JP7766014B2 - Tiling Device - Google Patents

Description

The present invention relates to a tiling device.

In recent years, development has been progressing on modules that incorporate multiple rows and columns of light-emitting diode (LED) elements on the order of tens to hundreds of micrometers. Arranging such modules in multiple rows and columns to manufacture display devices and lighting devices is being considered.

Japanese Patent Application Laid-Open No. 2021-9937

When tiling LED modules equipped with multiple LED elements as described above in multiple rows and columns (hereinafter also referred to as "tiling"), for example, images of the alignment marks on the LED modules and the alignment marks on the substrate are captured, and the two are aligned based on the captured images.

In this type of alignment, the accuracy of position recognition during imaging is important. For example, the positional relationship between the camera capturing the image of the LED module and the camera capturing the image of the board can be a source of error. For example, thermal expansion or vibration can change the positional relationship between the cameras and the positional relationship in the captured image, making it difficult to align the LED module and board with high precision.

The present invention aims to provide a tiling device that can tile modules on a substrate with high precision.

The tiling device of the present invention comprises a stage that supports a substrate; a head that transports a module mounted with multiple elements to a position facing the substrate; an imaging unit that faces the substrate through the module held by the head and captures images of a first alignment mark provided on the substrate and a second alignment mark provided on the module within the same field of view; and a focal length adjustment unit that is provided on an optical path connecting the first alignment mark and the imaging unit and adjusts the focal length of the imaging unit with respect to the first alignment mark so that the imaging unit is focused on the first alignment mark and the second alignment mark simultaneously. The head tiled the module on the substrate based on the image captured by the imaging unit.

The tiling device of the present invention can tile modules on a substrate with high precision.

FIG. 2 is a plan view showing a substrate according to the embodiment. 1A and 1B are a plan view and a side view showing a module according to an embodiment of the present invention; FIG. 2 is a plan view showing a supply table and a tiling device according to the embodiment. FIG. 1 is a side view showing a tiling device according to an embodiment. 1A and 1B are schematic diagrams illustrating a pickup state in an embodiment ((A) before alignment, (B) during pickup, and (C) after pickup). FIG. 10 is a diagram illustrating a tiling procedure according to an embodiment. FIG. 2 is a block diagram showing a control device according to the embodiment. 10 is a flowchart illustrating a tiling procedure according to an embodiment. 3A and 3B are diagrams illustrating an imaging field of view of an imaging unit according to an embodiment. 10A and 10B are diagrams illustrating the direction in which modules should be tiled according to an embodiment. 10A, 10B, and 10C are side views showing a focal length adjustment unit according to a modified example.

An embodiment of the present invention (hereinafter referred to as this embodiment) will be described in detail with reference to the drawings. First, the substrate and module will be described, and then the tiling device will be described. Note that each figure is a schematic representation of this embodiment.

[substrate]
As shown in FIG. 1 , the substrate 1 of this embodiment is a substrate for a display device, and modules 2 (described later) are tiled on its surface. Alignment marks M are provided on the surface of the substrate 1 to align and tile the modules 2 at desired positions. The alignment marks M are provided at positions corresponding to the alignment marks m provided on the modules 2. That is, the alignment marks M and m are marks that serve as references for tiling the modules 2 on the substrate 1. In this embodiment, four alignment marks M are provided for each module 2, corresponding to the alignment marks m provided at each of the four corners of the square module 2 (the module 2 is indicated by dotted lines in FIG. 1 ). That is, a set of four alignment marks M is provided so as to be located at the vertices of a square. These sets of four alignment marks M are provided in multiple rows and multiple columns on the surface of the substrate 1, thereby enabling tiling of the modules 2 on the substrate 1. FIG. 1 shows that alignment marks M are provided so that four modules 2 can be tiled on the substrate 1. The surface of the substrate 1 is covered with a thin adhesive layer (not shown), and the substrate 1 and the module 2 are bonded via this adhesive layer. Note that the four corners and vertices include their vicinities.

[Module]
2A and 2B, the module 2 that is the target of tiling in this embodiment includes a flexible substrate 21, an alignment mark m provided on the surface of the flexible substrate 21, a plurality of light-emitting elements 22 mounted on the surface of the flexible substrate 21, and a sealing member 23 that seals the alignment mark m and the light-emitting elements 22. The module 2 is tiled on the surface of the substrate 1 by a tiling device 3, which will be described later.

The flexible substrate 21 is made of, for example, polyimide, and has a light-emitting element 22 mounted on its surface. As shown in FIG. 2(A), the flexible substrate 21 of this embodiment is square in plan view, and alignment marks m are provided at the four corners of the flexible substrate 21 to correspond to the alignment marks M on the substrate 1, for aligning the module 2 to the substrate 1. That is, the set of four alignment marks m is provided so as to be located at the vertices of the square. Note that in this embodiment, four sets of alignment marks M, m are provided, but only two sets are actually used for alignment, as described below. Therefore, the number of sets of alignment marks M, m may be two. Note that the four corners and vertices include their vicinity.

The light-emitting elements 22 are LED elements, and multiple elements are mounted on the surface of the flexible substrate 21. In this embodiment, the light-emitting elements 22 are LED elements on the order of micrometers, with a height of, for example, approximately 25 μm.

