Flexible stretchable packaging structure and phototherapy patch

Abstract

The invention discloses a flexible stretchable packaging structure and a phototherapy patch, and relates to the technical field of flexible stretchable electronics. The packaging structure comprises a stretchable substrate; the elastic conductive circuit is arranged on the stretchable substrate and comprises a first wire, a second wire and a bonding pad which are connected with one another; the stretchable package is arranged on the stretchable substrate, covers the first wire and is provided with a bonding pad for exposing the elastic conductive circuit and a window for exposing the second wire; the electronic device is arranged on the bonding pad; the tensile packaging at the joint of the electronic device and the bonding pad is reinforced, the second wire in the open window is covered, and the part around the open window can be subjected to tensile packaging; a portion of the first wire is vertically opposite to a portion of the tensile package across the tensile package. The stretchable conductive structure is formed by the stretchable substrate, the elastic conductive circuit and the stretchable package, connection and reinforcement between the LED lamp beads and the elastic conductive circuit are completed through the stretch-resistant package, and the risk of tensile fracture between the LED lamp beads and the elastic conductive circuit is reduced.

Description

Technical Field

[0001] This invention belongs to the field of flexible and stretchable electronic technology, and particularly relates to a flexible and stretchable packaging structure and a phototherapy patch. Background Technology

[0002] Phototherapy skin patches are products that use light for skin care and beauty. Depending on the area targeted, various phototherapy products have been developed on the market, such as phototherapy face masks, phototherapy eye patches, and other phototherapy products for different areas. In recent years, to improve the user experience, many manufacturers have launched their own flexible phototherapy products. The vast majority of these are FPC (flexible printed circuit board) products based on PI (polyimide) film, thus meeting users' needs for flexibility and bendability. At the same time, to improve the skin-friendliness of FPC flexible circuit boards, skin-friendly materials such as TPU are used for surface encapsulation, further enhancing the user's wearing experience.

[0003] With the continuous development of technological life, simple flexible phototherapy skin patches are no longer sufficient to meet the ever-increasing user demands. Products also need to have a certain degree of stretchability to meet users' requirements for appropriate stretching and deformation performance. However, the structure and performance stability and reliability of flexible stretchable electronics currently on the market are not good, which makes it difficult for phototherapy products to be further optimized in this direction. Summary of the Invention

[0004] In view of this, one object of the present invention is to provide a flexible and stretchable packaging structure to solve the problem of poor reliability of flexible and stretchable electronics in the prior art.

[0005] In some illustrative embodiments, the flexible stretchable package structure includes: a stretchable substrate; elastic conductive lines disposed on the stretchable substrate, including a first trace, a second trace, and pads connected in sequence; a stretchable package disposed on the stretchable substrate, covering the first trace of the elastic conductive lines, and having an opening thereon for exposing the pads and the second trace of the elastic conductive lines; an electronic device disposed on the pads within the opening; a tensile-resistant package reinforcing the connection between the electronic device and the pads, which simultaneously covers the second trace within the opening and a portion of the stretchable package surrounding the opening; a portion of the first trace is vertically opposite to a portion of the tensile-resistant package across the stretchable package.

[0006] In some alternative embodiments, the height of the electronic device is greater than the height of the stretchable package.

[0007] In some alternative embodiments, the tensile-resistant encapsulation is formed by dispensing to create an arcuate structure that also covers the electronic device.

[0008] In some alternative embodiments, the top surface of the tensile package is a planar structure parallel to the top surface of the electronic device.

[0009] In some alternative embodiments, the pads are interconnected with the electronic device via conductive adhesive or solder.

[0010] In some alternative embodiments, the stretchable substrate and / or the stretchable package may be made of TPU, TPE, PDMS or silicone.

[0011] In some alternative embodiments, an adhesive layer is further provided between the electronic device and the stretchable substrate.

