Calculation device and calculation method

Abstract

Provided is a computing device which, when one of a substrate and a mask has four marks arranged to be positioned at the apexes of a rectangle, wherein a line connecting a first mark and a second mark among the four marks and a line connecting a third mark and a fourth mark among the four marks are orthogonal to each other, the other of the substrate and the mask having a fifth mark, uses imaging data of the substrate and the mask superimposed upon each other in which the five marks are exposed and the fifth mark is positioned at the center of the four marks to compute an inclination of an image based on the imaging data on the basis of the first mark and the second mark or the third mark and the fourth mark, and computes the amount of positional deviation between the center of the four marks and the fifth mark on the basis of a distance per unit pixel in a direction in which the first mark and the second mark are arranged side by side and a distance per unit pixel in a direction in which the third mark and the fourth mark are arranged side by side.

Description

[Technical field]

[0001] The present invention relates to an arithmetic device and a arithmetic method for calculating the positional misalignment between a substrate and a mask. [Background technology]

[0002] In a printing machine that prints solder paste or the like on a substrate, the substrate and a mask are aligned, as described in the following patents. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-018122 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to accurately align a substrate and a mask. [Means for solving the problem]

[0005] In order to solve the above problem, this specification provides a method for manufacturing a substrate having a substrate and a mask on which four marks are formed, the four marks being arranged at the vertices of a rectangle, a line connecting a first mark and a second mark of the four marks being perpendicular to a line connecting a third mark and a fourth mark of the four marks, and a fifth mark being formed on the other of the substrate and the mask, the five marks being exposed, and imaging data of the substrate and the mask being superimposed such that the fifth mark is located at the center of the four marks is used to calculate the tilt of an image based on the imaging data, based on the first mark and the second mark or the third mark and the fourth mark, and based on the distance per unit pixel in the direction in which the first mark and the second mark are aligned and the distance per unit pixel in the direction in which the third mark and the fourth mark are aligned, After correcting the difference in the number of pixels caused by the misalignment of the optical axis of the camera that captured the image,A calculation device is disclosed that calculates the amount of positional deviation between the center of the four marks and the fifth mark.

[0006] Furthermore, in order to solve the above-mentioned problems, the present specification provides a method for detecting a tilt of an image based on imaging data of a substrate and a mask, in which four marks arranged to be located at the vertices of a rectangle are recorded on one of the substrate and the mask, a line connecting a first mark and a second mark of the four marks is perpendicular to a line connecting a third mark and a fourth mark of the four marks, and a fifth mark is recorded on the other of the substrate and the mask, the five marks are exposed, and the substrate and the mask are overlapped so that the fifth mark is located at the center of the four marks, and the method uses imaging data of the substrate and the mask that are overlapped so that the fifth mark is located at the center of the four marks to calculate a tilt of an image based on the imaging data based on the first mark and the second mark or the third mark and the fourth mark, and calculates a tilt of an image based on the imaging data based on the distance per unit pixel in the direction in which the first mark and the second mark are aligned and the distance per unit pixel in the direction in which the third mark and the fourth mark are aligned, After correcting the difference in the number of pixels caused by the misalignment of the optical axis of the camera that captured the image, A calculation method for calculating the amount of positional deviation between the center of the four marks and the fifth mark is disclosed. Effect of the Invention

[0007] In the present disclosure, four marks arranged to be located at the vertices of a rectangle are written on one of the substrate and the mask, a line connecting the first mark and the second mark of the four marks is perpendicular to a line connecting the third mark and the fourth mark of the four marks, and a fifth mark is written on the other of the substrate and the mask. Then, based on the imaging data of the substrate and the mask overlapped so that the fifth mark is located at the center of the four marks, the tilt of the image based on the imaging data and the positional deviation amount between the center of the four marks and the fifth mark are calculated. This allows the substrate and the mask to be accurately aligned. [Brief description of the drawings]

[0008] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a block diagram showing a control device. [Figure 4] FIG. 13 is a diagram showing a state in which a jig substrate on which a vernier-shaped pattern is formed and a jig mask on which a vernier-shaped pattern is formed are aligned with each other. [Diagram 5] FIG. 13 is a diagram showing a state in which a jig substrate on which a vernier-shaped pattern is formed and a jig mask on which a vernier-shaped pattern is formed are aligned with each other. [Figure 6] FIG. [Figure 7] FIG. 13 is a diagram showing a reference pattern. [Figure 8] FIG. [Figure 9] 13A and 13B are diagrams showing a reference pattern and a measurement pattern on a jig substrate and a jig mask in an aligned state. [Figure 10] FIG. 13 is a diagram showing a reference pattern of a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as modes for carrying out the present invention.