As shown in FIG. 2(B), the sealing member 23 is a transparent resin member that seals the alignment mark m and light-emitting element 22 provided on the surface of the flexible substrate 21. The sealing member 23 can be made of, for example, a thermosetting resin with a viscosity of approximately 4000 mPa·s before hardening. The sealing member 23 can be formed by hardening a curable resin supplied to the surface of the module 2 on which the light-emitting element 22 is mounted. The thickness of the sealing member 23 is, for example, 50 to 300 μm. Because the sealing member 23 is a transparent resin member as described above, the alignment mark m and light-emitting element 22 can be seen through the sealing member 23.

[Tiling device]
[composition]
As shown in FIGS. 3 and 4 , the tiling device 3 includes a housing C, a supply table S, a stage 31, a head 32, a moving mechanism 320, an imaging unit 33, a focal length adjustment unit 34, and a control device 8. The housing C houses the supply table S, the stage 31, the head 32, the moving mechanism 320, and the control device 8 therein. The supply table S is movably mounted, supports the module 2, and supplies the module 2 to the tiling device 3. The stage 31 is movably mounted, and supports the substrate 1. The head 32 works in cooperation with the moving mechanism 320 to transfer the module 2 from the supply table S to the substrate 1. At this time, the imaging unit 33 captures images of the alignment mark M on the substrate 1 and the alignment mark m on the module 2 directly and/or via the focal length adjustment unit 34. Based on the image capture results, the moving mechanism 320 and the stage 31 align and place the module 2 at the placement position of the substrate 1, and tile the module 2. The control device 8 controls each component (see FIG. 6 ). In FIG. 3, the focal length adjustment unit 34 is omitted.

In Figure 3, the direction in which the supply table S and stage 31 are aligned is the X direction, the direction perpendicular to the X direction in a plane parallel to the surface of the stage 31 is the Y direction, and the direction perpendicular to the X and Y directions is the Z direction. The Z direction is the direction penetrating the paper in the figure. In this embodiment, the tiling device 3 is installed so that the Z direction is vertical, and therefore the XY plane is a horizontal plane. In this case, the Z direction is the height direction, with the installation surface side referred to as downward and the opposite side as upward. In other words, downward is the direction of gravity. The rotation direction parallel to the XY plane is referred to as the θ direction.

The supply table S has a flat surface and is a support table that supports one or more modules 2 on the surface. In this embodiment, as shown in FIG. 3, the supply table S supports four modules 2. The supply table S is movable in the Y direction by a linear motion mechanism (not shown) and moves back and forth between the inside and outside of the housing C. This allows the supply table S to transport modules 2 to be tiled onto the substrate 1 from the outside of the housing C to the inside of the housing C. As will be described later, the supply table S works in cooperation with the movement mechanism 320 to move the module 2 to face the head 32 so that the module 2 to be picked up can be picked up by the head 32. The linear motion mechanism (not shown) is composed of, for example, a motor, a linear guide, and a ball screw, and the surface of the supply table S is supported by the slider of this linear guide. A separate loading device such as a robot may be provided to load modules 2 onto the supply table S from outside the tiling device 3. At this time, the modules 2 may be loaded one by one, or multiple modules 2 may be loaded all at once using a tray.

The stage 31 has a flat surface and is a support platform that supports the substrate 1 on the surface. In this embodiment, the stage 31 supports one substrate 1, as shown in FIG. 3 . The stage 31 is movable in the Y direction by a linear motion mechanism (not shown), and moves back and forth between the inside and outside of the housing C. This allows the stage 31 to transport the substrate 1 from the outside of the housing C to the inside of the housing C, and to transport the substrate 1 on which the modules 2 are tiled from the inside of the housing C to the outside of the housing C. Furthermore, as described below, the movement mechanism 320 and the stage 31 work together to move the substrate 1 so that the head 32 faces the intended tiling position of the module 2 on the substrate 1, so that the head 32 can place the module 2 at a predetermined position on the substrate 1 and tile it. The linear motion mechanism (not shown) is composed of, for example, a motor, a linear guide, and a ball screw, and the surface of the stage 31 is supported by the slider of this linear guide. A separate unloading device such as a robot may be provided to unload the substrate 1 from the stage 31 to the outside of the tiling device 3.

In this embodiment, the alignment mark M on the surface of the substrate 1 placed on the stage 31 and the alignment mark m on the surface of the module 2 placed on the supply table S are set to the same height. This setting can be achieved by adjusting the height of the support surfaces of the supply table S and stage 31 using an adjustment mechanism (not shown), such as a fine adjustment mechanism using a push-pull screw, depending on the thickness of the flexible substrate 21 of the module 2 and the thickness of the substrate 1.

