TWI786856B - Distortion aberration correction processing device, distortion aberration correction method and program - Google Patents

Abstract

[Problem] The present invention provides a distortion aberration correction processing device that can perform distortion aberration correction with high accuracy even when the optical axis of an imaging device is inclined with respect to the surface of an object to be measured. [Solution] The memory unit stores distortion aberration correction information for a plurality of segments separated by a plurality of boundary lines extending radially from a reference point on an image plane of the imaging device. Each division area of the area represents the relationship between the coordinate correction rate of the coordinates on the corrected image plane and the distance from the reference point. The processing unit selects at least one compartment area from the plurality of compartment areas according to the coordinates of the correction object in the image plane, and calculates the correction information based on the distortion and aberration correction information of the selected compartment area and the distance between the calibration target part and the reference point. The coordinate correction rate is determined, and the coordinates of the correction target part are corrected according to the determined coordinate correction rate.

Description

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

The invention relates to a distortion aberration correction processing device, a distortion aberration correction method and a program. This application claims priority based on Japanese Patent Application No. 2020-178944 filed on October 26, 2020. The entire content of this Japanese application is incorporated by reference in this specification.

Inkjet devices that draw ink by bouncing ink from an inkjet head onto an object, laser processing devices that impinge a laser beam on an object to perform drilling, and inject a laser beam on a semiconductor as an object In a laser annealing device that performs annealing on a substrate, etc., the alignment mark provided on the object is detected to position the object. At this time, the position of the alignment mark is detected by performing image processing on an image captured with the alignment mark.

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

[Patent Document 1] Japanese Patent Laid-Open No. 2001-133223

[Problem to be solved by the invention]

If the optical axis of the imaging device is inclined with respect to the surface of the object to be measured, the amount of distortion to be corrected varies 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, since the distortion is corrected only by the distance from the origin of the image plane, the distortion cannot be performed with high precision when the optical axis of the imaging device is tilted. Aberration correction.

An object of the present invention is to provide a distortion aberration correction processing device, a distortion aberration correction method, and a program that can perform distortion aberration correction with high precision even when the optical axis of the imaging device is inclined relative to the surface of the object to be measured. . [Technical means to solve the problem]

According to an aspect of the present invention, a distortion and aberration correction processing device is provided, which has: a memory unit storing distortion aberration correction information for each of a plurality of partitions divided by a plurality of boundary lines extending radially from a reference point on an image plane of the imaging device a segment area, indicating the relationship between the coordinate correction rate for correcting the coordinates on the aforementioned image plane and the distance from the aforementioned reference point; and The processing unit selects at least one segmental area from the plurality of segmental areas according to the coordinates of the correction target part in the aforementioned image plane, and based on the aforementioned distortion aberration correction information for the selected segmental area and the aforementioned correction target part The coordinate correction rate is determined by the distance from the reference point, and the coordinates of the calibration target part are corrected according to the determined coordinate correction rate.

According to another aspect of the present invention, a distortion aberration correction method is provided, wherein, The object to be measured is photographed using an image pickup device having known distortion aberration correction information for a plurality of borderlines separated by a plurality of boundary lines extending radially from a reference point in an image plane of the image pickup device Each segment area of the segment area represents the relationship between the coordinate correction rate of the coordinates in the corrected image and the distance from the aforementioned reference point, Determine the correction target part for correction of the coordinates in the aforementioned image plane, selecting at least one compartmental area from the plurality of compartmental areas according to the position of the correction target part in the aforementioned image plane, The coordinate correction rate is determined according to the aforementioned distortion and aberration correction information for the selected partition area and the distance between the aforementioned correction target part and the aforementioned reference point, Correct the coordinates of the aforementioned calibration target parts according to the determined coordinate calibration rate.

