Kirigami-based design approach for fabricating large-scale electronic device arrays

Abstract

A manufacturing method and system based on paper-cut design are provided. The method includes providing a plurality of substrate units for mounting electronic devices in an initial state; providing at least one connector, the at least one connector connecting adjacent substrate units in the plurality of substrate units in an initial state, wherein the at least one connector includes one or more foldable areas defined by a plurality of creases and n stretchable layers stacked on each other; folding the one or more foldable areas of the connector by 180° along the plurality of creases; and flipping the n stretchable layers of the connector, and unfolding the n stretchable layers into a layer of a plane predetermined pattern connecting the plurality of substrate units. The manufacturing method and system unfold a small area of ​​thin film material into a large area network through a folding and unfolding process.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 257,126, filed on October 19, 2021, which is hereby incorporated by reference in its entirety (including any tables, figures, or drawings). Background Art

[0003] Electronic device arrays have a wide range of applications in different industrial fields. For example, in the field of human health monitoring, smart products such as smart cushions, smart insoles, and smart mattresses are often used to monitor human posture, heart rate, sitting, exercise, and lying time to provide health advice. To achieve these monitoring functions, sensor arrays are required. For example, in order to accurately detect a person's sitting posture, about ten pressure sensors need to be installed in the sitting area of ​​the smart cushion to monitor the pressure distribution in real time. For larger-sized smart mattresses and smart carpets, even more sensors are needed to achieve smart functions. In the field of structural health monitoring, large-scale sensor arrays are used to detect the location of structural damage, predict the remaining service time of the structure, or provide advice on the maintenance of mechanical structures to ensure safety. For example, when performing non-destructive testing on the surface of an aircraft, an ultrasonic sensor array can help quickly locate the location of damage and detect the extent of damage. For large facilities such as aircraft, bridges, or buildings, setting up vibration sensor arrays at key parts of the structure for long-term monitoring helps collect load history for estimated fatigue life to ensure facility safety. In addition, large-size electronic device arrays are often used for large display devices, such as display screens mounted on the exterior walls of buildings.

[0004] There are two ways to make arrays of electronic devices. The first is to use flexible printed circuit (FPC) technology to directly integrate electronic devices and circuits during the manufacturing process, which is a mature technology with a low failure rate. However, there are several problems with this method. First, the size of the array is limited by the maximum allowable area of ​​the production equipment. Second, the area of ​​the substrate material required for production is as large as the area of ​​the array, but the area used by the devices and wires is only a small part of the total area, and the rest of the area is wasted.

[0005] The second method is to connect all the electronic devices with wires after installing them independently. This method has great advantages for small arrays with a small number of devices. Each device can be maintained or replaced independently, the area of ​​the array and the position of the device can be easily changed by changing the length of the wire, and no special equipment is required for production and installation. However, for large-area dense arrays, this method greatly increases the difficulty of installation and the weight of the system, resulting in a high probability of failure caused by human error.

[0006] In addition, when the number of electronic devices increases, the number of connecting circuits or wires also increases accordingly. Since electronic devices are discrete components manufactured separately and an array network is formed by bonding, and the connecting circuit network provides physical connections between adjacent nodes where the electronic components are installed, the connecting circuit must cover a large area, and manufacturing such a network brings some challenges. For example, when wires or cables are used to connect electronic devices, the wiring pattern may be very complicated, resulting in poor reliability and increased cost, weight and installation work. One solution to these problems is to manufacture the connecting circuit network on a soft film to obtain high integration capability and high performance. However, due to the capacity limitations of existing manufacturing technology, the area covered by this method is limited, and most areas of the flexible circuit substrate cannot be used.

[0007] Therefore, there is a lack of methods to manufacture large-format electronic device arrays in an efficient and cost-effective manner. Summary of the invention

[0008] There remains a need in the art for improved designs and techniques for methods and systems for fabricating large scale electronic device arrays.