[0012] In some alternative embodiments, the length of the contact surface between the first trace and the second trace is not less than 1 / 3 of the perimeter of the combined pattern of the second trace and the pad, and the contact surface between the first trace and the second trace has at least one inflection point.

[0013] In some alternative embodiments, the tensile-resistant encapsulation layer is a non-stretchable structure.

[0014] In some alternative embodiments, the elastic conductive layer is formed by printing with a low-temperature conductive paste, and its elongation at break is not less than 50%.

[0015] Another objective of this invention is to provide a phototherapy patch to address the problems in the prior art.

[0016] In some illustrative embodiments, the phototherapy patch includes: the flexible stretchable encapsulation structure described in any of the preceding embodiments.

[0017] Compared with the prior art, this application has the following advantages:

[0018] This application utilizes a stretchable substrate, elastic conductive lines, and a stretchable package to form a stretchable conductive structure. Then, an anti-stretch package reinforces the connection between the LED chip and the elastic conductive lines, reducing the risk of tensile breakage between the LED chip and the elastic conductive lines. Furthermore, part of the anti-stretch package directly acts on the second trace, while part acts on a portion of the first trace through the stretchable package. Therefore, along the direction of the pads of the elastic conductive lines, the second trace, a portion of the first trace affected by the anti-stretch package, and another portion of the first trace unaffected by the anti-stretch package, a structure with a gradually increasing stretchability gradient is achieved. This effectively reduces the significant change in stretchability between the non-stretchable and stretchable structures, further improving the overall protection against tensile breakage of the phototherapy patch. Moreover, the anti-stretch package not only reinforces the connection between the LED chip and the pads but also covers the second trace and the area around the window of the stretchable package, expanding the multiple bonding surfaces of varying heights within the anti-stretch package and further enhancing its adhesion and protection range. Attached Figure Description

[0019] Figure 1 This is a structural example of the flexible and stretchable packaging structure in the embodiments of the present invention;

[0020] Figure 2 This is a second example of the flexible and stretchable packaging structure in the embodiments of the present invention;

[0021] Figure 3 This is a process example one of the flexible and stretchable packaging structures in the embodiments of the present invention;

[0022] Figure 4 This is a second example of the process steps for the flexible and stretchable packaging structure in this embodiment of the invention;

[0023] Figure 5 This is Example 3 of the process steps for the flexible and stretchable packaging structure in this embodiment of the invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that, where there is no conflict, the various technical features in the embodiments of the present invention can be combined with each other.

[0026] This invention discloses a flexible and stretchable packaging structure, specifically, as shown in the embodiments of the present invention. Figure 1-5 As shown, Figure 1 This is a structural example of the flexible and stretchable packaging structure in the embodiments of the present invention; Figure 2 This is a structural example of the flexible and stretchable packaging structure in the embodiments of the present invention; Figure 3 This is a process example one of the flexible and stretchable packaging structures in the embodiments of the present invention; Figure 4 This is a second example of the process steps for the flexible and stretchable packaging structure in this embodiment of the invention; Figure 5 This is a third example of the process steps of the flexible stretchable packaging structure in this embodiment of the invention. The flexible stretchable packaging structure includes: a stretchable substrate 10; an elastic conductive line 20 disposed on the stretchable substrate 10, including a first trace 21, a second trace 22, and a pad 23 connected in sequence; a stretchable package 30 disposed on the stretchable substrate 10, covering the first trace 21 of the elastic conductive line 20, and having an opening 40 thereon for exposing the pad 23 and the second trace 22 of the elastic conductive line 10; an electronic device 50 disposed on the pad 23 within the opening 40; a tensile-resistant package 60 reinforcing the connection between the electronic device 50 and the pad 23, which simultaneously covers the second trace 22 within the opening 40 and a portion of the stretchable package 30 surrounding the opening 40; a portion of the first trace 21 is vertically opposite to a portion of the tensile-resistant package 60 across the stretchable package 30.