According to another viewpoint of the present invention, a program is provided, which causes the computer to perform the following steps: A step of acquiring an image of a measurement object captured by a known imaging device using distortion aberration correction information for complex numbers extending radially from a reference point in an image plane of the imaging device Each of the plurality of compartments divided by a boundary line represents the relationship between the coordinate correction rate of the coordinates in the corrected image and the distance from the aforementioned reference point; Steps of determining the correction target part to be corrected from the image captured by the above-mentioned camera device; A step of selecting at least one segmented area from the plurality of segmented areas according to the coordinates of the aforementioned calibration target part in the aforementioned image plane; The step of determining the coordinate correction rate according to the aforementioned distortion and aberration correction information for the selected compartment area and the distance between the aforementioned correction target part and the aforementioned reference point; and A step of correcting the coordinates of the aforementioned correction target part according to the determined coordinate correction rate. [Effect of Invention]

Divide the image plane into a plurality of compartments, and use the distortion aberration correction information set for each compartment to correct the distortion even if the optical axis of the imaging device is inclined relative to the surface of the measurement object Distortion aberrations can be corrected with high precision even in this state.

Referring to FIG. 1 to FIG. 9, a distortion aberration correction processing device based on an embodiment will be described. FIG. 1 is a block diagram of a distortion aberration correction processing device 10 based on an embodiment. The distortion aberration correction processing device 10 based on this embodiment includes an input/output interface unit 11 , a processing unit 12 and a memory unit 13 . For the processing unit 12, for example, a computer can be used. The program 14 executed by the computer is stored in the memory unit 13 . Distortion aberration correction information 15 is also stored in the memory unit 13 . The contents of the distortion correction information 15 will be described later with reference to FIG. 2 . As the memory unit 13 , for example, an auxiliary memory device such as a hard disk drive (HDD) or a solid state disk (SSD) can be 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 the image are offset from the actual coordinates representing the positions of the actual alignment marks due to the distortion of the lens. The processing unit 12 uses the distortion and aberration correction information 15 stored in the memory unit 13 to correct the coordinates of the image, so as to reduce the error with the actual coordinates of the alignment marks. Afterwards, the corrected coordinates are transmitted to the control device 50 through the input/output interface portion 11 . The control device 50 performs various processes according to the corrected coordinates of the alignment marks. The processing unit 12 and the control device 50 can be realized using a shared computer. At this time, the processing unit 12 transmits the corrected coordinates of the alignment mark to the control device 50 without going through the input/output interface unit 11 .

FIG. 2 is a diagram showing the contents of the distortion correction information 15 . An xy Cartesian coordinate system with the reference point O as the origin is defined on the image plane 41 of the imaging device 40 ( FIG. 1 ). Object points within the image field of the camera 40 are transferred onto 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 y-axis are defined to be parallel to any side on the image plane 41 .

The image plane 41 is divided into a plurality of partition areas Q1 - Q4 by a plurality of boundary lines BL extending radially from the reference point O. In the case of this embodiment, a line segment connecting the reference point O and the midpoint of each side of the image plane 41 is used as the boundary line 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 compartments Q1 to Q4 correspond to the first to fourth quadrants of the xy coordinate system, respectively.

Due to the influence of distortion aberration of the lens, etc., the position of the image point P ₁ corresponding to a certain observation point is shifted from the position of the image point P ₀ when the lens is assumed to have no aberration. The distortion and aberration correction information 15 is used to correct the coordinates _of the image point P1 to obtain the coordinate information of the image point P0 when there is no aberration, and includes the coordinate correction rate D in the _x direction and the coordinate correction rate D in the _y direction _y .

Next, a method of obtaining the distortion correction information 15 of the segmented area Q1 will be described. An image of an observation target object on which a plurality of marks having known positions are formed is captured using an imaging device 40 ( FIG. 1 ). The plurality of marks are, for example, checkered dots. 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 captured image of the marker to detect the position of the marker image, and moving the object to be observed based on the detection result, the marker image serving as the reference point can be made to coincide with the reference point O of the image plane 41 . This step can be repeated multiple times in order to increase the accuracy of both coincidences.

