rate D _x in the x direction. An approximation curve approximating the distribution of a plurality of plotted points is determined. As a result, as shown in Fig. 2 , the coordinate correction rate D _x in the x direction is defined as a function of the distance r with respect to the division Q1. Similarly, the coordinate correction rate D _y in the y direction is also defined as a function of the distance r. In this way, the distortion aberration correction information 15 is obtained for the section Q1. In the graph of the distortion aberration correction information 15 for the section Q1 shown in Fig. 2, examples of the coordinate correction rate D _x in the x direction and the coordinate correction rate D _y in the y direction are indicated by thick solid lines and thin solid lines, respectively.

In the same way, the distortion aberration correction information 15 can be obtained also for the other sections Q2 to Q4. The obtained distortion aberration correction information 15 is stored in the memory|storage part 13 (FIG. 1). When the distortion aberration does not depend on the radial direction centering on the reference point O, the coordinate correction rates D _x , D _y become approximately equal in the sections Q1 to Q4. However, in reality, the coordinate correction rates D _x , D _y become non-uniform among sections Q1 to Q4 due to various factors. As a factor of non-uniformity, the inclination of the optical axis of the imaging device 40 with respect to the surface of an observation object, etc. are mentioned, for example.

Next, with reference to FIGS. 3 and 4 , a method of correcting the coordinates of a predetermined location in the image plane 41 (hereinafter, referred to as a location to be corrected) with coordinates at the time of aberration will be described.

3 is a graph for explaining a method of correcting the coordinates in the image plane 41 of the correction target point Pt. 4 is a flowchart showing a procedure for correcting the coordinates in the image plane 41 of the correction target point Pt.

First, a correction target point Pt in the image plane 41 is determined. The correction target point Pt corresponds to the center point of the image of the alignment mark, for example. Based on the position of the correction target point Pt, two sections are selected from the four sections Q1 to Q4 (step S1). For example, from among the boundary lines BL dividing the four divisions Q1 to Q4, the two divisions on both sides of the boundary line BL having the smallest angle between the reference point O and the direction toward the correction target point Pt are selected. In FIG. 3 , the positive portion of the y-axis corresponds to the boundary line BL that satisfies this condition. Two sections Q1 and Q2 on either side of the defining part of the y-axis are selected.

Next, based on the distortion aberration correction information 15 (FIGS. 1 and 2) for the two selected sections Q1 and Q2, the coordinates of the sections Q1 and Q2 corresponding to the distance r from the reference point O to the point to be corrected Pt By weighted averaging the correction rates D _x , D _y , the coordinate correction rates D _xt (r) and D _yt (r) at the position of the correction target point Pt are obtained (step S2). For example, the direction from the reference point O toward the geometric center of the two selected sections Q1 and Q2 (corresponding to the diagonal direction of the sections Q1 and Q2) and the direction from the reference point O toward the correction target point Pt form Based on the angle, a weighted average is performed.

When the angles formed by the direction from the reference point O toward the geometric center of the two selected sections Q1 and Q2 and the direction from the reference point O toward the correction target point Pt are expressed as θ ₁ and θ ₂ , respectively, The coordinate correction rates D _xt (r) and D _yt (r) in the equation are expressed by the following formulas.

[Equation 2]

Here, D _x1 (r) and D _y1 (r) are the coordinate correction rates in the x and y directions obtained for the section Q1, respectively, and D _x2 (r) and D _y2 (r) are, respectively, in the section Q2 It is the coordinate correction rate in the x-direction and the y-direction obtained for

Next, based on the weighted averaged coordinate correction rates D _xt , D _yt of the correction target point Pt, the coordinates in the image plane of the correction target point Pt are corrected (step S3). For example, when the coordinates of the point to be corrected Pt are expressed as (x ₁ , y ₁ ) and the coordinates after correction are expressed as (x ₀ , y ₀ ), the coordinates after correction are calculated using the following formula .

[Equation 3]

Next, the excellent effect of this embodiment will be described with reference to 5A and 5B of FIG. 5 .