[0010] A printer 10 is shown in Figures 1 and 2. The printer 10 is a work machine for printing solder paste on a circuit board. The printer 10 includes a conveying device 20, a mask holding device 22, an imaging device 23, a squeegee device 24, a solder supplying device 26, and a control device (see Figure 3) 28. Note that Figure 1 is a diagram showing the printer 10 from a side perspective, and Figure 2 is a diagram showing the printer 10 from an above perspective.

[0011] The transport device 20 includes a conveyor device 30 and a board lifting device 32. The conveyor device 30 includes a pair of conveyor belts 34 and an electromagnetic motor (see FIG. 3) 36 that rotates the conveyor belts 34. The direction in which the conveyor belts 34 extend is called the X direction, the direction horizontally perpendicular to the X direction is called the Y direction, and the direction perpendicular to both the X direction and the Y direction is called the Z direction. A circuit board 38 is supported by the pair of conveyor belts 34, and is transported in the X direction by driving the electromagnetic motor 36. The board lifting device 32 is disposed between the pair of conveyor belts 34, and supports the circuit board 38 supported by the pair of conveyor belts 34 from the bottom surface of the circuit board 38 via support pins 40, and lifts and lowers the circuit board 38 at a predetermined position.

[0012] The mask holding device 22 is for holding the mask 50 in a fixed manner, and the mask 50 is made of a metal, for example, a stainless steel sheet, and has a plurality of through holes (not shown). The mask holding device 22 has a mask support table 52 arranged above the transport device 20, and a mask holding mechanism 54 arranged on the upper surface of the mask support table 52. An opening (not shown) is formed in the center of the mask support table 52, and the mask 50 is placed on the mask support table 52 so as to cover the opening. The mask 50 placed on the mask support table 52 is held in a fixed manner by the mask holding mechanism 54. The mask holding mechanism 54 has an adjustment device 56 for adjusting the position of the held mask 50 in the X and Y directions, and for adjusting the rotation angle around a vertical line with the center of the mask as the axis.

[0013] The opening formed in the mask support stand 52 is larger than the circuit board 38. The circuit board 38, which has been transported to a predetermined position by the transport device 20, is raised by the substrate lifting device 32 so that it comes into close contact with the lower surface of the mask 50 held by the mask holding device 22. The circuit board 38, which is in close contact with the lower surface of the mask 50, is lowered by the substrate lifting device 32 so that it moves away from the lower surface of the mask 50.

[0014] The imaging device 23 also has a camera moving device 60, an upper camera 62, and a lower camera 64. The camera moving device 60 includes a pair of slide rails 66, a Y slider 68, and an X slider 70. The pair of slide rails 66 are disposed between the transport device 20 and the mask holding device 22 in the vertical direction so as to extend parallel to each other and in the Y direction. The Y slider 68 is slidably held by the pair of slide rails 66, and slides in the Y direction by the operation of an electromagnetic motor (see FIG. 3) 72. The X slider 70 is attached to the lower surface side of the Y slider 68 so as to be slidable in the X direction, and slides in the X direction by the operation of an electromagnetic motor (see FIG. 3) 76. Slide rail 66 does not overlap with board lifting device 32 of transport device 20 in the vertical direction, and as Y slider 68 moves from above board lifting device 32, circuit board 38 is lifted by board lifting device 32 without coming into contact with imaging device 23. X slider 70 extends laterally from the underside of Y slider 68, and upper camera 62 is attached to the upper surface of the extended X slider 70 facing upward. Meanwhile, lower camera 64 is attached to the underside of X slider 70 facing downward.

[0015] The squeegee device 24 also includes a squeegee moving device 80, a pair of squeegees 82, 84, and a squeegee lifting device 86. The squeegee moving device 80 includes a pair of slide rails 88 and a slider 90. The pair of slide rails 88 are arranged above the mask holding device 22 so as to be parallel to each other and extend in the Y direction. The slider 90 is slidably attached to the pair of slide rails 88, and slides in the Y direction by the operation of an electromagnetic motor (see FIG. 3). Each of the pair of squeegees 82, 84 is generally plate-shaped and made of a flexible material. The pair of squeegees 82, 84 face each other and are arranged so as to extend in the X direction, and are held by the squeegee lifting device 86 below the slider 90. The squeegee lifting device 86 raises and lowers the pair of squeegees 82, 84 individually.

[0016] Solder supply device 26 is a device that supplies cream solder, and a discharge port 96 for discharging cream solder is formed on the bottom surface of solder supply device 26. Solder supply device 26 is fixed to approximately the center of the side surface in the Y direction of slider 90. As a result, solder supply device 26 can be moved to any position in the Y direction by operation of squeegee moving device 80.