By analyzing the obtained image, a plurality of image points located on the diagonal line of the partition area Q1 with the reference point O as one end are extracted from the plurality of marked image points. One pixel among the plurality of extracted pixels is expressed as P ₁ . The aberration-free image point corresponding to the image point P ₁ is expressed as P ₀ . _The coordinates of the image point P1 are determined by image analysis. The coordinates of the image point P ₀ corresponding to the image point P ₁ when there is no aberration 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.

The coordinate correction rate D _x in the x direction is the displacement amount x ₁ -x ₀ in the x direction from the image point P ₀ to the actual image point P ₁ when there is no aberration and the image from the reference point O to the image when there is no aberration The ratio of the length x ₀ in the x direction up to the point P ₀ . The coordinate correction rate D _y in the y direction is the displacement amount y ₁ -y ₀ in the y direction from the image point P ₀ when there is no aberration to the actual image point P ₁ and the image from the reference point O to the image when there is no aberration The ratio of the length y ₀ in the y direction up to the point P ₀ . Generally, the distortion aberration of the lens is small at the center of the image plane and large at the peripheral portion. Therefore, the coordinate correction rates D _x , D _y depend on the distance r from the reference point O.

On _a graph whose horizontal axis is the distance r from the reference point O to the actual image point P1 and whose vertical axis is the coordinate correction rate Dx in the _x direction, a plurality of image points P1 _on the diagonal are plotted measurement results. Determines the approximation curve that approximates the distribution of the plotted complex number of points. Thereby, as shown in FIG. 2 , the coordinate correction rate D _x in the x direction for the compartment Q1 is defined as a function of the distance r. Similarly, the coordinate correction rate D _y in the y direction is also defined as a function of the distance r. Thereby, the distortion aberration correction information 15 is calculated|required about the compartment area Q1. In the graph of the distortion aberration correction information 15 for the segment area Q1 shown in FIG. 2, the coordinate correction rate D _x in the x direction and the coordinate correction rate D _y in the y direction are represented by a thick solid line and a thin solid line, respectively. an example.

The distortion and aberration correction information 15 can also be obtained for the other compartments Q2 - Q4 in the same way. The calculated distortion and aberration correction information 15 is stored in the memory unit 13 (FIG. 1). In the case that the distortion aberration does not depend on the radiation direction centered on the reference point O, the coordinate correction ratios D _x and D _y are approximately the same among the partition areas Q1-Q4. However, in reality, the coordinate correction rates D _x , D _y vary among the compartments Q1 to Q4 due to various reasons. As a cause of the deviation, for example, the optical axis of the imaging device 40 is inclined with respect to the surface of the object to be observed.

Next, a method of correcting the coordinates of a certain part (hereinafter referred to as a correction target part) in the image plane 41 to coordinates without aberration will be described with reference to FIGS. 3 and 4 . FIG. 3 is a graph for explaining a method of correcting the coordinates of the correction target part Pt within the image plane 41 . FIG. 4 is a flow chart showing the steps of correcting the coordinates of the correction target part Pt in the image plane 41 .

First, the correction target part Pt in the image plane 41 is determined. The correction target site Pt corresponds to, for example, the center point of the image of the alignment mark. Two compartments are selected from the four compartments Q1 to Q4 according to the position of the correction target part Pt (step S1 ). For example, among the boundary lines BL dividing the four compartmental areas Q1-Q4, two compartmental areas on both sides of the borderline BL with the smallest angle formed with the direction from the reference point O toward the correction target part Pt are selected. In FIG. 3, the positive part of the y-axis corresponds to the boundary line BL satisfying this condition. Two compartments Q1 and Q2 on both sides of the positive portion of the y-axis are selected.