The head 32 sucks and holds the module 2 supported on the supply table S and tiles it on the substrate 1 supported on the stage 31. As shown in FIG. 4, the head 32 is supported by a linear motion mechanism 321 via an elevating mechanism 322 and is movable between the supply table S and the stage 31 so that the module 2 can be transferred from the supply table S to the stage 31. The linear motion mechanism 321 is composed of, for example, a motor, a linear guide, and a ball screw. It is suspended above the supply table S and the stage 31 and extends to face the surfaces of the supply table S and the stage 31. The linear guide is composed of a rail 321a, a guide 321b, a slider 321c, and a base 321d. The rail 321a is attached to the base 321d so that it can move horizontally. A guide 321b grips the rail 321a, and the guide 321b is attached to the slider 321c. The lifting mechanism 322, which includes, for example, a motor, linear guide, and ball screw, is supported by the slider of the linear motion mechanism 321 and extends in a direction toward and away from the supply table S and stage 31. The linear guide has a slider 322c attached to the side of the head 32, and a guide 322b attached to the slider 322c. A rail 322a is attached to the slider 321c on the linear motion mechanism 321 side to enable vertical movement. The head 32 is supported by the slider of this lifting mechanism 322. The linear motion mechanism 321 and lifting mechanism 322 form the movement mechanism 320. While FIG. 4 shows two rails 321a and two guides 321b, the number may be increased or decreased depending on the size of the base 321d and slider 321c. Similarly, the number of rails 321a and guides 322b may also be increased or decreased.

A holding unit 32a is provided on the side of the head 32 facing the supply table S and stage 31. The holding unit 32a has suction holes (not shown) on the surface facing the supply table S and stage 31, and by generating negative pressure in these suction holes, it is possible to suction-hold and pick up the module 2 from the supply table S. The holding unit 32a can also release the module 2 and tile it onto the substrate 1 by releasing the negative pressure generated in the suction holes. Furthermore, the holding unit 32a is rotatable in the θ direction relative to the head 32 by a θ-direction rotation mechanism (not shown), and can rotate the held module 2 in the θ direction. This allows the holding unit 32a to adjust the orientation of the module 2 when tiling it onto the substrate 1. Note that this θ-direction rotation mechanism is also included in the movement mechanism 320.

The head 32 is provided with a contact sensor (not shown). This contact sensor detects when the holding portion 32a comes into contact with the module 2, or when it comes into contact with the substrate 1 while holding the module 2. The contact sensor is, for example, a gap sensor such as an eddy current sensor. Based on the contact information detected by this contact sensor, the head 32 can suction-hold or release the module 2.

In this embodiment, the holding unit 32a suction-holds the module 2 so that at least two of the alignment marks m provided at the four corners of the module 2 are visible from above. This is achieved by the holding unit 32a suction-holding a portion of the top surface of the module 2 that does not obstruct the alignment marks m from being viewed from above. Furthermore, in this embodiment, a transparent portion 32b made of a transparent material such as quartz glass is provided on the side of the holding unit 32a on the optical path connecting the alignment marks m of the module 2 suction-held by the holding unit 32a and the imaging unit 33. In other words, the imaging unit 33 captures an image of the alignment marks m through this transparent portion 32b. The underside of the transparent portion 32b is set to be at the same height as the underside of the holding portion 32a. As a result, the upper surface (sealing member 23 surface) of the module 2 is supported flatly and entirely by the holding portion 32a and transparent portion 32b, and the head 32 can press the entire upper surface of the module 2 against the substrate 1 when tiling the module 2 on the substrate 1.

The imaging unit 33 is a camera having one optical system, such as a lens, and one imaging element that captures the alignment mark m of the module 2 and the alignment mark M of the substrate 1 in the same field of view. That is, the imaging unit 33 faces the substrate 1 through the module 2 held by the head 32, and is positioned so that it can capture the alignment mark M on the substrate 1 and the alignment mark m on the module 2, which is positioned so as to face the current tiling location on the substrate 1, in the same field of view. The focal length of the imaging unit 33 is set to a predetermined reference height position where the alignment mark m of the module 2 facing the substrate 1 is positioned.

In this embodiment, the imaging units 33 are supported by the linear motion mechanism 321 above the head 32. More specifically, two imaging units 33 are provided, one at each end of a U-shaped frame 33a supported by the linear motion mechanism 321. One side of the frame 33a connecting the two parallel sides of the U-shape is supported by the linear motion mechanism 321, and the frame 33a is movable in the X direction in conjunction with the movement of the head 32 in the X direction. That is, the imaging units 33 are positioned above the alignment marks m and M when the holding portion 32a of the head 32 holds the module 2 and is transported to a position facing the substrate 1. As a result, as shown in FIG. 8 , each imaging unit 33 simultaneously captures corresponding alignment marks m and M within the same field of view. "Capturing images within the same field of view" refers to simultaneously capturing images of multiple objects within the imaging field of view (collectively at one time). Each imaging unit 33 transmits the captured images of alignment mark m and alignment mark M to the control device 8, which will be described later. Each imaging unit 33 is installed at a height position where its focal length matches a predetermined reference height position where alignment mark m of module 2 facing the substrate 1 is positioned.