[0017] As shown in Fig. 3, the control device 28 includes a controller 100, a plurality of drive circuits 102, and an image processing device 106. The plurality of drive circuits 102 are connected to the electromagnetic motors 36, 72, 76, 92, the board lifting device 32, the adjustment device 56, the squeegee lifting device 86, and the solder supply device 26. The controller 100 includes a CPU, a ROM, a RAM, and the like, and is mainly a computer, and is connected to the plurality of drive circuits 102. As a result, the operation of the transport device 20, the squeegee device 24, and the like is controlled by the controller 100. The controller 100 is also connected to the image processing device 106. The image processing device 106 processes the image data obtained by the upper camera 62 or the lower camera 64, and the controller 100 acquires various information from the image data.

[0018] In the printer 10, with the above-mentioned configuration, the circuit board 38 is transported to a predetermined position and is raised by the board lifting device 32 so that it comes into close contact with the lower surface of the mask 50 held by the mask holding device 22. The mask 50 has through holes (not shown) formed in accordance with the pattern of the pads, etc., of the circuit board 38. Then, cream solder is applied to the mask 50, so that the cream solder is printed on the circuit board 38 through the through holes in the mask 50.

[0019] Specifically, the circuit board 38 is carried into the printing machine 10 and transported to a predetermined position. Then, the X-slider 70 is driven by the camera moving device 60 to move above the circuit board 38, and the lower camera 64 attached to the X-slider 70 captures an image of the circuit board 38 transported to the predetermined position. A fiducial mark (not shown) is marked on the upper surface of the circuit board 38, and the position of the fiducial mark is analyzed by the controller 100 based on the captured image data. This allows the stop position of the circuit board 38 to be calculated. In addition, the upper camera 62 attached to the X-slider 70 captures an image of the mask 50. A fiducial mark (not shown) is also marked on the lower surface of the mask 50, and the position of the fiducial mark is analyzed by the controller 100 based on the captured image data. This allows the holding position of the mask 50 by the mask holding device 22 to be calculated. Then, based on the calculated holding position of the mask 50 and the stop position of the circuit board 38, the holding position of the mask 50 by the mask holding device 22 is adjusted by the adjustment device 56. At this time, the holding position of the mask 50 by the mask holding device 22 is adjusted so that the planned position on the circuit board 38 where the cream solder is to be applied and the through-holes of the mask 50 coincide in the up-down direction, i.e., in the Z direction.

[0020] Then, the Y slider 68 retreats from above the board lifting device 32, and the circuit board 38 is lifted by the drive of the board lifting device 32. As a result, the circuit board 38 comes into close contact with the lower surface of the mask 50. Next, the solder supply device 26 supplies cream solder to the upper surface of the mask 50. Next, one of the pair of squeegees 82, 84 is lowered by the squeegee lifting device 86, and the tip of the lowered squeegee comes into contact with the upper surface of the mask 50. Then, the squeegee is moved in the Y direction by the squeegee moving device 80, and the cream solder is scraped off by the squeegee. At this time, the cream solder is filled inside the through holes of the mask 50 and printed on the circuit board 38. This completes the printing operation on the circuit board 38.

[0021] In this way, the printer 10 adjusts the holding position of the mask 50 based on the imaging data of the fiducial marks of the circuit board 38 and the mask 50, and brings the circuit board 38 and the mask 50 into close contact with each other, so that the cream solder can be appropriately applied to the intended application position of the circuit board 38. However, if the optical axis of the camera that captures the fiducial marks of the circuit board 38 and the mask 50 is deviated from the vertical direction, the circuit board 38 and the mask 50 cannot be brought into close contact with each other at an appropriate position, and the cream solder may not be appropriately applied to the intended application position of the circuit board 38. Alternatively, the same problem occurs when the drive shaft of the board lifting device 32 that lifts and lowers the circuit board 38 is inclined with respect to the vertical direction. For this reason, it is necessary to calculate the amount of deviation between the circuit board 38 and the mask 50 in a state where the circuit board 38 and the mask 50 are in close contact with each other, that is, in a state where the plates are aligned.

[0022] Therefore, in the conventional method, a vernier-shaped pattern is written on each of a glass jig substrate and a glass jig mask, and the amount of misalignment between the jig substrate and the jig mask is calculated based on the image data obtained when the jig substrate and the jig mask are aligned. Specifically, when the jig substrate on which the vernier-shaped pattern is written and the jig mask on which the vernier-shaped pattern is written are aligned, the vernier on the jig substrate and the vernier on the jig mask overlap as one vernier 120, as shown in FIG. 4. Then, the amount of misalignment between the jig substrate and the jig mask is calculated by calculating the amount of misalignment of the other verniers using the vernier 120 as a reference. However, as shown in FIG. 5, the vernier on the jig substrate and the vernier on the jig mask may overlap as two verniers 122, 124. In such a case, the amount of misalignment between the jig substrate and the jig mask is calculated using one of the two verniers 122, 124 as a reference, but the vernier used as the reference is determined by the operator. For this reason, the reference vernier differs depending on the worker, which causes variation in the calculated amount of misalignment between the jig substrate and the jig mask.