Next, based on the distortion correction information 15 (FIGS. 1 and 2) for the two selected compartments Q1 and Q2, the compartment Q1 corresponding to the distance r from the reference point O to the correction target part Pt is corrected. The coordinate correction rates _Dx , _Dyt (r) of the correction target part Pt are obtained by weighted average of the coordinate correction rates _Dx , _Dyt (r) of the correction target part Pt (step S2). For example, according to the direction from the reference point O to the geometric centers of the two selected compartments Q1, Q2 (corresponding to the diagonal direction of the compartments Q1, Q2) and the direction from the reference point O to the calibration target part Pt The angle formed is weighted average.

其中，D _x1(r)、D _y1(r)分別為針對區隔區Q1所求出之x方向及y方向的座標校正率，D _x2(r)、D _y2(r)分別為針對區隔區Q2所求出之x方向及y方向的座標校正率。 When the angles formed by the direction from the reference point O toward the geometric centers of the two selected compartments Q1 and Q2 and the direction from the reference point O toward the calibration target part Pt are respectively expressed as θ ₁ and θ ₂ , the calibration The coordinate correction ratios D _xt (r) and _Dyt (r) on the target site Pt are represented by the following equations.

Among them, D _x1 (r) and D _y1 (r) are the coordinate correction rates in the x direction and y direction calculated for the compartment Q1 respectively, and D _x2 (r) and _Dy2 (r) are the coordinate correction rates for the compartment Q1 respectively. The coordinate correction rate in the x-direction and y-direction calculated in the area Q2.

Next, the coordinates of the correction target part Pt in the image plane are corrected according to the weighted average coordinate correction rates _Dxt and _Dyt on the correction target part Pt (step S3). For example, when the coordinates of the correction target site Pt are expressed as (x ₁ , y ₁ ) and the corrected coordinates are expressed as (x ₀ , y ₀ ), the corrected coordinates are calculated using the following equation.

Next, the excellent effects of this embodiment will be described with reference to FIG. 5A and FIG. 5B . FIG. 5A is a diagram showing an image distribution obtained by photographing a plurality of marks arranged in a matrix using a telecentric lens. In addition, in FIG. 5A , the amount of shift from the image of the marker in the absence of aberration to the actual image is shown enlarged by 100 times. In FIG. 5A , it can be seen that barrel-type distortion aberration occurs.

FIG. 5B is a diagram showing the corrected coordinates of the marker image calculated using the method of this embodiment from the coordinates of the actual marker image. Also in FIG. 5B , the amount of shift from the image of the marker in the absence of aberration to the image after coordinate correction is enlarged by 100 times and shown. As shown in FIG. 5B , it can be seen that the distortion aberration is corrected to obtain a distribution close to the original matrix-like arrangement.

In this way, by using the method based on 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.

Next, the reason why the distortion aberration can be corrected with high precision even when the optical axis of the imaging device 40 (FIG. 1) is inclined relative to the surface of the object to be measured will be discussed with reference to FIGS. 6A to 6C and FIGS. 7A to 7D. illustrate.

6A and 6B respectively show images of marks in the image plane 41 when the optical axis of the imaging device 40 is perpendicular to the surface of the object to be measured assuming that there is no distortion aberration and when there is distortion aberration. map. The abscissa and ordinate of FIGS. 6A and 6B represent positions in the x-direction and y-direction, respectively. A plurality of marks are arranged on grid points of the checkered pattern. In FIGS. 6A and 6B , the images of the marks are represented by circular marks painted in black.

Assuming 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. Under the assumption of distortion aberration, the position of the marked image is shifted from the grid point as shown in FIG. 6B. In FIG. 6B , it is assumed that a barrel-type distortion aberration significantly larger than that of an ordinary lens is generated.

6C is a graph plotting the relationship between the coordinate correction rate D _x in the x direction of 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. 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 for four diagonal directions can be accurately approximated on one approximate curve.