[0009] According to one embodiment of the present invention, a kirigami-enabled manufacturing method is provided. The method includes providing a plurality of substrate units for mounting electronic devices in an initial state; providing at least one connector, the at least one connector connecting adjacent substrate units in the plurality of substrate units in the initial state, wherein the at least one connector includes one or more foldable areas defined by a plurality of folds and n stretchable layers stacked on each other; folding the one or more foldable areas of the connector by 180° along the plurality of folds; and flipping the n stretchable layers of the connector and unfolding the n stretchable layers into a layer of a planar predetermined pattern connecting the plurality of substrate units, wherein n is an odd integer greater than or equal to 3. In addition, when the at least one connector includes a plurality of connectors, the method further includes orthogonally unfolding adjacent connectors to form a pattern of a k*k matrix of substrate units, wherein k is an integer greater than or equal to 2. When the lengths of the plurality of connectors in the initial state are the same, the shape of the pattern of the k*k matrix of the substrate unit formed after unfolding is a rectangle. On the other hand, when the lengths of the plurality of connectors in the initial state are different, the pattern of the k*k matrix of the substrate unit formed after unfolding has a three-dimensional (3D) structure. The plurality of substrate units are made of a flexible circuit substrate.

[0010] In certain embodiments of the present invention, a manufacturing system is provided, comprising: a plurality of substrate supports, each substrate support is connected to a unit of a foldable substrate pattern; a plurality of slide rails arranged in a row direction and a column direction; a support structure; and a motor, each substrate support is connected to a first corresponding slide rail in a row direction and to a second corresponding slide rail in a column direction, and the slide rails are driven by the motor. In addition, the plurality of slide rails are configured to synchronize the movement of the unit of the foldable substrate pattern in a row direction or a column direction to flip the foldable substrate pattern and unfold the foldable substrate pattern into a planar substrate pattern of a larger size.

[0011] In some embodiments of the present invention, a manufacturing system based on paper-cut design is provided, including a substrate having a plurality of substrate units for mounting electronic devices and at least one connector connecting adjacent substrate units in the plurality of substrate units, wherein the at least one connector includes one or more foldable areas defined by a plurality of creases and n stretchable layers stacked on each other; a release tape; a base mold; a pushing mold; and a pushing film. In addition, the top and bottom surfaces of the release tape have adhesive to attach the substrate to the base mold. The area on the release tape corresponding to the foldable area of ​​the substrate is hollowed out. The base mold is made of metal or other rigid materials to support the substrate. The area on the base mold corresponding to the foldable area of ​​the substrate is hollowed out. In addition, the pushing mold is made of rigid material. The pushing mold is configured to install a pushing film at a position configured to correspond to the foldable area of ​​the substrate. The pushing film is made of plastic or other elastic materials.

[0012] In another embodiment of the present invention, a manufacturing method based on paper-cut design is provided, including providing a substrate having a plurality of substrate units for mounting electronic devices and at least one connector connecting adjacent substrate units in the plurality of substrate units, wherein the at least one connector includes one or more foldable areas and n stretchable layers stacked on each other; attaching a release tape to a base mold; transferring the substrate to the base mold; applying adhesive to the overlapping areas after folding; pushing up one or more foldable areas; folding one or more foldable areas with a rolling device; pressing one or more foldable areas and waiting for the adhesive to solidify; rotating the base mold and the substrate by 90 degrees, and repeating the folding process for the substrate in other folding directions; and releasing the folded substrate from the base mold. In addition, a manufacturing method includes the steps of the above-mentioned manufacturing method based on paper-cut design, and also includes the steps of attaching an array of electronic devices to the substrate, and covering the array of electronic devices and the substrate with a conformal material to protect the circuits of the array of electronic devices and the substrate. The array of electronic devices is attached to the substrate by welding or bonding. The conformal material is one of a plastic film, a silicone and a fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1is a schematic diagram of a single connector pattern according to one embodiment of the present invention.

[0014] Figure 2 is a schematic diagram of a folding and unfolding process of a single connector pattern according to an embodiment of the present invention.