[0023] Also, for example, circles of different sizes are printed on a glass jig substrate and a glass jig mask, and the jig substrate and the jig mask are aligned in a printing machine so that the circles overlap. A camera is disposed above the mask holding device 22, and the jig substrate and the jig mask in the aligned state are imaged by the camera. Then, the amount of misalignment between the circle marks on the jig substrate and the circle marks on the jig mask is calculated based on the image data, and the amount of misalignment between the jig substrate and the jig mask can be calculated based on the amount of misalignment. However, even in this case, if the optical axis of the camera is misaligned from the vertical direction, the amount of misalignment cannot be calculated appropriately, and therefore calibration of the optical axis of the camera is required. Also, a camera installation and a camera moving device for changing the imaging position of the camera are required, which increases costs.

[0024] In view of this, in the printing machine 10, a glass jig substrate 150 shown in FIG. 6 and a glass jig mask 160 shown in FIG. 7 are used to calculate the amount of misalignment between the jig substrate 150 and the jig mask 160. Specifically, as shown in FIG. 6, the jig substrate 150 is generally rectangular, and two sets of reference patterns 170 are marked at two corners facing each other across the center of the jig substrate 150. The two sets of reference patterns 170 are symmetrically arranged across the center of the jig substrate 150. When distinguishing between the two sets of reference patterns 170, one of the two sets of reference patterns 170 is described as a reference pattern 170a, and the other is described as a reference pattern 170b.

[0025] Since the two sets of reference patterns 170 have the same shape, one set of reference patterns 170 is shown and described in FIG. 8. The reference pattern 170 is composed of four reference marks 172 to 178, namely, a first reference mark 172, a second reference mark 174, a third reference mark 176, and a fourth reference mark 178. The four reference marks 172 to 178 are arranged on a circumference, and the distance between the centers of two adjacent reference marks is the same. Therefore, the centers of the four reference marks 172 to 178 are located at the vertices of a square. Note that a square is a quadrangle whose four corners are all the same and whose four sides are all the same length, and a rectangle is a quadrangle whose four corners are all the same. Therefore, a square in this specification is a concept that is included in a rectangle.

[0026] The four reference marks 172 to 178 are arranged so that a straight line connecting the center of the first reference mark 172 and the center of the second reference mark 174 and a straight line connecting the center of the third reference mark 176 and the center of the fourth reference mark 178 are perpendicular to each other. Furthermore, the four reference marks 172 to 178 are circular, and the first reference mark 172, the second reference mark 174, and the third reference mark 176 are the same shape, but the fourth reference mark 178 is a larger round shape than the first reference mark 172, the second reference mark 174, and the third reference mark 176. Note that the four reference marks 172 to 178 are shown as white circles in FIG. 7, but are written as black circles on the jig substrate 150. Also, the circles, squares, and straight lines shown by two-dot chain lines in FIG. 8 are virtual lines.

[0027] 6, not only the two sets of reference patterns 170 but also two fiducial marks 180 are marked on the jig substrate 150. The two fiducial marks 180 are marked on two corners different from the two corners on which the two sets of reference patterns 170 are marked, and are symmetrically arranged on either side of the center of the jig substrate 150.

[0028] 7, the jig mask 160 is generally rectangular, and two sets of measurement patterns 190 are marked at two corners facing each other across the center of the jig mask 160. These two sets of measurement patterns 190 are symmetrically arranged across the center of the jig mask 160. When distinguishing between the two sets of measurement patterns 190, one of the two sets of measurement patterns 190 is described as measurement pattern 190a, and the other is described as measurement pattern 190b.

[0029] Each of the two sets of measurement patterns 190 is composed of only a measurement mark 192. The measurement mark 192 is circular and is larger than the fourth reference mark 178 of the reference pattern 170. The measurement mark 192 is written on the jig mask 160 so as to be positioned at the center of the four reference marks 172 to 178 of the reference pattern 170 when the jig mask 160 is superimposed on the jig substrate 150. That is, the measurement mark 192 is large enough to be placed in the internal area surrounded by the four reference marks 172 to 178 without contacting any of the four reference marks 172 to 178. The measurement pattern 190a corresponds to the reference pattern 170a, and the measurement pattern 190b corresponds to the reference pattern 170b. For this reason, the measurement mark 192 of the measurement pattern 190a is written on the jig mask 160 so as to be positioned at the center of the four reference marks 172 to 178 of the reference pattern 170a. Furthermore, measurement marks 192 of measurement pattern 190b are marked on jig mask 160 so as to be positioned at the centers of four reference marks 172 to 178 of reference pattern 170b.

[0030] In addition to the two sets of measurement patterns 190, the jig mask 160 also has two fiducial marks 196. The two fiducial marks 196 are marked at two corners different from the two corners at which the two sets of measurement patterns 190 are marked, and are symmetrically arranged with respect to the center of the jig mask 160.