The focal length adjustment unit 34 is a transparent member such as quartz glass that adjusts the focal length of the imaging unit 33 relative to the alignment mark M of the imaging unit 33 to focus on the alignment mark M. That is, the focal length adjustment unit 34 is located on the optical path connecting the alignment mark M on the substrate 1 and the imaging unit 33, and extends the focal length of the imaging unit 33 to the substrate 1. In this way, the focal length adjustment unit 34 moves the actual focal position away from the imaging unit 33, so that the imaging unit 33 also focuses on the alignment mark M based on the state in which the imaging unit 33 focuses on the alignment mark m of the module 2, which is closer to the imaging unit 33. For example, the predetermined reference height position for the alignment mark m is when the alignment mark m is located 1 mm above the top surface of the substrate 1 on which the alignment mark M is located. In this state, when imaging alignment marks M and m within the same field of view, a focal length adjustment unit 34 with a thickness of approximately 0.3 mm is used on the optical path connecting alignment mark M and imaging unit 33. As shown in FIG. 8 , focal length adjustment unit 34 is disposed so as to cover half of the imaging field of view of imaging unit 33 (the lower side in FIG. 8 ), thereby extending the focal length of the lower half of the imaging field of view of imaging unit 33 compared to the focal length of the remaining half of the imaging field of view (the upper side in FIG. 8 ). In this embodiment, the module 2 held by head 32 and alignment mark m are displayed in the upper half of the imaging field of view of imaging unit 33, as described below. In this way, the focal length adjustment unit 34 fixes and sets the focal length of imaging unit 33 so that both predetermined alignment marks m and M are simultaneously in focus.

The focal length adjustment unit 34 is supported by the linear motion mechanism 321 via a support member (not shown) and is movable in the X direction in conjunction with the movement of the head 32 and imaging unit 33 in the X direction. As a result, as shown by the dashed arrow in Figure 4, the imaging unit 33 can focus on the alignment mark M while still focusing on the alignment mark m of the module 2 held by the head 32 above the substrate 1. Therefore, the image captured by the imaging unit 33 is focused on both the alignment mark m and the alignment mark M, enabling the correction process in the control device 8 (described below) to be performed with high accuracy. In practice, not only the focal length adjustment unit 34 but also the transparent portion 32b extends the focal length of the imaging unit 33. Therefore, the focal length adjustment unit 34 is made of a transparent member that is thicker in the optical path direction connecting the substrate 1 and the imaging unit 33 than the transparent portion 32b.

The control device 8 is a device that controls the tiling device 3. This control device 8 is configured, for example, by a dedicated electronic circuit or a computer that operates on a predetermined program. In other words, the control device 8 controls the operation of the tiling device 3 by controlling the operation of the supply table S, stage 31, head 32, imaging unit 33, etc. As shown in FIG. 6, the control device 8 includes a memory unit 81, an imaging control unit 82, a calculation unit 83, a movement control unit 84, a setting unit 85, and an input/output control unit 86.

The memory unit 81 is a storage medium such as an HDD or SSD. The memory unit 81 pre-stores data and programs necessary for system operation, and also stores data necessary for system operation. The imaging control unit 82 controls the operation of the imaging unit 33. In other words, it controls imaging-related operations such as starting up the imaging unit 33, capturing images, stopping images, transmitting images, and focusing. The calculation unit 83 calculates the amount of deviation between the alignment marks M and m based on the captured images received from the imaging unit 33, and transmits the calculated amount of deviation to the movement control unit 84.

The movement control unit 84 controls the movement of the supply table S, stage 31, and movement mechanism 320. This control is based on data and programs necessary for system operation that are pre-stored in the memory unit 81, images captured by the imaging unit 33, and calculation results from the calculation unit 83. In particular, the movement control unit 84 of this embodiment controls the alignment of the module 2 held by the head 32 with the substrate 1 supported by the stage 31 based on the amount of deviation of the alignment marks M and m calculated by the calculation unit 83. Note that control by the movement control unit 84 may also be based on user commands input from, for example, the input device 91 described below.

The setting unit 85 is a processing unit that sets information in the memory unit 81 according to input. The input/output control unit 86 is an interface that controls signal conversion and input/output between each controlled unit.

An input device 91 and an output device 92 are connected to the control device 8. The input device 91 is an input means such as a switch, touch panel, keyboard, or mouse that allows the operator to operate the tiling device 3 via the control device 8. The operator can use the input device 91 to input various information to be set in the memory unit 81. The output device 92 is an output means such as a display, lamp, or meter that makes information for checking the status of the device visible to the operator. The output device 92 can also display an input screen for information from the input device 91.

[Effect]
Next, an example of the operation of this embodiment will be described with reference to FIGS. 4B, 5, and 7. FIG. 4B shows the state during pickup, and FIG. 5 shows the tiling procedure of this embodiment. FIG. 7 is a flowchart showing the tiling procedure of the tiling device 3. Although not shown, first, the module 2 is supported on the supply table S and carried into the housing C, and the substrate 1 is also supported on the stage 31 and carried into the housing C, and the supply table S and the stage 31 wait adjacent to each other (see FIG. 3). In addition, the head 32, the imaging unit 33, and the focal length adjustment unit 34 are supported by the linear motion mechanism 321 above the supply table S and wait facing the module 2 to be picked up this time, which is supported on the supply table S.