7A and 7B show images of marks in the image plane 41 when the optical axis of the imaging device 40 is inclined relative to the surface of the object to be measured assuming that there is no distortion aberration and when there is distortion aberration, respectively. map. The abscissa and ordinate of FIGS. 7A and 7B represent positions in the x-direction and y-direction, respectively. A plurality of marks are arranged on grid points of the checkered pattern. In FIGS. 7A and 7B , the images of the marks are represented by circular marks painted in black.

Since the optical axis of the imaging device 40 is inclined, as shown in FIG. 7A , even assuming no distortion aberration, the position of the image of the mark is shifted from the grid point. Since there is no distortion, the image of a straight line on the measurement object becomes a straight line even in the image plane. For example, when the outer circumference of the area where a plurality of marks are distributed is a square, the outer circumference of the area where the images of the marks are distributed in the image plane 41 is a trapezoid.

If it is assumed that the same aberration as the distortion aberration shown in FIG. 6B occurs with respect to the image distribution of the mark shown in FIG. 7A, then as shown in FIG. The area becomes a shape such as a combination of a trapezoid and a barrel.

FIG. 7C plots the coordinate correction rate D _x in the x direction of the diagonal direction of the image plane 41 and the distance r from the center point of the image plane 41 without distinguishing the four diagonal directions of the image plane 41. diagram of the relationship. The magnitude or orientation of the distortion aberration differs between diagonal directions, so compared with the case shown in FIG. 6C , the plotted measurement points are distributed over a wide range in the vertical axis direction. 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.

FIG. 7D is a diagram of the relationship between the coordinate correction rate D _x in the x direction of the diagonal direction of the image plane 41 and the distance r from the center point of the image plane by differentiating each of the partition areas Q1-Q4. The square marks, triangle marks, and circle marks in the graph draw the measurement points located on the diagonal lines of the partition areas Q2, Q3, and Q4, respectively. Furthermore, the coordinate correction rate is also calculated for a plurality of measurement points in the compartment Q1 , but the measurement points are not shown in FIG. 7D .

The thin dotted line, thin solid line, thick dotted line, and thick solid line in the graph of FIG. 7D are approximate curves that approximate the distribution of measurement points for the coordinate correction rate in the x direction of the compartments Q1 to Q4 . If we focus on one compartment, 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 inclined relative to the surface of the object to be measured, if the coordinates of the correction target part are corrected according to an approximate curve shown in FIG. 7C , the corrected coordinates will be the same as those without aberration The error of the coordinates becomes large depending on the position of the correction target part. On the other hand, in this embodiment, in step S1 ( FIG. 4 ), among the four approximate curves shown in FIG. 7D , two approximate curves that more accurately reflect the coordinate correction rate on the correction target site are selected.

Furthermore, in step S2 (FIG. 4), the coordinate correction ratios obtained from the two approximate curves are weighted and averaged according to the extent to which the coordinate correction ratios on the correction target site are reflected. Therefore, even when the optical axis of the imaging device 40 is inclined with respect to the surface of the object to be measured, the coordinates can be corrected using a coordinate correction rate close to the actual coordinate correction rate on the correction target site. Therefore, the correction accuracy of the coordinates can be improved.

Next, modifications of the above-described embodiment will be described. In the above embodiment, the image plane 41 ( FIG. 2 ) is divided into four partitions Q1 - Q4 , but the number of partitions is not limited to four. The number of compartments may be two or more. For example, in the example shown in FIG. 7D , the approximate curves of the partitioned region Q1 and the partitioned region Q4 are similar to each other, and the approximate curves of the partitioned region Q2 and Q3 are similar to each other. Therefore, even if the compartment Q1 and the compartment Q4 are combined into one compartment and the compartment Q2 and the compartment Q3 are combined into one compartment, high coordinate correction can be maintained to a certain extent. precision.

Also, in the above-mentioned embodiment, the coordinate correction rate is obtained for the plurality of image points P1 (FIG. ₂ ) on the diagonal line of each of the four compartmental areas Q1~Q4, and an approximation is set based on the coordinate correction rate. curve. The plurality of pixel points P ₁ used as the basis for setting the approximate curve is not limited to the diagonal line, and one approximate curve can be set in consideration of the coordinate correction ratios of other pixel points P ₁ in the segmented area.