[0031] In this way, the jig substrate 150 on which the reference pattern 170 is written and the jig mask 160 on which the measurement pattern 190 is written are aligned in the printing press 10. That is, in the printing press 10, the jig mask 160 is held by the mask holding device 22. The jig substrate 150 is also carried into the printing press 10 and transported to a predetermined position. Then, the X-slider 70 is driven by the camera moving device 60 to move above the jig substrate 150, and the jig substrate 150 transported to the predetermined position is imaged by the lower camera 64 attached to the X-slider 70. Then, based on the image data, the position of the fiducial mark 180 is analyzed by the controller 100, and the stop position of the jig substrate 150 is calculated. The jig mask 160 is also imaged by the upper camera 62 attached to the X-slider 70. Then, based on the imaging data, the position of the fiducial mark 196 is analyzed by the controller 100, and the holding position of the jig mask 160 by the mask holding device 22 is calculated. Then, based on the calculated holding position of the jig mask 160 and the stop position of the jig substrate 150, the holding position of the jig mask 160 by the mask holding device 22 is adjusted by the adjustment device 56. Then, the Y slider 68 retreats from above the substrate lifting device 32, and the jig substrate 150 is raised by the driving of the substrate lifting device 32, so that the jig substrate 150 comes into close contact with the lower surface of the jig mask 160. This completes the plate alignment work between the jig substrate 150 and the jig mask 160.

[0032] Then, when the plate alignment work between the jig substrate 150 and the jig mask 160 is completed, an operator uses a camera (not shown) to capture an image of the jig substrate 150 and the jig mask 160 in the aligned state from above the printing press 10. That is, an operator uses a camera to capture an image of the jig mask 160 placed on the jig substrate 150 from above the jig mask 160. Note that the camera is not provided in the printing press 10, and an operator captures an image of the jig mask 160 by hand.

[0033] Then, when the worker inputs the imaging data obtained by imaging to the control device 28, the imaging data is analyzed in the control device 28. Specifically, since the jig substrate 150 and the jig mask 160 are made of glass, the four reference marks 172 to 178 of the reference pattern 170 and the measurement mark 192 of the measurement pattern 190 are reflected in the image based on the imaging data, as shown in FIG. 9. Then, in the control device 28, the positions of the four reference marks 172 to 178 are first calculated based on the imaging data. At this time, the positions of the reference marks are calculated as coordinate positions in pixel units in the imaging data. Then, since the fourth reference mark 178 is larger than the first reference mark 172, the second reference mark 174, and the third reference mark 176, the relative position of the fourth reference mark 178 with respect to the first reference mark 172, the second reference mark 174, and the third reference mark 176 is specified. At this time, the orientation of the image based on the imaging data is specified based on the relative position of the fourth reference mark 178. 9, the orientation of the image based on the imaging data is changed so that the fourth reference mark 178 of the four reference marks 172 to 178 is positioned at the rightmost position. This makes it possible to keep the orientation of the image based on the imaging data constant regardless of the imaging direction when the worker images the jig substrate 150 and the jig mask 160 in the plate-aligned state.

[0034] Next, the tilt angle of the line connecting third reference mark 176 and fourth reference mark 178 is calculated based on the positions of third reference mark 176 and fourth reference mark 178. Specifically, for example, when the center position of third reference mark 176 is (X3, Y3) and the center position of fourth reference mark 178 is (X4, Y4), the tilt angle α of the line connecting third reference mark 176 and fourth reference mark 178 is calculated based on the following formula. tan α = (Y4-Y3) / (X4-X3) Then, since the calculated inclination angle α of the straight line is the inclination angle of the image based on the imaging data, the image based on the imaging data is rotated by the calculated inclination angle α. As a result, the straight line connecting the center of the third reference mark 176 and the center of the fourth reference mark 178 can be set as the X-axis, and the straight line connecting the center of the first reference mark 172 and the center of the second reference mark 174 can be set as the Y-axis.

[0035] Next, the number of pixels between the center of the third fiducial mark 176 and the center of the fourth fiducial mark 178 (hereinafter referred to as the "X-direction pixel number") is calculated. In addition, the distance between the center of the third fiducial mark 176 and the center of the fourth fiducial mark 178 on the jig substrate 150 (hereinafter referred to as the "X-direction distance") is measured in advance, and the distance is stored in the control device 28. Therefore, the distance per unit pixel in the direction in which the third fiducial mark 176 and the fourth fiducial mark 178 are aligned, that is, in the X-direction, is calculated. Specifically, for example, when the number of pixels in the X-direction is 100 pixels and the X-direction distance is 10 mm, the distance per unit pixel in the X-direction (=10 mm / 100 pixels) is calculated.