[0027] This application utilizes a stretchable substrate, elastic conductive lines, and a stretchable package to form a stretchable conductive structure. Then, it reinforces the connection between the electronic device and the elastic conductive lines through tensile-resistant packaging, thereby reducing the risk of tensile breakage between the electronic device and the elastic conductive lines.

[0028] Secondly, the tensile package not only reinforces the connection between electronic components and pads, but also covers the second trace and the stretchable package around the window, expanding the multiple mating surfaces of the tensile package at different heights, further improving the adhesion and protection range of the tensile package.

[0029] Furthermore, when a product is subjected to external stretching, the tensile stress points of such a product combining stretchable and non-stretchable structures are not evenly distributed across the stretchable structure as in a purely stretchable structure. Instead, they are mainly concentrated at the interface between the stretchable and non-stretchable structures. Therefore, the better the stretchability of the stretchable structure, the more likely it is to experience overstretching at the interface, leading to the risk of open circuits in the conductive circuit. In this application, since part of the tensile-resistant package acts directly on the second trace, and part of the tensile-resistant package acts on part of the first trace through the stretchable package, a structure with a gradient change (gradually increasing) in stretchability is achieved along the direction of the pads of the elastic conductive circuit (directly affected by the non-stretchability of the electronic device), the second trace (directly affected by the tensile resistance of the tensile-resistant package), a part of the first trace affected by the tensile-resistant package (indirectly affected by the tensile resistance of the tensile-resistant package through the stretchable package), and another part of the first trace not affected by the tensile-resistant package (not affected by the electronic device and the tensile-resistant package). This effectively reduces the significant change in stretchability between the non-stretchable and stretchable structures, further improving the overall tensile resistance of the product against open circuits.

[0030] The stretchable substrate and / or stretchable package in the embodiments of the present invention include, but are not limited to, stretchable materials such as TPU, TPE, PDMS, and silicone.

[0031] The elastic conductive circuit in this embodiment of the invention can be formed by printing an elastic conductive paste (also known as a stretchable conductive paste). The elastic conductive paste in this embodiment of the invention is a low-temperature conductive paste with resin as the binder phase, mainly including: conductive filler, resin and solvent. The resin system contains elastic resin components, which gives it elastic and stretchable properties. The main structure of the elastic conductive printed circuit formed after the elastic conductive paste is printed and cured is conductive particles and resin film that binds the conductive particles.

[0032] The elastic resin contained in the resin system in the embodiments of the present invention is not limited to one or more of silicone resin, TPU resin, SEBS resin, and SIS resin.

[0033] Those skilled in the art should note that although the elastic conductive paste referred to in this application is a low-temperature conductive paste, it is different from traditional low-temperature conductive pastes. Although it is also composed of conductive particles and resin film-forming material that binds the conductive particles after curing, its resin system contains almost no elastic properties or has low elastic properties, which makes the entire structure after curing brittle. Under repeated bending, it is more prone to circuit breakage and peeling.

[0034] Since the elastic properties of the elastic conductive paste depend on its overall material system, such as specific components, component ratios, and preparation processes, and the material system is too complex, this invention does not limit the elastic conductive paste, but specifically defines the elastic conductive circuit. Specifically, the elastic conductive circuit in the embodiments of this invention can be a conductive printed circuit formed by a low-temperature conductive paste and with an elongation at break of not less than 50%. If the elongation at break of not less than 50%, the problem of poor conductivity during stretching is likely to occur.

[0035] In this embodiment of the invention, the elongation at break refers to the maximum degree of stretching of the elastic conductor (such as the elastic conductive circuit in this application) while maintaining its conductivity (circuit continuity). Specifically, the elongation at break of the elastic conductive circuit in this embodiment of the invention is measured using an elastic conductive printed circuit that is 5000 μm wide and 10 μm thick. Therefore, when measuring the elongation at break of an elastic conductive printed circuit, those skilled in the art should require that the cross-sectional area (perpendicular to the stretching direction) of the elastic circuit be no less than 5 × 10⁻⁶. 4 μm 2 Alternatively, the dimensions can be used to estimate the value.