For example, the coordinate correction rate can be obtained for a plurality of image points P ₁ in an area sandwiched by two radiation directions from the reference point O to one compartment. At this time, in order to set an approximate curve that strongly reflects the coordinate correction rate in the plurality of image points P1 in the compartment, set ₂ in such a way that the area sandwiched by the two radiation directions includes the geometric center of the compartment. a radiation direction.

Also, in the above-mentioned embodiment, when two compartments are selected in step S1 (FIG. 4), the boundary with the smallest angle formed with the direction from the reference point O toward the correction target part Pt among the four boundary lines BL is selected. 2 partitions on either side of the line BL. In addition, it is possible to select two divisional areas that approximate the coordinate correction rate on the correction target portion Pt with high accuracy.

For example, in the example shown in FIG. 7D , the approximate curve of the compartmentalized region Q1 and the approximated curve of the compartmentalized region Q4 show the same tendency with respect to the change of the distance r. This means that when the correction target part Pt is located in the compartment Q1 or the compartment Q4, the coordinate correction rate on the correction target part Pt is approximated with high precision in the compartment Q1 and the compartment Q4. Therefore, when the correction target part Pt is located in the segmented area Q1 or the segmented area Q4, in step S1 (FIG. 4), the segmented area Q1 and the segmented area Q4 may be selected as two segmented areas. Considering the same reason, when the correction target part Pt is located in the compartment Q2 or the compartment Q3, in step S1 (FIG. 4), the compartment Q2 and the compartment Q3 are selected as two compartments. That's it.

Also, in the above-mentioned embodiment, two compartments are selected in step S1 (FIG. 4), but one compartment may be selected. For example, in the case where the angle θ ₁ ( FIG. 3 ) is 0° or sufficiently small, only the compartmental region Q1 can be selected. Depending on the size of the angle θ ₁ , it is sufficient to select one compartment or two compartments.

Next, an inkjet drawing device based on other embodiments will be described with reference to FIGS. 8A , 8B and 9 . The inkjet drawing device based on this embodiment is equipped with the distortion aberration correction device based on the embodiment shown in FIGS. 1 to 4 .

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

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

The imaging device 40 images the upper surface of the substrate 80 . More specifically, a region within the image field of the imaging device 40 on the upper surface of the substrate 80 is captured. 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 correction processing device 10 . The moving mechanism 24 and the ink discharge unit 30 are controlled according to the position information, so that the ink is bounced to a predetermined position on the surface of the substrate 80 . Thereby, a film of ink of a predetermined shape is formed on the surface of the substrate 80 .

FIG. 8B is a diagram showing the positional relationship among the movable stage 25, the ink discharge 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 discharge 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 discharge 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 also controls discharge of ink from each nozzle 32 of the ink discharge unit 30 .

Alignment marks 81 are respectively formed on the four corners of the substrate 80 . The control device 50 can image the alignment marks 81 by the imaging device 40 by operating the moving mechanism 24 so as to arrange each of the alignment marks 81 within the image field of the imaging device 40 .

Fig. 9 is a flow chart showing the steps of drawing using the inkjet drawing device. First, the control device 50 operates the moving mechanism 24 to move one alignment mark 81 within the image field of the imaging device 40 (step S11 ). After that, the imaging device 40 images the alignment mark 81 (step S12). The captured image data is input to the distortion and aberration correction processing device 10 . The distortion correction processing device 10 detects the coordinates of the image of the alignment mark 81 in the image plane 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 device 10 corrects the coordinates of the image of the alignment mark 81 by performing the steps based on the embodiment shown in FIG. 4 (step S14 ). The steps from step S11 to step S14 are repeated until the coordinates of all alignment marks 81 are corrected (step S15 ).