[0036] Furthermore, the number of pixels between the center of the first reference mark 172 and the center of the second reference mark 174 (hereinafter referred to as the "Y direction pixel number") is calculated. Also, the distance between the center of the first reference mark 172 and the center of the second reference mark 174 on the jig substrate 150 (hereinafter referred to as the "Y direction distance") is measured in advance, and the distance is stored in the control device 28. Therefore, the distance per unit pixel in the direction in which the first reference mark 172 and the second reference mark 174 are aligned, that is, in the Y direction, is calculated. Specifically, for example, when the number of pixels in the Y direction is 102 pixels and the Y direction distance is 10 mm, the distance per unit pixel in the Y direction (=10 mm / 102 pixels) is calculated.

[0037] If the X-direction distance and the Y-direction distance are the same, the calculated X-direction pixel number and Y-direction pixel number should be the same, but if the optical axis of the camera at the time of imaging the jig substrate 150 is deviated from the vertical direction, the calculated X-direction pixel number and Y-direction pixel number will be different values. Therefore, by calculating the distance per unit pixel in the X-direction and Y-direction by the above-mentioned method, even if the optical axis of the camera at the time of imaging the jig substrate 150 is deviated from the vertical direction, the amount of deviation between the jig substrate 150 and the jig mask 160 can be properly calculated. Furthermore, even if the number of pixels of the camera used at the time of imaging the jig mask 160 is unknown, the number of pixels is calculated based on the imaging data, so the amount of deviation can be properly calculated without inputting the number of pixels to the control device 28.

[0038] Specifically, the center position of the four reference marks 172-178 (hereinafter, referred to as the "calculated center position") is calculated based on the previously calculated positions of the four reference marks 172-178. Also, the center position of the measurement mark 192 is calculated based on the captured image data. At this time, if the jig substrate 150 and the jig mask 160 are accurately aligned, the calculated center position and the center position of the measurement mark 192 are the same. On the other hand, if the jig substrate 150 and the jig mask 160 are aligned in a misaligned state, the difference between the calculated center position and the center position of the measurement mark 192 is the amount of misalignment between the jig substrate 150 and the jig mask 160. Note that the amount of misalignment between the jig substrate 150 and the jig mask 160 is calculated as the amount of misalignment in the X direction and the Y direction, and is therefore, for example, (ΔX, ΔY). In addition, since the amount of misalignment between the jig substrate 150 and the jig mask 160 is the amount of misalignment in the coordinate position of each pixel in the image data, the amount of misalignment calculated based on the difference between the calculation center position and the center position of the measurement mark 192 is described as the pixel-unit misalignment amount (ΔXG, ΔYG).

[0039] Then, the displacement amount per pixel (ΔXG, ΔYG) is multiplied by the distance per unit pixel (mm / pixel) previously calculated to calculate the displacement amount per distance (ΔXK, ΔYK). In other words, the displacement amount per pixel in the X direction ΔXG is multiplied by the distance per unit pixel in the X direction (=10 mm / 100 pixels) to calculate the displacement amount per distance ΔXK in the X direction. Also, the displacement amount per pixel in the Y direction ΔYG is multiplied by the distance per unit pixel in the Y direction (=10 mm / 102 pixels) to calculate the displacement amount per distance ΔYK in the Y direction.

[0040] In this way, by calculating the amount of deviation per distance (ΔXK, ΔYK) using the distance per unit pixel (mm / pixel) in each of the X and Y directions, the difference in the number of pixels in the X and Y directions caused by the deviation of the optical axis of the camera is corrected to calculate the amount of deviation per distance (ΔXK, ΔYK). In other words, even if the optical axis of the camera is deviated from the vertical direction when the jig substrate 150 is imaged, the distance (ΔXK) by which the jig substrate 150 and the jig mask 160 are actually shifted in the X direction and the distance (ΔYK) by which they are shifted in the Y direction are calculated.

[0041] The distance unit deviation (ΔXK, ΔYK) is calculated for each of the combination of reference pattern 170a and measurement pattern 190a and the combination of reference pattern 170b and measurement pattern 190b. That is, a first distance unit deviation (ΔXK1, ΔYK1) is calculated based on the difference between the position of measurement mark 192 in measurement pattern 190a and the calculation center position of four reference marks 172-178 in reference pattern 170a. A second distance unit deviation (ΔXK2, ΔYK2) is calculated based on the difference between the position of measurement mark 192 in measurement pattern 190b and the calculation center position of four reference marks 172-178 in reference pattern 170b.