First, as shown in FIG. 4B (A), the movement control unit 84 controls the movement of the supply table S and the movement mechanism 320 so that the imaging unit 33 and the module 2 have a predetermined positional relationship. The predetermined positional relationship here refers to a positional relationship in which the imaging unit 33 can capture an image of the alignment mark m of the module 2 on the supply table S via the focal length adjustment unit 34. Next, the imaging control unit 82 causes the imaging unit 33 to capture an image of the alignment mark m of the module 2 to be picked up this time, which is supported on the supply table S, and transmits this captured image to the movement control unit 84. Since the alignment mark m of the module 2 placed on the supply table S is at the same height as the alignment mark M of the substrate 1 placed on the stage 31, when the imaging unit 33 captures an image of the alignment mark m of the module 2 on the supply table S, a clear, in-focus image can be obtained via the focal length adjustment unit 34. Based on this captured image, the movement control unit 84 calculates the position of the alignment mark m relative to the imaging unit 33 using known image processing, and controls the movement of the supply table S and the movement mechanism 320 so that a predetermined positional relationship is achieved. That is, the supply table S is moved in the Y direction and the head 32 is moved in the X direction, and the head 32 is aligned with a predetermined position relative to the module 2, i.e., the pickup position, as shown in Figure 5(A) (step S01).

Next, as shown in Figure 4B (B), the head 32 is moved in the Z direction toward the module 2, and the holding portion 32a of the head 32 is brought into contact with the upper surface of the module 2. Furthermore, a negative pressure is generated in the holding portion 32a of the head 32, and the module 2 is held by suction. As shown in Figure 4B (C), the head 32 is moved to a height where it can be moved above the substrate 1 while holding the module 2 by suction, thereby picking up the module 2 from the supply table S (step S02). Note that when picked up, the alignment mark m of the module 2 is held at a height where it can be imaged in focus by the imaging unit 33 without using the focal length adjustment unit 34.

Next, as shown in FIG. 5(B), the head 32 holding the module 2 by suction is moved in the X direction toward the position on the substrate 1 where the module 2 will be tiled, which is stored in the memory unit 81, and the stage 31 supporting the substrate 1 is moved in the Y direction. This transports the module 2 above the substrate 1 supported by the stage 31 (step S03). Here, in the example of FIG. 5, the position on the substrate 1 where the module 2 will be tiled this time is the upper right position on the substrate 1, then the upper left position, and then the lower left position. During this movement, the movement control unit 84 calculates the position of the alignment mark m on the module 2 that is shifted a predetermined amount in the XY plane relative to the alignment mark M on the substrate 1 where the module 2 will be tiled, in order to image the alignment mark M on the substrate 1 where the module 2 will be tiled and the alignment mark m on the module 2 within the same field of view. Then, the movement control unit 84 moves the module 2 and the substrate 1 relative to each other so that the alignment mark m is positioned at that position. In this case, the predetermined amount of deviation in position is an amount based on the field of view range of the imaging unit 33 such that the alignment mark M on the substrate 1 can be imaged by the imaging unit 33 without using the focal length adjustment unit 34, and the alignment mark m on the module 2 can be imaged by the imaging unit 33 via the focal length adjustment unit 34, within the same field of view of the imaging unit 33.

Then, the movement control unit 84 moves the head 32 to a height where the alignment marks M and m can be imaged within the same field of view. This height is the height where the focus of the imaging unit is aligned with the alignment mark m and, via the focal length adjustment unit 34, also aligned with the alignment mark M. This height is based on the pre-stored design value of the focal length. Then, under the control of the imaging control unit 82, the imaging unit 33 captures an image that includes the alignment mark m on the module 2 and the alignment mark M on the substrate 1 within the same field of view, and transmits this image to the calculation unit 83 and the movement control unit 84 (step S04). The imaging field of view of the imaging unit 33 at this time will be described with reference to Figure 8.

Figure 8 shows the imaging unit 33 capturing an image of alignment mark m on module 2 and alignment mark M on substrate 1. The imaging unit 33 is positioned so that both alignment marks m and M are captured within the same field of view. The module 2 is hatched in the figure. The area indicated by a circle in Figure 8 is the field of view. Alignment marks M and m are shown within the circle, i.e., within the same field of view. In this case, the outline of module 2 and alignment mark m are captured at the top of the figure, and the imaging unit 33 captures alignment mark m in the upper region of the figure. At the same time, alignment mark M is captured at the bottom of the figure, and the imaging unit 33 captures alignment mark M in the lower region of the figure.

Here, a focal length adjustment unit 34 made of a transparent material is located on the optical path from the imaging unit 33 to the alignment mark M. In other words, the focal length adjustment unit 34 is located in the lower area in Figure 8. This focal length adjustment unit 34 allows the imaging unit 33 to focus on the alignment mark M. That is, the imaging control unit 82 adjusts the focus of the imaging unit 33 to the alignment mark m of the module 2, and the focal length adjustment unit 34 also adjusts the focus to the alignment mark M of the substrate 1. This allows the imaging unit 33 to focus on and capture images of both alignment marks M and m, which are located at different distances.