5A of FIG. 5 is a diagram showing the distribution of images obtained by capturing a plurality of marks arranged in a matrix form using a telecentric lens. However, in 5A of FIG. 5, the amount of deviation from the mark image to the actual image at the time of aberration is enlarged and shown 100 times. 5A in Fig. 5 shows that the barrel-shaped distortion aberration has occurred.

5B is a diagram showing the coordinates after correction of the image of the mark calculated using the method according to the present embodiment from the coordinates of the actual image of the mark. Also in Fig. 5B, the amount of deviation from the image of the mark at the time of aberration to the image after the coordinate correction is magnified by 100, and is shown. As shown in Fig. 5B, it can be seen that the distortion aberration is corrected and a distribution close to the original matrix arrangement is obtained.

In this way, by using the method according to the above 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 at the time of aberration.

Next, with reference to 6A to 6C in FIG. 6 and 7A to 7D in FIG. 7 , even in a state in which the optical axis of the imaging device 40 ( FIG. 1 ) is inclined with respect to the surface of the measurement object, distortion aberration can be corrected with high precision. A possible reason will be explained.

6A and 6B in FIGS. 6A and 6B, respectively, when the optical axis of the imaging device 40 is perpendicular to the surface of the measurement object, when it is assumed that there is no distortion aberration, and when it is assumed that there is distortion aberration within the image plane 41 It is a diagram showing the image of the mark. The horizontal and vertical axes of 6A and 6B in FIG. 6 indicate positions in the x-direction and the y-direction, respectively. A plurality of marks are arranged at grid points in a grid pattern. In 6A and 6B of Fig. 6, the image of the mark is indicated by a circle symbol painted in black.

When it is assumed that there is no distortion aberration, as shown in Fig. 6A, the positions of the images of the plurality of marks coincide with the grid points of the square grid. When it is assumed that there is distortion aberration, as shown in Fig. 6B, the position of the image of the mark is deviated from the grid point. In Fig. 6B, it is assumed that barrel-type distortion aberration remarkably larger than that of a general lens occurs.

6C of FIG. 6 is a graph plotting the relationship between the coordinate correction rate D _x in the x-direction with respect to the diagonal direction of the image plane and the distance r from the center point of the image plane without distinguishing four diagonal directions. Since the distortion aberration has low dependence on the rotation direction with the center point of the image plane as the rotation center, a plurality of measurement points plotted in four diagonal directions can be approximated with good accuracy by using one approximation curve.

7A and 7B in Figs. 7A and 7B show, respectively, within the image plane 41 in the case where the optical axis of the imaging device 40 is inclined with respect to the surface of the measurement object, when it is assumed that there is no distortion aberration, and when it is assumed that there is distortion aberration. It is a diagram showing the image of the mark. The horizontal and vertical axes of 7A and 7B in FIG. 7 indicate positions in the x-direction and the y-direction, respectively. A plurality of marks are arranged at grid points in a grid pattern. In 7A and 7B of FIG. 7, the image of the mark is indicated by a black circle symbol.

Since the optical axis of the imaging device 40 is tilted, as shown in 7A in Fig. 7, even when it is assumed that there is no distortion aberration, the position of the image of the mark is deviated from the grid point. Since there is no distortion aberration, the image of a straight line on the measurement object becomes a straight line even within the image plane. For example, when the perimeter of the region where the plurality of marks are distributed is square, the perimeter of the region where the images of the marks are distributed in the image plane 41 becomes a trapezoid.

Assuming that the same aberration as the distortion aberration shown in FIG. 6B occurs with respect to the distribution of the mark image shown in 7A in FIG. 7, the area where the image of the mark is distributed in the case of assuming distortion aberration is shown in FIG. As shown in 7B of Fig. 7B, it is shaped like a combination of a trapezoid and a barrel shape.

7C of FIG. 7 shows the coordinate correction rate D _x in the x direction with respect to the diagonal direction of the image plane 41 without discriminating the four diagonal directions of the image plane 41 , and It is a graph plotting the relationship of distance r. Since the magnitude and direction of the distortion aberration are different in the diagonal direction, the plotted measurement points are distributed over a wider range in the vertical axis direction than in the case shown in Fig. 6C. Even if one 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.