[0015] Figure 3 is a schematic diagram of an isometric view of a folding and unfolding process according to one embodiment of the present invention.

[0016] Figure 4 Schematic diagram of a first embodiment of a folding and unfolding process of a 2*2 electronic device array according to an embodiment of the present invention.

[0017] Figure 5 It is a schematic diagram of a second embodiment of a 2*2 electronic device array with a larger expansion rate and a higher area utilization rate according to an embodiment of the present invention.

[0018] Figure 6 is a schematic diagram of a 4*4 array using a high efficiency design according to an embodiment of the present invention.

[0019] Figure 7 FIG. 1 is a schematic diagram of a flexible circuit substrate designed for a three-dimensional (3D) hemispherical curved surface pattern in its initial state according to an embodiment of the present invention.

[0020] Figure 8 is a schematic diagram of a folded and unfolded three-dimensional hemispherical curved surface pattern according to an embodiment of the present invention.

[0021] Fig. 9 Schematic diagram of a mold and tool for folding a 3*3 electronic device array according to an embodiment of the present invention.

[0022] Fig.10 Schematic diagram of a deployment system for a 3*3 array of electronic devices according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] Embodiments of the present invention relate to a method and system for manufacturing large-scale electronic device arrays based on kirigami design.

[0024] The terms used herein are only used to describe specific embodiments and are not intended to limit the present invention. As used herein, the term "and / or" includes any and all combinations of one or more related listed items. As used herein, the singular forms "a, an" and "the" are intended to include plural forms as well as singular forms, unless the context clearly indicates otherwise. It can also be understood that when used in this specification, the term "comprises and / or comprising" specifically describes the presence of the features, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof.

[0025] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. It should also be understood that terms such as those defined in commonly used dictionaries should be interpreted to have the same meaning as in the context of the relevant technology and the present disclosure, and will not be interpreted as idealized or overly formal meanings unless explicitly defined herein.

[0026] When the term "about" is used in conjunction with a numerical value, it can be understood that the value can be within the range of 90% to 110% of the value, that is, the value can be + / -10% of the value. For example, "about 1 kg" means from 0.90 kg to 1.1 kg.

[0027] In describing the present invention, it is understood that a number of techniques and steps are disclosed. Each of these techniques and steps has its own advantages, and each can be used in combination with one or more (or in some cases, all) of the other disclosed techniques. Therefore, for the sake of clarity, this description will avoid unnecessary repetition of every possible combination of the various steps. However, when reading the specification and claims, it should be understood that such combinations are fully within the scope of the present invention and the claims.

[0028] In an embodiment of the present invention, dense circuits and devices are first manufactured on a small area of ​​a substrate, and then the small area substrate is unfolded into a large area array of electronic devices through folding and unfolding steps to achieve planar or curved configurations with various sizes and device densities.

[0029] In one embodiment of the present invention, the manufacturing method based on the paper-cut design includes the following steps: substrate manufacturing, device installation (which may also be performed after the folding and unfolding steps), folding and unfolding, and packaging (which may be omitted depending on the specific application scenario). Each step will be explained in more detail below.

[0030] Substrate Manufacturing: Flexible circuit substrates with design patterns based on paper-cut designs can be manufactured by flexible printed circuit (FPC) processing technology or other suitable thin film manufacturing processes.

[0031] Device Mounting: Electronic devices are mounted on flexible circuit substrates by methods including, but not limited to, soldering and bonding.

[0032] Folding and unfolding: Flexible circuit substrates are folded and unfolded with the help of customized molds and tools to obtain large-scale electronic device arrays.

[0033] Packaging: The flexible circuit substrate is covered with a conformal material (such as plastic film, silicone or fabric) to protect the circuits and devices of the flexible circuit substrate.

[0034] The following are examples that illustrate the process of implementing the present invention. These examples should not be construed as limiting.