Furthermore, in step S04, the elevation mechanism 322 may move the head 32 in the direction toward or away from the imaging unit 33 (Z direction), thereby adjusting the height position of the alignment mark m of the module 2 so that it is in focus with the imaging unit 33. The upper surface of the module 2 is held by the holding portion 32a. In other words, the alignment mark m of the module 2 and the holding portion 32a are held via the sealing member 23. Therefore, if there is variation in the thickness of the module 2 (as described above, the thickness of the sealing member 23 of the module 2 varies because it is formed by spreading a curable resin), there is a risk that the module 2 will not be in focus. In this case, by raising or lowering the height position of the head 32, the distance from the imaging unit 33 to the alignment mark m can be adjusted to accommodate the variation in the thickness of the sealing member 23. This focusing can be performed by the imaging unit 33 using a known method.

As mentioned above, the height of the head 32 is determined based on the design value of the focal length at which the imaging unit 33 focuses on the alignment mark m of the module 2. In other words, when imaging the alignment marks M and m, the alignment mark m of the module 2 is positioned at a predetermined distance (height) above the substrate 1. This distance allows for movement when aligning the module 2 with the tiling position of the substrate 1. This distance is the height (distance) of the module 2 from the substrate 1 and corresponds to the distance adjusted by the focal length adjustment unit 34. Therefore, when imaging the alignment marks M and m, this distance is the initial value, which is the Z-direction position (the distance between the module 2 and the substrate 1) and is constant. Therefore, the thickness of the focal length adjustment unit 34 is determined by this distance. In other words, the thickness of the focal length adjustment unit 34 is fixed. Unlike the sealing member 23 of the module 2, the thickness of the substrate 1 varies little and deviates little from the design value. Therefore, the focus of the imaging unit 33 on the alignment mark M on the substrate 1 via the focal length adjustment unit 34 does not deviate significantly, even if it is set based on the focal length with the alignment mark m of the module 2. Therefore, even if there is variation in the thickness of the module 2 and the module 2 cannot be focused at the design value, the alignment mark M on the substrate 1 is in focus, so the head 32 may control the module 2 to move up and down based on the thickness of the module 2 so that the focus is on the alignment mark m of the module 2. This makes it possible to respond to fluctuations in the position of the alignment mark m due to variations in the thickness of each module 2, and to more precisely focus on the alignment mark m.

After step S04, the calculation unit 83 detects the positions of the alignment marks M and m based on the captured image as shown in FIG. 8 and calculates the positional relationship between the alignment marks M and m (step S05). That is, the direction and amount of misalignment between the alignment marks M and m is calculated. In this embodiment, two imaging units 33 are provided. These two imaging units 33 can capture two captured images as shown in FIG. 8. The direction and amount of misalignment between the substrate 1 and the module 2 are calculated based on the captured images from two locations. The example shown in FIG. 9(A) shows a case where the orientation and position of the substrate 1 (the orientation in which the module 2 should be tiled) and the module 2 held by the head 32 do not match. The dotted circle indicates the imaging field of view. There are two imaging units 33, and each shows its own field of view range. The two imaging units 33 then capture images of the alignment marks M and m in their respective left and right field of view ranges. From the captured images of the left and right alignment marks M and m, the positional relationship (direction and amount of misalignment) between the left and right alignment marks M and m is calculated. Furthermore, the positional relationship (direction and amount of misalignment) between the left and right alignment marks M and between the left and right alignment marks m is calculated, and from these results, the angle between the line connecting the two alignment marks M and the line connecting the two alignment marks m is calculated. This angle is the angle between the substrate 1 and the module 2. From these calculation results, the positional relationship (direction and amount of misalignment) between the substrate 1 and the module 2 is determined. In other words, by calculating the direction and amount of misalignment in the alignment marks M and m based on the images captured by the two imaging units 33, misalignment in the XY and θ directions is corrected, enabling accurate tiling as shown in Figure 9(C).

Note that the example in Figure 9(A) shows an extreme directional deviation for ease of understanding. However, because module 2 is aligned with head 32 when picked up, it is unlikely that a directional deviation will occur that would result in the positional relationship between alignment mark M and alignment mark m being reversed, as shown in Figure 9(B). If module 2 were to shift while head 32 was moving, causing the positional relationship between alignment mark M and alignment mark m to be reversed, one of the two alignment marks M would be hidden by module 2, making it impossible to capture an image. In such a case, an error is detected and processing is halted. Furthermore, as explained in step 03, in order to capture alignment mark M and alignment mark m within the same field of view, module 2 is positioned such that alignment mark m is shifted a predetermined amount in the XY plane relative to alignment mark M. Therefore, reversing the positional relationship between alignment mark M and alignment mark m is avoided. However, there is a possibility that the alignment mark may fall outside the field of view, in which case one of the alignment marks cannot be imaged, and processing will also be halted as an error. Therefore, the directional misalignment between the substrate 1 and module 2 may be calculated from the difference in the amount of misalignment between the left and right alignment marks M and m (direction and amount of misalignment) rather than calculating the angle formed by the line connecting the two alignment marks M and m described above. In other words, the direction of misalignment (angle) may be calculated from the distance between the left and right alignment marks M and m. In this case, the calculation process can be simplified.