7D of FIG. 7 is a graph plotting the relationship between the coordinate correction rate D _x in the x direction with respect to the diagonal direction of the image plane 41 and the distance r from the center point of the image plane by dividing each of the sections Q1 to Q4 am. The square symbol, the triangular symbol, and the circle symbol in the graph are plotted with respect to the measurement points located on the diagonal of the divisions Q2, Q3, and Q4, respectively. In addition, although the coordinate correction rate is computed with respect to the some measurement point also about the division Q1, the measurement point is not shown in 7D of FIG.

The thin dashed line, the thin solid line, the thick dashed line, and the thick solid line in the graph of 7D of FIG. 7 are approximate curves approximating the distribution of the measurement points of the coordinate correction rate in the x-direction for the sections Q1 to Q4, respectively. If attention is paid to one division, the error between the coordinate correction rate obtained from the approximate curve and the coordinate correction rate at a plurality of measurement points is small.

When the optical axis of the imaging device 40 is tilted with respect to the surface of the measurement object, if the coordinates of the correction target point are corrected based on one approximate curve shown in 7C of FIG. , the error between the coordinates after correction and the coordinates at the time of aberration increases. In contrast, in the present embodiment, in step S1 (Fig. 4), from among the four approximation curves shown in Fig. 7D, two approximation curves in which the coordinate correction rate at the correction target location is more accurately reflected are selected. .

Moreover, in step S2 (FIG. 4), the coordinate correction rate calculated|required from two approximation curves is weighted-averaged according to the degree to which the coordinate correction rate in a correction|amendment target location is reflected. For this reason, even when the optical axis of the imaging device 40 is inclined with respect to the surface of the measurement object, the coordinates can be corrected by using a coordinate correction rate close to the actual coordinate correction rate at the location to be corrected. . For this reason, the correction precision of coordinates can be improved.

Next, a modified example of the above embodiment will be described.

In the above embodiment, the image plane 41 (FIG. 2) is divided into four sections Q1 to Q4, but the number of sections is not limited to four. The number of divisions should just be two or more. For example, in the example shown in 7D of FIG. 7, the approximation curves of the division Q1 and the division Q4 approximate each other, and the approximation curve of the division Q2 and the division Q3 approximate each other. Therefore, even if the division Q1 and the division Q4 are integrated into one division, and the division Q2 and the division Q3 are integrated into one division, the correction accuracy of the coordinates can be maintained to a certain degree high.

Further, in the above embodiment, the coordinate correction rate is obtained for a plurality of image points P ₁ (Fig. 2) on each diagonal of the four divisions Q1 to Q4, and one approximate curve is set based on the coordinate correction rate, there is. As a plurality of image points P ₁ serving as a basis for setting the approximation curve, one approximation curve may be set in consideration of the coordinate correction rate at the other image points P ₁ in the division without being limited to the diagonal line.

For example, the coordinate correction rate may be calculated for a plurality of image points P ₁ in a region sandwiched between two radial directions from the reference point O toward the inside of one division. In this case, in order to establish one approximation curve in which the coordinate correction rates at a plurality of image points P ₁ in the division are strongly reflected, the area sandwiched between the two radial directions includes the geometric center of the division in two radial directions. should be set.

Moreover, in the said embodiment, when two divisions are selected in step S1 (FIG. 4), among the four boundary lines BL, the boundary line BL with the smallest angle with the direction from the reference point O toward the correction target point Pt. You are selecting the two compartments on either side of the In addition, you may select two divisions which approximate the coordinate correction rate in the correction target location Pt with high precision.

For example, in the example shown in 7D of FIG. 7, the approximate curve of the division Q1 and the approximate curve of the division Q4 have shown the same tendency with respect to the change of the distance r. This means that when the correction target point Pt is located in the section Q1 or the section Q4, the coordinate correction rate at the correction target point Pt is approximated with high precision in the sections Q1 and Q4. Therefore, when the correction target point Pt is located in the division Q1 or the division Q4, it is good to select the division Q1 and the division Q4 as two divisions in step S1 (FIG. 4). For the same reason, when the correction target point Pt is located in the division Q2 or the division Q3, the division Q2 and the division Q3 may be selected as two divisions in step S1 (FIG. 4).