[0042] In this way, when the first distance unit deviation amount and the second distance unit deviation amount are calculated, the first distance unit deviation amount is associated with the calculation center position used when calculating the deviation amount, and the second distance unit deviation amount is associated with the calculation center position used when calculating the deviation amount. That is, the first distance unit deviation amount is associated with the calculation center position of the four reference marks 172-178 of the reference pattern 170a, and the second distance unit deviation amount is associated with the calculation center position of the four reference marks 172-178 of the reference pattern 170b. In addition, the position coordinates of the center of the jig mask 160 (hereinafter referred to as "mask center coordinates") are calculated based on the imaging data. Then, the amount of misalignment in the X-direction and the Y-direction at the mask center coordinates and the rotation angle of the jig mask 160 centered on the mask center coordinates are calculated based on a combination of the first amount of misalignment in distance units and the calculation center position of the reference pattern 170a, and a combination of the second amount of misalignment in distance units and the calculation center position of the reference pattern 170b. Note that this calculation method is the same as the method for calculating the amount of misalignment and the rotation angle of a mask, etc., based on a fiducial mark, and is a well-known method, so a detailed description will be omitted. Incidentally, the rotation angle of the jig mask 160 is the relative rotation angle between the jig substrate 150 and the jig mask 160.

[0043] Then, the holding position of the jig mask 160 by the mask holding device 22 is adjusted by the adjustment device 56 based on the calculated misalignment amount in the X direction and the Y direction at the mask center coordinate and the rotation angle of the jig mask 160, so that the jig board 150 and the jig mask 160 can be accurately aligned. That is, during the actual application of cream solder, the holding position of the mask 50 by the mask holding device 22 is adjusted by the adjustment device 56 based on the calculated misalignment amount in the X direction and the Y direction and the rotation angle, so that the mask 50 and the circuit board 38 can be accurately aligned. Specifically, the controller 100 stores in advance the calculated misalignment amount in the X direction and the Y direction at the mask center coordinate and the rotation angle of the jig mask 160. During the actual application of cream solder, the lower camera 64 captures an image of the fiducial mark of the circuit board 38 carried into the printer 10. The controller 100 calculates the amount of misalignment and rotation angle in the X and Y directions to be adjusted by the adjustment device 56 by adding the amount of misalignment and rotation angle stored in advance to the values ​​calculated based on the imaging data of the fiducial mark on the circuit board 38 and the imaging data of the fiducial mark on the mask 50 captured by the upper camera 62.

[0044] In this way, by calculating the amount of deviation per distance using the jig substrate 150 on which the reference pattern 170 is written and the jig mask 160 on which the measurement pattern 190 is written, it is possible to prevent the variation in the amount of deviation for each worker that occurs when using a jig substrate and a jig mask on which a vernier is written. In addition, by using the jig substrate 150 and the jig mask 160, it is possible to properly calculate the amount of deviation per distance in the X direction and the Y direction even if the optical axis of the camera at the time of imaging is deviated from the vertical direction. Therefore, even if a camera and a camera moving device are not provided in the printing press 10, it is possible for the worker to take an image by hand, and the cost of the device can be reduced. In other words, even in a printing press that does not have a camera for taking an image of the jig substrate 150 and the jig mask 160 in the plate-aligned state, it is possible to properly calculate the amount of deviation per distance.

[0045] In the above embodiment, the control device 28 is an example of a calculation device. The jig substrate 150 is an example of a substrate. The jig mask 160 is an example of a mask. The first reference mark 172 is an example of a first mark. The second reference mark 174 is an example of a second mark. The third reference mark 176 is an example of a third mark. The fourth reference mark 178 is an example of a fourth mark. The measurement mark 192 is an example of a fifth mark.

[0046] The present invention is not limited to the above embodiment, and can be embodied in various forms with various modifications and improvements based on the knowledge of a person skilled in the art. Specifically, for example, in the above embodiment, the four reference marks 172 to 178 are marked on the jig substrate 150 so as to be located at the vertices of a square, but the four reference marks may be marked on the jig substrate 150 so as to be located at the vertices of a rectangle. Specifically, as shown in FIG. 10, the centers of the four reference marks 200 to 206, namely, the first reference mark 200, the second reference mark 202, the third reference mark 204, and the fourth reference mark 206, are arranged on a circumference, and the straight lines connecting the centers of two adjacent reference marks are perpendicular to each other. Therefore, the centers of the four reference marks 200 to 206 are located at the vertices of a rectangle. Note that the straight line connecting the center of the first reference mark 200 and the center of the second reference mark 202 is perpendicular to the straight line connecting the center of the second reference mark 202 and the center of the fourth reference mark 206. Therefore, when these four reference marks 200-206 are used, the image based on the imaging data is rotated so that the straight line connecting the center of the first reference mark 200 and the center of the second reference mark 202 becomes the X-axis, and the straight line connecting the center of the second reference mark 202 and the center of the fourth reference mark 206 becomes the Y-axis.

[0047] In the above embodiment, the inclination angle of the line connecting the center of the third reference mark 176 and the center of the fourth reference mark 178 is calculated, but the inclination angle of the line connecting the center of the first reference mark 172 and the center of the second reference mark 174 may be calculated. In such a case, the image based on the imaging data is rotated based on the inclination angle of the line connecting the center of the first reference mark 172 and the center of the second reference mark 174.