[0036] For example, a 10cm long, 5000μm wide, and 10μm thick elastic conductive line is stretched along its length to 15cm, reaching a stretch of 50%. At this point, the elastic line still maintains its conductivity, meaning that the elongation at the power outage of the elastic conductive line is at least 50%.

[0037] The tensile properties of the tensile-resistant package in this embodiment of the invention are lower than those of the stretchable package. Specifically, the tensile modulus of the tensile-resistant package should be greater than the tensile modulus of the stretchable substrate, the stretchable package, and the elastic conductive line. Further, the tensile modulus of the tensile-resistant package is at least 10 times that of the stretchable substrate and the stretchable package. Further, the tensile-resistant package in this embodiment of the invention can be a non-stretchable structure. Wherein, when the tensile-resistant package can be a non-stretchable structure, the tensile-resistant package and the electronic device can be considered to be equally non-stretchable, and in this case, the aforementioned second trace, part of the first trace, and another part of the first trace still maintain a gradient change in stretchable properties.

[0038] In some embodiments of the invention, the height of the electronic device is greater than the height of the stretchable package. This embodiment reduces the overall thickness requirement of the stretchable package, which is beneficial for reducing the average thickness of the product, further improving the stretchability of the product, reducing material usage, and enhancing the user experience in terms of wearability, portability, and rollability.

[0039] In some embodiments, the tensile-resistant encapsulation of the present invention can be formed by dispensing to create an arc structure, which also covers the electronic device. The tensile-resistant encapsulation can use UV encapsulating adhesive; additionally, the dispensing process typically causes the adhesive to form an arc structure under the influence of gravity and surface tension. This arc structure is not only arc-shaped in its vertical projection onto the substrate, but also arc-shaped in its vertical direction. In other embodiments, the tensile-resistant encapsulation of the present invention can also be other structures besides arc structures, as long as the above requirements are met.

[0040] Furthermore, the tensile-resistant encapsulation in this embodiment of the invention can also cover electronic devices, which not only reinforces the electronic devices, but also prevents electronic devices with sharp edges or temperature changes (such as heating) from coming into contact with the user's skin for some wearable products, thereby further improving the user's wearing experience.

[0041] The electronic devices in this invention include, but are not limited to, LED beads (including MiniLED, OLED, microLED, etc.), chips (also known as integrated circuits), resistors, inductors, capacitors, and other electronic components. Preferably, LED beads can be used as electronic devices, thereby creating flexible and stretchable phototherapy patch products. The phototherapy patch can be applied to various areas, including but not limited to the face, eyes, chin, torso, hands, and legs, and can be designed to fit different areas. Specifically, the phototherapy patch may include: phototherapy facial masks, phototherapy eye patches, etc.

[0042] In some embodiments of the present invention, the top surface of the tensile-resistant package is a planar structure parallel to the top surface of the electronic device. This planar top surface structure of the tensile-resistant package is primarily used in phototherapy patch products where the electronic device is an LED chip. The emitting surface of the LED chip faces upwards (i.e., the top surface of the tensile-resistant package). Designing the top surface of the tensile-resistant package as a planar structure reduces the optical path difference between various points on the top surface of the package, which helps improve the consistency of optical diffusion provided by the package and reduces the difference in irradiation of the skin by the LED chip. When the electronic device is an LED chip, the tensile-resistant package should be made of a transparent or light-transmitting material.

[0043] In some embodiments of the present invention, the pads and electronic devices are interconnected via conductive adhesive 70 (or solder). Preferably, the conductive adhesive interconnection between the pads and electronic devices in the embodiments of the present invention significantly reduces the temperature requirements of materials and processes and expands the range of materials available compared to soldering.