[0035] Manufacturing method based on paper-cut design

[0036] Substrate manufacturing

[0037] First, a flexible circuit substrate with a circuit is made, and then the electronic device is mounted on the flexible circuit substrate. The flexible circuit substrate includes a substrate unit ("island") for mounting the electronic device and a connector for carrying the connecting wires. Adjacent islands are connected by connectors, where the folding and unfolding deformation of the substrate is performed. Each connector includes one or more foldable areas defined by a plurality of creases and a plurality of stretchable layers stacked on each other. It should be noted that the number of layers of the connector must be an odd number.

[0038] refer to Figure 1 The simplest substrate pattern unit 100 of a pattern based on a paper-cut design includes two substrate units ("islands") 110 connected by a connector 120. The substrate pattern unit 100 is defined by three key parameters: the connector length l0 in the initial state, the width w of the connector, and the side length a of the island.

[0039] In certain embodiments, the flexible circuit substrate may be made of a film material, such as polyimide (PI), polyethylene terephthalate (PET), parylene-C, or paper.

[0040] In one embodiment, each island is square in shape.

[0041] In other embodiments, the islands are rectangular in shape or any other suitable shape.

[0042] Substrate elongation

[0043] refer to Figure 2 and Figure 3The stretching process is divided into two steps. The first step is to fold one or more folding areas 180 degrees, and the second step is to stretch multiple stretchable layers of the flexible circuit substrate into a layer of a planar predetermined pattern connecting multiple substrate units.

[0044] By varying the length and width of the connector, different elongation rates can be achieved. For example, Figure 2 The connector in has three stretchable layers. To obtain a longer elongation, the connector can have five, seven, or other layers. It should be noted that the number of layers of the connector must be an odd number.

[0045] Two-dimensional (2D) unfolding of substrate

[0046] In one embodiment of the present invention, a one-dimensional (1D) elongation process can be easily converted into a two-dimensional (2D) expansion process by expanding the connector orthogonally. Figure 4 Shows the Figure 3 The pattern is orthogonally expanded into a 2*2 matrix of electronic device arrays.

[0047] It can be seen that in Figure 4 During the two-dimensional expansion process, the area in the middle of the pattern cannot be expanded and is therefore wasted.

[0048] In one embodiment, Figure 5 As shown, a flexible substrate pattern is provided to reduce wasted area.

[0049] In arrays with more islands, the advantages of this design are much greater. On the one hand, the wasted area is reduced. On the other hand, the unfolding ratio of the flexible circuit substrate is increased. Figure 6 A 4*4 electronic device array based on an efficient flexible substrate pattern is shown.

[0050] Three-dimensional structure of substrate

[0051] As described above, each island is connected to its adjacent island by a connector, and each connector can be designed independently. The length of the connector determines the length of the rows and columns of the electronic device array, and the length of the rows and columns determines the shape of the entire electronic device array. If the length of all rows is the same and the length of all columns is the same, the electronic device array is formed into a rectangular shape. On the other hand, if the length of the rows is different or the length of the columns is different, a three-dimensional (3D) structure of the flexible circuit substrate can be constructed.

[0052] In one embodiment, Figure 7 The flexible circuit substrate designed for a three-dimensional hemispherical curved surface pattern is shown in an initial state (ie, before being folded and unfolded). Figure 7The gap shown in is configured to control the length of the connector. The length of the gap is configured to allow the connector to have different lengths after the flexible circuit substrate is unfolded. In turn, the length of the connector between the islands controls the shape of the three-dimensional hemispherical curved surface pattern after unfolding.

[0053] Next, Figure 7 The two-dimensional thin film flexible circuit substrate is converted into Figure 8 A three-dimensional hemispherical curved surface pattern with a curved surface network is shown.

[0054] Folding tools

[0055] Flexible circuit substrates can be folded using custom molds and tools. Fig. 9 As shown, the following dies and tools for folding are provided.

[0056] A release tape 710 having adhesive on both sides is provided to fix the flexible circuit substrate 700 on the base mold 720. An area on the tape corresponding to the folding area of ​​the flexible circuit substrate 700 is hollowed out.