[0048] In addition, in the above embodiment, the reference pattern 170 is marked on the jig substrate 150 and the measurement pattern 190 is marked on the jig mask 160, but the measurement pattern 190 may be marked on the jig substrate 150 and the reference pattern 170 may be marked on the jig mask 160.

[0049] In addition, although the jig substrate 150 and the jig mask 160 are made of glass, they may be made of a material other than glass that transmits light. In addition, the jig substrate 150 and the jig mask 160 may be made of a material that does not transmit light. In such a case, a through hole is formed in the jig mask so that the mark written on the jig substrate is exposed. As a result, when the jig substrate and the jig mask are aligned, the mark written on the jig substrate and the mark written on the jig substrate are exposed from the viewpoint from above.

[0050] Furthermore, in the above embodiment, the holding position of the mask 50 is adjusted by the adjustment device 56, but the holding position of the circuit board 38 may be adjusted by an adjustment mechanism. That is, the relative misalignment amounts in the X and Y directions between the jig board 150 and the jig mask 160 and the relative rotation angle between the jig board 150 and the jig mask 160 are calculated, and the position of at least one of the circuit board 38 and the mask 50 is adjusted based on the calculated relative misalignment amount and rotation angle.

[0051] In addition, in the above embodiment, the various types of calculation processing described above are executed in the control device 28 of the printing press 10, but the various types of calculation processing described above may be executed in an information processing device external to the printing press 10. In such a case, the calculated amount of deviation and the like are input to the control device 28, whereby the operation of the adjustment device 56 is controlled.

[0052] In the above embodiment, the jig substrate 150 and the jig mask 160 in the plate-aligned state are imaged by an operator, but a camera may be disposed above the mask holding device 22, and the jig substrate 150 and the jig mask 160 in the plate-aligned state may be imaged by the camera. In such a case, the accuracy of the optical axis of the camera in the vertical direction may be low. [Explanation of symbols]

[0053] 28: control device (arithmetic device) 150: jig substrate (substrate) 160: jig mask (mask) 172: first reference mark (first mark) 174: second reference mark (second mark) 176: third reference mark (third mark) 178: fourth reference mark (fourth mark) 192: measurement mark (fifth mark)

Claims

1. When four marks are marked on one of the substrate and the mask so as to be located at the vertices of a rectangle, a line connecting a first mark and a second mark of the four marks is perpendicular to a line connecting a third mark and a fourth mark of the four marks, and a fifth mark is marked on the other of the substrate and the mask, a calculation device that uses imaging data of a substrate and a mask in which the five marks are exposed and the fifth mark is positioned at the center of the four marks, and calculates a tilt of an image based on the imaging data based on the first mark and the second mark, or the third mark and the fourth mark, and calculates an amount of positional misalignment between the center of the four marks and the fifth mark after correcting a difference in the number of pixels caused by a misalignment of the optical axis of a camera that captured the image, based on a distance per unit pixel in a direction in which the first mark and the second mark are aligned and a distance per unit pixel in a direction in which the third mark and the fourth mark are aligned.

2. the first mark, the second mark, and the third mark have the same shape, and the fourth mark has a shape different from the first mark, the second mark, and the third mark, The computing device according to claim 1 , further comprising: a computing device configured to compute an orientation of an image based on the imaging data, based on a position of the fourth mark in the imaging data.

3. When two sets of the four marks are marked on one of the substrate and the mask, and two sets of the fifth marks are marked on the other of the substrate and the mask, 3. The calculation device according to claim 1, wherein a rotation angle between the substrate and the mask is calculated based on an amount of positional misalignment between a center of one of the two sets of four marks and a fifth mark of one of the two fifth marks, and an amount of positional misalignment between a center of the other of the two sets of four marks and a fifth mark of the other of the two fifth marks.

4. When four marks are marked on one of the substrate and the mask so as to be located at the vertices of a rectangle, a line connecting a first mark and a second mark of the four marks is perpendicular to a line connecting a third mark and a fourth mark of the four marks, and a fifth mark is marked on the other of the substrate and the mask, a calculation method for calculating an amount of positional deviation between the center of the four marks and the fifth mark after correcting a difference in the number of pixels caused by a deviation of the optical axis of a camera that captured the image, based on a distance per unit pixel in a direction in which the first mark and the second mark are aligned and a distance per unit pixel in a direction in which the third mark and the fourth mark are aligned, using imaging data of a substrate and a mask that are overlapped so that the fifth mark is located at the center of the four marks, and based on the distance per unit pixel in a direction in which the first mark and the second mark are aligned and the distance per unit pixel in a direction in which the third mark and the fourth mark are aligned.

Images