[0044] In some embodiments of the present invention, an adhesive layer 80 is further provided between the electronic device and the stretchable substrate. This embodiment is mainly used for fixing the electronic device before packaging, avoiding the risk of misalignment, peeling, or falling off during transfer, dispensing, and other processes.

[0045] In some embodiments of the present invention, the length of the contact surface between the first trace 21 and the second trace 22 is not less than 1 / 3 of the perimeter of the combined pattern of the second trace 22 and the pad 23, and the contact surface between the first trace 21 and the second trace 22 has at least one inflection point.

[0046] In this embodiment, the length of the contact surface between the first and second traces with different stretchability is designed to be no less than 1 / 3 of the perimeter of the combined pattern between the second trace and the pad. This effectively increases the size of the contact surface between the first and second traces with different stretchability. At the same time, the contact surface is designed to have at least one inflection point, that is, the contact surface between the first and second traces includes at least two contact surfaces in different directions, which can reduce the risk of open circuit when stretched in a single direction.

[0047] Among them, the longer the contact surface between the first and second traces with different stretchability and the more inflection points there are on the contact surface, the better its tensile breaking performance. Those skilled in the art can select from 1 / 3 of the perimeter to the entire perimeter of the combined pattern between the second trace and the pad according to actual needs, including but not limited to not less than 1 / 2 perimeter, 2 / 3 perimeter, etc.

[0048] Furthermore, the contact surface between the first and second traces can be an arc structure, in which case it can be considered that there are the most inflection points on the contact surface; specifically, the central angle of the arc structure can be selected between 120° and 360°; furthermore, the central angle of the arc structure can be 120°, 150°, 180°, 240°, etc.

[0049] One of the main objectives of this embodiment is to increase the contact area between the flexible, stretchable electronically dispensed encapsulated area and the undispensed encapsulated area. To achieve this effect, the main approach is to design the local area where the first and second traces connect to be wider than the original trace. Furthermore, to reduce the overall layout size of the trace, the first trace can have at least one variable diameter structure in the direction away from the second trace, meaning the trace width gradually decreases, thus reducing the overall layout size of the trace. Accordingly, those skilled in the art can understand that, compared to traditional traces, the entire trace is widened in the local area where the first and second traces connect.

[0050] Furthermore, there is also a difference in stretchability between the first trace affected by the tensile packaging and the first trace not affected by the tensile packaging. Therefore, in order to reduce the risk of tensile breakage at the contact surface between the two, the contact surface can also adopt the contact surface design between the first trace and the second trace as described above. Therefore, the specific solution can be referred to the above embodiments, and this application will not elaborate further.

[0051] In some embodiments of the present invention, the window structure on the stretchable package can be a regular or irregular shape such as a triangle, square, rectangle, rhombus, trapezoid, or circle. Preferably, the window structure on the stretchable package in the present invention can be circular, which can be combined with the arc structure of the tensile-resistant package to improve the pattern consistency of the package structure and enhance the user experience.

[0052] In actual packaging structures, electronic devices typically have at least two electrode pins, requiring separate connections to at least two pads. Therefore, those skilled in the art should understand that in this embodiment of the invention, at least two flexible conductive lines interconnect with the electronic device are present, connected to each other via the electronic device, with their pads close to and opposite each other. Thus, the window of the stretchable package should contain two pads and corresponding second traces connected to those pads.

[0053] In some embodiments of the present invention, the overall length (i.e., 2*L1) of the second trace 22 (two second traces) within the window 40 of the stretchable package 30 is not greater than the aperture L2 of the window 40 and not less than 1 / 5 of the aperture L2 of the window 40 (i.e., the length L1 of a single elastic conductive line of the second trace 22 is not less than 1 / 10 of the aperture L2 of the window 40), thereby avoiding the problem that the influence of the gradient change region of the constructed stretchable performance is not obvious due to the length of the second trace being too small.