[0057] The base mold 720 is made of metal or other rigid materials to support the flexible circuit substrate 700. In the same manner, a region of the base mold 720 corresponding to the folding region of the flexible circuit substrate 700 is hollowed out.

[0058] The push mold 730 is made of a rigid material, and the pushing film 740 is made of plastic or other elastic materials. The push mold 730 is used to install the pushing film 740 , and the position of the pushing film 740 is included in the folding area of ​​the flexible circuit substrate 700 .

[0059] With the help of the folding tool, perform the following steps of the folding process:

[0060] Use blue tape to pick up the independent flexible circuit substrate.

[0061] Attach the release tape to the base mold,

[0062] Transfer the flexible circuit substrate from the blue ribbon to the base mold,

[0063] Apply glue to the overlapping areas after folding.

[0064] Push up the folding area.

[0065] folding the folded area with a roller,

[0066] Press the folded area and wait for the glue to cure completely.

[0067] Because folding in 4 directions is required, the base mold and the flexible circuit substrate are rotated 90 degrees and the folding process is repeated three times, and

[0068] The flexible circuit substrate is released from the mold by hot air or ultraviolet (UV) light.

[0069] Expand Tool

[0070] The unfolding step is to synchronize the movement of the islands in each row and column of the electronic device array. This task can be performed by Fig.10 The multi-slide system shown in FIG. 1 is used to complete the process. Each island of the flexible circuit substrate is connected to a bracket, and each bracket is simultaneously connected to the corresponding slide rails in the row and column, and each slide rail is driven by a motor. Therefore, the synchronous movement of each row and column can be achieved, and the flexible circuit substrate can be evenly spread out.

[0071] Electronic device installation

[0072] Depending on the application, the electronic components can be mounted on the flexible circuit substrate before or after the folding and unfolding process. The electronic components can be mounted on the flexible circuit substrate by welding, bonding or any other suitable method. The connection pads can be made directly on the islands of the flexible circuit substrate.

[0073] Encapsulation

[0074] After the steps of folding, unfolding and installing the electronic devices are performed, the electronic device array can be covered with a conformal material to protect the circuits and electronic devices. Since the electronic device array has good flexibility but poor stretchability, PET, PI or any other suitable plastic film can be used to encapsulate the electronic device array.

[0075] In an embodiment of the present invention, a large-scale electronic device array is manufactured based on a paper-cut pattern design to improve production efficiency and reduce production costs, thereby achieving low-cost manufacturing, and is capable of manufacturing a large-scale sensor or display array with various sensors or light-emitting elements.

[0076] The embodiments of the present invention have two advantages. First, the material required to make an array of the same area is greatly reduced, thereby improving the utilization rate of the material and greatly reducing the cost of large-scale production. Second, a small area of ​​thin film material can be unfolded by a smaller machine to make a large area array, thereby improving the production capacity of the machine for manufacturing electronic device arrays.

[0077] All patents, patent applications, provisional applications, and publications referenced or cited herein are hereby incorporated by reference in their entirety, including all figures and tables, to the extent they are consistent with the explicit teachings of this specification.

[0078] It should be understood that the examples and embodiments described herein are for illustrative purposes only, and that those skilled in the art will recognize various modifications or changes therefrom, and that these modifications or changes will be included within the spirit and scope of the present application and within the scope of the appended claims. In addition, any element or limitation of any invention or embodiment thereof disclosed herein may be combined with any and / or all other elements or limitations disclosed herein (alone or in any combination) or any other invention or embodiment thereof, and all such combinations are considered within the scope of the present invention without limitation thereto.

Claims

1. A manufacturing method based on paper-cut design, comprising: providing a plurality of substrate units for mounting electronic components in an initial state; providing at least one connector, the at least one connector connecting adjacent substrate units among the plurality of substrate units in the initial state, wherein the at least one connector comprises one or more foldable regions defined by a plurality of folds and n stretchable layers stacked on each other; folding the one or more foldable regions of the connector 180° along the plurality of folds; and The n stretchable layers of the connector are turned over, and the n stretchable layers are unfolded into a layer of a planar predetermined pattern connecting the plurality of substrate units.