Moreover, in the said embodiment, although two divisions are selected in step S1 (FIG. 4), you may select one division. For example, when the angle θ ₁ ( FIG. 3 ) is 0° or sufficiently small, only the division Q1 may be selected. What is necessary is just to decide based on the magnitude|size of angle (theta) ₁ whether to select one division or two divisions.

Next, an inkjet drawing apparatus according to another embodiment will be described with reference to FIGS. 8A, 8B, and 9 . The inkjet drawing apparatus according to this embodiment is equipped with the distortion aberration correction apparatus according to the embodiment shown in Figs.

8A of FIG. 8 is a schematic front view of the inkjet drawing apparatus 20. As shown in FIG. A movable table 25 is supported by a moving mechanism 24 on a base 22 . An xyz orthogonal coordinate system is defined in which the x-axis and the y-axis are oriented horizontally and the z-axis is oriented vertically downward. The moving mechanism 24 is controlled by the control device 50 to move the movable table 25 in two directions: the x-direction and the y-direction. As the movement mechanism 24, for example, an XY stage including the X-direction movement mechanism 24X and the Y-direction movement mechanism 24Y can be used.

On the upper surface of the movable table 25, a substrate 80 as a drawing object is supported. The substrate 80 is fixed to the movable table 25 by, for example, a vacuum chuck. Above the movable table 25, the ink discharging unit 30 and the imaging device 40 are supported by, for example, a door-shaped support member 23 .

The imaging device 40 images the upper surface of the substrate 80 . More specifically, a region within the imaging range of the imaging device 40 among the upper surface of the substrate 80 is imaged. The image obtained by the imaging device 40 is input to the distortion aberration correction processing device 10 .

The control device 50 receives position information of the substrate 80 from the distortion aberration correction processing device 10 . By controlling the moving mechanism 24 and the ink discharging unit 30 based on this positional information, the ink is landed at a predetermined position on the surface of the substrate 80 . As a result, a film of ink having a predetermined shape is formed on the surface of the substrate 80 .

8B is a diagram showing the positional relationship of the movable table 25, the ink discharging unit 30, and the imaging device 40 in a plan view. A substrate 80 is supported on the upper surface of the movable table 25 . An ink discharging unit 30 and an imaging device 40 are supported above the substrate 80 . A plurality of nozzles 32 are provided on a surface of the ink discharging unit 30 opposite to the substrate 80 . The control device 50 controls the moving mechanism 24 to move the movable table 25 in the x-direction and the y-direction, and discharges ink from each nozzle 32 of the ink discharging unit 30 . control

Alignment marks 81 are formed at each of the four corners of the substrate 80 . The control device 50 operates the moving mechanism 24 to place each of the alignment marks 81 within the imaging range of the imaging device 40, so that the imaging device 40 can image the alignment marks 81 there is.

9 is a flowchart showing a procedure for performing drawing with an inkjet drawing apparatus. First, the control device 50 operates the moving mechanism 24 to move one alignment mark 81 within the imaging range of the imaging device 40 (step S11). Thereafter, the imaging device 40 images the alignment mark 81 (step S12). The captured image data is input to the distortion aberration correction processing apparatus 10 . The distortion aberration correction processing apparatus 10 detects the coordinates in the image plane of the image of the alignment mark 81 by analyzing the image of the alignment mark 81 (step S13). A known algorithm such as pattern matching can be used to detect the coordinates of the image of the alignment mark 81 .

The distortion aberration correction processing apparatus 10 corrects the coordinates of the image of the alignment mark 81 by executing the procedure according to the embodiment shown in Fig. 4 (step S14). The procedures from step S11 to step S14 are repeated until the coordinates are corrected for all the alignment marks 81 (step S15).

When the correction of the coordinates for all the alignment marks 81 is completed, the distortion aberration correction processing device 10 transmits the corrected coordinates of the image of the alignment marks 81 to the control device 50 (8A and 8B in FIG. 8 ). do (step S16). The control device 50 executes a drawing process based on the corrected coordinates of the image of the alignment mark 81 (step S17).

Next, the excellent effect of this embodiment is demonstrated.

Since the inkjet drawing apparatus according to this embodiment is equipped with the distortion aberration correction processing apparatus 10 shown in Figs. 1 to 4, the position of the alignment mark 81 can be measured with high precision. In particular, even when the optical axis of the imaging device 40 is inclined with respect to the surface of the substrate 80 , a decrease in the measurement accuracy of the position of the alignment mark 81 can be suppressed.