When the correction of the coordinates of all the alignment marks 81 is completed, the distortion correction processing device 10 transmits the corrected coordinates of the images of the alignment marks 81 to the control device 50 ( FIGS. 8A and 8B ) (step S16 ). The control device 50 performs drawing processing according to the corrected coordinates of the image of the alignment mark 81 (step S17 ).

Next, the excellent effect of this embodiment will be described. Since the inkjet drawing device according to this embodiment is equipped with the distortion correction processing device 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 , it is possible to suppress a decrease in the measurement accuracy of the position of the alignment mark 81 .

Next, modifications 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 device 10 based on the embodiment shown in FIGS. 1 to 4 is mounted on the inkjet drawing device, but based on the The distortion aberration correction processing device 10 of the embodiment can also be mounted on other devices. For example, it can also be mounted on a laser processing device that makes a laser beam incident on an object to perform drilling, a laser annealing device that makes a laser beam incident on a semiconductor substrate as an object and performs annealing, and the like.

The above-described embodiments are examples, and it goes without saying that partial substitution or combination of structures shown in different embodiments is possible. Regarding the same function and effect based on the same structure of multiple embodiments, it is not mentioned one by one in each embodiment. Furthermore, the present invention is not limited to the above-described embodiments. For example, it is obvious to those skilled in the art that various changes, improvements, combinations, etc. can be made.

10: Distortion aberration correction processing device 11: Input/output interface section 12: Processing Department 13: Memory Department 14: Program 15: Distortion and aberration correction information 20: Inkjet drawing device 22: base 23: Support member 24: Mobile Mechanism 24X: X direction moving mechanism 24Y: Y direction moving mechanism 25: Movable carrier 30: ink spit unit 32: Nozzle 40: camera device 41: Image plane of camera device 50: Control device 80: Substrate 81:Alignment mark

[ Fig. 1 ] is a block diagram of a distortion aberration correction processing device based on an embodiment. [ Fig. 2 ] is a diagram showing contents of distortion aberration correction information. [FIG. 3] It is a graph for explaining the method of correcting the coordinates of the correction target part in an image plane. [FIG. 4] It is a flowchart which shows the procedure of correcting the coordinate of the correction target part in an image plane. [FIG. 5A] is a diagram showing the distribution of images obtained by photographing a plurality of marks arranged in a matrix using a telecentric lens, and [FIG. 5B] shows the coordinates of the images based on the marks calculated using the method based on this embodiment. Map of the corrected coordinates of the markers. [FIG. 6A and FIG. 6B] are images showing marks 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 when there is distortion aberration, respectively. The figure, [FIG. 6C] is a graph plotting the relationship between the coordinate correction rate D _x in the x direction of the diagonal direction of the image plane and the distance r from the center point of the image plane. [FIG. 7A and FIG. 7B] are diagrams showing marks in the image plane when there is no distortion aberration and when there is distortion aberration under the condition that the optical axis of the imaging device can be inclined relative to the surface of the object to be measured. The graph of the image, [Fig. 7C] is to plot the coordinate correction rate D _x in the x direction of the diagonal direction of the image plane and the distance from the center point of the image plane without distinguishing the 4 diagonal directions of the image plane The graph of the relationship between the distance r, [Figure 7D] is to distinguish the partition areas Q1~Q4 and plot the coordinate correction rate D _x in the x direction for the diagonal direction of the image plane and the distance from the center point of the image plane A graph of the relationship of r. [FIG. 8A] is a schematic front view of an inkjet drawing device according to another embodiment, and [FIG. 8B] is a diagram showing a positional relationship among a movable stage, an ink discharge unit, and an imaging device when viewed from above. [ Fig. 9 ] is a flow chart showing the steps of drawing using the inkjet drawing device.