The calculation unit 83 then transmits the calculation results to the movement control unit 84, which, based on the calculation results, moves the stage 31 in the Y direction, the head 32 in the X direction, and the holder 32a in the θ direction, as shown in FIG. 5(C), to align the module 2 on the substrate 1 so that the alignment marks M and m overlap in a planar view (step S06). Finally, the movement control unit 84 moves (lowers) the head 32 toward the substrate 1, thereby tiling the module 2 on the substrate 1 (step S07). The head 32 then releases its suction hold of the module 2, moves (raises) away from the substrate 1, and then moves again in the X direction to move above the supply table S, specifically above the next module 2 to be suction-held, as shown in FIG. 5(D) (step S08). By repeating steps S01 to S08, the modules 2 are tiled on the substrate 1. Furthermore, when the supply table S becomes empty or when modules 2 have been tiled over the entire surface of the substrate 1, the movement control unit 84 moves the supply table S or stage 31 outside the housing C, and then returns to the inside of the housing C supporting new modules 2 or substrates 1. This allows for continuous tiling.

[effect]
(1) The tiling device 3 of this embodiment comprises a stage 31 that supports the substrate 1, a head 32 that transports a module 2 mounted with multiple elements to a position facing the substrate 1, an imaging unit 33 that faces the substrate 1 through the module 2 held by the head 32 and captures images of an alignment mark M provided on the substrate 1 and an alignment mark m provided on the module 2 within the same field of view, and a focal length adjustment unit 34 that is provided on the optical path connecting the alignment mark M and the imaging unit 33 and adjusts the focal length of the imaging unit 33 with respect to the alignment mark M so that the focus of the imaging unit 33 is simultaneously on the alignment marks M and m, and the head 32 tiled the module 2 on the substrate 1 based on the image captured by the imaging unit 33.

This allows module 2 to be tiled on substrate 1 based on captured images simultaneously focused on both alignment marks M and m, which are at different distances from the imaging unit, thereby enabling more accurate tiling than conventional methods. To tile module 2 on substrate 1, module 2 must move over substrate 1. Therefore, when module 2 is positioned facing the location on substrate 1 where module 2 will be tiled, a gap exists between substrate 1 and module 2. Therefore, the distance from imaging unit 33, which captures images of the alignment marks on substrate 1 and module 2, to module 2 is shorter than the distance to substrate 1. In other words, when module 2 is in focus, substrate 1 is out of focus. Similarly, when substrate 1 is in focus, module 2 is out of focus. Therefore, in the past, the alignment mark M on the substrate 1 and the alignment mark m on the module 2 were separately imaged using cameras (corresponding to the imaging unit 33 in this embodiment) focused on each of them, and the positional relationship between the substrate 1 and the module 2 was indirectly calculated from the positions of the alignment marks recognized from each image and the positional relationship between the two cameras. However, in this case, the position of the camera changes due to thermal expansion, vibrations occurring during imaging, and the like, making it difficult to perform high-precision alignment. Furthermore, when two additional cameras (imaging units 33) are used to recognize the positions of the alignment marks on the substrate 1 and the module 2 at two locations to align the orientations and positions of the substrate 1 and the module 2, and two separate images of the alignment marks on the substrate 1 and the module 2 are taken, it is difficult to perform high-precision alignment due to errors in the positional relationship between the two additional cameras caused by thermal expansion and vibrations occurring during imaging. Furthermore, using four cameras in this way inevitably makes the device configuration complex. On the other hand, the imaging unit 33 of this embodiment images the alignment mark M on the substrate 1 and the alignment mark m on the module 2 in the same field of view, so the relative positional relationship between the alignment marks M and m does not change even if vibrations or other issues occur during imaging. Also, instead of using four cameras as described above, only two imaging units 33 are required. This halves the error between the cameras, enabling highly accurate alignment and simplifying the device configuration.

(2) With the imaging unit 33 focused on the alignment mark M, the head 32 moves the module 2 in a direction toward or away from the imaging unit 33 depending on the thickness of the module 2 held by the head 32, and focuses the imaging unit 33 on the alignment mark m. This allows the alignment mark m of the module 2 to be focused more precisely. Furthermore, since it is easy to focus even if there is variation in the thickness of the substrate 1 or module 2, the module 2 can be tiled on the substrate 1 with high precision.

[Modification]
(1) In the above embodiment, the focal length adjustment unit 34 is supported by the linear motion mechanism 321 and moves in the X direction in conjunction with the head 32 and the imaging unit 33. However, this is not limited to this. For example, as shown in FIG. 10A , the focal length adjustment unit 34 may be integrally provided with the transparent portion 32b on the side surface of the holding portion 32a of the head 32. This simplifies the alignment of the focal length adjustment unit 34 with respect to the imaging unit 33. In particular, it is possible to easily adjust the position so that, for example, half of the field of view is covered by the focal length adjustment unit 34.

(2) Furthermore, as shown in FIG. 10(B), the focal length adjustment unit 34 may be provided in the imaging unit 33. In this way, similar to the above-described modified example, it is possible to easily align the focal length adjustment unit 34 with the imaging unit 33.