[0054] Furthermore, in this embodiment of the invention, the overall length of the second trace (two second traces) within the window of the stretchable package is no greater than 4 / 5 of the window diameter (i.e., the length of a single elastic conductive line second trace is no less than 4 / 10 of the window diameter), so as to avoid affecting the design of the pad area.

[0055] Specifically, in the embodiments of the present invention, the overall length of the second trace (two second traces) inside the window of the stretchable package can be 1 / 5, 2 / 5, 3 / 5, 4 / 5 of the window diameter, etc. (that is, the length of the second trace of a single elastic conductive line is 1 / 10, 2 / 10, 3 / 10, 4 / 10 of the window diameter, etc.).

[0056] In some embodiments of the present invention, the aperture L2 of the window 40 of the stretchable package 30 can be between 2 mm and 10 mm, which can reduce the impact of an excessively large gradient change region in stretchability on the overall stretchability of the stretchable electronic product. Specifically, the aperture L2 of the window 40 of the stretchable package 30 in the present invention can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm.

[0057] Preferably, in this embodiment of the invention, the window of the stretchable package is circular with a diameter of 5mm, and the overall length of the second trace (two second traces) inside the window is 2 / 5 of the window diameter (i.e., the length of the second trace of a single elastic conductive line is 2 / 10 of the window diameter).

[0058] This invention also discloses a flexible and stretchable phototherapy patch, comprising: the flexible and stretchable encapsulation structure described in any of the above claims. The phototherapy patch is applicable to various areas, including but not limited to the face, eyes, chin, torso, hands, and legs, and can be designed to fit different areas. Specifically, the phototherapy patch may include: a phototherapy facial mask, a phototherapy eye patch, etc.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flexible and stretchable packaging structure, characterized in that, include: Stretchable substrate; The elastic conductive line disposed on the stretchable substrate includes a first trace, a second trace and a pad connected in sequence. A stretchable package disposed on the stretchable substrate, covering a first trace of the elastic conductive line, and having a window thereon for exposing the pads and a second trace of the elastic conductive line. Electronic devices located on pads within the window; The tensile-resistant package reinforces the connection between the electronic device and the pad, while also covering the second trace within the opening and the stretchable package around the opening. A portion of the first trace is vertically opposite to a portion of the stretchable package and a portion of the tensile-resistant package.

2. The flexible and stretchable packaging structure according to claim 1, characterized in that, The height of the electronic device is greater than the height of the stretchable package.

3. The flexible and stretchable packaging structure according to claim 1, characterized in that, The tensile-resistant encapsulation is formed by dispensing adhesive to create an arc structure, which also covers the electronic device.

4. The flexible and stretchable packaging structure according to claim 2, characterized in that, The electronic device is an LED lamp bead, and the top surface of the tensile-resistant package is a planar structure parallel to the top surface of the LED lamp bead.

5. The flexible and stretchable packaging structure according to claim 1, characterized in that, The pads are interconnected with the electronic devices via conductive adhesive or solder.

6. The flexible and stretchable packaging structure according to claim 1, characterized in that, An adhesive layer is also provided between the electronic device and the stretchable substrate.

7. The flexible and stretchable packaging structure according to claim 1, characterized in that, The length of the contact surface between the first trace and the second trace is not less than 1 / 3 of the perimeter of the combined pattern of the second trace and the pad, and there is at least one inflection point on the contact surface between the first trace and the second trace.

8. The flexible and stretchable packaging structure according to claim 1, characterized in that, The tensile-resistant encapsulation layer is a non-stretchable structure.

9. The flexible and stretchable packaging structure according to claim 1, characterized in that, The elastic conductive layer is formed by printing with low-temperature conductive paste, and its elongation at break is not less than 50%.

10. A flexible and stretchable phototherapy patch, characterized in that, Includes the flexible stretchable packaging structure according to any one of claims 1-9.

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