41: Image plane

BL: Borderline

D _x : Coordinate correction rate

D _y : Coordinate correction rate

O: reference point

P ₀ : pixel

P ₁ : pixel

Q1: Partition area

Q2: Partition area

Q3: Partition area

Q4: Partition area

r: distance

Claims (5)

A distortion aberration correction processing device comprising: a memory unit storing distortion aberration correction information for a plurality of points extending radially from a reference point on an image plane of an imaging device Each of the plurality of compartments divided by the boundary line represents the relationship between the coordinate correction rate of correcting the coordinates on the aforementioned image plane and the distance from the aforementioned reference point; Coordinates in the image plane Select at least one segmental area from the plurality of segmental areas, and determine the coordinate correction based on the aforementioned distortion and aberration correction information for the selected segmental area and the distance between the aforementioned correction target part and the aforementioned reference point rate, and correct the coordinates of the aforementioned correction target part according to the determined coordinate correction rate. The coordinates of the above-mentioned correction target part are corrected by information of two partition areas on both sides of the boundary line where the angle formed by the direction of the target part is the smallest. The distortion and aberration correction processing device according to claim 1, wherein the shape of the aforementioned image plane is square or rectangular, the aforementioned reference point is located at the center of the aforementioned image plane, and the aforementioned plurality of boundary lines connect the center of the aforementioned image plane 4 line segments between the midpoints of each of the 4 sides. Distortion aberration correction as described in claim 1 or claim 2 The processing device, wherein the processing section corrects the coordinates of the calibration target part according to the direction from the reference point toward the geometric center of each of the two selected partitions and the direction from the reference point The angle formed by the direction towards the aforementioned calibration target part is weighted average of the coordinate correction rate of the aforementioned distortion aberration correction information of the two selected compartments, and the aforementioned calibration target is corrected according to the coordinate correction rate after the weighted average The coordinates of the part. A distortion aberration correction method in which an object to be measured is photographed using an image pickup device having known distortion aberration correction information for a point extending radially from a reference point in an image plane of the image pickup device Each of the plurality of compartments divided by the plurality of boundary lines indicates the relationship between the coordinate correction rate of the coordinates in the corrected image and the distance from the aforementioned reference point, and determines the correction of the coordinates in the aforementioned image plane For the correction target part, at least one compartment is selected from the plurality of compartments according to the position of the correction target part in the aforementioned image plane, and based on the aforementioned distortion and aberration correction information for the selected compartment and the aforementioned The coordinate correction rate is determined by the distance between the correction target part and the aforementioned reference point, and the coordinates of the aforementioned correction target part are corrected according to the determined coordinate correction rate; In the process of correcting the coordinates of the correction target part, the two compartments on both sides of the boundary line forming the smallest angle with the direction from the reference point toward the correction target part among the plurality of boundary lines are used. information to correct the coordinates of the aforementioned correction target parts. A distortion aberration correction program, which causes a computer to execute the following steps: a step of acquiring an image of a measuring object captured by a known imaging device using distortion aberration correction information for the image taken by the camera The reference point in the image plane of the device is divided by a plurality of boundary lines that extend radially. Each of the plurality of partitions indicates the coordinate correction rate of the coordinates in the corrected image and the distance from the aforementioned reference point. relationship; the step of determining the correction target part to be corrected from the image captured by the aforementioned imaging device; selecting at least one segment from the aforementioned plurality of segment areas according to the coordinates of the aforementioned correction target part in the aforementioned image plane The step of the area; the step of determining the coordinate correction rate according to the aforementioned distortion aberration correction information for the selected segment area and the distance between the aforementioned correction target part and the aforementioned reference point; and correcting the aforementioned correction based on the determined coordinate correction rate The step of the coordinates of the target part; in the process of correcting the coordinates of the aforementioned correction target part, use the two sides of the boundary line which forms the smallest angle with the direction from the aforementioned reference point toward the aforementioned correction target part among the plurality of boundary lines The information of the 2 compartments is used to calibrate the coordinates of the above-mentioned correction target part.

Images