(3) Furthermore, as shown in FIG. 10(C), the focal length adjustment unit 34 may be provided directly on the head 32. In this case, the focal length adjustment unit 34 moves up and down as the head 32 moves up and down. However, if the imaging unit 33 is located on the optical path that images the alignment mark M, the focal point of the imaging unit 33 will be aligned with the alignment mark M, allowing for alignment. The placement and shape of the focal length adjustment unit 34 must be considered so that the focal length adjustment unit 34 does not intersect with the optical path that images the alignment mark m. For example, the focal length adjustment unit 34 shown in FIG. 10(C) has a hole (shown by a dotted line in the figure) on the optical path that images the alignment mark m, and the imaging unit 33 can image the alignment mark m through this hole. Therefore, when imaging the alignment mark m, the image can be captured in focus without going through the focal length adjustment unit 34.

(4) In the above embodiment, the imaging unit 33 is supported by the linear motion mechanism 321, but this is not limited to this. For example, it may be fixed to the housing C above the substrate 1. This makes it possible to avoid the effects of vibrations caused by the movement of the imaging unit 33 and vibrations generated in the tiling device 3, and reduces alignment errors. In this case, by configuring the stage 31 to be movable not only in the Y direction but also in the X direction, it is possible to move the alignment mark M on the substrate 1 directly below the imaging unit 33 provided on the housing C.

(5) In the above embodiment, two imaging units 33 are provided and capture images simultaneously. However, if the relative angular misalignment between the picked-up and held module 2 and the substrate 1 supported by the stage 31 is within an acceptable range, there is no need to align the θ (orientation) of the module 2 with respect to the substrate 1. In such a case, a single imaging unit 33 may be sufficient. This not only simplifies the device configuration, but also simplifies image processing and calculations for alignment, thereby shortening the tiling takt time and improving productivity. Furthermore, an optical system capable of observing multiple locations using mirrors or prisms can be applied to the optical system of the imaging unit 33 or an optical system external to the imaging unit 33, allowing two sets of alignment marks M and m to be captured at the same time. Even in this case, a single imaging unit 33 may be used. Furthermore, one imaging unit 33 may be moved to capture two sets of alignment marks M and m. Even in this case, information on the relative orientation of the substrate 1 and the module 2 can be obtained. In either case, the device configuration can be simplified and fewer parts are used, which reduces device costs and the occurrence of malfunctions. Furthermore, calibration work between the two imaging units 33 is no longer necessary, making device manufacturing and maintenance easier.

(6) In the above embodiment, the alignment mark M on the surface of the substrate 1 placed on the stage 31 and the alignment mark m on the surface of the module 2 placed on the supply table S were set to the same height, and when the imaging unit 33 images the alignment mark m on the surface of the module 2 placed on the supply table S, the alignment mark was imaged via the focal length adjustment unit 34. However, the pickup position can also be recognized if the height of the alignment mark m of the module 2 placed on the supply table S is set to the height when the module 2 is held by the head 32 and the alignment mark m and alignment mark M are imaged simultaneously. In this case, when imaging with the imaging unit 33, the alignment mark m is imaged directly in the field of view without using the focal length adjustment unit 34.

Other Embodiments
The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined.

1 Substrate 2 Module 21 Flexible substrate 22 Light-emitting element 23 Sealing member 3 Tiling device 31 Stage 32 Head 32a Holding portion 32b Transparent portion 320 Moving mechanism 321 Linear motion mechanism 322 Elevation mechanism 33 Imaging portion 34 Focal length adjustment portion 8 Control device 81 Memory portion 82 Imaging control portion 83 Calculation portion 84 Movement control portion 85 Setting portion 86 Input/output control portion 91 Input device 92 Output device C Housing M, m Alignment mark S Supply table

Claims (7)

a stage for supporting the substrate;
a head for transporting a module on which a plurality of elements are mounted to a position facing the substrate;
an imaging unit that faces the substrate through the module held by the head and images a first alignment mark provided on the substrate and a second alignment mark provided on the module within the same field of view;
a focal length adjustment unit that is provided on an optical path connecting the first alignment mark and the imaging unit, and that adjusts the focal length of the imaging unit with respect to the first alignment mark so that the imaging unit is focused on the first alignment mark and the second alignment mark simultaneously;
Equipped with
the head tiling the modules on the substrate based on the image captured by the imaging unit;
Tiling device. In a state where the imaging unit is focused on the first alignment mark via the focal length adjustment unit,
the head moves the module in a direction approaching or moving away from the imaging unit in accordance with a thickness of the module held by the head, and focuses the imaging unit on the second alignment mark;
The tiling device according to claim 1 . the focal length adjustment unit is supported by a linear motion mechanism,
The head and the imaging unit are provided to move in the X direction in conjunction with each other.
The tiling device according to claim 1. The focal length adjustment unit is provided on the head.
The tiling device according to claim 1. The focal length adjustment unit is provided on a holder of the head.
The tiling device according to claim 1. The focal length adjustment unit is provided in the imaging unit.
The tiling device according to claim 1. Two imaging units are provided,
two sets of the first alignment mark and the second alignment mark are provided;
each of the imaging units simultaneously captures an image of each pair of the first alignment mark and the second alignment mark within the same field of view;
7. A tiling device according to claim 1.