Next, a modified example of the embodiment shown in Figs. 8A to 9 will be described. In the embodiment shown in Figs. 8A to 9, the distortion aberration correction processing apparatus 10 according to the embodiment shown in Figs. 1 to 4 is mounted on the inkjet drawing apparatus, but the embodiment shown in Figs. It is also possible to mount the distortion aberration correction processing apparatus 10 according to the above description in other apparatuses. For example, it can be mounted on a laser processing apparatus for performing punching by applying a laser beam to an object, a laser annealing apparatus for performing annealing by injecting a laser beam on a semiconductor substrate as an object, or the like.

Each of the above-described embodiments is an example, and it cannot be overemphasized that partial substitutions or combinations of configurations shown in other embodiments are possible. The same operation and effect by the same configuration of the plurality of embodiments will not be separately mentioned for each embodiment. In addition, the present invention is not limited to the above-described embodiment. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like are possible.

10 Distortion aberration correction processing device
11 I/O interface part
12 processing unit
13 memory
14 program
15 Distortion Aberration Correction Information
20 Inkjet drawing equipment
22 expectations
23 support member
24 moving mechanism
24X X direction movement mechanism
24Y Y direction movement mechanism
25 movable table
30 Ink discharge unit
32 nozzles
40 imaging device
41 Image plane of the image pickup device
50 control
80 board
81 alignment mark

Claims (5)

Distortion representing the relationship between the coordinate correction rate for correcting the coordinates on the image plane and the distance from the reference point for each of a plurality of divisions divided by a plurality of boundary lines extending radially from the reference point of the image plane of the image pickup device a memory unit storing aberration correction information;
At least one section is selected from the plurality of sections based on the coordinates of the section to be corrected in the image plane, and the distortion aberration correction information for the selected section and the distance from the reference point to the section to be corrected are obtained. A distortion aberration correction processing apparatus comprising a processing unit for determining a coordinate correction rate based on the coordinate correction rate, and correcting the coordinates of the correction target point based on the determined coordinate correction rate. According to claim 1,
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 each of the four sides. 3. The method of claim 1 or 2,
The processing unit, in the processing of correcting the coordinates of the correction target point,
Selecting two divisions on both sides of the boundary line with the smallest angle between the reference point and the direction toward the correction target point among the plurality of boundary lines,
Coordinate correction rate of the distortion aberration correction information for the two selected divisions based on an angle between the reference point from the reference point toward the geometric center of each of the two selected divisions and the direction from the reference point toward the correction target point A distortion aberration correction processing apparatus that weights averages and corrects the coordinates of the correction target point based on the weighted average coordinate correction rate. Distortion aberration correction indicating a relationship between a coordinate correction rate for correcting coordinates in an image and a distance from the reference point for each of a plurality of divisions separated by a plurality of boundary lines extending radially from a reference point in the image plane of the imaging device Using an imaging device for which information is already known, the measurement object is imaged,
Determining a correction target location to correct the coordinates in the image plane,
selecting at least one section from the plurality of sections based on the position of the correction target point in the image plane;
determining a coordinate correction rate based on the distortion aberration correction information for the selected section and the distance from the reference point to the correction target point;
A distortion aberration correction method for correcting the coordinates of the correction target point based on the determined coordinate correction rate. Distortion aberration correction indicating a relationship between a coordinate correction rate for correcting coordinates in an image and a distance from the reference point for each of a plurality of divisions separated by a plurality of boundary lines extending radially from a reference point in the image plane of the imaging device a procedure for acquiring an image of a measurement target imaged using an imaging device for which information is already known;
a procedure for determining a correction target point to be corrected from the image captured by the image pickup device;
a procedure of selecting at least one section from the plurality of sections based on the coordinates in the image plane of the point to be corrected;
a procedure of determining a coordinate correction rate based on the distortion aberration correction information for the selected section and the distance from the reference point to the correction target point;
A computer-readable recording medium recording a program for executing a procedure for correcting the coordinates of the correction target location based on the determined coordinate correction rate.

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