2. The manufacturing method according to claim 1, wherein: n is an odd integer greater than or equal to 3.

3. The manufacturing method according to claim 1, when the at least one connector includes a plurality of connectors, the manufacturing method further comprises: Adjacent connectors are orthogonally deployed to form a k*k matrix pattern of the plurality of substrate units, where k is an integer greater than or equal to 2.

4. The manufacturing method according to claim 3, wherein: When the lengths of the plurality of connectors in the initial state are the same, the shape of the pattern of the k*k matrix of the plurality of substrate units formed after being unfolded is a rectangle.

5. The manufacturing method according to claim 3, wherein: When the lengths of the plurality of connectors in the initial state are different, a pattern of a k*k matrix of the plurality of substrate units formed after development has a three-dimensional (3D) structure.

6. The manufacturing method according to claim 1, wherein: The plurality of substrate units are made of a flexible circuit substrate.

7. A manufacturing system for the manufacturing method according to claim 1, comprising: a plurality of substrate supports respectively connected to the plurality of substrate units of the foldable substrate pattern; A plurality of slide rails are arranged in row and column directions; Support structure; as well as Motor; Each substrate support is connected to a first corresponding slide rail in the row direction and to a second corresponding slide rail in the column direction, and the slide rails are driven by the motor.

8. The manufacturing system according to claim 7, wherein: The plurality of slide rails are configured to synchronize the movements of the plurality of substrate units of the foldable substrate pattern in the row direction or the column direction to flip the foldable substrate pattern and unfold the foldable substrate pattern into a planar substrate pattern of a larger size.

9. A manufacturing system based on paper-cut design, comprising: A substrate having a plurality of substrate units for mounting electronic devices and at least one connector connecting adjacent substrate units among the plurality of substrate units, wherein the at least one connector comprises one or more foldable regions defined by a plurality of creases and n stretchable layers stacked on each other; Release strap; Schema; Push mold; and Push the film.

10. The manufacturing system according to claim 9, wherein: The release tape has adhesive on the top and bottom surfaces to attach the substrate to the base mold.

11. The manufacturing system according to claim 9, wherein: An area on the release tape corresponding to the foldable area of ​​the substrate is hollowed out.

12. The manufacturing system according to claim 9, wherein: The base mold includes metal or other rigid material to support the substrate.

13. The manufacturing system according to claim 9, wherein: An area on the base mold corresponding to the foldable area of ​​the substrate is hollowed out.

14. The manufacturing system according to claim 9, wherein: The push die is made of rigid material.

15. The manufacturing system according to claim 9, wherein: The push mold is configured to mount the push sheet at a position configured to correspond to the one or more foldable regions of the base plate.

16. The manufacturing system according to claim 9, wherein: The push piece is made of plastic or other elastic materials.

17. A manufacturing method based on paper-cut design, comprising: Providing a substrate having a plurality of substrate units for mounting electronic devices and at least one connector connecting adjacent substrate units among the plurality of substrate units, wherein the at least one connector comprises one or more foldable regions and n stretchable layers stacked on each other; attaching a release strip to the base mold; transferring the substrate to the base mold; applying adhesive to the folded overlapping areas; Pushing up the one or more foldable regions; folding the one or more foldable regions using a rolling device; pressing the one or more foldable regions and waiting for the adhesive to cure; Rotating the base mold and the substrate by 90 degrees and repeating the folding process on the substrate for other folding directions; and The folded substrate is released from the base mold.

18. A manufacturing method comprising: Execute the steps of the manufacturing method based on paper-cut design according to claim 17; attaching an array of electronic devices to the substrate; as well as The electronic device array and the substrate are covered with a conformal material to protect the electronic device array and circuits of the substrate.

19. The manufacturing method according to claim 18, wherein: The electronic device array is attached to the substrate by soldering or bonding.

20. The manufacturing method according to claim 18, wherein: The conformal material is one of a plastic film, silicone and fabric.

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